以土壤重金属Cr、Pb、Cd、As和Hg调查数据为基础，利用黑箱理论、健康风险评估模型和反距离权重插值法，预测分析了南京市六合区土壤重金属健康风险的时空变化特征，并基于健康风险视角探究了土壤重金属管控目标。结果表明：研究区重金属Cr、Pb、Cd、As和Hg在2007—2017年的平均累积速率分别为–0.711、0.558、0.006、–0.086和0.013 mg/(kg·a)，且Pb、Cd、As和Hg在2007年和2017年均处于中度或高度变异状态。Cr和As的儿童致癌风险在2017年的最小值分别为13.307×10^–6和4.548×10^–6，Pb儿童非致癌风险的最大值为1.366，且该风险值高于1的点位占所有调查点位的11.58%，Cr、Pb和As是六合区土壤重金属健康风险特征因子。2017—2030年，Pb儿童非致癌风险呈上升趋势，该风险值高于1的区域主要分布在大厂街道、长芦街道等六合区南部区域和以金牛湖街道为核心的六合区北部区域；Cr和As儿童致癌风险总体呈下降趋势，但对应的平均值分别高于8.670×10^–6和9.564×10^–6，其中Cr儿童致癌风险值高于20×10^–6的区域逐渐集中在以六合开发区和化工园区为核心的周边区域，As儿童致癌风险值高于10×10^–6的区域逐渐集中在以马鞍街道为核心的六合区北部区域。基于2030年健康风险管控目标，Cr和As的含量分别需降低到37.500 mg/kg和4.167 mg/kg，对应的年均降低速率分别处于0.978 ~ 8.122 mg/(kg·a)和0.305 ~ 0.747 mg/(kg·a)，且均值分别为3.176 mg/(kg·a)和0.381 mg/(kg·a)；Cr降低速率高值区域主要分布在六合开发区周边的区域以及冶山镇南部区域，As则主要分布在以竹镇镇西部、冶山镇北部以及马鞍街道北部为核心的六合区北部区域。

With the support of black box theory and the monitoring data of Cr, Pb, Cd, As and Hg in soil, the health risks and their spatio-temporal distributions in Luhe district of Nanjing City were assessed and predicted by using the health risk assessment model and inverse distance weight interpolation method, and then the corresponding control objectives were proposed. The results show that the average annual accumulation rates of Cr, As, Pb, Cd and Hg were –0.711, 0.558, 0.006, –0.086 and 0.013 mg/(kg·a)with the moderate or high variation of from 2007 to 2017, respectively. The minimum carcinogenic risks of Cr and As for children were 13.307×10^–6 and 4.548×10^–6 in 2017, respectively. The maximum non-carcinogenic risk of Pb for children was 1.366, and the sites higher than 1 account for 11.58% of all sites, which indicated Cr, Pb and As are the main health risk characteristic factors. From 2017 to 2030, the non-carcinogenic risk of Pb shows an upward trend, and the areas higher than 1 are mainly distributed in the southern area such as Dachang and Changlu streets and the northern area with the core of Jinniuhu street. The children carcinogenic risks of Cr and As show the downward trend, but their corresponding average values are higher than 8.670×10^–6 and 9.564×10^–6, respectively, and the areas with the children carcinogenic risk higher than 20×10^–6 for Cr are gradually concentrated in the surrounding areas of Luhe Economic Development Zone and Industrial Park, while the areas with the children carcinogenic risk higher than 10×10^–6 for As is gradually concentrated in the northern part including Ma'an street. Based on 2030 carcinogenic risk control targets, the contents need to be reduced to 37.500 mg/kgfor Cr and 4.167 mg/kgfor As, and their reduction rates should be reduced from 0.97 mg/(kg·a) to 8.122 mg/(kg·a) and from 0.305 mg/(kg·a) to 0.747 mg/(kg·a), with the corresponding mean values of 3.176 mg/(kg·a) and 0.381 mg/(kg·a) respectively. Furthermore, the regions with high Cr reduction rates are mainly distributed around Luhe Economic Development Zone and the south of Yeshan town, and the regions for As is mainly distributed in the north, including the west of Zhuzhen town, the north of Yeshan town and the north of Ma'an street.

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江苏省环保科研课题(2018001)，江苏省社会科学基金项目(22JZB001)和 NSFC-云南联合基金重点支持项目(U2102208)