Officials with the Humboldt County Department of Health and Human Services (DHHS) are warning recreational users of the South Fork Eel, Van Duzen, Klamath and Mattole rivers, Big Lagoon, Freshwater Lagoon and all other freshwater bodies to avoid contact with algae this summer.
Low flows along the South Fork of the Eel River as well as the Van Duzen, coupled with sustained high temperatures in the inland areas, have created the ideal conditions for rapid blooming of blue-green algae.
DHHS is aware of 11 dog deaths that may have been caused by blue-green algae poisoning since 2001. The dogs died shortly after swimming in Big Lagoon, the South Fork Eel River and the Van Duzen River.
A nerve toxin associated with blue-green algae was found in the stomachs of the dogs that died on the South Fork Eel River in 2002. The same toxin was found in water samples from the South Fork Eel and Van Duzen rivers in 2009 just after two dogs died. This poison is the most likely cause of the dog deaths on these rivers. Dogs are more vulnerable than people because they may swallow the toxin when they lick their fur. The onset of symptoms can be rapid; dogs have died within 30 minutes to one hour after leaving the water.
Blue-green algae blooms that produce a liver toxin have been documented in Klamath River reservoirs and the Klamath River this year. The current status of this river may be found at the Klamath Basin Monitoring Program website: http://www.kbmp.net/blue-green-algae-tracker.
Blue-green algae can be present in any freshwater body. It looks like green, blue-green, white or brown scum, foam or mats floating on the water. Usually, it does not affect animals or people. However, warm water and abundant nutrients can cause blue-green algae to grow more rapidly than usual. These floating algal masses, or “blooms,” can produce natural toxins that are very potent. Dogs and children are most likely to be affected because of their smaller body size and tendency to stay in the water for longer periods.
Potential symptoms in dogs following exposure to blue-green algae toxins can include lethargy, difficulty breathing, salivation, excessive urination, vomiting, diarrhea or convulsions. People can experience eye irritation, skin rash, mouth ulcers, vomiting, diarrhea and cold- or flu-like symptoms.
DHHS officials recommend the following guidelines for recreational users of all freshwater areas in Humboldt County:
o Keep children, pets and livestock from swimming in or drinking water containing algal scums or mats.
o Adults should also avoid wading and swimming in water containing algal blooms. Try not to swallow or inhale water spray in an algal bloom area.
o If no algal scums or mats are visible, you should still carefully watch young children and warn them not to swallow any water.
o Fish should be consumed only after removing the guts and liver and rinsing fillets in tap water.
o Never drink, cook with or wash dishes with water from rivers, streams or lakes.
o Get medical attention immediately if you think that you, your pet or livestock might have been poisoned by blue-green algae toxins. Be sure to tell the doctor about possible contact with blue-green algae.
Human activities can have a big effect on nutrient and water flows in rivers, streams or lakes. Phosphorous and nitrogen found in fertilizers, animal waste and human waste can stimulate blooms. Excessive water diversions can increase water temperatures and reduce flows. People can take the following measures to prevent algal blooms in local waters:
o Be very conservative with the use of water, fertilizers and pesticides on your lawn, garden or agricultural operation.
o Recycle any “spent” soil that has been used for intensive growing by tilling it back into gardens, or protect it from rainfall to avoid nutrient runoff.
o Plant or maintain native plants around banks. These plants help filter water and don't require fertilizers.
o Pump and maintain your septic system every three to four years.
o Prevent surface water runoff from agricultural and livestock areas.
o Prevent erosion around construction and logging operations.
For more information, contact the DHHS Division of Environmental Health at 707-445-6215 or 1-800-963-9241. People may report unusual blooms or conditions, including photographs, to Environmental Health by emailing firstname.lastname@example.org. The California Department of Public Health website also has more details at www.cdph.ca.gov/healthinfo/environhealth/water/Pages/bluegreenalgae.asp.