Assessment on the pollution and potential ecological risk of persistent toxic substances in the surface sediments at Maowei National Marine Park

The spatial distribution and integrative pollution effect of persistent toxic substances were discussed and evaluated based on the investigation heavy metals (Cu, Pb, Zn, Cd, Hg, As) and DDTs、PCBs in 13 surficial sediment samples collected from the Maowei National Marine Park, Guangxi.The results showed that the average concentration of heavy metals (×10^-6, dry wt) followed the sequence of Zn (56.9) > Pb (19.0) > Cu (12.6) > As (10.7) > Cd (0.14) > Hg (0.075), and the average concentration of DDTs、PCBs were 1.08 and 0.70(×10^-9, dry wt), respectively.All the pollution factors calculated were lower than the first class regulated by the GB 18668-2002.The order of potential ecological risks followed by Cd > Hg > As > Cu > Pb > Zn and the average potential ecological risk was 98.39, indicated a low potential ecological risk from the Maowei National Marine Park.The high value of northeastern Maowei National Marine Park was mainly due to the high potential risk of Cd.The concentrations of DDTs and PCBs of all point were lower than ERL, indicated that Maowei sea had a low potential ecological risk.