Parveen Naseeba, Chowdhury Shamik, Goel Sudha
School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721 302, India.
Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721 302, India.
Environ Sci Pollut Res Int. 2023 Feb;30(10):24793-24803. doi: 10.1007/s11356-021-17087-0. Epub 2021 Oct 27.
Trihalomethanes (THMs) are common disinfection by-products in chlorinated tap waters. They can cause various cancers and non-cancer health hazards. Ingestion, dermal contact, and inhalation are the three exposure routes considered in the THM hazard or risk assessments. Among these, inhalation hazard is generally calculated by assuming the initial concentration as zero. This assumption fails to address the case of continuous or successive showers that can happen in shared showering facilities such as student hostels or gymnasiums. In the present study, the leftover THM concentration from the previous bath was considered to assess the chronic daily intakes (CDI) and hazard index (HI) for successive showers. For this, tap water of a university campus was analyzed to understand the extent of THM exposure at consumer points and the result obtained was used for the hazard assessment. Total THM concentrations varied from 0.51 to 68.9 µg L. To address the variability of the model input parameters, 50,000 iterations of Monte Carlo simulation were carried out. Maximum HI values of 7.94E - 02 ± 3.63E - 02, and 6.69E - 02 ± 3.08E-02 were observed for the 1 shower for females and males, respectively. This value increased exponentially up to the 5 shower and thereafter, the value was constant. The methodology followed in the present study successfully determines the risk and hazard of THMs through successive showers.
三卤甲烷（THMs）是氯化自来水中常见的消毒副产物。它们会引发各种癌症和非癌症健康危害。摄入、皮肤接触和吸入是三卤甲烷危害或风险评估中考虑的三种暴露途径。其中，吸入危害通常通过假设初始浓度为零来计算。这种假设未能考虑到在学生宿舍或体育馆等共享淋浴设施中可能发生的连续或相继淋浴的情况。在本研究中，考虑了前一次沐浴后残留的三卤甲烷浓度，以评估连续淋浴的慢性每日摄入量（CDI）和危害指数（HI）。为此，对某大学校园的自来水进行了分析，以了解消费者端三卤甲烷的暴露程度，并将所得结果用于危害评估。三卤甲烷的总浓度在0.51至68.9微克/升之间变化。为了解决模型输入参数的变异性问题，进行了50000次蒙特卡洛模拟迭代。女性和男性单次淋浴的最大HI值分别为7.94E - 02 ± 3.63E - 02和6.69E - 02 ± 3.08E - 02。该值在第5次淋浴前呈指数增长，此后保持恒定。本研究采用的方法成功地确定了连续淋浴过程中三卤甲烷的风险和危害。
