有机磷农药生产场地污染分布特征分析

针对有机磷农药 (OPPs) 生产场地存在污染的环境问题，以某农药生产企业污染地块为研究对象，分析了OPPs在土层中的空间分布和扩散规律。通过三维空间插值表征4种OPPs (甲拌磷、乙硫磷、对硫磷、特丁硫磷) 的污染分布。结果表明，土壤中甲拌磷、乙硫磷、对硫磷、特丁硫磷平均质量分数分别为697、356、19 102、63 mg·kg⁻¹。根据《EPA 区域筛选值》 (RSL-2017) 标准，4种OPPs质量分数均超标10倍以上。随着深度增加，4种OPPs呈现为先减小后增加再减少的趋势，与地层渗透系数变化规律一致。根据插值结果，污染羽面积大小排序为甲拌磷>特丁硫磷>乙硫磷>对硫磷，说明甲拌磷在土壤中的迁移能力最强。同一种OPPs质量分数在表层 (0~3 m) 与深层 (>3 m) 土壤中分布规律相似，局部出现质量分数高值 (超标>10倍) 。OPPs质量分数高值在土层阻隔和吸附作用下出现降低趋势。本研究结果可为农药污染地块调查及修复工程提供参考。

Analysis on Distribution Characteristics of Soil Organophosphorus Pesticides (OPPs) in The Production Site

Aiming at the environmental problem of organophosphorus pesticides (Opps) in the production site, the spatial distribution and diffusion of Opps in the soil layer were analyzed by taking the contaminated site of a pesticide production enterprise as the research object. In this study, the three-dimensional spatial interpolation was used to characterize the pollution distribution of four Opps (phorate, ethiophos, parathion and terbuthion) in soil of a pesticide production site. The average concentrations of phorate, ethiophos, parathion and terbuthion were 697, 356, 19 102 and 63 mg·kg−1, respectively. According to the standard content of EPA Regional Screening Value (RSL-2017), the concentrations of four Opps exceeded the standard values by a factor of > 10. As depth increases, four Opps exhibited a similar trend which first increased, and then decreased and again increased. Such variation was consistent with the permeability coefficient. The rank of pollution plume area was phorate > terbuthion > ethiophos > parathion, which indicated that the migration ability of phorate was the strongest in soil. The distribution trend of Opps concentration was similar in both surface layer (0~3 m) and deep layer (> 3 m) of soil with local high-concentration values (more than 10 times above the standard values). The concentration of high-concentrations Opps decreased under the action of soil barrier and adsorption. Results from the study could provide a scientific basic for the remediation of pesticides in the contaminated sites.