Are the Great Lakes getting cleaner or dirtier? The answer is mixed. Pollutants that were top priorities in the 1970s like phosphorus and PCBs have been on the decline while new contaminants have worsened. The loss of wetlands, which filter pollutants and provide habitat, and increases in pollution from poorly planned development are causing new problems. As the successes of the 1970s showed, the key to further progress is citizen activism. Government only follows where citizens lead.