Laws / Regulations

Human Health Water Quality Criteria for Polychlorinated Biphenyls (PCBs) in the National Toxics Rule (NTR)

Summary of Final Rule Revision

EPA-822-F-99-003; September 1999

The U.S. Environmental Protection Agency is revising the human health water quality criteria for polychlorinated biphenyls (PCBs) in the National Toxics Rule. When the National Toxics Rule was adopted, human health criteria for PCBs were calculated using the cancer potency factor entered in the Agency's Integrated Risk Information System (IRIS). The Agency, is revising the human health water quality criteria for PCBs in the NTR, based on the Agency's reassessment of the cancer potency of PCBs.

Background

On December 22, 1992, EPA finalized the National Toxics Rule (NTR), which established numeric water quality criteria for priority toxic pollutants for fourteen States and jurisdictions. This federal rule brought these States into compliance with section 303 (c)(2)(b) of the Clean Water Act.

Human health water quality criteria for polychlorinated biphenyls (PCBs) were included in the 1992 final National Toxics Rule. A number of parties challenged the human health criteria for PCBs. As part of a partial settlement agreement with the General Electric Company, EPA is now revising the human health water quality criteria for PCBs in the NTR. These changes are based on the Agency's reassessment of the cancer potency of PCBs.

In the National Toxics Rule, human health criteria for PCBs were calculated by entering a cancer potency factor of 7.7 per mg/kg-day into the Agency's Integrated Risk Information System (IRIS). EPA recently reassessed the cancer potency of PCBs, and issued a final report, PCBs: Cancer Dose-Response Assessment and Applications to Environmental Mixtures. EPA now adopts an approach that distinguishes among PCB mixtures by using information on environmental mixtures and different exposure pathways. Based on this reassessment, EPA derived the new human health criteria for PCBs by using a cancer potency factor of 2 per mg/kg-day. This potency factor is considered protective of children and adults who drink surface water and eat fish from water contaminated with PCBs. The revised NTR human health criteria for PCBs are both 0.00017 ug/L for protection of human health from consumption of aquatic organisms and water, and consumption of aquatic organisms only.

Costs and Benefits

Water quality criteria alone do not directly impose economic impacts. However, regulated entities may incur costs when the water quality criteria that are used to develop State water quality standards are translated into NPDES permits. Since the revised human health criteria for PCBs are less stringent than those published in the 1992 National Toxics Rule, States or jurisdictions who implement NPDES permit limits with the new criteria, may reduce costs associated with meeting the new criteria.

Additional Information

For additional information concerning this final rule, contact Cindy Roberts, Office of Science and Technology, Health and Ecological Criteria Division (4304T), 1200 Pennsylvania, N.W., Washington, D.C., 20460.

You may view the Federal Register notice that describes this final rule or request a copy from the National Service Center for Environmental Publications at 1-800-490-9198. The final rule includes complete information on how to review the administrative record for this rule.