Toxic algae blooms are on the rise in the Columbia River, prompting increased concern for public health and wildlife. The Benton-Franklin Health District (BFHD) has reported the presence of toxins below recreational thresholds at popular locations such as Leslie Groves Swim Beach and Howard Amon Park. While water treatment facilities have not detected contamination, the BFHD is urging heightened caution, especially for pet owners, as animals are particularly susceptible to harmful algal blooms (HABs).
The peak season for these blooms typically lasts until early October. Factors contributing to their proliferation include elevated water temperatures and reduced river levels, conditions often exacerbated by climate change. Warmer water temperatures accelerate the growth of cyanobacteria and promote water stratification, further supporting bloom development. Nutrient pollution from agricultural runoff and wastewater also significantly contributes by providing essential elements for rapid algae growth. Cyanobacteria can produce potent toxins like anatoxin-a, which can affect the nervous system and be fatal in severe cases. Health officials advise avoiding contact with discolored or scummy water, emphasizing the "when in doubt, stay out" principle. Tragically, several dog deaths have been linked to toxic algae exposure along the Columbia River in recent years. The U.S. Environmental Protection Agency (EPA) is actively researching methods to sample and track these toxins, with initial efforts focused on the Columbia River. The river's flow dynamics, influenced by hydroelectric dams, can slow water movement and increase temperatures, creating ideal conditions for blooms. Addressing this issue requires a multifaceted approach, including reducing nutrient pollution and adapting to climate change impacts.
The U.S. Army Corps of Engineers and the U.S. Geological Survey are also conducting studies on the Columbia River's toxic algae. The Army Corps has been sampling bi-weekly to study cyanobacteria and cyanotoxins, determining that the toxic algae is benthic, or bottom-dwelling, and regularly producing anatoxin-a in quantities exceeding state guidelines. The BFHD continues to monitor recreational sites, with their next sampling date scheduled for August 11th. While no significant levels of toxins were detected at recreational sites this week, an increase in floating algal mats, which can pose a risk to children and dogs if ingested, was observed.