Exposures and cancer incidence near oil fields in the Amazon basin of Ecuador

Heavy Metal Contamination in Birds from Protected Regions in the Amazon

The extraction of crude oil and gold has substantially increased heavy metal contamination in the environment, yet the study of wildlife exposure and biological response to this pollution remains nascent even in the most biodiverse places in the world. We present a survey of heavy metal exposure in the feathers of wedge-billed woodcreepers (Glyphorynchus spirurus), a resident neotropical bird found within protected regions of the Amazon near oil and gold extraction sites. Our results show elevated heavy metal contamination in samples collected from protected areas proximate to known oil and gold extraction. Surprisingly, several samples from remote reference sites also displayed elevated levels of various heavy metals, suggesting a background of natural deposition or complex heavy metal contamination in the environment from anthropogenic sources. These results highlight the need to understand the ecological and biological impacts of increased heavy metal exposure on wildlife across space and time, including remote regions of the world purportedly untouched by these human-mediated stressors. Toward this goal, historical and contemporary data from native bird populations may provide crucial indicators for heavy metal contamination and exposure in wildlife and human communities. Environ Toxicol Chem 2024;43:2601-2607. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Spatial distribution of total petroleum hydrocarbons in the seawater and sediment of Southeast coast of India

The spatial distribution of total petroleum hydrocarbons (TPH) were analysed in the seawater and sediment samples collected from 27 locations along the Southeast coast of India. A first-time assessment was carried out on the distribution of TPH in both water and sediments for the entire coastline of Tamil Nadu. The concentration of TPH in seawater showed large spatial variation ranging from below detection level (BDL) to 47.5 μg/L and 0.01 to 53.12 μg/L in the surface and bottom waters, respectively. TPH levels exceeded the regulatory limits specified by FAO, China's Marine Monitoring Standards and the European Community in the seawater samples of Thoothukudi harbour (S2 station). The results showed that seawaters of southern stations were comparatively more polluted with TPH. TPH values in sediment were between 2.33 and 30.07 μg/g, and their levels remained below the Marine Sediment Quality Standard (500 μg/g). The spatial profile of TPH in sediments were contrasting to that observed for seawater. Higher TPH values were observed in sediments of the northern region than southern. TPH contents are strongly correlated with clay (R2 = 0.776; P < 0.001) and silt (R2 = 0.648; P < 0.001); conversely, there is a significant negative correlation between TPH and sand (R2 = 0.753; P < 0.001). ANOVA analysis demonstrated a significant difference (F = 11.75; p < 0.01) between the TPH concentrations of water and sediments. Non-metric multidimensional scaling (nMDS) was performed to determine the similarity among sampling stations that formed five crusted groups. Sediment along the southeast coast can be categorised as slightly polluted with respect to TPH as per the ATSDR standards.

Genetic Instability among Hitnü People Living in Colombian Crude-Oil Exploitation Areas

Oil exploitation, drilling, transportation, and processing in refineries produces a complex mixture of chemical compounds, including polycyclic aromatic hydrocarbons (PAHs), which may affect the health of populations living in the zone of influence of mining activities (PZOI). Thus, to better understand the effects of oil exploitation activities on cytogenetic endpoint frequency, we conducted a biomonitoring study in the Hitnü indigenous populations from eastern Colombia by using the cytokinesis micronucleus cytome assay (CBMN-cyt). PAH exposure was also measured by determine urine 1-hydroxypyrene (1-OHP) using HPLC. We also evaluated the relationship between DNA damage and 1-OHP levels in the oil exploitation area, as well as the modulating effects of community health factors, such as Chagas infection; nutritional status; and consumption of traditional hallucinogens, tobacco, and wine from traditional palms. The frequencies of the CBMN-cyt assay parameters were comparable between PZOI and Hitnü populations outside the zone of influence of mining activities (POZOI); however, a non-significant incremental trend among individuals from the PZOI for most of the DNA damage parameters was also observed. In agreement with these observations, levels of 1-OHP were also identified as a risk factor for increased MN frequency (PR = 1.20) compared to POZOI (PR = 0.7). Proximity to oil exploitation areas also constituted a risk factor for elevated frequencies of nucleoplasmic bridges (NPBs) and APOP-type cell death. Our results suggest that genetic instability and its potential effects among Hitnü individuals from PZOI and POZOI could be modulated by the combination of multiple factors, including the levels of 1-OHP in urine, malnutrition, and some traditional consumption practices.

Effects of cadmium contamination on bacterial and fungal communities in Panax ginseng-growing soil

Background

Cadmium (Cd) contamination in soil poses a serious safety risk for the development of medicine and food with ginseng as the raw material. Microorganisms are key players in the functioning and service of soil ecosystems, but the effects of Cd-contaminated ginseng growth on these microorganisms is still poorly understood. To study this hypothesis, we evaluated the effects of microorganisms and Cd (0, 0.25, 0.5, 1.0, 2.0, 5.0, and 10.0 mg kg^-1 of Cd) exposure on the soil microbial community using Illumina HiSeq high-throughput sequencing.

Results

Our results indicated that Cd-contaminated soil affected the soil microbial diversity and composition, and bacterial diversity was affected more than fungal diversity in Cd-contaminated soil, especially according to Shannon indices. The abundance of the soil microbial community decreased and the composition changed according to the relative abundances at the phylum level, including those of Saccharibacteria and Gemmatimonadetes in bacteria and Mortierellomycota in fungi. The LEfSe algorithm was used to identify active biomarkers, and 45 differentially abundant bacterial taxonomic clades and 16 differentially abundant fungal taxonomic clades were identified with LDA scores higher than 4.0. Finally, a heatmap of Spearman's rank correlation coefficients and canonical discriminant analysis (CDA) indicated that some key biomarkers, Arenimonas, Xanthomonadales, Nitrosomonadaceae, Methylophilales, Caulobacterales, Aeromicrobium, Chitinophagaceae, Acidimicrobiales, Nocardioidaceae, Propionibacteriales, Frankiales, and Gemmatimonadaceae, were positively correlated with the total and available Cd (p<0.05) but negatively correlated with AK, AP, and pH (p<0.05) in the bacterial community. Similarly, in the fungal community, Tubaria, Mortierellaceae, and Rhizophagus were positively correlated with the total and available Cd but negatively correlated with AK, AP, TK, and pH.

Conclusion

Cd contamination significantly affected microbial diversity and composition in ginseng-growing soil. Our findings provide new insight into the effects of Cd contamination on the microbial communities in ginseng-growing soil.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02488-z.

Is the anemia in men an effect of the risk of crude oil contamination?

Pollution from oil spills can seriously affect many ecosystem processes and human health. Many articles have evaluated the impact of oil spills on human health. However, most of these articles focus on occupational exposure. The effect on people living in the areas affected by oil pollution is rarely studied. Approximately 640 million people worldwide live in areas at risk of oil pollution. Thus, studying the impact of this pollution on human health should be a priority. Here, we evaluate the presence of anemia in relation to crude oil exposure in men living in areas at risk of oil contamination in the Ecuadorian Amazon (Orellana and Napo). We evaluated the hematological and biochemical parameters of 135 participants. We divided the participants into three groups according to exposure: low, medium, and high. Our results showed a significant association between exposure risk and hemoglobin and hematocrit concentration. Groups with medium- and high- contamination exposure had levels below normal values in hemoglobin and hematocrit in more than 30% and 26% of the population, respectively. In conclusion, we found that crude oil affected human health, and the prevalence of the anemia in men was dependent of the level of contamination.

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Biochemical and hematological parameters were analyzed of population of Amazon of Ecuador.

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A relationship between exposure to crude oil and anemia in men was observed.

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GLM did not show effects on monocytes, granulocytes, lymphocytes, or red blood cells.

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OR significant effects of the level of risk on hematocrit were evidenced.

Exploring the Link between Oil Exploitation and Cancer in the Indigenous Population of Ecuador: A Scoping Review

With cancer accounting for 19% of deaths and projected to rise in the coming years, Ecuador's inequities in healthcare coverage remain a major concern for the rural, indigenous populations. While the cancer burden among this vulnerable population has been much publicized in the context of the controversial oil extraction in the Amazon, there is contradictory evidence on its occurrence and determinants. This review critically discusses the available literature on cancer among indigenous people in Ecuador and explores the link between oil exploitation and cancer occurrence among indigenous people using a scoping review approach. The results of this review show there is a clear but inconsistent association between oil exposure and cancer risk in indigenous populations of Ecuador. While the environmental magnitude of oil extraction in this region is a topic of debate, our findings point to the interplay with social determinants and other sources of carcinogenic compounds, which exacerbates the risks faced by indigenous communities. Based on these findings, this study puts forward three arguments to contextualize the occurrence of cancer related to oil exploitation in the Amazon, and puts forth key recommendations for public health initiatives embedded within the local community.

Evaluation of genotoxic damage in buccal mucosa cytome assays in Iraqi school children exposed to air pollutants emanating from oil fields

Presently, over 135 thousand barrels of crude oil are extracted daily from the Al-ahdeb oil fields (situated at 180 km south east of Baghdad, Iraq). Millions of gallons of untreated toxic wastes, gas and crude oil are released into the environment. Oil mining mediated pollution may cause damage to humans and the environment. To investigate potential health risks for children living in this area, we recruited a sample of 6-8 year old school children residing within a 5 km radius around the oil field, and a control sample of children of the same age from a school 40 km away from the oil-field. Exfoliated buccal mucosa cells obtained from these children were analyzed applying the micronucleus (MN) cytome assay. Possible confounding variables such as x-rays performed during three weeks preceding sampling were obtained by a questionnaire. Nuclear anomalies were significantly elevated in children living near the oil-field. Micronucleated cells 1.3-fold, nuclear buds 3-folds, binucleated cells 3-folds, karyorrhetic cells 4-folds and karyolysis more than 10 folds with a significant difference (P < 0.05). Hence, children living in the proximity of Iraqi oil-fields are at elevated risk of genetic damage, which can cause detrimental health effects in the future.

Is this a Real Choice? Critical Exploration of the Social License to Operate in the Oil Extraction Context of the Ecuadorian Amazon

The purpose of this research was to critically analyze the social license to operate (SLO) for an oil company operating in Block 10, an oil concession located in the Ecuadorian Amazon. The specific study area is an important biodiversity hotspot, inhabited by indigenous villages. A mixed-methods approach was used to support a deeper understanding of SLO, grounded in participants’ direct experience. Semi-structured interviews (N = 53) were conducted with village leaders and members, indigenous associations, State institutions, and oil company staff, while household surveys were conducted with village residents (N = 346). The qualitative data informed a modified version of Moffat and Zhang’s SLO model, which was tested through structural equation modelling (SEM) analyses. Compared to the reference model, our findings revealed a more crucial role of procedural fairness in building community trust, as well as acceptance and approval of the company. Procedural fairness was found to be central in mediating the relationship between trust and the effects of essential services provided by the company (medical assistance, education, house availability) and sources of livelihoods (i.e., fishing, hunting, harvesting, cultivating, and waterway quality). The main results suggested that the concept of SLO may not appropriately apply without taking into account a community’s autonomy to decline company operation. To enhance procedural fairness and respect for the right of community self-determination, companies may need to consider the following: Establishing a meaningful and transparent dialogue with the local community; engaging the community in decision-making processes; enhancing fair distribution of project benefits; and properly addressing community concerns, even in the form of protests. The respect of the free prior informed consent procedure is also needed, through the collaboration of both the State and companies. The reduction of community dependence on companies (e.g., through the presence of developmental alternatives to oil extraction) is another important requirement to support an authentic SLO in the study area.

Emissions of volatile organic compounds from crude oil processing - Global emission inventory and environmental release

Airborne Volatile organic compounds (VOCs) are known to have strong and adverse impacts on human health and the environment by contributing to the formation of tropospheric ozone. VOCs can escape during various stages of crude oil processing, from extraction to refinery, hence the crude oil industry is recognised as one of the major sources of VOC release into the environment. In the last few decades, volatile emissions from crude oil have been investigated either directly by means of laboratory and field-based analyses, or indirectly via emission inventories (EIs) which have been used to develop regulatory and controlling measures in the petroleum industry. There is a vast amount of scattered data in the literature for both regional emissions from crude oil processing and scientific measurements of VOC releases. This paper aims to provide a critical analysis of the overall scale of global emissions of VOCs from all stages of oil processing based on data reported in the literature. The volatile compounds, identified via EIs of the crude oil industry or through direct emissions from oil mass, are collected and analysed to present a global-scale evaluation of type, average concentration and detection frequency of the most prevalent VOCs. We provide a critical analysis on the total averages of VOCs and key pieces of evidence which highlights the necessity of implementing control measures to regulate crude oil volatile emissions (CVEs) in primary steps of extraction-to-refinery pathways of crude oil processing. We have identified knowledge gaps in this field which are of importance to control the release of VOCs from crude oil, independent of oil type, location, operating conditions and metrological parameters.

Viral hepatitis in the Peruvian Amazon: Ethnomedical context and phytomedical resource

ETHNOPHARMACOLOGICAL RELEVANCE

An extensive ethnopharmacological survey was carried out in the Peruvian Amazonian district of Loreto with informants of various cultural origins from the surroundings of Iquitos (capital city of Loreto) and from 15 isolated riverine Quechua communities of the Pastaza River. A close attention was paid to the medical context and plant therapy, leading to the selection of 35 plant species (45 extracts). The extracts were tested for antiviral activity against HCV with counting of Huh-7 cellular death in case of toxicity, and cytotoxicity was evaluated in HepG2 cells.

AIM OF THE STUDY

The aim of the study was to inventory the plants used against hepatitis in Loreto, then to evaluate their antiviral activity and to suggest a way to improve local therapeutic strategy against viral hepatitis, which is a fatal disease that is still increasing in this area.

MATERIALS AND METHODS

An ethnographic survey was carried out using "participant-observation" methodology and focusing on plant therapy against hepatitis including associated remedies. 45 parts of plant were extracted with methanol and tested in vitro for anti-HCV activity in 96-well plate, using HCV cell culture system with immunofluorescent detection assisted by automated confocal microscopy. Toxicity of plant extracts was also evaluated in microplates on hepatic cells by immunofluorescent detection, for the Huh-7 nuclei viability, and by UV-absorbance measurement of MTT formazan for cytotoxicity in HepG2 cells.

RESULTS

In vitro assay revealed interesting activity of 18 extracts (50% infection inhibition at 25 μg/mL) with low cytotoxicity for 15 of them. Result analysis showed that at least 30% of HCV virus were inhibited at 25 μg/mL for 60% of the plant extracts. Moreover, the ethnomedical survey showed that remedies used with low and accurate dosing as targeted therapy against hepatitis are usually more active than species indicated with more flexible dosing to alleviate symptoms of hepatic diseases.

CONCLUSION

Together with bibliographic data analysis, this study supported the traditional medicinal uses of many plants and contributed to a better understanding of the local medical system. It also permitted to refine the therapeutic plant indications regarding patients' liver injuries and vulnerability. Only 2 of the 15 most active plant species have already been studied for antiviral activity against hepatitis suggesting new avenues to be followed for the 13 other species.

Public health issues from crude-oil production in the Ecuadorian Amazon territories

Crude oil production (COP) is a high-pollution industry but the vast Amazon rainforest has been an active COP zone for South America. Although COP has been associated with a variety of health effects among workers around the world, such effects have not been adequately investigated in the Amazon region, especially at the community level. Therefore, this review was conducted to provide a report about COP in the Amazon of Ecuador and about its association with health status of indigenous human populations. Some epidemiological surveys in the Amazonian Territories indicate that COP has been associated with health problems in the surrounding populations, e.g. cancers in the stomach, rectum, skin, soft tissue, kidney and cervix in adults, and leukemia in children. In addition, some biomarkers and mechanistic studies show exposure effects. However, due to limitations from these studies, contradictory associations have been reported. Our review indicates that COP in the Amazonian territories of northern Ecuador was characterised by contamination which could have affected the indigenous and non-indigenous populations. However, there have not been dedicated investigations to provide relationships between the contamination and the subsequent exposure-health effects. Since indigenous populations have different lifestyle and cultures from regular city dwellers, systematic studies on their potential health hazards need to be conducted. Due to the remote locations and sparse populations, these new studies may involve the use of novel and genomic-based biomarkers as well as using high technology in the remote regions.

A State-of-the-Art Review of Indigenous Peoples and Environmental Pollution

Indigenous peoples (IPs) worldwide are confronted by the increasing threat of pollution. Based on a comprehensive review of the literature (n = 686 studies), we present the current state of knowledge on: 1) the exposure and vulnerability of IPs to pollution; 2) the environmental, health, and cultural impacts of pollution upon IPs; and 3) IPs' contributions to prevent, control, limit, and abate pollution from local to global scales. Indigenous peoples experience large burdens of environmental pollution linked to the expansion of commodity frontiers and industrial development, including agricultural, mining, and extractive industries, as well as urban growth, waste dumping, and infrastructure and energy development. Nevertheless, IPs are contributing to limit pollution in different ways, including through environmental monitoring and global policy advocacy, as well as through local resistance toward polluting activities. This work adds to growing evidence of the breadth and depth of environmental injustices faced by IPs worldwide, and we conclude by highlighting the need to increase IPs' engagement in environmental decision-making regarding pollution control. Integr Environ Assess Manag 2020;16:324-341. © 2019 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Unburnable and Unleakable Carbon in Western Amazon: Using VIIRS Nightfire Data to Map Gas Flaring and Policy Compliance in the Yasuní Biosphere Reserve

In the Amazon Rainforest, a unique post-carbon plan to mitigate global warming and to protect the exceptional bio-cultural diversity was experimented in 2007–2013 by the Ecuadorian government. To preserve the rainforest ecosystems within the Yasuní-ITT oil block, the release of 410 million metric tons of CO2 would have been avoided. The neologism “yasunization” emerged as an Amazonian narrative on “unburnable carbon” to be replicated worldwide. Considering the unburnable carbon, petroleum-associated gas flaring represents the unleakable part. Flaring is an irrational practice that consists of burning waste gases, representing not only a leak of energy but also a pollution source. The general aim of the paper is to monitor gas flaring as a tool, revealing, at the same time, the implementation of environmental technologies in the oil sector and the compliance of sustainable policies in the Amazon region and the Yasuní Biosphere Reserve. Specific objectives are: (i) identifying and estimating gas flaring over seven years (2012–2018); (ii) mapping new flaring sites; iii) estimating potentially affected areas among ecosystems and local communities. We processed National Oceanic and Atmospheric Administration (NOAA) Nightfire annual dataset, based on the elaboration of imagery from the Visible Infrared Imaging Radiometer Suite (VIIRS) and developed a GIS-based novel simple method to identify new flaring sites from daily detections. We found that 23.5% of gas flaring sites and 18.4% of volumes of all oil industries operating in Ecuador are located within the Yasuní Biosphere Reserve (YBR). Moreover, we detected 34 additional flaring sites not included in the NOAA dataset—12 in the YBR and one in Tiputini field, a key area for biological and cultural diversity conservation. We also found that at least 10 indigenous communities, 18 populated centers and 10 schools are located in the potentially affected area. Gas flaring can be used as a policy indicator to monitor the implementation of sustainable development practices in complex territories.

Drinking water quality in areas impacted by oil activities in Ecuador: Associated health risks and social perception of human exposure

The unregulated oil exploitation in the Northern Ecuadorian Amazon Region (NEAR), mainly from 1964 to the 90's, led to toxic compounds largely released into the environment. A large majority of people living in the Amazon region have no access to drinking water distribution systems and collects water from rain, wells or small streams. The concentrations of major ions, trace elements, PAHs (polycyclic aromatic hydrocarbons) and BTEX (benzene, toluene, ethylbenzene, xylenes) were analyzed in different water sources to evaluate the impacts of oil extraction and refining. Samples were taken from the NEAR and around the main refinery of the country (Esmeraldas Oil Refinery/State Oil Company of Ecuador) and were compared with domestic waters from the Southern region, not affected by petroleum activities. In most of the samples, microbiological analysis revealed a high level of coliforms representing significant health risks. All measured chemical compounds in waters were in line with national and international guidelines, except for manganese, zinc and aluminum. In several deep-water wells, close to oil camps, toluene concentrations were higher than the natural background while PAHs concentrations never exceeded individually 2 ng·L^-1. Water ingestion represented 99% of the total exposure pathways for carcinogenic and non-carcinogenic elements (mainly zinc) in adults and children, while 20% to 49% of the Total Cancer Risk was caused by arsenic concentrations. The health index (HI) indicates acceptable chronic effects for domestic use according the US-EPA thresholds. Nevertheless, these limits do not consider the cocktail effects of metallic and organic compounds. Furthermore, they do not include the social determinants of human exposure, such as socio-economic living conditions or vulnerability. Most (72%) of interviewed families knew sanitary risks but a discrepancy was observed between knowledge and action: religious beliefs, cultural patterns, information sources, experience and emotions play an important role front to exposure.

[Cancer mortality among indigenous population in Acre State, Brazil]

The study aimed to estimate cancer mortality among indigenous peoples in Acre State, Brazil. This was a descriptive observational study based on the nominal bank of the Brazilian Mortality Information System for the period from January 1st, 2000, to December 31st, 2012. The study analyzed the distribution death frequencies by sex and age. Standardized mortality ratio (SMR) was calculated taking Goiânia (Goiás State), Acre State, and the North Region of Brazil as the references. A total of 81 deaths were identified, the majority in men (59.3%) and in individuals over 70 years of age. The five main sites in men were stomach, liver, colon and rectum, leukemia, and prostate. The five main sites in women were uterine cervix, stomach, liver, leukemia, and uterus. In indigenous men there was an excess of deaths from stomach cancer compared to the populations of Goiânia (SMR = 2.72; 2.58-2.87), Acre State (SMR = 2.05; 1.94-2.16) and North region (SMR = 3.10; 2.93-3.27). The same was observed for deaths from hepatic cell carcinomas referenced against Goiânia (SMR = 3.89; 3.66-4.14), Acre State (SMR = 1.79; 1.68-1.91), and the North of Brazil (SMR = 4.04; 3.77-4.30). Among indigenous women, there was an excess of cervical cancer in comparison to Goiânia (SMR = 4.67; 4.41-4.93), Acre State (SMR = 2.12; 2.00-2.24), and the North (SMR = 2.60; 2.45-2.75). The estimates show that preventable neoplasms such as cervical cancer and those linked to underdevelopment, such as stomach and liver cancer, account for 49.4% of deaths among indigenous peoples. Compared to the reference population, mortality from liver, stomach, and colorectal cancer and leukemias was more than twice as high in indigenous men; among indigenous women, cervical, stomach, and liver cancer and leukemias were 30% higher.

Impact of upstream oil extraction and environmental public health: A review of the evidence

Upstream oil extraction, which includes exploration and operation to bring crude oil to the surface, frequently occurs near human populations. There are approximately 40,000 oil fields globally and 6 million people that live or work nearby. Oil extraction can impact local soil, water, and air, which in turn can influence community health. As oil resources are increasingly being extracted near human populations, we highlight the current scope of scientific knowledge regarding potential community health impacts with the aim to help identify scientific gaps and inform policy discussions surrounding oil drilling operations. In this review, we assess the wide range of both direct and indirect impacts that oil drilling operations can have on human health, with specific emphasis on understanding the body of scientific literature to assess potential environmental and health risks to residents living near active onshore oil extraction sites. From an initial literature search capturing 2236 studies, we identified 22 human studies, including 5 occupational studies, 5 animal studies, 6 experimental studies and 31 oil drilling-related exposure studies relevant to the scope of this review. The current evidence suggests potential health impacts due to exposure to upstream oil extraction, such as cancer, liver damage, immunodeficiency, and neurological symptoms. Adverse impacts to soil, air, and water quality in oil drilling regions were also identified. Improved characterization of exposures by community health studies and further study of the chemical mixtures associated with oil extraction will be critical to determining the full range of health risks to communities living near oil extraction.

Spatial Analysis of Accidental Oil Spills Using Heterogeneous Data: A Case Study from the North-Eastern Ecuadorian Amazon

Accidental oil spills were assessed in the north-eastern Ecuadorian Amazon, a rich biodiversity and cultural heritage area. Institutional reports were used to estimate oil spill volumes over the period 2001–2011. However, we had to make with heterogeneous and incomplete data. After statistically discriminating well- and poorly-documented oil blocks, some spill factors were derived from the former to spatially allocate oil spills where fragmentary data were available. Spatial prediction accuracy was assessed using similarity metrics in a cross-validation approach. Results showed 464 spill events (42.2/year), accounting for 10,000.2 t of crude oil, equivalent to annual discharges of 909.1 (±SD = 1219.5) t. Total spill volumes increased by 54.8% when spill factors were used to perform allocation to poorly-documented blocks. Resulting maps displayed pollution ‘hotspots’ in Dayuma and Joya de Los Sachas, with the highest inputs averaging 13.8 t km−2 year−1. The accuracy of spatial prediction ranged from 32 to 97%, depending on the metric and the weight given to double-zeros. Simulated situations showed that estimation accuracy depends on variabilities in incident occurrences and in spill volumes per incident. Our method is suitable for mapping hazards and risks in sensitive ecosystems, particularly in areas where incomplete data hinder this process.

Elevated Indoor Volatile Organic Compound Exposure in the Niger Delta Region of Nigeria

The implications of environmental contamination on human health in the Niger Delta region of Nigeria remain a topic of growing international public health interest. To better understand ongoing air pollution and initiate remediation efforts, the United Nations Environmental Programme (UNEP) report recommended the monitoring of volatile organic compounds (VOCs) across different media (water, soil, and air) in Ogoniland, an at-risk population in the Niger Delta region of Nigeria. In this pilot study, we measured indoor VOC concentrations in the indoor air of 20 households in Ogale, an Ogoniland community whose groundwater system is contaminated with benzene at levels 900 times the World Health Organization guidelines and evaluated self-reported health conditions and predicted cancer risks and hazards from inhalation exposure to VOCs. We detected higher concentrations of benzene (mean = 25.7 μg/m³, SD = 23.2 μg/m³) and naphthalene (mean = 7.6 μg/m³, SD = 13.8 μg/m³) than has been reported in other regions. Although study participants reported health symptoms consistent with VOC exposure, we were underpowered to detect a significant association between select indoor VOCs and these self-reported health symptoms using univariate logistic regression models. These findings suggest that that the health symptoms reported by participants may be poor proxies for the underlying disease processes associated with adverse health outcomes due to VOC exposure in this community and that the burden of adverse health effects due to VOC exposure may stem from the contaminated groundwater system. We estimated a non-cancer hazard quotient of 3 from exposure to naphthalene and lifetime excess cancer risks from exposure to naphthalene, benzene, p-dichlorobenzene, carbon tetrachloride, and ethylbenzene of 3 × 10⁻⁴, 2 × 10⁻⁴, 6 × 10⁻⁵, 6 × 10⁻⁶, and 1 × 10⁻⁵, respectively. These results exceed common risk benchmarks in the United States, suggesting a need for further studies to characterize VOC exposures, sources, and associated health risks in the Niger Delta.

Dirty hands: The toxic politics of denunciation

In September 2013, President Correa balanced himself on a felled log over an oil waste pit in the Ecuadorian Amazon. Extending a bare hand dripping with crude, he launched La Mano Sucia de Chevron campaign, demanding accountability for decades of contamination. This article explores the role of bodily knowledge in witnessing industrial contamination and struggles for environmental justice. Situating the mano sucia in the history of activism in the region, I show how the juxtaposition of different hands within the same motif reveals profoundly asymmetric relationships to the toxic entanglements that oil produces. Dirtied hands reveal the co-production of toxicity and power in extractive landscapes: At times throughout this article, the gesture calls for corporate accountability and distributive environmental justice, at other times, it reveals the systemic production of material, social and political distance between the accrual of benefit and the production of harm in an industrial-capitalist order. While drawing on the central role of bodily knowledges in apprehending environmental harm, I argue that bodily knowledges must also be examined for their specific relationships to forms of power and exploitation, and for their potential for appropriation by other parties - even when dedicated to condemning environmental injustice.

Contamination by oil crude extraction - Refinement and their effects on human health

The harmful effects of oil on various species of flora and fauna have been studied extensively; however, few studies have studied the effects of oil exposure on human health. The objective of this research was to collect information on the acute health effects and serious psychological symptoms of the possible consequences of such exposure to crude oil. Some studies focused on the composition of different chemicals used in the extraction process, and wastes generated proved to be highly harmful to human health. Thus, studies have shown that individuals who live near oil fields or wells - or who take part in activities of cleaning oil spills - have presented health conditions, such as irritation to the skin, eyes, mucous membranes, kidney damage, liver, reproductive, among others. In Ecuador, this reality is not different from other countries, and some studies have shown increased diseases related with oil crude and oil spills, like skin irritation, throat, liver, lung, infertility, and abortions, and it has been linked to childhood leukemia. Other studies suggest a direct relationship between DNA damage because of oil resulting in a genetic instability of the main enzymes of cellular metabolism as well as a relationship with some cancers, such as leukemia.

Levels of 1-hydroxypyrene in urine of people living in an oil producing region of the Andean Amazon (Ecuador and Peru)

PURPOSE

Polycyclic aromatic hydrocarbons (PAHs) are contaminants with carcinogenic effects but little is known about their presence in environments surrounding oil drilling operations and spills or exposure levels in nearby communities. The objective of this study was to characterize PAH levels in people living near oil drilling operations in relation to fish consumption, occupation, source of water and other socio-demographic characteristics.

METHODS

This pilot study examined PAH exposure by measuring 1-hydroxypyrene (1-OHP) in urine samples using high-performance liquid chromatography and fluorescence detection from 75 women and men in the Ecuadorian and Peruvian Amazon living near oil drilling operations and who answered a questionnaire collecting socio-demographic, occupational and dietary information. Data were analyzed using multiple linear regression models.

RESULTS

The mean value of 1-OHP was 0.40 μmol/mol creatinine, 95% CI 0.32-0.46 μmol/mol creatinine. Women who used water from a surface source (for washing clothes or bathing) had almost twice the amount of 1-OHP in their urine (mean 1-OHP = 0.41 μmol/mol creatinine, 95% CI 0.28-0.54 μmol/mol creatinine, n = 23) as women who used water from either a well, a spring or rain (mean 1-OHP = 0.22 μmol/mol creatinine, 95% CI 0.11-0.34 μmol/mol creatinine, n = 6). Men who reported eating a bottom-dwelling species as their most commonly consumed fish (mean 1-OHP = 0.50 μmol/mol creatinine, 95% CI 0.36-0.64 μmol/mol creatinine, n = 31) had twice as much 1-OHP in their urine as men who reported a pelagic fish (mean 1-OHP = 0.25 μmol/mol creatinine, 95% CI 0.15-0.35 μmol/mol creatinine, n = 15), signaling either oral (fish consumption) or dermal (while standing in water fishing benthic species) exposure.

CONCLUSIONS

More contact with surface water and benthic fish may result in higher levels of 1-OHP in human urine among the study population. Reducing the amount of oil and wastes entering the waterways in Andean Amazonia would be one way to reduce exposure.

Breast Cancer Epidemiology in Gulf Cooperation Council Countries: A Regional and International Comparison

Breast cancer is the most frequently diagnosed noncutaneous malignancy in women living in Gulf Cooperation Council countries. The present report aimed to highlight the similarities and variations in breast cancer incidence, age at diagnosis, clinicopathologic features, molecular characteristics, and lifestyle factors that contribute to an increasing incidence of breast cancer compared with neighboring Arab and westernized countries. The data presented, although having important implications for policy makers, also highlights the need for further research. Such research would ensure that effective prevention and detection strategies are tailored to the specific needs of the Gulf women such that the management of breast cancer is optimized.

Unravelling the life history of Amazonian fishes through otolith microchemistry

Amazonian fishes employ diverse migratory strategies, but the details of these behaviours remain poorly studied despite numerous environmental threats and heavy commercial exploitation of many species. Otolith microchemistry offers a practical, cost-effective means of studying fish life history in such a system. This study employed a multi-method, multi-elemental approach to elucidate the migrations of five Amazonian fishes: two 'sedentary' species (Arapaima sp. and Plagioscion squamosissimus), one 'floodplain migrant' (Prochilodus nigricans) and two long-distance migratory catfishes (Brachyplatystoma rousseauxii and B. filamentosum). The Sr : Ca and Zn : Ca patterns in Arapaima were consistent with its previously observed sedentary life history, whereas Sr : Ca and Mn : Ca indicated that Plagioscion may migrate among multiple, chemically distinct environments during different life-history stages. Mn : Ca was found to be potentially useful as a marker for identifying Prochilodus's transition from its nursery habitats into black water. Sr : Ca and Ba : Ca suggested that B. rousseauxii resided in the Amazon estuary for the first 1.5-2 years of life, shown by the simultaneous increase/decrease of otolith Sr : Ca/Ba : Ca, respectively. Our results further suggested that B. filamentosum did not enter the estuary during its life history. These results introduce what should be a productive line of research desperately needed to better understand the migrations of these unique and imperilled fishes.

Health effects of non-occupational exposure to oil extraction

Oil extraction may cause extensive environmental impact that can affect health of populations living in surrounding areas. Large populations are potentially exposed to oil extraction related contamination through residence in areas where oil extraction is conducted, especially in low and middle income countries (LMICs). Health effects among people residentially exposed to upstream oil industry contaminants have been poorly studied. Health effects of exposure to oil related contamination have been mainly studied among cleanup workers after oil spills from tankers or offshore platforms.In this paper we aim to identify the type and extension of residential exposures related to oil extraction activities and to comment on the few health studies available. We estimated that 638 million persons in LMICs inhabit rural areas close to conventional oil reservoirs. It is relevant to specifically study people residentially exposed to upstream oil industry for the following reasons: First, persons are exposed during long periods of time to oil related contamination. Second, routes of exposure differ between workers and people living close to oil fields, who can be exposed by ingestion of contaminated waters/foods and by dermal contact with contaminated water and/or land during daily activities (e.g. bathing, agricultural activities, etc.). Third, individuals potentially more susceptible to the effect of oil related contamination and not normally occupationally exposed, such as infants, children, pregnant women, elderly or people with previous health conditions, are also exposed.There are few papers studying the potential health effects of residential exposure to oil related contamination, and most of them share important limitations. There is a need for more research through the conduct of methodologically robust studies in exposed populations worldwide. Despite the difficulties in the conduct of studies in remote areas, novel approaches, such as measurement of individual exposure using biomarkers of exposure and effect, should be used. These studies should be promoted to understand the health risks associated to residential exposure to oil related contamination, support effective control policies to avoid such contamination and to sustain public health recommendations and policies to avoid exposure in already contaminated areas.

Petroleum contaminated water and health symptoms: a cross-sectional pilot study in a rural Nigerian community

BACKGROUND

The oil-rich Niger Delta suffers from extensive petroleum contamination. A pilot study was conducted in the region of Ogoniland where one community, Ogale, has drinking water wells highly contaminated with a refined oil product. In a 2011 study, the United Nations Environment Programme (UNEP) sampled Ogale drinking water wells and detected numerous petroleum hydrocarbons, including benzene at concentrations as much as 1800 times higher than the USEPA drinking water standard. UNEP recommended immediate provision of clean drinking water, medical surveillance, and a prospective cohort study. Although the Nigerian government has provided emergency drinking water, other UNEP recommendations have not been implemented. We aimed to (i) follow up on UNEP recommendations by investigating health symptoms associated with exposure to contaminated water; and (ii) assess the adequacy and utilization of the government-supplied emergency drinking water.

METHODS

We recruited 200 participants from Ogale and a reference community, Eteo, and administered questionnaires to investigate water use, perceived water safety, and self-reported health symptoms.

RESULTS

Our multivariate regression analyses show statistically significant associations between exposure to Ogale drinking water and self-reported health symptoms consistent with petroleum exposure. Participants in Ogale more frequently reported health symptoms related to neurological effects (OR = 2.8), hematological effects (OR = 3.3), and irritation (OR = 2.7).

CONCLUSIONS

Our results are the first from a community relying on drinking water with such extremely high concentrations of benzene and other hydrocarbons. The ongoing exposure and these pilot study results highlight the need for more refined investigation as recommended by UNEP.

Cancer in indigenous people in Latin America and the Caribbean: a review

Cancer is a leading cause of death in Latin America but there have been few assessments of the cancer burden for the 10% of the population who are indigenous. Evidence from other world regions suggests cancer survival is poorer for indigenous people than for others due to a greater incidence of case-fatal cancers, later stage at diagnosis, and less cancer treatment. A status report on the cancer profile of indigenous people in Latin America and the Caribbean (LAC) is therefore clearly warranted. We undertook a systematic review of the peer-reviewed literature in academic databases, and considered evidence from cancer registries from 1980, to assess cancer epidemiology among indigenous people in LAC. We identified 35 peer-reviewed articles pertaining to cancer in indigenous people. Rates of cervical cancer in parts of Brazil, Ecuador, and Guyana, stomach cancer rates in regions of Chile and gallbladder rates in Chile and Bolivia, were higher for indigenous compared to others. Breast cancer rates were lower in Ecuador, Brazil, and Chile. Six cancer registries in Brazil provided incidence data but no other reports of incidence, mortality, or survival were identified. There was a paucity of data surrounding the cancer burden of indigenous people in LAC. In view of predicted increases in cancer rates in ensuing decades, and the disparities in burden already experienced by indigenous people in the region, it is imperative that cancer profiles are obtained and cancer control measures identified and prioritized.

Anicteric hepatoxicity: a potential health risk of occupational exposures in Nigerian petroleum oil refining and distribution industry

BACKGROUND

Literature abounds linking one's job to certain unpalatable health outcomes. Since exposures to hazardous conditions in industrial environments often results in sundry health effects among workers, we embarked on this study to investigate the hepatic health effects of occupational activities in the petroleum refining and distribution industry.

METHOD

Biochemical markers of liver functions were assayed in plasma, using Reflotron dry chemistry spectrophotometric system. The study was conducted on randomly selected workers of Port Harcourt Refining Company (PHRC) and Pipelines and Petroleum Product Marketing Company (PPMC) both in Alesa-Eleme near Port Harcourt, Nigeria, as well as non-oil work civil servants serving as control subjects.

RESULT AND CONCLUSION

Results showed that, bilirubin ranged 0.3-1.6 mg/dl with a mean of 0.66±0.20mg/dl among the oil workers as against 0.5-1.00mg/dl with a mean of 0.58±0.13mg/dl in non-oil workers, Alkaline phosphatase ranged 50.00-296.00u/l (mean: 126.21±39.49u/l) in oil workers as against 40.20-111u/l (mean: 66.83±18.54u/l) for non-oil workers, Aspartic transaminases (AST) ranged 5.80-140.20u/l (mean: 21.81±11.49u/l) in oil workers against 18.00-44.00u/l (mean: 26.89±6.99u/l) for non-oil workers, while Alanine transaminases (ALT) ranged 4.90-86.00u/l (mean: 22.14±11.28u/l) in oil workers as against 10.00-86.60u/l (mean: 22.30±10.22u/l) for the non-oil workers. A close study of the results revealed that although the mean values for all the studied parameters were still within the parametric reference ranges, however, relative to the referents, there were significant increases (P<0.05) in plasma bilirubin (though anicteric) and alkaline phosphatase that was not matched with a corresponding increase in the plasma transaminases, suggesting a possibility that toxic anicteric hepatoxicity is part of the potential health effects of sundry exposures in the Nigeria petroleum oil refining and distribution industry. Gender differentiation data showed that though the mean values for the parameters were higher in males than females, the increases were not significant in most cases (P>0.05), whereas data for age and exposure period classifications revealed that irrespective of the age of the worker, the effects are likely to start after the first five years, manifesting fully after the first decade of occupational exposures. Thus, an update of industrial/occupational health measures is necessary for a safer and healthier work environment.

Cancer mortality and quantitative oil production in the Amazon region of Ecuador, 1990-2010

Purpose

Controversy persists over whether cancer risk is increased in communities surrounding oil fields, especially in the Oriente region of Ecuador. This ecologic study uses quantitative exposure data, updated mortality data, and improved statistical methods to study the impact of oil exploration and production activities on cancer mortality rates in the Oriente.

Methods

Cancer mortality rates in the Oriente in 1990 through 2010 were compared between seven cantons with active oil exploration and production as of 1990 and thirteen cantons with little or no such activities. Poisson regression was used to estimate mortality rate ratios (RRs) adjusted for age and sex. In a two-stage analysis, canton-specific log-RRs were regressed against quantitative estimates of cumulative barrels of oil produced and well-years per canton, adjusting for canton-level demographic and socioeconomic factors.

Results

Overall and site-specific cancer mortality rates were comparable between oil-producing and non-oil-producing cantons. For overall cancer mortality in males and females combined, the RR comparing oil-producing to non-oil-producing cantons was 0.85 [95 % confidence interval (CI) 0.72–1.00]. For leukemia mortality, the corresponding RR was 0.80 (95 % CI 0.57–1.13). Results also revealed no excess of mortality from acute non-lymphocytic, myeloid, or childhood leukemia. Standardized mortality ratios were consistent with RRs. Canton-specific RRs showed no pattern in relation to oil production volume or well-years.

Conclusions

Results from this first ecologic study to incorporate quantitative measures of oil exploration and production showed no association between the extent of these activities and cancer mortality, including from cancers associated with benzene exposure.

Electronic supplementary material

The online version of this article (doi:10.1007/s10552-013-0308-8) contains supplementary material, which is available to authorized users.

Lymphohematopoietic Malignancies and Oil Exploitation in Koprivnica-Krizevci County, Croatia

To determine lymphohematopoietic malignancy incidence rates between populations living near oil-gas fields (two regions) compared with those living in areas free from oil-gas exploitation (one region) in Koprivnica-Krizevci County, Croatia, 803 new cases of lymphohematopoietic malignancies were studied for two time periods: 1971-1980 (prior to oil-gas exploitation) and 1981-2000 (during oil-gas exploitation). The results showed considerable geographic differences in the incidences of chronic myeloid leukemia and multiple myeloma. The authors conclude that proximity to oil or gas fields represents an increased population risk of developing lymphohematopoietic cancers.

Leukemia in children and youths of the Azuay province, Ecuador: 2000-2010

We mapped leukemia risk among children and youths in the Azuay province, Rio Paute river basin, Ecuador, in 2000-2010, using a Bayesian disease mapping model. We assessed the comprehensiveness of the list of leukemia cases from the Sociedad de Lucha contra el Càncer en el Ecuador (SOLCA) Hospital in Cuenca, the only referral center for oncology in the whole Rio Paute area, by comparison to the Quito cancer registry. Risk of leukemia did not vary significantly by canton within the Azuay province. However, a moderate increase in risk of borderline statistical significance was observed in the city of Cuenca and particularly among males in a heavily industrialized parish, who had an almost eight-fold excess (95% CI 3.03, 20.39, p = 0.01) of AML. Analytical studies are warranted to properly address specific etiological factor of leukemia among children and youths of the Azuay province of Ecuador.

Evaluation of spatial relationships between health and the environment: the rapid inquiry facility

BACKGROUND

The initiation of environmental public health tracking systems in the United States and the United Kingdom provided an opportunity to advance techniques and tools available for spatial epidemiological analysis integrating both health and environmental data.

OBJECTIVE

The Rapid Inquiry Facility (RIF) allows users to calculate adjusted and unadjusted standardized rates and risks. The RIF is embedded in ArcGIS so that further geographical information system (GIS) spatial functionality can be exploited or results can be exported to statistical packages for further tailored analyses where required. The RIF also links directly to several statistical packages and displays the results in the GIS.

METHODS

The value of the RIF is illustrated here with two case studies: risk of leukemia in areas surrounding oil refineries in the State of Utah (USA) and an analysis of the geographical variation of risk of esophageal cancer in relation to zinc cadmium sulfide exposure in Norwich (United Kingdom).

RESULTS

The risk analysis study in Utah did not suggest any evidence of increased relative risk of leukemia, multiple myeloma, or Hodgkin's lymphoma in the populations around the five oil-refining facilities but did reveal an excess risk of non-Hodgkin's lymphoma that might warrant further investigation. The disease-mapping study in Norwich did not reveal any areas with higher relative risks of esophageal cancer common to both males and females, suggesting that a common geographically determined exposure was unlikely to be influencing cancer risk in the area.

CONCLUSION

The RIF offers a tool that allows epidemiologists to quickly carry out ecological environmental epidemiological analysis such as risk assessment or disease mapping.

Morbidity and mortality disparities among colonist and indigenous populations in the Ecuadorian Amazon

Rural populations living in the northern Ecuadorian Amazon (NEA) experience the highest health burden of any region in the country. Two independent studies of colonist and indigenous groups living in the NEA are used to compare their morbidity and mortality experiences. Colonist data are from a probability sample of land plots in 1999, while indigenous data are from a representative sample of the five largest ethnicities (Quichua, Shuar, Huaorani, Cofan, Secoya) collected in 2001. Poisson regression was used to compare morbidity. Results indicate clear differences in health between populations. Indigenous groups had 30% higher probability of mortality and 63% higher incidence rate of all-cause morbidity compared to colonists. Vector-borne, chronic, gastrointestinal, and diseases of unknown origin were particularly high among indigenous groups. Factors associated with morbidity varied: morbidity rates were similar for the two youngest age groups (0-4 and 5-9), but indigenous people aged 15-39 and 40+ had almost double the morbidity compared to colonists; larger households, later months of data collection and less pollution were associated with less morbidity in both groups; better infrastructure access (electricity and roads) was generally associated with lower morbidity in both groups; and associations of land use were different by group with more cultivation of perennials and fewer annuals associated with less morbidity for colonists, but more for indigenous groups. These results demonstrate the health disparities that exist among indigenous and non-indigenous populations even when living in the same geographic region. Land use itself exemplifies the cultural and contextual differences that are evident in health, since land use decisions are related to broader demographic and economic factors that influence overall ecological and human health. Ongoing population-environment and/or environment-health research needs to recognize the broader factors involved when studying relationships between population health, development and deforestation.

Cancer mortality and oil production in the Amazon Region of Ecuador, 1990-2005

OBJECTIVES

To compare cancer mortality rates in Amazon cantons (counties) with and without long-term oil exploration and extraction activities.

METHODS

Mortality (1990 through 2005) and population census (1990 and 2001) data for cantons in the provinces of the northern Amazon Region (Napo, Orellana, Sucumbios, and Pastaza), as well as the province with the capital city of Quito (Pichincha province) were obtained from the National Statistical Office of Ecuador, Instituto Nacional del Estadistica y Censos (INEC). Age- and sex-adjusted mortality rate ratios (RR) and 95% confidence intervals (CI) were estimated to evaluate total and cause-specific mortality in the study regions.

RESULTS

Among Amazon cantons with long-term oil extraction, activities there was no evidence of increased rates of death from all causes (RR = 0.98; 95% CI = 0.95-1.01) or from overall cancer (RR = 0.82; 95% CI = 0.73-0.92), and relative risk estimates were also lower for most individual site-specific cancer deaths. Mortality rates in the Amazon provinces overall were significantly lower than those observed in Pichincha for all causes (RR = 0.82; 95% CI = 0.81-0.83), overall cancer (RR = 0.46; 95% CI = 0.43-0.49), and for all site-specific cancers.

CONCLUSIONS

In regions with incomplete cancer registration, mortality data are one of the few sources of information for epidemiologic assessments. However, epidemiologic assessments in this region of Ecuador are limited by underreporting, exposure and disease misclassification, and study design limitations. Recognizing these limitations, our analyses of national mortality data of the Amazon Region in Ecuador does not provide evidence for an excess cancer risk in regions of the Amazon with long-term oil production. These findings were not consistent or supportive of earlier studies in this region that suggested increased cancer risks.

Oil development and health in the Amazon basin of Ecuador: the popular epidemiology process

Recent decades have witnessed an increasing corporate access to and control over natural resources resulting in environmental degradation, inequalities and ill health. Since 1972, oil companies have extracted more than two billion barrels of crude oil from the Ecuadorian Amazon. During this process, millions of gallons of untreated toxic wastes, gas and oil have been released into the environment. Indigenous federations, peasant's movements and environmental groups have claimed that contamination has caused widespread damage to both people and the environment. This article tells the story of how the relationship between local organisations and research institutions developed around an epidemiological study constructed to address communities' concerns. Local organisations set the agenda of the research: they were involved in the hypothesis formulation, consulted in each step during the study and responsible of the dissemination of the findings. This process is known as popular epidemiology. Practical and personal issues and dilemmas faced during the research process are discussed with emphasis on the communication and dissemination of the findings. The article concludes the need of alliances between communities and researchers in order to protect health and environment. Popular epidemiology is an essential approach for public health researchers to reaffirm their roots in improving public health as a primary value.

Incidence of childhood leukemia and oil exploitation in the Amazon basin of Ecuador

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.

Geographical differences in cancer incidence in the Amazon basin of Ecuador in relation to residence near oil fields

BACKGROUND

Since 1972, oil companies have extracted more than 2 billion barrels of crude oil from the Ecuadorian Amazon, releasing billions of gallons of untreated wastes and oil directly into the environment. This study aimed to determine if there was any difference in overall and specific cancer incidence rates between populations living in proximity to oil fields and those who live in areas free from oil exploitation.

METHODS

Cancer cases from the provinces of Sucumbios, Orellana, Napo and Pastaza during the period 1985-1998 were included in the study. The exposed population was defined as those living in a county (n = 4) where oil exploitation had been ongoing for a minimum of 20 years up to the date of the study. Non-exposed counties were identified as those (n = 11) without oil development activities. Relative risks (RR) along with 95% CI were calculated for men and women as ratios of the age-adjusted incidence rates in the exposed versus non-exposed group.

RESULTS

The RR of all cancer sites combined was significantly elevated in both men and women in exposed counties. Significantly elevated RR were observed for cancers of the stomach, rectum, skin melanoma, soft tissue and kidney in men and for cancers of the cervix and lymph nodes in women. An increase in haematopoietic cancers was also observed in the population under 10 years in the exposed counties in both males and females.

CONCLUSION

Study results are compatible with a relationship between cancer incidence and living in proximity to oil fields. An environmental monitoring and cancer surveillance system in the area is recommended.