Initial DNA testing of bacteria in the mud and the surf zone at Goleta Beach County Park, where the county is dumping mud from the Jan. 9 debris flow in Montecito, show very low to no evidence of human fecal material, a UCSB scientist said Friday.
“This is good news,” said Patricia Holden, a professor of environmental microbiology who began the DNA study at the beach on Jan. 18. “I’m so delighted.”
Holden said the initial DNA results, covering seven days through Jan. 26, are similar to what her team has detected during water-quality testing at Goleta Beach in the summer months, when no dumping was taking place.
Holden said her team also found very low to no evidence of two pathogens in the mud or the surf zone during initial DNA testing at the beach last month. Those are tests for a human-specific virus and a bacterial pathogen not specific to humans, she said.
The debris from the Montecito cleanup is being trucked first to the Ventura County Fairgrounds, where it is sorted into piles of mud, rocks, wood and metal. From there, the mud is being trucked to Goleta Beach.
In addition, since the storm, the county has been dredging out mud clogging the Salt Marsh Reserve and dumping it at Carpinteria Beach.
Twice-weekly samples taken by county Environmental Health Services from the surf zone at both locations have shown high levels of fecal bacteria since the dumping began. But those tests do not identify whether the bacteria come from humans as opposed to, say, horses, dogs or birds.
Human material is most likely to cause a public health risk.
The high bacterial levels at Goleta Beach are “definitely associated with the mud,” Holden said, adding, “We may not ever know the exact source.”
The county’s emergency permit for the dumping operations at Goleta and Carpinteria beaches will expire on Feb. 20. Holden said she will continue bacterial DNA testing at Goleta Beach through Feb. 28, provided funding is available.
Melinda Burns is a freelance journalist based in Santa Barbara.