ENVIRONMENTALNEWS Risk assessment draft gives WTI incinerator clean slate
O
ne of the most detailed sitespecific risk assessments ever conducted gave a clean bill of health to the most controversial hazardous waste incinerator in the United States, according to an EPA draft released in November. Still to come, however, is a peer review of the 3300-page, seven-volume assessment for Waste Technologies Industries' (WTI) incinerator in East Liverpool, OH. That review, by a 21member panel, is set for Jan. 11 and 12 in Washington, D.C. The assessment concludes that human health risk falls within a range generally considered acceptable, according to Harriet Croke, head of the Minnesota, Ohio, and Wisconsin permit section for Region V It includes a detailed human health risk assessment, a screening study of ecological risk, and an accident analysis. It finds noncancer risk to be acceptable and cancer risk to be less than one in one million for a resident living near the incinerator and eating locally raised meat and dairy products. The assessment is one of the first to examine the indirect risk from consuming local food and drinking water contaminated with dioxin and other stack emissions. The risk of an accident having a major off-site consequence was "unlikely," according to the draft, and the ecological screening found little impact. Several years in preparation, the assessment cost more than $1 million and drew staff from throughout the Agency as well as four contractors that prepared most of the analysis. One of the contractors, ENVIRON Corp., analyzed human health risk and the probability of an accident. Particularly because of ENVIRON, conclusions in the WTI draft are being criticized by local residents
who point to ENVIRON's role in another risk assessment: EPA's assessment of the overall risk of dioxin. In that review, ENVIRON is under contract to the American Forest and Paper Association and has challenged EPA's conclusions that dioxin is a probable human carcinogen that causes noncancer health effects at low exposure (ES&T, Jan. 1995, p. 31 A). The reason WTI's risk assessment is so detailed is due to longrunning community opposition to the incinerator's emissions as well as its location—300 feet from residences and a drinking water source, the Ohio River, and 1100 feet from an elementary school. The school is on a bluff that puts it at eye level with the top of the incinerator's stack. However, WTI is considered a world-class facility because of its design and pollution controls, and the Swiss-owned incinerator has been given a green light by
More than 10 years of community opposition due to location and emissions led EPA to conduct a comprehensive risk assessment for WTI's hazardous waste incinerator in East Liverpool, OH.
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state and federal regulators to operate under limited commercial operation while the risk assessment is completed. This spring, EPA and Ohio regulators will use the assessment to determine whether WTI may move forward to full operation. Although many metals and chemicals emitted by the incinerator were considered, dioxin was found to be the "main driver" when considering human health risk because of its cancer potency said Dorothy Canter, who led EPA's risk assessment team. She called the assessment "groundbreaking" because of the detail and the number of scientific disciplines taking part in the review. The study involved experts on human health, toxicology, air modeling, combustion, ecology, industrial accidents, and other fields. On the other hand, she also said the review was very expensive and doubted such a comprehensive risk assessment would be called for again. "This is a personal opinion, but why consider all pollutants if you know [dioxin] is going to be the trigger?" She noted that WTI was "data rich" because of information that had been collected on emissions and deposition as well as housing patterns, weather, and terrain. For instance, she noted that because of long-running opposition and several court cases, an incredible level of information is available on WTI. This would not be the case, she said, with other incinerators, boilers, furnaces, and cement kilns that burn hazardous waste and are expected to conduct risk assessments under the Agency's "combustion strategy," released in May 1993. Despite the detail, local residents remain worried, according to Alonzo Spencer, president of Save Our County, Inc. His concerns center on the synergistic effect of the mix of hundreds of chemicals coming out of the
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stack right next to homes ana tne school, the possibility of scientists "fudging" risk assessment data, and ENVIRON. "ENVIRON is questionable because of its ties to industry. I would have thought [EPA] would get someone that is more evenhanded, rather than choosing someone right out of the gate that appears to be in a conflict of interest. It makes this all the more questionable. When dealing with something this critical, there shouldn't be a 'question.' We're talking about people's lives." In response, Croke said ENVIRON's role was a concern to EPA, too. But the Agency conducted an in-depth study, she said, and concluded that there was not a conflict, provided ENVIRON did not
Despite the study's scope, residents remain concerned about emissions, the credibility of risk assessment data, and the role of a key study contractor. supply toxicological data. "ENVIRON's role was to use EPA data and to perform calculations under our very close oversight." Currently, risk assessments are not mandatory for facilities that burn hazardous wastes, but most commercial incinerators have conducted them. A recent EPA policy encourages owners of industrial furnaces, cement kilns, and boilers that burn hazardous waste to do assessments, however. But these are less extensive than WTI's assessment, said Alex McBride, an EPA environmental protection specialist. In the future, EPA may rely less on risk assessments for burners, McBride added, and more on emissions standards, once new standards are set in December 1996. —JEFF JOHNSON
NEWS SCIENCE Researchers find unexpectedly high levels of contaminants in remote sea birds A three-year, EPA-sponsored study by the World Wildlife Fund (WWF) has found concentrations of persistent organic pollutants in sea birds living on Midway Island in the north Pacific that are almost as great as levels found in birds in the Great Lakes. These chemicals have previously been detected in high concentrations in organisms in the Northern Hemisphere, but this research is the first to indicate that high levels of contamination also occur in remote tropical regions. Adult black-footed albatrosses living on Midway were found to have concentrations of polychlorinated biphenyls (PCBs), dioxins, furans, and other dioxin-like chemicals in their eggs of 124 picograms per gram expressed as toxic equivalents. This level is within the range of concentrations where sensitive avian species show adverse reproductive effects. This toxic-equivalent measurement is the sum of the toxicity of all of the dioxin-like chemicals thought to affect an organism in the same way, converted to the effect of 2,3,7,8-TCDD, the most toxic member of this chemical family. "What our research indicates is that we are right at the threshold. There is no more assimilative capacity," said Michigan State University toxicologist John Giesy, who discussed the results at the November meeting of the Society of Toxicology and Environmental Chemistry in Vancouver, Canada. "Any TCDD-like pollutants that are added now will push us above the threshold and give an effect. This is especially true because the dose-response relationship for TCDD is so steep."
Reproductive effects from persistent organic pollutants were documented in new study of albatrosses on Midway Island in the north Pacific. (Photo courtesy of J. P. Giesy, Michigan State University.)
This new study adds to accumulating evidence based on ocean water samples and studies of marine mammals that persistent organic pollutants are dispersed by global atmospheric transport and cycling processes to create exposures in areas far from the sources. Using methods developed to study fish-eating birds in the Great Lakes (ES&T, March 1994, p. 128A), Giesy and colleagues Rosalind Rolland and James Ludwig studied two similar species that nest on Midway: Laysan and black-footed albatrosses. They measured concentrations of polychlorinated, diaromatic hydrocarbons including PCBs, dioxins, dibenzofurans, and pesticides in the birds' eggs, blood, and tissues. They also studied the albatross population and used historical population data. In the Great Lakes and other areas, high exposures have been correlated with
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