Department of Nursing, Fooyin University, Kaohsiung City 831, Taiwan.
Graduate Institute of Applied Geology, National Central University, Taoyuan City 320, Taiwan.
Sci Total Environ. 2018 Jun 15;627:1048-1057. doi: 10.1016/j.scitotenv.2018.01.294. Epub 2018 Feb 6.
A long-term groundwater quality survey in northeastern Taiwan's Lanyang Plain has revealed obvious contamination of the groundwater in some areas, with measured As concentrations in excess of the acceptable level of 10μg/L. Efforts for assessing the health risk associated with the intake of As through the drinking of contaminated groundwater are a necessary part of the important work of health risk management. However, the standard approach to assessing risks to human health does not adequately account for spatial heterogeneity in the measured As concentrations. Thus, this study applies two different kriging approaches to carry out a spatial analysis of the health risk associated with ingesting As through the drinking of groundwater in the Lanyang Plain. It is found that the indicator kriging (IK) approach, with occurrence probability threshold values of 0.4, 0.5 and 0.6 yields correct classification percentages of 75%, 68% and 61%, respectively, of unacceptable HQ zones. An HQ map prepared with the ordinary kriging (OK) approach shows a correct classification of unacceptable HQ zones of 80%. Considering that the OK approach does not require subjective selection of an occurrence probability threshold value as is the case with the IK approach and can yield a higher percentage of correct classification for unacceptable HQ zones, it is recommended as a more direct and reliable method for spatial analysis of human health risk due to arsenic exposure through the drinking of groundwater. The results show that the geographical distribution of unacceptable HQ zones is concentrated in the eastern part of the study area, which includes the high-population density townships. In other words, 34% of the people had access to groundwater where the HQ was >1. The results of this type of spatial health risk assessment can provide a basis for improving the decision-making process for health risk management.
台湾东北部兰阳平原的一项地下水水质长期调查显示，一些地区的地下水受到明显污染，测得的砷浓度超过 10μg/L 的可接受水平。评估通过饮用受污染地下水摄入砷相关的健康风险是健康风险管理的重要工作的必要组成部分。然而，评估人类健康风险的标准方法不能充分考虑测量砷浓度的空间异质性。因此，本研究应用两种不同的克立格方法对兰阳平原饮用地下水摄入砷相关的健康风险进行空间分析。结果表明，指示克立格（IK）方法，当出现概率阈值为 0.4、0.5 和 0.6 时，不可接受 HQ 区的正确分类百分比分别为 75%、68%和 61%。普通克立格（OK）方法生成的 HQ 图显示不可接受 HQ 区的正确分类为 80%。考虑到 OK 方法不需要像 IK 方法那样主观选择出现概率阈值值，并且可以为不可接受的 HQ 区产生更高的正确分类百分比，因此建议将其作为一种更直接、可靠的方法，用于通过饮用地下水摄入砷对人体健康风险进行空间分析。结果表明，不可接受 HQ 区的地理分布集中在研究区域的东部，包括人口密度较高的乡镇。换句话说，有 34%的人可以获得 HQ>1 的地下水。这种空间健康风险评估的结果可以为改善健康风险管理的决策过程提供依据。
