天津市农村中小学校饮用水中三氯甲烷含量及健康风险评估

Concentration and health risk assessment of trichloromethane in drinking water for rural primary and middle school students in Tianjin

目的 评价天津市农村地区中小学饮用水中三氯甲烷(TCM)的分布特征及其健康风险,为改善农村学校饮用水安全提供科学依据。方法 于2023年4—6月(枯水期)和7—10月(丰水期),采用直接抽选法从天津市10个涉农行政区30所农村中小学校采集末梢水水样60份,参照《生活饮用水标准检验方法》检测其中TCM含量,采用美国环境保护署推荐的健康风险评估模型对中小学生经口摄入健康风险进行评估。结果 农村学校饮用水中TCM质量浓度范围为未检出~54.00μg/L,平均质量浓度为(13.44±14.88)μg/L;丰水期TCM质量浓度[12.90(1.40,32.28)μg/L]高于枯水期[2.40(1.40,18.13)μg/L](Z=-2.09,P<0.05);小学和中学TCM质量浓度分别为[3.38(1.40,20.75)μg/L]和[5.30(1.40,28.23)μg/L],差异无统计学意义(Z=0.50,P>0.05)。儿童经口暴露的致癌风险范围为3.84×10^(-7)~2.05×10^(-5),非致癌风险范围为0.00~0.16,均处于可接受水平,其中6~9岁儿童的潜在风险最高。结论 天津市农村中小学校饮用水中TCM呈不同程度检出,经口暴露的潜在健康风险应得到重视。应加强饮用水消毒副产物监测和管理,以降低儿童暴露风险。

Objective To evaluate the distribution characteristics and health risk of trichloromethane(TCM)in the drinking water supply of primary and middle schools in rural areas of Tianjin,so as to provide a scientific basis for improving drinking water safety in rural schools.Methods A total of 60 water samples from 30 rural primary and middle schools in 10 agricultural districts of Tianjin were collected from April to June(dry season)and July to October(wet season)in 2023 with direct selection method.The content of TCM was detected according to the Standard Methods for the Examination of Drinking Water,and a risk assessment method recommended by the United States Environmental Protection Agency was used to evaluate the health risk of TCM through oral exposure.Results The concentration of TCM in drinking water was no detection to 54.00μg/L,with an average of(13.44±14.88)μg/L,and the value was higher during the wet season[12.90(1.40,32.28)μg/L]than the dry season[2.40(1.40,18.13)μg/L](Z=-2.09,P<0.05).The concentration of TCM for primary and middle schools were[3.38(1.40,20.75)μg/L]and[5.30(1.40,28.23)μg/L]respectively,and there was no statistically significant difference between different types of schools(Z=0.50,P>0.05).The carcinogenic risk through oral exposure ranged from 3.84×10^(-7) to 2.05×10^(-5),while the non-carcinogenic risk ranged from(0.00-0.16),all within the acceptable range.Children aged 6 to 9 years old were at the highest risk.Conclusions TCM has been detected in the drinking water of rural primary and middle schools to a certain extent in Tianjin,and attention should be paid to the potential health risks of oral exposure.The monitoring and management of disinfection by-products in drinking water should be strengthened to further reduce the risk of exposure to children.