021726
APPENDIX
TO THE
STATEMENT OF BASIS AND PURPOSE
FOR SYNTHETIC ORGANIC CHEMICALS
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C21726
BENZENE
I. INTRODUCTION
Benzene is produced by petroleum refining, coal tar
distillation, coal processing, and coal coking. The United
States production of benzene in 1973 was over 10 billion pounds
(USITC 1975). It is used primarily as a chemical intermediate in
the manufacture of styrener cyclohexare, detergents, end
pesticides.
It was reported that motor gasoline usually contains less
than 5X benzene (Parkinson, 1971); the concentrations of benzene
in the ambient air of gas stations were 0.001 - 0.008 mg/liter.
Benzene is slightly soluble in water (0.8 ppm by weight at
20°C). Four of the 10 water supplies surveyed by the EPA
contained benzene (EPA, 1975 a,e) at levels between 0.1 - 0.3
pg/liter. The highest concentration of benzene reported in
finished water was 10 pg/liter.
II. METABOLISM
Benzene is excreted rapidly. The metabolic products in the
rat of benzene are phenol, hydroquinone, catechol
hydroxyhydroquinone, and phenylmercapturic acid. conjugated
phenols have been reported by Williams (1975). In human
retention studies, Nomiyama and Momiyama (1974) reported 30%
retention in man when exposed to 52 - 62 ppm for 4 h in air;
Hunter and Blair (1972) noted that humans retained 230 mg after
exposure to 80 - 100 M9/liter for 6 h. Benzene metabolism has
been shown to be inhibited by 3-amino-l,2,4-triazole.
III. HEALTH ASPECTS
A. observations in Man
Acute effects. Single exposures to benzene at 20,000 ppm
have proved to be fatal in man. Industrial air concentrations of
benzene have been reported to give rise to nausea, giddiness,
headache, unconsciousness, convulsions, and paralysis (Browning,
1965; Eckardt, 1973).
Chronic effects. The chronic exposure of humans to benzene
has been reported to produce thrombocytopenia, leukopenia,
myelocytic anemia, and leukemia. Despite negative animal
toxicity data, the evidence t-hat benzene is a leukemogen for man
is convincing. The pathoqenesis of leukemia is usually preceded
by many observed effects on the hematopoietic system (Snyder and
Koosis, 1975; Mai lory e_t a 1., 1939; Browning, 1965; Gerarde .
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1960). The NIOSH (1971) recommended the occupational exposure to
benzene at not in excess of 10 ppm determined as a time-weighted
average exposure for up to a 10-h. workday. A recent review on
the health effects of benzene (NAS, 1976} concludes that:
Most cases of severe benzene intoxication have been
reported in workers exposed to rather high concentrations of
benzene under somewhat unhygienic working conditions. It is
probable that all cases reported as "leukemia associated with
benzene exposure" have resulted from exposure to rather high
concentrations of benzene and other chmicals.
It has been suggested in the literature that "benzene-
induced leukemia" may occur only in individuals who are
highly sensitive because of genetic constitution or because
of synergistic action of other chemical or physical
environmental agents. A co-leukemogenic role for benzene
would explain the failure to induce leukemia in benzene-
exposed animals.
The state of the benzene literature makes it very
difficult or impossible to reach a firm conclusion on the
dose-response relationship in chronic exposure of humans to
benzene. The details of the extent of exposures are either
inadequate or absent. Even in cases where some
concentrations of benzene are reported, the stated
concentrations were based on occasional measurements of short
durations. The role of benzene metabolism in its toxicity
and the significance of benzene-induced chromosome
aberrations are currently unclear. It appears that a
metabolite of benzene may be responsible for its myelotoxic
effects.
Based on available literature, it can be concluded that
benzene may be associated with leukemia; therefore, benzene
must be considered as a suspect leukemogen. More definitive
data are required for an accurate assessment of the
myelotoxic, leukemogenic, and chromosome-damaging effects of
benzene.
B. Observations in Other Species
Acute effects. In an acute study, it was shown that rabbits
absorbed benzene through the skin and underwent anesthesia at
35,000 - 45,000 ppm. Benzene inhaled by mice at 60 mg/liter in
air (18,750 ppm) caused lesions on lipoprotein membranes.
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Chronic effects, in a aeries of chronic studies, bilateral
cataracts were found in 50% of the rats exposed to benzene at 50
ppm for 600 h; at 60 - 863 ppm, rats became leukopenic. It has
also been found that. an. inadequate dietary protein intake has
some bearing on the development of benzene toxicity.
Mutageni. city. Some preliminary work suggests that benzene
may induce mutagenie chromosomal alterations. Forni et al.
(1971) have reported an increased incidence of various~kinds of
chromosomal breaks or aberrations in workers occupationally
exposed to benzene. These observations are complicated by the
fact that there were simultaneous exposures to other compounds.
Carcinoqenicity, Although animal experiments have thus far
proved negative^ with respect to the carcinogenic properties of
the compound (Ward et a_l., 1975), there are some indications that
benzene acts as a cocarcinogen in humane (Pobroklotov, 1972,
Smolik et al., 1913},
Teratogen. icit.y. There is no reported evidence of benzene-
induced teratogenicity,
IV. CARCINOGENIC RISK ESTIMATES
On review of the original data froTi the carcinogenicity study
by Ward e_t al (1915 > f it is concluded that the observed increased
occurrence of granuiocytic leukemia in ten2ene-treated animals is
not statistically significant, even when time to response is
incorporated into tire analysis. Therefore, statistical
extrapolation fro
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V. CONCLUSIONS AND RECOMMENDATIONS
The acute effects of benzene cover a wide range of signs and
symptoms. The effects are transitory but may lead to more
lasting chronic effects such as anemia; if exposure is continuous
and great enough, leukemia is a strong possibility for
susceptible members of the population. There are no dose-
response data on animals and the data on humans are inadeguate to
calculate a risk estimate for ben7ene with mathematical models.
In summary, there is no adequate source of data (animal or
human) on which to basa a statistical extrapolation from high to
low exposure. More dara are needed on the mut^genicity and
teratogenicity of benzene. The cocarcinogenic effect of benzene
should be further explored. If data are available on industrial
benzene exposure, then systematic monitoring should be started
with a view to following the population groups at risk.
Before limits for benzene in drinking water can be
established more extensive toxicological data mjst be gathered
and evaluated.
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D
BIS (2-CFT.OR3ETHYL) ETHER
I. INTRODUCTION
1 bis(2-Chloroethyl)ether (dichloroethyl ether) is used as a
soil fumigant; as an insecticide and acaricide; as a solvent for
fats, waxes, greases, and cellulose esters; as a scouring agent
for textiles; in paints, varnishes; and lacquers; as a paint
remover; in dry cleaning; and in the manufacture of medicinals
and Pharmaceuticals (EPA, 1975d).
bis(2-Chloroethyl)ether is moderately persistent and
insoluble in water. It can be formed during chlorination of
water treatment when ethyl ether is present. bisf2-
Chloroethyl)ether has been identified in finished water at 0.5
Mg/liter in Philadelphia and 0.44 pg/liter in New Orleans (EPA,
1975a,c) .
II. METABOLISM
No data are available on the metabolism, absorption, or
excretion of bis(2-Chloroethyl)ether.
III. HEALTH ASPECTS
A. Observations in Man
Shrenk et al. (1933) exposed humans to bis(2-
Chloroethyl)ether and found that a concentration of 550 ppm was
intolerable and caused irritation of the eyes and nasal passages.
Concentrations of 100 ppm and 260 ppm were irritating, but
tolerable; at 35 ppm, there was no irritation, but a nauseous
odor persisted.
B. Observations in Other Species
Acute effects. The oral LD30 has been 9iven as 75 " 15°
mg/kg in rats (Smyth and Carpenter, 1948; Specter, 1956; Hake ana
Rowe, 1963) and 136 mg/kg and 126 mg/kg in mice and rabbits,
respectively (Spector, 1956). The cutaneous LD50 was 410 mg/kg
(Spector, 1956)^and 90 mg/kg (Hake and Rowe, 1963) in rabbits and
0 3 ml/kg in guinea pigs (Smyth and Carpenter, 1948) . Smyth and
Carpenter (1948) reported that the material caused moderate to
severe irritation to rabbits' eyes, cut that apparent healing
occurred within 21 h. They also exposed six rats to 1,000 ppm
for 45 m. Three of the rats died within 14 days. In another
inhalation study in rats (Carpenter et al., 1949), exposure at
250 ppm for 4 h killed some exposed rats. In guinea pigs, 500-
1,000 ppm produced immediate severe eye and nasal irritation, and
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exposure for 1.5-3 h caused respiratory disturbances and deaths
with pulmonary lesions (Shrenk, 1933).
Chronic effects. In chronic studies, rats and guinea pigs
were exposed to bis(2-Chloroethyl)ether at an average of 414
mg/m3 for 2 h/day, 5 days/w, for 93 exposures during 130 days.
No serious injury and only mild physiologic stress were noted
(Hake and Rowe, 1963).
Muta.geni ci t y. No available data.
CarcinoqenicitY. Berenblum (1935) painted a l.OX solution in
acetone on mice for 15 weeks and found no irritation. Van Duuren
et al, (1972) applied bis (2-Chloroethyl)ether in benzene once to
mouse skin as an initiator and then applied phorbol myristate
three times a week for 590 days. The compound did not show
tumor-initiating activity. The same authors reported the
development of sarcomas at two sites of injection out of 30 mice
receiving one 1.0-mg subcutaneous injection of bis(2-
Chloroethyl)ether per week for their life spans. Seventy two
mice were given oral bis(2-Chloroethyl)ether at 100 mg/kg/day
from week 7 - 28 of life. Afterwards, 300 ppm was fed in the
diet until the 'age of 80 weeks. Male mice of two strains and the
females of one strain had an increased incidence of hepatomas
(Innes et al, 1969) . In another study rats were given 50 mg/kg
and 25 mg/kg by intubation three times per week for 18 months and
followed for 6 months. The compound was not carcinogenic (Ulland
et al. , 1973) .
Teratoqenicity. No available data.
IV. CARCINOGENIC RISK ESTIMATES.
bis(2-Chloroethyl)ether has produced dose related hepatomas
when given orally to mice (Innes et al., 1969). The female mice
of one strain did not develop any hepatomas. The available sets
of dose response data were individually considered as described
in the risk section in the chapter on margin of safety. Each set
of dose response data was used to statistically estimate both the
life-time risk and an upper 95J, confidence bound on the life-time
risk at the low dose level. These estimates are of life-time
human risks and have been corrected for species conversion on a
dose per surface area basis. The risk estimates are expressed as
a probability of cancer after a life-time consumption of 1 liter
of water per day containing Q ppb of the compound of interest.
For example a risk of 1X10-* Q implies a life-time probability of
2X10~5 of cancer if 2 liters per day were consumed and the
concentration of the carcinogen was 10 ppt (i.e. Q=10). This
means that at a concentration of 10 ppb during a lifetime of
exposure this compound would be expected to produce one excess
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case of cancer for every 50,000 persons exposed. If the
population of the United States is taken to be 220 million people
this translates into <*,UOO excess lifetime deaths from cancer or
62.8 per year. For bis(2-chloroethyl)ether at a concentration of
1 Mq/liter (Q=1) the estimated risk for both sexes is 8.1X10-7Q.
The upper 95* confidence estimate is 1.2X10-*Q.
V. CONCLUSIONS AND RECOMMENDATIONS
Even though the acute and chronic effects of bis (2-
ch lo roe thy 1) ether have not been fully established it has been
shown to produce dose-related tumors when given orally to mice.
in view of this potential in humans and taking into account
the risk estimates it is suggested that very strict criteria be
applied when limits for bis (2-chloroethyl)ether in drinking water
are established.
The available chronic toxicity data are summarized in Table
VI-H8.
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TABLE VI-A8. Summary of Chronic
Toxicity Data for Bis(2-ChloroethyljEthor
Dosage Levels and Highest Nb-adverse-
Duration Uo. of Animals per effect Level or Lowest Effect
Soecies of Study Group Minimal-effect Level "casured Reference
Rat 130 days ^lU mg/m ~ild physio- Hake & Pov/e,
(Inhalation) io,::c caress l--o3
Mouse SOwks. 0-100 mg/>.g/day 100 mg/kg/day Kepator.as Innes et al.
(oral) 1969
is compound is a suspected animal carcinogen!
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BRUMOBENZENE
I. INTRODUCTION
Bromobenzene (Monobromobenzene) is used as an intermediate in
organic synthesis, and as additive in motor oil and fuels.
During chlorination water treatment, bromobenzene can be formed
in small quantities USEPA, (1975d). It is insoluble in water
(CPC Handbook of Chemistry G Physics, 1970-1971). Bromobenzene
was found in finished water in the lower Mississippi River area
(EPA, 1972) .
II. METABOLISM
Bromobenzene appears to be metabolized in the rat to an
intermediate that can produce tissue damage (Reid, 1973). This
damage is blocked by prior administration of piperonyl butoxide;
thus, the damage may be due to a toxic metabolite. The
metabolite is apparently produced in the liver and transported to
the kidneys by the circulation. Phenobarbital pretreatnent
increases the liver toxicity of bromobenzene, but. has little or
no effect on the kidneys (Reid et aj.., 1571; Sipes et al., 1974).
Bromobenzene may be metabolized to an eooxide (which causes the
liver damage), excreted in the bile, reabsorbed through the
enterohepatic circulation, and metabolized in several steps to P-
bromophenyl mercapturic acid, which is then excreted in the urine
(Reid et al 1971) .
III. HEALTH ASPECTS
A. Observations in Man
Bromobenzene irritates the skin and is a central nervous
system depressant in humans. Nothing is known about its chronic
effects.
B. Observations in Other Species
Acute effects. In an inhalation study in rats, bromobenzene
was administered daily for a H-h period at 3 Mq/m3, without toxic
effects; 20 pg/m^ was t definite-effect dosage in similar tests
(Shamilov, 1970). 1970).
Chronic effects. No available data.
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10
Mutageriicity. Bromobenzene was not mutagenic in the
Salmonella/microsome test (McCann et al, 1975).
Carcinogenicity* There is no evidence that bromobenzene is
carcinogenic in animals and man.
Teratogenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the
carcinogenicity, teratogenicity and long term oral toxicity of
bromobenzene, estimates of the effects of chronic oral exposure
at low levels cannot be made with any confidence. It is
recommended that studies to produce such information be conducted
before limits in drinking water can be established. since
bromobenzene was negative on the Salmonella/microsome
mutagenicity test, there should be less concern than with those
substances which are positive.
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11
CARBON TETRACHI.QRIDE
I. INTRODUCTION
Over 1 billion pounds of carbon tetrachloride
(tetrachloromethane) was produced in the United States in 1973
(USITC, 1975). It is used mostly in the manufacture of
chlorofluoromethanes, but also in grain fumigants, fire
extinguishers, solvents, and cleaning agents.
Carbon tetrachloride is highly persistent and insoluble in
water. Carbon tetrachloride was identified in District of
Columbia drinking water at 5 pg/liter (Schneiman et al., 1974).
The EPA's 80-city survey showed that it was detected in 10
locations in trace amounts, at 3 jjg/liter or less (EPA, 1975a) .
The survey of 10 water utilities showed that it was present in
eight supplies. The Region V survey of 83 water supplies
indicated that carbon tetrachloride is not formed during
chlorination water treatment (EPA, 1975b).
II. METABOLISM
Carbon tetrachloride in rats and humans is rapidly absorbed
and distributed and is excreted primarily through the lungs. The
excretion products are 85% parent compound, 10% carbon dioxide,
and smaller quantities of other products, including chloroform.
In animal studies, chloroform, hexachloroethane, and two
unidentified metabolites were found in rabbits. The mechanism of
metabolism is postulated as a free-radical pathway (Paul and
Rubinstein, 1963; Butler, 1961; Fowler, 1969; Hathway, 197«;
Recknagel, 1967).
Ill, HEALTH ASPECTS
A. Observations in Man
Carbon tetrachloride is readily abosrbed from the
gastrointestinal tract and by inhalation through the lungs. A
fatal dose for children has been reported as low as 3 ml, but
there is great variation in individual susceptibility.
Intestinal absorption is enhanced by fats, oils and alcohol.
(Masoud et al., 1973).
Some persons exposed to carbon tetrachloride will develop
severe liver damage with little or no evidence of renal
envolvement while others will present with renal shutdown and no
hepatic disease. The reasons for this are not known (Eckardt,
1965) .
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12
In another study, carbon disulfide applied topically,
produced a higher incidence of anemia in female than in male
rats, and teratogenic effects were observed (Gut, 1969). When
rats inhaled carbon disulfide at 10 mg/m', abnormalities of
genitourinary and skeletal systems were found. Disturbances of
ossification and blood formation and dystrophic changes in the
liver and kidney were also noted (Bariliak et al.., 1975) .
Mutagenicity. No available data.
Carcinogenicity. No available data.
Teratogenicity. Bariliak et al. (1975) showed that the
inhalation of 10 mg/m' was lethal to embryos before and after
implanation. Carbon disulfide at 2.2 g/m* for 4 h/day proved
embyrotoxic if given to female rats during gestation and had no
effect on male rats (Sal'nikova and Chirkova, 1974). Inhalation
of lower concentrations (0.34 mg/liter for 210 days caused
disturbances of estrus (Rozewiski et al., 1973). In a dominant-
lethal test, inhalation of 10 mg/m^ by male rats before
copulation proved lethal to embryos (Bariliak et al., 1375) .
IV. CONCLUSIONS AND RECOMMENDATIONS
Carbon disulfide has been demonstrated to produce
distrubances in reproduction as well as teratogenic effects in
animals when inhaled* There is no data availale on
teratogenicity following oral exposure.
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity and lona term oral toxicity of
carbon disulfide, estimates of the effects of chronic oral
exposure at low levels cannot be made with any confidence. It is
recommended that studies to produce such information be conducted
before limits in drinking water can be established.
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1
In eight instances of either acute or subacute carbon
tetrachlpride poisoning seven patients suffered renal
insufficiency and six of these required dialysis. Two died from
heart failure. None of the six survivors showed any evidence of
liver damage (Dume et al., 1969).
Following a large acute exposure the primary finding is of
centrilobular necrosis. If exposure is not too massive repair
may begin after 3 or U days and be complete in three weeks.
Chronic exposure usually results chiefly in symptoms of
gastrointestinal upset such as nausea and vomiting, and nervous
system symptoms such as headache, drowsiness, and excessive
fatigue. It is rare to find jaundice following either acute or
chronic exposure (Browning, 1961).
Gastric symptoms have been reported following chronic
inhalation of from 45 - 100 ppm carbon tetrachlorido. When
exposure is from 100 - 300 ppm the symptoms in addition to
gastrointestinal upset include apathy or mental confusion and
weight loss (Lewis, 1961).
B. Observations in other Species
Acute effects. Oral LD50 values are 6.4 (5.4-7.6) ml/kg in
young male Wistar rats (McLean and McLean, 1966) 4.73 (4.16-5.38)
ml/kg in mature male Sprague-Dawley rats (Pound et al., 1973) and
1.5 ml/kg in male and female mongrel dogs (Klaassen and Plaa,
1967). The intraperitoneal LD50 is 2.23 ml/kg in rats (Maling et
al., 1974). Toxicity indexes have been set up for both animals
and man. Signs and symptoms of toxicity include dyspnea,
cyanosis, proteinuria, hematuria, jaundice, hepatomegaly, optic
neuritis, ventricular fibrillation, eye-nose-throat irritation,
headache, dizziness, nausea, vomiting, abdominal cramps, and
diarrhea.
Chronic effects. Biochemical and biologic lesions include
hepatic cirrhosis and necrosis, renal damage, changes in blood
enzymes (serum glutamic pyruvic transaminase and alkaline
phosphatase), and increased serum bilirubin (Busuttil et al.,
1972, Litchfield and Gartland, 1974).
A variety of interactions have been described to relate
carbon tetrachloride exposure to metabolic inhibitors and
inducers and diet. Many studies have reported reduction or
potentiation of toxicity indexes, including liver necrosis-
cirrhosis and blood enzyme changes (McLean and McLean, 1966;
Maling et al., 1974; Barawill and Gornall, 1952; Cawthorne et
al., 1970 Traiger and Plaa, 1971; Litterst et al., 1973).
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Mutagenicity. Carbon tetrachloride was negative in a host-
mediated assay using NMFI mice and strains GU6 and TA1950 of
Salmonella typhimurium his (Braun and Schoneich, 1975). Carbon
tetrachloride was also negative in an in vitro
Salmonella/microsome mutagenicity assay (McCann et aj.. , 1975) .
Carcinogenicity. In a series of studies of the carcinogenic
potential of carbon tetrachloride, hepatomas were found in mice,
hamsters, and rats after administration hy several routes,
including oral. There was, however, no evidence of tumors in
other organs within the time limits of the experiment (usually
less than life span). The tumor response depended on both the
dosage and the interval between doses. With intermittent
exposure, it was found that total dose and duration were more
important than the dosage (IARC, 1972; Murphy, 1975).
In a sttidy with mice, oral administration of 0.1 ml twice a
week for 20-26 weeks produced hepatomas that were interpreted by
the investigators as indicative of focal nodular hyperplasia, not
neoplasia (Confer and Stenger, 1965). Kawasaki (1965) reported
that 0.2 - 0.3 ml/100 g injected subcutaneously every 2 weeks
produced a low number of hepatomas in Wistar rats. A 1.3 ml/kg
oral dose twice a week for 12 weeks in Buffalo rats was reported
to cause cholangiofibrosis from proliferating' bile ducts (Puber
and Glover, 1967). Oral administration to Syrian golden hamsters
at 6.25 - 12.5 |jl once a week for 30 weeks followed by 25
additional weeks of observation induced liver cell carcinomas
associated with postnecrotic cirrhosis and regenerative
hyperplastic nodules (Della-Porta et al., 1961).
Teratogenicity. No teratogenic effects were seen when
carbontetrachloride was administered to rats (Wilson, 1954).
IV. CARCINOGENIC RISK ESTIMATE
Carbon tetrachloride has been given orally in a number of
studies with mice, rats, hamsters, and dogs (IARC, 1972). It has
also been used as a positive control in cancer tioassays (NCI,
1976). In the trichloroethylene study, the carbon tetrachloride
positive ccntrol produced much higher incidences of
hepatocellular carcinomas than did trichloroethylene.
The available sets of dose response data from the NCI
trichloroethylene bioassay were individually considered as
described in the risk section in the chapter on margin of safety.
Each set of dose response data was used to statistically estimate
both the life-time risk and an upper 95% confidence bound on the
life-time risk at the low dose level. These estimates are of
life-time human risks and have been corrected for species
conversion en a dose per surface area basis. The risk estimates
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are expressed as a probability of cancer after a life-time
consumption of 1 liter of water per day containing Q ppb of the
compound of interest. For example, a risk of 1X10~*Q implies a
life-time probability of 2X10~S of cancer if 2 liters per day
were consumed and the concentration of the carcinogen was 10 ppb
(i.e. Q=10). This means that at a concentration of 10 ppb during
a lifetime of exposure this compound would be expected to produce
one excess case of cancer for every 50,000 persons exposed. If
the population of the United States is taken to be 220 million
people this translates into 4,400 excess lifetime deaths from
cancer or 62.8 per year. Since several data sets are typically
available the range of the low dose risk estimates are reported.
For carbon tetrachloride at a concentration of 1 pg/liter (Q=1)
the projected risk for man would fall between 4.5-5.4XlO-8Q. The
upper 95% confidence estimate of risk at the same concentration
would be from 1.1 - 1.8X10~7 Q.
V. CONCLUSIONS AND RECOMMENDATIONS
The acute-toxicity effects of carbon tetrachloride are best
characterized as hepatic nodular hyperplasia and cirrhosis and
renal dysfunction in both experimental animals and man. It had
no mutagenic potential in in vitro and in vivo test systems. Its
teratogenic potential has not been firmly established.
Carcinogenic bioassays have produced hepatomas in mice, rats, and
hamsters, associated in most cases with regenerative nodular
hyperplasia or postnecrotic cirrhosis.
In light of the above and taking into account the risk
projections it is suggested that very strict criteria be applied
when limits for carbon tetrachloride in drinking water are
established. The available chronic toxicity data are summarized
in Table VI-47.
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TABLE VI-47. Summary of Chronic
Toxicity Data for Carbon Tetrachloride
Species
Mouse
Rat
Rat
(Male)
Rat .
(Female)
Haoster
Duration
of Study
20-26 wks.
12 wks.
78 wks.
78 wks.
30 wks.
Dosage Levels and
No. of Animals per
Group
50 animals/group
0,80,150 rag/kg/day
1*9 animals/group
6. 25 -12. 5 p H week
20 animals
Highest No-adverse-
effect level or lowest
Minimal -effect level
0.1 ml, twice a week
(oral)
1.3 ml/kg twice a week
(oral)
1*7 ing/kg/day
(oral)
80 rag/kg/day
(oral)
6.25 pi/week
(oral)
Effect
Measured
Nodular hyper-
plasia
Cholangio-
fibrosis
Hepatomas
Hepatomas
Hepatomas
Reference
Confer &
Stenger, 1965
Ruber &
Glover, IJc?
NCI, 1976
NCI, 1976
Deila-Porta
et al. , 1961
f Ihi8 compound is an animal carcinogen*]
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TRICHLOROBENZ EWE
I. INTRODUCTION
Trichlorobenzene is produced by chlorination of
monochlorobenzene. It is used as a solvent, dielectric fluid,
lubricant, and heat-transfer medium; in polyester dyeing, and in
termite preparations (EPA, 1975d) .
- *
The United States production of 1,2,4-trichlorobenzene in
1973 was over 28 million pounds (USITC, 1975). it is insoluble
in water (CRC Handbook of Chemistry and Physics, 1970-1971) .
Trichlorobenzene can be formed in small quantities during
chlorination of drinking water (EPA, 1975d) . of the 10 water
supplies surveyed by the EPA (1975a) , trichlorobenzene was only
detected in the finished water of Lawrence, Massachusetts.
II. METABOLISM
In metabolic studies with rabbits using each of the three
isomeric trichlorobenzenes at 0.5 g/kg, 1,2,3-trichlorobenzene
was the most rapidly metabolized, and 1,3,5-trichlorobenzene was
least rapidly metabolized. In 5 days, 62* of the 1,2,3-trichloro
isomer underwent glucuronic conjugation. The major metabolite
was 2,3,U-trichlorophenol; small amounts of 3,«*,5-
trichlorophenol, 3,U,5-trichlorocatechol, and mercapturic acid
were also detected. 1,3,5-Trichlorobenzene formed practically no
ethereal sulfate or mercapturic acid, and the only phenol formed
was 2,4,6-trichlorophenol (Jondorf et al. , 1955).
Along with tests on other halogenated benzenes, 1,3,5-
trichlorobenzene was administered orally to rats at 2 mg/kg, and
this chemical was found in the fat at greater concentrations than
in liver, kidneys, heart, or blood. These studies were designed
to show the possible effects of chlorinated substances from Rhine
River water and how they might affect body burden in animal
tissues and organs (Jacobs et al., 1974) .
III. HEALTH ASPECTS
A. Observations In Man
In one plant where benzene was chlorinated over a period of 1
years, there was no apparent serious illness, liver function
change, or alteration in blood components. One worker who
inhaled a massive amount of trichlorobenzene experienced some
hemorrhaging in the lungs (Erlicher, 1968).
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u
B. Observation In Other Species
Acute effects. Acute-toxicity tests have been conducted in
rats (CFE strain) and mice (CF No. 1 strain) by oral and
percutaneous administration. The single-dose acute oral LD50 was
756 mg/kg in rats. The main signs of intoxication were decrease
in activity at a low dose and convulsions at higher doses. Death
.occurred 5 days after exposure. The single-dose acute oral LD50
was 766 mg/kg in mice. Signs of intoxication were the same as in
rats (Brown et al., 1969).
Chronic effects. In chronic-skin-irritation studies with
rabbits and guinea pigs, trichlorobenzene was not irritating,
although some degreasing action took place after prolonged
contact. After 3 weeks of exposure, there was some skin
inflammation characterized by spongiosis and parakeratosis.
Livers of guinea pigs were found to have necrotic foci (Brown et
al.» 1969). Trichlorobenzene was also evaluated for its
acnegenic potential in rabbits by applying 1,2,a-trichlorobenzene
to the ears of rabbits for 13 weeks. There was no typical
acneiform dermatitits, but there was some dermal irritation
(Powers et al., 1975) .
Mutagenicity. No available data.
CarcinoqenicitY- No available data.
Teratogenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity and long term oral toxicity of
trichlorobenzene, esimates of the effects of chonic oral exposure
at low levels cannot be made with any confidence. It is
recommended that studies to produce such information be conducted
before limits in drinking water can fce established.
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CHLOROBENZENE
I. INTRODUCTION
Chlorobenzene (Monochlorobenzene) is used in the manufacture
of aniline, insecticides, phenol, and chloronitrobenzene and as
an intermediate in the manufacture of dyestuffs (EPA, 1975d).
The United States production of Chlorobenzene in 1973 was over
397 million pounds (OSITC, 1975). During chlorination water
treatment, Chlorobenzene may be formed. It is insoluble in water
(CRC Handbook of Chemistry and Physics, 1970-1971) . Finished
water in nine of the 10 water supplies surveyed by the EPA
(1975a) contained Chlorobenzene, with 5.6 jjg/liter in Terrebonne
Parrish, Louisianna, and 4.7 yg/liter in New York City.
II. METABOLISM
Although many foreign chemicals are metabolized to inactive
substances, Chlorobenzene appears to be converted to a metabolite
that can produce tissue damage. This damage may be blocked by
prior administration of piperonyl butoxide. The metabolite is
apparently produced in the liver and transported to the kidneys
by the circulation. Pretreatment of rats with phenobarbital
increases the liver toxicity of Chlorobenzene (Rei<3, 1973) .
Chlorobenzene may be metabolized to S-(p_-chlorophenyl) mercapturic
acid by several steps (Norton, 1975). The hepatotoxic metabolite
may be an epoxide excreted in the bile, reafcsorbed, and finally
excreted by the kidneys.
III. HEALTH ASPECTS
A. Observations In Man
Chlorobenzene is irritating to the respiratory system and is
a central nervous system depressant. The Union of Soviet
Socialist Republics has suggested 0.02 mg/liter as the maximal
permissible concentration in drinking water (Stoefen, 1973) .
This was based on odor and taste.
B. Observations In Other Species
Acute effects. Chlorobenzene has an acute oral LD50 of 2,910
rog/kg in rats (Toxic Substances List, 1974).
Chronic effects. The no-effect dosage in rats after 7 months
of administration was 0.001 mg/kg/day (Varshavskaya, 1968).
Other studies have shown no-effect oral dosages of 54.5 mg/kg in
dogs and 12.5 mg/kg in rats (Knapp et al., 1971) .
Mutagenicity. No available data.
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Carcinoqenicity. No available data.
Teratogenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity, and long term oral toxic ity of
chlorobenzene, estimates of the effects of chronic oral exposure
at low levels cannot be made with any confidence. It is
recommended that studies to produce such information be conducted
before limits in drinking water can be established.
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PENTACHLOROPHENOL
I. INTRODUCTION
Pentachlorophenol (PCP) has been used since 1936 for wood
preservation (Spencer, 1973) . Domestic production of PCP is
estimated at 46 million pounds a year (National Academy of
Sciences, 1975) .
FTP is produced commercially by the chlorination of phenol
(Spen-'er, .1973) . Commercial-tirade PCP contains 88.1% PCP, 1.1%
tetraohlorophenol, 6.2% higher chlorinated phenoxyphenols,. less
than 0.1% trichlorophenol, and various dibenzo-g-dioxins and
diben -of urans (Johnson et al. f 1973; Schwetz et al. t 1974). The
highly toxic tetrachlorodioxins are not found in technical PCP.
PCP i > soluble in water at 20 ppin at 30°C. It is not very
volatile, as evidenced by a vepor pressure of 1.1 x 10-* mm Hg at
20°C (Spencer, 1973). Concentrations of 0.70 and 0.06 ppb PCP
have !>een observed in river and treated drinking water,
respectively (Ruhler et al. , 1973) . The highest concentration of
PCP reported in United states drinking water was 1.1 ppb (EPA,
II MiTAHOLISM
A pharmacokinetic profile of pentachlorophenol in monkeys and
an elimination study with [ »*c]pentachlorophenol and its
metabolites in rats have been conducted (submitted for
publication in Toxicol. Appl. Pharmacol.). These studies showed
that 90% of a 10 mg/kg dose of PCP in rats is eliminated rapidly
with a half life of from 13 - 17 h depending on sex. PCP is
excreted either as tetrachlorohydroguinone (16%) or as a PCP
glucuron'.de conjugate in the xrrine (9%) or a free PCP (75%). The
excrttio.i pattern in monkeys v;as slower than in rats and almost
all TCP v?as excreted unchanged in urine. It was suggested that
the monkey may be a better animal model and more closely
approximate human pharmacokinetics.
III. HEALTH ASPECTS
f. observations In Man
l-'enon (iy£P) reported loss of appetite, respiratory
difficulties, anesthesia, hyperpyrexia, sweating, dyspnea, and
progressive coma in humans exposed to PCP.
A. number of cases of human poisoning by PCP are reviewed by
Armstronq et aj.. (1969) . The minimum lethal dose for humans is
to be 29 mg/kg (The Toxic Substances List, 1971). Work
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done in Russia has established a maximum permissible
concentration of 40 ng/m3 PCP in the air (Tabakova, 1969).
B. Observations In Other Species
kcui6. effects. The acute, oral LD50s for PCP are: 120-110
mg/kg for the mouse, 27-100 mg/kg for the rat, 100 mg/kg for the
guinea pig, 100 - 130 mg/kg for the rabbit, and 150 - 200 mg/kg
for the dog (Christensen et al. , 197U; Deichmann et al., 19U2;
Knudsen et al., 1974; McGavack et al., 1911; stohlman, 1951. The
acute symptoms of intoxication are vomiting, hyperpyrexia,
elevated blood pressure, increased respiration rate, and
tachycardia. The LD5O after oral administration of PCP to male
and female rats was 146 and 175 mg/kg and upon percutaneous
exposure 320 and 330 mg/kg, respectively (Gaines, 1969).
Subchronic and chronic effects. In a study to determine the
subchronic toxicity of the compound, FCP was fed in the diet to
groups of Wistar rats at concentrations of 0, 25, 50, and 200 ppm
for a 90-day period (Knudsen et al., 1S74). Female rats
receiving 200 ppm (10 mg/kg/day) PCP showed a reduced growth rate
while liver weights were increased in male rats ingesting 200 and
50 ppm (2.5 mg/kg/day). After 6 weeks, rats fed 50 and 200 ppm
PCP showed elevated hemoglobin and hematocrit values whereas at
11 weeks, hemoglobin and erythrocytes were significantly reduced
in the same groups of animals. No PCP related effects were seen
in animals fed 25 ppm (1.25 mg/kg/day). In another experiment,
male rats received 1,000 ppm (50 mg/kg/day) of technical or pure
PCP for a 90-day period (Kimbrough and Linder, 1975). Both PCP
samples caused an increase in liver weight. Much more severe
histopathological changes occurred in the livers of rats given
the technical PCP than in those given the pure PCP. In another
90 day study, Sprague-Dawley rats showed increased liver and
kidney weights, elevated serum alkaline phosphatase, and
depressed serum albumin levels in animals consuming 3 mg/kg/day
of technical PCP (Johnson et al., 1973). when a sample of
improved PCP containing substantially reduced amounts of dioxins
was fed to rats, no adverse effects were seen at 3 mg/kg/day. In
animals receiving chemically cure PCP, kidney and liver weights
were elevated at 30 and 10 mg/kg/day, respectively, but 3
mg/kg/day was without adverse toxicologic effect.
In a chronic study, liver weights were significantly
increased in rats ingesting 500 ppm (25 mg/kg/day) technical PCP
over an 8 month period (Kimbrough and Linder, 1975). No toxic
effects were observed at 100 ppm (5.0 mg/kg/day) PCP.
When female weanling rats were fed pure or technical PCP for
8 months, increased urinary porphyrin excretion and increased
liver porphyrin levels were observed in animals fed 100 (5.0
-------
2.
mg/kg/day) or 500 ppm of the technical product (Goldstein et al.,
1976) . None of the rats fed pure PCP became porphyric. Liver
weights were increased in rats receiving 500 ppm (25 mg/kg/day)
of technical PCP but were unchanged in animals fed 500 ppm of the
pure phenol. Thus the porphyrin and other major liver changes
induced by technical PCP are apparently due to contaminants,
probably the chlorinated dibenzo-p-dioxins, rather than PCP.
Mutagenicity. PCP proved negative in the sex-linked level
test in Drosophila (Vogel and Chandler, 1974).
Carcinogenicity. No available data.
Teratogenicity. In a study to examine the potential
teratogenicity of PCP, purified and commercial grade PCP were
administered to Sprague-Dawley rats on days 6 - 15, 3 - 11, and
12 - 15 of gestation (Schwetz et al., 197U). PCP was embryotoxic
and fetotoxic at doses of the commercial and pure phenol of 15
mg/kg and above. The no adverse effect dose level was 5 mg/kg
for the commercial PCP, but at this same dose level, delayed
ossification of the skull was observed after treatment with pure
PCP.
Oral administration of 0, 1.25, 2.5, 5, 10, and 20 mg/kg PCP
to hamsters on days 5 - 10 of gestation produced fetal death
and/or resorptions at 5 mg/kg/day and above (Hinkle, 1973).
III. CONCLUSIONS AND RECOMMENDATIONS
There are substantial disagreements in the results of several
of the subacute and chronic tcxicity experiments with PCP (Table
1) , perhaps because of the use of inadeguately characterized PCP
preparations in these studies. In addition, two year chronic
toxicity experiments in one or more species have not yet been
conducted with this extensively used chemical. High doses (>5
mg/kg/day) of PCP have been shown to be teratogenic in rats and
hamsters when administered during susceptible days of gestation.
There is also a need for an adequate determination of the
carcinogenic potential of this chemical.
On the basis of the available chronic toxicity data an ADI
for pentachlorophenol has been calculated to be 0.003 mg/kg/day.
The data and calculations are summarized in Table VI-55.
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2,4-DICHLOROPHENOL
I. INTRODUCTION
2,4-Dic ilotophenol is used mainly in organic synthesis. In
the aquatic en\ironment 2,4-D (2,4-dichlorophenoxyacetic acid) is
decomposed to ,;,4-dichlorophenol by sunlight and then to simpler
compounds. 2,t-Dichlorophenol is slightly soluble in water (CRC
Handbook of ch-.-mistry and Physics, 1970-1971) and the highest
cor.centrati n detected in United Statfs drinking watrr was 36
pg/liter (IA, I975a).
II. METABO1 SM
2,U-DiciilO!:oph<'nol is excreted as a conjugate of qlucuronic
acid. Up to M'.% ray be excreted as sulfate in the urine of
rabbits.
Ill. HEALTH AS,ECTS
A. Observations In Man
No studies have been conducted to determine the effects of
2,4-dichlorophenol in man.
B. Observations In Other Species
Acute effects. The effects of an acute oral dose of 2,4-
dichlorophenol have been examined in a variety of experimental
animals; the oral LDSO is 1-63 g/kg in mice and ft.5 g/kg in male
rats (Kobayaski et al., 1972). On acute, subcutaneous
administration, the LDSo was 1,73 g/kg in rats (Deichman, 19U3).
The intraperitoneal LD9O was U20 mg/kg in rats fFarquharson, e_t
al., 1958).
Chronic effects. In a study of the chronic effects of 2,U-
dichlorophenol, it was found that the maximum dose producing no-
observed-adverse-effect mice was 100 mg/kg/day {Kobayaski et al.,
1972). Kongiel-Chablo (1968) found that the administration of
0.2 - 2,000 mg/liter in the drinking water produced no effects,
either on cholinesterase or on serum glutamic oxaloacetic
transmainase in rats.
Mutaqenicity. No available data.
Carcinoqenicity. Boutwell and Bosch (1959) found that the
topical application of 0.3% dimethylbenzanthracene in benzene as
an initiator and 20% (312 mg/kg) 2,1-dichlorophenol for 39 weeks
promoted papillomas and carcinomas in mice.
-------
B. Observations In other Species
Acute effects. The acute oral LD50 of 1,2-dichloroethane has
been established at 0.77 (0.67-0.89) ml/kg in rats (Smyth et al.,
1969). LCso values for vapor inhalation are 12,000 ppm in 0.53
h, 3,000 ppm in 2.75 h, and 1,000 ppm in 7.20 h in rats (Spencer
et al., 1951). In one study with rabbits, the LD50 for skin
penetration was determined to be 3.89 (3.40-54.46) ml/kg. The
toxic effects of single acute exposures to 1,2-dichloroethane
were central nervous system depression, lung irritation, and
injury to the liver, kidneys, and adrenals (Gohlke and Schmidt,
1972).
Chronic effects. When animals were exposed to 1,2-
dichloroethane vapor for 7 h/day, 5/days/week, for 6 months, the
maximal concentrations that produced no adverse effect were 400
ppm in rabbits, 200 ppm in rats, and 100 ppm in monkeys and
guinea pigs (Heppel et a_l., 1946; Yllner, 1971). significant
chronic changes at higher concentrations included hepatic and
renal damage. In other chronic studies, 500 ppm was not
tolerated by rats, guinea pigs, or rabbits, and sianificant
mortality occurred in the first 2 weeks; more than 90£ of the
animals were dead by the end of the fourth week. All the animals
tolerated 100 ppm for a 17-week period (Yllner et al. , 1971;
Hofman et al., 1971).
Mutagenicity. Brem et al., (1974) have reported a mutagenic
effect of 1,2-dichloroethane in S^ typhimurium and DNA
polymerase-deficient E.. coli. It was the weakest, however, of
the series of haloalkanes tested.
Carcinogenicity. No available data.
Teratogenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
.1,2-Dichloroethane has been shown to be weakly mutagenic in
two different mutagenicity screening-tests. There is no data
available on its potential carcinogenicity.
In view of the relative paucity of data on teratogenicity,
carcinogenicity, and long term oral toxicity of 1,2-
dichloroethane, estimates of the effects of chronic oral exposure
at low levels cannot be made with any confidence. It is
recommended that studies to produce such information be conducted
before final limits in drinking water can be established.
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1,2-DICH10ROETHANE
Iw INTRODUCTION
1,2-Dichloroethane (ethylene dichloride) is used in the
manufacture of vinyl chloride and tetraethyl lead; as an
insecticidal fumigant; in -tobacco flavoring; as a constituent of
paint, varnish, and finish removers; as a metal degreaser; in
soap and scouring compounds; in wetting and penetrating agents;
and in chemical synthesis and ore flotation (EPA, 1975d). The
United States production was over 9 billion pounds in 1973
(OSITC, 1975).
1,2-Dichloroethane is difficult to degrade biologically. It
is soluble in about 120 parts of water (Merck Index, 1968). The
Region V survey of 83 water supplies concluded that it is not
produced during chlorination of water. The survey also indicated
that 13% of the finished water contained 1,2-dichloroethane, at a
mean concentration of 1 pg/liter (EPA, 1975b). Of the 80 water
supplies surveyed in 197H, 26 contained 1,2-dichloroethane, at
less than 0.2 to 6 »ig/liter (EPA, 1975a) . A concentration of 8
lig/liter has been reported in New Orleans finished water (EPA,
1974) .
II. METABOLISM
1,2-Dichloroe thane is rapidly absorbed after oral or
pulmonary exposure (Morgan et al., 1970). It is metabolized in
mice by enzymatic dehalogenation and oxidation through the 2-
chloroethanol intermediate to the chloroacetic acid excretion
product (Yllner, 1971). Both enzymatic dehalogenation and
oxidation appear to take place in the liver (Morgan et al.,
1970). The principle target organs in mice are the liver,
kidneys, and adrenals (Plaa and Larson, 1965).
III. HEALTH ASPECTS
A. Observations In Man
In man, exposure to high vapor concentrations of 1,2-
dichlorotthane results in irritation of the eyes, nose, and
throat. Continued or repeated exposure to concentrations above
the response threshold produce central nervous system depression
and injury to the liver, kidneys, and adrenals (American Nat.
Standards Inst., 1970; AIHA, 1956, 1965) . The accidental oral
ingest ion of a single dose of 0.5 - 1.0 g/kg has been reported to
result in death; autopsy revealed liver necrosis and focal
adrenal degeneration and necrosis (Wirtschafter and Schwartz,
1939; Yodaiken and Babcock, 1973).
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27
B. Observations In other Species
Acute effects- The acute oral LD50 of 1,2-dichloroethane has
been established at 0.77 (0.67-0.89) ml/kg in rats (Smyth et al.,
1969). LCSO values for vapor inhalation are 12,000 ppm in 0.53
h, 3,000 ppm in 2.75 h, and 1,000 ppm in 7.20 h in rats (Spencer
et al., 1951). In one study with rabbits, the LDSO for skin
penetration was determined to be 3.89 (3.40-54.116) ml/kg. The
toxic effects of single acute exposures to 1,2-dichloroethane
were central nervous system depression, lung irritation, and
injury to the liver, kidneys, and adrenals (Gohike and Schmidt,
1972).
Chronic effects. When animals were exposed to 1,2-
dichloroethane vapor for 7 h/day, 5/days/week, for 6 months, the
maximal concentrations that produced no adverse effect were 400
ppm in rabbits, 200 ppm in rats, and 100 ppm in monkeys and
guinea pigs (Heppel et al., 1946; Yllner, 1971) . Significant
chronic changes at higher concentrations included hepatic and
renal dawage. In other chronic studies, 500 ppm was not
tolerated by rats, guinea pigs, or rabbits, and siqniticant
mortality occurred in the first 2 weeks; more than 907. of the
animals were dead by the end of the fourth week. All the animals
tolerated 100 ppm for a 17-week period (Yllner et al., 1971;
Hofman et al., 1971).
Muta«renicity. Brem et al., (1974) have reported a mutagenic
effect of 1,2-dichloroethane in S. typhimurium and DNA
polymerase-deficient E. coli. It was the weakest, however, of
the series of haloalkanes tested.
Carcinogenicity. No available data.
Teratogenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
1,2-Dichloroethane has been shown to be weakly mutagenic in
two different mutagenicity screening tests. There is no dati.
available on its potential caccinogenicity.
In view of the relative paucity of data on teratogenicity,
carcinogenicity, and long term oral toxicity of 1,2-
dichloroe thane, estimates of the effects of chronic oral exposure
at low levels cannot be made with any confidence. It is
recommended that studies .to produce such information be conducted
before final limits in drinking water can be established.
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3. OTHER FUNGICIDES
HEXACHLOROBENZENE
I. IMTRODUCTIOH
Hexachlorobenzene (HCBr Anticarie, Perchlorobenzene)
introduced a's a cereal and seed treatment in 1945 and is
registered in the United States as a fungicide for various
cereal, vegetable, and other crops (Thomson, 1975). Tj.S.
production for pest control is estimated at only-700,000 pounds
(HAS, 1975), but HCB is encountered in much larger quantities as
an intermediate or waste byproduct in various chemical syntheses,
including that of pentachlorophenol, and as a contaminant of
other pesticides, such as technical pentachloronitrobenzene
(Borzelleca et al., 1971) and CCPA (Kimbrough and Linder, 1974).
HCB has also been identified as a prominent constituent of the
air collected in the vicinity of a plant manufacturing
perchloroethylene (Mann et al., 1974).
HCB is produced commercially by exhaustive chlorination of
benzene in the presence of a catalyst (Spencer, 1973). Analysis
of three commercial HCB preparations showed that they contained
pentachlorobenzene at 100-81,000 ppm (0.02-3.1%),
octachlc rcrUbenzo-£-dioxin at 0.05-212 ppm, and
octachlorodibenzofuran (ocva-CDF) at a.35-58.3 ppm (Villanueva e_t
al., 1974). HCB has a very low solubility in water: only 6 ppb
(La and Met calf, 1975) .
HCB is extremely lipophilic and resistant toward degradation.
It has been identified in the tissues of marine birds (Gilbertscn
and Reynolds, 1972), predatory birds (Cromartie et al. r 1975; vos
et al», 1968), and starlings (dickerson and Barbehann, 1975) ;
surface water (Heczel, 1972); freshwater (Johnson et al-, 1974)
and marine (Zitko, 1971) fish; anA other aquatic organisms
(Koeman et al., 1969). BCB residues in-edible freshwater fish
reached 0.34 ppm, and in one case carp contained 62 ppm (Johnson
et al., 1974). Marine fish oils contained 0-06-0.38 ppm.
BCB residues have also been found in human adipose tissue anc
blood from different parts of the world (Abbott et al., 1972;
Acker and Schutle,- 1970r Brady and Ciyali, .1972;,Burns and
Miller, 1975: Curley et al., 1973; Siyali, 1972) Win-human- milk
(Graca et al., t974; Stacey and Thomas, 1975), ard in food
products (MansIce and Comeliussen, 1974; Manske and Johnson,
t975; Smyth, 1972). The EPA established interim HCB tolerances
of 0.5 ppm in the fat of cattle £».d other domestic* animal? and
0.3 gpm in fat or milk, and other dairy products:/
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29
HCB has been detected at 0.010 ppb in raw and 0.006 ppb in
finished U.S. drinking water (USEPA, 1975J).
II. METABOLISM
In studies on the fate of [l«C]HCB in rats after intravenous
administration, only 0.7 and 0.1% of trie dose was recovered in
feces and urine, respectively, over a 48-h period, and there was
no conversion of the labeled HCB to [**C]carbon monoxide or other
volatile radioactive metabolites (Yang and Pittman, 1975). Fat
contained the highest radioactivity.
seven days after a single 5-mg/kg oral dose of [»*C]HCB in
jdult male rats, approximately 16% of the dose had been excreted
in the feces and less than 1% in the urine (Mehendale ct al.,
1975); 70% of the dose remained in the animal, with fat as the
:najor depot. Metabolites in the urine included
nentachlorobenzene, tetrachlorobenzene, pentachlorophenol, and
four unknown compounds. The half-life of HCB in rats was found
to be about 60 days (Morita and loshi, 1975). Storage of
dieldrin in the adipose tissue of rats is markedly decreased by
HCB in the diet (Avrahami and Gernert, 1972).
In studies with rhesus monkeys, 17.1 and 1.8% of an
Intravenous dose of [**C]KCE was excreted in feces and urine,
respectively, over a period of 100 days (Yang and Pittman, 1975).
•\s in rats, fat retained the highest amount of radioactivity.
In another study (Villeneuve, 1975), adult male Sprague-
Dawley rats received HCE at 1, 10, and 100 mg/kg for 14 days and
the tissues were then analyzed for HCB. Two other groups, after
14 days of HCB feeding, were either fed an HCB-free diet ad
libitum for 10 days or fed 25% of their normal food intake over
^He~same period. HCB concentrations in tissues were fat > liver
> Jungs > kidneys > brain > spleen > heart > muscle > plasma. No
appreciable losses of HCE occurred in the tissues over a 10-day
period in the animals placed on a diet free of HCB. Animals fed
restricted quantities of the HCB-free diet, however, showed a
mobilization of HCB stored within fat depots, which resulted in
transfer of the compound into plasma and other tissues. Death
occurred in the animals when brain HCB concentration exceeded 300
ppm.
AOSS et al., (1975, 1976) have recently studied the
jharmacokinetics and metabolism of HCE in rats.
In vitro conversion of HCB to pentachlorophenol has been
l^morTstrated in rat liver microsomal preparations (Lui and
Sweeney, 1975), and a dechlorination system requiring reduced
-------
nicotinamide adenine dinueleotide phosphate in the liver and
other tissues was found by Mehendale et al. (1975).
HCB crosses the placenta and accumulates in the frtus in a
dose-dependent manner (Andrews and Courtney, 1976; Courtney et
al., 1976; Villeneuve et al. , 1974; Villeneuve and Hifrlihy,
1975). In rats, the maternal liver had the higher.t WE residue,
followed by fetal liver, whole fetus, and fetal brain (Villeneuve
and Hierlihy, 1975). This is in contrast with the results in
rabbits, in which fetal liver contains HCB at concentrations 2-4
times higher than maternal liver.
III. HEALTH ASPECTS
A. Obsoryations in Man
In the period 1955-1959, an outbreak of human poisoning
occurred in Turkey as a result of the consumption of HCB-treated
wheat (Cam and Nigogosyan, 1963; DeMatteis et a_l., 1961; Schmid,
1960) . Some deaths resulted, but the major syndrome was
cutaneous porphyria, with skin lesions, porphyrinuria, and
photosensitization. The estimated dosage was approximately 50-
200 mg/day (0.71-2.9 mg/kg/day) for presumably long periods
before toxic manifestations became apparent (Cam and Nigogosyan,
1963; Schmid, 1960).
B- Observations in Other Species
Acute Effects. The acute toxicity of HCB is relatively low,
as evidenced by oral LD50 values of 3,500 mg/kg in rat?, 2,600
mg/kg in rabbits, and 1,700 mg/kg in cats (Christensen et al.,
1971). In another report (Spencer, 1973), the acute oral LD50 in
rats was given as 10,000 mg/kg.
Subchronic and Chronic Effects. HCB is considerably more
toxic on prolnged~exposure.. Mortalities and severe weight loss
occurred among Wistar rats and guinea pigs receiving daily 500
mg/kg oral doses of pure HCP over a period of 9-16 days
(Villeneuve and Newsome, 1975) . In a study by Haze It on
Laboratories (USKPA, 1973c) , rats were fed HCB at 5, 25, 125, and
625 ppm for 13 weeks. At 125 ppm, liver:body weight ratios were
increased, and there were pathologic effects on the liver. No
adverse effects were noted in animals fed 5 and 25 ppm.
In a study by Dow Chemical Company, gross and histopathologic
alterations occurred in the livers of female weanling rats fed
HCB at 30, 65, and 100 mg/kg/day for 30 days (USFPA, 1973c). No
adverse changes were observed in rats fed 1, 3, or 10 mg/kg/day.
In a second study by the same group, rats fed 20 mg/kg/day for 13
days developed neurotoxic symptoms and increased liver:body
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31
weight ratios; at 6 mg/kg/day, there was only slight skin
twitching and nervousness, but a significant increase in
liver:body weight ratio; no toxic effect was seen at 2 mg/kg/day.
Rats and rabbits fed HCE at 5,000 ppm in the diet died in 8-
12 weeks, after showing severe neurologic symptoms (DeMatteis et
al.i 1961). There was a substantial increase in urinary
porphyrin excretion after about 6 weeks; at death, there was
substantial tissue porphyrin deposition in the animals. Guinea
pigs and mice were much more susceptible to HCB; animals fed
5,000 ppm died after 8-10 days with marked neurologic signs.
Before death, the latter animals developed moderate to severe
porphyria.
Male and female Charles River rats received diets containing
HCB at 0.5, 2.0, 8.0, and 32.0 mg/kg/day over a period of 12
weeks (Kuiper-Goodman et al., I975a). Female rats were more
sensitive than males to the toxic effects of HCB: 26% of the
females and none of the males died at the highest dosage.
Females also developed more severe porphyria, with high porphyrin
concentrations in the liver. Males at the two highest dosages
showed a siginificant increase in liver weight, and this was
correlated with increased hepatic mixed-function oxidase activity
and increases in the smooth endoplasmic reticulum. Additional
information (Kuiper-Goodman et al., 1975b), presumably on the
same study, indicated that tissue HCB residues had reached a
plateau before 104 days. Tissue HCB concentrations were highest
in adipose tissue, after which the order was liver > brain >
serum. At the two highest dosages—8.0 and 32.0 mg/kg/day—
liver:body weight ratios were increased in both sexes.
Pathologic examination showed increased hepatocyte size due to
proliferation of smooth endoplasmic reticulum. This was
correlated with increased activities of drug metabolizing
enzymes, which persisted long after animals were placed on an
HCB-free diet. Females developed porphyria, which persisted
after the rats were removed from the HCB diets.
Chronic ingestion of HCE at 2,000 ppm in the diet of adult
male Sprague-Dawley rats resulted in hepatocellular degeneration
and increases in the amounts of porphyrin and porphyrin
precursors in the liver and excreta (Ocker and Schmid, 1961).
Male and female Sprague-Dawley rats were fed diets containing
HCB at 10, 20, 40, 80, and 160 ppm for 9 or 10 months (Grant et
al., 1974). Porphyria developed in rats fed 40 ppm and above,
and the prophyria was much more severe in females than in males.
Weight gains were reduced in female rats fed 80 and 160 ppm.
Rats of both sexes showed increased liver:body weight ratios
after receiving 80 or 160 ppm. Hepatic mixed-function oxidase
activity was increased in male rats fed 40 ppm or more, but was
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32
unaltered in females. The pharmacologic activities of
pentobarbital and zoxazolamine, however, were shortened in rats
of both sexes fed 20 ppm or above. HCB residues in liver were
similar in males and females and were dose-dependent.
Groups of weanling Sherman rats were fed technical HCB at
100, 500, and 1,000 ppm for a 4-month period (Kimbrough and
Linder, 1974). No rats died in the control and 100-ppm groups, 2
of 10 males and 14 of 20 females died at 500 ppm, and 3 of 10
males and 19 of 20 females died at 1,000 ppm. Increased ratios
of liver, spleen, adrenal, lung, and kidney weights to body
weights were found in weanling Sherman rats fed 500 and 1,000
ppm. Hyperplasia of the adrenal cortex and lung degeneration
were observed in all HCB-fed groups, particularly in females.
Pathologic effects on liver and heart were found in rats
receiving 500 ppm and above, with females snowing the most severe
effects. Hemoglobin and hematocrit values were significantly
decreased in females fed 100 ppm or more and in males fed 1,000
ppm.
Mixed-Function Oxidase Activity and Porphvr ia. HCB has been
shown to be associated with the production of porphyria in humans
and experimental animals (Cam and Nigogosyan, 1963; DeMatteis et
al., 1961; Ocker and Schmid, 1961). In HCB-treated animals,
there are substantial increases in liver weight, in smooth
endoplasm" c reticulum,, in mixed-function oxidase activity, and in
uytochi .,1,. J - j.-it.n*- (Carl? and Tardiff, 1975; Grant et
al., 1974; Kuiper-Goodman et al. , 1975a,fc; Turner and Green,
1974; Wade et al., 1968). It is noteworthy that HCB apparently
induces primarily the hepatic cytochrome P1-450 system, rather
than the P-450 system (Turner and Green, 1974).
Porphyria resulting from ingestion of HCB is much more severe
in female than in male animals (Grant et al., 1974). HCB is
known to induce increased activity of mitochondrial 5-
aminolevulinic acid (ALA) synthetase (Myakoshi and Kikuchi,
1963). The HCB-induced porphyria, however, is not simply related
to an increase in ALA synthetase activity, inasmuch as a twofold
increase in the activity of that enzyme (the rate-limiting step
in heme synthesis) cannot explain the observed massive increase
in porphyrins in HCB-treated animals (Wada et al., 1968).
Moreover, although hemin normally exerts a feedback function to
suppress ALA synthetase activity, HCB porphyria cannot be
suppressed by hemin (Strik, 1973).
Recent evidence (Sweeney, 1976) suggests that a contaminant
of technical HCB may be more active than HCB in producing
porphyria in experimental animal- PerpHr»x develops in alee
fed tecvii -al HCB at 1,000 ppi -n about =• .-ks , To nrceiuce t ,«-
baa <.? of po~ rr:'. in 6 s eY :•, in nn e vi\:h pure C>~4, It was
-------
necessary to feed 2,500 ppm. Sweeney also presented preliminary
evidence that HCB is actually converted by mixed-function oxidase
systems in the liver to a reactive metabolite that then
covalently binds to tissue macromolecules and that this produces
the porphyria.
Mutagenicity. For dominant-lethal tests, H groups of 15 male
Wistar rats each were given HCB orally at 20, 40, or 60 mg/kg for
10 consecutive days (Khera, 1974). After mating trials, there
were no significant differences between test and control groups.
Carcinogenicity. HCB is currently being tested for
carcinogenicity (IAFC, 1971, 1975).
Reproduction. HCB at dietary concentrations of 10, 20, 10f
80, 160, 320, and 640 ppm was fed to Sprague-Dawley rats, and
four generations of rats were raised (Grant et al., 1975). The
two highest dietary concentrations were toxic to the F
generation, and 50 and 20%, respectively, of the females died.
The viability index was zero in the F a and F b generations for
rats fed 320 and 640 ppm and only 55% for the 160-ppm group. The
lactation index decreased from 30% for the F a and F b generation
pups to 0% for the F2a and F2b generation pups in the 160-ppm
group, from 93% in the F generation to 40% in the F
generation in the 80-ppm group.
Teratogenicity. No gross abnormalities were present in rat
pups, but weight gain was affected by HCB treatment.
Teratogenic studies were carried out in Wistar rats given HCB
in single daily doses of 10, 20, 40, 60, 80, or 120 mg/kg on days
6-9, 10-13, 6-16, or 6-21 of gestation (Khera, 1974). The 80-
and 120-mg/kg doses caused maternal neurotoxicity and a reduction
in fetal weight. In the fetuses, the incidence of unilateral and
bilateral fourteenth rib was significantly increased over control
values when doses of 20 mg/kg/day or more were administered on
days 10-13, 6-16, or 6-21 of gestation. Sternal defects in the
fetus were observed after 20 mg/kg/day on days 6-21 of gestation.
Because these effects were not reproduced in later trials at up
to 80 mg/kg given during the period of organogenesis, however,
the teratogenic potential of HCB in the rat is doubtful. Oral
administration of pure HCB at 100 mg/kg to CD-1 mice on days 7-16
of gestation, however, produced cleft palates and some kidney
malformations (Courtney et al., 1976).
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IV. CONCLUSIONS AND RECOMMENDATIONS
. The acute toxicity of HCB is relatively low, but subchronic
or chronic exposure of laboratory animals or humans to HCB
results in the development of severe porphyria, especially in
females. An ADI was calculated at 0.001 mg/kg/day based on a 10-
month feeding study in rats. The toxicity data and calculations
of ADI are summarized in Table VI-U3. A conditional acceptable
daily intake of 0.0006 mg/kg/day was derived by the FAO/WHO as
the upper limit for residues. The FAO/WHO suggested extreme
caution with the compound and indicated that available
information is insufficient to establish a firm acceptable intake
for HCB.
HCB can be readily determined by electron capture gas
chromatography at concentrations as low as 0.0001 ppb.
There are a number of puzzling differences in the highest no-
effect and lowest-minimal-toxic-effect dosages found for HCB in
rats (Table VI-U3). These differences may be the results of
using different rat strains or different HCB formulations in the
various studies. They may also result from the use of HCB of
uncertain purity. The source of the observed variations should
be established. No subchronic- or chronic-toxicity studies have
been conducted with HCB in mammalian species other than rats. It
is especially important to conduct 2-year feeding experiments and
carcinogenicity studies with HCB in two species, because HCB has
been found to be extremely toxic on long-term exposure and is on
the list of suspected carcinogens.
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j;ABLE VI-43. Summary of Toxicity Data for HCB
Dosage Level and Highest No-adverse-
Duration Number of Animals Effect Level or Lowest Effect
Species of Study per Group Minimal-Effect Level Measured Reference
Quail 90 days 0-80 ppm in diet, 1 ppm (O.lU ng/kg/day)4 no toxic Vos et al.,
15 animals,per group effect 1971
Rat 9-10 months 0-160 ppm in diet, 20 ppm (l mg/kg/day)°* reduced sleep- Grant et al.,
12 animals, per group ing time 1971*
Rat 13 weeks O-625 ppm in diet 25 ppra (1.25 mg/kg/day)d no toxic EPA, 1973c
effect
Rat 13 weeks 0-200 mg/kg/day 2 mg/kg/day no toxic EPA, 1973c
orally, 5 animals effect
per group
Rat 12 weeks 0-32 mg/kg/day 2 mg/kg/day no toxic Kuiper-Goodman
orally, 1^0 effect et al., 1975a,
animals per group 1975b
Rat k months 0-1,000 ppm in diet, 100 ppm (5 mg/kg/day) adrenal hyper- Kimbrough and
3O animals per group plasia and Linder, 197*+
hematologic
effects
Rat 30 days O-100 mg/kg/day 10 mg/kg/day no toxic EPA, 1973c
effect
Using an uncertainty factor of 1,000, suggested no-adverse-effect level in
drinking water is calculated as follows:
1 e 0.001 mg/kg/day (ADI), 0.001 x 70* x 0.1 - 0.007 mg/liter.
1,000
a
Assume average weight of human adult « 70 kg.
b .
Assume average daily intake of water for man « 2 liters, and that 20% of total intake
is from water.
c
Test study from which to calculate suggested no-adverse-effect level.
Assume weight of rat » O.1* kg and average daily food consumption of rat « 6.02 kg.
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»r*»
oo
PI(2-ETHYLHEXYU PHTHALATE
I. INTRODUCTION
Di(2-ethylhexyl)phthalate (DEHP) is commercially produced by
the reaction of 2-ethylhexyl alcohol and phthalic anhydride. It
is used in the manufacture of plasticizer, plastics, and organic
pump fluid (EPA, 1975d). The United States production of di(2-
ethylhexyl) phthalate in 1973 was over 378 million pounds (USITC,
1975) .
Di(2-ethylhexyl)phthalate is insoluble (CRC Handbook of
Chemistry and Physics, 1970-1971) and biologically persistent in
water (EPA, 1975d). Pour of the 10 finished-waters analyzed by
EPA contained this compound; the highest concentration was 30
pg/liter in Miami (EPA, 1975a). The Region V survey indicated
that di(2-ethylhexyl)phthalate was present in 20 of 53 finished-
water supplies; the highest concentration was 17 tig/literf in
Cincinnati (EPA, 1975b).
II. METABOLISM
Shaffer et al. (1945) studied the metabolism of di(2-
ethylhexyl)phthalate in rats, rabbits, dogs, and man, and it was
shown to be hydrolyzed in all four. Oral doses were not
completely absorbed. Dogs excreted 4 - 5% of an oral 2 g/kg dose
as phthalate in 3 days, but rabbits excreted 26 - 65% phthalate
in the same period. In man, 4 - 5% of a 10 g dose has been shown
to be excreted as phthalate in the urine.
Williams and Blanchfield (1974) gave [i«C]DEHP as a single
oral dose or in the diet to rats and found only limited retention
and accumulation. Virtually all was excreted in urine or feces
within 18 h. If the concentration was over 0.2% of the diet, the
metabolic products were found in the feces. If only 10 ppm was
fed, all excreted metabolic products were in the urine.
Intravenous injected [»*C]DEHP in rats at 0.1 mg/kg was almost
totally excreted as water-soluble metabolites in 24 h, according
to Schulz and Rubin (1973).
II. HEALTH ASPECTS
A. Observations In Man
A dose of 10 g of DEHP in humans caused mild gastric
disturbance and catharsis (Shaffer et al., 1945).
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37
Teratogenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
There is one report suggesting that topical 1,2-
dichlorophenol may act as a co-carcinogen in promoting papillomas
and carcinomas in mouse skin.
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity, and long term oral toxicity of
2, U-dichlorophenol, estimates of the effects of chronic oral
exposure at low levels cannot be made with any confidence. It is
recommended that studies to produce such information be conducted
before limits in drinking water can be established.
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Di-n-BOTYLPHTHALATE
I. INTRODUCTION
Di-n-butylphthalate PBP) is used in the manufacture of
plasticizers, plastics, and in cosmetics, explosives, solid
rocket propellant, textile lubricating agents, safety glass,
insecticides, printing inks, paper coatings, and adhesive (EPA,
1975d). The United States production of di-n-butylphthalate in
1973 was about 38 million pounds (USITC, 1975).
This compound is insoluble in water (CPC Handbook of
Chemistry 6 Physics, 1970-1971) and very persistent in the
environment (EPA, 1975d). Six of the 10 water supplies surveyed
by the EPA (1975a) contained di-n-butyl phthalate; the highest
concentration was 5 pg/liter in Miami.
II. METABOLISM
Williams (1959) suggested that di-n-butylphthalate is one of
the phthalate esters likely to be hydrolyzed in vivo, yielding
phthalic acid and an alcohol. No accumulation of
dibutylphthalate or monobutylphthalate was found by Williams and
Blanchfield (1975) in tissues of rats fed di-n-butylphthalate at
1 g/kg of feed for 12 weeks. These authors reported that 80-90%
of a dose of [ «*C]di-n-butylphthalate was metabolized and
excreted in the urine~in 48 h. Phthalic acid, monobutyl
phthalate, mono(3-hydroxybutyl)phthalic acid, and mono (4-
hydroxybutyl) phthalate were found in the urine. Smith (1953)
found that DBF was hydrolyzed in vitro by pancreatic lipases;
this suggested that it is metabolized like fat that is normally
in the diet.
III. HEALTH ASPECTS
A. Observations in Man
Pairhall (1957) reviewed a report of an accidental ingestion
of 10 g of DBP. Hours after ingestion, the patient was nauseous
and giddy. His eyes were inflamed and painful, with photophobia
and lacrimation. Toxic nephritis occurred, and his urine
contained red and white cells and albumin. The patient recovered
fully.
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B. Observations in Other Species
Acute effects. Di-n-butylphthalate has low acute and chronic
toxicity. The single-dose oral LD50 in animals is reported to be
9 g/kg (Smith, 1953) and 12.5 g/kg (Nikonorow et al. , 1973). The
intraperitoneal LD50 is reported to be 6.76-4.0 g/kg in mice
(Hodge et al., 1942; Karel et al., 19U7; Galley et al. , 1966).
Chronic effects. Smith (IS53) fed rats a diet of 1.25% DPP
for a year. The dose was 1r600 mg/kg at the start and 525 mg/kq
at termination. Half the rats died in the first week; those
sacrificed at a year had no specific gross or microscopic
pathologic effects. Nikonorow et al. (1973) fed rats 0.125% of
DPB in the diet for a year and recorded six deaths in the 40
rats, compared with four in ^Q untreated control rats. Daily
intubation 'of 0.12 g/kg and 1.20 g/kg for 3 months croduced only
a single death at the high dosage in rats (Piekacz, I971a). Both
dosages were reported, however, to produce enlargement of the
liver. Shibko and Blumenthal (1973) reported no effects in dogs
given 18 mg/kg/day for a year.
Mutagenicity. No available data.
Carcinogenicity. No chronic studies with animals have
revealed signs of carcinogenesis at the time of death.'
Teratogenicity. Teratogenic effects of DBF were identified
in a study by Singh et al, (1972a). Fats were given one-tenth,
one-fifth, and one-third of the LD5O (3.2 g/kg) intraperitoneally
on day 5, 10, or 15 of gestation. Partially dose-related
resorption and a 20 - 30% incidence of skeletal abnormalities
were found at the high dosage. Studies by Bower et al. (1970) in
chicken eggs showed 79% mortality at 0.1 ml, 67% at 0.05 ml,
compared with 47% for the oil controls.
Reproduction. Reproduction studies reported by Piekacz
(1971b) included treating female rats with DBP at 0.60 and 0.12
mg/kg for 3 months before mating. The low dosage produced two
resorptions, the high dosage 22, and the controls four, Piekacz
(1971b) also gave rats DBP orally daily at 1% or 5% of the LD50
for 12 weeks. The numbers of fetuses and resorption sites were
statistically different in the 5% goup as compared to the
controls. Other groups of 10 rats were intubated daily with 1%
and 5% of the LD50 during pregnancy. The number of fetuses was
reduced, and resorptionc increased. DBP had a greater adverse
effect than di (2--ethylhexyl) phthalate, with which it was
compared.
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IV. CONCLUSIONS AND RECOMMENDATIONS
The major effect of di-n-butylphthalate in animals involves
disturbances in reproduction and teratogenicity. There is no
data available on rautagenieity and the chronic feeding studies
did not show any carcinogenesis.
An ADI was calculated on the basis of the chronic toxicity
data. Based on these data the ADI is 0.11 mg/kg/day. The
calculations and available chronic toxicity data are summarized
in Table VI-50.
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41
HEXACHLOROETHANE
I. INTRODUCTION
Hexachloroethane (HCE) is used in organic synthesis, as a
retarding agent in fermentation, as a substitute for camphor.in
nitrocellulose, in pyrotechnics and smoke devices, and in the
manufacture of explosives, solvents, and medicines. It can be
formed in small quantities by chlorination (EPA, 1975) . It is
insoluble in water and very persistent. Of the 10 water supplier
surveyed by the EPA (1975a), only Miami's finished water
contained hexachloroethane, at 0.5 pg/liter.
II. METABOLISM
Hexachloroethane was detected as a metabolite of
carbontetrachloride in rabbits following a 1 ml/kg dose in olive
oil. Fat contained the highest concentration of HCE, muscle the
lowest; tissue concentrations reached a peak at 21 h, but
persisted for as long as 44 h (Fowler 1969).
III. HEALTH ASPECTS
A. observations In Man
No studies have been conducted to examine the acute,
subchronic, or chronic effects of hexachloroetharf in man.
B. Observations In Other Species
Acute effects. The Toxic Substances List (1974) notes that
the lo^elt reported acutely lethal dosages of HCF are 325 mg/kg
administered -intravenously in dogs and 4,000 mg/kg administered
subcutaneously in rabbits.
In a study of the subacute effects of hexachlorethane by
Tugarinova et al. (1963), 12 mice received 310 mg/kg orally once
a day for 10 days. Macroscopic examination of the animals
revealed no cumulative effects.
Chronic effects. Chronic experiments with 19 male rats
(weigl^nT^OO^T^O g) and 12 female and eight male rabbits
weighing (2,100 - 2,800 g) given hexachloroethane oraily at O.Ob
m/kq/day for 5.5 months showed no signs of toxicity measured by
body weight, motor reflexes, and blood chemistry.
HistoPathologic evaluation of brain, heart, liver, kidneys,
spleen^ s?omach. and intestine were negative (Tugarinova et al. ,
1963) .
Mutaaenicity. No available data.
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Garcinogenicity. No available data.
Teratoqenicity. No available data.
V. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the mutagenicity,
careinogenicity, teratogenicity, and long term oral toxiciy of
hexachloroethane, estimates of the effects of chronic oral
exposure at low levels cannot be made with any confidence. It is
recommended that studies to produce such information be conducted
before limits inl drinking water can be established.
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43
POLYCHLORINATEC BIPHENYLS
I. INTRODUCTION
Polychlorinated biphenyls (PCB's) are mixtures of chlorinated
biphenyls produced commercially by the chlorination of biphenyl.
PCB's are used in the production of capacitors and transformers.
PCB's are highly persistent and can accumulate in the
environment. They are soluble in water at 0.04 - 0.2 ppm.
Trichlorinated, tetrachlorinated, and pentachlorinated biphenyls
have been detected in a few water supplies: at 3.0 ng/liter in
Winnebago, Illinois, and 0.1 pg/liter in Sellersberg, Indiana
(EPA, 1975b) .
II. METABOLISM
Oral feeding of a single dose of PCB's to rodents and rhesus
monkeys has shown that intestinal absorption is rapid and 90*
complete (Albro and Fishbein, 1972) Allen and Norback, 1976,
Berlin et al., 1973). The feces provide the major route of
excretion; only traces of PCB's could be found in the urine of
the animals. When the analysis of feces is limited to the
determination of unchanged PCE's, the recovery of the
administered dose is incomplete (Platonow et al., 1972).
Berlin et al. (1975a,b) demonstrated that after a single oral
dose of a [ i*C jpentachlorbiphenyl, radioactivity rapidly entered
the circulation and was distributed in the tissues, particularly
in liver, kidneys, lungs, and adrenals; within 24 h, it had
migrated to the fat, which remained the major reservoir of
unchanged PCB's in the body, until only traces remained after i2
days,
The degradation and elimination of PCE congeners appear to
take place via t> 2 hepatic microsowal enzyme system. Tvo
possible mechanirms for biotransformation have been suggested b>
Ecobichon (1976). The first and most rapid mechanism involves
the formation of an arene oxide intermediate and reguires the
presence of unsubstituted adjacent carbon atoms in the nuclei^
The second and much S-jwer uses a different hydroxylation sys em
for isolated unsubstituted positions, as are found in highly
chlorinated biphenyls. Two adjacent unsubstituted carbon atoras
appear to be important in metabolism, in that their presence
facilitates the formation of arene oxides by the hepatic mixed-
function oxidases.
Polvchlorinated biphenyls are known to be strong 5nducers
her>atic mixed-function oxidase enzymes. The potency increases
wt?n in\basing chlorination of the biphenyl rings. The PCB's
-------
are somewhat unique in this regard in that they induce both type
I and Type II P-t|50, but this may be due in part to contaminants
in the PCB's tested (HEW, 1976).
These effects raise a concern that such induction may
increase metabolism of birth control hormones with possible
harmful effects. Also to be considered is the possibility that
environmental carcinogens may be activated at a faster rate (HEW
1976) .
III. HEALTH ASPECTS
A. Observations in Man
PCB's are liver toxins and cause chloracne and possibly
peripheral neuropathy in man (Murai and Juroiwa, 1971) .
There is no information on acute adverse effects on humans.
Although Yusho disease (an acute outbreak of disease which
occurred in Japan) has generally been ascribed to the ingestion
of PCB's in rice oil (0.07 mg/kg/day for at least 50 days),
recent evidence provided by Kuratsune et al. (1976) suggests that
the rice oil was contaminated with polychlorinated dibenzofurans
(PCDF's) . These compounds may have played a significant role in
the observed toxicity. Initial measurements of the
concentrations of PCDFls in the PCB's suggested that these
materials contributed at least as much to the toxicity as the
PCB's themselves. Symptoms included excessive fatigue, headache,
phymata in articular regions, fever, cough, digestive
disturbances, numbness, and menstrual disorders. Physical signs
consisted primarily of cutaneomucosal abnormalities, such as
acneiform eruptions and black comedones on face, buttocks, and
intertriginous sites; increased pigmentation of face, palpebral
conjunctiva, gingiva, and nails; ocular signs consisting of
swelling and hypersecretion of the meibomian gland and palpebral
edema.
Recent surveys have indicated that PCB can be found in the
milk of nursing mothers. The highest reported level was 10.6 ppm
with a mean of 1.8 ppm for all samples (HEW, 1976) .
This information is especially meaningful in light of Allen's
recent work (1975). Female rhesus monkeys orally exposed to 2.5
and 5.0 ppm of PCB (Aroclor 1248) developed facial acne,
erythema, subcutaneous edema conjunctivitis and loss of
eyelashes. All infants born to PCB exposed mothers had PCB's in
their tissues at birth. These infants also developed skin
lesions as a result of nursing PCB contaminanted milk. Fifty
percent of the infants died within 4 months.
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B. Observations In Other Species
Acute effects. Oral LDso*s of several Arachlor's (a trade
name in which the last two digits indicate the percent
chlorination) agents have been determined in rats: Arochlor
1240, 4.25 g/kg (Bruckner et al. , 1973); Arochlor 1254, 1.3 - 2.5
g/kg (Grant and Philips, 1974); Arochlor 1254, 4-10 g/kg in
female Sherman rats (Kimbrough et al., 1972); and Arochlor 1254
and 1260, 1,295 and 1,315 mg/kg, respectively, in weanling rats
(Kimbrough, 1974) .
Subchronic and chronic effects. Tucker and Crabtree (1970)
reported deaths in rats fed Arochlor 1 g/kg for 28-53 days.
Repeated daily oral administration of 300 mg of Aroclor 1221,
1242, or 1254 in rabbits for 14 weeks produced liver enlargement
and damage and one death with Aroclor 1254, but only minor
changes with Aroclor 1221 (Koller and Zinkl, 1973) . Allen et al.
(1974) administered Aroclor 1248 at 25 mg/kg of diet to six
female rhesus monkeys for 2 months, with production of facial
edema, loss of hair, and acne a month after onset of feeding.
Mink on diets containing PCE at 30 mg/kg (Aroclor 1242, 1248, and
1254 at 10 mg/kg each) demonstrated 100% mortality within 6
months (Aulerich et al., 1973). Female mink fed a diet
supplemented with Aroclor 1254 at 5 mg/kg for 9 months failed to
produce offspring (Ringer et al., 1972).
The oral administration of Aroclor 1242, 1254, and 1260 in
rats for 18 months at 1, 10, and 100 mg/kg (Keplinger et a]_.,
1971) produced adverse effects only at 100 mg/kg. With Aroclor
1242 and 1254, there was an increase in liver weight and a
reduction in litter survival at 100 mg/kg. Kimbrough et al.
(1972) reported experiments in which male rats survived Aroclor
1260 at 1 g/kg for 8 months, but eight of 10 females died at this
dosage. With both Aroclor 1254 and 1260, there was a significant
dose-dependent increase in liver weight in male rats down to 20
mg/kg in the diet; in female rats, liver enlargement occurred
only at 500 mg/kg and higher.
The rhesus monkey is the only animal reported to show signs
of poisoning similar to those seen in Yusho patients. Oral
administration of Aroclor 1248 at 2.5 and 5.0 mg/kg pro-iur-M
periorbital edema, alopecia, erythema, and acneiform e/u^tiors
within 1 - 2 months. At 25 mg/kg, one of six died; at 100 and
300 mg/kg, the mortality approached 100% in 2 - 3 months.
Survivors still showed signs of poisoning 8 months after exposure
was discontinued (Allen and Norback, 1973; Allen et al. , 197/i,
Allen, 1975).
MutaaenicitY- Aroclor 1242 and Aro-lor 125« have not her
found~to have mutagenic potential when administered :n rat::
-------
single or repeated large daily doses (Green et al., 1975), when
assessed by cytogenetic analysis of bone marrow and
spermatogonia.
Careinoqenicity. There have been a number of carcinogenic!ty
studies with mice and rats treated with combinations of PCBfs.
Only the study of Kimbrough et al. (1975) provided a true long-
term chronic feeding study. They fed Sherman female rats Aroclor
1260 at 100 mg/kg in their diets for 21 months and sacrificed
them at 23 months. At this dosage, 26 of 184 in the experimental
group and one of 173 in the controls had hepatocellular
carcinomas.
Teratogenicity. One study (Kato et al., 1972) demonstrated
that PCBfs could cross the placenta but produced no defects.
Other studies (Funatsu et al., 1972; Miller, 1971) have linked
maternal ingestion of PCB with dark-brown staining of the skin of
newborn babies.
IV. CARCINOGENIC RISK ESTIMATES
Only the study by Kimbrough et al. (1975) is of sufficient
duration to permit a statistical extrapolation of risk to man.
The available set of dose response data was considered as
described in the risk section in the chapter on margin of safety.
The set of dose response data was used to statistically estimate
both the lifetime risk and an upper 95% confidence bound on the
lifetime risk at the low-dose level. These estimates are of
lifetime human risks and have been corrected for species
conversion on a dose per surface area basis. The risk estimaes
are expressed as a probability of cancer after a lifetime
consumption of 1 liter of water/day containing Q ppb of the
compound of interest. For example, a risk of 1x10~6 Q implies a
lifetime probability of 2x10-s of cancer if 2 liters/day were
consumed and the concentration of the carcinogen-was 10 ppb (i.e,
Q-10). This means that at a concentration of 10 ppb during a
lifetime of exposure this compound would be expected to produce
one excess case of cancer for every 50,000 persons exposed. If
the population of the United States is taken to be 220 million
people this translates into 4,400 excess lifetime deaths from
cancer or 62.8/year. For the PCB Arochlor 1260 at a
concentration of 1 pg/liter (Q=1) the projected risk for man is
2.2 x 10-* Q. The upper 95% confidence estimate of risk at the
same concentration is 3.1 x 10~* Q.
It should be noted that this extrapolation is based on a one
hit mathematical model which may be invalid for this chemical.
In addition, the extrapolation pertains to Arochlor 1260 and not.
to any of the polychlorinated biphenyls which make up this
compound. It would be impossible from this limited study to
-------
single out any one of the PCBfs as the carcinogenic agent and it
should be kept in mind that they may be acting synergistically.
V. CONCLUSIONS AND RECOMMENDATIONS
Although there are considerable data on toxicitv of mixtures
of PCB's, there is a paucity of data on the pure congeners
present in these mixtures. Whether chronic toxioity is related
to the metabolism of the PCB's and their intermediates or to the
highly chlorinated stored PCB's remains to te determined.
Considerably more attention must be directed to the detect ion of
impurities in PCB's at very low concentrations.
Polychlorodibenzofuran may constitute only one of several
significant contaminating compounds responsible for PCB toxicity.
Populations at special risk—both the industrially exposed and
those heavily exposed by the ingestion of contaminated foods--
should be carefully evaluated.
Despite the current lack of evidence in the united states
that dietary PCB1s have any deleterious effects on health, there
is a growing concern with long-range effects of the contamination
of our ecosystem with these chemicals. There is an urgent need
for epidemiologic studies of exposed populations, more precise
identification of all sources of PCB contamination, and efforts
directed at the control of disposal of PCE's. Because of the
demonstrated carcinogenic potential, studies on individual
congeners, both those metabolized and those stored by man, are
urgent.
The available chronic toxicity data are summarized in Table
VI-56.
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TABLE Vt-56. Summary of Chronic
Toad.e«y Data for PCB*s
Dosage Levels and Highest if p-adverse
Duration No. of Animals per effect Level or Lowest Effect
Specie*
Mink
Mi*
of Study Grow? Minimal- effect Level Measured
6 mo.
9«6.
30
5
me/kg In diet
mg/kg in diet
lOOfjt mortality
Females failed
Reference
Aiilerich et
el., 1973
Ringer et a]
Rat
Rat
(Female)
21
1,10,100
100 mgAe ^ dlet
0,100 mg/ltg in diet 100 mg/kg
173-lSU animals/
group
(Aroclor 1260)
to produce 1972
offspring
Adverse
effects
Kiplinger et
al., 1971
Heptocellular Kimbrough et
carcinoma al., 1975
Aroclor 1260 is an animal carcinogen^
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PROPYLBENZENE
I. INTRODUCTION
Propylbenzene (1-phenylpropane) is produced in petroleum
refining and as a byproduct of cumene manufacture, it is used in
the manufacture of methylstyrene and in textile dyeing (EPA,
1975d) . It is insoluble in water (CRC Handbook of chem. E Phy. ,
1970-1971) . Two of the 10 water supplies surveyed by the EPA
(1975a) contained propylbenzene in the finished water, at 0.05
lig/liter in Miami and 0.01 ttq/liter in Cincinnati.
II. METABOLISM
Propylbenzene is probably readily absorbed from the
gastrointestinal tract and the lungs and excreted mainly in the
urine of humans (Thienes and Haley, 1972). No information on
tissue or organ storage was available. Metabolically,
propylbenzene is characterized by high stability of the benzene
nucleus (Smirnova and Stepanova, 1969). In rats, there appears
to be a dual metabolic pathway: side-chain oxidation and ring
hydroxylation, with the former preferred (Gerarde and Ahlstrom,
1966) .
III. HEALTH ASPECTS
A. Observations in Man
Propylbenzene is irritating to the mucous membranes, eyes,
nose, throat, and skin. Systemically, it causes depression of
the central nervous system, headache, anorexia, muscular
weakness, incoordination, nausea, vertigo, paresthesias, mental
confusion, and unconsciousness. Possible effects on the liver,
bone marrow, and heart are not known (Thienes and Haley, 1972).
B. Observations In Other Species
Acute effects. In one study, the Lpso was 7.5 g/kg in rats
and 5.2 g/kg in mice (Smirnova and stepanova, 1969). In another
study, the LD50 in rats was shown to be 6.01 g/kg (Jenner et al.,
1964) .
Chronic effects. In a 6-month subchronic oral study (Gerarde
and Ahlstrom, 1966), groups of 15 rabbits were fed propylbenzene
at 0.25 and 2.5 mg/kg/day. The test animals did not differ from
the controls in general appearance, body weight, organ weights,
and protein function of the liver.. There was a 7% decrease in
the red-cell count in the high-dosage group that was not
significant. Hemosiderin was deposited in the spleens of the
high-dosage animals, indicating red-cell destruction. There was
-------
50
a nonsignificant leukocyte increase in both dosage groups. .
Individual animals exhibited mild protein dystrophy of the livf r
and kidneys.
Mutagenicity. No available data.
Carcinogenicity. No available data.
Teratogenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity and long term oral toxicity ot
propylbenzene, estimates of the effects of chronic oral exposure
at low levels cannot be made with any confidence. It- is
recommended that studies to produce such information be conducted
before limits in drinking water can he established.
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STYRENE
I. INTRODUCTION
Styrene monomer is synthesized from ethylene and benzene. It
is used in the manufacture of polystyrene plastics, resins,
insulators, synthetic rubber, and protective coatings (Chem.
Diet. 1972). The Chited States production of styrene in 1973 was
over 2.56 billion pounds (USITC, 1975). Styrene is insoluble in
water. It has been detected in the finished water of three of
the 10 water supplies surveyed by the EPA, (1975a).
II. METABOLISM
In a study conducted by El Masri et al. (1958) , rabbits were
given styrene orally, and the metabolites were determined. It
was established that the main metabolite of styrene was hippuric
acid, which accounted for 30 - 40% of the oral dose. Lesser
metabolites were mandelic acid and phenylglycol, the latter being
excreted as a monoglucuronide. Only about 2% of the styrene
administered was eliminated unchanged in the expired air.
Because phenylglycol itself yields hippuric acid, mandelic acid,
and phenylglycol as metabolites, it is suggested that styrene may
undergo perhydroxylation in vivo to its intermediate,
phenylglycol. It was noted that the metabolites of styrene were
almost completely excreted 1-2 days after administration of the
single dose.
III. HEALTH ASPECTS
A. Observations In Man
Wolf et al. (1956) , in the course of conducting inhalation
studies on animals, exposed human subjects to various
concentr t: ,5ns of styrene monomer. They reported very strong
odor wit> eye and nasal irritation at 600 ppm, detectable odor
with no irritation at 60 ppm, and no detectable odor at 10 ppm
and less.
Stewart et al. (1968) exposed human volunteers to styrene
vapors at approximately 50, 100, 200, and 375 ppm for periodb or
1 - 7 h. Only at 375 ppm did the subjects experience subjective
symptoms and objective signs of transient neurolog r impairment
The vapors irritated the eyes and nose and in one subject-
produced a burning sensation of the facial skin. Neurologic
effects were manifested by inability to perform a normal mod5.fi&c
Romberg test, a decrease in the Crawford Manual Dexteri*:- co^or
and Pin Te^t score, ^nd decreased performan^f i~i the Flanniga~>
Coordination Test. Stewart et al. (1968; showed that the
of styrene exhaled after an exoo; are indr'ca d the exter of
-------
exposure. Urine hippuric acid content, however, was not a
sensitive indicator.
B. observations In other Species
Acute effects. In an acute study. Spencer et al. (1912)
exposed rats and guinea pigs to various vapor doses of the
compound. At the lowest dose (650 - 1,300), the animals
demonstrated eye and nose irritation. Styrene could be tolerated
for only 8 h at 1,300 - 2,000 ppm. The maximal tolerated time
without serious adverse effects was reduced to 1 h at 2,500 ppm;
and 10,000 ppm proved lethal in 30 - 60 m.
Chronic effects. In a study of the chronic effects of
styrene. Spencer et al. (1912) intubated rats 5 days/week for 28
days at 2.0, 1.0, 0.5, and 0.1 g/kg/day. Animals survived 0.5
g/kg, but lost weight, probably owing to gastrointestinal
irritation. The no-adverse-effect dosage was 0.1 g/kg/day. Wolf
et al. (1956) intubated rats daily, 5 days/week, for 185 days
(132 doses), at doses of 66.7, 133, 400, and 667 mg/kg/day. The
no-adverse-effect level was 133 mg/kg/day. The only dosage-
related effects at higher dosages were increased liver and kidney
weights. In the same study, rats, guinea pigs, rabbits, and
monkeys were chronically exposed to styrene by inhalation. The
no-observed-adverse-effect concentration was 650 - 1,300 ppm,
with some species variability.
Mutagenicity. No available data.
Carcinoqenicity. No available data.
Teratogenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
Styrene at high concentrations is mainly an irritant whether
ingested or inhaled. Humans have tolerated acute exposures of
200 ppm with no ill effects.
An ADI was calculated on the basis of the available chronic
toxicity data. Based on this data the ACI is 0.133 mg/kg/day.
The available chronic toxicity data and calculations are
summarized in Table VI-57.
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53
TABLE VI-57. Summary of Chronic
Toxicity Data for Styrene
Dosage Levels and Highest No-adverse
Duration Mo. of Animals per effect Level or lowest Effect
Species of Study Group Minimal-effect Level Measured Reference
Rat 28 days 0-20 g/kg/day,
intubated
Rat 185 days 0-66? mg/kg/day,
intubated
0.1 g/kg/day
133 mg/kg/day
No adverse Cpencer et al. ,
effect
No adverse Wolf et_ al. ,
effect 1956
Usinpj an uncertainty factor of 1,000, suggested no-adverse-effect level in
drinking vater is calculated as follows:
133 = 0.133 me/kg/day (ADI), 0.133 x ?0a x O.lb « 0.9 me/liter.
1,000
a
Assume average weifht of human adult = 70 kg.
^Assume average daily intake of water for man = 2 liters, and that 2O^> of total intake
is from water.
c
Test study from which to calculate suggested no-adverse effect level.
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TETRACHLOROETHYLENF
I. INTRODUCTION
Tetrachloroethylene (perchloroethylene) is used as solvent,
heat-transfer medium, and in the manufacture of fluorocarbons
(EPA, 1975d). The United States production of this compound in
1973 was over 705 million pounds (USITC, 1975) . It is insoluble
in water (CRC Handbook of Chem. 6 Phys., 1970-1971). During
chlorination of water treatment, it can be formed in small
quantities (EPA, 1975d). It has been found in the finished water
of the New Orleans area at up to 5 jjg/liter (EPA, 1974). Eight
of the 10 water utilities surveyed by the EPA (1975a) contained
tetrachloroethylene, at 0.07 - O.«l6 pg/liter.
II. METABOLISM
There have been a number of studies pertaining to the
metabolism of tetrachloroethylene in mice, rats and humans
(Yllner, 1961; Daniel, 1963; Ogata, 1971). The consensus appears
to be that most of the material is expired unchanged and that
very little (5%) is metabolized and later excreted in the urine
or feces. However, experience with similar compounds indicates
that the portion metabolized may be markedly greater at low doses
than at high doses. Up to 10% remains in the body (very likely
in the fat) after 4 days, but, to judge by these reports there is
little likelihood of cumulative toxicity.
III. HEALTH ASPECTS
A. Observations In Man
Rowe et al. (1952) showed central nervous system effects in
man from single exposures at 200 ppm, but not at 100 ppm.
B. Observations In Other Species
Acute effects. In studies of the acute effects of
tetrachloroethylene, the oral LDSO was shown to be a,000 mg/kg in
dogs and 5,000 mg/kg in rabbits (Registry of Toxic Effects of
Chemical Substances, 1975).
Chronic effects. In a chronic study, Rowe et al. (1952)
exposed groups of rats, rabbits, guinea pigs, and monkeys
repeatedly to various concentrations of tetrachloroethylene (100
- 2,500 ppm) for various periods (13 - 179 exposures in 18 - 250
days). No adverse effects were observed at 100 ppm.
Mutagenicity. No available data.
-------
55
used rabbits that inhaled chlorinated hydrocarbons at 2 mq/m3 for
3 h/day for 8-10 months. Tetrachloroethane was found to be
more harmful to total antibody formation than its pentachloro- or
dichloro- analogues.
Mutagenicity. No available data.
Carcinogenicity. No available data.
Teratoqenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity, and long term oral toxicity of
1,1,1,2-tetrachloroethane, estimates of the effects of chronic
oral exposure at low levels cannot be made with any confidence.
It is recommended that studies to produce such information be
conducted before limits in drinking water can be established.
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58
TOLUENE
I. INTRODUCTION
Toluene is formed in petrolejum refining and coal tar
distillation. It is used in the manufacture of benzene
derivatives, caprolactam, saccharin, perfumes, dyes, medicines,
solvents, TNT, and detergent and as a gasoline component (EPA,
1975d). The United States production of toluene in 1973 was over
6.8 billion pounds (OSITC, 1975). It is insoluble in water (CPC
Handbook of Chemistry and Physics, 1970-1971). six of the 10
water supplies surveyed by the EPA (1975a) contained toluene. It
has been reported that the finished water of the New Orleans area
contained toluene, at up to 11 i*g/liter (EPA 1975c) .
II. METABOLISM
In man and rabbits, Bakke and Scheline (1970) reported that
approximately 80% of a dose of toluene was excreted in the urine
as hippuric acid (benzoyl glycine), whereas most of the remainder
was exhaled (Williams, 1959). These authors also reported that
O.a - 1.1% was excreted as o- or p/-cresol. In hydrolyzed urine,
small amounts of benzyl alcohol were detected; this suggested
that this may be an intermediate in the formation of benzoic
acid.
Pretreatment of rats with phenobarbital increased the rate of
disappearance of toluene from the blood (Ikeda and ohtsuji, 1971)
and shortened the sleeping time after injection of toluene; thus,
induction of the hepatic microsomal enzyme system may stimulate
toluene metabolism.
The reports of Ogata et al. (1970, 1971) tend to show that,
at relatively low exposures to toluene, the excretion of hippuric
acid is proportional to the exposure. They also demonstrated
that, when human volunteers were exposed at up to 200 ppm, 68* of
a calculated dose was excreted as hippuric acid.
III. HEALTH ASPECTS
A. Observations In Man
All the available information on acute human exposure to
toluene suggests a narcotic effect. Benzoic acid and hippuric
acid, the major metabolites of toluene, are relatively innocuous
and have been used as a clinical measure of liver function. In
these studies, subjects are given 6 g of sodium benzoate orally,
and excretion of hippuric acid is measured over the next ft h.
Excretion over this period accounts for approximately 50% of the
ingested dose. Thus, relatively large quantities of the known
-------
major metabolites produce no known toxic effects in man. In
addition, benzoic acid is approved as an antimicrobial food
additive at 1,000 ppm.
Many reports on long-term industrial exposure to toluene are
available. Capellini and Allessio (1971) reported that 17
workers were exposed for several years to a mean atmospheric
toluene concentration of 125 ppm, without any detectable change
in blood characteristics or in liver function. Banfer (1961)
reported on studies of 889 photogravure printers and helpers
exposed for more than 3 years to variable toluene concentrations
(measured on only 1 day, maximal concentration was 400 ppm;
generally, it was 200 ppm), with no hematologic abnormalities.
Greenburg (19U2) reported on 61 workers exposed to toluene at 100
- 1,100 ppm from 2 weeks to 5 years. He reported no severe
illness, but found some evidence of mild red-cell decrease,
enlarged liver, and increased mean corpuscular hemoglobin
concentration.
Forni et al. (1971) reported that people exposed to toluene
(at approximately 200 ppm) for work periods of 3 - 15 years
showed a somewhat higher average rate of unstable chromosomal
changes and calculated breaks, but the differences were not
statistically significant.
The human exposure data suggest that some effects of narcosis
are evident at around 200 ppm. This was the threshold limit
value (TLV) suggested for control of industrial exposures from
1947 to 1971. The TLV was then lowered to 100 ppm, on the basis
of irritation to eyes and upper respiratory tract. The NIOSH
criteria document (1973) for a recommended standard for toluene
indicated that a literature search failed to confirm any clinical
or laboratory evidence of altered liver function in workers
exposed to 80 - 300 ppm for many years.
B. Observations In Other Species
Acure effects. Svirbely et al. (19H3) reported the minimal
lethal acute ir halation concentration of toluene (containing
0.01X benzene) co be 20 mg/liter (5,300 pprn> in mice for a single
8-h
j-: -; r effer-tr 'ore et al. (1955) reported that two 1o-.,o
,- -vr ~ * ~ •:: 5 3 h •'"'; ay f 6 iav 3 'week- for U months tr
-To-'- • . ,* benzene) c 2., 000 pp:< (7,5 :ng/ '. :1 • c) j
- - j-;i 2 ' -H at 2,660 ppm (10 mg/lrt er] showed s ; ns of
.:•. '--'o .1-,/si-r a j-i •-'ication, incoordinatioa, -,a.^ paTdi "--'- " t k
r ' "filters. bl.>od i. bone marrow studies yield-a normal, r^su-i.
Congestive changes were seen in lungff v-:eai t liver, ki .
spleen. Takeuchi (1969) exposed rats t; roi ene (99.
°
-------
58
200, 1,000, and 2,000 ppm for 8 h/day for 32 weeks. No
significant changes in body weight or hematologic findings were
reported.
Gerarde (1956) reported that rats given daily injections of
toluene at 1 ml/kg in olive oil for 2 weeks showed no
abnormalities with respect to peripheral blood, femoral bone
marrow, or weight of thymus or spleen. In rabbits given toluene
subcutaneously at 300 mg/kg/day for 6 weeks or 700 mg/kg/day for
9 weeks, no decrease in bone marrow function was found, as
measured by uptake of tritium-labeled thymidine, nor was there
any alteration in the formed elements of the peripheral blood.
Mutagenicity. No available data.
Carcinooenicity. No available data.
Teratoqenicity. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
Other than central nervous system depression, the inhalation
of toluene at less than 2,000 ppm has produced no adverse
effects. In addition, the major metabolite of toluene, benzoic
acid, is considered relatively nontoxic and is an approved food
additive.
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity and long-term oral toxicity of
toluene, estimates of the effects of chronic oral exposure at low
levels cannot be made with any confidence. It is recommended
that studies to produce such information be conducted before
final limits in drinking water can be established.
-------
TRICHLOROBENZENE
I. INTRODUCTION
Trichlorobenzene is produced by chlorination of
monochlorobenzene. It is used as a solvent, dielectric fluid,
lubricant, and heat-transfer medium; in polyester dyeing, and in
termite preparations (EPA, 1975d).
The United States production of 1,2,11-trichlorobenzene in
1973 was over 28 million pounds (USITC, 1975). It is insoluble
in water (CRC Handbook of Chemistry and Physics, 1970-1971).
Trichlorobenzene can be formed in small quantities during
chlorination of drinking water (EPA, I975d) . of the 10 water
supplies surveyed by the EPA (1975a), trichlorobenzene was only
detected in the finished water of Lawrence, Massachusetts.
II. METABOLISM
In metabolic studies with rabbits using each of the three
isomeric trichlorobenzenes at 0.5 g/kg, 1,2,3-trichlorobenzene
was the most rapidly metabolized, and 1,3,5-trichlorobenzene was
least rapidly metabolized. In 5 days, 62% of the 1,2,3-trichloro
isomer underwent glucuronic conjugation. The major metabolite
was 2,3,4-trichlorophenol; small amounts of 3,4,5-
trichlorophenol, 3,4,5-trichlorocatechol, and mercapturic acid
were also detected. 1,3,5-Trichlorobenzene formed practically no
ethereal sulfate or mercapturic acid, and the only phenol formed
was 2,U,6-trichlorophenol (Jondorf et al., 1955).
Along with tests on other halogenated benzenes, 1,3,5-
trichlorobenzene was administered orally to rats at 2 mg/kg, and
this chemical was found in the fat at greater co: centrations than
in liver, kidneys, heart, or blood. These studies were designed
to show the possible effects of chlorinated substances from Rhine
River water and how they might affect body burden in animal
tissues and organs (Jacobs et al., 197<4) .
III. HEALTH ASPECTS
A. Observations In Man
In one plant where benzene was chlorinated over a period of i»
years, there was no apparent serious illness, liver function
change, or alteration in blood components. One worker who
inhaled a massive amount of trichlorobenzene experienced some
hemorrhaging in the lungs (Erlicher, 1968).
-------
60
B. Observation In Other Species
effects. Acute-toxicity tests have been conducted in
rats (CFE strain) and mice (CF No. 1 strain) by oral and
percutaneous administration. The single-dose acute oral LDSO was
756 mg/kg in rats. The main signs of intoxication were decrease
in activity at a low dose and convulsions at higher doses. Death
.occurred 5 days after exposure. The single-dose acute oral LDSO
was 766 mg/kg in mice. Signs of intoxication were the same as in
rats (Brown et al., 1969).
Chronic effects. In chronic-skin-irritation studies with
rabbits and guinea pigs, trichlorobenzene was not irritating,
although some degreasing action took place after prolonged
contact. After 3 weeks of exposure, there was some skin
inflammation characterized by spongiosis and parakeratosis.
Livers of guinea pigs were found to have necrotic foci (Brown et
al., 1969). Trichlorobenzene was also evaluated for its
acnegenic potential in rabbits by applying 1,2, H- trichlorobenzene
to the ears of rabbits for 13 weeks. There was no typical
acneiform dermatitits, but there was some dermal irritation
(Powers et al. , 1 975) .
Mutagenicity. No available data.
Carcinogen icity* No available data.
Teratoqeni city. Ho available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity and long term oral toxicity of
trichlorobenzene, esimates of the effects of chonic oral exposure
at low levels cannot be made with any confidence. It is
recommended thai- studies to produce such information be conducted
before limit In d'inkinq water can be established.
-------
TRICHLOROETHYLENE
I. INTRODUCTION
Trichloroethylene (trichloroethene) is used primarily in
metal degreasing. It is also used in dry-cleaning operations, as
a solvent, in organic synthesis, and refrigerants and fumigants
(Frear, 1969). The United States production of this compound in
1973 wa& over U51 million pounds (USITC 1975).
Trichloroethylene is slightly soluble in water (CPC Handbook
of Chemistry and Physics, 1970-1971). It can be formic! during
ohlorination of water (EPAf 1975d). The 10-city survey indicated
that finished water of five supplies contained trichloroethylene,
at 0.1 - 0.": Mg/liter (EPA, 1975a) .
II. METABOLISM
Butler (1919) indicated that trichloroacetic acid,
trichloroethanol, and small amounts of chloroform and
monochloroaretic acid were the metabolic products of
tuchloroethylene. Ikeda and Ohtsuji (1972) reported that rats
excrete 5-7 times more trichloroethanol than trichloroacetic
acid after exposure to trichloroethylene. The excretion of
trichioroer.hylene and trichloroacetic acid in thp urine has been
used to some extent to measure trichloroethylene exposure.
Til. HEALTH ASPECTS
A. observations In Man
Exposure to triohloroethylene results in central nervous
system depression, incoordination, and unconsciousness, as
evidenced by its use as an anesthetic. Acute human exposures
have occurred, but have not always been clear cut.cases of
exposure to a single entity. The report of Feldman et al. (1970>
concerned a person who was exposed to trichloroethylene vapors
from an overheated degreasing unit. He experienced nausea,
vomiting, blurred vision, and numbness of the face 10 - 12 h
after exposure. The recovery of sensation in the face and motor
function of facial muscles occurred slowly over an 18-month
period. Sa-gawa et al. (1973) reported accidentrl exposure of a
young woman to vapor and mist of trichloroethylene, which
resulted in unconsciousness and a permanent residual disability
with respect to mobility. In fatal cases of acute
trichloroethylene exposure reported by Kleinfeld and Tabershav;
(1954), there was no tissue abnormality at autopsy. Based on
chronic exposure of human work populations there are no reported
problems with respect to hepatotoxicity. Both Stewart et al.
-------
(J970) and Ikeda and Imamuru (1973) reported a rather prolonged
(2 - 3 days) biologic half-life for trichloroethylene.
The NIOSH (1973) recommended the occupational exposure to
trichloroethylene at not in excess of 100 ppm as a time-weighted
average exposure for an 8 h workday.
B. Observations In Other Species
Acute eftects. The acute oral LD5O of trichloroethylene in
rat& was 4,920 mg/kg (Registry of Toxic Effects of Chem.
Substances, 1975) . Comparative studies of acute toxicity of
halogenated hydrocarbon solvents have also demonstrated that
uear-lethal doses of trichloroethylene are necessary to produce
•wild hepatic dysfunction (Klassen and Plaa, 1966) . Baker (1958)
reported severe changes in the cerebellum, particularly in the
Purkinje cell layers in dogs exposed to 3,000 ppw of
trichloroethylene vapor. The dogs were exposed from 2-8 h/day
up to 6 days.
Chronic effects. In a study of the chronic effects of
trichloroethylene, a 6-month inhalation exposure to 3,000 ppm
resulted in increased liver and kidney weights in mice and rats
(Adams et al., 1951).
Mutaqenicity. No available data.
Teratogenicity. Scnwetz et al. (1975) described the acute
exposure of mice and rats to 300 ppro, 7 h/day, on days 6 - 15 ot
gestation. No embryonal or fetal toxicity was noted, nor were
there any teratogenic effects.
Carcinociani ci ty . Trichloroethylene was tested (for
carcinogen! city by NCI (1976) in a chronic feeding study. Both
sexes of Osbome-Mendel rats and B6C3F, mice were used. Animals
v^ere exposed to two doses (MTC and 1/2 MTD) by oral gavage 5
Limes/w*ek for 78 weeks. All animals were then kept until
terminal sacrifice at 110 weeks. The doses used were as follows:
1097 and 519 mq/kg for both male and female rats and 2,339 and
1,169 ing/ kg for male mice and" 1,739 and 869 mg/kg for female
i.tice. Significant dose related hepatocellular carcinoma was seen
in born male and female mice, but the rats were quite resistant
to the carcinogenic effects of trichloroethylene.
xv. CARCINOGENIC RISK ESTIMATES
The statistical assessment of human cancer risk associated
with trichloroethylane in drinking water is based on the results
of a care? ncgenesis bioassay experiment with animals (NCI, 1976).
Trichloroeth 'lene was dissolved in corn oil and administered by
-------
gavage to male aud female B6C3Ft mice 5 days/week for 78 weeks.
The surviving mice were sacrificed at 90 weeks, and a complete
necropsy and microscopic evaluation of all animals were
conducted. Highly significant differences in the incidence of
hepatocellular carcinomas were found between treated and control
mice of both sexes.
The available sets of dose response data were individually
considered as described in the risk section in the chapter on
margin of safety. Each set of dose response data was used tc
statistically estimate both the lifetime risk and an upper 95%
confidence bound on the lifetime risk at the low dose Iev3l.
These estimates are of lifetime human risks and have teen
corrected for species conversion on a dose'surface -rea basis.
The risk estimates are expressed as a probability of cancer after
a lifetime consumption o^ 1 liter of water/day containing Q ppb
of the compound of interest. For example, a risk of 1x10~6 Q
implies a lifetime probability of 2::10~s of cancer if 2
liters/day were consumed and the concentration of the carcinogen
was 10 ppb (i.e., Q=10). This means that at a concentration of
10 ppb during a lifetime of exposure this compound would be
expected J:o produce one excess case of cancer for every 50,000
persons exposed. If the population of the United States is taken
to be 22. million people this translates into 4,400 excess
lifetime deaths from cancer or 62.8/year. Since several data
sets are typically available the range of the low-dose risk
estimates are reported. For trichloroethylane at a concentration
of 1 jjg/liter ^Q=1) the estimated risk for mar would be 1.1 - 36
X 10~7 Q. The upper 95% confidence estimate of risk at the same
concentration is 1.6 - 93 X 10-7 Q.
It should be emphasized that these extrapolations are based
on a number of unverifiable assumptions: extrapolation from high
exposure to low exposure in mice, en the basis of a multistage
mathematical model; extrapolation from mouse to man, on the basis
of the surface-area rule; and extrapolation from gavage exposure
x:o oral exposure assumed equal. These estimated human risks
should be taken as crude estimates at best.
IV. CONCLUSIONS AND RECOMMENDATIONS
It is concluded that trichloroethylene has low toxicity, both
acute and chronic. Only after high acute accidental exposures
have effects been reported in humans. These have been related to
the depressant effect _>n the central nervous system. No fetal
toxicity or leratoganic effects have been reported. Carcinogenic
bioassay demonstrated hepatocellular carcinoma in one strain of
mice. The chronic toxicity data are summarised in Table VT-58.
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64
TABLE VI-58. Summary of Chronic
Toxic ity Data for Triehloroettylene
Dosage Levels and Highest Ho-adverse
Duration No. of Animals per effect Level or Lowest Effect
Soecies of Study Group Minimal-effect Lovel Measured Reference
Mouse 78 «ks. 0,1169, 2339 Ho9 mg/kg/day Hepatomas NCI, 19?6
(male) mg/kg/day, gavage
20-50 animals/group
Mouse 78wks. 0,869,1739 869 mg/kg/^y Hepatomas HCI, 197*
mg/kg/day, gavage
20-50 animals/group
compound Is an animal carcinogen}
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1,1,2-TRICHLOROETHflNE
I. INTRODUCTION
1,1,2-Trichloroethane (Vinyl trichloride) is usfd as s
for fats, oils, waxes, and resins and in the synth^sir of organic
chemicals (EPA, 1975d). It is insoluble in wat^-r (CP' Handbook of
Chem. & Phys., 1970-1971). During chlorir.ation water treatment,
1,1,2-trichloroethane can be formed in small qu-int-i*- if T, (F.^A,
1975d). Of the 10 water supplies surveyed by th^ FPft (1975a),
only the finished water of Miami contained 1,1,2--*-richloro^thane.,
It has also been found in the finished water of the New Orleans
area, at less than 0.1 to 8.5 pg/liter (FPA, 1975c).
II. METABOLISM
Trichloroethane is excreted primarily by the lungs, with so^ie
elimination via the kidneys (Browning, 1965). The major
metabolite in the mouse of this compound is chloroacetic acid;
minor metabolites are 2,2-dichloroethanol, 2,2,2-
trichloroethanol, oxalic acid, and trichoroacotic acid (Yllner,
1971a) . In vitro, the compound is dechlorinater1 hy a
reconstituted rat liver microsomal mixed-function oxidase system
(Gandolfi and Van Dyke, 1973).
III. HEALTH ASPECTS
A. Observations In Man
The ad-verse health aspects of t!r's compound in man hav<= not
been examined. No toxic effects have been recorded in
association with its applications in industrial soTverits
(Browning, 1965).
B. Observations In Other Species
Acute effects. LD50's of 1,1 ,2-trichloroe+ hanr- w^r«
calculated to be: 0.58 (0.47 - 0.71) and l.ia g/Kg orally in
rats (Smyth et al., 1969; Union Carbide Corp., 1968); 0.35 (0.28
- 0.<14) ml/kg and 3.7 (3.0 - U. 7) ir.M/kg intraperitoncally in male
and female Swiss-Webster mice, respectively (Klaassen and ^laa,
1966; Gehring, 1968); and 3.73 (3.30 - 4.2!) ml/kg dermally in
rabbits (Smyth et al., 1569; Toxicology Information Bulletin,
1968) .
The hepatotoxicity of trichloroetiiatie has been extensively
examined in a variety of experimental animals. Cellular-
infiltration, vacuolation of hepatocytes, ircre .ced yer.um
g.lutamic pruvic transaminase (EGPT) and prolonqetl rr^terition ."
BSP (bromsulphalein) h.^vo beer-, obe^-rvr-d in studies 'vith 'liio
-------
(Klaassen and Plaa, 1966). SGPT increases and the threshold
doses have also been shown to be potentiated by ir,opropyl alcohol
and acetone in mice treated with 1,1,2-trichloroethanr at 0.05 -
0.1U ml/kg (Traiger and Plaa, 197U). In dogs, mild centrilobular
necrosis, slight subcapsular necrosis, and vacuolation of the
centrilobular hepatocytes have been observed, in combination with
increased SGPT (Klaassen and Plaa, 1967).
In studies that sought to examine the nephrotcxicity of
trichloroethane, the presence of hyaline droplc-vs, nuclear
pycnosis, hydropic degeneration, increased eopinophilia, tubular
necrosis with karyolysis, and loss of epithelium of convoluted
tubules in mice have been reported, in combination wi4h a
decrease in jj-aminohippuric acid concentration and ,*lt*red
urinary PSP (phenolsulfonphthalein) excretion (Kiaassr-n and Plaa,
1966). In dogs, tubular necrosis has been observed af^er
exposure to trichloroethane, but it appeared to be less severe
than that seen in mice; urinary PSP excretion was also modified
in dogs (Klaassen and Plaa, 1967).
Chronic effects. No available data.
Mutagenicity. No available data.
Carcinogenicity. There are some indications th^t responses
to trichloroethane are comparable both qualitatively /»n--i
guantitatively with those to carbon tetrachloride (brownin;,
1965) .
Teratogeni,city. No available data.
IV. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity and long term oral toxicity of
1,1,2-trichloroethane, estimates of the effects of chronic oral
exposure at low levels cannot be made with any confidence. It is
recommended that studies to produce such information br conducted
before limits in drinking water can he established.
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TRICHLOROFLUOROMETHANF
I. INTRODUCTION
Trichlorofluoromethane (Freon 11) is used in the manufacture
of aerosol sprays, refrigerants, blowing agents, and cleaning
compounds and in fire extinguishers (EPA, 1975d). The United
States production of this compound in 1973 was over 333 million
pounds (USITC, 1975). It has been reported that the finished
water of Washington, D.C., contained less than 1 pg/liter of
trichlorofluoromethane (Scheiman et al., 1974).
II. METABOLISM
When trichlorofluoromethane was inhaled by humans, recovery
of the intact compound in exhaled air was 79 - 99% and in urine,
0.07 - 0.09S, and metabolites amounted to 0.2% or less (Mergner
et al., 1975). Terrill (1974) demonstrated that absoprtion of a
fluorocarbon, F115, in dogs was 35-48 times greater by
inhalation than by oral administration. Charlesworth (1975)
indicc ted that the main factor affecting the fate of
flucre'Carbons is the body fat, where they are concentrated and
slowly released into the blood at concentrations that should not
cause any risk of cardiac sensitization. Blake and Mergner
(1974) showed that inhalation of 1*C labeled Freon 11 by dogs
resulted in complete recovery in exhaled air (101.8%) in 1 h, and
recovery from urine of only .0095%, and no evidence of
biotransformation. However, Niazi and Chiou (1975), who
administered Freon 11 intravenously in dogs, demonstrated that,
although the compound is rapidly eliminated from the bloodstream,
it is then eliminated via three compartments with half-lives of
3.2, 16, and 93 m.
III. HEALTH ASPECTS
A. observations In Man
By inhalation, large, acute doses have resulted in cardiac
sensitization (ar r.\ ythmia) or bronchial constriction leading to
death (Dollery et e_l., 1970). The threshold limit value (ACGIU,
1967) is 1,000 ppm*, or 5,600 mg/m^.
B. Observations In Other Species
Acute £?"f^£t_s. Slater (1S65) gave a single oral dose of 2.5
g/kg~~t3 rats and r-ported no liver pathology. Lester and
Greeriberg (1950) reported that inhalation by rats of aerosol
containing 6% Freou 11 resulted in loss of postural reflex, 8%
resulted in loss of righting reflex, 9% resulted in
unconsciousness, and 10% wa^ It-thai. viro that inhal >o 10%
-------
developed cardiac arrhythmia (Aviado and Belej, 1975) ; dogs that
inhaled 2.5% had decreased myocardial function, including cardiac
output (Aviado and Belej, 1975); and monkeys that inhaled 5%
developed tachycardia and hypotension (Belej and Aviado, 1973).
Chronic effects. Kudo et al. (1971) reported that mice given
oral doses of 15, 55, and 220 ing/kg/day for a month showed only
slight effects on food utilization.
Mutaqenicity. No available data.
Carcinogenicity. In a study by Epstein et al. (1967) mice
given 0.1 ml of 10% solution solution at 1 and 7 days of age and
0.2 ml at 11 and 21 days of age were observed for a year. No
evidence of a carcinogenic effect of Freon 11 was found.
Teratoqenicity. Paulet et al. (197U) reported that
inhalation at 200,000 ppm of a 9:1 mixture of Freon 12 and Freon
11 by rats on days 4 - 16 of gestation and rabbits on days 5-20
of gestation did not induce any embryotoxic or teratogenic
effects.
IV. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the mutagericity,
carcinogenicity, and long term cral toxicity of
trichlorofluoromethane, estimates of the effects of chronrc oral
exposure at low levels cannot be made with any conr deice. It is
recommended that studies to produce such information be conducted
before limits in drinking water can be established.
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VINYL CHLORIDE
I. INTRODUCTION
Vinyl chloride (chloroethene) monomer is not known to ••:>;. oui
in nature. It is commercially synthesized by the haloo-n^': ? o,,
ethylene. In the United States, the vinyl chloride monon-'-r j-~
used primarily in the production of polyvinyl chloride rosin;
the building and construction industries. Because ir has bot ,«
confirmed that vinyl chloride monomer is a human jr;.i anirra.l
carcinogen, the sale of propellents and all aerosols containing
it was banned in 197U (EPA, 1971; United States < jnsurne^ ProchK
Safety Commission, 197U). The occupational standard for
atmospheric vinyl chloride in the United States is 1 ppm (2.S6
mg/m3) or less for 8 h/day and 5 days/week The unired States
production of vinyl chloride in 1973 was 5,35 LA Dion pounds
(OSITC, 1975).
Vinyl chloride monomer is slightly soluble in wat^r ( <0.1i'i
by weight at 25°C) (CRC Handbook of Chemistry and Physics e 1970-
1971) , Results of the 10-city survey (EFA, 1975a) indicate that
vinyl chloride was present in the finished water of Miami, ar 5.
and Philadelphia, at 0.27 pg/liter.
II. METABOLISM
After inhalation of 14C- vinyl chloride by rats, 2 - I/"*- oi
-he (10- or 1,000-ppm ppm) dose was eliminated as vinyl chloride
in the expired air within 72 h. The 10-ppn expor-.ure produced tr •
higher urinary excretion and lower expired amount . Pul.nonary
excretion was fast and followed first-order kinetico, but thf
slower urinary excretion of vinyl chloride metabolites followed
biphasic elimination pattern. Three urinary metabolites have
been detected: N-acetyl-S- (2-hydroxyethyl) cysteine ,
thiodiglycolic acid, and an unidentified substance (McGowan et
al. , 1975) .
Oral doses of 0.05 - 1.0 mg/kg in rats yielded similar
information. The pulmonary excretion was monophasic at these
doses, and the urinary metabolites are the same. At an oral dos
of 100 mg/kg, the pulmonary excretion is biphasic and a greater
percentage of the administered dose is expired as vinyl chloride
-67%, compared with 1 or 2% at the lower doce.
The above data all indicate a dose-dependent fate of vinyl
chloride after inhalation or oral administration in rats. The
primary mechanism of detoxification of vinyl chloride or its
reactive metabolites involves conjugation with hepatic
glutathione. The glutathione conjugates are then subject ^o
-------
hydrolysis, yielding the cysteine conjugates fourd in th$ urine.
This is consistent with the observed decrease in hepatic
nonprotein sulfhydryl groups in rats exposed to vinyl chloride
(Hefner et al. , 1975) .
III. HEALTH ASPECTS
A. Observations In Man
In studies of the acute effects of vinyl chloride in man, it
has been shown to produce central nervous system dysfunction,
sympathetic-sensory polyneuritis, and organic disorders of the
brain (Smirnova and Granik, 1970). In a series of studies on
workers in the polyvinyl chloride industry, scleroma-like skin
alterations, Raynaud's syndrome, and acroosteolysis were observed
(Juc>he and Lange, 1972; Juehe et al. , 197U; Berk et al. , 1975;
Martateller et al., 1975).
To date, 43 cases of hepatic angiosarcoma have been diagnosed
in industrial vinyl chloride workers around the world. All
authenticated cases were found in workers engaged in closed-in
plants handling very large quantities of liquefied vinyl chloride
under pressure (Anon., 1974; Makk et al., 1976) . Exposure
concentrations were high, probably ranging from 1,000 ppm to
several thousands ppm.
Lesions of the skin, bones, liver, spleen, and lungs have
also been reported after chronic exposure to the compound (Popper
and Thomas, 1975; Gedigk et al., 1975; Thomas and Popoer, 1975.
B. Observations In Other Species
Acute effects. Because of the physical properties of vinyl
chloride, the effects of oral exposure to it have not been
examined. With respect to inhalation toxicity, vinyl chloride
has been shown to produce lung congestion and some hemorrhagina,
blood-clotting difficulties, and congestion of liver and kidneys
in laboratory animals (Mastromatteo et al., 1960). After 2 h at.
5% vinyl chloride, rats showed moderate intoxication; 2 h at 15%
provoked respiratory failure (Iester et al., 1963) .
Mutaqenicity. In a study Iry Malaveille et al. (1975) ,
exposure of Salmonella typhimurium strains TA1530, TA1535, and G-
16 to vinyl chloride increased the number of his
revertants/plate 16, 12 or 5 times over the spontaneous mutation
rate. The mutagenic response for TA1530 strain was increased
when S-9 liver fractions from humans, rats, or mice were added.
Exposure of s.^ tvphimurium to vinyl chloride gas produced no
mutagenic effect without microsomal activation (Pannug et al.,
1974).
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Carcinogenic!ty. In a study to determine the carcinogenic
effects of vinyl chloride inhalation. Viola (1970a,b) and Viola
et al., (1971) reported that 30,000 ppm, H h/iay, 5 days/week,
for 12 months produced tumors of lungs, skin, and bones in wistar
rats. Along the same lines, 250-10,000 ppmp 4 h/day, 5
days/week, for 12 months was reported by Maltoni and I.efemine
(1974a,b' to increase the incidence of cancer in rats. Zymbal
gland carcinoma, angiosarcoma, and nephroblastoma were most
prominent. Latency for the development of these cancers ranger!
from 59 to 83 weeks. Ir another study., in which lower
concentrations (50 ppm) were used, a marked change in ^ie latency
for finding tumors indicated the possibility of a '.hreshold for
induction (Maltoni and Lefemine, 1975) .
Teratogenicity. Vinyl chloride, was administered for 7 h/day
on d^ys 6 - 18 of gestation in mice, rats, and rabbet:-. It was
concluded that, although maternal toxicity was observed, vinyl
chloride alone did not cause significant embryonal or fetal
toxicity and was not teratogenic in any of the species at the
concentrations tested (John et al., 1975).
IV. CARCINOGENIC RISK ESTIMATES
In a recent study by Maltoni et al. (1975), rats were given
vinyl chloride in olive oil by gavage fou*: or five ti:
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IV, CONCLUSIONS AND RECOMMENDATIONS
Vinyl chloride has acute and chronic toxic effects in animals
and man. In addition to its chronic toxicity, it has been
clearly shown to be a carcinogen in animals and man, with dose-
and time-related properties, and to be a mutagen in in vitro
systems. Its carcinogenic property has been demonstrated by oral
administration. This route is more effective (efficient) in
producing the characteristic tumor, angiosarcoma, than is loading
the atmosphere with similar amounts of vapor. In animal studies,
vinyl chloride has induced a wide variety of tumors, in addition
to the characteristic and otherwise rare angiosarcoma. The
available chronic toxicity data are summarized i;i Table VI-59.
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TABLE VI-59. Summary of Chronic
Toxtcity Data for Vinyl Chloride
Dosage Level* and Highest Mo-adverse
Duration Mb. of Aolaals per effect Level or lowest Eff act
Species of Study Group Minimal-effect Level Measured
Reference
Rat
Bat
12
12
0,3.33,16.65,
50 •g/kg/day
30,000 ppm, Uh/day
5
16.65 ng/kg/day
Tumors of
pvin and
bones
Angio-
aarcomas
Viola, 1970a,b
Viola et al.,
1971
Maltoni et el.,
1975
(Thi* compound is an animal and huaan carcinogen.)
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XYLFNES
I. INTRODUCTION
Xylene (dimethyIbensene) is formed in petroleum, coal tar,
and coal •_• s distillation. It is used in aviation gasolines, in
rubber cen -its, in the manufacture of solvents e»nd protective
coatings, and in the synthesis of organic chemicals (i-PA, 1975d).
The United States production of xylcne in 1973 was ov^r 5.94
billion pounds (USiTC, 1975). Xylene is insoluble in water (CPC
Handbook of Chem. 6 Phys,, 1970-1971). The finished water of the
Now Orleans area (KPA, 1975c) contained xylcne at a. 1 pg/liter.
II. METABOLISM
Oxidation of xylene to phi'r.olic rnetaLolit«>s has b« en reported
by a number of investigators, including Eakke and .Sohr-line
(1970). A dosage of 100 mg/kg in rats gave the following
results: o-xylene metabolized to 3,t»-ditnethylphonol (0.1% of
dose) and 2,3 dimethylphenol (0.03% of dose); m-xylene
metabolized to 2,1-fAo'ehylphonol (0.9% of dose); p_-xyU-ne
metabolized to 2,5-diinethylphenol (1.0% of dose). 2-'-M-thylbenzyl
alcohol was also reported as a metabolite of o-xylcne. In man,
Ogata et al_. (1970) repotted that 72% of at--orbi%d jr-xylone was
excreted as m-methylhippuric acid within 18 h.
III. ,fhALTH ASPECTS
A. observations In Man
Caipenter et al. (1975) cxix>sed human volunteers to xylene at
t*60, 1,000, and~2,000 niy/w' (approximately 100, ?25, and U50 ppm)
for 15 m. All volunteers detected the odor, and several exported
olfactory fatigue and eye irritation at tie higher
concentrations. Morley et al. (1970) repotted an r-xposure of
thxce painters to xylcne at""an estji-iated 10,000 ppm. Tv/o of the
three were in this atmosphere for approximately 18 h. One died,
with evidence of severe lung congestion and intra--alveolar
hemorrhage; the two sutvivors experienced confusion for some time
after xecovery, had impairment of renal function with recovery at
approximately 2 weeks, and nay also have had minimal liver
damage.
The NIOSH (1975) recoi«mc iidc-d a time -weighted avr-cage r-xposure
not to exceed 100 ppm of xylene for a 10 h workday, HO h
workweek.
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75
B. Observations In Other Species
Acute effects. The acute oral LD50 in rats, as reported by
Wolf et al. (1956), was 4.3 g/kg. Inhalation studies reported by
Lazarev (1929) indicated lethal effects in mice exposed to o-
xylene at 30 mg/liter (6,900 ppm) , m-xylene at 50 mg/liter
(11,500 ppm, or g-xylene at 15 - 35 mg/liter (3,450 - 8,050 ppm).
Cameron et al. (1938) reported some deaths in mice exposed to the
various isomers at 2,000 - 1,000 ppm. Hine and Zuidema (197o)
reported the xylenes to be moderately irritating to the skin of
animals. Batchelor (1925) exposed rats to xylene x'apor for 18 -
20 h/day. At 1,600 ppm, two of four rats died within 4 days.
Initial signs were incoordination and irritation of the mucous
membranes. The white-cell count was decreased after t days of
exposure. Four rats exposed to 980 ppm for 7 days had
hyperplastic bone marrow and spleen, with kidney congestion. One
animal had a 32% reduction in white cells. One of eight rats
exposed to 620 ppm for 7 days had a ^0% reduction in white-cell
count.
Subchronic and chronic effect?. Siryth and Smyth (1928)
exposed guinea pigs to xylene at 300 ppm for 4 h/day, 6 days/week
for 2 months. Slight liver and lung effects were reported at
necropsy. Speck and Moeschlin (1968) found no adverse effects on
the hematopoietic system after subcutaneous administration at 300
mg/kg/day for 6 weeks or 700 mg/kg/day for 9 weeks. The authors
suggested that other reports of myelotoxicity of xylene are
probably related to benzene contamination. Fabre (1960) reported
that rabbits exposed to benzene-free xylene (at 5 mg/liter, or
1,150 ppm) for 40 - 55 days had decreased red and white-cell
counts. Carpenter et al. (1975) exposed rats and dogs to o-
xylene at 805, 460, or 175 ppm (3.5, 2.0, or 0.77 mg/liter) for 6
h/dayr 5 days/week, for 13 weeks. No gross or microscopic
lesions were reported, and all hematologic characteristics were
comparable with those of control rats.
Mutagenicity. No available data.
Carcinogenicity. No available data.
Teratogenicity. Xylene has been reported to produce
developmental defects in chicken embryos (Kucera, 1968).
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75
IV. CONCLUSIONS AND RECOMMENDATIONS
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity, and long term oral toxicity of
Xylene, estimates of the effects of chronic oral exposure at low
levels cannot be made with any confidence. It is recommended
that studies to produce such information be conducted before
final limits in drinking water can be established.
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77
B. INSECTICIDES
1. CHLORINATED HYDROCARBONS
CYCLODIENES; ALDRIN, PIELDRIN, ENDRIN^
CHLORDANE, HEPTACHLORf AND HEPTACHLOR EPOXIDE
I. INTRODUCTION
The cyclodiene insecticides are all derivatives of
hexachlorocyclopentadiane produced by the Diels-Alder, or diene,
reaction. Their discovery and development date from the
synthesis of chlordane by Julius Hyman in 194*» (U.S. Pats.
2,509,160 and 2,606r910). Perhaps 600 million pounds of these
highly chlorinated, cyclic organic compounds have been dispersed
into the soil, air, water, and food of the United States during
the last 30 years. Little is certain about the degradation and
fate of these compounds; however, traces of them and their stable
epoxide oxidation products are ubiquitous in the environment and
are heavily bioconcentrated in the lipids of terrestrial and
aquatic wildlife, humans, and foods, especially animal fats and
milk.
The cyclodienes have been used principally as preemergence
soil insecticides for the control of corn rootworms, wireworms,
c itworms, etc.; as seed treatments; as soil poisons for control
r termites and ants; and on cotton for the control of the boll
^evil and bollworms.
Aldrin, or 1,2,3,4,10,10-hexachloro-1,4,la,5,8,8a-hexahydro-
endo-1, 4-exo-5,8-dimethanonaphthalene, is soluble in water at
0.027 ppm at 25C (Gunther et al., 1968).
Dieldrin, or 6,7-epoxy aldrin, is soluble in water at 0.25
ppm at 25°C (Gunther et al., 1968).
Endrin, or 1,2,3,4,10,10-hexachloro-6,7-epoxy-
1,4, 4a,5,6,7,8,8a-octahydro-endo-1,4-endo-5,8-
dimethanonaphthalene, is soluble in water at 0.25 ppm at 25°C
(Gunther et al., 1968). Endrin is produced by condensing
hexachlorocyclopentadiene with vinyl chloride to produce
heptachlorbicyclo-(2.2.1)-2-heptene. This is condensed with
eye1opentadiene to form isodrin and that is oxidized to the 6,7-
epoxide with peracetic or perbenzoic acid (Brooks 1973).
Chlordane, or 1,2,a ,5,6,7,8,8-octachloro-2,3,3a,4,7,7a-
hexahydro-4,7-niethanoindene, is a viscous amber liquid soluble in
water at about 0.009 ppm at 25°C. Chlordane is manufactured by
condensing hexachlorocyclopendadiene with cyclopentadiene to form
chlordene and chlorinating the latter to approximate C10H6C18.
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70
The technical material contains about 60-75% of the cis-(m.p.
106.5-108°), and trans-(m. p. 104.5-106°) isomers together with
unreacted chlordene and isomers of the C10H5C17 product
Heptachlor (Brooks 1973).
Heptachlor, or 1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-
tetrahydro-4, 7-methanoindene, is soluble in water at about 0.056
ppm at 25°C (Park and Bruce 1968). Heptachlor is produced from
Chlordene by chlorination with sulfuryl chloride (Brooks 1973).
Heptachlor epoxider or 1,4,5,6,7,8,8-heptachloro-2,3-epoxy-
3a, 4,7,7a-tetrahydro-4,7-methanoindene, is soluble in water at
0.350 ppm (Park and Bruce 1968).
Domestic production in 1971 estimates are (MAS, 1975):
Chlordane, 25 million pounds; Aldrin, 10 million pounds;
Heptachlor 6 million pounds; Dieldrin, less than 1 million
pounds; and Endrin, less than 1 million pounds. Because of their
environmental persistence and carcinogenic behavior in laboratory
animals, Aldrin and Dieldrin were banned by the FPA on October 1,
1974, and Chlordane and Heptachlor registrations for agricultural
crops were suspended on April 1, 1976.
Because of their persistence the cyclodienes and their
epoxides—viz., Dieldrin, Heptachlor epoxide, and probably
Oxyc'ilordane—are found in surface waters virtually everywhere.
In a extensive 1958-1965 survey of the rivers of the United
Sta_^s, Breidenbach et al. (1967) found the following average
concentrations of the cyclodienes:
Aldrin, <0.001-0.006 ppb
Dieldrin, 0.08-0.122 ppb
Endrin, 0.008-0.214 ppb
Heptachlor, 0.0-0.0031 ppb
Heptachlor epoxide, <0.001-0.008 ppb
DDT, 0.008-0.144 ppb
The highest concentrations were generally found in the lower
Mississippi basin. In 1964, 74% of the grab samples were
positive for: Dieldrin, 46% for Endrin, 10% for Aldrin, 17% for
Heptachlor, and 25% for Heptachlor epoxide. In comparison, 44%
^re positive for DDT and 39% for DDE.
More than 500 grab samples of finished drinking water and
related raw water from the Mississippi and Missouri Rivers were
analyzed by Schafer et al. (1969). More than 40% of the
finished-water samples contained Dieldrin at up to 0.25 ppb, more
than 30% contained Endrin, and 20% contained Chlordane at up to
0.5 ppb. Aldrin and Heptachlor were found occasionally.
-------
An extensive investigation of surface, subsurface, and
finished water in Iowa (Richard et al., 1974) showed Dieldrin
present at the following concentrations:
S. Skunk River 2-76 ppt
Indian Creek 4-30 ppt
Des Moines River 2-12 ppt
Raccoon River 1-12 ppt
Red Rock Reservoir 3-36 ppt
Rothbun Reservoir 2-22 ppt
Cedar Rapids(surface) 42 ppt
Iowa River 22 ppt
Mississippi River <0.5-7 ppt
Finished water:
Davenport 2 ppt
Iowa City 5 ppt
Des Moines 0.4-2 ppt
It was concluded that water treatment plants were not removing
substantial amounts of pesticides from raw water, *ven by
filtration through activated-carbon beds.
The New Orleans water supply contained Dieldrin at 0.05-0.07
ppb (50-70 ppt) and Endrin at 0.004 ppb (USEPA, 1974a). The 10-
city drinking-water survey (USEPA, 1975J) found Dieldrin at 1-2
Pft in drinking water of Miami, Seattle, Ottumwa (Iowa), and
C- jinnati. Other cyclodienes identified in U.S. drinking water
i..eluded Aldrin, Chlordane, Chlordene, Endrin (80 ppt) ,
Heptachlor, and Heptachlor epoxide.
Standards have been proposed for the maximal permissible
•concentrations of the cyclodienes in finished water (Schafer et
al., 1969). Concentrations suggested in 1965-1966 and based on
those of the Subcommittee on Toxicology in 1965 were: Aldrin,
32.0 ppt.; Dieldrin, 18.0 ppb; Endrin, 1.0 ppb; Heptachlor, 78.0
ppb; Heptachlor epoxide, 18.0 ppb; and Chlordane, 52 ppb. The
suggested DDT-T (DDT, DDE, and DDD combined) concentration was 42
ppb. These were drastically lowered in a 1967 recommendation
(Ettinger and Mount, 1967) based on maximal reasonable stream
allowances to: Aldrin, 0.25 ppb; Dieldrin, 0.25 ppb; Endrin,
0.1 ppb; Heptachlor, 1.0 ppb; Heptachlor epoxide, 1.0 ppb; and
Chlordane, 0.15 ppb. The DDT-T allowance was 0.5 ppb.
The U.S. Public Health Service Advisory Committee recommended
the following drinking-water standards in 19b8 (Mrak, 1969):
Aldrin, 17 ppb; Dieldrin, 17 ppb; Endrin, 1 ppt; Heptachlor, 18
ppb; and Heptachlor epoxide, 18 ppb.
The EPA has set an interim standard for Endrin in finished
water for 0.0002 mg/liter (USEPA, 1975i).
-------
30
Residues In Food. The persistent organoehlorine cyclodienes are
present everywhere in the environment, are readily biomagnified
through food chains, and are common trace contaminants of human
food. Market Basket Surveys of the U.S. diet, collected in five
major U.S. cities and designed to simulate the diet of a 16 - 19-
year-old male, have produced results summarized in Table VI-14
(HAS, 1975) .
-------
8!
TABLE VI-14: Pesticides in Food
Daily Die-tary Intake, mq.
Pesticides
Aldrin
Dieldrin
Endrin
Heptachlor
Heptachlor
epoxide
1965
0.001
0.005
T
T
0.002
1966
0.002
0.007
T
0.003
1967
0.001
0.001
T
T
0.001
1968
T*
0.004
0.001
T
0.002
1969
T
0.005
T
T
0.002
1970
T
0.005
T
T
0.001
6- Year
Average
0.001
0.005
0.001
T
0.002
*T = trace.
-------
The combined residues for Aldrin and Dieldrin are very close
to the FAO/WHO acceptable daily intake (ADI) which is 0.0001
mg/kg/day for Aldrin and Dieldrin, vs. 0.00013 mg/kg/day in 1966.
For Heptachlor and Heptachlor epoxide, the FAO/WHO ADI is 0.0005
mg/kg/day, vs. 0.00005 ng/kg/day in 1966 (Mrak, 1969) . It
should be pointed out that recent studies showing increases in
mouse hepatomas at the lowest dosages fed—i.e., 0.1 ppm
demonstrated that no-adverse-effect level for Aldrin and Dieldrin
has never been determined and that the ADI is therefore too high.
Cyclodienes in milk. Residues of the cyclodienes in milk are
particularly nigh because of the ingestion of these insecticides
with forage. Dieldrin has the highest retention time of all
pesticides in milk, approximately 100 days (Mrak 1969). For
example, analogues of 1971 milk samples from 12 grade B dairy
farms in an intensive grain-producing area of northwestern
Illinois showed combined Aldrin and Dieldrin concentrations in
butterfat of 0.131* - 0.5560 ppm (average 0.2921). There was a
definite correlation between the overall Dieldrin soil residue on
each farm (0.01 Oil - 0.3859 ppm) and the concentration in the milk
(Moore et al., 1973). Consumption of this milk (composite
Dieldrin concentration 0.22 ppm) by a 5-kg infant at 500 g/day
would provide a daily Dieldrin intake of approximately 0.75
Mg/kg, or 7.5 times the FAO/WHO AEI.
The general concentrations of organochlorine insecticides in
Illinois milk in 1971-1973 are shown in Table VI-15 (Moore,
197 .
-------
TABLE VI-15
Organochlorine Insecticides
Concentration in Illinois Milk, orm
Insecticide
Chlordane
DDT
Dieldrin
Heptachlor
Lindane
1971
0.02
0.05
0.08
0.03
T*
1972
0.04
0.02
0.04
0.03
0.02
1973
0.06
0.03
0.08
0.05
0.03
Average
0.05
0.03
0.07
0.05
0.02
*T = trace.
Of 200 samples analyzed, 87% were positive for Chlordane, 92%
for DDT, 94% for Dieldrin, 93% for Heptachlor, and 81% for
Lindane (Moore, 1975).
-------
W
Food chain effects. The cyclodiene insecticides—especially
the epoxides Dieldrin, Heptachlor epoxide, and Oxychlordane—are
very stable, both environmentally and biologically, and have high
lipid-water partition coefficients. Thus, they pass through food
chains and undergo biologic magnification (Lu et al. r 1975;
Me teaIf et al., 1973).
These factors account for the bioaccumulation of these
persistent products in human adipose tissue. The values shown in
Table VT-16 indicate the average amounts found in fiscal 1970-
1971 in over 1,400 bioassays of D.s. human fatty tissues (NAS,
1975) .
-------
TABLE VI-16: Pesticides in Fatty Tissue
Concentration, ppm
Insecticide 1970 1971 1972 1973
Dieldrin 0.27 0.29 0.2U 0.2* 0.20
Heptachlor epoxide 0.17 0.12 0.12 0.12 0.10
Oxychlordane — — 0.15 0.15 0.15
DDT-T 11.65 11.55 9.91 8.91 7.83
-------
The presence of Oxychlordane was first discovered in 1972.
The decreasing amounts of DDT-T clearly reflect the banning of
this compound.
The human is at the top of the food pyramid; thus, persistent
pesticide residues, such as those of the cyclodienes, are
excreted in human milk; see Table VI*-17 (Curley and Kimbrough,
1969). Recent unpublished studies have also identified
oxychlordane.
-------
TABLE VI-17: Pesticides in Human Milk
Concentration, ppct
Insecticide »ean range
Dieldrin 0.0073 0.0029-0.0146
Heptachlor epoxide 0.0027 <0.0001-0.0044
DDT-T 0.0027 0.0404-0.1563
-------
Dieldrin provides a graphic example of the propensity to
persist in food chains and to accumulate in lipid tissues.
Gannon et al. (1959) demonstrated that Dieldrin fed to chickens
was stored in body fat to very much higher concentrations than
when fed to steers, hogs, and lambs. For example, Dieldrin fed
at 0.1 ppm was stored at *. 1 ppm, and that fed at 0.75 ppm was
stored at 35.7 ppm. However, it was not until 1971 that it was
demonstrated that as many as 20 million chickens in Mississippi
fed on waste food stocks of soybean oil that had been processed
on soybeans grown in Aldrin-treated soil containing illegal
residues of Dieldrin (generally at 0.01-0.04 ppm) contained
Dieldrin residues in their body fat greatly exceeding the FDA
"safe limit" of 0.3 ppm and ranging up to 30 ppm (Moore, 1975).
The chickens had to be destroyed as unfit tor human consumption
(Pesticide Chem. News, 1974).
II. METABOLISM
The breakdown pathways of the cyclodienes are relatively
complex (Brooks, 1973) and are still in the process of
elucidation. Many of the degradation products are highly active
neurotoxins—e.g., photodieldrin—and present a substantial
degree of environmental hazard. The metabolic pathways can only
be summarized here,
Aldrin and dieldrin. The dominant reaction of Aldrin is
epoxidation at the double bond to form the 6,7-ej>oxide dieldrin.
This is a microsomal oxidation and occurs photochemically and
biologically in soils, plant tissues, and in all animals studied
(Gannon and Decker 1958). Thus the very stable Dieldrin appears
everywhere in the environment as the major contaminant following
the use of Aldrin. Further biological or photochemical reaction
of Dieldrin produces photodieldrin or 10-oxa-3,6-exo-4,5,13,13-
hexachloro-(6.3.1.13,*.1»,»».02,7.0*,i2)tridecane a cage-like
compound (Matsumura et al., 1970). Photodieldrin is about 5
times more acutely toxic to laboratory animals then Dieldrin.
Aldrin is also degraded in plants and animals to hexachloro-
hexa hydro-1,
-------
89
degraded, largely to 9-ketoendrin and 9-hydroxyendrin, but also
to 5-hydroxyendrin (Baldwin et al., 1970).
Heptachlor and Heptachlor epoxide. Heptachlor is rapidly
oxidized to the 2,3-heptachlor epoxide (Davirtow and Radomski,
1953). This is a microsomal oxidation and occurs both
photochemically and biologically in soils, plant tissues, and all
animals studied (Gannon and Decker, 1958) . Thus, the stable
heptachlor epoxide appears everywhere in the environment as the
major contaminant after the use of Heptachlor. Heptachior
epoxide is more toxic to animals than heptachlor. Heptachlor
differs from Aldrin, in that it is much more easily hydrolyzed,
because of the al.lyclic C=C-CHC1 structure, to form 1-
hydroxychlordene or 1-hydroxy-4,5,6,7,8,8-hexachloro-3a,4,7,7a-
tetrahydro-4,7-methanoindene, which is converted to the 2,3-
epoxide, an excretory metabolite in animals (Lu e_t al. , 1975).
Heptachlor forms a pnotoproduct, photoheptachlor. Heptachlor
epoxide forms photoheptachlor epoxide and slowly hydrolyzes to
the diol (Menzie, 1974).
Chlordane. Both the cis- and trans- Chlordanes form a single
epoxide, Oxychlordane, or 1-exo-2-endo-4,5,6,7,8,8-octachloro-
2, 3-exoepoxy-2,3,3a,4,7,7a-hexahydro-4,7-methanoindene (Schwemmer
et al., 1970). This has only recently been recognized as the
major terminal residue in animal tissues and milk after ingestion
of Chlordane (Barnett and Borough, 1974). Oxychlordane is more
toxic to animals than either of the Chlordane isomers. There is
also evidence of the formation of hydrophilic degradation
products, such as chlordanedihydrodiol and 1-hydroxy-2-
chlorodihydrochlordene (Korte, 1967). Other degradation products
identified include 1-hydroxychlordane and photochlordane, a cage-
like compound (Menzie, 1974).
III. HEALTH ASPECTS
The effects of the cyclodienes on animal and human health are
very subtle and complex. These are the most hazardous of all
pesticides, because of their persistence, fat storage, and
central nervous system target site. Their effects can be
reviewed only briefly here.
A. Observations in Man
Human illness and death have been observed after poisoning
during the manufacture, spraying, or accidental ingestion of the
cyclodienes. Typical symptoms of poisoning result from
stimulation cf the central nervous system and include headache,
blurred vision, dizziness, slight involuntary muscular movements,
sweating, insomnia, bad dreams, nausea, and general malaise.
More severe illness is characterized by jerking of muscles or
-------
90
groups of Muscles and epileptiform convulsions, with loss of
consciousness, involuntary incontinence of urine and feces,
disorientation, personality changes, psychic disturbances, and
loss of Memory. Such seizures May recur for 2-4 Months after
cessation of exposure and are Marked by abnormal encephalographic
patterns. These syMptoms of severe poisoning have developed in
10 - 20% of spraymen working in WHO house-spraying programs
(Hayes, 1957, 1959), and such poisoning has not been eliminated
in any spray program.
Epidemics of Endrin poisoning have occurred after the eating
of bread Made from flour accidentally contaminated with Endrin;
there were 59 illnesses in one episode (Cavies and Lewis, 1956)
and 87%, with 26 deaths* in Saudi Arabia (Weeks, 1967). At least
97 cases of fatal Endrin poisoning were recorded through 1965
(USEPA, 1973a) . It appears that ingestion of Endrin at 0.2 -
0.25 Mg/kg can produce convulsions in humans (Hayes, 1963).
Workers in a plant manufacturing and formulating Aldrin,
Dieldrin, Isodrin, and Endrin had epileptiform convulsions (3.3%)
and had encephalograms suggesting brain stem injury (20.5%) . The
encephalograms usually returned to normal within 3-6 months
after exposure ceased (Hoogendem et al. , 1962) .
B. Observations in Other Species
Acute Effects. The acute dermal and oral LD,o values of the
various cyclodienes and key degradation products in rats, as
measured under uniform conditions, were given by Hayes (1963) and
are summarized in Table VI-18.
-------
TABLE VI-18: IDsj^s of Cyclodienes
Substance Oral LD^n,ntq/kq Dermal LDSO, mq/kq
Male
Aldrin 39
Dieldrin 46
Photodieldrin 9.6
Endrin 17.8
Chlordane 335
Heptachlor 100
Heptachlor epoxide 46.5
Endosulfan 13
Female
60
46
7.5
430
162
61.3
18
Male
98
90
-
840
195
130
Female
98
64
15
690
250
74
-------
93
Not only are such compounds as Endrin extraordinarily toxic (it
is registered u.s a rodenticide) , but the dermal toxicity is
roughly equivalent to the oral toxicity.
Chronic Effects. The results of chronic feeding of the
cyclodienes to laboratory animals are extraordinarily severe, and
true no-adverse-effect dosages have never been determined for
some of the compounds, such as Dieldrin, Keptachlor, and
Chlordane (Walker et al., 1972). Toxicological evaluation is
complicated by the in vivo conversion of the cyclodienes to
epoxides by microsomal oxidation: Aldrin to Dieldrin, Heptachlor
to Heptachlor epoxide (Davidow and Radowski, 1953) and Chlordane
isomers to Oxychlordane (Schwemmer et al., 1970). Dieldrin,
Heptachlor epoxide, and Oxychlordane are very persistent and fat
soluble and are the dominant metabolites stored in human and
animal tissues and excreted in milk. The amounts of these
cyclodienes found in human adipose tissue? in 1970-1974 were:
Dieldrin 0.00-15.2 ppm (mean, 0.18 ppm); Heptachlor epoxide,
0.00-10.62 ppm (mean, 0.17 ppm); and Cxychlordane (mean, 0.15
ppm) (NAS, 1975) .
Chlordane fed to rats at 2.5 ppm caused slight liver damage
(Lehman, 1952). Heptachlor fed to rats at 0.3-1.0 ppm resulted
in the accumulation of Heptachlor epoxide in the body tat. When
it was fed to dogs at 1 mg/kg/day, three of four animals died in
265-424 days; at 5 mg/kg/day, death occurred in 21 - 22 ^ays
(Lehman, 1952). Aidrin fed to rats at 5 ppm produced no adverse
jffects; fed to dogs at 1 mg/kg/day, it caused death in ?'\ - 22
days (Lehman, 1952).
Dieldrin fed to rats at 5 ppm produced no adverse effect.
When it was fed to dogs at 0.5 mg/kg/day, two of four animals
died, in 14 and 201 days; 1 mg/kg/day, both animals tested died,
in 83 and 300 days; at 2 mg/kg/day, both animals died, in 22 and
35 days (Lehman, 1952). In recent studies, Dieldrin fed to mice
at 2.5 and 5 ppm,in the diet shortened the life span; at 0.1-1.0
ppm, it caused a progressive increase in malignant hepatomas
(Walker et al., 1972). Thus, the no-adverse-effect dosage has
never been determined.
Endrin fed to rats at 1 and 5 ppm in the diet produced no
obvious effects over the life span, except for liver enlargement
at 5 ppm. When it was fed at 25 ppm, the life span was
shortened, and diffuse degeneration was seen in train, liver,
kidneys, and adrenals. Mice fed Endrin at 0.1 - 4.0 ppm over
their life span showed increased liver weights at 2 and 4 ppm anrl
vascular damage of liver cells. Convulsions were observed in
dogs fed 2 and 4 ppm, and autopsies revealed pathologic chancres
in the brain (USEPA, 1973a).
-------
33
Aldrin, Dieldrin, and Endrin at very low dosages affect the
central nervous system, producing encephalographic changes and
altering behavior. Medved et al. (1964) found that cats fed
Aldrin at 1 mg/kg/day or made to inhale 0.1 pg/liter of air had
marked lowering of conditioned reflexes and of unconditioned fcod
and orientation reflexes, which required up to 8 days to return
to normal. Sheep fed Dieldrin at 0.5 and 2.5 mg/kg/day had
abnormal encephalographic and behavioral responses (Sardler et
al., 1968, Van Gelder et al-, 1969).
Mutagenicity. Dieldrin was not mutagenic in the
Salmonella/microsome test (McCann, 1975). There is no available
information on Aldrin, Endrin, Chlordane, !?eptachlor and
Heptachlor epoxide.
Ca rci nogenicity. The Mrak Commission (Mrak, 1969) judged
Aldrin, Dieldrin, and Heptachlor as positive for tumor induction
in one or more species of laboratory test animals-. Dieldrin fed
to mice (CFA) for 2 years (Walker et al., 1972) produced a
dosage-dependent incidence of hepatomas. In males, the
incidences were: controls, 7*, on 0.1-ppm Dieldtin, 21?; on 1-ppm
Dieldrin, 28%; and on 10-ppm Dieldrin, 53%. In females, the
incidences were: controls, 4%; on 0.1-ppm Dieldrin, 307,; on 1-ppm
Dieldrin, 42/6; and on 10-ppm Dieldrin 62*. Although the
malignant nature of these tumors was questioned by the
experimenters, they were later declared as true metastatic
malignancies by a panel of experts (USEPA, 1974:1) . Experiments
with rats ana dogs were less definitive (Walker et al. , 1969).
An additional 2-year feeding study with Lieldrin and
Photodieldrin has been reported by Walton et al. (1971).
Heptachlor epoxide fed to rats (CFA1) over a 2-year period at
0.5, 2.5, 5.0, 7.5, and 10 ppm in the diet produced increased
numbers of tumors, mostly adrenal, in all groups, compared with
controls. Even at 0.5 ppm, there was a 62.5% incidence of tumors
in male rats, compared with 34.78% in controls, and 82.61%
incidence in female rats, compared with 54.17% in controls. From
these apparently unpublished results, Heptachlor epoxide was
judged as a highly potent carcinogen (Kettering Laboratory,
1959) .
Chlordane and Heptachlor were evaluated for carcinogenicity
by the National Cancer Institute and were found to be
carcinogenic in mice (B6C3S1) , with a high incidence of
hepatocellular carcinomas when fed over an 80-week period, and in
rats, in which hepatic nodules and liver hyperplasia were
produced. Chlordane fed at 5f. ppm produced 88.9% hepatocellular
carcinoma in male mice, compared with 10% in controls, and fed at
64 ppm produced 69.6% hepatocellular carcinoma in female mice,
compared with 0% in controls. Keptachlor fed at 13.8 ppm
-------
produced 70.2% hepatocellular carcinoma in male mice, compared
with 11.1% in controls, and fed at 18.0 ppm produced 69.OX
hepatocellular carcinoma in female mice, compared with 10% in
controls. It was judged that both Chlordane and Heptachlor are
potent liver carcinogens in both sexes of mice, although the
results have apparently not yet been published (NCI, 1975).
Endrin was fed to rats at 2, 6, or 12 ppm in the diet for 2
years without producing primary malignant hepatic tumors or
increasing tumor incidence in any organs (Dieckmann et al.,
1970) .
Davis and Fitzhugh (1962) fed Aldrin at 10 ppm in the diet to
C3HeB/Fe mice for two years. There was a statistically
significant increase in the number of benigh liver tumors in the
Aldrin-fed mice as compared to controls. This study is cited by
the Mrak Commission (Mrak, 1969) to be positive evidence for
tumor induction for this compound.
Aldrin fed to rats at 2.5, 12.5 and 25 ppm in the diet for 2
years produced non-dosage-dependent tumors which were not
significantly different from the tumor incidences in the
controls. (Cleveland, 1966.)
*
Reproduction. Endrin fed to mice at 5 ppm for 30 days
produced significantly smaller litters than in controls.
However, 7 ppm had no significant effect on mean litter size and
1-tter production frequency when fed to Saskatchewan deer mice
(Peromyscus maniculatus) over intermittent periods. Pats fed 2,0
ppm over three generations had no observable effect in fertility,
gestation, viability, and lactation (cited in USFPA, 1973a).
When quail were fed 1 ppm, no eggs were produced during the
reproductive period. Endrin fed at 10 ppm reduced egg production
in pheasants and reduced survival of the chicks (Cited in USEPA,
1973a).
Evidence presented at EPA hearings (1974d) indicated
substantial effects of Dieldrin on animal reproduction. For
example, raccoons fed Dieldrin at 2 and 6 ppm in the diet
produced 20.0 and 20.2%, respectively, as many young as did
untreated controls. Litter size was also reduced. In further
study, raccoons fed Dieldrin at 2 ppm had abnormal estrous cycle,
reduced ovulation rate, reduction of pregnancy to 25-30% of that
in controls, increased resorption of embryos, and reduction in
litter size. Dieldrin also influenced spermatogenesis, sperm
quality, and fertility adversely in male raccoons.
Teratoqenicity. Aldrin, Dieldrin and Endrine were studied by
Ottolenghi et al. (1974) in hamsters and mice. Single oral doses
-------
of approximately one-half the respective LD5O doses were given on
days 7, 3 or 9 of gestation in the hamster and on day 9 of
gestation in the mouse. A significant number of defects were
produced in both species.
Chlordane was found not to be teratogenic in rats at 150 to
300 ppm in diet (Ingle, 1952).
IV. Carcinogenic Risk Estimates.
Dieldrin, Chlordane and Heptachlor have produced dose-related
hepatomas when fed to mice (Walker et al., 1972 and NCI, 1975).
For each compound the available sets of dose-response data were
individually considered as described in the risk section in the
margin-of-safety chapter. Each set of dose-response data was
used to statistically estimate both the lifetime risk and an
upper 95% confidence bound on the lifetime risk at the low-dose
level. These estimates are of lifetime human risks and have been
corrected for species conversion on a dose-per-surface-area
basis. The risk estimates are expressed as a probability of
cancer after a lifetime consumption of 1 liter of water per day
containing Q ppb of the compound of interest. For example a risk
of 1X10~* Q implies a lifetime probability of 2X10-5 of cancer if
2 liters/day were consumed and the concentration of the
carcinogen was 10 ppb (i.e. Q=10). This means that at a
concentration of 10 ppb during a lifetime of exposure this
compound would be expected to produce one excess case of cancer
for every 50rOOO persons exposed. If the population of the U.S.
is taken to be 220 million people, this translates into 4UOO
excess lifetime deaths from cancer or 62.8 per year. Since
several data sets are typically available the range of the dose
risk estimates are reported.
For Dieldrin at a concentration cf 1 itq/liter (Q=1) the
estimated risk for man would fall between 0.8-1.9X10-* Q. The
upper 95% confidence estimate of risk at the same concentration
would be between 1.9-2.1X10-* Q.
For Chlordane at a concentration of 1 ^g/liter (Q=1) the
upper 95% confidence estimated of risk for man would be between
0.96-1.8X10-5 Q.
For Heptachlor at a concentration of 1 jjg/liter (0=1) the
upper 95% confidence estimate of risk for man would be from 3.5
to 4.8X10-5Q.
-------
6
V. CONCLUSIONS AND RECOMMENDATIONS
The cyclodiene insecticides—particularly the persistent
epoxides, Dieldrin, Endrin, Heptachlor epoxide, and Oxychlordane-
-present the greatest hazards of all residual pesticides in
water. At lew dosages, they are highly active hepatocarcinogens
and have a dangerous effect on the central nervous system of man
and higher animals, leading to apparently irreversible changes in
encephalographic and behavioral patterns. They are highly
persistent biologically and can accumulate in animal fats and
exist in milk.
In light of the above and taking into account the
carcinogenic risk projections it is suggested that very strict
criteria be applied when limits for Dieldrin, Heptachlor and
Chlordane in drinking water are established. Before limits for
Aldrin, Endrin and Heptachlor epoxide in drinking water can be
established, more toxicological data must be gathered and
evaluated. The available chronic-toxicity data are summarized in
Tables VT-19, 20, 21, and 22.
-------
TABLE VI-19: Summary of Chronic Toglclty Data for Aldrin and Dieldrln
Highest
Mo-Adverse-
Dieldrln
rat (CFE)
dogs
(beagle)
Dosage Levels and Effect Level or
Duration Ho. of Animals Per Lowest-Minimal- Effect
of Study Croup Effect Level Measured Reference
132 weeks 0.0
0.1
1.0
10.0
2 years 0.0
0.1
1.0
10.0
2 years 0.00
ppm 288M 297F
ppm 124M 90F <
ppm HIM 89F
ppm 176M 148F
ppm 43M 23F
ppm 23M 23F
ppm 23M 23F
ppm 23M 23F
ppm 5M 5F
0.005 mg/kg/d 5M 5F
0.5
mg/kg/d 5M 5F
liver tumours Walker et j>l..
M6.9Z F 9.5Z 1972
C^O.l ppn M21Z F30Z
M36Z F42.5Z
M53.4Z F62.3Z
renal liver Walker «LL«1..
tumours 1969
M28Z F'«4Z
M26Z F65Z
<:0.l ppm M22Z F61Z
M35Z F52Z
ratios In-
creased
liver weight Walker et .1! .f
M3.37Z F3.32Z 1969
<0.1 ppa M3.61Z F3.56Z
M4.28Z F4.51Z
fthls compound Is an animal carcinogen^
Aldrin
Rat
Mice
2 years
0 38M 53F
2.5 29M 32F
12.5 30M 36F
25.0 26H 33F
2 years 107M 107F
10 ppm
ppa
10 ppm
Tumours
H7.89Z Fll.
M3.45Z F 3.
32Z
13Z
MO F 8.33Z
M3.85Z F 3.03Z
Hepatic cell
adenoma
Cleveland,
1966
Pavls and
Fltzhugh,
1962
JThis compound is an animal carcinogenTl
-------
TABLE VI-20: Su..ary of Chronic Tosicity Data for Endrln
OQ
»»• •*•
Duration Doaaie
Sp«cl«» of Study Level*
tat
2 yeara
Bos
(beagle)
Dot
Highest
•o-Adverae-
Effect Level or
Loweat-MlnlBal-
Bff«ct Level
2 pp.
6 pp.
12 pp.
19 .OBCh* 0
1 pp.
3 pp.
2 year* 0
(7 M, * 7 P
at aach 0.1 pp.
level)
0.5 pp.
1.0 pp.
2.0 pp.
4.0 pp.
0.3 pp.
Effect Measured
"no primary malignant cuaiora"
"no primary .allgnant tu«or«"
"no priiucy .allgnant cu.orc"
lncraa*ad liver/body ratio
Incraaaad liver/body ratio
convulcloa*, lncrea««d/llver
body ratio.cell depreciation
coaVylalona. lncrea»«d/llver
body ratlojc*ll depreciation
Reference
Delch.an
et al . ,
1970
Cited in
EPA, 1973
Cited in
EPA. 1973
fThla compound la a tuapected enl.al carcinofenTj
-------
TABLE Vl-21. Summary of Chronic Toxicity Data for Chlordane
Dosage Levels and Highest Ho-adverse-
Duration
Species of Study
Mice 90 wks
(B6C3F,)
1
Rat 110 wks
(CM)
No. of Animals per
Group
0 ppm M U8 F W
30 ppm
56 ppm
6U ppm
0 ppm M 7 F 10
121 ppm F 1*9
203 Ppn M U3
2U1 ppm F 1*3
U07 pm M U2
effect Level or Lowest Effect
Minimal-effect Level Measured Reference
liver tumors National
(carcinoma) Cancer Inst .^
< 30 ppm M 20* F 0* 1975
M 33* F 6.2*
F 88.9jb
-F 73.9*
liver tumors National
(carcinoma) Cancer Inst,
< 120 ppm M 0* F 0* 1975
F 2.0*
F 2.0*
F 2.3*
F U.7*
F 0.0*
•Liver hyperplasia: M;Olt controls, low dose 3.8*, high do*« I4* '
low dose I1* .7%, high dose UO.9%.
, FJ controls 0,
compound is an animal carcinogen/]
-------
TABLE TI-22.
ry of Chronic
Toxtcity Data for Beptacblor and Heptachlor Epoxide
iOO
Specie
Dosage Levels and
Duration Ho. of Animals per
of Study Group
Highest Mo-
adverse-effect
Level or Lowest-
Minimal effect Effect
Level neasured
Reference
Heptachlor
Mouse
(B6C351>
Rat
(OM)
90 wks 0 ppai M 58 F 40
6.1 ppm M 49
9.0 pp» F 46
13.8 ppa M 47
18.0 ppa F 42
110 wks 0 ppa M 10 F 10
18.9 ppm F 48
38.9 ppa M 43
37.8 ppm F 47
77.9 ppm M 45
{This compound is an animal carcinogen.^
Heptachlor Epoxide
Rat
(CFN)
2 yrs
/ • .j Pf*™1 ** *-^ *• ***
10.0 pp« M 23 F 23
<6.1 pp.
<18.9 ppm
<,0.5 ppm
fTb±s compound is a suspected animal carcinogen7]
liver tumors
(carcinoma)
N 11.1Z F 10Z
M 28 6Z
F 10.4Z
M 80.8Z
F 69.OZ
liver tumors
(carcinoma)
MO F 0
F 12.5Z
M 2.3Z
F 8.5Z
M 11.1Z
endocrine
tumors
M 35Z F 54Z
M 62.5Z F 82.6Z
M 60Z F 79.2Z
M 60Z
M 54Z
M 56Z
F 77Z
F 90.9 Z
F 73.9Z
National
Cancer Inst.j
1975
National
Cancer Inst.,
1975
Kettering
Laboratory,
1959
-------
tot
vi-a 9
TABLE VI-9 : Summary of Chronic Data for Propanil
Dosage levels and Highest no-adverse—
Duration No. of animal.?; per effect level or lowest—
Species of study _ group _ minimal -effect level
Bat
Dog
Effect
Measured
2 yrs 100, UOO, 1,600 ppm
(50 per group,
equal F, M)
UOOppm (20 mg/kg/day) ' No adverse
effect
Re f e rence
Ambrose et
al., 1972
2 yrs 100, 600, U,000 ppm 1»,000 ppm (100 mg/kg/day) Ho adverse Ambrosee_t
(U per group,
equal F, M)
effect
al. , 1972
Hat 3-generation 100, 300, 1,000 ppm 1,000 ppm (50 mg/kg/day) No reproduc- Ambrose c^
(20 F per group at tive effects JLL- » 1972
start)
Using an uncertainty factor of 1,000, suggested no-adverse-effect level in drinking
water is calculated as follows:
20 « 0.02 mg/kg/day (ADI), 0.02 x 70* x 0.1 a O.lU rag/liter.
100
Assume average weight of human adult - 70 kg.
Assume average daily intake of water for man *•- 2 liters, and th*t 2C$ of total intake
is from water.
Test study from which to calculate suggested no-adverse-effect level.
"Assume weight of rat « O.U kg and of dog « 10 kg; average daily food consumption of
rat « 0.02 kg and of dog 0.25 kg.
-------
102
4. TRIAZINES
ATRAZINE, SIMAZINE, PROPAZINE, CYANAZINE
I. INTRODT3CTION
These four herbicides are all derivatives of cyanuric
chlorides and are closely related in environmental properties.
Atrazine is 2-chloro-4-ethylamino-6-isopropylamino-S-triazine;
Simazine is 2-chloro-4,6-diethylamino-S-triazine; Propazine is 2-
chloro-4,6-diisopropylamino-S-triazine; and Cyanazine is 2-
chloro-**- (l-cyano-l-methylethylainino)-6-ethylamino-s-t riazine.
These herbicides are used largely in preemergence applications
for corn, sorghum, and sugar cane, with minor use on pineapple,
macadamia orchards, and turf grasses especially (Atrazine).
Simazine is also used in citrus, deciduous fruits, oineapple,
turf grasses, ornamentals, and nursery plantings (WSSA, 1974).
United States production is estimated as: Atrazine, 90
million pounds; Simazine, 5 million pounds; Propazine, U million
pounds; and Cyanazine, 1 million pounds (NAS, 1975). Atrazine is
the pesticide most heavily used in the united statps.
The solubilities of the triazine herbicides in water at 25°C
are: Atrazine, 70 ppm; Simazine, 5.0 ppm, Propazinr, 8.6 ppm; and
Cyanazine, 171 ppm (WSSA, 197U).
Atrazine was found in the New Orleans water supply at a.7,
5.0, and 5.1 ppb, and diethylatrazine at 0.27-0.51 ppb (USEPA,
197
-------
IUO
II. METABOLISM
In animals, the dominant metabolic reaction is N-
dealkylation, and rats have produced 20 metabolites from
Atrazine, including U-amino-N-ethyl-, U-amino-N-isopropyl-, U,6-
diamino-, Q-amino-N-acetyl-, and U-amino-N-isopropionyl-2-chloro-
S-triazines. Rabbits also excreted N-(chloro-1-amino-S-
triazinyl-6)-glucoside (Menzie 1969). No firm evidence of ring
cleavage has been found in degradation studies with bacteria,
plants, or animals.
Cyanazine degradation proceeds initially by hydrolysis of the
nitrile group and slower hydrolysis of the 2-chloro group. 2-
Hydroxycyanazine is the major metabolite found in rat feces. The
rat also produces the 4-amino derivative and the N-
acetylcysteinyl derivative and hydrolyzes; the cyano group to the
corresponding amide and carboxy derivatives (Menzies, 1974).
In a laboratory model ecosystem study, with carbon-11 ring-
labeled Atrazine, the environmental degradation products were 2-
amino-4-chloro-6-isopropylamino-S-triazine and 2-amino-U-chloro-
6-ethylamino-S-triazine. There was only a slight degree of food-
chain transfer of Atrazine (ecologic magnification 11 x in fish)
or any of its degradation products (Metcalf and Sanborn, 1975) .
Simazine residues from water treated at 2.5 ppm rose to a
maximum of 2.2 ppm in bluegill after 28 days and declined to 0.76
ppm after 60 days; in bass, they rose to 1.50 ppm after 28 days
and declined to 0.88 ppm after 60 days (USEPA, 1976c).
III. HEALTH ASPECTS
A. Observations in Man
No case of poisoning in man from Simazine, Atrazine,
Propazine, or Cyanazine has been reported, although exposure to
Simazine has caused acute and subacute dermatitis in the
U.S.S.R., characterized by erythema, slight edema, moderate
pruritus, and burning lasting « - 5 days (Elizarov, 1972).
B. Observations in Other Species
Acute Toxicity. The acute oral toxicity of Simazine in rats,
mice7~rlbbits, chickens, and pigeons was 5,000->5,000 mg/kg. The
acute dermal toxicity in rabbits was over 8.16 g/kg. For
Atrazine, the oral LDSO is 3,080 mg/kg in rats and 1,750 mg/kg in
mice For Propazine, the oral LDSO is over 5,000 mg/kg in rats
and mice. For Cyanazine the oral LDSO is 334 mg/kg in rats, and
the dermal LD50 is over 2,000 mg/kg in rabbits (WSSA, 197U) .
-------
Chronic Toxicity. Simazine fed to rats for 2 years at 1.0,
10, and 100 ppm produced no difference between treated and
control animals in gross appearance or behavior. The rats fed
100 ppm had approximately twice as many thyroid and mammary
tumors as the control animals, but it was stated that these were
not attributable to Simazine (USEPA, 1976c) .
Propazine at 250 mg/kg for 130 days produced no gross signs
of toxicity or pathologic changes (WSSA, 1974) .
Atrazine, in 2-year chronic-feeding studies at 100 ppm in the
diet of rats, produced no gross or microscopic signs of toxicity
(WSSA, 1974).
Cyanazine in 2-year feeding studies in rats and dogs, showed
no signs of toxic effects at levels up to 25 ppm (WSSA, 1974).
A 2-year chronic-feeding study of Simazine in dogs with
Simazine SOW fed at 15, 150, and 1,500 ppm showed only a slight
thyroid hyperplasia at 1,500 ppm and slight increases in serum
alkaline phosphatase and serum glutamic oxalacetic transaminase
in several of the dogs fed 1,500 ppm (USEPA, 1976c).
Mutaqenicity. Simazine and Atrazine were inactive in a
standard mutagenicity screen with microorganisms, e.g., Pimazine
was negative with four strains of Salmonella typhimurium (TJSEPA,
x976c). Plewa and Gentile (1975) demonstrated that extracts of
maize seedlings grown on soil treated with Atrazine at
recommended rates contain an agent that is highly mutaqenic in
Saccharomyces cerevisiae (PI). Further study (Gentile and Plewa,
1976) has shown that the kernels of maize grown on Atrazine-
treated plots contain this mutagenic agent, which produces
mutation rates up to 30 times that of untreated maize. These
data strongly suggest that maize plants can metabolize Atrazine
into a mutagenic agent and generate considerable concern about
ubiquitous triazine residues in water supplies.
Carcinogenicity. Atrazine, Propazine and Simazine were fed
to 2 strains of mice at 21.5, 46. U and 215 mg/kg/day respectively
for 80 weeks (Innes et al., 1969). The incidences of hepatomas
were: 4.24% in controls, 5.6% in Atrazine treated, 5.7* in
Propazine treated, and 5.6% in Simazine treated.
Reproduction. Simazine at 50 and 100 ppm in the diet had no
adverse effects on reproduction of rats or offspring over three
generations (USEPA, 1976c). Similar experiments with chickens
and quail showed anomalies in the urogenital tracts of male
chickens when eggs were sprayed with 0.5, 0.7, 1.0, and 1.5*
aqueous solutions of Simazine (Didier and Lutz-Ostertag, 1972).
-------
Teratogenicity. No available data.
V. CONCLUSIONS AND REGCMMENDflTIONS
Atrazine, Propazine and Simazine all appear to have low
chronic toxicity. The only good carcinogenicity feeding study
done on these compounds did not reveal a significant increase in
cancer incidence over controls. On the basis of these chronic
studies an ADI was calculated for each of these compounds. The
ADI for Atrazine is 0.0215 mg/kg/day, for Propazine O.OU64
mg/kg/dayr and for Simazine 0.215 mg/kg/day. The available
chronic toxicity data for Atrazine, Simazine and Propazine are
summarized in Table VI-10.
-------
108
TABLE VI-10. Suamary of Chronic Data for Atrazine, Simazlne and Propazine
Species
S imagine
Bat
Bat
Dog
Mouse
Atrazine
House
Duration Dosage
of study levels
2 yrs.
8 utbs.
2 yrs.
80 wks.
80 wks .
0
1.0 ppm
10 ppm
100 ppm
10 mg/kg/day
50 mg/kg/day
100 mg/ke/day
0
12 ppm
120 ppm
1,200 ppm
Higbest no-adverse
effect level or lowest
minimal effect level Effect Measured
toaors 13.
timors
<12 ppm
ft
215 mg/kg/day { 215 mg/kg/day
av. length life 200 days
av. length life 151 days
av. length life 126 days
thyroid/body ratio 0.006
thyroid/body ratio 0.009
thyroid/body ratio O.O09
thyroid/bo-"-/ ratio 0.011
Hepatoma k.2$>
Hepatoma 5•&&
21.5 mg/kg/day 21*5
Hepatoma U.2%
Hepatoma 5.6%
VT-5Q
Reference
Cited in
EPA
1976c.
Cited in
EPA
19?6c
Cited in
EPA
19?6c
Innes
et al.j
Innes
et al
Propazine
Mouse 80 vks.
c Hepatoma
^ A «&^>f*W» ^V^ll»"~ < W
U6.U mg/kg/day U6.U ng/kg/day Hepatoma 5.
Innes
et al.j
Using an uncertainty factor of 1,000, suggested no-adverse-effect level for Simazine in
drinking water is calculated as follows:
215 » 0.215 mg/kg/day (ADI), 0.215 x 70d x O.le » 1.505 nvg/liter
looo
Using an uncertainty factor of 1,000, suggested no-adverse-effect level for Atrazine in
drinking water is calculated as follows:
21.5 = 0.0215 ing/kg/day (ADI), 0.0215 x ?0d x 0.1C » 0.15 mg/liter
1000
Using an uncertainty factor of 1,000, suggested no-adverse-effect level for propazine in
drinking water is calculated as follows: ^ e
k6.k * O.OU6U Bg/kg/day (ADI), 0.0^6^ x 70 x 0.1 = 0.32 ing/liter
a b c 100°
' ' Test studies from which to calculate suggested no-adverse-effect level.
Assume average weight of human = 70 kg.
CA»sume agerage daily intake of water for man = 2 liters, and that 2OJ of total intake
is from vater.
-------
10?
DDT and DDE
I. INTRODUCTION
DDT, or 2,2-bis-(E-chlorophenyl)-lrl,l-trichloroethane, was
patented as an insecticide in 1939 by Swiss chemist Paul Muller.
After a period of extensive use for the control of malaria,
typhus, and other insect-transmitted diseases during World War
II, it became the prototype of the synthetic insecticides. At
the height of its use in the United States, in 1963, production
was 176 million pounds, and DDT was registered tor use on 334
agricultural commodities. DDT has been used very extensively all
over the world, both in malaria control and in agriculture, and
it is estimated that more than 4.4 billion pounds has been used
for insect control since 1940, about 80% in agriculture. Because
of the extensive environmental problems resulting from its
stability and high lipid-water partitioning, DDT was banned for
all but essential public-health use in the United States on
January 1, 1973.
DDT is produced by condensing chlorobenzene with chloral. The
technical product contains about 80-90% p_,p_'-isoiner. DDT is
soluble in water at 0.0012 ppm at 25°C.
The persistence of DDT, DDE[ or 2,2-bis-(p-chloropheny1) -1,1-
dichloroethylene ], and DDD *or 2,2-(rr-chlorophenyl)-1,1-
dichloroethane] has made them ubiquitous contaminants of water.
The total residues are commonly referred to as "DDT-T". In an
extensive 1958-1965 survey of the rivers of the United States,
Breidenbach et al. (1967) found DDT in every river surveyed at
0.008-0.144 ppb; DDE at 0.002-0.011 ppb, and DDD at 0.004-0.080
ppb. The highest concentrations were generally found in the West
and South, where 44% of the samples were positive for DDT and 38%
for DDE. More than 500 grab samples of finished drinking water
and related raw water from the Mississippi and Missouri Rivers
were analyzed by Schafer et al, (1969); more than 33% of the
finished-water samples contained DDT-T.
An EPA study of over 700 water utilities serving airplane,
train, and bus terminals showed DDT in six of 106 samples at 1-2
ppt and in five of 83 samples of finished water at 6-68 ppt
(USEPA, 1975J) .
In Iowa, Richard et al. (1975), assayed DDE in various
surface, subsurface, and finished waters. Water from the South
Skunk River near Ames contained DDE at 3 - 1,820 ppt, with the
highest concentrations in June 1974. Similar results were found
in Indian Creek (2 - 3,920 ppt), and in a drainage ditch near
Fernald, Iowa (4 - 1,150 ppt). Surface water had DDE at 1 - 248
-------
108
ppt (average, 68 ppt) in the Des Moines River, 2-250 ppt
(average 59 ppt) in the Raccoon River, 8 - 350 ppt (average, 212
ppt) in the Red Rock Reservoir, and 5 - 1,121 ppt (average, H20
ppt) in the Rothbun Reservoir. Other surface-water values found
were: Cedar River, 480 ppt; Iowa River, 350 ppt; Des Moines
River, 74 ppt; and Mississippi River (near McGregor Iowa) , 2 ppt.
The Mississippi at New Orleans had DEE at 18 ppt. Finished water
at Cedar Rapids contained DDE at 28 ppt, but other finished water
had less than 0.5 ppt.
Lake Michigan contains DDT-T at an average of 6 ppt.
Most fishes from Lake Michigan contain DDT residues in excess of
the 7 ppra FDA "safe limit" and the overall tiomaonification from
water to fish may exceed a factor of 3 x 10*.
Water standards have been proposed for DDT in finished water
(Schafer et al., 1969). The DDT-T concentration suggested in
1965-1966 and based on maximal acceptable concentrations of the
Subcommittee on Toxicology was 42 ppb. This was drastically
lowered to 0.5 ppb, by Ettinger and Mount (1969) , on the basis of
a maximal reasonable stream allowance.
DDT and its breakdown products are ubiquitous and, because of
biomagnification and persistence, are in virtually every food
product. "Market-basket" surveys of the U.S. diet, collected in
five major O. S. cities and designed to represent the diet of a
,6 to 19-year-old male, show the intakes in Table VI-23 (MAS,
1975).
-------
109
TABLE VI-23. Pesticides in Diet
Daily Dietary Intake, in mg
Pesticide
DDT
DDE
DDD
1965
0.031
0.018
0.013
1966
0.041
0.028
0.018
1967
0.026
0.017
0.013
1968
0.019
0.015
0.011
1969
0.016
0.011
0.005
1970
0.015
0.010
O.OOU
6-Year
Average
0.025
0.017
0.011
DDT-T 0.062 0.087 0.056 0.045 0.032 0.029 0.053
-------
110
Calculated as human intake in mg/kg/day, the combined DDT-T
was about 0.2 that of the FAO/WHO Acceptable Daily Intake of
0.005 mg/kg/day. The dietary intake was 0.0089 mg/kg/day in
1965, 0.0010 in 1966, 0.0008 in 1967, and 0.0007 in 1968 (Mrak,
1969).
DDT in milk. DDT is present in milk, everywhere. Moore
(1975) surveyed Illinois milk in 1971-1973 and found DDT at 0.05
ppm in 1971, 0.02 ppm in 1972, and 0.03 ppm in 1973. The human
is at the top of the food pyramid, so human milk is especially
contaminated. Curley and Kimbrough (1969) found DDT-T residues
averaging 0.0784 ppm in U.S. samples (range, 0.OUOU-0.1563 ppm).
II. METABOLISM AND DEGRADATION
Although DDT is highly stable and persistent, it does undergo
a relatively complex series of degradative changes, both
biologically and environmentally. The dominant reaction is
dehydrochlorination to form DDE, which is much less toxic to
insects and higher animals, but has about the same solubility in
water (0.0013 ppm) and high lipid-water partitioning. DDE is
almost nondegradable, both biologically and environmentally.
Thus, DDE is the predominant residue stored in tissues,
increasing in relative concentration for each trophic level
(Woodwe11 et al., 1967) and reaching about 70% of DDT-T in humans
(Durham 1969). Nothing is certain about the degradation pathway
of DDE.
DDT is also reductively dechlorinated in biologic systems to
form ODD. DDD is less stable than DDT or DDE and is the first
step on the degradation pathway in animals (Morgan and Roan,
1S7U) and in the environment (Metcalf, 1973). DDD is
dehydrochlorinated to DDMU, or 2,2-bis-(p-chlorophenyl) -1-
chloroethylene; reduced to DDMS, or 2.2-bis-(p-chlorophenyl) -1-
chloroethane; dehydrochlorinated to DDNU, or 2,2-bis-(p-
chlorophenyl)-ethylene; reduced to 1,1-bis-(p-chlorophenyl) -
ethane; and eventually oxidized to DDA or bis-(p-chlorophenyl) -
acetic acid. This compound is much more soluble in water than
DDT and is the ultimate excretory product of DDT insertion and
storage in higher animals and humans. Environmentally, DDT
residues are converted to p,p'- dichlorohenzophenone.
DDT is also degraded to a slight extent by microsomal oxidase
enzymes by attack at the a-R to form dicofol, or 1,1-bis-(p-
chlorophenyl)-2,2,2-trichloroethanol. Very recently, a new
anaerobic degradation pathway, found especially in sewage sludcre,
was discovered in the conversion by bacteria to form DDCM, or
-(p-chlorophenyl)-acetonitrile (Metcalf, 1973).
-------
111
The kinetics of storage and loss of DDT and DDE in humans has
been investigated intensively (Durham, 1969; Morgan and Roan,
1974). In humans, DDT is stored in fat at about 10 times the
concentration of intake. The average U.S. inhabitant in 1961 had
DDT-T stored in his fat at 10 ppm; about 70% of this was DDE.
Storage can reach very high values; e.g., a DDT formulator stored
DDT-T at 1,131 ppm, 43X of it as DDE (Durham, 1969). Conversion
of DDT to DDE in the human body is very slow, i.e., loss than 20^
over 3 years. DDT is eliminated from the human body t-hrouqh
first-order reduction to ODD and conversion to the morf water-
soluble DDA, with a biologic half-life of about 1 year. DDE is
eliminated much more slowly, with a biologic hali-life of about 8
years. Its pathway of elimination is unknown; it may be slowly
excreted as DDE (Morgan and Poan, 1974).
III. HEALTH ASPECTS
A. Observations in Man
There are no definite exairples of human fatality due to
ingestion of DDT, but a dosage of 10 mg/kg has produced illness
in some (but not all) subjects, without convulsions. convulsions
have freguently occurred at 16 mg/kg or higher. Human volunteers
have consumed 35 mg/day (about 0.5 mg/kg/day) for as long as 25
months without ill effects (Hayes, 1963). These subjects stored
101 - 466 ppm in their body fat after 12 months and 105 - 659 ppm
after 21 months.
DDT-T concentrations found in human fat over FY 1970-1974, in
over 1,400 bioassays of U.S. human tissues, were 11.65, 11.5,
9.91, 8.91, and 7.83 ppm in fiscal 1970, 1971, 1972, 1973, and
1974, respectively (NAS, 1975).
The decline undoubtedly represents the effects of decreased use
and the banning of DDT in 1973.
B. Observations in Other Species
A^-ute Effects. The oral LD50 of DDT in rats is 113 mg/kg in
males and 118 mg/kg in females. The dermal LD50 in female rats
is 2,510 mg/kg (Hayes, 1963). DDE has an oral IDSO in rats of
880 mg/kg in males and 1,240 nig/kg in females. DDA has an oral
LD5o in rats of 740 mg/kg in males and 600 mg/kg in females.
The oral LD50 of DDT in dogs is 60-75 mg/kg, in rabbits is
250-400 mg/kg, and in mice is 200 mg/kg (Pimentel, 1971).
Chronic Effects. When rats were fed DDT at 5-10 ppm over the
lifetime, microscopic alterations were reported in liver cells,
including centrilobular enlargement with increased oxyphilia and
peripheral margination of the basophilic granules. These effects
-------
11
became moderate when DDT was fed at 50 ppm and were pronounced at
400 ppm; however, 50 ppm was tolerated without gross toxicity,
and 100 ppm with only slight symptoms of poisoning (Lehman,
1952a). The high lipid-water partition results in pronounced fat
storage; when DDT was fed at 1 ppm to rats for 15 weeks, it was
stored in fat at 13 ppm in males and 18 ppm in females, and the
corresponding values for 50 ppm were 28H and 588 ppm (Lang et
al. , 1950). It has been estimated that fat storage occurs at
about 20 times the dietary intake.
Mice fed DDT at 100 ppm in the diet had a considerably
shortened life span, although this was not apparent at 50 ppm
(walker et al., 1972).
Dogs tolerated daily DDT intakes of 10 mg/kg in corn oil for
three years without gross effects, but died after a few months at
50 and 80 mg/kg (Lehman, 1952b).
Mutagenicity. DDT was not mutagenic in the
Salmonella/microsome test (McCann et al., 1975) .
Carcinogenicity. The Mrak Commission (1969) judged DDT to be
positive for tumor induction in one or more species of test
animals. This, with its high persistence and rate of fat
storage, has caused substantial environmental concern. Tarjan
and Kerneny (1969) showed a generalized increase in freguency of
amors in five generations of mice after feeding DDT at 3 ppm,
and Faur and Kemen (1969) found increased numbers of malignancies
when DDT was fed to mice at 0.3 - 0.6 mg/kg of body weight. The
WHO has repeated these studies and found that DDT fed to mice at
0.3 mg/kg/day over a lifetime produced a significant increase in
liver tumors in males (WHO, 1973).
Teratogenicity. Although the thickness of egg shells of
birds was reduced by DDT (Mickey and Anderson, 1968), no
teratogenic effects have been identified in chicks, mice (Ware
and Good, 1967) or in rats (Ottoboni, 1969).
IV. CARCINOGENIC RISK ESTIMATES
Despite the positive results in mice, oral administration of
DDT to rats has not provided convincing evidence of
carcinogenicity. Feeding studies on dogs and monkeys have also
not shown DDT to be carcenogenic, but these studies are of
limited value due to small group size and short duration.
Studies on human workers occupationally exposed to DDT have
not shown an increased incidence of cancel", but these studies are
limited by time factors. Terminal cancer patients have been
-------
113
observed to have higher fat concentrations of DDT, but a causal
relationship is difficult to prove (IARC, 1974).
Only the data from feeding studies in mice can be
statistically treated to provide an estimate of risk for man.
Several species of mice have developed hepatomas after oral
exposure to DDT.
The available sets of dose response data were individually
considered as described in the risk section in the margin-of-
safety-chapter. Each set of dose-response data was used to
statistically estimate both the lifetime rl sk and an upper 95%
confidence bound on the lifetime risk at the low dose level.
These estimates are of lifetime human risks and have been
corrected for species conversion on a dose-per-suifac^-area
basis. The risk estimates are expressed as a probability of
cancer after a lifetime consumption of 1 liter of water/day
containing Q ppb of the compound of interest. For example, a
risk of 1X10-* Q implies a lifetime probability of 2X10~5 of
cancer if 2 liters per day were consumed and the concentration of
the carcinogen was 10 ppb (i.e. Q=10) . This means that at a
concentration of 10 ppb during a lifetime of exposure thin
compound would be expected to produce one excess case of cancer
for every 50,000 persons exposed. If the population of the U.S.
is taken to be 220 million people this translates into 4400
excess lifetime deaths from cancer or 62.8 per year. Since
several data sets are typically available the ranqe of the low
dose risk estimates are reported.
For DDT at a concentration of 1 pg/liter (0=1) there are
several risk estimates depending on which feeding study is
evaluated. Four studies (Innes et al., 1969; Tomatis et al. ,
1972- Walker et al., 1972; and Thorpe and Walker, 1973) provide a
risk'to man of from 0.18-13.OX10-* Q. The upper 95% confidence
estimate of risk at the same concentration is from 0.65-20.0X10-6
Q-
V. Conclusions and Recommendations
DDT is of moderate acute toxicity to man and most other
organisms. However, its extremely low solubility in water(0.0012
ppm) and high solubility in fat (100,000 ppm) result in great
bicconcentration. Its principal breakdown, product, DDE, has
very similar properties. Both compounds are also highly
persistent in living organisms, so the major concern about DDT
toxicity is related to its chronic effects, which are summarized
in Table VI-2U.
In light of the above and taking into account the
carcinogenic risk projections it is suggested that very strict
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114
criteria be applied when limits for DDT and DDE in drinking water
are established.
-------
TABLE VI-24. Summary of Chronic Toxicity Data for DDT and DDE
Species
Mouse
Rat
Dog
Man
Duration
of S tudy
5 genera-
tion
3 years
21.5
wraths
Highest Ho-
adverse-effect
Dosage Levels and Level or lowest
No . of Animals per Minimal-effect
G roup Level
0 (406 animals)
3 ppm (684 animals) 3 ppm
0.3-0.6 mg/kg/d
0.3 mg/kg/d
2 years 5 ppm
10 ppm
50 ppm
100 ppm
400 ppm
10 mg/kg/day (in
corn oil)
50 mg/kg/day (in
corn oil)
80 mg/kg/day (in
corn oil)
0.5 mg/kg/day
*0.3 mg/kg/day
^0.3 mg/kg/day
^ 5 ppm
10 kg/day
Effect
measured
2.232 tumors
1.232 leukemia
28.4%tumors
11.572 leukemia
tumors
liver tumors
altered liver
cells
altered liver
cells
moderate liver
Reference
Tarjan and
Kemeny, 1969
Faur and Kerne r.y
1969
WHO, 1973
Lehman, 195 2 a.
slight chronic
poisoning
pronounced liver
damage, Nervous
tremors
no adverse
effect
died
died
fat storage to
105-659 ppm
Lehman, 1952b
Hayes 1963
(ibis compound is an animal carcinogen.}
-------
TABLE VI-26. Summary of Chronic Toxlcttv Data fat BHC Isoaurf
DM age levels
Htgh««t no-adverse
effect level or
Chemical fora and Duration
animal spec Its of study
RAT
BHC (tech)
?-BHC, -BHC
•BHC
V -BHC
Ct -BHC
f -BHC
Y -BHC
g -BHC
HOUSE
BHC (tech)
Ct -BHC
| -BHC
Y -BHC
$ -BHC
S -BI1C
BHC (tech)
Ct -BHC
fi -BHC
£ -BHC
Y> -BHC
Cl -BHC
0 -BHC
r -BHC
r -BHC
approx. 2 yrs
approx. 2 yrs
approx. 2 yrs
2 years
78 weeks
78 weeks
78 weeks
78 weeks'
24 weeks
24 weeks
24 weeks
24 weeks
110 weeks
110 weeks
id weeks
26 weeks
26 weeks
26 weeks
20 weeks
24 weeks
24 weeks
24 weeks
80 weeks
t, No. of animals lowest minimal
per group effect level
10,50,100,800 ppm (10H, 10F)
10,50,100,800 ppm (10M, 10F)
5,10,50,100,400,800,1600 ppm
(10M, 10F)
25,50,100 ppm
500,1000,1500 ppn (18-24M)
500,1000 ppn
500 ppm
500,1000 ppm
6.6,66,660 ppm (20M, dd strain)
100,250,500 ppm (20M, dd strain)
100,250,500 ppm (20M, dd strain)
100,2DP,SOO ppm (20M, dd strain)
200 ppm (30M,JOF;CF1 strain)
'•00 ppra (29M,.'9F;C71 strain)
600 ppm {20N;ICR-JCL strain)
600 ppra (20M;ICR-JCL strain)
600 ppra (20M;1CR-.1C1. strain)
600 ppm (20M;TCR-JC1. strain)
300,600 ppm
5l,100,2'jO ppra (30M,d^ strain)
50,100,250 ppm OCM.rid strain)
50,100,250 ppm OOM.d.l strain)
12.5,25,50 ppra (? ;NMRI strain)
800 ppm
800 ppn
800 ppm
100 ppn
300 ppm
500 ppm
500 ppm
1000 ppm
660 ppm
250 ppn
300 ppo
500 ppm
200 ppm
400 ppm
600 prnn
600 ppm
600 ppm
600 ppra
300 ppm
100 ppm
250 ppn
250 ppm
50 ppra
Effect measured
Reduced Hfespan, no
Increased tumor Incidence
No Increase In tumor
incIdence
Liver hypertrophy (nodular
hyperplasla, carcinoma at
1000 and 1500 ppm)
Liver hypertrophy
Liver hypertrophy
Liver hypertrophy
Hepatona (20/20)
Hepatic nodules (9/20),
Tumors at 500(20/20)
No adverse effect
No adverse effect
Hepatic tumors, lung
metastasea
Hepatic tumors, lung
metastsses
Hepatic nodules, tumors
Hepatic tumors, lung
Hepatic tumors, lung
Hepatic t'imors, lung
No adverse effect
Liver hypertrophy (hyper-
plasla, tumors at 250)
Liver hypertrophy
Liver hypertrophy(sllght)
No adverse effect
Reference
Fltjhugh,
1950
Truhaut 1994
Ito
1975
Nagasaki ft al.j
1971 1972s
Nagasaki «E «!..
I972b
Thorpe &
Walker 1975
Goto, at •!..
1972
Ito,
Herbst, et al.
1975
These compounds are animal carcinogens.
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It?
KEPONE
I. INTRODUCTION
"Kepone" is the trade name of decachlorooctahydro-1,3,4-
metheno-2H-cyclobuta (cd)pentalen-2-one; its common name is
"chlordeone," as designated by the International Standards
Organization. Kepone was introduced in 1958. More recently it
has been produced solely by the Life Science Products Company for
Allied Chemical in Hopewell, Virginia, with the total output
purchased by Allied Chemical. The Hopewell plant was closed in
July 1975, when a number of its workers were found seriously ill.
In August 1975, the EPA ordered that sales and use of the
compound be stopped and prohibited further manufacture.
Kepone was registered for the control of root-borers on
bananas with a residue tolerance of 0.01 ppm. This constituted
the only food or feed use of Kepone. Nonfood uses included
wireworm control in tobacco fields and bait to control ants and
other insects in indoor and outdoor areas.
The U.S. production of Kepone for 1971 and 1875 was
approximately 850,000 Ib/year (Anonymous, 1976), and 99.2?? .of
this was exported to Latin America, Europe, and Africa. The
remaining 0.8% was used in the United States for ant and roach
traps or baits.
Kepone was made by the dimerization of
hexachlorocyclopentadiene in the presence of sulfur trioxide,
followed by hydrolysis of the sulfonated intermediate to kepone
(Brooks, 1974). The technical product (over 90% pure) sublimes
at 350°C (Spencer, 1973); it is relatively soluble in water (0.4%
at 100°C), compared with most chlorinated hydrocarbon pesticides.
Residual of Kepone has not been investigated in Market Basket
Studies by the FDA. Kepone was not found in adipose tissue of
humans in the monitoring programs of the Technical Services
Division, Office of Pesticide Programs, EPA.
II. METABOLISiM
Kepone is very stable in the environment. No degradation
products have been reported, although ultraviolet produced
dechlorinated products in a laboratory study (Alley et a_l.,
1974) No metabolic products have been reported; cows fed 5.0
ppm in the diet for 60 days excreted 90 ppb of Kepone in milk 3S
days after cessation of treated feeding (Smith an3 Ara^t, 1967).
-------
III. HEALTH ASPECTS
A. Observations in Man
Kepone came to public attention after Life Science Products
Company, which produced Kepone, was closed down when many
employees became seriously ill with such afflictions as tremors,
nausea, dizziness, impaired vision, and impotence. According to
an internal report submitted to the Director of the Center for
Disease Control by the Cancer and Birth Defects rivision. Bureau
of Epidemiology, Public Health Service, between March 1974 and
July 1975, 62 (55%) of 113 worker at the plant had clinical
findings that included nervousness, weight loss, pleuritic and
joint pains, oligospermia, tremor, opsoclonia, and ataxia.
Kepone was found in the blood of all 32 current employees, at
0.165 - 26 ppm. These were the first recorded cases of Kepone
poisoning in humans. Illness incidence rates were highest for
production workers and foremen and least for employees not
working directly in production. The mean latency Ketween start
of employment and onset of symptoms was 6 weeks. Symptoms have
persisted for as long as 6 months after employment was terminated
(Public Health Service, 1976).
Compa"nies using chlordecone have received Occupational Safety
and Health Administration (OSHA) notices that this substance is
hazardous and that its use should be strictly controlled. The
OSHA suggested that worker exposure to Kepone be kept below 100
jio/m' of air for up to 10 h/day or UO h/week, over a working
lifetime. There is no specific OSHA standard for this chemical.
According to a report in the March 1976 issue of the
Occupational Health Letter, Kepone is the cause of sterility in
exposed human males, in addition to harmful effects on the
nervous system and liver. Philip S. Guzelin, spokesman for a
team of researchers at the Medical College of Virginia, reported
on studies of 23 former industrial workers heavily exposed to
Kepone who exhibited overt signs and symptoms of toxicity. In
their investigations, the concentration of Kepone in whole blood
has been in parts per million, or thousands of times areater than
the minimal detectable concentration, and concentrations measured
in biopsies of liver, muscle, and adipose tissue have been
several times those in whole blood. Effective therapy for
Kepone-associated toxicity is unknown. In the absence of data on
the pnarmacokinetics of Kepone and the mechanisms of its
toxicity, rational treatment of exposed or afflicted people is
impossible.
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119
B. Observations in other Species
Acute Effects. The acute oral LD50» in corn oil solution, is
114 - 140 mg/kg in rats and 65 - 77 mg/kg in rabbits. The acute
oral LDSO of the formulated product is about 95 mg/kg in male
albino rats. The acute dermal LD50 is 3*15 - 375 mg/kg in rabbits
(Martinr 1972). The characteristic effect of this compound was
the development of DDT-like tremors. Acute rat inhalation
studies of 10% Kepone dust with exposures 2 and 10 times as
severe as those likely under agricultural conditions produced no
pathologic or other outward effects in rats (USEPA, 1976b) .
Chronic Effects and Carcinogenicity. Kepone has been
reported to be oncogenic in rats (USEPA, 1961) . Five groups of
male and female albino rats were fed Kepone at 2, 5, 10, 25, 50,
and 80 ppm for up to 2 years. Oncogenic effects appeared only in
rats receiving Kepone in their diets for 1-2 years. None of 23
control rats examined developed hepatocellular carcinomas. Among
the seven male rats fed at 25 ppm, liver lesions in one rat were
diagnosed as hepatocellular carcinoma by pathologists and
"evolving carcinoma11 by one pathologist, who also found "evolving
carcinoma" in a second male rat at this dosage. Among the 16
female rats that survived at 10 ppm, liver lesions in three were
diagnosed as hepatocellular carcinoma by one pathologist. Among
the nine female rats that survived at 25 ppm, liver lesions in
one were diagnosed as "evolving carcinoma" by one pathologist
(U.S. Dept. of Transportation 1976). Tremors developed, ranging
from slight at 25 ppm to severe at higher dosages.
The carcinogenesis bioassay data prepared by NCI (1976) show
the oncogenic effects of chlordecone on both sexes of osborne-
Mendel rats and B6C3F1 mice. Chlordecone was administered orally
at average dosages ranging from 8 to 26 ppm for rats and from 20
to 40 ppm for mice for 80 weeks. The mice were sacrificed after
90 weeks, and the rats after 112 weeks; moribund animals were
sacrificed and necropsied. Clinical signs of toxicity were
observed in both species, including generalized tremors and
dermatologic changes. None of the 225 control rats developed
hepatocellular carcinomas. Fourteen of the 68 male control mice
developed hepatocellular carcinomas. Pathologic diagnosis
revealed a statistically significant increase (p <0.05) in the
incidence of hepatocellular carcinomas in rats fed an average of
24 ppm (males) and 26 ppm (females) and in mice fed an average of
20 and 23 ppm (males) and 20 and 40 ppm (females) . Extensive
hyperplasia of the liver was also reported in both species (NCI,
1976).
Reproduction. It has been reported in the literature that
the administration of sublethal dosages of Kepone to male and
female mice caused interference with the reproductive process.
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120
Hubert (1965) reported that the major physiologic effects of
ingestion of sublethal dosages by laboratory mice, exclusive of
the liver and tremor syndrome, involved the reproductive
processes. The reproductive capacity of treated animals was
inhibited or severely reduced. The females were largely
responsible for the reduced reproduction. Data showed that the
female hormonal system was disturbed. In a separate and
independent mouse reproduction study (Good et al., 1965), authors
showed that the reproduction in mice was reduced at all dosages
used (10.0-37.5 ppw) ; both the size and the number of litters
were decreased. Increased dosage resulted in increased effects.
The reproductive effects of Kepone in rats have apparently not
been tested.
Mutaqenicity and Teratogenicity. There does not appear to be
data on the mutagenic and teratogenic properties of Kepone.
IV. CARCINOGENIC RISK ESTIMATES
Kepone has produced dose-related hepatomas when fed to mice
and rats (NCI, 1976). The available sets of dose response data
were individually considered as described in the risk section in
the margin of safety chapter. Each set of dose response data was
used to statistically estimate both the lifetime risk at the low
dose level. These estimates are of lifetime human risks and have
been corrected for species conversion on a dose-per^surface-area
basis. The risk estimates are expressed as a probability of
cancer after a lifetime consumption of 1 liter of water per day
cjntaining Q/ppb of the compound of interest. For example, a
risk of 1X10-* Q implies a lifetime probability of 2X10~5 of
cancer if 2 liters per day were consumed and the concentration of
the carcinogen was 10 ppb (i.e. Q=10). This means that at a
concentration of 10 ppb during a lifetime of exposure this
compound would be expected to produce one excess case of cancer
for every 50,000 persons exposed. If the population of the U.S.
is taken to be 220 million people, this translates into 4400
excess lifetime deaths from cancer or 62.8 per year. Since
several data sets are typically available the range of the low-
dose risk estimates are reported.
For Kepone at a concentration of 1 pg/liter (0-1) the
estimated risk for man would re between 2.2--6. OJMO-* Q- The
upper 95% confidence estimate of risk at th«r? sane concentration
would be from 1.4 to 8.0X10-* Q.
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121
V. CONCLUSIONS AND RECOmENDATIONS
Kepone is a very toxic compound and is persistent in the
environment. Test results clearly suggest that liver lesions,
including cancer, were induced in both sexes of rats and mice fed
chlordecone. In addition, the time to detection of the first
hepatocellular carcinoma observed at death was shorter for
treated than for control mice and, in both sexes and both
species, it appeared inversely related to the dose.
In light of the above and taking into account the
carcinogenic risk projections it is suggested that very strict
criteria be applied when limits for Kepone in drinking water are
established. The available chronic oral toxicity data are
summarized in Table VI-27.
Apparently, little is known about the pharmacokinetics of
Kepone and its mechanisms of toxicity. There is a pressing need
for systematic investigation of the absorption, distribution,
biotransformation, and excretion of Kepone in humans and
experimental animals, to gain an understandaing of its toxicity
and to provide a basis for rational therapy.
There is also very little information on the environmental
transport mechanisms of Kepone and its degradation products, its
persistence, and its degradation in soil. Kepone residues have
been found in food crops grown in rotation with Kepone-treated
tobacco.
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122
BENZENE HEXACHLORIDE (BHC) AND LINDANE
I. INTRODUCTION
"Benzene hexachloride" (BHC) is the common name used to
designate the mixed isowers of 1,2,3,4,5,6-hexachlorocyclohexane.
"Hexachlorohexane* is the proper term for this compound; however,
because it is more customary, the trivial name, "benzene
hexachloride" (or BHC), will be used in this document.
BHC (technical grade) is a mixture of the eight possible
isomers that constitute the different spatial arranqements of the
six chlorine atoms on the trans- (or chair) form of the ring.
Its composition approximates 65% « isomer, 111 0, 13 - 14% T» 8 -
9% 6, and 1* c The lowest-melting-point (112.8 C) isomer, which
is also the most reactive known, is that designated as the r
isomer. The commercial insecticide Lindane is defined as a
product containing at least 99% 7 isomer (the remainder being
other BHC isomers). Technical BHC is prepared by
photochlorination of benzene. Production of the 7 isomer for
Lindane is achieved by selective crystallization (Melnikov,
1971) .
The different isomers have different solubilities in water
and different vapor pressures: a, 10 mg/liter and 0.06 torr; ^, 5
mg/liter and 0.17 torr; and 7, 10 mg/liter and 0.14 torr
lelnikov, 1971; NAS, 1975). The relatively high water
solubility and vapor pressure of Lindane cause it to have
relatively low persistence in the environment. Lindane has been
detected in the finished water of Streator, Illinois at 1
l*g/liter (USEPA, 1975J) .
The EPA has set an interim standard for Lindane in finished
water for 0.004 mg/liter (OSEPA, 1975i).
The insecticidal properties of BHC were discovered and
developed for commercial use in pest control beginning in 1942.
when it was found that virtually all the insecticidal activity of
BHC resided in the 7-isomer, major development of the latter as
an insecticide itself was rapid. Lindane has been marketed under
a large number of trade names as an insecticide. It has had
major use in insect control in domestic and commercial settings,
in numerous agricultural and silvicultural applications, and in
dips, sprays, and dusts for livestock and pets. Recent U.S.
production has been under 1 million pounds a year (NAS, 1975).
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123
II. METABOLISM
Mammalian biotransformation of BHC isomers involves the
formation of chlorophenols (trichlorophenol, tetrachlorophenol,
and pentachlorophenol) , which arc excreted free and as conjugates
of sulfuric and glucuronic acids (Grover and Sims, 1965; Freal
and Chadwick, 1973). Freal and Chadwich (1973) hypothesized that
Lindane is metabolized in the rat through a
pentachlorocyclohexene to a series of trichlorobenzenes and
tetrachlorobenzenes en route to the corresponding chiorophenols.
In later work, however, Chadwick et al. (1975) established that
Lindane is initially metabolized to a hexachlorocyclohexene
intermediate, from which two tetrachlorophenols and three
trichlorophenols are later derived. This mode of metabolism is
apparently peculiar to the y-isomer. Freal and Chadwich (1973)
showed that pretreatment of rats with BHC isomers resulted in
enhanced metabolism of Lindane to the chlorophenols; the effects
decreased in the order «>6>T»p.
Metabolism of isomers other than -jr-BHC leads to
trichlorophenols, not all identical with those formed from the j-
isomer; but apparently no tetrachlorophenol occurs. Mercapturic
acid excretion has also been observed after administration of
BHC isomers. This may be due in part to the glutathione-
dependent dechlorination of chlorobenzenes otherwise formed
during BHC degradation, which then gives rise to the
chlorophenols (Freal and Chadwick, 1973) . Portig et al. observed
the direct glutathione-dependent conversion of «-BHC to a
hydrophilic metabolite by a preparation of rat liver cytosol.
This is similar to the known biodegradation of r~BHC in insects,
which is glutathi one-dependent (Ishida and Dahm, 1965) ; the
insect enzyme acts on a-BHC more readily than on y-BHC, and the
p-isomer is nonreactive. The mammalian enzyme activity is
increased after pretreatment of the rat with a-BHC (Kraus et al. r
1973) . Pentachlorobenzene and pentachlorophenol have so far been
observed only as metabolites of Lindane in the rabbit (Karopolly
et al., 1973). The eliminated products, the free and conjugated
chlorophenols, are much less toxic than the parent isomers, and
some are being considered separately as contaminants in water.
III. HEALTH ASPECTS
A. Observations in Man
Surveys of human tissue for organochlorine insecticide residues
frequently show the presence of the most persistent, the ^-isomer
of BHC. In a study on the concentration of organochlorine
residues in fat and liver of terminal patients, the only BHC
isomer noted was the beta. Its concentration in cancer patients
did not differ significantly from that in people dying from
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124
infectious or other diseases (Fadomski et al., 1968) . chronic
liver damage (cirrhosis and chronic hepatitis) has been found, in
liver biopsy, in eight workers heavily exposed to BHC, DDT, or
both for periods ranging from 5 to 13 years. As far as was
feasible, other conditions, such as alcoholism, were excluded as
the cause of the cirrhosis (Schuttmann, 1968).
Over 30 cases of exposure to BHC or lindane and 21 cases of
exposure to BHC and DDT followed by the development of aplastic
anemia have been reported in the literature (Loge, 1965; west,
1967; Wood1iff et al., 1966). No satisfactory animal model of
that condition has been found and, despite efforts to study the
question, a firm causal relationship between Lindane or technical
BHC exposure and aplastic anemia cannot be stated. Development
of leukemia after Lindane exposure was reported for two cases
(Jedlieka, 1958). That causal relationship is also inconclusive
in relation to insecticide exposure.
B. Observations in Other Species
Acute Effects. Lindane is the most toxic of the isomers of
BHC. It excites the central nervous system, producing
hyperirritability, incoordination, convulsions, and death due to
respiratory collapse. Its single-dose oral LDSO in rats is 88-
300 mg/kg (Gaines, 1969; Riemschneider, 1949; Burkatskaya, 1959;
Slade, 19*15; Klosa, 1950; Woodward and Hogen, 1947; copper et
^., 1951). The oral LD50 of technical BHC is 600-1,250 mg/kg;
those of the other isomers are about 1,500 mg/kg (a) 2,000 mg/kg
O), and 100 mg/kg (6) (Riemschneider, 1949; Burkatskaya, 1969;
Slade, 1945; Klosa, 1950; Coper, 1951). The wide range in
observed LDso f°r Lindane presumably results from differences in
rates of absorption of various preparations of the material and
variations in rates of detoxification and excretion under
different experimental conditions, single oral doses of 10-25
mg/kg in corn oil were fatal to beagles (Cited in USEPA, 1973b),
and domestic animals were poisoned by similar amounts (Wasserman
et al. , 1960) .
Subchronic and Chronic Effects. Klimmer (1955) administered
daily doses of Lindane, at 32 mg/kg of body weight, by stomach
tube to male and female rats for 6 months. He observed nervous
symptoms, fatty degeneration of the liver and renal tubular
epithelium, vacuolization of the cerebral cells, and a marked
increase in mortality. None of these effects was seen with a
daily dose of 10 mg/kg during 17 months. Melis (1955) fed diets
containing Lindane at 2, 3, 4, 5, or 10 ppm for 12 months to rats
and found no abnormalities in general behavior, body weight,
histology, or other characteristics.
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125
Beagle dogs were not affected by Lindane in the diet at 7.5
mg/kg/day (Cited in USEPA, 1973b). Higher dosages produced
central nervous system effects.
Under condition of chronic administration, the y-isomer is
considerably less toxic than the other principal isomers or
technical BHC. Fitzhugh et al. (1950) conducted 2-year-rat
feeding studies with the various isomers of BHC, using diets
containing the a, 0, and -jr-isomers at 5 - 1,600 ppm. These
experiments clearly showed that the 7—isomer was the least toxic,
and the 0-isomer, the most toxic. The organs injured were the
liver and, to a lesser extent, the kidneys. In the case of
Lindane, the lowest concentration causing significant liver
changes was 100 ppm; no effect was noted below 50 ppm. Truhaut
(1954) summarized data from 2-year feeding studies in rats with
Lindane in the diet at 25, 50, and 100 ppm. At 25 ppm, no
evidence of histologic changes in the liver or kidney or any
other toxic effects were seen. At the higher concentrations,
hypertrophy of the liver was observed, and, at 100 ppm, a slight
degree of fatty degeneration. These findings and dose
relationships were confirmed by other workers (Ortega et al. ,
1957) . FAO/WHO (1967) accepted 25 ppm in the diet of rats as the
maximal concentration causing no adverse effects.
The hypertrophic liver and fatty degenerative changes of
liver at higher dosage are similar to those produced by other
slowly metabolized organochlorine compounds. As might be
expected, Lindane induces hepatic microsomal enzymes (Freal and
Chadwick, 1973) . That effect may preceed in time and dosage
relationships the liver pathology already described (Hotterer and
Schaffner, 1968) .
Mutagenicity. In a dominant lethal assay, Lindane was
administered to male mice as a single intraperitoneal dose of
125, 25, or- 50 H
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126
incidence or carcinogenicity (Fitzhugh, et al. , 1950) . In the
same study, Lindane was also administered at 5-1,600 ppm as a
solution in oil. The average life-span was significantly reduced
when all compounds were given at 800 ppm and more, but the tumor
incidence in animals receiving treatment was not greater than
that in controls (Fitzhugh et al. , 1950). However, it should be
noted that not all animals in the study underwent microscopic
examination of organs. In a further experiment in which rats
received diets containing y-BHC at 25, 50, or 100 ppm for 2
years, no significant increase in tumor incidence was observed
(Truhant, 1951) .
Prompted by epidemiologic evidence, however, and the very
high use of BHC in Japanese agriculture, more recent
investigations have been undertaken that have developed quite a
different picture. Nagasaki et al.(1971, 1972a) showed hepatoma
formation in all tested mice on diets containing technical BHC at
660 ppm; diets containing either 6.6 or 66 ppm did not produce
tumors. As expected, no hepatic nodules or tumors occurred in 11
male controls; the spontaneous incidence of liver tumors in this
strain of mice is reportedly very low.
In a later experiment, groups of male dd mice were fed the a,
0, y, or 6-isomer separately, each at 100, 250, or 500 ppm. The
experiment was terminated at 2*1 weeks. Multiple liver tumors, up
to 2.0 cm in diameter, were found in all animals given a-BHC at
500 ppm; whereas smaller nodules were found in nine of twenty
mice given 250 ppm and no lesions were found in mice given 100
ppm. No tumors were produced with any dosage of the other three
isomers or in a similar group of 20 control mice (Nagasaki et
al., 1972b).
Thorpe and Walker (1973) fed groups of male and female CF1
mice diets containing 0-BHC at 200 ppm or 7-BHC at 100 ppm. The
percentages of animals that had liver tumors were 2<»%, 73% and
93% in males and 23 percent, 43%, and 69% in females for the
controls, 200-ppm 0-BHC, and 400-ppm y-BHC diets, respectively.
Lung metastases were found in some males receiving ^- and -jr-BHC
and in some females receiving y-BHC. The incidence of other
tumors was not increased by exposure to either isomer.
Coincidentally with the Thorpe and Walker study, another
research group reported results of feeding groups of male CP/JO
mice from 5 to 31 weeks old on diets containing technical BHC,
pure «, pure ftr pure j, or a mixture of 6 and € at 600 ppm.
Liver nodules were found in all groups except the ^-group BHC
(Goto, et al., 1972) . The tumors frequently appeared to be
malignant in the case of animals administered diets containing o-
BHC and the 6- and €-BHC mixture. The findings were interpreted
as indicating that a-BHC or its metabolites are most probably
-------
1*7
carcinogenic. In the same study, three Lindane metabolites,
1,2,4-trichlorobenzene, 2,3,5-trichlorophenol, and 2,4,5-
trichlorophenol were administered for 6 months in the diet at 600
ppm; these treatments produced no hepatic tumors.
Further study by the Japanese researchers confirmed the hiah
carcinogenicity of ot-BHC and showed that combination of it with
either 0-, y- or 6-BHC had no synergistic or antagonistic effect
on the induction of tumors by a-BHC. Felated studies showed that
technical polychlorinated biphenyl (Kanechlors) promoted the
induction of hepatic tumors by a-BHC and p-BHC; mice fed 7-BHC
with or without PCB's did not show neop3astic changes in the
liver (I to et al.r 1973).
The data on induction of liver tumors by 7-BHC in mice are
seen to be somewhat contradictory. For example, Thorpe and
Walker (1973) found -jr-BHC to be somewhat tumorigenic in CFl mice
but the Japanese workers used other strains and found that they
were not susceptible to tumorigenic action by 7-BHC (Nagasaki et
al., 1971, 1972a, 1972b). The acute toxicity of technical BHC
and BHC isomers components also differs greatly among various
mouse strains; the CFl strain is particularly susceptible to
acute poisoning (Miura et al., 1974). Such toxicity differences
may be related to different rates of metabolism of BHC; if so,
the tumorigenic effects may also be so related.
The first report of tumorigenic activity of 7-BHC in rats was
made by Nagasaki et al. in 1972 . Three groups of wistar rats
(seven per group) were fed diets containing each BHC isomer at
250, 500, and 1,000 ppm. In rats sacrificed at 24 weeks, the
increased liver weight was recognized only in the 500 and 1,000
ppm groups with absence of hepatoma. At 48 weeks, one of seven
rats in the 1,000 ppm 7-BHC group showed a hepatoma, which was
1.5 cm in diameter. Three other animals of the same group showed
clear hypertrophic nodules without signs of malignant tumor, as
did other dosage and isomers groups. On the basis of these
findings, it was concluded that 7-BHC was carcinogenic in rats,
but that rats were less sensitive than mice.
A study of hepatocellular carcinoma development in rats
treated with various isomers of BKC was recently published (Ito
et al.r 1975). Male Wistar-derived rats were administered BHC
Tsoiriers in the diet for 72 weeks. Each treatment group included
18-24 animals. The dietary treatment levels were: a-BHC, 500,
1000, and 1500 pprr.; p-BHC, 500 and 1000 ppm; 7~BHC, 500 ppm; 6-
BHC, 500 and 1000 ppm. No neoplastic changes or other abnormal
findings such as oval cell infiltration, fatty changes, fibrosis,
or bile duct proliferation of the liver were observed in groups
receiving 500 ppm of any isomer, but relative liver weight was"
increased in ail groups receiving 500 ppm of any isomer, but
-------
128
relative liver weight was increased in all groups except those
treated with 500 ppm 6-BHC. Tumors developed only in the livers
of rats in groups given «-BHC. In a group treated with 1500 ppm
or-BHC for 72 weeks, the liver increased in weight due to tumor
growth; in 10 of 13 rats it had a slightly irregular surface with
many nodules up to 2.0 cm in diameter. In groups, 12 out of 16
rats that received 1000 ppm a-BHC for 72 weeks, and 5 out of 12
that received 1000 ppm <*-BHC for 48 weeks, developed liver
tumors. No metastases were seen. No liver tumors developed in
other dietary groups, and no tumors were seen in other organs of
any experimental animals.
Reproduction. Charles River C.D. rats receiving Lindane at
25, 50, and 100 ppm continuously in the diet during a three-
generation study showed normal reproduction, with respect to
litter size, breeding rate, and birth weight in all generations.
No malformations were found. The only effect observed was the
expected liver hypertrophy with hepatocyte enlargement (Cited in
USEPA, 1973b).
Teratogenicity. No available data.
IV. CARCINOGENIC RISK ESTIMATES
«-, 0-, and yBHC have produced dose-related liver tumors
when given orally to mice and rats (Ito et al., 1973 and 1975,
and Thorpe and Walker, 1973). For each compound the available
sets of dose response data were individually considered as
described in the risk section in the margin-of-safety chapter.
Each set of dose response data was used to statistically estimate
both the lifetime risk and an upper 95% confidence bound on the
lifetime risk and an upper 95% confidence bound on the lifetime
risk at the low-dose level. These estimates are of lifetime
human risks and have been corrected for species conversion on a
dose-per-surface-area basis. The risk estimates are expressed as
a probability of cancer after a lifetime consumption of 1 liter
of water per day containing Q/ppb of the compound of interest.
For example, a risk of 1X10-* Q implies a lifetime probability of
2X10-5 of cancer if 2 liters/day were consumed and the
concentration of the carcinogen was 10 ppb (i.e. Q=10). This
means that at a concentration of 10 ppb during a lifetime of
exposure this compound would be expected to produce one excess
case of cancer for every 50,000 persons exposed. If the
population of the U.S. is taken to be 220 million people, this
translates into 4400 excess lifetime deaths from cancer or 62.8
per year. Since several data sets are typically available the
range of the low-dose risk estimates are reported.
-------
123
For a-BHC at a concentration of 1 pg/liter (0=1) the upper
95% confidence estimate of risk for man would fall between 2.2 to
6.5X10-*Q.
For p-BHC at a concentration of 1 jig/liter (Q=1) the
estimated risk for man would be from 1.1 to 3.5X10-* Q. The
upper 95% confidence estimate of risk at the same concentration
would be between 2.5-5.8X10-* Q.
For Lindane at a concentration of 1 pg/liter (Q=1) the
estimated risk for man would be from 3.3 to 8.1X10-* Q. The
upper 95% confidence estimate of risk at the same concentration
would be from 5.6-13x10-*
V. CONCLUSIONS AND RECOMMENDATIONS
The chronic toxicity of the BHC isomers is clearly related to
the tumorigenic effects so far observed only in rodents. The
isomer is the most strongly implicated; its activity is
sufficient to account for the degree of hepatoma formation
observed with technical BHC administration in mice. Lindane is a
weaker turoorigen in mice, and is so far a questionable tumorigen
in the rats.
As of 1972, the FAO/WHO AEI for Lindane was set at 0.0125
mg/kg/day. Later, that value was reduced to 0.001 mg/kg/day and
held under temporary status because of the newer data concerning
carcinogenicity. A full-scale reevaluation of the chronic
toxicity of Lindane is scheduled for 1977 by the FAO/WHO. The
EPA has recently announced plans to issue a presumptive notice
that Lindane is too hazardous for continued registered use, with
the intention of reevaluating its administrative position on this
insecticide.
In light of the above and taking into account the
carcinogenic risk projections it is suggested that very strict
criteria be applied when limits for EHC isomers are established.
The available chronic toxicity data are summarized in Table VI-
26.
-------
TAILC VI-26. gumi«ary of Chronic Tonieiev fata tor liic
DM OK* t*v«lft
illftlieit no-fldverae
affect levol or
Ctiamiaal fona and
f fll pal ftMlaa
MI
IRC (ttch)
?-IIIC, -IHC
-IHC
r-IHC
m (JOM,JOF;CFI atraln)
400 p|im (VVM(29F;C1'1 atraln)
600 ppm f20M;KR-JCL atrain)
600 ppm l;lCR-JCI. atraln)
300,600 ppm
5L, 100. 250 pprn (JOM.dd strain)
SO, 100. 250 ppm (JUM.dd strain)
50,100,250 ppm (3UM,dd strain)
12.5.2^,50 ppm (? ;NMRI strain)
lowest minimal
•fleet level
100 ppm
100 ppm
800 ppn
iOOpp*
500 ppm
300 ppm
300 ppm
1000 ppm
660 ppm
230 ppm
300 ppm
300 ppm
200 ppm
400 ppm
600 ppm
600 ri>m
600 ppm
600 ppm
300 ppm
100 ppm
250 ppm
250 ppm
50 ppm
EffMt maaaurad
Kaduead llftapan, M
Incraaaad tumor ineldanea
No Incrcaia In tumor
Incldanca
Llvar hypartrophy (nodular
hyparplaila, carcinoma at
1000 and 1300 ppm)
Llvar hypartrophy
Llvar hypertrophy
Liver hypertrophy
Htpatown (20/20)
Hepatic nodulei (9/20),
Tumors at 500(20/20)
No adveraa efftct
No advene effect
Hepatic tun.prd, lung
molaita»es
Hepatic tuition, lung
m«tasta»ei
Hepatic nodulaa, tumors
Hepatic tumors, Jung
Hepatic tumor*, lung
Hepatic t-imora, lung
No advene effect
Llvar hypertrophy (hyper-
platla, tumors at 250)
Liver hypertrophy
Liver hypartrophy(sllght)
No adverse eHect
liltranco
Fltihu|h, et al
1930 ^^
Truhaut 19S4
Ito
1973
Nagasaki ft ^.
1971 1972a
Nagasaki «t al.
1972b
Thorpe &
Walker 1975
Goto, at fl..
1972
Herbat,
1975
These coaipounds are animal carcinogens.
o
-------
PENTACHIOROPHFNOI
I. INTRODUCTION
Pentachlorophenol (PCP) has been uned sine-? 1936 for wood
preservation (Spencer, 1973). Domestic production of TCP is
estimated at U6 million pounds .1 year (national Academy of
Sciences, 1975) .
PCP is produced commercially by the chlorination of phenol
(Spencer, 1973). Commercial-grade TCP contains 88.U* PCP, 1.U?
tetrachlorophenol, 6.2% higher chlorinated phenoxyphenol^, less
than 0.1% trichlorophenol, and various dihenzo-jg-dioxins and
dibenzofurans (Johnson et al. , 1973; Schwetz et al., 197U) . The
highly toxic tetrachlorodioxins are not found in tpchnical PCP.
PCP is soluble in water at 20 ppm at 30°C. It is not very
volatile, as evidenced by a vapor pressure of 1.1 x 10-* mm Hg ar.
20°C (Spencer, 1973). Concentrations of 0.70 and 0.06 nob PCP
havf been observed in river and treated drinking water,
respectively (Buhler et al.. , 1973) . The highest concentration ot
PCP reported in United States drinking water was L. 4 ppb (EPA,
1975e).
II METABOLISM
A pharmacokinetic profile ol pentachlTOphenol in monkf vs and
an elimination study with f »'Clpent.achlorophenol and its
metabolites in rats have been conducted (sutmitt-pd for
publication in Toxicol. Appl. Pharmacol.) . The^e studio
that 90% of a 10 mg/kg dose of TCP in rats is pliminatod rnp
with i half lite of from 13 - 17 h de-pending on SFX. PCP IF;
excreted either as tett achlorohydroguinonc (Ib1*) or as a TCP
glucuronide conlugate in the urine (9S) or a tree PCP (75%).
excretion pattern in monkeys was slower than in ratr and almost
all pep was excreted unchanged in urine. It was sncrgested that
the monkey may be a better animal model and more closnly
approximate human pharmacokinetics.
III. HEALTH ASPECTS
A. Observations In Man
M«=non (1958) reported loss of appetite, r^snirat-orv
difficulties, anesthesia, hyperpyr-^xia, sweating, dyspnea, inci
rapidly progressive coma in humans exposed to PCP.
•A. number of cases of human poisoning ty PCP are reviewed bv
Armstrong et, al. (1969) . The miniwum lethal dore for humans
estimated to be 29 mg/kg (The Toxic Substances List, 1974).
-------
done in Russia has established a maximum permissible
concentration of i»0 ng/m3 PCP in the air (Tatakova, 1969)
B. Observations In other Species
&cute effects. The acute, oral LDsos for PCP are: 120-140
mg/kg for the mouse, 27-100 mg/kg for the rat, 100 mq/kq for the
guinea pig, 100 - 130 mg/kg for the rabbit, and 150 - 200 mg/kq
for the dog (Christensen et al.. 1971; Deichmann et al., 1942;
Knudsen et a_l. , 1974; McGavack et al., 1911; Stohlman, 1951. The
acute symptoms of intoxication are vomiting, hyperpyrexia,
elevated blood pressure, increased respiration rate, and
tachycardia. The LDSO after oral administration of PCP to male
and female rats was 146 and 175 mg/kg and upon percutaneous
exposure 320 and 330 mg/kg, respectively (Cannes, 1969) .
Subchronic and chronic effects. In a study to determine the
subchronic toxicity of the compound, FCP was fed in the diet to
groups of wistar rats at concentrations of 0, 25, 50, and 200 ppm
for a 90-day period (Knudsen et a_l., 1 S74) . Female rats
receiving 200 ppm (10 mg/kg/day) PCP showed a reduced growth rate
while liver weights were increased in male rats ingestinq 200 and
50 ppm (2.5 mg/kg/day). After 6 weeks, rats fed 50 and 200 pom
PCP showed elevated hemoglobin and hematocrit values whereas at
11 weeks, hemoglobin and erythrocytes were significantly reduced
in the same groups of animals. No PCP related effects were seen
in animals fed 25 ppra (1.25 mg/kg/day). In another experiment,
male rats received 1,000 ppm (50 mg/kg/day) of t-pchnical or pure
PCP for a 90-day period (Kimbrough and Linder, 1975). Both PCP
samples caused an increase in liver weight. Much more severe
histopathological changes occurred in the livers of rats-given
the technical PCP than in those given the pure PCP. in another
90 day study, Sprague-Dawley rats showed increased liver and
kidney weights, elevated serum alkaline phospnatase, and
depressed serum albumin levels in animals consuminq 3 mq/kq/day
of technical PCP (Johnson et al., 1973). When a sample of
improved PCP containing substantially reduced amounts of dioxins
was fed to rats, no adverse effects were seen at 3 mg/Vq/day- in
animals receiving chemically cure PCP, kidney and liver weights
were elevated at 30 and 10 mg/kg/day, respectively, but 3
wq/kg/day was without adverse toxicoloqic effect.
In a chronic study, liver weights were siqnificant.lv
increased in rats ingestinq 500 ppm (25 mg/kq/day) technical PCP
over an 8 month period (Kimhrough and Linder, 1975). No toxic
effects were observed at 100 ppm (5.0 mg/kg/day) PCP.
*
When female weanling rats were fed pure or technical Prp for
8 months, increased urinary porphyrin excretion and increased
liver porphyrin levels were observed in animals fed 100 (5.0
-------
133
mq/k j/day) or 500 ppm ot the technical product (roldstrin ^1 -li- '
1976) . None of the rats fed pure PCP became- pornhyi'ic. T.ivr-r
weights were increased in rats t <>ceiviin SCO pom (25 ma/kq/day)
of technical Pep but wer«; unchanged in animals fed riOO ppm of th"
pure phenol . Thus the porphvrin a°d other major liver changes
induced by technical FTP are apparently due to cont aminants,
probably the chlorinated dibenzo-£-dioxins, rather than PCP.
proved negative in the rex-linked l^vel
test in Drosophila (Vogel and Chandler, 197U).
Carcinogenicity- No available data.
Te JL a tqq_eni^c_i ty. In a study to examine the potential
tr ra to-Tonirrity of PCP, purified and commercial qrade i^CP wer<=
administered to Spraque-Dawley rats on days 6 - 15, 3 - 11, and
12 - 1'< of gestation (Schwetz et al. , 197U). PCF was embryotoxi'-
and fetotoxic at doses of the commercial and pur< phenol of 15
mq/kq and above. The no adverse1 effect dose lev< 1 was 5 ma/kq
for th- commercial PCP, but at this same dor - level, delayed
o:-.:- i f i • • it i on of * he skull was observed aft^r t r <-ure
PCP.
Oral administration of 0, 1.25, 2.5, 5, 1C, ami 20 mq/kq Pc^
to hamsters on days 5-10 of g< station produced fetal death
and/or resorp'ions at 5 mq/kq/day and abo''*-- (HinUr, 1973).
HI. cmqc! ":>T ONf' Ann HFCO^MtNDATICNr,
'T.-i-i'^ are ;,!ibstanf ial 1 i saqi eement s in the r^siilt - of r«vra!
o< flu mi acut • innio tcxi<-ity exrerlment-s wiMi PCP (T.ilil*
•|i f , . .fhar1": L' • •'ins''-.- of t-h? use of i nadeaua^ e!ly char .-i<;t er iz-^d ^Cp
pi(-paraf ions in th"£.-e ^.; t.uil i.'T.. In addition, ^wo year chronic-
toxicity expcrriM- nts in on« or more species have not yet been
conducted with this extensively used chemical. High doses (>5
mu/kq/day) of POP hav<=- been, shown to be teratogenic in rats and
hamsters when ad,nini st ^red durit.q susceptible davs of aegta<-ion.
There is also -• need for an adequate; determination of the
carcinoqr-nic nn tont ia J. o! this chemical.
On t hc' las'-.- ^>f 4 h^ iva;lalle chronic toxicity <°ata an
for pentachlorof henol has been calculated to be O.fo.}
Hie d i t-a and c.< •'l cula t i ons ate rummarizrd in TabU- VI-55.
-------
1 34
TABLE VI-55. Summary of Chronic
TtHdclty Data for Bsntachlorophenol
Dosage Levels and
Duration Ho. of Animals per
Species of Study Group
Rat 12 weeks O-200 ppm in diet,
20 animals per
group
Hamster days 5-10 1.25-20 rag/kg/day
orally
Rat
Rat
Rat
Rat
Rat
90 days 0-30 rag/kg/day in
diet"
90 days 0-30. mg/kd/day in
diet"
days 6-15 0-50 mg/kg/day,
orally, 20-20
animals per group
8 months
0-50 ppm in diet,
2O animals per
group
Highest no-adverse
effect Level or Lowest Effect
Minimal-effect Level Measured
Reference
25 ppm (1.25 mg/kg/day) No toxic Knudson et al. ,
effect 1971*
8 months 0-500 ppm in diet
2.5 meAg/day
e
3 mg/kg/day
3 mg/kg/day
5 mg/kg/day
100 ppm
(5.0 mg/kg/day)
500 ppm
(25 mg/kg/day)
No fctotoxic Hinkle, 1973
or cni.ryo-
toxic eff-cts
No toxic
effect
Johnson et al.,
1973
Increased Johnson et al. ,
orf;?ui weights, 1973
serum enzyme
Terato-r^enic Schwetz et al. ,
effects 1971*
No toxic
effect
No toxic
effect
Kimbrough and
Linder, 1975
Goldstein et al.,
1976
Using an uncertainty factor of 1,000, suggested no-adverse-effect level in
drinking water is calculated as follows:
3 « 0.003 mg/kg/day (ADI), 0.003 x 70C x O.ld « 0.021 mg/liter.
1,000
pure pep
technical pep
°Assume average weight of human adult « 70 kg.
dAssume average daily intake of water for man - 2 liters, and that 20$ of total intake
is from water.
CTest study from which to calculate suggested no-adverse-effect level.
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PHENYLACETIC ACID
I. INTRODUCTION
Phenylacetic acid is derived from benzyl cyanide. It is used
in the manufacture of perfume, medicines, penicillin, fungicides,
plant hormones, and flavorings (Chem. Diet. 1S72) . Phenylacetic
acid is slightly soluble in cold water. Of the 10 water supplies
surveyed by the EPA (1975a) , only the finished water of Seattle
contained phenylacetic acid, at U pg/liter. (NOPS, EPA 1975a).
II. METABOLISM
Phenylacetic acid and alkyl chloro derivative are rapidly
absorbed from human buccal tissues or membranes. Phenylacetic
acid inhibits the activity of coenzyme A. At 0.5 - 1 mM/kg, it
inhibits the acetylation of sulfanilamide (Lisunkin, 1965).
III. HEALTH ASPECTS
A. Observations In Man
The adverse health aspects of phenylacetic acid have not been
examined in man.
B. Observations In Other Species
Acute effects. The oral LD50 of phenylacetic acid is 1,630
mg/kg in rats. In a study of the acute effects in mice,
intraperitoneal injection of 300 mg/kg proved toxic; 11 of the 15
experimental animals died (Anderson et al.r 1936). The time to
death varied from 10 minutes to 10 days.
Chronic effects. No available data.
Mutagenicity. No available data.
Carcinogenicity. Hoshino (1970) reported that phenylacetic
acid~~did not promote tumor formation when the compound was given
to rabbits intravenously and subcutaneously for UO days.
Teratogenicity. In a teratogenic study with rats, the
administration of phenylacetic acid on the twelfth day of
embryogenesis affected body weight, retarded skeletal
ossification, and caused embryos to be resorbed at twice the rate
of controls. The dosage was 0.2% of the LD50, or 3.2 mg/kg
(Anderson et al., 1936).
-------
IV. CONCLUSIONS MID RECOMMENDATIONS
In view of the relative paucity of data on the mutagenicity,
carcinogenicity, teratogenicity, and long term oral toxicity of
phenylacetic acid, estimates of the effects of chronic oral
exposure at low levels cannot be made with any confidence. It is
recoHMended that studies to produce such information be conducted
before limits in drinking water can.be established.
-------
r? n
o r
PHTHALIC ANHYDP.IDE
I. INTRODTJCTION
Phthalic anhydride is used in the manufacture of
plasticizers, alkyl and polyester resins, synthetic fibers, dyes,
pigments, Pharmaceuticals, and insecticides (EPA, 1975d). The
United States production of this compound in 1973 was over 1
billion pounds (USITC, 1975) . It is soluble at 1 part in 162
parts of water (Merck Index, 1968) . It has been detected in
finished water (EPA, 1976).
II. METABOLISM
Phthalic anhydride is apparently excreted largely unchanged
by both animals and man. In man and dogs, the unchanged compound
can be recovered in urine almost quantitatively (Williams, 1959) .
There is no firm evidence that phthalic anhydride is converted to
phthalic acid in the body; if it is, it should occur as the acid
in urine.
III. HEALTH ASPECTS
A. Observations In Man
In man, phthalic anhydride is an eye, skin, and mucous-
membrane irritant (Friebel, 1956; Merlevede and Elskens, 1957;
Baader, 1955; Menshick, 1955; Chezzi and Scotti, 1965) .
B. observations In Other Species
6. gf fegts. Fassett (1963a) recorded the acute oral LD50
as 8CK)~ 1,600 mg/kg in rats and less than 100 mq/Kq in guinea
pigs. Vapor exposures, particularly to heated phthalic
anhydride, produced congestion, irritation, and injury of lung
cells (Friebel, 1956). Jacobs et a3 . (19UO) reported that the
compound sensitized the skin of guinea pigs. Freibel (1956)
reported a study in which oral doses in rats (starting at 20
mg/kg/day) were doubled weekly; 0.89 g/kg was reached by the
ninth week. Rats that died at the high dosage had severe
nephrosis, with destruction of the tubular epithelium. Surviving
animals had gastric ulceration.
Chronic effects. No available data.
Mutagenicity. No available data.
Carcinogenicity. No available data.
Teratogenicity. No available data.
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TOXAPHENE
I. IMTRODDCTION
Toxaphene, a complex Mixture of largely uncharacterized
chlorinated camphene derivatives, is the nost heavily used and
least understood organochlorine insecticide. The Major reason
that so little is known about either its structure or its
Metabolism is its coMplex nature: it is a Mixture of at least 175
compounds, of which the structures of fewer than 10 are known
(Casida, et al. 1974).
Toxaphene is widely used as a foliage insecticide on a
variety of food, feed, and fiber crops (USEPA, 1974c). A
tolerance of 7 ppm was established in 1950 for a variety of
crops. More recently, tolerances of 5, 3, and 2 ppm have been
established for small grains, for cotton seed, and for bananas
and soy beans, respectively. In addition, there is a temporary
tolerance of 7 ppm for residues in or on sugar beets and
sunflower seeds. Similar foreign tolerances have also been
established. A tolerance of 7 ppm for residues of Toxaphene in
the fat of meat has also been established. Other regulations
have established interim tolerances for Toxaphene residues in or
on alfalfa at 1 ppm and in milk at 0.05 ppm.
Like many organochlorine insecticides, Toxaphene is known to
h^ somewhat persistent in the environment, particularly in soil.
The EPA has set an interim standard for Toxaphene in finished
water for 0.005 mg/liter (C»«H*°Cl»-Technical chlorinated
camphene, 67-69% chlorine) (USEPA, 1975i).
II. METABOLISM
Very little is known about the metabolism of Toxaphene in
animals. In the rat, 52.61 of an oral dose of [»*Cl]Toxaphene
was excreted within 9 days (Crowder and Cindal, 197U).
Approximately 37* was found in the feces, and 15* in the urine.
On extraction. Most of the radioactivity occurred in the water
fractions of urine and feces as ionic chloride. Animals given a
second dose on the ninth day excreted Toxaphene in a similar
Manner, except that chlorine-36 excretion in feces was reduced.
Less than 10% of the dose was found in selected tissues and
organs 1 day after treatment.
Toxaphene has been found in milk of dairy cows given 20-140
ppm in the feed (Clayborn et al., 1963). At lower
concentrations, Zweig et al. (1963) reported that the amount of
toxaphene in milk was less than 0.03 ppm. When the animals were
removed from the toxaphene diets, the milk became uncontaminated
within 2 weeks.
-------
III. HEALTH ASPECTS
A. Observations in Man
Although some cases have been reported, acute Toxaphene
poisoning in humans is rare. When Toxaphene was introduced, four
cases of poisoning by ingestion in children under 4 years old
were reported (McGee et al«r 1952). The same study contained a
description of severe toxaphene poisoning in adults after its
misuse in agriculture. The authors estimated that three patients
ingested toxaphene at 9.5 - 17 mg/kg.
Aside from accidental poisoning, human volunteers have
participated in Toxaphene toxicity studies. In one study, 50
human volunteers inhaled mist containing Toxaphene at 0.0004
mg/liter for 10 min/day for 15 days; there were no subjective or
objective results (OSEPA, 1974C). In another study, a mist
containing Toxaphene at 0.25 mg/liter of air was inhaled by 25
people for 30 min/day for 13 days; there was no evidence of local
or systemic toxicity (USEPA, 1974c) .
B. Observations in Other Species
Acute .Effects. Acute toxicity studies with Toxaphene have
involved oral, dermal, intravenous, intraocular, and inhalation
exposure. The toxicity of toxaphene is influenced by the solvent
or vehicle used. When administered orally as a solution or
emulsion, it is more toxic in a digestible vegetable oil than in
an oil like kerosene. Toxicity of Toxaphene by skin absorption
is much less from an inert dust than from an oily solution. The
acute oral LD50 is 90 mg/kg in male rats and 80 mg/kg in female
rats; the acute dermal LD50 is 1,075 mg/kg in male rats and 780
mg/kg in female rats (Gaines, 1960).
Administration of a 20% solution of Toxaphene in kerosene to
the eyes of rabbits and guinea pigs for 14 consecutive days
produced mild irritation of the eyelids with loss of hair around
the eyelids. The eyes were not injured, and the irritation in
the eyelid was abated within 10 days (USEPA, 1974c) . In acute
inhalation studies, 40X Toxaphene dust at 3.4 g/liter of air
killed approximately ha^f the exposed rats within 1 h.
Subchronic and Chronic Effects. Ortega et al. (1951) have
studied the subchronic toxicity of Toxaphene in small groups of
rats fed 50 and 200 ppm in the diet for 9 months. No clinical
signs of toxicity or inhibition of food consumption or growth
rate were evident. However, only the liver, spleen, and kidneys
were examined histologically. There was no apparent damage to
the kidneys or spleen, but 3 of the 12 rats that received 50 ppm
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showed slight liver changes, and 6 of the 12 rats fed 200 ppm
showed distinct liver changes.
Degenerative changes in the kidney tubules and liver
parenchyma have been reported in dogs fed Toxaphene at low
dosages (Lacky, 19*19); two dogs received 1 mg/kg/day (about 160
ppm) for 14 days, and two others received the same dosage for 106
days.
Chronic studies have been done in rats, guinea pigs, dogs,
cattle, sheep, and rabbits. In rats fed at 25, 100, and 400 ppm
in the diet for the conventional 2-year period, only the liver
showed significant changes, at 100 and <»00 poir. (Fitzhugh and
Nelson, 1951).
Toxaphene was administered daily to dogs in a dry diet for 2
years. When it was fed at *IO ppm, there was slight degeneration
of the liver; at 200 ppm, there was moderate degeneration of the
liver(USEPA, 197«c).
Studies have also shown that, when Toxaphene is applied to
the skin of many large animals (including cattle, sheep, goats,
horses, and swine), adult animals can withstand higher dosages
than immature animals. Also, applications of cotton patches
treated with Toxaphene to the skin of 200 subjects caused no
primary irritaion or sensitization.
Reproduction, Teratogenicity, Carcinogenic!ty, and
Mutagenicity. A three-generation reproductive study was
conducted, according to currently accepted protocol for rats,
with Toxaphene at 20 and 100 ppm (Kennedy et al., 1973). No
differences between control and Toxaphene-treated animals were
reported, with respect to reproduction, performance, fertility,
lactation, or viability, size, and anatomic structure of progeny.
In mutagenicity studies, occurrence of mutagenic effects among
the controls and the animals treated with Toxaphene were similar.
No evidence of carcinogenic action was reported in any of the
chronic-toxicity studies previously undertaken.
IV. CONCLUSIONS AND RECOMMENDATIONS
Toxaphene is a widely used organochlorine insecticide that
apparently has not caused a great deal of environmental harm,
although it has been used in agriculture for many years. Because
it is a complex mixture of uncharacterized camphene derivatives,
very little is known about its metabolism in plants or other
higher organisms. Considerable information is available,
however, on its toxicity in laboratory animals and various
aquatic organisms. An ADI at 0.00125 mg/kg/day v?as calculated on
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141
the basis of the chronic toxicity data. The available toxicity
data and calculations of ADI are summarized in Table VI-28.
A summary of the results of examination of over 100,000
samples of raw agricultural commodities by the FDA between 1963
and 1969 (Duggan et al., 1971) shows that Toxaphene residues are
seldom present. Thus, the possibility that large quantities of
Toxaphene residues could be found in drinking water is not great.
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TABLE VI-28: Summary of Chronic
Oral Toxlcity Data for Toxaphene
Species
Duration
of Study
Dosage Levels and
Ho. of Animals per
Croup
Highest
So-Adverse-Effeet
Level or Lowest- Effect
Minimal Effect Level Measured
Re f erence
Rat 9 months 50 ppm (12 animals)
Rat 9 months 200 ppm (12 animals)
Oog 44 ('ays 160 ppm (2 animals)
I>og 106 days 160 ppm (2 animals)
Rat 2 years 25 ppm, 100 ppm 25 ppm (1.25 mg/
and 400 ppm kg)c,d
100 ppm
sliRht liver
change in
aninals
Distinct
liver
change in
6 animals
Change in
kidney
tubules
and liver
parenchyma
Ko adverse
effect liver
change
Ortega
ct al. ,
1951
Ortega
et al.,
1951
Lackey ,
1959
Lackey,
1949
Fitzhugh
and
Nelson, 1*51
Using an uncertainty factor of 1,000, suggested no-adverse effect level In drinking water
is calculated as follows:
• O.OC125 mg/kg/day (ADI). 0.00125 x 70a x O.lb - 0.0086 mg/llter.
'Assume average weight of human adult - 70 kg.
^Assume average daily Intake of water for man - 2 liters, and that 201 of total intake is
from water.
cTest study from which to calculate suggested no-adverse-effect level.
dAssume weight of rat - 0.4 kg and average daily food consumption of rat - 0.02 kg.
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143
BENZO(a)PYRENE
I. INTRODUCTION
Benzo(a)pyrene is a ubiquitous polycyclic aromatic
hydrocarbon that is produced largely, if not exclusively, in the
pyrolysis of naturally occurring hydrocarbons. It was isolated
early in pure form from coal tar, one of the so-called industrial
carcinogens. Benzo (a) pyrene is found as a constituent in coal,
petroleum, shale, and kerosene. It has been reported that it is
present in the combustion products of fuels and cigarette smoke.
Benzo (a) pyrene is very persistent in water and is soluble at
O.OOU mg/liter at 27°c' (Davis, 1942) . It has been detected in
finished water (EPA, 1976).
II. METABOLISM
The primary routes of benzo (a) pyrene excretion in mice and
rats are the hepatobiliary and gastrointestinal tracts. The
dihydroxy-, 3-hydroxy-, and 6-hydroxy- derivatives have been
found in the liver, bile, and bowel (Berenblum and Schoenthal,
1913; Falk et al., 1962; Sims, 1967, 1970a,b).
III. HEALTH ASPECTS
A. Observations in Man
There is no firm evidence that benzc(a)pyrene alone produces
toxicity, including teratogenicity, mutagenicity, or
carcinogenicity in humans. On the other hand, mixtures of
compounds which contain benzo (a)pyrene as a constituent have been
associated with cancer in man. In such cases the exact role of
benzo(a)pyrene is difficult to assess
B. observations in Other Species
Mutagenicity. Although there is no substantive literature on
the mutagenic effects of benzo (a)pyrene, there have been
indications that its metabolites bind to DNA. Eenzo (a) pyrene is
a positive mutagen in the SaImone1la/microsome test (McCann et
al., 1975).
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144
Carcinoqenicity. The effects of benzo(a)pyrene have been
examined for the most part in relation to carcinogenesis. In
mice, a single oral 0,012-mg dose induced forestomach tumors
(Pierce, 1961); in rats a single 100-mg dose (gavage,) produced
mammary tumors (Huggins and Yang, 1962). Single subcutaneous and
intramuscular doses that induced tumor formation were 0.062 mgr
0.004 mg, and 0.0025 mg in C3II, C57, and CFW Swiss mice,
respectively. In rats and hamsters, the parenteral carcinogenic
doses were 0.05 mg and 0.01 mg, respectively.
In chronic oral studies, carcinogenic effect? were observed
in mice after the administration of benzo (a) pyrene at 40-*»5 ppm
for 110 days (Figdon and Neal, 1966, 1969) . Oonetenwill and Mohr
(1962) reported stomach tumors in hamsters after biweekly oral
administration of the compound for 1 month,, in mice, chronic
dermal administration of a 0.001% solution three times a week
induced benign and malignant skin tumors (Wynder et al., 1957).
Rats and hamsters were also shown to be sensitive to the
induction of skin tumors with benzo(a)pyrene (Nakano, 1937;
Shubik et al., 1960).
In a study of the transplacental carcinogenic effects of
benzo(a)pyrene, 2-U mg on days 11, 13, and 15 of pregnancy
induced tumors in the offspring of treated mice (Bulay and
Wattenberg, 1970; Bulay, 1970). No other abnormalities were
observed.
Teratogenicity. Rigdon and Rennels (196U) found one
malformed fetus out of 7 litters of rats whose mothers had been
exposed to benzo[ajpyrene at a level of 1 mg/g of diet during
pregnancy. There were also many excess reabsorptions and dead
fetuses.
IV. CARCINOGENIC RISK ESTIMATES
Numerous carcinogenesis studies have been conducted in
rodents with oral administration of benzo(a)pyrene (IARC, 1973).
Stomach tumors in mice have been observed in several studies, as
well as leukemia and lung adenomas. In rats, mammary tumors and
papillomas in the esophagus and forestomach have been found. In
hamsters, tumors were found in the forestomach, esophagus, and
intestine. No satisfactory human data are available.
In the above studies, the oral administration of
benzo(a) pyrene showed evidence of dose-response relationships.
However, it was generally fed for less than 6 months; this is not
adeauate for estimating lifetime effects. Thus, without specific
biologic assumptions that relate short-term to lifetime effects,
ro reasonable risk estimates can be attempted.
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145
V. CONCLUSIONS AND RECOMMENDATIONS
The occurrence of upper gastrointestinal tract tumors in
animals fed benzo(a)pyrene, skin tumors at sites painted with it,
and subcutaneous sarcomas at sites where it was injected
demonstrates that benzo(a)pyrene is a potent contact carcinogen.
In light of the above it is suggested that strict criteria be
applied when limits for benzo (a) pyrene in drinking water are
established. The available chronic toxicity data are summarized
in Table VI-46.
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TABLE VI-46. Suanary of Chronic
Toxieity Data tor Benzo(a)Pyrene
Species
Moose
Hamster
Moose
Rat
BBMter
Dosage Levels and
Duration No. of Animals per
of Study Group
110 days
1-5 mo. biweekly adminis-
tration
130 days weekly paintings,
15 animals
Uo wks . biweekly paintings ,
10 Animals
Highest No-adverse-
effect Level or Lowest
Minimal-effect Level
UO-U5 ppm
(oral)
2-5 mg
(oral)
0.001^6 solution
(oral)
0.5-1^ solution
0.01^ solution
Effect
Measured Reference
Stomach Rigdon & Neal^
tumors 19^5, 1967,
1969
Stomach Donetenwill &
tumors Mohr, 1962
Malignant Wynder et a!0
skin tumors 1957
Skin tumors Nakano, 1937
Skin tumors Shubik et al.^
I960
(This compound is a suspected human carcinogen as well as a confirmed
animal carcinogen.)
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