title: Level and distribution of DDT in surface soils from Tianjin, China.
abstract: One hundred and eighty eight surface soil samples were collected from the Tianjin area to study the contamination of DDT and its metabolites. Measurements were taken for p,p'-DDE, p,p'-DDD, p,p'-DDT, o,p'-DDE, o,p'-DDD and o,p'-DDT for all samples. The results indicated that p,p'-DDT and p,p'-DDE were the predominant contaminant compounds in the surface soil samples, with mean concentrations of 27.5 and 18.8 ng g(-1) respectively. No significant differences in DDT concentrations were found between the soils from wastewater treated irrigated areas and other areas, suggesting that wastewater irrigation is not an important source of DDT in the area. However, the spatial distribution of soil DDTs levels in the area did correlate well with early direct application rates of pesticides. In addition, both pH level and organic carbon content are also known factors affecting the level of DDT and its metabolites. Although it was assumed that the use of these chemicals was banned in the early 1980s, the current concentration levels appear to be too high to be mere residuals after 20 years degradation.
authors.affiliation: Department of Urban and Environmental Sciences, MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China.
authors.forename: Z M
authors.initials: ZM
authors.lastname: Gong
authors.forename: S
authors.initials: S
authors.lastname: Tao
authors.forename: F L
authors.initials: FL
authors.lastname: Xu
authors.forename: R
authors.initials: R
authors.lastname: Dawson
authors.forename: W X
authors.initials: WX
authors.lastname: Liu
authors.forename: Y H
authors.initials: YH
authors.lastname: Cui
authors.forename: J
authors.initials: J
authors.lastname: Cao
authors.forename: X J
authors.initials: XJ
authors.lastname: Wang
authors.forename: W R
authors.initials: WR
authors.lastname: Shen
authors.forename: W J
authors.initials: WJ
authors.lastname: Zhang
authors.forename: B P
authors.initials: BP
authors.lastname: Qing
authors.forename: R
authors.initials: R
authors.lastname: Sun
mesh_terms: D000383:Agriculture / Q000379:methods; D000704:Analysis of Variance; D002244:Carbon / Q000032:analysis; D002681:China; D002849:Chromatography, Gas; D003634:DDT / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D004784:Environmental Monitoring; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted / Q000379:methods; D010573:Pesticide Residues / Q000032:analysis; D012680:Sensitivity and Specificity; D012989:Soil Pollutants / Q000032:analysis*; D014881:Water Supply
chemical_list: D010573:Pesticide Residues; D012989:Soil Pollutants; D002244:Carbon; D003634:DDT