NEWPORT BEACH : Chemical Level Cited in Reservoir Closure

Citing high levels of a suspected carcinogen in this city’s tap water, officials from the Metropolitan Water District plan to close the area’s 1-billion-gallon San Joaquin Reservoir on Monday and instead pipe in supplies from Yorba Linda.

The reservoir--which provides water to nearly all of Newport Beach and has offered backup supplies for Costa Mesa, Huntington Beach, Laguna Beach, Irvine and Dana Point--could be closed for three months, possibly longer, Metropolitan water quality director Ed Means said Wednesday.

Despite that decision, water from the basin poses no immediate health hazard and, so far, does not violate any federal or state water safety standards, Means said. But if the reservoir remains in use, “we have anticipated (it) would violate the standards” soon, he said.

Monthly tests at the reservoir have showed higher than normal counts of chemicals called trihalomethanes (THMs). The compounds are formed when chlorine, used generously in Newport’s open-air reservoir, mixes with organic material such as decayed leaves or with bromides, often carried in water from the Sacramento Delta region.

After receiving large doses of THMs, rats and mice have contracted bladder and kidney cancer, but Means described the risk to humans as slight. The risk would be significant only “if you drink two liters a day” of THM-laced water “over a lifetime,” he said.

Still, state and federal standards for drinking water limit concentrations of THM in drinking water to an average of 100 parts per billion for the year. And since April, counts at the reservoir have run as high as 150 parts per billion and higher, City Utilities Director Bob Dixon said. If these levels continued, officials expect that they would push the reservoir’s yearly THM count above allowable limits.

Rather than formally notify city residents that their drinking water was failing state standards, Metropolitan officials decided instead to shut the reservoir down.

Chemical contamination is just the latest in a string of problems at the 25-year-old, open-air reservoir. In recent years, Newport residents have plucked algae, midge larvae, brine shrimp, bird droppings and--in 1984, when African clawed frogs made the basin their home--frog parts out of their drinking water.

By October, the water district expects to finish a controversial environmental impact report on what to do with the reservoir. Options include building a treatment plant, abandoning it, or covering it. Officials acknowledged that nearby Spyglass Hill residents are fiercely opposed to having their aquatic views turned into a “55-acre trampoline.”