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-
                             A-l

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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,
                              A-2

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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.
                             A-3

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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.
                              A-4

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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.
                             A-5

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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.
                             B-l

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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
                              B-2

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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-
                              B-4

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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
                              B-6

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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.
                              B-8

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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.
                             B-9

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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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03
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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03
 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

-------
                       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
                             B-17                                  2 ''

-------
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

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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

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     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

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      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

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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

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     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

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                                                   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

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                                  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

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     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

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                                  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

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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

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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

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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

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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

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     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).
                               C-43

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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

-------
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).
                              C-61

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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

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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

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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

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     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

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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

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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

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                    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

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     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

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                                               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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