珠江八大入海口表层沉积物中DDTs和HCHs残留调查

于2010年8月-2011年5月4次采集珠江八大人海口表层沉积物，采用气相色谱-电子捕获（GC—ECD）法分析沉积物中DDTs（p，P’-DDE、P，P’-DDD、0，P’-DDT、P，P-DDT）和HCHs（α-HCH、β-HCH、γ-HCH、δ-HCH）的污染现状。结果显示，珠江8大人海口表层沉积物中DDTs总含量介于1．02—3．08μg·kg-1之间（以干质量计，下同），平均值为1．91μg·kg-1；HCHs总含量介于0．21—0．41μg·kg-1之间，平均值为0．31μg·kg-1。DDTs平均含量大于HCHs，其中P，P。DDT对污染的贡献最大，含量范围为ND～7．66μg·kg-1，平均值为2．12μg·kg-1。大部分样点伽（α-HCH）／w（γ-HCH）比值小于3，说明研究区α-HCH大都被降解，或者林丹正取代工业HCHs成为珠江口水环境中HCHs输入的主要来源；甜（DDT）／w（DDD＋DDE）比值大于2，表明沉积物中除早期农药残留外，仍然有新的DDTs类农药输入。

Residuals of Organochlorine Pesticides DDT and HCH in Surface Sediments of the Pearl River Estuary.

DichlorodiphenyltrichIoroethane （DDT） and hexachlorocyclohexane（HCH） , were common organochlorine pesticides extensively used for agriculture and vector control purposes due to their low cost and high effectiveness. As they are quite persistent, they become ubiquitous. And as they are potentially toxic and bioaccumulative in nature, they accumulate in organisms which once get exposed to them, and eventually cause adverse effects on both human and wildlife, such as cancer, damage to the nervous system, reproductive disorders, and disruption of the immune system. However, little has been done on this issue of the Pearl River estuary. So, during the period from August, 2010 to May, 2011, samples of surface sediments were collected four times at the Pearl River estuary for analysis of residues of DDTs（p ,p＇-DDE, p ,p＇- DDD, o,p＇- DDT, p,p＇- DDT） and HCHs（α- HCH,β - HCH, γ - HCH, δ - HCH） using the gas chromatograph-elec- tron capture （GC- ECD） method. Results show that total DDTs contents in the surface sediments from the Pearl River ranged from 1.02 to 3.08μg·kg-1 （ dry weight） and averaged 1.91 μg·kg-1 , and total HCHs contents ranged from 0, 21 to 0. 4μg·kg-1 and averaged 0. 31 μg·kg-1. DDTs were much higher than HCHs in average content, and p ,p＇ - DDT contributed the most, ranging from ND to 7.66μg·kg-1 , with a mean of 2. 12 μg·kg-1. In most of the sam- ples, w（a- HCH）/w（T- HCH） ratios were lower than 3, implying that α- HCH has mostly been degraded or that lindane is gradually taking the place of industrial HCHs as the major source of the pollutant HCHs in the water environment and w（DDT）/w（DDD ＋ DDE） ratios higher than 2, indicating that besides residuals of the pesticides used in the past, new input of DDTs type pesticides is found.