Panyakapo Mallika, Soontornchai Sarisak, Paopuree Pongsri
Department of Environmental Science, Faculty of Science, Silpakorn University, Nakhon Pathom 73000, Thailand.
J Environ Sci (China). 2008;20(3):372-8. doi: 10.1016/s1001-0742(08)60058-3.
We investigated the concentration of trihalomethanes (THMs) in tap water and swimming pool water in the area of the Nakhon Pathom Municipality during the period April 2005-March 2006. The concentrations of total THMs, chloroform, bromodichloromethane, dibromochloromethane and bromoform in tap water were 12.70-41.74, 6.72-29.19, 1.12-11.75, 0.63-3.55 and 0.08-3.40 microg/L, respectively, whereas those in swimming pool water were 26.15-65.09, 9.50-36.97, 8.90-18.01, 5.19-22.78 and ND-6.56 microg/L, respectively. It implied that the concentration of THMs in swimming pool water was higher than those in tap water, particularly, brominated-THMs. Both tap water and swimming pool water contained concentrations of total THMs below the standards of the World Health Organization (WHO), European Union (EU) and the United States Environmental Protection Agency (USEPA) phase I, but 1 out of 60 tap water samples and 60 out of 72 swimming pool water samples contained those over the Standard of the USEPA phase II. From the two cases of cancer risk assessment including Case I Non-Swimmer and Case II Swimmer, assessment of cancer risk of non-swimmers from exposure to THMs at the highest and the average concentrations was 4.43 x 10(-5) and 2.19 x 10(-5), respectively, which can be classified as acceptable risk according to the Standard of USEPA. Assessment of cancer risk of swimmers from exposure to THMs at the highest and the average concentrations was 1.47 x 10(-3) and 7.99 x 10(-4), respectively, which can be classified as unacceptable risk and needs to be improved. Risk of THMs exposure from swimming was 93.9%-94.2% of the total risk. Cancer risk of THMs concluded from various routes in descending order was: skin exposure while swimming, gastro-intestinal exposure from tap water intake, and skin exposure to tap water and gastro-intestinal exposure while swimming. Cancer risk from skin exposure while swimming was 94.18% of the total cancer risk.
我们调查了2005年4月至2006年3月期间佛统府地区自来水和游泳池水中三卤甲烷（THMs）的浓度。自来水中总三卤甲烷、氯仿、溴二氯甲烷、二溴一氯甲烷和溴仿的浓度分别为12.70 - 41.74、6.72 - 29.19、1.12 - 11.75、0.63 - 3.55和0.08 - 3.40微克/升，而游泳池水中的浓度分别为26.15 - 65.09、9.50 - 36.97、8.90 - 18.01、5.19 - 22.78和未检出 - 6.56微克/升。这表明游泳池水中三卤甲烷的浓度高于自来水，特别是溴化三卤甲烷。自来水和游泳池水中总三卤甲烷的浓度均低于世界卫生组织（WHO）、欧盟（EU）和美国环境保护局（USEPA）第一阶段的标准，但60份自来水样本中有1份、72份游泳池水样本中有60份的浓度超过了USEPA第二阶段的标准。在两种癌症风险评估案例中，包括案例一非游泳者和案例二游泳者，非游泳者在最高浓度和平均浓度下接触三卤甲烷的癌症风险评估分别为4.43×10⁻⁵和2.19×10⁻⁵，根据USEPA标准可归类为可接受风险。游泳者在最高浓度和平均浓度下接触三卤甲烷的癌症风险评估分别为1.47×10⁻³和7.99×10⁻⁴，可归类为不可接受风险，需要改善。游泳导致的三卤甲烷接触风险占总风险的93.9% - 94.2%。通过各种途径得出的三卤甲烷癌症风险从高到低依次为：游泳时皮肤接触、饮用自来水时胃肠道接触、皮肤接触自来水以及游泳时胃肠道接触。游泳时皮肤接触导致的癌症风险占总癌症风险的94.18%。
