title: Effects of different treatments on soil-borne DDT and HCH dynamics and plant uptake.
abstract: Pot experiments were conducted to examine the effects of various fertilizers, as well as soil dilution treatments on the dynamics of soil-borne DDTs [sum of dichlorodiphenyltrichloroethane (DDT), chlorodiphenyldichloroethylene (DDE) and di- chlorodiphenyldichloroethane (DDD)] and hexachlorocyclohexanes (HCHs, sum of α-HCH, β-HCH, γ-HCH and δ-HCH) and their subsequent impacts on the uptake of DDTs and HCHs by a test plant. The results show that the soil residual DDTs and HCHs concentrations in the iron-rich fertilizer-treated soil were significantly lower than those in other fertilizer-treated soils. There was a close relationship between the soil residual DDTs and the plant tissue DDTs. This suggests that the uptake rate of DDTs by the plant was dependent on the concentration of soil-borne DDTs. A less close relationship between soil residual HCHs and plant tissue HCHs was also observed. Dilution of pesticide-contaminated soil with the non-contaminated soil not only physically reduced the concentration of pesticides in the soil but also enhanced the loss of soil-borne pesticides, possibly through the improvement of soil conditions for microbial degradation. Soil dilution had a better effect on promoting the loss of soil-borne HCHs, relative to soil-borne-DDTs. The research findings obtained from this study have implications for management of heavily contaminated soils with DDTs and HCHs. Remediation of DDTs and HCHs-contaminated soils in a cost-effective way can be achieved by incorporating treatment techniques into conventional agricultural practices. Applications of iron-rich fertilizer and soil dilution treatments could cost-effectively reduce soil-borne DDTs and HCHs, and subsequently the uptake of these organochlorine pesticides by vegetables.
authors.affiliation: Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou, China.
authors.forename: Huashou
authors.initials: H
authors.lastname: Li
authors.forename: Weifeng
authors.initials: W
authors.lastname: Ling
authors.forename: Chuxia
authors.initials: C
authors.lastname: Lin
mesh_terms: D003634:DDT / Q000032:analysis* / Q000378:metabolism; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005308:Fertilizers / Q000032:analysis; D001556:Hexachlorocyclohexane / Q000032:analysis* / Q000378:metabolism; D010575:Pesticides; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism; D014675:Vegetables / Q000737:chemistry / Q000378:metabolism*
chemical_list: D005308:Fertilizers; D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; D001556:Hexachlorocyclohexane; D003634:DDT