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Health risk assessment of emerging containants in water sources and treated drinking water(4/4)

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The purpose of this project was to assess the potential human risks and health effects from personal care and consumer products, emergency disinfection byproducts, and herbicides in source and drinking water. Based on literature reviews and research projects conducted by the Taiwan EPA, this project screened potential presences of various emerging micro pollutants for their occurrences in environmental waters and selected 17 chemicals to be included in the monitoring program in this study. A database has been prepared which provides the information concerning the chemical properities, toxicities, potential health effects, related treatment technologies and their environmental occurrences of the 17 emerging pollutants, which include five pesticides/herbicides (acephate, temephos, cartap, phosmet, and pendimethalin,); two cleaning products ( triclosan, and 1,4-dioxane,); one bactericide (carbendazim), seven emerging disinfection byproducts (dichloroacetonitrile, trichloroacetonitrile, bromochloroacetonitrile, dibromoacetonitrile, 1,1-dichloro-2-propanone, 1,1,1-trichloro-2-propanone and chloral hydrate), and two personal and beauty cosumer products (galaxolide and tonalide). In addition, eventhough that musk ketone and musk xylene were not included in the monitoring plan of this project, the chemical properities and potential health related information were also collected and included in the database for future uses. In order to assess the occurrences of potential emerging contaminants in drinking water, water samples which included raw water and finished water were taken from 7 selected water treatment plants include Chang-Xing, Ban-Xin, Xin-Shan, Feng-Yuan, Xiao-Ping, Cheng-Chin-Hu and Tai-Hu. In addition, samples were taken from each treatment unit of two water treatment plants for analysis to assess the treatment efficiencies of these compounds after conventional treatment processes. The results showed that acephate, temephos, cartap, phosmet, pendimethalin triclosan, and 1,4-dioxane were not detected in raw water and finished water. The results also showed that emerging disinfection byprodusts have higher detection rates in finished water at trace leves (dichloroacetonitrile were ND-5.87 g/L; bromochloroacetonitrile were ND-9.58 g/L; dibromoacetonitrile were ND -7.74 g/L; 1,1-dichloro-2-propanone were ND -1.27 g/L; 1,1,1-trichloro-2-propanone were ND -2.76 g/L; and chloral hydrate were ND -18.76 g/L). The detection rates of galaxolide and tonalide were about 50% in raw or finished water with very low levels (ng/L). The results also showed that the conventional water treatment processes could remove carbendazim, the detectable concentrations in treated water were lower than those in raw water. During the study, three Advisory Panel Meetings were called and several related subjects were discussed. The valuable comments from panelists were considered and adopted when possible to improve the quality of this study. Based on the results of this study, the panelists also approved that dichloroacetonitrile, bromochloroacetonitrile, dibromoacetonitrile, 1,1-dichloro-2-propanone, 1,1,1-trichloro-2-propanone, and chloral hydrate may be included in the watch list of the contaminant candidates for further evaluation. Since galaxolide is widely used, it is necessary to establish the standard analytical method and collection of more environmental data is recommended. The chemicals included in the watch list were considered necessary for additional monitoring and assessment for their occurrences in drinking water and potential health effect.
Keyword
Contaminant candidates, drinking water quality standards, health risk assessment, emerging contaminants, emerging disinfection byproducts;Contaminant candidates, drinking water quality standards, health risk assessment, emerging contaminants, emerging disinfection byproducts
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