Testing for Trihalomethanes in Your Water (TTHM)
Chlorine has been used to disinfect water for almost a century due to its ability to kill bacteria and viruses in water. The use of chlorine as a disinfectant has been an effective contribution to public health eliminating plagues such as cholera and typhoid, and reducing the incidence of intestinal illness and other health problems caused by waterborne pathogens such as cryptosporidium. The benefits of disinfection, however, do not come without an effect.
Depending on the disinfection procedure used, (chlorination, chloramines, bromine, ozone etc.), and the chemical composition of the water prior to disinfection; many different organic chemical disinfection byproducts can form in drinking water. Trihalomethanes, (THMs), are a byproduct of chlorine disinfection and to a lesser degree, disinfection using chloroamines. The THMs, (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) are formed when free chlorine combines with organic matter, like decaying vegetation commonly found in lakes and reservoirs. Total Trihalomethanes (TTHM) are regulated by the EPA at a maximum allowable annual average of 80 parts per billion. Some of the THMs are very volatile and will vaporize into air easily, so they may be inhaled while showering, however, the EPA has determined that this exposure is minimal compared to that from consumption. The Levels of THMs formed can vary widely on a number of factors including temperature, amount of chlorine used, season, and amount of plant material in the water, among others.
Some drinking water systems use chloroamines as a residual disinfection agent in place of chlorine. Chloroamine is not as reactive as chlorine and less THMs are formed. However, there are also drawbacks to chloroamine use. Chloroamine may cause nitrification and corrosion and may also increase exposure to other disinfection byproducts, such as N-nitrosodimethyl amine (NDMA).
EPA Method 524.2 is used to analyze samples for TTHMs. This method involves concentrating the THMs from a water sample using a technique known as purge and trap. This technique isolates the volatile organic compounds (VOCs) from the water. The VOCs are then desorbed into a gas chromatograph/mass spectrometer (GC/MS) where they are separated, their identity is confirmed, and their concentrations are determined. Standard reporting limits for individual TTH with this method are 0.5 ยต/L
Tags: bromine, chloramines, chlorination, disinfection, EPA, gas chromatograph, GC/MS, NDMA, ozone, public health, THM, Trihalomethanes, TTH, TTHM, VOC
May 28th, 2008 at 11:09 am
I received a letter from my local water company stating that it was in violation of maximum contaminant levels for total trihalomethanes, however my 6 year old daughter has had 3 kidney infections in less than 2 months time. Can this be related to the problem?? And if so how can I avoid the situation?
May 28th, 2008 at 1:32 pm
Hi Christina! Thank you for your question. We believe your inquiry is best suited for a health professional and recommend contacting your doctor or local health department. There is additional information on the EPA’s website which may also help (www.epa.gov).
June 24th, 2008 at 9:16 pm
Will a water softener or a reverse osmosis system with carbon filters help eliminate trihalomethanes in drinking water?
June 25th, 2008 at 8:18 am
Hi Eric! Thank you for your question. Probably the best source for information about water treament options would be the EPA and your State Department of Health. They can tell you which options would best fit your specific situation. Both agencies have websites for more information.
August 11th, 2008 at 10:20 am
I have the same question…the total in our trihalomethanes in town water is 83ppb. I have a reverse osmosis filtration system. Will this clean some of the trihalomethanes out? I didn’t find any resourses to answer this question.
August 11th, 2008 at 3:36 pm
Thank you for your question, Jean. There are many filtration systems on the market which have different capabilities. I would suggest you contact the manufacturer of your system and ask them specifically if their system filters out trihalomethanes (THMs) and under what conditions. If you want to be sure, we can certainly test the water coming out of your system to tell you whether there are still THMs present.
September 18th, 2008 at 7:35 am
I CARRIED OUT AN ANALYSIS FOR SOME WATER FLOWING INTO MY BASEMENT. THE ANALYSIS INDICATED :
DIBROMOCHLOROMETHANE <0.15
DICHLOROBROMOMETHANE <0.13
TRICHLOROMETHANE =0.21
TRIBROMOMETHANE <0.17
THM_TOTAL <1.0
AS I UNDERSTAND ALL THE ABOVE ARE TRIHALOMETHANES WHICH ARE BY PRODUCTS OF CHORINE IN THE PROCESS OF WATER TREATMENT. DOES THE PRESENCE OF THESE CHEMICALS INDICATE THAT THE WATER IS DRINKING WATER ? PRODUCTS OF CH
September 18th, 2008 at 7:39 am
I forgot to indicate that the units of the above are ug/l. I would appreciate your comments
September 18th, 2008 at 9:20 am
The presence of Trichloromethane (chloroform) would probably indicate that the water is tap water. This might help to determine the source of your problem.
September 18th, 2008 at 11:29 am
Thank you for the reply. You are very kind.
Can chloroform be found in nature or is it only found in water that has been treated with chlorine?
September 18th, 2008 at 4:50 pm
Chloroform may be generated by marine algae and in organic-rich spruce forest soil, aided by fugus.