Local Agencies Say Drinking Water Is Safe

Although concerned about a new study showing a link between chlorinated water and miscarriages, Ventura County public health officials plan to wait until further studies are conducted before issuing a warning to pregnant women.

Meanwhile, local water agencies said there is no reason for residents to be concerned.

According to a study recently completed by researchers at the state Department of Health Services, drinking five or more glasses of cold chlorinated tap water a day may increase the risk of miscarriage to women in their first trimester.

“This is really the first we’ve heard about it and it’s certainly something we want to find out more about before we issue any warnings,” said Diane Visencio, the county’s director of maternal and child health.

The study, which has not yet been released, concerns a chemical compound known as trihalomethanes, or THMs--a common contaminant in chlorinated water.

THMs form when the chlorine--used to kill microorganisms like cholera, typhoid and giardia--reacts with the acid of organic plant material naturally found in water.

The study, which focused on 5,144 pregnant women, found that those who drank more than five glasses of chlorinated tap water a day had a 15.7% risk of miscarriage compared with a 9.7% risk for women who drank less.

The study sampled water that contained more than 75 parts per billion of the compound which, according to most water agencies, is abnormally high. The federal limit on THMs is 100 parts per billion.

While the study has caused alarm among residents from Orange to San Luis Obispo counties, Ventura County water suppliers said there is little if anything to fear when drawing a glass of water out of the tap.

Donald Kendall, general manager of the Calleguas Municipal Water District, said levels of THMs, which were measured late last year at an average of 61 parts per billion, are negligible and cautioned residents from reading too much into the study. The district supplies more than 500,000 county residents from Thousand Oaks to Oxnard.

“We believe it’s premature to reach the conclusion that the region’s water supply is unsafe for any segment of the population given that very few have had time to review the findings of the study,” he said. “But I can say that our water is safe to drink and there’s nothing for people to be concerned with.”

Several years ago the Metropolitan Water District began disinfecting water with chloramines, a chemical that does not break down to form potentially harmful compounds like trihalomethanes.

Metropolitan’s water is then treated again by Calleguas with ozone, which does not contaminate the supply with potentially harmful compounds.

“For me, THMs are a nonissue and they shouldn’t be an issue for Ventura County residents either,” Kendall said. “The levels [researchers] studied are much higher than we’ve ever found in our supply.”

The Oxnard city water department blends water supplied from Calleguas with chlorinated well water.

Ben Wong, water resource manager for the city, also defended the supply, citing tests conducted last December that showed THM levels holding at between 44 and 58 parts per billion.

“THMs aren’t something we’re worried about because all the tests we’ve done over the years never showed it to be a problem,” he said.

Oxnard, however, has begun a project that will change its well-water purification system from chlorine to chloramine by the end of the year.

The Ventura city water department, which supplies 27,000 homes, relies on chlorine to purify the water and has also measured modest THM levels in recent years.

The most recent test, conducted last month, found THM at levels between 50 to 60 parts per billion.

“My best advice is that if you’re pregnant and you’re worried go see a doctor,” Kendall said.