Avaliação da contaminação mercurial mediante análise do teor de Hg total em amostras de cabelo em comunidades ribeirinhas do Tapajós, Pará, Brasil

Abstract

This study evaluates human exposure to methylmercury in fishermen and their families in four villages on the Tapajós river: Rainha, Barreiras, São Luís do Tapajós and Paraná-Mirim. Hair analyses were performed with atomic absorption spectophotometry. Total hair mercury levels varied between 2.9mg/g and 71.5mg/g. Paraná-Mirim showed the lowest level. The highest level was found in São Luís do Tapajós and Barreiras. The hair mercury was six to seven times higher than the established safe limit of 10mg/g. No statistically significant difference was found between the mean level of total mercury taken from the inhabitants living downstream and upstream in Itaituba village (p > 0.05). These results confirm that human exposure to methylmercury is occurring on the Tapajós river and suggest that continued fish ingestion in that region is a potential risk factor for the appearance of symptoms and signs of Minamata disease. An immediate epidemiological survey program is recommended.

Manifestações emocionais e motoras de ribeirinhos expostos ao mercúrio na Amazônia

“…Pinheiro et al 23 , assessing the frequency of neurological signs and symptoms in the riverside-dwelling population in the Tapajós River Basin, observed variations of mercury levels ranging from 0.87 to 44.59 µg/g. Concentration averages higher than those found in this study have already been reported by other authors [3][4][5][6]26,33 , but in periods when mineral prospecting was intense and the preventive educational activities were gaining strength. High Hg levels may be connected to the population's amount and type of fish consumption and to the lack of variation in their diet.…”

“…The Hg levels in hair samples is considered the best bioindicator of exposure to Hg from ingestion of contaminated food 17 and is commonly used by several authors 5,[7][8][9][10][11]23,29 to measure long-term exposure. Through the different hydrographic locations it is possible to identify Hg exposure variations in each region.…”

“…In these studies, the Hg levels in Itaituba were significantly higher (p < 0.0001) than those in Acará. The riverside-dwelling communities in the Tapajós region have a history of long-term exposure, for approximately two decades, and are known for uncontrolled mineral exploration [5][6][7][8]26 . Riverside dwellers in Acará had low HgT levels, which can be explained by the location, which is far from mineral prospecting, and by fish consumption with low HgT levels.…”

“…The case provided an important body of information on the clinical symptoms and epidemiological characteristics of mercury poisoning, serving as a milestone for the mobilization of organized segments of civil society in different parts of the world, including Brazil 2 . In the Amazon region, several studies monitor the levels of mercury exposure in the population [3][4][5][6][7][8][9][10][11] and the fish [12][13][14] , as the region presents a consequent contamination resulting from mineral prospecting, forest fires, the presence of large natural reservoirs and the implantation of hydroelectric plants that cause flooding, transferring mercury from the soil to the water column 15 . Mercury (Hg) as a fish contaminant is a form of non-occupational exposure; its concentration occurs in the organic form of methylmercury (MeHg).…”

Efeito da sazonalidade na exposição ao mercúrio e nos marcadores do estresse oxidativo e de inflamação em populações ribeirinhas da Amazônia

“…Independente das dinâmicas sociais e ambientais do Hg na região do presente estudo, uma vertente é unidirecional -a da elevada exposição humana ao metal (DOLBEC et al, 2001;DÓREA et al, 2005aDÓREA et al, , 2005bGUIMARÃES et al, 1998;LEBEL et al, 1997;PINHEIRO et al, 2000PINHEIRO et al, , 2006.…”