In our series, Ten Threats to the Great Lakes, we’ve been looking at environmental problems affecting the health of the lakes. The Great Lakes Radio Consortium’s Sarah Hulett reports on lawn fertilizers and their impact on the Lakes.

The Great Lakes Radio Consortium's Shawn Allee looks into how rain that washes off concrete and asphalt in cities and suburbs poses just as big a threat to the Great Lakes as pollution from a factory pipe.

The Great Lakes Radio Consortium's Lester Graham reports on how "nonpoint source pollution" might be turning some shallow waters in the Great Lakes into dead zones.