Sections of Bolinas Beach have reopened following a three-month closure because of contaminants.
The county discovered the pollution in the Mesa area in September, when inspectors visited a site for a permit application. They saw potential effluent coming out of a cliff above the beach and discolored, odorous and crystallized liquid in soil surrounding the bluffs.
“In some areas the water was seeping and in others it was flowing,” Sarah Jones, director of the Marin County Community Development Agency, said in September.
Tests revealed that the soil contained ammonia, E. coli and coliform bacteria, raising concerns about the possibility of sewage leaking from private septic systems.
The San Francisco Bay Regional Water Quality Control Board conducted more tests last month and did not find the same results.
“We thought that it could have potentially been human waste,” Marin County Executive Derek Johnson said. “However, we did a bunch of tests and we determined that there was no evidence of sewage from septic systems or human waste.”
The Bolinas Community Public Utility District confirmed that its tap water was safe to drink. The water is sourced from outside the Mesa area, district staff told county officials.
Johnson said the liquid coming out of the bluffs could have come from a creek or agricultural operations.
“We just don’t know, and so we need to advise folks and say, if you’re on the beach, just be out there with caution,” he said.
Bolinas is a popular surfing destination.
“Surfers for the most part know that when you get done, particularly after heavy rainfalls where there is a fair amount of runoff, to take a shower,” Johnson said.
The county plans to issue safety advisories, including signs that warn visitors about soil near the bluffs that could be contaminated as well as potential rockfalls and slides from the bluffs. Visitors are also advised to avoid direct contact with the water and sand adjacent to the bluffs.
“With new data in hand, we can cautiously restore access to this cherished part of our coastline,” said Dr. Lisa Santora, the Marin County public health officer. “However, work remains in identifying factors contributing to the seepage, and there are many lessons learned about how the county had better respond to issues like this in the future.”
County officials also announced this month they will work with the Bolinas Community Public Utility District to seek wastewater treatment improvements.
