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Tracking IB's 'smelly water'

Originally published July 27, 2010 at 10 p.m., updated July 28, 2010 at 12:02 a.m.
For the past decade, surfers and others have complained about an unusual odor wafting over the sand and waves of Imperial Beach.
It’s often described as having a detergentlike quality, and it comes with shimmery bubbles in the surf zone. One scientific paper calls it “smelly water.”
For just as long, the on-again-off-again scent has defied attempts to determine its source and answer questions about whether it poses dangers for beach users.
“We are really concerned because our noses and all of our physical senses when we are in the water are telling us one thing, and the tests are telling us another,” said Ben McCue, a surfer and coastal program manager for the nonprofit group Wildcoast in Imperial Beach.
In recent weeks, conservationists have fashioned a plan to solve the mystery using high-end tests that go beyond the typical sampling for indicator bacteria in coastal waters. They said the issue is resurfacing now because upgrades at the International Wastewater Treatment Plant in San Ysidro are nearly done after years of debate, allowing beach advocates to focus on other issues in one of the county’s most polluted areas.
“We are going to nail it down this summer,” McCue said.
As usual, the main barrier is money — an estimated $15,000 to look for chemical clues that can help pinpoint the source of the odor, which is widely thought to be from wastewater. It will take more time and money to determine whether the impurities cause human health problems.
The San Diego Regional Water Quality Control Board, which regulates water pollution in the area, offered about $14,000 for testing several weeks ago. Those funds were only available until the fiscal year ended June 30. No reports of odor problems surfaced during the testing window, so the plan was shelved.
Regional board officials said they are trying to free up money from fines paid by polluters to underwrite the analysis. Until that happens, they are unsure about how to view the occasional stink.
“That is one of the reasons I am interested in exploring this further — to find out what we don’t know,” said David Gibson, head of the regional board. “It’s worthwhile investigating.”
A natural suspect is the Tijuana River, which for decades has carried sewage-tainted runoff from Mexico to South Bay beaches during the rainy season.
What worries McCue is that the unsettling smell occurs in the summer when the river isn’t flowing to the Pacific Ocean.
Instead, beach users have noticed the odors when nearshore currents are moving north. Some have also linked it to southwest winds.
One leading theory is that the smell is from the South Bay Ocean Outfall, which deposits treated sewage from the United States and Mexico about 3.5 miles offshore near Imperial Beach.
McCue and others said it’s more likely that the smell is from treated and untreated sewage dumped into the surf zone roughly five miles south of the U.S.-Mexico border at Punta Bandera.
The plume from Punta Bandera typically travels south but it moves north across the border about 12 percent of the time, according to a 2009 paper by Eric Terrill, director of the Coastal Observing Research and Development Center at Scripps Institution of Oceanography.
His research wasn’t designed to pin down the funky odor.
“Right now, I don’t think we have a gold-standard test that has said unequivocally that it is Punta Bandera,” Terrill said. “Wildcoast is on the right track. … A special study needs to be done.”
One reason the odor mystery remains unsolved is that standard beach water tests assess fecal indicator bacteria, which can be killed by treatment or diluted to the point that they are not found.
The problem is that there still could be harmful viruses or other pollutants in “smelly water” even if the bacteria aren’t detected.
Clay Clifton, watershed monitoring program manager for San Diego Coastkeeper, said he started hearing about the strange smells shortly after he started working at the county’s Department of Environmental Health in the late 1990s.
“We said, ‘Let’s document that there is a contamination event happening,’ ” Clifton said. “This happened year after year where we went out with our traditional bacterial analysis, collected samples and processed them. … We never had any exceedances (of water-quality standards).
“We were scratching our heads and wondering what is going on,” Clifton said.
Any new sampling efforts likely will target ingredients in laundry soap. Some detergents used in Mexico aren’t approved in the United States, making them useful indicators of where wastewater originates.
In addition, tests may look at caffeine or artificial sweeteners, traces of which could connect the odors to human excrement and raise concerns about the potential for waterborne illnesses. That kind of chemical fingerprinting is several times more expensive than fecal indicator tests.
“Usually when you test the water, you know what you are looking for,” McCue said. “In this case, we are trying to figure out what’s in the water. It’s almost a reverse investigation.”
Even if the regional board agrees to finance a study, success will hinge on the smell lingering long enough to get several water samples.
“These events come and go depending on what the surf is doing,” Clifton said. “You could very easily miss it.”