Nature Bulletin No. 401-A   January 9, 1971
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation

****:STREAM POLLUTION

The pollution of surface waters in the United States is one of man's 
most shameful and dangerous crimes against himself. It is ruining one 
of the nation's basic resources by rendering water unfit for human 
consumption and unsuitable for many industrial or domestic uses. 
Pollution is particularly alarming near most big cities, but, emptied into 
rivers and creeks, other communities may feel its effect a hundred or 
more miles downstream. Even in remote or rural regions, it originates 
as wastes from mines, paper mills, canneries and creameries .

A lot of the pleasure of living is taken away because our streams and 
lakes are fouled and spoiled for bathing, boating, fishing and other 
recreations. Further, the health hazard is very real. Unless such waters 
are boiled or chlorinated there is danger from typhoid, dysentery and 
many other diseases.

The most common and offensive effects of pollution arise from 
household sewage and wastes from the processing of foods: packing 
plants, canneries, distilleries and the like. This decaying organic matter, 
as it becomes putrid, stimulates an enormous multiplication of water 
bacteria and a host of other small plant and animal life which use it as 
food. Like other living things, most of these "breathe" and use up the 
oxygen dissolved in the water -- faster in warm weather, slower in 
winter -- often reducing it to the point where fish, for example, must 
retreat into cleaner water or suffocate.

Unfortunately, oxygen is but slightly soluble in water, reaching only 7 
or 8 parts per million in summer and somewhat more in cold weather, 
even in clean water. At least half this amount is necessary for the 
survival of most kinds of gamefish and panfish, as well as for the 
minnows, crayfish, insect larvae and other animals on which they feed. 
Fish like carp, goldfish, buffaloes, bullheads and gars can live in 
polluted water so long as the oxygen does not go too low, but it may 
weaken them until even they fall prey to fish diseases. Among the small 
animal life there is also a wide range of tolerance to pollution: some 
very sensitive, others hardy. Even when the oxygen is completely 
exhausted, sludge worms (which look like miniature earthworms) may 
become so numerous that they look like red pile on a gray rug.

A clear fresh stream, receiving a heavy dosage of sewage, first becomes 
turbid and murky; then it bubbles, gives off foul odors and shows 
floating sludge; then if not further polluted, it slowly improves 
downstream -- finally becoming clear and fresh again. This process is 
called natural purification. Sewage treatment plants merely speed up 
this natural action and remove the sludge so that damage to streams and 
lakes is held to a minimum. This sludge, properly processed, can be 
used to improve the soil on lawns, gardens and fields. Pollution by oil 
wastes and by industrial wastes such as acids, cyanides, copper and 
arsenic, may poison aquatic life directly and make waters so unsafe for 
human use that they require special treatment.

Most cities and towns use about 100 gallons of water per person per 
day. This is in addition to industrial uses, which are much greater. It 
requires 55 gallons to make a pound of steel, 1000 gallons for a barrel 
of aviation gasoline and from 100 to 200 gallons for a pound of rayon. 
Water is truly a critical material in modern civilization and must be 
conserved for our very existence. Our health and our wealth depend 
upon clean waters.

Unlike the weather, something can be done about pollution. Let's do it.