同位素溯源技术在土壤与地下水环境污染责任划分中的应用

Application of isotope traceability techniques in the delineation ofresponsibility for environmental pollution of soil and groundwater

近年来我国污染防治攻坚战取得重大胜利,作为污染防治最前沿的土壤和地下水环境污染状况调查及环境损害责任划分工作,面临着诸多技术方法的创新。污染物溯源、污染地块的损害鉴定,一直以来都是污染调查工作中的薄弱且争议较多问题。尤其是准确的判断污染扩散成因、环境特征参数、暴露受体参数、影响范围都是需要多学科相互验证才能实现的。利用同位素溯源测定技术可以追溯源头污染物,明确环境污染损害责任主体。本文以新疆某油气生产环境污染事故场地石油烃污染为例,基于同位素溯源测定技术建立污染物运移扩散模型,在调查区上游背景值土壤采集点采集28个样品进行δ^(13)C丰度分析,根据测定结果进行对比分析,对比不同的污染来源后确定污染源。结果显示:根据完成的数值模型预测评价结合稳定碳同位素比值验证,判定下游S04监测井中的石油烃与事故现场污染源并非同一来源,而与附近居民区渠系内地表水补给有很大的关联,渠系周边有机械维修厂和农机堆放区,水渠周边有排放废弃机油和其他类油污的痕迹。研究结论为后续的治理和责任主体划分提供技术依据和佐证。

In recent years,China's pollution prevention and control battle has achieved a major victory,as the forefront of pollution prevention and control of soil and groundwater environmental pollution status investigation and environmental damage liability delineation work,facing a number of technical methods of innovation.The traceability of pollutants and the identification of damage to contaminated land have always been weak and controversial issues in pollution investigations.In particular,accurate judgement of the causes of pollution dispersion,parameters of environmental characteristics,parameters of exposed receptors,and the scope of influence are all required for multidisciplinary mutual verification to be realized.The use of isotope traceability measurement technology can trace the source pollutants and clarify the main body of responsibility for environmental pollution damage.This paper takes petroleum hydrocarbon pollution at an oil and gas production environmental pollution accident site in Xinjiang as an example,establishes a pollutant transport and diffusion model based on isotope traceability measurement techniques,collects 28 samples for δ^(13) C abundance analysis at the soil collection point of background value in the upstream part of the investigation area,and carries out a comparative analysis based on the results of the measurements,and determines the source of pollution after comparing the different sources of pollution.The results show:Based on the completed numerical model prediction evaluation combined with the verification of the stable carbon isotope ratios,it was determined that the petroleum hydrocarbons in the downstream S04 monitoring well are not from the same source as the pollution source at the accident site,but rather are highly correlated with the surface water recharge in the drainage system in the nearby residential area,where there is a machinery repair shop and agricultural machinery stockpile area around the drainage system,and traces of discharged waste motor oil and other types of oil pollution around the water channel.The conclusions of the study provide the technical basis and support for subsequent governance and the delineation of responsible parties.