Caution Urged in Reacting to Tap Water Scare

Authors of a study that linked drinking significant amounts of tap water to early miscarriages this week urged caution in interpreting the findings, saying boiling water carries its own risks and is not necessarily “a great choice.”

Kirstin Waller and Shanna H. Swann, the two top state health investigators in the large-scale study of Kaiser patients publicized last week, said the outpouring of concern and some of the recommendations from nonscientists in response to the study went beyond what the study’s researchers know.

In particular, Swann cited the recommendation of Los Angeles Department of Water and Power General Manager S. David Freeman that pregnant women in their first trimester boil tap water for a minute and place it in the refrigerator. Compared to other options, such as using a well-maintained carbon filter, boiling is “not a great choice,” Swann said.

Boiling water is inconvenient and may cause contaminants to be inhaled or become concentrated, they said.

“We had quite a bit of discussion about whether we should include [boiling] at all” as an option, said Waller, the lead author, speaking for the first time in detail about the findings.

The report of the findings, and the response to it, is what some health officials consider a case study in the dilemma of responsibly communicating risk to the public. State officials said they knew that they had potentially important findings but were unsure, and still are, about the full implications.

Freeman insisted that he could not withhold potentially important health information from the public, even if it was incomplete.

Though the study was not published until Wednesday in the scientific journal Epidemiology, water associations and others learned about the basic findings by late January. The Times obtained copies of memos outlining the water associations’ concerns about it and reported the findings last week.

The study found that women who drink five or more glasses of tap water per day containing high levels of common chlorine byproducts--trihalomethanes--were at greater risk of miscarriage in their first trimester than women with less exposure.

The increased risk was noted at concentrations of 75 micrograms per liter or higher. That was an important finding because doctors urge pregnant women to drink lots of water, yet the federal upper limit for trihalomethanes is 100 micrograms per liter (although it will be lowered to 80 in November).

State officials, after much internal discussion, decided against releasing any recommendations based on the study, only the second to look at the link between trihalomethanes and miscarriage and the first to find a potential problem.

Instead, state researchers decided to release a list of “options,” which they said was as far as they felt they could go based on one study that had not been replicated. The other options, besides using water filters and boiling water, were allowing water to stand uncovered for several hours in the refrigerator and drinking bottled water.

“We feel very strongly there is a need to let the public know that the evidence is building, but there is a period of time where their guess is as good as ours as to what to do,” said Raymond Neutra, chief of the division of environmental and occupational disease control for the state health department.

Waller and Swann said they had intended to give water utilities and the media briefings on the study before its publication this week, but word leaked out before then. They said they and the California Department of Health Services were taken by surprise by Freeman’s remarks, which they said were based on secondhand information.

Freeman, who was out of town Wednesday and could not be reached, has said that the public deserved to know as soon as possible about potential risks in drinking water and what to do about them. He noted that although the study was not conducted in Los Angeles--it was based on women served by the Fontana, Santa Clara and Walnut Creek Kaiser facilities--the city’s water often contains more than 75 micrograms per liter of trihalomethanes.

But the researchers--who had agreed with the journal Epidemiology, as is common, not to discuss their findings until they were published--said boiling water creates risks of its own.

They said this week that boiling water is cumbersome and can make water taste bad. A recommendation to boil often leads people to drink less water or something besides water, they said. That is a problem because mothers-to-be need fluids to keep up their blood volume.

In addition, they said, boiling water may cause trihalomethanes to be released into the air, increasing the chances of inhalation.

There is also the possibility that it is not trihalomethanes that are boosting the miscarriage risk. Perhaps it is another byproduct that travels with, or is somehow associated with, trihalomethanes, the researchers said. If that byproduct does not evaporate like trihalomethanes, boiling the water could increase the concentration of the byproduct in the water rather than reduce it.

Finally, they said, boiling water for longer than a minute can lead other metallic and mineral compounds such as lead and salts to become heavily concentrated in the water, presenting an additional risk to consumers.

This week, Swan, Waller and state Department of Health Services officials took pains to explain the quandary they faced in reporting their findings. Though they believed their findings significant, they emphasized that this was only one study, which did not unequivocally point to any safe alternative to tap water consumption.

Refrigeration, for example, will slow down but may not stop formation of trihalomethanes in water, Waller said. The study’s numbers did not warrant a clear recommendation for bottled water consumption, although bottled water is more rigorously regulated in California for trihalomethanes. Even water filters present possible risks if they are not well maintained.

“We face this a lot,” Neutra said. “You need to have the weight of evidence [behind you].”

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Tap Water Findings

The authors of a study linking trihalomethanes, a contaminant often found in tap water, to early miscarriages urge caution in interpreting their findings.

THE STUDY

* examined 5,144 pregnant women between 1989 and 1991 in three california cities. those who drank five or more glasses of tap water per day with at least 75 micrograms per liter of trihalomethanes--121 of the study participants--had an increased risk of miscarriage in their first trimester.

THE REACTION

* Amid an outpouring of concern, researchers said, some public officals and other non-scientists went beyond what the scientists involved know, including stressing that pregnant women in their first trimester should boil tap water for a minute.

RESEARCHERS URGE CAUTION

* The results of the study need to be replicated and should be viewed as preliminary.

* Other options, such as using a carbon filter, may be better than boiling water.