Contaminação por mercúrio e os impactos na saúde: o cenário da notificação no Brasil e análises teórica e prática na Amazônia

Abstract

The Amazon is a relevant case for studying the environmental and health impacts caused by mercury. Activities such as mining, deforestation, and large-scale development projects intensify the mobilization of this metal, posing challenges for public health surveillance—especially in areas where mercury exposure is chronic. Studies indicate that the accumulation of this metal in the body is associated with cardiovascular and neurological diseases, putting vulnerable populations at risk. This study analyzed the relationship between mercury contamination and public health in the Amazon. The specific objectives were: i) to explore notifications of human exposure/intoxication cases related to mercury; ii) to conduct a theoretical review of current knowledge on mercury contamination in the Amazon region; and iii) to carry out a cross-sectional epidemiological study in riverside communities of the Amazon, assessing cardiovascular risk through lipid and genetic profilesFor the study on epidemiological surveillance, data from the Notifiable Diseases Information System (SINAN) on exogenous intoxication were obtained online, covering the years 2007 to 2022. Two researchers independently analyzed and selected the cases using a standardized protocol. After extracting the relevant data from each record, analyses were conducted on the geographic distribution of cases, age, pregnancy status, and identification of specific codes. For the review, a comprehensive literature search was conducted, including scientific articles, reports, and relevant studies. This narrative review enabled both qualitative and quantitative analysis of the findings, focusing on key outcomes and implications for public health and the environment in the region. Finally, to assess the association between mercury and cardiovascular risk, anthropometric data were collected from participants. Lipid profiles and levels of apolipoproteins B (ApoB) and A-I (ApoA-I) were measured by spectrophotometry. Total mercury and methylmercury (MeHg) levels in hair samples were quantified using ICP- MS and GC-pyro-AFS. The polymorphisms rs662799, rs693, rs429358, and rs7412 (in apolipoprotein genes A-V, B, and E at positions 112 and 158, respectively) were genotyped by real-time PCR. SINAN recorded only 668 suspected/confirmed cases of mercury exposure over 16 years, with just 15.6% occurring in the Brazilian Amazon, highlighting severe underreporting in this region. The review showed that the mercury biogeochemical cycle in the Amazon is highly dynamic, influenced by mining, deforestation, and large-scale development projects, which contribute to widespread mercury mobilization and dissemination throughout the region. As a result, local populations showed exposure concentrations 2 to 6 times higher than reference doses. Additionally, the studied riverside population presented a dyslipidemia profile significantly correlated with mercury levels in hair. The ApoB/ApoA-I ratio was also positively correlated with mercury, supporting a possible causal relationship. Allelic distributions were similar to those described in other populations. Conclusions: Despite the availability of tools such as SINAN and the work of Community Health Agents, official data fail to reflect the actual exposure experienced by these populations. Underreporting of mercury exposure compromises the understanding of the true magnitude of the problem and hinders the implementation of effective public policies. This scenario particularly affects the Amazon region. The mercury cycle in the Amazon is unique and extremely complex, shaped by both natural features and human activities. Moreover, Amazonian populations exhibit higher exposure levels than other regions of the world. The analysis of a riverside population demonstrated for the first time: i) the association between mercury exposure and apolipoproteins related to cardiovascular risk in humans, ii) ApoB levels and the ApoB/ApoA-I ratio as the risk factors most strongly associated with mercury-related dyslipidemia in humans, and iii) the prevalence of high/moderate risk of acute myocardial infarction in this population, along with the genotypic profile of the three most frequent polymorphisms in apolipoproteins relevant to cardiovascular risk.