The agency that serves much of the drinking water to 18 million Southern Californians will start adding fluoride to its supply beginning in late October at a treatment plant that provides water to most of western Riverside County.
Although state and county health officials said Friday that fluoride is considered beneficial to prevent tooth decay, an environmental group said new research has raised questions about possible health risks associated with fluoridated water since Metropolitan Water District approved the move in 2003.
“All we’re trying to say is look, things have completely changed since you made your decision, you have an obligation to consider this new evidence,” said Bill Walker, vice president of the Oakland-based Environmental Working Group.
The group will hold a news conference Monday in downtown Los Angeles to raise its concerns before an MWD committee is briefed on the issue by Kathleen Thiessen. She co-authored a study issued in March 2006 by the National Research Council that concluded that a federal standard twice as high as California’s should be lowered because infants and young children can be exposed to three to four times as much fluoride as adults due to their lower body weight.
The report said that evidence to date regarding fluoride’s potential to cause cancer, particularly of the bone, is tentative and mixed.
David Nelson, a consultant to the state’s Office of Oral Health under the California Department of Public Health, will also brief the MWD committee. He said California’s maximum for fluoride in drinking water is 2 parts per million. The recommended level for Southern California, he said, is 0.8 parts per million, the level to which MWD will raise its fluoride.
Nelson said the recommended levels for adding fluoride to water are based on temperature. With warm temperatures in Southern California, he said, people tend to drink more water than in cooler regions of the nation where the recommended level would be higher.
Walker said he is concerned about the impact on young children. The American Dental Association last November suggested that parents of infants who are fed formula use nonfluoridated water to mix it.
Typically, formula already contains fluoride, said Dr. Margaret Beed, San Bernardino County health officer. She said parents should use bottled water that doesn’t contain fluoride.
Water districts and city utilities with more than 10,000 connections have been required to add fluoride to their water since a 1995 state law went into effect. MWD, as a wholesaler, was not part of that.
MWD’s board approved the addition of fluoride to its water after health officers from the six Southern California counties it serves asked them to do so, said Edgar G. Dymally, the water district’s senior environmental specialist.
“There’s no question if you were to ask any health officer of the benefits to adding fluoride to drinking water to prevent tooth decay, we see that as a benefit and we support that,” said Dr. David Herfindahl, Riverside County’s deputy health officer.
Fluoride will be added to the water at the Henry J. Mills Filtration Plant in Riverside’s Mission Grove area Oct. 29, said Denis Wolcott, an MWD spokesman. After that, over the next few weeks, it will be added to the agency’s four other treatment plants, including the one at Lake Skinner, near Temecula.
Although Chino-based Inland Empire Utilities Agency is an MWD member, it is served untreated water, Wolcott said.
Some Inland cities like Riverside and San Bernardino use little to no MWD water. One of the region’s most-tapped aquifers, the Bunker Hill basin below the San Bernardino Valley, already has enough naturally occurring fluoride caused by soil erosion that none has to be added, said Kevin Milligan, assistant director for water at Riverside Public Utilities.