[t]here have been some impressive gains in reducing nitrogen pollution of the Chesapeake Bay by municipal and industrial sources, but achieving further reductions will require tougher state permitting and improved oversight of the results, according to a new report from the Environmental Integrity Project (EIP).
EIP found that nitrogen discharges from industrial and municipal sewage treatment plants to the Chesapeake Bay watershed declined significantly in Maryland and Virginia in 2011, thanks to a big public investment in sewage treatment upgrades in both states. Pennsylvania nitrogen loadings from these point sources actually increased 4 percent in 2011, moving that state further from achieving Bay water quality goals that begin to take effect in 2017.
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The EIP report focuses on industrial and municipal point sources – the public sewage systems and industrial plants that account for about 20 percent of the nitrogen and nearly a quarter of the phosphorus that ends up in the Bay. These pollutants promote algae growth and rob the Bay of the oxygen needed to sustain fish and other aquatic life. The Bay clean-up plan adopted by EPA sets targets for reducing nitrogen and phosphorus from these point sources based on "wasteload allocations" that limit annual discharges from the biggest plants.