Biogeochemistry Of Organochlorine Pollutants In Hongfeng Reservoir

In this research, seven PCB congeners and thirteen organochlorine pesticides in all environment media including air, soil, water, sediment, fish from Hongfeng Reservoir area were determined, and their distribution and composition were analyzed. Correlation between physico-chemical properties (i.e. TOC, grain size, SPM and microbial) and this POPS were also discussed. In this paper, we investigated the source of PCBs and OCPs in the Hongfeng Reservoir and assessed contaminant level of PCBs and OCPs. Following is the detailed results we obtained:1. The contents of TOC and C/N atomic ratios of sediment in the Hongfeng Reservoir and the Erhai Lake indicated that the sources of organic matters in Hongfeng Reservoir are from both tributaries and lacustrine hydrophytes, while the sources of organic matters in Erhai Lake are mainly from lacustrine hydrophytes. The profiles of organic matters and DNA show the similar decreasing trend from surface to bottom, suggesting higher quantity and activity of microbe in the surface sediment. SRI and SRB reveal that microbe play an important role in degradation of organic matters.2. The concentrations of total PCBs range from 3.2 to 31.6 ng/g in sediments in the Hongfeng Reservoir. PCB28, PCB52 are the major congeners with the concentrations range between 0.5 to 4.6ng/g, and 0.4 to 28.1ng/g, respectively. The composition of PCBs in all samples is consistent and the differences of contents are due to the input and environmental factors. The concentrations of these pollutants decrease on the whole profiles, while the concentration at 1～4cm is lower than 5～8cm, suggesting the decline of PCBs input. Grain size and TOC of sediment are found significant positive correlation to PCBs, indicating that PCBs are adsorbed to organic matters and particles more easily.3. HCHs and DDTs are the predominant organochlorine pesticides with the concentrations range from 1.6 to 8.9ng/g (average 3.2ng/g) and 0.9 to 25.7ng/g (average 7.8ng/g), respectively. β-HCH and γ-HCH (lindane) are the predominant HCH isomers from sediments, and p,p'-DDE and p,p'-DDT are the predominant DDT...