土壤重金属健康风险时空预测及管控目标研究

土壤重金属健康风险研究对于保障区域人体健康、完善土壤风险防控体系和维护土壤可持续利用等具有积极的意义。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土壤重金属管控目标。研究结果表明，Cr、As、Pb、Cd和Hg在2007年至2017期间的年平均累积速率分别为-0.711、0.558、0.0055、-0.0858和0.0133 mg·(kg·a)-1，且Pb、Cd、As和Hg在2007年和2017年均处于中度或高度变异；Cr和As的儿童致癌风险在2017年的最小值分别为13.308×10-6和4.548×10-6，Pb对应的儿童非致癌风险的最大值1.366，且高于1的点位占所有调查点位的11.58%，Cr、Pb和As是六合区土壤重金健康风险的主要风险特征因子；2017年至2030年，Pb的非致致癌风险呈上升趋势，且在2025年和2030年Pb的最大值分别为1.60和1.84，高于1点位占比分别为20.00%和28.42%，Cr和As的儿童致癌风险总体呈下降趋势，但是其平均值分别为19.5693×10-6和10.0926×10-6、18.6698×10-6和9.5635×10-6，总体水平依然高于健康风险管控目标；基于2030年致癌风险管控目标下，Cr和As的含量需要降低到37.500和4.1667 mg/kg，Cr和As的降低速率分别处于0.9783 ~ 8.1218 和0.3050 ~ 0.7472 mg·(kg·a)-1，对应的均值分别为3.1755和0.3813 mg·(kg·a)-1，其Cr降低速率高值区域主分别主要分布在以六合经济开发区周边的区域以及冶山镇南部区域、As主要分布在以竹镇镇西部、冶山镇北部以及马鞍街道北部的六合区北区区域。

Spatio-temporal Prediction and Control Objectives for Health Risk of Soil Heavy Metals

Health risk of soil heavy metals is significant to protect regional human health, improve the soil risk management system and maintain the sustainable utilization of soil. The health risk and its spatio-temporal were predicted and analyzed with the support of black box theory, health risk assessment model and inverse distance weight interpolation method Based on monitoring data of Cr, Pb, Cd, As and Hg in soil. Furthermore, the control objectives of soil heavy metals were obtained from the perspective of health risk. The results showed that the average annual accumulation rates of Cr, As, Pb, Cd and Hg were -0.711, 0.558, 0.0055, -0.0858 and 0.0133 mg·(kg·a)-1with the moderate or high variation of from 2007 to 2017. The minimum carcinogenic risk of Cr and As and the maximum for children were 13.308×10-6, 4.548×10-6 and 1.366, and the points with for non-carcinogenic risk of Pb being higher than 1 accounted for 11.58% of all survey points. Thus, Cr, Pb and As are the main health risk characteristic factors of soil heavy metal health risk in Liuhe District. The non-carcinogenic risk of Pb showed an upward trend from 2017 to 2030with the maximum value of 1.60 and 1.84 and the points higher than 1 accounting for 20.00% and 28.42% in 2025 and 2030, and the overall carcinogenic risk of Cr and As for children showed a downward trend from 2017 to 2030 with the average values were 19.5693×10-6 and 10.0926×10-6 in 2025 and 18.6698×10-6 and 9.5635×10-6 in 2030. Based on control targets of 5×10-6 and 8×10-6 for children carcinogenic risk of As and Cr, the contents of Cr and As in soil need to be reduced to 37.500 and 4.1667 mg·kg-1 and the reduction rates were in the range of 0.9783 ~ 8.1218 and 0.3050 ~ 0.7472 mg·(kg·a)-1with the corresponding mean values of 3.1755 and 0.3813 mg·(kg·a)-1, respectively. Furthermore, The regions with high Cr reduction rates are mainly distributed around Liuhe economic development zone and the south of Yeshan Town, and As are mainly distributed in the north of Liuhe District, including the west of Zhuzhen town, The north of Yeshan town and? the north of Maan street. The results could provide a practical basis for the formulating the management and control countermeasures of regional soil heavy metal risk and the improvement of risk management and control system.