The village currently uses liquid chlorine to disinfect the water and kill microorganisms. Byproducts of chlorination are haloacetic acids (HAA5). A 2004 Environmental Protection Agency law said that water sources can have a maximum of 60 parts per billion microliter of HAA5 in the water supply and still be considered safe. McKenzie Pond was found to have 61.1ppb MCL in March. That level has since fallen to 58.8ppb MCL for June.
Because of the one-time violation, the village will now have to either filter its water or find another water source within 18 months of the department’s final decision.
Currently, the Village chlorinates its water to kill microorganisms. The problem with this is that the chlorination process can result in the formation of haloacetic acids when the chlorine reacts with organic materials found in unfiltered water. This is also called formation of disinfection by-products (DBP). Haloacetic acids are a group of chemical compounds based on the acetic acid molecule (CH3COOH) where one or more hydrogen atoms attached to carbon atoms are replaced by a halogen (chlorine).
Although the EPA sets very stringent allowable levels of HAA's there really is not much evidence that HAA's pose a significant risk. There is evidence in mice and rats and in in vitro studies that exposure to HAA causes increased risk of problems in embryos. But this recent study on pregnancy loss finds no correlation between pregnancy loss and DBP exposure (including HAA). Here is another finding that HAA exposure does not result in significantly increased preterm births. A long term study on the effects of HAA exposure on the incidence of leukemia has recently been reported. The incidence of chronic myloid leukemia increased in those with high exposure to HAA. But the incidence of other leukemias actually went down.
All this being said, I am surprised that the Village does not filter its water. There is nothing more important than a safe, clean and pure water supply except perhaps an effective sewage system in protecting a population from disease.
An exposure summary of HAA's can be found here. HAA exposure of 70 ppb results in a 1:10,000 risk of getting cancer during ones lifetime.
A classification and assessment of HAA can be found here.