An algal bloom is becoming increasingly toxic

A healthy five-month-old husky puppy in Utah’s Zion National Park started seizing an hour after playing in the North Fork of the Virgin River on the Fourth of July last year. Keanna was determined to have swallowed toxic algae from a river by local health officials.

Despite the danger of the North Fork, the Park Service warned against all recreation on this popular park for the rest of the summer. This effectively closed one of the park’s most popular attractions. There are dozens of popular places throughout the U.S. where toxic algae thrive in hot weather. Zion is just one of them. Rivers and reservoirs across Utah have experienced unprecedented algal growth once again (the North Fork of the Virgin River is still under an advisory), while algal blooms continue to close bodies of water from Washington to Florida (a total of 278 were closed in 2020). The cause of the respiratory death of a family near Yosemite may have been algae.

According to a report published by the nonprofit Environmental Working Group, toxic algae outbreaks occurred in every state except Alaska from May to October 2020. Since the group started keeping track in 2010, more than 400 cases have been reported. Reports of blooms have increased by 46 percent since last July, according to the organization.

Why do you call blue-green algae toxic? Cyanobacteria are microscopic cyanobacteria that occur naturally. Nutrients, such as phosphorus and nitrogen, cause bacteria to multiply out of control when water warms up, leading to algal blooms. When that happens, things can really get complicated.

There are thousands of different types of toxins that the bacteria can produce when they bloom, including saxitoxin, which causes paralysis, and microcystin, a liver toxin and carcinogen. Rashes, diarrhea, sore throats, and cardiac arrhythmia can be some of the reactions humans may experience. There is still some digging to do into the long-term effects – a number of diseases like cancer and Alzheimer’s have been implicated. Anne Schechinger, senior economic analyst at the EWG, says that it is incredibly difficult to predict toxins. “When it comes to toxins, you can’t just avoid them; you have no way of knowing if a bloom is toxic,” she says. The science is really just getting started.”

The cause of the bloom as well as why it’s getting worse are not completely understood, but we do know what triggers the algal bloom. Besides fertilizers and animal manure runoff, urban stormwater runoff, and septic systems, phosphorus and nitrogen are also factors that contribute to blooms, Schechinger says.

Both animal agriculture, which releases phosphorus in the form of manure, and agriculture, which uses nitrogen as fertilizer, have increased the amount of nutrients in the ecosystem to the point that The Environmental Protection Agency called it “one of America’s most widespread, costly, and challenging environmental problems.”

Climate change has also exacerbated toxic algal blooms. Warming climates contribute to higher air and water temperatures, which fuel the growth of algae. Intense weather events are becoming more common due to climate change, and heavy precipitation often makes things worse. The EPA’s Office of Water reports that climate change may increase the chances of harmful algal blooms through a variety of mechanisms, including: warming water temperatures, salinity changes, increases in carbon dioxide in the atmosphere, changes in rainfall patterns, and increased coastal upwelling.

The spread of the disease can threaten the health of the people in communities along the water. There have been huge fish die-offs and illnesses at beaches this summer due to blooms on Florida’s coasts and lakes. Schechinger says for towns whose economies are based on bodies of water, this can be very damaging. “The Mississippi Gulf Coast had a big bloom last year that shut down most of the beaches, and that had a huge impact on tourism.”

But despite these impacts, there’s no national oversight for outbreaks, and according to Schechinger, monitoring and management at the state level is highly variable. (The EWG uses local news reports to identify outbreaks, which means they’re probably undercounting.) The 1998 Harmful Algal Bloom and Hypoxia Research and Control Act split the responsibility on the federal level between the EPA, which monitors fresh water, and NOAA, which has started to track blooms in marine ecosystems, but no one is looking at the whole picture.

Plus, it’s not easy to track and regulate diffuse pollution that becomes dangerous as it accumulates. In the U.S., we address water pollution through laws like the Clean Water Act, which only covers pollution that comes from a single source, such as wastewater or industrial dumping. The impacts of toxic algal blooms are far removed from the source. For instance, the headwaters of the Virgin River in Utah aren’t particularly close to concentrated agriculture, and they’re far from urban septic systems, but nitrogen and phosphorus still build up in water as they wash downstream.

For Schechinger, the only way to combat non-point-source pollution is to rely on voluntary conservation, which isn’t an effective strategy. Rather than attempting to clean it up once it’s released, she says it would be much more effective to deal with it when it’s created. Algal blooms increase the economic cost of the environment by an estimated $2.2 billion each year.

Many places prohibit swimming or canyoneering for now, and dogs are dying. This problem (welcome to 2021) is not the fault of the people enduring it, and it will only get worse from here.

There is a silver lining, however: more people are paying attention-NOAA, for instance, has just begun forecasting harmful algae blooms for the Gulf Coast of Florida and the Gulf of Maine, and is planning to expand into more places, including the Pacific Northwest, soon. As satellite mapping improves, Schechinger points out that it’s easier to trace pollution plumes back to their sources. The local level is also being regulated: In Minnesota, where Schechinger lives, a new law just went into effect requiring barriers between farms and major waterways.

Starting local and being vocal are the best things individuals can do. Whenever you see algae on your beach or creek, call your local health department or water department. There are fewer inadvertently impacted people when more data points are available, making regulation a wiser choice.

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