1.0 INTRODUCTION This Supplemental Expert Report responds to comments of Claimants, Chevron Corporation and Texaco Petroleum Company (hereafter collectively, Chevron), on my opinions contained in the Rejoinder Expert Report of Jeffrey W. Short, Ph.D. Regarding Activities and Environmental Conditions in the Former Texaco‐ Petroecuador Concession, Republic of Ecuador (hereafter Short December 2013 Rejoinder Report). I reaffirm my opinions expressed in my December 2013 Rejoinder Report, and provide additional evidence to support these opinions in this Supplemental Expert Report. In addition, I offer here supplemental opinions to address issues raised in the three rebuttal documents filed by Chevron listed above. * * * * 2.0 MATERIALS REVIEWED I have been retained by the Louis Berger Group, Inc. (hereafter Louis Berger) to review and comment on the above Chevron documents. I have also been retained to interpret data from the chemical analysis of soil, sediment and water samples collected by Louis Berger from oil contaminated sites in Chevron’s former Concession Area during the spring and summer of 2014. In preparation of this Supplemental Expert Report, I have reviewed the following:
Expert Opinion of John A. Connor, P.E., P.G., B.C.E.E. Regarding Remediation Activities and Environmental Conditions in the Former Petroecuador – Texaco Concession, Oriente Region, Ecuador, Response to LBG Report of December 2013, Issued 7 May 2014 (hereafter Connor May 2014 Response Report),
Second Expert Report by Robert E. Hinchee, Ph.D., P.E., Issued 9 May 2014 (hereafter Hinchee May 2014 Response Report),
The Matter of An Arbitration Under the Rules of the United Nations on International Trade law; Chevron Corporation and Texaco Petroleum Company, Claimants, v. The Republic of Ecuador, Respondent, Claimants’ Supplemental Memorial, Track 2, Issued 9 May 2014 (hereafter Claimants’ May 2014 Supplemental Memorial),
Louis Berger’s Supplemental Expert Report, Issued 7 November 2014,
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Preliminary results1 of chemical analyses for hydrocarbons produced by Axys Laboratory, Katahdin Laboratory, and Battelle Memorial Institute provided to me by Louis Berger,
all scientific literature and deposition documents cited herein,
numerous chemical analysis reports produced by Dr. Gregory Douglas at Newfields Environmental Forensics Practice, and associated chemical analysis reports produced by Alpha Woods Hole Group and Severn Trent Laboratories.
I am currently an independent consultant and have never been an employee of Louis Berger or of Winston & Strawn LLP. My opinions in this expert report are given to a reasonable degree of scientific certainty. They are based on my education, professional experience, information and data available in the scientific literature, and information and data about this lawsuit identified herein and in my earlier report. I continue to review available information, and I reserve the right to amend or supplement this report and the opinions contained in this report on the basis of any subsequently obtained material information. * * * * 3. SUMMARY OF SUPPLEMENTAL OPINIONS 3.1 Results from Louis Berger’s Sampling in 2014 Confirm My Previously Expressed Opinions: Measurement of total petroleum hydrocarbons by Method 8015B – the method employed and relied upon by Claimants’ experts ‐ detects less than 20% of the petroleum actually present in contaminated soils and sediments in former Concession Area oil fields. US EPA Method 418.1 was much more accurate for determining the extent of petroleum hydrocarbon contamination in former Concession Area oil fields than was Method 8015B. The weathering state of petroleum in samples collected in 2014 was little changed from samples collected in 2013, consistent with my prior opinion that petroleum weathering is now largely arrested in the former Concession Area. Given these results and the observed conditions of contamination, I do 1 As of the writing of this report the laboratories and Louis Berger had not yet completed validation of the 2014 sampling data.
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not believe that weathering will naturally remediate the contaminated areas to an appreciable extent within the next few decades. 3.2 Based on My Analysis of Results from Louis Berger’s Sampling in 2014, I Conclude the Following: The average natural background of organic material extractable with dichloromethane in soils and sediments of the former Concession Area is about 160 mg/Kg, and is almost certainly less than 400 mg/Kg, which is negligible for most concerns. The natural background for total polycyclic aromatic compounds (total PAC) in soils and sediments of the former Concession Area is most likely less than about 0.05 mg/Kg and almost certainly less than about 0.1 mg/Kg, The natural background for total petroleum hydrocarbons measured by Method 8015B (TPH8015) in soils and sediments of the former Concession Area is most likely about 50 mg/Kg and almost certainly less than 100 mg/Kg, When PACs and TPH8015 are detected above background concentrations the detected compounds were almost certainly derived from petroleum that was originally produced at the oil field where sampling occurred, Petroleum contamination in groundwater samples is predominantly present as whole, free‐phase oil rather than as compounds dissolved from petroleum. Most petroleum detected in the samples analyzed was only moderately weathered but still fluid at ambient temperatures within the former Concession Area, and could be readily dispersed into water and transported by groundwater. 3.3 Criticisms by Dr. Robert Hinchee of My Prior Reports are Without Merit: Contrary to Dr. Hinchee’s claims, the Toxicity Characteristic Leaching Procedure (TCLP) as applied in the former Concession Area was not intended to evaluate the mobility of free‐phase oil in soils and sediments, but TCLP was instead applied according to the procedure specified for evaluating dissolution of oil components into receiving water. The most important consequence of the flawed method used by Dr. Hinchee and Mr. Connor to evaluate oil weathering, that I pointed out in my previous report, is the greater fluidity implied by the less‐weathered oil, enabling it to be more readily transported in ground‐ and surface waters, not the effect this
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error had on their inferences regarding the solubilities of oil components, a relatively minor concern in comparison.
Dr. Hinchee objects to the weathering scale I used to evaluate the extent of weathering of petroleum‐contaminated samples, yet this is the very same scale used by Chevron’s own experts, on whose interpretations and reports Dr. Hinchee himself had previously relied. Also, Dr. Hinchee simply ignores fundamental principles of scientific inference when he concludes that the Louis Berger samples from 2013 show significant additional weathering compared with samples collected nearly a decade earlier for the Judicial Inspections.
3.4 Comparison of Toxic Polycyclic Aromatic Compounds in Petroleum from the Former Concession Area and Bunker Oil from the Prestige Oil Spill I compared distributions of relative PAC abundances in Bunker oil discharged during the Prestige oil spill off the Spanish coast in 2002 with un‐ weathered Shushufindi crude oil to confirm that they broadly shared the same suites of toxic PAC, which validates the relevance of toxicological studies performed after the Prestige oil spill to conditions in the former Concession Area. * * * * 4.0 SUPPLEMENTAL OPINIONS 4.1 Results From Louis Berger’s Sampling in 2014 Confirm My Previously Expressed Opinions Results from chemical analysis of samples collected from the former Concession Area during Louis Berger’s 2014 sampling campaign confirm opinions I set forth in my previous report2. Some of the collected soil and sediment samples were analyzed by three methods: (1) USEPA Method 8015B for “total petroleum hydrocarbons” (TPH, hereafter denoted as TPH8015), (2) gravimetrically for total extractable material (TEM) based on dichloromethane extraction (which I recommended in my earlier report3), and (3) USEPA Method 8270 for polycyclic aromatic compounds (PAC), alkanes and petroleum biomarkers. These analyses were performed on portions of the same samples so that the results are directly comparable. The results corroborate several conclusions in my previous report4. 2 Short December 2013 Rejoinder Report 3 Ibid. 4 Ibid.
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The gravimetric TEM method is especially simple, involving extraction of petroleum into dichloromethane, separation of the extract from soil or sediment particles by filtration, evaporation of the dichloromethane and weighing the petroleum residue left behind. This gravimetric TEM method is an adaptation of US EPA Method 413.1, Oil and Grease (gravimetric, separatory funnel extraction)5. The adaptations include: (1) use of dichloromethane as the extraction solvent instead of the now banned trichlorotrifluoroethane specified in Method 413.1; and (2) application to soils and sediments. This method for gravimetric determination of TEM was successfully used to quantitatively determine residual petroleum on beaches of Prince William Sound, Alaska, 12 years after the petroleum was deposited by the 1989 Exxon Valdez oil spill6. These and other closely related methods, including US EPA Method 418.17, ASTM D7066‐048, and APHA Standard Method 5520B and 5520C9 all use chemically similar extraction solvents into which petroleum can dissolve completely, and use detection methods that can detect all the low‐volatility components of petroleum (i.e. by infrared spectroscopy or by gravimetric weighing)10, so they produce closely comparable results. Comparison of TEM results with TPH8015 results confirms that Method 8015B detects less than 20% of the petroleum actually present in samples of soils or sediments. This finding is illustrated in Figure 1, where results for TPH8015 are plotted against the gravimetrically‐determined TEM. The regression line coefficient r2 of 0.96 indicates that the gravimetric TEM measurement accounts for 96% of the variation in the TPH8015 measurements. The regression line slope of 0.189 indicates that Method 8015B detects about 19% of the petroleum actually present. At lower levels of petroleum contamination, this regression slope decreases to 0.124, indicating detection of only 12% of the petroleum actually present, consistent with the trend toward greater weathering in less contaminated soils and sediments noted in my earlier reports11. This finding is expected because Method 8015B 5 see http://www.cromlab.es/Articulos/Metodos/EPA/400/413_1.PDF 6 Short JW, Lindeberg MR, Harris PM, Maselko JM, Pella JJ, and Rice SD (2004) Estimate of oil persisting on the beaches of Prince William Sound 12 years after the Exxon Valdez oil spill. Environmental Science and Technology 38:19‐25 7 This method was discontinued by EPA because vapors from the trichlorotrifluoroethane used as the extraction solvent depletes atmospheric ozone. 8 American Society for Testing and Materials International Method D7066‐04 is a replacement method for EPA Method 418.1 and uses chlorotrifluoroethylene, 9 The American Public Health Association Standard Method 5520 for oil and grease determination provides for both gravimetric (Method 5520B) and infrared (Method 5520C) detection of oil and grease extracted from samples; see http://www.standardmethods.org/store/ProductView.cfm?ProductID=41 10 American Petroleum Institute Publication Number 4709 (2001), Risk‐based methodologies for evaluation petroleum hydrocarbon impacts at oil and natural gas E&P sites, p. 35 11 Short December 2013 Rejoinder Report; Expert Opinion of Kenneth J. Goldstein, M.A., CGWP and Jeffrey W. Short, Ph.D. Regarding the Environmental Contamination
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cannot detect a substantial fraction of the crude oil present, for reasons stated in my earlier report12. Moreover, this undetected fraction increases as crude oil weathers following release into the environment. These results also corroborate the greater than 4:1 DRO:TPH relationship between Method 8015B and TPH as determined by USEPA Method 418.1 and discussed in our first report.13
Figure 1. Comparison of TPH8015 and TEM by gravimetric extraction in soil and sediment samples collected from the former Concession Area during spring and summer 2014. Furthermore, the PACs found in the samples indicate that the TEM in these samples is almost always weathered crude oil. This finding is illustrated in Figure 2, where results for total PAC are plotted against the gravimetrically‐determined TEM. The regression line coefficient r2 of 0.65 indicates that the gravimetric TEM measurement accounts for 65% of the variation in the total PAC measurements. The regression line slope of 0.00528 indicates that on average the weathered crude oil in the samples collected contained about 0.53% total PAC, compared with 0.85% From Texpet’s E&P Activities in the Former Napo Concession Area Oriente Region, Ecuador” (hereafter Louis Berger, 2013) 12 Short December 2013 Rejoinder Report 13 Louis Berger, 2013, p. 35‐37
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typical of un‐weathered Oriente crude oils.14 Concentrations of total PAC that were lower than expected on the basis of the gravimetric TPH are almost certainly the result of weathering losses. The weaker association of total PAC with gravimetric TEM (65%) in comparison with the TPH8015 by Method 8015B and gravimetric TEM (96%) mainly reflects the greater susceptibility of PACs to weathering losses in comparison with crude oil components measured by Method 8015B.
Figure 2. Total PAC concentrations in soil and sediment samples collected from the former Concession area during spring and summer 2014. These strong correlations between TPH8015 by Method 8015B and total PAC with gravimetric TEM indicates that concerns raised by Chevron’s experts that Method 418.1 is susceptible to serious positive interferences from naturally occurring organic compounds in environmental samples are considerably overstated. As I noted in my previous report15, substantial interferences of this sort are unlikely based on simple mass balance considerations. Results from the Louis Berger 2014 samples corroborate this view. Substantial interferences from natural sources of organics would be evident in anomalously high concentrations of PAC or alkane hydrocarbons, with abundance distributions differing markedly from those typical 14 Alpha Woods Hole Group, laboratory sample number 0406054‐01 at GSD305171, identified as Shushufindi Suroeste oil at GSD 207000 (hereafter GSD305171) 15 Short December 2013 Rejoinder Report
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of petroleum, and that are associated with higher concentrations of gravimetric TEM. Instead, the strong association of TPH measured by Method 8015B and TPH measured gravimetrically as TEM (Fig. 1) shows that contributions of organics from unknown, natural sources are generally negligible in the Oriente, especially after making appropriate allowance for weathering on the Method 8015B results. Finally, gravimetric TEM concentrations in soils or sediments above about 2,000 mg/Kg are accompanied by biomarker distributions characteristic of Oriente crude oils, and concentrations above 1,000 mg/Kg are almost always associated with PAC abundance distributions characteristic of crude oil. These results corroborate the argument I presented in my earlier report16 that interference from natural sources is negligible in comparison to crude oil contamination above 1,000 mg/Kg. Consequently, results based on Method 418.1 should not be dismissed on the basis of speculative assumptions, now clearly shown to be incorrect, and especially not in deference to Method 8015B, which is shown to be susceptible to far worse bias towards false negative results. 4.2 Genetic Relationships Among Petroleum Contaminants The petroleum biomarker fingerprints are remarkably constant throughout the samples analyzed, based on 16 diagnostic biomarker ratios recommended for fingerprinting crude oils17 (Table 1). This indicates that all of the soil and sediment samples analyzed for petroleum biomarkers have crude oil sources, most likely from their respective oil fields. The slight departures that do occur from the overall biomarker fingerprint are most likely the combined result of varying susceptibility to alteration through weathering processes and variation associated with low biomarker concentrations as detection limits are approached, although comparison of two diagnostic ratios suggest real differences in the biomarker fingerprints characterizing the Aguarico and Shushufindi oil fields (Table 1). Conversely, there is scant evidence of the presence of petroleum from sources outside the Oriente oil fields of Ecuador. Results for diagnostic biomarker ratios are listed in Table 1 for soil and sediment samples containing at least 2,000 mg/Kg TEM as measured by the gravimetric method to ensure sufficient biomarker concentrations for accurate determinations of all the constituent biomarkers used to calculate the ratios detected. Table 1. Petroleum hydrocarbon biomarker used for computation of 16 diagnostic ratios and their ranges in soil and sediments at each of the three former Concession Area oil fields sampled during spring and summer 2014. Numbers in parentheses following the oil field labels indicate the number of samples included for 16 Ibid. p. 14 17 Daling PS, Faksness LG, Hansen AB and Stout SA (2002) Improved and standardized methodology for oil spill fingerprinting. Environmental Forensics 3:263�278
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determination of the range for each oil field. Biomarker ranges in boldface indicate potential differences in the biomarker fingerprints of crude oils from the Aguarico compared with the Shushufindi oil fields.
4.3 Weathering State of Petroleum Contamination Most samples collected by Louis Berger in 2014, whether soils, sediments or groundwater, contained petroleum at the Kaplan and Galperin (1996)18 weathering index of 5, indicated by extensive losses of volatile compounds and of n‐alkanes, but only slight to modest losses of PACs, mainly naphthalenes (Tables 2 – 4). Several samples were more weathered, having weathering indexes of 6 or 7, indicated by more extensive losses of PACs. However, some samples had a weathering index of 4, indicated by loss of most n‐alkanes but of scant PACs. Two samples, collected from the same bore hole at SSF‐13, had a weathering index of 2, retaining all but the lightest n‐alkanes, suggesting the oil was either remarkably well preserved, or more likely was spilled relatively recently. As expected, the petroleum contaminating stream sediments is generally more weathered than petroleum in soils. The weathering index for stream sediments is often 6 or 7, whereas it is usually 5 and sometimes 4 or less in soils. Weathering indexes could often be assigned to the more contaminated groundwater and surface water samples, and when assigned were usually 5 or 6.19 18 Kaplan, I.R., Galperin, Y., Alimi, H, Lee, R.P., and Lu, S.T. 1996, Patterns of Chemical Changes during Environmental Alteration of Hydrocarbon Fuels, Groundwater Monitoring and Remediation 113 – 114 (hereafter Kaplan and Galperin 1996) 19 Weathering states were assigned when total PAC exceeded 0.5 mg/Kg in soils or stream sediments, or exceeded 0.5 ug/L in groundwater or surface water samples. These thresholds for assigning weathering states do not reflect thresholds for the
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Overall, the samples collected during the 2014 sampling campaign show little indication of additional weathering since the previous sampling campaign conducted by Louis Berger in 2013. The samples taken in 2014 further confirm my conclusion that weathering has been largely arrested for oil contamination in the Oriente. As I discussed in my 2013 Reports20, this is most likely because the petroleum has been buried where oxygen and other conditions conducive for weathering are largely absent. To be clear, I have never opined that no weathering has occurred. Weathering can substantially change the composition of petroleum on time scales that range from hours to hundreds of years or more, in which latter case the weathering rate becomes “largely arrestedâ€?21. I recognize that some weathering has occurred and continues to occur, but mostly at rates that are now negligible over the course of years to decades. As a result, while some volatile fractions of crude oil are no longer present, other toxic and carcinogenic components, like PACs, are still present in substantial concentrations. Given these results and the observed conditions of contamination, I do not believe weathering will naturally remediate the contaminated areas to an appreciable extent within the next few decades. 4.4 Interpretation of Hydrocarbon Analyses of Field Samples Collected from Ecuador in 2014 4.4.1 Amount and Extent of Petroleum Contamination Although concentrations varied widely among the samples collected, indications of heavy petroleum contamination were evident at all three of the Oriente oil fields (Shushufindi, Lago Agrio and Aguarico) where samples were collected and analyzed for petroleum hydrocarbons. Lower concentrations of oil contamination in soil, sediments, and groundwater were also evident at these sites. In contrast, PAC evidence of surface water contamination by petroleum was evident only in water samples from the Lago Agrio field, and the concentrations were modest (i.e. less than 2.2 ď g/L total PAC22, or parts per billion). Most of the petroleum hydrocarbons in the samples are present as whole oil, meaning oil as a distinct phase separate from water, rather than as components of natural background of hydrocarbons in soils, sediments or groundwaters of the former Concession Area soils. The natural background concentrations are considerably lower. 20 Louis Berger, 2013, Short December 2013 Rejoinder Report 21 Louis Berger, 2013, p. 61 22 Total PAC refers to the sum of 48 parent polycyclic aromatic compounds, PAC, and classes of alkylated PAC, ranging from naphthalene with two aromatic rings through benzo[g,h,i]perylene with six. Excepting dibenzothiophene and the alkylated dibenzothiophenes, the other PAC are all polycyclic aromatic hydrocarbons, or PAH.
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oil dissolved into water. This association with whole oil is indicated by the concurrent presence of aliphatic hydrocarbons, especially pristane and phytane, which are relatively persistent branched alkane hydrocarbons, along with PAC. This evidence supports the conclusion that whole oil is migrating through or along with ambient media. 4.4.2 Shushufindi Samples collected from the Shushufindi oil field contained some of the most and least contaminated samples of the 2014 sampling campaign (Table 2). The lowest concentration samples serve to indicate the background concentrations of total PAC, n‐alkanes, TPH8015 and gravimetric TEM in the region. The highest concentration samples include the least‐weathered samples analyzed. Table 2. Summary of hydrocarbon analyses for samples collected during spring and summer 2014 from Shushufindi oil field, Ecuador. Analytical results are presented as mg/Kg for soils and sediments and ug/L for water samples, all given with two significant figures. Site
Total PAC
Soils SSF13‐SL001 SSF13‐SL002 (1)25 SSF13‐SL003 SSF13‐SL004 (2) SSF13‐SL005 SSF13‐SL006 SSF13‐SL007 SSF13‐SL008 SSF13‐SL009 SSF13‐SL010 SSF13‐SL011 (3) SSF13‐SL012 (4) SSF13‐SL013 (1) SSF13‐SL015 (3) SSF13‐SL016 (4) SSF13‐SL017 (2) SSF25‐SL029 SSF34‐SL001 SSF34‐SL002
0.021 0.027 0.030 0.026 0.032 0.020 0.69 0.022 0.036 1.85 650 2.0 660 0.028 0.025 0.052 0.040
Total n‐ Alkanes 0.55 0.77 1.3 0.53 0.27 0.22 2.7 0.40 0.47 2300 1.2 2500 0.36 0.28 0.48 0.33
TEM
TPH by 8015B
400 100 120 92 140 250 760 80 80 100 19,000 710 330
26 28 10 41 9 27 39 9 9 47 9,700 90 23
560
86
100 640 110
10 87 15
Weathering Diagnostic State23 Biomarkers24 NA NA NA NA NA NA 5 NA NA 5 2 Y 5 NA 2 NA NA NA NA
23 Weathering state is based on Kaplan & Galperin 1996. 24 Diagnostic biomarker symbols “Y” indicates a definite petroleum biomarker fingerprint consistent with the pattern presented in Table 1 above; “Y‐“ indicates a biomarker fingerprint indicative of petroleum but probably altered by weathering. 25 Numbers in parentheses following the site identification labels in column 1 indicate field duplicate samples.
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Site SSF34‐SL003 SSF34‐SL004 SSF34‐SL006 SSF34‐SL007 SSF34‐SL008 SSF34‐SL009 SSF34‐SL010 SSF34‐SL011 SSF34‐SL012 SSF43‐SL001 Sediments SSF13‐SE001 SSF13‐SE002 SSF13‐SE003 SSF13‐SE004 (5) SSF13‐SE006 SSF13‐SE007 SSF13‐SE008 SSF13‐SE009 SSF13‐SE010 SSF13‐SE011 (5) SSF55‐SE001 (6) SSF55‐SE002 SSF55‐SE003 SSF55‐SE004 SSF55‐SE005 SSF55‐SE006 SSF55‐SE007 SSF55‐SE008 SSF55‐SE009 (6) Groundwater SSF13‐GW001 SSF13‐GW002 (7) SSF13‐GW003 SSF13‐GW004 SSF13‐GW005 (7) SSF25‐GW008 SSF25‐GW009 SSF25‐GW010 SSF25‐GW011 SSF34‐GW001 (8) SSF34‐GW002 SSF34‐GW003 SSF34‐GW004 SSF34‐GW005 (8) SSF43‐GW002 SSF43‐GW003
Total PAC 0.054 0.051 0.083 0.076 0.068 4000 630 780 0.91 15 0.048 0.075 1.2 1.4 2.6 0.65 0.86 1.7 0.74 2.0 900 240 3.3 250 80 0.87 18 150 410 0.75 0.44 0.52 0.32 0.53 0.25 0.19 83 11 0.19 0.22 0.28 0.23 0.17 0.18 3.4
Total n‐ Alkanes 0.20 0.55 0.90 1.4 0.61 410 63 71 1.7 31 0.40 13 9.3 9.9 38 8.6 13 33 3.0 17 211 65 9.3 76 60 11 77 69 85 12 2.4 3.5 3.1 3.4 7.9 1.7 11 1.9 7.6 21 46 21 5.9 1.9 3.1
TEM 120 130 120 360 1,700 140,000 33,000 40,000 150 2,300
TPH by 8015B 15 17 38 25 24 53,000 7,000 11,000 80 1,200
930 26,000 880 39,000 1,500 2,200 1,100 2,000 320 11,000 53,000 11,000 2,700 53,000 30,000 1,800 22,000 50,000 23,000
12 30 75 460 77 100 54 140 27 330 14,000 5,000 230 6,500 2,800 120 5,000 5,900 6,900
130 130 200 39 150 210 39 2,100 1,100 53 55 61 110 43 140 210
Diagnostic Weathering Biomarkers24 State23 NA NA NA NA NA 4 Y 4 Y 4 Y 5 4 Y NA NA 7 7 Y‐ 7 7 Y‐ 7 7 Y‐ 6 6 Y‐ 5 Y 5 Y 5 Y 5 Y 5 Y 7 5 Y 5 Y 5 Y 6 NA 5 NA 6 NA NA 5 6 NA NA NA NA NA NA 5
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Site
Total PAC
Surface Water SSF13‐SW001 SSF13‐SW002 SSF13‐SW003 SSF13‐SW004 SSF13‐SW005 SSF13‐SW006 SSF13‐SW007 SSF13‐SW008 SSF13‐SW009 SSF13‐SW010
0.22 0.21 0.13 0.25 0.068 0.076 0.26 0.076 0.13 0.12
Total n‐ Alkanes 0.56 0.94 0.41 0.41 0.73 0.83 8.6 1.3 4.3 1.4
TEM
TPH by 8015B
62 30 35 110 33 60 100 62 90 140
Diagnostic Weathering Biomarkers24 State23 NA NA NA NA NA NA NA NA NA NA
4.4.2.1 SSF‐13
Most of the Shushufindi soil and sediment samples were collected from this site. Of the 14 soil samples collected and analyzed for PAC, 9 had very low concentrations of total PAC ranging from 0.021 – 0.036 mg/Kg (parts per million; Table 2). This concentration range for total PAC most likely reflects the natural PAC background of soils and sediments in the region. This natural background pattern of PAC abundance is depicted in Fig. 3, and is characterized by relatively little increase of alkyl‐substituted PAC abundance in comparison with the respective un‐substituted parent PAC of a homologous series, in contrast to soils contaminated with low concentrations of petroleum. Petroleum contamination in the LA16‐SL002 sample is indicated by the increased abundances of the alkyl‐substituted PAC in comparison with respective un‐substituted parent PAC, by the presence of chrysene and the alkyl‐substituted chrysene homologues, and the low abundances of the unsubstituted 5‐ring PAH (i.e. BBF, BKF, BEP, BAP, GHI, DA and IND).26 The comparison depicted in Fig. 3 suggests that the upper limit for the natural PAC background lies between 0.040 mg/Kg and 0.16 mg/Kg total PAC. The TPH8015 concentrations corresponding to this PAC background are less than 50 mg/Kg (Table 2), suggesting that the natural background for TPH8015 is almost certainly less than twice this concentration (i.e. 100 mg/Kg). Similarly, the TEM concentrations corresponding to the PAC background range from 80 – 400 mg/Kg, with an average of 160 mg/Kg. 26 Abbreviations for these compound classes are as follows: N=naphthalene, B=biphenyl, AY=acenaphthylene, AE=acenaphthene, B=biphenyl, F=fluorene, A=anthracene, P=phenanthrene, D=dibenzothiophene, FL=fluoranthene, PY=pyrene, BA=benzo[a]anthracene, C=chrysene, BBF=benzo[b]fluoranthene, BFK=benzo[k]fluoranthene, BEP=benzo[e]pyrene, BAP=benzo[a]pyrene, BP=benzopyrenes, PER=perylene, IND=indenopyrene, DA=dibenzoanthracene, GHI=benzoperylene; numbers following PAH abbreviations indicate the number of carbon atoms of alkyl substituents.
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Figure 3. Distribution of background PAC in soil (blue bars) compared with a soil sample (LA16‐SL002) containing a low level of contamination by petroleum (red bars). Soil samples from three other sites at SSF‐13had total PAC concentrations that ranged from 0.69 – 2.0 mg/Kg of total PAC. However, two soil samples, collected from the same bore hole inside the reserve pit (i.e. SSF13‐SL011 and –SL‐015), had total PAC concentrations of about 650 mg/Kg, associated with a total n‐alkane concentration of 2,300 – 2,500 mg/Kg, a TEM of 19,000 mg/Kg (or 1.9%) and a biomarker fingerprint indicating contamination by petroleum. The weathering state of these samples was 2, indicating loss of volatile alkanes and aromatics but little else. Comparison of the ratio of pristane to n‐heptadecane, or of phytane to n‐ octadecane shows little difference from respective ratios of un‐weathered Shushufindi crude oil, indicating little biodegradation has occurred. These results strongly suggest that petroleum was recently (less than a year) discharged to the soil that was sampled. Only 2 of the 10 samples of stream sediments from the SSF‐13 site contained background concentrations of total PAC, one at 0.048 and the other at 0.075 mg/Kg. Concentrations in the remaining 8 samples ranged from 0.65 to 2.6 ug/g, indicating low but clear contamination by petroleum.
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Total PAC concentrations in the 5 groundwater samples analyzed from SSF‐13 ranged from 0.32 – 0.750 ug/L (i.e. parts per billion). While low, these concentrations indicate clear contamination of the sampled groundwater by petroleum, confirmed by the concurrent presence of pristane and phytane. Total PAC concentrations in the 10 surface water samples analyzed from SSF‐13 ranged from 0.068 – 0.26 ug/L, with PAC distributions indicative of petroleum contamination. 4.4.2.2 SSF‐25 This site was more extensively analyzed in 2013 and my overall conclusions as relate to this site are included in my December 2013 Report. I maintain those conclusions. Limited sampling was conducted in 2014 at this site which I discuss below. The single soil sample analyzed from the SSF‐25 site contained only the background concentration of total PAC (i.e. 0.025 mg/Kg). Concentrations of total PAC in 2 of the 4 groundwater samples collected from the SSF‐25 site were 0.19 and 0.25 ug/L, and as with surface water samples at SSF‐13, have PAC distributions indicative of petroleum contamination. Two other samples contained total PAC concentrations of 11 and 83 ug/L, indicating clear contamination of the sampled groundwater by petroleum, confirmed by the concurrent presence of pristane and phytane. 4.4.2.3 SSF‐34 Seven of the 11 soil samples from SSF‐34 contained background concentrations of total PAC, ranging from 0.028 – 0.083 mg/Kg, with corresponding concentrations of TPH8015 ranging from 15 – 87 mg/Kg. Although corresponding TEM concentrations were usually less than 400 mg/Kg, one sample (SSF‐34 SL008) had a TEM concentration of 1,700 mg/Kg, despite concentrations of total PAC and TPH8015 of 68 mg/Kg and 24 mg/Kg, respectively. This sample was collected from 3.3 m depth near a pit, and inspection of the Method 8015B chromatogram revealed an unusual broad, large peak spanning a retention time window of nearly a minute, suggesting a possible contaminant associated with a product used by oil‐production operations, which are often proprietary. One sample (SSF‐34 SL012) contained low (0.91 mg/Kg) total PAC that was clearly derived from petroleum, and the other 3 were heavily contaminated by petroleum, with total PAC concentrations ranging from 630 mg/Kg to 4,000 mg/Kg. In addition to a PAC abundance distribution typical of petroleum contamination, the biomarker fingerprint provides additional confirmation of the petroleum source for these samples. The sample from SSF34‐SL009 was the most contaminated of all the soil
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and stream sediment samples collected from the Shushufindi oil field, and with TEM at 140,000 mg/Kg (or 14%) implies soil that is near or at saturation with petroleum. No stream sediment samples were analyzed from SSF‐34. The 5 groundwater samples analyzed from SSF‐34 contained total PAC concentrations ranging from 0.17 – 0.28 ug/L, generally consistent with the low‐ level petroleum contamination PAC pattern depicted in Fig. 3. 4.4.2.4 SSF‐43 The single soil sample analyzed from SSF‐43 contained a concentration of 15 mg/Kg total PAC, indicating moderate petroleum contamination and confirmed by the biomarker fingerprint. One of the 2 groundwater samples contained a total PAC of 0.18 ug/L, generally consistent with the low‐level petroleum contamination PAC pattern depicted in Fig. 3. The other sample contained 3.4 ug/L, indicating moderate petroleum contamination. 4.4.2.5 SSF‐55 Only stream sediment samples were analyzed from SSF‐55. Most of these were heavily contaminated by petroleum. Of the 9 samples analyzed, 7 had total PAC concentrations ranging from 80 mg/Kg to 900 mg/Kg, while the other 2 samples had concentrations of 0.87 and 3.3 mg/Kg, indicating moderate petroleum contamination. All of these samples except the one containing 0.87 mg/Kg total PAC had positive biomarker fingerprints consistent with oil contamination found elsewhere in the Shushufindi oil field. 4.4.3 Lago Agrio Petroleum contamination was evident in analyzed samples of soil, stream sediments, groundwaters and surface waters from the Lago Agrio sites (Table 3). The overall pattern and distribution of results is similar to those at the Shushufindi field.
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Table 3. Summary of hydrocarbon analyses for samples collected during spring and summer 2014 from Lago Agrio oil field, Ecuador. Analytical results are presented as mg/Kg for soils and sediments and ug/L for water samples, all given with two significant figures. Site Soils LA02‐SL022 LA02‐SL023 LA02‐SL024 LA16‐SL001 LA16‐SL002 LA16‐SL003 LA16‐SL004 (1)29 LA16‐SL005 LA16‐SL006 LA16‐SL007 LA16‐SL008 LA16‐SL009 LA16‐SL010 LA16‐SL011 (2) LA16‐SL012 LA16‐SL014 (2) LA16‐SL015 (1) Sediments LA35‐SE001 LA35‐SE002 LA35‐SE003 LA35‐SE004 LA35‐SE005 Groundwater LA16‐GW001 LA16‐GW002 LA16‐GW003 LA16‐GW005 LA02‐GW007 LA02‐GW008 LA02‐GW009 (3)
Total PAC 0.98 35 1.2 130 0.16 0.16 9.1 0.072 0.069 23 0.22 0.63 0.86 0.91 0.95 9.7 270 600 36 4.5 2.4 66 0.32 0.24 0.30 2.1 3.8 42
Total n‐ Alkanes
TEM
1.9 18 18 18 2.7 1.2 7.9 1.1 0.12 0.66 1.3 2.4 1.4 4.0 456 71 19 5.8 6.9 7.3 15 2.8 2.4 6.5 1.9 6.1
130
TPH by 8015B
7,600 1,800 300 520 130 590 2,500 91 220 200 320 92 260
44 2,800 130 2,400 15 8 280 14 10 710 12 55 37 41 75 90
88,000 29,000 14,000 9,000 44,000
5,200 6,500 5,400 570 320
1,100 78 130 72 290 110 91
Diagnostic Weathering Biomarkers28 State27 5 6 6 5 Y NA NA Y? 5 Y NA NA 5 Y NA 5 Y? 5 Y? 5 Y? 6 Y? 5 5 Y 5 Y 6 Y 6 Y 7 Y 5 NA NA NA 6 5 5
27 Weathering state is based on Kaplan & Galperin 1996 28 Diagnostic biomarker symbols “Y” indicates a definite petroleum biomarker fingerprint consistent with the pattern presented in Table 1 above; “Y?“ indicates a biomarker fingerprint indicative of petroleum but with the least abundant biomarker compounds not detected. 29 Numbers in parentheses following the site identification labels in column 1 indicate field duplicate samples.
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Site LA02‐GW010 LA02‐GW011 LA02‐GW012 (3) Surface Water LA35‐SW002 LA35‐SW003 (4) LA35‐SW004 LA35‐SW005 LA35‐SW006 (4)
Total PAC 200 0.070 42 0.82 0.49 2.2 1.86 0.72
Total n‐ Alkanes 32 2.1 6.0 4.3 3.8 17 2.3 1.8
TPH by 8015B 2,000 61 780
67 82 55 2,700 190
TEM
Diagnostic Weathering Biomarkers28 State27 5 NA 5 5 NA 5 6 6
4.4.3.1 LA‐02 This site was more extensively analyzed in 2013 and my overall conclusions as relate to this site are included in my December 2013 Report. I maintain those conclusions. Limited sampling was conducted in 2014 at this site which I discuss below. Two of the 3 soil samples analyzed for PAC from LA‐02 had low but clear levels of petroleum contamination, with total PAC concentrations of 0.98 and 1.2 mg/Kg. Petroleum contamination in the third sample analyzed was heavy, with the concentration of total PAC at 35 mg/Kg. Biomarkers were not analyzed in this sample because of insufficient sample mass collected for all the analyses to be performed. Petroleum contamination of groundwater at LA‐02 was also clearly evident. While 1 sample contained a background concentration of total PAC at 0.070 ug/L, concentrations in the other 5 samples ranged from 2.1 ug/L to 200 ug/L, and 3 of the 5 samples had concentrations above 40 ug/L. Elevated concentrations of pristane and phytane indicate this contamination was mainly present as whole, free‐ phase oil. The hydrocarbons detected in these 5 samples were sufficiently abundant that weathering states could be assigned, all of which were 5. 4.4.3.2 LA‐16 Four of the 13 soil samples analyzed for PAC from LA‐16 had moderate or heavy levels of petroleum contamination. The highest total PAC concentration was 130 mg/Kg, followed by 23 mg/Kg in another sample and concentrations above 9 mg/Kg in the remaining two. Another 5 soil samples had low but clear petroleum contamination, with total PAC concentrations ranging from 0.63 – 0.95 mg/Kg. Petroleum in most of these samples was confirmed by biomarker fingerprints. The remaining 4 samples had total PAC concentrations near or at the natural background, ranging from 0.069 – 0.16 mg/Kg.
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Of the 4 groundwater samples analyzed for PAC, one was heavily contaminated by petroleum, with a total PAC concentration of 66 ug/L at a weathering state of 5. Concentrations in the other 3 samples ranged from 0.24 – 0.32 ug/L, and consisted of PAC distributions depicted in Fig. 3 as indicative of low‐level petroleum contamination. 4.4.3.3 LA‐35 Only stream sediment and surface water samples were analyzed for PAC from LA‐ 35. Of the 5 stream sediment samples, the highest concentration of total PAC was 600 mg/Kg, followed by another sample containing 270 mg/Kg. A third sample contained about 36 mg/Kg, all indicating heavy petroleum contamination. The remaining two samples contained 2.4 and 4.5 mg/Kg, indicating modest petroleum contamination. Petroleum contamination in all these samples was confirmed by the biomarker fingerprints, and the weathering states ranged from 5 to 7, the latter indicating very weathered oil. All 5 of the surface water samples analyzed for PAC contained elevated concentrations indicative of petroleum contamination, ranging from 0.49 ug/L to 2.2 ug/L. 4.4.4 Aguarico As with the samples from Lago Agrio, samples from the Aguarico oil field sites reflect the general pattern of petroleum contamination in the region (Table 4). Table 4. Summary of hydrocarbon analyses for samples collected during spring and summer 2014 from Aguarico oil field, Ecuador. Analytical results are presented as mg/Kg for soils and sediments and ug/L for water samples, all given with two significant figures. Site
Total PAH
Soils AG04‐SL001 AG04‐SL002 AG06‐SL001 AG06‐SL002 AG06‐SL003 AG06‐SL004 AG06‐SL005
3285 2894 7.7 0.18 0.15 0.35 12
Total n‐ Alkanes 1362 1137 5.7 1.9 1.2 7.8 12
TEM 690,000 590,000 890 150 2,100 300 3,600
TPH by 8015B 120,000 120,000 230 18 16 26 360
Diagnostic Weathering Biomarkers31 State30 5 Y 5 Y 5 Y? NA Y? NA Y? NA Y? 5 Y
30 Weathering state is based on Kaplan & Galperin 1996 31 Diagnostic biomarker symbols “Y” indicates a definite petroleum biomarker fingerprint consistent with the pattern presented in Table 1 above; “Y?“ indicates a biomarker fingerprint indicative of petroleum but with the least abundant biomarker compounds not detected.
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Site AG06‐SL006 AG06‐SL007 AG06‐SL008 AG06‐SL009 Sediments AG06‐SE001 AG06‐SE002 AG06‐SE003 AG06‐SE004 AG06‐SE005 Groundwater AG06‐GW005 AG06‐GW007 AG06‐GW008 AG06‐GW009 AG06‐GW010 AG06‐GW011 Surface Water AG06‐SW001 AG06‐SW002 AG06‐SW003 AG06‐SW004 AG06‐SW005
Total PAH 31 13 126 75 0.52 2.1 0.59 0.33 0.63 5.5 0.60 26 3.2 214 7.2 0.091 0.078 0.10 0.094 0.089
Total n‐ Alkanes 11 6.7 20 29 2.7 4.2 11 5.8 6.6 4.5 10 21 86 13 1.0 9.7 0.51 0.48 0.85
TEM 2,000 2,500 14,000 6,800
TPH by 8015B 580 390 2,300 1,600
1,000 2,200 1,900 780 740
66 100 34 34 31
130 220 2,800 320 3,500 490
42 39 40 40 50
Diagnostic Weathering Biomarkers31 State30 5 Y 5 Y 5 Y 5 Y 7 6 Y 5 Y NA Y 7 Y 5 5 5 5 5 5 NA NA NA NA NA
4.4.4.1 AG‐04
Only 2 samples, both of heavily contaminated soils, were collected from the AG‐04 site. Both were heavily contaminated by petroleum, with concentrations of total PAC of 2,900 and 3,300 mg/Kg. The associated TEM concentrations of 590,000 – 690,000 mg/Kg imply samples consisting of more oil than inorganics (i.e. 59% ‐ 69% oil). The biomarker fingerprints corroborate the petroleum source. 4.4.4.2 AG‐06 Concentrations of total PAC in the 9 soil samples analyzed from AG‐06 ranged from near background concentrations (3 samples ranging from 0.15 to 0.35 mg/Kg total PAC) to heavily contaminated by petroleum. The highest total PAC concentration at AG‐06 was 130 mg/Kg, with 5 other samples ranging from 7.8 – 75 mg/Kg. All of these samples had biomarker fingerprints indicative of oil, and the 5 most contaminated samples had weathering states of 5. Five samples of stream sediments were collected and analyzed for PAC, and had concentrations of total PAC ranging from 0.33 – 2.1 ug/L. The PAC distribution
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indicates a petroleum source, confirmed by the biomarker fingerprint in 4 of the samples. The weathering states of these samples ranged from 5 – 7, again consistent with the pattern of more advanced weathering in oil‐contaminated stream sediments than in soils. Six groundwater samples had concentrations of total PAC as high as 210 ug/L. Another sample contained 26 ug/L, and three more samples contained from 3.2 – 7.2 ug/L The lowest concentration found was 0.60 ug/L. All of these concentrations are clearly above the natural background, and the PAC distribution indicates a petroleum source. The weathering states of the oil in these samples were all 5. Finally, 5 surface water samples were collected and analyzed for PAC. Concentrations of total PAC ranged from 0.078 – 0.11 ug/L, with abundance distributions reflecting mainly the natural background distribution of PAC depicted in Fig. 3. 4.5. Response to Hinchee Memorial of May 2014 In his May 2014 Reply Memorial, Hinchee raised objections to three of the points I made in my December 2013 Rejoinder Report.32 The first objection is with regard to the appropriateness of the Toxicity Characteristic Leaching Procedure (TCLP) for use in conjunction with the RAP remediation. The second is with regard to my criticism of Hinchee’s and Connor’s method to determine the extent of oil weathering. The third is with regard to my characterization of oil weathering and evidence for the rate of weathering of oil‐contaminated soils and sediments in the former Concession Area. I find all three of Dr. Hinchee’s objections without merit, and I stand by the positions I stated in earlier reports. My responses to Dr. Hinchee’s objections follow, in the order presented above. 4.5.1 Appropriateness of the Toxicity Characteristic Leaching Procedure In my December 2013 Rejoinder Report33 I noted that it is in principle not possible for any combination of oil components to reach the regulatory threshold concentration of 1000 mg/L (or even 200 mg/L) through dissolution alone. Consequently, I concluded that to reach this threshold, soils or sediments would have to be saturated with oil, allowing the oil to drain out of soils or sediments as a separate organic phase. In his objection, Dr. Hinchee asserts that this was actually the intention of the test34, that is, to determine whether the oil was sufficiently mobile in soils or sediments to move as a separate phase under application of pressure. But this assertion is belied 32 Short 2013 Rejoinder Report 33 Ibid., p. 23 34 Hinchee May 2014 Response Report, p. 6
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by the instructions given by the EPA for this test,35 which state that when multiphasic samples (i.e. samples that consist of an oil phase and a solid inorganic phase such as oiled soil or sediment samples) are involved, the liquid phase must first be separated from the solid phase, prior to addition of the acidified aqueous phase and subsequent mixing, followed by a second filtration step to separate the added water from the solids. This is not how the tests were actually conducted for the RAP.36 Instead, the acidified water was added immediately before evaluating whether oil could flow out of the soil or sediment sample. The addition of acidified water at the start of the procedure impaired the ability of the oil to flow through the filtration device, an issue noted in our initial February 2013 report.37 4.5.2 Consequences of the Flawed Oil Weathering Method used by Drs. Hinchee and Connor Dr. Hinchee claims that the most important consequence of the flaws I pointed out in the O’Reilly and Thorsen method38 for determining the extent of oil weathering is the effect it has on the solubility of oil components.39 I have never disputed that oil composition changes resulting from differential losses of some components during weathering do affect the effective solubility of the components remaining in the oil. But I do not believe that is the most important consequence of the flawed O’Reilly and Thorsen method for determining oil weathering. Both Dr. Hinchee and Mr. Connor relied on the flawed O’Reilly and Thorsen method to support their claim that the overwhelming majority of oil remaining in contaminated soils and sediments is so weathered that it has become an immobile hardened solid. By showing how this claim is seriously flawed, I raise the likelihood that contaminating oils that remain in the region’s soils and sediments could flow through them. If some of the remaining oil is still sufficiently fluid to be carried by water through flow channels in subsurface clays, a mechanism for transporting free‐ phase weathered crude oil from inside to outside un‐lined pits becomes plausible. Louis Berger has observed sites where this transportation mechanism seems likely and my analysis shows that it is not precluded as Dr. Hinchee and Mr. Connor believe. This is a much more serious consequence of the mistaken inferences based on the flawed O’Reilly and Thorsen method. 4.5.3 Characterization of Weathering Rates for Crude Oil Remaining in Concession Area Soils and Sediments 35 USEPA Method 1311, July 1992, p. 11 36 Louis Berger, 2013, p. 52 37 Ibid., p. 54 38 O’Reilly, K. and Thorsen, W., 2010, Impact of Crude Oil Weathering on the Calculated Effective Solubility of Aromatic Compounds: Evaluation of Soils from Ecuadorean Oil Fields, Soil and Sediment Contamination, 19:391 – 404 39 Hinchee May 2014 Response Report, p. 10
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Dr. Hinchee claims that the method I relied on for determining the weathering state of oil in the former Concession Area is qualitative and questionable, and in any case my application of this method to samples collected in 2013 by Louis Berger in comparison with samples collected earlier and summarized by Chevron expert Dr. Douglas do not support my conclusion regarding weathering rates, inaccurately portrayed by Dr. Hinchee as “arrested biodegradation”. I reject these claims on the basis of the following three observations: 1. Dr. Hinchee states that I claimed that “...hydrocarbons in the former Concession area are in a state of arrested biodegradation...”40. What I actually said was that hydrocarbons are in a state of largely arrested biodegradation41 – a crucially important difference. Under conditions of low oxygen and high oil concentration in soils or sediments, biodegradation rates may be orders of magnitude slower than when oil is spread out as thin layers or small droplets at the soil surface. A state of largely arrested biodegradation does not mean that biodegradation has stopped, but instead that it is so slow that oil may persist, largely unchanged, for decades or longer. 2. The method I relied on to determine oil weathering states is presented in Kaplan and Galperin,42 which is exactly the same method used by Chevron expert Dr. Gregory Douglas to characterize the weathering states of hundreds of oiled soil and sediment samples.43 I used this method in part to avoid the sort of objection raised here by Dr. Hinchee, reasoning that adopting the method used by Chevron’s experts would be viewed as reasonable. In any case I view the qualitative basis of the method as a strength rather than a weakness, because it recognizes the regular sequence of composition changes as oil products weather in the environment, and hence is not vulnerable to quantitative disputes that arise when different analytical methods are applied. For example, complete loss of all the normal alkanes from crude oil by weathering is unmistakable, regardless of the subtle differences in the gas chromatographic or other methods used to measure them. 3. Finally, Dr. Hinchee asserts that comparison of results for determining weathering rates should (ideally) be from the same locations and depths44, but then proceeds to ignore his own advice to arrive at unjustified conclusions regarding weathering rates. Samples collected from the same locations and depths at the beginning and again at the end of a time interval of sufficient duration for reliable detection of weathering are not available. In their absence, weathering changes might be inferred from averaged weathering states of a representative set of 40 Hinchee May 2014 Response Report, p. 12 41 Louis Berger, 2013, p. 61 42 Kaplan and Galperin , 1996 43 Summary of Forensic Analyses of Crude Oil Weathering from 45 Judicial Inspections, August 2004 – November 2006, Chevron, Oriente Region, Ecuador. GSI Environmental, Inc., 2211 Norfolk, Suite 1000, Texas 77098‐4054, May 17, 2007 44 Hinchee May 2014 Response Report, p. 12
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samples. Unfortunately, neither the samples collected for the Judicial Inspections by Chevron in the mid‐2000’s, nor the samples collected by Louis Berger in 2013, can be taken as representative in this sense of the environment sampled, because neither sampling program included a random selection component to the sampling selection process. When Chevron claims their sampling was “representative”45, they are using the term loosely as a synonym for “typical” or “indicative” of results that may be expected at or very near the precise location sampled, and not in the strict scientific sense of the term “representative”. Scientifically, “representative sampling” indicates the sampling locations were selected in a manner such that every possible sampling location within the area represented has an equal chance of actually being sampled. Sampling in this “equal‐probability” manner is the only way to guarantee that the results of the sampling truly represent the entire area sampled. Neither sampling in “typical” areas, nor even “haphazard” sampling, can be taken as truly “representative” in this sense. The sampling conducted by Louis Berger in 2013 and in 2014 was also not truly “representative” in the strict scientific sense of this term, nor has it made out to be so. Instead, the Louis Berger sampling was conducted to evaluate other specific questions such as the plausibility of petroleum migration pathways from the inside to the outside of oiled pits and beyond. Such targeted sampling, tailored for specific purposes that are explicitly stated in advance, is perfectly legitimate, as was acknowledged by Chevron expert Dr. Robert Hinchee46. But this kind of targeted sampling still cannot be taken as “representative” of the broad area where sampling occurred, and especially not for quantitative comparisons on which computations of petroleum weathering rates are based. For example, sampling results indicate that residual petroleum in stream sediments is generally more weathered than petroleum buried in soils. Hence, if sampling one year includes a substantially smaller proportion of stream sediments in comparison to a succeeding year, then the change in the average weathering between these two years may simply reflect the differences in the proportions of sediment and soil samples between the two years, instead of actual differences in weathering. When Dr. Hinchee compares results from Chevron’s Judicial Inspections (JI) during the mid‐2000’s with the 2013 Louis Berger samples to conclude that the average Kaplan & Galperin weathering index increased from 4.6 in to 6.1, he presumes implicitly that both sampling programs were truly representative in the strict scientific sense, and he simply ignores a host of plausible alternative explanations for these results. These alternative explanations are plausible because the sampling 45 Expert Opinion of John A. Connor, P.E., P.G., B.C.E.E. Regarding Remediation Activities and Environmental Conditions in the Former Petroecuador – Texaco Concession, Oriente Region, Ecuador, Response to LBG Report of February 2013, Issued 3 June 2013, p. 12 46 Hinchee May 2014 Response Report, p. 12
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was in fact not truly representative, and so the results compared may reflect primarily differences in the proportions of stream sediments, of surface oil samples (which also tend to be more weathered than buried oil) and of oil buried in soils between the sample sets collected for the mid‐2000’s JI sampling and the 2013 Louis Berger sampling, rather than the actual progress of oil weathering during the intervening time interval. Consequently, Dr. Hinchee’s comparison of average weathering states from the two sampling programs to make inferences with regard to the statistical significance of their differences rests on the clearly unjustifiable assumption that these samples are representative, in flagrant disregard for fundamental principles of scientific inference. In my December 2013 Rejoinder Report47 I noted that the ranges of weathering states from Chevron’s and Louis Berger’s sampling programs broadly overlap, suggesting that little weathering had occurred during the nearly 10 years between them. This in itself is a remarkable testament to the slow rate of weathering. But I did not infer more broadly because any such inferences are limited by the way that sampling was conducted for both the Chevron and the Louis Berger sampling campaigns. 4.6. Comparison of Ecuador Oriente Crude Oil with Bunker Oil Spilled from the Prestige Oil Spill Considerable research has been done on the toxicological effects of other oil spills, especially the Prestige oil spill off the Spanish coast in 2002. To compare this research with conditions in the Oriente requires establishing that the oils involved share at least a broadly similar suite of toxic compounds. The product released in the Prestige oil spill was number 6 fuel oil, also known as Bunker oil, a heavy oil consisting mainly of residual hydrocarbons, resins and asphaltenes that remain after distillation of lighter components during the petroleum refining process. Although removal of these lighter components alters the concentrations of the compounds that remain in the number 6 fuel oil, the abundance distribution of PAHs, usually considered the most persistent class of toxic compounds in petroleum, is broadly similar to that of the original petroleum. The distribution of PACs in the number 6 fuel oil released from the Prestige is presented in Figure 4, along with the comparable distribution in Shushufindi crude oil. Note that both contain the same types of PACs in generally similar proportions, although concentrations of some of the PACs in the Prestige oil are substantially greater than their counterparts in Shushufindi crude oil. However, as Shushufindi crude oil weathers these concentrations will tend to converge, because losses of the lighter petroleum components during weathering mimics to an extent the distillation process in a refinery. The result is that after even modest weathering the toxicity of the Shushufindi crude oil caused by PACs would be broadly comparable with that of the Prestige oil. 47 Short 2013 Rejoinder Report
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Figure 4. Concentrations of polycyclic aromatic compounds in No. 6 fuel oil released by the T/V Prestige (blue bars)48 and in un‐weathered Shushufindi crude oil49 (red bars). BF=benzofluoranthenes; see Fig. 3 legend for other abbreviations.
48 Alzaga A., Montuori P, Ortiz L, Bayona JM, Albaigés J (2004) Fast solid‐phase extraction‐gas chromatography‐mass spectrometry procedure for oil fingerprinting Application to the Prestige oil spill. Journal of Chromatography A 1025:133‐138 49 GSD305171
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