A report says new antibiotic-resistant pathogens, airborne mercury, and urban sprawl are threatening the health of the Great Lakes.
The report was released today by the International Joint Commission, a US-Canadian organization that monitors the lakes.
The report says the new threats endanger the health of millions of people who live around the bodies of fresh water.
The commission says there's been a general improvement in Great Lakes water quality over the past 30 years.
But it says that new and emerging threats require urgent attention.
One issue is the use of antibiotics in livestock and humans, which the report says could lead to contaminated drinking water.