EPA’s draft is overly simplistic because it doesn’t account for food webs, counters U.S. Geological Survey (USGS) scientist Theresa Presser, in Menlo Park, Calif. As an example, Presser cites the San Francisco Bay, where bass that feed on algae have low selenium levels, but sturgeon that feed on bivalves, which concentrate selenium, get a high dose. To know which wildlife are at risk, it’s necessary to understand the ecosystem, she says. In addition, EPA’s draft guidelines say little about implementation—the details of what, when, and how to analyze fish, or how to set water discharge permits so that fish tissue concentrations stay low. Implementation oversights in EPA’s mercury tissue guidance, which is intended to protect humans who eat fish, have caused chaos in states and agencies, according to USGS scientist Steve Schwarzbach in Sacramento, Calif. But EPA would
have produced implementation guidance for selenium if the new standard hadn’t been sidelined, counters EPA selenium project manager Charles Delos, in Washington, D.C. The draft’s analysis of fish data yields a good standard that addresses dietary exposure, according to Delos, who defends the draft. The proposal to develop a wildlife standard for California uses a method with ample uncertainty factors, he says. “USFW knows what criteria they want in the end. With this methodology, they’ll get it,” he said. California’s site-specific selenium guidelines to protect wildlife could become a model for national standards, say many aquatic toxicologists. In the meantime, discharging industries are pushing EPA to get its tissue concentration draft out of limbo. —REBECCA RENNER
Invasive species drives selenium poisoning
USGS
Invasive zebra mussels, which are bioconcentrating toxic selenium in the Great Lakes, may be poisoning ducks that eat the bivalves, according to new research from the Long Point Water and Wetlands Research Fund, a Canadian nonprofit organization located on Lake Erie. If further studies confirm that the high selenium burdens in waterfowl are causing reproductive or health problems, the findings could put pressure on governments to regulate selenium sources around the Great Lakes, researchers say. Selenium burdens in lesser and greater scaup, two species of diving ducks, averaged 18 and 28 parts per million (ppm), dry weight, and ex-
Because zebra mussels are bioconcentrating selenium, they may be poisoning wild ducks.
ceeded safe thresholds, according to preliminary analyses by Scott Petrie and colleagues. These levels are alarming because tissue concentrations of 4–9 ppm selenium, dry weight, begin to disrupt physiological functioning in mallards, and at 9 ppm the trace element impairs reproduction, leading to fewer eggs and deformed hatchlings, Petrie says. However, these types of effects have not yet been studied in scaup, and more research is needed to determine whether the diving birds can tolerate the high selenium levels, he says. Zebra mussels taken from the guts of birds contained 8.1 ppm selenium, dry weight, well over the toxic threshold of 3 ppm selenium that other researchers consider safe for aquatic foodchain organisms eaten by fish and birds, he adds (see “California to develop selenium standard for wildlife,” p 274A). Tissue from ducks sampled in the mid-1980s, just prior to the accidental 1986 introduction of zebra mussels to Lake St. Claire, contained 6–9 ppm selenium, roughly
News Briefs ES&T Associate Editors cited Three ES&T Associate Editors, Walter Giger, Ron Hites, and Jim Pankow, have been named to the list of highly cited journal authors in all fields of science maintained by Thomson ISI, also known as the Institute for Scientific Information. The ISI’s “highly cited” index is widely recognized as the definitive source of journal citation information. According to an ISI spokesperson, Hites, Giger, and Pankow are among the 248 most highly cited researchers in ISI’s ecology/ environment category, based on articles published between 1981 and 1999. Their influential publications rank them with the top 0.5% of all publishing researchers worldwide, according to Thomson ISI. For more information, go to http://isihighlycited. com/formBrowse.cgi.
Maximizing EPA and industry partnerships To promote collaboration in the development of environmental technologies between industry and the U.S. EPA, the National Technology Transfer Center (NTTC) launched a new website in May. The site highlights projects and facilities currently funded through EPA’s $500 million technology R&D budget. EPA cannot commercialize any technologies it develops, but technology transfers and partnerships with industry help the agency justify federal spending. Based at Wheeling Jesuit University in Wheeling, W.V., NTTC is a technology management group that identifies opportunities and facilitates communication to build partnerships, such as EPA’s Environmental Technologies Partnership. The site lists EPA research opportunities for industrial scientists and provides an organized primer on technology transfers between the federal government and the private sector. For more information, go to www.nttc. edu/etprogram.
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Environmental▼News one-quarter to one-half of presentday levels, Petrie finds. Over the past 15 years, the scaup have switched from eating native snails and crustaceans to consuming the abundant zebra mussels. At the same time, scaup populations in North America have declined from a high of 8 million birds in 1972 to 3.7 million in 2001, with most of the decline occurring since the mid1980s after zebra mussels invaded the Great Lakes, he says. It is tempting to conclude that selenium contamination from eating zebra mussels on the lower Great Lakes is contributing to the downward spiral in scaup numbers, Petrie says. Even if selenium inputs to the Great Lakes have not
changed much in 15 years, zebra mussels, by filtering vast quantities of suspended matter, have bioconcentrated selenium and increased its availability to the ducks, he says. Zebra mussels can accumulate 20–370 ppm of selenium and still maintain stable populations, Petrie says. Few other species accumulate selenium to such levels, probably because the mussels filter so much more water. Although the Great Lakes basin has many potential sources of selenium, such as coal-fired power plants and landfills, researchers have not yet documented a widespread selenium problem in the lakes, says Peter Hodson, director of the School of Environmental
Studies at Queens University in Kingston, Ontario. Little is known about selenium because the contaminant is not regularly monitored by either the United States or Canada in the Great Lakes, says Alice Dove, watershed scientist with Environment Canada. Nevertheless, studies on North Carolina reservoirs have shown that nontoxic levels of selenium in water and sediments bioaccumulate in the aquatic food chain to levels high enough to kill fish, adds Hodson. If the link between zebra mussels and selenium poisoning is borne out, governments would have to track down the selenium sources and curb releases, he says. —JANET PELLEY
A 2001 expert literature review that concluded hexavalent chromium, Cr(VI), in drinking water is unlikely to cause cancer has been thrown out by the California EPA amid allegations that the scientific panel responsible for the report was manipulated to favor corporate interests. Nevertheless, the University of California’s Office of the President, which organized the blue-ribbon panel, and the panel’s chair, University of California–Davis toxicologist Jerold Last, stand behind the report, which was launched as a review of California’s 1999 public health goal of 2.5 parts per billion (ppb) total chromium. By comparison, the U.S. EPA set a standard of 100 ppb for total chromium in 1991. California’s strict 1999 goal “was based on a flawed study that was never intended to be used for risk assessment and that no other public health agency in the world has used, and that’s what our panel told the state,” Last says. The panel’s controversial findings are also consistent with recent evaluations by the U.S. EPA, the Agency for Toxic Substances Disease Registry, and the International Agency for Research on Cancer.
CORBIS
Allegations of manipulation lead to withdrawal of Cr(VI) report
Erin Brockovich (shown here as played by Julia Roberts) alerted the world to the perils of chromium contamination.
Cr(VI) is a human carcinogen that is widely agreed to cause lung and nasal cancer in anyone who inhales it at high concentrations. But whether Cr(VI) in drinking water causes cancer is controversial. Most experts say that the stomach’s acidic, reducing environment converts ingested Cr(VI) to nontoxic Cr(III). However, some scientists caution that the stomach’s reduction of Cr(VI) could be incomplete. “We don’t know that all Cr(VI) gets changed to Cr(III),” says Max Costa chair of the Department of
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Environmental Medicine at New York University. “Some people change Cr(VI) better than others.” California EPA head Winston Hickox abandoned the panel’s report after hearing allegations from attorney Gary Praglin to the California State Senate in February and March. Praglin, one of the attorneys suing utility Pacific Gas and Electric (PG&E) over this issue, claimed that lobbyists paid by the company tried to stack the panel; that part of the report was copied from industry-sponsored publications; and that consultants had sought to discredit an epidemiological study by ghostwriting a followup that was published as work by the original authors. Dennis Paustenbach, a consultant toxicologist with Exponent in Menlo Park, Calif., and a target of intense criticism by Praglin because of prior work for PG&E, says that the lawyers are trying to discredit the scientific findings by attacking the process. “Praglin has taken dozens of snippets of testimony collected over several months out of context and has strung them together into a story which feels compelling to those who have not had a chance to read all of the testimony,” he claims. “This isn’t a case of industry manipulating science. It’s a case of lawyers manipulating the regulatory process.”
