The Influence of Changes in Lifestyle and Mercury Exposure in Riverine Populations of the Madeira River (Amazon Basin) near a Hydroelectric Project

Abstract

In the Amazon Basin, naturally occurring methylmercury bioaccumulates in fish, which is a key source of protein consumed by riverine populations. The hydroelectric power-plant project at Santo Antônio Falls allows us to compare the Hg exposure of riverine populations sparsely distributed on both sides of the Madeira river before the area is to be flooded. From 2009 to 2011, we concluded a population survey of the area (N = 2,008; representing circa 80% of community residents) that estimated fish consumption and mercury exposure of riverine populations with different degrees of lifestyle related to fish consumption. Fish samples from the Madeira river (N = 1,615) and 110 species were analyzed for Hg. Hair-Hg was significantly lower (p < 0.001) in less isolated communities near to the capital of Porto Velho (median 2.32 ppm) than in subsistence communities in the Cuniã Lake, 180 km from Porto Velho city (median 6.3 ppm). Fish Hg concentrations ranged from 0.01 to 6.06 µg/g, depending on fish size and feeding behavior. Currently available fish in the Madeira river show a wide variability in Hg concentrations. Despite cultural similarities, riparians showed hair-Hg distribution patterns that reflect changes in fish-eating habits driven by subsistence characteristics.

Child Nutritional Status in the Changing Socioeconomic Region of the Northern Amazon, Brazil

“…In addition to air pollution, children living in North Brazil, where rapid urbanization, poor housing, and lack of sanitation coupled with intensive mining and agricultural projects (compromising natural resources and traditional living) are occurring are predisposed to a greater probability of exposure to pollution and chemical contamination [ 4 , 5 ]. In the northern region, 10,415,597 people (approximately 32% of the total population in Brazil) are estimated to live in areas contaminated or suspected of being contaminated [ 16 ] with mining wastes (toxic metals) and industrial and urban residues [ 32 ].…”

“…For example, in the northern region, the national development policy for road construction, colonization projects, and hydroelectric dams has contributed to economic growth, infrastructure, and socio-demographic changes. This policy has resulted in a direct impact on the environment [ 4 , 5 ] and, consequently, on human health by leading to changes in living conditions and the incidence of endemic infectious and parasitic diseases [ 4 ]. The northern region encompasses 45% of the territory of Brazil.…”

Human Mercury Exposure in Yanomami Indigenous Villages from the Brazilian Amazon

“…In the Brazilian Amazon, mercury contamination due to ASGM has been reported since the early 1980s. High levels of mercury have been shown by several authors, mainly in riparian populations in that region [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Despite being recognized as particularly susceptible populations, there are few studies of Hg exposure in indigenous Amazonian communities.…”

Inquérito de saúde em comunidades ribeirinhas do Amazonas, Brasil

“…Adicionalmente, o clima tropical e a floresta com dimensões colossais, atrelados à proximidade do homem com tal ambiente, constituem um fator singular para o desenvolvimento de agravos de saúde típicos da Região Amazônica. Investigações prévias apontam que fatores como baixa escolaridade, condição econômica insuficiente 7,8 , ausência de saneamento básico 7,9,10 , aliadas ao rol de doenças infecciosas endêmicas da região 11,12 , parecem ter associação importante no perfil epidemiológico dessa população.…”