Universität Stuttgart Msc. Study Program WASTE
Pesticide Air Monitoring in the Atlantic Zone of Costa Rica
Report on Planning, Quality Control and Quality Assurance of Measurements Summer Semester 2012
Group No.: 1 Student Family Name
First Name
Matr.-No.
E-Mail/ phone no.
Perez Sierra
Johanny A.
2730310
j.arilexis@gmail.com
Supervisor’s name:
apl. Prof. Dr.-Ing. G. Baumbach / Dr.-Ing. Vogt
Institute of supervisor:
Institute of Combustion and Power Plant Technology
Date of delivery:
31.07.2012
Table of Contents LIST OF FIGURES ....................................................................................................................III LIST OF TABLES.......................................................................................................................III INTRODUCTION ...................................................................................................................... IV 1
PROBLEM ANALYSIS ........................................................................................................1
1.1
Background information ...................................................................................................1
1.2
Site description and Climate conditions ...........................................................................5
2
MEASUREMENT STRATEGY ............................................................................................7
3
MEASUREMENT TECHNIQUE...........................................................................................8
3.1
Time resolution ................................................................................................................8
3.2
Performance characteristics ............................................................................................8
3.2.1
Description of method......................................................................................................8
3.2.2
Extract from the EPA Method TO-4A ...............................................................................9
3.2.2.1 Sampling .........................................................................................................................9 3.2.2.2 Sample clean-up and extraction ....................................................................................14 3.2.2.3 Sample analysis ............................................................................................................15 3.2.2.4 Method TO 4A Parameters ............................................................................................17 3.3
Standardization of the measurement procedure ............................................................17
3.4
Infrastructure for using measurement techniques ..........................................................17
3.5
Data recording and documentation of the measured values ..........................................17
4
QUALITY ASSURANCE ....................................................................................................20
5
EVALUATION ...................................................................................................................21
5.1
Detection limits ..............................................................................................................21
5.2
Calculation of pesticides in the air .................................................................................21
5.3
Method precision and bias .............................................................................................22
5.4
Overall measurement uncertainty ..................................................................................23
5.5
Uncertainty of the results ...............................................................................................23
6
ORGANIZATION ...............................................................................................................24
7
CONCLUSION ..................................................................................................................26
8
REFERENCES..................................................................................................................27
9
APPENDIX ........................................................................................................................28
ii
List of Figures Figure 1. Main processes related with the environmental fate of pesticides in the environment. Cg, Cs and Cw represent the concentration in gaseous, aqueous and solid phases. Source: Walters, 2003......................................................................... 2 Figure2. Process scheme of the diffusion of pesticides from soil to the atmosphere. Source: Walters, 2003. ............................................................................................. 3 Figure 3. Average rainfall and temperature in Puerto Limon, Costa Rica []..................... 6 Figure 4. Annual statistic of wind direction distribution in Puerto Limon, Costa Rica [].... 6 Figure 5. Identification of the sites of measurement in Limon, Costa Rica. ..................... 7 Figure 6. Typical high volume air sampler for monitoring pesticides and Polychlorinated Biphenyls in ambient air. ........................................................................................ 10 Figure 7. Adsorbent cartridge assembly for sampling common pesticides and Polychlorinated Biphenyls. ..................................................................................... 11 Figure 8. Portable high volume air sampler developed by EPA. ................................... 11 Figure 9. Exemplary of materials employed in sample collection. ................................. 12 Figure 10. Set up of field calibration system of HVSs of pesticides and PCBs. ............. 13 Figure 11. Apparatus used for sample clean-up and extraction. ................................... 15 Figure 12. Chromatograph showing a mixture of single component pesticides, employing GC/ ECD with a capillary column. ......................................................... 16 Figure 13. Field test data sheet. .................................................................................... 18 Figure 14. Orifice transfer standard field calibration data sheet. ................................... 19 Figure 15. Personnel planning for the pesticide air monitoring in Limon, Costa Rica.... 24 Figure 16. Scheduling for the measuring of pesticides in Limon, Costa Rica. ............... 25
List of Tables Table 1. Technical package for field management in banana cultivation. ..................... 28
iii
Introduction
Costa Rica is a Central American country which among the main “cash crops� it is included the banana production. This sector generates most of employments in the Atlantic zone of the country, where bananas are produced intensively and in large extension of lands.
Despite its significant economical relevance, banana production threatens rural communities surrounding the plantations, and also it affects the ecosystems in this region due to the large use of chemicals to control the growth of the plantation and to avoid the infestation of pests.
Pesticides are applied in large quantities and very frequently. Depending on the climatic conditions, the method of application and the structure of the soil, pesticides can be driven away from the site of application and be deposited up to mountainous zones in the country, while also, may increase its residence time in the atmosphere, undergoing chemical transformations and/ or being deposited back to the ground by wet or dry deposition.
It is important to keep track of the concentration of pesticides in the atmosphere because of its potential impact on human health (esp. cancer and fertility reduction), impacts on nature (quality of water, biodiversity limitation, etc.) and its dangerous residence time in the atmosphere may affect present and future generations.
In this project, high volume active samplers are used according to the method TO 4A of the EPA in order to determine the most frequently used pesticides in the banana production of the Atlantic zone of Costa Rica and its seasonal variations during a period of a year.
iv
1 Problem Analysis 1.1
Background information
Costa Rica is a Latin American country, located in Central America. Agriculture is 6.9% of the national GDP, and the main cash crops are banana, pineapple, rice and coffee[1]. Banana production is the main agricultural activity generator of incomes in Costa Rica, and the third main product of exportation which principal markets are the USA, Sweden, Germany and Belgium. In 2004, exportations from this sector generated 533 Millions US$, making available 28,311 employments[2]. Banana plantations are mainly established in the Atlantic zone, surrounded by rural communities and the humid tropical rain forest. In order to reduce pest infestation in the fruits, growers employ agrochemicals, commonly known as “pesticides”. Large plantations apply the pesticides in its liquid form using “aerial application” or “crop dusting” mainly done by agricultural aircrafts. In 1996, banana production represented 57% of total used imported pesticides in Costa Rica, which was 1.175.703, 50 kg active ingredient (a. i.). The banana industry applies pesticides intensively to make production profitable, but this means large uses of active ingredient per hectare. In the table 1, appendix A, there is a list of commonly used pesticides for the banana production in a.i. / ha in 1996, and type of control in the crop[3]. Despite most of the pesticides in the list are already banned, there may still reside in the environment. Pesticides are classified according to its origin: natural or synthetic, according to toxicity: extremely hazardous, highly hazardous, moderately hazardous and lightly hazardous; according to their half life, they can be grouped as: permanent, persistence, moderately persistent, and according to its chemical structure, main families are: organochlorates, organophosphorates, carbamates and piretroids[4]. Once pesticides are applied, they may be either degraded or transported involving many different processes. Wolters, 2003[5] indicates that the movement of pesticides is influenced by the inner chemical and physical characteristics of the pesticide, conditions in the place of applications, such as: soil, geology, vegetation, climate and local weather status, and also, by the method of application. In figure 1 is presented the main events related with the movement of pesticides in the environment. According to the same author, the atmosphere is the principal vector for distribution of pesticides. In agriculture the emissions of pesticides may occur during and post application. During the application, the main phenomenon is off-target drift, which can be even 75% of the total dose. [1]
Central Intelligence Agency (CIA). [2012]. The World Fact book: Costa Rica. Steiner, R. 2006. Utilización Energética de Residuos Orgánicos de la Industria Bananera. [3] De los Santos, Pratt and Pérez. Uso de plaguicidas en la Agroindustria de Costa Rica. [4] Ramírez, J. and Lacasaña, M. 2001. Plaguicidas: clasificación, uso, toxicología y medición de la exposición. [5] Wolters, A. 2003. Pesticide Volatilization from Soil and Plant Surfaces. [2]
1
Drift is influenced by the application method, formulation and formation of spray clouds. The volatilization occurs after the application is completed and the pesticide can travel long distances appended in dust particles.
Figure 1. Main processes related with the environmental fate of pesticides in the environment. Cg, Cs and Cw represent the concentration in gaseous, aqueous and solid phases. Source: Walters, 2003. Volatilization can occur from bare soil and from plant surfaces. As shown in figure 2, in the process of volatilization from bare soil, the pesticide first desorbs from the soil solids into the soil interstitial solution, partitioning later into the soil air; from there, it can be transported into the boundary layer and the lower atmosphere via diffusion. The flux is influenced by concentration gradient, temperature, surface roughness, and soil profile. The main factors that influence the volatilization from soil are: characteristic of the pesticide, method of application and soil’s physical properties. However, volatilization from plants is the main route of emissions. In the leaves, the process is influenced by the physicochemical properties, residence on the leaves, environmental parameters and vapor pressure of pesticides; this latter increases with high temperatures. Once volatilized, the pesticide enters into the boundary layer, which is unstably stratified and well mixed by mechanical and thermal turbulence during the day and extended along several kilometers.
2
During the night, the layer’s depth is reduced due to surface cooling, and is quiescent. Under these conditions, pesticides are well mixed during the day, traveling throughout the boundary layer, and during the night can travel horizontally long distances with low dilution. When pesticides reach mid- and upper troposphere (5-16 Km), their residence time increase constantly. In the upper atmosphere, their transportation is governed by global wind circulation patterns.
Figure2. Process scheme of the diffusion of pesticides from soil to the atmosphere. Source: Walters, 2003. Removal and thus, residence time of pesticides in the atmosphere, is controlled by chemical reactions and deposition, this latter can be dry or wet, when involves precipitation. The removal processes are influenced by the physical and chemical composition of the pesticides, meteorological conditions and the depositional surface status. Dry deposition of pesticides is affected by gravitational settling and turbulent movement to a surface with interception or diffusion onto surfaces, such as vegetation, soil and water; while, wet deposition includes: rainout when cloud droplets host pesticides’ particles, and washout which occurs when pollutants are removed by rain, by scavenging of particles or portioning of organic vapors into the rain. These types of deposition have a higher influence at distances far from site of application and depend of the solubility of the pesticide. Photochemical reactions are the most important in pesticide removal. Photodegradation occurs by direct adsorption of sunlight or by indirect reaction with photochemical generated oxidants, i.e. ozone and hydroxyl radicals. 3
It is relevant to determine concentration of pesticides in ambient air because of their impact on ecosystems, health and infrastructures. Santamaria-Ulloa, 2009[6] found direct correlations between high pesticide environmental exposure and breast cancer among women aged -under 30 in Costa Rica. This scenario was intensified in the regions of banana and rice production. Banana is mainly produced in the Atlantic eastern zone of the country where fertility rates in women are medium compared with national values and social lag ranges from medium to high. According to the Pan-American Health Organization[7] (OPS, acronyms in Spanish), in Central America, paraquat, metomil, terbufos, metamidofos and etoprophos were the main responsible for intoxications and dead, most of them are currently banned. In the period 1967-1979, 1500 workers from the banana industry were sterilized with dibromocloropropano (DBCP), a nematicide, which was later banned. It was demonstrated that there was a direct relationship between amount of hours worked and sterilization of workers. In 1986 it was published a study on the residues of pesticides in adipose issues from 16 hospitals from throughout the country, from women and men and from urban and rural areas. Results showed that DDT was the most predominant pesticide. This pesticide was used during 3 decades for controlling malaria and pests, but in 1998 it was prohibited, however, studies showed it still remained in the organism of exposed people. For the period 1995-1997 a study showed that women working in the packing stage of banana industries presented higher damages in chromosomes and existence of abnormal cells, precursors of cancer. In the environment, the use of pesticides reduces biodiversity, pollutes ground and surface water and atmosphere, provokes loses of permeability in the soil, and increases vulnerability to pests and diseases, while leads to disequilibrium of agroecosystems and surroundings. In Costa Rica, the amount of pests for banana increased from two to eleven, between 1950-1960 due to a raised resistance of pests to dieldrin7. Some studies developed in Costa Rica, have showed transport and deposition of pesticides to high altitude forest in the humid tropic. Shunthirasingham et al.[8] found in a study employing passive air samplers (PASs) that annually averaged air concentrations of chlorothalonil, endosulfan, and pendimethalin are higher in areas with influence of large agricultural activities. Pesticides levels from high elevations were generally below 10 ng L-1. Daly et al[9], employing PASs found high concentrations of chlorothalonil, dacthal and endosulfan sulfate on volcanoes Barba and Poas which are downwind of the banana plantations in the Caribbean lowland, showing atmospheric transport and wet deposition of pesticides at elevated zones of Costa Rica.
[6]
Santamaria-Ulloa.2009. The Impact of Pesticide Exposure on Breast Cancer Incidence. Evidence from Costa Rica. Organización Panamericana de la Salud. 2003. Efectos de los plaguicidas en la salud y el ambiente en Costa Rica. [8] Shunthirasingham, C. et al. 2011. Current use pesticide transport to Costa Rica’s high altitude tropical cloud forest. [9] Daly et al. 2007. Accumulation of Current Use Pesticides in Neotropical Montane Forests. [7]
4
In order to determine the presence of pesticides in the Atlantic Zone of Costa Rica, this study aims to identify the existence and type of pesticides in ambient air in selected agricultural emission sources (banana plantations) and surrounding communities, to determine its seasonal concentrations during a sampling period of a year. These results will be then analyzed to determine the correlation between seasonal pesticides air concentration, spatial distribution and weather conditions. Measurands will consist on the concentrations in pg m-3 of the following contaminants: persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and furans (PCDFs), polynuclear aromatic hydrocarbons (PAHs), organophosphorus and organochlorine pesticides (diazinon, chlorpyrifos, malathion, toxaphene, DDT). In terms of standards, there is little information regarding the regulation of presence of pesticides in ambient air. In Costa Rica, there are regulations in terms of concentration of pesticides in food and registration of pesticides; however, it was not found information regarding legal frame of limit values. For PCDDs and PCDFs, the Ontario Ministry of the Environment and Energy in 1994 established a value of 5 pg I-TEQ m-3 in a 24 h average and for PCBs a limit of 0.035 µg m-3. In the state of Connecticut, in the USA, PCDDs and PCDFs are set for a concentration of 1 pg I-TEQ m-3 in ambient air[10].
1.2
Site description and Climate conditions
The site of measurement is Limon. This is a province of Costa Rica, located in the eastern part of the country in contact with the Atlantic ocean. The coordinates of Puerto Limon are 9° 56′ 0″ N, 84° 5′ 0″ W. This region is characterized as a tropical forest with, humid and rainy weather. As it is showed in the figure 3, the average temperature is 25.3°C and the annual mean precipitation of 3518 mm. As it is showed in the figure 4, the average wind speed in Limon province is 4,3 m/s with a direction going from north-east to the south-western zone of the country.
[10]
Buckland, Ellis and Salter. 1999. Organochlorines in New Zealand: Ambient Concentrations of Selected Organochlorines in air.
5
Figure 3. Average rainfall and temperature in Puerto Limon, Costa Rica [11].
Figure 4. Annual statistic of wind direction distribution in Puerto Limon, Costa Rica [12].
[11 ] [12 ]
http://de.wikipedia.org/wiki/Costa_Rica http://www.windfinder.com/windstats/windstatistic_puerto_limon.htm
6
2 Measurement strategy The duration of the measurement program is one year and the sampling frequency is set to be once every 1 week, during a sampling time of 24 hours. This strategy was chosen due to the high costs involved in the analysis of the samples and the characteristics of the equipment to be used, described in the next chapter. Under this strategy, it will be collected 24 samples/ site and it will be achieved 46% of the total sampling period, getting a representation of the fate of pesticides from the site of emission to the immision locations. Sites of measurements are three: A. Siquirres, main zone of banana production (pesticides emission source), B. Guapiles, which is a rural community in the surroundings of the plantations thus to determine potential exposure to the pesticides and C. National Park Braulio Carrillo, a mountainous region, 117 km away from the plantations, to determine the influence of the pesticide in other regions up to higher altitudes. In the figure 5, it is a map with the indication of the site of measurement. Supplementary measurements carried out in conjunction with the main measurements, include the determination of: precipitation (mm/min) and humidity (%), wind speed (m/s) and direction, temperature (째C), and solar radiation (kWh/m2).
Figure 5. Identification of the sites of measurement in Limon, Costa Rica.
7
3 Measurement Technique 3.1
Time resolution
The sampling period will be deployed during a year, employing high volume active air methods. Samples will be collected once every two weeks with durations of 24 h to fulfill the performance characteristic of active measurement of pesticides[13]. This time resolution allows to obtain annual mean values and to cover different crop seasons’ applications and to determine the influence of pesticides in situ and off target areas.
3.2
Performance characteristics
3.2.1 Description of method Pesticides can be sampled using either active or passive (diffusive) samplers. Concentration of pesticides in the atmosphere vary from 0.1 pg m-3 to 10 pg m-3, for this reason, most of the samplings in ambient air employ high volume samplers (HVSs) with a pumping flow rate up to 13-30 m3 h-1[14]. Active air samplings (AASs) are executed in short periods but with high frequency. This method provides accurate quantitative concentration data, information regarding gas/ particle phase and high temporal resolution. It is advisable to be used when the objective is to determine factors influencing short term concentration variability, like: temperature, wind speed and direction. However, its disadvantages include high maintenance and cost operation, and also, constant supply of electricity. In contrast, operation costs for passive air samplings (PASs) are lower and the method does not require electricity to operate. PASs are recommended to be used for spatial resolution information and in remote areas. PASs are recommended when long sampling periods are desired [10]. For this study, AASs with HVSs are considered in order to cope with the temporal resolution of the stated objectives. Active sampling involves pumping of air through a filter and a solid adsorbent, allowing the measurement of pesticides in gaseous and particulate phases. Commonly, high volume samplers are used with a flow rate of 30 m3 h-1 for 24 h, which is sufficient to detect concentration of pesticides and to avoid clogging of filters. The materials for sample collection include: a filter and an adsorbent. Pesticides in particulate matter can be filtered employing: glass fiber filters (GFFs) or quartz fiber filters (QFFs). Among the adsorbents, it can be listed: XAD-2, XAD-4, PUF, Tenax-TA. PUF has been used for 57 common pesticides as is the recommended by the EPA Method TO-4A.
[13] [14]
Hayward, J. 2010. Fate of Current used pesticides in the Canadian Atmosphere. Yusa et al. 2009. Sampling and analysis of pesticides in ambient air.
8
The analytical procedure involves extraction, clean up during extraction and before sampling, and detection or determination. In the extraction, it is intended to obtain as much pesticide as possible from the sampling devices. Current methods employ liquidsolid extraction (LSE) with a specific organic solvent. The technique most employed is Soxhlet, because it is low cost and has a proven applicability in different standardized analytical procedures. This extraction can be performed with different solvents, with unique substances like acetone DCM or as a mixture, like hexane-DCM, DCM-light petroleum (PE), cyclohexane-acetone or hexane-acetone. During sampling and extraction, many organic substances can be collected and coextracted, latter these interfere with the main analytes which difficult its identification and quantization; for this reason a clean-up step is required. The Silica Pesticide Extraction (SPE) is the type of column mostly used. The sorbents that are mainly used include: Florisil (synthetic magnesium silicate), alumina, silica gel, or a mix among them, like alumina-silica or alumina-Florisil. This technique is a polar based sorbent. Before sampling, traps are also cleaned-up; the most common method is Soxhlet, the same used for extraction. For detecting the analyzed substances, detectors are changing from the classical Gas chromatography (GC) to more sensitive and selective ones. Currently, the types of detectors are GC and High performance liquid chromatography (HPLC). The detection methods employed with GC include: electro capture detection (ECD), nitrogenphosphorus detection (NPD) and mass spectrometry (MS) which is the most widely used, and for multiresidue analysis, electron ionization (EI) in positive mode is commonly employed. The HPLC is mainly chosen when polar, thermal-labile substances are measured, the detection methods include: HPLC-UV and LC-MS/MS [10].
3.2.2 Extract from the EPA Method TO-4A Description of Apparatus[15] 3.2.2.1
Sampling
High volume sampler: with capacity of pulling air through the filter/ adsorbent cartridge at a flow rate of 0.225 m3 /min along a 24-hour period, showed in figure 6. Main suppliers in the US are:
Tisch Environmental Andersen Instruments Inc. Thermo Environmental Instruments Inc.
[15]
Winberry, W., Riggin, R., Lewis, R. 1999. Compendium of methods for the determination of toxic organic compounds in ambient air: Compendium Method TO- 4A. 2nd ed.
9
Figure 6. Typical high volume air sampler for monitoring pesticides and Polychlorinated Biphenyls in ambient air. Sampling module: This is composed of two parts (figure 7). Part 2 is on top, and is composed of a metal filter holder, supported by a 16-mesh stainless steel screen which is attached to a metal cylinder, part 1, holding a 65 mm outer diameter (60 mm internal diameter) x 125 mm borosilicate glass sorbent cartridge carrying the PUF. The filter holder is includes inert sealing gaskets at each side of the filter. Likewise, the glass sorbent cartridge is air tight sealed at each end, with inert pliable gaskets, mainly made of silicon rubber. The part 1 fits into the glass sorbent cartridge, screwed with part 2 until it is sealed between the silicon gaskets. In figure 2 is showed a typical assembly of the sampling module. Figure 8 shows a portable module designed by the EPA.
10
Figure 7. Adsorbent cartridge assembly for sampling common pesticides and Polychlorinated Biphenyls.
Figure 8. Portable high volume air sampler developed by EPA. 11
High volume sample calibrator: to provide multipoint resistance for the high volume sampler. Ice chest: to keep samples at <4o C or below during transportation to the laboratory after collection. Data sheets: to record all data in each sampling. Materials for sample collection are showed in figure 9.
Figure 9. Exemplary of materials employed in sample collection.
12
Calibration of sampling systems: Sampler should be calibrated: when new, after major repairs and maintenance, whenever a point deviates from the calibration curve more than 7%, before and after every sampling event, when different sampling media for which the sampler was calibrated to sample. The high volume sampling system can be calibrated using the calibrated orifice transfer standard, as it is showed in figure 10.
Figure 10. Set up of field calibration system of HVSs of pesticides and PCBs.
13
3.2.2.2
Sample clean-up and extraction
Soxhlet extractor (figure 11a): to extract filters and cartridges (2.3” x 5” length) in 1000 mL flask. Pyrex glass tube furnace system: to activate silica gel at 180o C with purified nitrogen gas purge for an hour. Glass vial: 40 mL Erlenmeyer flask: 50 mL. Reuse of glassware is not advisable, to avoid cross contamination. White cotton gloves: for handling cartridges and filters. Minivials: 2 mL, borosilicate glass. Teflon® coated stainless steel spatulas and spoons Kuderna –Danish (K-D) apparatus (Figure 11b): 500 mL evaporation flask, 10 mL concentrator tubes with ground glass stoppers and 3 ball macro Snyder column. Adsorption column for column chromatography (Figure 11c) Glove box: when working with extremely toxic standards, and explosive reagents. Vacuum oven: maintaining a vacuum at 240 torr overnight. Concentrator tubes and a nitrogen evaporation apparatus with variable flow rate. Laboratory refrigerator Boiling chips Water bath: capable of ±5 o C temperature control. Nitrogen evaporation apparatus. Glass wool
14
Figure 11. Apparatus used for sample clean-up and extraction.
3.2.2.3
Sample analysis
Gas chromatograph: equipped with appropriate detector and temperature controlled oven. Gas chromatograph column and all required syringes, gases and supplies to operate the GC. Microsyringes: 5 ÂľL volume or similar. Balance: Mettler balance or similar.
15
Pipetes, micropipettes, syringes, burets, etc.: to make calibrations and spiking solutions, dilute samples, etc. Organochlorine pesticides and non-chlorinated pesticides respond appropriately to electron capture detection (ECD). These compounds can be analyzed at concentrations of 1- 50 ng/ mL by GC- ECD. Detection limits range in 0.001 to 50 µg/ m3. This limit detection differs according to the nature of the substance and the length of sampling period. Typical operation injections with splitless injections are: carrier gas helium at a flow rate of 1-2 mL/ min, a column head pressure of 7 – 9 psi (48- 60 kPa), injector temperature of 250 o C, detector temperature of 350 o C, initial oven temperature of 50 o C held for 2 min., then ramped at 15 o C/ min. to 150 o C for 8 min., ramped at 10 o C/ min., to 295 o C for 5 min., purge time of 1 min. at a typical injection volume of 2-3 µL. In figure 12 is a typical ECD response for a mixture of single component pesticides, employing capillary column.
Figure 12. Chromatograph showing a mixture of single component pesticides, employing GC/ ECD with a capillary column.
16
3.2.2.4
Method TO 4A Parameters
Flow rates normally range from 200-280 L/ min, during a sampling time of 24 h. Detection limits range in 0.001 to 50 µg/ m3. This limit detection differs according to the nature of the substance and the length of sampling period. The pump pulls a sample volume greater than 300 m3, during the sampling period. Once the sampling is completed, the cartridges should be protected against UV – light, to avoid photo decomposition of the samples. During the transportation, the samples should be kept at a temperature lower than 4 oC, in the laboratory; they should be stored at ≤ 4 oC. Extraction must be done within 7 days after sampling and the analysis within 40 days of extraction. The samples should be extracted using Soxhlet employing 10% diethyl ether in hexane. Analysis executed with GC joined with an electron capture (ECD) or another appropriate detector.
Further and detailed description of materials and procedures can be found in the Method TO 4A.
3.3
Standardization of the measurement procedure
The Direction of Management of Ambient Quality (DIGECA, acronyms in Spanish) a department of the Ministry of Ambient, Energy and Telecommunications (MINAET, acronyms in Spanish) in Costa Rica, in the matter of air monitoring give a reference to the described methods of the Environmental Protection Agency (EPA) in the US. This is the reason that the method TO 4A was described in this plan.
3.4
Infrastructure for using measurement techniques
The measurements will be placed near to communities, to determine the exposure of inhabitants to concentration of pesticides, and also some emission sources will be includes. It will be assured that the selected sampling points offer a constant energy supply. In case of short-cuts, the equipment will be run with batteries. The sampling device is already equipped with a cover to protect against weather. There will be a personal in rotating times, for the supervision of the devices during the sampling period, to avoid any interference or manipulation. Besides, it will be assured to have replace parts in case of break down of instruments in order to reduce interruptions.
3.5
Data recording and documentation of the measured values
Sampling: in each episode, it is recorded the location and sample time, duration of sample, starting time and volume of air sampled. A typical data sheet for field data sheet is showed in figure 13. Calibration data sheet for field calibration is showed on figure 14. 17
Figure 13. Field test data sheet.
18
Figure 14. Orifice transfer standard field calibration data sheet.
19
4 Quality Assurance As part of the QA, technicians should elaborate Standard Operation Procedures (SOPs) describing the following activities: 1. Assembly, calibration, and operation of the sampling system. 2. Preparation, purification, storage, and handling of sampling cartridges. 3. Processing, including lists of computer hardware and software used.
The following references will be undertaken: 1. One filter/ PUF cartridge without shipment to the field as a process blank 2. One filter/ PUF cartridge after shipped to the field and without drawing air through the sampler, to serve as a field blank 3. Before each sampling episode, one PUF should be inoculated with a known amount of the standard solution, to indicate sample degradation 4. During the analysis of each batch of samples, at least one solvent process blank
The calibration is done with gas-meters, which is more practical and precise than Orifice Transfer Standard. It will be performed at the beginning of the sampling period, after 6 months and end of the period (also if reparation) Comparison samplings: at the beginning and the end: setting all 3 instruments in the same site and taking samples from each. Results should be the same in all of them.
20
5 Evaluation The measurement period is stipulated to last one year, with individual samplings in a weekly basis. The evaluation procedure is referred to the mean annual values and individual measurement results. At the moment, in Costa Rica limit values for the concentration of pesticides in the atmosphere still do not exist. The following calculations have been specified by the EPA method TO - 4A, further descriptions can be found in this document.
5.1
Detection limits
Detection limits of pesticides range in 0.001 to 50 Âľg/ m3, employing GC- ECD. As explained before, this limit detection differs according to the nature of the substance and the length of sampling period.
5.2
Calculation of pesticides in the air
Analytes concentration in the extract solution can be determined from a standard curve in which peak height or area is plotted linearly versus concentration in nanograms per milliliter (ng/mL). In order to determine the quantity of the measured compound in the sample, the following equation is employed:
(1) Where: A = total amount of analyte in the sample, ng. As = calculated amount of material injected onto the chromatograph based on calibration curve for injected standards, ng. Ve = final volume of extract, mL. Vi = volume of extract injected, ÂľL. 1000 = factor for converting microliters to milliliters. To determine the total volume of air sampled under ambient conditions, the following equation applies:
(2) Where: Va = total volume of air sampled, m3 Ti = length of sampling segment between flow checks, min. i 21
Fi = average flow during sampling segment, L/min. The calculated air volume is corrected to EPA temperature (25o C) and standard pressure 756 mm Hg as follows:
(3) Where: Vs = volume of air at standard conditions (25oC and 760 mm Hg), std. m3 Va = total volume of air sampled, m3 Pb = average ambient barometric pressure, mm Hg Pw = vapor pressure of water at calibration temperature, mm Hg TA = average ambient temperature, oC + 273. The concentration of the measured compound in standard cubic meter of air sampled is calculated with the following equation:
(4)
5.3
Method precision and bias
When using this type of analytical measurement, precision and bias rely on the analytical procedure for each compound of interest and the precision and bias of the sampling process. Different parameters are identified in these processes: when the sampled air volume is increased, the sensitivity of detection increases proportional in limits specified by: 1. retention efficiency for each particular component trapped on the polyurethane foam plug, and 2. background interference related with the analysis of each component in a specific sampling site. In terms of extraction, the sensitivity of detection of recovered samples depends on: 1. inner response of specific GC detector employed, and 2. the concentration of the sample under analysis. The analyst is responsible of adjusting parameters to obtain the required detection limits. The reproducibility of this method in most of the compounds for which this method has been tested, ranges between Âą5 to Âą30%, determined as relative standard deviation, when when replicate sampling cartridges are used (N>5). For individual compounds, there are recoveries in the range of 90 to 110%, but also in the range of 65-125% is acceptable.
22
5.4
Overall measurement uncertainty
The overall uncertainty of a measurement is the quantity employed to determine the general uncertainty of the result obtained by a measurement [16]; this is expressed in percentage using the following equation:
Where: OU = the overall uncertainty of the procedure = mean value of results of n repeated measurements = true or accepted reference value = standard deviation of n repeated measurements This overall uncertainty of procedures in the measurement of chemical agents in workplace air (immision measurement) should be lower than 50% for measurements in the range of 0.1 to 0.5 times the limit value.
5.5
Uncertainty of the results
In order to have a complete assessment of the results, information regarding the meteorological behavior, such like: mean rain intensity, wind speed and direction is required.
[16]
General requirements for the performance of procedures for the measurement of chemical agents. 1994.
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6 Organization For the execution of this project, the following personnel have been identified, which are described in the chart of the figure 15: 1. Project leader: This is the person in charge of the planning, leading and supervision of the project. This person will specify the methodology and procedure to execute the measurements. For this task, this should be a professional in the field of air quality control and air pollutants measurement; also, this person should have had experience in management and leadership of groups. 2. Technicians: It will be required personnel for the data collection in the field and also for the establishment of the equipment and calibrations, for this, these should be persons with experience in data field collection and air measurement techniques. It will be also required technicians for the laboratory analysis to determine the chemical composition of the pesticides in the samples and its compositions. These personnel should be experienced and skilled in laboratory techniques and GC equipment handling. 3. Statistician: It will be required a team for the evaluation and analysis of the data collected. For this, personnel in data analysis and a statistician can perform these tasks.
Project Leader
Technician: Data collection
Technician: Lab analysis
Evaluation: Data Analysis and Statistician
Figure 15. Personnel planning for the pesticide air monitoring in Limon, Costa Rica. 24
In the figure 16 is described the scheduling for the development of the measurements. This is designed to cover 1 year of sampling and also, it includes the time for preparation of the equipment and planning and also, the analysis and report of the data collected.
Figure 16. Scheduling for the measuring of pesticides in Limon, Costa Rica.
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7 Conclusion There is a high risk of pollution due to intensive use of pesticides in bananas cultivation in the Atlantic zone of Costa Rica. Their long residence time in the atmosphere and makes prone the accumulation of toxic substances in the environment. Modes and conditions of application of pesticides in bananasâ&#x20AC;&#x2122; fields play an important role in the drift and volatilization of pesticides into the atmosphere. It is important to keep track to the concentration and dispersion of pesticides in the atmosphere in order to limit the pollution and the risk of health impact on the communities around the plantations and even the same workers in these companies and also, to avoid environmental stresses. The Method EPA 4TO-A with active samplings is employed in short periods but with high frequency. This method provides accurate quantitative data and information regarding the particle phase and the gaseous phase conditions. It is important that the personnel involved in the measurement project is well trained and skilled to undertake the different tasks, and also, capable to follow the method and procedures involved for the samplings. Finally, the evaluation and quality assurance provide enough information on the accuracy and certainty of the results and measurements.
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8 References [1]. Central Intelligence Agency (CIA). [2012]. The World Fact book: Costa Rica. Searched: 06.09.12. [2]. Steiner, R. 2006. Utilización Energética de Residuos Orgánicos de la Industria Bananera, cafetalera y azucarera en Costa Rica: Considerando el Mecanismo de Desarrollo Limpio. Costa Rica. FHNW-GTZ. [3]. De los Santos, J., Pratt, L. and Pérez, M. 1997. Uso de plaguicidas en la Agroindustria de Costa Rica. CEN 708. [4]. Ramírez, J. and Lacasaña, M. 2001. Plaguicidas: clasificación, uso, toxicología y medición de la exposición. Universidad Pompeu Fabra. Arch Prev. Riesgos Labor 2001; 4(2):67-75. [5]. Wolters, A. 2003. Pesticide Volatilization from Soil and Plant Surfaces: Measurements at Different Scales versus Model Predictions. Doctorate dissertation. Rheinisch-Westfälischen Technischen Hochschule Aachen. [6]. Santamaria-Ulloa.2009. The Impact of Pesticide Exposure on Breast Cancer Incidence. Evidence from Costa Rica. Revista Población y Salud en Mesoamerica. Vol. 7, no. 1, art. 1. [7]. Organización Panamericana de la Salud. 2003. Efectos de los plaguicidas en la salud y el ambiente en Costa Rica. Ministerio de Salud. San José (CR). ISBN 92 75 32474 3. [8]. Shunthirasingham, C. et al. Current use pesticide transport to Costa Rica’s high altitude tropical cloud forest. Environmental Toxicology and Chemistry, Vol. 30, No. 12, pp. 2709–2717, 2011. [9]. Daly et al. 2007. Accumulation of Current Use Pesticides in Neotropical Montane Forests. Environ. Sci. Technol. 2007, 41, 1118-1123. [10]. Buckland, S. Ellis, H. and Salter, R. 1999. Organochlorines in New Zealand: Ambient Concentrations of Selected Organochlorines in air. Ministry of Environment. ISBN 0 478 09033 1. [11]. http://de.wikipedia.org/wiki/Costa_Rica [12]. http://www.windfinder.com/windstats/windstatistic_puerto_limon.htm [13]. Hayward, J. 2010. Fate of Current used pesticides in the Canadian Atmosphere. PhD dissertation. University of Toronto. [14]. Yusa et al. 2009. Sampling and analysis of pesticides in ambient air. Journal of Chromatography A, 1216 (2009), 2972-2983. [15]. Winberry, W., Riggin, R., Lewis, R. 1999. Compendium of methods for the determination of toxic organic compounds in ambient air: Compendium Method TO- 4A. Determination of Pesticides and Polychlorinated Biphenyls in Ambient Air Using High Volume Polyurethane Foam (PUF) Sampling followed by Gas Chromatographic/ Multidetector detection (GC/ MD). 2nd ed. U.S. Environmental Protection Agency. EPA/ 625/ R-96/010b. [16]. General requirements for the performance of procedures for the measurement of chemical agents. 1994. [auth.]. British standards Institution Workplace. ISBN 0580236447.
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9 Appendix Table 1. Technical package for field management in banana cultivation. * Indicates that the pesticide is currently banned in Costa Rica.
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