cording to testimony from agency personnel (NRC, 2009), but these liaison positions were terminated because of resource constraints.
Despite the termination of liaison positions, NAWQA has continued to coordinate with EPA. For example, NAWQA made substantive contributions to EPA’s drinking water program in recent years. The 1996 amendments to the SDWA8 called for EPA to develop new approaches to evaluating contaminants, old and new, that may need to be regulated in drinking water to protect public health. EPA’s Office of Ground Water and Drinking Water is charged with developing a list of contaminants that may require regulation every 5 years, the Contaminant Candidate List (CCL), and developing a monitoring program, the Unregulated Contaminant Monitoring Regulation (UCMR). In addition, EPA must determine on a staggered 5-year deadline whether or not chemicals on the CCL warrant developing a regulation (the CCL-Regulatory Determination, or Reg Det process).
A key criterion for listing chemicals on the CCL and for the CCL-Reg Det process is whether the contaminant is known to occur or there is a substantial likelihood that the contaminant will occur in public water systems.9 Data on actual occurrence of unregulated chemicals in finished drinking water are difficult to obtain, and EPA’s authority is limited. The monitoring program (UCMR), for example, is limited in scope to no more than 30 contaminants every 5 years. Hence, NAWQA and USGS’ Toxics program monitoring data have provided important insights on unregulated contaminants in ambient waters and in the source waters for drinking water systems that have been used in the CCL, CCL Reg-Det, and UCMR development processes. In turn, NAWQA has reviewed the CCL as it considered which contaminants to include in its own monitoring schedules. Of particular note, during the past 5 years, EPA implemented a more rigorous process to develop the third CCL (CCL 3) (EPA, 2009a, 2009b; NRC, 2001). NAWQA collaboratively provided EPA with Cycle 1 monitoring data so that EPA could evaluate the data to meet its specific CCL requirements. NAWQA staff have provided technical assistance to EPA programs as well as data for the Six-Year Review of regulated chemicals (EPA, 2009c). Despite this record of success, in testimony EPA representatives called for greater documentation and transparency in the selection of analytes to be monitored by NAWQA.
NAWQA data and cooperation have also contributed to the continuing efforts of EPA to meet the goals of the Clean Water Act. NAWQA occurrence data have been important to the prioritization of contaminants for development of water-quality criteria and aquatic life criteria by the Office
8 Section 1445(a)(2); see 42 U.S.C. 300.