【作者】 赵亮；

【导师】 李朋富； 周军英；

【作者基本信息】 南京大学 ， 制药工程（专业学位）， 2012， 硕士

【摘要】 农药为防治农作物病虫草害,保证作物高产方面发挥着巨大作用。但农药是把双刃剑,在带给人们巨大经济效益的同时也对生态环境造成了严重威胁。进入环境中的农药可能会对地下水、地表水及环境生物产生危害影响。因此,如何避免和减轻农药使用对生态环境的危害已成为广泛关注和亟待解决的重大环境问题。生态风险评价近年来在农药的环境安全管理中越来越得到重视,已成为许多国家农药环境安全管理的有力技术支撑。地下水是水资源的重要组成部分,是人民生活和工农业用水的重要水源。地下水通常较地表水难以污染,但是一旦被污染后,其不良后果很难消除。农药在田间使用后,可通过降雨、淋溶等途径进入地下水体,从而降低地下水质量,影响地下水功能。不适当地使用农药已经并正在使许多宝贵的地下水源因污染而无法利用。应用地下水风险评价技术可以预测农药使用可能对地下水产生的危害和影响,为污染预防提供技术支持。因此开展地下水风险评价技术研究具有重要意义。农药地下水风险评价与地表水风险评价有所不同,地表水风险评价的生态受体包括人体和多种环境生物,而地下水风险评价中目前只关注人体健康,因此,暴露评价技术是地下水风险评价技术的关键点。本论文围绕地下水暴露评价开展了以下几方面研究：(1)暴露评价模型筛选研究对目前国外(美国、欧盟和其它国家)已经开发的各层次的地下水暴露评价模型进行了分析和比较,包括第Ⅰ层次的筛选模型(美国的SCI-GROW、Tier I Eco-Risk Calculator,欧盟的MACRO、PEARL、PELMO和PRZM_GW)和第Ⅱ层次的暴露评价模型(美国的PRZM3(PRZM+VADOFT)和ADAM),在比较了各模型的输入参数、模拟过程、评价结果、评价层次等方面后,最终筛选出适合我国实际情况的第1层次的筛选模型SCI-GROW和第Ⅱ层次的暴露评价模型PRZM3和ADAM。SCI-GROW模型需要输入参数较少,这4种参数考虑了农药的移动性和降解性,以及农药的施用量和施用次数,能够直观反映农药在地下水中的暴露浓度,适合作为第1层次的筛选模型。PRZM和ADAM考虑的因素较多,模型较复杂,预测结果更为精细。其中PRZM主要模拟农药被施用于旱地作物后在作物根区中的行为,ADAM主要模拟农药在地下蓄水层中的稀释、分配、持留及转运情况。因此PRZM-ADAM的连接模型可以预测农药被施用于旱地作物后淋溶进入地下水的行为和残留浓度,适合作为第Ⅱ层次的暴露评价模型。(2)我国农药地下水标准暴露场景体系框架构建目前我国还没有一套完整的农药标准暴露场景。本论文首先在中国建立了一套旱地作物-地下水暴露场景体系。以“现实中最坏条件”原则作为场景建立时应遵循的原则,即在确定场景包含的各因素的特征时要尽可能地选择一些现实中存在的、“最坏”的特征,即最有利于造成农药污染的特征。在此原则的基础上,首先根据气候条件将全国划分为5个场景区,然后在每个场景区中确定一定数量的场景点。最终构建了中国旱地作物-地下水暴露场景体系,包括5个场景区(西北区、东北区、华北区、场景流域区、华南区),10个场景点(陕西榆林、内蒙古通辽、辽宁沈阳、河南南阳、山东菏泽、江苏风险、江西赣州、安徽安庆、湖北黄冈、海南儋州),共6种场景作物(玉米、小麦、花生、油菜、棉花、甘蔗)。(3)地下水暴露模拟外壳构建及参数敏感性分析为了在我国开展高层次的农药风险评价,与美国Waterborne环境公司共同开发了农药风险评价暴露模拟外壳(Pesticide Risk Assessment Exposure Simulation Shell, PRAESS)。PRAESS中用于地下水暴露评价的模型是PRZM-ADAM模型。将PRZM和ADAM的耦合模型与地下水场景结合,可以预测农药在地下水中的暴露浓度。本论文采用单次单因子法对PRZM-ADAM模型的主要输入参数进行了敏感性分析,结果表明显示各参数的相对敏感度大小顺序为：土壤降解半衰期(或施用量)>施用量(或土壤降解半衰期)>Koc>地下水中降解半衰期。同时对外壳程序进行了验证工作,包括程序编码验证(Verification)和适用性分析(Validation),最终确认PRAESS的可用性。(4)地下水暴露评价技术应用研究(地下水高污染风险品种筛选)本论文应用构建的场景和外壳程序对我国常用农药品种对地下水污染的急性和慢性风险进行了评价。首先应用PRAESS得到农药在地下水中的暴露浓度,然后根据WHO推荐的方法计算出各农药的指导限值,分别将峰值预测浓度、年均值预测浓度与限制浓度进行比较,根据计算出的风险商值判断出各农药对地下水污染的急性和慢性风险等级,列出了对地下水污染存在急性和慢性高风险的农药品种名单,并对这些农药在地下水易受污染的一些地区的使用提供了参考建议。地下水暴露评价研究是一项很有意义的工作,本论文做了一些初步的工作,希望对我国地下水暴露评价研究工作的开展打下一定的基础。更多还原

【Abstract】 Pesticides play an important role in controlling crop pests and smothering and ensuring high crop yield. But pesticide is a double-edged sword which simultaneously brings huge economic benefits to people and creates a serious threat to ecological environment. The pesticides that enter into the environment may generate significant adverse effects to groundwater, surface water and environmental organism. Therefore how to avoid and mitigate the adverse effects caused by pesticide application has become a major environmental problem concerned widely and be solved. Ecological risk assessment has been paid more and more attentions in pesticide environmental safety management in recent years and become a strong technical support of pesticide environmental safety management of many countries.Groundwater is an important part of water resources and an important source of water in people’s lives and industrial and agricultural water. Groundwater is more difficult to be contaminated than surface water. But once contaminated, it is difficult to eliminate the adverse consequences. Pesticides can enter into groundwater body by Rainfall and leaching after they used in field, which lowers the groundwater quality and affects groundwater function. The application of technology of groundwater risk assessment could predict or assess the hazard and effect of pesticide application on groundwater and can provide technical support for pollution prevention. Therefore, it is significant to carry out groundwater risk assessment technical research.Pesticide groundwater risk assessment is different from surface water risk assessment. The ecological receptors of surface water risk assessment consist of humans and a variety of environmental organisms while groundwater risk assessment only focuses on human health currently. Therefore exposure assessment technology is the key point of groundwater risk assessment technology. This thesis centered on the groundwater exposure assessment and carried out the following researches:(1) Research on screening of exposure assessment modelsAnalyzed and compared different tier groundwater exposure assessment models developed by U.S., EU and other countries, including tier Ⅰ screening models (SCI-GROW and Tier Ⅰ Eco-Risk Calculator by U.S., MACRO, PEARL, PELMO and PRZM_GW by EU) and tier Ⅱ exposure assessment models (PRZM3(PRZM+VADOFT) and ADAM by U.S.). After compared the input parameters, simulated behaviors, assessment results and assessment tiers of each models, finally screened out SCI-GROW as tier Ⅰ screening model and PRZM3-ADAM as tier Ⅱ exposure assessment model adapted Chinese actual conditions. SCI-GROW requires less input parameters and these four parameters consider the mobility and degradation of pesticides and application rate and number of applications, which can directly reflect the exposure concentrations of pesticides in groundwater. Therefore it is suitable as tier Ⅰ screening model. PRZM and ADAM consider many factors and are more complicated and they predict results are finer. PRZM mainly simulates the pesticide behaviors after applied in dryland crops in the crop root zone. ADAM mainly simulates the dilution, partitioning, persistence and transport of pesticide in aquifer. Therefore PRZM-ADAM coupled model can predict the pesticide behaviors and residual concentrations in aquifer after applied in dryland crops. Therefore it is suitable as tier Ⅱ exposure assessment model.(2) Establishment of Chinese standard pesticide groundwater scenario system frameworkPresently China has not a set of complete standard pesticide exposure scenario. This thesis established a set of dryland-groundwater scenarios in China for the first time."The realistic worst case" principle is the principle for scenario establishment, which means should choose some real," the worst" features as much as possible in determining the properties of the factors contained in the scenario, namely properties which could easily lead to pesticide contamination. On the basis of the principle, firstly divided the whole country into5scenario zones based metrological conditions, then determine a certain number of scenario sites in each scenario zone. Finally established Chinese dryland-groundwater scenarios system, including5scenario zones (Northeast, Northeast, North China, Yangtze River Basin and Southeast),10scenario sites (Shaanxi Yulin, Inner Mongolia Tongliao, Liaoning Shenyang, Henan Nanyang, Shandong Heze, Jiangsu Fengxian, Jiangxi Ganzhou, Anhui Anqing, Hubei Huanggang and Hainan Danzhou) and totally6scenario crops (corn, wheat, peanut, rapeseed, cotton and sugar cane).(3) Construct and verification/validation of groundwater exposure simulation shellIn order to conduct higher tier pesticide risk assessment in China, Pesticide Risk Assessment Exposure Simulation Shell was co-developed by the company with U.S. Waterborne Environmental Inc.. The model applied in groundwater exposure assessment in PRAESS is PRZM-ADAM model. Combined PRZM-ADAM coupled model with groundwater scenario, the exposure concentration of pesticide in groundwater can be predicted. OAT (One factor at a time) method was used in this thesis to perform sensitivity analysis to the major input parameters of PRZM-ADAM. The results showed that the order of the relative sensitivity of each parameter is:Soil DT50(or application rate)> application rate (or Soil DT50)> Koc> DT50in groundwater. Meanwhile the verification and validation of shell program were performed and finally the validation of PRAESS was verified.(4) Research on application of groundwater exposure assessment technology (screening of pesticide with high contamination risk)Established scenario and shell program were used in this thesis to assess the acute and chronic risks of contamination for groundwater caused by pesticide varieties commonly used in China. Firstly applied PRAESS to get the exposure concentration of pesticide in groundwater, and then calculated the guidance value of a pesticide on the basis of the method recommend by World Health Organization. Divided the predicted peak concentration and annual concentration by the guidance value respectively and judge the acute and chronic risk level of pesticides causing groundwater contamination according to the calculated risk quotients. At last listed the lists of pesticide varieties may result in acute and chronic high contamination risk to groundwater and provided some references for the use of pesticide in the areas that is vulnerable to be contaminated in groundwater caused by pesticide application.The research on groundwater exposure assessment is a significant work. This thesis has done some preliminary works aimed to lay a certain foundation to carrying out the research work on groundwater exposure assessment in China.更多还原