EN DOS UL FAN
Ambient Water Quality Criteria
Criteria and Standards Division
Office of Water Planning and Standards
U.S. Environmental Protection Agency
Washington, D.C.
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CRITERION DOCUMENT
ENDOSULFAN
CRITERIA
Aquatic Life
For endosulfan the criterion to protect freshwater aquatic
life as derived using the Guidelines is 0.042 ug/1 as a 24-hour
average and the concentration should not exceed 0.49 ug/1 at any
time.
For saltwater aquatic life, no criterion for endosulfan can
be derived using the- Guidelines/ and there are insufficienr data
to estimate a criterion using other procedures.
Human Health
For the protection of human health from the toxic properties
of endosulfan ingested through v/ater and contaminated aquatic organisms,
the ambient water criterion is 0.1 mg/1.
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Introduction
Endosulfan is a broad spectrum insecticide of the group
of polycyclic chlorinated hydrocarbons called cyclediene in-
secticides. It was discovered and developed in 1954 by
Farbwerke Hoechst AG. in Germany and introduced under the
registered trademark Thiodan. The trade names of endosulfan
include Beosit, Chlorthiepinr Cyclodan, Insectophene, Kop-
Thiodan, Malix, Thifor, Thimul, Thioden, and Thionex (Berg,
1976).
Annual production of endosulfan in the United States was
estimated in 1974 at three million pounds. It is presently
on the Environmental Protection Agency's restricted list
which limits its usage. However, significant commercial use
of endosulfan for insect control on vegetables, fruits, and
tobacco continues.
Endosulfan has been demonstrated to be highly toxic to
fish and marine invertebrates and is readily adsorbed by
«
sediments. It therefore represents a potential hazard in the
aquatic environment.
Endosulfan is a light to dark brown crystalline solid
with a terpene-like odor, having the molecular formula
CgClgHgC^S, a molecular weight of 406.95, and a vapor pressure
of 9 x 10~3mm Hg at 80°C (Brooks, 1974; Whetstone, 1972).
It exhibits a solubility in water of 60 to 150 u.g/1 and is
readily soluble in organic solvents (Braun and Frank, 1973).
The chemical name for endosulfan is 6,7,8,9,10,10-hexachloro-
1,5, 5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzod ioxathiepin-3-
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oxide. It is prepared through the Diels-Adler addition of
hexachlorocyclopentadiene with cis-butene-l,4-diol to form
the bicyclic dialcohol, followed by esterification and cycli-
zation with SOC12 (Windholz, 1976).
Technical grade endosulfan has a purity of 95 percent
and is composed of a mixture of two steroisomers referred to
as alpha and beta or I and II. It has a melting point range
of 70 to 100°C and a density of 1.745 at 20°C (Burchfield and
Johnson, 1965). The endosulfan isomers are present in the
*
ratio 70 percent isomer I to 30 percent isomer II. Impuri-
ties present in technical grade endosulfan consist mainly of
the degradation products and may not exceed two percent endo-
sulfandiol and one percent endosulfan ether. Endosulfan is
commercially available in the form of wettable powders, emul-
sifiable concentrates, granules, and dusts of various concen-
trations (Berg, 1976). It is a powerful contact and stomach
insecticide used to control a wide spectrum of insects.
Endosulfan is stable to sunlight, but is susceptible to
oxidation and the formation of endosulfan sulfate in the
presence of growing vegetation (Cassil and Drummond, 1965).
Technical grade endosulfan is sensitive to moisture, bases,
and acids and decomposes slowly by hydrolysis to S02 and
endosulfan alcohol.
In the environment, endosulfan is metabolically coverted
by microorganisms, plants, and animals to endosulfan sulfate,
endosulfandiol, endosulfan ether, endosulfan hydroxyether,
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and endosulfan lactone (Martens, 1976; Chopra and Mahfouz,
1977; Gorbach, et al. 1968). Of these conversion products,
endosulfan sulfate is of toxicologic importance.
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REFERENCES
Berg, H. 1976. Farm chemicals handbook. Meister Publishing
Co., Willoughby, Ohio.
Braun, H.E., and R. Frank. 1973. Unpublished data. In Endo-
sulfan: Its effects on environmental quality. Natl. Res.
Counc. Can., Ottawa.
Brooks, G.T. 1974. Chlorinated insecticides. CRC Press,
Cleveland, Ohio.
Burchfield, H.P., and D.E. Johnson. 1965. Guide to the anal-
ysis of pesticide residues. U.S. Government Printing Office,
Washington, D.C.
Cassil, C.C., and P.E. Drummond. 1965. A plant surface oxi-
dation product of endosulfan. Jour. Econ. Entomol. 58: 356.
Chopra, N., and A. Mahfouz. 1977. Metabolism of endosulfan
I, endosulfan II, and endosulfan sulfate in tobacco leaf.
Jour. Agric. Food Chem. 25: 32.
Gorbach, S.G., et al. 1968. Metabolism of endosulfan in milk
sheep. Jour. Agric. Food Chem. 16: 95.
Martens, R. 1976. Degradation of (8,9,-C-14) endosulfan by
soil microorganisms. Appl. Environ. Microbiol. 31: 853.
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Whetstone, R.R. 1972. Kirk-Othmer encyclopedia of chemical
technology. John Wiley and Sons, Inc., New York.
Windholz, M. ed. 1976. The Merck Index. Merck and Co., Inc.
Rahway, N.J.
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AQUATIC LIFE TOXICOLOGY*
FRESHWATER ORGANISMS
Introduction
Endosulfan is a broad spectrum chlorinated cyclodiene in-
secticide. Although restrictions on the use of endosulfan in
the United States have been proposed, significant commercial use
continues for insect control on vegetables, fruits, alfalfa, and
tobacco. Most of the acute studies were carried out under
static conditions and with unmeasured concentrations. For most
of these studies technical-grade endosulfan or formulations con-
taining technical endosulfan were used. Technical-grade endo-
sulfan is a 94- to 96-percent mixture of stereo isomers, endo-
sulfan I and II, in a ratio of 70:30. Toxicity of the isomers
may be different, but insufficient data are available to deter-
mine which isomer is more toxic and the relative toxicity
*The reader is referred to the Guidelines for Deriving Water
Quality Criteria for the Protection of Aquatic Life [43 FR 21506
(May 18, 1978) and 43 FR 29028 (July 5, 1978)] in order to better
understand the following discussion and recommendation. The
following tables contain the appropriate data that were found in
the literature, and at the bottom of each table are the calcula-
tions for deriving various measures of toxicity as described in
the Guidelines.
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of the two isomers may vary with' the species tested. Data re-
ported herein, except for the Final Plant Value, were based on
tests using technical-grade endosulfan. Tests using formulations
such as emulsifiable concentrates were not used because of pos-
sible effects of other components of the formulation.
Two studies were conducted on the effect of temperature on
endosulfan toxicity, and one study was conducted on the effect of
water hardness (Macek, et al. 1969; Schoettger, 1970a; Pickering
and Henderson, 1966). In general, based on the limited data,
toxicity increased with increasing temperature but hardness had no
effect.
One invertebrate and one fish chronic test have been con-
ducted (Macek, et al. 1976). No measured steady-state freshwater
bioconcentration test data are available, and only one value for a
plant effect is available.
Acute Toxicity
Static tests were conducted in all but one study (Macek, et
al. 1976) (Table 6). In only one of the static tests was the con-
centration of endosulfan measured (Herzel and Ludemann, 1971)
(Table 6). Values for the standard tests with fish and inver-
tebrate species are given in Tables 1 and 2.
In general, fish were more sensitive to endosulfan than in-
vertebrate species. Adjusted LC50 values for fish ranged from 0.2
y.g/1 for rainbow trout, to 4.9 ug/1 for carp (Table 1). Adjusted
LC50 values for invertebrate species ranged from 1.9 ug/1 for the
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stonefly, Pternoarcys californica, to 140.6 ug/1 for the clado-
ceran, Daphnia magna (Table 2).
Several of the authors, cited in Tables 1 and 2, reported
values for other pesticides in addition to endosulfan. For fish,
endosulfan was second in toxicity only to endrin in acute studies
with both organophosphate and organchlorine insecticides (Macek,
et al. 1969; Ludemann and Neumann, 1960). For invertebrate
species, endosulfan had medium toxicity among the chlorinated
hydrocarbon insecticides. Sanders (1972 and 1969) found endosul-
fan to be less toxic than DDT and endrin, but more toxic than
lindane, toxaphene, chlordane, heptachlor, and dieldrin for two
species of scud, Gammarus fasciatus and Gammarus lacustris.
Sanders and Cope (1968) found somewhat different results for the
stonefly. Endosulfan was less toxic than endrin, dieldrin, and
heptachlor, but more toxic than lindane, DDT, and chlordane.
Toxaphene had toxicity similar to endosulfan. Ludemann and
Neumann (1962) found endosulfan less toxic than DDT and chlordane,
but more toxic than heptachlor for the midge, Chironomus plumosus.
Lindane was similar in toxicity to endosulfan.
For fish, endosulfan was consistently one of the most toxic
pesticides tested. For invertebrate species, it is difficult to
determine how much of the variation in the results of toxicity
tests with the different pesticides is due to species sensitivity
or test variation.
Pickering and Henderson (1966) studied the effect of water
hardness on toxicity of endosulfan and observed no significant
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effect. Unadjusted 96-hour LC50- values for the bluegill exposed
to technical-grade endosulfan in soft and hard water were 3.3 ug/1
and 4.4 ug/1/ respectively.
In contrast to the effect of hardness, toxicity of endosulfan
generally increased with increasing temperature. Macek, et al.
(1969) found an increase in toxicity to rainbow trout when tested
at 7.2 and 12.7°C as compared to 1.6°C (Table 1). Schoettger
(1970b) found that endosulfan toxicity increased with tempera-
ture for rainbow trout tested at 10°C as compared to 1.5°C. He
also found that endosulfan toxicity increased with temperature
for white sucker, and Daphnia magna when tested at 19°C compared
to 10°C. The only exception was the damselfly, Ischura sp.,
which showed decreased toxicity when tested at 19°C as compared
to 8°C (Table 2). Although not shown in the tables, the dif-
ferences in toxicity with temperature were usually greater at 24
hours than at 96 hours.
Several authors reported LC50 values for fish after 24-, 48-,
and 96-hours exposure to endosulfan. In general, they found
toxicity increased slightly with time but considerable differences
between species existed, however.
For fish, the ratio of 96-hour/24-hour and 96-hour/48-hour
LC50 values ranged from 0.13 to 0.95 and from 0.27 to 1.00, re-
spectively. The geometric means of the ratios grouped by species
were 0.51 for the 96-hour/24-hour LC50 value and 0.66 for the
96-hour/48-hour LC50 value. These ratios are approximately 20
percent less than the Guidelines values (0.66 and 0.81 for adjust-
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ment of 24-hour and 48-hour LC50 values, respectively). Consider-
ing the variation and the limited number of data points (four),
the ratios are reasonably close to the Guidelines values. The
Guidelines value (0.81) was used for the one fish LC50 value
(Table 1) that required adjustment.
For invertebrate species, the ratio of 96-hour/24-hour LC50
values and 96-hour/48-hour LC50 values ranged from 0.09 to 0.63
and from 0.41 to 0.91, respectively. The geometric means for the
96-hour/24-hour LC50 values and for the 96-hour/48-hour LC50
values were 0.38 and 0.61, respectively. Considering the varia-
tion and limited number of data points (four), the values are rea-
sonably close to the Guidelines values of 0.26 and 0.61.
The absence of flow-through tests with measured concentra-
tions is primarily a function of the technology and state-of-the-
art of aquatic toxicology at the time when much of the testing was
done. Measurements of test concentrations and flow-through test
procedures would probably give better data on the acute toxicity
of endosulfan for aquatic organisms. Herzel and Ludemann
(1971) (Table 6) studied the effect of test conditions on the
results of static tests. They found greater than a 6-fold
decrease in the measured concentrations of endosulfan at the end
of a 96-hour static, unaerated exposure and greater than a 40-fold
decrease in an aerated test compared to the initial concentration
at the start of the test. These results indicate the potential
problem of determining the effective exposure concentration in
static tests.
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There are no data on side-by-side comparisons of static and
flow-through tests with measured concentration of endosulfan.
Macek, et al. (1976) (Table 6), however, determined 0.86 ug/1
endosulfan to be the incipient lethal level for fathead minnows.
The test was a seven-day flow-through test with measured concen-
trations. The incipient lethal level from that test for the fat-
head minnow was greater than 3 of the 5 adjusted 96-hour values
for rainbow trout (Table 1). Rainbow trout was the most sensitive
species tested. No other data were available for comparison of
static and flow-through tests and tests with measured concentra-
tions. The Guidelines values were used for all static and unmea-
sured concentration adjustments of fish tests.
Final Fish and Final Invertebrate Acute Values were derived
using values listed in Tables 1 and 2. The LC50 values from the
literature were adjusted using the Guidelines procedures to be
equivalent to 96-hour, flow-through toxicant-measured LC50 values.
The final acute values were calculated according to the Guidelines
and were 0.49 ug/1- for fish and 0.60 ug/1 for invertebrate
species. Therefore, the Final Acute Value is 0.49 ug/1.
Chronic Toxicity
The only available fish chronic study was that of Macek, et
al. (1976) with the fathead minnow (Table 3). The test lasted 40
weeks, and growth, survival, and reproduction were monitored.
Based on no adverse effects on parental fish or offspring at 0.20
ug/1 and observed poor hatchability of control eggs hatched in
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0.40 ug/1 endosulfan, the maximum acceptable endosulfan concentra-
tion for fathead minnows was between 0.20 and 0.40 ug/1.
Since there are no measured, acute 96-hour flow-through fat-
head minnow data, there is no way to determine an application fac-
tor. Acute toxicity data, however, indicate the fathead minnow
may not be the most sensitive species. The Guidelines sensitivity
factor was, therefore, used to calculate the Final Fish Chronic
Value, 0.042 ug/1.
Chronic data for Daphnia magna are available from the study
of Macek, et al. (1976). Based on effects of endosulfan on sur-
vival of Daphnia magna through the first two generations, the
maximum acceptable concentration of endosulfan was between 2.7 and
7.0 ug/l« As with acute toxicity, the invertebrate species would
appear to be less sensitive to chronic endosulfan toxicity than
fish. It should be noted, however, that Daphnia magna in the
acute tests was one of the less sensitive invertebrate species to
endosulfan toxicity. The Guidelines sensitivity factor was used
to calculate the Final Invertebrate Chronic Value which is 0.84
ug/1 (Table 4).
Plant Value
The only plant-effect data was obtained from a study by
Gorback and Schulze (1973). In that study growth of the green
alga, Chlorella vulgaris, was inhibited at concentrations greater
than 2,000 ug/1 (Table 5). Since this is the only plant value,
the Final Plant Value is 2,000 ug/1.
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Residues
No acceptable bioconcentration studies with endosulfan were
conducted with freshwater fish. Because endosulfan is a chlor-
inated cyclediene insecticide and other members of that group of
insecticides bioconcentrate, data for accumulation of endosulfana
by freshwater fish and invertebrate species would be useful for
more complete development of criteria. Data on saltwater or-
ganisms indicate endosulfan does concentrate up to 1,597 times
(see Saltwater section).
Miscellaneous
Other data for effects of endosulfan are listed in Table 6.or
None of the data in these studies indicate that the final acute
chronic values calculated for endosulfan are inappropriate.
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CRITERION FORMULATION
Freshwater-Aquatic Life
Summary of Available Data
The concentrations below have been rounded to two significant
figures.
Final Fish Acute Value = 0.49 ug/1
Final Invertebrate Acute Value = 0.60 ug/1
Final Acute Value = 0.49 ug/1
Final Fish Chronic Value = 0.042 ug/1
Final Invertebrate Chronic Value = 0.84 ug/1
Final Plant Value = 2,000 ug/1
Residue Limited Toxicant Concentration = not available
Final Chronic Value = 0.042 ug/1
0.44 x Final Acute Value = 0.22 ug/1
The maximum concentration of endosulfan is the Final Acute
Value of 0.49 ug/1 and the 24-hour average concentration is the
Final Chronic Value of 0.042 ug/1- No important adverse effects
on freshwater aquatic organisms have been reported to be caused by
concentrations lower than the 24-hour average concentration.
CRITERION: For endosulfan the criterion to protect
freshwater aquatic life as derived using the Guidelines is 0.042
ug/1 as a 24-hour average and the concentration should not exceed
0.49 ugl at any time.
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Table 1. Freshwater fish acute values for endosulfan
DO
M
o
Organism
Rainbow trout,
Salmo gairdneri
Rainbow trout,
Salmo gairdneri
Rainbow trout, \
Salmo gairdneri
Rainbow trout,
Salmo gairdneri
Rainbow trout,
Salmo gairdneri
Carp (fingerling),
Cyprinus carpio
White sucker,
Catostomus commersoni
White sucker,
Catostomus commersoni
Ouppy,
Poecilia reticulata
Bluegill,
Lepomis macrochirus
Bluegill,
Lepomis macrochirus
Bioassay Test
Method* Cone,**
* S = static
** U = unmeasured
U
Adjusted
Chemical Time LC50 LCbO
Description (hrs) (uy/i) (uq/1) heterence
Technical 96 2.6 1.4 Macek, et al.
grade 1969
Technical ' 96 1.7 0.9 Macek, et al.
grade 1969
Technical 96 1.5 0.8 Macek, et al.
grade • 1969
Technical 96 0.8 0.4 Schoettger,
grade 1970
Technical 96 03 0.2 Schoettger,
grade 1970
Technical 48 11.0 4.9 Ludemann &
grade Neumann, 1960
Technical 96 35 1.9 Schoettger,
grade 1970
Technical 96 3.0 1.6 Schoettger,
grade 1970
Technical 96 3.7 2.0 Pickering &
grade Henderson,
1966
Technical 96 3.3 1.8 Pickering &
grade Henderson,
1966
Technical 96 4.4 2.4 Pickering &
grade Henderson,
1966
1.9
Geometric mean of adjusted values = 1.9 pg/1 - = 0.49 yg/1
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Table 2. Freshwater invertebrate acute values for endosulfan
03
1
M
Organism
Cladoceran,
Daphnia magna
Cladoceran,
Daphnia magna
Cladoceran,
Daphnia magna
Scud,
Gamrnarus fasciatus
;
Scud,
Gammarus lacustris
Stonef ly (naiad) ,
Pteronarcys californica
Damself ly (naiad) ,
Ischura sp.
Damself ly (naiad),
Ischura sp.
Bioassay
Method*
S
S
S
S
S
S
S
S
Test
Cone ***
U
U
U
U
U
U
U
U
Chemical
Description
Technical
grade
Technical
grade
Technical
grade
Technical
grade
Technical
grade
Technical
grade
Technical
grade
Technical
grade
Time
(nrs)
48
48
48
96
96
96
96
96
LCbO
(uq/i)
166.0
132.0
62.0
6.0
5.8
2.3
71.8
107.0
Adjusted
LCio
(uq/1)
140.6
111.8
52.5
5.1
4.9
1.9
60.8
90.6
Reference
Macek, et al
1976
Schoettger,
1970
Schoettger,
1970
Sanders, 1972
Sanders, 1969
_
Sanders &
Cope, 1968
Schoettger,
1970
Schoettger,
1970
* S = static
** -U = unmeasured
Geometric mean of adjusted values • 12.7 pg/1
+ = 0.60 pg/1
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I
M
ro
Tattle 3. Freshwater fish chronic values for endosulfan (Macek, et al. 1976)
Chronic
Limits Value
Organism Test* (ug/i) (ug/1)
Fathead minnow, LC 0.20-0 40 0.28
Pimephales promelas
* LC = life cycle or partial life cycle
Geometric mean of chronic values
Lowest chronic value = 0.28 pg/1
0 28
Geometric mean of chronic values = 0.28 pg/1 >' -, - 0.042 ng/1
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I
M
U)
Table 4. Freshwater invertebrate chronic values for endosulfan (Macek, et al. 1976)
Chronic
Limits Value
Organism Test* (uq/H (uq/H
Cladoceran, LC 2.7-7.0 4.3
Daphnia magna
* LC = life cycle or partial life cycle
Geometric mean of chronic value
Lowest chronic value =4.3 pg/1
Geometric mean of chronic values - 4.3 ug/1 F^-- - 0.84 wg/1
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fable 5 Freshwater plant effects for endosulfan (Knauf & Schulze, 1973)
Concentration
Organism Effect (uq/i)
Green alga. Inhibited > 2,000
Chlorella vulgaris growth in Endosulfan
120-hrs 35 EC
test
Lowest plant value ™ 2,000 vig/1
CD
I
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Table 6 • Other freshwater data for endosulfan
CXI
M
ui
Organism
Midge (larva),
Chironomus plumosus
Rainbow trout (fry),
Salmo gairdneri
Northern pike
(fingerling).
Esox lucius
Fathead minnow,
Pimephales promelas
Carp,
Cyprinus carpio
Carp.
Cyprinus carpio
Mosquitofish,
Gambusia affinis
Mosquitofish,
Gambusia affinis
Guppy,
Poecilia reticulata
Gupoy,
Poecilia reticulata
Test
Duration Ettect
24 hrs LC50
24 hrs 100% mortality
24 hrs 100% mortality
7 days Incipient LC50
24 hrs 70% mortality, 2%
emulsifiable
concentrate
24 hrs 607. mortality in cages
submerged in ponds dosed
with Endosulfan 2%
emulsifiable
concentrate
24 hrs 6% mortality in cages
submerged in ponds—
dosed with ThiodarfB)
I, 2% emulsifiable
concentrate
24 hrs 247. mortality in cages
submerged in ponds,.--,
dosed with Thiodarf^
II, 27. emulsif iable
concentrate
5 hrs 1007. mortality
96 hrs 857. mortality in
unaerated static
test, technical grade
Result
(uq/i) getererice
53
Ludemann & Neumann, 1962
10 Ludemann & Neumann, 1961
5 Ludemann & Neumann, 1961
0.86 Macek, et al. 1976
10 Mulla, et al. 1967
25 Mulla, et al. 1967
0.1 Mulla, 1963
Ibs/acre
0.1 Mulla, 1963
Ibs/acre
50
Jones, 1975
4.2 Herzel & Ludemann, 1971
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Table 6. (Continued)
03
Organism
Guppy.
Poecilia reticulata
Blueglll,
Lepomis macrochirus
Bullfrog (tadpole),
Rana catesbeiana
Bullfrog (tadpole),
Rana catesbeiana
Tubificid worm,
Tubifex tubifex
Mallard (young),
Anas platyrhynchus
Test Result
Duration Effect
96 hrs 55% mortality in 4.2
aerated static
test, technical grade
Unspecified 507. inhibition of 6,050
brain mitochondrial
Mg - ATPase
Reference
Herzel & Ludemann, 1971
Yap, et al. 1975
24 hrs 60% mortality in
cages submerged in /„•,
ponds dosed with Thiodart^'
I, 27. emulsifiable
concentrate
96 hrs 107, mortality in
cages submerged in -5-,
ponds dosed with Thiodan^
II, 2% emulsifiable
concentrate
0 1 Mulla, 1963
Ibs/acre
0.1 Mulla, 1963
Ibs/acre
96 hrs 100% mortality
5 days 50% mortality
10,000
Ludemann & Neumann, 1962
1,050 mg/kg Hill, et al. 1975
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SALTWATER .ORGANISMS
Introduction
The organochlorine insecticide, endosulfan, has been used for
many years to control pests that infest a wide spectrum of fruits
and vegetables. Technical endosulfan is composed of two stereo-
isomers, endosulfan I and II, in the approximate ratio of 70:30.
Both isomers are readily metabolized to endosulfan sulfate by a
wide variety of organisms (Maier-Bode, 1968).
The acute toxicity of endosulfan to saltwater fishes and
crustaceans was documented as early as 1963 (Butler, 1963). No
chronic studies have been conducted on saltwater animals; however,
several bioconcentration studies were conducted in the mid-1970"s
(Roberts, 1972, 1975; Schimmel, et al. 1977).
Acute Toxicity
Saltwater fishes exposed to endosulfan exhibited toxic ef-
fects at concentrations below 1 u-9/1 (Table 7). Of the five
species tested, the unadjusted 48- or 96-hour LC50 values ranged
from 0.09 to 0.6 ug/1 (Butler, 1963, 1964; Korn and Earnest, 1974;
Schimmel, et al. 1977). With the exception of rainbow trout
(Salmo gairdneri), freshwater fishes were not as sensitive in
acute tests (Table 1).
The seven saltwater invertebrate species tested were highly
disparate in sensitivity to endosulfan (Table 8). The range of
unadjusted EC50 and LC50 values was from 0.04 to 380 ug/1. The
least sensitive invertebrate species was the eastern oyster
(Crassostrea virginica). Two EC50 values (effect measured was
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shell deposition) for this mollusc were 65 ug/1 (Butler, 1963) and
380 ug/1 (Butler/ 1964). Since both tests were conducted at
nearly identical salinities (22 °/oo and 21 °/oo, respec-
tively), the increased toxicity shown in the 1963 study may have
been the result of the higher test temperature 28°C vs. 19°C in
the Butler, 1964 study. Temperature-related toxicity of endosul-
fan was also reported in rainbow trout by Macek, et al. (1969).
The most sensitive species tested was the pink shrimp with a
96-hour LC50 of 0.04 ug/1 (Schimmel, et al. 1977).
The acute toxicity of endosulfan to saltwater organisms may
be underestimated when LC50 values are based on nominal concen-
trations, thereby justifying the need to adjust these values for
test conditions. For example, Schimmel, et al. (1977) exposed two
species of shrimp (Penaeus duorarum and Palaemonetes pugio) and
three species of saltwater fishes (Mugil cephalus, Lagodon
rhomboides and Leiostomus xanthurus) to endosulfan and reported
that all LC50 values based on measured concentrations were lower
than those based on nominal concentrations. Variability in
species sensitivity of fishes exposed to endosulfan was very small
(0.09 to 0.6 ug/1; Table 7) compared with that of invertebrate
species tested (0.04 to 380 ug/1). Therefore, use of the greater
species sensitivity factor for invertebrate species appears justi-
fied. The use of the species sensitivity factor (3.7) applied to
fish acute toxicity data seems reasonable and produces a Final
Fish Acute Value of 0.061 ug/1. This value is lower than the
B-18
-------
adjusted LC50 values for all five species tested. Therefore, the
sensitivity adjustment factor appears adequate.
For invertebrate species, the use of the species sensitivity
factor (49) applied to the geometric mean of invertebrate LC50
values produces a value of 0.044 ug/1 (Table 8). Thus, the LC50
values for all but the pink shrimp (six of seven species) are
greater than this value (0.044 ug/1; Table 8). According to pro-
cedures in the Guidelines, if the LC50 value in a flow-through
test (based on measured concentrations) is lower than the geo-
metric mean LC50 value divided by the species sensitivity factor,
that LC50 (0.040 ug/1) becomes the Final Invertebrate Acute Value.
Obviously, the LC50 for pink shrimp taken as the Final Acute Value
is not protective for this species. In fact, Schimmel, et al.
(1977) reported that 20 percent of the animals died when exposed
to a nominal concentration of 0.01 ug/1 endosulfan.
Chronic Toxicity
No data were found in the literature that reported the toxi-
city of endosulfan to a saltwater fish or invertebrate species
over their entire life cycle.
Plant Effects
The only saltwater plant datum available is that of Butler
(1963) who reported an 86.6 percent decrease in productivity of
natural phytoplankton communities (as measured by 14*- uptake
during a 4-hour exposure) when- exposed to 1,000 ug/1 (Table 9).
This level is more than 10,000 times higher than those that pro-
B-19
-------
duce deleterious effects on fish or invertebrate species in acute
studies.
Bioconcentration
Several studies were conducted to determine the bioconcen-
tration of endosulfan by saltwater organisms (Table 10). Roberts
(1972 and 1975) investigated the rates of uptake, depuration, and
translocation and the bioconcentration factor (BCF) of endosulfan,
using the estuarine bivalve Mytilus edulis. In both studies, he
reported very low BCF values (12 after 112 days to 29 after 14
days); however, no mention was made of the analysis for endosulfan
sulfate, the metabolite of technical endosulfan. Analyses for the
metabolite are important because Knauf and Schulze (1973) have
shown that metabolites of endosulfan that contain the sulphur atom
exhibit toxicities to aquatic vertebrates and invertebrates that
are similar to those of the technical material. Schimmel, et al.
(1977) studied the uptake, depuration and metabolism of endosulfan
by the striped mullet. When concentrations of endosulfans I and
II and endosulfan sulfate were combined to determine the BCF,
Schimmel, et al. (1977) reported an average whole-body BCF of
1,597; nearly all of the endosulfan measured was in the form of
the sulfate. Although the uptake portion of the study was con-
ducted for 28 days, the authors question whether a steady- state
condition was reached. After two days in an endosulfan- free
environment, no endosulfan or sulfate was detectable in the ex-
posed mullet.
B-20
-------
Since no maximum permissible tissue concentration is avail-
able for endosulfan, no Residue Limited Toxicant Concentration can
be generated.
Miscellaneous
No other data from Table 11 suggest any more sensitive
effects.
B-21
-------
CRITERION FORMULATION
Saltwater-Aquatic Life
Summary of Available 'Data
The concentrations below have been rounded to two significant
figures.
Final Fish Acute Value = 0.061 ug/1
Final Invertebrate Acute Value = 0.040 ug/1
Final Acute Value = 0.040 ug/1
Final Fish Chronic Value = not available
Final Invertebrate Chronic Value = not available
Final Plant Value = 1,000 ug/1
Residue Limited Toxicant Concentration = not available
Final Chronic Value = 1,000 ug/1
0.44 x Final Acute Value = 0.018 ug/1
No saltwater criterion can be derived for endosulfan using
the Guidelines because no Final Chronic Value for either fish or
invertebrate species or a good substitute for either value is
available, and there are insufficient data to estimate a criterion
using other procedures.
B-22
-------
Table 7. Marine fish acute values for endosulfan
0)
1
to
Ul
Bioassay Test
Organism Method* Cone .**
Striped bass, FT U
Morone saxatilis
Pinfish. FT M
Lagodon rhomboides
Spot. FT M
Leiostomus xanthurus
Spot, FT U
Leiostomus xanthurus
Striped mullet. FT M
MuRJl cephalus
White mullet. FT U
Mugil cureraa
»•
Adjusted
Time LC50 LC50
(hre) (uq/H (uq/1) Reference
96 0.1 0 077 Korn & Earnest. 1974
96 0.3 0.3 Schimmel. et al. 1977
96 0.09 0.09 Schimmel, et al. 1977
48 0.6 0.37 Butler, 1964
96 0.38 0.38 Schimmel, et al. 1977
48 0.6 0.37 Butler, 1963
* FT = flow-through
**M ° measured, U •» unmeasured
0 226
Geometric mean of adjusted values = 0.226 yg/1 * H-- - 0.061 iig/1
Lowest value from a flow-through test with measured concentrations «• 0.09 yg/1
-------
Table 8 • Marine invertebrate acute values for endosulfan
Bioassay Test
Adjusted
Time < I£50 LCbO
(fits)
03
1
N>
,fw
i • i :
Eastern oyster,
Crassostrea virginica
Eastern oyster.
Crassostrea virginica
Blue crab,
Callinectes sapidus
brown shrimp.
Crangon crangon
Korean shrimp,
Palaemon macrodactylus
Korean shrimp,
Palaemon macrodactylus
Grass shrimp,
Palaemonetes pugio
brown shrimp,
Penaeus aztecus
Pink shrimp,
Penaeus duorarum
FT
FT
FT
S
S
FT
FT
FT
FT
.
U
U
U
U
U
U
M
U
M
-
96
96
48
• 48
96
96
96
48
96
~ . * -
65
380.
35
10.
17.
3.
1.
0.
0
p.-fc.
***
***
***
0
1
4
31
4***
04
50.
293
11.
3.
14.
2.
1.
0
0
***
***
6***
64
5
6
31
13***
04
Butler. 1963
Butler. 1964
Butler. 1963
Portman & Wilson,
Schoettger, 1970
Schoettger. 1970
Schimmel, et al.
Butler. 1963
Schimmel, et al.
1971
1977
1977
* S = static, FT = flow- through
** M = measured, U = unmeasured
***EC50 Abnormal development of oyster larvae, decreased growth of oysters, or loss of equilibrium
of shrimp or blue crabs.
Geometric mean of adjusted values = 2 15 yg/1
= 0.044 pg/1
Lowest value from a flow- through test with measured concentrations =0.04 pg/1
-------
Table 9.Marine plant effects for endosulfan (Butler, 1963)
Concentration
Organism Effect (uq/1)
Natural phytoplankton 86.67. decrease 1,000
communities in productivity,
1,000 l"C in a 4-
hour exposure.
Lowest plant value = 1,000 yg/1
00
I
to
Ul
-------
00
I
N;
Tatle 10 Marine residues for endosulfan
Time
Organism Bioconcentration Factor (days) xeterence
Common mussel,
Mytilus edulis
Common mussel,
Mytilus edulis
Striped mullet,
Mugil cephalus
12
29
i
1,597*
112
14
28
Roberts, 1972
Roberts, 1975
Schimmel, et al 1977
*Bioconcentration factor includes bioconcentration of the metabolite, endosulfan sulfate
-------
Table 11. Other marine data for endosulfan (Schimmel, et al. 1977)
Cfl
1
10
Organism
Grass shrimp,
Palaemonetes pugio
Pinfish,
Lagodon rhomboides
Spot,
Leiostomus xanthurus
Striped mullet,
Mugil cephalus
*Bioconcentration factor
Test
Duration
A days
A days
A days
A days
includes
Result
Ettect
-------
ENDOSULFAN
REFERENCES
Butler, P.A. 1963. Commercial fisheries investigations/
pesticide-wildlife studies, A review of Fish and Wildlife
Service Investigations during 1961 and 1962. U.S. Oep.
Inter. Fish Wildl. Circ. 167: 11.
Butler, P.A. 1964. Pesticide-wildlife studies. 1963.
A review of Fish and Wildlife Service Investigations during
the calendar year. U.S. Dep. Inter. Fish Wildl. Circ. 199: 5.
Herzel, F., and D. Ludemann. 1971. Verhalten and Toxizitat
von Endosulfan in Wasser unter verschiedenen Versuchsbed-
ingungen. Z. Angew. Zool. 58: 57.
Hill, E.F., et al. 1975. Lethal dietary toxicities of
environmental pollutants to birds. U.S. Fish_Wildlife.
Serv. Spec. Sci. Rep. Wildl. 191.
Jones, W.E. 1975. Detection of pollutants by fish tests.
Water Treat. Examin. 24: 132.
Knauf, W., and E.F. Schulze. 1973. New findings on the
toxicity of endosulfan and its metabolites to aquatic organisms,
Meded. Fac. Lanbouwwet, Rijksuniv. Gent. 38:"717. '
B-28
-------
'Korn, S., and R. Earnest. 1974. Acute toxicity of 20
insecticides to striped bass Morone saxatilis. Calif. Fish
Game 60: 128.
Ludemann, D., and H. Neumann. 1960. Versuche uber die
akute toxische Wirkung neuzeitlicher Kontaktinsektizide
auf einsommerige Karfen (Cyprinum carpio L.) Z. Angew.
Zool. 47: 11.
Liidemann, D., and H. Neumann. 1961. Versuche uber die
akute toxische Wirkung neuzeitlicher Kontaktinsektizide
auf Susswassertiere. Z. Angew. Zool. 48: 87.
Liidemann, D., and H. Neumann. 1962. Uber die Wirkung der
neuzeitlichen Kontaktinsektizide auf die Tiere des Slisswassers,
Anz. Shadlingsunde*. 35: 5.
Macek, K.J., et al. 1969. The effects of temperature on
the susceptibility of bluegills and rainbow trout to selected
pesticides. Bull. Environ. Contam. Toxicol. 4: 174.
Macek, K.J., et al. 1976. Toxicity of four pesticides
to water fleas and fathead minnows. EPA 600/3-76-099. U.S.
Environ. Prot. Agency.
Maier-Bode, H. 1968. Properties, effect, residue and
analytics of the insecticide endosulfan. Res. Rev. 22: 1.
B-29
-------
Mulla, M.S. 1963. Toxicity of organochlorine insecticides
to the mosquito fish Gambusia affinis and the bullfrog Rana
catesbeiana. Mosq. News 23: 299.
Mulla, M.S., et al. 1967. Evaluation of organic pesticides
for possible use as fish toxicants. Prog. Fish-Cult. 29: 36.
Pickering, Q.H., and C. Henderson. 1966. The acute toxicity
of some pesticides to fish. Ohio Jour. Sci. 66: 508.
Portman, J.E., and K.W. Wilson. 1971. The toxicity of
140 substances to the brown shrimp and other marine animals.
Ministry Agri. Fish. Food. Shellfish Info. Leaflet No.
22.
/
Roberts, D. 1972. The assimilation and chronic effects
of sub-lethal concentratioans of endosulfan on condition
and spawning in the common mussel Mytilus edulis. Mar.
Biol. 16: 119.
Roberts, D. 1975. Differential uptake of endosulfan by
the tissues of Mytilus edulis. Bull. Environ. Contam.
Toixicol. 13: 170.
Sanders, fl.O. 1969. Toxicity of pesticides to the crustacean
Gammarus lacustris. U.S. Bur. Sport Fish. Wildl. Tech. Pap. 25,
B-30
-------
Sanders, H.O., and O.B. Cope. 1968. The relative toxicities
of several pesticides to naiads of three species of stone-
flies. Limnol. Oceanogr. 13: 112.
Schimmel, S.C., et al. 1977. Acute toxicity to and biocon-
centration of endosulfan by estuarine animals. Aquatic
toxicology and hazard evaluation. ASTM STP 634, Am. Soc.
Test. Mater.
Schoettger, R.A. 1970a. Toxicology of thiodan in several
fish and aquatic invertebrates. Investigations in fish
control. U.S. Bur. Sport Fish. Wildl. 35.
Schoettger, R.A. 1970b. Fish-pesticide research laboratory,
progress in sport fishery research. U.S. Dep. Inter. Bur.
Sport Fish Wildl. Resour. Publ. 106.
Yap, H.H., et al. 1975. Ln vitro inhibition of fish brain
ATPase activity by cyclodiene insecticides and related com-
pounds. Bull. Environ. Contain. Toxicol. 14: 163.
B-31
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Mammalian Toxicology and Human Health Effects
EXPOSURE
Ingestion from Water
Schulze, et al. (1973) presented data from the U.S. Ge-
ological Survey program for monitoring pesticides in the
streams of the western United States for the period October
1968 to September 1971. At 20 sampling stations, water sam-
ples were collected at monthly intervals and analyzed for
residues of endosulfan and other pesticides by gas chromato-
graphy. No attempt was made to separate suspended sediment
from the water for separate analysis. The low detection
limit for endosulfan was ^-»0.005 ug/1. In a total of 546
water samples analyzed, one sample (from the Gila River at
Gillespie Dam, Arizona) contained an endosulfan residue of
0.02 ug/1, along with residues of five other organochlorine
insecticides.
FMC (1971) reported endosulfan levels in runoff water in
North American agricultural areas. Water samples from a pond
located in a field treated with endosulfan contained no de-
tectable residues (<10 ug/1). Mud samples from the bottom of
the pond, however, contained a maximum of 0.05 mg/kg ^-endo-
sulfan and 0.07 mg/kg endosulfan sulfate. These samples were
taken approximately 280 days after the last endosulfan appli-
cation.
In a subsequent study, irrigation runoff was monitored
from a field in California treated at a rate of 1.12 kg/ha
(FMC, 1972). Water residues (o<- and ^-endosulfan) were
C-l
-------
approximately 15 ug/1 following the first irrigation but
dissipated to below the detection limit (.005 ug/D after 15
days.
Miles and Harris (1971) measured insecticide residues in
the water of a creek flowing into Lake Erie and in ditches
draining an agricultural area near Lake Erie. In these water
systems, water was sampled weekly and bottom mud was sampled
monthly from mid-April to mid-October 1970. No endosulfan
residue.s were found in the creek. In the drainage ditch, en-
dosulfan residues in the water ranged from <2 to 32 ng/1 at
the pumphouse where the water was lifted into Lake Erie when
necessitated by the water level and from <2 to 187 ng/1 one
mile upstream from the pumphouse. Endosulfan residues in
bottom mud were <1 to 1 ug/1 (dry weight basis) at the pump-
house, and ranged from 4 to 62 U9/1 upstream.
In 1971, in order to compare residue contributions from
areas of differing insecticide use, Miles and Harris (1973)
determined insecticide .residues in water systems draining ag-
ricultural, urban-agricultural, and resort areas in Ontario,
Canada. Water, bottom mud, and fish samples from these water
systems were collected between mid-April and mid- October and
analyzed for endosulfan residues by gas-liquid chromatogra-
phy. Endosulfan residues in individual water samples ranged
from <1 to 11 ng/1 in Big Creek and from <1 to 3 ng/1 in the
Thames River (average level for all samples was <1 ng/1);
none were found in the Muskoka River (limit of detection 1
ng/1). No endosulfan residues were detected in 18 samples
C-2
-------
of bottom mud or in a total of 57 fish collected from the
three water systems.
The National Research Council of Canada (NRCC) (1975)
reports unpublished data (Frank, 1973) on endosulfan residues
in water samples collected four times per year between 1968
and 1973 in six southern Ontario rivers and municipal water
supplies. Over this period, endosulfan was detected only in
one sample, at a level of 0.012 u9/l- In 1973, five water
and three sediment sampling sites were monitored at two-week
intervals from late March to mid-September, and monthly
thereafter. Endosulfan residues were detected only in water
during one sampling period at levels of 0.047 to 0.083 ug/1•
Frank, et al. (1977) subsequently published the results
of pesticide analysis of 50 sediment samples collected on a
grid from Lake St. Clair in 1970 and 1974. In 1970, endosul-
fan residues were present in the sediments at a mean residue
of 0.2 ug/kg (ranging from nondetectable levels «0.2 ug/kg)
to 2.2 ug/kg). Only 20 percent of the samples, however, con-
tained endosulfan and these residues (eA- and ^-endosulfan
with traces of endosulfan sulfate) were confined to sediments
from the lower reaches of the ship channel between Lake St.
Clair and the Detroit River and offshore from the mouth of
the Thames River. Endosulfan was not detected in any of the
1974 samples.
Endosulfan residues in Lakes Erie and Ontario have been
reported by the Environmental Quality Coordination Unit
(1973) of the Canada Centre for Inland Waters. Of 40 samples
C-3
-------
of surface and bottom waters from Lake Erie, five contained
/
endosulfan concentrations ranging from 0.005 to 0.014 ug/1.
Of 40 Lake Ontario samples, six contained endosulfan at con-
centrations of 0.005 to 0.051 ug/1. Residues in the sediment
samples and in the other water samples were below the de-
tection limits, 0.005 ug/1 of water and 5 to 10 ug/kg of
sediment.
Wong and Donnelly (1968) measured pesticide concentra-
tions in the St. Lawrence River and in the Bay of Quinte
which empties into the northern shore of Lake Ontario. Endo-
sulfan was generally nondetectable in the St. Lawrence River,
but a few samples contained endosulfan residues between 0.020
and 0.060 ug/1.
Several laboratories studied the occurrence of endosul-
fan residues in the Rhine River in West Germany and in the
Netherlands following a massive endosulfan-caused fish kill
in the Rhine in June 1969 due to an accidental point source
contamination. This episode was the result of accidental
discharge of approximately 220 Ib of endosulfan into the
river system rather than from runoff (NRCC, 1975, New York
Times, 1969.
Seivers, et al. (1972) monitored the concentrations of
endosulfan in the Rhine and Main Rivers in West Germany from
June to December 1969. During this period, 55 and 22 water
samples were obtained from different locations along the
Rhine and Main, respectively. The endosulfan concentrations
found in these samples were within the following ranges:
C-4
-------
Endosulfan concentration
range (ng/1)
<100
100-500
500-1,000
1,000-10,000
>10,000
Total
Number of samples from
Rhine Main
21 (38%)
27 (49%)
4 (7%)
3 (6%)
0 (0%)
55 (100%)
3 (14%)
1 (4%)
4 (18%)
9 (41%)
5 (23%)
22 (100%)
Many communities along the Rhine draw their water sup-
plies from the river. Endosulfan residues in 35 samples of
Rhine shore filtrates collected between June, 1969 and Febru-
ary 1970 contained endosulfan concentrations ranging from <10
to 35 ng/1.
Greve and Wit (1971) determined endosulfan concentra-
tions in about 320 samples of surface water and 35 samples of
drinking water collected between June 24 and August 31, 1969,
from the Dutch section of the Rhine and its tributaries fol-
lowing a massive fish kill the previous June. Endosulfan was
identified by gas-liquid chromatography. The maximum concen-
tration of endosulfan (e^ + <£) found in river water in the
Netherlands was 0.70 u.g/1 on the first day of sampling. From
this maximum value, a steady decrease was observed; one month
after initiation of sampling, the endosulfan concentration
had fallen below the limit of detectability, 0.01 ug/1.
In tests concerning drinking water preparation, Greve
and Wit (1971) found that river silt readily adsorbs endo-
sulfan. Of the endosulfan present in raw river water sam-
ples, 82 to 85 percent could be removed by filtration or
C-5
-------
centrifugation. Ferric hydroxide gel and activated carbon
were still better adsorbents for endosulfan. Ferric hydrox-
ide gel not only adsorbed endosulfan, but also catalyzed its
hydrolysis.
In a more extended monitoring study, Greve (1972) mea-
sured endosulfan residues in the Dutch section of the Rhine
River from September 1969 to March 1972. During this period,
water samples were collected three times a week in the Waal
River, the main branch of the Rhine River in the Netherlands.
Endosulfan (d+^) residues were found in 75 percent of the sam-
ples, ranging from <0.01 to 0.88 ug/1; the average and median
endosulfan concentrations were 0.10 and <0.01 ug/1, respec-
tively, and the upper and lower deciles were <0.01 to 0.29
ug/i.
Wegman and Greve (1978) monitored the Dutch aquatic
environment from September 1969 to December 1975 for organo-
chlorine pesticides. Some 1,492 samples were analyzed, in-
cluding surface water, rainwater, groundwater, and drinking
water. The results of these analyses were as follows:
No. of sample sets analyzed
Endosulfan^/TotalMaximum endosulfan3/
Year containing No. residue (ug/1)
1969 IT 32 0.81
1970 36 45 0.40
1971 9 22 0.25
1972 7 35 0.09
1973 9 22 0.10
1974 1 3 0.02
1975 1 1 0.02
a/ tf\- and /^-endosulfan; practical detection limit is 0.01
ug/i.
C-6
-------
Herzel (1972) monitored organochlorine insecticides in
surface waters in the Federal Republic of Germany. Samples
of unfiltered water and suspended solids were analyzed from
about 25 sites sampled in May 1971, and unfiltered water was
analyzed from seven sites sampled monthly between April 1970
and June 1971. All samples were analyzed by gas chromato-
graphy, and the detection limits for &- and ^-endosulfan were
10 to 30 ng in 30 ml of hexane extract. Of 120 samples of
unfiltered surface waters analyzed, eight contained residues
of^-endosulfan ranging from 10 to 100 ng/liter, and three
contained residues of ^-endosulfan ranging from 20 to 95 ng/1.
These endosulfan concentrations were found in samples from
the Rhine, the lower Main, and the Regnitz and, according to
the investigator, originated from industrial effluents.
Of 20 samples of suspended solids, two contained ^-endo-
sulfan an at concentrations of 22 and 24 ng, and one con-
tained ^-endosulfan at a concentration of 9.6 ng. These
values are expressed in terms of the quantities of each endo-
sulfan isomer (in nanograms) found in the solids suspended in
one liter of water.
Tarrant and Tatton (1968) studied the presence of or-
ganochlorine pesticides in rainwater in the British Isles.
The total precipitation collected in each three-month period
at seven sampling stations was analyzed by thin-layer and
gas-liquid chromatography. The detection limit for endosul-
fan was about 1 ng/1. No endosulfan residues were detected
in any of the 28 composite samples of rainwaters analyzed.
C-7
-------
Gorbach, et al. (1971a) investigated the presence and
persistence of endosulfan residues in East Java in a river
system (Brantas River) and in ponds and seawater following
large-scale use of endosulfan on rice in the delta region of
the Brantas River. The concentration of endosulfan residues
in the water sampled as determined by gas chromatography were
as follows:
Endosulfan residues (ug/D
Canals
Fish Ponds
River system
Madura Sea
Average
Range
Average
Range
Average
Range
Average
Range
<*
<0.13
<0.01-5.8
<0.03
<0. 01-0. 25
<0.01
<0. 01-5.0
<0.02
<0. 01-0. 09
^
<0.12
<0.01-2.4
<0.02
<0. 01-0. 08
<0.11
<0. 01-2.0
<0.02
<0. 01-0. 07
Sulfate
<0.18
<0. 01-0. 55
<0.06
<0. 01-0. 44
<0.19
<0. 01-0. 45
<0.08
<0. 01-0. 28
The highest residue levels (5.8 and 2.4 ug/1 of d- and
J-endosulfan, respectively) were detected in a canal that
drained treated fields shortly after an endosulfan applica-
tion. Within two days, these high levels decreased to about
0.2 ug/1 by degradation and/or dilution with uncontaminated
water. Total endosulfan residues ( a^+ 4+ sulfate) averaged
0.46 ug/1.
In connection with the same endosulfan application pro-
ject in East Java, Gorbach, et al. (1971b) also investigated
endosulfan residues in the water and mud of rice fields fol-
lowing an endosulfan treatment. Before treatment of the test
fields, total endosulfan residues (endosulfan cX+ J& + sulfate)
C-8
-------
in the water were of the order of 0.5 to 0.8 ug/1 as a result
of the large-scale endosulfan applications in the area. The
test fields were treated by knapsack sprayer at a rate equi-
valent to about 0.5 Ib Active Ingredient (AI)/acre.
After treatment, the initial water concentration of
total endosulfan residues in one field was 68 ug/1* declining
to the pretreatment value of 0.5 to 0.8 ug/1 within five
days. In the mud of both submerged test fields, maximum
total endosulfan residues were 0.053 and 0.008 mg/kg, respec-
tively, directly after treatment, declining to about 0.01 to
0.02 mg/kg by the fifth day posttreatment. In an adjacent
dry rice field, a maximum endosulfan residue of 1.9 mg/kg was
found. The sulfate equivalent in the total endosulfan resi-
dues increased with time, pointing to conversion of the
parent compound in the presence of water.
Several fish kills attributable to endosulfan have been
reported from other countries. One major, widely publicized
and investigated episode occurred in the Rhine River in West
Germany in 1969.
Osmond (1969) reported on an endosulfan-related fish
kill which took place in Ontario, Canada, in August of 1969.
Analysis of water samples collected where fish had been
killed from the Thames River and a tributary where the con-
tamination occurred showed endosulfan concentrations of 0.096
and 0.260 ug/1, respectively. Two other samples taken from
upstream on the Thames River and from further up the tribu-
tary had endosulfan levels of 0.022 and 0.026 ug/1.
09
-------
A second fish kill occurred-in a pond near Simcoe,
Ontario, in 1972 (Frank, 1972). Endosulfan could not be de-
tected in the pond water (limits of detection 0.001, 0.002,
and 0.01 ug/1 for ^-endosulfan, j#-endosulfan, and endosulfan
sulfate, respectively). However, bottom sediment from one
end of the pond contained 0.9, 1.0, and 1.1 ug/kg (dry
weight) of^-endosulfan, ^-endosulfan, and the sulfate, re-
spectively. Sediment from the other end of the pond con-
tained 1.2 ug/kg (dry weight) endosulfan sulfate.
Ingestion from Foods
Endosulfan is a broad spectrum insecticide and acaricide
that is registered in the United States for use in the con-
trol of over 100 different insect pests occurring in over 60
food and nonfood crops.
Official U.S. tolerances for pesticide residues in raw
agricultural commodities are published in the Code of Federal
Regulations, Title No. 40, and in the Federal Register.
Appropriate food additive tolerances for processed commodi-
ties are published in Title No. 21 of the Code of Federal
Regulations. U.S. tolerances for endosulfan and its metabo-
lite are listed in Table 1.
Endosulfan tolerances that have been set by other coun-
tries are summarized in Table 2.
The acceptable daily intake (ADI) is defined by Lu
(1973) as the daily intake of a pesticide which during an
entire lifetime appears to be without appreciable risk on the
basis of all known facts at the time of evaluation. It is
expressed in milligrams of the chemical per kilogram of body
weight (mg/kg).
C-10
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TABLE 1
U.S. Tolerances for Endosulfan3/
o
mg/kg
0.3
1
0.2b/
1
2
2
2
O.lb/
0.2V
2 .
O.lb/
2
2
2
0.2
0.2
2
2
2
2
0.2
1
2
Crop
Alfalfa (fresh)
Alfalfa hay
Almonds
Almond hulls
Apples
Apricots
Artichokes
Barley grain
Barley straw
Beans
Blueberries
Broccoli
Brussels sprouts
Cabbage
Carrots
Cattle (meat, fat, meat
by-products)
Cauliflower
Celery
Cherries
Collards
Corn, sweet (kernels plus
cobs with husks removed)
Cottonseed
Cucumbers
mgAg
2
0.2b/
0.2
2
0.2
0.2
2
2 .
0.2b/
2
0.5C/
2 .
0.2b/
2
0.1 b/
0.2V
2
2
2 .
0.2b/
2
2
Crop
Eggplants
Filberts
Goats (meat, fat, meat
by-products)
Grapes
Hogs (meat, fat, meat
by-products)
Horses (meat, fat, meat
by-products)
Kale
Lettuce
Macadamia nuts
Melons
Milk fat
Mustard greens
Mustard seed
Nectarines
Oats, grain
Oats, straw
Peaches
Pears
Peas (succulent type)
Pecans
Peppers
Pineapples
mg/kg
2
0.2b/
2
2 .
0.2b/
O.lJV
0 2 /
0.*2V
0.2
2
2 .
O.l^/
0.5
2
2
0,2
24V
2
2
0.2b/
2 "
O.lv
0.2^/
2
Crop
Plums
Potatoes
Prunes
Pumpkins
Rape seed
Rye grain
Rye straw
Safflower seed
Sheep (meat, fat,
meat by-products)
Spinach
Strawberries
Sugar beets with-
out tops )
Sugarcane
Summer squash
Sunflower seeds
Sweet potatoes
Tea, dried
Tomatoes
Turnip greens
Walnuts
Watercress
Wheat grain
Wheat straw
Winter squash
f;/ Includes its metabolite, endosulfan sulfate
^/ Negligible residue
£/ Negligible residue in milk
_£/ Food additive tolerance
irm
-------
TABLE 2
Tolerances Reported by Other Countries
Country
Commodity
Tolerances (mg/kg)
Australia^/
Canada"/
New Zealand^/
Netherlandsfy
South Africa^/
Fat of meat of cattle and sheep
Milk and milk products
Fruits, grain, vegetables,
cottonseed
Peas
Artichokes, beans, cauliflower,
celery, cucumber, eggplant, grapes,
melons, peppers, pumpkins, squash,
strawberries, tomatoes, watercress
Apples, apricots, broccoli,
Brussels sprouts, cabbage, cherries,
lettuce, nectarines, peaches, pears,
plums, prunes, spinach
Fruits and vegetables
Berries, mushrooms
Fruit (except berries) and
vegetables
Potatoes
Cabbage, green beans, boysenberries,
youngberries, tomatoes, cucurbits,
peas, citrus
Peaches, apples, pears
0.2
0.5 (fat basis
1.0
0.5
1.0
2.0
2.0
1.0
0.5
0.1
2.0
0.5
Source: WHO (1975)
f/ IncludescA- and /£-endosulfan and endosulfan sulfate
Includes c^,- and (^-endosulfan
Residues not specified
C-12
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The ADI for pesticides is established jointly by the
Food and Agricultural Organization (FAO) Working Party on
Pesticide Residues and the World Health Organization (WHO)
Expert Committee on Pesticide Residues, and thus is not an
officially recognized standard in the United States. The ADI
for endosulfan is 0.0075 mg/kg (FAO, 1975).
Corneliussen (1970, 1972) reported the residue levels of
several chlorinated insecticides in various foods before and
after processing by a dietician. The effect of processing on
residues of endosulfan (includes the two isomers and sulfate)
are reported for only one food class, leafy vegetables.
Corneliussen (1970) reported the residues as 0.011 mg/kg
before processing and 0.006 mg/kg after processing.
Corneliussen (1972) reported the residues as 0.007 and 0.002
mg/kg, respectively.
McCaskey and Liska (1967) studied the effect of process-
ing on the residues of endosulfan and endosulfan sulfate in
milk. One group of milk samples came from cows fed 500 to
2,000 mg/day endosulfan for 7 to 11 days; the other group of
milk samples contained endosulfan which had been added in
solution in ethyl alcohol. The investigators were not able
to detect endosulfan in the milk from the cows fed endosul-
fan, but the milk did contain endosulfan sulfate. The resi-
dues were reported on a milk fat basis since moisture was
being removed from the milk during processing. The results
are presented below.
C-13
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Residue (mg/kg, fat basis)
Endosulfan
Product sulfatea/ Endosulfanb/
Raw milk 15.2 15.9
Forewarmed milk 12.7 12.7
Condensed milk 12.6 11.4
Spray-dried milk 8.8 10.1
Evaporated milk 8.8 9.9
Drum-dried milk 4.5 8.0
a/ Detected in milk from cows administered endosulfan
Added to milk in alcohol solution
Li, et al. (1970) reported a study in which two dairy
cows were given 1 mg/kg /day endosulfan for two weeks. Anal-
yses of the dairy products (pasteurized milk, cream, butter,
cheese, dried and condensed whole milk, etc.) indicated only
a very small (not quantified) concentration of ^-endosulfan.
Endosulfan sulfate, however, was not detected.
Johnson, et al. (1975) studied the effects of freeze-
drying on the residues of endosulfan in tobacco. The treated
samples were analyzed for both endosulfan isomers and endo-
sulfan sulfate. The results are presented in Table 3.
The reduction in endosulfan residues amounted to 34 to
43 percent on a weight basis compared to the control samples.
The two types of f reeze-drying had about the same effect; the
percent reduction in residue was about the same for both high
and low initial residue levels. The percent reduction was
greater for M-endosulfan than for ^-endosulfan or endosulfan
sulfate.
C-14
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TABLE 3
The Effect of Freeze-drying on Endosulfan Residues on Tobacco
Initial
pesticide
level
Low
High
Freeze-drying
treatment
Control
Standard
Freeze-drying
Extraction +
freeze-drying
Control
Standard
Freeze-drying
Extraction +
freeze-drying
tf^-Endosulfan
0.12
0.05
0.05
0.25
0.11
0.10
Residues
^-Endosulfan
0.98
0.56
0.59
2.35
1.27
1.29
(mgAg)a/
Endosulfan
sulfate
2.43
1.59
1.68
7.65
4.45
4.94
Total
endosulfan
3.53
2.20
2.32
10.24
5.83
6.33
The analytical method was electron-capture gas chromatography
Source: Adapted from Johnson, et al. (1975)
C-15
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Beck, et al. (1966) conducted four cattle feeding tests
for the purpose of determining residues of endosulfan. In
the four tests endosulfan in the tissue, milk, alfalfa,
grass, and silage was determined by colorimetric analysis.
In one test, the investigators fed alfalfa treated with endo-
sulfan to Hereford steers and analyzed for residues of endo-
sulfan in the omental fat. Two steers were used in each ex-
periment at treatment levels of 0.15, 1.10, 2.50, and 5.00 mg
endosulfan per kilogram body weight per day. Two steers
(treatment levels 5 mg/kg/day and 2.5 mg/kg/day) developed
muscle convulsions (after 2 and 13 days, respectively); the
experiments at these levels were discontinued.
After 60 days, one of the steers receiving the 0.15
mg/kg treatment showed no residues of endosulfan in the fat
tissue, but one of the steers receiving the 1.10 mg/kg treat-
ment showed 1.0 mg/kg endosulfan in the fat tissue. Two
other steers were also fed 1.10 mg/kg of endosulfan in ace-
tone solution twice daily, and after seven days, urine and
fecal samples were taken. The two steers excreted endosulfan
at the rate of 6.7 and 5.0 mg/day in the feces and 18.5 and
15.9 mg/day in the urine. This rate of excretion accounted
for only 7.4 and 4.9 percent of the daily dose administered.
Since most of the endosulfan was not excreted or accumulated
in the body fat, the investigators concluded that it must
have been metabolized.
C-16
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Beck, et al. (1966) grazed Hereford steers on Coastal
Bermuda grass that had been treated with endosulfan. No
residues were found in the fat of any of the steers which had
been grazing from 31 to 36 days on the treated grass. The
levels of endosulfan in the grass varied from 102 mg/kg (dry
weight basis) on the first day after treatment (when one test
group began grazing) to 1.53 mg/kg on the day the last test
group had completed grazing.
Beck, et al. (1966) also fed groups of cows silage made
from Coastal Bermuda grass treated with endosulfan. The
maximum residue of endosulfan in the silage was 6.43 mg/kg
(dry basis), which appeared in the grass treated at 1 Ib
Al/acre. There were no detectable residues of endosulfan in
the milk between the groups of cows which received treated
silage and a control group of cows which received untreated
silage.
McCaskey and Liska (1967) examined the effect of pro-
cessing on the residues of endosulfan in milk. The investi-
gators were not able to detect any endosulfan in the milk of
cows fed up to 2,000 mg/day for 11 days. However, they did
detect 0.6 ppm endosulfan sulfate in a raw milk sample, but
the investigators did not state the treatment rate for the
cow which produced that sample.
The Food and Drug Administration (FDA), Department of
Health, Education and Welfare, monitors pesticide residues in
the nation's food supply through two programs. One program,
commonly known as the "total diet" or "market basket" program,
C-17
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involves the examination of food ready to be eaten. This in-
vestigation measures the amount of pesticide chemicals found
in a high consumption varied diet. The samples are collected
in retail markets and prepared for consumption before analy- ,
sis. The other program involves the examination of large
numbers of samples obtained when lots are shipped in inter-
state commerce to determine compliance with tolerances.
These analyses are complemented by observations and investi-
gations in the growing areas to determine the actual prac-
tices being followed in the use of pesticide chemicals
(Duggan, et al. 1971).
A majority of the samples collected in these programs
are categorized as "objective" samples. Objective samples
are those collected about which there is no suspicion of
excessive residues or misuse of the pesticide chemicals. All
samples of imported food and fish are categorized as objec-
tive samples even though there could be reason to believe
excessive residues may be found on successive lots of these
food categories.
Market basket samples for the total diet studies are
purchased from retail stores, bimonthly, in five regions of
the United States. A shopping guide totaling 117 foods for
all regions is used, but not all foods are represented in all
regions because of differences in regional dietary patterns.
The food items are separated into 12 classes of similar foods
(e.g., dairy products; meat, fish, and poultry; legume vege-
tables; and garden fruits) for more reliable analysis and to
C-18
-------
minimize the dilution factor. Each class in each sample is a
"composite". The food items and the proportion of each used
in the study were developed in cooperation with the USDA and
represent the high consumption level of a 16- to 19-year-old
male. Each sample represents a two-week supply of food
(Duggan, et al. 1971),
Surveillance samples are generally collected at major
harvesting and distribution centers throughout the United
States and are examined in 16 FDA district laboratories.
Some samples may be collected in the fields immediately prior
to harvest. Surveillance samples are not obtained in retail
markets. Samples of imported foods are collected as they
enter the United States (Duggan, et al. 1971).
The results of these FDA testing programs are intermit-
tently published in Pesticides Monitoring Journal. Pesticide
residues are analyzed by multi-residue methods. The residues
of endosulfan (total of at- and ^-isomers and sulfate) report-
ed in the total diet program are listed in Table 4. The
average endosulfan residues in raw agricultural products are
listed in Table 5. The average incidence and daily intake of
endosulfan based on these data for a six-year period are
listed as follows (Duggan and Corneliussen, 1972).
No. of Positive Daily
Year3/ composites examined composites (%) intake (mg)
1965
1966
1967
1968
1969
1970
216
312
360
360
360
360
^
1.6
0.3
0.8
4.2
5.3
^m
<0.001
<0.001
<0.001
0.001
0.001
^_/ Annual test period is from June of previous year to
April of year listed.
C-19
-------
TABLE 4
Endosulfan Residues in Total Diet Sample^/
Class of food
Number of composites
containing endosulfan Amount (mg/kg)
Time period of study
and source
o
i
NJ
O
Leafy vegetables
Garden fruits
Fruits
Leafy vegetables
Leafy vegetables
Garden fruits
Oils, fats, and shortening
Leafy vegetables
Potatoes
Garden fruits
Fruits
Leafy vegetables
Garden fruits
Fruits
Oils, fats, and shortening
Leafy vegetables
Potatoes
Garden fruits
Fruits
Fruits
Potatoes
Leafy vegetables
Garden fruits
1
3
1
1
1
1
1
5
3
1
15
2
2
5
6
1
7
6
0.016
<0.001, 0.002, and 0.006
0.014
0.003
0.014
0.008
0.0134
<0.001-0.042
0.004, 0.011
<0.001, 0.001, 0.002,
0.007
0.002, 0.010
<0.001-0.040
0.001-0.005
0.008-0.010
0.185
<0.001-0.063
<0.001, 0.007
<0.001, 0.061
<0.001-0.045
<0.001-0.006
<0.001
<0.001-0.008
<0.001
June 1965-April 1966
Duggan, et al. (1967)
June 1966-April 1967
Martin and Duggan (1968)
June 1967-April 1968
Corneliussen (1969)
June 1968-April 1969
Corneliussen (1970)
June 1969-April 1970
Corneliussen (1972)
June 1970-April 1971
Manske and Corneliussen (1974
June 1971-July 1972
Manske and Johnson (1975)
-------
TABLE 4 (Continued)
Potatoes
Leafy vegetables
Garden fruits
Fruits
Potatoes
Leafy vegetables
Garden fruits
Leafy vegetables
Garden fruits
4
17
4
4
6
3
3
5
2
<0.001-0.015
<0.001-0.439
<0.001-0.002
<0.001-0.007
<0.001-0.016
<0.001-0.012
<0.001
<0.001-0.022
<0.001-0.006
August 1972-July 1973
Johnson and Manske (1976)
August 1973-July 1974
Manske and Johnson (1977)
August 1974-July 1975
Johnson and Manske (1977)
n fy Total endosulfan (Ch-, &-, and sulfate)
M _/ Endosulfan sulfate only
-------
TABLE 5
Average Endosulfanfy Residues in Raw Agricultural Products
During 5-year Study (1964-1969)
Domestic
Average
No. of Incidence residue
Class of food
Large fruits
Small fruits
Leafy and stem
vegetables
Vine and ear
vegetables
samples %
6,763 0.8
2,695 2.0
13,864 4.9
8,072 1.4
(mgAg)
<0.001
<0.001
0.01
<0.001
Imported
Average
No. of Incidence residue
samples
2,495
496
153
1,791
% (mg/kg)
0.4 <0.001
2.4 <0.001
4.0 0.03
6.7 <0.001
Total includes &r- and 40-isomer and endosulfan sulfates
Source: Duggan, et al. (1971)
C-22
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A number of studies have been reported concerning the
presence of endosulfan residues in tobacco and tobacco pro-
ducts. The following paragraphs briefly summarize results
from these studies.
Dorough and Gibson (1972) reported the residue levels of
fc- and ^-endosulfan and endosulfan sulfate in three brands of
cigarettes purchased in the years 1970 to 1972. The residues
were determined by gas chromatography; this method has a de-
tection limit of 0.01 mg/kg. In 1970 and 1971 the residues
were all below the detection limit. The results for 1972
were as follows:
Endosulfan residue (mg/kg)
Brand
Regular A
Regular B
Filter B
Filter C
Menthol C
Average
^
0.01
0.01
0.01
0.01
0.01
0.01
&
0.12
' 0.14
0.10
0.09
0.10
0.11
Sulfate
0.27
0.30
0.21
0.25
0.30
0.26
Total
0.40
0.45
0.32
0.35
0.41
0.38
Domanski and Sheets (1973) reported the levels of endo-
sulfan residues (total for &- and ^-endosulfan plus endosul-
fan sulfate) in several varieties of 1970 U.S. auction market
tobacco. The results are presented in Table 6.
C-23
-------
TABLE 6
Endosulfan Residues, U.S. Auction Market Tobacco (1970)
Type
Flue-cured
Burley
Dark air-cured
Light air-cured
Dark fire-cured
Location
Tobacco Belt
Georgia-Florida
North-South
Carolina border
Eastern
Middle
Old
States
North Carolina
Tennessee
Kentucky
Tennessee
Kentucky
Maryland
Tennessee
Kentucky
Virginia
Total endosulfan
range
<0. 2-11.1
0.2-21.9
<0. 2-5.0
<0.2-4.5
<0.2-2.7
<0.2-3
<0.2
1.4-14.3
0.3-12.5
5.8-13.6
<0.2-3.3
1.4-4.6
2.8-11.9
0.4-6.5
Residue (mg/kg)3/
average
3.6
3.9
1.5
1.0
0.7
0.1
<0.2
8.6
5.7
8.5
1.5
3.2
6.0
3.3
*/ Total of &- and ^-endosulfan and endosulfan sulfate; the analytical
method was electron-capture gas chromatography
Source: Adapted from Domanski and Sheets (1973)
C-24
-------
Endosulfan residues on various U.S. tobacco products
were reported by Domanski, et al. (1973) for 1971 products
and by Domanski, et al. (1974) for 1973 products. Much of
the tobacco for the 1971 cigarette samples had been in stor-
age for two or more years. The results are presented in
Table 7.
Domanski and Guthrie (1974) reported endosulfan residue
levels (total for^- and ^-endosulfan plus endosulfan sulfate
and several other insecticides) in six brands of cigars pur-
chased in 1972. The residues were determined by gas chroma-
tography. The results for endosulfan were as follows:
Brand Total endosulfan residues (mg/kg)
1 0.64
2 0.26
3 0.63
4 0.36
5 0.49
6 <0.20
Average 0.41
Gibson, et al. (1974) reported residues of endosulfan in
Kentucky Burley tobacco for the years 1963 to 1972. The res-
idues for endosulfan included the two isomers and the sul-
fate. Endosulfan residues were not detected until 1968. The
residues in tobacco from auction warehouses in Kentucky and
residues in the Kentucky Burley tobacco pool were as follows:
From auction warehouse in In Kentucky Burley
Kentucky ^___ tobacco pool
YearResidue (mg/kgT Residue (mg/kg)
1968 0.23 Not reported
1969 0.30 0.86
1970 4.19 2.68
1971 4.60 Not reported
1972 4.10 Not reported
C-25
-------
TABLE 7
Endosulfan Residues on U.S. Tobacco Products (1971 and 1973)
Product
Cigarettes
Cigars
Little cigars
Smoking or pipe tobacco
Chewing tobacco
Snuff
Total endosulfan residues (mg/kg)fy
range (average)
1973^7
0.36-1.27 (0.83)
0.03-1.03 (0.37)
0.15-0.26 (0.22)
0.08-0.61 (0.37)
0.06-0.86 (0.36)
0.06-0.17 (0.12)
<0.2-0.4 (0.2)
<0.2-0.5 (0.2)
The analytical method was electron-capture gas chromatography
Source: Domanski, et al. (1973)
Source: Domanski, et al. (1974)
C-26
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Thorstenson and Dorough (1976) reported residue levels
of^- and ^-endosulfan and endosulfan sulfate in "reference"
and "alkaloid" cigarettes prepared by the Tobacco and Health
Research Institute for the years 1969 and 1974. The "refer-
ence" cigarette is a composite which reflects a blend of an
"average" domestic unfiltered cigarette; the "alkaloid" cig-
arettes were composites which contained blends of low-
nicotine Burley and flue-cured tobaccos. There were not
detectable residues of endosulfan in the 1969 samples. The
range and average endosulfan residues in the 1974 samples,
which consisted of one alkaloid and three reference cigar-
ettes, were as follows:
Residue (mg/kg)
Compound Range Average
^-Endosulfan 0 0
^-Endosulfan 0.4-0.7 0.5
Endosulfan sulfate 0.4-1.1 0.7
Total endosulfan 0.8-1.5 1.2
Schimmel, et al. (1977) reported on both short- and
long-term exposures of marine species to endosulfan. Pink
shrimp (Penaeus duorarum) did not show any uptake at all when
exposed to 0.089 ug/1 endosulfan for 96 hours, while grass
shrimp (Palaemonetes vulgaris) had 96-hour bioconcentration
factors ranging from 164 at 0.40 ug/1 (the highest concentra-
tion with 0 percent mortality) to 245 at 1.75 ug/1 (65 per-
cent mortality). Maximum bioconcentration factors after 96
hours for marine fish were 1,299 for pinfish (Lagodon
rhomboides), 895 for spot (Leiostomus xanthurus), and 1,344
for striped mullet (Mugil cephalus). The mullet was also
C-27
-------
used in a long-term exposure test for 28 days followed by 28
days in clean water. After exposure to 0.035 ug/1 endosulfan
for 28 days, the bioconcentration factors were 2,429 for
edible tissue and 2,755 for whole body. After two days in
clean water, endosulfan was not detected (limits of detection
= 0.01 ug/g in tissues). The investigators noted that in all
exposure tests endosulfan sulfate was the predominant and
often sole form of endosulfan found in the tissues.
Roberts (1972) studied the accumulation of endosulfan in
common mussels (Mytilus edulis) when exposed to levels of
0.1, 0.5, and 1.0 mg/1 endosulfan in seawater. The
concentration factors determined from these tests were as
follows:
Endosulfan Exposure period (days)
concentrations "T4" 2JT 4l 56 7T) 135 100 TT2
(mg/1) BToconcentratTon factors
0.1 13.0 17.0 13.5 19.3 22.5 16.1 17.0 17.0
0.5 4.7 5.8 4.9 8.3 6.9 7.0 7.8 11.0
1.0 2.8 3.3 3.7 3.9 6.5 7.4 7.1 8.1
Roberts (1972) also reporte'd a rapid fall in tissue residue
levels (1 to 2 mg/kg for all three exposure levels) within 58
days of removal from endosulfan-containing waters.
In further studies, Roberts (1975) investigated the dif-
ferential uptake of endosulfan by tissue of M. edulis.
Eighty mussels approximately 60 mm (2.4 in.) in length were
exposed to 0.1 mg endosulfan per liter in slowly flowing
seawater for 36 days, then transferred to clean seawater for
a further period of 23 days. Weekly samples of six mussels
C-28
-------
were taken for determination of endosulfan residues in the
digestive gland, the mantle plus gonad, the gills, and the
remaining tissue, consisting of pedal retractor muscles,
foot, and anterior and posterior adductor muscles.
Results showed that the major site of concentration of
endosulfan is the digestive gland. The approximate maximum
endosulfan residues found and the times at which they occur-
red (in number of days after initial exposure) were as fol-
lows, expressed as micrograms endosulfan (both isomers) per
gram of wet weight:
Digestive gland 6.1 after 7 days
Mantle and gonad 1.8 after 36 days
Gills 2.1 after 15 days
Remaining tissue 2.3 after 36 days
Mean residue level 2.5 after 36 days
Upon removal of the mussels to clean seawater, the endo-
sulfan residue levels initially declined fairly rapidly in
all tissues; the greatest decline occurred in the digestive
gland during the first 14 days of elution. During the final
six days of elution, the rate of residue loss was similar for
all tissues.
Ernst (1977) also evaluated the bioconcentration of
endosulfan in M. edulis in static tests. The inital concen-
tration of endosulfan was 2.05 ug/l» and it reached a steady
state concentration of 0.14 U9/1- The concentration factor
for -endosulfan calculated from the tissue levels of the
steady state concentration in the water was 600. The
half-life for elimination of the residue was calculated to be
33.8 hours.
C-29
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Roberts (1975) also conducted endosulfan uptake studies
with the scallop (Chlamys opercularis). In this species,
endosulfan concentrations in the digestive gland and in the
foot, and anterior and posterior adductor muscles were simi-
lar to those seen in M. edulis. However, the endosuLfan
level in the gills of M. edulis was almost five times that in
gills of C. opercularis, while the reverse was true in the
gonad and mantle tissues. The mean tissue residue levels for
both species, estimated from the summated values for the
separate tissues, were very similar despite the differences
in distribution between tissues.
Gorbach (1972) referred to an experiment in which gold-
fish (Carassius auratus) were exposed for five days to 1 ug/
1 14C-labeled endosulfan in water. The fish attained
endosulfan concentrations of 0.4 ug/g or a bioconcentration
factor of 400. It was also stated that the parent compound as
well as all metabolites were excreted within 14 days when the
fish were transferred to fresh water.
Oeser, et al. (1971) held goldfish for five days in a
test solution containing mean residues of 350 ug/1 i4C-
labeled endosulfan. The average ratio of body residues to
skin residues of 205:1 indicated that most of the endosulfan
was in the fish body, not the skin. After 14 days in fresh
water, the test fish had excreted 96 percent of the radioac-
tivity that had been absorbed in the test solution.
C-30
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Investigations by Schoettger (1970) with 14C-labeled
endosulfan indicated the compound is taken up and deposited
in various tissues of fish at varying rates. The liver and
gut (with feces) contained the most pesticide whereas the
heart, blood, gill, kidney, and brain showed slower uptake
rates; less was found in gut (empty), skin, and muscle. The
investigator noted that in general those tissues containing
relatively large amounts of blood contained the higher
concentrations of residues, with the exception of the gut and
feces. Radiotracer and chemical analysis techniques showed a
water-soluble metabolite of endosulfan in the bile of western
white suckers (Catostomus commersoni), northern creek chubs
(Semotilus atromaculatus), and goldfish. Schoettger (1970)
suggests that endosulfan degrades to its alcohol, which is
then conjugated with glucuronic acid and excreted with the
feces.
•
A bioconcentration factor (BCF) relates the concentra-
tion of a chemical in water to the concentration in aquatic
organisms, but BCF's are not available for the edible por-
tions of all four major groups of aquatic organisms consumed
in the United States. Since data indicate that the BCF for
lipid-soluble compounds is proportional to percent lipids,
BCF's can be adjusted to edible portions using data on per-
cent lipids and the amounts of various species consumed by
Americans. A recent survey on fish and shellfish consumption
in the United States (Cordle, et al. 1978) found that the per
capita consumption is 18.7 g/day. From the data on the nine-
teen major species identified in the survey and data on the
C-31
-------
fat content of the edible portion of these species (Sidwell,
et al. 1974), the relative consumption of the four major
groups and the weighted average percent lipids for each group
can be calculated:
Consumption Weighted Average
Group (Percent) Percent Lipids
Freshwater fishes 12 4.8
Saltwater fishes 61 2.3
Saltwater molluscs 9 1.2
Saltwater decapods 18 1.2
Using the percentages for consumption and lipids for each of
these groups, the weighted average percent lipids is 2.3 for
consumed fish and shellfish.
A measured steady-state bioconcentration factor of 12
was obtained for endosulfan using the common mussel which
probably contains about one percent lipids (Roberts, 1972).
A later study produced a BCF of 29 in only 14 days (Roberts,
1975). The BCF is much higher if the metabolite endosulfan
sulfate is included (Schimmel, et al. 1977). For the purpose
here a BCF of 12 will be used. An adjustment factor of
2.3/1.0 = 2.3 can be used to adjust the measured BCF from the
1.0 percent lipids of the common mussel to the 2.3 percent
lipids that is the weighted average for consumed fish and
shellfish. Thus, the weighted average bioconcentration
factor for endosulfan and the edible portion of all aquatic
organisms consumed by Americans is calculated to be 12 x 2.3
= 28.
C-32
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Inhalation
According to the American Conference of Governmental In-
dustrial Hygienists (ACGIH, 1977), the Threshold Limit Value-
Time Weighted Average (TLV-TWA) for endosulfan is 0.1 mg/m^.
The tentative value for the Threshold Limit Value-Short Term
Exposure Limit (TLV-STEL) is 0.3 mg/m^. The TLV-TWA is based
on a normal eight-hour workday or 40-hour workweek, day-after-
day exposure. The TLV-STEL is the maximum concentration to
which a worker may be exposed continuously for as long as 15
min without irritation, chronic or irreversible tissue changes,
or narcosis sufficient to increase the inclination to accident
or to affect self-rescue or work efficiency. Up to four such
exposures may occur per day provided at least 60 min elapse
between the exposures and provided the TLV-TWA is not
exceeded in the time lapses.
Apparently neither Occupational Safety and Health Admin-
istration (OSHA) exposure limits nor National Institute for
Occupational Safety and Health (NIOSH) recommended exposure
limits have been established for endosulfan (NIOSH, 1978a).
Further, a recent international comparison of hygienic stan-
dards for chemicals in the work environment did not list
standards for endosulfan (Winell, 1975).
Lee (1976) summarized the results of intensive ambient
air sampling at selected locations over the nation in which
samples were analyzed for pesticide residues. Samples were
collected during 1970, 1971, and 1972. The results of these
tests for endosulfan-containing samples are given in Table 8.
C-33
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Wolfe, et al. (1972) evaluated potential respiratory ex-
posure for a number of pesticides. Tests were conducted by
sampling spraymen operating tractor-drawn power air-blast
equipment as they applied pesticides to fruit orchards. En-
dosulfan was applied as a 0.08 percent spray. The estimated
respiratory exposure was 0.01 to 0.05 mg/hour (average 0.02
mg/hour).
Exposure to endosulfan was found by respirator pad anal-
ysis to be greater during mixing operations than in spraying
operations. With a five-min exposure time, 182,800 ng of en-
dosulfan were detected on the respirator pad during a mixing
operation; only 4,664 ng were detected during a 30-min spray-
ing operation (Oudbier, et al. 1974).
C-34
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TABLE 8
Summary of Endosulfan Residues In Air Samples from 16 States
State
Arkansas
Illinois
Kansas
Kentucky
Montana
North Carolina
All 16 states
Arkansas
Illinois
Kansas
Kentucky
Montana
No. of
Residue name samples
<3-Endosulfan
4-Endosulfan
rt-Endosulfan
rt-Endosulfan
d-Endosulfan
d-Endosulfan
e*-EndosuJ fan
<*-Endosulfan
4-Endosulfan
e*-Endosulfan
d-Endosulfan
^-Endosulfan
rf-Endosulfan
«A-Endosulfan
<*-Endosulfan
North Carolin»-«J-Endosul£an
All 16 states
tf-Bndosulfan
4-Endosulfan
72
53
64
68
48
54
-
Positive
samples
6.94
11.11
7.55
12.50
32.35
16.67
9.26
6.61
1.02
1970
Concentration (mg/mj)
ArJ thmetic
nean
1.1
2.4
2.2
5.5
159.4
13.9
0.7
13.0
0.2
1972
Mean of
positive
samples
15.5
22.0
28.8
43.8
492.8
83.5
7.2
111.9
22.0
Positive
Maximum No. of samples
value samples (%)
27.1 60 ND
54.5 ND
39.5 36 ND
70.7 49 ND
2,256.5 43 ND
211.7 36 ND
10.9 41 ND
2,256.5 - ND
54.5 ND
1971
Concentration (rag/m-*)
Mean of
Arithmetic positive Maximum
mean % samples value
ND ND ND
ND ND ND
ND ND ND
ND ND ND
ND ND ND
ND ND ND
ND ND ND
ND ND ND
ND ND ND
Concentration (mg/m-1)
64
59
65
66
69
64
-
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
-------
Tessari and Spencer (1971).analyzed air samples from hu-
man environments for pesticide residues. Nylon screens were
placed inside and outside the homes of 12 men occupationally
exposed to pesticides, including endosulfan, for a period of
one year, five days each month. Endosulfan residues were
found in 13 of 52 indoor air samples from the formulators1
households. In the positive samples, endosulfan residues
ranged from 0.22 to 4.52 ug/m2 of filter; the mean of the
positive samples was 1.77 ug/m2. The positive samples came
from only two households, and the householders in both cases
were formulators who had handled endosulfan. No endosulfan
residues were found in the outdoor air near any of the formu-
lators1 households, or in the indoor or outdoor air at the
farmers' households.
NRCC (1975) reported unpublished data (Boelens and
Frank, 1973) on endosulfan spray drift from an aerial spray
application of endosulfan to a tobacco field in Norfold Coun-
j
ty, Ontario, Canada (endosulfan formulation and rate of ap-
plication not given in secondary source.). Residues in var-
ious parts of the field were determined based on levels de-
tected in pans filled with water. Endosulfan levels detected
in the water within the field were 55.0 mg/1 between tobacco
rows; 8.5 mg/1 under plants in the rows; 20.0 mg/1 in an
opening in the field; and 0.01 mg/1 at the edges of the
field. No detectable (detection limit not reported) endosul-
fan residues were found at the edge of the field at the soil
surface. Water in an adjacent stream contained endosulfan
residues ranging from traces to 0.22 mg/1. Sediment from the
C-36
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stream contained 2.7 mg/kg of endosulfan in a sample col-
lected opposite the field's drainage and 0.23 and 0.37 mg/kg
in two other samples collected nearby. Aquatic mono-
cotyledonous plants contained 0.01 mg/kg.
Keil, et al. (1972) observed endosulfan spray drift in a
field test on tobacco in South Carolina. Three treatments of
endosulfan (formulation and AI content not given) at the rate
of 0.5 Ib Al/acre per treatment were applied by ground equip-
ment to single-row (12-ft) plots separated by guard rows.
Each treatment or control plot was replicated four times in a
completely randomized design. Samples of tobacco foliage
were collected for residue analysis at 11 posttreatment in-
tervals ranging from one day after the first application to
18 days after the third.
Even though the experimental design included guard rows,
endosulfan residues ranging from 0.037 to 0.679 mg/kg result-
ing from spray drift were found on plots treated with another
insecticide, and on untreated control plots. However, in
most instances (18 to 22 samples from plots not treated with
endosulfan), the residue from drift was less than the least
significant difference at the 95 percent probability level,
0.363 mg/kg endosulfan.
Dermal
The 1977 listing of TLV values showed a "skin" designa-
tion for endosulfan (ACGIH, 1977). This designation refers
to the potential contribution to the overall exposure by the
cutaneous route including mucous membranes and eyes, either
by airborne endosulfan or by direct contact with it.
C-37
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Wolfe, et al. (1972) also evaluated potential dermal ex-
posure of spraymen applying a 0.08 percent endosulfan spray.
The estimated dermal exposure was 0.6 to 95.3 mg/hour (aver-
age 24.7 mg/hour).
Possible intoxication due to the dermal exposure was
suggested by Kazen, et al. (1974) who analyzed hexane hand
rinsings and found that endosulfan persisted on exposed work-
ers' hands for 1 to 112 days after exposure.
PHARMACOKINETICS
Absorption
Undiluted endosulfan is slowly and incompletely absorbed
in the mammalian gastrointestinal tract (Maier-Bode, 1968).
However, when endosulfan is dissolved in a carrier vehicle
such as cottonseed oil, the oil and the insecticide are read-
ily, though not completely, absorbed by rats (Boyd and Dobos,
1969) and other mammals (Maier-Bode, 1968). The^-isomer is
more readily absorbed than the c^-isomer (Demeter, et al.
1977).
Alcohols, oils, and emulsifiers also accelerate the ab-
sorption of endosulfan by the skin (Maier-Bode, 1968).
Inhalation is not considered to be an important route of
uptake of endosulfan because of its low vapor pressure (9 x
10~3 mm Hg) (Maier-Bode, 1968).
When endosulfan is dissolved in chloroform and painted
on the shaven skin of rabbits, it is readily absorbed (Gupta
and Chandra, 1975).
A 1:1,000 dilution of endosulfan instilled on the con-
junctiva of rabbit's eyes caused neither pain nor subsequent
C-38
-------
inflammation, which was apparently because of rapid removal
by the lacrimal fluid (Hoechst, 1967a).
Distribution
After ingestion, endosulfan is first distributed to the
liver and then to the following organs: brain, heart, kid-
neys, lungs, spleen, testes, thymus gland, suprarenal glands,
mammary glands, skeletal muscles, and the remainder of the
gastrointestinal tract (Boyd and Dobos, 1969; Maier-Bode,
1968).
Two reports of individuals committing suicide by ingest-
ing endosulfan present some data regarding the distribution
of endosulfan in man. Demeter, et al. (1977) report on one
victim who ingested a preparation containing 12.4 percentcK-
and 8.1 percent ^-endosulfan. The order of distribution was
as follows: stomach contents > small intestine contents >
liver > kidneys > urine > blood.
The following table summarises the data reported by
Coutselinis, et al. (1978) from three suicide cases.
TABLE 9
Concentration Levels of Endosulfan in Biological Material
Case
1
2
3
Blood
(mg/100 ml)
0.4
0.8
0.7
Liver
(mg/100 g)
0.08
0.1
0.14
Kidney
(mg/100 g)
0.24
0.32
0.28
Brain
(mg/100 g)
0.025
0.03
0.028
Source: Coutselinis, et al. (1978)
C-39
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Metabolism and Excretion
The metabolism of endosulfan in mammalian species has
been widely investigated. The generalized metabolic pathway
for endosulfan in animals is given in Figure 1.
Demeter and Heyndrickx (1978) have detected endosulfan
sulfate as a metabolite in humans by analysis of two human
postmortem cases. Both were male, and both had taken a 20
percent endosulfan product by mouth within hours of death, in
one case under three hours. Endosulfan sulfate was not
detectable in blood or urine but was present in liver (3.4
mg/kg average), brain (0.5 mg/kg), and kidney tissue (0.4
mg/kg) .
No other information was found regarding the metabolism
of endosulfan (or endosulfan sulfate) in humans.
In a review by Matsumura (1975) a pathway for metabolism
in rats, mice, and insects was presented which differed some-
what from that given by Knowles shown in Figure 1. Matsumura
did not show the transformation of the ether to the hydroxy-
ether but indicated the hydroxyether was formed directly from
either the diol or the lactone (Matsumura, 1975).
The results of a study using 14C-labeled endosulfan in-
dicated the sulfate to be the metabolite most commonly pre-
sent in organs, tissues, and feces of rats whether dosed with
the
-------
CH2O
\
5=0
Cl
Cl
Cl
Endoiulfon eth«r
Endo»ulfan loetone
Source: Knowles (1974), Menzie (1974)
Figure 1. Metabolism of endosulfan in animals
C-41
-------
When the rats were administered the diol and the -hy-
droxyether, both were partially transformed to the lactone
and excreted in urine. The diol was also transformed to hy-
droxyether in the small intestine and in feces.
Feces usually had the highest radioactivity and must be
considered to be the principal route of elimination in the
•i
rat.
The metabolism of ^-4C-labeled endosulfan was also stud-
ied in BALB/C strain mice by Deema, et al. (1966). The 14C-
labeled endosulfan used was labeled in the hexachlorocyclo-
diene ring at carbons 5 and 6. The compound was composed of
58.3 percent 0^-endosulfan and 35.6 percent ^-endosulfan, 6.0
percent of the ether, and 1.0 percent of the alcohol.
Two male mice and four female mice were studied with
groups of two each being fed 0.30, 0.25, or 0.20 mg labeled
compound in 300 mg food. After 24 hours the activity of
label in 1 g of organ or excreta was greatest in feces
(98,452 cpm), followed by visceral fat (7,053 cpm), urine
(3,746 cpm), liver (2,883 cpm), kidney (1,390 cpm), brain
(424 cpm), respired CC>2 (302 cpm), and blood (92 cpm).
Total recovery of the labeled endosulfan was approximately 65
percent.
Purified unlabeled endosulfan was also fed at 0.3 mg/
mouse in a 300 mg food pellet. After 24 hours large amounts
of endosulfan sulfate were found in the liver, small intes-
tine, and visceral fat with a trace in skeletal muscle and
-------
appeared to be identical with endosulfan alcohol was detected
in urine.
When mice were fed only the ^-isomer of endosulfan, the
material was detected in the stomach, small intestine and
feces although endosulfan sulfate was detected in the liver,
small intestine, visceral fat and feces. Endosulfan alcohol
was found in urine. Neither the parent compound nor any of
its metabolites were detected in the brain.
When the $-isomer was fed, endosulfan sulfate was found
in the liver, kidney, small intestine, muscle, and visceral
fat. The alcohol was detected in the urine, but neither the
^-isomer nor any metabolites were detected in the brain.
When ten mice were fed diets containing 10 mg/kg puri-
fied endosulfan for 28 days, endosulfan sulfate was detected
in the liver and visceral fat of all animals although lower
amounts were detected than in organs of other test mice 24
hours after they had been fed a single 0.3 mg dose. Endosul-
fan isomers or metabolic products were not detected in the
brain, but a product having the same retention time as endo-
sulfan alcohol was detected in the urine. When the feces
were analyzed, both isomers, endosulfan sulfate, endosulfan
alcohol and endosulfan ether were detected.
Endosulfan alcohol was detected in the urine of animals
fed either endosulfan sulfate, endosulfan ether or endosulfan
diol.
The principal metabolic products produced in the mouse
under the conditions of this study were endosulfan sulfate
and endosulfan alcohol (Deema, et al. 1966).
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Dogs (unspecified breed or number of each sex) were
administered C^- and ^-endosulfan for 28 days at 0.35 and 1.75
mg/kg/day (FMC, 1963). Upon analysis only traces of tfS- and
^-endosulfan were detected in the urine (0.02 to 0.1 ppm),
but large amounts (13 to 25 percent of the endosulfan fed)
were detected in the feces.
In a study with two East Frisian milk sheep, radiola-
beled endosulfan (65 percent
-------
After 40 days the organ with the highest concentration
of radiolabel (0.03 ug/g) was the liver.
The investigators noted that no fat-soluble metabolite
other than endosulfan sulfate was detected in the milk of the
test animals and that no major metabolite was retained in fat
or in the organs for long periods of time (Gorbach, et al.
1968) .
In another study, between 0.1 and 0.2 mg/1 endosulfan
sulfate was detected in the milk of cows that had been given
2.5 mg/kg<*-endosulfan, 2.5 mg/kg ^-endosulfan, and 5 mg/kg
endosulfan sulfate in the feed for 30 days (FMC, 1965). Less
than 0.005 mg/liter endosulfan sulfate was detected in the
milk 20 days after administration of the insecticide was
stopped.
The half-life of endosulfan in the milk of cows that
survived poisoning was reported to be 3.9 days (Braun and
Lobb, 1976). These residues were present primarily as endo-
sulfan sulfate. The endosulfan isomers were detectable in
milk for six days in one animal and 13 days in another, with
a detection limit of 0.001 mg/1. Endosulfan sulfate residues
were detected for 35 days in both animals. Blood contained
detectable amounts of the sulfate metabolite (0.025 mg/1) for
one day after exposure. Parent isomers were not found in
blood.
In sheep given single oral doses of !4C-labeled endosul-
fan at 14 mg/kg, the half-life of radiolabeled endosulfan in
the feces and urine of sheep was reported to be about two
days (Kloss, et al. 1966).
C-45
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Borough, et al. (1978) studied the fate of endosulfan in
female rats given the insecticide by esophageal intubation.
Five days after a single radiolabeled dose, 88 percent of the
^-isomer and 87 percent of the /9-isomer were recovered in the
urine (13 percent) and the feces (75 percent). Two days
after a single dose was given to rats with cannulated bile
ducts, 47 percent of the c*-isomer and 29 percent of the^-
isomer were secreted in bile.
After another group of these rats had eaten diets con-
taining endosulfan for 14 days, the half-life of the residues
was determined to be approximately seven days.
The last group of rats was fed 5 mg/kg endosulfan meta-
bolites (the sulfate, diol, -hydroxyether, lactone, and
ether derivatives) for 14 days. The organs containing the
greatest amounts of endosulfan derivatives were the kidneys
(1 ug/g) and the liver (3 ug/g)«
EFFECTS
Acute, Sub-acute, and Chronic Toxicity
Values for the LDsg of technical endosulfan (an —2:1
mixture of (k- and ^-endosulfan) via oral, intraperitoneal,
and dermal routes are shown in Table 10. The oral LD5Q for
technical endosulfan for rats ranged from 18 to 121 mg/kg,
and varied with the technical material or formulation used,
C-46
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TABLE 10
Acute Toxicity of Endosulfan
Tent AiilMal
(•ex) (airaln)
Hal (-) (Siirajjuc-U«ul«y)
Nut, H (Sheniian)
Hat, f (Shoruaii)
Hat (-) (-)
H.il, M (MUtar)
Hal (-) (-)
H»l (-) (-)
Hit, M (-)
Hat, M (-)
Hat, F (-)
Hal, F (-)
0 Hal (-) (-)
1 Hat (-) (-)
4»>
-J
Kit , M (She man)
Ril, t (ahenuan)
Kndonulfan or
fonunlailon
Purified
Technical
Technical
Technical
Technical
a-eiidoaulfan
p-cndocul fan
Technical
Technical
Technical
Technical
HOB 2671 (201 Al)
HOE 2671 (sol.
pouder)
Technical
Technical
Solvent (carrier)
Com oil
Peanut oil
Peanut ol I
-
-
-
-
Alcohol
I0i alcohol In peanut oil
Alcohol
|OZ alcohol lu peanut oil
Alcohol
Alcohol
Xylena
Xylene
Number of anliaala
per toat group
—
60 total
70 total
-
-
-
-
16/lreatMnt group
16/trantBcut group
16/treuluent group
lo/ treatment group
6/ treatment group
4/trantucnt group
60 total
70 total
Route of
adulnlnir illon
Ora
Ora
Ora
Ora
Or«
Ora
Ora
ntrapoiltonea
ntrapcrltonea
ntrapurl tonua
ntraporltonea
utraperltoiiea
nt rapurltonea '
llcnul
Denial
ID5Q (ag AI/kg^H'
40-50
4) (41-40)
18 (15-21)
35
121 (i 16)
76 .g/kg
240 «8/kg
46. (16.4-51.5)
89. (7J-107.4)
22. (18.6-26.9)
48. (16.4-51.8)
(6.1-10.1)
11. (9.5-19.3)
110 (104-161)
74 (58-94)
Source
UmJqulst and Oaloa (1957)
(.alnen (1969)
Calms (1969)
Jonra et al . (1968)
Boyd and Oabos (1969)
lloechst (19671.)
lloechat (I9u7b)
Gupta (19)6)
Gupta (19)6)
Gupta (19)6)
Gupta (19)6)
Undle (1956)
Lendle (1956)
Calnea (1969)
Colncs (1969)
Hal , II <-)
limit.,., N (-)
Muilbu, M (-)
lloilbc, I (-)
M.MIbC, f (-)
Rulikll, t (Albino)
Hakbll, t (Albino)
Inhalalton, 4 liaura 35O
Technical
Technical
Technical
Technical
technical ('HID
Tuchnlcal (> 911)
Alcohol
10X alcohol In peanut oil
Alcohol
Itft alcohol In peanut oil
tihlnroforu
Chloroforui
16/trcatroent group
16/trc.iiiacnt group
16/lreatnent group
l6/treaL»Liit group
4/lrcaluicnt group
4/treataM.iit group
Intraperltoneal
Intraprrltoncal
Intruperltoneul
Int ra|>url tonua I
Denial
Ucnnal
6.9 (5.4-8.9)
12.6 (9.4-16.8)
7.5 (5.1-10.1)
11.5 (10.6-16.8)
182 (+ 36)
161 (T 21)
Ely et Hi. (1967)
Gupta (1976)
Gupta (19)6.)
Gupta (19)6)
Gupta (19)6)
Gupta anil (.1, mdra (l'')5)
Gupta iiinl Chandra (19)5)
£/ Al - Active Ingredient.
-------
the kind of vehicle used for administration, and the sex of
the animal. These data indicate that endosulfan by oral,
intraperitoneal, or dermal route is more toxic to female rats
than to males regardless of the kind of vehicle used for ad-
ministration (ACGIH, 1971).
Some difference in toxicity occurs whenever different
vehicles are used as the carrier. Lendle (1956) quoted an
LD5Q of only 8 mg/kg when endosulfan was dissolved in ethyl
or isopropyl alcohol and given intraperitoneally to rats, but
similar animals treated with endosulfan in cottonseed oil
have an 1-05Q as high as 48.6 mg/kg.
In another study (Gupta, 1976), male rats given endosul-
fan in alcohol exhibited an LD$Q at 46.7 mg/kg, but similar
males given the material in ten percent alcohol in peanut oil
exhibited an LD5Q at 89.4 mg/kg. While the amount of endo-
sulfan necessary to yield an LD$Q was less for female rats,
the twofold difference between administration in the two
different vehicles remained the same.
Boyd and Dobos (1969) estimated the largest nonlethal
dose (LD0) to be 60 mgAg and the smallest totally lethal
dose of endosulfan (LDjog) to be 180 mg/kg in Wistar rats.
Truhaut, et al. (1974) demonstrated that there were dif-
ferences in the toxicities of endosulfan to different rodents:
the LD5Q of 96 percent pure endosulfan administered orally to
rats and hamsters was 64 + 4 mg/kg in the rat and 118 +_ 16
mg/kg in the namster. The maximum dose without fatality was
40 mg/kg for the rat and 70 mg/kg for the hamster. Biochemi-
cal measurements, or effects of endosulfan dosing on enzyme
C-48
-------
levels, showed that in the hamster, endosulfan inhibited
cholinesterase significantly, whereas there was no effect on
rat cholinesterase. On the other hand, the activities of
enzymes GPT and LDH were significantly elevated by endosulfan
dosage in the rat, but in the hamster they were unaffected.
The difficulty in extrapolating LD$Q data from one ani-
mal to another was demonstrated in a study by Li, et al.
(1970), who estimated (based on rat data) that 12.5 mg/kg
would be an acceptable dose for (Brown-Swiss and Holstein)
dairy cattle. Within ten hours of dosing, however, the two
treated cows were in an extreme state of excitation, and six
days after dosing one of the animals (Brown-Swiss) died.
The effects of accidental dermal exposures of cattle to
endosulfan were reported by Thompson (1966). Two hundred and
fifty cattle (breed, age, and sex not reported) were acci-
dently sprayed with a five percent endosulfan miscible oil
concentrate diluted 1 to 300, giving a wash concentration of
approximately 0.12 percent endosulfan. The cattle were
sprayed early in the morning. Signs of toxicity were noted
in 50 of the 250 animals by about noon. Four cattle were
dead by 4 p.m. and six more died by the next morning. The
symptoms of exposure were those of hyperexcitability
(Thompson, 1966).
An accidental poisoning of three cows with endosulfan
was reported, which occurred when the animals ate grass which
had been sprayed with an endosulfan emulsion spray (reported
as 35 percent endosulfan) ten months before. Analysis of the
organs of one of the animals with gas chromatography showed
C-49
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the presence of ^-endosulfan at -7 to 9 ugAgr ^-endosulfan at
3.5 to 4.5 ug/kg, and metabolites as high as 9 mg/kg (Schmid-
lin-Meszaros and Romann, 1971).
Four of five crossbred male and female calves, weighing
60 to 170 kg, died within 24 hours after being dusted with a
four percent dust formulation of endosulfan. Symptoms of
toxicity included frenzied activity, violent convulsions,
blepharospasm, and overall extreme hyperexcitability. One of
the animals was necropsied, and no gross lesions were seen.
Laboratory analysis revealed 0.73, 3.78, and 0.10 mg/kg endo-
sulfan in the brain, liver, and rumen contents, respectively
(Nicholson and Cooper, 1977). This report indicates excel-
lent skin absorption in cattle, and probably a toxic dosage
much lower than that reported for rats, for which 110 mg/kg
is an experimental fatal dose (Dreisbach, 1974). Milk and
tissue were also analyzed from another dairy herd which was
exposed to endosulfan; 9 of 18 animals exposed died (Braun
and Lobb, 1976). Liver, kidney, and muscle tissue contained
endosulfan sulfate at a level of 4.2, 1.1, and 0.6 mg/kg, re-
spectively. Milk from one of the survivors contained 1 ug/kg
endosulfan sulfate at the end of five weeks, at the time a
blood sample contained 0.025 mg/kg endosulfan. The symptoms
of exposure were like those described in the first report.
The signs of toxicity observed in rabbits were similar
to those in rats and mice, the onset occurring three to six
hours after exposure. Hyperexcitability, dyspnea, decreased
respiration, discharge from the eyes, and tremors were fol-
lowed by convulsions. The convulsions appeared at intermit-
C-50
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tent or regular intervals. The animals preferred to rest on
the sternum with the forelimbs extended. Eventually the
animals lost response to painful stimuli. This loss first
occurred in the hindlimbs and then spread to the forelimbs
followed by loss of motility, loss of corneal reflex, a deep
coma> and death (Gupta and Chandra/ 1975).
In cattle dermally exposed to endosulfan the signs of
toxicity consisted of listlessness, blind staggers, restless-
ness, hyperexcitability, muscular spasms, goose-stepping, and
violent "fits" (Thompson, 1966).
Three other reports of accidental animal poisoning (spe-
cies not specified) describe the toxic effects of endosulfan
exposure (Panetsos and Kilikidis, 1973; Utklev and Westbye,
1971; Schmidlin-Meszaros and Romann, 1971, all cited by
Demeter and Heyndrickx, 1978). The effects reflected an
induced neurotoxicity and were roughly analogous to those in
endosulfan-poisoned humans.
A survey by California veterinarians reported on the
occurrence of domestic animal poisoning by organochlorines,
including the death of calves following contamination of feed
bunks with endosulfan. No specific instances or dose levels
were reported, but signs of poisoning and treatment were
tabulated (Maddy and Riddle, 1977). Signs of poisoning in-
cluded apprehension, hypersensitivity and spasms of the eye-
lids and front quarters progressing to the hind quarters;
these spasms may be continuous or intermittent. Clonic-tonic
seizures, loss of coordination, circling frontward or back-
ward, and abnormal posturing is seen. The animal may become
C-51
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comatose. The veterinary treatment emphasizes agents to con-
trol particularly violent neuromuscular activity in severe
poisonings (Maddy and Riddle, 1977).
Ely, et al. (1967) report that the inhalation four-hour
LC5Q of endosulfan was 0.35 mg/1 for male rats. Under simi-
lar test conditions the four-hour LC5Q for female rats was
0.08 mg/1. Whether these values are from work done by Ely,
et al. or are quoted from some other report, however, is not
clear. Details on procedures, numbers of animals, etc., were
not given.
Gupta and Chandra (1975) studied the eye irritation
properties of endosulfan. When aqueous suspensions of 5, 10,
and 20 percent endosulfan were instilled into one eye each of
six rabbits (two per group) no irritation or congestion was
observed in any of the animals.
A 1:1,000 endosulfan dilution instilled in rabbit eyes
caused neither pain nor subsequent inflammation (Hoechst,
1967a).
Skin irritation and skin sensitization studies have ap-
parently not been made with endosulfan, although one report
notes that the skin of rabbits treated dermally with endosul-
fan at 100 mg/kg did not exhibit any cutaneous abnormalities
(Gupta and Chandra, 1975).
Signs of poisoning in dogs dosed orally with 200 and 500
mg/kg body weight were increased saliva formation, vomiting,
and tonic and clonic cramps (Hazleton Laboratories, 1967).
Signs of toxicity in endosulfan-exposed cattle have been
described earlier in this section.
C-52
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Gross necropsy of rats fed .endosulfan at near the LD5Q
range (see Table 10) revealed congestion of the brain and an
acute gastroenteritis. Dark reddish areas were often seen in
the kidneys, liver, spleen, and thymus. The skin was of nor-
mal appearance. Edema of the interstitial tissue of the tes-
tes was noted.
A loss of organ weight was observed in most animals, but
significantly so in cardiac stomach, kidneys, liver, skin,
spleen, testes, and thymus (Boyd,and Dobos, 1969).
Gupta and Chandra (1975) report that following an acute
dermal exposure of rabbits to endosulfan at 100 mg/kg of body
weight, necropsy revealed congestion in the kidneys, perito-
neum, and the muscles underlying the skin. No other gross
pathological conditions were observed. Microscopic examina-
tion of the liver revealed marked congestion and dilation of
sinusoids. In some of the lobules hepatocytes were observed
undergoing degenerative changes around central veins. Sec-
tions of the kidneys from treated animals showed groups of
glomeruli with shrunken tufts and thickened Bowman's capsules.
Occasionally the epithelium of the proximal convoluted tubules
were necrotic and desquamated. The adrenals of treated ani-
mals exhibited cell disruption, foamy cytoplasm, and eccen-
tric nuclei in the zona reticularis.
Necropsy of cattle that died following an accidental
(dermal) exposure to endosulfan did not reveal any great
pathological changes, although congestion and edema of the
lungs along with froth in the trachea were observed (Thomp-
son, 1966).
C-53
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The liver was the principal target, with increased weight
and an apparent increase in drug metabolizing enzymes (Gupta
and Gupta, 1977a, 1977b). Rats that were dosed on either 7
or 15 consecutive days with 2.5 or 5.0 mg/kg technical endo-
sulfan showed liver effects. Neither testes nor adrenals of
the endosulfan-treated animals differed in weight from the
controls.
The kidney, stomach, and intestine of fish were adverse-
ly affected by exposure to a 35 percent emulsifiable concen-
trate formulation of endosulfan at levels of 0.4 and 0.8
ug/lf and the same dose also severely damaged the liver
(Amminikutty and Rege, 1977; 1978). Acute treatment involved
observation of histological change that occurred in fish 96
hours after the formulation was added to the fish water. The
96 hour LC5Q was 1.6 ug/lr and renal tubular cells were
affected. Both stomach and intestinal mucosa were severely
damaged. Fish, chronically exposed to levels of 0.4 and
0.53 ug/1 for 16 weeks showed hyperplasia of the kidney and
necrosis of intestinal mucosa cells (Amminikutty and Rege,
1978) . The same dose levels and time produced vacuolated and
ruptured hepatic cells, as well as frequent total destruction
of pancreatic islet cells (Amminikutty and Rege, 1977).
A toxic effect unreported in other studies, testicular
atrophy in male Osborne-Mendel rats, was seen in the recent
carcinogenicity bioassay (Weisburger, et al. 1978). Testicu-
lar pathology occurred in 18/47 (38 percent) of the group
receiving 445 mg/kg endosulfan of 98.8 percent purity in the
diet, and in 24/47 (51 percent) of the group receiving 952
C-54
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mg/kg. The pathology was characterized by degeneration and
necrosis of the germinal cells lining the seminiferous tu-
bules. Three of 19, or 16 percent of the control rats had
testicular atrophy in this study. Male mice of the B6C3F1
strain, receiving 6.9 and 3.5 mg/kg in the diet, in the same
study, showed a slight indication of testicular atrophy with
pathology in 3 of 50 high dose and 2 of 50 low dose. Control
mice had neither testicular inflammation nor atrophy.
Protein-deficient male Wistar strain rats were reported
to be four times as susceptible to the toxic effect of tech-
nical grade endosulfan as rats having adequate protein nutri-
tion. The toxicity of the pesticide was determined after the
rats had been fed for 28 days on a purified diet low in pro-
tein. Test animals were compared to rats on the purified
diet with normal protein and to rats on standard laboratory
chow.
With the purified diet containing no additional protein
the LD5Q in rats was 5.1 ^ 1.4 mg/kg. At dietary protein
levels of 3.5, 9.0, 26.0, and 81 percent (28 days' feeding)
endosulfan LDsg's in rats were 24 +_ 10, 57 +_ 4.0, 102 _+ 16,
and 98 ^ 7 mg/kg, respectively. The LD5Q value for endosul-.
fan when given in standard laboratory chow was 121 +_ 16 mg/kg
(Boyd and Dobos, 1969; Boyd, et al. 1970).
Toxicity of endosulfan sulfate to mammals is about the
same as the parent compound. However, the endosulfan
alcohol, hydroxyether, and lactone have LDso's ranging from
i
150 to 1,500 mg/kg in the rat (Gorbach, 1972).
C-55
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Dorough, et al. (1978) determined the acute oral toxici-
ties of endosulfan and its apolar metabolites to female
albino mice. The approximation method used results in values
that correlated very closely with LD 50values. The most
toxic compounds were endosulfan sulfate (8 mg/kg), -endosul-
fan (11 mgAg)/ and -endosulfan (36 mgAg). With these com-
pounds, no symptoms of poisoning were seen until the lethal
dose was almost reached, and the lethal doses caused convul-
sions and death within one hour. Four other metabolites were
tested: Endosulfan -hydroxyether, endosulfan lactone, endo-
sulfan ether, and endosulfandiol, with acute lethal doses of
120, 120, 270, and over 2,000 mg/kg, respectively. For ease
of comparison, these values are tabulated:
Approximate Lethal Dose of Endosulfan
and Apolar Analogs to Mice
Compound Dose (mg/kg)
^-endosulfan 11
^-endosulfan 36
Endosulfan sulfate 8
Endosulfan -hydroxy ether 120
Endosulfan lactone 120
Endosulfan ether 270
Endosulfandiol >2,000
Source: Adapted from Dorough, et al. (1978)
Rats were reported to tolerate endosulfan at oral doses
of up to 3.2 mg/kg/day for three months without observed
injury (Czech, 1958).
The no-effect level for dogs was considered to be 30
mg/kg feed (/~0.75 mg/kg/day) (FMC, 1967).
A no-effect level for endosulfan in rats was studied
with respect to induction of microsomal liver enzymes (Den
C-56
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Tonkelaar and Van Esch, 1974). The activities of aniline
hydroxylase, aminopyrine demethylase, and hexobarbital oxi-
dase in experimental groups each consisting of six Wistar
male rats were compared with those of six control animals.
Results from aniline hydroxylase induction studies indicated
that when endosulfan was fed in the diet at 200 mg/kg for two
weeks the activity of the enzyme was 123 percent of the con-
trol (statistically greater); at 50 mg/kg the activity of the
enzyme in treated animals was nearly the same as the control
(slightly less). Treatment with endosulfan at a dietary
level of 200 mg/kg also statistically increased the activity
of aminopyrine demethylase but not the activity of hexobarbi-
tal oxidase. The no-effect dietary level for endosulfan for
rats was considered to be 50 mg/kg.
A six-week toxicity study, dosing 98.8 percent pure en-
dosulfan in the diet, was performed at five dose levels on
B6C3F1 mice, five males and five females per dose, and a sim-
ilar number of Osborne-Mendel rats (Weisburger, et al. 1978).
Concentrations of endosulfan in the rat group were 178, 316,
562, 1,000 and 1,780 mg/kg, and in the mouse groups 3.2, 5.6,
10, 18, and 32 mg/kg. Animals were dosed six weeks, then ob-
served two more weeks while on regular diet. A control group
for each species received the vehicle and normal lab chow.
In male rats, a nine percent depression in mean body
weight occurred at 562 mg/kg, and a 20 percent depression at
1,000 mg/kg. No depression in body weight as a function of
dose occurred in female rats. In both sexes of mice, depres-
C-57
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sion in mean body weight was observed at concentrations of
5.6 mg/kg and above.
Deaths and the endosulfan dose levels:
Rats: 3/5 males, 1,780 mg/kg
1/5 females, 316 mg/kg
4/5 females, 562 mg/kg
Mice: 1/5 males, 10 mg/kg
1/5 females, 5.6 mg/kg
Weight gain of young female rats fed either 5 or 50
mg/kg endosulfan in the diet for 15 days was used as an indi-
cator of the compound's effect on animals exposed to the in-
secticide subacutely. Both groups gained weight at the con-
trol rate, and there was no difference in the weight of livers
or kidneys of endosulfan-exposed rats when compared to control
(Dorough, et al. 1978).
The compounds used in this test were purified - and
endosulfan added as an acetone solution to ground animal
feed. Feed was checked by extraction and chromatography when
freshly prepared and after remaining in the feeding cup 24
hours. The four feeding groups were:
13 rats, ^-endosulfan isomer-5 mg/kg
13 rats, ^-endosulfan isomer-5 mg/kg
4 rats, ^-endosulfan isomer-25 mg/kg
4 rats, 7:3 mixture of ^:d-endosulfan-25 mg/kg
Dogs were reported to "tolerate" endosulfan at doses up
to 0.75 mg/kg for one year (Hazleton Laboratories, 1959a).
C-58
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Oral doses of about 10 and -100 mg/kg endosulfan in the
diet were administered to rats for two years (Hazleton
Laboratories, 1959b). Low survival of females and reduced
testis weight in males were seen at the low dose. Consistent
histopathological findings were apparent at the high dose
level, which produced renal tubular damage and some hydropic
change of the liver.
Synergism and/or Antagonism
The two human fatalities reported by Demeter and Heyn-
drickx (1978) both involve endosulfan ingested with alcohol
(although dimethoate was also in one formulation). The
authors suggest that synergism between alcohol and endosulfan
is likely and they reference the statements of Lendle (1956)
who demonstrated an increased gastrointestinal absorption of
endosulfan in the presence of alcohols.
The acute toxicity of a diethylphosphorothioate (bromo-
phos-ethyl) was examined when dosed with endosulfan for syn-
ergistic effects. A group of ten rats was orally dosed with
1/2 LD5Q of endosulfan, or 24 mg/kg, at the same time they
received 1/2 LD5Q of bromophos-ethyl. The mortality expected
was 5/10 or 50 percent; 6/10 died within the one week obser-
vation period, which indicates no synergistic activity occur-
red (Muacevic, 1973).
Endosulfan was reported by Gupta and Gupta (1977a) to
decrease the pentobarbital-induced sleeping time in endosul-
fan-treated rats. Animals receiving the two higher doses of
endosulfan showed significant increases in time to sleep in-
duction and shortening of the sleeping time. Although the
C-59
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blood and brain concentrations of pentobarbital were signifi-
cantly reduced at 30 min (reflecting the reduced response ob-
served) , there were no differences in concentrations of pent-
obarbital in blood and brain in control and treated animals
when the rats awoke. This indicated to the authors that the
inhibitory effect on pentobarbital by endosulfan is not due
to a change in the sensitivity of the brain, but could be due
to enhanced metabolism of pentobarbital.
The influence of endosulfan on rat hepatic drug metabo-
lizing enzymes and lipid peroxidation was also measured to
define how endosulfan modifies the action and metabolism of
other compounds by affecting the mixed function oxidase sys-
tem (Agarwal, et al. 1978). A marked increase in the activ-
ity of aminopyrine-N-demethylase, aniline hydroxylase and
tyrosine amino-transferase was found, as well as an increase
in spontaneous lipid peroxidation. The increases were all
dose dependent at the levels of 2.5 and 5.0 mg/kg (Agarwal,
et al. 1978). The increase of the demethylase as well as the
hydroxylase enzyme suggests that endosulfan is a nonspecific
inducer of drug metabolism.
Teratogenicity
Technical grade endosulfan was tested for teratogenic
and embryotoxic effects in rats by Gupta, et al. (1978). The
insecticide was suspended in corn oil and given orally from
day six through day 14 of gestation in doses of 0.0, 5.0, and
10.0 mg/kg. On day 21 of gestation, both dams and fetuses
were examined for pathology. There was a significant increase
in fetal mortality and resorption sites in endosulfan-treated
C-60
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rats: control rats had 5.5 percent resorption without any
dead fetuses, whereas endosulfan-treated rats had 20 to 22.8
percent resorptions. No malformations of any significance
were noted in 463 fetuses from 59 dams. The authors conclude
that the study demonstrated no teratogenic effect, but that
the administration of endosulfan to pregnant rats produced a
dose related increase in maternal toxicity, which they attri-
buted to a possible effect on the female sex hormones (Gupta,
et al. 1978).
Pure endosulfan was tested for embryotoxicity in the
fertile eggs of White Leghorn chickens at levels of 10 to 500
mg/kg. Injections were made to the center of the yolk using
corn oil or acetone as the carrier. At 100 mg/kg, endosulfan
in acetone reduced hatchability by 54 percent compared to
controls; 100 mg/kg endosulfan in corn oil reduced hatchabil-
ity by 24 percent compared to controls (Dunachie and
Fletcher, 1969). Endosulfan at 500 mg/kg in acetone showed
53 percent hatchability compared to controls.
In similar studies, Smith, et al. (1970) evaluated the
embryotoxic effects of endosulfan on chickens. When 72 eggs
per treatment and six treatment levels were studied (0.07 to
1.5 mg/egg yolk infection) hatchability was reduced from the
zero control level of 80.0 to 77.3 percent at 1.5 mg/egg. At
the lowest concentration tested percent hatchability was not
affected (Smith, et al. 1970).
In other tests 5 mg endosulfan per egg reduced hatch-
ability to 60 percent (Dunachie and Fletcher, 1966).
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Lutz and Lutz-Ostertag (197.2) conducted a study in which
eggs from hens of mixed breeding (Rhode Island Red-Wyandotte
White and Rhode Island Red-Wyandotte White—Light Sussex
crosses) were dipped into or sprayed with endosulfan in alco-
hol or acetone solutions at concentrations from 0.5 to 5 per-
cent. Following treatment the eggs were incubated normally.
Gonads from male and female chick embryos at days eight and
nine of incubation were explanted on agar medium to which
three drops of a 0.5 to 1.0 g/1 solution of endosulfan were
added.
These investigators reported that the spray and dip
treatments of the eggs resulted in alterations in the gonads
of the embryos in both males and females. The cultured
gonads underwent hypertrophy and became vacuolized; thus,
there was a tendency to sterility of the gonads.
Lutz-Ostertag and Kantelip (1970; 1971) performed simi-
lar experiments on quail eggs (Coturnix coturnix japonica).
They concluded that endosulfan had no teratogenic effect on
the quail at the doses employed, but the male and female
embryos were sterilized, and, according to the authors, was
due to the antimitotic toxicity exhibited by endosulfan.
Mutagenicity
Endosulfan, of unreported concentration, purity, and
other detail, was positive as a base-pair substitution muta-
gen in direct Salmonella tests (without microsomal activa-
tion). The microbiological tests employed the Salmonella
typhimurium histidine auxotrophs TA1535, TA1536, TA1537, and
TA1538 (Adams, 1978).
C-62
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Neither isomer of endosulfa.n, nor metabolites endosulfan
ether and endosulfan sulfate were active in the Salmonella
mutagenicity test with or without the S-9 liver homogenate.
Metabolites endosulfan diol, b»-hydroxyether and the lac tone
severely inhibited bacterial growth even at 10 ug per plate,
so the Ames test on these compounds produced inconclusive
results (Dorough, et al. 1978). All compounds were screened
using the four Salmonella typhimurium strains TA98, TA100,
TA1535, and TA1978 following dose response tests at 10, 100,
500, and 1,000 ug per plate, and were compared to a positive
control, 2-acetylaminofluorene.
Endosulfan gave negative results when tested for muta-
genicity in Saccharomyces cerevisiae (mitotic gene conversion
at the ade two and trp five loci), Escherichia coli (forward
mutation to streptomycin resistance at the str A gene locus),
and Serratia marcescens strains a 21 and a 742 (back mutation
to prototrophy). Test dose levels were not given (Fahrig,
1974).
The most relevant tests for predicting risk to humans
are positive results from jLn vivo mammalian tests which assess
the chemical's tendency to produce germ cell mutations. The
heritable translocation test in rodents is probably the best
test to show chromosomal rearrangements, although the diffi-
cult and expensive specific locus test in inbred mice is also
satisfactory.
For assessing risk to man on the mutagenicity of endo-
sulfan, data that are necessary also includes the demonstra-
tion that the proposed mutagenic metabolite actually can
C-63
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reach the germ cells of mammals when the compound is dosed.
Further, knowledge of the comparative metabolism of endosul-
fan in the test species versus that of man is needed.
No tests have been run which define mammalian suppres-
sion of DNA repair, disturbed segregation of chromosomes, or
outright production of gene mutations or chromosomal aberra-
tions.
Studies have been conducted that include Ames tests on
endosulfan isomers and proposed metabolites using four common
Salmonella typhimurium strains and liver homogenate S-9 frac-
tion. No mutagenicity was seen in defined systems, although
three of five metabolites were toxic to the bacteria.
Carcinogenicity
Two bioassay tests by the NCI have been run on endosul-
fan. In the first test (Kotin, et al. 1968; Innes, et al.
1969) a 96 percent pure mixture of the isomers of endosulfan
was administered to mice by two routes: either as an injec-
tion in dimethylsulfoxide (DMSO) on the 28th day of age (2.15
mg/kg, subcutaneously) or by stomach tube orally on days 7 to
28 (2.15 mg/kg in gelatin) following which the compound was
mixed with ground feed at levels of 3 and 6 mg/kg feed.
The mice, C57B1/6 and C3H/AnfFl strains of both sexes,
showed incidences of tumors during the nearly 18 months of
feeding as tabulated (see Figure 2). Innes, et al. (1969)
summarized the statistical analyses and concluded there was
no evidence of endosulfan carcinogenicity.
In the second NCI bioassay on endosulfan, technical
grade endosulfan of 98.8 percent purity was dissolved in corn
C-64
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oil and mixed with the feed for 50 Osborne-Mendel rats of
each sex and 50 B6C3F1 mice of each sex. Chemical admini-
stration was for 78 weeks after which rats were observed for
33 additional weeks and mice for 14 additional weeks. The
trials on male rats were terminated early, week 82 for high
dose and week 74 for low dose. Time-weighted average concen-
trations of endosulfan in the diets for the entire study are
tabulated below.
Osborne-Mendel Rats B6C3F1 Mice
Male (mg/kg) Female (mg/kg) Male (mg/kg) Female (mg/kg
High dose 952 445 High dose 6.9 3.9
Low dose 408 223 Low dose 3.5 2.0
C-65
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Gastric
Papilloma
,_ ^ Hepatoma
0 CO
_c
o «
^ •- Pulmonary
i. a) D Adenoma
S iJ°°
Other
Tumors
_ 40"
10 ^\
— 12 Cf
/"^ /^^
2.9 O 24.0CJ
2.9O 9.5Q
xV1 /-V1
2.9 Q • 8 CJ
2.9Q 19 O
14. 3 (J
14.3 Cf
i
036
Concentration Endosulfan in Feed, mg/Kg Feed
Figure 2. Tabulation of mouse tumor data from NCI bioassay
on endosulfan (Kotin, et al. 1968)
-------
The doses of endosulfan used in these studies were toxic
to the kidney of rats of both sexes and to male mice. Male
rats also had testicular atrophy, and high early death rates
occurred in both species of male mice. Due to these early
deaths, the bioassay was not conclusive with regard to males,
but enough females survived to conclude that technical grade
endosulfan is not a carcinogen to female B6C3F1 mice or to
female Osborne-Mendel rats.
The official NCI summary recommended against retest of
endosulfan based on the early male animal mortality, since in
the female test animals, the chemical was noncarcinogenic.
Interesting relationships that were not discussed in the
official summaries appear when the data are examined closely.
Table 11, which presents tumors by site and ignores the early
deaths, shows that there were move liver and lung tumors in
the male mice than in matched controls, but this increased
occurrence of tumors is not dose-dependent: there were 6/49
liver tumors in the low dose males but only 2/50 in the high
dose, and 1/20 in the matched controls. Again, in the occur-
rence of alveolar/bronchiolar carcinoma, the matched controls
had 0/20, but both high and low dose male mice had two in
populations of 50 and 49, respectively.
Early mortality occurred in the males of both rats and
mice, but was a particular problem in the rats. A general-
ized toxic nephropathy probably contributed most significant-
ly to the early deaths, but signs commonly associated with
aging in group-housed laboratory rats were reported in equal
numbers in both dosed and control animals during the last 6
C-67
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months. The table below summarizes the early mortality. In
necropsies of the early deaths, several lesions were found,
but no actual dose-response pattern was evident, so no cause
was ascribed by the authors to the early animal deaths. The
most prevalent lesions include: nephropathy, parathyroid hy-
perplasia, and testicular atrophy in male rats. Cannibalism
was the most common cause of early death in male mice.
ANIMAL SURVIVAL TIMES: TUMOR BIOASSAY STUDIES
Dose level % living at study end
Species Sex or control (110 wk=rats 90 wk=mice)
Rat Male High
Low
Control
Female High
Low
Control
Mice Male High
Low
Control
Female High
Low
Control
o
-------
TABLE 11
i ncid© nee
Target Organs for Endosulfan-Induced Tumors POp latio
n
i
VO
Osborne-Mendel High dose3/
rats Male Low dose*3/
Controls
High dosec/
Female Low dosed/
Controls
High dosefy
Male Low dose*/
Controls
B6C3F1 mice High dose9/
Female Low dosen/
Controls
Lung
0/47
0/50
1/20
1/50
1/50
0/20
2/50
2/49
0/20
0/50
6/50
2/20
Lymphomas/
Leukemias
1/47
2/50
4/20
1/50
3/50
1/20
0/50
0/49
0/20
6/50
10/50
6/20
Kidney
2/47
3/50
2/20
3/50
2/50
1/20
0/50
0/49
0/20
0/50
0/50
0/20
Liver
0/47
0/50
0/20
1/50
1/50
0/20
2/50
6/49
1/20
1/50
0/50
0/20
Endocrine
0/47
1/50
7/20
11/50
19/50
13/20
0/50
0/45
0/20
1/50
0/50
0/20
All other sit«
0/47
4/50
0/20
15/50
27/50
14/20-
6/50
1/49
3/20
3/50
4/50
1/20
Summarized from NCI Bioassay Data (Weisburger, et al. 1978)
f/ 952 mg/kg feed
b/ 408 mg/kg feed
^/ 445 mg/kg feed
d/ 223 mg/kg feed
6.9 mg/kg feed
3.5 mg/kg feed
3.9 mg/kg feed
2.0 mg/kg feed
-------
The 95 percent confidence intervals on the relative risk
of developing a tumor furnish additional insight into the
statistical implications of these data. Many of the confi-
dence intervals, due to the early mortality, have an upper
limit greater than one, indicating the theoretical possibil-
ity that the test did not conclusively address the possibil-
ity of tumor induction by endosulfan. In all cases except
one, however, the relative risk is unrelated to the dose of
endosulfan received. The occurrence of fibrosarcoma of sub-
cutaneous tissue in male mice showed a relative risk greater
than one when compared to both pooled controls and with
matched controls, and the risk was dose-related (Table 11,
NCI Bioassay, Weisburger, et al. 1978). The high incidence
of fibrosarcoma of subcutaneous tissue in all control male
mice suggests this difference is unimportant to the overall
carcinogenicity of endosulfan.
Figure 3 illustrates time to tumor data for rats and
mice for this study.
C-70
-------
n
i
MICE
RATS
Hi Dose
Lo Dose
Controls
Hi Dose
Lo Dose
Controls
**-
9
9
cf
cf
cf
1 1
cf
9
cf
9
•
1
cf
9
•
9
i
0
25 50 75
Time to 1st Tumor, Weeks
100
Figure 3. Scattergram of time to tumor, rat/mouse endosulfan bioassay.
Source: Tabulated from NCI bioassay data (Weisburger, et al. 1978).
-------
The significance of the negative carcinogenicity data in
the latest NCI bioassay is increased by several factors in-
volved in the choice of model, which was a stringent test for
carcinogenicity.
The C3H strain of mouse has one of the highest known
incidences of mammary tumors in females and liver tumors in
males, and was a parent strain in both the carcinogenesis bio-
assay of 1968 and of 1978. Differences in species responses
to chemical carcinogens can often be attributed to differing
metabolic pathways and metabolites, and to an inability of
some species to effectively convert the test chemical to an
active carcinogen. The work of Gupta (1978) and Gupta and
Chandra (1975) has indicated, however, that rats, mice, and
rabbits all metabolize endosulfan. The mouse strain used by
the NCI in the 1978 carcinogenesis bioassay of endosulfan is
so prone to the development of liver tumors with minimal
stimulation, that two working conferences on the use of such
mice to assess carcinogenicity have been held; in 1969 (IARC,
1971) and 1975 (Butler and Newberne, 1975). Neither confer-
ence has been able to state conclusively which mouse data
should be applied to risk assessment. When very high levels
of test compound (such as those used for both bioassay trials
of endosulfan) are used, tissue injury and repair may be im-
portant in the development of lesions. Other factors such as
sex, hormones, and diet have been suggested as possible modi-
fiers of the carcinogenic activities of primary carcinogens.
The distinct differences in toxicity to males versus females
seen in many endosulfan tests makes it quite likely that hor-
C-72
-------
monal differences influenced the. final test result in the
carcinogenicity bioassays.
The Osborne-Mendel rat, also used in the NCI bioassay of
endosulfan (Weisburger, et al. 1978), is known to be a strain
very resistant to toxicity, so that high dose levels for ex-
tended periods can be administered. This increases the like-
lihood for survival and the appearance of any tumors that
would be misse'd in trials with early deaths (Tomatis, et al.
1973). The fact that toxicity and early deaths occurred in
the male Osborne-Mendel rats in the 1978 endosulfan bioassays
is another indication that doses were more than adequate to
produce an effect if the chance existed to produce one.
These animal models give an additionally severe test of
carcinogenicity in that the parent mice of these inbred
strains carry tumor viruses. In the 1968 NCI bioassay, for
example, the AKR strain has a high rate of leukemia by six to
eight months of age. Use of the C3H strain, with the murine
mammary virus, and the AKR strains of mice means these bio-
assays are also testing for promotion mechanisms of the test
chemical. There are no known human tumors that occur by pro-
motion of a human tumor virus, so the use of these strains to
test for carcinogenicity is a severe trial. In addition,
Henschler (1977) has suggested that mice in general have a
particularly low activity of epoxide hydrase, i.e., mice have
a decreased ability compared to other animals to detoxify
reactive epoxides, which are the reactive and toxic interme-
diates formed in vivo as metabolites in many industrial chem-
icals.
C-73
-------
Route of exposure, used in the NCI trials (high dietary
levels), is less relevant to human exposure (dermal and in-
halation of particulates) than it is to domestic animals.
While these bioassay trials did not measure gastrointestinal
absorption, it is likely that a high concentration of endo-
sulfan reached the liver by the portal circulation with each
meal taken by the test rodents. Endosulfan that reaches the
liver complexing and detoxification mechanisms by dermal or
inhalation routes do so after passage through tissue, the
blood stream, and contact with many cellular mechanisms. The
oral route is a particularly severe test for liver effects,
and the lack of such effects in these trials is further
indication of a clean bill of health for the carcinogenicity
of endosulfan. It is also worthy of note that absorption
from the gastrointestinal tract is the route that is most
likely to ensure that metabolites of endosulfan as well as
the alpha and beta isomers impinge upon not only the liver
but also other organs and tissues of the body.
Ely, et al. (1967) reported that one or more convulsions
occurred in each of nine workers exposed to a 50 percent en-
dosulfan wettable powder. Six of the nine cases were known
not to have had a history of previous convulsions, but the
previous history of the other three was uncertain. A causal
relationship between convulsions and exposure to endosulfan
was, however, considered highly likely.
The potential vulnerability of the central nervous sys-
tems of humans to endosulfan was demonstrated in epileptic
convulsions and altered EEC patterns in three subjects ex-
C-74
-------
posed to the pesticide. In one of the patients, occasional
EEC alterations were observed one year after the exposure
(Tiberin, et al. 1970).
Five human deaths due to endosulfan were reported by
Terziev, et al. (1974), two of which were accidental poison-
ings and three of which were the result of intentional in-
take. Details were lacking, but the most significant post-
mortem findings as described by Terziev were circulatory dis-
orders, protein dystrophy in the parenchymal organs, acute
lung emphysema, and severe changes in the neurons.
Two poisoning cases resulting in human fatalities were
reported with 20 percent endosulfan products, and both in-
volved interaction with other chemicals (alcohol in one case
and alcohol with dimethoate in the second). Demeter and
Heyndrickx (1978) found ^»- and ^-endosulfan in the different
tissues of the victims as follows:
Organ/Tissue Endosulfan Levels
Small intestine 314 and 289
Blood Below 6.1 and 0.075 mg/1
Brain 4.1 mg/kg and unreported
Kidney 11.4 and 4.28 mg/kg
Urine Below 0.1 and 2.65 mg/1
Alcohol was present in the blood and urine of both poisoning
fatalities at a level of 2.34 and 1.81 mg/1 for blood and
3.46 and 2.47 mg/1 for urine. One of the men was extremely
nauseous when found, and died shortly afterward. The other
was found dead, with an extremely cyanotic appearance. No
other symptoms of toxicity were reported.
The intentional ingestion of unknown quantities of a 35
percent emulsifiable concentrate formulation of endosulfan
C-75
-------
resulted in three human fatalities. Coutselinis, et al.
(1978) analyzed blood and viscera and reported that the
average concentration levels of both isomers of endosulfan
were 0.63 mg/ 100 ml blood; 0.11 mg/100 g liver tissue; 0.28
mg/100 g kidney tissue; and 0.028/100 g brain.
Seven European countries that have heavy use of endosul-
fan were queried for user reports of toxicity or allergic
manifestations in normal usage. No symptoms that might be
connected with the normal application of endosulfan have
become known with regard to humans (Hoechst, 1966).
Israeli, et al. (1969) report three cases of endosulfan
toxicity in workers in a chemical factory. Poisoning occur-
red as they filled bags with the insecticide, neglecting pro-
tective clothing and masks. The symptoms appeared rapidly,
within one to two hours in the lethal cases, and included
initially headache, restlessness, and increased irritability,
followed by vertigo, stupor, disorientation, and epileptiform
convulsive seizures. In the workers that died, there was
also loss of consciousness, cyanosis, dyspnea, foaming at the
mouth, and noisy breathing (Israeli, et al. 1969). It was
noted in a later report (Tiberin, et al. 1970) that there
were pathological changes on the electroencephalograms.
Hyperventilation improved the EEC picture.
C-76
-------
CRITERION FORMULATION
Existing Guidelines and Standards
The National Technical Advisory Committee on Water Qual-
ity Criteria (USDI, 1968) did not establish a permissible
limit of endosulfan in raw surface waters for public water
supply purposes. The Committee stated, however, that the 48-
hour TI^ (median, tolerance level) of endosulfan to shrimp
is 0.2 ug/1 and therefore classified endosulfan as acutely
toxic to shrimp at concentrations of 5 ug/1 or less. On the
assumption that 1/100 of this level represents a reasonable
application factor, the Committee recommended that environ-
mental levels of endosulfan should not be permitted to rise
above 0.05 ug/1. This level is so low that endosulfan should
not be applied directly in or near the marine habitat without
danger of causing damage.
In the 1972 report of the Committee on Water Quality
Criteria (National Academy of Sciences/National Academy of
Engineering, 1972), a maximum concentration of 0.003 ug/1 of
endosulfan is recommended for whole (unfiltered) fresh water
sampled at any time and at any place. This concentration was
determined by multiplying the acute toxicity value of endo-
sulfan for the most sensitive native aquatic species (rainbow
trout, Salmo gairdneri) (Schoettger, 1970) by an application
factor of 0.01. The marine criterion of 0.001 ug/1 was simi-
larly determined using LCso values of the most sensitive
marine species (striped bass, Morone saxatilis (Korn and)
Earnest, 1974).
C-77
-------
Revision of the above recommended standards may be indi-
cated by more recent data. For example, the 96-hour LC5Q
value of 0.04 ug/1 on pink shrimp (Penaeus duorarum) would,
if incorporated, reduce the saltwater criterion from 0.001
ug/1 to 0.0004 ug/lf using a theoretical application factor
of 0.01 (Schimmel, et al. 1977). This theoretical ratio is
used in the absence of an empirically derived factor. Macek,
et al. (1976) have empirically derived application factors
from their work on two fresh water species, fathead minnows
(Pimephales promelas) and water fleas (Daphnia magna). The
seven-day incipient LCsg of 0.86 ug/1 and the maximum accept-
able toxicant concentration (MATC) limits of 0.20 to 0.40
ug/1 for fathead minnows give a derived application factor
(ratio of chronic toxicity to acute or subactue) range of
0.23 to 0.47. MATC limits are the highest concentration for
which there is no effect and the lowest concentration showing
an adverse effect. The 48- hour LC5Q of 166 ug/1 and the
MATC limits of 2.7 to 7.0 ug/1 for Daphnia magna, however,
give a derived factor range of 0.016 to 0.042.
The recent National Academy of Sciences report on drink-
ing water did not address water standards for endosulfan
(NAS, 1977).
Current Level of Exposure
Endosulfan has been detected in water samples from the
United States and Canada. Maximum values reported from
various studies include:
C-78
-------
0.02 ug/1 in streams of the-western United States (one
positive sample out of 546).
0.032 ug/1 in drainage ditches from treated agricultural
fields near Lake Erie.
0.011 ug/1 in Canadian water systems.
0.883 ug/1 in Ontario municipal water samples.
0.014 ug/1 in surface and bottom water samples from Lake
Erie.
The detection limit for endosulfan in water, using elec-
troncapture gas chromatographic methods, is /^ 0.005 ug/1
(Schulze, et al. 1973) .
0.060 ug/1 in the St. Lawrence River.
Residues in food (^-endosulfan, /0-endosulfan, and endo-
sulfan sulfate) result from the use of endosulfan on over 60
food and nonfood crops.
During the 1965 to 1970 period, daily U.S. intake of en-
dosulfan residues was estimated using market basket samples
from the total diet program of the FDA. These samples showed
a daily intake of endosulfan (^-, &-, and sulfate) of from
<0.001 to 0.001 mg/day.
The acceptable daily intake of endosulfan (i.e., the
daily intake which during an entire lifetime appears to be
without appreciable risk), as established by FAO/WHO, is
0.0075 mg/kg. This value corresponds to an intake of 0.525
mg/day for a 70-kg person.
Endosulfan has also been shown to bioconcentrate in the
tissue of aquatic species. Bioconcentration data are summa-
rized in Table 12.
C-79
-------
TABLE 12
Summary of Bioconcentration Data for Endosulfan
Test species
Common mussel
(Mutilus edulis)
Scallop
(Ghlamys opercularis)
o Pink shrimp
as (Penacus duorarum)
o
Grass shrimp
(Palaemonetes vulgaris)
Mullet
(Mugil cephalus)
Spot
(Leiostomus xanthurus)
Pinfish
(Lagodon rhomboides)
Goldfish
(Garassius auratus)
Measured
water concentration
(mg/liter)
1,000
100
0.14^7
100
0.089
1.75
0.32
0.035
0.076
0.15
1
Exposure
period
(days)
70
14
14
4
4
4
28
4
4
5
Bioconcentration
factorf/
22.5
28. 5f/
600
25.757
0
245
1,344
2,755
(2,429)£/
895
1,299
400
Source
Roberts (1972)
Roberts (1975)
Ernst (1977)
Roberts (1975)
Schimmel, et al. (19"
Schimmel, et al. (19",
Schimmel, et al. (19"
Schimmel, et al. (19*
Schimmel, et al. (19'
Schimmel, et al. (19*
Gorbach (1972)
Highest bioconcentration factor reported by the respective investigators. Whole body basis
unless otherwise noted.
-Endosulfan steady-state concentration; initial concentreation was 2.05 ug/liter.
c/ Based on summated values for separate tissues.
Edible tissue.
-------
Endosulfan residues (^-endosulfan, ^-endosulfan, and
endosulfan sulfate) have been detected in most types of U.S.
tobacco products in recent years. The following data summa-
rize the average residue levels (milligram residue per kilo-
gram processed tobacco) detected in several independent
studies.
Cigarettes
Cigars
Little cigars
Smoking tobacco
or pipe tobacco
Chewing tobacco
Snuff
Average residue
Year (mg/kg)
1971 0.2
1972 0.38
1973 0.83
1971 0.4
1972 0.41
1973 0.37
1971 0.4
1973 0.22
1971 <0.2
1973 0.37
1971 0.2
1973 0.36
1971 <0.2
1973 <0.12
Source
Domanski, et al. (1973)
Dorough and Gibson (1972)
Domanski, et al. (1974)
Domanski, et al. (1973)
Domanski and Guthrie (1974)
Domanski, et al. (1974)
Domanski, et al. (1973)
Domanski, et al. (1974)
Domanski, et al. (1973)
Domanski, et al. (1974)
Domanski, et al. (1973)
Domanski, et al. (1974)
Domanski, et al. (1973)
Domanski, et al. (1974)
Air samples from 16 states in 1970 showed an average
level of 13.0 ng/m^^-endosulfan and 0.2 ng/m3 ^-endosulfan.
None of the air samples collected in 1971 or 1972, however,
contained detectable levels of either isomer.
Special Groups at Risk
Data on the presence of endosulfan residues (^-endosul-
fan, ^-endosulfan, and endosulfan sulfate) in food, tobacco,
water, and air have been briefly summarized in the preceding
subsection. These data indicate the following three human
populations that are at risk of exposure to endosulfan:
C-81
-------
(1) Exposures occur primarily from: residues in foods
as a result of the use of endosulfan on food crops and
feedstuff; bioconcentration in aquatic species; residues in
air adjacent to sites of manufacture or application; and
residues in water.
(2) Residues in processed tobacco products (cigarettes,
cigars, snuff, etc.) result from the field use of endo-
sulfan.
(3) Dermal and respiratory exposure can occur during
manufacture, formulation/packaging, field application, and
harvesting.
Basis and Derivation of Criterion
Establishing a scientific basis for evaluating the haz-
ard of endosulfan to man is difficult. At very high levels
of acute exposure, humans show central nervous system (CNS)
symptoms and may die. Several studies report endosulfan has
been used for suicides (Terziev, et al. 1974; Couteslinis, et
al. 1978). Workers who failed to use good safety practices
(i.e., to cover skin and use respiratory protection) have
died from endosulfan exposure (Israeli, et al. 1969). In one
incident, three persons exposed showed CNS symptoms; two of
them died. It therefore appears that the most toxic poten-
tial effect to man is that of CNS toxicity since the avail-
able data indicate a lack of carcinogenic, mutagenic, or
teratogenic potential. The absence of reports on toxic
effects associated with the proper use of endosulfan (partic-
ularly such effects as skin sensitization or other human
symptoms) has been noted (Hoechst, 1966).
C-82
-------
There appears to be considerable species variation in
toxic effects. Of the species tested with endosulfan, cattle
are the most sensitive to the neurotoxic effects and would
therefore be a "worst case" model for human toxicity. There
are much more controlled toxicity data on rodents, but cattle
appear to be closer in sensitivity and effects to man. Data
on CNS toxicity to cattle are presented in Table 13.
The relevance of these high exposure levels to a water
quality standard presents additional sources of calculation
error. The CNS toxicity in these studies is an acute symptom
of high exposure. All reported human poisonings, however,
have resulted from accident, human error, or suicidal inten-
tion. The reported poisonings of man and the most sensitive
other mammal, cattle, have occurred after acute, high level
exposure to concentrated endosulfan. These levels will not
occur in drinking water. The key question then is, are there
any data in the toxicology reports or studies to indicate
that CNS effects can occur after chronic, very low level
exposure to endosulfan?
Tiberin, et al. (1970) reported occasional EEC altera-
tion in one of three men one year after a convulsive seizure
following exposure to endosulfan. Terziev, et al. (1974) re-
port that autopsy on an endosulfan suicide case showed
"changes in the neurons" among lesions in other organs.
Rats, although more resistant to toxicity than man or cattle,
demonstrate no histopathological changes in the brain after
receiving high doses of endosulfan orally for 78 weeks, or
most of a lifetime (Weisburger, et al. 1978).
C-83
-------
TABLE 13
Lethality and CNS Toxicity of Endosulfan in Cattle
0
1
00
.t*.
Dose, route
12.5 mg/kg , oral
0.12% formulation,
dermal
4% dust, dermal
35% powder, dermal
Number
animals
exposed
2
250
5
30
% Exposed
Time to CNS showing
toxicity (hours) CNS effects
10 100
5 20
2 100
5 Apparently
100%
Time to death
(days)
6
1
1
Hours to days
% Exposed
dying
50
4
80
50
Source
Li, et al. (1970)
Thompson (1966)
Nicholson and
Cooper (1977)
Braun and Lobb
(1976)
-------
Cerebral hemorrhage was reported in seven female rats
that died early in the study (week 21) but the absence of
lesions at even higher and more long-term dosage suggested to
the authors that these deaths were not compound-related.
Several lesions were present in the male rats and mice that
died early in these endosulfan feeding studies. The most
prevalent lesions included nephropathy, parathyroid hyper-
plasia and testicular atrophy, all without clear dose re-
sponse pattern (Weisburger, et al. 1978).
An important question is "Do the apolar metabolites of
endosulfan remain in the body to produce chronic effects if
endosulfan is ingested in low level quantities over a long
term?" No controlled metabolic studies in man have been
reported, although Demeter and Heyndrickx (1978) report that
endosulfan sulfate is a metabolite in humans. This metabo-
lite is approximately as toxic to mice as the parent isomers
(Dorough, et al. 1978), but no specific CNS effects were
reported (based on toxicity trials on the pure compound).
The toxicity of endosulfan is somewhat greater in ani-
mals with deficiencies of dietary protein (Boyd and Dobos,
1969; Boyd, et al. 1970). The differences in even a dose as
high as an LD5Q are not great enough, however, to ascribe any
potential human hazard to this mechanism or to suggest that
protein-deprived humans would be more sensitive to chronic
exposure to endosulfan in drinking water.
It can be concluded that (a) the controlled studies uni-
formly report CNS toxicity following acute high level expo-
sure and (b) there has been no indication reported of specific
C-85
-------
lesions in mammals related to mortality following chronic
exposure.
A water quality criterion could be based on the lowest
no-effect level (NOEL) reported for endosulfan in test
species. Available data on no-effect levels are summarized
in Table 14.
The lowest NOEL reported in the published literature is
2.0 mg endosulfan per kilogram feed when fed to mice for 78
weeks (Weisburger, et al. 1978). This dose corresponds to
0.4 mg endosulfan/kilogram body weight per day for a typical
25 gram mouse consuming 5 grams feed/day:
/2.0 mg endosulfanl (5 g feed^ /mouse \ n , „„/,„„/,,,,
I 1,000 g feed ,/ Uouse-dayj (o.025 Kg) = °'4 m9A9/da
Applying a 0.01 animal to human uncertainty factor to this
dosage gives an upper limit for nonoccupational daily
exposure (ADI) of 0.28 rag/Kg body weight for a 70 Kg person:
(0'01) - "•» -/-y
For the purpose of establishing a water quality crite-
rion, human exposure to endosulfan is considered to be based
on ingestion of 2 1 of water and 18.7 g of fish/day. The
amount of water ingested is approximately 100 times greater
than the amount of fish consumed. The fish bioaccumulation
factor for endosulfan, has been established to be 28.
C-86
-------
The equation for calculating the criterion for
endosulfan content of water is:
(2) (X) + (0.0187) (F) (X) = ADI
where: 2 = amount of drinking water was consumed, I/day
X = endosulfan concentration in water, mg/1
0.0187 = amount of fish consumed, Kg/day
F = bioaccumulation factor, mg endosulfan/Kg fish
per mg endosulfan/1 water
ADI = limit on daily exposure for a 70 Kg person
For F = 28
2X + (0.0187) (28) (X) = 0.28
2.52X = 0.28
X = 0.11 mg/1 or -w 0.1 mg/1
Consideration of dietary endosulfan levels (apparently 0.01
mg/day or less) and other sources of exposure (ambient
levels, cigarette smoke, etc.) does not significantly affect
this calculation. —N
In summary, based on the use of chronic toxicologic test
data for mice and an uncertainty factor of 100, the criterion
level for endosulfan is 0.1 mg/1. Drinking water contributes
79 percent of the assumed exposure while eating contaminated
fish products accounts for 21 percent. The criterion level
can alternatively be expressed as 0.5 mg/1 if exposure is
assumed to be from the consumption of fish and shellfish
products alone.
C-87
-------
TABLE 14
No-Effect Dose Levels for Endosulfan on Different Species and Biochemical Parameters
Species
Rats
Rat
Rat
Rat
Rat
Rat (female
n Osborne-Mendel)
^ Hamsters
00
Hamsters
Mice
Mice
(Female B6C3F1)
Rabbit
Rabbit
Rabbit
Chickens
Dog
Salmonella
typhimurium
Organ/Tissue
_
-
Liver
Liver
Embryo
-
-
Liver
-
-
Eye
Eye
Skin
Egg
Strains TA98,
100, 1534,
and 1978
Effect Observed
Lethality
Lethality
D
Cholinesterase
inhibition
Microsome enzyme
function
Teratogenicity
Lethality
Lethality
Enzyme inhibition:
GPT, LDH
Weight depression
Lethality
Inflammation and
irritation
Inflammation, .
irritation
Irritation
Hatchability
Gross and microscopic
lesions
Base-pair substitution
(mutagenicity )
No-effect dose
~" 55 mg/kg = LD0
40 mg/kg = LDg
68 mg/kg minimum
50 ppm diet
10 mg/kg
445 ppm diet
70 mg/kg
134 mg/kg minimum
3.2 ppm diet
2.0 ppm diet
1:1,000 aqueous
20% aqueous solution
100 mg/kg
0.07 mg/egg
0.75 mgAg/day
1.0 mg/plate
Route administered;3/
Acute Oral
( Intragastric)
Acute Oral
Acute Oral
Diet
(2 weeks)
Oral
(Gestation Day 7-14)
Diet
(78 weeks)
Acute Oral
Acute Oral
Diet
(6 weeks)
Diet
(78 weeks) «
Instillation
Instillation
Dermal
Yolk injection
Oral
(52 weeks)
-
Source
Boyd and Dobos
(1969)
Truhaut, et al .
(1974)
Truhaut, et al .
(1974)
Den Tonkelaar and
Van Esch (1974)
Gupta, et al.
(1978)
Weisburger, et al.
(1978)
Truhaut, et al .
(1974)
Truhaut, et al .
(1974)
Weisburger, et al.
(1978)
Weisburger, et al .
(1978)
Hoechst (1967a)
Gupta and Chandra
(1975)
Gupta and Chandra
(1975)
Smith, et al. (1970)
FMC (1967)
Dorough, et al.
(1978)
Single dose unless otherwise noted
-------
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