Water Disinfectants & disinfectant by-products

4. Have disinfectants and their by-products affected human health?

• 4.1 Has water disinfection caused cardiovascular disease or cancer?
• 4.2 Has water disinfection harmed pregnancies?

4.1 Has water disinfection caused cardiovascular disease or cancer?

There are no indications that chlorinated or chloraminated drinking-water are a cause of cardiovascular disease in humans. Studies on other disinfectants have not been performed.

Many epidemiological studies have been carried out on the possibility that chlorinated drinking water, and to a lesser extent chloramination, could contribute to cancer in human populations. There have been weak indications that the consumption of chlorinated drinking water may have increased the number of cancers of the bladder, rectum and colon in some studies. However, because the exposure to water contaminants was generally not adequately evaluated, there is no sufficient evidence to say that chlorinated drinking water was or was not the cause of these cancers. It is possible that the associations observed might be due to some other factors.

There are no epidemiological studies on the carcinogenic effects of other disinfectants. More...

4.2 Has water disinfection harmed pregnancies?

Some studies of populations having consumed chlorinated water, have found small to moderate increased risks for some adverse birth outcomes such as miscarriage and neural tube defects. However, these studies are difficult to interpret because of methodological limitations or suspected bias and they need to be confirmed by other studies.

The experts concluded that the results of currently published studies do not provide convincing evidence that chlorinated water or THMs cause adverse pregnancy outcomes. More...