Organotropism of methylmercury in fish of the southeastern of Brazil

Effects of illegal gold mining on Hg concentrations in water, Pistia stratiotes, suspended particulate matter, and bottom sediments of two impacted rivers (Paraíba do Sul River and Muriaé River), Southeastern, Brazil

“…In the MR, there were also reports of an increase in garimpo activities since July 2021 (Folha de Italva, 2021b ; Jornal Terceira Via, 2021 ). Previous studies conducted in this drainage basin indicated high Hg concentrations in several fish species, especially demersal ones (up to 0.3 µg∙g −1 ), indicating the significant role of garimpo activities concerning Hg biota exposure (Azevedo et al, 2017 , 2018 ; Rocha et al, 2015 ).…”

“…Since both rivers present forests adjacent to their banks, organic matter most likely plays an important role increasing Hg affinity to the SPM (Figueiredo et al, 2011 ). Furthermore, reports of high Hg concentrations in the gills of detritivorous fish species in the RPS basin were attributed to the direct contact of these species with the sediment, indicating the significant role of this compartment in Hg biota exposure (Azevedo et al, 2017 ), especially during the dry season (Azevedo et al, 2018 ). Based on the maximum Hg concentrations detected among species with different feeding habits in the region (0.3 µg∙g −1 wet weight; Azevedo et al, 2017 ) for which the safe ingestion limit established by the WHO should be exceeded (4 µg∙kg −1 per week per body weight; WHO, 2008 ), an average person (70 kg body weight) would need to eat between 1.0 and 1.5 kg of fish per week.…”

“…Furthermore, reports of high Hg concentrations in the gills of detritivorous fish species in the RPS basin were attributed to the direct contact of these species with the sediment, indicating the significant role of this compartment in Hg biota exposure (Azevedo et al, 2017 ), especially during the dry season (Azevedo et al, 2018 ). Based on the maximum Hg concentrations detected among species with different feeding habits in the region (0.3 µg∙g −1 wet weight; Azevedo et al, 2017 ) for which the safe ingestion limit established by the WHO should be exceeded (4 µg∙kg −1 per week per body weight; WHO, 2008 ), an average person (70 kg body weight) would need to eat between 1.0 and 1.5 kg of fish per week. Fish consumption in Southeastern Brazil does not exceed 43 g per week (IBGE, 2010 ), so no major Hg-related health problems are expected for the population around the study areas.…”

Mercúrio em peixes comercializados em Minas Gerais e possíveis riscos associados ao seu consumo

“…Além da biomagnificação, o mercúrio é bioacumulado nos organismos vivos e vários fatores podem influenciar esses fenômenos, como idade, ambiente e as fontes alimentares. (Azevedo et al, 2017, Soares et al, 2018, Cao et al, 2019. , Terrázas-López et al, 2019 Em 2018, a Comissão do Development, v. 9, n. 9, e105996881, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i9.6881 Codex Alimentarius (FAO/WHO, 2019) estabeleceu limite máximo para metilmercúrio em cação de 1,6 mg/kg.…”

“…A forma orgânica é a mais abundante em pescado e mais absorvida após ingestão (cerca de 95%) (FAO/WHO, 2011, EFSA, 2012, Cao et al, 2019. Development, v. 9, n. 9, e105996881, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i9.6881 Após ser ingerido, o MeHg passa pelos processos de bioacumulação, variando com idade, ambiente e fonte da alimentação, dentre outros fatores, e biomagnificação, que resulta no seu acúmulo em organismos vivos, ocasionando um aumento na sua concentração conforme aumenta o nível da cadeia alimentar (Azevedo et al, 2017, Soares et al, 2018, Cao et al, 2019, Silva & Lima, 2020, Yoshino et al 2020. O MeHg possui afinidade por hemácias e células do tecido nervoso, atravessando facilmente a barreira hematoencefálica e também a barreira placentária, se acumulando no feto e podendo causar toxicidade (Caserta et al, 2013, Ekino et al, 2007, Myers et al, 2015.…”