Oil activities impacts on tropical rainforest ecosystems and human populations have been scarcely evaluated, although about 30% of the world tropical rainforests overlap with hydrocarbon reservoirs. This PhD thesis aims to shed light on one of the unstudied potential impacts of oil activities in tropical rainforests: the ingestion of oil-polluted soils and water by Amazonian wildlife. Indigenous populations living in a remote oil extraction area in the Peruvian Amazon originally reported the ingestion of oil-polluted soils and water by Amazonian wildlife. In 2013, a two-week camera trap pilot study was conducted to investigate this claim. Videos clearly showed four species ingesting oil-polluted soil and water, illustrating an animal behaviour unknown to the scientific community and raising questions about the environmental and public health implications of this behaviour. In this context, the overarching goals of this thesis were 1) to study this potential new route of exposure to oil-related pollutants for wildlife and 2) to determine whether wild species consumed by local populations living in the vicinity of oil extraction areas was polluted by lead (Pb), a pollutant related to the oil extraction industry. Over the course of four years, a myriad of methodologies from diverse disciplines (i. e. , ethology, conservation biology, environmental chemistry, environmental forensics, but also spatial analysis, community-based monitoring, and citizen science) have been used framed in the field of environmental sciences. The participation of local people has been crucial to develop this research, including developing the research questions, designing the methodology, collecting and analysing data, and interpreting results. Two main results derive from this dissertation. First, the ingestion of oil-polluted soil and water by wildlife is a frequent widespread behaviour, both in taxonomical and geographical terms. The extent of the behaviour might be explained by the fact that animals are, indeed, redirecting geophagy from natural salt licks to oil-polluted sites. Second, liver tissues from wild and free-ranging Amazonian species presented high Pb concentrations, comparable to those found in wildlife in industrial countries and mining areas. Lead-based ammunition and oil pollution are identified as the main sources of Pb pollution. These findings suggest that mainly lead-based ammunition, but also, oil extraction activities may pose an environmental and health risk to wild species and local human populations that rely on subsistence hunting for their livelihoods. These results suggest that, similarly to oil-related Pb, other toxic and cumulative compounds related with oil extraction might also be entering the food chain and threatening wildlife and human populations, but more research on this topic is needed. Given these findings, this thesis argue for the need to increase research on oil extraction impacts in tropical rainforests. The results also highlight that the phase-out of lead-based ammunition around the world is urgently needed. Finally, governmental institutions and oil companies are invited to promptly and efficiently review the operational standards and remediation practices of oil companies operating in tropical areas.