Historically an estuary was thought to be immune to environmental problems. Shorelines have been used for centuries as a disposal ground for sewage and industrial waste. It was originally thought that the dilution of wastes in vast ocean waters would render them harmless. Because of this rational and historical lack of concern coastlines are some of the most threatened environments on the planet. Only 300 years ago Long Island Sound was teeming with oyster beds but due to anthropogenic activity loss of these organisms and their ability to increase water clarity now prevents sea grass and seaweed beds from colonizing. Over-harvesting, pollutants and introductions of invasive species are now the most pressing issues.
Anthropogenic sources of heavy metals in Long Island Sound have accumulated from a long history of industrialization. Long Island Sound is bordered by large cities such as New York, Bridgeport, and New Haven. Rivers such as the Housatonic, Thames, and Connecticut drain extensive inland areas of the New England states into the sound.
Sediments in the sound are known to be a repository for contaminant metals. New Haven Harbor is a bay located in the central region of Long Island Sound. It is the most active port in the state, which plays a role in keeping Connecticut recognized on the global market. New Haven harbor is responsible for the shipping of petroleum products, pharmaceuticals and building supplies. It is an industrial harbor with oil storage tanks, sewage treatment plants and electrical power plants. New Haven harbor is also important in the growth and cultivation of natural resources such as the Eastern oyster
and the blue mussel
. Studies have shown that sediments in the inner harbor have a higher concentration of pollution than the rather unpolluted sediment of the outer harbor. This is due to past and current discharge of municipal and industrial wastewater.