| 基于参数优化和蒙特卡罗模拟的砷污染地块健康风险评估 |
| 摘要点击 1281 全文点击 230 投稿时间：2023-02-21 修订日期：2023-04-17 |
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| 中文关键词 污染地块 砷（As） 参数修正 相对生物有效性（RBA） 概率风险评估 |
| 英文关键词 contaminated site arsenic （As） model parameters modification relative bioavailability（RBA） probabilistic risk assessment |
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| 中文摘要 |
| 风险评估是污染地块风险管理的关键环节.而在具体As污染地块管理实践中，基于污染物总量和默认参数的方法难以获得符合实际的健康风险，进而不能达到后期修复治理等管控要求，目前越来越多的研究通过考虑生物有效性、修正参数、结合概率模型等方法开展风险评估.以某大型As污染地块为典型案例，布设432个采样点并采集不同深度土壤样品，分析As污染程度及分布特征，通过文献调研和Monte Carlo模拟修正模型参数，并在此基础上开展概率风险评估，比较探讨传统方法与概率方法对健康风险评估结果的影响.结果表明，研究区域表层土壤ω（As）范围为2.70~97.0 mg·kg-1，空间变异系数为0.61，空间连续性较弱.传统风险评估方法所得致癌风险和危害指数分别为2.12E-4和8.36，高估了实际风险水平，结合模型参数修正和概率风险评估发现，成人和儿童的非致癌风险处于可接受水平，致癌风险相较传统方法降低近1个数量级.考虑As相对生物有效性（RBA）后，总致癌风险的95%分位值为1.24E-5，相较未修正对应的风险值1.95E-5，降幅可达36.41%.研究区域土壤As对成人和儿童的致癌风险超过可接受风险水平1E-6，其中经口摄入土壤是主要暴露途径.此外，敏感性分析结果显示，As含量、每日土壤摄入量和儿童暴露期对健康风险影响相对较大.研究结果可为砷污染地块精准风险评估提供方法理论依据，并为地块的精细化风险管控提供思路. |
| 英文摘要 |
| Risk assessment is a critical part of risk management for contaminated sites. However， in the specific management practice of As-contaminated sites， it is difficult to obtain realistic health risks for contaminated sites based on the total amount of pollutants and determined values of the model， thus preventing the control requirements of later remediation to be met. An increasing number of studies have recently been conducting risk assessments by considering bioavailability， modification parameters， and combined probabilistic models. To improve the accuracy of risk assessment results， taking a large As-contaminated site as a case， 432 sampling sites were set up and collected at different depths to analyze the level and distribution characteristics of As pollution， and probabilistic risk assessment was conducted with the modification of model parameters through literature research and Monte Carlo simulation. Then， the impact of traditional methods and probabilistic methods on health risk assessment was explored in comparison. The results indicated that ω（As） in the top soil of the study area ranged from 2.70-97.0 mg·kg-1， with a spatial variation coefficient of 0.61 and weaker spatial continuity. The carcinogenic risk and hazard index obtained by the traditional risk assessment method were 2.12E-4 and 8.36， respectively， which obviously overestimated the actual risk level and were not conductive to the refined management of As-contaminated sites. Combined with modification of model parameters and probabilistic risk assessment， the non-carcinogenic risk for adults and children was found to be at an acceptable level， and the carcinogenic risk was reduced by nearly an order of magnitude compared to that in the conventional method. Considering the relative biological effectiveness （RBA） of As， the 95% quantile of the total carcinogenic risk was 1.24E-5， a reduction of up to 36.41% compared to the uncorrected corresponding risk value of 1.95E-5. The carcinogenic risk of soil As for adults and children in the study area exceeded acceptable risk levels 1E-6， with oral ingestion of soil being the primary route of exposure. In addition， the results of the sensitivity analysis of the parameters showed that As concentration， daily oral ingestion rate of soils， and exposure duration of children had relatively larger effects for health risks. This work will provide a methodological and theoretical basis for achieving accurate risk assessment of As-contaminated sites and provide concepts for refined risk management. |
