Distribution Of Heavy Metals And Dietary Exposure Assessment In Freshwater Fishes, Water And Sediments

The presence of heavy metal pollution in aquatic products has raised more and more public health concern. By inductively coupled plasma mass spectrometry with microwave digestion techniques, the heavy metal (Pb, Cd, Cr and As) concentrations were measured in the pond water, sediment and the various tissues (muscle, gill and liver) of crucian carp (Carassius auratus), common carp (Cyprinus carpio) and channa argus (Channidae) collected from three areas in Changxing, Zhejiang, China. The dietary exposure to heavy metals due to freshwater fish consumption was calculated using simple point assessment model, distribution point assessment model and probabilistic assessment model. The hazard quotients (HQs) and hazard index (HI) were calculated to evaluate the non-carcinogenic health risk from individual and combined heavy metals. The main research results are as follows:(1) The average levels of these heavy metals in water samples decreased in the order of As> Cr> Cd、Pb. The concentrations of all examined elements in water samples were below the limits set by the standards.(2) The average levels of these heavy metals in sediments decreased in the order of Cd> As> Pb. Cr. The concentrations of examined elements in sediments, except for Cd in sediments from pond in old industry park (0.381±0.139mg/kg), were below the limits set by the standards.(3) The average levels of these heavy metals in fish muscle decreased in the order of As> Pb> Cd、 Cr. The concentrations of examined elements in fish muscle, except for As in channa argus from the pond in new industry park (0.8974±0.1628mg/kg), were below the limits set by the standards. Generally, the highest concentration of the examined heavy metals in the three fish species was found in the gill or liver tissues.(4) A negative relationship was observed between fish size and heavy metal levels in most cases. A significant correlation was observed for the concentration of metal pairs Pb-Cr, Pb-As. There were significant correlations between concentrations of the heavy metals in the organs of crucian carp and channa argus. (5) The risk assessment indicated that consumption of these three freshwater fish species might not pose a public health risk of Pb, Cd and Cr. However, about13.9%of the local population faced potential non-carcinogenic health risk of As, and about14.2%of the local population faced potential non-carcinogenic health risk of the four combined heavy metals.