Distribution And Ecological Risk Assessment Of Organic Pollutants In Part Of The Yangtze Estuary

The Yangtse estuary, which is the biggest estuary in China occupies an important position in the international estuary and the coast field. However, in recent years, organic pollution in the Yangtze estuary area has become more and more serious question which has been influenced by the natural factors and human activities. In this article the Yangtze estuary area (29°50'～32°00'N, 121°50'～123°00'E) were selected as the study region and the semi-volatile organic compounds (SVOCs) in waters and surface sediment from the Yangtze estuary in April, 2007 were analyzed. The characters of their spatial distribution and their impact factors were also discussed. According to the related standards and the assessment models, the pollution status and risk assessment of this area were stated. To analyze the SVOCs in a sediment core from the Yangtze estuary in April, 2006, the origins and historical change of organic pollutants were discussed. The results showed that:1. The main SVOCs in waters of part of Yangtze estuary contained polycyclic aromatic hydrocarbons (PAHs), esters, phenols, arene derivatives, halohydrocarbons, ethers. The concentrations of the SVOCs in waters of part of Yangtze estuary in the study were affected by the outlets sewage. The concentration of SVOCs was obviously higher than other areas, and demonstrated obvious spatial distribution.Technical Guidance Document (TGD) on the risk assessment of chemicals by European Union was adopted in this paper to assess the ecological risks of SVOCs in waters of part of the Yangtze estuary. It demonstrated that single pollutants except anthracene and di-n-butylphthalate in the selected area did not cause potential damage to the Yangtze River estuary ecosystem.2. The main SVOCs in the surface sediments part of Yangtze estuary contained PAHs, esters, phenols, arene derivatives and halohydrocarbons. The pollution situation had direct relation with sediment grain size, organic pollutants emitted from the cities of the Yangtze River estuary and ship wreck.The ecological risks of PAHs in sediments part of Yangtze estuary showed that phenanthrene had ecological risk. The side effect of naphthalene, fluorene and fluoranthene occurred occasionally while others not.3. The PAHs distribution of the sediment core from the Yangtze estuary could be divided into three stages which well reflected the economic changes of the surrounding area. The origins of PAHs in the sediment core were thermogenic gas before the year 2000, while the combustion sources and the petrogenic sources dominated in recent years.