EPA releases list of endocrine-disrupter candidates
A long-awaited list leaves much to be desired, say many stakeholders.
In mid-June, the U.S. EPA released its much-anticipated draft list of compounds to screen for endocrine disruption. The long-overdue list, which should have been completed in 1999, includes known and suspected endocrine disrupters, and all substances are pesticides selected because of their potential for human exposure and their high production volumes. The compounds were not chosen because they are suspected endocrine disrupters, EPA emphasized.
The draft list contains 73 substances: 69 pesticides and 4 inerts used in pesticide formulations. More than half of the compounds have known effects on the endocrine system or have proven antiandrogenic or estrogenic activity.
Theo Colborn, a longtime endocrine disruption researcher and activist, calls the list “unbiased” because to her it appears that EPA didn’t favor business interests. But she adds that “the whole thing is a waste.” Colborn and many others who participated in EPA’s decadelong process to select compounds and create a testing protocol for endocrine disrupters are disappointed in the choices EPA has made on assays and other issues and in the compounds that didn’t make the list.
Sarah Janssen of the environmental group Natural Resources Defense Council (NRDC) notes that pesticides were expected on the draft list, but she asks, “Why are they including things that are obviously endocrine disrupters? Why put them through a screening and waste precious resources and time on something we already know is an endocrine disrupter?”
Mark Maier, a toxicologist and health science policy manager with the pesticide industry trade association CropLife America, agrees. “There are really no surprises on the list,” he says, referring to pesticides with the potential for exposure, but “the screening tests are redundant” and “unnecessary” because the pesticide manufacturers already test their products more comprehensively than any other industry does, including pharmaceuticals. “In some cases, endocrine activity may not be directly attributable to the parent compound” but instead to its metabolites, for example, Maier says, “so it could be missed by screening.” He adds that no unknowns appear on the list. “The program evolved through a political process, not a scientific process,” he says.
Even so, EPA will not call these substances endocrine disrupters until they have gone through the agency’s entire testing battery, a series of assays that some critics say are not sensitive enough to detect low-dose exposures. In addition, Janssen says that people are exposed to “six or seven phthalates on a daily basis that act together. . . . It doesn’t make sense for EPA not to look at them as a mixture.”
But mixtures testing is not yet in the mix, and EPA continues to delay work on the simpler single-compound tests. So far, only two tests have been validated—uterotrophic and Hershberger assays—both of which are considered old standards by scientific measures. EPA’s Linda Phillips, who leads the testing program, says that if validation and peer review go well, she hopes to see all the screening tests online by 2008, but the agency’s past delays have bred skepticism among all of those who have met with and advised the agency.
“All this effort, all this time spent in over 10 years, there’s been amazingly little progress made, and yet the agency expects to have all these tests wrapped up, validated, and ready for use by companies by 2008,” says James Stevens, who is a former Syngenta research scientist and professor at Wake Forest University and who participated in several of the EPA advisory committees in the past. Stevens says that the tests currently being required by EPA are more than sensitive enough to determine whether a substance is an endocrine disrupter.
Maier says little has been accomplished since the discussions over endocrine disrupters began in earnest, leaving companies and other stakeholders to make the same arguments they made 10 years ago. He is looking to July, when EPA releases its implementation policy, which should lay out how EPA will propose who will pay for future research on specific compounds.
NRDC’s Janssen says EPA should move on to other compounds immediately. Drinking-water contaminants that aren’t on the draft list—nonylphenols and octaphenols in particular—have “widespread potential for human exposure and are already having wildlife effects,” she points out.
But the second list of candidate screening compounds remains far off in the future, after the agency establishes its testing protocols. And even if EPA does so by the end of the year, Colborn argues, the procedure may never be adequate: “The endocrine system is so complex that you can’t say, ‘This is a safe product,’” perhaps no matter how many of the current tests it passes.
