My recent news story about a study that finds no developmental or reproductive effects in lab rats from drinking tap water might give people a sigh of relief. Yet the verdict is definitely still out on this topic.
As I describe in Chemical & Engineering News, the latest published research from a long-term multi-lab study sponsored by the EPA examines the potential human health effects associated with exposure to by-product chemicals created during the water-disinfection process. These disinfection by-products are known as DBPs.
A big question posed in this study is whether long-term exposure to DBPs might cause rats to lose their pups before giving birth–analogous to spontaneous abortion in humans–or give birth to pups with low birth weight. The team didn’t find these reproductive effects but they did find very slight effects on delayed puberty in females and reduced sperm counts in adult male rats.
Research findings that show drinking water might cause reproductive effects in humans are still very much in debate. Another study I wrote about last year took a careful look at whether drinking water DBPs might damage cells and genes. The study’s preliminary result was that the DBPs might be a contributor to negative pregnancy outcomes, such as low birth weight.
Researchers also are looking into the health effects of chlorinated water in swimming pools. Yet all of these studies are complicated: for one reason, waters contain various pollutants (think pharmaceuticals, pesticides and organic matter), and each different disinfection method produces its own suite of DBPs in the water.
With all of this conflicting information, it’s important to remember that the processes used to disinfect drinking water (and there are several) have saved thousands of lives by controlling such water-borne diseases as dysentery, cholera, and typhoid fever. Disinfectants also significantly reduce our suffering by killing bacteria and viruses.
For more information about disinfection by-product research, check out this summary of the EPA’s Four Lab Study experiments.
Photo: Lisa Burke