Blue-green algae threaten local lakes

You have arrived at your favorite summer lake, armed with family, pets, fishing gear, boat, and more, only to find a nasty, green scum along the surface of the lake. Blue-green algae have invaded your favorite water. Unfortunately, blue-green algae blooms are showing up more often in Southwest Washington’s lakes. It has long been a problem for certain bodies of water, but a warming climate is causing it to happen more often, and in more waters. Algae blooms are a result of nutrients in the water, and warm water temperatures, according to Shawn Ultican, an aquatic pesticide permit specialist for the Department of Ecology in Washington. He said not all algae are toxic, but there is no way to know whether it is or not without testing the water. “If they see scum floating on the water or collecting on the shoreline, that may mean higher risk, but that doesn’t tell you for sure that toxins are present,” Ultican said. “You can’t tell by looking at the water whether the algae bloom is producing toxins, so it requires laboratory testing to know for sure.” The testing can tell if there are cyanobacteria present, which is an organism that are typically behind the toxic blooms. They don’t always produce toxins, but they are the ones that are most likely to cause it. Some algae can be beneficial, and provide nutrition for the bottom of the food chain, but blue-green algae may carry a threat. There are several different toxins that can be produced, and they can be present in very low levels, or high levels. The state of Washington has established recreational guidelines, and when toxins get above a certain level, that’s when they issue an advisory. That notice usually comes from the local county health jurisdiction because they have the authority to post a health advisory. If you observe signs of algae, it may or may not be safe to fish or swim. Since there is no way to tell until the water is tested, if in doubt, stay out. Sometimes there may be no signs of a bloom, but the toxins may still be there. Ultican said that at times the bacteria are present in water that looks clear. This can result after algae die, and release toxins into the water. The nutrients that feed these blooms are often a result of runoff from fertilizers used in agriculture, or suburban lawns. These nutrients get flushed into the lakes via storm drains, sewer systems, and creeks. Waterfowl can also be a driving force. If a lake gets a lot of waterfowl their feces can fuel a bloom. Another source may be failing septic systems. Blooms can also be produced by applications of herbicides to control invasive plants. When these plants die, they release nutrients into the water that can trigger a bloom. Warm, sunlit water can then fire up the blooms, which feed on those nutrients. There are risks to humans that come in contact with the water. They can develop a rash, or if they swallow the water, it can sicken them. Children are more vulnerable because they often swallow water while swimming. “Another risk is to pets, especially dogs,” Ultican said. “They may get into the water and drink it and consume the algae that way, or they get the scum on their fur and then lick it.” Dogs can get extremely sick, and even die from these toxins. Cyanobacteria can produce nerve toxins (neurotoxins) as well as liver toxins (hepatotoxins). If you suspect you or a pet has been sickened by cyanobacteria, call your doctor or veterinarian right away. Signs of illness can include the following: Neurotoxin (nerve) poisoning — In people, signs include numbness of the lips, tingling in fingers and toes, and dizziness. In animals, signs include weakness, staggering, difficulty breathing, convulsions, and death. Signs appear within 15-20 minutes after ingestion. Hepatotoxin (liver) poisoning — Signs include abdominal pain, diarrhea, and vomiting in humans and death in animals. It may be hours or days before signs of liver poisoning appear. The warming climate means the conditions for blooms are increasing. In April, a drought declaration was issued for all watersheds in Washington due to the low snowpack, plus multiple years of lower than usual precipitation. With less snow melt, recreationists should expect rivers and lakes to be shallower, leading to warmer water, and lower dissolved oxygen. This can make water bodies vulnerable to harmful algal blooms. Some local lakes tend to bloom every year. Vancouver Lake is well known for heavy algal blooms, fueled by the shallow lake’s high nutrient level. Others known for the toxic algae include Lacamas Lake near Camas, and Rowland Lake in the Columbia River Gorge. In the past, there have been warnings issued for both Lacamas and Rowland lakes. It is a good idea to check the Department of Ecology website to see if there is a warning issued for the lake you wish to visit. Those postings can be found here: https://www.nwtoxicalgae.org/ If a lake is found to have high levels of toxins, local county health departments will post warning signs at the affected area. They may also completely close a lake or beach if the levels are high enough. Clark County advisories are posted at https://clark.wa.gov/public-health/public-beaches If you see signs of algal blooms in any local lake or body of water, you can report it for testing to https://clark.wa.gov/public-health/report-health-concern. You can also help by taking samples of the water and submitting it for testing. The Washington State Toxic Algae website also offers lots of information, including an interactive map of infected sites, how to spot a bloom, how to report a bloom, and examples of signing for impacted waters. The Washington Department of Health also offers a lot of information about algae in local lakes. Access that information at https://doh.wa.gov/community-and-environment/contaminants/cyanobacteria Remember, the best way to avoid sickening yourself, your children, or your pets, is to avoid any water that appears to have a bloom.

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Warm water temps result in blooms that can be toxic

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