that we expected to observe and study during various seasons and over a period 

 of several years. Because of man's omnipresent interference with everything 

 natural, no lake, pond, river, marsh, bog or swamp could be designated as having 

 never been disturbed or the way Mother Nature would have wanted it without 

 man's disturbing and polluting influence. We early forewent the idea of establish- 

 ing "controls," and decided, instead, to accept conditions as we found them to 

 exist. We realized that pollution had become so thoroughly spread, and it had 

 unquestionably affected or so changed the various ecosystems that it would be 

 impossible to determine what species comprised the original vegetation of most 

 of the area studied. 



We have tried to summarize below the primary water pollutants and to point 

 out some of the deliterious effects of their pollution upon the environment. These 

 data are a combination of personal observations and those taken from numerous 

 articles, papers and books that have been published on the subject during the last 

 few years, but primarily from an article by Young (1970). 



Doubtlessly, the chief causes of water pollution are inadequately treated sewage 

 and manufacturing wastes, oil from ships and drilling leaks, fertilizer runoff, 

 pesticide residues and acid drainage from mines. These wastes, plus sediment, have 

 ruined practically every major river in the Nation, and have converted them from 

 what was once unadulterated assets to the Nation into liabilities and a real menace 

 to much of the world's population. The pollutants they transport to the sea are 

 endangering our estuaries, wetlands and coastal waters — nurseries for most of our 

 commercially important fish and shellfish. 



Though chemical fertilizers have greatly increased crop production, and long- 

 lasting pesticides have achieved their goal in protecting our crops, wind and rain 

 have carried these pollutants into our rivers, lakes and ponds where the fertilizer, 

 plus sewage, has contributed to an enormous overgrowth of algae. This over- 

 growth of algae in the upper zone suffocates the lower layers of algae by depriving 

 them of light for photosynthesis. This lower layer dies and decays, and in doing 

 so uses oxygen that is needed by fish which, in turn, die. The pesticides, upon 

 reaching the oceans, are carried up the food chain through fish to thwart the 

 reproduction of eagles, ospreys, pelicans and other fish-eating birds. 



Mercury waste has been flushed into many lakes and rivers by industry. Bacteria 

 convert some of it into highly toxic methyl mercury, which is passed along the 

 food chain into fish, such as sword and tuna, that man now can not eat with 

 knowledge of absolute impunity. Various mercury compounds used in agriculture 

 are known to have poisoned game birds in many parts of the world. 



Stripping the forests for lumber, excessively wide highways and our paralytic 

 housing developments encourage soil erosion and the steady erosion of one of our 

 major sources of oxygen-producing greenery, while strip-mining scars the country- 

 side and allows mine acids to wash and spread out to kill adjacent and surrounding 

 vegetation. 



Our rapidly increasing nuclear power plants create thermal pollution in the 

 water used for cooling. The heated water holds less oxygen and can thus disrupt 

 the life cycle of aquatic organisms. 



Oil spills foul beaches throughout the world, as can be attested by anyone who 

 has walked along practically any of our beaches during the last several years. 

 The blotches of black oil that accumulate on the bottom of feet is only a harmless 

 visual pollutant compared to the toxic chemicals released that can kill fish and 

 birds, and, by forming a film over the water, oil can inhibit the intake of oxygen 

 by the water to smother life on the bottom. Millions of tons of petroleum each 

 year are flushed from ships, spilled at fueling ports, and poured into the sea 

 from leaking or runaway offshore wells and wrecked tankers. 



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