Determining risk No easy task

This story appeared in the Antelope Valley Press January 14, 2001

By BRENDA ZAHN
Valley Press Staff Writer

LANCASTER - The scare over the carcinogen chromium 6 has alerted the public to the fact that the science of health risk assessment is far from perfect.

It's an ever-changing process that leaves much room for speculation.

Recent testing of 110 county facilities showed elevated levels of chromium 6 at several county sites. A second round of tests on 44 Antelope Valley-area water wells found that 32 of the wells have levels of chromium 6 ranging from 2.8 parts per billion to 17.6 ppb.

Although there is no formal state or federal standard for chromium 6, the state-mandated maximum safe level for total chromium is 50 ppb. The federal standard for total chromium is 100 ppb.

The state Office of Environmental Health Hazard Assessment has recommended a public health goal for total chromium of 2.5 ppb, and 0.2 ppb for chromium 6.

The inconsistency in standards has the public confused and worried.

"It's a huge guessing game," local environmentalist Jane Williams said.

Scientists often evaluate risks by testing chemicals on rats or monkeys, Williams said, but they can't test dangerous chemicals on humans. Therefore, they have to take their animal test information and use various formulas to parlay those results into reasonable standards for human consumption.

As scientists struggle to define the risk of the contaminants they know exist, the problem becomes bigger as companies use more and more chemicals in their operations, said Marguerite Young, California director of the national environmental organization Clean Water Action.

"If we start looking for some of these chemicals that are in use in our society ... chances are pretty good that we're going to find them," Young said. "It should be a symbol to us that we need to take a comprehensive look at how to have a thinking-ahead strategy for drinking water protection."

She said the public's best bet is to study the annual consumer confidence reports sent to them by their water purveyors. Those reports list contaminants in the drinking water.

Take those figures and use your own judgment as to what's safe, she said.

The truth is that the effects from most of the contaminants occur in such a small portion of the population that scientists have a hard time studying enough people to confirm an actual health effect, Young said.

When they determine that there's a health risk, officials then have to weigh the extent of the risk against how much money it would take to clean the water.

"Really, it boils down to the same old thing. How much time does it take and how much expense does it take?" Young said. "And then, to prove something, it's never enough to do just one study. You've got to have at least one other study to replicate, or to point in that same direction.

"It may be practically impossible, given the sheer volume of chemicals in use in our society right now, to do that," Young said.

Determining what's safe in the drinking water is an intricate process that takes years, said Bruce Macler, a drinking water toxicologist with the U.S. Environmental Protection Agency. He said the EPA is always gathering new information and updating its standards accordingly.

"It's a public health judgment as to how safe people want water, but if people think it should be safe with respect to chrome, it's fair to balance that with respect to other contaminants," he said. "It is public policy in the end. If folks want water a certain way, then that's fine, but by and large, we try and balance it."

Californians can find some solace in the fact that their drinking water is some of the safest and most strictly regulated in the country, said Greg Dluzak of the Palmdale Water District.

He said the risks of chromium 6 must now be determined based on a limited amount of data that was gathered from mice testing in the 1960s. Such is the dilemma of risk assessment.

Scientists don't even know such simple facts as whether chromium 6 is naturally converted into the nutrient chromium 3 in people's stomachs. Chromium 3 is actually beneficial to the body.

As scientists do their further studies on chromium 6, people should put it all into perspective, Dluzak said.

"You have to use a little bit of logic here. You think about all the things we do in a day and all the chemicals we submit ourselves to," he said. "There is a point where even bad things, at the right amount, are good for you, but at a certain amount they're bad.

"One thing we all have to realize is there is no such thing as zero risk," he said. "If you go to a baseball game, even though they have nets up, that doesn't ensure 100% that you won't get hit by a fly ball or a foul ball."

Dluzak offered one way for people to take control over what goes into their drinking water - make sure not to dump hazardous chemicals themselves.

"People work on their cars, drain the antifreeze out on the ground," he said. If a person sees such behavior, they should report it to the police, he added.