wide benefits from the Guidance. Smith compared only these estimated cancer risk reduction benefits to basinwide cost estimates to construct his cost-benefit ratio, omitting other relevant benefit categories. Smith calculates the alleged "error" in EPA's benefits estimates by comparing the values EPA used to his own estimates, which are derived from faulty analysis of limited data. The following are the major sources of error in Smith's critique. 1. Smith attributes a 310% "error" to EPA's overestimated fish consumption rate. In calculating his "error," Smith excluded tributaries to the Great Lakes and used a 25% edible fish yield when study results show yields as high as 50%. 2. A 250% "error" is attributed to EPA's use of concentration data based mostly on lake trout, Smith asserts. However, no lake trout data were used for Lake Erie and for Ontario and Superior lake trout data were not used for all pollutants. 3. A 200% "error" resulted, according to Smith, because EPA assumed steady state for non-steady state conditions. Whether fish concentrations are in steady state for all contaminants regulated by the Guidance is unknown. EPA accounted for the lag in realization of benefits by using 10- and 20-year phase in periods for benefits. 4. Smith attributes a 630% "error" to EPA's overestimate of total loadings from point sources. To arrive at this result, Smith compares total (nonpoint and point) loading estimates of DDT from one study conducted in the mid-1980s to point source estimates derived in the mid-1990s. 5. A 3200% "error" was attributed to EPA's use of an overly protective cancer slope factors (CSFs). CSFs are developed and applied as standard methodology used by EPA in the estimation of risks, and are intended to be protective of human health. Note that recent research indicates that PCBs, dioxin, organochlorine pesticides, and other chemicals may have reproductive and developmental toxicity through processes such as endocrine disruption. In addition to considering the problems noted above with Smith's interpretation of the whole watershed analysis, it is even more important to recognize that the more appropriate evaluation is the case study assessment. For these more complete benefits analyses, Smith
observes benefits that are commensurate with costs. Moreover, human health benefits, on which his criticisms are focused, constitute a limited portion of total benefits for the case studies. A detailed rebuttal of Smith's article can be found on the World Wide Web (http: / /www.epa.gov/OST/Events/ glakes.html) or by calling Mark Morris at (202) 260-0312. E. CASTILLO, M. MORRIS, R. RAUCHER, M. BARRON, J. PARKER Hagler Bailly Consulting, Inc. Boulder, CO 80306-1906 Dear Editor: Daniel Smith advocates in his recent Policy Analysis paper that the Great Lakes Water Quality Initiative (GLI) "should be reconsidered as its costs will likely dramatically exceed its benefits." His objections to the GLI coincide with his funder's, the Occidental Chemical Corporation. Unsuccessful in opposing EPA's final approval of the GLI in 1995, industry groups are attempting to block the GLI in federal court and weaken required implementation by the eight Great Lakes states. Having insisted that cost-benefit analysis must be part of the regulatory process industry representatives now exploit inherent weaknesses in such analyses Smith accepts EPA's estimates of compliance costs for the GLI of $60 million to $380 million per year. In 1995, however, Smith endorsed claims that the GLI "could cost billions of dollars annually" [ES&T 1995, 29, 42A). Such fanciful claims were sharply criticized as excessive by the state of Michigan in a letter from Department of Natural Resources Director Roland Harmes to EPA (Sept. 8, 1993), which concluded that "the cost of implementing the GLI in Michigan at existing facilities will not be significant " Smith laboriously dissects many of EPA's assumptions regarding its benefits analysis, especially those benefits attributed to cancer risk reduction. Context is ignored: The GLI's "principal benefits," EPA points out, are indirect and difficult to forecast because they occur in the future and are largely ecologic in nature. Smith notes that the Michigan Environmental Science Board (MESB) concluded that EPA's default methods probably overestimate cancer risks from consuming PCB-contaminated fish. The same report, however, stresses risks of noncancer endpoints, particularly the "higher
vulnerability of the fetus to the neurobehavioral effects of PCBs" (MESB, Lansing, Mich., September 1995). Recent studies elevate this concern. These findings have caused EPA and the U.S. Department of Health and Human Services to warn Michigan Governor John Engler that the MESB report likely underestimates public health risks from exposure to Great Lakes pollutants in fish (letter from Perciasepe, R. et al., Oct. 9, 1996). The findings heighten the importance of securing all feasible reductions in releases of persistent toxic pollutants. To critique the GLI based primarily on a scrutiny of cancer risks overlooks benefits impossible to quantify, including pollution prevention, ecologic improvement, protection of cultural heritage, and reduction in noncancer endpoint health risks. Congress enacted the GLI in 1990 to ensure that the Clean Water Act conforms with our commitments in the U.S.-Canada Great Lakes Water Quality Agreement of 1978. Our nation's policy is that "the discharge [into the Great Lakes system] of any or all persistent toxic substances be virtually eliminated." In 1986, governors of the eight Great Lakes states endorsed this goal and a commitment "to continue reducing toxics in the Great Lakes Basin to the maximum extent possible " These public policies express values that transcend myopic cost-benefit analysis. The people of the Great Lakes region have decided that the GLI is consistent with these values. WAYNE A. SCHMIDT Great Lakes Natural Resource Center National Wildlife Federation Ann Arbor, MI 48104 Author's Response I share the goals of EPA to protect the Great Lakes. It is in this spirit that I have called for more rigorous peer review of EPA's work to promote "an open and honest attempt to value" the worth of the GLI. Based on my review of the GLI, it is clear that EPA has placed undue focus on toxic chemicals, especially the toxicologically negligible masses emanating from point sources. The unfortunate result is that much more pressing environmental and human health concerns are being neglected at the federal level In response to the assertion by Castillo et al. that my review "placed undue focus on the 'whole-water-
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shed' study," I subjected the entire benefits analysis to the same detailed review but focused on the whole-watershed study for reasons already stated there and reiterated below. My examination of the subwatershed case studies found repetitive inaccuracies and faulty reasoning similar to that demonstrated in review of the whole watershed study. I have never as Castillo et al. assert, "observe [d] that benefits are commensurate with costs" for the subwatershed case studies. Given space limitations, the ES&l article focused on the whole-watershed analysis for the following reasons. First, it deals with reductions of risk to human health and is therefore representative of almost all estimated benefits which are directly or indirectly based on reducing risks to human health. About 96% of the benefits for the Green Bay subwatershed were based, directly or indirectly, on reductions in human cancers and other risks. No appreciable benefits can occur across the watershed unless there are significant reductions in human health risk Second, analysis of the whole watershed study was used to illustrate problems found throughout the document. Benefits in the sub-watershed case studies were also based on serious, repetitive errors that inflated benefits. Again using the Green Bay analysis as an example: EPA based its benefits on a point source allocation for PCBs (9.4% of total loading) that is widely known to be incorrect based on EPA's Green Bay Mass Balance Study (Velleux, M.; Edicott, D. /. Great Lakes Res. 1994 20 416-34). The following are rebuttals to the points made by Castillo et al. 1. Overestimation offish consumption. My method of calculating average fish concentrations is supported by four binding, external peer reviewers and by common sense. Neither can be said for EPA's method: basing average exposure on abnormally contaminated fish. The error analysis is relatively insensitive to inclusion of tributary fish, since inclusion of tributary fish reduces the error due to overestimation of fish consumption but increases the associated with inapplicability of lake trout concentrations and the error associated with point source contribution 2. Most Lake Michigan concentrations based on lake trout. For Lake Michigan, the following represent
the concentration values from lake trout versus total number of values used: 2 of 2 values for PCBs; 3 of 4 values for chlordane; 2 of 2 values for DDT; 3 of 4 values for dieldrin, 0 for 1 values for hexachlorobenzene; and 1 of 1 value for toxaphene. Error analyses for other Great Lakes would find similar total errors as that found for Lake Michigan. 3. Assuming steady state for nonsteady state conditions. Three relevant EPA-sponsored studies were available to address the degree of non-steady state in Great Lakes systems. Estimated levels of non-steady state were 200% for Green Bay water, about 380% for Lake Michigan fish, and about 300% for Lake Ontario fish. 4. Point source allocations overestimated. Castillo et al. claim that my method is a "faulty analysis based on limited data." My method is the same method employed in EPA's benefits analysis minus the highly questionable assumption that cadmium, lead, and mercury could serve as surrogates for the banned organochlorine pesticides. My original manuscript considered that any reduction in total external loading of DDT was probably canceled out by the overestimation of current point source loading. This information however WAS deleted from the final article due to space constraints 5. Misuse of CSFs as predictors of likely events. Recent EPA guidance documents on risks of chemicals in fish (EPA, Office of Water, 1995, 823B-94-004) state: "This [CSF] method provides an upper estimate of risk; the actual risk may be significantly lower and may be as low as zero. It is important to recognize that the use of this model results in risk estimates that are protective, but not predictive of cancer incidence." [Italics added.] Since the goal of the benefits analysis is quoting Ccistillo et til cin "accurate assessment of benefits that be expected" (i e are likelv) CSFs cannot be used as predictors Readers are encouraged to comment on articles published in ES&T and on other issues facing the environmental community. Contributions are limited to 500 words. Send contributions to the Managing Editor within two months of the date of publication of the original article. Submissions are subject to editing for clarity and length. Send letters to ES&T, 1155 16th St., N.W., Washington, DC 20036, or via e-mail to
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