Algae blooms have been increasing in number on Lake Erie for the past few years as a result of man-made causes and climate change. This problem has affected both the United States and Canada, which are on either side of Lake Erie: 11 million people rely on the lake for drinking water. This phenomenon is particularly troubling because of the high population of people who live along the shores, as it causes health concerns that result from the toxicity of these algae blooms.
What are algae blooms?
This poisonous blue-green algae is also called Microcystis. It propagates during the summer months since Lake Erie is the shallowest of the Great Lakes and warms up faster than the deeper lakes.
Algae blooms create a thick surface layer and depletes the oxygen in the deeper water creating a condition called hypoxia. When the algae decays, this creates a dead zone that is harmful to fish and wildlife. Hypoxic conditions can likewise be exacerbated by climate change since summers start earlier and last longer.
Aside from the ecological dangers, they also clog water intake, decrease water quality and pose health risks to humans, pets and wildlife. Exposure to the toxins produced by the algae can cause skin rashes, headaches, fever, diarrhea, nausea, vomiting and liver failure.
Toxic algae produces a strong, nauseating, and pungent odor that smells like rotting fish or an open sewer. It also increases the E. coli bacteria concentrations which are harmful when ingested by humans or pets. It can also contain cyanotoxin, which can cause skin irritation, respiratory difficulty and gastrointestinal distress.
The International Joint Commission created the Lake Erie Ecosystem Priority (LEEP) in 2011 as a result of the largest algae bloom ever recorded. During this time, 1/6th of Lake Erie was covered by algae blooms tainting the drinking water for 2.8 million people.
What are the major causes of algae blooms?
The huge influx of phosphorus into the lake is the major contributor to this phenomenon. Phosphorus gets washed into the lake via fertilized farmlands, lawns and gardens, construction, stormwater runoff, deciduous tree leaves and pet waste.
The summer months produce the perfect environment for algae to thrive. Heavy downpours can also contribute to increased growth. The algae feed on phosphorus that is a result of irrigation runoffs from farms that use ammonium phosphate as fertilizer. Man-made activities and climate change create a perfect storm for algae propagation. The fertilizer that was meant for farmland crops end up in the lake and results in the overgrowth of algae.
What can be done about it?
Earlier phosphorus removal methods have involved the use of chemical precipitants but emerging technologies may provide a more natural solution by using bacteria that feast on phosphorus. New advancements developed at the University of British Columbia enabled the crystallization of fertilizer granules in pure form eliminating phosphorus and nitrogen. The product was launched in the market under the name Crystal Green.
In the case of biosolids, a technology developed at the University of Waterloo uses low-pressure, low-temperature thermal hydrolysis to allow wastewater plants to convert what would have been Class B biosolids in Class A fertilizer. The process also eliminates pathogens and results in high quality fertilizer that does not need to be overapplied to agricultural lands. The final product manufactured under Lystek International can be injected four or five inches into the soil, greatly reducing nutrient runoff.
Regulatory requirements have also been enacted at the state or provincial level to manage the application of nutrients. Ontario, New York State, Michigan, Ohio and Pennsylvania control the use of manure on frozen ground to limit run-off. Liquid or semi-liquid manure, which contains phosphorus, cannot easily penetrate ice and the possibility of run-off into bodies of water is higher when the snow melts.
The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) has identified environmentally sensitive areas and has mandated buffers and setbacks when applying biosolids. In June 2015, the governors of Michigan and Ohio and the premier of Ontario signed an agreement to reduce phosphorus inputs to the western waters of Lake Erie by 40 per cent over the next 10 years, with an interim goal of a 20% reduction by 2020.
If you are a municipality in Ontario and in need of a biosolids management solution, please feel free to contact us at 1 (877) 479-1388.
Sources:
Science Education Resource Center at Carleton College
Inside Climate News
FEECO International