Associate Professor Chul Park of the Civil and Environmental Engineering Department commented quite extensively in a news story written by staff writer Sarah Robertson in the Daily Hampshire Gazette about a potentially harmful algae bloom affecting Lake Metacomet in Belchertown. Park said that such blooms are usually caused by high temperatures and an imbalance of nutrients in the water.
Park specializes in the study of algae and microbial processes. “Usually algal blooms are caused by an increase in temperature, most importantly by the imbalance of nutrients, especially nitrogen and phosphorous,” Park said in the Gazette. “With increasing temperatures, we tend to see more events of harmful algal blooms.”
Park also noted that the blue-green algae blooms have potential to be toxic, but are not always.
“Even if you see them growing in the water, that does not mean they are producing toxins,” Park said. “Under very limited conditions and environmental distress they produce toxins; it is not very well known why.”
The Gazette piece explained that chemical tests can determine the toxicity of a specific type of bacteria, but, before that is confirmed, Park says lake recreationists should exercise caution. Touching the algae, if they are toxic, can cause rashes or irritation.
According to the article, nutrients in the form of nitrogen and phosphorous can come from a variety of sources, including leaking septic systems, lawn fertilizer, stormwater, or agricultural runoff. Globally, blooms of cyanobacteria are on the rise as warmer temperatures, driven by climate change, hasten the growth. Last year, Florida’s governor declared a state of emergency and beaches were closed when algae blooms spread from Lake Okeechobee to nearby estuaries, and more than 100 people fell ill after swimming in Utah’s largest freshwater lake.
“Generally speaking, if we see their concentration elevating it generally causes concern,” Park said about algal blooms.
Park recommended identifying the point source of the nutrient overload and stopping it there, instead of removing just the bacteria. One potential source, he said, could be any wastewater treatment facilities releasing water upstream, since the cleansing process removes pollutants, but not the phosphorus and nitrogen found in organic materials.
Park added that “If there are a lot of septic systems in the town, these nutrients can eventually leach out into groundwater, which will eventually enter into the lake water. We also know these days more nitrogen enters from the atmosphere too.”
Algae blooms are especially common in small ponds and lakes that get warm in the summer while water levels are low and stagnant, Park said. “Once this starts happening, it’s quite difficult to control, so it may need some kind of comprehensive understanding of the sources.” (August 2018)