The U.S. Environmental Protection Agency (EPA) has 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 sometimes 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. EPA is also recommending how utilities can monitor and treat drinking water for algal toxins and notify the public if drinking water exceeds protective levels.
EPA will issue the final documents containing the health advisory values, recommended monitoring and treatment approaches, and all supporting technical information before summer, which is prime season for algal blooms because of warmer temperatures. 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. “EPA has released health advisory values on algal toxins based on the best available science to ensure the safety of America’s drinking water. We will work closely with our partners at the state and local levels on monitoring, treating, and communicating about the toxins, as well as addressing the sources of nutrients that fuel these harmful algal blooms.”
Health advisories are not regulations, but provide technical guidance to help state and local officials and managers of water systems protect public health. They identify concentrations of contaminants above which adverse health effects are possible and provide testing methods and treatment techniques.
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. The health advisory values are based on exposure for 10 days. While briefly exceeding these advisory levels may not indicate an immediate emergency, EPA recommends utilities use treatment techniques to lower levels as quickly as possible. Steps that can protect the public 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.
· Notifying the public that younger than school age children should not drink or boil the water if levels are above 0.3 micrograms per liter for microcystin and 0.7 micrograms per liter for cylindrospermopsin.
· Notifying the public that no one should drink or boil the water if levels are above 1.6 micrograms per liter for microcystin and 3.0 micrograms per liter for cylindrospermopsin.
EPA will seek input from stakeholders on the recommended actions and other information the Agency can provide to best support states and utilities in addressing algal toxins in drinking water. Based on input, EPA may provide additional technical support documents before the peak of algal bloom season.
EPA worked with Health Canada to develop the health advisories. The World Health Organization has indicated it will use the health advisories developed by EPA to reevaluate global recommendations for levels of algal toxins. As the science on the health impacts of algal toxins continues to improve, EPA will track developments and update recommendations as appropriate.
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.
EPA recently announced it is developing an early warning indicator system using historical and current satellite data to detect algal blooms. EPA researchers will develop a mobile application to inform water quality managers of changes in water quality using satellite data on cyanobacteria algal blooms from three partnering agencies – NASA, NOAA, and the U.S. Geological Survey.
EPA is working diligently with its partners to combat the nitrogen and phosphorus pollution including:
· Providing states with technical guidance and resources to help them develop water quality criteria for nitrogen and phosphorus as part of their water quality standards for surface waters.
· Working with states to identify waters with nitrogen and phosphorus pollution and to develop Total Maximum Daily Loads (TMDLs) to restore the waters by limiting allowable nutrient inputs.
· Awarding grants to states for operating nonpoint source management programs.
· Administering a permit program that restricts the amount of nitrogen and phosphorus released to the environment from point sources, such as wastewater treatment plants.
· Providing funding for the construction and upgrading of municipal wastewater facilities and the implementation of nonpoint source pollution control and estuary protection projects.
· Working with its state and federal partners on the Mississippi River/Gulf of Mexico Watershed Nutrient Taskforce to reduce hypoxia.
· Conducting and supporting research on nitrogen and phosphorus pollution-related topics.
About harmful algal blooms: http://www2.epa.gov/nutrient-policy-data/cyanohabs
About nutrient pollution: www2.epa.gov/nutrientpollution
About research on harmful algal blooms: http://www2.epa.gov/water-research/harmful-algal-blooms-cyanobacteria