There's good news and bad news about water-quality trends in the
nation's rivers. The good news is that bacteria levels are decreasing
because of new sewage treatment plants, and lead concentrations are
generally decreasing because of reduced lead in gasoline. The bad news
is that the levels of toxic arsenic and cadmium are increasing,
probably from coal combustion and the smelting of metals; levels of
salt are increasing, probably from the salting of roads; and levels of
nitrate nitrogen are up, probably from increased use of fertilizer on
crops and from fossil fuel (coal and oil) combustion.
These are the conclusions of a new study of water-quality trends in the
nation's river system, published in SCIENCE magazine March 17, 1987
The nation has spent over $100 billion on new sewage treatment plants
during the past 15 years and these have curbed bacteria in our rivers.
Sewage treatment plants control "point sources" of pollution--specific
pipes that introduce contaminants into waterways.
However, the study shows that water quality is widely affected by "non-
point sources" of pollution--sources of pollution that are not a single
pipe. These include runoff from farmers' fields, from city streets and
rural highways, and chemicals spewed into the air from smoke stacks
(chemicals that later rain down onto the earth and are washed into
streams). The $118 billion needed for additional sewage treatment
plants will do nothing to affect these "non-point sources" of pollution.
The study looked at 24 measures of water quality taken at 380 sampling
stations in two nationwide monitoring networks during the period 1974-
1981. The trends are important because they reveal that "end of the
pipe" solutions are not doing the job they were designed to do:
restoring the quality of the nation's waterways will involve structural
changes in the way the nation does business. This is a conclusion the
government, and traditional environmentalists, have in the past refused
Fertilizer application rates increased 68% between 1970 and 1981. This
trend must be viewed in the context of American farms falling into the
hands of large farming corporations cooperating with, or directly owned
by, American oil and chemical producers. One result of this increased
fertilizer application is that nitrate loads increased significantly in
East Coast estuaries, the Great Lakes and the Gulf Coast during the
The other major contributor to nitrate loads is coal combustion. Here
again, new ways of doing business will be needed if we are to control
this menacing problem, but the political will for making the necessary
changes seems to be lacking. The federal EPA seems eager to avoid
controlling the mining, smelting and power companies responsible for
the major coal-burning plants.
The nitrogen loading of East Coast estuaries, the Great Lakes and the
Gulf Coast increased 20% to 50%, 1970 to 1981, and the trend is clear.
Reversing the trend will not be easy, but it will be important to try.
Nitrogen is the limiting factor on eutrophication in many estuaries,
and the health of these especially-productive areas (e.g., Chesapeake
Bay) is jeopardized by nitrate nitrogen. Acid rain is not the major
reason for needing controls on coal; it is merely one more symptom of a
serious and widespread malady in the American economy: our failure to
see that an industrial enterprise based entirely on fossil fuel
combustion no longer makes sense.
Coal combustion and the smelting of nonferrous metals has led to
another problem: measurable increases of toxic arsenic and cadmium in
the nation's rivers. This comes directly from coal burning and from non-
ferrous smelters; (the arsenic and cadmium escape from the smoke stack,
then rain down to earth). Arsenic is a famous poison, but cadmium is
far more dangerous. Cadmium has been shown to cause heart disease in
humans by making the arteries hard and inflexible. Cadmium accumulates
in the body throughout a person's life. It is a powerful and insidious
chronic poison and its increasing presence in the nation's rivers is
very unwelcome news. Arsenic and cadmium also enter the nation's
waterways by leaching out of the fly ash stored at coal burning plants
and at nonferrous smelters, so fly ash is not a benign waste and it
should be tightly regulated. It is not.
Salting of roads is a widespread practice. Naturally the salt has to go
somewhere and it goes into the nation's rivers and groundwater. Most
people would agree that it makes little sense to throw salt into our
fresh water supplies. Yet in America between 1950 and 1980, our annual
use of salt on roads increased twelve-fold; from 1970 to 1981 the salt
levels in the nation's rivers increased 30%.
Probably the most important and far reaching conclusion of this study
is that the nation's water quality monitoring networks don't yield the
data we need so we can understand what's really going on. For example,
lead is decreasing in most of the nation's rivers, yet it is INCREASING
along the Texas Gulf coast and in the lower Mississippi basin. The data
are too crude to reveal why this is so. The study shows that--20 years
into the "environmental crisis"-Americans are still served by a water
quality monitoring system that gives only crude indications of gross
trends. It is part of our government's grand failure to develop a
database of environmental baseline information.
For further discussion of this study, see Science News April 4, 1987,
Descriptor terms: water pollution; water; rivers; hazardous waste;
arsenic; cadmium; smelting; salt; nitrate nitrogen; studies; sewage
treatment; non-point sources; fertilizer; estuaries; great lakes; gulf
coast; nitrate; coal; monitoring; agriculture; lead; salt; roads;
highways; fly ash; electricity; statistics;