Mercury Exposure in the Bolivian Amazon Basin: Comparison With the General Amazonian Situation

Abstract

ISEE-153 Objective: Methylmercury exposure in riverside communities through fish consumption and its risk to human health are sources of concern, and have been extensively studied in Brazilian Amazonia. Even though Brazilian and Bolivian Amazonian populations share similar environment and alimentary habits, there is an evident lack of data on mercury exposure outside Brazil. Thus, this study aimed to assess mercury exposure in the general population of a lower Beni River community (Cachuela Esperanza: 10° 32′ S 65° 35′ W). In addition, we reviewed published data on other Amazonian studies, looking forward to envision the Amazon basin general situation. Material and Methods: We used simple random sampling from the whole population, by performing a survey by private interview and taking hair samples to measure total mercury concentrations. These and the reviewed studies' results were sorted by hydrographic basin and target group and then represented on thematic Amazon basin maps. Results: Hair mercury levels in Cachuela Esperanza (geometric mean: 3.02 μg/g) were lower than those found in Brazilian studies. Nevertheless, this confirmed that the population was exposed. In comparison, the Madeira River basin showed hair mercury means ranging from 8 to 16 μg/g, whereas the Tapajós River basin showed hair mercury means ranging from 5 to 64 μg/g. Although there is a strong difference between basins, the spatial distribution of exposure levels does not display a clear pattern. Conclusions: The mercury exposure situation in Amazonia is very heterogenic. Besides, although certain Amazon populations were repeatedly studied, others remain without information on this problem. Thus, it would be necessary to assess mercury exposure in Amazonian regions still lacking in data, using a standardized indicator for the general population.