Distribution And Source Identification On The Persistent Organic Pollutants In The Surface Sediments From Qingdao Coastal Areas

Due to their persistence, bioaccumulation, toxicity and long-term transference, the persistent organic pollutants (POPs) have become a hot-spot and received wide attention from the international society. In this study, we investigated two categories of the POPs: the 16 USEPA priority controlled polycyclic aromatic hydrocarbons (PAHs) and the organochlorinated compounds, including 13 Polychlorinated biphenyls (PCBs) and 17 organochlorinated pesticides (OCPs) from 17 surface sediments from Qingdao coastal areas by using GC-MS. In addition, since the serious pollution status of petroleum in the coastal areas, we also kept an eye on the n-alkanes investigation from 15 surface sediments. The study shows:(1) The 16 USEPA priority controlled PAHs were detected in all of the sediments and the total PAHs concentration ranges from 220.6 - 2150.8 ng/g dw,. The distribution pattern of the mean PAHs is: the stations in the Jiaozhou Bay > the stations along the northeastern coast > the stations along the southwestern coast. Both the sources index of the PAHs (∑LPAHs/∑HPAHs, Phen/Ant) and the principal component analysis (PCA) reveals that the PAHs in the study area come from the petrogenic and pyrolytic sources. Compared with the PAHs concentration from other area and based on the Sediment Quality Guidelines (SQGs) advanced by Long, the PAHs pollution in Qingdao coastal areas is relatively low and the study area belongs to the low ecological-risk district.(2) The total concentrations of PCBs and OCPs from Qingdao coastal areas are 1.51-43.72 ng/g dw and 1.96-20.01ng/g dw., respectively. The distribution pattern of the mean PCBs and OCPs is: the stations along the southwestern coast > the stations in the Jiaozhou Bay > the stations along the northeastern coast. The predominant pollutants detected are low-chlorinated PCBs (3-5 Cl) in PCBs and β-HCH and p, p'-DDE in OCPs. The PCBs detected from the stations in the Jiaozhou Bay and near the Huangdao Industry District are come from the discharge of the industrial petroleum and sewage, while the PCBs from other stations come from the atmospheric deposition. The PCBs pollution in the study area is relatively low and would not pose any adverse effect on the organisms. For the OCPs, 15 OCPs are detected in the sediments except the heptachlor and its epoxide. The ratio ofα-HCH/γ-HCH is high, indicating that there is no fresh use of lindane in this area. The ratio of (DDD+DDE)/DDTs is relatively high, showing that the there is no fresh input of DDTs and the sedimentary environment is relatively aerobic. The OCPs pollution is also relatively low compared with other area, while the DDTs may pose some adverse effect on the organisms in the definite area.(3) The total concentrations of n-alkanes in Qingdao coastal areas ranges from 700.1 -10094.9 ng/g dw (the carbon number ranges from 11-33), and the distribution pattern of the mean n-alkanes is: the stations along the southwestern coast > the stations along the northeastern coast > the stations in the Jiaozhou Bay. The sources index of the alkanes and PCA show that the alkanes primary come from the petroleum pollution.As a summary, this study poses a relatively systemic investigation on two organic pollutants (PAHs, OCs and n-alkanes) in the surface sediments from Qingdao coastal areas. The results could provide the base for the environmental pollution prevention and cure in the definite area.