A U.S.-Canadian report says parts of the Great Lakes are suffering from excessive nutrients such as phosphorus, which promote growth of algae blooms that can damage ecosystems and human health.
In a biennial lakes report released Wednesday, The International Joint Commission calls for stepped-up research and monitoring to deal with eutrophication (YOO'-truh-fuh-kay-shun), or over-abundant plant growth in nearshore areas.
It may be caused by substandard wastewater and septic systems, manure and fertilizer runoff from farms and climate change, which causes more intense storms. The report urges governments to promote restoration of wetlands that filter out pollutants before they enter the lakes.
It also says urban runoff is degrading water quality at many beaches and calls for improved methods of determining when beaches should be closed to protect human health.