Phone (419) 475-6458
MEDICAL COLLEGE OF OHIO
AT TOLEDO
P. 0. BOX 6190, TOLEDO, OHIO 43614
DEPARTMENT OF PHARMACOLOGY
AND THERAPEUTICS
6 July 1971
William D. Ruckelshaus
Administrator
Environmental Protection Agency
1626 K Street, N.W.
Washington, D. C. 20460
Dear Mr. Ruckelshaus:
Your Mercury Advisory Committee has completed its report.
If we can help further please feel free to call upon us.
Sincerely,
r f
Edward J. Cafruny, M.D., Ph.D.
Chairman, Mercury Advisory
Commi ttee
EJC.m
EPA 540/5-71-003
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REPORT OF THE MERCURY ADVISORY COMMITTEE
OF THE ENVIRONMENTAL PROTECTION AGENCY
TO THE ADMINISTRATOR
Submitted for the
Mercury Advisory Committee
of the Environmental Protection
Agency
/.- . / .
• . „ - ...'•• -; ./
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INTRODUCTION
On receipt of notices of cancellation of registration of
Algimycin 200, Algimycin 300, and Industrial Algimycin MT-4, the
registrant, Great Lakes Biochemical Company, exercised its rights
(under Section 4.c. of the Federal Insecticide, Fungicide, and
Rodenticide Act) to request that an advisory committee review the
cancellation action. A Mercury Advisory Committee was appointed by
William D. Ruckelshaus, Administrator of the Environmental Protection
Agency. The committee reviewed published literature and considered
all relevant factors pertaining to its charge. Members then assembled
in Washington, D. C. on May 3-4, 1971. During these two days, the
committee met with representatives from Great Lakes Biochemical,
expert witnesses, and representatives of various governmental
agencies. On completion of these hearings, the Mercury Advisory
Committee considered all relevant factors and prepared to submit
recommendations to the Administrator of the Environmental Protection
Agency.
The committee's recommendations are contained in this report
which comprises
Section I - Summary
Section II Efficacy of Mercurial Algicides and
Non-mercurial Substitutes
Section III - Risks to Handlers and Swimmers
Section IV - Contribution to Environmental
Pollution and the Need for Control
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Section V - Appendix A - Members of the
Mercury Advisory Committee
Appendix B - Discussants at May 3 and 4
meeting
Appendix C - EPA staff at May 3 and 4
meeting
Appendix D - Special Exhibits
1. List of chemical algicides
2. Letter from Mr. McNew,
Managing Director,of the
Boyce Thompson Institute
for Plant Research, Inc.
3. Letter from Dr. Robert
G. Tardiff, Chief, Toxicology
Division of Water Hygiene
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Section I - Summary
The Mercury Advisory Committee disapproves the use of Algimycin
products which contain mercury. Accordingly, it recommends that the
cancellation of registration of Algimycin 200 and Algimycin 300, July 22,
1969, and Industrial Algimycin MT-4, August 7, 1970 be sustained. As
a basis for this recommendation, the committee cites three major points:
1. Effective substitutes which do not contain mercury
are available.
2. Although algicides containing phenylmercuric com-
pounds have not permanently injured or killed
swimmers or handlers of such compounds, there are
not enough data in the open literature to warrant
the conclusion that mercurial algicides are free
of risk. Granted that any risk involved is
generally of a low order, there are certain groups
(e.g., people with renal disease, others with various
infirmities) who may be especially susceptible to
the deleterious effects of mercurial compounds.
Moreover, the hazards of long-term exposure over
periods of years have not been weighed.
3. Phenylmercuric compounds added to swimming pools
or water cooling towers do not remain confined
at loci of addition. Sooner or later, mercurial
residues are disseminated widely into the soils
and v/aters of the earth. As mercury levels in
the environ.~ant rise, "en end beneficial am>a1s
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must suffer the consequences of mercurial toxicity.
Since it has been clearly shown that free mercuric
ion is released in the tissues of vertebrates
injected with phenylmercurials and that bacteria
can convert inorganic mercury to methyl mercury,
the toxicity of phenyl mercurials in the pharma-
cological sense cannot be separated entirely from
the lesser or greater toxicity of its conversion
products. It is important to note that the
metabolic fate of phenylmercurial compounds
added to swimming pools or water cooling towers
is entirely unknown. The possibility that
bacteria or algae in pools alter the chemical
form of the added mercury has not been excluded.
The Mercury Advisory Committee considers point 3 above to
contain the most cogent and compelling arguments against the use of
mercurial algicides, and sufficient, in itself, to sustain cancella-
tion orders for the registration of Algimycin products.
The committee further recommends that all appropriate agencies
of the Federal. Government mobilize forces so as to mount a concerted,
coordinated campaign against the unnecessary contamination of man's
ecosystem with mercury and its compounds. Tha elimination of mercury-
containing algicides only slightly reduces the environmental burden,
and will have little impact unless all known and potential sources of
mercurv are controlled.
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Section II - Efficacy of Mercurial Algicides
and Non-Mercurial Substitutes
Algal growths in swimming pools are common occurrences in many
private, residential-type swimming pools located outdoors. The
presence of these plankton in swimming pool water is not consistent
with good design and proper operation 'of swimming pools. Algal
growths in swimming pool water are usually indicative of:
1) improper design and/or location of the inlets and
outlets as to provide poor circulation of the water
through the pool;
2) lack of continuous maintenance of a residual amount of
the disinfectant in the swimming pool water so as to
maintain bactericidal conditions in all areas of the
swimming pool at all times;
and/or
3) inadequate maintenance and cleaning of the swimming pool.
The presence of algal growths in swimming pool water is
dependent also upon the presence of sufficient nutrient materials,
particularly phosphates and nitrates, in the water to support the
growth of microscopic plant and animal life. Some community water
supplies have relatively high levels of these nutritive compounds
naturally. Continuous use of swimming pool water over a period of
several months with only a small volume of make-up water added,
usually results in the provision of sufficient nutritive materials
to support algal growths.
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Most algal growths require sunlight or a very high level of
artificial illumination. Most outdoor swimming pools are located so
that all or a major portion of the water surface is exposed to direct
sunlight. Hence, the sunlight requirement for algal growth is
provided.
The most common condition, and the most difficult to correct,
which leads to algal growths in swimming pool water is the failure
to maintain continuously in all areas of the pool a residual level
of the disinfectant sufficient to be bactericidal. Strong sunlight
destroys quickly the residual portion of most disinfectants used in
swimming pool water treatment. Also, most private, residential-type
swimming pools are not equipped with devices to permit continuous
application of the disinfecting chemical. Without such apparatus,
it is impractical, if not impossible, to maintain continuously in
all areas of the swimming pool a residual concentration of the
disinfectant of any detectable amount, much less of a level that is
bactericidal and algicidal or algistatic.
There is, therefore, a practical need to apply an algicidal
chemical to the water of a large number of swimming pools on a regular
basis to prevent the growth of algae. From the public health point
of view, there Is a need to keep swimming pool water relatively free
of algae. Algae interfere with the disinfecting action of the
bactericidal agents used in swimming pool water treatment. Usually,
a greater amount of the bactericide is needed to achieve a satisfactory
level of disinfection. Algae may contribute to accidental injury as
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they may cause the bottom, side-walls, steps, etc. to become slippery.
Also, algae, if present in sufficient numbers, may cause the swimming
pool water to become opaque. This condition may contribute to injury
or drowning by the inability to see someone in the water who may need
assistance. While the presence of algae in swimming pool water is
indicative of poor or inadequate design, operation, and/or maintenance,
practical considerations make it necessary to accept the need for the
routine application of algicides to swimming pool water in many
instances.
There is no question that compounds containing phenylmercuric
acetate are effective algicides in swimming pool v/ater. However, there
are many other compounds that are considered to be equally effective.
For example, many of the quaternary ammonium compounds, if used properly,
are effective in the control of algae in swimming pools.
It is also possible and practicable to use periodic (once every
7-10 days) "super-chlorination" as a means of controlling algae in
swimming pools. The benefit of "super-chlorination" is not limited
to control of algae. "Super-chlorination" is a desirable practice
to inactivate resistant bacteria, viruses, and other microscopic
life and to reduce the concentration of chloro-ammonia compounds in
the swimming pool water. These compounds frequently cause eye
irritation and have reduced efficiency as a bactericide.
In summary, it may be said that for practical reasons, there is
a need for algfcides in swimming pool operation, particularly for
use in many private, residential-type pools. However, there are
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"safe" compounds that may be used to control algae. Similarly,
there is a method of swimming pool operation, namely periodic
super-chlorination, that will control algal growths in swimming pools
under most circumstances. Super-chlorination may be used in conjunc-
tion with other algicides to obtain greater efficiency. It is
acknowledged that compounds containing phenylmercuric acetate, such
as "Algimycin 200" and Algimycin 300", are effective algicides in
the treatment of swimming pool water, but it must be acknowledged
also that phenylmercuric acetate compounds are not superior to other
agents or processes. A number of effective algidical agents is
listed in Appendix Dl. Additional information concerning the effective-
ness of algicides is presented in Appendix D2.
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Section III - Risks to Handlers and Swimmers
There appears to be no clinical or laboratory evidence that
phenylmercuric compounds,when used properly and according to instructions
in swimming pools, constitutes a health hazard to either swimmers or
handlers. An epidemiologic and health status study of workmen exposed
to phenylmercuric compounds for as long as six years has demonstrated
no evidence of adverse health effects except cutaneous reactions which
were not classified. T>2 it is very likely that these were primary
irritant reactions, since the degree of exposure was such that this
type of reaction would be expected. Studies, which cannot be regarded
either as adequate or complete, of swimmers and users of PMA as a
swimming pool algicide have not revealed any adverse health effects.3
However, phenylmercuric compounds when used as weed killers, contra-
ceptive agents, and topical anti-infectives, have been reported to
cause allergic contact dermatitis.4 Among the allergic dermatoses,
cases of cell mediated hypersensitivity of this kind to phenylmercuric
compounds are rare problems. There is also one well documented case
in the literature of allergic asthma and urticaria from phenylmercuric
proprionate in a person with a previous history of atopy.5 It would
appear, then, that both cell mediated and immediate types of hyper-
sensitivity are infrequently provoked but known to occur. Such cases
have not been reported among swimmers in pools using PMA as an algicide
or handlers of PMA used as a slimicidefor industrial cooling systems.
On the other hand, nercurial algicides cannot be considered to
be entirely innocuous. The rubber of s^ir'-ing pools in the United States
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continues to increase yearly. For many people, exposure to waters
treated with mercurial algicides has become a frequent event, repeated
periodically over a period of many years. Dose-effect and time-effect
data are not available. Total intake of mercury must be considered.
There are multiple avenues for intake .(e.g., inhalation, ingestion of
pool waters, absorption through intact or abraded skin). Whatever
amount is absorbed by these routes is simply added to the total body
burden of mercury derived from an already contaminated ecosphere.
Whether this additional exposure to mercurial algicides will prove
to be injurious to various organs and tissues is an unanswerable
question at this time. The question certainly merits attention, for
mercurials are persistent in human tissues and may accumulate to
dangerous levels especially in individuals whose renal function is
impaired.
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Section III - References
1. Goldwater, L. J., Jacobs, M. B., and Ladd, A. C.: Absorption
and Excretion of Mercury in Man. IV. Tolerance to Mercury,
Arch. Environ. Health 7:568-573, 1963.
2. Ladd, A. C., Goldwater, L. J., and Jacobs, M. B.: Absorption
and Excretion of Mercury in Man. V. Toxicity of Phenyl-
mercurials. Arch. Environ. Health 9:43-52, 1964.
3. Wisconsin Alumni Research Foundation: Algimycin 200 in Swimming
Pools, Exhibit 7.
4. Morris, G. E.: Dermatoses from Phenylmercuric Salts. Arch.
Environ. Health 1:53-55, 1960. '
5. Matthews, K. P.: Immediate Type Hypersensitivity to Phenyl-
mercuric Compounds. Am. J. Med. 44:310-318, 1968.
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Section IV - Contribution to Environmental Pollution
and the Need for Control
There is now overwhelming evidence that man has contributed
significantly to the increasing amounts of mercury found in the
environment, particularly in water. foods, and airj In streams
and oceans, the levels reached are such as to render certain fish
inedible, and in some countries undesirable concentrations of mercury
are found in staple foods, such as rice, fruits, eggs, and meat.
Since inorganic mercury may be transformed by anaerobic microbial
systems in the sediments of waterways to methy!mercury, both
discharges of methylmercury as well as inorganic mercury into streams,
estuaries and oceans, contribute significantly to the depot of
methylmercury to the earth's waters. There is convincing evidence
that phenylmercuric compounds may be converted by vertebrate biological
systems to the inorganic form and then by microbial metabolism into
methylmercury. Hence, phenylmercuric compounds which are eventually
discharged from sewer outflows into streams or other bodies of water
probably add to the depot of methylmercury in our waters. At this
point in time it is, therefore, urgent that all controllable sources
of mercury, including phenylmercuric compound uses, be eliminated or
maximally reduced. Mercurial algicide is an identifiable and an
easily eliminated source of contamination. While its use may represent
a minor item in the world's total use of mercury and a small contributor
as compared with the nercury used in chloralkali plants, electrical
equipment, and exterior paints, it is essential that phenylmercuric
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discharges as well as the major contributors to mercury contamination
of the environment be eliminated. It is essential that a coordinated
effort to avoid discharge of mercury compounds into water, air, or
landscape be undertaken. Phenylmercuric acetate may be eliminated
by substituting equally effective compounds which are less toxic for
man and animals. For this cogent reason above, the registration of
PMA as an algicide for swimming pools and slimicide for cooling
systems be cancelled.
If algicides are needed in a swimming pool, it is likely that
chlorination is not - or cannot be - effectively utilized (see
Section II). If chlorination is not effectively used, there is likely
to be a host of bacteria in the pool waters. This is an important
observation in any consideration of the mobility of mercury in the
environment. It is the microbial transformation of inorganic mercury
to methylmercury that so stunned scientists and demanded a new look
into the whole mercury problem. It now appears that all forms of
mercury may be directly or indirectly capable of conversion to methy!-
mercury.2 It has even been stated that certain bacteria appear
capable of converting mercury compounds into metallic mercury vapor.3
Insofar as the phenylmercurials used in swimming pools is concerned,
Jernelov suggests that they are more efficient sources of mercury for
subsequent methylation than is inorganic mercury. ^
In evaluating the mobility of mercury in the environment and its
ecological effects, it is necessary to look at the transforming
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reactions that occur. For phenylmercury, Jernelov4 cites the
fol1owi ng:
(C6H5)2 Hg
II
(CH3)2 Hg
J1
Hg
The above conversion of phenylmercury to mono- and dimethyl -
mercury in bottom sediments has been demonstrated. In this work",
however, Jernelov notes that it has been very difficult to
quantitatively repeat these experiments. This may be a manifesta-
tion of the loss of the more volatile dimethylmercury and perhaps
other volatile intermediate forms. A great deal of the mercury
"cycle" needs yet to be pieced together. We do not know all the
environments in which methyl ation can occur.
Phenylmercury, when used in swimming pools for algae control,
must be repeatedly brought up to strength.5 Quite obviously, mercury
is lost from the pool. Some may be volatilized directly to the
atmosphere. Some will be splashed out onto the ground. In some
locations, swimming pool waters can be discharged directly into a
sanitary sewer system, thence going to the sewage treatment plant.
In other locations it is possible to get a permit to empty a
swimming pool into a storrcwater drainage system. The important
point is that the -swimming pool is not a mercury sink - mercury
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moves from the pool into the environment.
Although it has been stated that phenylmercury is an efficient
form of mercury for subsequent methylation, mercury need not be in
the phenyl form to migrate. Jonasson and Boyle of the Geological Survey
of Canada suggest that mercury can migrate as sulfate, nitrate, various
chloride complexes, carbonate complexes, hydroxide complexes, ammonia
complexes, and as a variety of chelated and other organo metallic
complexes. *>
Although the quantification of the various pathways followed by
mercury in the environment requires much additional study, available
evidence indicates that little, if any, methylation occurs in soils.2
However, Thompson, in. his chapter on Airborne Mercury?, states that
both dimethylmercury and elemental mercury are volatile at ordinary
outdoor temperatures, and that atmospheric variations might be
associated with warming and drying of the soil. Hence, mercury
deposited on land may not methylate directly at that point, but
some will certainly evaporate and be transported to aquatic
environments where methylation can proceed. Thompson cites
unpublished data from Sweden showing the concentrations of mercury
in precipitation, varying from a December low of 0.08ug/l to a July
high of 1.45pg/l.
It is characteristic of mercury that water concentrations are
seldom high. The waters of Minamata Bay - so seriously affected
by pollution - contained only 1.6 to 3.6 ppb. Surveys in the U.S.
show mercury to be generally associated v/ith suspended particles.
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Oceanic mercury is generally present as an anionic complex (HgCl42~)
which does not have so pronounced a tendency to adhere to particu-
lates as do forms of mercury found in fresh waters.3 Even today,
most waters of Sweden need not be monitored.8
Attempts have been made to establish limits or standards for
mercury discharged to aquatic environments. These have revealed that
the mercury compounds tested were quite toxic even at low concentra-
tions, and a level of no effect is difficult to arrive at. For
example, ethylmercury at 60 ppb (parts ethylmercury per billion
parts of water) was found to be lethal to marine phytopiankton, .but
as little alkylmercury as 0.1 - 0.6 ppb measurably reduced photo-
synthesis and growth. In another study, goldfish exposed to mercuric
chloride at 820 ppb died in seven days, but only two days exposure
to 3 ppb impaired their "learning".-* Harriss et. al., after their
studies on phytoplankton, concluded that effects below 1 ppb must
be determined in order to establish adequate water quality standards.^
By comparison, drinking water standards in both the U.S. and the U.S.S.R.
currently recommend a value of 5 ppb.
Swedish studies (Johnels and Westermark) have documented the
increasing mercury content of the biosphere. In this unique work,
the accumulation of mercury in feathers of the goshawk in both
freshly killed birds and in museum collections covering a period of
more than 100 years shows nearly constant mercury levels from the
middle 1800's until 1940. In 1940, alkylnercury seed dressings
were first '.ise'i and tha nrarcury concentration in feathers began an
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upward trend to a level 10 - 20 times that of the constant period.10
Most of the mercury found in animal tissues is methyl mercury.
Other forms of mercury are able to pass into the methyl form in
nature owing to microbial action in bottom sediments. The process
is not well understood and requires far more study to determine
the conditions that permit methyl ation and demethylation and the
rates at which these processes occur. It is evident, however, that
methylation is a common and natural occurrence.8 Jernelov^ states
that if the rate of conversion of inorganic to methylmercury is the
rate-determining step in the removal of mercury from bottom sediments,
it is calculated that this removal would take from 10 to 100 years.
Methylmercury is the form best absorbed and most slowly lost
from animal tissues. It accumulates in the brain where it destroys
cells and causes neurotoxicity. It passes the placenta and damages
the fetus. It accumulates so that repeated minute doses over prolonged
periods can disable. These points are documented for man but apply
more pointedly to animals, because animals living in contaminated
areas are exposed to polluted food such as man only rarely is, and
because some animals excrete mercury more slowly than does man.
Animals that live in polluted water can pick up much mercury directly
from the water - in some instances more than they get from their food.8
The mercury contamination in bottom sediments of waterways
constitutes a depot which, through the methylating process, represents
a continuing source of methyl mercury. All discharges of inorganic
and organic mercury can presumably contribute to this depotJl
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Phenylmercuric compounds used in swimming pools for algae control are
no exception.
That radiation causes genetic damage has been known for many
years and the need for appropriate protection of the American
population has been widely recognized. The principle that exposure
to radiation be kept at the lowest practical level and that there be
no additional exposure unless the harmful effects are outweighed by
anticipated benefits is now well established in the public policy
of this country. The concern is not only for the health and welfare
of contemporary populations but even more important for future •
generations. There is reason to fear that some chemicals and drugs
also may constitute as important a genetic risk, possibly a more
serious one, as radiation. In humans, genetic defects are not
uncommon and are a serious problem. All agents that are introduced
into the environmental microcosm should be seriously considered
and examined for mutagenic effects.
It has been stated on page 567 of "Report of the Secretary's
Commission on Pesticides and Their Relationship to Environmental
Health," Parts 1 and 2, published by the U.S. Department of Health,
Education, and Welfare in December 1969,12 "among the plethora of
new chemicals in our increasingly complex environment, a number
are already known to be mutagenic, i.e., capable of producing
genetic damage. When genetic damage occurs the burden of hereditary
defect in future generations is increased.
One potential- genetic hazard comes from pesticides. Although
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we can point to no pesticide now in wide use that has been demonstrated
to be mutagenic, the overwhelming majority have, however, not-been
adequately tested, although appropriate methodologies are now available.
We define mutations as any inherited alteration in the genetic
material. Such alterations in exposed individuals may lead to cancer
and toteratological effects. Our main concern, however, is for their
descendants; for such changes lead to a wide range of abnormalities,
mental retardation, physical and mental disease, and all the other
inherited weaknesses and debilities to which man is susceptible.
Since these effects will occur in future generations and may be .
apparent only many generations removed, by the time the effect is
noticed, the damage is already irreversible. It is therefore urgent
that any mutagenic chemicals to which the population is exposed be
promptly identified."
In fact, that report went on to recommend that "all currently
used pesticides be tested in the near future... And no new pesticides
should be registered until tested for mutagenicity."
There has been a substantial amount of evidence to indicate
that mercury compounds, including those used as pesticides, also
induce chromosome breaks and mitotic aberrationsJ3 The reasons
for these effects of mercury are not known, except that mercury does
bind to the purines in DNA and this, of course, could change
the genetic message that is synthesized from the DNA template.
On page 39 of the report entitled "Mercury in the Environment:
The Human Element" by Wallace, Fulkerson, Shults and Lyon (ORNL
NSF-EP-1)14, the question of mercury as a nutagen is presented.
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In a section entitled Genetic and Long-term Effects of Mercury
Exposure, it is stated "cytological investigations on plant and animal
cells have shown that mercury compounds give rise to chromosome
breakage and act as inhibitors of the mitotic spindle mechanism, with
the result that polyploidy or abnormal distribution of single
chromosomes occurs. As spindle inhibitors, methyl and phenylmercury
compounds are more potent than any other substance knov/n, including
colchicine. Such preliminary observations would imply that both an
increased genetic load of mutations within living populations and
long-term effects such as carcinogenesis may be influenced by mfircury
in the environment." The report goes on to state that further
investigations should also be undertaken on the various mercury
compounds used in pesticides and Pharmaceuticals.
Organic compounds of mercury have been found experimentally
to produce genetic mutations and chromosomal aberrations in certain
systems of plants and Drosophila.13~16 Such changes, however, have
not been demonstrated in mammals as yet. C-mitosis, defined as
the characteristic appearance of chromosomes which have contracted
more than is usual for mitotic metaphase and lie scattered within
the nucleus, has been demonstrated in cells of Alii urn cepa exposed
to concentrations of phenylmercury compounds at levels as low as
15 x 10-7M (about 0.05 ppm). Some of these compounds also cause
c-mitotic tumors, and hook-like growth of the roots is also observed.
Methylmercury and phenylmercury are among the most active c-mitotic
agents known, being 200-1000 times -ore effective than colchicine.
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In a study with Drosophlla melanogasterl5,16, treatment of
female larvae and adults with phenylmercury acetate resulted in a
significant increase in the number of exceptional daughter offspring
(XXY), showing irregularities of meiotic chromosomal disjunction.
Chromosomal effects and developmental disturbances (mutant gene and
outstretched and bent wing) occurred. There has only been one
report on mammals. These studies with inbred CBA mice failed to
demonstrate dominant lethal mutations after administration of organic
mercurial compoundsJ5 However, although pregnant female CBA mice
that received single doses on day 10 of the gestation period did not
appear to be affected, there was in these animals a high frequency
of resorbed litters and an increased percentage of dead fetuses.
It should be pointed out also that Skerfving et. alJ? showed-a
statistical increase in chromosomal breaks in blood cells of human
consumers of large amounts of fish containing methy!mercury. No
such study is available for phenylmercuric acetate. Methyl mercury
phosphate has been shown to have teratogenic effects in pregnant
mice resulting in a 31.6% incidence of cleft palate.^ It is
obvious that in the case of phenylmercuric acetate there have been
very limited, if any, significant experiments dealing with the
mutagenic and teratogenic effect of this agent with the exception
of the work of Ramel.
It must be kept in mind that phenylmercuric acetate does produce
genetic damage in Alii urn cepa roots and Drosophila and,although
the genetic effects have not been studied to any extent in rar:.:alici
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systems,they may occur. It is also well to keep in mind that when
•
swimming pool water containing phenylmercuric acetate is emptied,
the mercury compound enters the ecosphere, and by simple forms of
life taking it up, mutations are not only possible in these simple
life forms but also in the higher forms of life that eventually
ingest the simpler forms.
Thus because of the known genetic effects of phenylmercuric
acetate in Aliiurn cepa and Drosophila, even though the experiments
are limited in number, a strong possibility exists that this agent
would have harmful genetic effects in humans.
The present problem regarding environmental Hg contamination
has stemmed from a lack of understanding that discharge of this
element in its various forms into ecosystems presented a potential
for unforeseen transformations of a hazardous nature. This was
particularly true of the discharge of the elemental, metallic form,
which had been considered as relatively chemically - and therefore
biologically - inert. The elemental form is known to be under
most conditions inaccessible to biological systems except in its
volatilized or vapor state; therefore being relatively unavailable
to living systems, metallic mercury was considered to be of low
toxicity with the exception noted regarding its vapor.
A parallelism between our consideration of the aryl mercuric
forms of mercury as compared with elemental contamination is
discomforting. That is, once again, the aryl mercury compounds
i
are of relatively-lo1'/ toxicity compared to the alkylmercury compounds.
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Furthermore, whereas the literature is replete with human and animal
toxicity data concerning deleterious effects of alkylmercurials, there
are relatively few reports of similar problem of toxicity due to the
aryl forms - with the exception of some cases with suicidal intent.
Thus there could be a similar tendency, to write off concerns with the
aryl mercurials as a class, if direct human and animal toxicity
were our sole criteria.
It is hoped that the lessons learned regarding elemental mercury's
biotransformation will not be forgotten, especially in view of nature's
almost limitless capabilities for chemical synthesis and transforma-
tion. It would appear that presently available information provides
us with more than a suspicion that the aryl mercurials may be trans-
formed to mono- and dimethyl mercury in experimental systems. Swedish
investigations^ have noted that discharge of phenylmercury appears
to have a more pronounced effect upon mercury build-up in fish than
is the case for discharges of inorganic mercury.
With such a strong suspicion, it would appear prudent to delimit
the discharge of aryl mercurials through relatively uncontrolled use
into the environment. Certainly such discharge increments of the
aryl mercurial slimicidal compounds represents one additional potential
source for methylmercury formation and entry into the food chain.
This would argue for discontinuance of the use of this class of
compound wherein its use is uncontrolled and its discharge considerable
in magnitude.
Such a position should be balanced against the possible harm
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to society of making the compound unavailable. In another portion
of this report the question of appropriate substitutes for the use
in question is considered: it appears that equally effective non-
mercurials are available to achieve the same ends. Accordingly,
the loss to society of Algimycin products would appear to be minimal
compared to the incremental burden these phenylmercurials place
upon the environment.
However, if we are to consider the question in its proper
perspective this discharge of phenylmercuric acetate is a relatively
minor source of environmental contamination. Therefore, for the
proposed action to have any degree of consistency, if the proposed
action stems from a desire to minimize ecosystem mercury burdens,
then other more extensively used phenylmercurials should be similarly
removed from uncontrolled use. Otherwise, the gain to society of
stemming discharge of mercurial algicides from swimming pools would
seem to be minimal.
At this point it is most appropriate to cite the major
recommendations of the special report to the Secretary's Pesticide
Advisory Committee of the Department of HEW of November 1970 on the
Hazards of Mercury:^
"5. . CONTROL.
All controllable sources of mercury contamination
should either be eliminated or maximally reduced.
Thus, (1) the use of all alkylmercury pesticides
should be terminated and all other mercurial pesticides
should be severely restricted to usage on the basis
of demonstrated need only. Safe substitutes should
be soun-'it for those rer:dinihg in use and not now possible
to eliminate.
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(2) Further safeguards should be developed for the
manufacture, packaging, distribution and field use of
seed treated with organic mercurials and for the
disposal of unused treated seed and its containers to
avoid mercurial poisoning through accidents or misuse
of such materials.
(3) All industrial users of mercury, particularly
those operating chlorine and alkali production plants
and those using mercury catalysts, should be required to
reduce their discharges of mercury into the environment
to levels approximating background levels.
(4) Other sources of mercury contamination or
exposure - for example discarded electrical equipment,
chemicals, paints, cosmetics, Pharmaceuticals, sewage,
and fossil fuels - must be identified and brought
under control. The urgency of this is emphasized by
the circumstance that although mercury in any form is •
hazardous, all forms of mercury have the potential to
be converted into the highly toxic form of methyTT
mercury."
The control of mercury contamination from all manmade sources
requires the coordination of efforts by every government agency
empowered to regulate the use and discharge of mercury. In order
to fulfill the recommendations of HEW Committee, it is urgent that
plans be developed collectively by the several national health
agencies responsible for the safety of industrial and consumer
environments - air, water, solid wastes, agricultural uses, forestry
uses, food, drugs, cosmetics, etc. - for the surveillance and control
of the uses and environmental contamination of mercury. In this
planning, it is essential that not only the adverse health effects
on man be considered, but the effects on all forms of life essential
to man's ecosystem. It would appear, then, that effective liaison
for planning and control be developed by the FDA, EPA (for air, v/ater,
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solid wastes, and pesticide regulation), NIOSH and the Department
of Labor, NIEHS, etc. Not until such working liaison is established
will it be possible to reduce the hazards of environmental mercury
to man and his ecosystem.
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Section IV - References
1. Special Report to the Secretary's Pesticide Advisory Committee,
Dept. of HEW, Nov. 1970, Hazards of Mercury. Environ.
Res. 4:1-69, 1971.
2. Shibko, S. I., and Nelson, N.: Microbial transformation of
mercury. Hazards of Mercury, Environmental Research
4(1):23-31, 1971.
3. Wallace, R. A., Fulderson, W., Shults, W. D., and Lyon, W. S.:
Mercury in the environment, the human element. Oak Ridge,
Tenn., January, 1971.
4. Jernelov, A.: Conversion of mercury compounds. Chemical Fallout.
Charles C. Thomas, Pub!., Springfield, 111. (1969), pp. 68-74.
5. See manufacturer's label and recommendations for use.
6. Jonasson, I. R., and Boyle, R. W.: Geochemistry of mercury.
Geological Survey of Canada, Dept. of Energy, Mines and
Resources, Ottawa, Canada (1971).
7. Thompson, J. E.: Airborne mercury. Hazards of Mercury.
Environ. Res. 4(1):50-53, 1971.
8. Stickel, W. H.: -Ecological effects of methyl mercury contamina-
tion. Hazards of Mercury. Environ. Res. 4(1):31-41, 1971.
9. Harriss, R. C., White, D. B., and Macfarlane, R. B.: Mercury
compounds reduce photosynthesis by plankton. Science 170:
736-737, 1970.
10. Johnels, A. G., and Westermark, T.: Mercury contamination of the
environment in Sweden. In Chemical Fallout, Charles C.
Thomas, Pub!., Springfield, 111., pp. 221-239.
11. Nelson, N.: Introduction and Summary of conclusions and recommenda-
tions. Hazards of Mercury. Environ. Res. 4(l):4-9, 1971.
12. Report of the Secretary's Commission on Pesticides and Their
Relationship to Environmental Health, U.S. Department of
Health, Education, and Welfare, 1969.
13. Ramel, C.: Genetic effects of organic mercury compounds. I. Cyto-
logical investigations on allium roots. Hereditas 61:208, 1969
14. Wallace, R. £.; Fulkerson, II., Shults, V!. D., and Lyon, V,1. S.:
Mercury In the Environment: The K'j.^an Eler^nt, OR.'.'L '1SF-EP-1.
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15. Ramel, C.: Genetic effects of organic mercury compounds.
Hereditas 57:445, 1967.
16. Ramel, C., and Magnusson, J.: Genetic effects of organic
mercury compounds. II. Chromosome segregation in
Drosophila melanogaster. Hereditas 61:231, 1969.
17. Skerfving, S., Hansson, K., and L.indsten, J.: Chromosome
breakage in humans exposed to methyl mercury through
fish consumption. Arch. Environ. Health 21:133, 1970.
18. Oharazawa, H.: Effect of ethyl mercuric phosphate in the
pregnant mouse on chromosome abnormalities and fetal
malformation. J. Jap. Obstet. Gynecol. Soc. 29:14, 1968.
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Section V
Appendix A - Members of the Mercury Advisory Committee
Edward J. Cafruny, M. D., Ph. D., Chairman
Professor and Chairman
Department of Pharmacology
and Therapeutics
Medical College of Ohio
P. 0. Box 6190
Toledo, Ohio 43614
H. V. Aposhian, Ph. D.
Professor, Cell Biology and
Pharmacology
Department of Cell Biology
and Pharmacology
University of Maryland
School of Medicine
Baltimore, Maryland 21201
Bertram D. Dinman, M. D., Sc. D.
Director, Institute of
Environmental and Industrial Health
University of Michigan
School of Public Health
Ann Arbor, Michigan 48104
Eric W. Mood, Jr.
Associate Professor of Public Health
and Chief, Environmental Management
and Control Section
Department of Epidemiology and
Public Health
Yale University
School of Medicine
60 College Street
New Haven, Connecticut 06510
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Raymond R. Suskind, M. D.
Director, Kettering Laboratory
Department of Environmental Health
University of Cincinnati Medical Center
Eden and Bethesda Avenues
Cincinnati, Ohio 45219
Harold W. Wolf, Ph. D.
Director
Dallas Water Reclamation Research Center
Dallas, Texas 75216
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Section V
Appendix B - Discussants at May 3 and 4 Meeting
Mr. James F. Stern, Attorney
Executive Vice President,
Great Lakes Biochemical Company
Dr. Robert M. Stern, President
Great Lakes Biochemical Company
Dr. Paul 0. Nees
Wisconsin Alumni Research Foundation
Dr. Leonard J. Goldwater
Dr. George P. Fitzgerald
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Section V
Appendix C - EPA Staff at May 3 and 4 Meeting
Mr. Harold 6. Alford, Acting Director
Pesticides Regulations Division
Mr. David L. Bowen, Secretariat
Pesticides Regulations Division
Mr. Edward Carter
Pesticides Regulations Division
Mr. Robert Caswell
Pesticides Regulations Division
Mr. Joe Cummings
Pesticides Tolerances Division
Dr. Lamar Dale
Pesticides Regulations Division
Mr. Thomas Kemp
OGC
Miss Harriett Lewis, Stenographer
Pesticides Regulations Division
Dr. Thomas McClure
Pesticides Regulations Division
Dr. Ernest Walker
Pesticides Regulations Division
Mr. P. W. Whiteaker
Pesticides Regulations Division
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APPENDIX D1
Chemicals Used for Algae Control in Water Cooling Towers
Quaternary Ammonium Compound
Quaternary + TBTO
Na salt of pent^chlorophenate
K salt of "
Na salt of trichlorophenate
K salt of "
Mixtures of phenates
Sodium ethyl mercury thio salicylate
Potassium permanganate
Copper sulfate chelated
Chlorine as cyanurates
Na hypochlorite
Dehydroabietylamine acetate
Na salt of 0-benzyl-p-chlorophenol + K and Na salts
K salt of
Chlorinedioxide
1,3-dichloro-e,5-dimethy1 hydantoin
Dodecyl guanidine hydrochloride
Methylene bis thiocyanate
Bis trichloro methyl sulfone
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APPENDIX D2
BOYCE THOMPSON INSTITUTE FOR PLANT RESEARCH, Inc. .
IO86 NORTH BROADWAY \V>^
YONKERS. N. Y. 107OJ V^
GEORGE L. McNEW „ _
DIRECTOR May 7, 1971
Dr. Edward J. Cafruny
Dept. of Pharmacology
Medical College of Ohio
Toledo, Ohio £3614-
Dear Dr. Cafruny:
Dr. Susskind asked ;bhat I write you regarding the potential hazard
to the environment from use of phenylmercuric acetate as an algicide for
swimming pools. My experience with this material has been primarily for
use as a seed disinfectant and spray material for eradication of apple
scab (Venturj.a inaequalis) on foliage early in the season before fruit
began to enlarge.
I do know, however, that the material has been used very satis-
factorily under the name of Algimycin for treating swimming pools. If
I recall correctly, a solution of 5% or less is diluted to about .09 ppm.
of water. The material quickly (8 to 12 hours) reduces in concentration
to about 10^ of this level. Presumably this is due to its rapid uptake by
algae or other microorganisms but I assume a minor source of less - and a
very inconsequential one - would be by volatilization. The residual
amounts discharged when the pools are cleaned could go into drainage lines
or into soil. In my opinion it would be quickly bound to organic matter.
The only potential hazard I could visualize would be its conversion to
methyl mercury but it would seem to be of such minor occurrence that it
should not be of substantial hazard.
As you know, there are a number of fungicides that are algicides
which would be free of toxic effects. For many years copper sulfate was
used in ponds for this purpose. I believe Phelps Dodge Co. has a sub-
stantial file on this use. Another prospect would be Dichlone (Phygon of
U. S. Rubber Co.) or 2,3-dichloronaphthoquinone. I know the Maugatuck
Chemical Division of U. S. Rubber Co. made some extensive tests against
algae in Wisconsin lakes when eutrophication set in about 20 years ago.
I do not recc.ll v'.-.o collaborated with then at the University but I suspect
Dean Glenn Pound of the College of Agriculture might recall the individual.
I suspect the copper would cause some ninor irritation in pools and
Dichlone night cause skin irritation since an occasional rare individual
reacts to it. A very logical fungicide would be Captan cut I know of no
tests against algae.
Sir.ceraly yours,
Georga L.- ^Icw
Managing Director
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APPENDIX D3
ENVIRONMENTAL PROTECTION AGENCY
WATER QUALITY OFFICE
5555 Ridge Avenue, Cincinnati, Ohio 45213
May 7, 1971
Mr. David Bowen
Secretariat
Mercury Advisory Committee
Pesticides Regulations Division
Environmental Protection Agency
Room 21kk
South Agricultural Building
12th and Independence, S.W.
Washington, D. C. 2002^
Dear Mr. Bowen:
In the past, the Division of Water Hygiene, V/0.0, EPA, (formerly the
Bureau of Water Hygiene, U.S.P.H.S.) has been asked by other federal
agencies and by some state health agencies to evaluate the toxicity
of phenyl mercuric acetate (PKA) for use in swimming pools and-to
render an opinion as to its acceptability from a public health stand-
point. As the Division's toxicologist, I was assigned these .evalua-
tions. In each case, my professional judgement led me to conclude
that PMA v/as not acceptable from a public health standpoint for use in
swimming pools. The reason for my decision was based on the following:
1. The relatively high acute and subacute toxicity of PMA to
experimental animals;
2. The degree of absorption of PMA via the cutaneous and
gastro-intestinal routes of those individuals swimming in
the PMA treated water, including the likelihood of
Ingesting the pool v/ater while swimming;
3. The addition to the total body burden of mercury from
the absorption of PMA;
k. The possible conversion of PMA to other more toxic forms
of mercury by aerobic bacteria; and
5. Other less toxic algicides were available for use in
swimming pools.
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Page 2 - Mr. David Bowen
Currently, the Drinking Water Standards Committee of the EPA is
proposing a drinking water standard for mercury at 0.005 mg per
liter (ppm). In reconrmending this limit, it is the intention of
the Committee that the standard pertain to unintentionally present
mercurials and that the limit should not constitute a license to
deliberately add mercury to water which is for human use (i.e.,
drinking and bathing).
Sincerely yours,
Robert G. Tardiff, Ph.D.
Chief, Toxicology
Division of Water Hygiene
EPA 540/5-71-003
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