Fish diet and mercury exposure in a riparian Amazonian population

Bioaccumulation and Biomagnification of Mercury through Food Webs

“…Similarly, Morrissey et al (2010) demonstrated that during egg laying, females of the dipper species Cinclus mexicanus consumed a more piscivorous diet, which resulted in a transfer of Hg to eggs; this was evident from the δ 15 N signature in eggs, where those with higher δ 15 N had higher total Hg concentrations. Correlations between diet shifts and Hg concentrations have also been documented in people who become vegetarians (Srikumar et al, 1992), and in areas where human diet is particularly dependent on seasonal food availability (Lebel et al, 1997;Donkor et al, 2006).…”

Neurotoxic Sequelae of Mercury Exposure: An Intervention and Follow-up Study in the Brazilian Amazon

“…In this form, it then becomes bioavailable to the ichthyofauna, where it can be biomagnified through every step of the food web up to humans (WHO 1989). The high level predators present the highest concentrations of Hg (Lebel et al 1997;Sampaio da Silva et al 2009), reflected in the biomarkers of exposure in humans (Passos and Mergler 2008).…”

Temporal Evolution of Exposure to Mercury in Riverside Communities in the Tapajós Basin, from 1994 to 2010

“…Blood mercury concentration, particularly blood organic mercury concentration, reflects the frequency and amount of consumed fish as well as the mercury concentration in fish (Mahaffey and Mergle 1998). Although our purpose in the present study does not include the analysis of the amount of ingested fish, there are studies showing that riverside communities along the Tapajós river basin have a high ingestion of fish in the food (Lebel et al 1997;Passos and Mergler 2008). In a study conducted in communities near São Luiz do Tapajós, it was observed that the population feeds mainly highly mercury contaminated piscivorous and omnivorous species during the raining season, while their diet was based in herbivorous fish species during the dry season (Lebel et al 1997).…”

“…Although São Luiz do Tapajós is nearer from gold-mining areas than Barreiras, the levels of mercury exposure across time are similar in both communities, suggesting that similar features such as preference and frequency of ingestion of piscivorous fish species and lacking of nutritional antioxidant compounds (fruits and nuts) would have influenced the exposure scenario. For instance, it has previously been shown that the consumption of fruits obtained in the region where these communities are located, has favorable effects to reduce the mercury levels in head hair samples (Lebel et al 1997).…”

“…Recent studies performed in this region have demonstrated high mercury concentration in muscle tissue and viscera from some consumed fish species (Vieira et al 2011). Although the occupational exposure to mercury vapor has been reported in the Amazon, the main concern is still what happens through feeding (Lebel et al 1997).…”