While most of the major U.S. rivers recently analyzed for chloride con—
centrations have shown little increase over previous concentrations, ponds
and lakes are another story. For example, in a study of Maine roadside farm
ponds from 1966 to 1968, average concentrations as high as 110 mg/l of chlo—
ride were found, where the normal concentration had been 5—10 mg/l [30].
Irondequoit Creek and Irondequoit Bay in Rochester, New York, have
shown a tenfold increase in chloride concentration since 1910. This increase
can be correlated with changes in the stratication pattern of the bay. In the
spring of 1970, complete mixing of the bay did not occur (that is, mixing did
not reach to the very bottom) because of increased density due to salinity.
The fall turnover occurred approximately one month late. During the winter,
at a depth of 21 meters, chloride concentration was as high as 400 mg/l and
bottom water was without oxygen [31].
Salt contamination also poses a threat to ground water supplies. Accord—
ing to 1960 gures, just a little less than one—fth of the total water used in
this country was ground water [32]. Yet each day an estimated ten million
barrels of oil—eld brine are injected underground, and about 200 deep wells
are used for industrial waste disposal [33]. The great danger, of course, is that,
while engineers claim that these liquid wastes are.being stored within safe
geological formations (the area where injection occurs should be completely
surrounded by impermeable rock), no one knows for sure where these wastes
ultimately will travel. The dangers are many [34]: Even seemingly imper—
meable rocks could have unpredicted aws through Which liquids might seep
under pressure; natural disasters, such as earthquakes, could release millions
of gallons of wastes; corrosion or damage of a well shaft would allow liquids
to be forced back up
to the surface. And these are only a few of the possi—
“
bilities. Ground water moves much more slowly than surface water: Ground
ow is usually measured in feet per year, while river ow is measured in feet
per second, and in an underground aquifer the turnover rate for wastes would
be 200 to 10,000 years [35].Thus, a large portion of the water supply avail—
able for future generations could be contaminated.
Turbidity and Sedimentatæ'on. Not all of the impuritîes
found in water
are dissolved substances. Water’s action as an erosive agent accounts for the
large assortment of suspended materials it contains. Suspended particles,vis—
ible to the naked eye or under a microscope, are responsible for the turbidity
or cloudiness of water; unlike dissolved substances, suspended materials even—
tually settle to the bottom of a lake or stream. Sand, silt, clay, organics, algae,
and bacteria are some of the substances that contribute to turbidity. Surface
_runoif is the earth’s most important erosive force. Again, water’s special phys—
ical and chemical properties make this possible: Rocks are split when the wai
te'r which lls their cracks expands upon freezing; because of its high surface
tension, a drop of rain is an effective shattering agent; because of its bouy—
ancy, water can carry eroded materials many miles from their source.
The largest portion of suspended material found in U .S. waters is the re—
Woter Is Not Pure in Nature
51
centrations have shown little increase over previous concentrations, ponds
and lakes are another story. For example, in a study of Maine roadside farm
ponds from 1966 to 1968, average concentrations as high as 110 mg/l of chlo—
ride were found, where the normal concentration had been 5—10 mg/l [30].
Irondequoit Creek and Irondequoit Bay in Rochester, New York, have
shown a tenfold increase in chloride concentration since 1910. This increase
can be correlated with changes in the stratication pattern of the bay. In the
spring of 1970, complete mixing of the bay did not occur (that is, mixing did
not reach to the very bottom) because of increased density due to salinity.
The fall turnover occurred approximately one month late. During the winter,
at a depth of 21 meters, chloride concentration was as high as 400 mg/l and
bottom water was without oxygen [31].
Salt contamination also poses a threat to ground water supplies. Accord—
ing to 1960 gures, just a little less than one—fth of the total water used in
this country was ground water [32]. Yet each day an estimated ten million
barrels of oil—eld brine are injected underground, and about 200 deep wells
are used for industrial waste disposal [33]. The great danger, of course, is that,
while engineers claim that these liquid wastes are.being stored within safe
geological formations (the area where injection occurs should be completely
surrounded by impermeable rock), no one knows for sure where these wastes
ultimately will travel. The dangers are many [34]: Even seemingly imper—
meable rocks could have unpredicted aws through Which liquids might seep
under pressure; natural disasters, such as earthquakes, could release millions
of gallons of wastes; corrosion or damage of a well shaft would allow liquids
to be forced back up
to the surface. And these are only a few of the possi—
“
bilities. Ground water moves much more slowly than surface water: Ground
ow is usually measured in feet per year, while river ow is measured in feet
per second, and in an underground aquifer the turnover rate for wastes would
be 200 to 10,000 years [35].Thus, a large portion of the water supply avail—
able for future generations could be contaminated.
Turbidity and Sedimentatæ'on. Not all of the impuritîes
found in water
are dissolved substances. Water’s action as an erosive agent accounts for the
large assortment of suspended materials it contains. Suspended particles,vis—
ible to the naked eye or under a microscope, are responsible for the turbidity
or cloudiness of water; unlike dissolved substances, suspended materials even—
tually settle to the bottom of a lake or stream. Sand, silt, clay, organics, algae,
and bacteria are some of the substances that contribute to turbidity. Surface
_runoif is the earth’s most important erosive force. Again, water’s special phys—
ical and chemical properties make this possible: Rocks are split when the wai
te'r which lls their cracks expands upon freezing; because of its high surface
tension, a drop of rain is an effective shattering agent; because of its bouy—
ancy, water can carry eroded materials many miles from their source.
The largest portion of suspended material found in U .S. waters is the re—
Woter Is Not Pure in Nature
51