NORTHERN CALIFORNIA – Due to its potential health risks, federal, state and county agencies are urging swimmers, boaters and recreational users to avoid direct contact with or use of waters containing blue-green algae (cyanobacteria), now blooming in a reach of the Pit River arm of Shasta Lake, and in Lake Britton in Northern California.

Sampling has confirmed low concentrations of cyanobacteria (Anabaena spp.) and the associated toxin, Anatoxin-a, in the upper Pit River arm of Shasta Lake, in the Pit River at Big Bend, and near the State Park Boat Ramp at Lake Britton.

Recreational water users of the Pit River arm of Shasta Lake, and Lake Britton are urged to use caution and avoid getting in the water or letting dogs swim near these bloom areas.

Blue-green algae can pose health risks, particularly to children and pets. The affected area is approximately between the “No Ski” buoy markers near the middle arm and the buoys at the head of the Pit arm and in Lake Britton.

The bloom density is variable and wind and currents can move and concentrate the bloom. It is recommended that people and their pets avoid contact with water in locations with blooms, and avoid swallowing or inhaling water spray in an algal bloom area.

Although a bloom was not observed at Big Bend, Anatoxin-a levels in the water indicate the same cautionary measures are recommended along the lower Pit River between Lake Britton and Lake Shasta.

The algal bloom appears as bright green in the water with streaks that look like spilled paint. The blooms can also appear as blue-green, white or brown foam, scum or mats that can float on the water and accumulate along the shore.

Recreational exposure to toxic blue-green algae can cause eye irritation, allergic skin rash, mouth ulcers, vomiting, diarrhea, and cold and flu-like symptoms. Liver failure, nerve damage and death have occurred in rare situations where large amounts of contaminated water were directly ingested.

Pets can be especially susceptible since they tend to drink the water and lick their fur after going in the water.

The Statewide Guidance on Cyanobacteria and Harmful Algal Blooms recommends the following for blue-green algae impacted waters:

– Take care that pets and livestock do not drink the water, swim through algae, scums or mats, or lick their fur after going in the water. Rinse pets in clean water to remove algae from fur.
– Avoid wading, swimming, or jet or water skiing in water containing algae blooms or scums or mats.
– Do not drink, cook or wash dishes with untreated surface water from these areas under any circumstances; common water purification techniques (e.g., camping filters, tablets and boiling) do not remove toxins.
– People should not eat mussels or other bivalves collected from these areas. Limit or avoid eating fish from these areas; if fish are consumed, remove guts and liver, and rinse filets in clean drinking water.
– Get medical treatment immediately if you think that you, your pet, or livestock might have been poisoned by blue-green algae toxins. Be sure to alert the medical professional to the possible contact with blue-green algae.

For more information visit the following:

– California Department of Public Health: http://www.cdph.ca.gov/healthinfo/environhealth/water/Pages/Bluegreenalgae.aspx ;

– State Water Resources Control Board - California CyanoHAB Network: http://www.mywaterquality.ca.gov/monitoring_council/cyanohab_network/index.html ;

– California Office of Environmental Health Hazard Assessment, information on microcystin: http://oehha.ca.gov/ecotoxicology/general-info/information-microcystins ;

– US Environmental Protection Agency CyanoHAB Web site: https://www.epa.gov/nutrient-policy-data/cyanohabs ;

– US Environmental Protection Agency, Anatoxin-a report: https://www.epa.gov/sites/production/files/2015-06/documents/anatoxin-a-report-2015.pdf .