press release

February, 1998

FOR IMMEDIATE RELEASE

SWEETWATER AUTHORITY RESPONDS TO STUDY LINKING MISCARRIAGE AND WATER DISINFECTION BYPRODUCTS

A new study by the California Department of Health Services (DHS) has identified possible links between first trimester miscarriage and high levels of Trihalomethanes (THMs) in drinking water. For women who drank more than five glasses of cold tap water with THM levels greater than 75 micrograms per liter, the study found that miscarriages occurred at a rate of 15.7 percent, compared to a 9.5 percent rate for women who drank less than five glasses of water with elevated THM levels, or women whose tap water contained less than 75 micrograms of THMs per liter. 103 women out of more than 5,000 studied were found to meet the criteria for high exposure.

State officials, according to the Sacramento Bee, “were careful to point out that their research contradicts a similar study in North Carolina and that additional research must be conducted by the United States Environmental Protection Agency (EPA) before conclusions are drawn.” Current regulations allow up to 100 micrograms per liter of THMs. Pending regulations may reduce this level to 80 micrograms per liter in the near future.

Trihalomethanes are formed when chlorine, which is used to kill microorganisms in the water, combines with broken-down vegetable matter like weeds or tree roots. There have been concerns about THMs for several years, said Dr. Raymond Nuetra, chief of the CA Division of Environmental and Occupational Disease Control, “because some of these agents at high doses will cause tumors or cancer in mice.”

Sweetwater Authority has responded to prior concerns, and worked to reduce THM levels in several ways. “Our primary concern,” said spokeswoman, “will always be to protect our customers. We are very concerned about the results of this study, and about continuing to provide protection from diseases caused by the bacteria, viruses and similar threats which chlorine eliminates.”

The spokeswoman said her agency would closely follow further studies related to pregnancy outcomes and to determine methods of reducing disinfection side-effects without increased public health risks. She explained that Sweetwater Authority contributes annually to the national American Water Works Research Foundation, and is an active participant in the EPA’s Information Collection Rule (ICR) process. As participants in the process, Sweetwater Athority’s staff will examine the use of enhanced coagulation and Granular Activated Carbon to reduce disinfectant byproducts, including the THMs identified in the DHS study.

The spokeswoman noted that Sweetwater Authority has a long history of working to manage THM levels. The agency renovated its Robert A. Perdue Water Treatment Plant in 1987 to provide chloramine disinfection (using a combination of chlorine and ammonia) which reduced levels of chlorinated byproducts because less chlorine was necessary to provide disinfection. In 1988, a brush removal program was instituted at Sweetwater Reservoir to eliminate plants which would otherwise decay in the water. The first phase of Sweetwater Athority’s Urban Runoff Diversion System was constructed at Sweetwater Reservoir in 1992 to keep the worst quality water out of the reservoir entirely. (A second phase is currently under construction.) The agency has begun work on a Watershed Management Program to further protect water entering its reservoirs from upstream pollution, and is considering a future conversion to ozone disinfection at its Perdue Water Treatment Plant.

The most current THM measurements taken at Perdue Treatment Plant indicated a level of 41 micrograms per liter, well below the level identified in the study. However, she noted that THM levels can vary widely based on the season, rainfall levels, and whether the agency is drawing most of its water from its reservoirs, as opposed to its groundwater and imported water sources. The Department of Health Services is urging pregnant women to continue drinking water, but said those concerned about possible risks can boil their drinking water for two minutes, drink California-certified bottled water (not vending machine type), or use an approved home filtering device (a list is available from CA DHS).

For additional information you may contact:

California Department of Health Services
(510) 450-3818

Metropolitan Water District of Southern California
(213) 217-6485

Association of California Water Agencies
(916) 441-4545

Other:

News Media Reports DHS Study of Water and Miscarriages

THM Questions and Answers

INFORMATION SOURCES
Regarding the California Department of Health Services Study and Trihalomethanes in General

Dr. Raymond Neutra, Division of Environmental and Occupational Disease (CDHS) (510) 450-2400

Shanna Swan, Ph.D., Chief of Reproductive Epidemiology (CDHS) -- study author (510) 540-2669

Christine Arnesen, Chief of Consumer Relations & Training (CDHS) (510) 450-3818

Ken August, Press Office, (CDHS), (916) 657-3064

Water Industry Representatives"

Association of California Water Agencies, Stephen K. Hall, Executive Director
(916) 441-4545

American water Works Association, Jack W. Hoffbuhr, Executive Director
(303) 794-7711

Treatment and Trihalomethanes:

John Gaston, California Water Quality Expert, (510) 251-2426

General:

U.S. EPA Safe Drinking Water Horline: (800) 426-4791

California Department of Health Services: (916) 323-4344

Bottled Water:

DHS Food and Drug Division (916) 229-3125

Certified Home Filtration Devices:

Bob Burns, CDHS, (916) 323-6111