The residues, distribution, and partition of organochlorine pesticides in the water, suspended solids, and sediments from a large Chinese lake (Lake Chaohu) during the high water level period.

The levels of organochlorine pesticides (OCPs) in the water, suspended solids, and sediments from Lake Chaohu during the high water level period were measured by a solid-phase extraction gas chromatograph-electron capture detector. The spatial distributions of the three phases and the water/suspended solids and sediment/water partition coefficients were analyzed. The results showed the following: (1) The mean contents of OCPs in the water, suspended solids, and sediments were 132.4 ± 432.1 ng/L, 188.1 ± 286.7 ng/g dry weight (dw), and 13.7 ± 9.8 ng/g dw, respectively. The dominant OCP components were isodrin (85.1%) for the water, DDTs (64.4%) for the suspended solids, and both isodrin (48.5%) and DDTs (31.8%) for the sediments. (2) β-HCH was the primary isomer of HCHs in the water and sediments, and the proportions were 61.7 and 41.3%; γ-HCH was the primary isomer in the suspended solids, accounting for 49.3%; p,p'-DDT was the dominant content of DDTs in the water and suspended solids, whereas p,p'-DDD was the main metabolite of DDTs in the sediments. (3) The concentrations of contaminants in the water from the western lake were greater than those from the eastern lake, but the concentrations in the suspended solids from the western lake were less than those from the eastern lake. (4) There was no significant correlation between the water-suspended solids partition coefficient Kd and the n-octanol-water partition coefficient Kow, and between the sediment-water organic-C weighted sorption coefficients Koc and Kow.