DDT measured directly from Palos Verdes seawater DDT and PCB concentrations measured, for the first time, directly from the waters of the Palos Verdes Shelf, in southern California indicate that shelf sediments are a main source of water contamination, according to research published by Eddy Zeng and co-workers in the current issue of Environmental Science & Technology {ES&T 1999, 33(3), 392-398) The data are relevant to parties trying to decide what to do about sediments contaminated with chlorinated hydrocarbons at the county's largest DDT-contaminated site, off the coast of Los Angeles, Calif. Regulators and responsible parties involved with the site are divided over whether sediment contaminants are being remobilized and dispersed into the environment or are instead locked into the sediments and naturally attenuated (ES&T 1998 32(15) 360A-363A). As part of its Superfund mandate, EPA is about to publish its assessment and recommendation of remediation options in an engineering evaluation and cost analysis. Constructing a sediment cap is one of the options under consideration, according to Fred Schauffler, EPA's project ni3.n3.2cr for the Palos Verdes site, which is both a Superfund site and the subject of a massive ongoing Natural Resource Damages Assessment. At the Southern California Coastal Water Research Project (SCCWRP) in Westminster, Calif., the marine chemists who performed the work believe that shelf sediments are a main source of contaminants found in the water column because the spatial distribution patterns of DDT metabolites and PCB congeners, as well as the DDT/PCB ratio in the water column, are similar to those in the sediments. In addition, vertical profiles of DDT and PCBs decrease nentially with increasing distance from the seafloor This was demonstrated by using state-of-
the-art analytical techniques to overcome the problem of detecting and analyzing low levels of chlorinated hydrocarbons in seawater—more than 1000 liters were sampled for each measurement. SCCWRP is an independent organization that conducts environmental research on behalf of a number of governmental bodies. The new data cast doubts on the significance of Michigan State University (MSU) laboratory experiment findings, published in Science last year, which indicated that bacteria native to the site can quickly convert DDT metabolites into less toxic forms. The SCCWRP results show that the transfer of toxic
metabolites between sediments and ocean water is effective, according to a marine chemist who has studied contamination at the Palos Verdes shelf area. In overcoming analytical measurement problems, this new work demonstrates that DDT and PCBs in sediments are getting into the water and the food web; it strengthens evidence that the contaminated sediments are an environmental problem, he said. Several responsible parties and scientists interested in the site have contended that the MSU laboratory results suggest that natural processes may be cleaning up the site contamination MSU researchers who performed the laboratory studies are conducting further research on the natural attenuation Dhenomenon REBECCA RENNER
MTBE health assessment may loosen California's drinking water standard Two independent committees of scientists reporting to California's Office of Environmental Health Hazard Assessments (OEHHA), which is controlled by the California EPA, separately determined that methyl terf-butyl ether (MTBE) causes neither birth defects nor cancer in humans. OEHHA's Carcinogen Identification Committee and its Developmental and Reproductive Toxicant Identification Committee based their decision on a review of MTBE research. As a result of their findings, California may loosen its drinking water protection standards for MTBE, the gasoline oxygenate added to fuel to create methanol. MTBE, which does not biodegrade quickly, gets into drinking water supplies because of leaking underground gasoline storage tanks and petroleum pipelines, polluted surface runoff from vehicles and contaminated rainwater, and also from motorized watercraft. Maximum contaminant levels in California for MTBE were set temporarily at 35 ppb in 1992 until studies to comply with Propo-
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sition 65, which provides an ongoing mandate to list and annually review chemicals found in the state's drinking water, could be completed. The mandate required OEHHA to decide by January 1999 whether the byproduct of petroleum refining was a carcinogen or a reproductive toxin. "These two findings should put to rest much of the misinformation surrounding MTBE," said Terry Wigglesworth, executive director of the Oxygenated Fuels Association (OFA), in an official
statement. "OEHHA's findings support our belief that MTBE is the most effective weapon we have for fighting air pollution in California." MTBE has pit clean air and clean water advocates against each other. Although it has considerably improved air quality in California since it was added to gasoline in 1996, long-term toxicological studies on MTBE remain to be seen, argued Steve Via, a spokesperson for the American Water Works Association in Washington, D.C., which represents 55,000 members and about 3900 water systems nationwide, detecting MTBE in their water supplies. "We need to wait until we have a better body of evidence to make a decision," he said. "Studies on animals show testicular and lymphoid tumors. There is concern about its effects on water taste and odor. So there is concern from health and public perception [perspectives]." In a draft recommendation to the California Department of Health Services, which has the final approval of contaminant levels, OEHHA has recommended lowering the acceptable primary pollution level to 14 ppb from 35 ppb, said Colleen Murphy, chief counsel for the organization. The secondary maximum contaminant level (MCL) was set in December at 5 ppb, said Rufus Howell, assistant department chief. Primary MCLs are based on the threat to human health, while the secondary category is an aesthetic standard for odor and taste. MTBE, a byproduct of petroleum refining, is not currentiy regulated in drinking water, said Erik Olson, senior attorney specializing in drinking water matters for the Natural Resources Defense Council. MTBE gives water a smell and taste similar to turpentine, said Mike DiMarco, a spokesperson for the Santa Clara Valley Water District, which includes San Jose and much of Silicon Valley. "That is not a desirable component of water, whether or not it causes cancer," DiMarco said. "At around 15 ppb, people can taste
it or smell it. That's our biggest concern." Nonetheless, it is unlikely state secondary standards for MTBE will change. If OEHHA recommends 14 ppb as an acceptable primary level, "the 5 ppb would still be the secondary MCL, and that would be the driver on any cleanups that would occur," Howell said. That's not in the best interest of public policy, said Eric Bolton, speaking for OFA. "Our view is that a 5 ppb secondary standard is lower than is necessary to pro-
tect the public's aesthetic appreciation for MTBE in water. MTBE has been a great contributor to public health by reducing the public's exposure to known human carcinogens like benzene by as much as 40 percent in California in the air. The price for water quality should not have to be choking to death on a remedy for air pollution," he said. California's health services department by law must decide a primary MCL for MTBE by July 1. DEBRA A. SCHWARTZ
EU countries discussing framework for future emissions inventory The Swedish Environmental Protection Agency (EPA) proposed a three-stage process in December for implementing a pollutant emissions register across the European Union (EU). Although most member states already have emissions reporting systems in place, they operate according to national policies, and so, in most cases the data cannot be compared. A 1996 EU directive concerning integrated pollution prevention and control strove to change this state of affairs, laying the groundwork for a European inventory of all significant emissions to air, water, and soil, as well as the sources responsible. The inventory is to be based on data supplied by member states and serve as a tool for evaluating the progress of environmental policy among the EU countries, according to the directive. Because the Swedish government was working on developing its own system at the time the EU regulation was passed, its environmental agency volunteered to analyze existing emissions reporting systems in other member states, as well as the types of pollutants being reported and their responsible sources, said Hakan Bjorndal, an associate professor with the Swedish EPA. As a result of its study, the agency has recommended a three-phase plan that could be introduced quickly, Bjorndal said. Phase one covers a number of
greenhouse gases and sulfur dioxide—substances member states already monitor under the CORINAIR (CORe INventory for AIR emissions) program—and a number of chemicals linked to water emissions. The second phase involves some metals such as lead, mercury, arsenic, and cadmium, as well as chlorofluorocarbons, benzene, ethylene, particulates, and volatile organic compounds. Finally, phase three would add emissions of long-lived organic compounds and certain other metals to the list. While the recommendations received a positive reaction at a December EU meeting, Bjorndal admitted that they were watered down in order to foster agreement among EU countries. Indeed, Anita Ringstrom, deputy director-general for the Association of Swedish Chemical Industries, said that "from our point of view, [the plan] is not very ambitious because it's almost what we have already in our national registers." And a spokesperson for the European Chemical Industry Council noted that most of its big member companies already report a variety of emissions data The organization published an update of its environmental reporting guidelines in November Sweden itself is likely to adopt a more stringent inventory, requiring its industry to report on a greater number of compounds, Bjorndal said. In addition, "We would also like to have a
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