Chesapeake bay pollution
Chesapeake bay pollutionA Look at the Chesapeake Bay
The Chesapeake Bay is America's largest estuary and one of the world�s most productive. The Bay is home to over 2,700 species. It draws water from over 150 rivers, streams, and creaks, receiving roughly 70,000 cubic feet of water every second. That water reflects the surrounding land use activities of the District of Columbia, parts of New York, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia. A total of about 15 million people reside in the Chesapeake Bay water shed. This means that the Bay must process more land-based pollution that most bodies of water.
Water quality and living resources in the Chesapeake Bay that declined steadily over the last several decades have begun to show improvement. Bay grasses, which perform crucial functions in the ecosystem, have increased throughout the Bay. The oyster and blue crab catch, however, continues to dwindle, and some find fish populations have declined. Species, such as striped bass have increased to the point that they are commercially viable again.
The Chesapeake Bay's decline was evident as early as the 1950s. In the late 1970s, state and federal scientists began an extensive study to determine the reasons for the Bay's decline. Three major problems were identified; excess nutrients from wastewater, agricultural lands, and developed land; sediment in runoff from farms, construction sites, and eroding lands; and possible elevated levels of toxic chemicals.
Nitrogen and phosphorus are considered good things because they support the bottom of the food chain. But in recent years the Chesapeake Bay has been receiving too much of these nutrients. The excess nutrients have created large blooms of microscopic plants called phytoplankton. The growth of phytoplankton has cut off the supply of light to underwater grasses. The underwater grasses are essential part of the Bay�s ecosystem because they provide a habitat for many species and help filter the water. Pollution has reduced the grasses to only 10% of their historic levels, from 600,000 acres to around 65,000 acres today. Another problem occurs when algae dies and begins to decompose. The process of decomposition removes dissolved oxygen from the water and turns large sections of the Bay into dead zones where life can not be supported.
The presence of phosphorus in the Chesapeake Bay has been receiving extra attention because of its possible role in outbreaks of the toxic microbe pfiesteria. Pfiesteria is suspected to cause lesions on fish in the Bay. There are currently studies underway searching for a correlation between fertilizer runoff and the outbreak of Pfiesteria.
Toxins, such as the heavy metals mercury, cadmium, copper, lead, zinc; and pesticides, dioxins, polychlorinated biphenols (PCBs), polynuclear aromatic hydrocarbons (PAHs), and many other chemicals have been identified as a potential threat to the Bay. Toxic substances are poisonous to humans and other living things and have been known to cause a wide range of negative health effects. There are over 70,000 chemicals currently...
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