Risk Assessment On Heavy Metal Pollution Of River Sediments And Crucian Carp (Carassius Auratus Gibelio) In The Haihe River Basin

With the rapid development of urbanization and industrialization, the heavy metal pollution is an attention-getting environmental problem in rivers. The river sediment is a major sink for contaminants discharged into water bodies. Sediment heavy metals can affect aquatic organisms and subsequently enter the food chain, raising the possibility of human health threat. In the Haihe Basin,25 sediments and crucian carps were sampled in 2013 and 2014. Heavy metals in the sediments were measured including Cu, Zn, Pb, Cd, Cr, and As. Based on the results of heavy metal concentration in sediments and different parts of crucian carps, the pollution levels and risk of heavy metals were calculated in some rivers of Haihe River Basin. The main results and conclusions are:(1) Statistical characteristics of sediments heavy metal contents. The average concentration of heavy metals were mostly larger than the background values of the Haihe Basin. The pollution risk decreased in the order of Cd(2.74)>Pb(1.68)>Cu(1.55)>As(1.34)>Zn(1.31)>Cr(1.05). Based on the potential ecological risk index, the heavy metals showed a slight potential ecological risk at most sampling sites except Cd and As. The decreasing ecological risk order of the heavy metals is Cd>As>Pb>Cu>Cr>Zn. The average composite ecological risk of heavy metals in research area was 115.88 closing to the’medium’level.(2) Liver and gill were the target organs for heavy metal accumulation in crucian carps. The results showed that accumulations of heavy metals in the muscle of crucian carps were above standards of National Limited Quantity of Poisonous and Harmful Contents of the National Pollution-Free Aquatic Products (NY5073-2006), Limited Quantity of Contaminants in Foods (GB2762-2012) and Tolerance Limit of Zinc in Foods (GB13106-1991),respectively Pb(2.23)>As(1.31)>Zn(1.28)>Cd(0.79)>Cu(0.11) >Cr(0.10).Food risk was assessed based on the target hazard quotient (THQ) proposed by USEPA. Based on THQ analysis, the TTHQ values in 24% research areas of combined heavy metals were more than 1 and might have risk for the consumption. As and Pb occupied higher proportion in the total risk of fish consumption.(3) According to correlation analysis, heavy metals in sediment showed significant positive correlation with the heavy metal concentration in crucian carps. The accumulation and enrichment of heavy metals in crucian carps were affected by many kinds of biological and non-biological factors. Based on Bio-Sediment Accumulation Factor (BASF) analysis, Zn and Cd had stronger accumulation effects in the livers of crucian carps.The research indicated that the metals of Cd, As, Pb, and Zn had highest pollution risks in the Haihe River Basin.