The Environmental Behavior Of Typical Organic Pollutants In Soils And Sediments From The Yellow River Delta,China

In the present research work, a total of 46 soil samples,21 surface sediment samples and a sediment core were collected from the Yellow River Delta Natural Reserve, Yellow River Estuary and the Old Yellow River Estuary, respectively. Based on the environmental analysis methods such as Soxhlet extraction, microwave assisted solvent extraction, sonication extraction, gas chromatography-mass spectrometry analysis and isotope dating, and data analysis methods such as isomer ratios, correlation analysis, factor analysis and hierarchical cluster analysis, the occurrence, distribution, sources and potential risk of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the Yellow River Delta were studied.The major findings of the present research work were as follows:(1) PAHs, PCBs and PBDEs were widespread in the present study area, but their concentrations were relatively low when compared with other locations in the world; In addition, the temporal trend of PAHs in the sediment core effectively archived the anthropogenic activities in the region and the historical economic development in China. (2) The total organic carbon (TOC) content may be not always the factor affecting the distribution of organic pollutants in the Yellow River Delta:PAHs had a significant positive correlation with the TOC contents, but poor correlation was observed between the TOC contents and PCBs or PBDEs. (3) Mixed sources of petroleum, coal, biomass, natural gas and traffic emission primarily contributed to the PAHs in the Yellow River Delta; PCBs and PBDEs may be mainly originated from the long range atmospheric transportation, the manufacture and use of the commercial PCB and PBDE products in the past and the debromination of highly brominated PBDE compounds. (4) Although the concentrations of the four dibenzopyrenes only represented a very small proportion of the total PAH concentrations and the potential of PCBs and PBDEs in the Yellow River Delta as a secondary contamination source was estimated to be very low, the four dibenzopyrenes were found to be the major carcinogenic PAH contributors, PCB 126 and PCB 169 were the major toxicity contributors of dioxin like PCBs, and PentaBDEs such as BDE 99 may be the major ecological risk pusher to the aquatic organisms in the Yellow River Estuary. (5) No correlation was observed among PAHs, PCBs or PBDEs in the Yellow River Estuary, but moderate correlation was observed between PCBs and PBDEs in the Yellow River Delta Natural Reserve, indicating the similar pathways in the long distance atmospheric transportation process of the two organic pollutants.