Aiken Miranda L, Ying Samantha C
School of Earth and Environmental Sciences, Schmid College of Science and Technology, Chapman University, Orange, California 92866, United States.
Schmid College of Science and Technology, Chapman University, Orange, California 92866, United States.
ACS ES T Water. 2023 May 8;3(8):2168-2178. doi: 10.1021/acsestwater.3c00007. eCollection 2023 Aug 11.
Manganese (Mn) is currently regulated as a secondary contaminant in California, USA; however, recent revisions of the World Health Organization drinking water guidelines have increased regulatory attention of Mn in drinking water due to increasing reports of neurotoxic effects in infants and children. In this study, Mn concentrations reported to California's Safe Drinking Water Information System were used to estimate the potentially exposed population within California based on system size. We estimate that between 2011 and 2021, over 525,000 users in areas with reported Mn data are potentially exposed to Mn concentrations exceeding the WHO health-based guideline (80 μg L), and over 34,000 users are potentially exposed to Mn concentrations exceeding the U.S. Environmental Protection Agency health-advisory limit (300 μg L). Water treatment significantly decreased Mn concentrations compared to intake concentrations for all system sizes. However, smaller water systems have a wider range and a higher skew of Mn concentrations in finished water than larger systems. Additionally, higher Mn concentrations were found in systems above the maximum contaminant levels for chromium and arsenic. The treatment of these primary contaminants appears to also remove Mn. Lastly, data missingness remains a barrier to accurately assess public exposure to Mn in very small, small, and medium community water system-delivered water.
锰（Mn）目前在美国加利福尼亚州被列为二级污染物；然而，世界卫生组织饮用水准则最近的修订增加了对饮用水中锰的监管关注，因为有越来越多关于婴儿和儿童神经毒性影响的报告。在本研究中，向加利福尼亚州安全饮用水信息系统报告的锰浓度被用于根据系统规模估算加利福尼亚州内可能暴露的人群。我们估计，在2011年至2021年期间，报告有锰数据的地区超过52.5万用户可能暴露于超过世界卫生组织基于健康的准则（80微克/升）的锰浓度，超过3.4万用户可能暴露于超过美国环境保护局健康咨询限值（300微克/升）的锰浓度。与所有系统规模的进水浓度相比，水处理显著降低了锰浓度。然而，较小的供水系统成品水中锰浓度的范围更广且偏度更高。此外，在超过铬和砷最大污染物水平的系统中发现了更高的锰浓度。对这些主要污染物的处理似乎也能去除锰。最后，数据缺失仍然是准确评估非常小、小和中等社区供水系统供应的水中公众接触锰情况的一个障碍。
