With 68 entries, commercial chemicals found in drinking water dominate the second list of 109 chemicals the EPA has published under its Endocrine Disruptor Screening Program (EDSP). The remaining 41 chemicals are pesticides; pesticides comprised the entirety of the first EDSP list, which was published in 2009. Under the EDSP, the EPA may require manufacturers, users, or importers of all chemicals in both lists to test for the potential of the substances to interact with the hormonal systems of humans and wildlife.
Three statutes
Under the Federal Food, Drug, and Cosmetic Act (FFDCA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the EPA has the authority to develop a chemical screening program to determine whether certain pesticides may have hormonal effects.
In addition, the Safe Drinking Water Act (SDWA) gives the EPA the power to require testing of any substance found in sources of drinking water if the Agency determines that a substantial portion of the population may be exposed to the substance. The drinking water contaminants on the second EDSP list include halogenated organic chemicals, dioxins, flame retardants polybrominated diphenyl ethers, polychlorinated biphenyls, perfluorocarbons (PFCs), plastics, bisphenol A, pharmaceuticals, and personal care products. The EPA must issue at least 25 orders per year for the testing of these chemicals.
The Agency says it intends to use its SDWA authority to order chemical testing in cases where the needed data cannot be obtained under FFDCA/FIFRA authority.
Potential to interact
In general, the EPA intends to use the data collected under EDSP, along with other information, to determine if a pesticide, chemical, or other substances have the potential to interact with the endocrine system. The final second EDSP list should neither be construed as a list of known or likely endocrine disruptors nor characterized as such, says the Agency.
The Agency also states that the determinations will be made on a weight-of-evidence basis. Specifically, chemicals that go through Tier 1 screening and are found to have the potential to interact with the estrogen, androgen, or thyroid hormone systems will proceed to the next stage of EDSP, where the intention is to determine which, if any, of the Tier 2 tests are necessary based on available data. Tier 2 testing is designed to identify any adverse endocrine-related effects caused by the substance and establish a quantitative relationship between the dose and that endocrine effect.
Modified policy
In addition to the second EDSP list itself, the EPA has issued modified policies and procedures to require Tier 1 screening for SDWA chemicals in the second list. According to the Agency, the modifications are intended to address issues that are unique to SDWA chemicals or to address circumstances where other competing considerations for SDWA chemicals warrant a modification of the FFDCA/FIFRA policies and procedures. Items addressed in the policies and procedures include who will receive EDSP test orders for SDWA chemicals, how the Agency will minimize duplicative testing, the process for contesting an EDSP test order, and the consequences for failure to respond to or comply with an EDSP test order.
The second EDSP list and the policies and procedures applicable to Tier 1 screening of SDWA chemicals were published in two documents in the June 14, 2013, FR.