珠江三角洲土壤中氯丹的残留特征

CHLORDANE RESIDUE IN SOILS OF THE PEARL RIVER DELTA

对珠江三角洲三种主要类型的土壤（水稻土、菜园土和非耕作土），共计74个样品进行了顺式氯丹（CC）和反式氯丹（TC）的GC-MS的定量分析。结果显示：珠江三角洲土壤中氯丹的检出率较高，CC和TC皆为100％。反式氯丹（TC）和顺式氯丹（CC）的浓度范围分别为〈0．01—13．70ngg^-1和〈0．01—15．70ngg^-1，其中多数样品中该类化合物浓度集中在0．1～1．0ngg^-1浓度段。在定量分析的基础上，利用手性色谱柱对这两种手性化合物的对映体值进行了测定。通过化合物浓度与其对映体比值的对比，认为个别高值点主要受氯丹使用的影响，其手性化合物对映体比值（EF）接近原始值（0．5）。氯丹在土壤中的浓度值与土壤中的有机碳含量无相关性。

A total of 74 soil samples were collected from three major types of soils, garden soil, paddy soil and natural soil in the Pearl River Delta, for quantitative analysis of residues of cis-chlordane （CC） and trans-chlordane （TC）, and for enantiomeric ratios of those two chiral organochlorine pesticides. Results indicate that the concentrations of TC and CC were in the range of 〈 0.01 - 13.70 and 〈 0.01 - 15.70 ngg^-1, respectively, and appeared to be log-normally distributed. And of above 80 percent of the samples, concentrations were in the range of 0.1 - 1.0 ng g^-1. The special high levels of chlordane in soils might be attributed to the use of the substance in the vicinity. Pesticide residues were not proportional to soil organic carbon content.