conspectus of researchon copper metabolism and requirements

COPPER METABOLISM AND REQUIREMENTS OF MAN 2021
vomiting and diarrhea and, in larger doses,
intravascular hemolysis (75, 865). It has
also been stated ( 685 ) that in India, where
copper sulfate is a frequent mechanism for
suicide, such symptoms are seen when
about 10 mg of cupric ion are ingested.
Yet, Roberts (641), in reviewing cases of
copper sulfate poisoning admitted to a
large city hospital over 7 years, describes
one individual who knowingly consumed
an estimated 20 g of copper sulfate two
to three times weekly over a period of 4
months (total of about 600 g of the crys
tals, or about 1.25 g of anionic copper per
day). Aside from the usual symptoms of
toxicity, there was an associated hemolytic
anemia, possibly the earliest recorded as
due to copper toxicity. There was reason
ably rapid recovery under conventional
procedures of that period. Two possible
explanations for this unusually high degree
of tolerance to copper are that the subject
greatly overestimated his previous intake
of copper sulfate or that he had adapted
to a high copper intake similar to that oc
curring in pigs (767 ).
There are numerous reports of accidental
and suicidal poisoning from oral intake of
copper sulfate in India (111, 118, 120, 288,
813). In one hospital in India, of all cases
of accidental poisoning admitted, copper
sulfate poisoning represented 33.6% of 238
admissions in 1961 (120) and 26.5% of
admissions in a 9-month period during
1969-1970 (112). In cases of acute copper
poisoning, analyses of urine and feces for
copper give exceedingly high values (111).
Under more normal circumstances of
daily living, varied degrees of copper tox
icity have been recorded, as for example:
1) in young infants presumably exposed
via drinking water and cooked foods, to
water derived from all-copper storage and
conduit systems (662, 816); 2) in children
given tablets containing sulfates of copper,
iron and manganese (220) or accidentally
consuming a solution of copper sulfate
(819); 3) in workers imbibing tea made
from water contaminated by corroded
geysers (557, 701); 4) in consumers of
carbonated beverages from post-mix type
of vending machines with defective valves
(356, 450), or from bottles with corroded
pouring spouts (512); 5) in consumers of
alcoholic beverages left in copper-lined
containers (865) or brewed at home in
metal containers (633); 6) in children
given copper sulfate as an emetic (355 ) ;
and 7) in subjects after exchange trans
fusions (50) and hemodialyses (51, 52,
376, 471, 472, 487, 497), due to copper
present in tap-water used, or to coppercontaining
valves and stopcocks used, in
the conduits. Copper can cross dialyzing
membranes, even against a concentration
gradient, and rather small traces of copper
introduced intraveneously are highly toxic.
Frequently, the result is hemolytic anemia.
Hemodialysis has proved to be ineffective
in treating acute copper poisoning, but
this may have been due to a delay of 13
hours in instituting treatment (10). Bremner
(60) reviews the toxicity of copper
and other heavy metals and Cohen (121)
discusses health hazards from industrial
exposure to copper.
At times it may be difficult in young
infants to determine whether a state of
toxicosis is attributable to an early phase
of Wilson's disease or to high levels of
copper in the family drinking water from
copper pipes (816). Ever since the devel
opment of metal conduits for potable
water, man has been exposed to possibili
ties of zinc poisoning from galvanized
pipes, and of copper poisoning from copper
conduits and storage tanks. In certain city
water supplies, copper salts are added to
maintain a concentration of about 0.06
ppm to restrict the growth of algae in the
reservoirs (550). It is also recognized that
soft waters tend to leach copper conduits
more than do hard waters. An impressive
analysis of complexities involved in engi
neering design of copper conduit systems
to reduce the corrosion process itself, and
to minimize the retention time of water in
small-bore tubes, has been presented by
Page (591). Nevertheless, these problems
are more or less controlled by cosmetic
considerations, since water with high cop
per content develops a surface scum due
to formation of insoluble copper com
pounds. It is generally accepted that a
limit of 1 ppm of copper in supplies of
drinking water is safe and acceptable.
Copper represents one of the earliest
additives for enhancement of the appeal of
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