How much of a dangerous chemical is safe to drink?
San Bernardino County Sun, Jason Pesick
Published December 31, 2006
The answer to that question is something two states - California and Massachusetts - don't agree upon. And a new study by scientists at the national Centers for Disease Control and Prevention has put California on the defense for its reliance on an older, smaller-scale study.
The dangerous chemical in question is perchlorate, which has been found in drinking-water wells throughout the Inland Empire, leading Rialto and Colton to file federal lawsuits against a number of corporations and government entities, including Goodrich, Black & Decker, San Bernardino County and, in Rialto's case, the Defense Department.
Used in the production of products such as rocket fuel, explosives and fireworks, perchlorate can be harmful to humans by interfering with the functioning of the thyroid gland.
In July, Massachusetts capped the amount of perchlorate allowed in drinking water at two parts per billion.
California, on the other hand, is heading toward adopting a standard of six parts per billion. That won't become official until the state Department of Health Services responds to comments it received on the plan, which could take until the end of January.
The differences boil down to science and politics, officials and environmentalists say.
Limited study
This summer, before the release of the CDC study, the state Health Services Department proposed six parts per billion as the maximum level of perchlorate allowed in drinking water.
Some environmentalists complained that the level was too high, noting it was three times higher than the level set by Massachusetts only a month earlier.
State officials based their proposal on a study authored by the late Dr. Monte Greer, who reported that healthy adults could safely be exposed to perchlorate at concentrations of about 200 parts per billion.
"We felt that the Greer study was really the best study to use," Allan Hirsch, a spokesman for the California Office of Environmental Health Hazard Assessment, said before the CDC released its study.
The Greer study, however, was limited in scope. It exposed a relatively small number of healthy adults - 37 - to perchlorate for just 14 days.
Because of those limitations, Renee Sharp, an analyst at the Environmental Working Group, a nonprofit environmental research organization, said California should have considered how perchlorate can affect sensitive populations, such as children and people with thyroid conditions.
Massachusetts officials agreed.
Carol Rowan West, director of the Massachusetts Department of Environmental Protection's Office of Research and Standards, put less confidence in the Greer study than do her counterparts in California.
"We had more concerns about the quality of the data and lack of data on certain issues," she said.
In addition, while California officials assumed that 60 percent of the perchlorate a person ingests comes from drinking water, Massachusetts officials put that number at 20 percent, saying people consume more perchlorate from food.
Women and perchlorate
The CDC study provides policymakers with a great deal of new information to chew on.
"It's a very respectable study from a highly respected organization," said Kevin Mayer, the regional perchlorate coordinator for the Environmental Protection Agency.
The nationwide study found that even low levels of perchlorate can affect thyroid hormone levels.
"We didn't expect to see such low levels of perchlorate have this effect on the thyroid," said one of the study's co-authors, James Pirkle.
He said women with low urinary iodine levels or low levels of iodine in their diet are particularly vulnerable.
"This is going to be important information for those people who are setting acceptable levels (for perchlorate)," he said.
The California Office of Environmental Health Hazard Assessment is now analyzing the CDC's data, Hirsch said.
Kevin Riley, the deputy director for prevention services at the California Department of Health Services, said the agency is not legally permitted to set a lower standard than what California Office of Environmental Health Hazard Assessment recommends.
The political factor
Environmentalists also claim that political and cost considerations help explain why California is moving toward a higher standard than the one adopted by Massachusetts.
If the California standard were set at two parts per billion, the costs of treating water would be "astronomical," said Eric Fraser, Colton's director of water and wastewater.
He said water standards are often based on factors other than public health. Water in the Bay Area, for example, is only disinfected, not filtered, he said, because of political pressure to lower water-quality standards.
"It just shows you how the political process sometimes can impact the adoption of drinking- water standards," he said.
