ACWA Releases New Study on Water Supply Impact of U.S. EPA's Arsenic Proposal; Regulation Could Jeopardize Groundwater Projects.

Business & News Editors/Environment Writers

SACRAMENTO, Calif.--(BUSINESS WIRE)--Nov. 10, 2000

The Association of California Water Agencies (ACWA) today released a new study examining the potential impact on groundwater supplies resulting from the U.S. Environmental Protection Agency's (EPA) proposal to reduce the standard for arsenic in drinking water. The study examines how the EPA's proposed reduction in arsenic levels, from the current 50 parts per billion (ppb) down to 5 ppb, will impact government projections on the increased yield from conjunctive use groundwater projects.

"It appears that the U.S. EPA's current arsenic proposal is moving down a path that is contrary to that of the CALFED Bay-Delta Program and other agencies working to expand water supply through groundwater projects," said ACWA Executive Director Steve Hall. "We're very concerned about California getting hit with this rule's unintended consequences."

Conjunctive use projects mix surface water with groundwater, and provide an average of 40% of California's total water supply. As the demand for water increases in California, many agencies -- including the high-profile CALFED Bay-Delta Program -- are focusing on conjunctive projects to increase supply. If, however, the U.S. EPA's arsenic rule moves forward as proposed, many of those projects could be in jeopardy.

In the ACWA study, researchers collected arsenic data from throughout the state and compiled it by county and groundwater basin. The locations of selected groundwater conjunctive use sites were then compared to the average arsenic concentration within each basin. The study found that all of the sites are located in areas where the average existing arsenic levels are at or above the proposed MCL of 5 ppb.

"It is likely that some conjunctive use management projects capable of increasing water supply reliability in California may not be implemented because of excessive investigation and/or treatment costs as a result of a 5 ppb arsenic standard," according to the report.

Arsenic is a naturally occurring substance that is sometimes found in groundwater. The U.S. EPA is required to revise the standard for arsenic every 10 years, but in its recent proposal, has proposed reductions which ACWA estimates will impose more than $1.7 billion in initial capital costs nationally, in addition to putting many groundwater projects out of reach. Worse, the EPA's own Science Advisory Board, or SAB, has criticized the proposal, saying that reducing arsenic levels to this level will not provide meaningful public health benefits.

ACWA member agencies have conveyed these concerns to U.S. EPA, and reminded the agency that monitoring for arsenic at or below 5 ppb is beyond the reach of most districts' existing sampling technology. U.S. EPA is required to finalize its rule for arsenic in drinking water during 2001.

ACWA is a statewide organization whose 439 public agency members are responsible for about 90% of the water delivered in California. For more information, visit ACWA's Web site at www.acwanet.com.