Assessment of heavy metal pollution in the farmed fish

Contents of Cu, Pb, Cd, Cr, As and Hg in fish muscles collected from two standardized farms for blunt snout bream (Megalobrama amblycephala) and crucian carp (Carassius auratus) culturing in suburb of Shanghai were analyzed.A comprehensive evaluation analysis was made on the pollution of heavy metal in aquatic products using single item pollution exponent method and comprehensive pollution exponent method.The enrichment situation was also compared with different metals.The result showed that contents of Cu, Pb, Cd, Cr and Hg in muscles of blunt snout bream and crucian carp were within the ranges of the“Safety qualification for agricultural product-Safety requirements for non-environmental pollution aquatic products”, the content of As was also within the limits of the“Maximum levels of contaminants in foods”, which indicated these aquatic products were not polluted by Cu, Pb, Cd, Cr, As and Hg, and all belonged to the clean level.Both blunt snout bream and crucian carp have strong enrichment capacity on Cu, Pb, Cd, Cr, As and Hg.The enrichment factor of blunt snout bream on Cu, Pb, Cd, Cr, As and Hg were 459, 14, 17, 263, 1 and 24 respectively, while of crucian carp were 755, 3, 8, 185, 6 and 23 respectively.In these two types of fish, the enrichment ability of Cu was the strongest, followed by Cr.The blunt snout breams were stronger than the crucian carps in enrichment ability on Pb, Cd, Cr and Hg, but weaker on Cu and As.