1966 by Swedish scientists. Evidence now shows that PCBs and DDT are
'
globally distributed [31]. It is estimated, for example, that the Great Lakes
[
contain 100 tons of PCBs [32]. The PCBS may be ingested by sh that are
then eaten by humans, or sh containing PCBS may be used for making anjmal feed and the animals fed may, in_turn, be eaten by humans.
}
Some of the toxic effects of PCBS on humans were studied in ]apan after
an epidemic of PCB poisoning from contaminated rice oil occurred there in
Î :
1968 [33]. At last count in 1971, 1057 people were believed to have been af—
[
fected. The disease, called Yusho (oil disease), caused eye discharge and a
swelling of the upper eyelids, fellowed by acne, changes in skin pigmentation,
.
[
and a feeling of weakness and fatigue. Even babies born to mothers who had
]
eaten the contaminated oil showed some of the symptoms, especially dark-_
ening of the skin and nails and increased eye discharge. Three years after the
incident an examination of the patients showed that the condition had im—
proved in some, but had worsened in others.
Since PCBS are widely distributed in the environment, it is now important
Î z '
to know whether like DDT, they can be found in humans. A Human Mon—
itoring Survey of pesticide levels in the US. population initiated in 1967 in—
%
cluded a study of the levels of PCBS in the fat tissue of humans. PCBs are
widespread in the population according to the preliminary data collected
thus far. Of 637 samples analyzed, 31 percent contained at least one ppm of
[
PCBs, 20 percent contained less than one ppm of PCBS, and the remainder
;
were negative. Positive samples were received from every hospital in every
city and state surveyed [34].
Oil.
Oil is another persistent chemical contaminant with profound biological effects. One of the most complicated natural mixtures on earth, petro—
leum contains a wide variety of hydrocarbons, including some that are toxic
and some that are carcinogenic. A year after an oil spill near the Woods Hole
Oceanographic Institute in Massachusetts, some of these hydrocarbons could
_
still be found in the coastal sediments. They became concentrated in the fatty
parts of marine organisms such as bottom invertebrates and can be passed on
up the food chain until they eventually reach man [35]. Oil may also concentrate other fat—soluble poisons present in the water such as insecticides, mak—
ing these pollutants available to marine food chains in higher concentrations
than would otherwise be the case [36].
Chlorine.
As sources of unpolluted water become fewer and as the quan—
tities of sewage dumped into specic waterways increase, disinfection re—
quires ever larger amounts of chlorine. Another factor responsible for increasing the use of chlorine is that some chemical pollutants—ammonia, cyanide,
and various organics, for example—combine with chlorine, reducing its effec—
_
tiveness as a bacteriocide. More and more communities therefore are nding
that their drinking water frequently tastes or smells of chlorine. Chicago,
‘
which has increased its use of chlorine by 67 percent over the past 20 years
-‘_f
(as noted in “Assault on a Lake”) is by no means alone.
160
Drinking Water
_
'
globally distributed [31]. It is estimated, for example, that the Great Lakes
[
contain 100 tons of PCBs [32]. The PCBS may be ingested by sh that are
then eaten by humans, or sh containing PCBS may be used for making anjmal feed and the animals fed may, in_turn, be eaten by humans.
}
Some of the toxic effects of PCBS on humans were studied in ]apan after
an epidemic of PCB poisoning from contaminated rice oil occurred there in
Î :
1968 [33]. At last count in 1971, 1057 people were believed to have been af—
[
fected. The disease, called Yusho (oil disease), caused eye discharge and a
swelling of the upper eyelids, fellowed by acne, changes in skin pigmentation,
.
[
and a feeling of weakness and fatigue. Even babies born to mothers who had
]
eaten the contaminated oil showed some of the symptoms, especially dark-_
ening of the skin and nails and increased eye discharge. Three years after the
incident an examination of the patients showed that the condition had im—
proved in some, but had worsened in others.
Since PCBS are widely distributed in the environment, it is now important
Î z '
to know whether like DDT, they can be found in humans. A Human Mon—
itoring Survey of pesticide levels in the US. population initiated in 1967 in—
%
cluded a study of the levels of PCBS in the fat tissue of humans. PCBs are
widespread in the population according to the preliminary data collected
thus far. Of 637 samples analyzed, 31 percent contained at least one ppm of
[
PCBs, 20 percent contained less than one ppm of PCBS, and the remainder
;
were negative. Positive samples were received from every hospital in every
city and state surveyed [34].
Oil.
Oil is another persistent chemical contaminant with profound biological effects. One of the most complicated natural mixtures on earth, petro—
leum contains a wide variety of hydrocarbons, including some that are toxic
and some that are carcinogenic. A year after an oil spill near the Woods Hole
Oceanographic Institute in Massachusetts, some of these hydrocarbons could
_
still be found in the coastal sediments. They became concentrated in the fatty
parts of marine organisms such as bottom invertebrates and can be passed on
up the food chain until they eventually reach man [35]. Oil may also concentrate other fat—soluble poisons present in the water such as insecticides, mak—
ing these pollutants available to marine food chains in higher concentrations
than would otherwise be the case [36].
Chlorine.
As sources of unpolluted water become fewer and as the quan—
tities of sewage dumped into specic waterways increase, disinfection re—
quires ever larger amounts of chlorine. Another factor responsible for increasing the use of chlorine is that some chemical pollutants—ammonia, cyanide,
and various organics, for example—combine with chlorine, reducing its effec—
_
tiveness as a bacteriocide. More and more communities therefore are nding
that their drinking water frequently tastes or smells of chlorine. Chicago,
‘
which has increased its use of chlorine by 67 percent over the past 20 years
-‘_f
(as noted in “Assault on a Lake”) is by no means alone.
160
Drinking Water
_