Comparative study of mercury speciation in commercial fishes of the Brazilian Amazon

Abstract

Mercury is responsible for serious episodes of environmental pollution throughout the world, especially in the Amazon. This toxicity has led regulatory agencies to focus on fish as the target organism for protecting the health of humans and other sensitive organisms. Unfortunately, in the Amazon area, different sampling strategies and the wide variety of sampling areas and fish species make it extremely difficult to determine relationships across geographic regions or over time to ascertain historical trends. Thus, the aim of this work was to achieve three main objectives: a comparative study of mercury contamination in fish of Itaituba (Tapajós, located downstream of the largest gold-mining region in Amazon) and Belém (an area non-exposed to mercury pollution of anthropogenic origin), perform an analysis of inorganic mercury (IHg) versus monomethylmercury (MeHg) contents, and, finally, compare mercury contamination in Tapajós over time. Five piscivorous species were obtained in Itaituba and Belém. Also, four non-piscivorous species were collected in Itaituba. For the first time, mercury speciation showed that (1) current MeHg levels in piscivorous species in Tapajós are higher than those of the non-exposed area, (2) piscivorous species from Itaituba (dourada, filhote, and sarda) contained mercury levels above the World Health Organization safety limit (~17%) and/or above the US Environmental Protection Agency tissue residue criterion (40%), (3) increased MeHg is usually accompanied by increased IHg, and (4) the mean total mercury concentrations for piscivorous species in Itaituba were within the same range and, associated uncertainties as those previously reported, although a remarkable decreasing trend over time was observed for mean total Hg concentrations in non-piscivorous species from Itaituba. The present study supports the importance of continuous monitoring of both populations in the Amazon Rivers. Our results will better assist the development of preventive strategies and governmental actions to confront the problem of mercury contamination in the Amazon.

In the Heart of the Amazon: Noncommunicable Diseases and Apolipoprotein E4 Genotype in the Riverine Population

“…One of the largest dams in the world is located in Tucuruí ( Figure 1 ), and human exposure to high levels of mercury was recently demonstrated in riverine population in this area [ 34 ]. Mercury is bioaccumulated and biomagnified through the food chain and by piscivorous fish, which are the species that are typically consumed the most by riverine population [ 52 , 53 ]. These fish show the highest levels of contamination [ 52 , 53 ].…”

Oxidative Biochemistry Disbalance and Changes on Proteomic Profile in Salivary Glands of Rats Induced by Chronic Exposure to Methylmercury

“…The anthropogenic action leads to higher concentrations on biosphere and may expose animals of aquatic food chain to damage [ 5 ]. Many researches have reported that fishes and other seafood are the main sources of human contamination by low daily doses, in which about 90% of Hg is present on its organic form, leading to higher bioaccumulation and biomagnification [ 6 , 7 ].…”

Mercury Contamination within Protected Areas in the Brazilian Northern Amazon-Amapa State

“…Mercury contamination is a long-standing environmental and social problem throughout the world, especially in the Amazon (Martín-Doimeadios et al, 2014;Berzas Nevado et al, 2010). The widespread use of mercury (Hg) in artisanal and small-scale gold mining has driven contamination of the environment and people, threatening biodiversity, human health and livelihoods of traditional population.…”

“…Nevertheless, these studies suggest large-scale environmental disruption, with widespread contamination, affecting biodiversity Kehrig et al, 2008;Dolbec et al, 2001;Bidone et al, 1997;Porvari, 1995) and impacting health of local communities that relies on fish as a protein source (Martín-Doimeadios et al, 2014;De Oliveira Santos et al, 2000), including indigenous people (Barbosa et al, 1998;Basta et al, 2016).…”