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Narrowing the Universe

There are millions of molecules in our water. Which ones should we worry about?

By Joan Killough-Miller

Inspired by a breaking news story in the early 1980s that revealed a leukemia cluster in Woburn, Mass., Jo Anne Shatkin ’85 was moved to help people understand how environmental threats could affect their well being. Her IQP analyzed the quality of bottled water, using research conducted in the Worcester DPW laboratory of then recent WPI graduate Phil Guerin ’82 (view story).

Shatkin’s commitment to public safety and awareness continues today with her work at Watertown, Mass.–based The Cadmus Group, where she consults with private and government agencies to assess the human health risks of environmental contaminants. Much of her time is spent providing technical support for the EPA’s drinking water Contaminant Candidate List (CCL), to determine which contaminants warrant further study for possible regulation. As an adjunct professor in the Interdisciplinary and Global Studies Division, Shatkin has advised student project work to identify health hazards in the Worcester community.

What is the significance of the CCL?

We’re trying to identify, and narrow the universe of, potential drinking water contaminants. We then decide which ones are the most important for the EPA to invest its resources in. The chemical universe includes hundreds of thousands of manufactured chemicals. We follow a similar process for biological contaminants, working with a team of expert microbiologists to agree upon a methodology for deciding how to effectively prioritize among microorganisms.

The CCL is published every five years. It directs the EPA’s drinking water research for the coming years. Every five years we develop a new list, but we may not necessarily be able to walk away from the prior list. It’s a substantial commitment, when something winds up on the CCL. [The EPA then carries out studies to develop analytical methods for detecting the contaminants, determines whether they occur in drinking water, and evaluates treatment technologies to remove them from the water. —Ed.]

What is risk analysis, and how do you use it to narrow down the data?

Risk analysis is a relatively new field that gathers and analyzes information to evaluate how things behave in the environment, and their potential to impact our health or our environmental quality. For drinking water, we look to see what could cause adverse health effects and the contaminants that have the potential to occur in water; from there, we build a database of the available information. Then we come up with criteria to prioritize among them. We also consult a range of experts in the field, to compare the results and evaluate how well our models worked.

Risk assessment is a tool that helps frame a variety of issues for environmental decision making, not just for drinking water. It can be applied to new technologies, such as nanotechnology, as well as decisions about site usage, such as brownfields, and biological issues.

What are some emerging issues in drinking water safety?

There are recent developments, for instance MTBE (methyl tertiary-butyl ether, a gasoline additive meant to replace lead), which is not highly toxic, but is very mobile. There are naturally occurring substances such as arsenic, which is a carcinogen. There’s quite a bit of arsenopyrite, or “fool’s silver,” in New England’s bedrock. There are also localized issues related to the region’s role in the Industrial Revolution. However, when we compare the potential for chemicals versus microbiological contaminant occurrence, pathogens become significant concerns, particularly in developing countries where water is less adequately controlled.

How safe is our drinking water, overall?

I think people worry about their drinking water too much. The water quality in the United States is high. The systems are very tightly regulated. Not that there aren’t issues in some areas. People worry about tiny levels of things in the environment, when there are big issues in front of them that they could do something about. For example, they might worry about the one-in-a-million risk of getting cancer from low-level pesticides in their water, but continue to smoke cigarettes. Here in New England, our water sources are local, so we have much more control over them than other regions do.

Do you drink tap water?

I do. Millions of dollars are spent to treat it. Why should I buy it and haul it home from the grocery store? I do have a filter on my tap, to filter out lead, which can come from the pipes. Municipal drinking water is more regulated than bottled water. I’m never afraid to drink tap water. Sometimes it doesn’t taste great, because they put chlorine in it, but in Worcester, where there’s ozone treatment, the quality is excellent.

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Last modified: Apr 19, 2006, 22:30 EDT
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