Marine Pollution in the United States: Significant Accomplishments, Future Challenges

Marine Pollution in the United States: Significant Accomplishments, Future Challenges has been prepared by UMCES' faculty experts for use by the Pew Oceans Commission in evaluating national oceans policy regarding environmental quality and marine resources. The Pew Oceans Commission is an independent group of distinguished Americans conducting a national dialogue on the policies needed to restore and protect living marine resources in U.S. waters. The report on marine pollution is the first in a series being developed to inform the Commission's deliberations. The Center will also assist the Commission by bringing together experts on coastal development and habitat change to provide similar technical assessments. Coordinator: Dr. Donald F. Boesch. Direct discharges of pollutants into the ocean and coastal waters has been greatly reduced over the past 30 years. Ambient levels of some persistent toxic pollutants, such as DDT and PCBs, have been decreasing in most U.S. marine environments. However, pollution from land runoff is largely unabated, and in some cases it has increased. As a result, diffuse sources now contribute a larger portion of many kinds of pollutants than the more thoroughly regulated direct discharges. Overenrichment of coastal ecosystems by nutrients, particularly nitrogen, has emerged as the most widespread and measurable effect of pollution on marine ecosystems. Excessive nutrient levels may result in serious depletion of the dissolved oxygen supplies needed by marine animals, loss of habitat and algal blooms. Two-thirds of the surface area of estuaries and bays in the contiguous U.S. suffers one or more symptoms of overenrichment. Because a majority of the nutrients in most regions now come from diffuse sources rather than direct discharges, reversing coastal eutrophication will require management strategies for watersheds reaching far inland from the coastal environment. Feasible measures include advanced treatment of municipal wastewaters, reduction of nitrogen oxide emissions from power plants and vehicles, control of ammonia missions from animal feedlots, more efficient use of fertilizers and manure, and restoration of wetlands and floodplains that act as nutrient traps.

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