The Department of Health and Human Services is notifying recreational
users of the South Fork Eel River and other fresh water bodies to take
precautions to avoid contact with blue green algae. In 2002 three dog
deaths occurred after the animals swam in areas of stagnant water with
significant growth of blue green algae. At least two of these deaths were
most likely caused by the ingestion of blue green algal toxins. There have
been no reports of illness or other effects involving humans.
The Mendocino County Environmental Health Division, and California Animal
Health and Food Safety Lab found blue green algae and their associated
toxins in South Fork Eel River water samples, and in the stomach contents
of the dead animals. No other toxins were found that could have caused the
deaths.
Blue green algae “blooms” or large build-ups of algae can be triggered by
low river flows and high nutrient levels in the summer and fall. When
algae cells die or are damaged, toxins may be released at levels dangerous
to pets and livestock if they drink the water or eat the algae. (Dogs may
ingest algae when licking their fur after swimming.) Human impacts are
infrequent because people usually avoid ingesting algae or swimming in
areas of algae blooms. However, swimmers or boaters elsewhere have
experienced skin irritation, gastrointestinal disorders and allergic
respiratory reactions from blue green algae contact.
The Department of Health and Human Services recommends the following
guidelines for recreational users of all freshwater areas:
1. Do not allow pets to swim in or drink river water that is heavily
infested with algae.
2. Limit your contact with water where algae blooms are visible,
particularly dense mats of algae. Do not wade or swim in this water.
Closely supervise young children, as they are more at risk due to their
small body size.
3. Do not drink, eat or handle the algae and avoid ingesting the river
water.
4. Swimmers should shower and pets be rinsed with tap water immediately
after bathing.
5. Use water-resistant gloves to remove unwanted algae from shorelines.
6. Ranchers should not allow livestock to drink water from contaminated
rivers or streams.
Although there have been no reports of human illness in Humboldt County,
people could be affected by the toxins. Pets and other animals that swim
in or drink river water are most likely to be affected by blue green algae
toxins. However, following the above precautions to avoid direct contact
with algae should prevent an illness or any adverse reaction.
The Department does not expect domestic water supplies to be affected
unless the water intake is submerged in heavy blue green algae
concentrations. Owners of private water systems should check for algae
near water intakes. Algae will cause odor and taste problems in drinking
water. All water systems using surface water for domestic use should be
first filtered to remove algae cells and then disinfected by a method
other than boiling. Disinfection without first filtering the water will
kill the blue green algae, causing it to release its toxins into the
drinking water.
Please contact the Department of Health and Human Services, Division of
Environmental Health, at (707) 445-6215 or 1-800-963-9241 for further
information. In Mendocino County, please contact the Mendocino County
Health Division of Environmental Health at (707) 463-4466. Fact sheets
including information for veterinary workers are available at either
county office. For further information concerning animal health, please
contact the State Animal Health Branch at (707) 826-1658.