Announcing...
Free Enrollment in ACS Short Courses for Unemployed Members The ACS is pleased to provide this expanded career services program for unemployed members to help them upgrade their knowledge and improve their networking opportunities.
To obtain a calendar of upcoming courses, write or call the Department of Continuing Education, American Chemical Society, 1155 Sixteenth Street, N.W., Washington, DC 20036. Phone: (800)227-5558 or 202-872-4508.
CORRESPONDENCE
Internet resources
Dioxin inventory
Dear Editor: Thank you for the great article on the Internet and the way the World Wide Web can be used by environmental professionals (February 1996). I even agree with the author's analysis that perhaps the DIALOG information service is better than the Internet for researching some items. Very nice work. It makes me glad to have been a member of the American Chemical Society for 25 years and an ES&T subscriber for nearly eight years.
Dear Editor: In a review of the U.S. dioxin inventory (Feb. 1996, p. 82A), Thomas and Spiro make the statement that "there are no dioxin emission data on forest fires per se." This is incorrect. Clement and Tashiro reported in 1991 (11th IInernational Symposium on Chlorinated Dioxins and Related Compound,, School of Public Health, University of North Carolina, Chapel Hill, NC, 1991) that forest fires do produce dioxins, perhaps to the extent of 58,700 g/yr based on their data (up to 15 pg/m 3 of PCDDs and up to 9 pg/m 3 of PCDFs)
LARRY SCANLAN State of Utah Division of Drinking Water Salt Lake City, Utah 84114-4830 Dear Editor: In Tony Reichhardt's feature on Internet resources, Michael Buchman commented on the lack of ecotoxicity data and ecological risk information on the Net. The Environmental Sciences Division of Oak Ridge National Laboratory has recently opened a home page devoted to resources for ecological risk assessment. The URL for the home page is http://www. hsrd.ornl.gov//ecorisk/ecorisk.html. The site currently includes a database of ecotoxicological benchmarks that can be downloaded and searched. The benchmarks, which are updated regularly, are concentrations of chemicals in ambient media that are estimated to be thresholds for ecological effects. Benchmarks are provided for aquatic biota in water benthic communities in sediments, plants in soil, earthworms and microbial processes in soil, and oral exposures of wildlife. The page also includes reports explaining the derivation of the benchmarks and sources of the data. Questions or comments can be addressed to
[email protected]. GLENN W. SUTER II BRADLEY E. SAMPLE Environmental Sciences Division Oak Ridge National Laboratory Oak Ridge, TN 37831-6038
1 8 4 A • VOL. 30, NO. 5, 1996 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS
Using remote collectors/detectors in August 1989, Clement and Tashiro collected and analyzed air samples from two of the 200 annual prescribed forest fires burns in Ontario. The patterns of observed dioxin isomers resemble those in incinerator fly ash, and although the concentrations in air are low, the authors conclude that "large forest fires could produce significant total dioxins/ furans." There was excellent agreement in the results from co-located samplers in these fires. GORDON W. GRIBBLE Department of Chemistry Dartmouhh College Hanover, NH 03755-3564 Authors' response Gribble is correct in pointing out that Clement, Tashiro, and colleagues have measured dioxin in air samples over forest fires (C. Tashiro, Chemosphere, 1990, 20, 1533.) These measurements are indeed important indicators that forest fires do produce dioxins. However, the data do not allow estimation of the amount of dioxin produced, because there is no way to relate the volume of air sampled to the amount of forest combusted. The 58 700 g/yr estimate mentioned in Clement and Tashiro's 1991 presentation was not based on their data but was from Sheffield's 1985 dioxin inventory for Canada
