Word: nitrogen
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Marine scientists are only now beginning to understand the process by which coastal waters are affected by pollution. The problem, they say, may begin hundreds of miles from the ocean, where nutrients, such as nitrogen and phosphorus, as well as contaminants, enter rivers from a variety of sources. Eventually, these pollutants find their way into tidal waters. For the oceans, the first critical line of defense is that point in estuaries, wetlands and marshes where freshwater meets salt water. Marine biologists call this the zone of maximum turbidity -- literally, where the water becomes cloudy from mixing...
Every year six tons of chlorinated hydrocarbons, 11,500 tons of heavy metals and 1.5 million tons of nitrogen from fertilizers are deposited in the North Sea by rivers and acid rain. An additional 250,000 tons of liquid chemical waste are dumped annually from West German ships into the sea. In Bonn Environment Minister Klaus Topfer last week refused to link man-made pollutants directly to the seal deaths, but he did admit to a "very serious suspicion" that industrial wastes may have played key roles. Topfer has promised to end offshore dumping by the end of 1989. Environmentalists...
...deadly marine impact of nitrogen, mainly from fertilizer runoff, sewage and animal wastes, has been recognized for years. But the E.D.F. study is the first to pinpoint acid rain as an important source of coastal pollution. Any overload of nitrogen feeds marine algae, which bloom into vast growths that block sunlight and deplete the oxygen supply, smothering fish and crustaceans. The E.D.F. reports that 25% of the nitrogen contaminating Chesapeake Bay is the result of acid rain; investigators found similar nitrogen levels in a preliminary study of the coastal waters of New York and North Carolina. The proposed solution: tighter...
Although no one disputes that Chesapeake Bay and other coastal ecosystems are becoming dangerously polluted by excess nitrogen, not all experts agree that acid rain plays a key role. David Cohen, a spokesman for the U.S. Environmental Protection Agency, believes the contribution of nitrogen oxides "is much lower than 25%." EPA scientists suspect that agricultural runoff and the dumping of industrial sewage are far worse culprits...
...Washington by Canadian Prime Minister Brian Mulroney, who has tried unsuccessfully for years to persuade the Reagan Administration to tackle the acid-rain problem. Mulroney last week called the situation a "rapidly escalating ecological tragedy." Even before his arrival, however, Washington rejected a Canadian proposal that the U.S. limit nitrogen-oxide emissions...