广东省典型区域农业土壤中有机氯农药含量及其分布特征

Residues and Distribution Characteristics of Organochlorine Pesticides in Agricultural Soils from Typical Areas of Guangdong Province

2002年10月至2005年11月采集广东省典型区域(汕头市、湛江市、东莞市、惠州市、中山市、珠海市和佛山市顺德区)的农业土壤表层(0～20cm)样品444个,采用气相色谱方法对土壤中17种有机氯农药(OCPs)进行分析,初步揭示了广东省农业土壤中OCPs的含量及其分布特征。结果表明,研究区农业土壤中OCPs的检出率为99.8%,含量范围在ND～936.94ng·g-1之间,主要残留物为硫丹硫酸盐、甲氧滴滴滴、硫丹Ⅰ和p,p′-DDE,这4种化合物残留量之和占OCPs残留总量的50%以上;α-HCH、p,p′-DDE、艾氏剂、硫丹Ⅱ和β-HCH的检出率较高(大于80%)。不同土壤利用类型中,OCPs残留量排序为菜地>香蕉地>水稻田>旱坡果园地>甘蔗地,佛山市顺德区和汕头市两地土壤中OCPs残留量明显高于本研究区的其他地方。分别有98.4%和94.1%土壤样本的HCHs和DDTs残留量达到国家《土壤环境质量标准》(GB15168—1995)一级标准(<50ng·g-1),土壤中HCHs和DDTs残留污染较轻。

Totally 444 samples of surface agricultural soils （0～20cm depth） were collected in typical regions of Guangdong province from October 2002 to November 2005. The residues and distribution characteristics of 17 kinds of organochlorine pesticides （OCPs）in the collected soil samples were analyzed with gas chromatography. The results showed that OCPs were found in 99.8% of the collected soil samples and ranged from ND to 936.94 ng·g^-1. The endosulfan sulfate, methoxychlor, a-endosulfan and p,p＇-DDE were the main components, and their contribution to the residues of OCPs was over 50% .The α-HCH, p,p＇-DDE, aldrin, b-endosulfan and β-HCH were found over 80% in the collected soil samples. The concentrations of OCPs in the collected soil samples related with different types of land use and descended in the order： vegetable soil〉banana soil〉paddy soil〉orchard soils〉 sugarcane soil. The concentrations of OCPs in the samples from Shunde and Shantou were higher than those from remote sites. The concentrations of HCHs in 98.4% of the samples and the concentrations of DDTs in 94.1% of the samples were lower than 50 ng·g^-1, which reached the first level of the National Soil Environment Quality Standard （GB 15618-1995）. The pollutions of HCHs and DDTs were generally slight in agricultural soils from the typical areas of Guangdong province.