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May 3, 1995 Page 27 PESTICIDE & TOXIC CHEMICAL NEWS "We have to first confirm these health effects, and then see ifthey fit into a pattern," Goldman remarked. "After that, we can develop an appropriate response," she said. In the consent agreement, DowElanco said it would: -- assist EPA by using its best efforts to review files of its parent companies for any information concerning health and environmental effects incidents for pesticide products registered under FIFRA, which the company obtained as a consequence of its 1989 formation; -- waive its right to request a judicial or administrative hearing on the matter, and -- pay the penalty within 30 days, or pay the total civil penalty originally proposed in the complaint, $1,635 million. (*5PTCN 2712,15 pages, $8) 2-VINYL-l3-DIOXOLANE EXPOSURE LINKED TO RABBIT DEATHS IN SECTION 8(e) REPORT Rabbits exposed to 1,3-dioxolane, 2-ethenyl, also known as 2-vinyl-l,3-dioxolane, died after displaying a variety of neurotoxic symptoms, according to TSCA Section 8(e) submission #8EHQ0495-13021, said Degussa Corp. The test substance was used undiluted and applied at 6.61 mg/kg, 66.1 mg/kg and 208.6 mg/kg on male and female rabbits, according to the study. The results were intoxication characterized by hypokinesia, decrease in muscle tone, loss ofrighting reflexes and salivation, which appeared about two hours after treatment and lasted until death. According to the study, deaths occurred between five and 24 hours after treatment, with the LD50 dose for males and females calculated at 25.1 mg/kg. on to In TSCA 8(e) submission #8EHQ-95-13426, Cytec Industries reported the results of a guinea pig maximization study conducted with acrylamide, 50% aqueous, by Stockhausen Laborator' Toxicology in Germany. The results indicated a sensitization rate of 85%, indicative of j sensitization reaction, the submission said. (5PTCN 2716,2 pages, $5) t RISK LINKED TO EARLY-LIFE EXPOSURE A new quantitative cancer assessment on lifetime exposures to vin; the risk of cancer depends on the age at exposure, with higher risks ages, said Environmental Protection Agency's V. James Cogliano. Speaking at the April 25 Conference on Risk Assessment Issues fo Wright-Patterson Air Force Base in Ohio, Cogliano said newborn demonstrate that a brief exposure can induce unseen tumors and hi following long-term exposure later in life. kA n .( k % Page 28 May 3,1995 PESTICIDE & TOXIC CHEMICAL NEWS Cogliano, chief, Carcinogen Assessment Statistics and Epidemiology Branch, EPA's Office of Research and Development, said new quantitative approaches reflecting early-life sensitivity have been developed to supplement conventional approaches to estimating the increased cancer risk from inhaling vinyl chloride. Vinyl Chloride Studies Mav Have Superfund Implications These studies may have implications for Superfund risk assessments as EPA must decipher the risk of inhaling vinyl chloride from nearby dumps, he said, as well as estimating early risks for other . chemicals. Cogliano told attendees of the Ohio meeting that studies on early-life effects of vinyl chloride exposure, especially in a species other than rats, would help resolve how the sensitive period corresponds with humans. But he encouraged more studies in young animals to identify other carcinogens that affect sensitive stages of development. When asked whether other chemicals had been tested, Cogliano replied that vinyl chloride was the first tested and that he would not expect to see a dramatic result with every chemical. "We think it could happen with other chemicals, but we have no data yet," he added. University of Mississippi's Harihara Mehendale also focused on young animals -- specifically, why early postnatal development rats were resistant to a deadly combination ofchlordecoiie (CD) + CCI4 at individually nontoxic doses. Mehendale found that young rats responded faster to tissue injury than adults, and were less susceptible to acute exposure since they were more efficient in stimulating tissue repair. Mehendale focused on liver injury occurring in postnatally developing and adult male rats and found that prompt and exacting stimulation of tissue repair permitted efficient recovery from injury for the younger rats. Mehendale said that perhaps kidneys and lungs should be examined as well. Past research has focused on qualitatively defining causal relationships, but the U.S. Army-sponsored conference focused on the need to better define sources and calculate the magnitude of quantitative estimates of risk to sensitive populations. While the meeting showed a convergence on different methods in variability issues, "early efforts are just that in showing the feasibility of different analyses," said Dale Hattis, a research associate professor at Clark University's Center for Technology, Environment and Development. According to Hattis, there is pressure to better characterize uncertainties to determine whether population subgroups are being adequately protected and whether policymakers are getting the biggest bang for their buck. "There is a need in the current environment to count the bodies," he added. R&S15121H Documents flagged with a "S?" can be ordered through Documents Express by calling 202-544-1980. May 3,1995 Page 29 PESTICIDE & TOXIC CHEMICAL NEWS According to Hattis, it is unlikely that the same factor of 10 rule is appropriate for all different kinds of noncancer risks and different kind ofagents, despite the need for relatively straightforward and standardized treatment of variability in toxic risks. Sociodemographic Factors Affect Susceptibility to Chemicals Ken Sexton of the University of Minnesota's School of Public Health noted how sociodemographic variables, such as class and race, can affect exposure-related and susceptibilityrelated attributes which, in turn, can lead to the well-documented disparities in health status among populations. "There has been a surprising lack of research" in occupational and environmental studies on this issue, said Sexton, who helped launch EPA's National Human Exposure Assessment Survey, an interagency initiative to conduct exposure surveillance ofAmericans. Sexton defined individuals and groups at potentially greater risk when they are exposed above a health-related benchmark, more susceptible to the effects of exposure, or both. Too much regulation also can render groups more susceptible to risk, Sexton said. Increasing regulation can affect socioeconomic status, in turn adversely affecting health, he said. The congressional debate on risk assessment is raising important questions, such as the impact of cumulative risk, comparative risk and total risk, and bringing together epidemiology and toxicologv into "one sphere," he said. Multiple Chemical Sensitivity Syndrome Explored. How multiple chemical sensitivity is defined will determine how many people are affected, said Claudia Miller, who for the past two years has been involved with Houston Veterans Affairs' Regional Referral Center for Gulf War veterans. Miller outlined an emerging theory on chemical sensitivity. The idea that it "may be a mechanism for disease posits that a broad spectrum of chronic illnesses, ranging from asthma and migraine to depression and chronic fatigue, may be the consequences of environmental chemical exposures," she said. First, an initial exposure event interacts with a susceptible individual, causing loss of tolerance to everyday, low-level chemicals, Miller said, adding that substances then trigger symptoms that perpetuate the illness. Seventy-one percent of Gulf War veterans surveyed said they have chemical intolerances, Miller said. David Oberstreet, research associate professor. University ofNorth Carolina at Chapel Hill, presented findings on his research on Flinders Sensitive Line rats, which are selectively bred to be more sensitive to organophosphate diisopropylfluorophosphate. These rats showed similar symptoms to MCS humans, including depression and reduced activity and appetite, he said. R&S151219 1