Evaluating Trihalomethane content in drinking water on the basis of common monitoring parameters: regression models.* Trihalomethanes (THMs) are compounds derived from methane that incorporate three halogenated halogenated pertaining to a substance to which a halogen is added. halogenated salicylanilides see rafoxanide, clioxanide. atoms. * THMs can form during chlorination chlorination Public health Addition of chlorinated compounds to drinking water as disinfectants. Cf Ozonation. of drinking water drinking water supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. . * These compounds have diverse negative effects on environmental and human health, including --toxicological effects, --mutagenic effects, --carcinogenic effects, --induction of congenital malformations, and --retarded fetal growth. * Chloroform chloroform (klôr`əfôrm) or trichloromethane (trī'klôrōmĕth`ān), CHCl3 and methylene chloride are the major THM byproducts of chlorination. * The level of THMs in drinking water should be evaluated periodically. * It would be useful to know which of the already habitually monitored variables could also serve as an indicator for THMs. * This study undertook to examine the relationship between THMs and the parameters more commonly determined in the control of chlorinated chlorinated /chlo·ri·nat·ed/ (klor´i-nat?ed) treated or charged with chlorine. chlorinated charged with chlorine. chlorinated acids some, e.g. water. * In the drinking water of Granada, Spain, THMs were detected in untreated water at a mean concentration of 149 micrograms per liter (149 [micro]g/L). * This value increased following chlorination treatment. * pH did not significantly correlate with THM levels. * THMs decreased as the concentration of free residual chlorine increased. * No statistically significant regression was obtained for chlorophyll. * No correlation was found between THM concentration and the microbiological or chemical indicators of fecal contamination. * A correlation was found between THMs and combined residual chlorine. * Combined residual chlorine indicates the presence of organic substances that have not been completely oxidized oxidized having been modified by the process of oxidation. oxidized cellulose see absorbable cellulose. by chlorine. * THM content is related to the presence of organic substances such as humic hu·mic adj. Of, relating to, or derived from humus. Adj. 1. humic - of or relating to or derived from humus; "humic acid" and fulvic acids in water, which are generally derived from sediment runoff. * This fact could also explain the significant relation between nitrates and THMs. * The regression analysis In statistics, a mathematical method of modeling the relationships among three or more variables. It is used to predict the value of one variable given the values of the others. For example, a model might estimate sales based on age and gender. found that the following combinations of parameters adequately identify THM levels: --combined residual chlorine, nitrites, and nitrates; --nitrites, nitrates, and ammonia; and --nitrites, nitrates, ammonia, and chemical oxygen demand. * The level of significance increases with the number of variables taken into consideration. |
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