Composition, distribution, and characterization of suspected endocrine-disrupting pesticides in Beijing GuanTing Reservoir (GTR)

GuanTing Reservoir (GTR) is one of two main water resources for the agriculture, industry, and living uses of Beijing (China). As a result of extensive pollution over the last few decades (particularly the 1980s), the reservoir has not supplied potable water to Beijing city since 1997. Composition, distribution, and characterization of 31 suspected endocrine-disrupting pesticides in surface water, pore water, and surface sediments from the reservoir are reported in this study. An analytical procedure based on solid-phase extraction (SPE) technology and capillary gas chromatography with electron-capture detection has been developed for the simultaneous determination of the 31 suspected endocrine-disrupting pesticides including the compounds hexachlorocyclohexane, cyclodiene, diphenyl aliphatic, chlordane, and other selected pesticides (hexachlorobenzene, heptachlor, endrin aldehyde, hepachlor epoxide, dicofol, acetochlor, alachlor, metolachlor, chlorpyriphos, nitrofen, trifluralin, cypermethrin, fenvalerate, and deltamethrin). The result shows that the pesticide pollution is moderate in GTR and its tributaries, although pesticide residue values in a few sites are quite high when considering their endocrine-disrupting effects and chronic health effects. Among the analyzed pesticides, p,p'-DDE, o,p'-DDT, beta-HCH, endosulfan sulfate, and aldrin were the most abundant pesticides in water while o,p'-DOT, delta-HCH, beta-HCH, p,p'-DDE, p,p'-DDT, and endosulfan sulfate were the most abundant in sediment. The variation in concentration of pesticides among sites can be expected to be caused by several factors such as contaminants in the rivers and drainage of contaminated water from the surrounding agricultural fields. To reduce exposure to these endocrine-disrupting compounds, the abundant current use of pesticides in the area should be minimized. Regular monitoring is needed to manage the environmental hazards due to these pesticides.