In short
This article analyzes how harmful algae affect multiple industries and the challenges they pose.
- Water is a vital resource for many companies, so careful management is necessary to achieve optimal quality.
- One of the problems faced by numerous companies in this process is the presence of microalgae in high concentrations.
Harmful algal blooms, or HABs, have financial and operational consequences across a wide range of industries. However, the challenges faced by each industry are different. From health risks to drinking water consumers to exceeded TSS levels in cooling ponds at power generation facilities, algal blooms are a growing problem that must be addressed.
1. Drinking Water
Water in raw water reservoirs is often stagnant. This lack of water circulation promotes the proliferation of harmful algae in these industries, which compete excessively with other organisms in the ecosystem and, as a result, create large algal blooms (ALBs).
Excessive growth of cyanobacteria, formerly called blue-green algae, and green algae in a drinking water reservoir can have detrimental consequences for water quality. Some algae can produce geosmin and MIB, giving the water an “earthy” and “musty” taste and odor, which can cause consumer complaints. In addition, cyanobacteria are capable of producing cyanotoxins and other toxins that can cause health effects in people exposed to contaminated water. Short-term exposure during recreational activities can cause headaches, pneumonia, and respiratory and gastrointestinal problems. Long-term exposure to these toxins can cause liver and kidney failure, and even neurodegenerative diseases such as Alzheimer’s.
Algal blooms also cause a number of operational problems for water treatment plant operators, such as clogging filters. Drinking water plant managers are advised to monitor the species of algae present, dissolved toxins, and cell counts using appropriate techniques and monitoring. To do this, regular samples must be taken to assess the situation and protect public health. Based on this information, if levels exceed the established values for the concentration of total microcystins in drinking water, the administration may implement:
- Alert levels
- Control measures or
- Water treatment
2. Power generation
In this sector, harmful algae represent a growing operational problem. The water source for cooling ponds differs depending on the facility and often includes river water or treated wastewater effluent. To remove impurities, such as high levels of dissolved solids, cooling ponds discharge a portion of the cooling water into the environment. In most countries, organizations such as the U.S. Environmental Protection Agency (EPA) set effluent limitations to control the discharge of potential pollutants, including nutrients such as nitrogen and phosphorus, into the environment. Parameters subject to permit limits, such as NPDES regulations, typically include pH, biochemical oxygen demand (BOD), and total suspended solids (TSS).
A common cause of noncompliance with these standards is the presence of HABs, making their control one of the most effective methods for meeting discharge standards. The growth of microalgae, including harmful algae species such as blue-green cyanobacteria, in cooling water can also block pumps and affect circuits, posing a threat to the system and increasing water toxicity.
3. Wastewater
Excess nutrients from stormwater runoff and fertilizers, stagnant and shallow water, warm temperatures, and other factors contribute to increased algae growth in wastewater lagoons.
Algal blooms, varying in type and color, increase biochemical oxygen demand (BOD), pH levels, and total suspended solids (TSS). Having High BOD indicates biological contamination and depletion of dissolved oxygen in the receiving water. High total suspended solids levels indicate a significant number of larger particles in the water, which can clog irrigation systems such as filters and distribution pipes.
High TSS levels also further deplete the water of dissolved oxygen. To reduce the impact of wastewater discharges on the environment and aquatic life, the EPA (Environmental Protection Agency) established discharge limits for BOD, TSS, and phosphorus in effluents. To comply with the National Pollutant Discharge Elimination System (NPDES) permit, which sets technology-based effluent limits to protect the water quality standard permit, it is essential to control algal blooms and, consequently, reduce harmful pollutants entering surface waters.
4. Agriculture
Nearly 60 percent of all freshwater withdrawals worldwide are used for irrigation. This includes water that benefits agriculture or crops, one of the industries most affected by harmful algae. Water quality depends on the source, which can include dams, recycled water, and rivers. According to the U.S. Environmental Protection Agency, there are more than 2.2 million farms in the United States alone.
Health and safety risks
There are several risks associated with using water contaminated with cyanobacteria for irrigation purposes. Field workers are at risk of inhaling toxins when using a sprinkler irrigation system with water affected by harmful algae. Symptoms of exposure include skin rash, vomiting, shortness of breath, and, in rare cases, death. In addition, pets that come into contact with this water may also be affected. When crops are exposed to microcystin concentrations, this toxin can accumulate to levels where even a small portion would exceed the WHO guideline value for tolerable levels.
Health and crop impacts
Therefore, it is advisable not to use water contaminated with blue-green algae on crops grown for human and livestock consumption. For example, dried algae cells on salad leaves can remain toxic for several months. Consumption of contaminated drinking water can cause liver damage, seizures, and sudden death in livestock, even affecting the nervous system of animals. Exposure to contaminated water can lead to decreased milk production in cows and decreased egg production in chickens. Algae can also pose an operational and financial problem by clogging irrigation systems and thus limiting their functionality.
5. Lakes
Harmful algal blooms are more severe, occur more often, and last longer. These are the results of a study on algal bloom trends over 30 years in 71 large lakes in 33 countries around the world. “We found that the maximum intensity of harmful algal blooms in summer increased in more than 68 percent of the lakes, but decreased statistically significantly in only six of them,” explained Michalak, the study’s author. “This means that algal blooms are actually spreading and becoming more intense due to warming and climate change.”
Budget cuts related to the COVID-19 pandemic forced many US states and countries to reduce testing and monitoring of algal blooms. Based solely on information published by the media, we can say that this year more than 400 bodies of water in the United States, including lakes such as those in Toledo, were contaminated by harmful algal blooms. Authorities closed eighty-seven percent of these recreational lakes because dangerous toxins such as Microcystis posed serious health risks and made it unsafe to swim, boat, or even walk near an infected lake.
6. Aquaculture
Toxic algal blooms in aquaculture, one of the industries most affected by harmful algae, can cause indirect toxicity in shellfish and fish through changes in water quality, direct toxicity, and changes in taste. Toxins, including those produced by species such as Pseudo Nitzschia, can also kill farmed animals or slow their growth rate.
The breakdown of biomass from algal blooms depletes dissolved oxygen, which can lead to mass deaths of cultured organisms. Harmful algal blooms can affect organisms such as clams, mussels, oysters, and scallops that feed on toxic phytoplankton and accumulate harmful toxins.
Consuming contaminated fish and shellfish can cause symptoms within 15 minutes to 10 hours. Mild symptoms include numbness in the legs, face, and arms, loss of coordination, and dizziness, while more severe cases can lead to paralysis and respiratory failure. Paralytic shellfish poisoning caused by consuming shellfish contaminated with HABs is a life-threatening illness. Researchers have studied the extent and manner in which these toxins affect food safety. Concerns about food safety and the death of cultivated organisms lead to estimated losses of $40 million per year in the United States alone.