A study on the concentration and health risk of trihalomethanes in drinking water

Chung, Yong; Shin, Dong Chun; Lee, Bo Young; Yu, Sung Han; Chung, Sang Hyuk

Abstract

This study was conducted as a nationwide survey in Korea to determine the THM (trihalomethane) concentration levels in the drinking water of 14 selected cities. The survey was undertaken in one city (Kwangju) during September and October of 1988 and 14 cities in January through February of 1988. The results were as follows: 1. The KMnO4 consumption was 10.6 mg/l - 11.6 mg/l in Pusan and Ulsan, exceeding the drinking water standard of 10 mg/l. Pusan, Inchon, Kwangju, Ulsan, Mokpo and Junju areas also exceeded the ammonia nitrate standard of 0.5 mg/l, Other tap waters surveyed were detected below the drinking water standards. 2. The THM concentrations of tap water measured in January and February of 1989 were detected in the range 1.20 microgram/l - 150.8 microgram/l. 3. In the comparative study of the THM concentration of tap water measured in the Kwangju area during September and October of 1988, the average THM concentration of 145.63 +/- 70.72 microgram/l showed a sifford increase compared to that of 23.8 +/- 8.31 microgram/l surveyed in January and February 1989. 4. The proportion of the four THM compounds found in tap water was bromoform, 47%; chloroform, 30%; chlordibromomethane, 13%; and dichlorobromomethane, 10%. 5. Since the results indicate that the concentration of bromoform was 2 - 10 times higher than that of chloroform measured in the seaside district of Pusan, Ulsan and Cheju Island, it is reasonable to assume that the raw water was somehow influenced by seawater. 6. The average lifetime cancer rate of the population exposed to chloroform measured in the surveyed areas was 17 cancer incidences per 1 million population. From the above results, the existence of THM in the distribution systems seems to be inevitable, since chlorine disinfection is performed in water treatment plants in our country. There seems to be a trend of increasing. THM concentrations due to the contamination of raw water. In order to establish any form of regulations, health risk assessment is an imminent subject.