WQRA HealthStream - Issue 62

Issue 62

Public Health Newsletter of Water Quality Research Australia

In this Issue:

June 2011

Recreational Water Exposures

Recreational Water Exposures

1

IPR for Western Australia?

4

Safe Drinking Water Act for South Australia 5 News Items

6

Circulation Report

7

From The Literature

7

Web Bonus Articles Arsenic Disinfection byproducts Fluoridation Iodine

A team of US researchers has published a new study of recreational water exposures that combines selfreported estimates of water ingestion from recreational water users with volume estimates based on measurement of an ingested chemical in the urine (1). Both techniques have been used separately in previously published studies but this is the first instance where they have been combined. By examining the correlation between the two types of estimates, the researchers developed “translation factors” which allow conversion of self-reported exposures into volumetric terms. This methodology has the potential to provide more certainty about recreational water exposure volumes to help refine recreational water quality guidelines.

Legionella Microbial Risk Assessment Norovirus POU Treatment Supply Interruption Mailing List Details

Editor

20

Martha Sinclair

Assistant Editor Pam Hayes

WQRA Internet Address: www.wqra.com.au A searchable Archive of Health Stream articles, literature summaries and news items is available via the WQRA Web page.

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Current World Health Organisation Guidelines for recreational water quality assume that 20 – 50 mL of water is swallowed for each hour of swimming activity but these assumptions were developed on the basis of expert consensus rather than experimental data. Dutch researchers have previously carried out studies where recreational water users were asked to describe water ingestion in terms of “none or only a few drops”, “one or two mouthfuls”, “three to five mouthfuls” etc. (2, 3). For reference, participants were told one or two mouthfuls was equivalent to a shot glass, three to five mouthfuls equal to a coffee cup etc. These estimates were then translated to millilitre volumes by collecting data on the actual volumes of mouthfuls collected experimentally from a panel of 119 males and females of various ages, and using this to construct a distribution using Monte Carlo sampling. It was assumed that “none or a few drops” was a continuous uniform distribution from 0

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to 5mL. These studies estimated that men swallowed an average of 27 to 34mL per swimming event, while women swallowed 18 to 23mL. Children were estimated to swallow 31 to 51mL per event.

A direct method for measuring water ingested while swimming was used in a pilot study by US researchers (4). This group measured cyanuric acid in the urine of subjects who had swum in an outdoor pool. Cyanuric acid is a non-toxic chemical which is used in outdoor pools to protect chlorine from UV degradation. If ingested, it is not metabolised and is reported to be 100% excreted in urine within 24 hours. Thus by measuring the concentration of cyanuric acid in the swimming pool water and the 24-hour urine sample, and measuring the volume of urine excreted, it was possible to calculate the volume of water ingested. This study found that adults on average swallowed 16mL during a 45 minute swimming session, while children swallowed an average of 37mL in the same time.

The new study combining these two approaches was carried out in Chicago during the spring and summer of 2009. It involved two separate components: • a prospective cohort study of people undertaking limited contact water recreation (not swimming) at waterways around Chicago. The researchers did not control the choice of activity undertaken or the consequent water exposures. Participants were recruited at piers, harbours and beaches around Lake Michigan and other lakes and rivers. Also included were people using the Chicago Area Waterways System (CAWS) which receives most of its water inflow from secondary treated but undisinfected wastewater.

• a controlled exposure study at public outdoor swimming pools. Participants were enrolled at participating pools and undertook a range of activities including swimming.

To be eligible for the study people had to be 6 years of age or older, not to have swum in a pool during the previous 4 days, and not to have been diagnosed with renal disease. Participants in the waterways group undertook any one of five activities (canoeing, fishing, kayaking, motor boating, rowing) according to their own choice. The duration of activity was not

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limited. The swimming pool group undertook the following activities: • canoeing or kayaking in a large swimming pool including practicing rolling if desired. Accidental or deliberate capsize also occurred for some participants.

• simulated fishing - casting a toy rod with plastic fish attached into the pool, reeling in the fish, removing the fish from the hook then replacing it and repeating the process at 5 minute intervals.

• wading/splashing in shallow pools, some with fountains. These participants were told to walk/play/splash in the water but not to swim.

• swimming laps in a large pool • head immersion, consisting of standing in water, immersing the head 3 times in a 10 min interval.

All of these activities (except for head immersion) were done for a 1 hour period. After the recreational water activities, participants in both groups were interviewed and asked to estimate the volume of water they had swallowed as “none”, “a drop or two”, “a teaspoonful” or “one or more mouthfuls”.

Those in the swimming pool arm were also asked to collect urine samples for 24 hours immediately after the activity. Samples of pool water were collected for analysis of cyanuric acid levels. People were permitted to participate on more than one occasion provided there were 4 days clear between exposures.

Among the swimming pool participants, 62% took part in more than one exposure session. The frequency of repeat participation was only 6% among those in surface waterways group.

Of the 685 participants in the swimming pool group, 665 (97.1%) gave urine specimens. However 63 samples could not be used because the corresponding pool water samples showed undetectable levels of cyanuric acid despite assertions from pool managers that this chemical was used in the pool. A further 8 urine specimens were excluded as their volumes were considered too low to be plausible for a 24-hour sample. Assays of cyanuric acids levels in pool water by the published HPLC (high pressure liquid chromatography) method were straightforward, with satisfactory quality assurance results. Application of this method to urine specimens proved to be problematic, with poor performance on quality

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assurance tests. There was a strong matrix effect in urine and an unacceptable rate of both false positive and false negative results. An alternative LC/MS/MS (liquid chromatography tandem mass spectrometry) assay method was used for a subset of 27 urine specimens. This method proved to have satisfactory performance in both urine and water samples. Results from the HPLC method were not used or analysis.

Statistical tests showed that observations from repeat exposures for the same person could be treated as independent events. A total of 2705 self-reported ingestion observations were available for analysis from the waterways group, and 662 self-reported observations from the swimming pool group. In the waterways group less than 5% of participants in any activity reported any water ingestion. In the swimming pool group, no water ingestion was reported by the fishing group or by negative control subjects who simply walked around the pool.

Swimmers reported the highest volumes of water ingestion, with 27.2% reporting ingestion of at least one mouthful of water. Those engaged in canoeing and kayaking in pools also had relatively high frequencies of ingesting at least one mouthful of water (3.9% and 6.7% respectively). The investigators noted that in the waterways group, capsizing was reported only by 5.4% of canoers and 3.4% of kayakers. In the swimming pool group the respective frequencies were 27.6% and 38.5%, and capsizing was often deliberate. Not surprisingly, capsizing was a strong predictor of higher selfreported water ingestion volumes. In the waterways group, capsizing was about 9 times less frequent in the CAWS than in other surface waters. This presumably reflects user awareness of the presence of wastewater in the CAWS. Among the participants with LC/MS/MS urine analysis results, few reported swallowing a drop or a teaspoon of water, and these categories were combined for analysis. Log10-transformed values of calculated water ingestion were associated with the ordinal levels of self-reported ingestion (none, dropteaspoon, mouthful), with an r2 of 0.24, p=0.009. For those who had reported no ingestion (n=15) the mean ingestion calculated from urine analysis was 3.5 mL (median 2.0 mL, range 0.3 to12.7mL, 95% upper

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confidence limit (UCL) 10.6 mL). For those reporting ingestion of a drop-teaspoon (n=6) the mean value was 10.8 mL (median 7.9 mL, range 0.7 to 27.6 mL, UCL 31.4 mL), while for those reporting ingestion of a mouthful or more (n=6) the mean value was 20.3 mL (median 11.1 mL, range 1.2 to 80.9 mL, UCL 79.3mL). These values were used as “translation factors� to estimate the mean, median and UCL for water ingestion for type of recreational activity based on participant self-reported estimates.

It was estimated that the UCL for water ingestion for participants in rowing, motor boating, fishing, wading/splashing and non-capsizing canoeing and kayaking was about 10-12 mL per hour. For those who capsized during canoeing or kayaking, the UCL for ingestion was 17-20 mL per hour. Swimming produced the highest rate of ingestion with a UCL of 35mL per hour. Where the same activity was carried out in waterways and in swimming pools, there was reasonably good agreement between ingestion volume estimates, although the authors note that participant behaviour may have been influenced by their perception of the relative safety of different water types. The volume estimates for swimming exposure derived from this study are consistent with data from previous work. They also provide a greater level of detail for relative exposure volumes for different activities. Unfortunately due to difficulties with the HPLC assay method, the number of observations with both self-reported estimates and urine excretion measurements was limited, but nevertheless this study has strengthened confidence in exposure estimates for a range of recreational exposures.

(1) Dorevitch S, Panthi S et al. (2011) Water ingestion during water recreation. Water Research 45(5):2020-2028.

(2) Schijven J and AM de Roda Husman (2006). A survey of diving behaviour and accidental water ingestion among Dutch occupational and sport divers to assess the risk of infection with waterborne pathogenic microorganisms.

Environmental Health Perspectives 114(5): 712-717.

(3) Schets FM, Schijven JF and de Roda Husman AM. (2011) Exposure assessment for swimmers in bathing waters and swimming pools. Water Research 45(7): 23922400.

(4) Dufour AP, Evans O et al. (2006). Water ingestion during swimming activities in a pool: A pilot study.

Journal of Water and Health 4: 425-30.

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IPR for Western Australia?

The Western Australian state government has indicated it may fast-track adoption of indirect potable reuse (IPR) of recycled water to supplement the water supply for the state capital, Perth. The announcement comes amid rising concern over dwindling water supplies for the city of over 1.6 million people. In contrast to the eastern states of Australia which received drought-breaking rain in recent months, the southern region of Western Australia is still experiencing severe drought conditions. The winter of 2010 was one of the driest ever recorded in the region, resulting in very low inflows to surface water dams and little replenishment of the shallow aquifers that have traditionally been the major source of water for the city of Perth. Rainfall during the first half of 2011 has also been well below the long term average, and some experts have predicted severe water shortages for the 2011/2012 summer season if rainfall remains low over the next few months.

The water supply for Perth is drawn from a range of sources including groundwater, surface water dams and desalinated seawater. These sources are linked into an integrated water supply system which also supplies some regional areas around Perth. Almost half of the water supply originates from dams in the Darling Range and the southwest of the state, however these surface water sources are currently at only 22.8% of their total capacity. Groundwater is taken from a number of bores drawing on the Gnangara mound (a large shallow unconfined aquifer to the north of the city) and the smaller Jandakot mound aquifer in the south. The Gnangara mound has historically provided around 60% of Perth’s drinking water, but been has showing signs of depletion for a number of years with average groundwater levels dropping around two metres since 1997. In response to increasing stresses on traditional groundwater and surface water sources, Perth was the first city in Australia to adopt desalination as a substantial component of the public water supply.

The city’s first desalination plant at Kwinana commenced water supply operations in November 2006, and currently provides about 17% of Perth’s 244 gigalitre annual requirements. A second

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desalination plant is nearing completion, with water production scheduled to commence in late 2011. The plant will initially produce 50 gigalitres per year with the possibility of future expansion to double that capacity.

Despite these long term water shortages, Perth currently recycles only a small percentage of the sewage effluent produced by the city. However, water recycling and storage of treated water in underground aquifers is seen as potentially a major avenue to augment future water supplies. A trial scheme for replenishment of groundwater aquifers using highly treated recycled water commenced at the end of November 2010. Treated wastewater from the Beenyup Wastewater Treatment Plant is being subjected to advanced water treatment (including ultrafiltration, reverse osmosis filtration and UV disinfection) before being pumped into a deep confined aquifer which is separate from the shallow aquifer that currently supplies drinking water. This design was deliberately adopted so that the health and environmental safety of aquifer recharge could be assessed and demonstrated under local conditions without impacting on current drinking water supplies.

The project also includes a Visitor Centre to inform and educate the community about groundwater replenishment throughout the trial.

The trial involves extensive monitoring of plant operations, treated water quality, changes in groundwater quality and validation of predictions from groundwater flow models. It will also document the costs of water production by this technique. The outcomes are being evaluated by the WA Department of Health, WA Department of Water and the WA Department of Environment and Conservation to determine whether such schemes are a safe and sustainable option for water supply. It was initially planned to run the scheme for three years prior to assessing the outcomes, however according to media reports, the Western Australian Water Minister recently wrote to Water Corporation and the Department of Water asking whether the evaluation period could be shortened and the project fast-tracked into a full scale scheme should outcomes prove satisfactory.

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The water quality monitoring program for the trial involves testing for microbial pathogens, over 240 human health-related chemical parameters and a further six parameters that are relevant for ecological health. Movement of the introduced water through the aquifer is being mapped using 22 monitoring bores which are located at five sites around the water injection bore. Prior to the commencement of aquifer recharge, an 18 month monitoring program was undertaken to document the baseline conditions in the aquifer. The quality of the treated water for injection to the aquifer is assured by continuous monitoring of four critical performance criteria at the Beenyup Wastewater Treatment Plant, and a further nine critical performance criteria at the Advanced Water Recycling Plant. All water quality monitoring results for the first seven months of operation have complied with health and environmental targets. The trial plant is currently producing up to 5 megalitres of water per day for aquifer recharge, but if the trial is judged to be successful, production from the current Beenyup Wastewater Treatment Plant could be scaled up to around 25 gigalitres per year. Additional advanced treatment and aquifer replenishment schemes could also be developed for other sewage treatment plants serving Perth, potentially providing up to 115 gigalitres per year overall.

Even if a decision is made by the Western Australian state government to shorten the trial groundwater replenishment project and proceed with replenishment of drinking water aquifers, it is expected that about 18 months would be required for construction and commissioning of a full scale Advanced Water Recycling Plant. Queensland was the first Australian state to construct plants of this type, with the intention of supplementing the drinking water supply for Brisbane via addition of highly treated recycled water to the Wivenhoe Dam. However, to date the recycled water has been used only for industrial purposes, and the Queensland state government has set a trigger level of 40% dam capacity before drinking water augmentation would be implemented for Brisbane. Wivenhoe Dam is currently at 84% capacity, and depending on rainfall patterns in the two states over the next few years, Western Australia may yet become the first Australian state to embark on indirect potable reuse.

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Safe Drinking Water Act for South Australia The Safe Drinking Water Act (2011) was passed by the South Australian Parliament on Tuesday 17 May this year. The Act provides specific legislation of drinking water quality in South Australia and will replace sections of the Food Act 2001 and Food Regulations 2002 for South Australia which previously covered drinking water supplies. The Department of Health will have primary responsibility for administering the Act. Specific regulations required for implementation of the Act will be developed in consultation with stakeholders over the next few months. Regulation of bottled and packaged water will remain under the Food Act. The legislation has many similarities with similar legislation already enacted in several other Australian states. It recognises the Australian Drinking Water Guidelines as the authoritative reference for drinking water quality and the management of drinking water supplies, and specifies a risk management approach for ensuring the safety and quality of drinking water supplied to the public. The Act requires drinking water providers to be registered, and to develop and implement a risk management plan for each water supply, including an approved monitoring program and incident identification and notification protocol.

Regular independent inspection or audit of drinking water supplies will also be required, and approval requirements for drinking water scheme auditors and inspectors will be specified.

The majority of South Australian residents receive drinking water from the state-owned company South Australian Water, however it is estimated that about 500 other organisations in the state also provide drinking water to the public. These include local councils, independent town supplies, community supplies, schools, hospitals, water carters, residential care facilities and accommodation premises. The final version of the Act contains a number of provisions that were introduced in response to a stakeholder consultation process. These include: • exemption for rainwater tank supplies providing that members of the public are made aware of the use of this source for drinking. This is

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consistent with existing advice from the state Department of Health that drinking rainwater from well-maintained roof catchments and tanks is low risk and is a matter of personal choice.

Currently 23% of households in South Australia use rainwater as their main source of drinking water. Rainwater is also used by many small restaurants and accommodation venues across the state.

• exemption for rainwater and bore water provided in open spaces such as parks and reserves, where it is reasonable to expect that the public would bring their own drinking water and not usually expect to rely on the provision of drinking water at that place.

• combining drinking water inspections with other audits and existing accreditation programs where possible to minimise the cost and administrative burden on water providers and local agencies responsible for inspections. It is expected that different levels of accreditation will be required for auditors depending on the size and complexity of systems they will audit.

The Department of Health is developing a range of guidance materials, templates, checklists and proformas to assist small and medium providers to meet the requirements of the new regulations.

Training will also be offered for inspectors. The department will also maintain the register of drinking water providers and supply details of relevant providers to local councils. The operations of SA Water are already in compliance with the requirements of the Act.

News Items Murray Valley Encephalitis Deaths As reported in the last issue of Health Stream, heavy summer rainfall in many parts of Australia has led to a rise in mosquito numbers and consequent upsurge in mosquito-borne diseases. A total of 14 cases of infection by the Murray Valley Encephalitis (MVE) virus have been reported to national surveillance authorities between 1 January and 31 May this year, in comparison to 18 cases in total over the previous 10 years. Three confirmed deaths and one suspected death have been attributed to the MVE virus, with a

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number of other people still hospitalised with serious illness. One confirmed death occurred in Western Australia, and another in South Australia. The suspected MVE death occurred in Victoria. The fourth victim was a Canadian tourist who died after returning home. The young woman had visited Australia’s Northern Territory for a 10-day holiday after spending 6 months in New Zealand. She was admitted to hospital a few days after arriving home in Canada and died 8 days later.

Keynotes Announced for 2011 Water and Health Conference: Where Science Meets Policy 3-7 October 2011, Chapel Hill, North Carolina, USA Attendees of this year’s conference will have the opportunity to hear four keynote presentations from renowned experts spanning human rights, water resources, policy, practice, and financing. Keynote Presenters are Catarina de Albuquerque, Charles J. Vörösmarty, Jaehyang So and Frank Rijsberman.

See: http://whconference.unc.edu/keynotes.cfm Registration is now open; early bird rate ends 31 July 2011. http://whconference.unc.edu/register.cfm Cryptosporidium Hits Second Swedish Town Another waterborne Cryptosporidium outbreak has occurred in Sweden only a few months after the large outbreak that affected the town of Östersund in November last year. The affected town is Skellefteå in the north of the country. The outbreak was recognised in mid-April and appears to be associated with a waterworks that supplies about 40,000 people.

The water supply is drawn from a river and treated by chemical precipitation, rapid filtration and hypochlorite disinfection before distribution. Over 12,000 people have responded to an internet questionnaire by the local council and about 50% of these have reported illness. The protozoan parasite has been detected in ill people but not drinking water, however an epidemiological investigation showed a significant association with consumption of municipal tap water and a dose-response relationship with the volume of water ingested. Authorities at Skellefteå have declared a boil water alert which will remain in force until a UV treatment unit is installed at the water treatment plant and contaminated water has been flushed from the distribution system.

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Circulation Report – Issue 62 June 2011 Circulation for the print version of this issue is 2133 copies, with readers in 65 countries.

In addition, 2287 readers are registered for email notification of new issues.

Australia Algeria Argentina Austria Bangladesh Belgium Brazil Cameroon Canada Chile Chinese Taipei Cyprus Czech Republic Egypt Finland France Germany

1571 1 1 3 1 1 1 5 44 6 16 1 1 6 2 22 33

Ghana Greece Hong Kong Hungary India Indonesia Ireland Iran Israel Italy Ivory Coast Japan Jordan Lebanon Lesotho Lithuania Luxembourg

1 7 16 1 33 8 1 1 10 3 1 47 2 1 1 1 1

From the Literature Web-bonus articles Summaries of these additional articles are available in the PDF version of Health Stream on the WQRA web page: www.wqra.com.au The association between arsenic exposure from drinking water and cerebrovascular disease mortality in Taiwan. Cheng TJ, Ke DS and Guo HR. (2010) Water Research, 44(19); 5770-5776.

Effects of drinking arsenic contaminated water on spontaneous abortion and neonatal mortality.

Rahamatullah M, Ara KZG et al. (2010) Advances in Environmental Biology, 4(2); 152-154.

Pre-and postnatal arsenic exposure and child development at 18 months of age: A cohort study in rural Bangladesh. Hamadani JD, Grantham-McGregor SM et al. (2010) International J of Epidemiology, 39(5); 1206-1216.

Socioeconomic status and exposure to disinfection byproducts in drinking water in Spain. Castano-Vinyals G, Cantor KP et al. (2011) Environmental Health: A Global Access Science Source, 10:18.

Drinking water fluoridation and osteosarcoma incidence on the island of Ireland. Comber H, Deady S et al. (2011) Cancer Causes and Control 22(6): 919-924.

Shiga toxin-producing Escherichia coli O100:H-: stx2e in drinking water contaminated by waste water in Finland. Lienemann T, Pitkanen T et al. (2011) Current Microbiology, 62(4); 1239-1244.

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Malaysia Morocco Myanmar Nepal Netherlands New Caledonia New Zealand Nigeria Norway Oman Pakistan Palestine Papua New Guinea Philippines P.R. China Russia Saint Lucia

23 5 1 6 11 1 19 13 2 2 3 3 6 5 1 2 1

Singapore Slovenia South Africa Spain Sri Lanka Switzerland Thailand Togo UAE UK USA Yugoslavia Zambia Zimbabwe

5 3 6 1 3 4 10 1 3 49 93 1 1 1

Mycobacterium lentiflavum in drinking water supplies, Australia. Marshall HM, Carter R et al. (2010) Emerging Infectious Diseases, 17(3); 395-402.

Novel risk factors associated with hepatitis E virus infection in a large outbreak in northern Uganda: results from a case-control study and environmental analysis. Howard CM, Handzel T et al. (2010) American J of Tropical Medicine and Hygiene, 83(5); 1170-1173.

Perchlorate in drinking water during pregnancy and neonatal thyroid hormone levels in California.

Steinmaus C, Miller MD and Smith AH. (2010) J of Occupational and Environmental Medicine, 52(12); 12171224.

Pharmaceuticals in drinking water: local analysis of the problem and finding a solution through awareness.

Leal JE, Thompson AN and Brzezinski WA. (2010) J of the American Pharmacists Association 50(5); 600-603.

Bactericidal paper impregnated with silver nanoparticles for point-of-use water treatment.

Dankovich TA and Gray DG. (2011) Environmental Science and Technology, 45(5); 1992-1998.

Public perception about drinking jar water and its bacteriological analysis. Subedi M and Aryal M. (2010) Nepal Medical College Journal 12(2); 110-114.

A waterborne outbreak of epidemic diarrhea due to group a rotavirus in Malatya, Turkey. Koroglu M, Yakupogullari Y et al. (2011) New Microbiologica, 34(1); 17-24.

An assessment of microbiological water quality of six water source categories in north-east Uganda. Parker AH, Youlten R et al. (2010) J of Water and Health, 8(3); 550-560.

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Arsenic

found in Region V and water arsenic concentrations in its largest city, Valparaiso are close to 1 µg/l.

Evidence from Chile that arsenic in drinking water may increase mortality from pulmonary tuberculosis.

Smith, A.H., Marshall, G., Yuan, Y., Liaw, J., Ferreccio, C. and Steinmaus, C. (2011) American Journal of Epidemiology, 173(4); 414-420.

Tuberculosis is a major worldwide public health problem with over 2 million deaths and 9 million new infections currently occurring each year. Only about 5-10% of people with normal immune function who are infected with the causative organism Mycobacterium tuberculosis develop active (infectious) tuberculosis during their lifetime.

Illnesses which involve immune suppression (HIV infection, diabetes mellitus, end stage renal disease, chronic lung diseases) are known to increase the risk of developing active tuberculosis. Arsenic in drinking water has been found to cause immune suppression and chronic lung diseases. This study assessed arsenic in drinking water and mortality from pulmonary tuberculosis in northern Chile.

The study was undertaken in Region II in northern Chile which had a population of 477,000 in 2000. All cities and towns in Region II have municipal water as their only source of drinking water. The concentration of arsenic in the municipal water sources in this region has been measured since 1950.

Region II experienced some abrupt changes in arsenic water concentrations, in particular the main city of Antofagasta (combined with nearby Mejillones, current population = 318,000) changed its water source in 1958 to a piped system with water coming from two arsenic-contaminated rivers, and water concentrations of arsenic immediately increased from about 90 µg/l to an average of about 870 µg/l. Then in 1971, arsenic concentrations were abruptly reduced after the installation of an arsenic removal plant with concentrations initially reduced to about 110 µg/l and improving over the years so that the water arsenic concentration is now less than 10 µg/l. Region V of Chile was selected as the referent population with a population about 4 times that of Region II. Arsenic contaminated water has not been

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For the years 1958-1970, electronically recorded death data were not available, and information had to be obtained from written death certificates. As coding of all death records for Chile for this period was not feasible, a subset of 140,194 death certificates from Regions II and V were coded according to the International Classification of Diseases (ICD), Ninth Revision. To avoid bias, coding was done in a blinded fashion, with death certificates from the two regions mixed together. Computerised mortality data first became available in 1971 and these data were already coded to the ICD, Ninth Revision for all regions of Chile for the years 1971-1979 (excluding 1976 which was not completed because of political unrest). Coded mortality data for all regions of Chile for the years 1980-2000 were obtained from the Ministry of Health. The National Institute of Statistics provided annual estimates of the population living in Regions II and V for the period 1958-2000, stratified by age and gender.

Arsenic exposure was split in to 3 time periods: 1958-1970 (the period of high exposed in Region II), 1971-1985 (intermediate exposure) and 1986-2000 (low exposure). Mortality rate ratios were estimated using Poisson regression analysis, comparing Region II with Region V in each exposure time period for men and women separately, first stratified by age in 10-year strata and then for all ages combined and adjusted for age. To further identify trends in pulmonary tuberculosis mortality rate ratios over time, 5-year mortality rate ratio estimates by calendar year were plotted. For each year in the study period, the rate ratio for that year, combined with the 2 years before and the 2 years after it was calculated.

For the 1958-1970 time period, mortality rate ratios were close to 1 (men: rate ratio (RR) = 1.09; women rate ratios were 1.13). For the period 1971-1985, rate ratios were considerably increased (men: RR = 1.71, P < 0.001; women: RR = 1.60, P < 0.001). Rate ratios were still elevated in the period 1986-2000 however they had reduced to 1.58 for men and 1.48 for women. Men had a much greater number of tuberculosis deaths than women and therefore time

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trend mortality rate ratios were calculated for males only. Age-adjusted 5-year rate ratios and 95% confidence intervals (CI) for pulmonary tuberculosis mortality for men in Region II compared with Region V for the years 1958-2000 were calculated. A clear latency pattern was found. Initially, pulmonary tuberculosis mortality rates were virtually the same for men in Region II compared with men in Region V (RRs ~1.0). An increasing trend was found starting around 1968, 10 years after high arsenic exposure from drinking water began. The highest 5-year rate ratio was for the period 1982-1986 (RR = 2.1, 95% CI: 1.7, 2.6; p <0.001). The rate ratios subsequently fell so that in the last 5-year period, 1996-2000, the rate ratio was close to 1 (RR = 1.3, 95% CI: 0.9, 1.8).

Compared to the expected rate ratios in Region V, it was estimated that there were 359 excess pulmonary tuberculosis deaths in Region II in the period 19681995 among men and 95 among women.

This study presents the first evidence that suggests that increased mortality from pulmonary tuberculosis could be yet another serious outcome from exposure to arsenic in drinking water. If the findings of this study are verified, there will be some important public health implications as some of the largest arsenic-exposed populations are in developing countries with widespread tuberculosis. If arsenic in water does increase mortality from tuberculosis then particular attention will be required to ensure that patients with tuberculosis are not drinking arseniccontaminated water.

Comment The authors note limitations in the study including lack of information on risk factors such as HIV infection, silicosis and diabetes, and the absence of confirmatory medical records for the high arsenic region during the period where the greatest adverse effects on mortality were found. Further studies, preferably of a prospective design, are needed to investigate this issue.

Disinfection byproducts Water disinfection by-products and bladder cancer: Is there a European specificity? A pooled and meta-analysis of European case-control studies.

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Costet, N., Villanueva, C.M., Jaakkola, J.J.K., Kogevinas, M., Cantor, K.P., King, W.D., Lynch, C.F., Nieuwenhuijsen, M.J. and Cordier, S. (2011) Occupational and Environmental Medicine 68: 379385.

An association between the risk of bladder cancer and the exposure to trihalomethanes (THMs) has been suggested in a number of epidemiological studies. An international pooled analysis published in 2004 examined long-term exposure to chlorinated byproducts and the risk of bladder cancer in six casecontrol studies from the USA, Canada and Europe and statistically significant excess risks were found among men. This current study was undertaken as part of the European Commission funded Health Impacts of Long-Term Exposure to Disinfection ByProducts in Drinking-Water (HiWate) project which examined the human health risks (for cancer and adverse reproductive outcomes) associated with longterm exposure to low levels of disinfectants and DBPs in drinking water. This study was restricted to analysis of data from European studies and included research undertaken after the 2004 pooled analysis.

The different disinfection strategies and regulations applied in Europe compared to North America were justification for such an analysis, as well as the need for specific health-impact assessments in Europe.

Data was pooled from three European case-control studies, conducted in France, Finland and Spain (5467 individuals: 2381 cases and 3086 controls).

The age range in the pooled analysis was 30-80 years at diagnosis. The environmental exposure to THM that was assessed in these studies was the annual average total THM (TTHM) level (Âľg/l) in tap water during the residential history of the subjects, calculated as the year-by-year sum of the mean annual TTHM level at each residence, divided by the number of years with no missing data. A common 40-year exposure window (from 45 years to 5 years before diagnosis) was used. The French and Spanish samples also had data available on the duration of exposure to a surface chlorinated tap water (expressed in years) and this was used as a second environmental indicator of exposure. All of the three studies collected the mean individual daily consumption of tap water, total fluids (including tap

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water and other beverages) and coffee, expressed or converted into litre/day. An indicator of the cumulative exposure (mg) to TTHM via ingestion over the 40-year exposure window was derived by combining the environmental exposure information and the individual tap water intake: the product of the sum of the annual average TTHM concentrations (µg/l) in the exposure window multiplied by the average daily tap water intake (l/day) x 365).

It was found that about one-quarter of the subjects were not exposed to THMs during the exposure window. Of those that were exposed, the median TTHM concentration was 30 µg/l (max = 145 µg/l).

Among men, there was a significant increasing trend in bladder-cancer risk with increasing TTHM exposure, but no consistent association was found among women. Men exposed to average TTHM concentrations greater than 5 µg/l had a higher risk than men exposed to less than 5 µg/l. Statistically significant odds ratios (ORs) were found up to 1.35 for men exposed to concentrations above 25 µg/l.

The generalised additive modelling confirmed that the risk of bladder cancer increased with exposure levels. The analysis of the effect of duration of exposure to chlorinated surface water was limited to 2065 subjects from France and Spain for which information was available about the source of water at their residence for at least 70% of the 40-year exposure window. A statistically significant positive trend between the duration of exposure and the risk of bladder cancer was found among men, but not among women. The effect of duration disappeared when it was introduced into the model along with average residential TTHM level. This suggests that the risk observed is driven by the average level. A two-step meta-analysis was used to explore the heterogeneity of the pooled database and to consider specific covariates of the original data. In the metaanalysis, results for women were both inconsistent and not significant. The excess risk for exposed compared with non-exposed men varied between the original studies and ranged from 1.16 (Finland) to 1.79 (France). The test for heterogeneity of the ORs between studies was not significant (p=0.45). The combined (random effect) excess risk was statistically significant: 1.27 (CI = 1.03 to 1.58). ORs were the lowest in Finland for all levels of exposure.

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The combined ORs (random effects) indicated that the risk of bladder cancer increased with level of exposure and that it was statistically significant above 50 µg/l. The meta-analysis indicated a significant linear trend (p=0.01). The ORs obtained from the meta-analysis were systematically higher than those obtained from the pooled analysis.

A meta-regression of the complete set of case-control studies, including the three American and Canadian studies from the original pooled analysis was conducted to compare the results in the European and the North American studies. The meta-regression indicated no significant ‘European’ effect of exposure to an average TTHM level. For the risk of bladder cancer in men: when comparing unexposed (≤ 5 µg/l to exposed (> 5 µg/l) men, the effect size was higher in North American studies than in European studies, but the difference was not statistically significant (95% CI -0.22 to 0.31).

Therefore there is no need to integrate any European specificity into risk-assessment analysis in Europe in relation to THM exposure and bladder cancer. The exposure-risk relationship estimated from the global meta-analysis including a large population (4351 cases, 7055 controls) from North America and Europe can therefore be used in future risk/burden of disease calculations.

Fluoridation Water consumption beliefs and practices in a rural Latino community: Implications for fluoridation.

Scherzer, T., Barker, J.C., Pollick, H. and Weintraub, J.A. (2010) Journal of Public Health Dentistry, 70(4); 337-343.

Adequate fluoride exposure is especially important in communities with a disproportionately high prevalence of dental caries such as rural Latino farm workers and their children. In the US population served by public water supplies, community water fluoridation has reached about 70%. There are however multiple barriers to adequate fluoride exposure including community perceptions of water quality and how these perceptions influence water consumption. In the last decade in the US there has

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been a notable increase in bottled water usage and tap water avoidance and this is particularly apparent among urban Latinos. This study was undertaken to explore the relationships between rural Latinos’ perceptions of water quality and their water consumption decisions, and the implications of these for adequate fluoride exposure The study was undertaken in the Central Valley, California.

California has a high proportion of Latino migrant and nonmigrant farm workers in the population and Central Valley is representative of other rural communities in the region. The tap water supply for the Central Valley community contains naturally occurring fluoride at levels averaging 0.6 ppm. This is slightly below the optimal range (0.7-1.2ppm) for caries prevention. There are several freestanding selfservice filtered water outlets (water mills) in the community that provide water at a cost of $US 1.00 per gallon.

Focus groups and in-depth qualitative interviews were conducted with adults who were Latino and a parent or primary caregiver to a child aged 1-5 years.

Each focus group session or interview lasted between 1.5 and 2 h and was audio-taped. The semi-structured interviews included topic areas and questions derived from the literature and prior work. Major questions included beliefs about tap water quality and other local water sources, beliefs about water safety and water consumption practices, including water use for drinking, infant formula mixture and cooking. Other questions included beverage preferences and consumption; knowledge of and beliefs regarding fluoride including its benefits and the relationship between fluoride, water consumption and oral health; and acceptability of water-based fluoride delivery mechanisms such as fluoride drops /tablets, fluoridation of filtered water stations, or fluoridated bottled water purchase at additional expense.

Participants were asked to complete a brief questionnaire including: socio-demographic characteristics, an evaluation of their overall health and oral health status and their children, and their water consumption practices.

There were 46 individuals who participated in the study. There were four focus groups each with five to six participants and 22 individual interviews were

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conducted. Participants predominantly had low educational attainment and low-income and were mostly farm workers. Most of the residents who participated in the study did not drink the municipal water and felt strongly that it was unsafe to drink unfiltered tap water on the basis of taste, appearance and smell. Respondents claimed that the water caused stomach aches, nausea and vomiting in adults and children, who consumed it unfiltered, as well as skin irritation or lesions and hair loss. Participants also claimed that the tap water corroded the plumbing pipes in their homes and their air conditioning systems. There were only a small minority (primarily city officials) who stated that the municipal water was safe to drink and had substantially improved in quality since 2002 when the city government upgraded the water system. Most of those who participated in the study indicated that they were unaware of the existence of, or the content of, the annual water quality report produced by the city government. Many residents said they would be convinced of the water’s safety if they saw evidence of water tests from a reputable source.

Most participants consumed bottled water, homefiltered water or water purchased in bulk from the water mills at home. Children at home mostly consumed bottled water. When not at home, participants and their children mainly drank bottled water, however for cooking, about half the participants used tap water as they considered it would be rendered safe. Most participants believed that water is the healthiest beverage, especially for children, however they regularly drank tap water alternatives such as soda, fruit juice or flavoured water if filtered or bottled water was not available.

Most participants had little knowledge about fluoride or the reason for fluoride exposure. Most participants reported that they used fluoride toothpaste and about one-third said their children had been prescribed fluoride drops, tablets or they had given consent for their children’s teeth to have fluoride varnish applied.

Most study participants said they would be willing to increase their children’s fluoride intake it needed, but several participants said that the use of fluoride drops or tablets would be problematic. People preferred fluoride to be available through a cheap, easily

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accessible, improved municipal water supply rather than other ways. Most respondents said they would be willing to pay a bit more (10 or 20c extra) for fluoridated water from the water mill or bottled water. Participants stated that if tap water improved there would be no reason to purchase water alternatives. Most of the participants said they would be more inclined to drink tap water if it were fluoridated however at least half emphasised that they would only drink fluoridated tap water if it tasted, looked and smelled better and didn’t make people sick. It was commonly stated that only if tap water was demonstrated to be safe would consumption increase, regardless of whether it was fluoridated or not.

This study shows the ways in which people’s beliefs and perceptions shape their water consumption behaviours, and indicates issues and implications for fluoride exposure and oral health that extend beyond the study population or local study site. The taste, colour or odour of the water supply are secondary in terms of ensuring safety but are primary in terms of establishing its acceptability and consumption by the population served by it. In vulnerable populations such as in this study, abstract, technical reports of water safety not only need to be believed and trusted but also matched or superseded by experience before any meaningful change will occur in .water consumption behaviour.

Iodine Is Gippsland environmentally iodine deficient?

Water iodine concentrations in the Gippsland region of Victoria, Australia.

Rahman, A., Deacon, N., Panther, B., Chesters, J. and Savige, G. (2010) Australian Journal of Rural Health, 18(6); 223-229.

Iodine is an essential micronutrient which plays a vital role in the normal development of most organs including the brain. Iodine deficiency is the single greatest cause of preventable brain damage and developmental delay in the world and can account for a loss of 10-15 IQ points even with moderate deficiency. In 2003-2004, the Australian National Iodine Nutrition study found that school children in

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Victoria also had the worst iodine deficiency status of all the mainland states of Australia. An Australiawide iodine supplementation program was subsequently initiated via bread products. The mean iodine concentration of tap water was calculated by the 22nd Australian Total Diet Study (ATGS) to be 11.3 µg L-1. Food Standards Australia and New Zealand (FSANZ) estimate that the Australian population would receive 5-9% of its total dietary iodine supply from drinking water. The concentration of iodine in water can be used as a surrogate marker for iodine deficiency in a population as it affects not only the direct iodine intake from water but also the iodine content of food produced and consumed in the region supporting the population. The cut-off value for water iodine concentrations which is considered to be indicative of environmental deficiency is <2 µg L-1. The Gippsland region of Victoria has a long history of iodine deficiency. This study aims to examine the iodine concentration of drinking water across the Gippsland region and to investigate the potential contribution of iodine from water to the Gippsland diet. Also the iodine concentration of drinking water in sources close to the sea was investigated to determine if these sources have a higher concentration of iodine than drinking water obtained further inland.

Water samples were collected from 18 water treatment plants across the central, west and southern regions of Gippsland. Water samples were collected from both untreated and treated water (suitable for drinking). Samples were also collected from four household rain water tanks from outlet taps.

The concentration of iodine in the water samples from the treatment plants in the Gippsland region ranged from 0.10 to 1.26 µg L-1 for untreated water and 0.11 to 1.07 µg L-1 for treated water. The mean iodine concentration of untreated water was 0.4 µg L1 and for treated water 0.38 µg L-1 . The mean difference in iodine concentration of untreated and treated water from the same treatment plant was not statistically significant. For the rain water tank samples, the water iodine concentration ranged from 0.1 to 0.36 µg L-1 and the mean iodine concentration was 0.24 µg L-1. All of the water samples had iodine values that were well below the cut-off value (2.0 µg L-1) which indicates environmental iodine deficiency.

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It is estimated by the WHO that the average daily drinking water requirements for younger children and adults is one and two litres, respectively. These amounts were used to estimate the intake of iodine from drinking water in Gippsland. Infants would only consume 0.38 µg of iodine (< 1% of the recommended daily intake of iodine for this group) and adults would only consume 0.76 µg of iodine (< 1% of the recommended daily intake of iodine).

Therefore the amount of dietary iodine obtained from drinking water in Gippsland falls well below the estimates of 5-9% suggested by the 22nd ATDS. There was no linear relationship found between water iodine concentration in Gippsland and the distance from the sea.

Drinking water in Gippsland is a very poor dietary source of iodine. The people living in the Gippsland region will be at higher risk of dietary iodine deficiency than populations living in other regions not deemed environmental iodine deficient. This increase in risk requires further investigation to ensure iodine deficiency is adequately addressed by the mandatory bread fortification program in these areas. If this is not the case then a more targeted approach is needed that may include iodine supplementation especially among those groups at most risk of deficiency such as pregnant and lactating women and their infants. The assumption that the Australian population receives between 5 and 9% of the recommended daily intake of iodine through drinking water is not true for all regions and needs to be amended to allow for this regional variation in the concentration of this dietary component.

Comment It has been long known that Australian and New Zealand soils are relatively deficient in iodine, resulting in low iodine levels in locally produced vegetables, grains and meat. Intake of iodine from foodstuffs has fallen in recent decades due to discontinuation of iodine-based disinfectants in the dairy industry, and increasing consumption of processed and packaged foods which are generally prepared with non-iodised salt. Iodine fortification of bread was introduced in late 2009 in both Australia and New Zealand to reduce the incidence of iodine deficiency in the population.

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Legionella Contamination of the cold water distribution system of health care facilities by Legionella pneumophila: Do we know the true dimension?

Arvand, M., Jungkind, K. and Hack, A. (2011) Eurosurveillance, 16(16): Article 3, 6p.

Legionnaires’ disease (LD) is an important cause of hospital-acquired pneumonia. In the early 1980s, potable water was recognised as the major environmental source of healthcare-associated LD (hca-LD). In Germany, the water guidelines do not recommend routine assessment of cold water for Legionella contamination, except if the water temperature at distal sites exceeds 25 °C. The results of an evaluation of the water distribution system (WDS) of four healthcare facilities for Legionella contamination in Hesse, Germany are presented in this paper. Two cases of hca-LD were diagnosed in one facility, an acute care hospital specialised in thoracic surgery and a solid organ transplantation unit. Moderate to high Legionella contamination had been detected in the other facilities which included two nursing homes and a rehabilitation centre with cardiologic, orthopaedic and psychosomatic departments. A multidisciplinary team visited each facility to determine the extent of the contamination of the WDS, to assess the contamination of cold and warm WDS independently and to investigate a possible correlation between the water temperature at sampling time and the extent of Legionella contamination.

Each of the four facilities was visited between four to six times between March 2009 and August 2010 by a team of specialists of the Communal Health Office and the Hesse State Health Office (HSHO). There were 59 water samples taken from central lines (cold and hot-water tanks, return lines) of all facilities.

There were 625 samples taken from distal sites (467 showerheads, 155 taps, one pond and two spring fountains) of the facilities. Cold and warm water samples were generally sampled in parallel at distal sites. When samples were taken the temperature of the water was documented. Samples of approximately 200 ml were collected at central sites after 3 L of cold or 3 L of warm water was discarded

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and at distal sites after 3 L of cold or 5 L of warm water was discarded. Legionella culture was performed on GVPC agar according to the Federal Environmental Agency recommendations. Serotyping was performed to identify Legionella species and serogroups.

The 59 samples collected at central lines included 28 warm (temperature range: 46-75 °C) and 31 cold (temperature range: 7-14 °C) water samples. Of these central samples, 10 were contaminated with Legionella including nine warm and one cold water sample. Of the 625 distal water samples collected there were 309 warm (temperature range: 32-70 °C) and 316 cold (temperature range: 7-29 °C). Of these distal samples, 197 were contaminated with Legionella including 125 cold water samples and 72 warm water samples. The overall contamination rate of distal water samples was 41%, 81%, 29% and 27% in the four facilities. The contamination rate of cold and warm water in facilities A, B, C and D were 25% versus 60%, 88% versus 73%, 39 versus 19% and 28 versus 25%, respectively. L. pneumophila serogroup 1 was isolated in facility A, C, and D, L pneumophila serogroup 2-14 in facility B and non-pneumophila Legionella spp. in facility A and C. L. pneumophila serogroup 1 was also isolated from the bronchoalveolar lavage fluid of the index patient with hca-LD in facility C. Cold water samples were more frequently contaminated with higher Legionella concentrations in comparison to warm water samples.

The difference between cold and warm water was significant in all concentration categories except for minimal contamination. Cold water samples were more frequently contaminated with high Legionella concentrations, ie. ≥ 1,000 cfu/100 ml, than warm water samples in three of the four facilities.

Legionella concentrations of up to 10,000 cfu/100ml were found in distal cold water samples. The relationship between the temperature of the distal water at sampling time and Legionella contamination was examined. Outside the preferred temperature range of Legionella growth (25°C to 45°C), there was significantly less contamination in warm water than in cold water (p<0.001).

This study showed that the cold water supply of healthcare facilities may be even more heavily

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contaminated by Legionella species than the warm water supply. Different factors may have contributed to this interesting finding. It is possible that a thermal disinfection of warm WDS was performed shortly before the samples were taken (in response to the occurrence of LD cases or detection of elevated levels in routine screening tests). Another possibility is that a “warming-up” of cold water, may have occurred after a long interval of stasis or when the cold and warm water pipes are closely fitted in the same shaft and run together over a long distance without proper insulation. There was no reliable correlation found between cold water temperature at sampling time and Legionella contamination rate or concentration. This may be because the temperature at sampling time, which is usually a busy time on a working day, is not representative of the temperatures that the sampled water has undergone before the sampling. These results highlight the importance of assessing the cold water supply of healthcare facilities for Legionella when an intensified analysis is performed.

Microbial Risk Assessment Risk-based evaluation of Escherichia coli monitoring data from undisinfected drinking water.

Soller, J., Embrey, M., Tuhela, L., Ichida, A. and Rosen, J. (2010) Journal of Environmental Management, 91(11); 2329-2335.

The U.S. Environmental Protection Agency (EPA) developed the Total Coliform Rule (TCR) in 1989. In this rule the presence of total coliforms was stated to be the best available indication of water contamination of concern to human health. The TCR requires drinking water systems to monitor for total coliform in distribution systems and identify possible contamination in finished drinking water. If there is a positive total coliform result, an additional test is required to assess if the positive coliform is Escherichia coli. E. coli is considered an indicator of faecal contamination when found in drinking water.

There are however other thermotolerant genera which are widely distributed in the environment that may also trigger a positive total coliform result but may not be related to faecal contamination or to human

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health risks. The USEPA is revising this original TCR and it may focus on using total coliforms as a trigger for action and using E. coli as the maximum contaminant level organism because of its more direct significance for public health. This potential change is based on the fact that real illnesses are related to the presence of human pathogens, which E. coli might better predict than the broader group of total coliform bacteria. In the United States there are an estimated approximately 73,500 E. coli 0157:H7 illnesses annually from all causes. This study evaluated the potential relationships between the presence of generic E. coli strains in drinking water and E. coli 0157:H7 using a disease transmission model to investigate the potential health implications of a positive E. coli result from routine TCR monitoring.

A previously published disease transmission model for E. coli 0157:H7 was modified to include risks from drinking water and dose-response relationships were updated. The model was then calibrated so that it predicted E. coli 0157:H7 illness levels that were consistent with CDCs estimation of 73,500 E. coli 0157:H7 illnesses per year in the United States. Next, feasible levels of E. coli 0157:H7 were identified in drinking water and the possible relationship between the number of positive E. coli samples and E. coli 0157:H7 organisms was investigated. The model was comprised of five state variables that are used to track the epidemiological status of individuals with respect to exposure infection, symptoms, infectiousness and immunity over time. Individuals are assumed to be exposed to E. coli 0157:H7 via primary sources (food, drinking water, unknown sources) and secondary (person-to-person) transmission. The model included the following health-based parameters for E. coli 0157:H7: the incubation period; the proportion of infections that result in a symptomatic response; the duration of the infection (both symptomatic and asymptomatic); and the duration of immunity.

The base analysis included 20.2 million individuals in the US who receive water from community water systems that do not disinfect, and the sensitivity analysis considers three different population sizes: 4.6, 30.1 and 70.1 million individuals. The model

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was calibrated using 5000 simulations, each of which represented a 1000-day period. The results of the calibration simulations indicated that the simulations below the 6th percentile or above the 68th percentile were not credible. Once calibrated, the model was used to estimate the proportion of those E. coli 0157:H7 illnesses that could feasibly be due to drinking water. The base analysis model was run using estimates for the lower (1%), median (15%) and upper (35%) feasible range for the drinking water-attributable fraction of E. coli 0157:H7 illnesses. The model was rerun to find E. coli 0157:H7 levels in drinking water that were associated with median incidence levels that corresponded to the attributable illness levels of interest (705, 10,600, and 24,700) for the at-risk population of 20.2 million people. A final set of simulations were conducted to determine the feasible relationships between positive E. coli observations (under routine TCR monitoring) and E. coli 0157:H7 organisms in drinking water.

The feasible range of illnesses attributable to drinking water varies from 90 to 44,000 illnesses per year. The median estimate for the number of illnesses attributable to drinking water is 10,600, with a feasible range of 705-24,700. The estimated median levels of E. coli 0157:H7 in undisinfected groundwater ranges from 2.8 x 10-5 â&#x20AC;&#x201C; 9.8 x 10-4 organisms per litre with a point estimate of 4.2 x 10-4 organisms per litre, assuming that E. coli 0157:H7 illnesses in drinking water came only from the population drinking groundwater from undisinfected public water systems (20.2 million individuals). The estimated median level of E. coli 0157:H7 in drinking water decreases as the size of the at-risk population increases (and vice versa). If the size of the at-risk population is 70.1 million, the model predicts a point estimate of 1.2 x 10-4 E. coli 0157:H7 organisms per litre of drinking water for those individuals. If the size of the at-risk population is 4.6 million, the model predicts a point estimate of 1.9 x 10-3 E. coli 0157:H7 organisms per litre of drinking water. The feasible ratios between positive E. coli observations and E. coli 0157:H7 organisms increased with the size of the at-risk population. For an at-risk population of 20.2 million, on average, 25 positive TCR E. coli samples (range 11-400) would be expected to include one E. coli 0157:H7 organism

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(this does not imply that an infection occurs).

However for an at-risk population of 70.1 million, on average 90 positive TCR E. coli samples (range 391300) would be expected to include one E. coli 0157:H7 organism. Therefore, depending on the size of the at-risk population, the estimated feasible relationship between indicator E. coli positives and E. coli 0157:H7 organisms varies at a minimum of 6:1 (range 2:1-100:1) for an at-risk population of 4.6 million to a maximum of 90:1 (range 39:1-1300:1) for an at-risk population of 70.1 million.

The median estimates for the number of E. coli 0157:H7 illnesses attributable to drinking water in the United States using the model were found to be similar to the CDCâ&#x20AC;&#x2122;s estimation of E. coli 0157:H7 illness in the United States. The size of the at-risk population has a strong influence on the modelâ&#x20AC;&#x2122;s predictions for E. coli 0157:H7 in undisinfected or inadequately disinfected drinking water. The relationships between bacterial indicator E. coli positives and E. coli 0157:H7 organisms depend on the size of the at-risk population. The recently enacted U.S. EPA Ground Water Rule will likely reduce the use of undisinfected groundwater, which in turn will cause a decrease in E. coli 0157:H7 illnesses from undisinfected groundwater. The results here provide a framework for considering the potential public health implications of a positive E. coli result from routine TCR monitoring as it relates to E. coli 0157:H7 in drinking water.

Comment The authors base their estimate of the 15% of infections feasibly due to drinking water on a study of E. coli O157 outbreaks, however the relative importance of different infection sources in recognised outbreaks may not necessarily reflect the causes of unrecognised outbreaks and sporadic case which probably make up the majority of infections.

Norovirus Norovirus Outbreak Caused by a New Septic System in a Dolomite Aquifer.

Borchardt, M.A., Bradbury, K.R., Alexander, E.C., Kolberg, R.J., Alexander, S.C., Archer, J.R., Braatz, L.A., Forest, B.M., Green, J.A. and Spencer, S.K. (2011) Ground Water, 49(1); 85-97.

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Norovirus infection is the cause of approximately 50% of all gastroenteritis outbreaks worldwide.

Consumption of faecal-contaminated groundwater has resulted in several norovirus outbreaks, although in many of these the source of contamination was never identified. This paper reports investigation of a large norovirus outbreak at a newly opened restaurant in Wisconsin, US. The premises had a private well located in a fractured dolomite rock aquifer. Water supply wells in fractured rock and karst settings are particularly vulnerable to contamination from surface sources as groundwater flow rates in such settings can be very rapid and attenuation of contaminants is often minimal. This study demonstrates the combined use of epidemiological, microbiological and hydrogeological methods to investigate the outbreak.

On June 1, 2007, the Door County Public Health Department (DCPHD) in Wisconsin received a report of four cases of acute gastroenteritis among employees at a large new restaurant. The private well and septic system were newly constricted and conformed to Wisconsin State Code. Cases of acute gastrointestinal illness were defined as individuals who experienced diarrhoea or vomiting within 2 to 5 days after consuming food or beverages at the restaurant between the opening date on May 10 and the last day of service before voluntarily closing on May 31. Controls were family members or friends of cases who visited the restaurant on the same dates but were not ill. Interviews were conducted by DCPHD nurses using a standardised outbreak questionnaire.

Stool specimens were requested from symptomatic cases and analysed for enteric pathogens.

Tap water samples were collected from the restaurant and nearby homes. Samples were analysed for coliforms, Escherichia coli bacteria and human enteric viruses. Quantitative polymerase chain reaction (qPCR) was performed for six groups of human enteric viruses: adenovirus, enterovirus, hepatitis A, norovirus genogroup I (GI) and genogroup II, and rotavirus. A natural-gradient tracing experiment was conducted using fluorescent dyes injected at two points in the septic system to evaluate potential subsurface connections and travel times from the restaurant septic system to the restaurant well and several local domestic wells.

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There were 211 patrons and 18 food workers that met the case definition. Also there were 15 probable cases and 8 secondary cases. Six primary cases and one secondary case were hospitalised. There were 18 stool specimens analysed for enteric pathogens, 4 were positive for norovirus, 1 was positive for Campylobacter spp., and 1 was positive for Salmonella enterica subspecies enterica. Odds ratios were calculated for 45 restaurant menu items.

Drinking water, ice and house salad washed at the restaurant were all associated with illness.

Consuming steak was the only food risk associated with illness that did not have a clear connection with the restaurantâ&#x20AC;&#x2122;s water. During the outbreak investigation the restaurant well water was sampled on eight dates. Seven water samples collected on June 5 and 6 from various restaurant taps (kitchen, basement, and outdoor) were all positive for coliform and E. coli bacteria; three samples collected on the latter date were positive for norovirus GI at an average concentration of 50 genomic copies per litre.

On June 15, ultraviolet (UV) disinfection was installed on the restaurantâ&#x20AC;&#x2122;s main water line from the well. All subsequent bacterial indicator samples collected immediately downstream of the UV unit were negative, however raw well water samples were still positive for coliform through July and until the end of October. On June 28, a second round of virus sampling took place and norovirus GI was still present in the raw well water, in the clarified septic effluent just before the septic infiltration field and in a UV-treated sample. Norovirus sequencing indentified the genotype as GI.2 and showed the identical virus was present in restaurant tap water, patronâ&#x20AC;&#x2122;s stool specimens and in the septic tank. None of the private wells samples were positive for norovirus GI, suggesting that the virus source was restricted to the restaurant site. The investigators concluded the virus was introduced to the septic system when an employee suffered several episodes of vomiting and diarrhea while at work in late May. The restaurant well was 85.3 m deep and cased to 51.8 m. It was located 188m from the septic leach field. Tracer tests using dyes injected in the septic system showed that effluent was travelling from both the septic tanks and infiltration field to the well in 6 and 15 days, respectively. The rapid arrival of the

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dye in the well shows that in a highly vulnerable hydrogeological setting such that as found here, compliance of septic systems with regulations may not give adequate protection from faecal pathogens.

When the outbreak was first reported, the newly constructed septic system was thought to be an unlikely source. However the interdisciplinary investigation was able to demonstrate the cause of the outbreak by using a combination of epidemiological, microbiological and hydrogeological methods. The construction of conventional septic systems above vulnerable fractured limestone aquifers, particularly for facilities like restaurants that generate a large volume of waste water, needs to be re-examined if public health is to be protected adequately.

POU Treatment Field assessment of a novel household-based water filtration device: a randomised, placebocontrolled trial in the Democratic Republic of Congo Boisson, S., Kiyombo, M., Sthreshley, L., Tumba, S., Makambo, J. and Clasen, T. (2010) PloS ONE, 5(9) doi10.1371/journal.pone.0012613 Treating water at the household or other point of consumption is a means by which vulnerable populations can improve the quality of their drinking water and prevent diarrhoeal diseases. Current methods of treating water at home have been found to have certain shortcoming and there is evidence that placebo effect and reporting bias play a role in the estimate of effect reported in some trials. This randomised, double-blinded, placebo-controlled trial was undertaken in rural Democratic Republic of Congo (DRC) to assess the field performance, use and effectiveness of a novel filtration device in preventing diarrhoea. The study was conducted from April 2008 to July 2009 in the rural health zone of Bibanga in the eastern province of Kasai, DRC. Over three quarters of the population in rural areas in DRC rely on unimproved water sources for drinking, mostly surface water and unprotected springs. Each of the intervention households received a Lifestraw Family filter and each control household received a placebo. The Lifestraw Family is a newly developed household-based gravity-fed microbiological water

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purifier that employs hollow-fibre membranes to remove waterborne pathogens by ultrafiltration.

Water is pored into a 2.5 L plastic vessel, passes through a 27-µm prefilter and flows down a 1 m long plastic pipe before passing through the hollow-fibre filtration cartridge. The top vessel of the filter contains a slow eluting chlorine tablet to prevent biofilm formation and increase the life of the hollowfibre cartridge. Treated water is accessed from the side of the cartridge via a tap. The device is cleaned daily by rinsing the prefilter and backwashing the cartridge using a squeeze-pump and outlet valve mounted on the bottom of the cartridge. Laboratory tests showed the device met the USEPA standards of microbiological water purifiers by reducing bacteria by 6.9 logs, viruses by 4.7 logs and protozoan cysts by 3.6 logs. The placebo appeared the same as the Lifestraw Family except that the chlorine tablet was removed from the upper vessel, the filtration membranes were replaced by some extra piping and the 27-µm screen on the pre-filter was removed.

A baseline survey was undertaken in April 2008 to collect information on demographics, socioeconomic characteristics and water, hygiene and sanitation practices. Following the baseline survey, households were randomly assigned into either the intervention or placebo group. Households were trained on use and maintenance of the device and advised to drink filtered water directly from the tap and not to store filtered water to prevent recontamination. The allocation of filters was concealed from both field investigators and the study population. The outcomes assessed included diarrhoea, filter monitoring, water quality, compliance and blinding. Investigators interviewed the female head of the household or primary care giver of young children once each month for 12 months. They recorded any diarrhoea cases in the preceding seven days. Each month, a random sample of 30 filters and 30 placebos was monitored. At each household visit, field workers took note of the location and condition of the filter and recorded if the respondent was able to use and clean the filter correctly. Flow rate was monitored and samples of influent and effluent water were collected from each of the selected devices. If the water was stored once filtered, a third sample of stored water was taken. All

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water samples were tested for thermotolerant coliforms (TTC) within 4 h after collection. Eight and fourteen months after filter distribution, a crosssectional survey was conducted in each household and participants were classified as current users if they reported using the filter ‘today or yesterday’ and if the filter was hung for use with water in the top vessel of the device. Consistency of use was estimated by asking the respondent if they had drunk unfiltered water within the previous day. The survey also covered further aspects of use and acceptability.

Immediately after the end of the follow-up period, the effectiveness of blinding was assessed by questioning female heads or primary care givers.

There were 240 households enrolled in the study; 120 were assigned to receive the Lifestraw Family filter and 120 the placebo. Data was collected for 11,236 (81.8%) possible person-weeks of observation over the 12 months of follow-up. Over the study period there were 12 deaths in the intervention group and 8 in the control group. The invention and control groups were found to be similar in terms of demographic and socio-economic characteristics and hygiene and sanitation practices. Only four of the households reported treating their water sometimes or rarely by boiling or adding bleach. Only 37% of households had a latrine and 51% had soap present in the house at the time of visit.

At baseline, the prevalence of diarrhoea was similar in both groups (12.6% versus 10.6% for control and intervention groups, respectively). Over the 12 month follow-up, participants who had the active filter had 15% fever weeks with diarrhoea compared to those who received a placebo (mean, 2.66 versus 3.15, respectively). The longitudinal prevalence ratio (LPR) adjusted for clustering within the household was 0.85, however the confidence interval was wide and included 1 (CI 0.61; 1.20). The longitudinal prevalence ratio among children under five was 0.85 (95% CI 0.56; 1.28). Each of the devices was tested on average 3 times during follow-up. Source water was highly contaminated with 75% of household sampling showing contamination levels about 1000 TTC/100ml. The active filter was found to achieve a log reduction value (LRV) of 2.98 (95% CI 2.88, 3.08), removing about 99.8% of indicator bacteria.

There were overall, 64% of water samples treated

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with the filter that were free of TTC and 27% had TTC levels between 1-10 TTC/100 ml. None of the filters produced water with >100 TTC/100ml consistently over the three visits. There were 73% of water samples from the placebos that contained between 100-1000 TTC/100 ml. The placebo was found to actually remove more than 90% of TTB from source water (LRV 1.05. 95% CI: 0.93, 1.16).

The filter was found to have a mean flow rate of 202 ml/min and it declined slightly over time.

There were 56% of respondents that correctly demonstrated how to clean the filters. Overall, 36 (12.4%) of the 290 active filters were found to be damaged during visits, mainly due to rodents chewing on the soft hoses (n=35). Eight months after distribution 183 (75%) of the households were present at the visit and were still in possession of their filter. In the intervention group, 68% of respondents could be defined as current users versus 48% in the placebo group (p<0.001). However, nearly all adults (83%) and young children (95%) reported drinking untreated water in the previous day.

Fourteen months after distribution, the proportion of current users was slightly higher in both groups (76% in the intervention group, 69% in the control group).

The blinding of the intervention was not successful with the vast majority of survey respondents in the intervention group believing they had received the active filter. However a large proportion of control household remained blinded throughout the trail.

This study provided little evidence of a protective effect of the filter against diarrhoea with wide confidence intervals giving little statistical support.

The sample size in this study was not sufficiently large to detect a statistically significant difference in diarrhoea of 15%. The baseline prevalence of diarrhoea was also lower than anticipated and the clustering effect due to repeated measurement and household randomisation was higher. Further studies are required with sufficient power to detect if any effects are due to the filter. This study also shows that there is a need to monitor placebo performance with the placebo device also removed faecal bacteria when this was not intended. The study highlights the challenges of blinding household-based water treatment interventions under adverse conditions.

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Supply Interruption Community health impact of extended loss of water service - Alabama, January 2010.

Etheridge B, Porter T, Holliday et al. (2011) Morbidity and Mortality Weekly Report, 60(6); 161166.

During January 2010, approximately 18,000 residents of two communities in Alabama lost access to municipal water after sub-zero overnight temperatures caused many utility water mains and residential water pipes to break. Water utilities were forced to cut off service to most households in the two communities due to the systemic water loss and related mechanical failures. Community A and community B are located in southwestern Alabama in two contiguous, predominately rural counties and are served primarily by three interconnected public water utilities. When the Alabama Department of Public Health (ADPH) learned about the water problems, a boil water advisory was issued to both communities and arrangements were made to deliver bottled water and on-site filtration/UV disinfection units.

A household survey was conducted between February 26 and March 9, 2010 to assess the extent of the water emergency and its effect on public health. A random sample of addresses was drawn from community A, community B and two other communities in the same area that were presumed to be unaffected by the water emergency. Interviews were conducted with one adult in each home and questions were answered regarding normal household water service and January water service interruptions, including loss of service, loss of pressure and availability and use of emerging water sources. Each respondent also provided information on every household member which included demographics, chronic health conditions and whether or not household members had experienced acute illness during January 4-31, 2010. The main outcomes of interest were acute gastrointestinal illness (AGI) and acute respiratory illness (ARI). Data were also collected on skin and eye complaints. A total of 470 of the 610 eligible households completed the survey, providing data for 1,283 people. Of the households with no loss of water service or pressure, AGI was

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reported for 13 (4.3%) of residents during January 431. Higher rates of AGI were seen in households which had experienced loss of service and/or loss of pressure. AGI was found to be associated with a combined loss of water service and pressure (67 residents [12.4%], adjusted odds ratio (AOR) = 2.6), loss of service≥ 7 days (46 [13.2%], AOR = 2.4), and loss of pressure≥ 7 days (23 [15.6%], AOR = 3.5) and 3-6 days (30 [12.7%], AOR = 2.8). Doseresponse relationships were apparent for the duration of both loss of service and loss of pressure (p for trend = 0.03 and 0.002, respectively).

Among the unaffected households the prevalence of ARI was 13.9%. Individual AORs were not statistically significant, however reporting of ARI increased with increasing duration of loss of pressure (1-2 days, 12.8%, 3-6 days, 20.5%, ≥ 7 days, 22.8%; p-value for trend = 0.04). Loss of water service was not found to be associated with ARI. Of the 470 households surveyed, 108 (23%) had experienced water pipe breaks. Only 210 (45%) households had any water stored for emergencies and less than 10% had stored > 5 gallons. Of those households which were under a boil water advisory, 90% of residents had heard about the advisory, but fewer than 50%

heard about it at the beginning of the water emergency and 30% reported drinking unboiled tap water. A qualitative investigation was concurrently conducted which included focus group discussions with members of the community, emergency responders and government officials along with interviews with key informants from institutions (e.g., restaurants, schools and health-care facilities).

In general it was found that community emergency preparedness planning had not included collaboration with water utilities, plans had not outlined a clear command structure and boil water notification procedures and emergency water distribution did not meet the requirements of vulnerable populations such as senior citizens and those with disabilities or limited financial or transportation resources. As a result of this investigation the CDC prepared recommendations for public health agency involvement in water emergency preparedness.

Disclaimer Whilst every effort is made to reliably report the data and comments from the journal articles reviewed, no responsibility is taken for the accuracy of articles appearing in Health Stream, and readers are advised to refer to the original papers for full details of the research.

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Health Stream is the quarterly newsletter of Water Quality Research Australia. Health Stream provides information on topical issues in health research which are of particular relevance to the water industry, news and updates on the recent literature. This newsletter is available free of charge to the water industry, public health professionals and others with an interest in water quality issues. An electronic version of the newsletter and a searchable archive of Health Stream articles are available via the WQRA Web page. Summaries of Web-bonus articles are available only in the electronic version.

To be placed on the print mailing list for Health Stream please send your postal address details to: Pam Hayes Epidemiology and Preventive Medicine Monash University - SPHPM Alfred Hospital, Melbourne VIC 3004 AUSTRALIA

Phone +61 (0)3 9903 0571 Fax +61 (0)3 9903 0556 Email pam.hayes@monash.edu

To be placed on the email notification list for Health Stream, please email your request to: pam.hayes@monash.edu © Copyright WQRA. Health Stream articles may be reproduced and communicated to third parties provided WQRA is acknowledged as the source. Literature summaries are derived in part from copyright material by a range of publishers.

Original sources should be consulted and acknowledged.

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Health Stream 62- June 2011Web Bonus articles Arsenic The association between arsenic exposure from drinking water and cerebrovascular disease mortality in Taiwan.

Cheng, T.J., Ke, D.S. and Guo, H.R. (2010) Water Research, 44(19); 5770-5776.

Chronic arsenic intoxication is common on the southwestern coast of Taiwan due to the high arsenic levels in ground water. This area is called the blackfoot disease endemic area (BFDEA) as residents are at risk of this occlusive peripheral artery disease which leads to progressive gangrene. A higher prevalence of cardiovascular disease in this area has been reported. Dose-response relationships between chronic arsenic exposure and peripheral and cardiovascular diseases in the BFDEA in Taiwan have been found, however such a relationship has not been established for cerebrovascular disease (CVD).

Increased prevalence of CVD has been found in the Lan-Yang Basin (LYB) in the northeast of Taiwan where the underground water is also contaminated with arsenic. Also, some ecological studies have suggested exposure to low-to-moderate levels of arsenic in drinking water is associated with increased mortality rates for CVD in men and women. As previous studies have reported inconsistent results regarding the association between chronic arsenic exposure and CVD, a study was conducted in Taiwan with the aim of clarifying this association.

The number of CVD deaths from 1971 to 2005 was identified from the Taiwan death registry. The study was limited to people over 35 years of age, as deaths in younger people might not involve chronic and acquired health effects of arsenic exposure.

Residents of the BFDEA which spans parts of ChiaYi and Tainan counties along with those of the LanYang Basin, comprised the two populations with chronic arsenic exposure. These populations were compared to two reference populations, the national population and the population of the Chia-Yi and Tainan Counties combined (CNC).

A survey of arsenic in water from artesian wells in the BFDEA found levels ranging from 0.01 to 1.80 ppm (mg/L), with a mean of 0.50 ppm, and about half of the samples were found to be between 0.40 and 0.70 ppm. A survey of arsenic levels in well water in nine villages surrounding the BFDEA found levels ranging from 0.001 to 0.017 ppm only. In the Lan-Yang Basin (LYB) a study found arsenic levels in ground water that ranged from undetectable (<0.00015 mg/L) to 3.59 mg/L. HEALTH STREAM

Direct standardised mortality rates were calculated using the population of Taiwan in mid-1988 as the standard population.

Gender-specific indirect standardised mortality ratios (SMR) were calculated for the four populations. As the number of deaths in the areas with arsenic exposure was relatively small in each year, the 3-year moving average of the SMR were calculated and the 35-year cumulative sum was calculated to minimise the instability.

The mortality rate was found to increase with age, and men had higher rates of CVD than women. The direct standardised mortality rate of CVD in Taiwan steadily declined from 2.46/1000 person-year (1.39/1000 person-year in men and 1.06/1000 personyear in women) in 1971 to 0.63/1000 person-year (0.38/1000 person-year in men and 0.25/1000 personyear in women) in 2005. A trend was also found of decreasing direct standardised mortality rate of CVD in both genders in the other three areas in the study period. Differences between men and women were further evaluated by comparing the SMRs over the 35-year period in each of the four populations and women were found to generally have lower CVD mortality than men. To evaluate the association between arsenic exposure from drinking water and CVD, the 35-year cumulative SMRs of CVD in the arsenic exposed populations were compared to those in the reference population in each gender. In both genders, the SMR of CVD was higher in the two populations with arsenic exposure (BFDEA and LYB). When the two exposed populations were compared, the BFDEA had higher risks, with SMR of 1.05 (95% confidence interval [CI]: 1.01-1.10, p < 0.05) in men and SMR of 1.04 in women (95% CI: 1.00-1.09, p=0.05).

CVD mortality in Taiwan had steadily decreased in men and women since 1971 until 2005. Chronic arsenic exposure from drinking water was however associated with increased risks of CVD with women having in general a lower CVD mortality than men.

CVD was the second leading cause of death during the period 1971-2005 and accounted for tens of thousands of deaths each year. If arsenic can cause CVD, it may contribute to a large number of deaths.

By minimising arsenic exposure from drinking water in endemic areas, CVD may be prevented and controlled as well as many other diseases that are often fatal such as cancer.

Comment The authors note that this study did not look at individual exposure and outcome data, and did not assess other factors such as smoking that are known to be associated with cerebrovascular disease.

Blackfoot disease does not occur in other areas of the world with similar high arsenic levels in drinking

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water, and it has been suggested that other factors, perhaps including nutritional deficiencies, are also involved in causation.

Effects of drinking arsenic contaminated water on spontaneous abortion and neonatal mortality.

Rahamatullah, M., Ara, K.Z.G., Sultana, T. and Jahan, R. (2010) Advances in Environmental Biology, 4(2); 152-154.

This survey examined the association between chronic arsenic exposure and adverse pregnancy outcomes in two different areas in Bangladesh that are highly exposed to arsenic through drinking water and a control area (non-exposed to arsenic). The survey investigated the number of spontaneous abortions and neonatal deaths among women consuming arsenic in their drinking water versus women who are drinking arsenic non-contaminated water.

The exposed group was selected from residents of Gazna (arsenic-exposed area 1, N = 34) and Nikanthapur (arsenic-exposed area 2, N = 47), the comparison group was selected from residents of South Porabari (arsenic non-exposed area, N = 31).

In Gazna and Nilkanthapur 87% of the tubewells used by subjects had arsenic levels above 0.05 mg/L. Mean levels were 0.1578 and 0.1290 mg/L respectively. In South Porabari the arsenic content of the tubewells used was not detectable. The study participants included married women of reproductive age (15-49 years) who had previously had at least one pregnancy. The exposed groups consisted of women who had been drinking arsenic contaminated water (>0.05 mg/L) for at least five years and had signs of arsenicosis. The non-exposed group had been drinking arsenic-free water.

Eligible participants were those women who had been living in the study area since their marriage and had drunk from the respective tube well before and after pregnancy.

All women were interviewed using a semi-structured questionnaire and detailed person to person conversations.

The questionnaire collected information on sociodemographic variables, source of drinking water and use, antenatal care and adverse pregnancy outcomes including spontaneous abortion [failure of pregnancy within the first 28 weeks of gestation] and neonatal death [death of the newborn within 28 days after birth]). Pregnancy outcome events were compared in the exposed and nonexposed areas.

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There were 112 women of reproductive age (15-49 years) interviewed from all three villages. In the arsenic-exposed areas the neonatal mortality rate was highest (20.8% and 24.2%), while it was very low for the non-exposed area (1.3%). There were no reports of spontaneous abortion in the non-exposed area of South Porabari but in the exposed area of Gazna and Nilkanthapur, the observed rates were 13.9% and 11.8%, respectively. The difference in the rate of spontaneous abortion and neonatal mortality was significant (P <0.001) between the exposed and nonexposed areas after adjusting to respondentâ&#x20AC;&#x2122;s other record of diseases.

The arsenic-exposed women in this study had higher rates of neonatal mortality and spontaneous abortion than those women who where not exposed to arsenic, leading to the conclusion that arsenic is the predetermining factor behind the adverse pregnancy outcomes and also a threat to healthy and safe pregnancy outcomes.

Comment This brief paper does not give details of whether other factors such as nutrition or neonatal care impacted on the findings, and some of the numerical aspects of the results are unclear.

Pre-and postnatal arsenic exposure and child development at 18 months of age: A cohort study in rural Bangladesh.

Hamadani, J.D., Grantham-McGregor, S.M., Tofail, F., Nermell, B., Fangstrom, B., Huda, S.N., Yesmin, S., Rahman, M., Vera-Hernandez, M., Arifeen, S.E. and Vahter, M. (2010) International Journal of Epidemiology, 39(5); 1206-1216.

Exposure to arsenic through drinking water has been associated with toxic and carcinogenic effects.

Animal studies have shown arsenic to be a neurotoxin but the data from human studies is scarce.

Recent epidemiological studies in school-aged children have reported associations between cognitive or neurobehavioural function and arsenic exposure through drinking water or industrial pollution. However as these studies were crosssectional, it is not known when these associations developed. During early development the brain is particularly vulnerable to toxic insult and arsenic can easily cross the placenta and may affect foetal neurodevelopment.

A longitudinal study was conducted of the effects of pre- and postnatal arsenic exposure in pregnancy on cognitive, motor and language development at 18 months of age in rural Bangladesh. Concurrent urinary concentrations of arsenic metabolites as markers of exposure and metabolism were assessed.

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The study was undertaken in Matlab, 53 km southeast of Dhaka, Bangladesh. The water used by the pregnant women in this study had a median of 66 µg arsenic/l (10th and 90th percentiles: 1 and 410 µg/l). This study was part of a large communitybased randomised trial (MINIMat) of the effects of food and micronutrient supplementation on pregnancy outcomes and child development. A subsample (n=2853) of the MINIMat cohort, comprising all singleton infants born between May 2002 and December 2003, were selected for developmental assessments at 7 and 18 months of age. Urine samples were collected in early pregnancy, usually in gestation week (GW) 8 and at week 30. Urinary arsenic (U-As) concentrations were measured and the mean of the two measures was used. To assess postnatal exposure, children’s U-As at 18 months of age was measured.

Spot urine samples were collected from mothers in plastic cups and from children in plastic bags placed in potties. Home interviews were conducted to assess socio-economic status (SES). Maternal weight and height were measured at recruitment (about GW 9) and the mothers’ BMI was calculated. Birth weight was measured and length and head circumference. At 18 months of age the child’s weight, height and head circumference were measured again. The children’s heights and weights were converted to standard scores using the WHO growth standards.

Children’s mental and psychomotor development indices (MDI and PDI, respectively) were measured using the Bayles Scales of Infant Development (BSID-II) at 18 months of age. Children were visited in their homes by four interviewers that assessed their language comprehension and expression based on mothers’ report using an inventory based on the MacArthur’s Communicative Development Inventory. Interviewers also assessed the quality of the home environment using the Home Observation for Measurement of Environment (HOME).

There were 2112 (72%) children that had their development assessed at 18 months of age. Of these children, 2009 had data on U-As at 18 months of age.

One child was excluded with extremely high U-As, 1702 children had information on their mothers’ UAs. Maternal U-As was available for 339 of the 741 non-tested children, which was similar to that in mothers of tested children. Median maternal U-As was similar in early (81 µg/l) and late (85 µg/l) gestation and the median of all average U-As in early and late gestation was 96 µg/l. Median child’s U-As was 35 µg/l.

In multiple regressions after adjusting for age, the effect of child’s U-As on language development was

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moderate whereas the effect on Bayley scores was minimal. After adjusting for HOME and other covariates, the arsenic effects on all the developmental outcomes were minimal (all effect sizes for 10 µg/l arsenic ≤ -0.02 z scores). In multiple regressions using maternal U-As, after adjustment for age, arsenic had moderate effects on language tests and less on MDI; however, after adjusting for the covariates, the arsenic effect sizes were negligible in all four regressions (all < -0.04 z scores). Also interactions of arsenic with sex, HOME, assets, child’s weight-for-age z score (WAZ) and height-for-age z score (HAZ) were not significant in the equations. There was no difference in any child development outcome when children in the highest quartile of both pre- and postnatal arsenic exposure were compared with those in the lowest quartile at both times, adjusting for all the confounders assessed.

No effect of arsenic metabolism or nutritional supplementation in pregnancy was found.

No effects of prenatal or postnatal arsenic exposure on children’s development at 18 months of age were found in this study after adjustment for relevant social background factors. However, it is possible that adverse effects depend the duration of arsenic exposure or that only higher cognitive functions that develop later in childhood will be affected. Further follow up on this cohort of children is planned.

Disinfection Byproducts Socioeconomic status and exposure to disinfection by-products in drinking water in Spain Castano-Vinyals, G., Cantor, K.P., Villanueva, C.M., Tardon, A., Garcia-Closas, R., Serra, C., Carrato, A., Malats, N., Rothman, N., Silverman, D. and Kogevinas, M. (2011) Environmental Health: A Global Access Science Source, 10:18.

Some individuals are more likely to be exposed to environmental pollution due to their race, age, ethnicity or lower income. Disinfection by-products (DBPs) have been associated with adverse reproductive effects and cancer. Exposure to DBPs may occur through ingestion of water, inhalation and dermal contact. This studied aimed to evaluate the relationship between DBP exposures and socioeconomic status (SES) with the hypothesis that higher social classes would be less exposed to DBPs through ingestion because to there greater ability to purchase bottled water. Also considered were other routes of exposure including dermal absorption and inhalation during showering, bathing and use of swimming pools.

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Data for this analysis were drawn from control subjects in the Spanish Bladder Cancer case-control study which involved 18 hospitals in five regions of Spain: Barcelona, Valles/Bages, Alicante, Tenerife and Asturias. A total of 1,219 bladder cancer cases and 1,271 hospital controls were recruited between 1998 and 2001for the case-control study. Controls were recruited from patients admitted to the selected hospitals for mainly minor surgery or trauma. There were 88% of controls that completed a face-to-face computer assisted personal interview (CAPI) that included sociodemographic information, smoking, occupation history, lifetime residential history, environmental exposures, medication and family history of cancer. The lifetime residential history information included the main type of water consumed at each residence (i.e. public water supply, private well or bottled water), although it did not request information about changes of type of drinking water in the same residence. Information was also included about: average daily water consumption (including water-based fluids such as coffee and tea); average frequency and duration of showers and/or baths; and ever lifetime swimming pool attendance. Data were collected from water utilities on current and historical levels of trihalomethanes (THMs).

Also THMs were measured in 113 tap water samples. Regions were stratified according to levels of THM measured with Barcelona, Valles/Bages and Alicante included in the high THM level areas (mean 64, SD 27 Âľg/l) and Asturias and Tenerife in the lower THM level areas (mean 17, SD 13 Âľg/l). Lifetime individual exposure indices were calculated by merging individual and municipal databases by year and municipality to obtain individual year-by-year average THM levels.

The educational level obtained by subjects was classified in 4 categories: illiterate, incomplete primary school, complete primary school (education through 13-14 years of age) and high school (through 17-18 years) or higher education. For some of the analyses there were two categories used: low education (subjects with primary school or lower) and high education (subjects with higher than primary education).

Income per person was calculated based on household income at the time of interview and number of family members living on that income. There were 3 categories of income per person: low (<300 Euros/month), medium (300-600 Euros/month) and high income (>600 Euros/month).

In the multivariate analyses where the use of public supply water among the illiterate was used as the referent, subjects who had attended primary school has a two-fold probability of consumption of bottled drinking water (OR = 2.1; 1.2-3.7) while the more

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highly educated subjects had over three times the probability of consuming bottled water (OR = 3.3; 1.8-6.0). The more highly educated subjects tended to take longer baths or showers and attended swimming pools more often than persons with a lower educational level. When income was used as a measure of socio-economic status, trends were similar to those found for educational level with 29% of subjects in the high-income category drinking botted water compared with 18% in the low-income category (p = 0.047). There were 8% of subjects in the low-income category that were swimming pool attendees, in contrast to 21% in the higher income category (p < 0.001). The time spent in the shower was not statistically significantly different by income.

There was an increase found in consumption of bottled water from 1980 to 2000 with 18% in 1980 to 20% in 1990 and 23% in 2000, with the greatest increase occurring where THM levels were the highest. Of those subjects with lower levels of education there were no changes over time in the use of water from public supplies (66% during 19801990 and 65% during 2000). Of those subjects with a higher education there was a decrease from 63% to 56% over the same time period in use of water from public supplies. In the same period there was an increase in bottled water use from 17% to 21% among subjects with a lower educational level and from 26% to 33% among the more highly educated subjects.

In this study, the use of bottled water, the use of swimming pools and the frequency and duration of showers and baths was higher among subjects with higher education and income compared to those with lower levels of either. This means that subjects of higher socioeconomic status would have lower exposure to chlorination by-products through ingestion but higher exposure through dermal contact and inhalation. Water consumption patterns may be affected by health risk perceptions and economic capacity that can in turn result in different exposures to water contaminants. The broader implications of this study are that socioeconomic status and exposure to DBP is complex and varies depending on the social and environmental context of exposed populations.

Fluoridation Drinking water fluoridation and osteosarcoma incidence on the island of Ireland.

Comber, H., Deady, S., Montgomery, E. and Gavin, A. (2011) Cancer Causes and Control, 1-6.

Osteosarcoma is a rare bone cancer with most cases occurring in young men under 25 years of age. There

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is also a smaller peak in incidence in those over 60 years. Understanding of the aetiology and pathogenesis of osteosarcoma is limited. The only risk factors defined for humans are radiation, some rare genetic disorders and possibly viral infections, however these factors are believed to account for only a small proportion of cases. A possible association between osteosarcoma and fluoride in water has been debated and the general scientific consensus is that there is no evidence of any link. In the UK, about 10% of the population receive fluoridated water, however fluoridation is not implemented in Northern Ireland (NI). In the Republic of Ireland (RoI), the population is served by a combination of public water supplies which are fluoridated and private individual or group schemes which are not fluoridated. This study compared the incidence of osteosarcoma in Northern Ireland with that in the Republic of Ireland to establish if differences in incidence between the two regions could be attributed to their different drinking water fluoridation polices.

Data was obtained from the Northern Ireland Cancer Registry (NICR) and the National Cancer Registry of Ireland (NCRI) for the 13-year period 1994-2006 inclusive. Cases of osteosarcoma were extracted from both registries. Cases were divided into ‘fluoridated’ and ‘non-fluoridated’ groups based on area of residence at the time of diagnosis. All cases in Northern Ireland were assigned to the ‘nonfluoridated’ group. For the Republic of Ireland, assigning cases was more complex due to the combination of water supply schemes in operation.

Each case was firstly assigned to an ‘electoral division’ (ED) of residence. Each ED was then assigned to an ‘urban’ or ‘rural’ category based on population density. Cases resident in rural EDs were considered ‘non-fluoridated’ and all other cases in RoI were considered ‘fluoridated’. The population data used included mid-year population estimates of NI and RoI census data for 1996, 2002 and 2006 interpolated for intervening years. The percentage of the RoI population assigned to the fluoridated group was approximately 67%.

Over the 13-year study period there were 183 incident cases registered (47 cases NI, 136 cases RoI). Most of the cases were diagnosed under the age of 25 and the highest incidence was in males aged 10-19 years.

There was no significance difference in any 5-year age-specific incidence rates between fluoridated and non-fluoridated areas for either males or females, with wide 95% confidence intervals (CI) reflecting the low numbers of cases in each 5-year band. For males in fluoridated area (RoIUrban), the overall age-standardised incidence rate

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was 0.32 cases per 100,000 per year (95% CI 0.230.41) and was not significantly different from that in non-fluoridated areas (NI and RoI-Rural combined), which was 0.29 (95% CI 0.22-0.37). For females the corresponding figures for all ages were 0.21 (95% CI 0.14-0.28) and 0.16 (95% CI 0.10-0.21), respectively and this was also not significant. There was little difference in age-standardised incidence rates for males under 25 years between fluoridated and nonfluoridated areas. Also standardised rate ratios (SRR) for males showed no evidence of any significant difference in osteosarcoma incidence in younger patients or overall. The incidence rate in RoI overall for females under 25 was 0.29 per 100,000 per year (95% CI 0.25-0.33) and was significantly higher than in NI [0.19 (95% CI 0.140.24)]. The rates however for females under 25 were highest in RoI-rural (non-fluoridated) areas and were 0.36 cases per person per year; 95% CI 0.28-0.43), higher than in either RoI fluoridated areas or NI. When incidence rates between fluoridated areas and non-fluoridated areas were compared, significantly higher rate ratios were found in relation to NI alone [SRR -1.43 (95% CI 1.07-1.90)]. Higher rate ratios were found when comparing non-fluoridated areas, RoI (Rural) and NI [SRR 1.86 (95% CI 1.33-2.62)], and they were statistically significant. The higher incidence rate was particularly seen in girls aged 1519 years.

This study showed little evidence of a significant effect of water fluoridation on osteosarcoma incidence at any age for either males or females. The higher incidence in young females in RoI in both fluoridated and non-fluoridated areas is clearly not related to fluoride in water. Bone cancer incidence rates in young females in both NI and RoI are lower than incidence rates in some registries in countries that have non-fluoridated water supplies such as Austria and the Netherlands. There are a number of limitations to this study including the relative rarity of the cancer and the corresponding wide confidence intervals of the relative risk estimates. If fluoride in drinking water does constitute an excess risk for osteosarcoma in Ireland, then the effect is too small for detection using current epidemiological methods.

Hepatitis E Novel risk factors associated with hepatitis E virus infection in a large outbreak in northern Uganda: results from a case-control study and environmental analysis Howard, C.M., Handzel, T., Hill, V.R., Grytdal, S.P., Blanton, C., Kamili, S., Drobeniuc, J., Hu, D. and

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Teshale, E. (2010) The American journal of tropical medicine and hygiene, 83(5); 1170-1173.

An outbreak of hepatitis E virus (HEV) began in October 2007 in the sub-county of Madi Opei in the northern Ugandan district of Kitgum. Several cases of unexplained jaundice (eventually confirmed as being caused by HEV) were reported by the health facility of a rural internally displaced persons (IDP) camp. By March 2008, new cases of hepatitis E began to be reported in four additional sub-counties in the district including Paloga, the focus of this investigation. By the end of 2008 more than 9,500 cases and 148 deaths had been reported. A casecontrol study and an environmental investigation was undertaken to identify risk factors and potential sources of infection in order to provide guidance to local health agencies for mitigation strategies.

The case-control study was undertaken from June 1724, 2008 in Paloga in the district of Kitgum because of its recent rapid increase in cases and its proximity to Madi Opei sub-county. Cases were defined as any individual with jaundice and at least one of the accompanying symptoms (fatigue, anorexia, abdominal pain, arthralgia, fever, or headache) and serological evidence of HEV infection. Cases were recruited by consecutive referral from the adjacent health centre. Controls were defined as those persons who had no symptoms, signs or serological evidence of HEV infection and were recruited from the community and were matched to cases on the basis of age group and location of primary residence in the previous 8 weeks.

Participants completed a structured questionnaire and were tested for HEV. The questionnaire collected demographic information and behavioural information. Also environmental information was collected including the main source, availability and treatment of drinking water, the type and number of drinking water storage vessels, handwashing practices, use and availability of soap and latrine availability and use.

Environmental samples were collected from Paloga and other nearby sub-counties that were affected by the outbreak. Water samples were collected from boreholes and hand pumps or from the tap stands of mechanised water distribution systems. A sample was taken from five households of their household water storage vessels. All samples were tested for residual chlorine before collection. Water was also collected from three streams that were used by local residents for bathing and washing and one pond.

Two pooled hand-rinse samples were also tested.

There were 112 cases patients and 145 controls enrolled in the study. In the adjusted univariate

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analysis, several variables were found to be associated at P < 0.20; bathing in the local river, storing drinking water in a large-mouthed container, preparation of rats for consumption, consumption of homemade alcoholic brew (often made from river water), washing hands in a common basin with others, eating from a common plate with others, promiscuous defecation and improper disposal of childrenâ&#x20AC;&#x2122;s faeces. A conditional logistic regression model was used to control for confounding and two variables were found to have remained significant: (P < 0.05): storage of drinking water in a large-mouthed container (Adjusted odds ratio (AOR) = 2.8; 95% CI = 1.16-6.94) and communal handwashing in a common basin with others (AOR = 1.9; 95% CI = 1.07-3.38). HEV RNA was detected from water filtered from two of the four surface-water sources, including the stream in Paloga. One of the two handrinse samples also tested positive. There was no HEV RNA detected in any of the 15 drinking water samples.

The results from this study highlight that poor hygiene and poor water storage practices played an important role in transmission of HEV during this outbreak. Communal handwashing is a relatively common practice in Paloga, especially during funeral services when a large number of relatives and friends congregate.

Post-collection contamination of drinking water, most likely at the household level must have occurred for the storage of drinking water in large-mouthed containers to be associated with acute hepatitis E. HEV transmission in crowded living conditions appears to have been multifactoral and may also have included person-to-person transmission. The factors that were responsible for the onset of the outbreak may not have been the same as those that allowed it to continue spreading over time. From the findings here it can be concluded that for future HEV epidemics, conventional control efforts at the community level such as water decontamination and provision of proper sanitation resources must also be supplemented by supplies, services and education related to personal and household hygiene measures.

Also in such situations, the availability of a safe and effective vaccine is very important and recent trials of an HEV vaccine are promising.

Mycobacterium Mycobacterium lentiflavum in drinking water supplies, Australia.

Marshall, H.M., Carter, R., Torbey, M.J., Minion, S., Tolson, C., Sidjabat, H.E., Huygens, F., Hargreaves, M. and Thomson, R.M. (2010) Emerging Infectious Diseases, 17(3); 395-402.

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Mycobacterium lentiflavum is a species of slowgrowing nontuberculous mycobacterium (NTM) which has been isolated from soil and water samples around the world.

However, links between environmental sources and human disease attributed to this organism have not been demonstrated. NTM disease (caused by a number of different mycobacterial species) is a notifiable disease in Queensland, Australia. In 2008, there were about 900 isolates of NTM reported. This study had two aims. Firstly to describe the clinical significance and outcomes of M. lentiflavum infection in Queensland and secondly, to explore the genotypic and geographic relationship between patient isolates and potable water isolates in the Brisbane area.

The records of all patients from whom M. lentiflavum had been isolated during July 2001 â&#x20AC;&#x201C; November 2008 were reviewed. During 2007-2008, potable water was collected from 206 sites in Brisbaneâ&#x20AC;&#x2122;s drinking water system and tested for the presence of Mycobacterium species. The similarity of 16 clinical and 7 water isolates was determined by using an automated repetitive sequence-based PCR (rep-PCR) method (DiversilLab).

From 36 patients, 47 isolates of M. lentiflavum were reported. Full clinical information was available for 32 patients. There were four patients (8 isolates) that had clinically significant diseases. There were seven patients that were taking treatment or were under surveillance for M. avium complex (MAC) (1 or 2 isolates each); as no treatment changed in response to the new isolate, these isolates were not considered clinically significant. There were 21 other patients (18 adults, 3 children) that had clinically nonsignificant isolates. Four patients had probable nonsignificant isolates but sufficient clinical information was lacking.

Mycobacteria were grown from 70% of the 206 water sites. The predominant isolates found were M. gordonae and M. Kansasii. M. lentiflavum was isolated from 13 sites of which 2 were reservoirs, 1 was a treatment plant and remainder were points in the distribution system. Eleven sites had the same groundwater source but were distributed among 10 different reservoir zones. Twelve patients who lived within 20 km of the Brisbane central business district had a mean distance between their residential addresses and nearest positive water site of 3.49 km (range 09-9.8 km). The 4 persons with clinically significant illness lived a mean of 2.7 km from a positive water site.

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DiversilLab patterns were grouped into 7 rep-PCR profiles, A-G. DiversilLab strain typing showed that profiles A and A3 were the most prevalent among clinical and water isolated and shared about 90% similarity. Four of the water samples constituting profile A3 and 1 unrelated strain (profile G) came from sites that had a shared groundwater source.

This suggests a dominant environmental strain closely related (90%), but not identical to strains found in humans and as a cause of human disease.

This theory of dominant local environmental strains is supported by the finding of a different strain type from 2 patients living near each other but 450 km from Brisbane (profile D).

M. lentiflavum is a rare isolate and an unusual cause of disease in humans. This study suggests potable water as a possible source of M. lentiflavum infection in humans. Clinical significance needs to be assessed before any treatment for M. lentiflavum infection is considered. In this study isolates for 4 (11%) of 36 patients were clinically significant which is similar to other published estimates of 10%-21%.

This however may be an underestimation given the clinical significance could not be determined in 4 patients.

Worldwide, M. lentiflavum may be underreported and incorrectly identified as other more familiar species, particularly if molecular identification is not performed.

Pathogenic E. coli Shiga toxin-producing Escherichia coli O100:H-: stx 2e in drinking water contaminated by waste water in Finland.

Lienemann, T., Pitkanen, T., Antikainen, J., Molsa, E., Miettinen, I., Haukka, K., Vaara, M. and Siitonen, A. (2011) Current Microbiology, 62(4); 1239-1244.

On 28-30 November 2007 in Nokia, Southern Finland, approximately 450 cubic metres of treated wastewater leaked into the drinking water distribution system due to a cross-connection, resulting in exposure of more than 10,000 inhabitants to contaminated drinking water. Over 1,000 people sought medical treatment for gastroenteritis over the following 5 weeks, but it was estimated that as many as 5,000 cases of illness may have occurred in the community. Five to ten stool specimens from patients with diarrhoea as well as drinking water samples, were collected for laboratory investigations soon after the outbreak was reported. A wide range of enteric pathogens were found in patients and have been described in other publications. This study describes diarrheagenic E. coli findings in a drinking water sample, as well as in stool samples collected from five patents just after the outbreak was reported.

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The water sample was taken on 1 December 2007 from the contaminated drinking water system from a tap situated near the sewage treatment plant which was the source of the contamination. A membrane filtration method was used for detection and enumeration of E. coli and coliform bacteria. On 2 December 2007, stool specimens were collected from ten patients with diarrhoea for culture of enteric pathogenic bacteria and norovirus.

Of these specimens, five primary cultures were further studied for diarrheagenic E. coli pathotypes. A 16-plex PCR was used to investigate whether the five major diarrheagenic E. coli pathogens [enteropathogenic (EPEC), enterotoxigenic (ETEC), Shiga toxigenic (STEC), enteroinvasive (EIEC) and enteroaggregative (EAEC)] were present in the contaminated drinking water and in the patients’ stool samples. The multiplex PCR targeted the following genes uidA, pic, bfp, invE, hlyA, elt, ent, escV, eaeA, ipaH, aggR, stx1, stx2, estIa, estIb and ast.

A STEC strain was isolated from the contaminated drinking water sample using an in situ hybridisation method and further characterised. A ready to use DIG labelled DNA probe (SSI) specific for the gene stx2, was used for the hybridisation.

Subtyping of the stx2, gene of the isolated STEC strain was performed by partial gene sequencing.

O:H serotyping and antimicrobial susceptibility testing for 12 antimicrobial agents was conducted.

Real-time PCR was applied for the detection of the following properties: the stx1, and stx2genes, the genes for the O26, O55, O91, O103, O111, O113, O145 and O157 O groups, the eae gene of E. coli O103 and the flagellar H7 antigen gene.

The results indicate that some patients might have had mixed infections involving two or three different E. coli pathotypes. Although human infections caused by the serotype O100:H- are rare and stx2e is the most frequent stx2 variant amongst STEC isolates from pigs, the possibility can not be excluded that a strain of this type could be pathogenic in the elderly or among children. There were several wellestablished enteric pathogens found to be associated with gastroenteritis in this large Nokia waterborne outbreak and only a few human stool samples were investigated for pathotypes of diarrheagenic E. coli.

Although the small number of stool samples tested here were negative for STEC, the involvement of STEC type O100: H: stx2e in this outbreak still needs to be clarified.

The concentrated water sample yielded very abundant growth of E. coli and coliform bacteria due to the massive faecal contamination of the drinking water. The water sample contained the genes uidA, pic, invE, hlyA, elt, escV, eae, aggR, stx2, estIa and astA. For four out of the five patients (D259, D260, D262 and D263), the gene escV was amplified from the primary stool cultures and three stool samples (D260, D262 and D263) were PCR–positive for the eae. Als,o the sample D260 was PCR-positive for estIa and elt, whereas D259 and D263 contained aggR and pic. The gene ipaH was only detected from stool sample D259. All of the stool samples apart from D262 exhibited the gene astA. A sorbitol positive, streptomycin resistant STEC strain was isolated from the drinking water and it was found to belong to the serotype 0100: H- and produced Stx2 toxin up to titre of 1:8. The strain also carried the uidA, estIa and irp2 genes. The partial stx2 sequence obtained was 100% similar to the sequence of the subtype stx2e in the sequence data bank.

Perchlorate is an inorganic compound that occurs naturally and from man made sources. Human exposure to perchlorate occurs through both food and water. In 2008, the US Environmental Protection Agency (EPA) estimated that as many as 16.6 million people in the United States may have been drinking water with perchlorate concentrations greater than 4 µg/L which is just below the California Public Health Goal (PHG) for perchlorate. Perchlorate is known to inhibit iodide uptake in the thyroid. Iodide is a precursor of thyroid hormone and therefore perchlorate at high doses may decrease the production of thyroxine (T4), the major form of thyroid hormone. The developing foetus and young children may be particularly susceptible to perchlorate as they are undergoing rapid neurological development which is highly dependent on thyroid hormone. These are also periods when thyroid hormone stores are low and a time when many infants may not be receiving adequate iodine intake.

Recent evidence has linked even mild decreases in thyroid hormone levels to adverse effects on foetal

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Comment This outbreak was reported in Health Stream Issues 48 and 49. According to media reports at the time, cases of Campylobacter and Salmonella infection were diagnosed among ill people, and norovirus was detected in the water distribution system. Subsequent journal publications documented infections by a wide range of additional bacterial and viral pathogens and Giardia among patients.

Perchlorate Perchlorate in drinking water during pregnancy and neonatal thyroid hormone levels in California.

Steinmaus, C., Miller, M.D. and Smith, A.H. (2010) Journal of Occupational and Environmental Medicine, 52(12); 1217-1224.

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brain development and childhood cognition. This study evaluated the associations between maternal drinking water perchlorate exposure during pregnancy and newborn thyroid hormone levels. In California, thyroid stimulating hormone (TSH) is measured in newborns just before the newborn leaves the hospital as part of a mandatory newborn screening (NBS) program. Elevated TSH is a marker for hypothyroidism as low levels of thyroxine hormone trigger the pituitary gland to produce more TSH in an attempt to stimulate thyroid activity.

Neonatal TSH levels were obtained from January to December 1998 as part of the California NBS Program.

This data also included: gender, race/ethnicity, the number of hours after birth when blood samples for TSH measurements were collected, birth weight, mother’s age, mother’s residence, multiple-birth status and feeding type (breast, formula, other). Information was obtained on perchlorate concentrations in the municipal water sources in California for the years 1997 and 1998 from the California Department of Public Health (CDPH) Drinking Water Program (DWP). This included more than 800 perchlorate measurements on more than 200 separate water sources and covered water sources supplying an estimated 66% of the state’s population. Californian communities were categorised into one of two groups of the basis of whether their estimated average perchlorate concentrations were more than (‘exposed’) or less than (‘unexposed’) 5 µg/L. Results were stratified by age at TSH collection, as there is a normal surge in TSH within the first few hours after birth.

After exclusions there were 497,458 subjects in the analysis. The median perchlorate concentration in active wells in the 1997-1998 data set with perchlorate concentrations more than the detection limit was 7.9 µg/L, with a high of 159 µg/L. The overall geometric mean TSH in all neonates combined was 4.06 µU/mL (SD = 5.75 µU/mL). The upper 95th percentile TSH values for collection ages before and after 24 hours were 15 µU/mL and 8 µU/mL, respectively. For neonates with collection ages less than 24 hours, the adjusted Odds Ratio (OR) for having a TSH of 25 µU/mL or greater was 1.53 (95% CI, 1.24 to 1.89; P < 0.0001) comparing perchlorate-exposed to unexposed communities. The corresponding OR for TSH levels at or above the 95th percentile for this collection age stratum (15 µU/mL) was 1.23 (95% CI, 1.16 to 1.31).

Statistical adjustments had very little impact on results. For neonates with collection ages of 24 hours or greater, the OR for having a TSH of 25 µU/mL or greater was 0.72 (95% CI, 0.41 to 1.27), although only 13 subjects from exposed communities had a TSH more

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than this level. The corresponding OR for TSH levels at or above the 95th percentile (8 µU/mL) was 1.27 (95% CI, 1.22 to 1.33; P < 0.0001; n = 2711 neonates from perchlorate-exposed communities with a TSH of 8 µU/mL or greater). This OR was still elevated in the analyses stratified by gender, race/ethnicity, and feeding type and after excluding high and low birth weights and extreme TSH values.

Also, adjustments only had small impacts on these results.

The results of this study suggest that perchlorate exposure is associated with increased neonatal TSH levels. Exposure to perchlorate could cause about a 23% to 57% increase in the number of neonates with a high TSH. This increase may be important given the widespread, ubiquitous nature of perchlorate exposure. This study highlights the importance of investigating effects in potentially susceptible groups such as young children. Several previous studies of perchlorate and thyroid hormone that found no associations were conducted in small numbers of healthy adult workers or volunteers and did not include susceptible groups. It is currently unknown whether the effects seen here can cause actual impacts on health and development, and further research is required. Also there is a need to evaluate the possible role that low iodine, thiocyanate (usually from smoking or certain foods), nitrate and other thyroid-active agents, that can also decrease T4 levels and increase TSH, may have contributed to these findings.

Comment The authors note that previous studies on the same dataset did not show an association between perchlorate exposure and congenital hypothyroidism, however this study looked at smaller changes in TSH levels than those used to define congenital hypothyroidism.

Pharmaceuticals Pharmaceuticals in drinking water: local analysis of the problem and finding a solution through awareness.

Leal, J.E., Thompson, A.N. and Brzezinski, W.A. (2010) Journal of the American Pharmacists Association : JAPhA, 50(5); 600-603.

There has been a great rise in pharmaceutical consumption evident by the increase in prescriptions sold in the United States (from 2.9 billion in 2000 to 3.4 billion in 2005) and the increase in pharmaceutical sales (from $79 billion in 2000 to $116 billion in 2005). There is accumulating evidence of the impact of pharmaceuticals in the water supplies and the magnitude of long-term

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effects is not known. Several studies have suggested that some of the drugs detected are already harming the ecological systems. New fish phenotypes have appeared near waste water effluent areas due to natural and synthetic oestrogens. Fish are showing gender blending with feminised male fish that lay eggs and/or have lost their reproductive abilities.

Also the widespread presence of antibiotics in the environment has been linked to the emerging antibiotic resistance and to interference with beneficial denitrifying bacteria in the environment.

There is currently no direct evidence linking pharmaceuticals in water to human health, especially as concentrations of medications detected in surface and drinking water are much lower than concentrations indicated to cause adverse effects upon acute exposure. Current human toxicological studies have relied on comparisons of a single drug and do not consider the risk of the synergistic effects of cumulative chronic exposure to a mixture of different drugs. This study aimed to evaluate the publicâ&#x20AC;&#x2122;s current knowledge of pharmaceuticals in drinking water and to discover ways to promote public awareness of the problem.

The Presidential Scholars Program at the Medical University of South Carolina is a multidisciplinary group of students and faculty from all six colleges at the university. One of the committees of this program conducted a one year project using several methods to increase public awareness of proper medication disposal. The first stage of the project involved literature reviews being conducted during a 6-month period to build a collection of background information. A publicly accessible website was created to organise and observe questions from the general public and environmental committee. A questionnaire was designed and distributed at various locations throughout Charleston including residential areas, churches, retail stores and on campus, to gain a better understanding of the publicâ&#x20AC;&#x2122;s knowledge and awareness about proper medication disposal.

Educational flyers were created and posted across the university campus to teach individuals about proper disposal of pharmaceutical agents.

There were 96 respondents who completed the questionnaire, with a mean age of 35 years (range 2080). There were 18% of respondents who were employed in health care. Of these, 13 (72%) had previous knowledge of pharmaceutical medications being found in local water supplies. Of those respondents not employed in health care, only 42 (54%) had previous knowledge. The source of all respondentsâ&#x20AC;&#x2122; knowledge about pharmaceuticals in water was mostly from the internet (46%) followed by television (17%) and newspaper (16%). There

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were 16 respondents who obtained information from multiple sources.

Of those respondents who indicated that they had previous knowledge of traces of medications in the local water supply, 7% disposed of medications in the toilet or sink, 38% used the trash, and only 36% reported using multiple methods, including one respondent who reported they took medications back to the pharmacy for recycling or disposal. Of those respondents who indicated they had no previous knowledge of medications in the local water supply, 3% disposed of medication in the toilet or sink, 35% used the trash and 42% used multiple methods.

None of these respondents reported taking their medications back to the pharmacy.

The results of this project suggest there is a need for more education about proper medication disposal.

As the majority of questionnaire respondents knowledge of pharmaceuticals came from the internet, future efforts at educating the public should include the use of online resources. Water treatment facilities are currently not able to screen for or extract pharmaceuticals from water supplies therefore other solutions need to be implemented to reduce pharmaceutical contamination of drinking water.

POU Treatment Bactericidal paper impregnated with silver nanoparticles for point-of-use water treatment Dankovich, T.A. and Gray, D.G. (2011) Environmental Science and Technology, 45(5); 19921998.

Cheap point-of-use methods are urgently needed to purify drinking water. There has been considerable interest recently in the use of nanotechnology for water purification. This paper describes an approach that used silver nanoparticles embedded in blotter papers to purify drinking water that is contaminated with pathogenic bacteria. The silver nanoparticles are produced by in situ reduction of silver nitrate solution on the cellulose fibres of an absorbent blotting paper sheet.

To test the bactericidal effectiveness of the AgNP papers, model bacterial suspensions were passed through an AgNP paper sheet and the effluent water was analysed for viable bacteria.

Relatively thick (0.5 mm) sheets of an absorbent porous blotter paper were used. Blotting paper sheets (6.5 cm by 6.5 cm) were immersed in 20 ML of silver nitrate solutions at concentrations from 0 to 100 mM for 30 min. To form AgNPs, the paper was placed in aqueous NaBH4 solutions for 15 min. The paper was then soaked in water for 60 min, the

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excess water was removed by drying the sheet in an oven at 60 °C for 2 to 3h. For some of the experiments, an untreated sheet of blotting paper was soaked overnight in about 20 mL of a concentrated AgNP suspension.

The sheets with adhering preformed AgNPs were dried and compared to the sheets with in situ-formed AgNPs. The amount of silver in the AgNP papers was quantified by performing acid digestion of the paper and analysing the amount of dissolved silver with inductively coupled plasma atomic emission spectrometer (ICPAES). The bactericidal activity of the AgNP paper was tested against a nonpathogenic strain of Escherichia coli, a Gram-negative bacteria and against Enterococci faecalis, a Gram-positive bacteria. These organisms are indicators for faecal contamination in drinking water. As controls, a untreated paper sheet and a paper sheet soaked with a 20 mL solution of 5 mM silver nitrate but left unreduced, to contain silver ions instead of silver nanoparticles was used. Graphite furnace atomic absorption spectrometry (GF-AA) was used to analyse the effluent passing through the AgNP paper for silver content. The silver loss from the AgNP papers in 100 ML of effluent was established from the GF-AA values for silver concentration in the effluent water. This value was expressed as a percentage of the total silver mass contained in the papers as determined by ICP-AES measurements.

The bacteria morphology was determined by transmission electron microscope (TEM) before and after percolation through the AgNP paper.

The silver nanoparticles were found to be readily formed by the in situ reduction of silver nitrate solution absorbed in the blotting paper. The sheets changed colour from white to yellow or brown with increasing precursor silver ion concentrations. Acid digestion of the AgNP papers showed silver content ranging from 0.2 to 20.4 mg of Ag per dry gram of paper. The lowest silver content was found in the papers that were soaked in the preformed nanosilver suspension. The AgNP paper provided rapid and effective bactericidal activity as model E. coli bacteria suspensions were poured through the paper.

The average percolation time for 100 mL of bacteria suspension was found to be 10 min. Some of the E. coli were retained in the filter, but most passed through. The bacteria growth after percolation through the AgNP papers was almost completely deactivated for the paper with the highest silver content (5.9 mg Ag/dry g paper). The papers containing lower silver amounts also showed a reduction in growth compared with the positive control. Plate count experiments showed log 7.6 (±1.3) and log 3.4 (±0.9) reduction of viable E. coli and E. faecalis bacteria, respectively in the effluent

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as compared to the initial concentration of bacteria (109 CFU/mL). The positive control also showed a reduction in bacteria by log 0.95 (±0.5), possibly due to some bacteria remaining on the fibre surface in the blotting paper. The paper prepared by soaking in preformed nonsilver suspension showed a modest reduction in bacteria count but was less effective than the AgNP papers prepared by the in situ reduction method.

The average silver content in the effluent water was 0.0475 (± 0.0177) ppm. Therefore the amount of silver leaching from the filter paper meets the USEPA guideline for drinking water of less than 0.1 ppm. The different samples leached between 0.04% and 2.4% of the initial silver content of the filter paper. Higher values for silver leaching were found with the AgNP soaked paper and the AGN03 papers, with 6.8% and 12.9% of total silver content lost, respectively, from the paper sheets. The in situ preparation of the silver nanoparticles in paper sheets was found to improve silver retention and the longevity of the water purifier This study shows that it is possible to demonstrate significant biocidal action as bacteria percolate thorough a paper sheet impregnated with silver nanoparticles. The bacterial action of the AgNP paper still needs to be tested in real-world situations, where disease-causing organisms exist in a medium containing a wide range of other organic, inorganic and colloidal contaminants. The results of this study will hopefully provide the basis for a water purification method that is light, cheap and effective as an emergency water treatment method.

Public Perception Public perception about drinking jar water and its bacteriological analysis Subedi, M. and Aryal, M. (2010) Nepal Medical College Journal : NMCJ, 12(2); 110-114.

Drinking water in Nepal has a high rate of contamination, waterborne diseases are endemic and there are frequent outbreaks. During 1995/96, the incidence of diarrhoea among children under five years was 131 episodes per 1,000 children. The mortality rate due to diarrhoea was 0.34 per 1000 children under five years and the case fatality rate was 2.56 per 1,000. The Kathmandu Valley suffers from a severe drinking water supply crisis, particularly in the dry season each year. The piped drinking water supply in the cities of the Valley is intermittent. The consumption of jar bottled water has been consistently increasing.

This study examined the public perception of jar water supplied

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in the Kathmandu Valley and its bacteriological quality.

The study was conducted between August and December 2009 in thirty five wards in the Kathmandu Valley. There were 57 different jar bottles found in the wards. The selection of each jar was random from each new jar company. Two samples were collected from the same company to minimise result errors. Therefore there were 114 samples collected. Water samples were examined for different species of bacteria as well as faecal coliform bacteria. The antibiotic sensitivity patterns of faecal coliforms were also examined. A semi structured questionnaire was used to interview 525 persons who were using jar water for drinking purposes.

Of the525 respondents using jar water as a source of drinking water, 18.4% rated the quality of jar water as very good, 61.7% as good, 13.1% as satisfactory, 5.7% as poor and 0.9% as very poor. Most people were keen to check the quality of their jar water, despite assurance of quality by water companies, with 78.4% of people very concerned (very important to check) and 15.2% concerned (important to check).

There were only 2.0% of respondents that suspected that they or a family member had become ill as a result of a private jar water supply. Convenience was a major motivating factor for buying jar water, people who would normally drink tap water would be motivated to buy jar water on occasions when tap water was unavailable. Convenience, cost and taste were all influential factors when making decisions whether to buy bottled water; health beliefs however were not important motivating factors.

Of the 57 different jar bottles tested, 91.2% (52/57) were found to be contaminated with total coliforms and 59.6% (34/57) were found to have faecal coliform contamination. There were no significant differences in the results for positive coliforms in the two consecutive samplesfrom each company. Of the 117 isolates found, the majority were E. coli (33.3%) followed by Klebsiella spp (23.9%) and Enterobacter spp (17.0%). E. coli the most common faecal coliform bacteria (43.1%) followed by Klebsiella spp (39.6%) and Enterobacter spp (17.2%).

It was found that most of the jar companies get their source water from either a peripheral area of the valley or near the mountains. Several studies have shown that there is a high rate of drinking water contamination in the Kathmandu Valley and other mountain regions. This study presents an alarming situation where the quality of jar water is poor. The distribution of such contaminated water without proper treatment poses a threat to public health. The

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reason for this poor quality was may be because of inadequate treatment by private water companies or that the jar bottles that are used for filling water are not properly cleaned.

Rotavirus A waterborne outbreak of epidemic diarrhea due to group a rotavirus in Malatya, Turkey.

Koroglu, M., Yakupogullari, Y., Otlu, B., Ozturk, S., Ozden, M., Ozer, A., Sener, K. and Durmaz, R. (2011) New Microbiologica, 34(1); 17-24.

This paper characterises a large outbreak of waterborne acute diarrhoeal disease caused by group A rotavirus in Malatya City, Turkey during the Autumn of 2005. The outbreak was recognised on 21 November 2005, when there was an unusual increase in acute diarrhoea disease among patients admitted to two state hospitals from two large districts of Malatya. The number of patients with abdominal pain, fever and vomiting progressively increased with approximately 10,000 patients with similar clinical symptoms attending health care centres over the following 14-day period.

A multidisciplinary investigation team was established to investigate the outbreak.

Almost all of the Malatya City inhabitants use piped fresh municipal water, which is supplied from a large spring water source about 15 km away. The water is treated at the source before distribution to six major water depositories in different parts of the city. The water is then distributed from these depositories to districts and to the homes via the pipeline system.

There is also one water well which provides water to a major water depository (Inderesi Water Depository) that supplies fresh water to two main districts in the city centre and to three student hotels in the Inonu University Campus settlement. Data was collected by the Health Department from diarrheic patients who attended any health institute between 21 November and 4 December 2005 and included age, sex, localisation, major symptoms, duration of illness and travel history. Those patients whose diarrheic symptoms were explained by infection with a usual pathogen were excluded from the outbreak investigation.

During the outbreak, an average of 100 pipeline water samples were collected each day from different districts of the city and analysed. Water samples were analysed by the Public Health Laboratory for the presence of coliform bacillus as well as chemical parameters including Free Chlorine Concentration (FCC).

During the outbreak further chemical analyses and confirmatory bacteriological tests were

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conducted by another laboratory, however techniques to test for rotavirus in water were not available. There were approximately 3250 stool samples examined for the presence of diarrhoea-causing parasites. Faecal samples were examined using chromatographic immunoassay rotavirus antigen detection kits. The faecal samples with detectable rotavirus antigen were then submitted to molecular analysis. Samples were subjected to reverse transcription-polymerase chain reaction assay (RT-PCR assay) for amplification of the VP9 gene group A rotavirus.

The highest attack rates were recorded from the supply area of the Inderesi Water Depository. A relatively low attack rate was obtained from the Inonu University Campus. Very low FCC levels may have facilitated the epidemic spread of the pathogen until 26 November 2005. After this date the FCC levels increased considerably in the pipeline water and the outbreak progressively decreased to the expected normal level by 4 December 2005. The mean age of the outbreak patients was 25 years. The disease was significantly more symptomatic in young children under 5 years of age. There were 2931 water samples received and analysed during the outbreak. Coliform bacilli growth were detected in only 26 water samples collected from different locations that did not included the two affected districts. None of the samples grew Salmonella, Shigella, Vibrio cholorae, Campylobacter and toxigenic E. coli. Chemical measures of the water samples were all in normal ranges apart from FCC, which was as low a 0 to 0.05 mg/L in most districts.

There were 1714 (52.7%) of the 3250 stool samples found to be positive for rotavirus antigen. In 33 of the 38 tested faecal samples RT-PCR resulted in amplification of a 1062-bp DNA band that is indicative of Group A rotavirus.

Data obtained retrospectively on the water distribution program of the water department showed that water interruption was frequent at the main water source because of intense substructure work in the west side of the city. To supply the required water to the east side settlements, the municipality’s water department authorised the use of a water pump at the well of the water depository. Approximately 60 L/s of untreated water was offered for use from 18 November 2005. The epidemic pathogen was easily spread in the piped municipality water systems as the levels of FCC measured in the drinking water were low.

The outbreak was stopped by effective chlorination and blockage of the passage between the well and the water depository. This is probably the largest rotavirus outbreak in Turkey as well as in Europe. This study shows the ability of rotavirus to cause acute water diarrhoea epidemics which affect

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large human populations and underlines the importance of water hygiene in the pipeline system.

Water Quality An assessment of microbiological water quality of six water source categories in north-east Uganda.

Parker, A.H., Youlten, R., Dillon, M., Nussbaumer, T., Carter, R.C., Tyrrel, S.F. and Webster, J. (2010) Journal of Water and Health, 8(3); 550-560.

One of the Millennium Development Goals, 7C is to “halve by 2015, the proportion of people without sustainable access to safe drinking water and basic sanitation”. However, the indicator for monitoring the proportion of people with sustainable access to safe water is an indicator which measures the “proportion of population using an improved water source”. This raises the question as to whether “safe” and “improved” can be interchanged for each other.

This paper aims to assess the safety of improved water sources in terms of microbiological water quality by comparing the water quality of six different source types, four of which are improved according to the WHO and UNICEF Joint Monitoring Programme (2008) definition (boreholes, protected springs, roof water harvesting and covered hand dug wells) and two unimproved sources (open hand dug wells and open water). This paper also investigates whether sanitary surveys are a useful measure of improvement as poor construction or maintenance of the source improvements can lead to unsafe water.

The study was undertaken primarily in Amuria District in NE Uganda, although some sites were visited in the neighbouring districts of Katakwi and Soroti. To assess water quality, thermotolerant coliforms (TTC) were used in this study as faecal indicator organisms. WHO (2006) guidelines for safe water state the TTC should not be present in 100 ml sample, however it is acknowledged that this target may not be realistic in low income countries.

In Uganda , the Ministry of Water and Environment (2006) has adopted a maximum level of 50 TTC/100 ml for untreated water. Turbidity measured in-situ was also used as an indicator of water quality. A sanitary survey was also performed which included a series of questions that were used to assess the quality of construction and maintenance of a water supply. Each “yes” answer corresponds to an aspect of poor construction or maintenance. Data collection was conducted between May and July 2008 and 346 sources were visited. Most water sources were sampled in each village.

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Of the four water sources being defined as safe according the WHO and UNICEF Joint Monitoring Programme (2008), there were 89% of boreholes that met the Ugandan national standards, only about 60% of protected springs and roof water harvesting sources met the standards and only 26% of covered hand dug wells met the standards. A similar trend was also found in sources meeting WHO standards.

The source types were compared according to the two indicators of water quality, TCC and turbidity. It was found that the source types ranked in descending order of water quality from the highest to the lowest were as follows: boreholes, protected springs and roof water harvesting, open and covered hand dug wells and open water.

Total sanitary survey scores were not found to correlate well with water quality, which means that poor sanitary scores do not necessarily indicate sources need improvement. This is contrary to previous findings and the reason for this could be that this study was conducted during the dry season, and measurements were only made at one point in time.

Water quality is typically compromised following rainfall events and it is often rainwater than transports coliforms into the water source, so lower levels of microbiological contamination would be expected during the dry season.

and therefore turbidity is not an acceptable indicator of water quality.

This study does suggest that “improved” water sources are “safer” than unimproved sources, however the study shows that not all “improved” sources are “safe”. The Millennium Development Goal target 7C indicator measures the proportion of the population using an “improved” source, however there may be significantly less people using a “safe” source. Improved sources need to be well maintained if they are to give protection to a water supply in the long term. Sanitary surveys may be useful to highlight the main aspects of possible improvement, however these may not always be relevant. Sanitary surveys cannot be used to precisely predict water quality, never-the-less they are widely considered to be an essential part of the monitoring of safe water supplies.

The study also examined the question “If this sanitary survey question is answered positively, is the water likely to be of poor quality?” For TTC, the only two questions to which a “yes” answer gave significantly poorer water quality were: in open hand dug wells, “Are there cracks in the concrete apron, or is the apron absent?”; in protected springs, “Is the outlet dirty?”. Using turbidity there were no significant questions to which a ‘yes’ answer gave significantly poorer water quality. For many questions there were very few ‘yes’ answers, meaning the sample sizes were small. As some of the questions were similar, it was possible to group data and reanalysed for all the groundwater sources together (boreholes, open hand dug wells, protected springs and covered hand dug wells). Both high TTC and high turbidity correlated with failures in the apron. High turbidity values also correlated with failure in the drainage channel. High TTC correlated with the absence of a fence (which allows animals near the well, whose excreta could be a source of contamination).

The two indicators were compared and it was found that when turbidity is high, TTC is also high, but when TTC is high there is a wide range of turbidity.

This suggests that if turbidity is used alone as an indicator of water quality then sources may appear to be safe when in reality they have a high TTC count

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