Illinois-Indiana Sea Grant says that the disinfection of drinking water has virtually eliminated water-borne illnesses in much of the world but that the disinfecting process has lead to its own set of concerns.

According to a statement released on Monday, some disinfectant by-products, or DBPs—created by the reaction of organic water with the disinfectants—can have long-term health impacts, including several types of cancer. Some DBPs have been linked to fetal development problems.

“Approximately 600 DBPs have been identified, which represents only a fraction of the total number,” said Michael Plewa, a genetic toxicologist at the University of Illinois. At the moment, however, the U.S. Environmental Protection Agency (EPA) regulates only a small number of DBPs, although the agency is in a multi-year period of evaluation of the new Stage 2 Drinking Water Disinfection Rule.

In a project partially funded by Illinois-Indiana Sea Grant, Plewa has developed a comprehensive in vitro database of toxicity levels of DBPs considered a priority by the U.S. EPA. Plewa’s team, which included EPA scientists, test DBPs to assess their impact on mammal cells and their genetic material.

“Michael Plewa’s database will provide important data to aid in the EPA’s assessment of present regulations,” said U.S. EPA scientist Susan Richardson. “The database can also serve as a much-needed practical resource for the water treatment community as they make decisions regarding local disinfection practices.”

For example, the statement said, to reduce the occurrence of regulated by-products, some communities have switched from chlorine to chloramine in their disinfection process. “In water that is high in organic matter, typically surface water, this can lead to an increase in emerging classes of nitrogen-containing DBPs, some of which Plewa has found to be considerably more toxic than those that are regulated. In water that contains iodine, such as water that has been infiltrated with sea water or sea water that has been locked away underground, the use of chloramine can produce highly toxic iodinated DBPs.”

“Some iodinated DBPs are the most genotoxic to mammalian cells of any known DBPs.” said Plewa. “Water managers should know that the spectrum of DBPs shifts when chlorine is replaced with chloramine.”

Plewa is not recommending that people steer clear of tap water, the statement said, and in fact he called the disinfection of drinking water the most important public health event of the 20th century. “And tap water, unlike bottled water, is regulated,” he said. “But, for those concerned about DBPs, its a good idea to use a point-of-use filter in their home.”

Plewa did note that one day, through genetic testing, it may be possible to pinpoint people particularly vulnerable to health problems related to DBPs and to make appropriate recommendations.”

The Illinois-Indiana Sea Grant College Program is one of 30 National Sea Grant College programs. Created by Congress in 1966, Sea Grant combines university, government, business, and industry expertise to address coastal and Great Lakes needs. Funding is provided by the U.S. Department of Commerce, the National Oceanic Atmospheric Administration, the University of Illinois, and Purdue University.

Posted 4/8/2008