9. PCB Pollution in the Hudson
Though PCB discharges to the Hudson ended in 1977, significant amounts of this toxic chemical remain in the river's bottom. The PCBs enter animals and fish, building up to concentrations high enough to harm these creatures and people who eat them. Along the river between Hudson Falls and Troy, PCB contamination requires that anglers release all fish that they catch. Cleanup of PCBs in the upper Hudson began in 2009, overseen by the U.S. Environmental Protection Agency.