LETTERS Selenium, correction Dear Sir: An error has ,een noted in the ES& T article “Toxic by-products of coal conversion” (November 1980, p. 1283) and the paper “Characterization of coal gasification ash leachates using the RCRA extraction procedure” presented at the Symposium on Environmental Aspects of Fuel Conversion Technology, V. The selenium concentration in the RCRA extractant of the Texaco gasifier slag is < 1 p g / i rather than the reported 900 pg/L. This error was apparent after reexamining the original analytical data compiled by this laboratory. The actual value is less than the detection limit of the analytical method (1 pg/L). To confirm the data, the same slag was extracted in duplicate by the RCRA procedure. The resulting leachate was analyzed in duplicate by two different EPA-approved atomic absorption methods, i.e., hy-
dride generation and graphite atomizer with Ni(N03)2 matrix modification. All results again were below the detection limit of 1 pgJL. These result’s indicate that the Texaco slag does not “come close to violating the standards” as was stated in the article. Guy M. Crawford
Radian Corporation
Austin, Tex. 78766
Editor’s comment The 9OO-pg/L figure for selenium found in “Texaco, slag” was included in the original table included in a paper presented by Kar Yu of TRW, lnc. at the EPA Symposium on Environmental Aspects of Fuel Conversion Technology, V (St. Louis, Mo.). Analysis on air quality policies Dear Sir: Your brief report in “Currents” (ES&T, November 1980 p. 1275-76) concerning the hearing by
the House Commerce Committee’s Subcommittee on Oversight and Investigation into the award by DOE of a contract to Environmental Research & Technology, Inc. (ERT) for analysis of air quality policies neglected to mention two critical points, and therefore was misleading. First, in its original proposal to DOE, ERT included some 29 pages disclosing relevant projects it had undertaken in the past for public and private clients, even though DOE had not required such disclosure. Second, in comment on ERT’s work, Assistant Secretary Clusen testified that DOE had found no indication of bias in ERT’s work product and that DOE received full value for money paid. James R. Mahoney
Senior Vice-president Environmental Research & Technology, Inc. Concord, Mass. 01742
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