To screen or not to screen?

Testing breaks new ground but raises new questions.

Requirements for monitoring the effects of endocrine disrupting compounds (EDCs) and other substances are starting to show up in discharge permits. Although many waste-water departments haven't implemented such regulations, some, such as California's Orange County Sanitation District, are taking pre-emptive measures.

“We don't have monitoring requirements in our NPDES [National Pollutant Discharge Elimination System] ocean discharge permit, but we've been doing it since 2000,” says Jeffrey Armstrong, a senior scientist with the district's Environmental Laboratory and Ocean Monitoring Division. “The most responsible course we can take is to have the answer to that question before it's asked.”

The district works with research groups at the University of California Riverside and California State University Long Beach to perform vitellogenin assays. The district supplies fish, sediment, receiving water, effluent samples, and ecological expertise, and the labs conduct the effects-based tests. In addition to examining reproductive effects and feminization of fish, the studies look at growth, stress response, predatory responses, immune system dysfunctions, and overall health.

“First we look at the effects, then narrow it down as to which compounds are eliciting the effects,” said Armstrong. “We haven't detected complete feminization in our samples, but we see a higher level of vitellogenin, which is evidence of exposure to estrogenic compounds.”

Then the question becomes, does evidence of exposure imply evidence of effect? “If there's no effect is there really a concern?” says Armstrong. “We're trying to get a handle on that before we spend a lot of resources correcting a problem that might not exist.”

Other considerations muddy the waters further.

Some effects may not surface for two or three generations after exposure, so they won't be seen in the test organism. The pesticide DDT, for example, is an endocrine disruptor and, though banned in 1972, still persists in sediments. Regulators also have to factor in the possible effects of naturally occurring estrogens. If old contaminants or naturally occurring compounds are responsible for the effects, regulating current discharge won't correct the problem.

And studying effects on fish is just one piece of the puzzle.

“What about the effects on invertebrates?” says Armstrong. “And in the case of a freshwater drinking source, the human health component enters into it. In that case, chemical analysis may be more important than effects-based tests.”

EPA is still investigating test methods and has yet to establish a prescribed method. The Safe Drinking Water Act defines maximum contaminant levels by their toxic effects, but traditional toxicity testing doesn't work for EDCs.

“It's designed to assess acute effects of short-term exposure—does it kill you or not?” says Armstrong. Testing for EDCs, on the other hand, requires studying life cycles and long-term functions. “We're looking at sublethal, sometimes cellular and sub-celluar, effects,” he says. “It completely changes the paradigm for how we look at toxicology.”

The quest for appropriate tests is a global effort. The American Water Works Association Research Foundation (AwwaRF) is working with the Global Water Research Coalition on screening methods.

“We're testing five of the biological assays and comparing them to chemical analyses,” says Robert Renner, executive director of AwwaRF. “This is a first step. There are no epidemiological studies to show endocrine activity in human beings. The EPA may do mammalian assays next.”

Testing is just the first hurdle for treatment plant operators. Eventually, regulations for removing EDCs and other micro constituents can be expected. AwwaRF has published the results of its research on the effectiveness of various treatment processes in “Removal of EDCs and Pharmaceuticals in Drinking and Reuse Treatment Processes.” The report covers conventional and advanced water treatment processes and presents bench-, pilot-, and full-scale results. Also included are recommendations for utilities.

— Diana Granitto is a free-lance writer based in Hoffman Estates, Ill.

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