“Expectant mothers can expose themselves to the higher risk by drinking the water, swimming in chlorinated water, taking a bath or shower, or even by standing close to a boiling kettle, say researchers.

The finding, based on an analysis of nearly 400,000 infants, is the first that links by-products of water chlorination – chemicals known as trihalomethanes, or THMs – to three specific birth defects.

Exposure to high levels of THMs substantially increased the risk of holes in the heart, cleft palate and anencephalus, which results in the absence of a major portion of the brain, skull, and scalp.” ( source )

Most water systems chlorinate the water they provide in an effort to eliminate parasites and bacteria in drinking water which could lead to waterborne ailments and illnesses.

Not sure if your water contains THMs? Maybe the next few statements will help:

• Public water supplies that use free chlorine as their primary disinfectant (instead of chloramines) may contain THMs. The compounds form when free chlorine molecules lock horns with a biological contaminant during the disinfection process.
• Public water supplies that use chloramines as their primary disinfectant (instead of free chlorine) typically do not contain THMs. However it should be noted that these water systems do periodically ‘burn’ their water lines with free chlorine in an effort to get rid of any biofilm that has formed and THMs do result from those ‘burn’ sessions.

Still unsure as to whether or not your drinking water may contain THMs? You have three options:

1. Call your local water authority and ask them if they use free chlorine as the primary disinfectant or chloramines. If so, then your water most likely contains chloramines.
2. Have your water tested by a certified water testing professional.
3. Use reliable drinking water test kits for both free chlorine AND total chlorine.

Byproducts of the chemical reaction between the ‘bad’ components and the oxidizers form each time one of those ‘bad’ components gets eliminated and we call the disinfection byproducts. See below for a list of the ones listed in the National Primary Drinking Water Regulations for Disinfection ByProducts along with their MCL’s (Maximum Contaminat Levels) and potential hazards to humans:

• Bromate — Associated with an increased risk of cancer. Maximum Contaminant Level: 0.01 mg/L
• Chlorite — Associated with Anemia; infants and young children: nervous system effects. Maximum Contaminant Level: 1.0 mg/L
• Haloacetic acids (HAA5) — Associated with an increased risk of cancer. Maximum Contaminant Level: 0.06 mg/L
• Total Trihalomethanes (TTHMs) — Associated with liver, kidney or central nervous system problems; increased risk of cancer. Maximum Contaminant Level: 0.08 mg/L