Abstract

Dichlorodiphenyltrichloroethanes (DDTs) are persistent organic: pollutants that were widely, used in. China, especially eastern China, as insecticides. This work investigated the concentration, dissipation, and volatilization of DDTs and enantiomeric fractions (EFs) of o,p'-DDD and o,p'-DDT in agricultural soils collected in 2006 from 58 sites in Zhejiang province. Correlations between DDT residues and soil properties were assessed to determine the effect of soil properties. on the environmental attenuation of DDTs. High concentrations and detection frequencies were found for DDTs in agricultural soils in the region even though large-scale use of DDTs was banned over 20 years, ago. The amount of DDTs Was about 485 tons in the upper 20 cm of the soil column of cropland in the province in 2010, with a dissipation half-life of similar to 9 years. The mass flux of DDTs was 43 ng m(-2) h(-1), which corresponds to emissions of 7.6 tons with in emission factor of 1.6% in 2006. The low p,p'-DDT/p,p'-DDE: ratios and high o,p'-DDT/p,p'-DDT ratios suggest. that there were no recent inputs of DDTs but fresh application of dicofol, which contains DDT (o,p'-DDT in particular) impurities.. The significant positive correlation between concentrations of DDTs and total organic carbon content (TOC) indicates the distribution of DDTs fit a typical "secondary distribution" pattern. DEVrac of o,p'-DDD, which is defined as the absolute value Of EFs subtracted from 0.5, was significantly related with most of the physicochemical and microbial soil properties. The most significant correlation is that between DEVrac of o,p'-DDD and soil pH (p < 0.001), indicating that the soil pH plays' a key role in enantioselective residues. of DDTs.

Keywords

soil; DDTs; dissipation; volatilization; enantiomeric fraction

Published in

Journal of Agricultural and Food Chemistry
2012, Volume: 60, number: 34, pages: 8294-8301
Publisher: AMER CHEMICAL SOC

UKÄ Subject classification

Analytical Chemistry
Organic Chemistry
Environmental Sciences


Publication identifier

DOI: https://doi.org/10.1021/jf3024547

Permanent link to this page (URI)

https://res.slu.se/id/publ/53651