Study On The Speciation Distribution Of Organochlorine Pesticides In Different Types Of Soils

Organochlorine pesticides pollution is considered as an urgent risk toenvironment and public health on a globle scale, and its contamination in soils is evenserious. In light of the present research method, two types of soils were sampled,respectively from the sandy soil and the clayey soil, to study their organochlorinepesticides contamination. Various combinations of solvents were adopted forsequential extraction of organochlorine pesticides, and GC-QQQ-MS/MS wasemployed for the quantitative determination. The speciation distribution and itsinfluencing factors were discussed, and the main conclusions were drawn as follows.（1）A novel analysis method of organochlorine employing GC-QQQ-MS/MSwas established. It has the superiority of low detection limit, high sensitivity, goodlinear correlation, and acute qualitative and quantitative determination. And the resultsmet the standard of analysis of organochlorine pesticides in soil samples.（2）The soil sampling, preparation, mixing and storing was established. Themechanical compositions of the two soil samples were analyzed, and one soil is sandy,and the other is clayey.（3）The study on the speciation distribution of organochlorine pesticides in thesandy soil indicated that, HCHs and DDTs were primarily in the absorbed andresidual fraction rather than dissolvable and combined fraction. The speciationdistribution of HCHs and DDTs as well as the correlation between octanol-waterpartition coefficient and solubility were also discussed.（4）The study on the speciation distribution of organochlorine pesticides in theclayey soil indicated that, HCHs and DDTs were primarily in the absorbed fractionrather than dissolvable, residual and combined fraction. The species distribution ofHCHs and DDTs as well as the correlation between octanol-water partition coefficientand solubility were also discussed.（5）Various factors including organics, minerals, moisture content, cationexchange capacity, and acidity, were measured to study their influences on thespeciation distribution of organochlorine pesticides in different types of soils. The study shows that the absorbed fraction of organochlorine pesticides is highlycorrelated with the organic content and particle size; The combined fraction oforganochlorine pesticides is highly correlated with the mineral content; certaincorrelation was obtained between dissolvable fraction and the moisture content; noprominent effect was obtained about the acidity and cation exchange capacity on thefraction pattern.