Spill Keeps Part of Mission Bay Closed

A large section of Mission Bay remained closed Friday after a spill earlier in the week poured 2,000 gallons of sewage sludge into a Fiesta Island cove.

County health officials said the eastern waters of the bay between the island and the mainland as far north as the Mission Bay Visitors Center will remain under quarantine at least through the weekend.

John Melbourn, county public health engineer, said that conclusive results from his department’s tests of the bay water have not been obtained and that the extent of contamination is not known.

But officials at the city’s Point Loma sewage treatment plant said their tests indicate that the pollution was limited to Enchanted Cove, the site of Wednesday’s spill.

“The evidence I’ve seen so far is encouraging because it shows the contamination did not spread beyond the cove,” said Alan Langworthy, assistant director of the Metro Waste Water Division.

Test results of water samples collected Thursday show that disease-causing coliform bacteria exceeded the level considered safe in only one area of the cove, according to Susan Hamilton, supervising biologist at the Point Loma plant.

A reading of 1,600 coliform bacteria per 100 milliliters of water was measured at that spot, directly opposite the point where the sludge entered the bay. Water is considered unsafe for bathing if the coliform reading is above 1,000 parts per 100 milliliters sampled. Elsewhere in the bay, the readings were well below that level.

Although the city’s tests indicate that the area of contamination was limited, Melbourn said he will not lift the quarantine nor reduce the area closed to water sports until tests conducted by county health authorities show that the bay is safe.

Melbourn said the county’s test differs from the city’s and takes longer to produce results.

“We’re partial to our test,” he said. “We won’t have a series of reliable readings until Monday. “Then, we’ll evaluate the quarantine and either lift it, reduce the area (off limits) or possibly expand it.”

Exposure to sludge can cause health problems ranging from gastrointestinal disorders to infectious hepatitis. The risk of contracting such diseases is minimal unless the contaminated water is ingested.

The spill occurred at 6 a.m. Wednesday when an earthen berm surrounding one of the ponds used to dry treated sewage sludge on the island gave way. About 1.3 million gallons of sludge, the highly concentrated byproduct of sewage treated at Point Loma, flowed through a 6-foot opening in the berm into a secondary containment area.

About 2,000 gallons then seeped through a crack in the containment area wall and into a storm drain, which carried it to the bay. City officials say the leak in the berm apparently was caused by the earthquake that shook the county earlier this week.

The Regional Water Quality Control Board is investigating the spill. The city could face fines of up to $10 a gallon.