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Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)e- thane (DDD), hexachlorocyclohexane (HCH) and its isomers (α-,β-, γ-, and δ-HCH), hexachlorobenzene (HCB), endo- sulfan, dieldrin, and endrin were quantified to determine current levels of organochlorine pesticides, to assess the eco- toxicological potential, and to distinguish previous and current inputs in agricultural soils from the Taihu Lake region. Gas chromatography equipped with a 63Ni electron-capture detector (GC-ECD) system was employed. Thirteen OCPs were detectable in all soil samples, with DDTs being the main residues, and HCHs had the second highest level of OCP residues. Although OCP residual levels were lower than those in 1990s, the residual levels for most of the DDTs and some of HCHs were still higher than the national environmental standards for agricultural soils. The ratios of DDT/DDE and γ-/α-HCH in twelve soils indicated that new inputs could be present in the soils. Thus, efforts should be made to completely ban the production of OCPs and their use in agriculture so as to reduce the threat of OCPs to food quality and human health.
Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT) and its principal metabolites 1,1-dichloro-2,2- (DDE) and 1,1-dichloro-2,2-bis (p-chlorophenyl) e-thane (DDD), hexachlorocyclohexane (HCH) and its isomers (α-, β-, γ-, and δ-HCH ), hexachlorobenzene (HCB), endo- sulfan, dieldrin, and endrin were quantified to determine the eco-toxicological potential, and to distinguish between current inputs in agricultural soils from the Taihu Lake region. Gas Chromatography equipped with a 63Ni electron-capture detector (GC-ECD) system was employed. Thirteen OCPs were detectable in all soil samples, with DDTs being the main residues, and HCHs had the second highest level of OCP residues. lower than those in 1990s, the residual levels for most of the DDTs and some of HCHs were still higher than the national environm ental standards for agricultural soils. The ratios of DDT / DDE and γ- / α-HCH in twelve soils indicate that new inputs could be present in the soils. Thus, efforts should be made to completely ban the production of OCPs and their use in so so to reduce the threat of OCPs to food quality and human health.