Mercury in Predatory and Non-Predatory Fish in the Madeira River, Brazilian Amazon RegionAbstract
Madeira River (Rondônia State, Brazil) is known to be contaminated with mercury (Hg), which can be biomagnified and bioaccumulated through the food chain. The situation raises concern given there are riverside inhabitants that consume fish. Therefore, 18 fish species with a broad spectrum of eating habits were investigated. Mercury concentrations in fish muscle were evaluated according to the limits established by the Brazilian National Health Surveillance Agency (ANVISA) and the European Union (EU). ANVISA sets maximum limits of 1.0 µg g-1 for predator species and 0.5 µg g-1 for non-predator species (Brazil), whereas EU establishes a maximum limit of 0.5 µg g-1 (EU). Thirteen species have Hg levels above the maximum recommended (ANVISA limits). The Hg concentration ranged from 0.15 to 20.7 and 0.012 to 1.14 µg g-1 for predatory and non predatory fish, respectively. A flow batch chemical vapor generation-inductively coupled plasma mass spectrometric (CV-ICP-MS) method was used, with limit of detection (LOD) of 0.012 µg g-1, value below the maximum limit for mercury in fish established by ANVISA and the European Union. Accuracy was evaluated by analyzing certified refence material (CRM), with precision better than 5% (relative standard deviation, n = 5). The results demonstrate the current status of Hg in fish and highlight the seriousness of environmental contamination, as mercury concentrations in several species exceed expected levels. In addition, Hg levels in fish muscle are comparable to or higher than those reported in studies conducted in the same region since 2000.
Keywords:
mercury; fish; mercury bioaccumulation; risk assessment