August 15, 2001

Ms. Madeleine Jacobs
Editor-in-Chief
Chemical & Engineering News
1155 - 16th Street, NW
Washington, DC 20036
edit.cen@acs.org

Dear Ms. Jacobs:

Your article "Testing Program Hits Snags" points out many of the complexities of testing for endocrine disruption, including the uncertainties regarding low-dose effects (July 30, 2001).

Unfortunately, rather than providing clarification, the EPA- and NIEHS-sponsored report of the low-dose peer review has further confused the science on low-dose effects. Your article quotes the Executive Summary of the report, stating "… the results were clear. The panel concluded that low-dose effects were demonstrated for estradiol and several other estrogenic compounds including diethylstilbestrol (DES), genistein (the phytoestrogen in soybeans), methoxychlor, and nonylphenol." The chemical industry challenged this wording in its response to the report since the panel of experts did not reach this conclusion. Indeed, the body of the report indicates that there is no clear evidence of low-dose effects, and certainly not for nonylphenol (NP), for which the text of the report (p. 51) states "The 'low-dose' of nonylphenol is questionable."

Part of the confusion arises because the EPA/NIEHS report did not consider the key questions raised in your article; specifically, whether low doses cause adverse effects and whether the dose-response curves are U-shaped. In fact, neither a U-shaped curve nor adverse effects at low doses has been demonstrated for NP. The "low-dose" effects that were cited for NP and other chemicals in the report were of uncertain significance for the health of the species tested; much less for human health. The effects, even if assumed to be biologically significant, were only observed at doses orders of magnitude higher than any human exposure and, hence, not "low doses" by any standard evaluation scheme.

Without rigorous reliance on the science, especially regarding low-dose effects, screening and testing efforts will waste resources and continue to produce equivocal and un-interpretable results that impugn the safety of numerous industrial chemicals, not just NP.

Sincerely,

Robert J. Fensterheim
Executive Director

 

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