Study Finds Nitrates Are Influencing Bay

An estimated 12,000 pounds of nitrates flowing daily into the Upper Newport Bay wildlife reserve have caused an explosive growth of plankton and algae that has given the water its murky brown color, according to a study by a Newport Beach physician.

The main sources are fertilizer-laden runoff from three Orange County wholesale nurseries, agricultural runoff from water-intensive crops and reclaimed sewer water discharged by the Irvine Ranch Water District, Dr. John F. Skinner said.

Nitrates in the bay water pose no threat to public health or to wildlife, biologists say.

High concentrations of nitrates and phosphates have been blamed for the death of aquatic life in freshwater lakes and rivers. In a process known as eutrophication, the overstimulated plant and algae life eventually uses up all the oxygen needed by other organisms.

Reduces Diversity

The process is not considered deadly to saltwater bays and estuaries because daily tidal flushing dilutes and washes away much of the chemicals. However, biologists say excessive levels of nitrates may reduce the diversity of marine life in Newport Bay, favoring filter-feeding fish like mullet and anchovies over the sport fish historically there.

For Skinner, a water sport enthusiast who has been active in bay pollution studies in recent years, excessive plant growth makes even the lower bay an unpleasant place to swim or boat.

“I think the most disconcerting thing to the public has been the dirty look of the water, but many residents have been bothered by nuisance growth of filamentous algae and sea lettuce around boat docks and boats,” Skinner said Wednesday.

Skinner said water samples gathered during the month of January from points along tributaries feeding into Newport Bay showed high concentrations of nitrate fertilizers in runoff from three large wholesale nurseries.

The three are the El Modeno Gardens, Hines Wholesale Nurseries and Bordier’s Nursery, all of which operate in the foothills northeast of Irvine.

Thousands of Pounds

The samples, tested in a county laboratory, indicated concentrations of nitrates averaging as high as 400 milligrams per liter of water, and in some cases reaching much higher, Skinner said. Depending on the volume of water flowing into the bay’s main tributary, San Diego Creek, the amount of nitrates flowing daily could average more than 3,000 pounds from each of the nurseries.

He said the practice of mixing nitrate-rich chemical fertilizers with water as the nursery plants are irrigated causes runoff of almost 50% of the water and fertilizers.

Elsewhere in California, Skinner said, nurseries are being required to capture and reuse irrigation runoff, and he suggested in a recent meeting with representatives of the county, regional water quality officials and the Irvine Co. that such practices be adopted in Orange County.

Officials for the nurseries could not be reached for comment on their fertilizer practices.

Bob Collacott, head of the county Environmental Management Agency’s environmental services section, said Skinner’s results generally coincide with county studies of nitrate levels conducted over the last decade.

“We have determined that the concentrations we are seeing are not associated with urban development,” Collacott said.

He said samples from San Diego Creek have shown concentrations of 80 to 150 milligrams per liter of water. By comparison, nitrate levels from urban runoff in western Orange County are about five milligrams per liter.

Sat Tamaribuchi, director of water, waste and energy for the Irvine Co., said concern over high nitrate flows into Newport Bay in recent years prompted a change in fertilization and irrigation practices on company crops.

Tamaribuchi said fertilizers are now being applied at the time of planting and also under the plants in an effort to maximize their effectiveness and reduce runoff.

Two of the nurseries--Hines and El Modeno--lease their property from the Irvine Co.

Will Urge Reduction

Tamaribuchi said they were “a significant source” of nitrates flowing into the bay and said Irvine Co. officials will urge them to “start looking at alternative ways that would reduce the amount of runoff.”

The third nursery, Bordier’s, leases its property next to the El Toro Marine Corps Air Station from the military. According to county and regional water quality officials, the nursery may already be preparing to build a system that would capture and reuse runoff water.

In the case of the Irvine Ranch Water District, Skinner said, concentrations of nitrates sampled at the base of its reservoir in Sand Canyon averaged about one-tenth of that from the nurseries.

However, he said, the district’s greater volume of flow makes its nitrate contributions greater than actual concentrations would suggest. According to Skinner’s calculations, the water district could be sending more than 2,500 pounds of nitrates daily into the bay during the winter months that it discharges water from the Sand Canyon Reservoir.

Discharges Discounted

Water district officials, who were disturbed that they have not yet received Skinner’s results, said levels of nitrates monitored at the district’s treatment plant in Irvine are far lower than Skinner’s findings and suggested that animal droppings entering the reservoir could explain the discrepancy.

Board Chairman Peer Swan said the district’s discharges cannot be contributing to the algae problem in the bay because they occur during winter months when the plants are dormant.

But Carl Wilcox, manager of the wildlife refuge for the state Department of Fish and Game, said that is not necessarily the case. This winter has been so mild, plant growth has merely slowed, not stopped, he said.

Skinner’s biggest concern is that the Irvine Ranch Water District is more than a year behind in construction of a pipeline link that would eliminate all but emergency flows.

Keith Lewinger, assistant director of planning for the district, said the agency had been tied up in debate over how to expand its sewer treatment capacity. Until the decision was made recently, he said, it was impossible to begin construction.

To Stop All Discharge

By next winter, when the water district’s system finally is linked with the Orange County Sanitation Districts’ ocean outfall off Huntington Beach, the district will stop all discharge from Sand Canyon except during heavy rainfall, Lewinger said.

James Bennett, executive officer for the Santa Ana Regional Water Quality Control Board, said that while bacteriological and chemical pollution problems in the bay have been a higher priority for his staff, they have prodded Irvine Ranch Water District to get its plant improvements under way and have threatened not to renew its discharge permit out of concern for water quality.

Now that the water district issue appears resolved and agricultural interests are set to begin a voluntary search for solutions, Bennett said he was hopeful there would be a major reduction in nitrates entering the bay by the end of this year. A third phase of a massive silt-removal project in the bay scheduled to begin this spring also will help.

“Everything is beginning to fall into place,” Bennett said. “The key to this whole thing is . . . if we can get people to cooperate, things will be improved.”

No one is certain how much the nitrate flows must be reduced to restore the bay. Wilcox and county biologists say improvement could take years and the water clarity may never be fully restored.

But Skinner, who stopped long-distance swimming in the bay more than eight years ago because it was “impossible to see more than two feet ahead of me,” said, “if it’s possible to improve the appearance of our water--even if it isn’t a health threat now--we should do it.”