But the problem of the interaction of chlorine and other chemicals is
more serious than the taste or smell of chlorine. The entire range of possible
reactions that might occur between chlorine and other water contaminants
has not been studied. A particular danger, for example, would be the forma—
tion of chlorinated hydrocarbons. Included in the mixture of chemicals found
in the Lower Mississippi survey were biphenyls and a number of benzene
compounds. In the presence of iron, the biphenyls may react to form PCBs.
In the laboratory, it is very easy
to produce gamma—benzenehexachloride by
bringing chlorine and benzene together in the presence of ultraviolet light.
Two of the commercial names for this comp0und are
Gammexane and Lind—
ane, both insecticides. The possibility thattl$insecticide is being produced
in the river should be investigated [37].
;
:
_
The problems resulting from the use of ”chlorine (as well as chlorine’s pos—
sible ineffectiveness in killing viruses, to be discussed later) make it desirable
to find an alternative water purier. The hazard of transporting chlorine is &
further incentive to seek a safe and effective substitute. Five million tons of
chlorine were transported in 1967 [38], and the amount probably continues to
increase. In truck or railroad accidents involving chlorine, the chemical may
'
vaporize and expose people inthe vicinity to highly toxic chlorine gas—one
…
of the rst gases used in warfare—or liquid chlorine accidentay durnped on
land or in water may kill all soil or aquatic life in the vicinity of the accident.
Ozone, which has been used extensively in Europe as a disinfectant, is
now being considered by some sanitary engineers in the United States as a
possible alternative to chlorine. It has been claimedthat ozone is mdre effec—
tive than chlorine in killing viruses and that ozone would eliminate some of
the problems created by chlorine’s reactivity with organic chemicals [39] as
well as some organic substances responsible for objectionable colors, tastes,
and odors in drinking water.
,
-
'
Both chlorine and ozone may be hazardous to workers who manufacture
and handle them. Ozone is explosive in the gas, liquid, and solid states, and
thus presents an addiüOnal hazard. On the other hand, ozone’s explosiveness
would require that it not be transported, but prepared at the site of dis—
infection, thus eliminating any transportation hazard. At present, the cost of
ozone treatment is higher than chlorine—according to one case study, three
times as high [40]. However, since much less chlorine is needed to obtain dis—
infecting poWer, and new production systems for ozone are being designed, it
_
is expected that the costs can be substanüay reduced. There are obviously
many factors to be
comparing their relative safety and effec—«
tiveness, and
respective cost in monetary and environmental terms.
BiologicalHazards
-'
'
—
As mentioned earlier, the Standard used to measure the biological hazard to
'
humans is
not because coliform bacteria are themselves
.
diseaseorganisms,
they are
indicators of
_
‘
diseaSe
bacteria live__ih fecal
matter in human
_
fï
”
‘
‘
more serious than the taste or smell of chlorine. The entire range of possible
reactions that might occur between chlorine and other water contaminants
has not been studied. A particular danger, for example, would be the forma—
tion of chlorinated hydrocarbons. Included in the mixture of chemicals found
in the Lower Mississippi survey were biphenyls and a number of benzene
compounds. In the presence of iron, the biphenyls may react to form PCBs.
In the laboratory, it is very easy
to produce gamma—benzenehexachloride by
bringing chlorine and benzene together in the presence of ultraviolet light.
Two of the commercial names for this comp0und are
Gammexane and Lind—
ane, both insecticides. The possibility thattl$insecticide is being produced
in the river should be investigated [37].
;
:
_
The problems resulting from the use of ”chlorine (as well as chlorine’s pos—
sible ineffectiveness in killing viruses, to be discussed later) make it desirable
to find an alternative water purier. The hazard of transporting chlorine is &
further incentive to seek a safe and effective substitute. Five million tons of
chlorine were transported in 1967 [38], and the amount probably continues to
increase. In truck or railroad accidents involving chlorine, the chemical may
'
vaporize and expose people inthe vicinity to highly toxic chlorine gas—one
…
of the rst gases used in warfare—or liquid chlorine accidentay durnped on
land or in water may kill all soil or aquatic life in the vicinity of the accident.
Ozone, which has been used extensively in Europe as a disinfectant, is
now being considered by some sanitary engineers in the United States as a
possible alternative to chlorine. It has been claimedthat ozone is mdre effec—
tive than chlorine in killing viruses and that ozone would eliminate some of
the problems created by chlorine’s reactivity with organic chemicals [39] as
well as some organic substances responsible for objectionable colors, tastes,
and odors in drinking water.
,
-
'
Both chlorine and ozone may be hazardous to workers who manufacture
and handle them. Ozone is explosive in the gas, liquid, and solid states, and
thus presents an addiüOnal hazard. On the other hand, ozone’s explosiveness
would require that it not be transported, but prepared at the site of dis—
infection, thus eliminating any transportation hazard. At present, the cost of
ozone treatment is higher than chlorine—according to one case study, three
times as high [40]. However, since much less chlorine is needed to obtain dis—
infecting poWer, and new production systems for ozone are being designed, it
_
is expected that the costs can be substanüay reduced. There are obviously
many factors to be
comparing their relative safety and effec—«
tiveness, and
respective cost in monetary and environmental terms.
BiologicalHazards
-'
'
—
As mentioned earlier, the Standard used to measure the biological hazard to
'
humans is
not because coliform bacteria are themselves
.
diseaseorganisms,
they are
indicators of
_
‘
diseaSe
bacteria live__ih fecal
matter in human
_
fï
”
‘
‘