珠江三角洲地区典型类型土壤中DDT残留及其潜在风险

DDT Residual in the Typical Soil Types of Pearl River Delta Region and Its Potential Risk

珠江三角洲地区有机氯农药的残留一直以来受到关注。本研究通过对该地区30个采自典型类型土壤剖面的表层样品进行DDT的含量和组成分析，初步揭示了珠江三角洲地区的DDT残留情况及其潜在生态风险。研究结果表明：珠江三角洲地区6种典型类型土壤中，除滨海砂土外，其他5种土壤都能够检测到DDT的存在。DDT含量在0．16～32．8μg／kg之间，以o,p′-DDT的检出率最高，其次为p,p′-DDE。该地区可能存在通过使用三氯杀螨醇带入微量DDT的情况。此外，个别采样点存在低剂量DDT的潜在生态风险，需要做进一步探讨。

The residual of organochlorine pesticides in the environmental medium of Pearl River Delta （PRD） has attracted much attention in recent years. Thirty surface soil samples from the typical soil types of the PRD were selected to measure the contents of DDT and its metabolic compounds in this study. The objective was to determine the DDT residual in the soils at a regional scale and to assess the potential risk preliminarily. The results indicated that DDT can be detected in all typical soil types except for the littoral sandy soil. Total content of DDT in the soils ranged from 0.16μg/kg to 32.8 μg/kg, and o,p＇-DDT was the predominant compound among the four homolog. Trace amount of DDT was assumed to be sourced from the dicofol in this region. In addition, potential secondary poisoning of top predator might be caused by the low content of DDT of the soil in some sampling locations. Therefore, further researches are suggested to evaluate the probability of the risk.