Methylmercury in Fish from the Amazon Region-a Review Focused on Eating Habits

Fish are an important food and economic source in the Amazon region. However, several researches report high levels of mercury, mainly methylmercury (MeHg), in these animals. MeHg is capable of biomagnifying in the ecosystem and negatively affect human health. Amazon region is recognized for its great diversity of fish species and high daily consumption of fish, extremely vulnerable to the toxic effects of MeHg. Therefore, this study aimed to carried out a systematic review on MeHg in Amazon fishes by their eating habits and estimate the human exposure of MeHg by fish consumption. The search was carried out according to registered search protocol in the electronic databases PubMed/Medline and Web of Science. After screening selection, only five studies were included in this review. Carnivore/piscivore fishes showed the highest concentrations of MeHg (0.51 +/- 0.37 mg kg(-1)), followed by planktivores/iliophages (0.45 +/- 0.32 mg kg(-1)). Herbivore fish have the lowest MeHg concentration (0.11 +/- 0.09 mg kg(-1)). Both indexes (estimated weekly intake-EWI and provisional tolerable weekly intake-PTWI) were higher among women. EWI/PTWI ratio was higher than 1 for all eating habits, suggesting a risk to MeHg associated with the consumption of fish in the region, with higher rates in carnivorous/piscivorous fish, which may cause serious health problems to Amazon population. Thus, it is necessary to establish public politics to minimize exposure to MeHg in this region and to guarantee food and nutritional security.

Automated summary

This study conducted a systematic review on MeHg levels in Amazon fishes by their eating habits, finding that carnivore/piscivore fishes had the highest MeHg concentrations, while herbivore fish had the lowest. Women had higher estimated weekly intake (EWI) and provisional tolerable weekly intake (PTWI) indexes. Consuming fish in the region poses a MeHg risk, especially in carnivorous/piscivorous fish, which may lead to serious health issues for the Amazon population.