The U.S. Environmental Protection Agency (EPA) today issued health advisory values that states and utilities can use to protect Americans from elevated levels of algal toxins in drinking water. Algal blooms in rivers, lakes, and bays produce harmful toxins.
Because utilities often use these water bodies as sources of drinking water, EPA has determined algal toxin levels in tap water that are protective of human health based on the best available science.
Last August a harmful algal bloom in Lake Erie left half-a-million residents of Toledo without drinking water for two days.
EPA estimates that between 30 and 48 million people use drinking water from lakes and reservoirs that may be vulnerable to algal toxin contamination.
“Nutrient pollution and harmful algal blooms are among America’s most serious and growing environmental challenges,” said EPA Administrator Gina McCarthy.
The health advisory values for algal toxins recommend 0.3 micrograms per liter for microcystin and 0.7 micrograms per liter for cylindrospermopsin as levels not to be exceeded in drinking water for children younger than school age.
For all other ages, the health advisory values for drinking water are 1.6 micrograms per liter for microcystin and 3.0 micrograms per liter for cylindrospermopsin. Potential health effects from longer exposure to higher levels of algal toxins in drinking water include gastroenteritis and liver and kidney damage.
Steps that can protect yourself from algal toxins in drinking water include:
- Watching for harmful algal blooms in water bodies used as a source of drinking water.
- Monitoring source water and drinking water for detections of algal toxins.
- Treating drinking water as necessary to reduce and remove algal toxins, including a decent water filter system.
Nutrient pollution of water is one of America’s most widespread, costly and challenging environmental problems, caused by excess nitrogen and phosphorus in the air and water. More than 100,000 miles of rivers and streams, close to 2.5 million acres of lakes, reservoirs and ponds, and more than 800 square miles of bays and estuaries in the United States have poor water quality because of nitrogen and phosphorus pollution.
Too much nitrogen and phosphorus in water can cause algal blooms, which can turn harmful to humans if they produce toxins. People can become sick from harmful algal blooms if they play or swim in a polluted water body, consume tainted fish or shellfish, or drink contaminated water. Harmful algal blooms can also create dead zones in water, killing aquatic life, raising treatment costs for drinking water, and hurting businesses and jobs that depend on clean water.