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Original Articles

Incidence of Childhood Leukemia and Oil Exploitation in the Amazon Basin of Ecuador ANNA-KARIN HURTIG, DRPH, MIGUEL SAN SEBASTIÁN, PHD

To determine whether there was any difference in childhood leukemia incidence rates between populations living in the proximity to oil fields and those living in areas free from oil exploitation in the Amazon basin of Ecuador, 91 cancer cases among children (0–14 years) from the provinces of Sucumbios, Orellana, Napo, and Pastaza during the period 1985–2000 were studied. The relative risks for all leukemias indicated significantly elevated levels in the youngest age group (0–4 years), both genders combined (RR 3.48, 95% CI 1.25–9.67), and in all age groups (0–14 years) combined for females (RR 2.60, 95% CI 1.11–6.08) and both genders combined (RR 2.56, 95% CI 1.35–4.86). There was no significant difference between the two groups in all other cancer sites combined. Study results are compatible with a relationship between childhood leukemia incidence and living in the proximity of oil fields in the Ecuadorian Amazon. Key words: crude oil; leukemia; Amazon; Ecuador. I N T J O C C U P E N V I R O N H E A LT H 2 0 0 4 ; 1 0 : 2 4 5 – 2 5 0

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he Amazon basin of Ecuador, known as the “Oriente,” consists of more than 100,000 km2 of tropical rainforest lying at the headwaters of the Amazon river network. The region contains one of the most diverse collections of plant and animal life in the world.1 In 1967, a Texaco–Gulf consortium discovered a rich field of oil beneath the rainforest, leading to an oil boom that has permanently reshaped the region. Since then, foreign companies together with Ecuador’s national oil company have extracted more than two billion barrels of crude oil from the Ecuadorian Amazon. During this process, millions of gallons of untreated Received from the Instituto de Epidemiología y Salud Comunitaria “Manuel Amunárriz,” Apdo. 17-10-7410, Quito, Ecuador. Supported by a grant from Medicus Mundi Gipuzkoa and CapuchinosNavarra. Address correspondence and reprint requests to: Dr. Anna-Karin Hurtig, Geografigränd 14 C, 907 32 Umeå, Sweden; e-mail: .

toxic wastes, gas, and oil have been released into the environment.2 Indigenous federations, peasants’ movements, and environmental groups in Ecuador have organized in opposition to unregulated oil development, charging that contamination has caused widespread damage both to people and to the environment.3–5 Oil development activities include several contaminating processes. In the Amazon basin of Ecuador, each exploratory well that is drilled produces an average of 4,000 cubic meters of drilling wastes (drilling muds, petroleum, natural gas, and formation water) from deep below the earth’s surface. These wastes are frequently deposited into open, unlined pits called separation ponds, from which they either are directly discharged into the environment or leach out as the pits degrade or overflow from rainwater.2,3 If commercial quantities of oil are detected, the production stage starts. During production, oil is extracted in a mixture with formation water and gas and separated in a central facility. At each facility, over 4.3 million gallons of liquid wastes are generated every day and discharged without treatment into pits. Roughly 53 million cubic feet of “waste” gas from the separation process are burned daily without temperature or emissions controls. Additional potential contamination of the air is generated at pits and oil spills by hydrocarbons coming from standing oil slicks.6 Routine maintenance activities at over 300 producing wells discharge an estimated 5 million gallons of untreated toxic wastes into the environment every year. Leaks from wells and spills from tanks have been common.7 According to a study conducted by the government in 1989, spills from flow lines alone were dumping an estimated 20,000 gallons of oil every two weeks.8 Spills from the main and secondary pipelines are also common. In 1992, the Ecuadorian government recorded approximately 30 major spills, with an estimated loss of 16.8 million gallons of crude oil.3 Currently, it has been estimated two big spills occur per week from the main oil fields in the region.9 For instance, in 1989 at least 294,000 gallons and in 1992,

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Figure 1—Map showing counties included in the study; exposed counties in grey.

Although several studies have focused on residents exposed to major oil spillages,15–17 epidemiologic studies of communities exposed to oil pollutants near oil fields are few.18,19 In a study in the Amazon basin of Ecuador, an excess of cancers was observed among males in a village located in an oil-producing area.20 A later study from the Amazon basin of Ecuador found significantly higher incidences of all cancer sites combined in both men and women in counties where oil exploitation had been on going for at least 20 years. Significantly elevated levels were observed for cancers of stomach, rectum, skin (melanoma), soft tissue, and kidney in men and for cancers of the cervix and lymph nodes in women. An increase in hematopoietic cancers was also observed in children.21 The object of the present study was to examine in detail of the incidence of leukemia in the age group 0–14 years to determine whether there was any difference in incidence rates between populations living in proximity to oil fields and those living in areas free from oil exploitation in the Amazon basin of Ecuador.

POPULATION AND METHODS Area of Study

about 275,000 gallons of crude oil caused the Napo river (1 km wide) to run black during one week.10 Overall, more than 30 billion gallons of toxic wastes and crude oil had been discharged into the land and waterways of the “Oriente” by 1993.3 This compares to the 10.8 million gallons spilled in the Exxon Valdez disaster in Alaska in 1989, one of the most damaging sea oil spills that has ever occurred. In 1994, the Ecuadorian environmental and human rights organisation Centro de Derechos Económicos y Sociales [Center for Economic and Social Rights] released a report documenting dangerous levels of toxic contamination.11 Concentrations of polynuclear aromatic hydrocarbons found in drinking, bathing, and fishing waters were 10 to 10,000 times greater than allowable under the United States Environmental Protection Agency guidelines. In 1999, the Instituto de Epidemiología y Salud Comunitaria “Manuel Amunárriz” (IESCMA), a local health nongovernmental organization, undertook water analysis for total petroleum hydrocarbons (TPH) in communities in the proximity of oil fields and communities far distant from them. Water analyses showed high levels of exposure to oil-derived chemicals among the residents of the exposed communities.12 In some streams hydrocarbon concentrations reached 144 and 288 times the limit permitted by the European Community regulation.13 The same year, a report from the Ministry of Environment supported these results, when concentrations of TPH over 300 times the limit permitted were found in the streams of one of the communities of the previous study.14

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The study was carried out in the provinces of Sucumbios, Orellana, Napo, and Pastaza, situated in the eastern part of Ecuador (Figure 1). Each province is divided into counties (cantones). The study area has a total population of approximately 356,406 indigenous people and peasants.22 The indigenous people live in small communities scattered along the rivers, making their living by hunting, fishing, and subsistence agriculture. The peasants arrived to the area in the 1970s, following the paths opened by oil companies. They make their living mainly by agriculture and cattleraising. In oil-producing areas approximately 2% of the working population is employed by the oil industry.23 Physical infrastructure in the region is poor. Few villages and small towns (10,000–15,000 citizens) have electricity and piped drinking water, the majority of the inhabitants live without these facilities. Many of the roads in oil-producing counties are paved by crude oil to reduce the amount of dust otherwise produced in this tropical climate. In each province there is a provincial hospital and the counties have health centers. The hospitals have no histopathology services and no access to radiotherapy or chemotherapy. Two mission hospitals with well functioning infrastructures are located in the no–oil-producing counties of Mera and Archidona. Oil-producing areas have no better medical facilities than those areas where no such industry is present. Qualified personnel in the oil industry are contracted from the capital or abroad and flown out in case of health problems. Only recently have some oil companies included health expenditures in their contracts

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TABLE 1. Risks of Leukemia and All Other Cancers for Exposed versus Non-exposed to Oil Pollution by Age Group and Sex, Amazon Region, 1985–2000 All Leukemias _____________________________________ Cases in Exposed Group RR (95 % CI)

All Other Cancers ______________________________________ Cases in Exposed Group RR (95 % CI)

0–4 years old Female Male Both

6 8 14

7.58 (0.91–62.99) 2.45 (0.74– 8.13) 3.48 (1.25– 9.67)

6 8 14

1.52 (0.46– 4.97) 1.96 (0.64– 5.98) 1.74 (0.77– 3.92)

5–9 years old Female Male Both

4 3 7

1.72 (0.38– 7.68) 3.78 (0.39–36.37) 2.23 (0.65– 7.62)

3 3 6

0.77 (0.18– 3.24) 3.78 (0.39–36.37) 1.28 (0.41– 3.95)

10–14 years old Female Male Both

6 1 7

2.05 (0.58– 7.26) 1.31 (0.08–20.94) 1.87 (0.59– 5.89)

4 3 7

1.82 (0.41– 6.96) 1.31 (0.26– 6.49) 1.56 (0.34– 4.64)

0–14 years old Female Male Both

16 12 28

2.60 (1.11– 6.08) 2.52 (0.95– 6.72) 2.56 (1.35– 4.86)

13 14 27

1.30 (0.60– 2.81) 1.96 (0.85– 4.53) 1.57 (0.90– 2.76)

with residents. Two counties, Sachas and Shushufindi, are producing and processing palm oil. The oil industry is the only major industry in the region.

Cancer Data No cancer registry is available in the Amazon region. Suspected cancer cases are referred from these provinces to Quito, the capital. All cases diagnosed in Quito are registered in the National Cancer Registry.24 This register was used for the purpose of our study. During 1985–2000, 1,207 cases of cancer were reported to the National Cancer Registry from the provinces of Sucumbios, Orellana, Napo, and Pastaza among all ages. The National Cancer Registry contains personal identification, gender, age at diagnosis, cancer site, histology (the 10th International Classification of Diseases), year of diagnosis, residence at diagnosis (county), and education. In the register, eight cases lacked data on age and three cases among the age group 0–14 years lacked data on place of residence; those were excluded from the study.

Population Data Population data from the counties of the four provinces by gender and five-year age strata for the year 1993 were used. These were the projections of the National Institute of Statistics and Census based on the 1990 National Census.25

Exposure Status The study was ecologic, and exposure status was defined on a county level. Exposed children were defined as those living in a county where oil exploita-

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tion had been ongoing for at least 20 years at the time of the study. Non-exposed were identified as those counties without oil development activities (excluding seismic studies during the late 1990s with no exploitation activities). Four counties (Lago Agrio, Shushufindi, Orellana, and Sachas; 56,202 children; 51.5% males) were defined as exposed and 11 (Cascales, Pto. El Carmen, La Bonita, Lumbaqui, Aguarico, Tena, Archidona, El Chaco, Baeza, Puyo, Mera; 71,970 children; 50.7% males) as non-exposed.

Statistical Analysis Incidence rates for overall and specific cancer sites were calculated. Relative risks (RRs) along with the 95% confidence intervals (CIs) were calculated for males and females.

RESULTS Between 1985 and 2000 a total of 91 cases of cancers, including 42 leukemia cases, were observed in the study area among children 0–14 years old. Twenty-eight cases of leukemia and 27 cases of other cancers occurred in exposed counties. Data on all leukemia and all other cancer sites combined by gender and age group are presented in Table 1. The RR for all leukemia indicated significantly elevated levels in the youngest age group (0–4 years), both genders combined (RR 3.48, 95% CI 1.25-9.67), and in all age groups (0-14 years) combined for females (RR 2.60, 95% CI 1.11–6.08) and both genders combined (RR 2.56, 95% CI 1.35–4.86) in the exposed counties. There was no significant difference in relation to exposure status in all other cancer sites combined.

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TABLE 2. Risks of Acute Leukemia cell type for category of exposed versus non-exposed by sex, Amazon region, 1985-2000 Cases in Exposed Group

Incidence Rate

RR (95 % CI)

14 6 20

3.21 1.30 2.22

2.60 (1.05- 6.45) 2.52 (0.63-10.09) 2.56 (1.20- 5.47)

Myeloblastic leukemia Female Male Both

2 6 8

0.46 1.30 0.89

2.60 (0.24-28.69) 2.52 (0.63-10.09) 2.56 (0.77 -8.50)

All leukemia cell types Female Male Both

16 12 28

3.67 2.60 3.11

2.60 (1.11- 6.08) 2.52 (0.95- 6.72) 2.56 (1.35- 4.86)

Lymphoblastic leukemia Female Male Both

Data on the distribution of leukemia cell types by group and gender are presented in Table 2. Acute lymphoblastic leukemia (ALL) accounted for 20 (71.0%) of the leukemia cases in the exposed group and 10 (71.0%) of those in the unexposed group. ALL was found to be significantly elevated in the exposed counties for females (RR 2.60, 95% CI 1.05–6.46) and for both genders combined (RR 2.56, 95% CI 1.35–4.86).

DISCUSSION This study compared incidences of childhood leukemia in counties with oil-development activities and those without in the Amazon basin of Ecuador (1985–2000). The results showed considerable differences in the incidences of childhood leukemia according to our exposure definition. Childhood leukemia is the most common cancer among children. In Ecuador, 60% of deaths due to cancer in children less than 14 years of age are attributable to leukemia. The standardized incidence of leukemia for the Quito population has not changed in the 15 years of the NCR (5–6/100.000), being similar for both sexes.24 While low incidences could be expected in our rural population compared with Quito, the possibility of underreporting must be considered. The reasons for a higher incidence among girls are unclear. A possible explanation might be more exposure to contaminated water during daily activities. Crude oil is a complex mixture of many chemical compounds, mostly hydrocarbons. The petroleum hydrocarbons of most toxicologic interest are volatile organic compounds (benzene, xylene, and toluene) and polynuclear aromatic hydrocarbons (PAH).26 Benzene is a well-known cause of leukemia,27,28 and perhaps other hematologic neoplasms and disorders.29,30 No adequate data on the incidences of cancers after human exposures to the other volatile organic chemicals exist.15 An ecologic study that examined the relationship between the incidence of leukemia and volatile

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organic chemical (VOC) contamination of drinking water supplies in the United States suggested that drinking water contaminated with VOCs might increase the incidence of leukemia among exposed females.31 Corresponding studies of the incidence of leukemia in people residing near oil fields are lacking. More problematic, related existing studies tend to be based on lower levels of exposure than those in Ecuador. A study from Wales did not find an association between the incidence of leukemias and lymphomas in children and young people and their residence in the area around the BP Chemical site at Baglan Bay, South Wales.32 A report encompassing all industrial complexes that include major oil refineries in Great Britain found no evidence of an association between residence near oil refineries and leukemia or non-Hodgkin’s lymphoma.33 However, the relationships between leukemia and toxic exposures were examined in a case–control study of a cluster of 14 childhood cases in a restricted area in The Netherlands. Results showed excessive exposures both to insecticides and to petroleum products among the cases.34 There are also several studies showing that petroleum and fuel exhaust exposures are leukemia hazards in industrial workers, and that not all of the toxicity is explained by benzene. Childhood leukemia and other childhood cancers have been geographically associated with industrial atmospheric effluent, for example, with petroleum-derived volatiles in Great Britain.35,36 Few studies have been conducted in petroleum-exploration and petroleum-production workers. High incidences of leukemia in oil-fields workers have been found in studies carried out in the United States and China.37,38 Because they reflect group rather that individual characteristics and exposures, ecologic studies must be interpreted cautiously. The use of aggregated data instead of the joint distributions of exposure, outcome, and covariates at the individual level may lead to severe bias in ecologic analyses.39 Using narrow exposure data and small units of analysis (parishes) could have minimized the

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effect of this bias, but was not feasible in the present study due to the lack of data. Overall, it is difficult to measure the impact of the ecologic bias in the study. Because pf geographic and socioeconomic impediments to accessing adequate health care, it is likely that many cases of cancer never got referred to Quito from the study area. Health services are poor in both exposed and non-exposed counties, but factors such as diagnostic skills and transport facilities might influence referral patterns. It is also possible that on a county level there are differences in racial composition and life-style patterns between populations that might confound risk estimates. However, no information about the distribution of such potentially important confounders was available. Several limitations in the data and methods need also to be considered. Population data relied on county census figures estimated from the 1990 National Census. Errors in population estimates, including differential migration patterns, might bias estimates of risk. It is possible that the exposed counties had had more rapidly increasing populations compared with the non-exposed ones, providing a relatively greater underestimate of population denominators for these counties. Data from the National Institute of Statistics and Census give no evidence that this is the case.22,25 Cancer rates were based on county of residence at time of diagnosis without information as to length of time at current residence. Because the latency period for cancer can be long, an assessment of migration into and out of counties as well as residence time in the county would have been useful, but no data were available. One possibility to explain any excess risk near an industrial source is that it reflects parents’ occupational exposures rather than environmental factors. Parents’ occupational data were not available. Two exposed counties have also oil palm industry, where pesticide use is common. The impact of this exposure on the results presented could not be measured. The results suggest a relationship between leukemia incidence in children and living in the proximity of oil fields, although this ecologic study cannot lead to a causal inference. However, the possibility of a causal relationship is supported by several criteria. First, the strength of the association between the outcome and the exposure; second, the finding that only leukemia was at increased risk in the exposed area increases the plausibility of the results. Third, by using surrogate data that are representative of several decades of oil pollution exposure, a plausible time sequence from exposure to development of disease can be inferred. Further research is necessary to determine whether the observed associations do reflect an underlying causal relationship. A next step could be epidemiologic studies at the individual level. Meanwhile, an environmental monitoring system to assess, control, and assist in the elimination of sources of pollution in the area

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and a surveillance system to gain knowledge of the evolution of cancer incidence and distribution in the area are urgently recommended. The authors thank Dr. Yepez from the National Cancer Registry for providing the data.

References 1. Ecuador rainforest. (accessed 25 April 2003). 2. Kimerling J. Amazon Crude. New York: Brickfront Graphics, 1991. 3. Jochnick C, Normand R, Zaidi S. Rights violations in the Ecuadorian Amazon: the human consequences of oil development. Health Human Rights. 1994;1:82-100. 4. Garzón P. Impacto socioambiental de la actividad petrolera: estudio de caso de las comunidades San Carlos y La Primavera. In: Varea A, Ortiz P (eds). Marea negra en la Amazonía: conflictos socioambientales vinculados a la actividad petrolera en el Ecuador. Quito, Ecuador: Abya-Yala, 1995: 265-94. [In Spanish] 5. Kimerling J. Oil development in Ecuador and Peru: law, politics and the environment. Draft paper presented at Amazonia 2000: Development, Environment and Geopolitics. London, England: Institute of Latin American Studies, University of London, 1998. 6. Centro de Derechos Económicos y Sociales. El petróleo no es eterno. Quito, Ecuador: CDES, 1999. [In Spanish] 7. Almeida A. Reseña sobre la historia ecológica de la Amazonía ecuatoriana. In: Martínez E (ed). Ecuador post petrolero. Quito, Ecuador: Acción ecológica, 2000. [In Spanish] 8. Dirección General de Medio Ambiente. Estudio de impacto ambiental 42. Quito, Ecuador: Dirección General de Medio Ambiente, 1989. [In spanish] 9. Dos derrames de petróleo al mes en el campo Auca (2002) El Comercio, 18 October. [In Spanish] 10. Rainforest Action Network News. (accessed 26 April 2003). 11. Centro de Derechos Económicos y Sociales. Violaciones de derechos en la Amazonía Ecuatoriana. Quito, Ecuador: AbyaYala., 1994. 12. San Sebastián M. Informe Yana Curi: impacto de la actividad petrolera en la salud de poblaciones rurales de la Amazonia ecuatoriana. Quito, Ecuador: Cicame & Abya-Yala, 2000. [In Spanish] 13. Zehner R, Villacreces LA. Estudio de la calidad de aguas de río en la zona de amortiguamiento del Parque Nacional Yasuní. Primera fase: monitoreo de aguas—screening Octubre de 1997. Coca, Ecuador: Laboratorio de Aguas y Suelos P. Miguel Gamboa-Fepp, 1998. [In Spanish] 14. Ministerio de Medio Ambiente. Informe de inspección ambiental al área de las comunidades Flor de Manduro y Centro Manduro ubicadas en el bloque siete operado por la compañía Oryx. Quito, Ecuador: Ministerio de Medio Ambiente, 1999. [In Spanish] 15. Campbell D, Cox D, Crum J, Foster K, Christie P, Brewster D. Initial effects of the grounding of the tanker Braer on health in Shetland. BMJ. 1993;307:1251-5. 16. Palinkas LA, Petterson JS, Russell J, Downs MA. Community patterns of psychiatric disorders after the Exxon Valdez oil spill. Am J Psychiatry. 1993;150:1517-23. 17. Lyons RA, Temple MF, Evans D, Fone DL, Palmer SR. Acute health effects of the Sea Empress oil spill. J Epidemiol Commun Health. 1999;53:306-10. 18. San Sebastián M, Armstrong M, Stephens C. La salud de mujeres que viven cerca de pozos y estaciones de petróleo en la Amazonía ecuatoriana. Rev Panam Salud Pública. 2001;9:37584. [In Spanish] 19. San Sebastián M, Armstrong M, Stephens C. Outcome of pregnancy among women living in the proximity of oil fields in the Amazon basin of Ecuador. Int J Occup Environ Health. 2002; 8:312-9. 20. San Sebastián M, Armstrong M, Cordoba JA, Stephens C. Environmental exposure and cancer incidence near oil fields in the Amazon basin of Ecuador. Occup Environ Med. 2001;58:517-22.

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21. Hurtig AK, San Sebastián M. Geographical differences of cancer incidence in the Amazon basin of Ecuador in relation to residency near oil fields. Int J Epidemiol. 2002;31:1021-7. 22. Instituto Nacional de Estadísticas y Censos del Ecuador. VI Censo de Población y V de Vivienda. Quito, Ecuador: INEC, 2001. [In Spanish] 23. United Nations Childrens Fund. Situación de las madres y los niños en zonas de grandes proyectos. Quito, Ecuador: UNICEF, 1992. [In Spanish] 24. Sociedad de Lucha contra el Cáncer. Cáncer en regiones del Ecuador. Quito, Ecuador: SOLCA, 2001. [In Spanish] 25. Instituto Nacional de Estadísticas y Censos del Ecuador. V Censo de Población y IV de Vivienda. Quito, Ecuador: INEC, 1990. [In Spanish] 26. IARC. Monographs on the evaluation of the carcinogenic risk of chemicals to man: occupational exposures to petroleum refining; crude oil and major petroleum fuels. Volume 45. Lyon, France: International Agency for Research on Cancer, 1989. 27. Wong O. An industry wide mortality study of chemical workers occupationally exposed to benzene. I. General results. Br J Ind Med. 1987;44:365-81. 28. Austin H, Delzell E, Cole P. Benzene and leukemia. A review of the literature and a risk assessment. Am J Epidemiol. 1988; 127:419-39. 29. Hayes RB, Yin SN, Dosemeci M, et al. Benzene and the doserelated incidence of hematologic neoplasms in China. J Natl Cancer Inst. 1997;89:1065-71. 30. Savitz DA, Andrews KW. Review of epidemiologic evidence on benzene and lymphatic and hematopoietic cancers. Am J Ind

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Med. 1997;31:287-95. 31. Fagliano J, Berry M, Bove F, Burke T. Drinking water contamination and the incidence of leukemia: an ecologic study. Am J Public Health. 1990;80:1209-12. 32. Lyons RA, Monaghan SP, Heaven M, Littlepage BN, Vincent TJ, Draper GJ. Incidence of leukaemia and lymphoma in young people in the vicinity of the petrochemical plant at Baglan Bay, South Wales, 1974 to 1991. Occup Environ Med. 1995;52:225-8. 33. Wilkinson P, Thakrar B, Walls P, et al. Lymphohaematopoietic malignancy around all industrial complexes that include major oil refineries in Great Britain. Occup Environ Med. 1999; 56:577-80. 34. Mulder YM, Drijver M, Kreis IA. Case–control study on the association between a cluster of childhood haematopoietic malignancies and local environmental factors in Aalsmeer, The Netherlands. J Epidemiol Communi Health. 1994;48:161-5. 35. Knox EG, Gilman EA. Hazard proximities of childhood cancers in Great Britain from 1953–80. J Epidemiol Commun Health. 1997;51:151-9. 36. Knox EG, Gilman EA. Migration patterns of children with cancer in Britain. J Epidemiol Commun Health. 1998;52:716-26. 37. Sathiakumar N, Delzell E, Cole P, Brill I, Frisch J, Spivey G. A case–control study of leukemia among petroleum workers. J Occup Environ Med. 1995;37:1269-77. 38. Yang C, Zhang X. Incidence survey of leukaemia in China. Chin Med Sci J. 1991;6:65-70. 39. Dos Santos Silva I. Cancer Epidemiology: Principles and Methods. Lyon, France: International Agency for Research on Cancer, 1999.

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Letters Chevron–Texaco’s Science From the Guest Editors:—In their letter, “Elevating the Level of Scientific Discourse,”1 Rothman and Arellano claim that “it would be a misuse of science to use weak or flawed studies as a pretext to support the claim that the reason to preserve the Amazon environment is to avoid an adverse effect on cancer rates.” However, as those authors know, there is no such thing as perfect science. Weak or “flawed” studies can be useful in determining risk. On the other hand, as shown by Gennaro et al.’s article in this issue, the petrochemical companies, including Texaco, manipulated studies to avoid liability and protective public health regulations. Obviously, manipulated studies should not serve as a basis for public health decisions. Such has been the case in the many studies produced by Texaco and Chevron that they claim show that their workers, exposed to many known carcinogens, are healthier than unexposed populations.2–6 This may in part be due to the healthy-worker effect, but the companies have also been known to use dubious methods to study their own workers’ disease, including counting exposed subcontractors as part of “unexposed” control groups.7 These companies often use studies to justify workplace and environmental exposures that are dangerous according to both common sense and scientific evidence. Texaco has tried to use Rothman and Arrellano’s work to discredit studies showing adverse health effects of its practices. Unfortunately, a magnifying glass taken to the Ecuador studies cannot make the risk disappear. This is something that Rothman knows well; he begins his chapter in his jointly edited book with a critical analysis

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of Hill’s seminal work on epistemology,8 pp. 24-–8 yet he does not criticize Hill’s statement that, “All scientific work is incomplete— whether it be observational or experimental. All scientific work is liable to be upset or modified by advancing knowledge. That does not confer upon us a freedom to ignore the knowledge we already have, or to postpone the action that it appears to demand at a given time.”9 p 300 Hill also advises us to consider several “points of view” in considering causal relationships.9 Laboratory findings can confirm or substantiate meager or equivocal results in humans or identify carcinogenic risks to humans without having any other information. In the absence of reliable chemical carcinogenesis data for humans, the prudent public health path to take is to rely on controlled and well-conducted long-term carcinogenesis bioassays using laboratory animals. Animal study findings have led to an international consensus that a number of the agents generated during oil production are toxic and/or carcinogenic, and with foresight may be deemed to have the potential for constituting serious public health hazards. The evidence in this instance is that containment has been deficient and that widespread environmental damage has resulted.10–15 The responsible companies have either failed to conduct or have failed to publish the qualitative and quantitative environmental and biological monitoring that Rothman and Arellano deem valuable. Rothman and Arellano would appear more even-handed had they been as critical of their sponsors’ failures to contain hazards and conduct ade-

quate environmental monitoring as they were of the scientists who interpreted the only data that were available. “Weak and flawed” or not, as a consequence of their sponsor’s conduct these were the only data available to identify the public health impact of the exploitation of these natural resources. Rothman and Arellano should not be shocked to discover that the company that solicited their review and personal appearance at a press conference (entitled “Experts Say Health Studies Promoted by Lawyers and Activists are Flawed, Biased, and Inconclusive”) was using them to influence public opinion, political leaders, and the courts in Ecuador. It remains to be seen whether these antics will help the oil company escape blame for the health and environmental damage in this part of the Amazon. During the more than two decades they operated in Ecuador, Texaco never reinjected wastewater from the drilling process, even though the company held patents on the most effective way to do so.16,17 Wastewater re-injection has been required since 1911 in Texas and by 1971 was described by industry as being “integral” to oil production in the United States.18 Reinjecting the wastewater in the Amazon would have cost Texaco only about $1/barrel, according to conservative estimates.19 During most of the time Texaco was extracting oil from Ecuador, it was sold for US$12–35 per barrel.20 Surely the oil giant could have afforded to take the same precautions in Ecuador as it did in the United States. Despite Rothman and Arellano’s claim, we do not wish to “contend that Chevron–Texaco would not be allowed to request an expert evalu-

ation of scientific work.” Instead, we urge that scientists truly interested in the public and environmental health be aware of the uses to which their work may be put. For Chevron–Texaco science is not a tool for pursuing truth or human happiness. Instead, it is a means to the corporation’s goal of maximizing profit. Profit maximization is not the aim of public health, and public health scientists should not be surprised if they are called to task for serving the interests of corporations with such self-interest. We wish the oil company had spent its resources to implement 90year-old hygiene practices that could have protected the environment and people. If they had done so, perhaps they could have avoided spending so much on hiring an army of lawyers, public relations specialists, scientific consultants, and expert witnesses, etc., to defend their indefensible conduct. DAVID S. EGILMAN, MD, MPH SUSANNA RANKIN BOHME, AM 8 North Main Street, Suite 404 Attleboro, MA 02703 References

2.

3.

4.

5.

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7.

8. 9. 10.

11.

1. Rothman KJ, Arellano F. Elevating the level of scientific discourse (letter). Int

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J Occup Environ Health. 2005;11:3278. Wong O, Morgan RW, Bailey WJ, Swencicki RE, Claxton K, Kheifets L. An epidemiological study of petroleum refinery employees. Br J Ind Med. 1986; 43:6-17. Divine BJ, Hartman CM. Update of a study of crude oil production workers 1946–94.Occup Environ Med. 2000; 57:411-7. Divine BJ, Hartman CM, Wendt JK. Update of the Texaco mortality study 1947–93: Part I. Analysis of overall patterns of mortality among refining, research, and petrochemical workers. Occup Environ Med. 1999;56:167-73. Divine BJ, Wendt JK, Hartman CM. Cancer mortality among workers at a butadiene production facility. IARC Sci Publ. 1993;(127):345-62. Divine BJ, Barron V, Kaplan SD. Texaco mortality study. I. Mortality among refinery, petrochemical, and research workers. J Occup Med. 1985; 27:445-7. Ludwig ER, Madeksho L, Egilman D. Re: Mesothelioma and lung tumors attributable to asbestos among petroleum workers. Am J Ind Med. 2000; 37:275-82. Rothman KJ, Greenland S (eds). Modern Epidemiology, 2nd ed. Philadelphia, PA: Lippincott Raven, 1998. Hill AB.The Environment and disease: association or causation? Proc Royal Soc Med. 1965;58:295-300. San Sebastian M, Armstrong B, Cordoba JA, Stephens C. Exposures and cancer incidence near oil fields in the Amazon basin of Ecuador. Occup Environ Med. 2001;58:517-22. San Sebastian M, Armstrong B, Stephens C. Health of women living near oil wells and oil production stations in the Amazon region of Ecuador. Rev Panam Salud Publica. 2001;9:375-

84. [In Spanish] 12. San Sebastian M, Armstrong B, Stephens C. Outcomes of pregnancy among women living in the proximity of oil fields in the Amazon basin of Ecuador. Int J Occup Environ Health. 2002;8:312-9. 13. Hurtig AK, San Sebastian M. Gynecologic and breast malignancies in the Amazon basin of Ecuador, 1985–1998. Int J Gynecol Obstet. 2002;76:199-201. 14. Hurtig AK, San Sebastian M. Geographical differences in cancer incidence in the Amazon basin of Ecuador in relation to residence near oil fields. Int J Epidemiol. 2002;31:1021-7. 15. Hurtig AK, San Sebastian M. Incidence of childhood leukemia and oil exploitation in the Amazon basin of Ecuador. Int J Occup Environ Health. 2004;10:245-50. 16. United States Patent 3,680,389. Frederick H. Binkely, Jr., et al., assignor to Texaco Inc. August 1, 1972. 17. United States Patent 3,817,859. Jack F. Tate, assignor to Texaco Inc. June 18, 1975. 18. Water Pollution Control Legislation— 1971 (Proposed Amendments to Existing Legislation). Hearings before the Committee on Public Works, House of Representatives, Ninety-Second Congress, First Section. July, September, and November 1971. Washington, DC: Committee on Public Works, p 1713. 19. Lawrence AW, Miller JA. A regional assessment of produced water treatment and disposal practices and research needs: topical report. Prepared by Remediation Technologies for Gas Research Institute, Contract No. 5091-253-2215. August 1995. 20. World Oil Market and Oil Price Chronologies: 1970–2004. March 2005. Energy Information Association. . Accessed 7/14/05.

Letters

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457

“Yana Curi” Report The impact of oil development on the health of the people of the Ecuadorian Amazon

Dr. Miguel San Sebastián Dr. Juan Antonio Córdoba Translation by Kristen Keating

-------------------------------------------------------------------------------------------------Departamento de Pastoral Social del Vicariato de Aguarico London School of Hygiene and Tropical Medicine Medicus Mundi

For all those who fight to defend the land and the people of the Oriente...

“The earth is not dying, she is being killed. And the people who are killing her Have names and addresses.” -U. Utah Philips

Vicariato Apostólico de Aguarico Editions: CICAME Coca, Orellana Authors: Miguel San Sebastián Juan Antonio Córdoba June 1999

CONTENTS INTRODUCTION

1

I. IS THERE REASON FOR CONCERN?

3

1.

The people’s response to the situation

4

2.

Evidence of the dangers of contamination

5

II. THE CASE OF SAN CARLOS

6

1.

Area of study

6

2.

How did we conduct the study?

7

3.

What were the results?

9

4.

What is the significance of these results?

13

5.

Some final recommendations

15

APPENDIX 1

16

APPENDIX 2

23

APPENDIX 3

24

BIBLIOGRAPHY

25

1

INTRODUCTION Oil has been and continues to be not only one of the principal sources of income for Ecuador, but also a destructive force on its environment. Since 1972, international oil companies led by Texaco in collaboration with the national company, Petroecuador (previously CEPE), have extracted almost two billion barrels of oil mainly from the region of the Amazon. In this process, millions of gallons of oil and toxic waste have been dumped directly into the environment. Indian communities and farmers, as well as national environmental groups, have spoken out during the past years in clear opposition to the lack of regulation of oil industry development, complaining that the contamination has caused enormous damage to the environment as well as to the health of the people1. Despite the evident impact of oil exploitation on the Amazon region’s ecosystem, and the potential health risks for the area’s inhabitants, there has been no integral chemical study of its impact on the environment,2 and information about the health effects on residents of these oil-extracting areas is scarce 3. But the residents are extremely worried about the risk that the contamination poses to their health. The oil companies and the government itself have challenged the affected communities and environmental groups to provide evidence of harmful effects on health in order for them to change their oil-extracting strategies and control contamination. As a result, the Departamento de Pastoral Social del Vicariato Apostólico of Aguarico, sensitive to the problem and to the concerns of the communities, has begun, in collaboration with the Department of Tropical Medicine and Hygiene of the University of London, to investigate the possible consequences that the oil contamination has on the health of the rural population of the Ecuadorian Amazon. The two main objectives of this study are: • increase the limited knowledge that exists about the health effects caused by the contamination surrounding the oil wells. • answer the questions and concerns of the people of the Oriente about the effects that this contamination has on their health. This study, called Yana Curia, begins with an initial report on the risk of cancer that residents of the oil exploitation zones are exposed to. In the months to come, a second report will be published with the results of -------------------------------------------------------------------------------------------a

YANA CURI: Quechua for “oil”. Literally “Black Gold.”

2 another, more extensive study on the impact of the oil contamination on the health of the people. The current document is divided into two parts: ð the first part briefly presents the problem of oil contamination in the Ecuadorian Amazon and the response of the people of the region to the situation. ð the second part examines the case of San Carlos, a town subjected to elevated and continuous exposure to oil contaminants, where a grouping of cancers was discovered. In this section, the development of the investigation of this grouping, the significance of the results, and some final recommendations are presented. We would like to especially thank Rosa Moreno for her collaboration and hospitality each time we showed up in San Carlos; the departments of statistics of the Society to Fight Cancer (Sociedad de Lucha Contra el Cancer / SOLCA), the Eugenio Espejo Hospital and the Baca Ortiz Hospital for the data they provided, Janet Andrade and Dr. Pepe Yépez, for their interest and help with the various problems that arose while conducting our study; our friends from the associations for health promotion “Sandi Yura” and the Fundación Salud Amazónica for all of their logistic support. Finally, we are grateful to the Spanish non-governmental organization Medicus Mundi Gipúzkoa, which collaborated in the financing of our study.

-------------------------------------------------------------------------------------------a

YANA CURI: Quechua for “oil”. Literally “Black Gold.”

3

I.

IS THERE CAUSE FOR CONCERN?

Since the start of oil exploitation in the Ecuadorian Oriente, there has been no clear policy for reducing the devastating contamination that it causes. Even the few areas created for the conservation of ecosystems, such as national parks and protected areas, have not been respected by the oil companies4. With the development of the oil industry, roads were constructed to make possible the colonization and deforestation of a million hectares of forest. In addition, every day hundreds of oil wells generate more than 4.3 million gallons of toxic waste, which are almost totally unloaded or spilled into the untreated environment. The crude oil, poured regularly on the roads in order to maintain them and to control dust, is scattered throughout the environment by the rain. It is estimated that the cracks in the in the TransEcuadorian Pipeline (Sistema del Oleoducto Trans-Ecuatoriano [SOTE]) have provoked the spilling of 400,000 barrels of oil. These practices contaminate innumerable rivers, streams, and estuaries, often the only sources of water for the inhabitants of this region. Similarly, every day the continuous burning of oil and millions of cubic feet of gas produce highly toxic compounds that contribute to the contamination of the air. The activities of the oil companies during these years have been characterized by the logic of rapid accumulation with little investment, without taking into account the country’s need for energy or natural resources. Obviously this attitude has led to carelessness and disrespect towards environmental, cultural, and socioeconomic issues of the towns and areas where they operate5. The companies have defended themselves against these accusations, emphasizing the essential importance of oil for the development of Ecuador and claiming that all of their actions have complied with environmental regulations of the country and that their methods followed “the habitual practices of international industry.” They have also sustained that the health problems attributed to this contamination have never been proven6. Despite the fact that the Ecuadorian laws and the very Constitution of the Republic guarantee “the right to live in an environment free of contamination,” with the State responsible for such protection, until now there has been little or no political action by the different governments to

4 follow the law and establish a system of environmental control over the powerful oil industry7.

1.

The people’s response to the situation

From the very beginning, residents of the oil production zones have voiced concerns about the contamination. Farmers and Indians have reported that many local estuaries and rivers, once filled with fish, now lack aquatic life; reports of cattle dying from drinking such water are also frequent. The residents of these zones frequently complain that bathing in these waters causes itchiness and development of rashes on their skin7,8. The Indian communities and farmers of the Oriente have repeatedly complained to the different governments and companies about the situation, demanding better quality of life, attention to their basic needs, technical assistance, and above all, cleaning-up of the contamination. But the response of the governments and the oil companies has consisted of “patches” (covering up some of the pools of waste, constructing a school or latrine here and there, opening a path) without confronting the real root of the problem9,10. However, in 1991 the publication of the book “Amazon Crude”2 by the North American Judith Kimerling elevated oil contamination in Ecuador to the status of an international environmental problem. It was the first time that clear evidence was presented to the media, the government, and the oil companies, that supported the claims of the communities. Kimerling showed how oil development can cause a negative impact on the land and the people in each phase of its cycle, from the first seismic studies and drillings to the phases of production and transport. In 1993, a health promotion association from Sucumbios conducted a study on the effects of oil on health. The study included communities exposed to the contamination and communities where there had been no oil development. The study suggested that the exposed communities had more illnesses, spontaneous abortions, and a higher mortality rate than the communities that were not contaminated3. In this same year, a group of Amazon Indians and farmers representing 30,000 affected individuals took legal action in New York against the oil

5 companies, accusing them of irreparable damage to the environment. After several attempts, the lawsuit has been accepted and in the next few months a United States judge will decide if the trial will take place in the U.S. or in Ecuador10. In 1994, the Center for Economic and Social Rights8 published a report documenting the dangerous levels of oil contamination in the rivers of the northern region of the Ecuadorian Oriente. This same report documents numerous skin problems among the local people apparently related to the oil contamination. Consequently, the Ecuadorian government has been accused of violating human rights. In 1994 the Amazon Defense Front (Frente de Defensa de la Amazonía [FDA]) was created with the participation of numerous organizations of farmers and Indians and local non-governmental organizations (NGOs) with the objective of supervising the trial against Texaco. Since its formation, the group has organized various workshops about the environment, published accusations and reports about oil spills, led community information sessions and organized the visits of government representatives to the contaminated areas, in an intent to open the eyes of the authorities to this disaster.

2.

Evidence of the dangers of contamination

According to published information, the risk of adverse effects on health is greatly increased when one is exposed to the contaminants created by oil extraction. Studies in laboratory animals as well as wild animals show that exposure to oil can cause lesions in various organs, and can provoke birth defects, cancer, and even death. Different studies on the health effects of oil on humans have demonstrated that the exposed populations face an elevated risk of grave and irreversible illnesses, presenting an important public health problem. The effects can present themselves with different intensity in each of the phases of the oil drilling process: exploration, drilling, production, and transport. Appendix 1 presents an extensive review of published information on the impact of oil on the health of animals as well as humans.

6

7

II.

THE CASE OF SAN CARLOS

In October of 1998, the village of San Carlos was visited as a preliminary contact for its inclusion in the study of the impact of oil drilling practices on the health of the people of the Oriente. In the first conversations with the head of nursing at the health center and some residents, the presence of several cases of cancer was observed; they attributed this to elevated and continuous exposure to oil. Through his medical team, the Vicariate of Aguarico decided to carry out an investigation of this potential grouping of cancers.

1.

Area of study

San Carlos is a population located about 12 km. from Joya de los Sachas (heading toward Coca) following a road called vía La Parker. San Carlos belongs to Sachas canton, in the province of Orellana. The town is made up of an urban center (70% of the population) surrounded by a rural zone (Precooperative Abdón Calderón). San Carlos has approximately 1,000 inhabitants. The majority of the population arrived in the 70’s following the routes of access opened by the oil companies. Their livelihood is based on agriculture and raising cattle. The deficient infrastructure of San Carlos does not cover the basic needs of the people. There are no facilities for drinking water and no drainage systems. Only the urban center has electricity, running water, and a health center. The roads are covered with toxic waste. At the entrance to San Carlos is the pumping station Sacha Sur and more than 30 working wells have been identified in the area. Both the station and the wells eliminate their toxic waste in the estuaries and rivers that cross the town. These same water sources are habitually used by the people of the town for drinking, cooking, bathing, and washing clothing. In Sacha Sur there are four powerful torches that burn gas constantly throughout the day and night. Almost all of the oil wells in San Carlos have been functioning for 20 years11.

8

2.

How did we conduct the study?

The investigation of this group of cancers was divided into three parts: • The discovery and confirmation of cases which occurred during the last ten years, 1989-1998; • The calculation of the standard cancer rate in the area of study; this calculation permits us to detect if there is an excess incidence of cancer beyond the expected rate. • The investigation of possible contamination of water in the area. 2.1

Discovery and confirmation of cases

The first step in this study was to determine how many cases of cancer had occurred in San Carlos, where they had occurred, and when. Thanks to the collaboration of the head of the local infirmary, a list was created with the names, ages, time of residence and place of diagnosis of all possible cases of cancer in the past ten years, those who had died as well as those who had survived. Then the registers of the hospitals where the patients had been cared for were consulted in order to confirm the diagnosis of cancer. From an initial list of 18 names, after confirming the definitive diagnosis, we were left with ten cases of cancer (there is one more probable case, but the diagnosis has not yet been confirmed). The hospitals were: SOLCA (6 patients), Eugenio Espejo Hospital(3), and Baca Ortiz hospital (1). For each patient, these institutions provided the age, place of residence, date of diagnosis, and type of cancer. 2.2

Calculation of the standard cancer rate.

Once the diagnoses were confirmed, the objective was to determine if the number of cancers found represented a normal occurrence or a true excess. To find out, the standard cancer rate (SCR) was calculated.

9 In order to calculate the SCR, it is necessary to know not only the number of cancers in San Carlos, but also the following information: ð The population of San Carlos; since there had not been an official census of the population of San Carlos for the period 1989-1998, an estimate of the census was used based on the distribution of the population of La Joya de los Sachas canton12 and on data collected in San Carlos as part of the present study. (See Appendix 3). In order to simplify the calculation, the annual census of San Carlos during the period 1989-1998 was assumed to be constant. As we stated earlier, the total population of San Carlos for 1998 was estimated at 1,000 inhabitants (Table 1). ð The rate of cancers in a reference population; in this case we decided that our reference population would be Quito, a city with adequate information on cancer through the National Tumor Registry (Registro Nacional de Tumores RNT). The RNT provides information on the incidence of cancer in the population of Quito, divided by age and sex, for the period 1985-199613. ð Finally, the SCR is calculated by dividing the number of observed cancers (O) in San Carlos during this 10-year period by the number of expected cancers (E) according to the rates of the reference population, in this case Quito (O/E). The calculation of the SCR is explained in Appendix 2. Table 1. Estimated age distribution of the population of San Carlos, 1998. Age 0-4 5-14 15-44 45-64 >65 TOTAL 2.3

Men 94 165 233 46 12 550

Evaluation of the environment

Women 77 135 191 38 9 450

Total 171 300 424 84 21 1000

10 In order to evaluate the extent to which the people of San Carlos were exposed to contamination, samples of water were collected from the areas used by the community to supply drinking water, and water for cooking, bathing, and washing clothes. The analysis of the samples included total hydrocarbons (HT) and was conducted in the water and soil laboratory of the P. Miguel Gamboa School, in Coca. The method for measuring the HT required extraction with 1.1.2-trichlorotrifloro-ethane and determination by infra-red spectophotometry. The exact origin of the water samples was hidden from the laboratory investigators in order to avoid subjectivity in the interpretation of the results. Because of the lack of economic and technical resources, an evaluation of the soil and the air in these zones was not possible.

3.

What were the results?

3.1

Discovery and confirmation of cases.

Ten patients with cancer were found in San Carlos during the period from 1989-1998. Of these 10 cases, 3 suffered from stomach cancer; this number represents almost 40% of the cancers which we consider those only found in males. The rest of the cancers were of the larynx (1), liver (1), a melanoma (a type of skin cancer), bile duct (1), cervix (1), a lymphoma (a cancer of the lymphatic ganglions) and leukemia (a cancer of the white blood cells). Almost all of the cases of cancer found where diagnosed in males (80%). The characteristics of the patients and the tumors are outlined in Table 2. Sixty percent of the cancers were diagnosed in the last 3 years. The age in which the cancers were diagnosed ranged from 5 to 86 years. Of the 10 patients diagnosed with cancer, 6 have died (another patient died in April of this year); the majority of these deaths took place a short time after diagnosis which could suggest either the aggressive nature of the cancer or the delay of the patients in seeking medical help. The patients’ time of residence in San Carlos ranged from 7 to 30 years, with an average time of 17 years.

11 Table 2. Cases of cancer discovered in San Carlos, Orellana, 1989-1998.

a

TYPE of CANCER

ICDa

SEX

C24 C16 C16 C16 C32 C22 172 C42 C77

M M M M M M M M F

Bile ductb Stomach Stomach Stomach Larynx Liver Melanoma Leukemiac Lymphoma

C53

F

Cervix

d

DATE of DIAGNOSIS

AGE at DIAGNOSIS

DATE of DEATH

March 89 June 91 August 92 June 97 Sept. 97 August 98 Nov. 96 July 93 July 96

68 64 55 65 46 86 52 5 28

July 89 July 92 Sept. 92 Oct. 98 Sept. 98 Aug. 97 April 99

May 98

52

-

ICD: International Classification of Diseases. b Others unspecified of the biliar system c Acute lymphoblastic leukemia d Non-Hodgkins lymphoma

3.2

Determination of the standard rate of cancers.

The results of the calculations of the SCR, adjusted according to age, are presented in Table 3. Considering all of the cancer cases, an excess of cancer was found in the male population (8 observed compared to 3.5 expected). This suggests a risk in this population 2.3 times the expected rate, or an excess risk of 130%. Depending on the type of cancer, the male population of San Carlos presents a risk 30 times higher than expected for developing cancer of the larynx; 18 times higher for bile duct cancer; 15 times higher for liver cancer and melanoma, 4.6 times higher for stomach cancer, and 2.6 times higher for leukemia. All of these cancers, except leukemia, are also statistically significant.c In women, after all cancers were considered, an overall excess was not found. However, the risk of lymphoma is 6.7 times higher than expected and the risk of cervical cancer is 2.3 times higher.

c

Statistically significant: indicates that there is higher than 95% probability that the obtained results are not due to chance.

12 Table 3. Incidence of cancer in San Carlos, 1998 (O= number of observed cancers; E= number of expected cancers; SCR=standard cancer rate; CI 95%= confidence interval of 95%). CANCER Stomach Larynx Bile duct Liver Melanoma Leukemia Lymphoma Cervix TOTAL a a

MEN O 3 1 1 1 1 1 8

E 0.64 0.03 0.05 0.06 0.06 0.37 3.5

SCR 4.64 29.9 18 14.5 15.2 2.65 2.3

WOMEN CI 95% 1.5-14.4 4.2-212.5 2.5-127.9 2-102.7 2.1-107.7 0.3-18.8 1.1-4.5

O 1 1 2

E 0.14 0.43 4

SCR 6.7 2.3 0.5

CI 95% 0.9-47.5 0.3-16.2 0.12-1.9

Calculations done with incidence rates of all cancers except skin cancer (C44)

Due to the fact that the majority of the men with cancer had died, using the same method, the number of expected deaths in San Carlos due to cancer was calculated and compared with the number observed deaths. The results of these calculations are presented in Table 4. When total cancers were considered, the number of deaths observed in San Carlos was much higher than the expected rate (6 observed, 1.6 expected). If we divide the results for the different types of cancer, the risk of mortality from stomach cancer is 8 times higher in San Carlos than in Quito, liver cancer mortality is 21 times higher, bile duct cancer mortality is 26.5 times higher, and melanoma mortality is 70 times higher. As stated earlier, this data either suggests the aggressive nature of these tumors or reflects the difficulty posed to the people of San Carlos because of the lack of access to hospitals where they can obtain an early diagnosis. Table 4. Incidence of cancer mortality in San Carlos, 1998 (O= number of observed cancers; E= number of expected cancers; SCR= standard cancer rate; CI 95%= confidence interval of 95%). CANCER Stomach Liver Melanoma Bile duct TOTALa a

MEN O 3 1 1 6

E 0.36 0.046 0.0014 0.037 1.67

SCR 8.21 21.33 69.74 26.57 3.59

Calculations done with incidence rates of all cancers except skin cancer (C44)

CI 95% 2.65-25.46 3-151.44 9.82-495.07 3.74-188.66 1.61-7.99

13

3.3

Evaluation of the environment

The main river that runs through San Carlos is the Huamayacu river. The people use the water of this river for bathing, washing clothing, drinking, and also fishing. In the areas surrounding San Carlos are the Basura river, the Parker river, and other small rivers which are also used by the people of the town. During the month of March 1999, samples were taken from the Huamayacu, Basura, and Parker rivers, and from the Iniap estuary. The samples were taken in the wintertime when there was no visible waste in the rivers. The results are presented in Table 5. In the Iniap estuaries, the concentration of hydrocarbons was more than 10 times the level permitted by the regulations of the European Community, the concentration was 53 times higher in the Parker river, 144 times higher in the Huamayacu, and in the Basura the concentration of hydrocarbons was 288 times the acceptable limit for drinking water. In the 1994 study conducted by the CDES8, high levels of contamination from aromatic polycyclic hydrocarbons were found in the rivers which originate from the Sacha Central pumping station and run through San Carlos. These data further demonstrate the extent to which the residents of this town are exposed to oil contaminants greatly exceeding internationally recognized safety limits, and how this exposure persists throughout the years. Table 5. Concentration of total hydrocarbons (TH)a in the rivers of San Carlos, 1999. IDENTIFICATION Parker River Huamayacu River Basura River Iniap estuary a

TOTAL HYDROCARBONS 0.53 1.444 2.888 0.097

The limit of hydrocarbons permitted in drinking water according to regulations of the European Community is 0.01 parts per million (ppm).

14

4.

What is the significance of these results?

This study has shown that the population of San Carlos is subjected to a much higher risk of developing cancer than should be expected based on the characteristics of the population. The risk in males is particularly high for cancer of the larynx, bile ducts, liver, stomach, melanoma, and leukemia. It is also important to point out the high risk of dying from cancer in this population, especially from cancer of the stomach, liver, bile duct, and melanoma. In women, an excess risk of cervical cancer and lymphoma has been observed. It is suspected that the excess risk of cancer is due to continuous and persistent contamination of the environment by toxins from oil development in the area. This potential association between the occurrence of cancer in San Carlos and the exposure to chemicals from oil wells is supported by the following facts: 1. The high rate of cancer found. The risk of developing certain types of cancer in this population is high enough to suspect the presence of some factor which is contributing to the abnormal elevation. 2. Length of residence The extended time of residence of patients in the area of study implies a possible environmental carcinogenicd because of the long latency period required by most known carcinogens. This fact is supported by the finding that more than half of the cancers were diagnosed in the last 3 years. 3. Length of exposure The association between incidence of cancer and oil contamination is supported by the long history of exposure to oil toxins which the people of San Carlos have suffered. There have been many complaints from residents about oil spills during these twenty years of oil development8,11. 4. The carcinogenic effects of the chemicals. d

Carcinogenic: any biological element capable of triggering the process of cancer formation.

15 It is well known that crude oil and toxic waste from oil stations and wells are highly carcinogenic8. A study conducted on workers in oil fields14 showed an excess of leukemia, and numerous studies conducted on residents near petrochemistry industries have demonstrated an excess in the rate of cancer incidence and cancer mortality15,16,17. However, no study to date had investigated the relationship between cancer incidence and the residence in areas of oil exploitation. 5. Absence of other risk factors. The affected population lacks one of the most common risk factors for cancer: tobacco. As this is a rural population, it also maintains a healthy diet based mainly on the consumption of rice, yuca, plátano, meat (poultry, beef, pork) and occasionally fish, which lowers the risk of cancer. In addition, the population of Quito has also been subjected to the risk of cancer from urban contamination, which would further increase the difference between both populations if we were to eliminate this risk factor. Furthermore, there are no other industries in the area, aside from the oil industry, which could release cancer-causing toxins. 6. The types of cancers found. The majority of cancers found can be explained by the type of exposure that the population has been subjected to. The routes of exposure to toxins released by oil activity mainly include the water and the air. Exposure by way of the air includes migration of the gases from the burning of petroleum and crude oil in wells and stations as well as emission from pools of waste and oil roads. The water route includes contamination of surface water and of underground wells, which causes the contamination of water used domestically by the people. The contamination of the air, water, or land could also affect the consumption of agricultural products and meat. Some of the possible limitations of this study include: 1. The inexactitude of the census of San Carlos, which could cause an imprecise calculation of the expected cancer rate. However, the estimated census of San Carlos was high in order to avoid this type of problem. 2. The reduced number of cases of this grouping of cancers does not permit statistically more convincing analysis that could put in evidence other types of significant differences, which is reflected in the high confidence intervals

16 3. The possibility of having a greater number of cancer cases in San Carlos which have not been diagnosed because access to adequate medical centers for the residents is difficult. 4. The migration of the population could cause a different number of observed cases since individuals with cancer may have moved to other regions. However, if this had occurred, the number of cancers in the San Carlos would be even higher. 5. As with other studies on health and the environment, there is the problem of socioeconomic factors which vary between the areas compared, altering the association between cancer and variable exposure. However, it was not possible to obtain adequate socioeconomic data on the two populations.

5.

Some final recommendations

1. More in-depth studies of cohorts and/or case controls are necessary to confirm the association and obtain more precise information on the risk factors which could be producing the high rate of cancers found in this population. 2. A more extensive study in the area in order to adequately detect all of the possible sources of contamination, eliminate them and establish an adequate monitoring system in the area. As long as the oil contamination persists, the health of this and similar populations will continue to be seriously threatened. 3. Due to the grave nature of cancer, it would be useful to establish an epidemiological monitoring system for the illness which would permit a better understanding of its distribution and its risk factors with the goal of establishing adequate prevention programs.

17

APPENDIX 1 What is known about the impact of oil on health? There are two principal sources of information that can be used to evaluate the health risks of any population exposed to chemicals. The first are studies of toxicity using laboratory animals and the second, studies in human populations.18 Numerous studies have established that the exposure of animals and humans to oil or its components can result in acute health effects (such as skin problems) or even deathly diseases (such as cancer)8. In this appendix we present a bibliographic review of the effects of oil contamination on animals and humans.

1.

Studies on animals

1.1

Laboratory animals

Toxic effects. Studies in birds have shown that ingestion of oil reduces red blood cells as well as white blood cells in primary19 lymphatic organs. The administration of crude oil has also resulted in functional changes in hepatic cells of rats20 and inhibition of testicular development in salmon21. The effects of crude oil produced from the burning of petroleum in Kuwait resulted in diminished survival and growth of the marine fish Menidia beryllina.22 Cancer. Numerous studies report skin tumors in rats following the application of crude oil23-24. Effects on reproduction. The oral administration of crude oil to pregnant rats reduced the weight and length of the fetus and multiple exposure considerably diminished the mother’s weight. Several studies have also demonstrated the pronounced effect of crude oil on the reproductive capacity of birds after its application to the surface of the egg or after oral administration27-30. 1.2

Wild animals

18 Fish. Different studies conducted in marine areas have shown the presence of crude oil in different species of fish following oil spills31,32. The implication of these contaminants for the ecosystems and for the population dependent on them is still not clear. Birds. There is sufficient evidence that oil spills are responsible for massive deaths of marine birds33,34 and the occurrence of hemolytic anemia has been observed in ducks after the ingestion of crude oil35. Mammals. Significant differences in weight and in blood hemoglobin levels occurred in otters inhabiting the contaminated and non-contaminated areas of Prince William Sound (Alaska) after the ExxonValdez oil spill in 1989. An increase in the mortality of seals has also been reported following the oil spills in the North Sea36. In areas of oil production, the proximity of cattle to the drilling and production sites often results in poisoning of the animals from ingestion of crude oil, salt water, heavy metals, and caustic chemicals. The most common cause of illness or death following the exposure to oil particles is pneumonia from breathing it in, which can cause a chronic deterioration of health, with death occurring after several days or weeks37,38. 2.

Studies on humans

Oil production can negatively infringe upon the health of the population in every phase of its cycle. In this section, due to its implications for the area of study, its impact on health is described in relation to the initial seismic studies, drilling, production, and finally transport. In addition, oil exposure is not limited to the areas close to the contamination. When oil contaminates the environment, the heaviest particles tend to be deposited in the sediment from where they can repeatedly contaminate water sources or be consumed by organisms that can enter the human food chain. Lighter oil components can evaporate within hours and be deposited by air or water at great distances from where they were produced8. Oil or its components can enter into contact with the human body in three ways: • absorption through the skin

19 • ingestion of food and water • inhalation of oil and its gases The inhabitants of oil production areas of the Oriente are faced with potential exposure by any of these three routes. 2.1

Exploration phase

We have not found literature about the health effects during this phase. However, in the context of Ecuador, exploration workers have reported low salaries and poor conditions of life and work; illnesses related to the work as well as skin diseases and gastrointestinal diseases are frequent39. Yellow fever was contracted by many workers (one died) due to penetration into the jungle without adequate protection with the vaccine (personal observation). Many workers are Indians and their entrance into this world of migratory work has severed traditional family life and sparked epidemics of influenza, malaria, hepatitis, and venereal diseases in their communities (Amunárriz, personal communication). 2.2

Drilling / Production phase

Activities associated with this phase produce a great variety of contaminants in the soil, the water, and the air. The communities that live close to the oil wells have a greater probability of suffering exposure to chemicals and toxins when they breathe, use water for drinking, bathing, or cooking, and eat food that has been in contact with the toxins. The contaminants of crude oil can be deposited in the earth or ingested through aquatic organisms in quantities that can have adverse effects on health and increase rates of malnutrition, especially in children and fishermen, when contaminated fish or their products enter the food chain40. Sathiakumar et al.14 conducted an epidemiological study on oil and gas field workers and found an association between their work and acute myeloid leukemia.

20 The drilling and production phases also carry the risk of accidents41. Furthermore, the oil industry exposes workers to high levels of noise from drills, compressors, generators, etc.42 Currently, three groups of chemical exposure merit a more detailed explanation. 2.2.1.

Crude oil

Crude oil has been defined as a complex mixture, composed primarily of paraphenol, aromatic hydrocarbons, and particles of other elements including various metals. Among the identified components of crude oil, the aromatic hydrocarbons of toxicological interest are alka-benzols (mainly toluene and xylene) and the polynuclear aromatic hydrocarbons43. The effects of acute exposure to crude oil on humans are usually transient and of short duration unless the concentration of the components is unusually high. Such exposures irritate the skin, cause itchiness or irritation of the eyes from accidental contact or exposure to the vapors, and can cause nausea, vertigo, headache, or dizziness from prolonged or repeated exposure to low concentrations of its volatile components44. Inhalation of mineral oils can cause lipoid pneumonia and death45. Of particular concern is exposure to benzene, toluene and xylene. High concentrations of benzene cause neurotoxic symptoms, and a prolonged exposure to toxic levels can cause lesions of the bone marrow46. The primary effects of toluene and xylene are on the central nervous system. There is not sufficient data on the incidence of cancer following human exposure to these toxins. There is also no evidence of birth defects due to benzene, toluene, or xylene.44 Due to its elevated carcinogenic effects and long persistance in the environment, benzopyrene seems to be the most important risk factor and most relevant indicator of crude oil contamination. Adequate data on which to base a quantitative evaluation on the risk of cancer following the ingestion of HAP are only available for BaP47,48. There is little information available about the oral toxicity of the HAPs, especially after exposure of long duration.

21 2.2.2.

Other chemical exposure

The oil companies in Ecuador have not informed the public of the chemical data related to waste from oil drilling. Data from the U.S. show that the waste from drilling can contain significant quantities of a wide variety of contaminants such as antimony, arsenic, cadmium, chrome, lead, magnesium, zinc, benzene and other hydrocarbons as well as toxic levels of sodium and chloride2. The heavy metals which pose a threat to health from oil exposure through drinking water are mercury and cadmium. Exposure to mercury occurs through contaminated surface water or underground water or from fish consumption49. Similarly, the components of alka-mercury are liposoluble and volatile; therefore they carry the risk of being absorbed by the skin or inhaled when bathing in contaminated waters50. The most common symptoms from mercury poisoning are disordered thinking, difficulty walking and talking, tunnel vision, and difficulty chewing and swallowing51. The toxicological implications of exposure to low concentrations of mercury are still not well understood. Cadmium accumulates throughout one’s life. Environmental exposure to cadmium can occur, as in the case of mercury, through water or food consumption. Individuals in Japan who consumed rice contaminated with cadmium developed chronic cadmium poisoning and a reduced life expectancy52. Elevated consumption of cadmium produces nausea, vomiting, abdominal pain, diarrhea, and renal disease. Recent studies have suggested an increase in lung cancer mortality in workers exposed to cadmium54. Other studies have also indicated an association between the level of cadmium in drinking water and prostate cancer.55 2.2.3.

Air contamination

Air contamination with chemical or solid agents is one of the consequences of drilling oil. The degree to which the contaminants emitted into the air contain a risk for the general population depends on various factors; some of these include the type and quantity of compounds released, the condition of the atmosphere, the number of people exposed and their susceptibility. The burning of oil and gas contaminates the air with oxides of nitrogen, sulfur, and carbon (CO), as well as with heavy metals , hydrocarbons and

22 diverse particles of carbon. Many of these emissions are toxic, and the oxides of nitrogen can react with solar light to form ozone, an irritant to the human respiratory tract. Although quantitative data on air emissions from oil operations are not available in Ecuador – at least to the public- an internal study by Petroecuador found that the levels of contaminated air were alarming2. Numerous studies have demonstrated the relationship between exposure to these contaminants and bronco-constrictive effects56, documenting asthmatic responses in adults as well as in children57. Other studies have also associated an increase in mortality with air contamination58,59. Investigations of the exposure to ozone and nitrogen dioxide have revealed symptoms and changes in respiratory mechanisms, bronco-constriction and pulmonary edema60. The clinical effects of acute carbon poisoning vary with the level of intoxication, from non-specific symptoms (headache, dizziness, fatigue) to death61. Chronic exposure to carbon, at low doses, can affect the coagulation system increasing the risk of thromboembolism in the heart or brain62. Along with these contaminants, the populations exposed to HAP and volatile organic compounds in the air are at risk for lung cancer63 and adverse respiratory effects64 respectively. 2.3

Transport

The accumulation of water during the construction of roads is inevitable. Mosquitoes carrying malaria proliferate in these surface waters, increasing the spread of the disease. In 1974, more the 50% of the malaria of the Brazilian Amazon was associated with the narrow area of influence of the TransAmazon highway65. Many of the roads of the Oriente are without asphalt and great quantities of dust from traffic can cause respiratory diseases66. Where the roads are covered with crude oil, there is often an intense odor, and skin problems occur when people walk barefoot. There also seems to be a strong association between this development and the mortality related to vehicles67. On the roads of the Oriente, car accidents are

23 numerous, and are becoming the second highest cause of mortality in small cities68.

2.4

Oil spills

Epidemiological investigations of the great oil spills have not been frequently carried out and have concentrated more on workers involved in the clean-up operations than on the residents of the areas. These studies have also only been carried out long after the incidents occurred69. One study conducted a year after the 1989 Exxon Valdez oil spill off the coast of Alaska suggested an increase in anxiety attacks, post-traumatic stress disorder, and depressive symptoms in the affected communities after the spill. The populations most at risk for these conditions were women and Indians70. Another study evaluating the immediate and posterior effects on health after the oil spill of the Braer tanker off the coast of Shetland (United Kingdom) was conducted in 1993; anecdotal reports of acute symptoms without significant differences were found in the exposed population during the initial phase of study and no differences in the health of the exposed population and the non-contaminated population were found 6 months later44,71.

24

APPENDIX 2 Calculation of the standard rate of cancer incidence by age and sex The standard cancer rate (SCR) is calculated by dividing the number of observed cancer cases in the study population by the number of expected cancers in the same population. To determine the number of expected cancers, the number of person/years corresponding to the age distribution of the study population is multiplied by the cancer rate of the reference population corresponding to the same age distribution. The age-adjusted calculation of the SCR is illustrated below for tumors of the larynx.

AGE GROUP

0-4 5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 >75

OBSERVED CANCER

STANDARD RATE (100,000)

0 0 0 0 0 0 0 0.4 1.1 1 0.8 1.5 5.1 6.9 4.2 12.9 22.5 1 SCR = Observed/Expected = 1/0.03341 = 29.93

POPULATION/ YEARS

EXPECTED CANCER

940 900 750 580 470 400 330 320 230 160 140 90 70 40 30 50

0 0 0 0 0 0 0 0.00128 0.00253 0.00128 0.00210 0.00459 0.00483 0.00168 0.00387 0.01125 0.03341

25

APPENDIX 3 Estimated distribution of the populationa of San Carlos by age groups. MALE POPULATION: 550 FEMALE POPULATION: 450 AGE GROUP 0-4 5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 >75 TOTAL a

% 17 16.4 13.5 10.4 8.6 7.2 5.9 5.7 4.2 2.9 2.6 1.6 1.2 0.76 0.58 0.83

MALES 94 90 75 58 47 40 33 32 23 16 14 9 7 4 3 5 550

FEMALES 77 74 61 47 39 33 27 26 19 13 12 7 6 3 2 4 450

The percentage of the population is based on estimates of the National Institute of Statistics and Census for the rural population of Joya de los Sachas for the year 1998

26

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