COLUMBUS, Ohio, August 31, 1998 -- States revising water quality standards should pair biological and chemical sampling to determine the most environmentally protective -- and scientifically rational -- limit for a dissolved metal such as copper in wastewater effluent, according to a presentation at a meeting sponsored by the U.S. Environmental Protection Agency (EPA) Office of Water.

Rob Reash, senior biologist, environmental services - water quality for American Electric Power (NYSE: AEP), spoke at EPA´s "Meeting on Water Quality Standards, Water Quality Criteria and Implementation, Including Water Quality-Based Permitting" in Philadelphia recently. Reash reported on data he and AEP environmental engineer Jeff White have collected since 1994 at AEP´s Muskingum River Plant on the lower Muskingum River in southeast Ohio.

Their study compared the biological effects of dissolved copper discharged to the river at the discharge point and at three progressive downstream points to a point upstream. Reash placed Hester-Dendy artificial substrate samplers -- "bug condos" -- at the five points in the river, then collected them after six weeks. The samplers were sent to a lab, which culled the organisms that collected in the "condos," identified the organisms and counted them. The results were used to assess the effects of the copper on nearby aquatic life.

"We wanted to see any difference between the upstream location where there would be no effects of the discharge, and at points downstream," Reash said. "We were looking specifically at the immediate impact at the discharge point, and at locations where we would expect to see recovery if adverse effects were actually observed near the discharge point.

"Although measured copper levels were twice as high near the discharge compared to an upstream reference site, five of the six aquatic life indicators showed a more diverse, or at least as diverse, community at the discharge site," Reash said. "Copper-sensitive organisms, specifically mayflies and caddisflies, were just as abundant at the discharge point compared to upstream.

"The approach we used is simple. It integrates the highly site-specific interactions of chemical exposure and biological response. Such paired biological and chemical sampling can remove much of the uncertainty in assessing whether biological response is, or is not, associated with chemical exposure in the water."

Ohio EPA adopted dissolved metals criteria for water quality standards statewide in Nov. 1997. Previously, total metals had been the standard.

"A total-metal measurement approach ignores the fact that not all metal in water is potentially toxic -- or bioavailable -- to the aquatic life," Reash said. "The dissolved metal approach is a superior method to estimate actual potential environmental impact, and gives you a scientifically based standard that will be feasible, defensible and more readily acceptable."

Reash added, "Our study supports AEP´s long-standing position on state implementation of water quality standards. First, states should replace total-metals water-quality criteria with dissolved-metals criteria. Second, site-specific biological data should be regarded as the final arbiter or water quality, as opposed to simple chemical measurements or effluent toxicity tests in the laboratory. EPA should give states the flexibility to regard biological data as the true test of water quality impairment, if such information is available."

At AEP´s Muskingum River Plant, consisting of five electricity-generating units with a capacity of 1,425 megawatts, the primary source of copper in effluent is a closed-cycle cooling system. Water circulating through heat-exchange condenser tubes in the tower slightly corrodes the tubes, releasing copper to the water. The copper concentrates over time, as the water recycles through the closed-loop system. Some of this water has to be replaced periodically because the buildup of dissolved solids on the condenser tubes will inhibit the efficient transfer of heat. The spent recycled cooling water, which is discharged to an ash treatment pond, is called cooling tower blowdown.

AEP measured the total copper and dissolved copper in the ash treatment pond effluent at a point before it is discharged into the Muskingum River. The ash pond effluent is subject to water quality-based effluent limits set by state and federal regulations.

AEP, a global energy company, is one of the United States´ largest investor-owned utilities, providing energy to 3 million customers in Indiana, Kentucky, Michigan, Ohio, Tennessee, Virginia and West Virginia. AEP has holdings in the United States, the United Kingdom, China and Australia. Wholly owned subsidiaries provide power engineering, energy consulting and energy management services around the world. The company is based in Columbus, Ohio. On Dec. 22, 1997, AEP announced a definitive merger agreement for a tax-free, stock-for-stock transaction with Central and South West Corp., a public utility holding company based in Dallas.