Abstract

Chlorine is widely used in the disinfection process of water supply systems to eliminate pathogens. However, a complication that occurs during the disinfection process is the formation of by-products that include volatile organic compounds such as chloroform and other trihalomethanes. This study is intended to assess the risk of trihalomethanes in tap water. Water samples were taken from end-user tap water near wastewater treatment plants in various locations in Perlis, Malaysia. Following the standard procedure and calculation method proposed by the US EPA, the exposure dose (mg/kg day)) for oral ingestion, dermal absorption and inhalation was calculated. A total of 90 independent data were obtained from the Perlis regions. Risk assessments were calculated and three groups were formed to represent three separate waste water treatment plants. The assessment of cancer risk in the Timah Tasoh area by ingestion routes for dibromochloromethane, bromo-dichloromethane and chloroform was 3.04 × 10^–5, 1.73 × 10^–4, and 2.67 × 10^–5, while for the dermal pathway it was 6.65 × 10^–4, 3.97 × 10^–4, and 7.19 × 10^–5 and inhalation for dibromochloromethane, bromodichloromethane, bromoform and chloroform—1.33 × 10^–3, 1.02 × 10^–3, 1.38 × 10^–3, and 6.32 × 10^–5. Another study area, Kuala Sungai Baru, has the lowest trihalomethane content. Obviously, the lowest risk as some of the compounds were found to be below the US EPA limit. The combined risk of cancer in these three study areas for the ingestion method was 1.23 × 10^–5, 1.07 × 10^–4, and 1.11 × 10^–5. The results showed that the carcinogenic risk assessed for chloroform, bromodichloromethane and dibromochloromethane was within the established limit in some areas, but exceeded the acceptable level in other areas of the study. In addition, the greatest risk from trihalomethanes appears to arise from inhalation followed by ingestion and skin contact. This study made the Perlis Exploration Area Warning as a reference point for other nearby areas.

中文翻译：

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饮用水供应中三卤甲烷的潜在风险评估

摘要

氯气广泛用于供水系统的消毒过程，以消除病原体。然而，在消毒过程中发生的并发症是副产物的形成，其中包括挥发性有机化合物，例如氯仿和其他三卤甲烷。本研究旨在评估自来水中三卤甲烷的风险。水样取自马来西亚玻璃市不同地点的污水处理厂附近的最终用户自来水。按照美国环保署提出的标准程序和计算方法，计算了口服摄入、皮肤吸收和吸入的暴露剂量（mg/kg·天）。从玻璃市地区获得了总共 90 个独立数据。计算了风险评估，并形成了三个组来代表三个独立的废水处理厂。^–5、1.73 × 10 ^–4和 2.67 × 10 ^–5，而对于真皮途径，它是 6.65 × 10 ^–4、3.97 × 10 ^–4和 7.19 × 10 ^–5和吸入二溴氯甲烷、溴二氯甲烷、溴仿和氯仿—1.33 × 10 ^–3、1.02 × 10 ^–3、1.38 × 10 ^–3和 6.32 × 10 ^–5。另一个研究区，Kuala Sungai Baru，三卤甲烷含量最低。显然，发现某些化合物的风险最低，低于美国环保署的限制。摄入方法在这三个研究领域的综合癌症风险为 1.23 × 10 ^–5 , 1.07 × 10 ^–4和 1.11 × 10 ^–5。结果显示，氯仿、溴二氯甲烷和二溴氯甲烷的致癌风险评估在某些地区处于既定限度内，但在研究的其他领域超过了可接受的水平。此外，三卤甲烷的最大风险似乎来自吸入，然后是摄入和皮肤接触。这项研究将玻璃市勘探区警告作为附近其他地区的参考点。