Distribution And Sources Of Persistent Organic Pollutants In Surface Sediments From Bohai Bay

Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and poly chlorinated biphenyls (PCBs) are the first group of Persistent Organic Pollutions (POPs) to be controlled as specified in the Stockholm Convention on POPs. Once presented at the environmental media, they, due to POPs possess toxic properties, resist degradation, bioaccumulate and are transported and deposited far from their places of release, where they accumulate in ecosystems for long periods, are becoming a great threat to human beings' subsistence, propagation and sustainable development.To determine the compositional characteristics and potential sources of the PAHs, OCPs, and PCBs in surface sediments of Bohai Bay, the sediments samples were collected from Haihe River Estuary and extending to the middle of the Bohai Sea and then analyzed using the GC/MS apparatus.First of all, The total concentration of PAHs in this studying areas ranged from 213.25 to 608.98 ng g-1 dry weight, with a mean value of 398.94 ng g-1. Compared with decade years ago in these study areas, there were one order of magnitude higher increasing in total PAHs concentration and were well around the midpoint of the China PAHs concentration range. Following the sampling locations, the concentrations of the different compounds were shifted diversely, the low molecular weight PAHs such as naphthalene accounted for the individual sampling stations, 38% of the total concentration of PAHs. Compositional pattern analysis and principal component analysis were employed to evaluate the potential sources, the combustion source was dominant and the petroleum source also should be attention. But there is not a single pollutant sources in individual or several stations showing an absolute dominant. Through the ecological risk assessment, the low ecological risk in this areas could be concluded.In addition, total OCP concentration in surface sediment ranged from 9.01 to 18.04 ng g-1 dry weight, with a mean concentration of 12.50 ng g-1. These findings are in the mid-range of pesticide concentrations compared to those reported in other regions worldwide. DDTs and HCHs were the predominant species. Theα-HCH/β-HCH ratios and the predominantγ-HCH indicate that the technical HCH contamination was due mainly to historical usage, although there appeared to be a fresh input of lindane. The results from (DDD+DDE)/∑DDTs and DDD/DDE calculations suggest that the usage of DDT in agricultural activities was not terminated.Finally, the range of total concentration of PCBs in this areas were 4.02 73.37ng g-1, with a mean concentration 29.01 ng g-1. Compared with the other regions, this rank stands at a relatively low concentration range. It might be close to the environment background value with PCBs.