are produced when chlorine, used to disinfect water, mixes with decaying vegetation, he said.
These higher levels also generate significant levels of chlorine by-products (trihalomethanes
and chloramines), which create their own health problems.
Although water disinfecction is essential for reducing the risk of pathogens in the public water supply, potentially harmful disinfection by-products (DBPs) such as trihalomethanes
(THMs) can be formed by the reaction of chlorine and other disinfectants with naturally occurring organic matter and inorganic chemicals in the water.
Two other studies found chloroform, a trihalomethane
, in the blood, urine, and alveolar air of swimmers and attendants at indoor swimming pools (16,17).
This review developed the following data related to typical raw water: turbidity, 1.3 ntu; color, 35 Platinum Cobalt Scale; total trihalomethane
formation potential (TTHMFP), 550 ppb; alkalinity, 10 mg/L; and corrosivity, -2 Langlier Saturation Index.
Currently, the only disinfection by-products regulated are trihalomethanes
. Typical disinfectants are chlorine, chlorine dioxide, chloramines, and ozone.
Inconclusive evidence to date has suggested a potential link between exposure to trihalomethanes
(THMs), a tap water disinfection by-product, and hypospadias, a genital birth defect that affects 70 in 10,000 male births.
Regarding the chlorination by-products problem, it is significant that trihalomethanes
are as high as 0.49 mg/L in the distribution system in some of these communities.
Average exposures to trihalomethanes
(THMs; a surrogate for DBPs) from 15 years of age were estimated based on residential history and information on municipal water sources, and effects of THMs and GSTT1, GSTZ1, and CYP2E1 polymorphisms on bladder cancer were estimated.
In May 2012, for example, chemicals used to treat coal at the Cross Generating Station in Pineville, South Carolina caused an elevated level of carcinogenic trihalomethanes
in the Santee Cooper-Lake Moultrie Public Water System.