Environmental Contamination of Fish and Humans through Deforestation and Oil Extraction in Andean Amazonia

This dissertation assesses the levels of mercury in fish and human populations and PAHs in local communities along three rivers in the Ecuadorian and Peruvian Amazon. Land use changes in the Amazon are begetting numerous negative impacts on both ecosystems and local populations. One negative consequence of deforestation is the contamination of local ecosystems by mercury (Hg), a potent neurotoxic agent, which is leached from soils when river-side plots are cleared. In the Andean Amazon, the incursion of petroleum companies has led to road construction, colonization and areas of intense deforestation. The techniques used in the extraction of oil in this remote and overlooked region have left a legacy of contamination, specifically heavy metals such as Hg and polycyclic aromatic hydrocarbons (PAHs). Limited research has evaluated the degree of Hg contamination in the Andean Amazon and less research still has determined the state of contamination as a result of oil extraction. The purpose of this research is to uncover the extent of contamination in fisheries and human populations reliant on the fish and water resources of the area.;Hg levels in some predatory fish species exceed World Health Organization (WHO) recommendations (range = 0.001-2.97 mug/g). Fish from a heavily contaminated micro watershed were found to have bioaccumulated more Hg. Hair-Hg levels in humans (range = 1.07-24.78 mug/g) were found to be significantly related to number of fish meals consumed per week. Hg levels in urine (range = 0.02-15.62 mug/g creatinine) were dependant on source of washing water for women and work cleaning up an oil spill for men. Concentrations of urinary 1-OHP (range = 0.03-1.62 mumol/mol creatinine) were likewise related to source of washing water in women; but, in men, the most significant variable was bottom-dwelling fish species as most commonly eaten fish. The one health outcome examined in this dissertation showed that the number of miscarriages a woman reported was significantly associated with higher levels of 1-OHP. Results were communicated to the community members through a theatrical play. The play was intended to provide information that would help people reduce their exposure to contaminants while maximizing nutritional intake from fish. The play was narrated by the research team and community members were incorporated as actors.;The primary conclusions drawn from these findings are that petroleum extraction is leading to increased levels of Hg in fish and humans and increased concentrations of PAHs in local people. At least one negative health outcome of exposure to PAHs---miscarriages---has been shown to be associated with higher levels of contaminants in the bodies of women. Theatre was found to be a successful method for engaging participants, eliciting comments and questions and fostering a genuine interaction with the community.;Eight communities along three white water rivers---the Napo River (Ecuador), the Corrientes River (Peru) and the Pastaza River (Peru)---with differing degrees of deforestation and oil extraction were studied. Questionnaires were administered to 192 people who accepted to provide hair samples. Samples of commonly eaten fish were collected. A subsample of the study population (n=76) also provided a urine sample. Biological samples of fish (n=486), human hair and urine were analysed for Hg and samples of urine were analysed for 1-hydroxypyrene (1-OHP), a metabolite of one of the most common PAHs. Regression analysis was used to draw links between contamination levels and socio-demographic, dietary and occupational characteristics of the population. One health outcome---miscarriages---was evaluated in the questionnaires and examined in light of contamination levels.