House Subcommittee Holds Hearing on Endocrine Disrupting Chemicals in Drinking Water

On February 25, 2010, the House Committee on Energy and Commerce Subcommittee on Energy and Environment held a hearing entitled “Endocrine Disrupting Chemicals in Drinking Water: Risks to Human Health and the Environment.” The Subcommittee intended the hearing to examine the science and regulation of endocrine disruptors that may be found in sources of drinking water. Witnesses included:

• Jim Jones, Deputy Assistant Administrator, Office of Prevention, Pesticides and Toxic Substances, U.S. Environmental Protection Agency (EPA);
   
• Linda S. Birnbaum, Ph.D., D.A.B.T., A.T.S., Director, National Institutes of Environmental Health Sciences;
   
• Gina Solomon, M.D., M.P.H., Senior Scientist, Natural Resources Defense Council; and
   
• Christopher J. Borgert, Ph.D., President and Principal Scientist, Applied Pharmacology and Toxicology, Inc.

The witness testimony is available online.

Subcommittee members criticized the slow pace of EPA’s Endocrine Disruptor Screening Program (EDSP). The Food Quality Protection Act of 1996 directed EPA to develop a screening program for endocrine disruptors, and EPA created the EDSP. The EDSP will use a two-tiered screening process: Tier 1 will identify chemicals that have the potential to interact with the endocrine system; and Tier 2 will determine the endocrine-related effects caused by each chemical and obtain information about effects at various doses. On April 15, 2009, EPA issued the final list of 67 chemicals selected for Tier 1 screening, and began issuing test orders in October 2009. Jones stated that EPA is still working to validate the Tier 2 assays, and that it expects to do so by 2012.

Jones testified that, under the Safe Drinking Water Act (SDWA), EPA has the authority to test substances that may be found in sources of drinking water to which a substantial population may be exposed. According to Jones, EPA is preparing a list of no less than 100 chemicals, “a draft of which will be released shortly.” The list will be drawn from three sources: National Primary Drinking Water Regulations (NPDWR); the Contaminant Candidate List 3 (CCL 3); and pesticides that are on the reregistration schedule for 2007 through 2008. CCL 3 is a list of contaminants that are currently not subject to any proposed or promulgated NPDWRs, that are known or anticipated to occur in public water systems, and which may require regulation under SDWA. CCL 3 includes pesticides, other chemicals used in commerce, and disinfection byproducts and degredates.

Birnbaum emphasized four aspects of exposure to endocrine disruption:

• The effect of low doses: Normal endocrine signaling involves very small changes in hormone levels, yet these changes can have significant biological effects;
   
• The wide range of effects: Endocrine signals govern virtually every organ and process in the body;
   
• The persistence of effects: The effects of exposure to endocrine disruptors can be observed long after the actual exposure has ceased; and
   
• The ubiquity of exposure: Both naturally occurring and manmade substances can be endocrine disruptors.

According to Solomon, there are two opportunities to address endocrine disrupting chemicals: (1) many chemicals have never been adequately tested for their toxicity, including their endocrine effects; and (2) some of the chemicals in our water supply are known endocrine disruptors and can alter hormone function and disrupt development, even when they are present in very dilute concentrations. Solomon noted that, under the SDWA Amendments of 1996, EPA was to develop an endocrine disruptor screening program by August 1998, implement the program by August 1999, and report on the program’s progress by August 2000. Solomon testified that known endocrine disruptors in drinking water include perchlorate, chemicals used in plastics, and steroid hormones. Solomon recommended that EPA take the following steps to address the issue of endocrine disruptors in drinking water:

• Implement testing under the EDSP for priority drinking water contaminants, including all chemicals on the CCL 3, as well as other chemicals in pharmaceuticals and personal care products that have been detected in surface or groundwater;
   
• Implement aspects of the Endocrine Disruptor Screening and Testing Advisory Committee report that have been ignored;
   
• Evaluate and identify wastewater and drinking water treatment practices for removing endocrine disrupting chemicals, including pharmaceuticals; and
   
• Work with other federal agencies and states to prevent or limit the use of hormones in agriculture.

Solomon recommended that Congress take additional steps, including:

• Require EPA to prioritize and screen chemicals in drinking water, including mixtures, for endocrine disrupting effects;
   
• Restore adequate funding for the U.S. Geological Survey (USGS) Toxic Substances Hydrology Program and the USGS National Water Quality Assessment Program, so more data are available on contaminants in source water and drinking water; and
   
• Reform the Toxic Substances Control Act (TSCA) to require testing of chemicals for toxicity, and require EPA action to regulate promptly hazardous chemicals.

Borgert emphasized the need for EPA and Congress to base any actions on sound science. Borgert outlined three fundamental tenets to which data must conform to be considered an established scientific observation:

1. The identity and authenticity of scientific measurements must be verifiable within a defined range of precision;
    
2. Measurements and observations must not be confounded by extraneous factors and influences known to corrupt their accuracy and precision; and
    
3. The measurements and observations must be replicable in independent hands.

It is not entirely clear what impact, if any, the hearing will have on the EDSP. It is clear Members are troubled by what they regard as the slow pace of the program. As Congress is seldom in touch with the scientific challenges as ambitious a program as the EDSP present, it is not surprising it reacted as it did.

The testimony received here is likely to be parallel if not identical to the perspectives that will be offered as Congress debates any proposals for legislative amendments to TSCA. The continued rhetorical drumbeat about the paucity of chemical test data will further complicate any eventual discussion about the most appropriate way to test and evaluate the existing chemical universe. This will likely lead to calls for a blanket approach to chemical testing — e.g., test “all” chemicals for endocrine or other prescriptive effects — which will reduce the discretion given to EPA or other agencies to discriminate among chemicals or exposure scenarios. Unfortunately, if this path is followed to an extreme, requirements for quick action regarding new chemical testing will likely fail or at least be impeded by the sheer size and magnitude of such new programmatic requirements.