沈阳市细河周边农田土壤和大气中有机氯农药和多氯联苯初步研究

在2010年5月调查了沈阳市细河沿岸表层土壤中有机氯农药(OCPs)和多氯联苯(PCBs)的污染现状,评价土壤中OCPs残留的生态风险。沈阳细河沿岸表层土壤中HCHs浓度范围分别为2.32～15.90 ng/g,平均浓度为8.99ng/g。DDTs浓度范围分别为9.06～111.6 ng/g,平均浓度为37.08 ng/g。7种PCBs异构体总平均浓度为1.01ng/g,大部分采样点OCPs和PCBs未超过国家土壤环境质量标准,推断近期可能有林丹的使用但没有新的DDTs污染源输入,但个别地点土壤中的DDTs残留浓度对生态系统健康构成了潜在的威胁。大气蒸汽态HCHs浓度为18.97 ng/m3;DDTs浓度为42.27 ng/m3;PCBs浓度为20.59 ng/m3。研究表明大气长距离传输对该区域的OCPs污染也有较为明显的影响。初步运用逸度概念模型进行分析,发现HCHs和DDTs的逸出方向为从土壤向大气挥发。

Preliminary Study on Distribution of Organochlorine Pesticides and Polychlorinated Biphenyls in Surface Soils and Atmosphere Along the Xihe River in Shenyang City

The concentration of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in surface soils and atmosphere along the Xihe River in Shenyang city were determined to study the residual levels and environmental behaviors of these compounds. Concentrations of HCHs and DDTs were in the range of 2.32~15.90 ng/g with average value of 8.99 ng/g and 9.06~111.6 ng/g with average value of 37.08 ng/g, respectively. The mean concentration of 7 kinds of PCBs was 1.01 ng/g. Results showed that concentrations of OCPs and PCBs in most sampling sites did not exceed the limits of the national environment quality standards for soils. The results also indicated that although lindane might be used in recent years no DDTs input from new pollution sources were found. And DDTs residuals in soils from some sites posed a potential threatening to the ecosystem. The mean concentrations of HCHs, DDTs and PCBs in air samples were 18.97 ng/m³, 42.27 ng/m³ and 20.59 ng/m³ respectively, which means that long distance atmospheric transport of the OCPs may play a significant role in pollution in these areas. The fugacity model was used to study the environmental behaviors of HCHs and DDTs and escaping tendency of HCHs and DDTs from soils to ambient air was found in the studied area.