other solids settle
the bottom of a stream, they can smother bottom life. In
one experiment, freshwater mussels were smothered when one quarter to one
inch of silt was allowed to settle over either a sand or a gravel bottom habitat
to which they had become adapted [38]. Silt sometimes causes algae to
occulate (that is, to make them stick together) so that they no longer oat.
When the algae sink to the stream bottom, they increase the amount of dxy—
—
gen available to the increased number of bacteria that degrade this material
[39].
The same qualities that make water effective as an erosive agent make it
useful to people as a cleaning agent. A group from Marquette University re—
ported to the 1970 federal hearings on phosphates and eutrophicaüon on the
difference in cleaning power between a non—phosphate detergent (Heinecke’s
B—5), a phosphate detergent (Tide), and plain water. They took diap_ers soiled
With garden dirt and barbecue sauce and dried them, and then placed them in
washing machines. Plain water
better than either of the two deter—‘
.
gents. Even taking into acCount that no tests “for greasé (soap or detergents
*
are essential to remove grease) or bacteria Wer—e.made, the experiment illu.e—
_
trated water’s important role in cleaning—à proCess that is usually attributed
_
—
to the cleaning agent alone “[:40]. ,
.
"
»
_…
Ÿ
:
'
w
Cases.
that-become dissolved in water -origirrâte, from twomam :
,
sources: the atmosphere-and the byproducts of the metàbolisms of 1iÿing»ôf—
“
gam'sms. The air contains 78 percent nitrogen, 21
.
—
percent carbon dioxide. The amountof'each ofieségasesjthatwrbefound _
.
in water depends on the relative amount of that “gas in the atmosphere,
,
=
whether or not the gas
reacts With water, and, its sdubiütyboefjciêñï’î“(the
liters of gas absorbed;by one liter of water at 0°C and one
sure). Oxygen and nitrogen have c‘omparatively low solubility coefcients
_
(0.049 for oxygen and 0.024 for nitrogen) and are not found in large amounts
in the water. The solubility coefcient of carbon dioxide, on the other hand, is
1.713. In addition, carbon dioxide reacts with water. Thus, compared to the
small amount of carbon dioxide found in the air, a relatively large proportion
is found in the water. Biological processes
contribute gases
to the water also.
Oxygen is a product of photosynthesis; carbon dioxide is a product of respira—
tion; and hydrogen, methane, ammonia, and hydrogen sulde are all products
of the bacterial decomposition of organic matter.
pH and Carbon Dioxide. The pH of any body of water describes its degree of acidi_ty or alkalinitÿ. The pH scale, which ranges from 0 to 14, mea—
sures the concentration of hydrogen ions (hydrogen atoms with a positive elec—
tric Charge) and hydroxyl ions (an oxygen and a hydrogen atom With a
negative charge). If a. solution has equal numbers of hydrogen and hydroxyl
«on the pH scale, or 7. More hydroxyl ions in—
crease’s,thtæ;àlkalinity, (The: scale is logarithmic, so a pH of 5 isten times more
_
acid than
of 9 is ten times more
pH Off—8.)
_
.
Pure,,diStled?watenhaspaf—pH of 7, and the pH of most naturalwæitersis 7
9 j
7
_
…
f
—
‘
the bottom of a stream, they can smother bottom life. In
one experiment, freshwater mussels were smothered when one quarter to one
inch of silt was allowed to settle over either a sand or a gravel bottom habitat
to which they had become adapted [38]. Silt sometimes causes algae to
occulate (that is, to make them stick together) so that they no longer oat.
When the algae sink to the stream bottom, they increase the amount of dxy—
—
gen available to the increased number of bacteria that degrade this material
[39].
The same qualities that make water effective as an erosive agent make it
useful to people as a cleaning agent. A group from Marquette University re—
ported to the 1970 federal hearings on phosphates and eutrophicaüon on the
difference in cleaning power between a non—phosphate detergent (Heinecke’s
B—5), a phosphate detergent (Tide), and plain water. They took diap_ers soiled
With garden dirt and barbecue sauce and dried them, and then placed them in
washing machines. Plain water
better than either of the two deter—‘
.
gents. Even taking into acCount that no tests “for greasé (soap or detergents
*
are essential to remove grease) or bacteria Wer—e.made, the experiment illu.e—
_
trated water’s important role in cleaning—à proCess that is usually attributed
_
—
to the cleaning agent alone “[:40]. ,
.
"
»
_…
Ÿ
:
'
w
Cases.
that-become dissolved in water -origirrâte, from twomam :
,
sources: the atmosphere-and the byproducts of the metàbolisms of 1iÿing»ôf—
“
gam'sms. The air contains 78 percent nitrogen, 21
.
—
percent carbon dioxide. The amountof'each ofieségasesjthatwrbefound _
.
in water depends on the relative amount of that “gas in the atmosphere,
,
=
whether or not the gas
reacts With water, and, its sdubiütyboefjciêñï’î“(the
liters of gas absorbed;by one liter of water at 0°C and one
sure). Oxygen and nitrogen have c‘omparatively low solubility coefcients
_
(0.049 for oxygen and 0.024 for nitrogen) and are not found in large amounts
in the water. The solubility coefcient of carbon dioxide, on the other hand, is
1.713. In addition, carbon dioxide reacts with water. Thus, compared to the
small amount of carbon dioxide found in the air, a relatively large proportion
is found in the water. Biological processes
contribute gases
to the water also.
Oxygen is a product of photosynthesis; carbon dioxide is a product of respira—
tion; and hydrogen, methane, ammonia, and hydrogen sulde are all products
of the bacterial decomposition of organic matter.
pH and Carbon Dioxide. The pH of any body of water describes its degree of acidi_ty or alkalinitÿ. The pH scale, which ranges from 0 to 14, mea—
sures the concentration of hydrogen ions (hydrogen atoms with a positive elec—
tric Charge) and hydroxyl ions (an oxygen and a hydrogen atom With a
negative charge). If a. solution has equal numbers of hydrogen and hydroxyl
«on the pH scale, or 7. More hydroxyl ions in—
crease’s,thtæ;àlkalinity, (The: scale is logarithmic, so a pH of 5 isten times more
_
acid than
of 9 is ten times more
pH Off—8.)
_
.
Pure,,diStled?watenhaspaf—pH of 7, and the pH of most naturalwæitersis 7
9 j
7
_
…
f
—
‘