Mercury levels in feed and muscle of farmed tilapia.

Background Fish consumption is considered the most important source of contaminant exposure for humans beings, and farmed fish can be exposed to contaminants via feed supply. Methods Total mercury concentrations (THg) were determined in the muscle, liver, and feed of farmed Nile tilapia (juveniles and adults) from four different fish farms in Brazil (net cages and intensive tanks systems), by a flow injection mercury system. Results Mercury concentrations observed in fish muscle were markedly lower (13.530.5?mu g?kg-1) than the values recommended by ANVISA/MAPA for edible part of fish (500?mu g?kg-1), and in the liver the concentrations found were higher than in the muscle. Conclusions These low levels of THg in farmed tilapia may be due to the low THg concentrations found in the analyzed fish feed, that ranged from 5.2 to 33.2?mu g?kg-1, below the limit of 100?mu g?kg-1 established by the European Commission