Total trihalomethane

Total Trihalomethanes none 0.10 Liver, kidney or central nervous Byproduct of drinking water disinfection... 

Organic Chemicals Other Than Total Trihalomethanes, Sampling and Analytical Requirements Yes 40 CFR 141.24 EPA 1975... 

The EPA sets rules for the amount of chloroform allowed in water. The EPA limit for total trihalomethanes, a class of chemicals that includes chloroform, in drinking water is 100 micrograms per liter (pg/L, 1 pg/L = 1 ppb in water). Furthermore, EPA requires that spills of 10 pounds or more of chloroform into the environment be reported to the National Response Center. 

Rroposed Rule Total Trihalomethane Sampling and Analysis Yes 58 FR 65622 40 CFR 141.30 ERA 1993c... 

HI Maximum organic contaminant level Total trihalomethane (TTHM) (TTHM = the sum of the concentration of bromodichloromethane, dibromochloromethane and chloroform) Fresh water Salt water Fish consumption Acute 9,600 jjglL ns 5.1 Chronic ns ns ... 

The trihalomethanes (THM) standard is a measurement of total trihalomethanes for a 4-quarter running annual average, based on average values throughout the distribution system. 

The primary drinking water regulations provide an MCL of 0.10 mg L-1 for total trihalomethanes. Recently, public water suppliers have switched from the use of chlorine as a water disinfectant to the use of chloroammines. The latter limits the formation of trihalomethanes, but it could be very toxic to aquatic organisms. 

The US EPA has set a federal drinking water standard (called maximum contaminant level, or MCE) of 100 pgH for total trihalomethanes (a class of drinking water disinfectant by-products). 

Trihalomethane MCL in drinking water is regulated by EPA under the Safe Drinking Water Act)60 EPA does not set limits on the individual THMs (chloroform, bromoform, bromodichloromethane, and chlorodi-bromomethane), but limits the total trihalomethane (TTHM) concentration to 100 ppb. In the 1990s it was found that drinking water contaminated with TTHMs at concentrations below the EPA allowable MCL of 100 ppb... 

Bromodichloromethane Dibromochloromethane Total trihalomethanes Formaldehyde m-Dichlorobenzene Dichloroiodomethane Vinyl chloride Bromodichloroacetic acid Chlorodibromoacetic acid Tribromoacetic acid... 

Total trihalomethanes Carbon tetrachloride Vinyl chloride para- Diehl oroben ze ne... 

Total trihalomethanes (TTHM) Possible cancer risk 0.1-0 Chloroform, drinking water chlorination byproduct... 

For each of the following arsenic, total trihalomethanes, turbidity, and lead, answer these questions Define the measuring unit used for each. What is the allowable level of each What are some of the adverse effects of high levels of these contaminants How do these get into the water supply What is the level in your water supply Even if one of these is not found in your drinking water, you must answer all but the last question for each contaminant. 

ABSTRACT In the definition of safety states of water supply system the quality of drinking water plays an important role. Especially, trihalomethanes as disinfection by-products have to be taken into consideration, because they are dangerous for consumer s health and their concentration usually increase in water distribution subsystem. In this paper the method of determining the thresholds for water quality states (included in the comprehensive method of safety analysis) is presented. The states are based on chloroform because its share in total trihalomethanes is about 80%. Using the tools of mathematical statistics the relationships between chloroform and other quality and operational parameters of drinking water were analyzed and applied to an estimation of quality states. Additionally, the estimation of quality states was based on chloroform in drinking water flowing out from water treatment plant to water pipe network. The study was based on data obtained from the real water supply system. 

Figure 1. Relation between concentrations of total trihalomethanes and chloroform at network points (upper graph) and at water treatment plant (lower graph).

Maximal allowable concentration of total trihalomethanes, established in Drinking Water Directive, is 100 pg/dm The directive does not include allowable concentrations of specified compounds. Polish law imposes additionally the maximal allowable concentration of chloroform (30 pg/dm ). Since the chloroform is about 80% of total trihalomethanes, it is possible that the total trihalomethanes satisfy the norm whereas the maximal allowable concentration of chloroform is exceeded. Therefore the concentration of chloroform is the better quality parameter to be considered in safety models of water supply systems and it is taken as the basic parameter in definitions of quality states in further study. 

Depending on water hardness classes, data given for class 3 (medium hardness), 50 to <100 mg CaCOs/L Total trihalomethanes... 

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