Is there toxic algae in the Klamath River system?
David Smith
Siskiyou Daily News
11/04/2010
Klamath River —
Blue-green algal species exist in Upper Klamath Lake, Copco Reservoir and Iron Gate Reservoir, according to Dr. Jacob Kann of Aquatic Ecosystem Sciences and Chauncey Anderson of the United States Geological Survey Oregon Water Science Center, although differing conditions in each area determine which species dominates.
According to Kann, the high phosphorous conditions in Upper Klamath Lake allow dominance by the species Aphanizomenon flos-aquae, which is used as a popular dietary supplement, and according to Anderson has long been considered to be non-toxic.
In the Copco and Iron Gate reservoirs’ nitrogen-rich environments, however, Kann said the species Microcystis aeruginosa dominates, which the Centers for Disease Control (CDC) lists as a producer of cyanotoxins.
According to the CDC, cyanotoxins produced by Microcystis can promote tumors and produce hepatotoxins, which damage the liver.
Kann and Anderson both stated that the Iron Gate and Copco reservoirs contain warm, nutrient rich and calm waters in which the toxin-producing algae can grow.
“Even now there has never been an exposure risk in the Klamath River immediately upstream from Copco, but numerous public health exceedances occur in the reservoirs and downstream, all the way to the estuary,” Kann said. “Such downstream levels are a direct reflection of the algae and toxin leaving Iron Gate Reservoir.”
According to a 2009 report in the journal Toxicon, titled “Recreational exposure to microcystins during algal blooms in two California lakes,” there are “no regulations defining acceptable levels of cyanobacterial toxins in drinking or recreational waters” in the United States.
The report, based on a 2007 study conducted in Siskiyou County during the occurence of cyanobacterial algal blooms (CyanoHABs) containing Microcystis, stated that 81 adults and children were tested during the month of August after recreational exposure to CyanoHABs in the Copco and Iron Gate reservoirs.
Representatives from Siskiyou County, the Karuk Tribe, the CDC and a number of laboratories were involved in the study.
“It is likely that healthy persons will not have adverse acute effects from periodic exposures to [Microcystis] in aerosols generated by water-based recreational activities in lakes with patches of toxin-producing blooms,” the report reads. “However, these healthy persons clearly are exposed to potent hepatotoxins.”
