Just in case the refilling of SLO’s Laguna Lake had residents or visitors hankering for a dip; stay out of the water.
In an announcement that almost “flew under the radar” following a Friday evening news release, City of SLO officials said that a toxin produced by blue green algae has been detected in the lake.
Central Coast Regional Water Quality Control Board staff took samples and found microcystin. Harmful to humans, pets and wildlife, the toxin builds up in ecosystems after exactly the kind of warm weather and drought conditions the Central Coast has experienced.
The announcement states that two samples were collected from the lake: one from the edge of the lake near the Madonna Road bridge and one at the boat launch area in the park. Lab staff reported microcystin at 5.4 milligrams per liter (ug/L) for the sample at the boat launch and 9.2 ug/L for the sample near Madonna Road. The State’s guidance recommends posting a warning level sign when concentrations of microcystins exceed 6.0 ug/L. This level is based on the 2012 Office of Environmental Health Hazard Assessment’s (OEHHA) suggested action levels for human health protection. Although the sample from the boat launch did not exceed that level, the sample from the Madonna Road overflow area did. Following the State’s guidance recommendations, these levels warrant posting the State-issued warning level signs around the lake.
In fact the surface water near the Madonna Road bridge was obviously discolored over the weekend.
Bob Hill, the City’s Natural Resources Manager wanted to reassure residents that the lake does not connect to the municipal drinking water system and does not pose a danger, except through direct contact.
All three of the City’s surface water drinking supplies (Nacimiento, Salinas, and The City’s announcement added that: Whale Rock) are routinely monitored by the San Luis Obispo County Water Quality Laboratory for microscystin, as well as a broad range of other potentially harmful substances such as metals, fecal coliform, and other bacteria.
Water bodies throughout the State are experiencing microcystin levels produced by blue green algae that exceed state levels due to hot summer weather combined with drought conditions. Consistent with the State’s guidance, the City is following the recommendation to post warning signs at the lake where pets or people may have contact with the water.
– Photo by Camas Frank
