To facilitate the collective interpretation of multiple studies, EDSP Tier 1 screening data were conceptually organized around hypothesized modes of action (e.g., altered receptor signaling, altered hormone synthesis, altered neuroendocrine axis function) in "estrogenic," "antiestrogenic," "androgenic," "antiandrogenic," and "thyroid-active" pathways (EDSTAC 1998; U.S.
Together, the EDSP screening and testing strategy links mechanistic data to apical end points and is a unique regulatory program designed around a toxicological mode of action framework (EDSTAC 1998; U.S.
EPA's proposed Endocrine Disruptor Screening Program substantially reflects the EDSTAC recommendations.(114) Particularly, EPA agreed to expand the scope of the testing program beyond the FQPA and SDWA provisions to include a wide range of chemicals to which Americans are exposed.(115) After initial screening and priority setting, EPA plans to promulgate its first test orders under its FQPA and SWDA authority in late 2001.(116) Additionally, "EPA may propose a TSCA test rule to require screening of chemicals that may not be covered by the FFDCA/SDWA.
(38) EPA's Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) defined "endocrine disruptor" as "an exogenous chemical substance or mixture that alters the structure or function(s) of the endocrine system and causes adverse effects at the level of the organism, its progeny, populations, or subpopulations of organisms, based on scientific principles, data, weight-of-evidence, and the precautionary principle." ENDOCRINE DISRUPTOR SCREENING AND TESTING ADVISORY COMM., supra note 36, at ES-1.
Though the legislation instructed EPA to screen pesticides and drinking-water contaminants, EDSTAC recommended that the agency do more: screen all industrial chemicals.
Because "it is not likely to be possible" to screen all of the remaining 62,000 chemicals, EDSTAC advised EPA to prioritize them for testing on the basis of their pervasiveness or their potential for high exposure in identifiable populations or ecosystems.
At a Boston meeting of the American Chemical Society last week, Timm described the strategy proposed by EDSTAC. It relies on a two-tier process.
EDSTAC hopes that two of those assays can be done in a rapid, automated fashion.
The recommendations of EDSTAC
have served as the basis for the U.S.
[Endocrine Disruptor Screening and Testing Advisory Committee).
Thomas Zoeller of the University of Massachusetts Amherst, who was a member of EDSTAC
, calls a "regulatory pulse." In contrast, thyroid product levels "stay pretty much the same all the time," and if disturbed will attempt to return to normal levels.
segments of the population are exposed," including human milk (EDSTAC
1998), which has raised questions regarding whether appropriate methods and data are available for performing such an assessment (LaKind and Berlin 2002).