Zinc and copper bioaccumulation in fi sh from Laizhou Bay, the Bohai Sea

Zinc(Zn) and copper(Cu) concentrations were determined in the tissues(muscle, stomach, liver, gills, skin, and gonads) of fi ve commercial fi sh species(mullet Liza haematocheilus, fl athead Platycephalus indicus, mackerel Scomberomorus niphonius, silver pomfret Pampus argenteus, and sea bass Lateolabrax japonicus) from Laizhou Bay in the Bohai Sea. Metal bioaccumulation was highest in the metabolically active tissues of the gonads and liver. Bioconcentration factors for Zn were higher in all tissues(gonads 44.35, stomach 7.73, gills 7.72, liver 5.61, skin 4.88, and muscle 1.63) than the corresponding values for Cu(gonads 3.50, stomach 3.00, gills 1.60, liver 5.43, skin 1.50, and muscle 0.93). Mackerel tissues accumulated metal to higher concentrations than did other fi sh species, but bioaccumulation levels were not signifi cantly correlated with the trophic levels of the fi sh. Zn and Cu concentrations in the tissues were generally negatively correlated with fi sh length, except for a few tissues of sea bass. Risk assessment based on national and international permissible limits and provisional tolerances for weekly intake of Zn and Cu revealed that the concentrations of these two metals in muscle were relatively low and would not pose hazards to human health.