Garimpagem e contaminação ambiental por mercúrio na Amazônia: uma abordagem a partir dos povoados Cipoeiro e Chega-Tudo em Centro Novo do Maranhão

Abstract

Gold mining in the Amazon is one of the most environmentally degrading economic activities, particularly due to the use of mercury (Hg) as an amalgamating agent, a highly toxic and persistent substance. In the municipality of Centro Novo do Maranhão, located in the Maranhão Amazon, this practice remains an alternative livelihood, especially in the villages of Chega Tudo and Cipoeiro, where artisanal gold mining occurs illegally, without environmental and health controls. This context raises concerns about the contamination of sediments, water, and aquatic organisms, with direct repercussions on human health and food security. The objective of this research was to analyze the levels of mercury contamination in sediments, water, and fish in areas affected by gold mining in Centro Novo do Maranhão, identifying the environmental and social impacts resulting from gold mining and their implications for local communities. The methodology adopted was based on a geosystemic and dialectical approach, integrating the natural and social dimensions of the landscape. Interviews were conducted with 49 residents of villages adjacent to the mining operations, and eight sediment samples, eight water samples, and one fish sample (Pseudoplatystoma corruscans) were collected during two seasonal periods (high and low seasons). The results showed mercury levels in river waters ranging from 0.012 to 0.6 µg·L⁻¹, indicating contamination levels ranging from 10% to 200%. Sediment contamination levels ranged from 0.016 to 19 mg·Kg⁻¹, representing contamination levels between 1382% and 3808% when compared to the limits established by Brazilian environmental legislation. Analysis of the interviews revealed that 51% of residents had worked in mining, 67% recognized mining as their main source of income, and 74% associated it with health risks and river contamination. The data demonstrate the coexistence of economic dependence and socio-environmental vulnerability, reflecting the lack of effective public policies to control and mitigate the impacts of illegal mining. The results reinforce the urgent need to develop environmental education, economic diversification, and effective oversight initiatives capable of reducing the exposure of mining workers to mercury and promoting sustainable alternatives for the Amazonian population.