摘要
以含1,2-二氯乙烷等10种有机物污染土壤异位修复后回填为例,采用层次化方法评估将按原厂址健康风险评价确定的修复目标进行达标修复后的土壤回填对回填区地下水下游700 m处饮用水井水质的影响.第一层次预测结果显示8种污染物在回填土层淋溶液中的浓度将超过评价标准,可能对目标水井水质造成污染.考虑回填区非饱和带土壤的吸附截留进行第二层次评价的结果显示,到达回填区地下水水面处浓度依然超过评价标准的污染物降低至6种,不能排除对目标水井的水质影响.进一步考虑地下水混合稀释进行第三层次评估的结果显示,经地下水混合稀释后,超过评价标准的污染物降低至4种.最后,考虑饱和带吸附截留作用进行第四层次评估的结果显示,目标水井中超过评估标准的污染物仅1种.由此可见,随着评估层次的不断深入,虽然所需开展的工作及获取的场地参数增加,但是污染物预测浓度更接近目标预测点的浓度,需调整修复目标的污染物数量逐渐减少,污染防治成本将逐渐降低.
The tiered approach for assessing the impact of backfilling treated contaminated soil on groundwater was presented in details with a case study. The soil was contaminated by 1,2-dicholorenthane and 9 other organic pollutants and had been remediated before backfilling to meet the pre-set remediation goals based on health risk assessment. The results from tiered I assessment indicate that the concentrations of 8 contaminants in the leachate of the backfilling soil layer would exceed the assessment standards probably leading to groundwater contamination. However, the results from tiered Ⅱ assessment, in which the adsorption and retardation of vadose zone soil was taken into account and the concentrations of pollutants reaching the groundwater table were predicated, reveal that only the concentrations of 6 contaminants would exceed the assessment standards. Further, taking the dilution and mixing of the groundwater into consideration, tiered Ⅲ assessment was adopted and the results reveal that only 4 contaminants were beyond the standards. Finally, tiered IV assessment, aiming at predicting the concentration at the target well downstream, was carried out by considering the retardation of contaminants in saturated layer, and the results indicate only 1 pollutant was above the assessment standard. Therefore, it can be seen that the predicted concentrations of the target pollutants at advanced assessment levels will be closer to those at the target drinking water well and the amount of contaminants whose initially-set remediation goals need to be modified will decrease correspondingly, indicating the reduction in pollution prevention cost, although more efforts should be made and more field data should be collected to implement the advance assessment level.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2013年第3期907-913,共7页
Environmental Science
基金
北京市科委重大项目(D08040900360804)
环境保护公益性行业科研专项(201009032)
关键词
达标修复
土壤回填
地下水
影响评估
层次化方法
remediation meeting targets
soil backfilling
groundwater
impact assessment
tiered approach
作者简介
作者简介：钟茂生（1986-），男，硕士，主要研究方向为污染场地调查评估与修复，E-mail：zzmmss1986@126．com.
通讯联系人，E-mail：jl-iep@rip．163．com.
