What are we swimming in? Experts weigh-in on beach water advisories
After 14 years of holding the La Jolla Cove 10-Mile Relay Swim at the Village enclave, organizers decided to relocate the 15th edition on Sunday, Sept. 25 to La Jolla Shores. The reason behind the move was the high levels of Fecal Indicator Bacteria (FIB) found at The Cove, which prompted a Bacteria Exceedance Advisory from the San Diego County Department of Environmental Health. According to the website sdbeachinfo.com the advisory was posted on Sept. 1 and still stands.
Swim event director John Heffner explained, “We got an indication that the lifeguards were banned from going in the water as long as the bacteria signs were up, and we couldn’t operate our event without the lifeguards being in the water.”
In fact, the San Diego Lifeguard Services policy states that no recreational contact with the water is allowed if the County has issued a high bacteria or a general advisory, routinely released after it rains. Lifeguard Lt. Rich Stropky confirmed the information. “That means we don’t go in the water unless we need to for work-related stuff — so no workouts, no paddle boards, no swimming in the area.”
La Jolla Cove Swim Club President Dan Simonelli, who is also involved in organizing the 10-Mile Relay Swim, said directors didn’t want to risk participants’ health. He said he stopped swimming at The Cove in September. “I went to The Cove and it stunk so bad you could taste it in the water. I just finally said, I’ve heard of friends and other swimmers that have gotten sick, and I can’t risk it getting some infection any longer,” he said.
How water quality is measured
San Diego County issues two kinds of Bacteria Exceedance Advisories, one for acute situations (when the statewide thresholds are exceeded on a given day, which means one-time exposures may cause illness) and another for chronic risks (when the average for a 30-day period is exceeded, which means multiple-day exposures may cause illness). Keith Kezer, program coordinator of the Land and Water Quality division of the County’s Environmental Health Department, told La Jolla Light the current bacteria advisory at The Cove belongs to the second kind.
To calculate chronic risks, the County uses the “geometric mean” — a way to determine the average among a set of values — of five measurements within a 30-day period. When the thresholds for the geometric mean are exceeded, as Kezer puts it, “If someone goes in (the water) multiple days, because they are having more exposure, the risk of them getting sick is greater.” Therefore, the thresholds for a chronic bacterial advisory are lower.
Another example of a chronic advisory for bacteria exceedance is Children’s Pool (aka Casa Beach). “We have enough data that we know this risk is maybe not always there, but it’s predominantly there,” Kezer explained.
The Environmental Health Department conducts periodic water tests on every beach along the County’s 55-mile coastline. Daniel Collins is the environmental health technician who performs the task. The Light accompanied Collins on a sampling trip to La Jolla Shores last week. “If you see me here tomorrow, the water was bad today,” he said, referring to the policy of next-day testing carried out when a sample comes back exceeding the standards.
He explained that a good water sample is taken 12-20 inches below the surface and well above the ocean’s floor to avoid any contamination that might not be representative of the overall water quality. His equipment consists of a 6-foot pole that extends to 12 feet if the surf is high, and a 100-milliliter bottle provided by the laboratory that contains the water.
Immediately after the sample is taken, it’s put in a cooler with ice to preserve the bacteria from growing. Once Collins collects all the samples for the day, he drops them off at the laboratory where they are analyzed with culture methods. “Essentially, you take one bacteria, which is hard to detect, give it food and let it grow into a colony, and then you can count it,” Kezer explained. This process takes 24 hours, which is one of the challenges of this method.
The morning after, at 16 hours of cultivation, the County obtains a preliminary report on the bacteria and if the thresholds have already been exceeded, it issues a Bacteria Exceedance Advisory. This is almost one whole day after the samples are taken.
How accurate are measurements?
Heal the Bay is an environmental nonprofit organization dedicated to making the coastal waters and watersheds of the Greater Los Angeles safe, healthy and clean. Beach water quality modeler Ryan Searcy, who created models that predict water quality, criticized the current measuring method.
“You typically won’t receive the results back until the following day, and during that time conditions can change, water quality can increase. The result you receive is accurate by the time it was taken,” he said. “Until we have a method that can almost instantaneously get us bacteria information we never really know what the concentration of bacteria is.”
Searcy is working on a series of predictive models that can fill in the gaps between water quality samples. “We take old samples and environmental data like rain, temperature, waves and water conditions we can easily measure and we predict, based on statistics, if the water will be clean or dirty. The benefit of this program is there’s water quality information every single day rather than once a week,” he explained.
Assembly Bill 411 of the Health & Safety Code of California mandates local authorities across the State test for total coliform, fecal coliform and enterococci bacteria (aka FIB) on a weekly basis, and take the appropriate measures if the standards are exceeded. But many may be surprised to learn none of those bacteria can actually make humans sick.
Does fecal-indicator bacteria cause illness?
“Those three bacteria groups have been found through studies to be present where there are other pathogens that do make people sick,” Kezer explained. Some of the illnesses related to these bacteria include skin rashes and Gastrointestinal Infection (GI).
UC Los Angeles Associate Vice Chancellor for Environment & Sustainability, Dr. Mark Gold, said he believes there is a sufficient correlation between the FIB and the pathogens that make humans sick. “Surprisingly so, this has been one of the big areas of debate and research for the last 25 years, and the reason why is that most FIB are not the pathogens that get you sick when swimming, but they are an indicator of health risk,” he said. “Results of studies all over the world say that high densities of enterococcus bacteria is associated with health risk for GI, even though the association might be different depending on the source of the enterococcus.”
However, not everyone in this field agrees with this theory. Ruth Kolb, program manager in the City of San Diego Stormwater Department, doubts the effectiveness of measuring the FIB in Southern California beach waters. “Over the last 30-35 years, all the epidemiology studies that show the correlation between bacteria and human illness have been done in the East Coast and the Midwest where there’s a lot more contamination in the receiving water. In Southern California, we don’t have those combined systems of stormwater and sewer, so (studies) are showing that our water quality is very good and the Environmental Protection Agency (EPA) studies are geared toward areas where FIB can do a better job at predicting illness.”
Research shows that the correlation between FIB and human pathogens is lower when the source of the contamination is non-human, for example at La Jolla Cove, where the source of the bacteria is presumably animal, more specifically sea lion waste. (FIB is present in the feces of all warm-blooded animal species).
“The health risk is generally considered to be less with non-human contamination than when you have human sewage in the water,” said Dr. Gold, “but there are many cases of cross-contamination illness between species, so there’s still a risk.”
Studies have been done for cross-contamination with birds, cows, horses or pigs, and while the amount of risk varies, a lot of those sources, risk-wise, are far lower than from human pathogens. Dr. Gold said, “There hasn’t been a specific study on people who swim on marine contaminated water with pinnipeds. That study has never been done because the number of beaches that are like La Jolla Cove you can count with only one finger.”
Kezer added, “Just like with anything, there’s advantages and disadvantages to (measuring FIB). There’s going to be some areas where it works, and others where it doesn’t work.”
A new approach
A different approach is being developed by the Southern California Coastal Water Research Project (SCCWRP). The “rapid method” gives results within four hours and searches for the human marker HF183, tracking bacteria that actually lives in humans. City stormwater expert Kolb said, “EPA and the State Water Board have been funding the SCCWRP to help develop methods that will be faster and more accurate by trying to develop something that works in four hours, and developing measures that are more accurate at tracking the pathogens.” Public Information Officer Anthony Santacroce said the City is also funding the development of this project.
For now, this new method is considered expensive and ineffective by the authorities, who still mandate that FIB are tracked on California beaches. However, Dr. Gold, who is also associated with Heal the Bay efforts to develop a predictive model for beach water quality, believes that until water testing becomes a daily venture, beach water quality will still be a question mark in Southern California.
“The beauty of the rapid method is that is going to give you a better idea, but you’ll need to start doing daily monitoring. Ideally, we’d have rapid methods and every beach would be monitored daily, but that’s not the case, the monitoring agencies aren’t willing to spend that kind of money.”
COMING NEXT WEEK: “What are we surfing in?” a report on stormwater infrastructure in La Jolla.