Proposed sediment contamination guidelines to look at chemical mixtures A proposal for national guidelines to assess sediment contamination from chemical mixtures in fresh and estuarine water and the marine environment will be reviewed this month by EPA's Science Advisory Board. The decision to propose sediment quality criteria (SQC) for mixtures of polycyclic aromatic hydrocarbons (PAHs) will affect a wide range of regulatory decisions, including Superfund cleanups and permits for industrial discharges and dredging, according to EPA Office of Water officials Since 1990 EPA has been working on a strategy to regulate and remediate contaminated sediments that pose ecological and human health risks in many US inland, estuarine, and coastal waters, according to the agency. More than 10 federal statutes give EPA authority to address contaminated sediments, but there are no national guidelines to indicate what levels of contamination cause adverse effects. A handful of states, including Washington, and federal programs such as EPA Region 10, EPA's Office of Research and Development (ORD), and the National Oceanic and Atmospheric Administration have adopted their own guidelines using a variety of theoretical and empirical approaches. Once EPA and its offices finalize SQCs, states must either use the EPA values or fldopt policies tlicit 3xe at legist sis protective as the national standard. In 1993 EPA proposed criteria to protect bottom-dwelling organisms from two pesticides, dieldrin and endrin, and three PAHs: acenaphthene, fluoranthene, and phenanthrene. Criteria for these individual PAHs will be scrapped in favor of criteria for mixtures because these compounds rarely occur alone in the environment and because recent experimental and theoretical results justify a mixtures approach, according to Dave Mount, a toxicologist at EPA's National Health and Environmental Effects Research Laboratorv-Midcontinent Ecology Division Duluth Minn PAHs, along with heavy met-
als, polychlorinated biphenyls, and pesticides, are the most widely reported contaminants in sediments, according to EPA. Sources of PAHs in the environment are linked to human activities such as oil spills and fossil fuel burning, although some may result from natural sources
Critics are concerned that the sediment quality criteria will be used as "pass/fail" numbers by regulators. The new proposal is based on the same theory—equilibrium partitioning—as the previously proposed SQCs, but it incorporates recent research results on PAH toxicity, according to Heidi Bell, a toxicologist in the Office of Water. Equilibrium partitioning assumes that the bulk sediment concentrations of chemicals, organic carbon, and pore water are in equilibrium and then calculates criteria so that the pore water meets regulations for water quality Recent research has shown that the toxicity of many PAHs is enhanced by sunlight
The proposals are founded on a model for summing PAH toxicity developed by ORD toxicologist Richard Swartz. "Our belief is that the effects of PAHs are additive once account is taken for the individual toxicity. Experimental evidence, when it is available, backs that up," Mount said. EPA officials are confident they can justify the proposal, because numerous methods for determining sediment guidelines to protect bottom-dwelling organisms all yield a similar result. Approaches for developing guidelines to protect aquatic resources or human health can be divided into those based on an empirical analysis of concentration and biological effects data and those based on modeling The ITIHUV different approaches provide similar guideline values according to Swartz "This convergence means that the mixture PAH guidelines must be about right since different methods do come to the same conclusion " said Mount Proposals for SQCs have farreaching consequences. EPA is currentiy developing a manual for states and federal agencies on how to use SQCs because they affect regulatory decisions covering a wide range of activities. Among these are permits for point source discharges and ocean dredging. Once finalized, industrial discharge permits under the National Pollution Dis-
Seeking contaminated sediment "hot spots," EPA's research vessel Mudpuppy ccllectt samples up to 15 ft deep in the Great Lakes. (Photo courtesy of Ohio EPA/U.S. EPA)
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charge Elimination System will be protective for sediments. EPA has not yet decided how the criteria will be used in dredged material permitting, a function shared with the U.S. Army Corps of Engineers. But Corps officials are opposed to the development of SQCs, according to Joe Wilson, chief of the Corps' ocean-dredging permitting branch. Current methods provide latitude for regulators to consider economic effects in their decisions about ocean dredging and dumping he said. But he fears that SQCs will be used as strict pass-fail numbers: If contamination exceeds the SQC there will be no ODtion for further action Whether SQCs should be used as pass-fail numbers or as a screening tool to identify poten-
tial contamination problems is a concern of regulators and the regulated community. Some scientists caution that SQCs should not be used as pass-fail numbers. "We need to avoid the search for the magic index," Swartz said at a presentation on PAH contamination guidelines at the Society of Environmental Toxicology and Chemistry 1996 annual meeting, Nov. 17-21. "These problems are inherently complex, and the answer must reflect this complexitv " These same scientists argue that better suited for use as screening tools for evaluating contaminated sediments because each situation is different and requires case-specific treatment To be part of the dischargepermitting process, SQCs must
N.Y. state begins 5-year Love Canal health study that includes noncancer effects Current and former residents of Love Canal, N.Y., will be the subjects of a new five-year study launched by the New York State Department of Health to determine whether they are suffering higher than average disease rates. The study is the most comprehensive investigation of Love Canal residents' health and the first to emphasize noncancer health effects, state officials said. Love Canal came to national attention in the late 1970s, as state and federal officials discovered that Hooker Chemical Corp., among other parties, had dumped more man 20,000 tons of chemicals, including dioxins, polychlorinated biphenyls, toluene, benzene, lindane, and chlorobenzene into the "canal," a trench about 60 feet wide and nearly a mile long. At the time, state officials found that women living close to the canal were at greater than average risk of having miscarriages and giving birth to babies with low birth weight and growth retardation. A researcher hired by residents also found increased rates of nervous breakdowns and urinary tract disorders, but no full investigation has been conducted to date. The state has wanted to con-
duct a comprehensive study for years but did not have the funds, said Alice Stark, director of the Department of Health's Bureau of Environmental and Occupational Epidemiology. Under an agreement with federal officials, $3 million was earmarked for this research in a 1995 settlement between Hooker's parent company, Occidental Chemical Corp., and the U.S. Department of Justice. The results of the Love Canal study should help researchers understand whether chronic exposure to low levels of hazardous chemicals causes cancer and reproductive and other problems, said Stark. Because decades have passed since the community was exposed, the study may confirm whether high rates of diseases such as cancer and heart disease are associated with residents' exposure, she said. The research also should shed light on the question of second-generation reproductive effects Stark said The study, which got under way in September, will be guided by an eight-member technical advisory panel, of whom five will be selected by the Department of Health and three by the community. Researchers will spend the first year locating nearly 7000 people who lived near the canal
function as pass-fail numbers, say regulators who are familiar with the program. This is because, for discharge permitting, SQCs will be used in predictive models. This approach may cause problems, however, because once SQCs have the status of pass-fail numbers in one program, the precedent is set for them to have this status in other programs. "The problem appears to be that if we use them one w3.v in one program we'll have to use them the same way in all programs " regulator said. After the Office of Water submits its proposal to the Science Advisory Board this month, the draft document will be released for peer review and public comment, said Bell. — REBECCA RENNER
between 1940 and 1978. Investigators also will review state and national cancer, birth defects, and other disease registries and conduct a survey of other health effects that Stark said typically are not found in registries. Health effects information will be compared with exposure data. In the late 1970s, researchers conducted extensive soil, air, and water sampling. Although these studies were not conducted systematically, Stark said they provide an extraordinary amount of environmental data. The department will not be able to reconstruct past doses, but, said Stark, "If we can tell [residents] they are statistically at higher risk, they can make their physician aware of that and, hopefully, diagnose illnesses early." The information also should be helpful for other communities with hazardous waste sites, she said. Some former residents, however, have doubts about the state's ability to conduct a scientifically credible investigation. Former resident Lois Gibbs, founder of the Citizens Clearinghouse for Hazardous Waste, believes the investigation will be faulty because it will use data from poorly conducted studies. The state wants to put Love Canal behind it and prove that current residents do not face increased risk, Gibbs said. PAT PHIBBS
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