Are regulators relying on inaccurate industrial air emission inventories? The long-held suspicion that estimated industrial air emission inventories for factories differ significantly from what is actually being released has been validated in a paper published in the Proceedings of the National Academy of Sciences (Vol. 94, June 1997, p. 6596). Regulators rely on estimated industrial emission rates, "which are often outdated, incomplete, or inaccurate," the researchers wrote. Emission inventories are the backbone of air pollution control strategies. Because it is costly and time consuming to gather air quality data from an outdoor monitor to determine what is being discharged, regulators require polluters to supply estimates of expected emissions. Businesses calculate their emissions on the basis of an EPA list of estimated emissions for sources ranging from small dry cleaners to petrochemical plants. Regulators use the inventories to determine an area's compliance with air quality standards and to develop controls for areas that do not meet the standards. The accuracy of these
inventories will assist states as they move to meet the new standards for ozone and particulate matter, EPA officials said. Regulators admit, however, that the accuracy of estimates varies. To help the Texas Natural Resources Conservation Commission pinpoint the sources of volatile organic compounds (VOCs) in
Estimated industrial air emission rates "are often outdated, incomplete, or inaccurate." —Ronald Henry, University of Southern California the heavily polluted Houston area, Ronald Henry, University of Southern California (USC), along with Clifford Spiegelman and EunSug Park, Texas A&M University, and John Collins, USC, compared ambient air quality data collected over a six-month period with an inventory of emissions
that had been reported by facility managers. The ambient data were collected by an automated gas chromatography monitor at a site run by the commission and located downwind from a large petrochemical complex near the Houston Ship Channel. The reported emission inventories were provided by the commission for all industrial sources of nitrogen oxides and organic gases in the Houston area. The reported inventories included the description, location, and emissions rates (in tons per year) of all individual sources in a company facility. The researchers collected ambient data hourly at part-perbillion levels on total nonmethane organic carbon and 54 VOCs. This information was then combined with data on wind direction and speed. Applying the multivariate receptor model, the team worked backward to identify a chemical profile that led to the pollution source. The inventory of industrial VOC emissions, as reported by several petrochemical facilities in the area, did not—except for one small source—reflect what is being emitted. The largest sources in the inventory did not even show up in the team's observed
USDA food survey finds many pesticides, few violations Although pesticide residues have been detected on 65% of fruits and vegetables sold in the United States, "dissipation of residues between farm and marketplace and standard food preparation techniques" cumulatively minimizes the risk to consumers, said the latest annual survey by the U.S. Department of Agriculture (USDA). The study analyzed fresh and processed samples collected in 1995. Despite the relatively high percentage of pesticide residues on fruits and vegetables, USDA said that just 3.8% appeared to violate EPA tolerance limits. About half the apparent violations were found on spinach. Of the total, 87.8% of the food samples were domestic. Even so, the number of probable tolerance violations cited in the 1995 survey was up from 1.3% in 1994 and 1.5% in 1993. USDA said it could not draw any conclusions, because year-to-year
variations in sampling techniques made comparisons impossible. The annual report is designed to help EPA's risk assessment process during the re-registration of pesticides. Jay Feldman of the National Coalition Against the Misuse of Pesticides said the findings were of concern because Congress adopted tougher pesticide standards when it passed the Food Quality Protection Act of 1996. The USDA study used earlier tolerance limits that critics have said do not account for the high fruit and vegetable intake and the higher susceptibility of children to pesticide exposures. The USDA also is researching consumption data to help EPA develop more protective tolerance levels. "The cumulative risk, the risk to children, is certainly much greater, simply because they were using outdated tolerances," Feldman said.
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All told, 7524 fruit, vegetable, and wheat samples were collected from 39 states and 17 foreign countries. A total of 69 pesticides—insecticides, fungicides, herbicides, and growth regulators—were detected on fresh, frozen, and processed fruits and vegetables. Postharvest applications—mainly preservatives, growth regulators, and fungicides—were responsible for 29% of the total detected. A total of 10 pesticides were detected on 79% of sampled wheat. The most common were two insecticides, malathion and chlorpyrifos methyl. Testers also found residues of the DDT metabolite DDE on 10% of the fruit and vegetable samples even though the compound has been banned in the United States since 1972. Copies of the annual report are available from USDA at (202) 720-5231. —RAE TYSON
