Why is human DNA seeping into the sea near a Southern California pier?

On any given day, surfers are paddling out near the San Clemente Pier to catch waves, a popular seaside destination that also draws locals and tourists who splash around in the saltwater.

But in those waters is something that’s not supposed to be there: human DNA, aka human waste. City officials are trying to solve the mystery of where it is coming from so they can prevent the contaminants from ever hitting the sea.

Officials have been grappling with pier pollution for years – it’s been on the city’s radar big time since 2015 and made headlines when San Clemente appeared on Heal the Bay’s Beach Bummer list in 2017 and for several years following.

In 2019, the city contracted with Wood Environment and Infrastructure Solutions to do a “Pier Bacteria Source Characterization Study” and formed a task force to spearhead figuring out why its ocean water was so dirty.

When testing came back showing avian DNA present around the pier, the city put up netting to control roosting under the pier. That seemed to get the problem somewhat under control.

The city earned a “C” in the Heal the Bay report earlier this year, an improvement but indicating an issue still existed.

With testing also showing human DNA, City Council members agreed Tuesday, Sept. 8, to extend the consultant contract to continue looking at how human waste is getting into the water.

“I didn’t know that,” said surfer Jeff Lukasik, who frequents the pier often. “Hopefully they get it under control. That’s super gross.”

Samples done early this year are still detecting human DNA in the water from two storm drains that pipe discharge to the ocean shoreline under the pier, a report by staff to the City Council said, and “additional time is needed to continue the study to again attempt to locate and abate the human source in the watershed.” The report didn’t say how much more that would cost.

The city has already taken several steps to find the source of the contaminants.

Sewer and storm drain lines were surveyed with video cameras to identify any infrastructure problems that could be the source of human DNA. So far, there’s been no city-owned infrastructure issues identified, officials said.

Then, the city checked with street sweepers to see what kind of water they used. Turns out, they use potable water and not recycled water, which can emit a human-genetic marker although it is dead, city staffers said in their report to the council.

What about the water used on the grass near the pier bowl area? That’s also potable water, not recycled.

Local business owners and managers were also interviewed to see if human waste was being left behind in and around trash dumpsters, or by homeless individuals, on their property. But “no businesses noted this issue during the interviews.”

After these investigations and a few more, such as checking waste disposal companies to see if they were leaking onto streets, it was thought the issue was under control … until another sample was taken.

“Unfortunately, human DNA was still detected in the discharge water from the storm drain system,” the staff report said.

So the city is going back to the drawing board in trying to identify the human waste source, including doing more recordings in the sewer and storm drains, seeing if trash haulers are discharging liquid and noting “any homeless people and locations that could possibly contribute human DNA to the storm drain system,” officials said.
“Once these management measures are repeated and staff feel confident the potential sources are abated, the city may need to conduct additional water quality sampling and analysis to confirm if human DNA is present,” the staff report said.

Councilman Gene James, on the pier earlier this week for a welcome ceremony for the upcoming world surf finals, said it’s just one reason the town’s Clean Ocean Fund, which requires voter approval, needs support. Funding for the ongoing testing came from reserves of that fund.

“It’s something that absolutely we have to deal with,” he said. “Where is it coming from?”