Trihalomethanes (Thms) As Percentage of Total Organic Halogen (Tox) at Varying Experimental Conditions



Pourmoghaddas H¹ ; Kinman RN² Show Affiliations
Source: Iranian Journal of Public Health Published:2004

Abstract

Toxicology studies have shown several DBPs including THMs to be carcinogenic or causing adverse reproductive or developmental effects in laboratory animals, numerous epidemiological studies have suggested an increased cancer risk to individuals exposed to chlorinated waters. It has been shown that, regardless of the source, trichloromethane (TCM) comprised approximately 20 percent of the TOX. While there is controversy of the THMs as percentage of TOX, in an extensive study, effects of 3 pH values, 3 reaction times and 4 bromide concentrations on the formation of 4 THMs, trichloromethane (TCM), dicholorobromomethane (DCBM), dibromochloromethane (DBCM) and tribromomethane (TBM) as percentage of TOX have been evaluated. Factorial designs were used to statistically evaluate influences of different factors. Honesty Significant Differences test (HSD) and ANOVA tests were used for the statistical analyses. The Excel graphic software was used for plotting the formation curves, and Lotus 1, 2, 3 was used for the calculations. Statistical analyses showed that the parameters Br, pH and reaction time had significant effects on the formation of TOX and individual THMs. The study revealed that although TCM was the principal percentage of the TOX as THMs in the absence of bromide ion, this compound decreased rapidly with the incremental addition of Br. This study also showed that brominated and mixed species would be dominated in the presence of a high Br concentration which contributes to a high percentage of the TOX. © 2004, Iranian Journal of Public Health. All rights reserved.