SUBSTITUTE CHEMICAL PROGRAM
         INITIAL SCIENTIFIC
    MINIECONOMIC REVIEW
                  PARATHION
                    JANUARY 1975
         U.S. ENVIRONMENTAL PROTECTION AGENCY
              OFFICE OF PESTICIDE PROGRAMS
         rttos^JCRITERIA AND EVALUATION DIVISION
          — **.      WASHINGTON, D.C. 20480
                       EPA-540/1-75-001

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This report has been compiled by the Criteria and
Evaluation Division, Office of Pesticide Programs,
EPA, in conjunction with other sources listed in
the Preface.  Its contents do not necessarily
reflect the views and policies of the Environ-
mental Protection Agency, nor does mention of
trade names or commercial products constitute
endorsement or recommendation for use.

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                          GENERAL CONTENTS

                                                                          Page

List of Figures	vi


List of Tables	vii


Preface	xi



Part    I.         Summary	1


Part   II.         Initial Scientific Review	12
      Subpart A.      Chemistry 	   12
      Subpart B.      Pharmacology and Toxicology 	   55
      Subpart C.      Fate and Significance in the Environment	139
      Subpart D.      Production and Use	212
Part  III.         Minieconomic Review	252

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                                   FIGURES

No.

1      Production Schematic for Parathion 	 18


2      Major Photodegradation Products of Parathion 	 24
       Analytical Scheme for Chlorinated  (Nonionic) and Organophosphate
          Residues	25
       Major Photodegredation Products of Parathion 	 36
                                     vi

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                           TABLES
 No.                                                          Page
 1     Raw Materials and By-Products in the Manufacture
         of Parathion	   17
 2     Suggested Formulations for Parathion Emulsifiable
         Concentrates	   33
       Other Photodegradation Products of Parathion	   37
 4     Dietary Intake of Parathion and Total Organo-
         phosphates	   42
 5     Average Incident and Daily Intake of Parathion. ...   43
 6     Percent Distribution of Parathion Residues by Fiscal
         Tear in Different Quantitative Ranges 	   45
 7     Summary of U.S.  Tolerances for Parathion and/or
         Methyl Parathion on Raw Agricultural Commodities. .   48
 8     Acute Oral Toxicity of Parathion for Rats	   58
 9     Acute Toxicity of Parathion for Rats Via Routes
         Other Than Oral	   59
10     Chronic Oral Toxicity Test in Rats Fed Parathion. . .   62


11     Acute Oral Toxicity of Parathion to Mice	   64


                            vii

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                      TABLES (Continued)
No.
12     Acute Toxicity of Parathion to Mice—Routes Other
         Than Oral	66
13     Acute Oral Toxicity of Parathion to Guinea Pigs ...  67
14     The Toxic and Teratogenic Effect of Parathion
         Given Intraperitoneally to Rats on the llth
         Day of Pregnancy	89
15     Percentage of Chromosomal Changes at Metaphase of
         Male Guinea Pigs After Parathion (0.05 tng/testical)
         Treatment	99
16     Susceptibility of Man and Other Animals to Single
         Oral Dosts of Parathion	101
17     The Susceptibility of Man and Other Animals to
         Repeated Oral Doses of Parathion	102
18     Acute Toxicity of Parathion to Fish	142
19     Common and Scientific Names of Fish Used in Controlled
         Toxicity Tests With Parathion  	 143
20     Comparative Toxicity of Parathion and Malathion
         Insecticides to Centrarchids	143
21     Toxicity of Three Organophosphate Insecticides
         to Bluegill and White Rats	144
22     E^5Q  (immobilization) Values (ppb) of Three Organo-
         phosphate Insecticides to Zooplankton 	 152
23     LC50 Values  (ppb) of Three Organophosphate Insecti-
         cides to Benthic Invertebrates	153


24     Acute Toxicity of Parathion to Avian Species	158
                             viii

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No.                                                            Page

25     Common and Scientific Names of Birds Used in Con-
         trolled Toxicity Tests With Parathion 	    158
26     Avian Oral Toxicity (5 days)	    159


27     Effect of Age on Parathion Toxicity in Mallard Ducks.    160
28     Effects of Intravenous Injections of Parathion on
         Hematocrit of Ducks and Quail	    161
29     Parathion - Summary of Registered Uses by Crops,
         Application Rates, and Rate and Time Restrictions .     214
30     Pest Insects and Mites Against Which Parathion is
         Recommended (in alphabetical order by common
         names)	   219
31     Registered Uses of Parathion Emulsifiable Liquid
         (4 Ib active ingredient per gallon) - Crops and
         Other Uses, Pests, Dosage Rates and Use
         Limitations	    222
32     Registered Uses of Parathion Emulsifiable Liquid
         (4 Ib active ingredient per gallon)  - Crops and
         Other Uses, Pests, Dosage Rates and  Use
         Limitations	    231
33     Estimated Uses of Parathion on the U.S.  by Regions
         and Major Crops (1972)	     243
34     Parathion Uses in California by Major Crops and
         Other Uses (1970-1973)	     246
35     Use of Parathion in California in 1972, by Crops,
         Applications, Quantities, and Acres Treated ....    247
36     Use of Parathion in California in 1973, by Crops,
         Applications, Quantities, and Acres Treated ....    249
                             ix

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No^                                                              Page

37     Results of Parathion Application on Sorghum
         Midge	    259
       Results of Parathion Application on Sorghum
         Greenbug	     261
39     Results of Parathion Application on Wheat
         Greenbug .	     263
 -iO     Results of Parathion Application on Corn Insect
         Pests .	      264
41     Results of Parathion Application for Wireworm
         Control	      265
42     Results of Parathion Application on Strawberry
         Tarnished Plant Bug	      267

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                                 PREFACE
     The Alternative (Substitute) Chemicals Program was initiated under
Public Law 93-135 of October 24, 1973, to "provide research and testing
of substitute chemicals."  The legislative intent is to prevent using
substitutes, which in essence are more deleterious to man and his environ-
ment, than a problem pesticide (one that has been suspended, cancelled,
deregistered or in an "internal review" for suspected "unreasonable
adverse effects to man or his environment").  The major objective of the
program is to determine the suitability of substitute chemicals which
now or in the future may act as replacements for those uses (major and
minor) of pesticides that have been cancelled, suspended, or are in litiga-
tion or under internal review for potential unreasonable adverse effects
on man and his environment.

     The substitute chemical is reviewed for suitability considering all
applicable scientific factors such as:  chemistry, toxicology, pharma-
cology and environmental fate and movement; and socio-economic factors
such as:  use patterns and costs and benefits.  EPA recognizes the fact
that even though a compound is registered it still may not be a practical
substitute for a particular use or uses of a problem pesticide.  The
utilitarian value of the "substitute" must be evaluated by reviewing its
biological and economic data.  The reviews of substitute chemicals are
carried out in two phases.  Phase I conducts these reviews based on data
bases readily accessible at the present time.  An Initial Scientific
Review and Mini-Economic Review are conducted simultaneously to determine
if there is enough data to make a judgment with respect to the "safety
and efficacy" of the substitute chemical.  Phase II is only performed if
the Phase I reviews identify certain questions of safety or lack of benefits
The Phase II reviews conduct in-depth studies of these questions of safety
and cost/benefits and consider both present and projected future uses of
the substitute chemicals.

     The report summarizes rather than interprets scientific data
reviewed during the course of the studies.   Data is not correlated from
different sources.   Opinions are not given on contradictory  findings.

     This report contains the Phase I Initial Scientific and Mini-Economic
Review of parathion (0,)-dimethyl 0-p-nitrophenyl phosphorothioate).
Parathion was identified as a registered substitute chemical for certain
cancelled and suspended uses of DDT.  Where applicable, the review also
identifies areas where technical data may be lacking so that appropriate
studies may be initiated to develop desirable information.

     The review covers all uses of parathion and is intended to be
adaptable to future needs.  Should parathion be identified as a substitute
for a problem pesticide other than DDT, the review can be updated and made
readily available for use.  The data contained in this report was not
intended to be complete in all areas.  The review was coordinated by a
                                    XI

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team of EPA scientists in the Criteria and Evaluation Division of the
Office of Pesticide Programs.  The responsibility of the team leader
was to provide guidance and direction and technically review information
retrieved during the.course of the study.  The following EPA scientists
were members of the review team:  George Bagley  (Chemistry), team leader;
Jeff Conopask (Economics); E. David Thomas (Registered Uses); Ralph C.
Wright (Registered Uses); William Burnam (Pharmacology and Toxicology);
Elsie Kelley (Pharmacology and Toxicology); Howard Kerby (Fate and
Significance in the Environment); Richard Tucker  (Fate and Significance
in the Environment).

     Data research, abstracting  and collection were primarily performed
by Midwest Research Institute, Kansas City, Missouri  (EPA Contract #68-01-
2448).  RvR Consultants, Shawnee Mission, Kansas, under a subcontract  to
Midwest Research, assisted in data collection.  Monsanto, a manufacturer
of parathion, made scientific recommendations and additions to this report.
The recommendations of the following National Environmental Research
Centers, EPA Office of Research  and Development have  also been incorporated:
Southeast Environmental Research Laboratory, Athens,  Georgia; Pesticide
and Toxic Substances Effects Laboratory, Research Triangle Park, North
Carolina.
                                     xii

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                            PART I.   SUMMARY



                                 CONTENTS



                                                                      Page


Production and Use	    2



                                                                        o
Pharmacology and Toxicology  	    J



Food Tolerances and Acceptable Intake 	   7



Environmental Effects 	   7



Specific Hazards of Use	   9



Limitations in Available Scientific Data 	   10



Efficacy and Cost Effectiveness	10

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      This section contains a summary of the "Initial Scientific  and
Minieconomic Review" conducted on parathion.
Production and Use

     Parathion (0,0-diethyl 0-£-nitrophenyl phosphorothioate) is manu-
factured by a synthesis processing involving three reactions:
PS
      25
       4C2H5OH
             S
             II
              C12
                                     S
                                     It
2(C2H50)2PSH
                 HC1
                                                                   (1)
                                                                   (2)
(C2H50)2PC1
                      Na
                               NaCl
                                                                   (3)
                                            Parathion
     The chemical properties of parathion are similar to those of its
methyl analog (methyl parathion).  Parathion is oxidized enzymatically
to paraoxon (0,0-diethyl 0-p_-nitrophenyl phosphate), a reaction inti-
mately associated with parathion1 s biological effects.  The oxidation
of parathion to paraoxon can also be effected by chemical action of
atmospheric oxygen; atmospheric oxidation is accelerated by ultraviolet
radiation.
     Hydrolysis  of parathion virtually destroys all insecticidal
activity.  Fifty percent hydrolysis of parathion is achieved in 2.7 hr
in aqueous solutions at pH 9 and 70°C; in 17 to 20 hr at pH 1 and 70°C;
and in 690 days at pH 1 to 5 and 20°C. Fifty percent hydrolysis of
paraoxon requires 9.2 days in aqueous solution at pH 10 and 25 °C.

     Parathion is commercially available in a large number of registered
formulations and in many physical forms, including emulsifiable con-
centrates, wettable powders, dusts, granules, and aerosol formulations
containing only parathion or parathion in combination with other active
ingredients.

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     Parathlon has a very broad spectrum of effectiveness against in
sects and mites.  Tolerances for parathion residues have been estab-
lished on about 100 raw agricultural commodities.

     The estimated domestic production of parathion in 1972 is 14
million pounds.  About 10 million pounds (as active ingredient) were
used in the United States in 1972.  A review of available data on farm
use of parathion for the period 1966 to 1972 indicates an upward trend
of 2%/year in the usage of parathion in agriculture.  Two of the previous
domestic producers of parathion, however, have discontinued production
of this insecticide since 1972.  There is no assessment possible on
the ability of industry to increase parathion supply.

     Essentially all domestic usage of this pesticide is agricultural.
Parathion is registered and recommended for use on a large number of
domestic crops, including fruit, nut, vegetable, and field crops.

     Domestic crops on which parathion was used in 1972, listed in de-
creasing order of the quantity used, are:  cotton, sorghum and small
grains; deciduous fruit and nut crops; vegetable crops; corn; citrus
fruits; tobacco; and numerous other crops, each of which account for
a relatively small portion of the total usage.

     The 1972 domestic use pattern, by geographical region and in
decreasing order of use, is estimated to be:  West South Central ('ncl/hom?
and Texas); Southwest (California, Arizona, Hawaii, New Mexico, and
Nevada); Southeast; West North Central; East South Central; Northwest;
and Northeast.  Slightly more than 10% of all parathion used in the U.S.
in 1972 was applied in California on almost 100 different crops.

Pharmacology and Toxicology

     Parathion is a highly toxic pesticide, as evidenced by studies
with laboratory and domestic animals, fish, other aquatic life, avian
species, wildlife and humans.

     The literature on clinical cases of acute parathion poisoning in
man is extensive.  In nearly all instances, however, the amount iagested,
inhaled, or adsorbed was unknown.  An oral lethal dose is estimated to 'e
l-to-2 mg/kg of body weight; the largest nonfatal dose reported is 6.4 mg/kp,

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A 167e inhibition of RBC cholinesterase has been produced in man at a
dosage level of 0.1 mg/kg/day over a 42-day period, while the ingestion
of 7.5 rag/day of parathion for 9 days produced a reduction of plasma
cholinesterase of 27 to 327..

     The major cholinergic effects produced by parathion poisoning are
weakness, nausea, vomiting, excessive sweating, headache, excessive
salivation, difficulty in walking, miosis, and muscle fasciculations.
Electroencephalographic (EE6) changes resemble those seen in epileptics.

     There have been a few controlled investigations of the dermal ef-
fect of parathion on humans.  No certain conclusions have been drawn
from skin tests related to rates of absorption.  Paraoxon, the oxida-
tion product of parathion, however, does not appear to be hydrolyzed in
the skin.  In the controlled studies reported, the exposure of hand,
forearm or whole body (nude) to relatively high concentrations of
parathion had little adverse effect.  Exposure to parathion vapors for
3 hr did not significantly reduce plasma cholinesterase activity.

     The hazard from inhalation is said to be three times greater than
from oral ingestion.  Unfortunately, the test results that were re-
viewed do not report the actual concentration of parathion in the air
that was being breathed.  RBC cholinesterase and plasma cholinesterase
depressions of 98 and 83%, respectively, were reported for subjects
exposed to fumes from parathion.

     The acute toxicity of parathion to male rats is presented below:

     Route of entry              Measurement

     Oral                     LDso (mg/kg)

     Intraperitoneal          LD50 (mg/kg)

     Dermal                   LD50 (mg/kg)

     Inhalation               LC5Q (1 hr)

                              LC50 (4 hr)  (mg/4)

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     The collective data indicate that parathion is highly toxic to all
species tested thus far by all routes of administration.  There is usually
a lesser degree of toxicity produced by dermal exposure than by other
routes.  The vehicle is very important in dermal toxicity tests.  Episodes
of acute toxicity are more likely to occur in nature than are chronic
poisonings.  The pathology of chronic toxicity is similar to that found in
acute episodes.  The young are more susceptible than the mature organisms.
In rats, males appear to be less susceptible than females.  The symptoms
and mechanisms of physiological action in all species are essentially the
same.  Cholinesterase depression is a sensitive clinical measurement.
Pathological damage appears to be minimal even in chronic exposures.

     There is little available literature regarding parathion's effect on
reproduction.  Most of the reported studies were conducted on wild avian
species (ducks, pheasants, and partridges).  Findings indicated that 5-to-
10 ppm of parathion had little effect, if any, on egg production, fertility
or progeny growth.  There was no indication that parathion residues occur
in the egg.

     There were only two studies found on the mammalian teratogenesis of
parathion.  Although they showed that parathion caused a reduction in the
number of fetuses and an increase in the number of resorptions, they
provided little evidence that actual malformation of the fetus occurs
as a result of parathion exposure.  The data suggests that parathion
does not produce specific teratogenic effects.

     A large number of papers have been published regarding the effect
of parathion on the normal development of avian embryos.  Various
deformities have been produced when eggs are immersed in parathion or
the pesticide is introduced into the yolk sac.  Investigators have
reported lordosis of the neck, celosomia, retardation of the axial
skeleton, disorganized vertebral musculature, light edema, achondroplasia
and abnormal leg position.  Parathion reportedly acts as an antimitotic
substance that markedly effects cell division.  Generally, the dosage
of parathion was relatively high before deformation of the embryo
occurred.

     The available data concerning the effect of parathion on crustaceans
is meager.  The normal length of oyster larvae, however, is reported
to be greatly depressed by 1-ppm parathion in water.

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     Treatment of tissue cultures with parathion does not permit
prediction of the'activity that would be produced in the intact organism.
In a study with HeLa cells (a human malignant cell line) paraoxon was
less toxic than parathion, and nitrophenol was as toxic as parathion.
Furthermore, relatively high amounts of parathion have to be used in
tissue culture to produce a definitive response.  There is little
difference between malignant and nonmalignant cell responses to
parathion.

     There is practically no available literature on the induction of
chromosomal abnormalities by parathion.  However, abnormalities have
been induced by parathion in mitotic chromosomes of the guinea pig.

     No references were found on the oncogenic effect of parathion.
Parathion had no clear effect on chemically induced tumors.

     The following major points can be stated regarding the metabolism
of parathion:

      1.  Parathion is readily adsorbed through the skin, from the
          stomach and the lung.

      2.  It becomes widely distributed throughout the body but does
          not accumulate at any site and causes no effect other than
          the irreversible binding of paraoxon to cholinesterase.

      3.  The major metabolites of parathion that are excreted are
          aminoparathion, jj-nitrophenol, diethylphosphorothioic acid,
          ethylphosphoric acid and sulfate.

      4.  The biotransformation of parathion involves two distinct
          phenomena:  activation and detoxification.

      5.  Parathion is enzymatically oxidized to paraoxon by the mixed
          function oxidase system.

      6.  Microsomal oxidation of parathion requires NADP!^, oxygen,
          potassium chloride and magnesium ion for maximum activity.

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Food Tolerances and Acceptable Intake

     Tolerances for parathion have been established for about 100 raw
agricultural commodities in the United States; all but one are in the
0.1 to 1.0 ppra range.  The tolerances for parathion and methyl para-
thion are the same.  When both chemicals are present, the tolerances
apply to the combined total of methyl parathion and parathion.

     The acceptable daily intake (ADI) for parathion has been set at
0.005 mg/kg body weight.

Environmental Effects

     Parathion is toxic to fish and wildlife; product labels carry a
warning that wildlife in treated areas may be killed.  A brief summary
of the acute toxicity of parathion to fish, anthropods and avian species
is as follows:

                           LC50 for Fish (ppm)

     Bluegill                    24 hr                 0.141
     Bluegill                    48 hr                 0.047
     Golden shiner               24 hr                 0.931
     Greenfish                   24 hr                 0.155
     Mummichog                   48 hr                 0.15
     Stripped mullet             96 hr                 0.125
     Tilapia                     96 hr                 0.375

                        LC5Q for Anthropods (ppm)

     Amphipod (Gammarus lacustris)           24 hr       0.012
     Amphipod (Gammarus lacustris)           48 hr       0.006
     Stonefly (Claassenia sabulosa)         24 hr       0.0088
     Stonefly (Pteronarcella badia)         24 hr       0.008
     Stonefly (Pteronarcys californica)      24 hr       0.028
     Stonefly (Pteronarcys californica)      48 hr       0.011
     Stonefly (Pteronarcys sp.)              48 hr       0.011
     Waterflea (Daphnia pulex)              48 hr       0.0004
     Waterflea (Daphnia sp.)                48 hr       0.00076

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                   Oral LD5Q for Avian Species (rag/kg)

     Chukar partridge                                  24.0
     House sparrow                                      1.3-3.4
     Japanese quail                                     6.0
     Mallard duck                                       1.0-2.1
     Pheasant                                          12.4
     Pigeon                                             2.5
     Quelea                                             1.8
     Red-winged blackbird                               2.4
     Starling                                           5.6

     Parathion is universally.recognized as being highly toxic to bees.
Studies of the toxicityof parathion to bees (Apis me 1 lifer a) by direct
topical application and by exposure to parathion containing solutions,
vapors and surface deposits have shown this pesticide to be highly
toxic by all routes tested.

     The reports reviewed during this study indicate that parathion would
permit survival of beneficial insects in some predator-parasite systems.
For example, the LD5Q of parathion to the English grain aphid (Macrosiphum
aenae)  is 1.8 Ug/g, while the LDjo for two of the aphids most numerous
ubiquitous predators  (Hippodamia convergens and Nabis americoferus) are
40 and 21 ug/g, respectively.  Such a favorable relationship, however,
does not exist in all systems.

     The available data also indicate that parathion is extremely toxic
to aquatic fauna, but relatively nontoxic to the lower aquatic flora.
A number of aquatic microorganisms degrade parathion.  Many of these
organisms also preferentially sorb and thus accumulate parathion from
aqueous media.  This sorption process may be independent of life pro-
cesses; sorption rates of live and dead organisms showed little differ-
ences.

      Only  limited data was found on the presence of parathion in the
air.  One  study reported on the parathion content of air inside and out-
side  the homes of workers occupationally exposed to this insecticide.
The results  indicated that parathion was present in the atmosphere,
thereby exposing the  total population of the area.  The presence of
parathion  residues in the air raises important questions, including the
origin of  such residues, their relationships to parathion use and
handling patterns in  the area, their persistence and transport patterns
in air, and  their significance to human and environmental health.
                                   8

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     The persistence of parathion in the natural aquatic environment is
apparently markedly affected by microbial activity.  One study indicated
that without microbial activity, parathion would remain in the environ-
ment for several months; in biologically active (aerobic or anaerobic)
environments, it would be degraded in a matter of weeks.

     Other investigators have concluded that it is unlikely that water
in deeper soil strata could become contaminated with insecticidal resi-
dues from the upper agricultural soil layers, or that parathion could
contaminate underground water supplies beneath any of these soils by
leaching under normal rainfall conditions.

     Laboratory, field, and monitoring data on the residues and fate of
parathion in the soil show that the persistence of this chemical varies
considerably, depending upon a number of factors.   Parathion residues in
the soil degrade by chemical hydrolysis as well as by microbial action.
The half-life of parathion in soil has been shown to be as short as 1.5
week.  In the case of heavy soil contamination, parathion residues have
been shown to persist for at least 16 years.

     Parathion is strongly adsorbed by organic matter.  Once adsorbed
the chemical becomes unavailable for insecticidal action, and appears
to be protected to a degree against degradation.  No data is available
on the fate of such adsorbed parathion residues; it is not known whether
they eventually degrade, or if and under what conditions they might be-
come reactivated by desorption.   No information appears to be available
on the fate of the initial degradation products, especially £-nitrophenol
and aminoparathion, or on the effects of these degradation products on
organisms other than mammals and insects.

     The two most important environmental transport mechanisms for para-
thion appear to be volatilization and surface runoff while absorbed on
solids.

     No data were found on the biomagnification of parathion.

Specific Hazards of Use

     The only major hazards associated with the registered uses of para-
thion that have been documented by this review are its acute toxic hazard
to man and, to a lesser degree,  its acute toxic hazard to many of the
other higher organisms.  Data were not found that  documented the associ-
ation of this hazard with any specific use of parathion.

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Limitations in Available Scientific Data

      The review of the scientific literature was based on available
sources, given limitations of time and resources.  Data was not found
in a number of pertinent areas:

      1.  The mechanism of tolerance to chronic parathion administration.

      2.  Chronic inhalation toxicity of parathion, based on cholinesterase
          inhibition and on unmistakable signs of toxicity.

      3.  The fate of parathion residues adsorbed on organic matter or
          other soil colloids.

      4.  The fate and effect in the environment of the major degradation
          products of parathion, especially 2.~n^tr°Phen°l an<* amino-
          parathion.

      5.  The persistence and fate of parathion residues in water,
          especially under field conditions.

      6.  The origin, presence, persistence and significance of
          parathion residue in air.

      7.  Parathion metabolism and residues in and on nontarget plants,
          and regarding the effects of these residues on wildlife feeding
          on such plants.

      8.  Effects on ecosystems.

Efficacy and Cost Effectiveness

      Parathion is registered for a wide variety of crops and pests;
yield changes and efficacy data have been  reported for numerous crop-
pest combinations.  However, because of inherent limitations in crop-test
data, only  order-of-magnitude estimates of economic benefits can be made.

      Parathion was reported to be effective when used on cotton to
control the bollworm and boll weevil, but  was much less effective for
control of  the tobacco budworm.  The budworm is more resistant to
parathion than to methyl parathion.  The results of one yield test
showed economic gains by the use of parathion on cotton of $93.98/acre.
                                    10

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     Effective control of the sorghum midge was achieved with parathion.
However, economic effects ranged from a loss of $10.00 to a gain of $5.00
per acre.  Rate and timing of application were important to the effect on
sorghum yield.

     Parathion also controls the greenbug on sorghum.  Reported yield
changes were variable, ranging from a loss of 458 pounds to a gain of
1,083 pounds per acre; economic benefits ranged from a loss of $12.80 to a
gain of $23.80/acre.  Some phytotoxicity was observed, however, when high
rates of parathion were used, and thus adversely affected yields from
some varieties of sorghum.

     Greenbug control on wheat ranged from 88% to 92%; economic benefits
ranged from $5.70 to $17.00/acre from the use of parathion.

     In two out of three tests conducted in Virginia, parathion greatly
reduced the amount of damage to peanuts caused by the southern corn
rootworm.  A control was not used in the third test, and there was no
explanation for not using it.  Economic benefits for the one test
reporting yields amounted to $26.50/acre.

     One application of parathion effectively controlled the European
corn borer and Western corn rootworm, with benefits ranging from $5.40
to $143.30/acre.

     Application of parathion to control the Pacific wireworm on po-
tatoes resulted in reductions of 78% to 95% in the amount of culls.
Economic benefits varied from a loss of $103.00 to a gain of $108.70/acre.

     Economic benefits for control of the potato aphid amounted to
$87.90/acre.  For the potato leafhopper, benefits were $504.50/acre.

     Parathion applied to lima beans at the time of first bloom resulted
in good control of Lygus hesperus and increased yields significantly.
Economic benefits for one test were $236.70/acre.

     The economic benefit for control of the pea aphid in one test was
$67.50/acre.

     Two applications of parathion appeared to provide satisfactory
control of the tarnished plant bug on strawberries.  The economic bene-
fits ranged from $527.70 to $905.70/acre.

     Cost effectiveness on a limited statistical basis was demonstrated
for four major crops including three major cotton pests, two sorghum pests,
one wheat pest, and two corn pests.   Additional data were presented on
three potato pests and three vegetable/fruit pests.
                                   11

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                   PART II.   INITIAL SCIENTIFIC REVIEW


                          SUBPART A.   CHEMISTRY


                                 CONTENTS

                                                                          Page

Synthesis and Production Technology 	  13

Physical Properties of Parathion 	  16

Analytical Methods 	  20

Composition and Formulation 	  30

  Wettable Powders	30
  Dusts	31
  Emulsifiable Concentrates 	  31
  Granules	.32

Chemical Properties, Degradation Reactions and Decomposition Process ...  32

  The Effect of Sunlight and Ultraviolet Radiation 	  34
  Hydrolysis	35
  The Effect of Heat	39
  Oxidation	40
  Reduction	40

Occurrence of Parathion Residues in Food and Feed Commodities 	  40

Acceptable Daily Intake 	  44

Tolerances	47

References	51
                                     12

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      This subsection contains a review of available data on parathion's
chemistry and presence in foods.  Eight subject areas have been examined:

      1.  Synthesis and-production technology.

      2.  Physical properties of parathion.

      3.  Composition and formulation.

      4.  Chemical properties, degradation reactions and decomposition
          processes.

      5.  Occurrence of residues in food and feed commodities.

      6.  Acceptable daily intake.

      7.  Tolerances.



Synthesis and Production Technology

      The chemical processes used for parathion and methyl parathion
manufacture are almost identical.  The only difference is in the alcohol
(methanol or ethanol) used in the initial reaction (with phosphorus penta-
sulfide).  The equipment for producing these compounds is identical.  In
most cases the same processing equipment is used for the manufacture of
both products.

      The following is a list of known parathion manufacturers and
production capacity and levels.
                                   13

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Manufacturer and
plant location
                        Plant
                      capacity!/       Estimated 1972  production
                   (million Ib/year)    of parathion (million Ib)
Monsanto Company
Anniston, Alabama
                         50
10
Stauffer Chemical
  Company
Mount Pleasant, Tennessee

Kerr-McGee Chemical
  Corporation
  Hamilton, Mississippi
  Los Angeles, California

Velsicol Chemical
  Corporation
  Bayport, Texas

Total
                         30
                          9
                          3
                         10

                        102
None
 1
None

14
Source:  MRI estimates.
af  Plant capacity is stated for methyl parathion plus (ethyl) parathion.
      Stauffer and Kerr-McGee have discontinued parathion production
      since 1972.
     Three reactions are involved in the synthesis of parathion:
P2S5
               S
               ii
        (C2H50)2PSH + C12
                                             H2S
                                   S
                                   ii
                           (C2H50)2PC1 + HC1 + S
             (1)


             (2)

        (C2H50)2PC1
                                (C2H50)2P>
N02 + NaCl   (3)
                                   14

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In the first two reactions, the intermediate diethyl phosphorothiono-
chloridate is produced.  This intermediate may be produced on site or else-
where, or can be purchased from another manufacturer.

     One of the most detailed descriptions of methyl parathion manufacture
is a 1953 U.S. patent.  Although this patent discusses methyl parathion
manufacture, the process description is applicable to parathion synthesis.
In the patent, Schrader (1953).!' describes the reaction 3 procedure for
the manufacture of methyl parathion.  According to Schrader's procedure,
this exothermic reaction is performed at 80 to 100°C.  However, according
to a patent by Dvornikoff et al. (1953),—' it is preferred to operate at
a much lower temperature of from -10 to +10°C.  The reaction is performed
at atmospheric pressure and requires a reaction time of 5 hr at 80 to 95°C
but about 18 hr if performed at 0°C.

     The reaction is conducted in the liquid phase.  One of various organic
solvents may be present.  An alcoholic medium is specified by Dvornikoff
et al. (1953).  However, an inert solvent such as benzene or chlorobenzene
is preferred by Schrader (1953).  Monsanto employs acetone as solvent.

     Copper powder may be used as a catalyst or the reaction may simply
be conducted in a copper reaction vessel, thereby shortening reaction
time appreciably.  A small amount of potassium bromide can be used as an
effective co-catalyst.  Aliphatic amine catalysts were cited for use in
this reaction by Toy et al. (1949).-/  At least 0.25% of such materials
as trie thy lamine, tributy lamine, N-ethyl morpholine and hexamethylene
tetramine may be used.

     The reaction is carried out in a stirred, jacketed vessel.  Although
the reaction is conducted at essentially atmospheric pressure, closed
vessels must be used because by-product gases are both toxic and odorous.

     The yield of methyl parathion is 90% or higher.  The reaction prod-
uct mixture may be pumped through a precoated filter to remove gummy im-
purities .  The filtrate may then be separated into aqueous and oily
layers.  The lower oily layer may then be washed with a dilute sodium
carbonate solution, then with water; it may then be steam distilled to
remove by-product trimethyl thiophosphate.  After cooling and settling,
I/  Schrader, G. (to Farbenfabriken Bayer), U.S. Patent No. 2,624,745
      (6 January 1953).
2/  Dvornikoff, M. N., et al. (to Monsanto Chemical Company), U.S. Patent
"     No. 2,663,721 (22 December 1953).
3/  Toy, A. D. F., et al. (to Victor Chemical Works), U.S. Patent No.
      2,471,464 (31 May 1949).
                                  15

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the organic Layer can be dried by heating under vacuum to give the
product.

     Monsanto produces parathion by a batch process in equipment dedi-
cated to methyl and ethyl parathion production.  Two of the raw materials
are produced on site and the rest are received by rail.  (See Table 1.)
A production schematic is shown in Figure 1.

     Stauffer's method of producing parathion is believed to be similar
to Monsanto ' s .

     No information is available concerning production methods at the
Kerr-McGee methyl parathion plant.  The plant at Hamilton does not produce
either ^2^5 or t*ie £~nitrophenol.

Physical Properties of Parathion

     Chemical Name:  0,0-Diethyl 0-£-nitrophenyl phosphorothioate

     Common Name:  Parathion

     Trade Names;  Alkron, Aileron, Bladan, Corothion, E-605, Ethyl
                   Parathion, Ethlon, Folidol E-605, Niran, Orthophos,
                   Panthion, Paramar, Parathene, Farawet, Phoskil,
                   Rhodiatrox, Soprathion, Stathion, Thiophos

     Pesticide Class;  Broad- spectrum nonsystemic insecticide; organo-
                       phosphate

     Structural Formula:  €21150  X
                                Tj
                               '
     Empirical Formula;

     Molecular Weight;  291.27

     Analysis;  C, 41.237.; H, 4.84%; 0, 27.47%; N, 4.81%; P, 10.64%;
                S, 11.01%

     Physical State;  Pure compound is a yellow liquid.  Technical mate
                      rial is an amber to dark brown liquid, with a
                      gar lie- like odor.
                                 16

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Table 1.  RAW MATERIALS AND BY-PRODUCTS IN THE MANUFACTURE OF PARATHION


Material
1. PS
2. C125

3. CfcHjOH
4. NaOC6H,N02
5 . Acetone
6. Soda ash


Material
1. RjS
2. HC1

3. S
4. NaCl

Raw Materials
Received Received
from by
On-site Tote bins
Louisiana Rail, tanks

Louisiana Rail, tanks
On-site
Southwest Rail, tanks
East; middle- Rail, tanks
west
Reaction By-Products
Amount produced
Form (Ib/lb AI)
Gas 0.06 calcd.
Gas 0.12 calcd.

0.11 calcd.
0.20 calcd.


Storage Remarks
Tote bins
Tank cars Vented to pro-
duction sys-
tem

Tank
Bulk For waste
disposal

Disposition Remarks
Flared S02 air pol-
lutant
Most re- Some to liquid
cycled waste
Incinerate S02 , some
H3P04?
Biol. waste Discharged to
treatment city sewer
Other Process Wastes and Losses

Material
Active ingre-
dient
Solvents
Other : Organo-
phosphates
p_-nitrophenol

Amount produced •
Form (Ib/lb AI)
Aqueous


Gas liquid




Disposition Remarks
Liquid waste < 1 ppm to
treatment city sewer
Burned
Liquid waste
treatment
Liquid waste
treatment
Source: Lawless, E. W., and T. L. Ferguson of Midwest Research Institute,
and R. von Rumker of RvR Consultants, The Pollution Potential
in Pesticide Manufacturing, for Environmental Protection Agency,
           Contract No.  68-01-0142 (January 1972).
                                      17

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              SO2
                t
              Flare
              H2S
            SO2


          Incinerator
C2H5OH-
            Reactor
^ Dmlkyl
  Ester
     CI2.
                                   •HCI-
Chlorinator
•Chloridothionate
     NaOC6H4NO2-
     Ace to ne	
                   Parathion
                   Unit
                                         NaCI-
      Na2CO3-
                             Waste
                             Treatment
                             Plant
                                                    City
                                                    Sewer
                                              Partial
                                              Recovery
                               Parathion
    Source:   Lawless  et al.,  op.  cit.  (1972)
              Figure 1.  Production schematic for parathion.
                                    18

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   Specific Gravity;  1.26 at 20/20°C

   Density:  10.5 Ib/gal at 20°C

   Melting Point;  6°C

   Boiling Point;  Thermally unstable and cannot be heated  to normal
                   boiling point, which is calculated  to be 375°C.
                   Various other boiling points are as  follows:

        Vapor pressure (mm Hg)          Temperature (°C)

          0.57 x 10"5                         20

          0.05                               113

          0.6                        -       157-162

        Bright et al. (1950)—' determined the following vapor pressures:

          3.78 x 10"5                         20

          2.08 x 10~4                         40

          9.31 x 10'4                         60

          3.52 x 10'3                         80

          1.15 x 10'2                        100

    Refractive Index;  n?5 = 1.5370

    Surface Tension;  39.2 dynes/cm at 25°C
I/  Bright,  N.  F.  H.,  J.  C. Cuthill, and H. H. Woodbury, "The Vapor
      Pressure  of  Parathion and Related Compounds," J. Sci. Food and Agr..
      1:344-348 (November 1950).
                                  19

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    Viscosity;  15.30 cp at 25°C

    Solubility;  Water at 25°C—24 ppm
                 Miscible with common organic solvents such as acetone,
                 benzene, carbon tetrachloride, chloroform, ethanol,
                 ether, toluene and xylene; slightly soluble in heptane
                 and petroleum oils; slightly soluble in lipids and fats,

    Flash Point (Tag Open Cup):  120°C

    Volatility;  0.09 mg/m3


Analytical Methods

      This subsection reviews parathion analytical methods and the
most significant of many primary information sources on the methods.
The following information sources are .described:  (1) The Pesticide
Analytical Manual (PAM), vols, I, III', (2) Official Methods of Analysis
of the Association of Official Analytical Chemiata|/. (3) Analytical
Methods for Pesticides and Plant Growth Regulators^/.

The Pesticide Analytical Manual - The Pesticide Analytical Manual (PAM),
published by the Food and Drug Administration, synthesizes procedures
and methods used by FDA laboratories to examine food samples for the
presence of pesticide residues.
I/  U.S. Department of Health, Education, and Welfare, Food and Drug
      Administration, Pesticide Analytical Manual. 2 vols. (1971).
2J  Association of Official Analytical Chemists, Official Methods of
      Analysis of the Association of Official Analytical Chemists.
      llth ed., Washington, D.C. (1970).
3/  Zweig, G., and J. Sherma, Analytical Methods for Pesticides and
      Plant Growth Regulators. Vol. VI;  Gas Chromatographic Analysis.
      Academic Press, New York (1972).
                                   20

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 The PAM is  published  in two volumes.  Volume  I  contains  procedures  for
 multi-residue methods (for smaples  of unknown history which may contain
 more than one pesticide).  Volume II contains analytical methods used
 for specific pesticide residues  and for  specific  foods.


Official Methods of Analysis of the Association of Official Analytical
Chemists - The Association of Official Analytical Chemists  (AOAC)
publishes an authoritative methods manual about every 5 years.  The
manual  is designed to provide both  research and regulatory  chemists with
reliable methods of analysis.   The reliability of the methods must be
demonstrated by a published study showing the reproducibility of the
method by professional analysts.

      When an AOAC method is adopted for the first time it is published
as "Official First Action."  This designation serves notice that final
adoption is pending,  and permits  an opportunity for any further study
that may be deemed appropriate.

      Methods that have performed successfully for at least 1 year are
raised to the status  of "Official Final Action."

      A few methods are adopted as "Procedures."  Such methods are
generally sorting or  screening methods  or well-established types of
examinations,  or auxiliary operations,  such as sampling or preparation
of a sample, which may not have been subjected to collaborative study.

Analytical Methods for Pesticides and Plant Growth Regulators, Volume
VI. Gas Chromatographic Analysis  - Chapter 6 of this text consists of
an extensive and detailed review  of  specific and multi-residue analytical
methods for organophosphate pesticides.   This reference provides im-
portant information not available in AOAC's "Methods of Analysis" or
the PAM such as: (1) a comparison  of  nine procedures for extracting
phosphorus insecticides and their metabolites from field-treated crops,
(2) a review of procedures for extracting organophosphate pesticides
from water samples, (3) a review  of  insecticide recoveries  from vege-
tables, (4)  a review  of various clean-up procedures, (5)  a  description
of various detectors,  (6) extensive  data comparing the relative re-
tention times of various pesticides  on  various column materials, and
(7) a review of the sensitivity of various gas Chromatographic systems.
                                  21

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Multi-Residue Methods

      Multi-residue methods for parathion are described in the AOAC
methods manual and PAM, Volume I.  Zwe.ig and Sherma have compiled a
detailed review of gas chromatographic residue analyses.

AOAC Methods - One of the AOAC methods ,i/ a general method for "chlorinated
and phosphated pesticides," is an "Official First Action" and applies only
to apples and lettuce.  A second AOAC multi-residue method?./ applies only
to "phosphated pesticides" (in kale, endive, carrots, lettuce, apples,
potatoes, and strawberries).  This second method is also an "Official First
Action" and involved a sweep codistillation cleanup for the organophosphate
residues.  (The cleanup is not adequate for electron capture detectors;
KC1 thermionic detectors must be employed.)  Also described in AOAC methods
manual^/ is a single sweep oscillographic-polarographic confirmation method.

      The following AOAC multi-residue method is used for chlorinated and
phosphated pesticides:  A thoroughly mixed sample is extracted with
acetonitrile.  Aliquots of the acetonitrile solution are diluted with
water and the pesticide residues are extracted into petroleum ether.
The residues are purified by chromatography on a Florisil column and
are eluted from the column with mixtures of petroleum and ethyl ethers.
The first eluate, (6% ethyl ether in petroleum ether) contains some
chlorinated pesticides and some phosphated pesticides.  However, methyl
parathion and parathion (and diazinon) are obtained in a second eluate
(15% ethyl ether in petroleum ether).  A third eluate (50% ethyl ether
in petroleum e'ther) contains malathion.  The eluates are concentrated,
and the residues are determined by gas chromatography and identified by
combinations of gas, thin-layer, or paper chromatography.

PAM Procedures - The PAM multi-residue methods (PAM, 1971) apply to the
wide variety of foods tested by the FDA.  However, the multi-residue
methods are not capable of detecting and measuring all pesticides.
Analytical schemes used in the detection of parathion are shown in
Figures 1 and 2.  The various parts of the schemes shown in Figures 1
and 2 are outlined in detail in the PAM.  (The numbers refer to the
chemical numbering system of PAM; the chapter numbers also refer to
PAM.)

      Parathion is more than 80% recovered in the 15% ethyl ether in
petroleum ether fraction from the Florisil column.  Over 80% recovery
is achieved from both fatty and nonfatty foods.

      Relative retention times of parathion are presented below for
various column packings; the corresponding response for various
detectors is also indicated.
I/  AOAC, op_. cit., p. 475 (1970).
2/  AOAC, op_. cit., p. 484 (1970).
3/  AOAc, 0£. cit., p. 487 (1970).
                                   22

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                       Electron Capture Detector
    Column
    packing

 10% DC 200 on
 Gas-Chrom Q
 (or Anakrom Q)

 15% QF-1,
 10% DC 200 on
 Gas-Chrom Q
    Column
    packing

 10% DC 200 on
 Gas-Chrom Q

 15% QF-1,
 10% DC 200 on
 Gas-Chrom Q
  Retention  time
relati've to aldrin
     (ratio)	

       0.98
       1.88
       Sulfur Detector

    Retention time
relative to sulphenone
	(ratio)	

        0.78
        0.71
    Response
(ng for 1/2 FSD*
at 1 x 10"9 AFS**)

       15
       Response
   (ug for 112 FSD*
       64 ohs)

         1.5
         1.5
 *  FSD = Full scale deflection.
**  AFS = Amps, full scale.
                               23

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                                  Figurr  2

              GENERAL SCHEME FOR MULTIPLE RESIDUES*
 Chlorinalrd (nonionic)
       210
   Organophosphates
        230
   See ScAem* 762**
                                Sample Preparation
                                     141
                                  Guideline! for
                                  Compositing
                                      142
                                  Extraction and
                                    Cleanup
                                   Chapter 2
                                      1
                                      I
                                Gas Chromatography
                                  (quantitative)
                                    Chapter 3
                                      I
                                   Thin Layer
                                 Chromatography
                                (semi - quantitative)
                                   Chapter 4
                                  Determinative
                                 Methods - other
                                    Chapter 5
                                Confirmatory Tests
                                    Chapter 6
                                                                   1
Chlorinated (tonic)
     220
 See Scheme 163
 *  The  numbers refer  to the decimal  numbering  system of  PAM.
       Chapter numbers  also  refer to PAM.
**  Scheme 162 is  presented in Figure 2.
Source:   PAM, 1971.
                                    24

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                                       Figure 3

ANALYTICAL SCHEME FOR CHLORINATED  (NONIONIC)  AND ORGANOPHOSPHATE RESIDUES*
                                 Clilorinalrd (Nonionic) 210
                                   Organopliospli.-iU <- 230
                                          1
                                  I'roxitnalc Percentage Watrr
                                and Fat in Foods and Feeds 202
               J-
                                          _L
            Fal'.v Foods
             211 231
Non Fatly Foods
  212    232
Extraction of Fat
211.13
1
Aeetonitrile
Partitioning
211.14
1

Extraction and
Partitioning
212.13


                                     FlorisU Column
                                       211.15





i
l
1
1
i

1 	
1
i
I
i




|


( 1
	 L 	 1
2nd Florisil j
Column i —
211.16 a \ ~~— *-
	 . 	 »
r

Acid-Celite
Column- ^.
211.16 b
& 2nd Florisil
Column







1
Gas Chromatography
Electron Capture and Thermionic
on ys em

Gas Chromatography
Electron Capture Detector
311
J



1
Thin Layer Chromutograph-
Chlorinated 410
Orgaiiophottpliates 430
1
ICM. I.M.I. ».

|

i
*-'"" '

i
: 	 1
%
l._.








2nd Florisil
Column
211.16 a
1

KgO-Celite
Column
211.16 c

	
Alkaline
Hydrolysis
211.16 d
& MgO-Cclitc
Column
_3







]


1

l
t



        *  The numbers  refer to  the decimal  numbering sy tern of PAM.   The
              primary analytical  scheme is  in bold type.   Additional cleanup
              and/or quantitation schemes are in italics.
        Source:  PAM,  1971.
                                          25

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                 Potassium Chloride Thermionic Detector
                            Retention time
       Column            relative to p;irathion           Response
       packing           	(ratio)	       (mg for 1/2 FSD*)

  107. DC-200 on                  1.00                        2
  Chromosorl  W-HP
  (or Gas Chrom Q)

  15% QF-1 + 10%
  DC 200 on Chromosorb           1.00                        2
  W-HP (or Gas Chrom Q)
 *  FSD = Full scale def le< tion.
**  AFS = Amps, full scale.
      The PAM does not provide response data for flame photometric
 detectors.  However, this type of detector is now widely used for the
 analysis of organophosphate residues, primarily because of the high
 degree of specificity in detecting phosphorus compounds.  A review of
 these and other detectors is provided by Zweig and Sherma  (1972)— .

 Residue Analysis Principles

       Both AOAC methods manual and PAM (Vol. II) describe methods for
 the specific analysis of parathion residues.  Zweig and Sherma?-'  have
 provided a review of specific residue analytical methods for parathion.

 AOAC Method (Official Final Action) - According to the AOAC methods/for
 specific analysis of parathion residues, parathion is extracted with
 benzene or 2-propanol-benzene, and the strip solution is clarified.
 I/  Zweig and Sherma, op. cit., p.  205  (1972).
 21  AOAC, op. cit., p. 508  (1970).
 3/  Zweig and Sherma, op. cit., p.  445  (1972).
                                   26

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Parathion is brought into aqueous solution and simultaneously reduced
to its amine with zinc and hydrochloric acid.  The amine is diazotized
and coupled with !I-(]-naphthyl)-ethylenediamine to form a colored
compound which is analyzed spectrophotemetrically.

      The practical working range for the Beckman DU spectrophotometer
is 0 to 200 ug parathion.

      The method has been employed for parathion residues in a wide
variety of fruits and vegetables.

PAM Methods - PAM (1967) lists three methods for specific residue
analysis.  The first two methods have been "tested in varying degrees
and are considered reliable without further validation for the product
applications indicated."  The third method has not been "thoroughly
tested through interlaboratory studies."

     The First Method - This method refers to the PAM procedure for
     organophosphate (PAM, 1971); this procedure is summarized in the
     "Multi-Residue Methods" section of this Appendix.

     The Second Method - This method refers to an AOAC procedure
     (AOAC, 1965)i/; A summary of an updated AOAC method is described
     in the preceding section.

     According to PAM (Volume II), the AOAC method is generally applic-
able to all products excluding fats and oils.

     The sensitivity is 0.2 ppm.

     Cole crops develop an interfering pink color, and blank values as
high as 1 ppm and over are not uncommon with some of these crops (Rolston
and Walton, 19632-/).

     Aniline and some aniline analogues interfere.  Methyl anthranilate,
which is found in grapes and citrus fruits, interferes.  The amount of
methyl anthranilate and hence the extent of interference differs with
the maturity and variety of the fruit.  (Taschenberg and Avens, 1960-5.'.
I/  AOAC, 0£. cit.. (1965).
2j  Rolston, L. H. and R. R. Walton, "Parathion Residues in Greens,"
      J. Econ. Entomol.. 56:169-172 (1963).
3Y  Taschenberg, E. F. and A. W. Avens, "Parathion and EPN Residue
      Studies on Concord Grapes," J. Econ. Entomol., 53:441-445 (1960).
                                  27

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      Taschenberg-and Avens used the procedure of Averell and Norris
(1948)!/, except that the benzene solution is repeatedly washed with
10% HC1 to remove interference.  Alternatively, parathion can be
determined by difference:  the anthranilate is determined before the
parathion is reduced and then both compounds are measured together
after reduction.  The difference in results represents the parathion.

      Decomposed leafy vegetables contain decomposition products which
are not removed by the clean-up procedure and which yield false results
for parathion.Z/

      The Third Method - The third method is a polarographic procedure
      which can be used as a rapid scanning technique (Gogan, 1963^/.
      The method has been tested on apples and several vegetables.
      Parathion quantities of less than 0.1 ppm have been determined.
      Methyl anthranilate does not interfere.  Methyl parathion, EPN,
      and PCNB give peaks sufficiently close to the parathion peak as
      to interfere with determination.  Recent studies by the author
      indicate that the procedure can be extended to fats and oils,
      except olive oil, where interferences have been encountered.

Formulation Analysis Principles

      Formulation analysis procedures for parathion are described
in AOAC "Methods of Analysis" (1970).  Additional information has
been provided by the Technical Service Division, Office of Pesticide
Programs of EPA.

AOAC Methods (Official Final Action) - The two AOAC methods are volumetric
(applicable to all forms of technical parathion) and colorimetric
(applicable to dusts and wettable powders).
I/  Averell, P. R. and M. V. Norris, "Estimation of Small Amounts of
      o, o-diethvl o-(p-nitrophenvl)thiophosphate." Anal. Chem.. 20(8):
      753-756 (August 1948).
2.1  Dow, M. L. (Food and Drug Administration), Personal communication
      to PAM editors (October 1961).
3/  Gogan, R. J., "Application of Oscillographic Polarography to the
      Determination of Organophosphorus Pesticides, II.  A Rapid
      Screening Procedure for the Determination of Parathion in Some
      Fruits and Vegetables," J. Assoc. Off. Agr. Chem.. 46(2):216-222
      (1963).
                                   28

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      The volumetric method!./  This involves a potentiometric titration
of the parathion amine (produced by reduction with zinc and hydrochloric
acid) with sodium nitrite.  p_-Nitrophenol in parathion is initially
removed by extraction (aqueous sodium carbonate) and determined by
ultraviolet spectrophotometry.

      The colorimetric methodl/  This involves an extraction of parathion
with alcohol followed by a hydrolysis of parathion with potassium
hydroxide to form potassium js-nitrophenate which is determined by ultra-
violet spectrophotometry.

EPA Method - In addition to the AOAC formulation methods, the Technical
Service Division of EPA employs a high-pressure liquid chromatographic
procedure for parathion analysis.  The method is described as follows^/:

      1.  Reagents -

          a.  Methanol,  ACS
          b.  Parathion standard of known purity.

      2.  Operating Conditions for Liquid Chromatograph - UV detector
          at 254 mm.  Operating conditions must be determined for the
          individual liquid chromatograph to achieve optimum sensitivity
          and resolution.

      3.  Procedure -

          a.  Standard preparation - Weigh 0.3 g parathion standard into
              a 100 ml volumetric flask, dissolve, and make to volume
              with methanol.

          b.  Sample preparation - Weigh a portion of sample equivalent
              to 0.3 g parathion into a glass-stoppered flask, add
              100 ml methanol, and shake well.
II  AOAC, op_.  cit.. p.  114 (1970).
2J  AOAC, op_.  cit.. p.  115 (1970).
3/  Bontoyan,  Warren R.,  TSD,  OPP,  EPA,  Personal Communication to
      Dr. Alfred Meiners (September 1974).
                                   29

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       4.  Determination - Using a high-pressure liquid syringe,
           alternately inject three 5 ul portions each of standard
           and sample solutions.  Measure the peak area for each
           peak and calculate the average for both standard and
           sample.  Adjustments in attenuation or amount injected
           may have to be made to give convenient size peaks.

       5.  Calculation -

           % parathion = (avg area sample)(ul std)(ug/ul std)(purity of std)(100)
                                    (avg area std)(ul sample)(ug/ul sample)

           (This method was developed by Elmer H. Hayes of the Beltsville
           Chemistry Laboratory, Technical Services Division, Chemical
           and Biological Investigations.)

Composition and Formulation

     The most common formulations of parathion are:   (a) wettable powder
concentrates (15  to 257o); (b) ready-to-use dry  dust  mixtures  (1 to  10%);
(c) emulsifiable concentrates (2 to 8 Ib/gal); (d) granules  (2  to 25%).

Wettable Powders - Parathion is often formulated as a wettable  powder
containing 15 to 25% active material.  Certain clays  perform very well
as an absorbent carrier in wettable powder formulations.   In addition to
the clay carrier, up to 5% of a wetting agent and a dispersing  agent are
required in the formulation.  After making the final  blend,  the formula-
tion must be ground to a very fine particle size to obtain maximum dis-
persion in the field spray mixture.
                                    30

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Dusts - Dry dust concentrates may be prepared by impregnating certain
absorbent clays with parathion.  Typical dry dust concentrates are:

                                      20% (Ib)          25% (Ib)

              Absorbent clay           79.4               74.3

              Parathion (98.5%)        20.6               25.7

                                      100.0              100.0

     Dry 1 to 2.5% field strength dusts may be prepared by diluting con-
centrates to the desired strength.  Secondary type diluents are used in
combination to produce the desired bulk density and flow characteristics.

     Many formulators prepare field strength dusts by direct impregna-
tion.  This is accomplished in the same manner as preparing a concentrate
except the mixer is first charged with the desired combination of diluents,
Typical direct impregnation formulations are:


                                      1%  (Ib)           27.  (Ib)

              Diluents                 98.8              97.8

              Parathion  (98.5%)         1.2               2.2

                                      100.0             100.0

Emulsifiable Concentrates - Parathion can be formulated into many emul-
sifiable concentrates.  Table 2 has four suggested formulations.
                                    31

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Granules - Large quantities of parathion granules are used to protect crop
plant roots from soil insects such as rootworms and wireworms.  The amount
of active ingredient in such formulations varies from 4 to 25% depending
on crop, insect and method or time of application.

     Granules from calcined or uncalcined clays are the most widely used
carriers for parathion.  Calcined granules are preferred because of their
lower susceptibility to dust formation  through attrition.

Chemical Properties, Degradation Reactions and Decomposition Processes

     Parathion is a specific chemical compound, 0,0-diethyl 0-p_-nitro-
phenyl phosphorothioate (Chemical Abstracts nomenclature).  The biologi-
cal effects of parathion are intimately  associated with two other com-
pounds, paraoxon (0,0-diethyl 0-£-nitrophenyl phosphate) and a thioate
isomer of parathion (0,S-diethyl 0-p_-nitrophenyl phosphorothiolate).  As
indicated below, these compounds are formed by oxidation and isomeriza-
tion of parathion.
             o
      (C2H50)2PO
         Parathion
      (C2H50)(C2H5S)PO
Thiolate isomer
      Compounds  of  this  kind are toxic primarily because  they react with
acetylcholinesterase.   The toxicity of parathion depends entirely upon
its  oxidative  conversion in vivo to paraoxon.   Parathion is  oxidized
enzymatically to paraoxon, but can also be oxidized to paraoxon by the
chemical action of atmospheric oxygen.  The atmospheric  oxidation is
                                      32

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              Table 2.  SUGGESTED FORMULATIONS FOR PARATHION
                        EMULSIFIABLE CONCENTRATES
 Ingredients
 Parathion (98.5%)
 Xylene
 Emu1sifter
 Parathion (98.5%)
 Xylene
 Emulsifier
 Parathion (98.5%)
 Xylene
 Emulsifier
 Parathion (98.5%)
 Emulsifier
 % by Wt

2 Ib/gal

 25.69
 69.31
  5.00
100.00

4 Ib/gal

 47.23
 45.27
  7.50
100.00

6 Ib/gal
8 Ib/gal

 80.27
 19.73
100.00
  Lb/Gal
8.1221/
1.996
                                                         10.118
Source:  Monsanto Company,  Agricultural Division,  "Parathion and Methyl
           Parathion"Technical Bulletin No.  AG-lb,"St.  Louis, Missouri (undated),
 a/   Equivalent to  2.0 Ib   of 100% parathion
      Specific  Gravity  at 25/15.6°C.  0.9485
      Solution  Point, °C.   Cannot Freeze
 b/   Equivalent to  4.0 Ib   of 100% parathion
      Specific  Gravity  at 25/15.6°C.  1.0318
      Solution  Point, °C.   Cannot freeze
 £/   Equivalent to  6.0 Ib   of 100% parathion
      Specific  Gravity  at 25/15.6°C.  1.1478
      Solution  Point, °C.   Cannot freeze
 d/   Equivalent to  8.0 Ib   of 100% parathion
      Specific  Gravity  at 25/15.6°C.  1.2142
      Solution  Point, °C.   Cannot freeze
                                   33

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accelerated by ultraviolet radiation  (Cook and Pugh,  1957;-^ Frawley
et al.,  1958-').  Paraoxon is much more  toxic than  parathion.  The forma-
tion of  paraoxon has been postulated  as  the cause of  observed  toxicities
much higher than expected from  the observed concentrations of  parathion
(Whalley et al., 1964^/) .  Paraoxon reacts 10,000 times faster with
acetylcholinesterase than does  parathion (Heath,
     The  thiolate isomer  of parathion also reacts with acetylcholines-
 terase  10,000  times faster than parathion.   The  isomerization reaction
 does not  proceed in vivo, but does  take place  in storage.  The presence
 of  the  contaminating  thiolate isomer has  invalidated many publications
 on  the  biochemical and  toxic properties of parathion (Heath, 1961).

 The Effect of  Sunlight  and Ultraviolet Radiation - Parathion was one of
 the first organic phosphorus compounds whose anticholinesterase activity
 was shown experimentally  to increase during  exposure to UV light and
 sunlight  (Pay ton, 19531/) .  Subsequent work  by Cook (19556-/) and Cook and
 Pugh (1957) indicated that the toxicity of parathion decreased under UV
 light,  but the in vitro anticholinesterase activity increased as the re-
 sult of the formation of  more polar products.  Frawley et al. (1958)
 found that the exposure of parathion to UV radiation resulted in a mix-
 ture of compounds including parathion, paraoxon  and oxidation and degra-
 dation  products.  A study by Mitchell (196lZ') indicated that most organic
JL/  Cook, J. W., and N. D. Pugh, "Quantitative Study of Cholinesterase-In-
      hibiting Decomposition Products of Parathion Formed by Ultraviolet
      Light," J. Assoc. Offie. Agr. Chem.. 40:277-281 (1957).
2_/  Frawley, J. P., J. W. Cook, J. R. Blake, and 0. G. Fitzhugh, "Effect of
      Light on Chemical and Biological Properties of Parathion," J. Agr.
      Food Chem.. 6(1):28-30 (January 1958).
3/  Whalley, P. J., R. H. Adams, and B. Combes, J. Amer. Med. Assoc.. 189(5):
      357 (1964).
4/  Heath, D. F., Organophosphorus Poisons» New York:  Pergamon Press
      (1961).
5/  Payton, J., "'Parathion1 and Ultraviolet Light," Nature. 171(4347):355-
      356 (21 February 1953).
(>/  Cook, J. W., "Paper Chromatography of Some Organic Phosphate Insecticides.
      V.  Conversion of Organic Phosphates to in vitro Cholinesterase In-
      hibitors by N-Bromosuccinimide and Ultraviolet Light," J. Assoc. Offie.
      Agr. Chem.. 38:826-832 (1955).
77  Mitchell, L. C., "Separation and Detection of Eleven Organophosphate
      Pesticides by Paper Chromatography," J. Assoc. Offic. Agr. Chem..
      44:643-712 (1961).
                                     34

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phosphorus compounds break down to form a wide variety of new compounds
on irradiation, but no attempt was made to characterize them.  Studies
by Koivistoinen and Merilainen (1962)-  demonstrated that both UV radia-
tion and sunlight changed parathion to several cholinesterase inhibitors.
On the basis of chromatographic behavior, the metabolites were identified
as paraoxon and the S-ethyl (thiolate) and S-phenyl isomers of parathion,
together with unknown products (Figure 2).  Gar and Kapiani (1956)—' and
El-Refai and Hopkins (1966)—  reported the production of similar mix-
tures by UV radiation.  When methyl parathion was exposed to both UV radia-
tion and sunlight, only the methyl homologue of paraoxon was identified
(Koivistoinen and Merilainen, 1962).

     Joiner et al. (1971)—  have probably performed the most extensive
research to date on photodegradation products of parathion.  They sub-
jected parathion to high-intensity ultraviolet radiation under artificial
and natural conditions for periods up to 35 days.  They detected 12 irradia-
tion products, seven of which had not previously been observed as irradia-
tion products.  These products are listed in Table 3.

     In a recent study of the photochemical degradation of parathion,
0,0,8-triethylthiophosphate was identified as the major product of the
photolysis in aqueous tetrahydrofuran or ethanol.  Minor products were
0,0,0-triethyIthiophosphate, paraoxon, and triethyIphosphate,  which was
formed by secondary photolysis of paraoxon (Grunwell and Erickson, 1973^').

Hydrolysis - Hydrolysis is perhaps the most important degradation reaction
of organic phosphorus insecticides, because hydrolysis virtually
destroys all insecticidal activity.
_!/  Koivistoinen, P., and M. Merilainen, "Paper Chromatographic Studies on
      the Effect of Ultraviolet Light on Parathion and Its Derivatives,"
      Acta Agr. Scand., 12:267-276 (1962).
2/  Gar, K. A., and R. Y. Kapiani, Proclamation of the International Con-
      ference of Peaceful Uses of Atomic Energy (1955), 12:185 (1956).
51  El-Refai, A., and T. L. Hopkins, "Parathion Absorption, Translocation,
      and Conversion to Paraoxon in Bean Plants," J. Agr. Food Chem., 14(6)
      588-592 (November-December 1966).
A/  Joiner, R. L., H. W. Chambers, and K. P. Baetcke,  "Toxicity of Para-
      thion and Several of Its Photoalteration Products to Boll Weevils,"
      Bull. Environ. Contam. Toxicol.. 6(3):220-224 (1971).
J5/  Grunwell, J. R., and R. H. Erickson, "Photolysis of Parathion (0,0-Di-
      ethyl-0-(4-nitrophenylthiophosphate).   New Products," J.  Agr. Food
      Chem., 21(5):929-931 (September-October 1973).
                                    35

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                                                                        S-phenyl isomer
(C2H50)2PON02
N02   +  HO
                                                                                                     NO,
                                                                                             j>-nitrophenol
                                                                   S-ethyl (thiolate)  isomer

Adapted from Dauterman, W. C., "Biological and Nonbiological Modifications of Organophosphorus Compounds,"
               Bulletin of the World Health Organization, 44(1-2-3):144 (1971).
                            Figure 4.  Major photodegradation products of parathion.

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         Table  3.   OTHER PHOTODEC RABATION PRODUCTS OF PARATHION
£-Aminopheno1
H0«   )>NH2
 Diethy1 phenyl phosphate
 (C2H50)2PO
Diethyl phenyl phosphorothioate
 (C2H50)2PO
Ethyl bis(p_-nitrophenyl) phosphate           C2H5OP  (°\(.)/N02) 2
Ethyl bis(p_-nitrophenyl) phosphorothioate    C2H^OPO
Diethyl phosphate
(C2H50)2POH
Monoethyl phosphate
C2H5OP(OH)2
Data from:  Joiner,  R.  L.,  Piss.  Abstr.  Int..  32:41698  (1971/1972).
                                    37

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      The  extent  of  hydrolytic  stability is,  in general,  related  to the
electronic  characteristics  of  the  substituents attached  to  the phos-
phorus  atom.   Thus,  the  replacement of a phosphorus-bound oxygen atom
with  a  sulfur  atom  usually  increases the resistance  of  the  molecule to
hydrolysis.  This fact probably accounts for the fact that  the chemical
structures  of  most  commercial  organophosphate insecticides  contain sulfur.

      In parathion  (and in methyl parathion)  there are three potential
groups  which may be hydrolyzed from the phosphorus portion  of the molecule.
However,  only  one,  the p_-nitrophenol group,  is of practical significance;
the hydrolysis of  the most  labile  group greatly increases the hydrolytic
stability of the remaining  groups.  For example, paraoxon has a  half-life
of 9.2  days at 25°C and  pH  10, diethyl phosphate, even at 100°C  and pH 10
has a calculated half-life  of  5 billion days (Heath, 1956;-/ Vernon,
               f\   _•«••_
       (C2H50)2PO @> N02     hydrolysis>

            paraoxon                     diethyl phosphate  j>-nitrophenol

                                       further
                                      hydrolysis

                                           H PO   +  2C-H.-OH
                                            34       2 5
                                  phosphoric  acid   ethanol
      Parathion is  relatively resistant to hydrolysis.   The  stability  of
parathion in water is  related to  pH and temperature.   Stable below pH 7,
it hydrolyzes  rapidly  in  alkaline solution.   The  rate  of hydrolysis also
increases appreciably  with increases in temperature.   Fifty percent
hydrolysis of  parathion is achieved in 2.7 hr at  pH 9  and 70°C, but 17 to
20 hr are required at  pH  1.   At pH 1 to 5, 690 days are required at 20°C
(Lawless  et al., 19733-/).
I/  Heath, D. F., "The Effects  of  Substituents  on the Rates  of Hydrolysis
      of  Some Organophosphorus  Compounds.   I.   Rates in Alkaline Solution,"
      J.  Chem. Soc.. pp.  3796-3804 (1956).
£/  Vernon, C. A., Chem.  Soc.  (London)  Spec. Publ.. 8:17  (1957).
J3/  Lawless, E. W., T. L. Ferguson,  and A.  F. Meiners (Midwest Research
      Institute), Methods  for the Disposal of Spilled and  Unused Pesticides
      (Draft), for Environmental Protection Agency, Contract No. 68-01-
      0098 (1973).
                                    38

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     In laboratory studies, the half-life of parathion in ethanol-pH 6.0
buffer solution (20:80) at 70°C was shown to be 43 hr (Ruzicka et al.,
1967- ).  with Thames River water (pH 8.0, total hardness as CaC03 314 rag)
substituted for buffer solution, the half-life was 65 hr; with Irthing
River water (pH 7.5, total hardness as CaC03 42 rag) substituted, the half-
life was 68 hr.  Hydrolysis under these conditions was a pseudo-first-order
reaction.

     In another hydrolysis rate study, 31.27» of parathion remained after
4 weeks in neutral water (Cowart et al., 1971?-').  Studying the persistence
of parathion, Mulla (1963>2/ found that, in the laboratory at pH 8, 35°C
and a light intensity of 64 ft-candles, parathion remained undegraded
after 96 hr; in the field, however, all the insecticide was lost within
72 hr.  The more rapid disappearance in the field studies was attributed
to wind action, breakdown by microbes, the presence of organic matter, and
complex edaphic factors such as absorption by soil colloids.

                                             4/
The Effect of Heat - Metcalf and March (1953)-  found that when parathion
was heated at 150°C for 24 hr, 80 to 90% decomposition resulted and degra-
dation products were formed.  Five of the compounds were identified:
parathion, paraoxon, £-nitrophenol, bis(£-nitrophenyl) thionophosphate,
and—the principal product—S-ethyl parathion.

     Heating most insecticidal organophosphates above 200°C results in
decomposition.  According to the National Agricultural Chemicals Associa-
tion (1968),1' parathion should not be heated above 100°C.  When heated
to decomposition, parathion emits highly toxic fumes of nitrogen oxides,
phosphorus, and sulfur compounds (National Agricultural Chemicals Associa-
tion, 1968).
JL/  Ruzicka, J. H., J. Thomson, and B. 8. Wheals, "The Gas Chromatographic
      Determination of Organophosphorus Pesticides - Part II.  A Compara-
      tive Study of Hydrolysis Rates," J. Chromatoe.. 31(1):37-47 (November
      1967).
2/  Cowart, R. P., F. L. Bonner, and E. A. Epps, Jr., "Rate of Hydrolysis
      of Seven Organophosphate Pesticides," Bull. Environ. Contarn. Toxicol.,
      6(3):231-234 (1971).
_3/  Mulla, M. S., "Persistence of Mosquito Larvicides in Water," Mosquito
      News, 23(3):234-237 (September 1963).
4/  Metcalf, R. L., and R. B. March, "The Isomerization of Organic Thiophos-
      phate Insecticides," J. Econ. Entomol.. 46:288-294 (April 1953).
5J  National Agricultural Chemicals Association, Safety Guide for Ware-
      housing Parathions. Washington, B.C. (1968).
                                     39

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     The hazards from fires involving organic phosphorus insecticides have
been investigated and it was concluded  that:  first, most of the insecti-
cide is destroyed by decomposition before it can evaporate; second, over
907o of  the evaporating  insecticide is destroyed by  the flames; and third,
the evaporating portion is considerably diluted by  the time it reaches
anyone  (Smith and Ledbetter, 197li').

Oxidation - Several chemical oxidizing  agents are capable of replacing
the sulfur atom in parathion with an oxygen atom.   Koivistoinen and
Merilainen (1962) showed that when parathion was exposed as a thin film,
trace amounts of paraoxon were formed even in the absence of light.

                                               2 /
     A  recent publication  (Gunther et al., 1970=-')  pointed out that para-
thion can be rapidly and conveniently oxidized to paraoxon by means of
ozone (20 to 40% conversion).

                           3/
     Comma and Faust (1971)—  noted that chlorine or potassium permanganate
would convert dilute solutions of parathion in water to paraoxon.

Reduction - Reducing agents (for example, metals in acid medium) convert
parathion to the corresponding amino compound, aminoparathion (Melnikov,
19712').
The product, 0,0-diethyl 0-4-aminophenyl  thiophosphate , is nontoxic to
animals and does not have an insecticidal effect.

Occurrence of Parathion Residues in Food  and Feed Commodities

     The Food and Drug Administration, Department of Health, Education,
and Welfare, monitors pesticide residues  in the nation's food supply
I/  Smith, W. M., Jr., and J. 0. Ledbetter,'"Hazards from Fires Involving
      Organophosphorus Insecticides." Amer. Ind. Hyg. Assoc. J.. 32(7):468-
      474  (July  1971).
2/  Gunther, F.  A., D. E. Ott, and M. Ittig, "The Oxidation of Parathion
      to Paraoxon.  II.  By Use of Ozone," Bull. Environ. Contarn. Toxicol.,
      5(l):87-94 (1970).
^/  Comma, H. M., and S. D. Faust, "Chemical Oxidation of Organic Pesti-
      cides in Aquatic Environments," Paper No. 48, 161st American Chemi-
      cal Society Meeting, Los Angeles, California (29 March-12 April 1971)
b/  Melnikov, N. N., Chemistry of Pesticides, Springer-Verlag, New York,
      pp. 324-329 (1971).
                                    40

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through two programs.  One program, commonly known as the "total diet  pro-
gram," involves the examination of food ready to be eaten. This investiga-
tion 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 analysis.  The other program involves the examination
of large numbers of samples, obtained when lots are shipped in interstate
commerce, to determine compliance with tolerances.  These analyses are
complemented by observation and investigations in the growing areas to
determine the actual practices being followed in the use of pesticide
chemicals.

     A majority of the samples collected in these programs are categorized
as "objective" samples.  Objective samples are those collected where there
is no suspicion of excessive residues or misuse of the pesticide chemicals.
All samples of imported foods and fish are categorized as "objective"  sam-
ples even though there may 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  pat-
terns.  The food items are separated into 12 classes of similar foods  and
prepared for consumption by dietitians in institutional kitchens.  After
preparation, the food items are composited into 12 classes of similar
foods (e.g., dairy products; meat, fish and poultry; legume vegetables;
and garden fruits) for more reliable analysis and to minimize the dilu-
tion 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 Household Economics Research Division,  USD A, and represents the
high-consumption level of a 16- to 19-year-old male.  Each sample represents
a 2-week supply of food.

     Surveillance samples are generally collected at major harvesting and
distribution centers throughout the U.S. and 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 food are collected when offered for entry into the
United States.

     The results obtained during the 5-year period, June 1964 to April
1969, are compared in Table 4 with the acceptable daily intake (ADI)
                                    41

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      Total organo-
        phosphates
                          Table 4.  DIETARY INTAKE OF PARATHION AND TOTAL ORGANOPHOSPHATES

Compounds
Parathlon

1964-1965
0.000001
Milligrams /kilogram body weight/day
total diet studies
1965-1966 1966-1967 1967-1968
0.000005 0.00001.
5-Year
1968-1969 average
0.00001 0.00001
                                0.00014
0.00025
0.00007
0.00023
0.0002
K)
Data from Duggan, R. E., 6. Q. Lipscomb, E. L. Cox, R. E. Heatwole, and R. C. King,
  "Pesticide Residue Levels in Foods in the United States from 1 July 1963 to 30 June
  1969." Pest. Monit. J.. 5(2):73-212 (September 1971).

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established by the Food and Agricultural Organization, World Health
Organization (FAO/WHO) Expert Committee (FAO/WHO, 1970l/).  The
amount of parathion and total organophosphates calculated from this
high-consumption diet, approximately twice that consumed by a normal
individual, are well below the daily intake regarded as safe by the
FAO/WHO Expert Committee (Duggan et al., 1971).2J

      Table 5 (Duggan et al., 1971) compares the incidence and daily
intake in milligrams of parathion found in these samples for each of
the 5 years.

           Table 5.  AVERAGE INCIDENT AND DAILY INTAKE OF PARATHION
      1965-1966
            1966-1967
                      1967-1968
                             1968-1969
Percent
positive
  com-
positesa/

  1.0
Daily
intake
  (mg)

<0.001
Percent
positive
  com-
pos ities^-'

  1.4
       Percent
Daily  positive
intake   com-
 (mg)  posites
0.001
0.6
        Percent
 Daily  positive
 intake   com-
  (mg)   posites

< 0.001   3.3
 Daily
 intake
  (mg)

< 0.001
a/  312 composites examined.
b_/  360 composites examined.
      The results of the FDA analytical studies are tabulated for the
following food classes:
      Dairy Products
      Large Fruits
      Small Fruits
      Grains and Cereals (Human)
      Leaf and Stem Vegetables
      Vine and Ear Vegetables
      Root Vegetables
      Beans
      Red Meat
                           Poultry
                           Eggs
                           Fish
                           Shellfish
                           Grains (Animal)
                           Infant and Junior Foods
                           Tree Nuts
                           Vegetable Oil Products
I/  FAO/WHO, Food and Agricultural Organization of the United Nations/World
      Health Organization, 1969 Evaluations of Some Pesticide Residues in
      Food, The Monographs. Geneva (1970).
2/  Duggan, R. E., G.Q. Lipscomb, E.  L. Cox, R. E. Heatwole, and R. C. King,
      "Pesticide Residue Levels in Foods in the United States from 1 July 1963
      to 30 June 1969," Pest. Monit.  J.. 5(2):73-212 (September 1971).
                                  43

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     The most recently available analytical data are presented in Table 6
which lists  the incidence and ranges of  levels for parathion detected in
the various  food classes.  The omission  of any food class from the table
indicates  that no residues were found.

     The available data cover the years  1964  to 1969.  Limited data are
available  for the year 1970  (Corneliussen, 1972-'), and a complete update
on pesticide residue data is expected in the  forthcoming September 1974
issue of the Pesticide Monitoring Journal.

Acceptable Daily Intake

     The acceptable daily intake (ADI) is defined as the daily intake which,
during an entire life-time, appears to be without appreciable risk on the
basis of all known facts at the time of  evaluation (Lu, 1973?-/).  It is
expressed  in milligrams of the chemical  per kilogram of body weight (mg/
kg).

     For parathion the ADI is 0.005 mg/kg.  This level was set at the 1965
Joint Meeting of the FAO Committee on Pesticides in Agriculture and the
WHO Expert Committee on Pesticide Residues (FAO/WHO, 19683-/) .  A joint
meeting is held annually and new evidence is  considered which would war-
rant a change in the ADI of any pesticide.  The level for parathion has
not been changed through 1971 (FAO/WHO,1972-').

     In making the evaluation, all available  research on parathion con-
cerning its  biochemical effects, toxicology,  and teratology is considered.
^/  Corneliussen, P. E., "Residues  in Food and Feed:  Pesticide Residues
      in Total Diet Samples  (VI),"  Pest. Monit. J.. 5(4):313-329  (March 1972)
2_/  Lu, F. C., "Toxicological Evaluation of Food Additives and Pesticide
      Residues and Their 'Acceptable Daily Intakes' for Man:  The Role of
      WHO, in Conjunction with FAO," Residue Rev., 45:81-93  (1973).
3/  FAO/WHO, Food and Agricultural  Organization of the United Nations/WorId
      Health Organization, 1967 Evaluations of Some Pesticide Residues in
      Food, The Monographs,  Geneva  (1968).
4/  FAO/WHO, Food and Agricultural  Organization of the United Nations/WorId
      Health Organization, "Pesticide Residues in Food," Report of the 1971
      Joint FAO/WHO Meeting  on Pesticide Residues, World Health Organization
      Tech. Rept. Series No. 502, Geneva (1972).
                                    44

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Table 6.  PERCENT DISTRIBUTION OF PARATHION RESIDUES
   BY FISCAL YEAR IN DIFFERENT QUANTITATIVE RANGES

Percent distribution of samples
Domestic
Range ppm

No. samples
None found
Trace-0.03
0.04-0.10
0.11-0.50
0.51-1.00
1.01-1.50
1.51-2.00
Above 2.00

No. samples
None found
Trace-0.03
0.04-0.10
0.11-0.50
0.51-1.00
1.01-1.50
1.51-2.00
Above 2.00
1964-67

2.361
96.86
1.56
0.80
0.72
0.04
-
-
-

825
95.75
2.18
1.33
0.60
0.12
-
-
-
1968

1.512
94.97
2.71
1.52
0.60
0.20
-
-
-

398
95.48
3.77
0.50
0.25
-
-
-
-
1969

844
93.36
4.38
0.95
1.18
0.12
-
-
-

384
95.57
2.60
1.04
0.78
-
-
_
-
Imported
Total 1964-67 1968 1969
Large fruits
4.717 2.018 155 94
95.63 99.50 92.26 98.94
2.44 0.29 1.29 1.06
1.06 0.09 2.58
0.76 0.09 1.94
0.11 - 1.29
0.65
...
.
Small fruits
1.607 123 57 144
— ™*^^™-» wn^B* Xt^ ^HI^H
95.64 99.18 100.00 99.31
2.68 - - 0.69
1.06 ...
0.56 0.81
0.06 ...
0.65
- .
...

Total

2.267
98.99
0.40
0.26
0.22
0.09
0.04
.
-

324
99.38
0.31
.
0.31
.
0.04
—
-
Grains and cereal for human use
No. samples

None found
Trace-0.03
0.04-0.10
0.11-0.50
0.51-1.00
1.01-1.50
1.51-2.00
Above 2.00

No. samples
None found
Trace-0.03
0.04-0.10
0.11-0.50
0.51-1.00
1.01-1.50
1.51-2.00
Above 2.00
2.107
99.57
0.33
0.09
-
-
.
-
-

5.780
88.14
4.15
2.49
3.94
0.76
0.27
0.06
0.15
877
98.75
1.14
.
0.11
_
_
.
-

2.251
80.36
9.02
5.29
4.09
0.89
0.18
0.09
0.09
1§1
99.14
0.86
_
.
_
.
•
-

1.782
75.08
9.60
6.34
7.24
0.84
0.39
0.22
0.28
3.565 20 8 4
99.30 100.00 100.00 100.00
0.62 ...
0.06 ...
0.03 ...
— — — •
— • • -.
• • «• «
...
Leaf and stem vegetables
9.813 35 8 19
83.99 100.00 100.00 94.74
6.26 - - 5.26
3.83 ...
4.58 ...
0.81 ...
0.28 ...
0.10 ...
0.16 ...
32
100.00
w
—
—
—
_
.
-

62
SS^
98.39
1.61
.
m
—
^
^
_
                          45

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                                      Table 6.  (Concluded)

Percent distribution of samples
Domestic
Range ppm

No. samples
None found
Trace -0.03
0.04-0.10
0.11-0.50
0.51-1.00
1.01-1.50
1.51-2.00
Above 2.00
1964-67

4.401
98.44
0.88
0.38
0.23
0.02
-
0.02
-
1968

1.059
94.62
3.97
1.04
0.38
-
=
-
-
1969 Total
Vine and ear
848 5.308
94.69 97.08
3.18 1.87
1.42 0.68
0.71 0.34
0.02
-
0.02
-
Imported
1964-67 1968
vegetables
1.040 254
95.09 83.46
2.88 11.81
1.44 3.94
0.48 0.79
0.09
• -
.
-
1969

280
75.00
18.93
2.86
2.86
0.36
-
-
-
Total

1.574
80.64
7.18
2.10
0.95
0.13
-
-
-
Root vegetables
No. samples
None found
Trace-0.03
0.04-0.10
0.11-0.50
0.51-1.00
1.01-1.50
1.51-2.00
Above 2.00
5.425
99.26
0.55
0.14
0.01
0.01
-
-
-
1.758
97.50
1.59
0.34
0.40
0.11
-
-
0.06
1.060 8.243
97.55 98.67
1.70 0.92
0.66 0.25
0.09 0.11
0.04
» -•* -
-
0.01
165 66
100.00 100.00
-
-
-
-
-
-
-
89
95.51
2.25
2.25
-
-
-
-
-
320
98.75
0.62
0.62
-
-
-
-
-
Beans
Mo. samples
None found
Trace-0.03
0.04-0.10
0.11-0.50
0.51-1.00
1.01-1.50
1.51-2.00
Above 2.00
681
98.82
0.29
0.73
0.14
-
-
-

106
99.06
-
0.94
-
-
-
-

81 868
97.53 98.73
2.47 0.46
0.69
0.12
-
-
-

79 27
87.34 74.07
6.32 11.11
3.79 11.11
2.53 3.70
-
-
-

24
66.67
16.67
8.33
4.17
4.17
-
-

130
80.77
9.23
6.15
3.08
0.77
-
-

Data from Duggan et al., OP. ft.it.  (1971).
                                                    46

-------
Tolerances

U.S. Tolerances - Section 408 of the Food, Drug and Cosmetic Act, as amended
gives procedures for establishing tolerances for pesticide chemicals on raw
agricultural commodities.  Section 409 applies to food additives, including
pesticide chemicals on processed foods.  Tolerances are published in the
Code of Federal Regulations, Title 40, and in the Federal Register.  When
both methyl parathion and parathion are present, the tolerances apply to
their combined total.  A summary of current U.S. tolerances for parathion
on raw agricultural commodities is presented in Table 7.

     According to Lu (1973), U.S. tolerances which are established should
not result in the maximum ADI being reached each day.   He gives the following
reasons:

         1.  The tolerance reflects the maximum level of residue
             resulting from good agricultural practice, but this level
             is often not reached.

         2.  The tolerance is based on the assumption that the particular
             pesticide is used on all food in the class in question, and
             this is rarely the case.

         3.  Much of the residue will be lost in storage,  processing and
             cooking.

     The  tolerances are also based upon the entire product as purchased in
the market.  However, the product, as purchased, may not be entirely
consumed.
                                    47

-------
                                                  Table 7.   SUMMARY OF U.S. TOLERANCES FOR PARATHION AND/OR METHYL PARATHION
                                                                         ON RAW AGRICULTURAL COMMODITIES £/
00
                           pptn
                                                                        BBS
0.1 (N)
1.25
5
1
1
1
1
1
1
1

1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0.75
1
1
1
1
1
1
Almonds
Alfalfa fresh
Alfalfa hay
Apples
Apricots
Artichokes
Avocados
Barley
Beans _ ___
Beets (with or without
tops)
Beet greens
Blackberries
Blueberries (huckleberries)
Boysenberrles
Broccoli
Brussels sprouts
Cabbage
Carrots
Cauliflower
Celery
Cherries
Citrus fruits
Clover
Collards
Corn
Corn forage
Cottonseed
Cranberries
Cucumbers
Currants
Dates
Dewberries
Eggplants
1
1
0.1
1
1
1
1
1
1
1
1
1
1
1
1
1
0.2
1
1
1
1
1
1

1
1
1
1
1
1
0.1
1
1
1
                                                                            (H)
                                                                            (1)  00
                                                                                              Crop
                                                                                                              ppm
Crop
Endive (eacarole)
Figs
Filberts
Garlic
Gooseberries
Grapes
Grass for forage
Guavas
Hops
Kale
Kohlrabi
Lettuce
Loganberries
Mangoes
Melons
Mustard greens
Mustard seed
Nectarines
Oats
Okra
Olives
Onions
Parsnips (with or
without tops)
Parsnip greens
Peaches
Pea forage
Peanuts
Pears
Peas
Pecans
Peppers
Pineapples
Plums (fresh prunes)
0.9 (1) (N)
1
1
1

1
0.2
1
1
1

1
0.5 (1) (N)
0.1 (1) (N)
0.1 (1) (N)
1
0.1
1
1
1
0.1 (1) (N)
0.1 (1) (N)
1
0.2
0.1 (1) (N)
1
1
1

1
1
0.1 (1) (N)
1
1
Potatoes
Pumpkins
Quinces
Radishes (with or with-
out tops)
Radish tops
Rapeseed
Raspberries
Rice
Rutabagas (with or with-
out tops)
Rutabaga tops
Rye
Safflower seed
Sorghum
Soybean hay
Soybeans
Spinach
Squash
Strawberries
Sugar beets
Sugarcane
Stunner squash
Sunflower seed
Sweet potatoes
Swiss chard
Tomatoes
Turnips (with or with-
out tops)
Turnip greens
Vetch
Walnuts
Wheat
Youngberrlea
                           Administrative  guidelines  - none.
                           Tolerances  pending. -  all Interim tolerances above.
                           (1)  -  Interim tolerances.
                           (N)  -  Negligible  residue tolerances.
                           Source:   Reprinted from Pesticide  Chemical Hews Guide  of Food Chemical News,  Inc., by  permission of the
                                      publisher, first published 1 May 1974.
                           a/  Tolerances  apply  to combined methyl parathlon and  parathlon  residue  If  both  are  present.

-------
International Tolerances - Tolerances established by individual nations may
be based on recommendations of the FAO/WHO Expert Committee on Food Additives.
The Committee evaluates all residue data submitted by interested parties and
uses the following criteria (FAO/WHO, 1962,—') for making tolerance
recommendations:

     1.   Decide upon the effective level of the food additive under
         consideration that would be needed in good technological
         practice.

     2.   Examine the possible  uses and list all the foods in which
         the food additive might  be used.

     3.   Calculate the daily intake level that might occur if the
         food additive was used in all the foods for which it might
         be a useful additive, working on the basis of  the average
         intake of the food materials containing the additive.  This
         average intake for appropriate population groups is obtained
         from national food consumption surveys.

     4.   Obtain the necessary  information from which to calculate the
         average body weight of the population group concerned (usually
         between 50 to 70 kg).

     5.   From this information, calculate the intake of the  additive
         in milligrams per kilograms of body weight per day.

     6.   Check the figure against the acceptable intakes given for the
         substances in the table.  If it falls within the unconditional
         intake zone, the situation is satisfactory and the  level
         proposed may be accepted.  If it falls within  the conditional
         intake zone, further  scientific advice is required  before the
         level of use proposed is accepted.
I/  FAO/WHO, Food and Agricultural Organization of the United Nations/
      World Health Organization,  "Evaluation of the Toxicity of a Number
      of Antimicrobials and Antioxidants," Sixth Report,  Joint FAO/WHO
      Expert Committee on Food Additives,  World Health Organization Tech.
      Kept. Series No. 228. Geneva (1962).
                                    49

-------
     The validity of  criteria  for determining  tolerances was  reaffirmed
at the 1966 FAO/WHO,  196?!/).

     The recommendations for parathion  tolerances established by the 1969
Joint Meeting of the  FAO and WHO  (FAO/WHO,  1970) are:


             Vegetables (except carrots)                  0.7 ppm

             Peaches, apricots, other fresh fruits        1.0 ppm

             Other fresh fruits                           0.5 ppm
I/  FAO/WHO, Food and Agricultural Organization of the United Nations/
      World Health Organization, "Specifications for the Identity and
      Purity of Food Additives and Their Toxicological Evaluation:
      Some Emulsifiers and Stabilizers and Certain Other Substances,:
      10th Report, Joint FAO/WHO Expert Committee on Food Additives,
      World Health Organization Tech. Kept. Series No. 373. Geneva (1967),
                                    50

-------
References

Association of Official Analytical Chemists, Official Methods  of Analysis
  of the Association of Official Analytical Chemists, llth ed.,
  Washington, D.C.  (1970).

Averell, P. R. and M.  V. Norris, "Estimation of Small Amounts of 0,0-
  diethyl 0-(2-nitrophenyl)thiophosphate," Anal. Chem..  20(8):753-756
  (August 1948).

Bright, N. F. H., J. C. Cuthill, and N. H. Woodbury, "The Vapor Pressure
  of Parathion and Related Compounds," J. Sci.  Food and Agr.. 1:344-348
  (November 1950).

Cook, J. W., "Paper Chromatography of Some Organic Phosphate Insecticides.
  V. Conversion of Organic Phosphates to in vitro Cholinesterase In-
  hibitors by N-Bromosuccinimide and Ultraviolet Light," J. Assoc. Offic.
  Agr. Chem.. 38-826-832  (1955).

Cook, J. W., and N. D. Pugh, "Quantitative Study of Cholinesterase-
  Inhibiting Decomposition Products of Parathion Formed by Ultraviolet
  Light," J. Assoc. Offic. Agr. Chem.. 40:277-281 (1957).

Corneliussen, P. E., "Residues in Food and Feed:  Pesticide Residues
  in Total Diet Samples (VI)," Pest. Monit. J., 5(4):313-329 (March 1972).

Cowart, R. P., F. L. Bonner, and E. A. Epps, Jr., "Rate of Hydrolysis
  of Seven Organophosphate Pesticides," Bull.  Environ. Contam.  Toxicol.,
  6(3):231-234 (1971).

Dauterman, W. C., "Biological and Nonbiological Modifications of Organo-
  phosphorus Compounds," Bulletin of the World Health Organization,
  44(1-2-3):144 (1971).

Duggan, R. E., G. Q. Lipscomb, E. L. Cox, R. E. Heatwole, and R. C. King,
  "Pesticide Residue Levels in Foods in the United States from 1 July 1963
  to 30 June 1969," Pest. Monit. J.. 5(2):73-212 (September 1971).

Dvornikoff, M. N., et al.  (to Monsanto Chemical Company), U.S. Patent No.
  2,663,721 (22 December 1953).

El-Refai, A., and T. L. Hopkins, "Parathion Absorption,  Translocation,
  and Conversion to Paraoxon in Bean Plants,"  J. Agr. Food Chem.,
  14(6):588-592 (November-December 1966).

FAO/WHO, Food and Agricultural Organization of the United States/World
  Health Organization, "Evaluation of the Toxicity of a Number  of Anti-
  microbials and Antioxidants," Sixth Report,  Joint FAO/WHO Expert
  Committee on Food Additives, World Health Organization Tech.  Rept.
  Series No. 228. Geneva  (1962).
                                    51

-------
FAO/WHO, Food and Agricultural Organization of the United Nations/World
  Health Organization, "Specifications for the Identity and Purity of
  Food Additives and Their Toxicological Evaluation:  Some Emulsifiers
  and Stabilizers and Certain Other Substances,"  10th Report, Joint
  FAO/WHO Expert Committee on Food Additives, World Health Organization
  Tech. Rept. Series No. 373. Geneva (1967).

FAO/WHO, Food and Agricultural Organization of the United Nations/World
  Health Organization, 1967 Evaluation of Some Pesticide Residues in
  Food. The Monographs. Geneva (1968).

FAO/WHO, Food and Agricultural Organization of the United Nations/World
  Health Organization, 1969 Evaluations of Some Pesticide Residues in
  Food. The Monographs. Geneva (1970).

FAO/WHO, Food and Agricultural Organization of the United Nations/World
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  Joint FAO/WHO Meeting on Pesticide Residues, World Health Organization
  Tech. Rept. Series No. 502. Geneva (1972).

Frawley, J. P., J. W. Cook, J. R. Blake, and 0. G. Fitzhugh, "Effect of
  Light on Chemical and Biological Properties of Parathion," J. Agr.
  Food Chem.. 6(1):28-30 (January 1958).

Gar, K. A., and R. Y. Kapiani, Proclamation of the International Conference
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Gogan, R. J., "Application of Oscillographic Polarography to the
  Determination of Organophosphorus Pesticides, II.  A Rapid Screening
  Procedure for the Determination of Parathion in Some Fruits and
  Vegetables." J. Assoc. Off. Agr. Chem.. 46(2):216-222  (1963).

Comma, H. M., and S. D. Faust, "Chemical Oxidation of Organic Pesticides
  in Aquatic Environments," Paper No. 48, 161st American Chemical Society
  Meeting, Los Angeles, California (29 March - 12 April 1971).

Grunwell, J. R., and R. H. Erickson, "Photolysis of Parathion (0,0-
  Diethyl-0-(4-nitrophenyl)thiophosphate).  New Producers," J. Agr.
  Food Chem.. 21(5):929-931 (September-October 1973).

Gunther, F. A., D. E. Ott, and M. Ittig, "The Oxidation of Parathion
  to Paraoxon, II.  By Use of Ozone," Bull. Environ. Contain. Toxicol.,
  5(l):87-94  (1970).
                                     52

-------
Heath, D. F., "The Effects of Substituents on the Rates of Hydrolysis of
  Some Organophosphorus Compounds.  I.  Rates in Alkaline Solution,"
  J. Chem. Soc.. pp. 3796-3804 (1956).

Heath, D. F., Organophosphorus Poisons. New York:  Pergamon Press (1961).

Joiner, R. L., H. W. Chambers, and K. P. Baetcke, "Toxicity of Parathion
  and Several of Its PhotoaIteration Products to Boll Weevils," Bull.
  Environ. Contain. Toxicol.. 6(3):220-224 (1971).

Joiner, R. L., Piss. Abstr. Int.. 32:4169B (1971/1972).

Koivistoinen, P., and M. Merilainen, "Paper Chromatographic Studies on
  the Effect of Ultraviolet Light on Parathion and Its Derivatives,"
  Acta Agr. Scand.. 12:267-276 (1962).


Lawless, E. W., and T. L. Ferguson (Midwest  Research  Institute), and
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  0142  (January 1972).

Lawless, E. W., T. L. Ferguson, and A. F.  Meiners (Midwest  Research
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  (1973).


Lu, F. C., "lexicological Evaluation of Food Additives and Pesticide
  Residues and Their  'Acceptable Daily Intakes' for Man:   The Role of
  WHO, in Conjunction with FAO," Residue Rev.. 45:81-93 (1973).

Melnikov, N. N., Chemistry of Pesticides. Springer-Verlag, New York,
  pp. 324-329 (1971).

Metcalf, R. L., and R. B. March, "The Isomerization of Organic Thiophos-
  phate Insecticides," J. Econ. Entomol.. 46:288-294 (April 1953).

Mitchell, L. C., "Separation and Detection of Eleven Organophosphate
  Pesticides by Paper Chromatography," J. Assoc. Offie. Agr. Chem., 44:
  643-712  (1961).

Monsanto Company, Agricultural Division, "Parathion and Methyl Parathion,"
  Technical  Bulletin No. AG-lb, St. Louis, Missouri (undated).
                                    53

-------
Mulla, M. S., "Persistence of Mosquito Larvicides in Water," Mosquito
  News. 23(3):234-237  (September 1963).

National Agricultural  Chemicals Association, Safety Guide for Warehousing
  Parathions. Washington, D.C. (1968).

Payton, J., "'Parathion1 and Ultraviolet Light," Nature. 171(4347):355-
  356  (21 February 1953).

The Pesticide Chemical News Guide  (1 May 1974).

Rolston, L. H., and R.  R. Walton, "Parathion Residues in Greens," J. Econ.
  Entomol.. 56:169-172 (1963).

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  (6 January 1953).

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  474  (July 1971).

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  (31 May 1949).

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  Analytical Manual. 2 vols. (1971).

Vernon, C. A., Chem. Soc. (London) Spec. Publ.. 8:17 (1957).

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  189(5):357 (1964).

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  Growth Regulators, Vol. VI; Gas Chromatographic Analysis. Academic
  Press, New York, New York (1972).
                                   54

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               SUBPART II.  B.   PHARMACOLOGY AND TOXICOLOGY
                                 CONTENTS

                                                                         Page

Acute, Subacute and Chronic Toxicity 	  57

  Toxicity to Laboratory Animals 	  57

    Acute Oral Toxicity - Rats	57
    Acute Toxicity - Rats, Routes Other Than Oral	59
    Subacute and Chronic Oral Toxicity - Rats	59
    Toxicity of Parathion in Combination with Other Drugs 	   61
    Acute Oral Toxicity - Mice	63
    Acute Toxicity - Mice, Routes Other Than Oral	65
    Subacute and Chronic Oral Toxicity - Mice	66
    Acute Oral Toxicity - Guinea Pigs	67
    Acute Toxicity - Guinea Pigs, Routes Other Than Oral	67
    Subacute and Chronic Oral Toxicity - Guinea Pigs	67
    Acute, Subacute and Chronic Toxicity - Dogs 	   67
    Acute, Subacute and Chronic Toxicity - Cats 	   68
    Acute, Subacute and Chronic Toxicity - Rabbits 	  68

  Toxicity to Domestic Animals 	  69

    Goats	69
    Sheep	69
    Cattle	70

  Symptomology and Pathology Associated with Mammals	71
  Physiological and Pharmacological Aspects of Parathion	72
  Summary	73

Metabolism of Parathion	75

  Absorption	75
  Distribution 	  76
  Excretion	76
  Bio trans format ion .-.	77
  Degradation of Parathion (and Paraoxon)	79
  Tissue Residues 	   85
  Summary	85
                                     55

-------
                          • CONTENTS (Continued)

                                                                          Page

Effects on Reproduction	85

  Domestic Animals	86
  Wild Avian Species	86

Teratogenic Effects 	  88

  Mammals	88
  Avian - Embryotoxicity	91
  Crustaceans	94

Behavioral Effects 	  95

Toxicity Studies with Tissue Cultures 	  96

Mutagenic Effects 	  98

Oncogenic Effects 	  98

Effects on Humans	100

  Acute and Subacute Toxicity	100
  Symptoms of Parathion Poisoning  	  104
  Dermal Effects 	 105
  Inhalation Effects 	 110
  Occupational Accidental Exposure Hazards 	 Ill

    Field Operations	Ill
    Manufacturing Operations 	 120
    Accidents	121

References	123
                                     56

-------
      This section is concerned with information on the acute,  subacute
and chronic toxicities of parathion in laboratory and domestic  animals.
The metabolism of parathion is reviewed; the absorption, distribution,
excretion, biotransformation, activation and detoxification of  this
compound are discussed.  The effects of parathion on reproduction,
malformation of the young, and behavioral effects are also considered.
Reviews of parathion1s toxic effects on tissue cultures, and  the
promotion or tendencies to bring about mutagenesis and oncogenic effects
are included, although information on these latter effects is quite
limited.  The hazards posed by exposure of humans to parathion  have
been reviewed in relation to acute and subacute toxicity, the symptoms
associated with parathion poisoning, the physiological and pharmacological
action, the routes of exposure (mainly dermal and inhalation),  and the
hazards associated with the use of parathion in field operations and in
manufacturing plants.

Acute, Subacute and Chronic Toxicity

      The information in this subsection is related to the toxicological
studies in laboratory and domestic animals.

Toxicity to Laboratory Animals -

      Acute oral toxicity - rats - Tables 8 and 9 present the findings
of several studies on LD^Q values for parathion administered in rats
by oral, dermal, intraperitoneal, intravenous,  intramuscular means
and by inhalation.  The individual LDcn values  obtained varied from
one study to another.  With only one exception, females were found to
be more sensitive to oral administration of the insecticide than males.
The individual values for reported LDJQ'S in Table 8 were used to
calculate an average LD5Q value.  This average  oral LD^Q was 7.6 mg/kg
(range 2.04 to 30.0 mg/kg) for male rats and 3.5 mg/kg (range 1.75 to
6.0 mg/kg) for females.

      If data in Table 8 are compared to data reported by Gaines (1960)—^t
there is good agreement among researchers on confidence levels for female
rats and relatively good agreement on levels for male rats.   With females
the confidence limits are 3.2 to 4.0 mg/kg, and the average LDr/j is 3.5
mg/kg.  The confidence limits for male rats reported by Gaines are from
10 mg/kg to 17 mg/kg; the computed average from Table 8 is 7.6 mg/kg.
One value (30 mg/kg) in Table 8 was not used in computing the average
because it was thought to lie too far outside the range of the other
values reported.  If the 30 mg/kg LDcg were included in the computation,
the average would then be slightly higher than  9 mg/kg,  and this value
would be very close to the lower confidence limit reported for male
rats by Gaines.
JL/  Gaines, T. G., "The Acute Toxicity of Pesticides to Rats,"
      Toxicol. APP!. Pharmacol.. 2:88-99 (1960).
                                   57

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                              Table 8.  ACUTE ORAL TOKICITT OT PARATHION FOK IATS
    Meaaureswnt
  (•g/kg unless                                                             Weanlings
noted otherwise)           Male            Female           Mixed             (sale)                Reference

    Oral LDso              5.0              1.75              .                .                     ./
    Oral LDjo             13.0              3.60              -                -               b/  e/~ d/  e
    Oral U>50               -               4.03              -                -               ~    £/
    °r«l LD50               -               3.20                               -                     I/
    Oral LD50              3.6               ...                     y
    OralLD50               -                -                -               1.3                    h/
    Oral LD50               -                -               3-6               -                     I/
    Oral LD5o              2.04              -                .                .                     T/
    Oral LD5o               -                -               2.5                                     Jt/
    Oral LDjo              8*6               -                                                       \f
    Oral LDjo              7.0              4.0               -               1.5                    ./
    Oral LDjo              3.6               -                                                       ~f
    Oral LDjo              7.5               ...                     '/
    Oral U>50              5.9              2.70              -               1.75                   T/
    Oral LDjo             12.50             3.JO              -                                      ./
    Oral LDjo             30.00*            3.00              -                                      J/
    Oral LDjo             «.0              6.00              -                                      ^/

    Oral LDjo *            7.6              3.5
    Range                  2.04-30.0        1.75-6.0

 19/20 confidence limits
   (mg/kg)                 10-17             3.2-4.0           -                .                     b/
Lowest dose  to  kill an
   adult  rat

     Oral                 10                3.00              -                                       c/
     Dermal                10                5.00              -                                       cV
 *  Hot included in average calculation.
 a/  Hazleton, L. W., and E. G.  Holland,  "Pharmacology and  Toxicology of Parathlon," Adv. Chem. Series
       Ho. I. 31:31-38 (1950).
 b/  Cslnes, T. B., flft, _fiit- (1960).
 c/  Gainea, T. B., "Acute Toxicity of Pesticides,"  Toxicol.  Appl.  Pharmscol..  14:515-534 (1969).
 d/  Anon., "Toxic Hazards of Pesticides  to Man.   Report of a Study Group," WHO Tech. Rept. Ser..
       114:3-51 (1956).
 e_/  Technical Development Laboratories,  Communicable Dlaeaae Center, Clinical  Memoranda on
       Economic Poisons.  U.S. Department  of Health,  Education, and  Welfare, Public Health Service,
       pp. 7-12 and 17-21 (1 April 1956).
 ll  Delchmann. W. B., W. Pugliese. and J.  Caaaldy.  "Effects  of Dimethyl and Diethyl Paranltro-
       phenyl Thlophosphate on Experimental Animals," AMA Arch. Ind. Hyg. Occup. Med.. 5:44-51 (1952).
 «,/  Edson, E. F., and D. N. Noakes,  "The Comparative Toxlclty of Six Organophosphorus Insecticides
       in the Rat," Toxicol. Appl. Phanaaeol..  2:523-539 (1960).
 h/  Brodeur, J., and K.  P. DuBols, "Comparison of Acute Toxlcity of AntIchollnesterase Insecticides
       to Weanling and Adult Male Rats,"  Proc.  Soc.  Exp. Btol. Med.. 114(2):509-511 (November 1963).
 ll  Edson, E. F., D. M.  Sanderson, and D.  N. Noakes, "Acute  Toxlclty Data for  Pesticides (1964),"
       World Rev. Pest Con.. 4:36-41  (1965).
 i/  Webb, R. E., C. C. Bloomer, and  C. L.  Miranda,  "Effect of Casein Diets on  the Toxlclty of Mala-
       th ion and Parathlon and Their  Oxygen Analogues." Bull.  Environ. Contarn. Toxlcol.. 9(2):102-107 (1973).
 k/  DuBols, K. P., and F. K. Kinoshlta,  "Influence  of Induction of Hepatic Mlcrosomal Enzymes by
       Phenobarbltal on Toxiclty of Organic Phosphate Insecticides," Proc. Soc. Exp. Biol. Med..
       129:699-702 (1968).
 ll  Villeneuve, D. C., and W. E.  J.  Phillips,  "The  Effect  of Acute Ethanol Administration on Parathlon
       Toxiclty and in vitro Parathlon Degradation on the Rat," Can. J. Physiol. Pharmscol.. 49:481-483
       (1971).
 m/  DuBols, K. P., "The  Toxiclty  of  Organophosphorus Compound* to  Mammals," Bulletin of the World Health
       Organization. 44:233-240  (1971).
 n/  Dalloz, J. P., Deiatour, and  G.  Lorgue, "The  Organophosphorus  Pesticides," Rev. Med. Vet.. Toulouse,
       123(10):1356 (1972).
 o/  Jacobaen, P. L., R.  C. Spear, E.  Wei,  "Parathlon and Dlisopropylfluorophosphate (OFF) Toxlclty In
       Partially Hepatectomlzed  Rats," Toxlcol. Appl. Pharaacol.. 26:314-317 (1973).
 £/  Alary,  J-G., and J.  Brodeur,  "Correlation  Between the  Activity of Liver Enzymes and the LDjo of
       Parathlon In the Rat," Can. J.  Physiol.  Pharmacol..  48:829-831 (1970).
 a/  Frawley,  J.  P.,  E. C. Hagan,  and  O.  G.  Fitzhugh, "A Comparative Pharmacological and Toxlcological
       Study of Organic Phosphate-Antlchollnesteraee Compounds," J. Pharmscol. Exp. Thar.. 105:156-165
       (1952).
 r/  DuBols,  K.  P.,  J. Doull, P. R. Salerno, and J.  M.  Coon,  "Studies on the Toxlclty and Mechanism of
~     Action  of  p-Nltrophenyl Diethyl Thlonophosphate  (Parathion)," J. Pharmacol. Exp. Ther.. 95(1):79-91
       (1949).


                                                  58

-------
      Acute toxicity - rats, routes other  than  oral  - The toxicity of
parathion  for rats by exposures other  than oral (Table  9)  has  not been
studied as thoroughly as by oral  toxicity.

      The  intraperitoneal LD5g values  range  from 3.6 to 7.0  mg/kg for
males, and 4 mg/kg was the only value  found  for females.   The  dermal
LD,-0 for rats was about 21 mg/kg  for males with much more variation for
females, 6.8 to 100 mg/kg.  The LD5Q value for  inhalation toxicity has
been reported as 0.0315 mg/liter  (4 hr) and  0.115 mg/liter (1  hr).
Gaines states that ". . .results  and use experience  indicates  that there
is a much  closer relationship between  dermal LDcQ values  and the
occurrence of occupational poisoning than between oral  LD50  values and
occupational poisoning."

      It is interesting that the  values reported for inhalation toxicity
indicate that very low levels of  parathion are  toxic to rats
0.115 mg/liter - 1 hr; and 0.315  mg/liter - 4 hr).

      Subacute and chronic oral toxicity - rats - Only  a  few studies
have been  reported in the open literature on subacute and  chronic
toxicity of parathion in rats.  Barnes and Denz  (1951).!/ and Edson and
Noakes (1960) conducted relatively long-term studies on toxicity.   Under
the Edson  and Noakes study, rats were fed diets containing parathion
for 15 to  16 weeks, at which time survivors were sacrificed,  and
macroscopic examinations were conducted.  Relative organ weights and
measurement of cholinesterase activity in red cells, plasma,  and whole
brain were made.  In this study death due to parathion  toxicity was
reported only in the animals fed at a dietary concentration of 125  ppm,
calculated to be equal to an average parathion intake-of 15.4 mg/kg/day.
Thirty percent mortality (three of 10)  occurred in this group.   No
mortality  occurred in those groups of rats fed at dietary levels of
25 ppm (X  = 2.4 mg/kg/day) or at 5 ppm (X = 0.52 mg/kg/day).
_!/  Barnes, J. M., and F. A. Denz, "The Chronic Toxicity of jx-Nitrophenyl
      Diethyl Thiophosphate (E. 605):  A Long-Term Feeding Experiment
      with Rats." J. Hvg.. 49:430-441 (1951).
                                    59

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          Table  9.  ACUTE TOXICITY OF PARATHION FOR RATS VIA ROUTES
                             OTHER THAN ORAL
Measurement
(rag/kg unless
noted otherwise)
IP U>50
IP LD50
IP LD50
D LD50
D LD50
D LD50
D ID50
LC50 - 1 hr (mg/je)
LC50 - 4 hr (mg/4)

Adults
Male Female Mixed
7.0 4.0
4.5
3.6
21.0 10.9
100.0
50-200
21.0 6.8
0.115
0.0315

Weanlings
(male) Reference
a/
b/
1.5 c/
d/, e/
f/
£/
y
c/
£/

IP LDso - Intraperitoneal injection.
D LDso ~ Dermal exposure.
LCso ~ Lethal concentration by inhalation.
a/  DuBois etal., .op_. _cit. (1949).
b/  Westermann, E., "Accumulation of Environmental Agents or Their Effects
~~     in the Body," Environ. Res.. 2:340-351 (1969).
£/  Kimmerle, G., and D. Lorke, "Toxicology of Insecticidal Organophos-
      phates," Pflanz. Nachr. Bayer, 21:111-142 (1968).
d/  Anon., op. cit. (1956).
e/  Technical Development Laboratories, op. cit. (1956).
    Edson et al., pp. cit. (1960).
f/
£/
h/
    Edson et al., op. cit. (1965).
    Gaines, T. B., op., cit. (1969).
                                    60

-------
      Pertinent findings from the study by Barnes and Denz  (1951) are
incorporated into Table 10.  No food consumption data was obtained in
their study.  Dietary levels of 10 and 20 ppm did not result in any
identifiable symptoms of parathion poisoning.  Subsequent examination
did not reveal any pathological lesions.  A dietary level of 50 ppm
was toxic and treatment at this level resulted in 42% mortality during
the year, with most of the deaths occurring early in the test period
when the animals were young.  At dietary levels of 75 and 100 ppm most
of the rats died during the first few weeks.

      Chronic (dietary) toxicity of parathion fed to rats at several
levels (10,25,50, and 100 ppm in diet) was studied by Hazelton and
Holland (1950).   Their tests were conducted for 104 weeks using male
rats and for 64 weeks using female rats.  With the male rats 40%
mortality was observed for controls over the test period.  Rats fed
parathion in the diet at 50 ppm had a mortality level of 20% and
those treated at a dietary level of 100 ppm had a mortality level of
38%.  In the female rats a relatively high mortality (33%) occurred
in the controls and relatively few rats were included in each treatment
group.  However, a dietary level of 10 ppm parathion did not cause
any mortalities (100% survival), and at 50 ppm the mortality rate
was only about equal to that of the untreated controls (38%).  At
100 ppm, female rats exhibited evidence of toxicity and appeared
unthrifty, indicating that chronic toxicity, like acute toxicity, is
different for female and male rats.

      All females in the control and 10-ppm treatment groups produced
living litters.   All but one female in the 50-ppm treatment group bore
living litters.

      Based on changes in cholinesterase levels, the "no-effect" level
of parathion in the rat was reported by Edson et al., (1964)-i'  to be
0.02 mg/kg/day when the insecticide was fed over an 84-day period.
The smallest effect was found in the range 0.04 to 0.06 mg/kg/day.
These studies indicated that in the rat a wide margin of safety existed
between the maximum "no-effect" level over that needed to evoke a
frank toxic effect.

      Toxicity of parathion in combination with other drugs - The effect
of central-depressant drugs on toxicity of parathion for rats has been
I/  Edson, E. F., et al., "Summaries of Toxicological Data:  No-Effect
      Levels of Three Organophosphates in the Rat, Pig, and Man,"  Food
      Cosmet. Toxicol.. 2:311 (1964).
                                   61

-------
      Table 10.  CHRONIC ORAL TOXICITY TEST IN RATS FED PARATHION^/
Concentration
of parathion
in feed (ppm)

     100
Duration
of test
 (days)

   19
Mortality due to
 poisoning (7.)

      80
      75
      50
   27
  365
      73
      42
      20
       10
  365
  365
         Comments

First death occurred in
  2 hr.  All survivors had
  severe symptoms of poison-
  ing.

Slight symptoms in 2 hr.
  After second week food
  consumption irregular.

First symptoms and first
  death on seventh day.
  Deaths occurred through
  third week but not after.
  Symptoms decreased in
  severity and frequency
  after third month.

Symptomless for entire test
  period.

Symptomless for entire test
  period.
 7/   Adapted  from  the data of Barnes and Denz, OD_. cit.  (1951).
                                     62

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studied by Weiss and Orzel (1967).-'  Following treatment with reserpine,
chlordiazepoxide, hexabarbital and phenobarbital, female rats were treated
with 2, 4, or 8 mg/kg parathion.  The greatest enhancement of toxicity
was obtained at 2 and 4 mg/kg parathion.  Alcohol was found to increase
toxic effects of parathion only at the 4-mg/kg dose level.

     The interactions (toxicity) between polychlorinated biphenyls (PCS)
and parathion in rats was studied by Phillips et al. (1972).V  The
rationale behind the study was that because PCB ingestion can modify
microsomal enzyme activity in rabbits and rats, it is possible that
organophosphate toxicity may also be altered.  Adult female rats were
used in the tests.  Plasma and brain cholinesterase activities were used
to measure the effects of exposure to PCB, parathion and combinations of
the two materials.  The PCB was given orally (in diet) and parathion was
injected intraperitoneally.

     The results of these studies showed that the feeding of PCB (Aroclor
1221) had no effect on plasma cholinesterase.  It was also found that
parathion did not reduce the plasma or brain cholinesterase activity in
animals fed PCB's below that observed in animals which were not fed PCB's.
The conclusion drawn was that chronic ingestion of PCB (Aroclor 1221)
up to a level of 200 ppm in the diet did not potentiate parathion toxicity.
Potentiation of parathion toxicity did not result from feeding of Aroclor
1254 up to 20 ppm.  The effect of Aroclor  1254 when fed at 200 ppm makes
interpretation of parathion toxicity effects difficult.

     Acute oral toxicity - mice - A summary of the data for acute oral
toxicity of parathion to mice is given in Table 11.   The average U>50
value for males was 23.0 mg/kg (range 17.5 to 30.3 mg/kg) and for male-
female groups 12.7 mg/kg (range 6.0 to 25.0 mg/kg).   It appears that
the susceptibility to parathion poisoning for male rats is higher than
for male mice.

     In mice, as with most other species studied, there is no appreci-
able tissue accumulation of residuals, and deaths generally occur only
in cases where parathion is administered as an acute toxic (lethal) dose.
In general, prompt and apparently complete recovery from nonlethal doses
If  Weiss, L. R., and R. A. Orzel, "Enhancement of Toxicity of Anti-
      cholinesterases by Central Depressant Drugs in Rats," Toxicol.
      Appl. Pharmacol., 10:334-339 (1967).
2/  Phillips, W. E. J., G. Hatina, D. C. Villeneuve, and D. L. Grant,
      "Effect of Parathion Administration in Rats Following Long-Term
      Feeding with PCB's," Environ. Physiol. Biochem..  2:165-169 (1972).
                                   63

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       Table 11.  ACUTE ORAL TOXICITY OF PARATHION TO MICE
  Male
                 Acute oral
                             (ing/kg)
                         Female
Mixed
Reference
.
-
-
18.5
-
-
-
-
-
17.5
25.6
30.3
23.0 Average
7.0-30.3 Range
8.1
6.0
25.0
-
21.0
6.4
16.9
6.7
11.6
-
-
-
12.7 Average
6.0-25.0 Range
a/
b/
c/
d/
b/
e/
e/
e/
I/
f/
£/
£/



a/
b/
£/
d/
 /
t
DuBois, K. P., og. cit. (1971).
Hazelton and Holland, op. cit. (1950).
Frawley et al., 03. cit. (1952).
Vukovich, R. A., A. J. Triolo, and J. M. Coon, "The Effect of Chlor-
  promazine on the Toxicity and Biotrans formation of Parathion in
  Mice," J. Pharmacol. Exp. Thera., 178(2) : 395-401 (1971).
Rosival, L., F. V. Selecky, and L. Vbrovsky, "Acute Experimental
  Poisoning with Organophosphorus Insecticides," Bratisl. Lek.
  Listy. 38^:151-160 (1958).
Triolo, A. J., and J. M. Coon, "Toxicologic Interactions of Chlorinated
  Hydrocarbon and Organophosphate Insecticides," J. Agr. Food Chem..
  14(6): 549-555 (1966).
Konst, H., and P. J. Plummer, "Acute and Chronic Toxicity of Para-
  thion to Warm-Blooded Animals," Can. J. Comp. Med. Vet. Sci.,
  14:90-108 (1950).
                               64

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is observed with mice and other laboratory animals.  Animals  that  survive
a single dose longer than 24 hr may generally be expected to  recover  com-
pletely, and there is no apparent residual toxicity  (Hazelton and  Holland,
1950).  However, because depressed blood cholinesterase  lasts throughout
the lifetime of red blood cells, this symptom remains until the red blood
cells are naturally replaced.

     Acute toxicity - mice, routes other than oral - The toxicity  of
parathion by intraperitoneal, intravenous and subcutaneous injection  into
mice is shown in Table 12.  There appears to be close agreement in the
LD50 values for male-female groups injected intraperitoneally and  sub-
cutaneous ly.  There were not sufficient reports found in the  literature
on males and females alone to make a valid comparison of 11)50 values.

     Natoff (1967)—  reported mice to be more susceptible to parathion
administered intravenously than by other routes.  However, in a more
recent study this same author indicated that the intraperitoneal route
was more lethal.  Parathion was shown to be more toxic to female mice by
intraperitoneal injection than by intravenous injection.  The estimated
median lethal dose by oral route was 85.6 uM/kg, by intraperitoneal in-
jection 50.3 uM/kg, by intravenous injection 58 uM/kg, and subcutaneously
71.3 uM/kg.  These values average to about 68 uM/kg for the hepatic routes
and 65 uM/kg for the peripheral routes (Natoff, 1970?-/).

     Subacute and chronic oral toxicity - mice - No information was
found concerning either the subacute or the chronic oral toxicity of
parathion to mice.

     Acute oral toxicity - guinea pigs - The acute oral toxicity of
parathion for guinea pigs as reported by various workers is given in
Table 13.  The LDso value for guinea pigs, male-female groups, varied
from 9.3 mg/kg to 32.0 mg/kg of body weight.   The LDso values for male
guinea pigs were 16.3 mg/kg and 24.0 mg/kg of body weight.
\l  Natoff, I. L., "Influence of the Route of Administration on the
      Toxicity of Some Cholinesterase Inhibitors," J. Phann. Pharmacol..
      19^:612-616 (1967).
2_/  Natoff, I. L., "Influence of the Route of Exposure on the Acute
      Toxicity of Cholinesterase Inhibitors," Europ. J. Toxicol.,
      3:363-367 (1970).
                                   65

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  Table 12.   ACUTE TOXICITY OF PARATHION TO MICE--ROUTES OTHER THAN ORAL


Routed/ Male
IP 10
13.5
-
-
ID50 (mg/kg)
Female Mixed
10
-
14.7
8.2

Reference
b/
c/
d/
e/
IV
7.6
            16.9
                                          9.0 Average
                                          4.6-14.4 Range
                          5.4
                          1.0
                                                               f/
                                                               d/
                                                               e/
                                                               e/
SC
            20.8
                                         11.0 Average
                                          7.8-13.6 Range
                                                               d/
                                                               £/
                                                               e/
                                                               J/
a/  IP - Intraperitoneal; IV - Intravenous; SC - Subcutaneous.
b/  DuBois et al., OJL. cit. (1949).
c/  Benke, G. M., K. L. Cheever, F. E. Mirer, and S. D. Murphy,  "Com-
      parative Toxicity, Anticholinesterase Action and Metabolism of
      Methyl Parathion in Sunfish and Mice," Toxicol. Appl. Phannacol..
      28j97-109 (1974).
d/  Natoff, I. L., 0£. cit. (1967).
e/  Rosival et al., 02. cit. (1958).
f/  Vukovich et al., oj.. ^it. (1971).
                                  66

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       Acute toxicity - guinea pigs, routes other than oral - The dermal
 LD   for parathion in guinea pigs is reported as 0.60 ml/kg on intact
 skifl and 0.80 ml/kg on  abraded skin (Roudabush et al., 1965±').  The
 LD50 for intraperitoneal injection is 12.0 mg/kg (Anon., Council of
 Europe, 19642-').

       Subacute and chronic oral toxicity - guinea pigs - No subacute or
 chronic oral toxicity data for guinea pigs were found relative to
 parathion.

      Acute,  subaeute  and  chronic  toxicitv  -  dogs -  It  has  been  reported
 (Anon.,  Council of  Europe,  1964) that acute oral toxicity of  parathion
 in dogs  is 3.0  to 5.0  mg/kg.  The  intraperitoneal LD5Q  values for  dogs
 is 3 to  5  mg/kg of  body weight  (DuBois et al.,  1949); 12 to 20 mg/kg
 (Anon.,  Council of  Europe,  1964).   By intravenous injection,  the lethal
 dose is  12 to 20 mg/kg (Anon.,  Council of Europe, 1964).
        Table  13.  ACUTE ORAL  TOXICITY OF PARATHION TO GUINEA PIGS


Sex
Male and female
Male and female
Male and female
Male and female
Male
Male
LD50
(mg/kg)
9.3
16.2
19.8
32.0
24.0
16.3

Reference
a/
b/
b/
c/
b/
b/


a/  Hazelton and Holland, op. cit. (1950).
b/  Konst and Plummer, op. cit. (1950).
c/  Frawley et al., op., cit. (1952).
I/  Roudabush, R. L., C. J. Terhaar, D. W. Fassett, and S. P. Dziuba,
      "Comparative Acute Effects of Some Chemicals on the Skin of Rabbits
      and Guinea Pigs," Toxicol. Appl. Pharmacol.. 7:559-565 (1965).
2/  Anon., Council of Europe-Netherlands Report on Parathion and Parathion-
      Methyl, Ministerie von Sociale Zahen En Volksgezandheid (1964).
                                    67

-------
     The subacute toxicity of parathion for dogs was studied by Frawley
and Fuyat (1957)!' by measuring changes in plasma and RBC cholinesterase.
When parathion was incorporated in the dogs' diet at 1 ppm and fed for
24 weeks, a significant  (minimal) reduction in plasma cholinesterase
occurred.  At 2 and 5 ppm plasma cholinesterase reductions of 60 and 70%
were recorded.  Inhibition of RBC cholinesterase occurred where diet
levels of parathion were 2 ppm or above.

     Chronic (dietary) toxicity of parathion for dogs was determined by
Hazelton and Holland (1950) using 15% wettable powder given in gelatin
capsules 6 days/week for 90 days.  The capsules were given either with
a meal or immediately afterward (prior administration resulted in loss of
appetite and food refusal).

     At 2 mg/kg/day the dog lived 3 weeks but exhibited toxic signs con-
tinuously.  At 1 and 3 mg/kg/day the animals survived for the full 90-
day test period.  During the early stages the dogs were nervous and ir-
ritable but during the final month both dogs were normal in their behavior.
Neither dog showed evidence of gross pathology.  Histopathological examina-
tion revealed some degenerative changes in the liver.

     Acute, subacute and chronic toxicity - cats - No data were found in
the open literature on the acute, subacute and chronic oral toxicity of
parathion to cats.  The subcutaneous, intraperitoneal and intravenous
LDso's are 15.0 mg/kg, 3.0 to 5.0 mg/kg and 3.0 to 5.0 mg/kg, respectively
(Anon., Council of Europe, 1964).  DuBois et al. (1949) reported an
intraperitoneal 11)50 value of 12 to 20 mg/kg of body weight.

     In cats, parathion has been shown to be readily absorbed through
the skin in unchanged form, although no dermal 11)50 values have been re-
ported (Fredriksson, 1964^').

     Acute, subacute and chronic toxicity - rabbits - The acute oral LD50
for male rabbits is 68 mg/kg of body weight as reported by Konst and
Plummer (1950) .
\l  Frawley, J. P., and H. N. Fuyat, "Effect of Low Dietary Levels of
      Parathion and Systox on Blood Cholinesterase of Dogs," J. Agr. Food
      Chem., 5:346 (1957).
2/  Fredriksson, T., "Studies on the Percutaneous Absorption of Para-
      thion and Paraoxon.  Part VI.  In vivo Decomposition of Paraoxon
      During the Epidermal Passage," J. Invest. Dermato1.. 42:37-40 (1964)
                                   68

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       The acute dermal LD5Q for mixed sexes of rabbits is 0.07 ml/kg
 (Roudabush et al., 1965).  Diechmann et al (1952)i/ reported the
 dermal LD50 of parathion for rabbits is 870 mg/kg, which was similar
 to his findings on guinea pigs.  Lehman (1948), on the other hand,
 reported the acute dermal LD   for rabbits to be 40-50 mg/kg.  In
 rabbits, it has been shown tftQt parathion is absorbed dermally in an
 unchanged form (Fredriksson et al., 1961-/.

       No information was found concerning subacute or chronic studies
 in rabbits.

Toxicity to Domestic Animals -

     Goats - Of the ruminants which have been studied,  the  goat  appears
most susceptible to parathion poisoning.  Although no LD5Q  values  have
been reported for this animal, daily subacute oral doses  as  low  as 8 rag/
kg were reported to have killed one experimental goat in  11  days.   Other
subacute doses reported for goats range from 12 mg/kg for 5  days  to
32 mg/kg for 10 days (Wilber and Morrison, 1955-2').  Unlike  other  ruminant
species studied, parathion is reported to cross the placenta1 blood bar-
rier and exert anticholinesterase effects on the fetus.   Parathion has
been reported to appear in the milk of lactating female goats.   It is
not known how long the anticholinesterase activity of milk  from  poisoned
goats persists (Wilber and Morrison, 1955).

     Sheep - The acute oral U>50 of parathion for ewe and ram lambs is
estimated at 40 to 50 mg active ingredient per kilogram of body weight.
Lethal doses for lambs range from four doses of 24 mg/kg  each to three
doses of 48 mg/kg each.  The insecticide was not markedly cumulative in
its toxic effects (Mol et al., 1972.V).  Sheep receiving  daily subacute
doses exhibit symptoms similar to those in acutely affected  animals.
Affected sheep that survived recovered completely after cessation  of
treatment, and appeared to be normal with no recurring ill effects.
\J  Diechmann, W. B., W. Pugliese, and J.  Cassidy,  "Effects of Dimethyl
       and Diethyl Paranitrophenyl Thiophosphate on Experimental Animals,"
       AMA Arch. Ind. Hyg. Occup.  Med.. 5:44-51 (1952).
2/  Fredriksson, T., W. L. Farrior, Jr., and R. F.  Witter,  "Studies on
       the Percutaneous Absorption of Parathion and Paraoxon.   Part I.
       Hydrolysis and Metabolism Within the Skin,"  Acta Derm.  Venerol..
       41:335-343 (1961).
J3/  Wilber, C. G., and R. A. Morrison, "The Physiological Action of
       Parathion in Goats," Am. J. Vet. Res., 10(59):308-313 (1955).
4/  Mol, J. C. M., D. L. Harrison, and R.  H. Tlefer, "Parathion:
       Toxicity to Sheep and Persistence on Pasture and in  Soil,"  N. Z.
       J. Agr. Res.. 15:306-320 (1972).

                                    69

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      The maximum safe oral dose (MSD)  for sheep has  been determined  to
 be 10 mg/kg,  whereas  the minimum toxic dose (MTD)  is 20 mg/kg (Radeleff
 et al.,  1955i/).

      Data obtained from grazing studies (Mol et al., 1972)  indicate  that
 sheep may be  grazed,  with no ill effects, on pastures following heavy
 spraying with parathion.  In this study pastures were sprayed with up to
 6.0 Ib/acre (approximately seven to 27 times normal  application rate).
 Sheep were grazed on  plots for 28-day periods beginning at  0 to 30 days
 after spraying.   In the most severe case (28 days  grazing immediately
 following spraying),  sheep developed no symptoms of  poisoning except
 slight scouring, even when their blood cholinesterase was almost  com-
 pletely inactivated.
                                21
      Cattle - Dahm et al (1950)— fed two groups  of lactating cattle 1 ppm
 and  5 ppm of  parathion for 81  days.  The parathion was  given by capsule.
 These levels  provided 0.022 and 0.112  mg/kg/day, and they produced no
 noticeable adverse effects.  Two other cows  were fed 5  ppm of parathion
 the  first week.   The  amount was increased each week  until 40 ppm was
 being consumed per week.   The  lowest and highest levels  were equivalent
 to 0.11  and 0.89 mg/kg/day.  No adverse effects  were observed.

      The MSD  and MTD  for 1- to  2-week old calves  have been conservatively
 estimated to  be  0.25  and 0.5 mg/kg, respectively, whereas the MSD for
 year-old cattle  is 4.0 mg/kg (Radeleff et al..  1955).  A more thorough
 study carried out by  Fankaskie et al.  (1952)-'  indicates that the above
 estimates may be low.   Cattle  were fed a ration containing baled alfalfa
 hay  for  a 61-day period.   The  average  parathion concentration of all hay
 fed  over the  61-day period was  13.6 ppm.   During this period no parathion
 residues or degradation products  could be detected in the urine, milk,
 or jugular blood of the  test animals.   In an additional  experiment a cow
\l  Radeleff, R. D., G. T. Woodard, W. J. Nickerson, and R. C. Bushland,
      "Part II.  Organic Phosphorus Insecticides," The Acute Toxicity of
      Chlorinated Hydrocarbon and Organic Phosphorus Insecticides to Live-
      stock, U.S. Department of Agriculture, Tech.  Bull.  1122,  pp. 35-46  (1955),
2/  Dahm, P. A., F. C. Fountaine, J. C. Pankaskie, R. C. Smith, and F. W.
      Atkeson, "The Effects of Feeding Parathion to Dairy Cows," J^
      Dairy Sci.. 33(101):747-757 (1950).
J3/  Pankaskie, J. E., F. C. Fountaine, and  P. A. Dahm, "The Degradation
      and Detoxification of Parathion in Dairy Cows," J. Econ. Entomol.,
      45:51-60 (1952).
                                    70

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was fed par a th ion by direct oral administration of daily initial doses
of 1 mg/kg for 14 weeks.  The dosage was increased weekly until the daily
dose reached 32 mg/kg of body weight.  The authors stated that this level
was the highest intake by any survivors.  During this time, no symptoms
of parathion poisoning appeared.  To rule out development of  tolerance
over the 14-week feeding period, another cow was fed 16 mg/kg/day for  1
week without adverse effects.  As with the alfalfa feeding experiments,
no residues of parathion or £-nitrophenol were detected in urine,
jugular blood or milk.  These experiments indicate that adult dairy
cattle are less susceptible to parathion poisoning  than  other ruminants.

     Radeleff and Bush land (I960)—  in a symposium on "The Nature and
Fate of Chemicals Applied to Soils, Plants and Animals" reiterated an
observation made earlier in some of their toxicological studies:  with
toxic chemicals that were not of equal toxicity to adult and  young animals
the dairy calf is the most susceptible of all farm animals (Radeleff  and
Bushland, I960).

     The minimum toxic dose of parathion (used as a dip or spray) for
1- to 2-week old calves was reported as 0.01% while that for sheep and
goats (adults) was 1.0%.

     Additional evidence for the greater sensitivity of calves to para-
thion (compared to steers and sheep) was reported by Radeleff and Woodard
(1957)=/ and Radeleff (1958);!/  A lethal dose of parathion for calves
was reported to be 1.5 mg/kg while a lethal dose for steers and sheep
was 75 and 20 mg/kg, respectively.  Twenty-five milligrams per kilograms
was reported to be nontoxic for steers, 10 mg/kg was nontoxic for sheep
but the nontoxic dose for calves was 0.25 mg/kg.

Symptomatology and Pathology Associated with Mammals - While  the symptoms
may vary in intensity with dosage, mammals can be expected to exhibit
those symptoms typical of cholinergic poisoning.  Among these symptoms
are muscle faciculation, excessive salivation, tremor, miosis, partial
paralysis, labored breathing, lachrymation, diarrhea, involuntary
I/  Radeleff, R. D., and R. C. Bushland,  "The Toxicity of  Pesticides  for
      Livestock," Symposium:  The Nature  and Fate of  Chemicals  Applied
      to Soils, Plants, and Animals," Agricultural Research Service,
      U.S. Department of Agriculture (27-29 April 1960).
2J  Radeleff, R. D., and G. T. Woodard, "The Toxicity of Organic Phos-
      phorus Insecticides to Livestock,"  J. Am.  Vet.  Med.  Assoc., 130:
      215-216 (1957).
3J  Radeleff, R. D., "The Toxicity of Insecticides and Herbicides to
      Livestock." Adv. Vet. Sci.. 4:265-276 (1958).
                                   71

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urination, convulsion, depression and death  (Hazelton and Holland, 1950;
Gaines, 1960; Konst and Plummer, 1950).

     In acute poisonings autopsy findings usually reveal only gastroin-
testinal irritation and pulmonary hemorrhage.

     In rats fed at relatively high dietary  levels of parathion for long
periods of time, the symptoms reported are those of acute poisoning
(salivation, lachrymation, intestinal hyperperistalsis and muscular
tremors) occurring as recurrent episodes.

     Pathologically, chronically poisoned animals show the same lesions
as those acutely poisoned--vacuolation and collapse of the acinar structure
of the submaxillary gland and pancreas along with atrophy of the thymus
and spleen (Barnes and Denz, 1951).  These symptoms are most prominent
during the early exposure period and may diminish with continued feeding.

Physiological and Pharmacological Aspects of Parathion - The physiology,
pharmacology and toxicology of parathion poisoning have been described
by Hamblin and Golz (1955).—'  These authors state that the only im-
portant pharmacological action of parathion  is  its inhibiting action on
the enzyme acetylcholinesterase.

     Acetylcholine is needed for nerve impulse  transmission, and this need
is met by the action of the enzyme choline acetylase.  The hydrolysis of
acetylcholine to choline and acetic acid is  accomplished by another enzyme,
acetylcholinesterase.  There are two types of cholinesterases, true and
pseudocholinesterases.  The former is found  in  nerve and muscle tissue
and in the erythrocytes.  Pseudocholinesterase  is actually a group of
enzymes which are found in the pancreas and  salivary glands and other
tissues.  The latter enzymes hydrolyze acetylcholine more slowly than
acetylcholinesterase.

     The plasma cholinesterase in most species, including man, is pseudo-
cholinesterase.  The concentration varies widely from individual to in-
dividual, and human erythrocytes contain true cholinesterase.

     The absorption of parathion brings about the accumulation of acetyl-
choline, because of a failure in the disposal mechanism in parasympa-
thetic post-gang1ionic fibers, in sympathetic ganglia and in the central
nervous system as well as at the myoneural junction of muscle.
II  Hamblin, D. 0., and H. H. Golz, "Parathion Poisoning, A Brief Re-
      view," Ind. Med. Surg.. 24(22)-.65-72 (1955).
                                    72

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     Autopsy examination of animals  succumbing to lethal dosages of para-
thion, in either single or multiple  doses, has not revealed extensive
or wide-spread tissue damage that could be related to treatment with the
compound.

      The only accumulative aspects  of parathion are suggested by the
acetylcholine recovery period being  contingent upon the death of the red
blood cell.  Furthermore,  the inhibition of the enzyme is not reversible.
Repeated doses of parathion will produce steadily decreasing levels of
enzyme activity in the blood.

      In the diagnosis of  parathion  poisoning, the RBC cholinesterase
level is one of the more important clinical measurements.  Plasma
cholinesterase is nonspecific  and it has  no functional relationship
with the activity of the nervous system.   Exposure to anti CHE agents
is assumed when the plasma and RBC cholinesterase activity is depressed
by 25%.  The excretion of  p-nitrophend in the urine confirms this
assumption.

      In acute poisoning,  manifestations  usually  occur only after more
than 50% of the plasma cholinesterase is  inhibited.  After an acute
poisoning, it takes about  4 weeks for plasma  cholinesterase to return
to normal.
Summary - Parathion is a highly toxic pesticide, as evidenced by studies
with laboratory and domestic animals, fish, other aquatic life, avian
species, wildlife and humans.  The oral LD50 value for rats is about
7 rag/kg (range 2 to 30 mg/kg) for males and 4.0 rag/kg (range 2 to 6 rag/
kg) for females.  The LC5Q value for inhalation toxicity has been re-
ported as 0.0315 mg/liter (4-hr exposure) to 0.115 mg/liter (1-hr ex-
posure).  The LDso value for intraperitoneal injection ranges from 3.6
to 7.0 mg/kg.  Dermal toxicity is much less pronounced than the other
toxicity measurements, ranging from 6.8 to 200 mg/kg; most of the re-
ported results were above 20 mg/kg.

     No mortality occurred when rats were fed parathion for 15 to 16
weeks at 0.52 mg/kg/day or at 2.4 mg/kg/day.  The mortality went up to
30% when the average daily dosage was increased to 15.4 mg/kg.  Over a
1-year period the mortality was 42% for rats fed 50 ppm of parathion.
The mortality rose to 80% over a 19-day feeding period with a concen-
tration of parathion in the feed equal to 100 ppm.

     Mice are not as susceptible to parathion poisoning as rats.  The
average LDso for males was 19.8 mg/kg (range 7.0 to 30.3 mg/kg) and for
male-female groups, 12.7 mg/kg (range 6.0 to 25.0 mg/kg).
                                    73

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      The intraperitoneal and intravenous U^Q values for mice were not
as low as for rats*  In general, the order of toxicity for mice was
about the same for the intraperitoneal and intravenous routes. Sub-
cutaneous injections yielded high LD5Q values (7.8 to 21.4 mg/kg).

      No information was found on long-term feeding studies with mice.
Only one paper reported a dermal toxicity of 0.60 ml/kg (intact skin)
and  0.80 ml/kg (abraded skin).

      The oral toxicity of parathion for guinea pigs was close to mice
(LD5Q range 9.3 mg/kg to 32.0 mg/kg).  The LDr« value for intraperitoneal
injection was 12.0 mg/kg.

      No information was found for the subacute and chronic oral toxicity
of parathion to guinea pigs.

      The information on the toxicity of parathion in dogs was sparse.
One report on acute oral toxicity indicated that 3.0 to 5.0 mg/kg was
lethal.  Two reports on the intraperitoneal LDc0 value were at variance—
12 to 20 mg/kg and 3 to 5 mg/kg.

      The subcutaneous, intraperitoneal and intravenous LDcQ values are
15.0 mg/kg, 3.0 to 5.0 mg/kg and 3.0 to 5.0 mg/kg, respectively, for cats.
Another report indicated that the intraperitoneal U^Q for parathion in
cats was 12 to 20 mg/kg.  No dermal toxicity data is available.  No
information was found on subacute and chronic oral toxicity to cats.

      One report was found for the LD50 (68 mg/kg) for oral ingestion by
rabbits.  The acute dermal LD5Q appears to be about 0.07 mg/kg (abraded
skin).

      There was one report on the toxicity of parathion to goats.  No
LD50 values were reported.  Daily doses of 8 mg/kg killed one animal
in 11 days.

      The maximum safe oral dose for sheep has been determined to be 10
mg/kg and the minimum toxic dose as 20 mg/kg.  One investigator reported
that the acute oral LDcn of parathion for lambs was estimated to be 45
to 50 mg/kg.

      Parathion has been fed to cattle at 1 ppm and 5 ppm/day for 81 days
without any noticeable effect.  One dairy cow has been fed 32 mg/kg/day
for 7 days without adverse effects.  The same animal had been fed for a
number of weeks at lower gradually increasing levels.
                                   74

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     These collective data Indicate that parathion is highly toxic to
all species tested thus far by all routes.  There is usually a lesser
degree of toxicity produced by dermal exposure than by other routes.
The vehicle is very important in dermal toxicity tests.  Episodes of
acute toxicity are more likely to occur in nature than are chronic
poisonings.  The pathology of chronic toxicity is similar to that
found in acute episodes.  The young are more susceptible than
the mature organisms.  There is a unique sex aspect in some species
(male rats are less susceptible than females, whereas in most other
species sex differences are not as great).  The symptoms and mechan-
isms of physiological action in all species are essentially the same.
Cholinesterase depression is a sensitive clinical measurement and in
some instances too sensitive (chronic exposures).  The pathological
damage appears to be minimal even in chronic exposures.

Metabolism of Parathion

     The metabolism of parathion is discussed in the following seven
subsections:  absorption, distribution,  excretion, biotransformation,
degradation, tissue residues, and summary.

Absorption - Parathion is absorbed in animals by the oral,  inhalation
or dermal routes.  Nabb et al.   (1966) 1'  have shown that parathion
was absorbed through rabbit skin at the  rate of 0.059 ug/min/cm2 based
on the inhibition of red cell acetylcholinesterase activity.
Fredriksson (1964) measured the rate of  absorption of ^2p-paraoxon
through cat skin.  When 50 ul of paraoxon was applied to 4.1 cm2 of
skin the absorption rate was found to be about 6 muM/min/cm .   Blood
levels 3 hr later were 0.05 ug of paraoxon per milliliter.   However,
approximately 90% of the paraoxon was detoxified during epidermal
passage due to a skin enxyme in cats that can split the paraoxon
molecule.  In a previous study, Fredrikson (1961b) also reported the
rate of paraoxon absorption to be 0.47 to 0.95 muM/min/cm  through
cat skin.

     Parathion was 10 times less toxic than paraoxon when given
intravenously but was 55 times less toxic when applied to the skin
of rabbits (Nabb et al., 1966).
I/  Nabb, D. P., W. J. Stein, and W.  J.  Hayes,  Jr.,  "Rate of Skin
    Absorption of Parathion and Paraoxon," Arch.  Environ. Health,
    12:501-505 (1966).

2J  Fredriksson, T., "Studies on the  Percutaneous Absorption of Para-
    thion and Paraoxon.  Part III. Rate of Absorption of Parathion,V
    Acta Derm. Venerol.. 41:353-363 (1961b).
                                     75

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     A comparative study of the acute dermal toxicity and primary irrita-
tion in rabbits and guinea pigs indicated that parathion was more toxic
to rabbits  (Roudabush et al.,  1965).
Distribution - The dermal and intravenous administration of
to rabbits showed very little accumulation of 35g in the blood, organs
or tissues (dermal 10 days after exposure; intravenous 1 hr after ex-
posure)  (Jensen et al., 19521').  Feeding 167 mg of parathion in baled
hay  to cows did not produce detectable  levels of parathion or £-nitro-
phenol in milk or blood (Pankaskie  et al., 1952).  In the same study cows
were fed 1 to 32 mg/kg/day of parathion by capsule, and did not produce
detectable levels of parathion, £-nitrophenol °* £-aminophenol in the
milk or  blood.  Giachetti et al. (1966).?-/ measured the amount of paraoxon
in rat brain after treatment with  1 mg/kg of parathion by intraperitoneal
injection.  At 6 hr after treatment there was 30  to 33 ng of paraoxon,
2 to 3 ng after  18 hr and only  a trace  at the end of 72 hr.  Taylor and
Gaut (1968).3-' have written a review describing  the distribution and bind-
ing  of parathion and paraoxon at the enzyme  level in many tissues.

Excretion - Cows fed parathion  excreted aminoparathion, diethylphosphoric
acid, and phosphorothioic acid  in  the urine  and about 17. of the dose in
the  milk (Ahmed et al., 19584-/) .   Cows  probably also hydrolyze parathion
to £-aminophenol and excrete £-aminophenol glucuronide  (Pankaskie et al.,
1952; Ahmed et al., 1958).  Andersen and Karlog (1963)!/ found from in
vitro experiments with fluid that  75 to 907.  of  the parathion is reduced
to aminoparathion or intermediates  after  10  min; conjugated £-aminophenol
was  the  dominant metabolite found  in the urine. Cook (1957)j>/ had re-
ported earlier that the reduction  of parathion  to £- aminoparathion was
almost complete in 1 hr.
 \J   Jensen,  J.  A., W.  F.  Durham,  and G.  W.  Pearce,  "Studies  on Fate  of
       Parathion in Rabbits,  Using Radioactive Isotope Techniques," AMA
       Arch.  Ind.  Hyg.  Occup. Med.. 6:326-331 (1952).
 2/   Giachetti,  A., C.  Grasso, and G. Bernardi, "Persistence  of 0,0-Diethyl-
       0-para-nitrophenyl  phosphate (Paraoxon) in the  Brain of  the White
       Rat Treated with a  Single,  Subtoxic Dose of Parathion,"  Ric. Sci.,
       36(10):1077 (1966).
 3/   Taylor,  W.  J., and Z. N. Gaut, "Poisoning with  the Newer Organophos-
       phorus Insecticides,"  Int.  J. Clin. Pharmacol.. 1(3):175-183  (1968).
 4/   Ahmed, M. K., J. E. Casida, and R. E. Nichols,  "Bovine Metabolism of
       Organophosphorus Insecticides: Significance  of Rumen  Fluid with
       Particular Reference to Parathion," J. Agr.  Food Chem.. 6:740-746
       (1958).
J>/   Andersen, A.  A., and  0.  Karlog, "Elimination of Parathion  in Cows
       After  Oral and Dermal  Administration," Acta Vet. Scand.. 4:156-169
       (1963).
 6/   Cook,  J. W.,  "In vitro Destruction of Home Organophosphates Pesticides
"~      by  Bovine Rumen  Fluid," J.  Agr. Food  Chem.. 5(11):859-863 (1957).
                                   76

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     Rats treated with 35S-parathion excreted 35S-sulfate in the urine
(Nakatsugawa et al., 1969I/).   Paranitrophenol has been shown to be ex-
creted in the urine of monkeys (Lieben et al., 1952-^), and man (Wolfe
et al., 1970;!/ Roan et al., 1969^7) following exposure to parathion.

Biotransformatton - The biotransformation of parathion involves two dis-
tinct  phenomena, activation and deactivation  (detoxification).

     Gage  (1953)^  found paraoxon in a liver extract of parathion-treated
rats.  Aldridge  (1953)6-/ found that the serum cholinesterase enzymes of
rabbit, rat and horse have different substrate specificities and demon-
strated an enzyme which hydrolyzed parathion.  Ecobichon et al. (1963)2.'
reported  that human liver esterases were inhibited by compounds, includ-
ing  parathion, which require activation.  Gaines et al. (1966)£' found
that rats  infused with 1.41 mg/kg of parathion via the intestinal vein
died.  However,  if  1.69 mg/kg of parathion was infused via the femoral
vein,  none died within 65 min.  Thus, it seemed that passage through
the  liver increased parathion toxicity.  Shishido and Fukami (1963)9/
 I/  Nakatsugawa, T., N. M. Tolaman, and P. A. Dahm, "Degradation of Para-
 "     thion in the Rat," Biochem. Pharmacol.. 18(5):1103-1114 (1969).
 2J  Lieben,  J., R. K. Waldman, and L. Krause, "Urinary Excretion of Para-
       nitrophenol Following Parathion Exposure," AMA Arch. Ind. Hyg.
       Occup. Med.. 6:491-495 (1952).
 $/  Wolfe,  H.  R., W. F. Durham, and J. F. Armstrong, "Urinary Excretion
 "~     on Insecticide Metabolites," Arch. Environ. Health. 21:711-716 (1970).
 4/  Roan, C. C., D. P. Morgan, N. Cook, and E. H. Paschal, "Blood Cho lines-
       terases, Serum Parathion Concentrates and Urine jj-Nitrophenol Con-
       centrations in Exposed Individuals," Bull. Environ. Contarn. Toxicol.,
       4(6):362-369 (1969).
 5/  Gage, J. C., "A Cholinesterase Inhibitor Derived from 0,0-Diethyl
 ~     0-£-Nitrophenyl Thiophosphate in vivo," Biochem. J.. 54:426-430 (1953),
 6_/  Aldridge,  W. N., "Serum Esterases, 2.  An Enzyme Hydrolysing Diethyl
       E-Nitrophenyl Phosphate (E600) and Its Identity With the A-Esterase
       of Mammalian Sera," Biochem. J.. 53:117-124 (1953).
 7/  Ecobichon, D. J., and W. Kalow, "Action of Organophosphorus Compounds
 ~~     Upon  Esterases of Human Liver," Can. J. Biochem. Physiol.. 41:1537-
       1546  (1963).
 8/  Gaines, T. B., W. J. Hayes, Jr., and R. E. Linder, "Liver Metabolism
       of Anticholinesterase Compounds in Live Rats:  Relation to Toxicity,"
       Nature,  .209(5018):88-89 (1966).
 9/  Shishido,  T., and J. Fukami, "Studies on the Selective Toxicities of
 ~     Organic  Phosphorus Insecticides (II) ," Botyu-Kagaku. 28(1) : 69-76
       (February 1963).
                                    77

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reported that  liver and kidney slices converted parathion to paraoxon.
They also reported that the microsomal fraction and the microsomal super-
natant solutions were active  in this conversion.  Both fractions required
diphosphopyridine nucleotide  (NAD) as a cofactor for this conversion.

     Nakatsugawa and Dahm  (1967)—' used ^S-parathion to demonstrate that
  S was bound  to liver microsomes (probably by a desulfuration reaction).
Activation by  microsomes required NADPH2  and Q£.  The reaction was in-
hibited by SKF-525A and other synergists.
                           2 /
     Nevkovic  et al. (1973)-' demonstrated that both NADH2- and NADPH2-
 linked electron transport  components were involved  in the oxidative
metabolism of  parathion and  that  the activity of NADH2- cytochrome c
reductase was  significantly  higher  than NADPH2 - cytochrome c reductase.
                           o /
     Orzel and Weiss  (1966)—' used  rat brain acetylcholinesterase in-
hibition as  a  measure of the conversion of parathion to paraoxon.  Enzyme
inhibition was decreased by  oral  administration of  y-aminobutyric acid,
but not by intrathecal administration.  Inhibition  of enzyme activity
was increased  by pretreatment with chloroform and isonicotinic hydrazide,
a monoamine  oxidase inhibitor.  Pretreatment with SKF-525A (a microsome
inhibitor),  arsenite (an oxidative enzyme inhibitor) or pyrogallol (a
transferase  inhibitor) did not alter the  enzyme inhibition.  Hitchcock
and Murphy (1967a)-' studied  parathion metabolism in liver and kidney
homogenates  from rats and  chickens.  Kidney homogenates were half as
active as liver homogenates  based on the  conversion of parathion to para-
oxon.  Liver required NADP and glucose-6-phosphate  for maximal activity.

     In 1969,  Nakatsugawa  et al.  (1969) confirmed the initial in vivo
conversion of  parathion to paraoxon in male rats using "s and
"I/  Nakatsugawa,  T.,  and  P. A. Dahm,  "Microsomal Metabolism of Parathion,"
      Biochetn.  Pharmacol..  16(l):25-38  (1967).
2/  Nevkovic, N., S.  Vitorovic,  and M.  Plesnicar, "The Role of Liver
      Microsomal Enzymes  in the  Metabolism of Parathion," Biochem.
      Pharmacol., 22:2943-2946 (1973).
3/  Orzel, R. A., and L.  R. Weiss, "The Effect of Various Chemicals on
      Rat Brain Cholinesterase Inhibition  by Parathion," Arch. Int.
      Pharmacodyn. Ther.. 164(1):150-157 (1966).
^/  Hitchcock,  M., and S. D. Murphy,  "Activation of Parathion and Guthion
      by Tissues of Mammalian, Avian, and  Piscine Species," Fed. Proc.,
      26(2):427 (1967a).
                                    78

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Davison (1955)—  found that the in vitro conversion of parathion was in-
hibited 527. by 10'3 M SKF-525A; 100% by iodoacetate, chloropicrin and
2,4-dinitrophenol; 90% inhibited by HgCl2, hydroxylamine and choline;
66% inhibited by £-chloromercuribenzoate and not inhibited by cyanide.
He also found that NAD and magnesium ions were required cofactors.  Cyto-
chrome c was not necessary for metabolism.
                              o/
     Fukuto and Metcalf (1969)—  reviewed eight general reactions of the
mixed function oxidate system, including the desulfuration of the phos-
phorothionates.  One of the reactions is primarily associated with the
conversion of parathion to paraoxon:
            Mixed Function
               Oxidase
                  +     - >    (RO)3P=S - » (RO)3P=0
               NADPHo                       „   ,_    ,  .
                    *                       (desulfuration)
Degradation of Parathion (and Paraoxon) -  In 1958 Ahmed et al. demon-
strated that rumen fluid from cows converted parathion to aminopara-
thion, and suggested that it was excreted as a glucuronide conjugate.
Later, Williams (1970)—' measured (3-glucuronidase in rats after daily
doses of 0.25, 0.5 and 1.0 mg/kg parathion for 4, 10 or 15 days.  In
females the serum p-glucuronidase was elevated in all cases.  In males
the p-glucuronidase was elevated only after 15 days of treatment.  There
was a decrease in serum 0-glucuronidase in both sexes which was not dose-
related .
I/  Davison, A. N., "The Conversion of Schradan  (OMPA) and Parathion
      into Inhibitors of Cholinesterase by Mammalian Liver," Biochem.
      J,.., 61:203-209 (1955).
2_/  Fukuto, T. R., and R. L. Metcalf, "Metabolism of Insecticides  in
      Plants and Animals," Ann. N.Y. Acad. Sci..  160:97-113  (1969).
3_/  Williams, C. H., "g-Glucuronidase Activity in the Serum  and Liver
      of Rats Treated with Parathion," Toxicol.  Appl. Pharmacol.,  16:533-
      539 (1970).
                                   79

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     Matsumura and Ward  (1966)—' found  that human  liver degraded para-
thion slightly faster  than rat  liver.   Hitchcock and Murphy  (1967b)£/
measured nitroreductase  activity using  parathion and paraoxon as sub-
strates.  When NADPH and FAD  were  used  as  cofactors, the mitochondria,
microsomes  and soluble fraction of rat  liver  contained 34, 38,  and  28%
of  the nitroreductase  activity.

     In 1967 Neal (1967a)-  used 32p-labeled parathion  to  identify metab-
olites in the tissues of male and female rats, male mice and  male guinea
pigs.  The metabolites found were paraoxon, diethyl hydrogen  phosphate,
diethyl hydrogen phosphorothionate and _p-nitrophenol.   Oxygen and NADPH
were required for maximal activity.  Phenobarbital or 3,4-benzopyrene
pretreatment increased the activity by  65 to 130%.   The reaction was in-
hibited by nitrogen and pure oxygen atmospheres as well as carbon monoxide.
Continuing these studies, Neal  (1967b)-' concluded that (in vitro)
inhibition of parathion metabolism indicated that the mixed function oxidase
system was a degradative pathway.  Inhibition with p-chloromercuribenzoate,
cupric ion and 8-hydroxyquinoline was more effective against  the con-
version of parathion to paraoxon than against its conversion to diethyl
hydrogen phosphorothionate.  Conversion of parathion to diethyl hydrogen
phosphorothionate was  stimulated by EDTA, barium and calcium ions.   The
electron acceptors, flavin adenine dinucleotide (FAD),  riboflavine,
menadione and methylene blue exhibited  a concentration-dependent inhibi-
tion of the conversion of parathion to  paraoxon or diethyl hydrogen phos-
phorothionate.  However,  the inhibition constants were different.

     A summary of these  reactions  is indicated by the following scheme:
I/  Matsumura, F.,  and  C.  T.  Ward,  "Degradation of Insecticides  by the
      Human and  the Rat Liver,"  Arch.  Environ.  Health.  13:257-261 (1966).
2/  Hitchcock, M.,  and  S.  D.  Murphy, "Enzymatic Reduction of 0,0-(4-
      Nitrophenyl)  Phosphorothioate, 0,0-Diethyl 0-(4-Nitrophenyl) Phos-
      phate, and 0-Ethyl 0-(4-Nitrophenyl).Benzene Thiophosphonate by
      Tissues from  Mammals, Birds,  and Fishes," Biochem.  Pharmaco1.t
      16(9):1801-1811 (1967b).
3/  Neal, R. A., "Studies  of  the Enzymic  Mechanism of the Metabolism  of
      Diethyl 4-Nitrophenyl Phosphorothionate  (Parathion) by Rat Liver
      Microsomes,"  Biochem. J..  105:289-297.(1967a).
4/  Neal, R. A., "Studies  on  the Metabolism of  Diethyl  4-Nitrbphenyl
      Phosphorothionate (Parathion) in vitro,"  Biochem. J.,  103:183-
      191 (1967b).
                                   80

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      Parathion	> Three minor metabolites
      Paraoxon    ^Diethyl hydrogen phosphorothlonate + £-nitrophenol
        l
      Diethyl hydrogen phosphate + £-nitrophenol
      NADPH	> Flavoprotein	>-Nonheme iron protein	^Cytochrome P-450
                    I                                          1
                Menadione                                      02
Differences in inhibition constants and inhibitions suggest that dif-
ferent enzymes or different enzymes systems may be involved in the
complete metabolism of parathion.

     Studies by Nakatsugawa and Dahm (1967)  showed that microsomes split
the aryl phosphate bond, and that NADPH2  and 02  are  required for the
reaction.  Further studies by Nakatsugawa et al.  (1969) confirmed that
aryl phosphate cleavage was mostly by liver  microsomal oxidases, in vivo,
using 32p_ and 35g-labeled parathion.  A minor portion was also catalyzed
by nonoxidative soluble enzymes requiring reduced glutathione.  They
suggested the following metabolic pathway.
                            Parathion - ^Diethyl  phosphorothioic acid
                               1
                            Paraoxon
      Desethyl paraoxon                   Diethyl phosphoric acid
                       \            *
                         Ethyl phosphoric acid
                                  I
                            Phosphoric  acid

     In a review of parathion metabolism, Dahm (1970)—  suggested that
paraoxon was not degraded by the same pathway as parathion.  Paraoxon
was metabolized by microsomes which required NADPH2, nicotinamide,
magnesium ion and potassium chloride for maximal activities.
\]  Dahm, P. A., "Some Aspects of the Metabolism of Parathion and Diazinon,"
      in Biochemical Toxicology of Insecticides. P. D. O'Brien and
      I. Yamamoto (Eds.), New York, Academic Press (1970).
                                  81

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      Jacobs en et al. (1973) found that the parathion W$Q in rats did
 not change after partial hepatectomy and suggested that parathion tox-
 icity is not due to the hepatic conversion of parathion to paraoxon.  An
 alternate explanation for the results is that the  remaining liver was
 sufficient to effect the conversion of parathion to paraoxon.

      Bass et al. (1972)—  reported that pretreatment of mice with DDT or
 DDE protected against parathion toxicity but not that of paraoxon.  In
 vitro.  the microsomes from mice given DDT or DDE converted more =S  to =0
 than those from the controls.  Detoxification of paraoxon was not altered
 by DDT or DDE.   The increased rate of conversion of parathion to diethyl-
 phosphorothioic acid could explain the decreased parathion toxicity after
 DDT or DDE.

      Alary and  Brodeur (1970) found a close relationship between the W$Q
 of parathion and paraoxon in male and female rats  and the in vitro  liver
 oxidative and hydrolytic metabolism.   Gagne and  Brodeur (1972)1/ used
 equitoxic doses of  32P-parathion in weanling and adult rats, and found
 that parathion  was  more toxic to weanlings  mainly  because of a lower
 liver enzyme activity.   Brain tissue  of weanlings  seemed more susceptible
 than that of adults but not because of an increased facilitation of para-
 thion or paraoxon across the blood-brain barrier.

                                3/
      Lichtenstein et al. (1973)-  reported  that  soluble liver fractions
 (from 105,000 and 500,000 x g) degraded parathion (207.)  and paraoxon  (657.)
 to water-soluble metabolites which were nontoxic to insects.

      Sakai and  Matsumura (1971)—' identified 14  esterase bands from human
 brain by thin-layer gel electrophoresis.  Four of  these were B-type
I/  Bass, S. W., A. J. Triolo, and J. M. Coon, "Effect of DDT on the
      Toxicity and Metabolism of Parathion in Mice," Toxicol. Appl.
      Pharmacol.. 22:684-693  (1972).
2/  Gagne, J., and J. Brodeur, "Metabolic Studies on the Mechanisms of
       Increased Susceptibility of Weanling Rats to Parathion," Can. J.
       Physiol. Pharmacol., 50:902-915  (1972).
31  Lichtenstein, E. P., T. W. Fuhremann, A. A. Hochberg, R. N. Zahlten,
      and F. W. Stratman, "Metabolism of [14C] Parathion and [^C] Para-
      oxon with Fractions and Subfractions of Rat Liver Cells," J. Agr.
      Food Chem., 21(3):416-423 (1973).
4/  Sakai, K., and jr. Matsumura, "Degradation of Certain Organophos-
      phate and Carbamate Insecticides by Human Brain Esterases,"
      Toxicol. Appl. Pharmacol.. 19(4):660-666 (1971).
                                   82

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esterases which degrade aIkoxyphosphate sites, and six were A-type
esterases which hydrolyze carboxyester sites.

     Norman et al. (1973a)—  reported that phenobarbital pretreatment in
rats decreased the apparent activation energy of the mixed-function oxi-
dase reactions.  These results were not entirely due to an increase in
cytochrome P-450.

                2/
     Neal (1972)-  measured the 1^ for paraoxon and  diethyl phosphoro-
thioic acid in rabbit lung and liver and found lung  to be much lower  in
activity.  The V^ax. ^or *-un8 microsomes was 20% of microsomes from  liver.
The mixed function oxidase from liver was induced by both phenobarbital
and 3-methylcholanthrene, whereas only phenobarbital induced the  lung mixed-
function oxidase.  In these studies, lung was about  3% as active  as liver.

                          3/
     Norman et al. (1973b)—  found that 3-methylcholanthrene and pheno-
barbital increased the metabolism rate of parathion by rough-surfaced,
but not by smooth-surfaced microsomes, based on microsomal protein con-
tent.  Phenobarbital and 3-methylcholanthrene increased the cytochrome
P-450 content; there was no difference in the metabolic rate between
the rough and smooth microsomes of untreated, and 3-methylcholanthrene-
or phenobarbital-treated animals.  However, based on the cytochrome P-450
in the entire microsome fraction, the metabolic rate was less  in the 3-
methylcholanthrene- and phenobarbital-treated rats than the controls.
Cytochrome P-450 is the terminal enzyme of the mixed-function oxidase sys-
tem.  The iron in the heme moiety exists in both the hi- and low-spin
state.  There was no correlation between the spin state and the rate of
parathion metabolism.

                             47
     Villeneuve et al. (1970)-  reported that SKF-525A had no effect on
parathion toxicity in rats while DDT, benzpyrene and phenobarbital
\l  Norman, B. J., J. A. Roth, and R. A. Neal, "Effect of Temperature on
      the Mixed Function Oxidase-Catalyzed Metabolism of 0,0-Diethyl j>-
      Nitrophenyl Phosphorothionate (Parathion)," Toxicol. Appl. Pharmacol.,
      26:203-208 (1973a).
2/  Neal, R. A., "A Comparison of the in vitro Metabolism of Parathion in
      the Lung and Liver of the Rabbit," Toxicol. Appl. Pharmacol., 23:
      123-130 (1972).
3_/  Norman, B. J., W. K. Vaughn, and R. A. Neal, "Studies of the Mechanisms
      of Metabolism of Diethyl £-Nitrophenyl Phosphorothionate  (Parathion)
      by Rabbit Liver Microsomes," Biochem. Pharmacol.. 22:1091-1101
      (1973b).
4/  Villeneuve, D. C., W. E. J. Phillips, and J. Syrotiuk, "Modification
      of Microsomal Enzyme Activity and Parathion Toxicity in Rats,"
      Bull. Environ. Contain. Toxicol., 5(2): 125-132 (1970).
                                   83

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decreased the toxicity by a factor of 3.  Fhenobarbital and DDT de-
creased hexabarbital sleeping time, but benzpyrene and SKF-525A increased
the sleeping time.

     Hollingworth et al. (1973)-' reported that glutathione-S-aryl trans-
ferase, a soluble enzyme, converted parathion to S-£-nitrophenylgluta-
thione and diethylphosphorothioic acid.  This enzyme can be differentiated
from the glutathione-S-alkyl transferase that is also present in rat tis-
sues .

                        2/
     Baeza et al. (1972)-  injected rats with 10 mg/kg of parathion to
produce a 50% inhibition of red cell acetylcholinesterase.  This could
be prevented by  exposing the animals to 1,000 ppm of CO for 90 min prior
to treatment.  When  1.06 mg/kg of  paraoxon was injected intraperitoneally
no symptoms or mortalities were observed in rats.  When the dose was in-
creased to 1.42  mg/kg,  symptoms were observed but there were no deaths.
However, if 1,000 ppm of CO were given  prior to 1.06 mg/kg of paraoxon,
80% of the animals exhibited symptoms and 40% died.  If 2,500 ppm CO were
given prior to administration of 1.42 mg/kg paraoxon, 70% of the animals
died.

     Parathion pretreatment decreased the normal metabolism of testo-
sterone by rat liver microsomes (Stevens, 19731/).  All polar and non-
polar metabolites were  decreased except for a 307. increase in one dione.

     Weiss et al.  (1964)£/ reported that parathion did not alter the blood
sugar levels in  rabbits, dogs, or  rats.

     Taylor and  Gaut (1968) reported that phenothiazines potentiated  the
toxicity of parathion.
 _!/  Hollingworth, R. M., R. L. Alstott, and R. D. Litzenberg,  "Gluta-
       thion S-Aryl Transferase in the Metabolism of Parathion  and Its
       Analogs," Life Sci.. 13:191-199 (1973).
 2/  Baeza, C., A. M. Goldberg, and R. J. Rubin, "Effect of Carbon
       Monoxide on Response to Parathion and Paraoxon," Toxicol.  Appl.
       Pharmacol., £2(2):288 (1972).
 3/  Stevens, J. T.,  "The Effect of Parathion on the Metabolism of %-
       Testosterone by Hepatic Microsomal Enzymes from the Male Mouse,"
       Pharmacology.  10(4):220-225 (1973).
 4/  Weiss, L.  R., J. Bryant,  and 0. G. Fitzhugh, "Blood Sugar  Levels
       Following Acute Poisoning with Parathion and 1-Naphthyl  N-Methyl
       Carbamate (Sevin)  in Three Species,"  Toxicol. Appl. Pharmacol.,
       6(3):363 (1964).
                                    84

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Tissue Residues - Jensen et al.  (1952)  found that intravenous 35S-para-
thion did not accumulate in the blood,  organs or tissues of rabbits.
Fankaskie et al. (1952) found no accumulation of parathion or free p-
aminophenol in the blood, milk or urine of cows fed 1 to 32 mg/kg/per day
parathion.  Roan et al. (1969) measured parathion levels in the serum of
aerial applicator pilots.  Some pilots  had high serum parathion levels
and low cholinesterase activity but were asymptomatic.  Giachetti et al.
(1966) gave rats 1 mg/kg of parathion IP and measured brain levels of
paraoxon.  At 6 hr after injection, the brain contained 30 to 33 ng of
paraoxon.  Only traces remained after 72 hr.

Summary - The following major points can be stated regarding the metabo-
lism of parathion:

      1.  Parathion is readily absorbed through the skin, from the stomach
          and the lung.

      2.  Parathion is widely distributed throughout the body but does not ac-
          cumulate at any site and causes no effect other than the irrevers-
          ible binding of paraoxon to cholinesterase.

      3.  The major metabolites of parathion that are excreted are aminopara-
          thion, jj-nitrophenol, diethylphosphorothioic acid, ethylphos-
          phoric acid and sulfate.

      4.  Metabolism of parathion is in two general steps:  activation
          and detoxification.

      5.  Parathion is enzymatically hydrolyzed to paraoxon by the mixed-
          function oxidase system.

      6.  Oxidation of parathion and/or paraoxon is inhibited by carbon
          monbxide and SKF-525A.

      7.  Phenobarbital, 3-methylcholanthrene and benzpyrene stimulate
          parathion metabolism.

      8.  Microsomal oxidation of parathion requires NADPHj, oxygen,
          potassium chloride and magnesium ion for maximum activity.

Effects on Reproduction

     The effects of parathion on reproduction are reviewed in the fol-
lowing two subsections on domestic animals and wild avian species.
                                     85

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 Domestic Animals - Some years ago, a study was made on the effect of
 parathion on reproduction and milk production in goats by Wilber and
 Morrison (1955). .As a test material, they utilized parathion liquid
 with a purity of 98.76% or as a 257. wettable powder.  They administered
 oral daily doses of 16 mg/kg (25% wettable powder) for 16 days.   The total
 dosage given to one goat was 8,960 mg.  After death the goat was found
 to be carrying two fetuses which would have been born in approximately
 10 days.  The authors pointed out that parathion did not induce  an abor-
 tion in the goat.  When another goat was killed near the terminal point
 of chronic poisoning, she was found to be carrying two 3-month-old fetuses.
 Superficially, the fetuses appeared normal in all respects.  They found
 that the RBC cholinesterase activity (ApH) of heart blood of the fetuses
 was 0.14 and 0.17 respectively.  The control value for the mother was
 about 1.05.  However, her value dropped to 0% of normal before necropsy.
 In order to ascertain whether some anticholinesterase material crossed
 the placenta and exerted an effect on the fetus, fetuses were taken from
 unpoisoned goats carrying fetuses of different ages.  The RBC cholinesterase
 value of the nonpoisoned fetuses ran from 1.33 to 1.74.  Compared with the
 above data, the blood of fetuses from lactating goats poisoned with para-
 thion was depressed by about 85%.  They investigated the milk production
 of three goats that received total doses ranging from 900 to 1,060 mg
 intramuscularly.  The dosage for the goats on the milk test was  10 daily
 injections at a dose of 0.5 mg/kg followed by five daily injections at
 1 mg/kg.  These were then followed by five more daily injections at a
 dose of 2 mg/kg.  They found no significant increase or decrease in milk
 production as compared with control periods that could be ascribed to the
 parathion treatment.  The production of milk by all goats decreased
 sharply after initiating the final dosage, which was aimed at killing the
 animals in a short time.

      In reference to reproductive studies, Beck (1953)—  investigated the
 effect of certain insecticides  on the motility and metabolism of mam-
 malian spermatozoa using boar semen.   From oxygen-consumption experi-
 ments,  the  data indicated that  DDT,  aldrin, and malathion had a  minor
 inhibitory  effect on respiration of boar spermatozoa,  whereas parathion,
 BHC,  and TEPP had an intermediate effect.   The insecticides had  a pro-
 nounced effect on the  motility   of the spermatozoa.   The motility was
 practically gone 120min after parathion treatment.  Furthermore,  para-
 thion had only a weak  inhibitory effect on glycosis  of spermatozoa.

Wild  Avian  Species  - There  is a large  volume of literature on the effect
 of chlorinated  hydrocarbons upon avian species.   This  interest has been
I/  Beck, S. D., "Effect of Insecticides on  the Metabolism and Motility
      of Mammalian Spermatozoa," J. Econ. Entomol.. 46:570-574 (1953).
                                    86

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largely due to the propensity for  chlorinated hydrocarbons  to accumulate
in fatty tissue.   The organic phosphorus  insecticides degrade rapidly
and have fewer latent effects than the more  residual chlorinated hydro-
carbons.  Barnett (1950)-' fed parathion  to  pheasants at  levels of  100
and 1,000 ppm, and he noticed a decreased gonadal  activity, and there
was also a loss in total body weight.  Shellenberger et al.  (1966)-'
noted a similar weight loss in Japanese quail that were fed 5 ppm of
Azodrin R.  Muller and Lockman (1972)2/ fed  subtoxic doses  of dieldrin and
parathion to yearling mallards to  observe the effect on egg production,
fertility, hatchability, shell thickness, and progeny growth.  Their test
groups were fed 10 ppm of parathion in the diet.   The treatment was started
30 days prior to egg production and continued for  90 days thereafter.
Parathion failed to exert significant effects upon egg production,  fertil-
ity, or progeny growth.  Hatchability was depressed for those animals
receiving dieldrin, but parathion  had no  effect.   The only measurable
effect of parathion was a significant reduction in mean shell thickness.
The thinner shells do not restrict successful embryonic development.
Neill et al.  (1971)*' conducted a  similar study using the gray partridge
as a test bird.  These birds received 8 ppm  of  parathion.  Here, again,
parathion did not have an effect upon egg production, fertility, and
hatchability.  Eggs from the dieldrin treatment had a high percentage  of
dead-in-the-shell embryos which could be  attributed to  the residue of
dieldrin that was found in the eggs.  No  parathion residues were detected
in the eggs.  The only effect noted from parathion in these studies was
a high percentage of early and late dead  embryos;  the investigators
hypothesized  that undentified parathion degradation products may have  been
present in the eggs, resulting in an adverse effect on  the metabolism,  and
thereby accounting for a high percentage of  dead-in-the-shell  embryos.
 It  Barnett,  D.  C.,  "The Effect of Some Insecticide Sprays on Wildlife,"
       Proc.  30th Ann.  Conf.  West.  Assoc. State Game and Fish Commissioners.
       pp.  125-134 (1950).
 27  Shellenberger, T.  E.,  6. W. Newell, R. F. Adams, and J. Barbaccia,
       "Cholinesterase  Inhibition and Toxicologic Evaluation of Two
       Organophosphate  Pesticides in Japanese Quail," Toxicol. Appl.
       Pharmacol.. 8:22-28  (1966).
 3/  Muller,  H. D., and D.  C. Lockman, "Fecundity and Progeny Growth
       Following  Subacute Insecticide Ingestion by the Mallard," Poul.
       Sci..  51:239-241 (1972).
 4/  Neill, D. D., H. D. Muller, and J. V. Shutze, "Pesticide Effects on
       the Fecundity  of the Gray Partridge," Bull. Environ. Con tarn.
       Toxicol.,  6(6)-.546-551 (1971).
                                    87

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Furthermore,  there was no  alteration by either  of  the insecticides in
the  growth  rate.

Teratogenic Effects

Mammals  -   It has been reported by Kimbrough and Gaines  (1968)—   that
parathion can produce teratogenic effects  in Sherman rats.  The dosages
were 3.0 and  3.5 mg/kg given intraperitoneally  on  the llth day of pregnancy.
The  fetuses were removed on the 20th day of pregnancy.  The results are
shown in Table  14.

      The average weight gain of the dams was drastically reduced; the
number of fetuses was reduced by half.   The number of resorptions was
high and the  weight  of the fetuses from parathion-treated mothers was
30%  less than the controls.
      Fish  (1966)2./  investigated  the  teratogenic potential of  parathion
and  methyl  parathion in rats. Dosage  levels were  chosen which represented
about one-sixth, one-fourth, one-half,  and three-fourths of  the estab-
lished oral or  intraperitoneal LDsQ.   The  doses were  given intraperitoneally
in a vehicle  of ethanol  (20%) and propylene glycol (80%).  The injections
were made  on  day 8,  9,  15, or 16  of  gestation.   In the  search for anomalies,
particular  attention was directed to the external  appearance  of the  embryo.
Particular  attention was given to the  appearance of the brain, cervical
and  thoracic  cord, heart and liver.  Fish  found no significant differences
between  control and  treated animals  for fetal mortality, fetal weight, or
gross anomalies.  Brain cholinesterase was reduced in the embryo  brain.
He did observe  some  large  subcutaneous  hematomas in the offspring of para-
thion-treated groups.  The weight of the offspring from the  parathion-
treated  animals was  uniformly less  than that of the offspring of  the con-
trols over  the  first 40 days of  life.   There was also a significant  in-
crease in stillbirths  and neonatal  deaths for  the animals that were ex-
posed to parathion.  There has been  a  comment made in the Mrak Report
(1969)2/ that Fish's (1966) data were  like those observed with organo-
chlorines.  That is, the action  of  these two classes  of insecticides
suggest  that  they do not produce specific  teratogenic  effects.
j./  Kimbrough, R. D., and T. B. Gaines, "Effect of Organic Phosphorus
      Compounds and Alkylating Agents  on  the Rat Fetus," Arch. Environ.
      Health, 16:805-808 (1968).
27  Fish, S. A., "Organophosphorus Cholinesterase Inhibitors and Fetal
      Development," Am. J. Obstet. Gynecol.. 96(8):1148-1154 (1966).
V  Mrak, E. M., "Report on the Secretary's Commission on Pesticides
      and Their Relationship to Environmental Health," U.S. Dept. HEW,
      p. 665 (1969).
                                    88

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00
                                        Table  14.  THE TOXIC AND TERATOGENIC EFFECT OF PARATHION GIVEN
                                           INTRAFERITONEALLY TO RATS ON THE 11TH DAY OF PREGNANCY*





Compound
Control
Farathion
Control
Parathion



Dose
(mg/kg)
„
3.5

3.0
Lowest dose
to kill
nonp regnant
rat
(urn/kg)
..
4

--

/
NoX
pregnant
rats
4
5
5
5
Average
weight
gain
of dams
(g)
67.78
42.27
75.24,.
41.79*'

Average
no.
fetuses
per litter
10.8
5.6
12.6
7.6

Average
no . dead
fetuses
per litter
0
0.2
0
0
Average
no.
resorptions
per no.
pregnant rats
0.5
7.0
0.8
3.8
c/
Average— Average
weight
of
fetuses
(R)
3'57b/
2.46-
3.34
2.86b-/
weight
of
placentas
(g)
0.69
0.53
0.54
0.44-'

No. and

type
of malformations
per total
None
no. fetuses

1/28 fetus edetnatous
None
None


      *  Data from Kimbrough and Gaines, op. cit. (1968).
      a/  In some pregnant rats all fetuses were resorbed, thus reducing the total numbers
            of litters.
      b/  Significantly different from controls, p < 0.05.
      c/  Weight of dead fetuses was included.

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      Existing data on the transfer of parathion through  the  placenta
 to the fetus  are limited.  Fischer and Plunger  (1965)!/  did  not  find any
 traces of parathion in a human fetus  from a mother who had taken a fatal
 dose  of parathion.  A study using pregnant guinea pigs also  failed to
 demonstrate that parathion crosses  the placenta.  It has been  shown by
 Fish  (1966) that either methyl parathion or parathion given  to pregnant
 rats  inhibits brain cholinesterase activity in  the embryos.  Methyl para-
 oxon  has been detected in the  brain,  liver, and muscle of the  embryo
 (Ackermann and Engst,  1970?./).   Villeneuve et al. (1972)!/ used  1*C-
 parathion in  a study of placental transfer in sheep.  ^C-parathion was
 administered  to the dam over a 5- to 15-sec time interval using a jugular
 cannula.  The dosage level was  0.1 rag/kg of body weight.  Blood  samples
 were  drawn from the fetus, and the mother and amniotic fluid was col-
 lected at 5-min intervals initially and at longer periods of time there-
 after for 48  hr.   Plasma cholinesterase activity in the  dam  was  maximally
 depressed within 30 min (52%).   At 48 hr the plasma cholinesterase was
 still depressed by 307«.   In the fetus, maximum depression occurred at 40
 min and then  plateaued at 20%,  4 hr after administration.  After 48 hr
 the activity  was  depressed in  the fetus 9.2%.   Only a small  portion (2 to
 57o) of the radioactivity in the fetal plasma was in the  form of  parathion.
 The remainder of the  radioactivity was in the  form of unidentified metab-
 olites.   All  the radioactivity from the parathion in the amniotic fluid
 was in the form of an unidentified  metabolite.  The results  reported in
 this  paper agree with other information on the  metabolism of parathion
 in ruminant animals where the  pathways are quite different from  those of
 rodents  or humans.  It has been shown by O'Brien (1960)^' that,  in the
 cow,  parathion is degraded to j>-aminophenol and then conjugated  to form
 a  glucuronide.   In humans and  rodents, the major pathway involves the
 formation of  paraoxon followed  by hydrolysis to £-nitrophenol, or the
 direct hydrolysis of parathion to j>-nitrophenol which is then  glucu-
 ronidated and excreted in the urine.
_!/  Fischer, R., and C. Plunger, "Detection and Quantitative Determinq-
      tion of Phosphorus Insecticides in Biological Material," Mitt Arch.
      Toxicol.. 21:101-105  (1965).
2/  Ackermann, H., and R. Engst, "Presence of Organophosphate Insecticides
      in the Fetus," Arch.  Toxikol.. 26:17-22 (1970).
3/  Villeneuve, D. C., R. F. Willes, J. B. Lacroix, and W. E. J. Phillips,
      "Placental Transfer of l^C-Parathion Administered Intravenously to
      Sheep," Toxicol. Appl. Pharmacol.. 21:542-548 (1972).
kj  O'Brien, R. D., Toxic Phosphorus Esters, New York:  Academic Press,
      pp. 227-228 (1960).
                                    90

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Avian Embryo toxic Ity  - There have been a number of reports of the toxic-
ity of parathion on avian embryos (Khera and Bedok, 1967;—' Khera and
Lyon, 1968;2/ Khera and Clegg, 1969;!/ Roger et al., 1969;*/ Oga et al.
197ll/ and Yamada, 19716/) .  Khera and Bedok (1967) reported the follow-
ing toxicity when 1 mg of parathion was injected into the egg sacs of
4-day incubated chicken eggs:  the shape and course of the notochord was
distorted.  This distortion was associated with disproportionate and
irregularly spaced anlagen of various axial structures.  Khera and Lyon
(1968) determined that chicken eggs injected on incubation days 0,4, and 7,
and duck eggs injected on days 0, 4, 7, and 10 were insuitable for toxic-
ity studies.  There was a large variation among replications, lack of
dose-response relationships, and in some cases low sensitivity to the
specific lethal effect.  There was a more marked mortality response at
mid-incubation for both species (10 days in chick and 13 days in duck
embryos).  There were indications that duck embryos provide less vari-
able results than chick embryos.  Roger et al. (1969) studied the tera-
togenic effect of bidrin  in hen eggs.  He included a number of other
organophosphorus compounds in his study and reported on parathion.  He
observed that the injection of 1 mg of parathion/egg produced a definite
If  Khera, K. S., and S. Bedok, "Effects of Thiol Phosphates on Notochordal
      and Vertebral Morphogenesis in Chick and Duck Embryos," Food Cosmet.
      Toxicol.. 5:359-365 (1967).
2/  Khera, K. S., and D. A. Lyon, "Chick and Duck Embryos in the Evalua-
      tion of Pesticide Toxicity," Toxicol. Appl. Pharmacol.. 13:1-15
      (1968).
51  Khera, K. S., and D. J. Clegg, "Perinatal Toxicity of Pesticides,"
      Can. Med. Assoc. J.. 100:167-172 (1969).
4/  Roger, J-C., D. G. Upshall, and J. E. Casida, "Structure-Activity
      and Metabolism Studies on Organophosphate Teratogens and Their
      Alleviating Agents in Developing Hen Eggs with Special Emphasis
      on  Bidrin," Biochem. Pharmacol.. 18(2):373-392 (February 1969).
£/  Oga, S., C. C. Pellegatti, S. Reis, and A. C. Zanini, "Toxic and/
      or Teratogenic Activity of Anticholinesterase Compounds.  I.
      Tetatogenicity of Parathion in Chicken Embryos," Rev. Farm. Bio-
      quim. Univ. Sao Paulo, 9(2):343-355 (1971).
6/  Yamada, A., "Teratogenic Effects of Organophosphorus Insecticides in
      the Chick Embryo," Osaka Shiritsu Daigaku Igaku Zasshi, 21:245-255
      (1972).
                                   91

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 shortening of the spine of the embryo.   Thirty percent had  abnormal
 feathers and 10% parrot-beak.   When Oga et al. (1971)  evaluated  the
 teratogenic effects of parathion administered to eggs  at  levels  59.23,
 118.46,  or 296.15 Jig/egg,  he demonstrated dose dependency in  the in-
 tensity  of malformations.   The highest  dose-inoculated group  showed a
 maximum  incidence of teratogenic effects (44%) with treatment on the
 8th day  of embryogenesis.   The embryos  treated at the  highest dose of
 parathion on the 8th day showed total body malformation,  overall edema,
 ankylosis of the lower limbs,  asymmetric implantation  of  the  limbs, and
 intestinal atony.  Embryos inoculated  at 59.23 ug of  parathion  exhibited
 only limb malformations.

      An  effect on embryo development in hens' eggs was also reported by
 Marliac  (1964).I/  A concentration of 0.1 mg of parathion per egg produced
 malformed embryos.

     Lutz-Ostertag et al.  (1969a,  b),^2/ Meiniel  et al. (1970) £/ and
 Lutz-Ostertag et al.  (1970)!/  studied the  teratogenic  effects of para-
 thion in quail.   Lutz-Ostertag et al. (1970)  also investigated the
 development of pheasant, duck,  and chick embryos  as affected by para-
 thion.   The teratogenic effects of parathion on the skeleton  of Japanese
 quail were studied by Meiniel  et al.  (1970).   They immersed Japanese
 quail eggs  in a  mixture of acetone and  parathion  which contained 20 mg
 of  parathion per liter of  acetone.  The immersion time was 30 sec.  They
 observed inhibition of growth  of the  appendicular skeleton, which is con-
 sidered  a serious  malformation as well  as  considerable retardation of
 the growth of the  axial skeleton.   The  most  common deformities were
 lordosis  of the  neck and numerous flexions  in the sagittal plain.  Neural
\l  Marliac, J.  P., "Toxicity and Teratogenic Effects of 12 Pesticides in
      the Chick Embryo." 48thAnn. Meeting Fed. Amer. Soc. Exp. Biol..
      105 (1964).
2/  Lutz-Ostertag, Y., R. Meiniel, and H. Lutz, "Action du parathion sur
      le developpement  de  1'embryon de caille," C. R. Acad. Sci.,
      Paris, Series D, 268:2911-2913 (1969a).
3^1  Lutz-Ostertag, Y., R. Meiniel, and H. Lutz, "Effects du parathion
      sur le developpement de 1'embryon de caille et de certains de ses
      organes in vivo et in vitro," Biol. Abstr.. 52(22):12, 271 (1969b).
4/  Meiniel, R., Y. Lutz-Ostertag, and H. Lutz, "Teratogenic Effects of
      Parathion (Organophosphorus Insecticide) on the Skeleton of the
      Embryo of the Japanese Quail (Coturnix coturnix japonica)," Arch.
      Anat. Microsc. Morphol. Exp., 59(2):167-183 (1970).
5J  Lutz-Ostertag, Y., R. Meiniel, and H. Lutz, "Parathion, Embryonic
      Development, Sterilization and Estrogenic Effects in Birds; Com-
      parison with the Effects of Aldrin," Annee Biol., 9:501-507 (1970).
                                    92

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centers and arches were evident tn many of the cervical vertebrae.   Also
the vertebral musculature was disorganized.  Nonincubated eggs of pheasant,
quail, duck, and chickens were immersed in an acetone-parathion solu-
tion containing 20 g of parathion per liter (Lutz-Ostertag et al.,  1970).
Other eggs received injections of 1 g of commercial parathion (10% Al/liter)
carried in 0.08 to 0.50 ml of Tyrodes solution.  All of the embryos from
eggs that were immersed and survived past 9 days of incubation were
severely deformed.  Deformation was exhibited by nanism, lordosis of the
neck, celosomia, light edema, achondroplasia, anury, club-shaped feather-
buds and abnormally positioned hind-legs with crisped digits were noticed.
The livers were abnormal.  The most interesting features were the changes
in the urogenital tract.  The gonads were partially or  completely sterilized.
Parathion had acted as an antimitotic substance, markedly affecting cell
division.  The Mueller's canals of the male embryos were partially re-
tained.  The right Mueller's canal in female embryos was  completely re-
tained.  Quail embryonic testes were isolated from the  embryo and cul-
tivated (5 days) in vitro in the presence of pesticides (Lutz and Lutz-
Ostertag, 1972).—' The testes appeared healthy; however, upon histologi-
cal examination there were changes in structure.  The testicular tubules
were vacuolized:  the gonocytes and Sertoli cells disappeared completely.
Quail embryo ovaries cultivated under the same conditions manifested
similar changes.  The effect on the chick embryo was not as broad.  Only
the selective disappearance of all the gonocytes was manifest.  It fur-
ther has been reported that the ovary of the chick embryo undergoes more
or less .complete suppression of the corta (Lutz-Ostertag and Meiniel,
1968).-'

     Dunachie and Fletcher (1969)—' used the eggs of white leghorn
chickens for teratogenic studies.  They used the yolk injection method.
Parathion was far less toxic when dissolved in acetone, compared to corn
oil.  Eighty-nine percent of the eggs hatched at the concentration of
50 ppm and only 19% at 500 ppm.  Considering the high toxicity to mammals
of parathion, the embryonic mortality was surprisingly  low.   The amount
of deformities is variable but severe only at 500 ppm.   Various combina-
tions of parathion and ma la thion have been evaluated.  Both mortality
I/  Lutz, H., and Y. Lutz-Ostertag, "The Action of Different Pesticides
      on the Development of Bird Embryos," Dru%s and Fetal Development,
      Froc. International Symposium on the Effect of Prolonged Drug
      Usage on Fetal Development, Beit-Berl, Kfar Saba, Israel, September
      1971, pp. 127-150 (1972).
2/  Lutz-Ostertag, Y., and R. Meiniel, "In vitro Sterilizing Effect of
      Parathion on Embryonic Ovaries of Chick  and Quail," C. R. Acad.
      Sci., Paris,  Series D, 267:2178-2180 (1968).
3/  Dunachie, J. F., and W. W. Fletcher, "An Investigation of the Toxicity
      of Insecticides to Birds' Eggs Using the Egg-Injection Technique,"
      Ann. Appl. Blol.. 64(3):409-423 (1969).

                                   93

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and deformities were high  (38%) for parathion in a 5:50-ppm mixture with
malathion.  The hatchability of 100% parathion and no malathion was 65%,
whereas a dose of  100% malathion reduced hatchability to 87%.  A 50:50
mixture of  these two organophosphate insecticides produced a hatchability
of 71%.

     Some very interesting observations have been made by Khera and Clegg
(1969) relative to  the prenatal toxicity of pesticides.  These authors
point out that the  use of  avian eggs as a test organism has a serious
fault in that it is difficult to extrapolate to mammalian species.  The
greatest difference between the avian embryos and mammalian species is
that the avian embryo is nonplacental.  Since it is isolated from the
maternal organism,  the avian embryo cannot benefit from the natural de-
fense mechanisms which safeguard the mammalian embryo.  Furthermore, the
phylogenetic relationship  between avian species and man is remote.  Mam-
malian data indicate that  in most cases, extremely large dose levels
(when compared to  the human exposure levels) are required to induce
neonatal effects or embryotoxicity.  These investigators concluded it
was unlikely that any pesticide presently in use is liable to cause
damage to the perinatal human, at normal exposure levels.  They felt that
this position was supported by the lack of epidemiological data connect-
ing pesticides to perinatal toxicity in humans.

     Paraoxon was one of the compounds included in a study of Flockhart
and Casida  (1972)i/ in which they attempted to correlate the degree of
inhibition of esterase in  the yolk sac membrane to teratogenic effects
of organophosphate  insecticides.

    The teratogenic effects were shown to be unrelated to hydrolysis of
diphenylacetate by homogenates of yolk sac membranes.  For example, both
paraoxon and EPN gave similar degrees of esterase inhibition, but only
paraoxon treatment  of hens' eggs resulted in teratogenic effects.

Crustaceans - Pesticides may get into estuarine water by drainage from
nearby treated fields, or when the pesticide is used as a control in
salt marshes and estuaries for mosquitoes.  Studies have been made by
Butler et al. (1962)£/ on  the effect of pesticides on adult oysters.
I/  Flockhart, I. R., and J. E. Casida, "Relationship of the Acylation
      of Membrane Esterases and Proteins to the Teratogenic Action of
      Organophosphorus Insecticides and Eserine in Developing Hen Eggs,"
      Biochem. Pharmacol.. 21:2591-2603 (1972).
2/  Butler, P. A., A. J. Wilson, Jr., and A. J. Rick, "Effect of Pesti-
      cides on Oysters," Proc. Nat. Shellfish Assoc.. 51:23-32 (1962).
                                    94

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Thirty-one compounds were investigated by Davis  (I960)- as to their ef-
fect on fertilized eggs and larvae of bivalves.  It was the opinion of
these investigators that the effect of pesticides on growth is the most
sensitive index for these molluscs for establishing a level that would
(highest concentration) have no appreciable effect on the survival of
embryos, or on the survival of the fully formed  veliger larvae.  Davis
and Hidu (1969)—' were interested in the effects of various compounds
(52 compounds, including 17 insecticides) on the development of fertilized
eggs of the hard clam, Mercenaria mercenaria, and the American oyster,
Grassestrea virginica, and on the survival and growth of the larvae.
Parathion concentrations in the water, were 0.25, 0.50 and 1.0 ppm.  They
did not measure the number of oyster eggs developing or the survival of
the larvae, but they did determine that the percent of increase in the
length of the larvae was depreciated from 1037. to 227o at the higher con-
centration.  No evaluation was made for parathion for the reduction of
the number of eggs ultimately developing into normal larvae from oyster
and clam eggs.

Behavioral Effects

     Al-Hachim and Fink (1968a, b, and c)^?-' have studied the behavioral
effects of DDT and parathion upon young mice whose mothers were previ-
ously treated with these compounds.  They measured minimal electroshock
seizure threshold (1968a) at 70 to 90 days of age, the condition of
avoidance response  (1968b) at 30 through 37 days of age, and open-field
behavior (1968c) at 60 to 66 days.  In all of these studies the mothers
were given a dosage of 3 mg/kg of parathion during the first,  second,
J./  Davis, H. €., "Effects of Some Pesticides on Eggs and Larvae of
      Oysters (Grassestrea virginica) and Clams (Venus mercenaria),"
      Commer. Fish. Rev.. 23(12):8-23 (1960).
2/  Davis, H. C., and H. Hidu, "Effects of Pesticides on Embryonic De-
      velopment of Clams and Oysters and on Survival and Growth of the
      Larvae." Fish. Bull.. 67(2):393-403 (1969).
3/  Al-Hachim, G. M., and G. B. Fink, "Effect of DDT or Parathion  on  the
      Minimal Electroshock Seizure Threshold of Offspring from DDT- or
      Parathion-Treated Mothers," Psychopharmacol.. Berlin,  13:408-412
      (1968a).
4/  Al-Hachim, G. M., and G. B. Fink, "Effect of DDT or Parathion  on  Con-
      dition Avoidance Response of Offspring from DDT- or Parathion-Treated
      Mothers," Psychopharmacol., Berlin, 12:424-427 (1968b).
£/  Al-Hachim, G. M., and G. B. Fink, "Effect of DDT or Parathion  on  Open
      Field  Behavior of Offspring from DDT- or Parathion-Treated Mothers,"
      Psychol. Rept.. 22:1193-1196  (1968c).
                                    95

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 and  third  trimester.   There was  no  effect upon brain excitability, con-
 ditioned avoidance  response,  or  open-field behavior of mice whose mothers
 had  received  the  parathion.   Out of the  three tests, the only response
 that was obtained was  from DDT which produced a delayed acquisition of
 controlled avoidance response.   The brain excitability and the open-field
 behavior of the young  were normal.

     It was postulated that since parathion  is metabolized and excreted
 by the mammals within  a few days after ingestion,  its effects on the
 central nervous system seem to be transient, having an effect for a few
 weeks after birth and  disappearing  when  the  offspring becomes older (2
 months).

                           1 2/
     Spynu (1952  and 1957)-=^=-' studied the conditioned reflexes of cats
 that had been dosed with 5, 3, and  2 mg/kg of parathion in three separate
 experiments (quoted by Medved et al., 19643-').  At a dosage of 5 mg/kg
 orally, the conditioned reflexes of the  cat were slowed within 10 to  15
 min.  The  animal  returned to  normal in 3 days.  After the 3 mg/kg dosage,
 it required 3 hr  to establish a  lowering of  the conditioned relfexes.
 No changes could  be found in  animals given 2 mg/kg.

 Toxicity Studies  with  Tissue  Cultures

                                                                 4/
     Tissue cultures were first  used by  Lewis and  Richards (1945)—  to
 determine  the toxicity of DDT on chicken embryo tissues.  Gabliks and
 Friedman (1965)—' used HeLa cells and Chang  liver  cells in an attempt to
JV  Spynu, E.  I.,  "Data  Concerning the  Toxicology  of  the  Insecticide Niuiph
       100 and  the  Establishment  of Tolerance Limits," Dissertation, Kiev
       (1952).
2J  Spynu, E.  I.,  "The Effect  of Some Organophosphorus  Insecticides on  the
       Higher Nervous Activities  and on  the  Cholinesterase Activity," The
       Chemistry and Application  of Organophosphorus Compounds, Acad. Sci.
       USSR (Ed.),  Moscow (1957).
3/  Medved, L. I., E. I. Spynu,  and lu.  S.  Kagan,  "The  Method of  Con-
       ditioned Reflexes  in  Toxicology and Its Application for Determin-
       ing the Toxicity of Small  Quantities  of Pesticides," Residue Rev..
       6:42-74  (1964).
4/  Lewis, W. H.,  and A. G.  Richards, Jr.,  "Non-Toxicity  of DDT on Cells
"      in Cultures," Science, 102:330-331 (1945).
5/  Gabliks, J., and L.  Friedman,  "Responses of Cell  Cultures to  In-
~~      secticides.  I.  Acute Toxicity to Human Cells,"  Proc. Soc. Exp.
       Biol. Med..  120:163-168  (1965).
                                     96

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study insecticidal toxicity.   The first evaluation of organophosphate
insecticides in tissue cultures was  conducted by Gabliks  et al.  (1967).—
They found very little correlation between mouse liver cell cultures and
human strain Chang liver cells.  Litterst et al. (1969 and 1971)-!-' used
tissue cultures to investigate the toxicity of a number of insecticides
including parathion, paraoxon, and £-nitrophenol.  In the earlier study
(1969) they also used HeLa cells.  They evaluated growth inhibition and
synthesis of proteins and nucleic acids in their cultures.  They ob-
served that organophosphate compounds were more toxic than the chlorinated
compounds.  It was found that paraoxon, an oxidation product of para-
thion, was less toxic at 40 ppm than parathion.  In contrast, £-nitro-
phenol at the same concentration (40 ppm) appeared to be slightly more
toxic.  If they increased the treatment levels to 250 and 500 ppm, both
paraoxon (at 250 ppm) and £-nitrophenol (at 500 ppm) caused nearly com-
plete inhibition of cell growth.  The synthesis of DNA at a concentration
of 10 ppm of the insecticide indicated that only diazinon produced any
changes.  Aspirin and sodium chloride were included as positive controls
in the test.  The same effect observed with Diazinon®was produced by
these two chemicals.  It should be pointed out that a test level of 10
ppm is relatively high as related to concentrations of insecticides
normally found in human tissues (with the exception of DDT).  When the
parathion concentration was raised to 50 ppm, there was a 50% inhibition
in cell growth in 48 hr.  Litterst and Lichtenstein (1971) extended the
above studies to include the cells of nonmalignant origin.  They chose
normal diploid skin fibroblasts.  They evaluated parathion, carbaryl,
and several metabolites  such as £,£*-DDE, paraoxon, £-nitrophenol, and
1-naphthol.  The response to the normal cells was the same as previously
reported with a malignant cell line, in that parathion was more toxic
than paraoxon, and £-nitrophenol was as toxic as parathion.  It should
be emphasized that these results are exactly the opposite of data ob-
tained when animals are used as test organisms.  In general, little dif-
ference was found between the responses of  the malignant  (HeLa) and the
nonmalignant (fibroblast) cells to the environmental  toxicants.  In
JL/  Gabliks, J., M. Bantug-Jurilla, and L. Friedman, "Responses  of Cell
      Cultures to Insecticides.  IV.  Relative Toxicity of Several
      Organophosphates in Mouse Cell Cultures," Proc. Soc. Exp.  Biol.
      Med..  125:1002-1005 (1967).
2/  Litterst, C. L., E. P. Lichtenstein, and K. Kajiwara, "Effects of
      Insecticides on Growth of HeLa Cells," J. Agr. Food Chem., 17:
      1199-1203  (1969).
:*/  Litterst, C. L., and E. P. Lichtenstein, "Effects and Interactions
      of Environmental Chemicals on Human Cells in Tissue Culture,"
      Arch.  Environ. Health. 22:454-459  (1971).
                                    97

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 review, it is difficult to make relevant predictions concerning the
 effect of -a pesticide utilizing human cells in tissue culture.  Under
 the conditions of the tests reported, the interaction at the level of
 synthesis of macromolecules is dependent upon the cell line and the addi-
 tive used, and in general, there is no significant interaction between
 the two.

 Mutagenic Effects

      Dikshith (1973).^ studied the in vivo effects of parathion on guinea
 pig chromosomes.  He injected male guinea pigs with a single intratesti-
 cular injection of 0.05 mg of parathion in 0.5 ml of ethanol.  The animals
 were killed after 24 hr.  He determined the percentage of chromosomal
 changes at metaphase, and these results are shown in Table 15.   Chromosome
 abnormalities were induced by parathion treatment in the meiotic chro-
 mosomes of the male guinea pig.  In some cases, the individual morphology
 of the chromosomes was totally lost (chromosomal pulverization).  Al-
 though it was not common,  parathion did induce the formation of exchange
 figures.  In essence, Dikshith 's (1973) work confirmed the fact that
 cell division was inhibited at metaphase.  It had been previously con-
 jectured by Lutz-Ostertag et al. (1969a and 1969b) that parathion in-
 duces  embryonic abnormalities because of defective cell division.

 Oncogenic Effects

     No ocogenic studies per se were found concerning parathion  as an
initiator of tumor development in animals.   However,  one study described
the effect of parathion upon the possible reduction of tumors  produced  in
animals by treatment with a potent carcinogen.   No tumors  were reported in
the two year feeding studies.
      Buchet and Lauwerys (1970 and 1971)i   had observed that certain
 organophosphate esters inhibit tissue lipo lysis in vitro and in vivo.
 Others have observed that mammary tumor incidence in rats appears to be
 influenced by the quality and the quantity of the dietary fat.  Rats
 maintained on a diet containing 20% corn oil developed more mammary
 tumors after treatment with a single dose of 7, 12 -dime thy lbenz( a) anthracene
 \l  Dikshith,  T.  S.  S.,  "In vivo Effects of Parathion on Guinea Pig
       Chromosomes,"  Environ. Physiol.  Biochem.,  3:161-168 (1973).
 2J  Buchet,  J.  P., and R.  Lauwerys,  "Inhibition  of Rat Heart Diolein Hy-
       drolase  and Brain  Acetylcholinesterase by  Organophosphate Esters
       in  vitro."  Bibchim.  Biophys. Acta. 218:369-371 (1970).
 3_/  Buchet,  J.  P., and R.  Lauwerys,  "Characterization of a Diglyceride
 "     Lipase in Rat  Heart  and Intestine," Life Sci.. 10:371-376 (1971).
                                    98

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Table 15.  PERCENTAGE OF CHROMOSOMAL CHANGES AT METAPHASE OF MALE GUINEA
             PIGS AFTER PARATHION (0.05 MG/TESTICAL) TREATMENT*
  Number of cells scored     Number of cells observed and percent frequency
              507.                            Clumping and
             ethanol  Para-  Fragmentation   liquification
Control^
200
200
200
200
control
200
200k/
200
200k/
thion
200
200
200
200
Cells
31
28
23
37
Percent
15.50
14.00
11.50
18.50
Cells
14
19
15
18
Percent
7.00
9.50
7.50
9.00
Other types
--
—
—
Observed
Chromatid
bridge in
one cell
      200     200      200    24     12.00    10      5.00

Average 200   200      200       14.30            7.60
Source:  Dikshith,  op.  cit.  (1973);  reprinted from Environmental Physiology
            and Biochemistry by permission of the publisher.   Year of
            first publication,  1973.
&/  Chromosomal changes were not noticed in any of the cells scored.
b/  One to two cells showed features of clumping otherwise all cells
      scored were normal.
                                    99

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 than  rats  fed a  low  fat diet.  Lauwerys and Buchet  (1972)—  evaluated the
 effect of  parathion  on mammary carcinoma produced by 7,12-dimethylbenz-
 (a)anthracene (DMBA).  They  injected parathion  twice a week into rats for
 12 weeks at a level  of 0.5 mg/kg  followed by  1 mg/kg intraperitoneally
 three times a week for 11 weeks.  The  triamiphos was included in the diet
 of another group of  rats, at a concentration  of 20  ppm.  Two weeks after
 the beginning of the different treatments, all  rats were given 0.5 ml of
 DMBA  solution (5 mg) orally  and the treatment was repeated for 5 weeks.
 Animals were autopsied at the time of  death or  at the end of the test
 period of  23 weeks.  The carcinogenic  action  of DMBA observed during
 this  study is summarized below.

                             Total         Number of
                             tumor         tumors per       Latent period
   Treatment group         incidence    tumor-bearing rat      in days

  Parathion                    100               2                66
  Control                       90               2.6              66
  Triamiphos                    60               1.6              73
  Control                      100               2.3              66

 There was  no reduction of tumor incidence in  the parathion treated group.
 The lower  tumor  incidence in the  triamiphos may be  due to its reduction
 of tissue  lipolytic  activity.  The administration of parathion may have
 allowed a  return of  normal lipolytic activity between successive injec-
 tions .

 Effects on Humans

 Acute and  Subacute Toxicity  - There are extensive literature references
 to acute and subacute poisoning of humans by  parathion, largely presented
 as individual or group clinical cases.  In most of  these instances the
 actual amounts of parathion  ingested,  absorbed  or inhaled were not known.
 Hayes (1967)—' has summarized the susceptibility of man and other animals
 to a  number of pesticides, including parathion  (Tables 16 and 17).  Para-
 thion is a highly toxic chemical  with  a fatal dose  for man at a level
 of 2  mg/kg for a single dose.  The oral lethal  dose of parathion is
_!/  Lauwerys, R., and J. P. Buchet, "Effect of Two Organophosphorus
      Esters on Mammary Carcinogenesis by 7,12-Dimethylbenz(a)anthracene,"
      Eur. J. Toxicol.. 5:163-167  (1972).
2/  Hayes, W. J., Jr., "Toxicity of Pesticides to Man—Risks from Present
      Levels." Proc. R. Soc. Lond., 167(1007):101-127 (1967).
                                    100

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                        Table  16.   SPSCEPTIBILXTY OF MAN.AND OTHER ANIMALS
                                 TO SINGLE ORAL DOSES OF PARATHION

f*
W W
0 U
4J 4) 4>
M (^ *|.j
O «W J3 M-l
j3 W *j w
4J l-l
1-4 r-l $ rH
3 CO CO
U AJ O
4J -H CO -rl
(0 0 V C
41 *r( r-4 *f-f
00 r-l r-t rH
n o g o
co B
Species ^ OT
Man
Child
Calf
Sheep 50
Steer 25
Dosage(mg/kg)

r-l O
CO 4)
O JZ  O eg co ri S5
0) B rt
S co i-J
6.4
—
0-5
75



r-l
CO

CO
|V|

>>t
4J i-j
CO r-l B
4) CO rl
i-4 4J O
rH CO O M-l
f&K ITl -rl
P .S
cn 3 &
2-0 — 13
0-1 — --
1-5 — —
20 — —












References
a/,*/
S.I
d/
Q /
d/
a/  Goldblatt, M. W., "Organic Phosphorus Insecticides and the Antidotal Action
      of Atropine," Fharm. J.t 164:229-233 (1950).
b/  Hayes, W. J., Jr., 1963 Clinical Handbook on Economic Poisons, PHS
~~     Publication No. 476, Washington, D.C. (1963).
£/  Kanagartatnam, K., W. H. Boon, and T. K. Koh, "Parathion Poisoning
      from Contaminated Barley," Lancet. 1:538-542 (1960).
d/  Radeleff et al., op. cit. (1955).

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               Table 17.  THE SUSCEPTIBILITY OF MAN AND OTHER ANIMALS
                         TO REPEATED ORAL DOSES OF PARATHION
Species
Man
Dosage
(mg/kg/day)
0-1
Duration
(days)
42
Results
33% reduction of whole blood ChE;
References
Rat (F)


Dog

Pig
0-26


0-047

4-0
 84


168

 49
  167. Inhibition of RBC ChE; 377.
  inhibition of plasma ChE

807. reduction of RBC ChE; slight
  inhibition of plasma ChE

607. inhibition of plasma ChE

80% inhibition of RBC ChE; no
  inhibition of plasma ChE
£/  Edson et al., op. cit. (1964)
b/  Frawley and Fuyat, op. cit. (1957).

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estimated to be 1.43 rag/kg of body weight for a man (DuBois, 1958).-
Aa much as 0.1 mg/kg/day continuously administered for 42  days signifi-
cantly reduced plasma and RBC cholinesterase.   Lethality has been re-
ported by Hayes (1963) following the ingestion by adult humans of 900,
120, and 50 mg of parathion.
                                                           2-6/
      Rider and his associates (1963, 1964, 1967, 1969a, b)	  conducted
a number of experiments on human volunteers from the San Quentin Prison
in California to establish tolerances for various insecticides in man.
Over a 10-year period, they worked with parathion, methyl  parathion,
malathion, EPN, Systox®,dichlorvos, OMPA, CARDONA, and Guthion®.  Most all
of their experiments were conducted over the same time, frame, which was
oral ingestion of a capsule of various dosages of the insecticides for a
30-day period.  There was one exception (1963) in which the experiments
ran for 50 days.  Before the evaluations began, the prisoners were given
physical examinations, and a base was established for their plasma and
RBC cholinesterase.  During the 30-day test, blood samples were taken
twice a week for esterase activity.  Rider and Moeller (1963) and Rider
et al. (1969b) ran experiments using parathion on prisoners.  Rider and
Moeller (1963) and Rider et al. (1969a) reported on the effect of four
dosage levels of parathion:  3.0, 4.5, 6.0 and 7.5 mg/day.  They observed
only a slight depression of plasma cholinesterase for levels of 3.0, 4.5
and 6.0 mg.  However, at the level of 7.5 mg/day, on day 4 the plasma
cholinesterase of one subject was down to 73% of his pretest level.  On
day 9 two of the subjects had values of 64% and 687. of their control
levels, and on day 16 these two subjects had cholinesterase depressions
of 507. and 527. of their pretest level.  At this point in the experiment
I/  DuBois, K. P., Postgrad. Med. J., 24:278-288 (1958).
2j  Rider, J. A., and H. C. Moeller, "Tolerance of Organic Phosphates in
      Man," Progress Report of Franklin Hospital Foundation, San Francisco,
      California (1 October 1963).
.37  Rider, J. A., and H. C. Moeller, "Studies on the Anticholinesterase
      Effects of Systox and Methyl Parathion in Humans," Fed. Proc.,
      23(2):176 (1964).
4/  Rider, J. A., H. C. Moeller, and E. J. Puletti, "Continuing Studies
      on Anticholinesterase Effect of Methyl Parathion, Initial Studies
      with Guthion, and Dichlorvos on Humans," Fed. Proc., 26(2):427  (1967).
5J  Rider, J. A., H. C. Moeller, E. J. Puletti, and J. I. Swader, "Toxic-
      ity of Parathion, Systox, Octamethyl Pyrophosphoramide, and Methyl
      Parathion in Man," Toxicol. Appl. Pharmacol.. 14(3):603-611  (1969a).
(J  Rider, J. A., and E. J. Puletti, "Studies on the Anticholinesterase
      Effects of Gardona, Methyl Parathion, and Guthion in Human Subjects,"
      Fed. Proc.. 28(2):479 (1969b).
                                     103

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 the  average  plasma  cholinesterase for  the five subjects was decreased by
 28%  from the control  value.   Some depression of red blood cell cholin-
 esterase was also noted at the dosage  of 7.5 mg of parathion per day.
 The  lowest red  cell cholinesterase values obtained were 63, 78, and 86%
 of the  pretest  levels.  These data are in agreement with those of Edson
 et al.  (1964).

 Symptoms of  Parathion Poisoning  - The  symptoms of mild exposure to para-
 thion as a result of  orchard  spraying  or other activities associated in
 the  fruit-growing industry have  been described by Sumerford et al.
 (1953>=  and Arterberry et al. (1961) ."LI  The modes of exposure and the
 symptomatology  have been discussed by  Hamblin and Golz (1955).  The signs
 and  symptoms of 246 patients  admitted  to a hospital in Greece with acute
 parathion poisoning have been reviewed by Tsachalinas et al. (1971) ..3/
 Namba (1971)!/  has  presented  an  excellent description of the signs and
 symptoms of  organophosphate   poisoning in patients.  Reference should be
 made to Hamblin and Golz's paper (1955) for the onset and progressions
 of symptoms  in  subjects exposed  to  toxic amounts of parathion in spray-
 ing  operations. Namba  (1971) has classified the signs and symptoms ob-
 served  in 77 patients who developed poisoning by the application of ethyl
 and  methyl parathion. The more  prominent symptoms were weakness, nausea
 or vomiting,  excessive sweating, headache and excessive salivation.  Namba
 points  out that if  the exposure  to organic phosphorus insecticides is suf-
 ficient to produce  symptoms,  they usually appear in less than 12 hr.
 Symptomatology  that appears 24 hr after exposure is unlikely to be due to
 these pesticides.   A  critical clinical observation is the occurrence of
 tniosis,  which is found in about  50% of the patients, and the latter
 symptom appears in  subjects even in the mild cases.  Death is usually
 attributed to failure of the  respiratory muscles and paralysis of the
 respiratory  center.   Cardiac  involvement may occur, but is usually seen
\J  Sumerford, W. T., W. J. Hayes, Jr., J. M. Johnston,  K. Walker, and
      J. Spillane, "Cholinesterase Response and Symptomatology from Ex-
      posure to Organic Phosphorus Insecticides," AMA Arch. Ind. Hyg.
      Occup. Med., 7:383-398  (1953).
2J  Arterberry, J. D., W. F. Durham, J. W. Elliot, and H. R. Wolfe,
      "Exposure to Parathion," Arch. Environ. Health. 3:476-485  (1961).
2/  Tsachalinas, D., G. Logaras, and A. Paradelis, "Observations on 246
      Cases of Acute Poisoning with Parathion in Greece," Eur. J. Toxicol.,
      4:46-49 (1971).
t*J  Namba, T., "Cholinesterase Inhibition by Organophosphorus Compounds
      and Its Clinical Effects," Bulletin of the World Health Organiza-
      tion, 44:289-307 (1971).
                                  104

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only at the terminal stage.  Man appears to be more sensitive to the
organophosphate insecticides in that he exhibits symptoms earlier than
experimental animals, particularly central nervous system manifestations.
If an untreated organophosphate-poisoned victim is alive after 24 hr»
he is likely to recover.  The account by Kanagaratnam et al. (1960)-' de-
scribes a parathion poisoning incident resulting from the use of con-
taminated barley in India.  There were 53 persons involved, and the
clinical features described included collapse, fits, sweating, dyspnoea,
the effect on the pupils, the eye, blood pressure, coma, and muscular
fasciculation.

     Gershon and Shaw (1961)-' felt that chronic exposure to organophos-
phate compounds produced psychiatric disorders in orchard workers.  In
a small field survey, they observed in 14 men and two women schizophrenic
and depressive reactions with severe impairment of memory and difficulty
in concentration.  The range of exposure for these subjects was 1-1/2 to
10 years.

     No other surveys of this nature were found in the literature.

     Brown (1971)-' reported on the electroencephalographic changes and
disturbance of brain function following organophosphate exposure.
Acute organophosphate poisoning disturbs central nervous system func-
tions by causing disorientation in space and time, a sense of depersonaliza-
tion, and hallucinations; with heavy exposure, convulsions occur.  Acute
inhibition of brain cholinesterase would be expected to cause effects
related to the temporal lobe.  EEC changes in acute organophosphate
poisoning have been reported to resemble those seen in the interictal EE6
of temporal lobe epileptics.

Dermal Effects - The information in this subsection is concerned with
observations that were made during controlled exposure to parathion.
Other data on the relationship of exposure to occupational hazards of
dermal contact are discussed in a later subsection.

                        4/
     Fredriksson (1961a)-  and Fredriksson et al. (1961) conducted a study
on the distribution of labeled parathion within the skin, and on the
_!/  Kanagartanam, K., W. H. Boon and T. K. Hoh, "Parathion Poisoning  from
      Contaminated Barley, "Lancet 1;538-542  (1960).
 2/  Gershon, S., and F. H. Shaw, "Psychiatric Sequelae of Chronic  Exposure
      to Organophosphorus Insecticides," Lancet. pp. 1371-1374  (1961).
 3/  Brown, H. W., "Electroencephalographic Changes and Disturbance of
      Brain Function Following Human Organophosphate Exposure," Northwest
      Med.. 70:845-846  (1971).
 ty  Fredriksson, T., "Studies on the Percutaneous Absorption of Parathion
      and Paraoxon.  Part II.  Distribution of 32P-Labeled Parathion
      Within the Skin," Acta Derm. Venerol..  41:344-353  (1961a).
                                   105

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hydrolysis and metabolism of this insecticide within the skin.  Previous '
to their work, there had been no other studies using autoradiographic
techniques to evaluate the cutaneous distribution of parathion which had
been applied topically.  Evaluations were made from skin samples taken
from man, cat, rabbit and rat (Fredriksson, 1961a).  Human skin was ob-
tained at autopsy within 10 hr after death, and pieces of this skin were
nailed to a board.  Six microliters of ^2P-labeled parathion was then
evenly distributed on an area of the skin of about 1.5 cm2.  The para-
thion was allowed to remain in contact with the skin for 1/2, 1, 2, 4 or
24 hr.  After the exposure period, the parathion was usually blotted off
the skin, and samples were frozen and examined by autoradiographic tech-
niques.  It was found that parathion appeared to penetrate to some ex-
tent into hair follicles and sebaceous glands, although no certain con-
clusions could be drawn regarding the routes of absorption.  There was
some increased activity below the epidermal layers.  In another study
(Fredriksson et al., 1961), the possible occurrence of skin enzymes
capable of metabolizing parathion and paraoxon was investigated.  Tissue
slices of liver and skin were cut and the hydrolysis of parathion was
measured by the Warburg method.  It was found that parathion was not hy-
dro lyzed or transformed into paraoxon by the skin of man, cats, rats or
rabbits.  Paraoxon was hydro lyzed by the skin of all species except rats,
and the enzymatic action occurred at the fastest rate in the rabbit.  The
hydrolysis in rabbit skin amounted to about 207. of the paraoxon in 1 hr.
In the skin from man and cat the rate of hydrolysis was about 17..

     Hayes et al. (1964)-' and Funckes et al. (1963)2-/ investigated the
excretion of £-nitrophenol and the depression of RBC cholinesterase in
human volunteers that were subjected to exposure of parathion under
s trenuous circumstances.

     Hayes et al. (1964) reported on three series of tests to evaluate
the potential hazard of dermal exposure to parathion under controlled
conditions.

     Series 1 involved exposure of the hand and right forearm of volun-
teers to 2% parathion dust, 2% emulsion or 47.5% emulsifiable concentrates,
After the toxicant was distributed over the hand and forearm, they were
I/  Hayes, G. R., Jr., A. J. Funckes, and W. V. Hartwell, "Dermal Ex-
      posure of Human Volunteers to Parathion," Arch. Environ. Health,
      8:829-833  (1964).
2/  Funckes, A. J., G. R. Hayes, Jr., and W. V. Hartwell, "Urinary Ex-
      cretion of Paranitrophenol by Volunteers Following Dermal Exposure
      to Parathion at Different Ambient Temperatures," J. Agr. Food Chem.,
      11:455-457 (1963).
                                  106

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 then secured  in a polyethylene bag and placed in a constant temperature
 chamber.  The treatments were as follows:

       1.  Exposure to 5 g of 2% parathion dust for 2 hr on
          five successive days at 105*F.

       2.  Exposure to 4 liters of 2% parathion emulsion for
          70  min at 81°F.

       3.  Exposure to 47.5% parathion emulsifiable concen-
          trate for 120 min at 69°F.

       4.  Same as No. 3 except for 90 min at 100°F.

No significant changes in cholinesterase activity and no clinical signs
were noted.

     In Series 2,  a volunteer exposed his entire body to 2% parathion
dust.  The dust was rubbed on the bare shoulders, back and chest, and
then he put on a rubberized suit.  Seven pounds of the dust was poured
over the shoulders and down into the suit.  The suit was closed and
sealed.  There were two exposures for 7.5 and 7 hr with an interval of
6 weeks between exposures.  The temperature was 60°F.  In a later test
a male volunteer sat in a chamber, exposed totally except for his head,
and was exposed to a vapor generated by heating 2% parathion powder to
200°F.  The duration of exposure was 3 hr.

     In the first test plasma cholinesterase activity was depressed to
44% of  baseline at 24 hr after the initiation of the test, but was within
12% of normal within 120 hr.  The volunteer in the second test did not
experience symptoms of poisoning.  The plasma cholinesterase was depressed
to 82% of normal.

     In Series 3,  filter paper pads (900 cm2) were allowed to absorb their
capacity of equal values of parathion and ether.  The pads were placed
on the backs of volunteers and covered with plastic sheeting.  Two
volunteers were exposed twice for 3 hr to pads containing 40 to 50 g of para-
thion at temperatures of 54°, 79°, and 104°F.

     Significant depression in cholinesterase activity of red blood cells
did not occur.  The cholinesterase activity was depressed 20% in plasma
Immediately after exposure at 104°F.  There were no signs of poisoning.
                                   107

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     The  investigators commented  that some individuals can sustain high
dermal exposure  to parathlon without signs of poisoning or suffering
severe depression of cholinesterase activity.

     In another  study  (Funckes et al., 1963), data on the excretion of
£-nitrophenol and blood cholinesterase activity were measured in volun-
teers exposed to parathion dust.  The exposure consisted of weekly 2-
hr applications  of 27. parathion dust to two volunteers maintained at
environmental temperatures ranging from 58° to 105°F.  In these studies
only the  hand and forearm were exposed in a bag containing the test in-
secticide.  These investigators found that there was a significant change
in £-nitrophenol excretion in urine following dermal exposures at tem-
peratures above  82°F.

     More recently Maibach et al. (1971)—  investigated the penetration
of parathion, malathion, and carbaryl through the skin of volunteers by
using labeled pesticides.  The only variable in the experimental design
was the anatomical site of application of the dose, which was regulated
at 4 ug/cmr of skin.  Applications of pesticide were made to the follow-
ing anatomical regions:  forearm, palm, foot (ball), abdomen, hand
(dorsum), fossa  cubitalis, scalp, jaw angle, postauricular, forehead,
ear canal, axilla, and scrotum.   They found that approximately 8.6% of
parathion when applied to the forearm was absorbed, and all other absorp-
tion was  referenced to the forearm data.  Slightly more parathion pene-
trated the palm  and the ball of the foot, whereas the abdomen and the
dorsum of the hand permitted twice as much penetration as the forearm.
The fossa cubitalis had twice the penetration of the forearm.  The hairy
areas such as the scalp, the angle of the jaw, the postauricular area
and forehead had four  times more  penetration than the forearm, whereas
the axilla had five times as much, and penetration from the scrotum was
essentially complete.

                        2/
     Durham et aL (1972)—  measured excretion of j>-nitrophenol as an
indicator for the degree of exposure of orchard spraymen to parathion.
Both respiratory and dermal absorption were studied.  From the evidence
in their study they concluded that skin contamination is potentially .
more important as a route of absorption than the respiratory route al-
though not necessarily more important in terms of poisoning.  The data
\J  Maibach, H. I., R. J. Feldmann, T. H. Milby, and W. F. Serat, "Regional
      Variation in Percutaneous Penetration in Man," Arch. Environ. Health,
      23:208-211 (1971).
2/  Durham, W. F., H. R. Wolfe, and J. W. Elliott, "Absorption and Excre-
      tion of Parathion by Spraymen," Arch. Environ. Health, 24:381-
      387 (1972).
                                   108

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showed that much larger amounts ,f parathion Impinge on the skin than are
breathed in the lungs.  These authors emphasize the importance (need) to
protect the skin from exposure.

     It is understood that environmental factors will have an influence
on the potential occupational hazards associated with use of insecticides.
With the exception of studies with workers in pesticide plants, the bulk
of information on exposure toxicity comes from studies carried out in
outdoor work situations.

     One study, however, was done in which greenhouse workers were ob-
served during a 3-month exposure to parathion in a greenhouse.  Addi-
tionally, determination of cholinesterase levels of these employees were
made 5 weeks after the last application of insecticide (Culver et al.,
1958i/).  In their summary of findings these authors stated that on
plant surfaces (in the greenhouse) parathion was present at initial con-
centration from 80 to 200 ppm and had an average half-concentration time
of 80 hr.  It was further shown that the red blood cell cholinesterase
depression in the workers could not be definitely correlated to measured
exposures to parathion although such a correlation was inferred.  The
red blood cell cholines terase depression ranged from 15 to 20% and the
size of this depression was not sufficient to elicit signs of intoxica-
tion.
                     7 /
     Malkinson (I960)—  states that "Although the largest number of cases
of toxic absorption (industrial poisoning) follows respiratory inhalation
many industrial poisons are absorbed through the skin.  .  ."

     Although poisoning with parathion often results from entry of the
material by two or more routes (absorption through skin, respiratory
tract, conjunctive or gastrointestinal tract) many instances have been
reported where toxicity resulted primarily by absorption  through the
skin (Batchelor and Walker, 1954;!/ Hamblin and Marchand, 195lft/).
JL/  Culver, D., J. Kinosian, W. Thielen, and R. Graul, "A Study of Ex-
      posure to Parathion in a Greenhouse," AMA Arch. Ind. Health, 18:
      235-247 (1958).
2/  Malkinson, F., "Percutaneous Absorption of Toxic Substances in In-
      dustry," AMA Arch. Ind. Health, 21:87-99 (1960).
_3/  Batchelor, G. S., and K. W. Walker, ''Health Hazards  Involving In-
      Use of Parathion in Fruit Orchards of North Central Washington,"
      Arch. Ind. Hyg.. 10:522 (1954).
4/  Hamblin, D. 0., and J. F. Marchand, "Parathion  Poisoning," Am.
      Practitioner and Dig. Treatment, 2:1 (1951).
                                   109

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Inhalation Effects  - Reports  that assess the hazards from occupational
exposure  to parathion suggest  that  the majority of the occupational acci-
dents are due  to dermal exposure.   The following information on inhala-
tion is concerned with observations under controlled conditions.  Other
information on respiratory exposure is discussed under Occupational Ex-
posure Hazards.  Hartwell et  al.  (1964)-' made a controlled study of
respiratory exposure to volunteers  from parathion.  The volunteers were
fitted with a  breathing tube  and  a  face mask which was attached to a
toxic-vapor-generating chamber, in  which parathion was placed  in open
trays as  a liquid or powder and heated to various temperatures.  The up-
take of parathion through the breathing apparatus was not measured.  In
one series of  tests on each of four consecutive days, exposure was main-
tained for 30  min to a vapor  from 1 ml of fresh technical parathion
spread over 36 in2  and heated to  105° to 115°F.  On the 5th day the
amount of parathion was raised to 5 ml, spread over an 80 in^ surface,
and heated to  150°F.  Under these conditions, after five exposures, the
red blood cell cholinesterase was depressed by 9870 and the activity of
plasma cholinesterase was depressed by 837..  In another series, a volun-
teer breathed  through a mask  attached to the 6-ft x 6-ft x 8-ft plyboard
chamber for 2-1/2 hr.  In this chamber, panels of cheese-cloth 3 ft x
6 ft were saturated with technical  parathion and attached to the interior
walls.  In addition, technical parathion was sprayed into the chamber.
The temperature of  the chamber was  100°F.  The subject remained well
after breathing air from this  chamber.  Based on £-nitrophenol excretion
as an indicator, it was calculated  that the average exposure amounted
to 2.5 mg equivalents of parathion  absorbed.  After 2-1/2 hr the cho-
linesterase activity of the red blood cells was depressed about 24%.  The
investigators  felt  that their study confirmed the generally accepted
respiratory exposure hazard afforded by parathion.  Relating these levels
to Edson's (1957)2/ work, where the latter demonstrated that cholinesterase
activity  was depressed 33% after  ingested oral doses of 7.6 mg, Hartwell
et al. (1964)  felt  that the hazard  to respiratory exposure of humans to
parathion was  at least three  times  greater than ingestion.
J./  Hartwell, W. V., G. R. Hayes, Jr., and A. J. Funckes, "Respiratory
      Exposure of Volunteers  to Parathion," Arch. Environ. Health. 8:
      820-825 (1964).
2/  Edson, E. F., "Effects of Prolonged Administration of Small Daily
      Doses of Parathion in Rat, Pig and Man," Mineograph Bulletin,
      Essex England:  Chesterford Park Research Station NR Saffron
      Walden, p. 22 (March 1957).
                                     110

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Occupational and Accidental Exposure Hazards - The occupational hazards
will be broadly considered as those exposures sustained by workers in
field operations and workers in manufacturing operations.

     Field operations - The occupational hazards of spraying parathion
have been investigated by a number of workers.  A very early paper by
Williams and Griffiths (1951)!/ was concerned with the individual symptoms
and cholinesterase level in the blood of sprayers.  Others have reported
specifically on the effects to humans in spraying operations only
(Griffiths et al., 1951;2-/ Ganelin et al., 1964;!/ Bick, 1967*/).  More
complete studies involving all of the types of personnel that are con-
nected with spraying operations such as field men, warehousemen, and
residents in the area have been reported by Sumerford et al. (1953),
Hayes et al. (1957),I/ Arterberry et al. (1961).

     Milby and Ottoboni (1963)-  reported  on  an  epidemic of parathion
poisoning is a 50 mile square area around  Hughson, California.  In this area
there were 250 peach orchards with a total area  of 24,000 acres.  There
were 5,000 to 8,500 peach pickers in this  area between early August and
mid-September.  The peaches were picked  manually in hot weather.  Dur-
ing this season, 94 workers were poisoned  by  parathion.  Cholinesterase
determinations were obtained in 68 of the  94  cases and were found to be
depressed in 66 patients.  One death occurred which was attributed to
parathion poisoning.


     Two pounds of actual parathion were sprayed per acre (as a 25% wet-
table powder) on 20 March, 20 May, 25 June and 27 July.  Picking was
started on 8 August.
I/  Williams, J. W., and J. T. Griffiths, "Parathion Poisoning in Florida
      Citrus Spray Operations," J. Fla. Med. Assoc.. 37:707-709 (1951).
2/  Griffiths, J. T., C. R. Stearns, Jr., and W. L. Thompson, "Parathion
      Hazards Encountered Spraying Citrus in Florida," J. Econ. Entomol.,
      44:160-163 (1951).
,37  Ganelin, R. S., C. Cueto, and G. A. Mail, "Exposure to Parathion:
      Effect on General Population and Asthmatics," J. Amer. Med. Assoc.,
      188:807-810 (1964).
4/  Bick, M., "The Effect of Blood Cholinesterase Activity of Chronic
      Exposure to Pesticides," Med. J. Aust.. 2:1066-1070 (27 May 1967).
5_/  Hayes, W. J., Jr., E. M. Dixon, G. S. Batchelor, and W. M. Upholt,
      "Exposure to Organic Phosphorus Sprays and Occurrence of Selected
      Symptoms," Public Health Reports. U.S. Dept. HEW, Public Health
      Service, 72(9):787-794 (September 1957).
6i/  Milby, T. H., and F. Ottoboni, "Report of an Epidemic of Organic
      Phosphate Poisoning in Peach Pickers, Stanislaus County,
      California," State of California Department of Health, Bureau of
      Occup. Health (1963).

                                    Ill

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      Analysis  was  performed  for parathion residues  on  leaf and fruit sam-
 ples.  The  contamination of  workers'  exposed  skin was  also determined.
 The  air was sampled  in three orchards in the  breathing zone of the workers
 These sources  of information led to an estimate  of  the total dose by all
 routes of < 4,000  ug/day.  The  analyses performed by Milby and Ottoboni
 are  summarized below.
         Source

 Oral
  Four  peaches per  day  (residue
     level  of  0.5  ppm by weight)

 Dermal
  Palms of hands  (63 in2  total and
     7 ug/in2  maximum)
  Backs of hands, forearms  and face
     (351 in2  total  and  4.7  ug/in2 total)
  Neck  (40 in  and  1.4  ug/in2 maximum)
  Remainder of trunk

 Respiratory
  Airborne dust (35 ug/m^ and breathing
     rate of 10 m3/day)

           Total dose
   Parathion
    (KG)
    500/day
    440/day

  1,650/day
     56/day
    960/day
    350/day

< 4,000/day
Data from Milby and Ottoboni, pp. cit. (1963).


     Quinby and Lemmon  (1958)—   evaluated  the effects of residues left
in orchards on workers  involved  in picking,  thinning, cultivating, and
irrigating.  Williams and Griffiths  (1951),  in a study of orchard sprayers,
concluded that there should be a reassessment of the relationship of
blood cholinesterase to the development of symptoms.  It had been con-
sidered earlier than parathion poisoning would not be evident in such
workers unless the blood cholinesterase level dropped to about 25% of
normal.  However, these workers  observed symptoms of parathion poison-
ing when the plasma cholinesterase levels were as high as 90% of their
control values, and the red blood cell cholinesterase was reduced to no
\J  Quinby, G. E., and A. B. Lemmon, "Parathion Residues as a Cause of
      Poisoning in Crop Workers," J. Amer. Med. Assoc., 166(7):740-746
      (1958).
                                    112

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to no lower than 60 to 70% of the normal control values.  In the five
cases studied, four of the persons exhibited symptoms of poisoning when
the red blood cell cholinesterase was between 50 and 757. of normal.
Jegier (1964)i/examined 52 subjects for dermal and respiratory exposure
during a spraying season in the Provience of Quebec.  It was found that
the maximum exposure for parathion, malathion, Sevin®, endrin and
Guthion® was less than 1% of the toxic dose.  Spraying activities in-
cluded air blast spraying of apple orchards and field spraying of vegetables
and grain.  A study of parathion poisoning cases reported during citrus
spray operations in Florida orchards was reported in 1950 (Griffiths et
al., 1951).  Of the 48 cases reported, eight were shown to be definitely
not parathion poisoning, and 15 others were highly questionable.  The
remaining 25 cases were assumed to be poison cases.  However, a positive
diagnosis was lacking because of the absence of blood tests for cholin-
esterase.  These investigators suggested that skin absorption was the
primary cause of parathion poisoning in these cases, and that handgun-
spray operators appeared to have far more skin exposure than speed-
sprayer operators.  By checking the residues of parathion on the respirator
filter discs, they obtained additional evidence in that the hand spray
gun operators retained more parathion on their respiratory filter discs.
An extensive study of symptomatology and cholinesterase response after
exposure to organophosphorus insecticides has been reported by Sumerford
et al. (1953).  This study involved a total of 258 persons, 805 samples
of red blood cells, and 802 samples of plasma which were analyzed for
cholinesterase.  The workers were divided into eight groups:

     •  Mixing plant personnel (MPP)

     .  Commercial applicators (CA)

     •  Part-time applicators (PTA)

     •  Workers in orchards (WO)

     •  Field men, warehousemen and miscellaneous workers (FWM)

     •  Residents living near orchards (RNO)

     •  Residents far from orchards (KFO)

     •  Residents outside area (ROA)
I/  Jegier, Z., "Health Hazards in Insecticides Spraying of Crops," Arch,
      Environ. Health. 8:670-674 (1964).
                                     113

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This  study was  conducted  in the  apple  growing  area  in Wenatehee,
Washington, where  two  types of sprays  were used, parathion and  tetra-
ethylpyrophosphate,  and no  effort was  made to  separate the effects of
these two organic  phosphate insecticides.   This study was summarized
with  the following remarks:

      1.  The  cholinesterase values  for those groups known to have defi-
nite  and consistent  exposure (MPP,  CA  and PTA) were low, and the lowest
cholinesterase  values  were  exhibited by the mixing plant personnel (MPP).

      2.  As one would  expect, those workers who had little or no expo-
sure  to insecticides maintained  normal average cholinesterase values.

      3.  The  only  fatal or  near  fatal  cases resulted from brief massive
exposures and gross  carelessness rather than long-standing exposure.

      4.  When an illness  was characterized by  miosis or by any  three of
a group of selected  symptoms, it was possible  to make a diagnosis of
poisoning if, in addition,  the cholinesterase  values were significantly
reduced.

      They found no serious  poisoning in the absence of excessive expo-
sure  or severe  depletion  of cholinesterase values.  There were  occurrences
of mild illness in many of  these workers when  their cholinesterase values
fell  within normal ranges.   A follow-up study  was made in the same area
by Hayes et al. (1957) during the subsequent 2-year period, with the sub-
jects again grouped  in the  same  order  as described  in the work  reported
above.  Two hundred  twenty-eight persons were  involved in the follow-
up study, and these  included 100 of the same subjects studied previously.
About the same  number  of  persons were  evaluated in  1953.  In the latter
study only commercial  applicators,  residents near orchards, residents
far from orchards, and residents outside the area were compared.  The
results of the  follow-up  study confirmed the previous demonstrated re-
lationships between  blood cholinesterase levels, exposure and illness.
It was again  concluded that miosis  or  three or more selected symptoms
are good criteria  for  the diagnosis of mild poisoning.  No contradic-
tions in results were  found in the  1952 to 1953 test when compared to
the 1951 observations.  This paper  also reported for the first  time that
symptoms resembling  mild  poisoning  are not significantly more common in
persons from  an agricultural community  than in persons living in a non-
agricultural  area.  A  third  survey  (Arterberry et al., 1961) was made
                                   114

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in this same area In Wenatchee, Washington, and again involved several
occupational groups that were studied in 1951, and in the 1952 to 1953
reports.  About 115 persons were involved in the 1958 exposure study,
99 blood samples were analyzed for plasma and erythrocyte cholinesterase
activity, and 571 urine samples were taken for 2-nitrophenol content.
The latter test was added because a sensitive procedure for j>-nitrophenol
determination had been developed and was later published by Elliott et
al. (1960).^J  The results of the 1958 survey were summarized by stating
that only the group with the highest potential exposure to parathion,
that is the mixing plant personnel, sustained a definite decreased in
cholinesterase activity during exposure.  There was a significant excre-
tion of £-nitrophenol during the period of exposure for mixing plant
personnel, part-time ground applicators, commercial ground applicators,
aircraft application workers and workers in orchards.  Furthermore, the
excretion of j>-nitrophenol by residents near the orchard was not sig-
nificant.  They observed that j>-nitrophenol excretion was elevated in all
poisoning cases studied.

     Bick (1967) in Australia made similar observations on the blood
cholinesterase activity in orchard workers exposed to parathion and other
organophosphorus insecticides and Sevin®.  Bick collected blood samples
at the beginning of the spray season in 1962 and 5 weeks later after a
period of extensive spraying.  In 1963 he again took samples before
spraying and after spraying.  He selected 15 orchard workers who had a
marked decrease in plasma or red blood cell activity in 1962, and he
tested these workers at intervals of 4 to 5 weeks for an additional 13
months, and a final collection was made 6 months later in September of
1965.  He reported that the mean values of RBC cholinesterase activity
for the orchard workers in 1962, before and after spraying, were sig-
nificantly less than the value obtained on a control group who lives in
a metropolitan area.  After periods when no spraying activity was in-
volved, the plasma and red blood cholinesterase activity increased.  It
was Bick1s opinion that the use of the protective measures which had
been recommended by responsible authorities reduced the exposure and was
reflected by the minimal effect seen on red blood cell cholinesterase.

     An interesting study was conducted by Ganelin et al. (1964) to
determine if there were any deleterious effects on persons with respira-
tory disease that might be involved in exposure to organophosphorus com-
pounds.  This work was done in the Phoenix, Arizona, area, where it is
I/  Elliott, J. W., K. C. Walker, A. E. Penick, and W. F. Durham, "A
      Sensitive Procedure for Urinary £-Nitrophenol Determination as a
      Measure of Exposure to Parathion,11 J. Agr. Food Ghent.. 8:111
      (1960).
                                   115

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known that a large number of people with respiratory and chronic diseases
live.  They used 122 subjects, grouped into five specific groups.

     Group 1 - Nonasthmatics, no exposure to organic phosphate insecticides,

     Group 2 - Nonasthmatics, environmental exposure to organic phos-
               phate insecticides.

     Group 3 - Asthmatics, no exposure to organic phosphate insecticides.

     Group 4 - Asthmatics, environmental exposure to organic phosphate
               insecticides.

     Group 5 - Nonasthmatics, with occupational exposure to insecticides,
               which included the organic phosphate compounds.

     The unexposed control subjects lived in Phoenix, and the environ-
mental exposure groups all lived less than 500 yards from cotton fields
treated with the insecticides.  Ganelin et al. (1964) found no signifi-
cant differences between asthmatics and nonasthmatics either in the ex-
posed or unexposed groups.  The £-nitrophenol excretion values were ex-
tremely low for all persons other than those in the occupational group.

     Whereas there are a number of papers reported in the early 1950's
on the occupational hazards of the use of organophosphorus insecticides
in mixing and application by spraying, either from the ground or from
the air, there are very few reports concerning the immediate effect of
residual parathion in treated fields on workers or on establishment of
adequate reentry intervals.  Conley reported, in a scientific meeting
in 1952, an episode where a number of workers in a vineyard which had
been sprayed 33 days before with parathion became ill about 7 hr after
work began (quoted by Quinby and Lemmon, 1958).  Sixteen of the 24 de-
veloped symptoms requiring hospitalization.  As far as is known, none
had previous exposure to cholinesterase inhibitors. These workers suf-
fered from weakness, diarrhea, miosis, headaches, and nausea.  Symptoms
were relieved with 1/100 g of atropine.  There have been conflicting
reports on the development of illness of workers in picking tobacco as
related to insecticide residues. Lieben et al. (1953) recorded suspected
parathion poisoning in tobacco pickers in Connecticut.  Schaefer and
Vance (1953)—  measured parathion residues on tobacco, and stated that
\J  Schaefer, R. A., and G. M. Vance, "Exposure of Connecticut Tobacco
      Workers to Parathion," AMA Arch. Ind. Hyg. Occup. Med.. 7:193-196
      (1953).
                                   116

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few proved illnesses from skin absorption of parathion came to the atten-
tion of the Connecticut State Department of Health although there were
thousands of workers handling tobacco leaves.  Some interesting results
have been obtained by Braid and Dustan (1955)i'  on the persistence of
parathion residues on immature peaches.   They found that residues per-
sisted on the fruit for 14 to 20 days and on the leaves for approximately
2 days.  Bobb (1954)—/ found that the ha If-life  of parathion on peach
tree bark was about 2 weeks, while only  27, of the residue persisted on
the leaves after 1 week.  Quinby and Lemmon (1958) investigated para-
thion poisoning in crop workers exposed  to residues on pears, grapes,
apples, hops, and citrus fruit in 11 different locations.  Excellent de-
tail is given in this paper on the symptoms and  the types of exposure
under many different situations.  In some cases  mild poisoning has been
produced in workers thinning, picking, cultivating, and irrigating the
aforementioned crops that were treated with 1 Ib or more of parathion per
acre.  Several of the incidences of poisoning involved exposure to foliage
or fruits sprayed not more than 2 days earlier.   It is rather remarkable
that contract with pear trees, citrus trees, and grapevines caused poison-
ing as much as 12, 17 and 33 days, respectively, after application of
parathion.  These investigators noted that in the group of outbreaks one
common feature was that the foliage was  chest-high.  The main difference
in the clinical picture between poisoning which resulted from contact
with plants or from exposure during spraying and dusting was the rela-
tive mildness, the gradual onset, and the benign nature of the symptoms.

                                             3/
     As has been reported by Ware et al {1973)-  the determination of safe
reentry  intervals is influenced by a number of factors including, (1)
frequency and rate of application, (2) characteristics of the foliage,
(3) height of the foliage,  (4) density of the canopy, (5) the weather,
and (6) inherent characteristics relative to the particular pesticide
applied, i.e., persistence, toxicity, penetratability, etc.  Other
factors involved are length of exposure time, the type of clothing worn
I/  Braid, P. E., and 6. G. Dustan, "Parathion Residues on Immature
      Peaches and the Hazard in Spraying and Thinning Operations," J.
      Econ. Entomol.. 48:44-46 (1955).
2/  Bobb, M. L., "Parathion Residues on Peach Bark and Foliage," J^
      Econ. Entomol.. 47:190-191 (1954).
31  Ware, 6. W., D. P. Morgan, B. J. Estesen, W. P. Cahill, and D. M.
      Whitacre, "Establishment of Reentry Intervals for Organophosphate-
      Treated Cotton Fields Based on Human Data:  I.  Ethyl   and Methyl
      Parathion," Arch. Environ. Contain. Toxicol., 1:48-50 (1973).
                                    117

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and presence  or  absence  of  respiratory protection.  The recommended re-
entry  time  established must be  long  enough  to  give protection  to the
worker but  short enough   to be  tenable with profitable agriculture
practice.

     In  the study reported  by Ware et al. (1973) on aerial application
of a mixture  containing  0.5 Ib  of methyl parathion, 0.5 Ib of  ethyl
parathion and 2.0 Ib  of  toxaphene in 5 gal. of spray per acre.  The crop
was mature  cotton with bolls  beginning to open.  Ten minutes after ap-
plication two men entered the field  and collected samples for  30 min;
this operation was repeated at  12, 24, 48,  and 72 hr after insecticide
treatment.

     Biomedical  data  indicated  that  there was  no clinical evidence of
plasma or RBC cholinesterase  depression or  of  urinary £-nitrophenol in
either subject (man) even when the field was entered immediately after
treatment.

     Ware et  al. (1973)  reported that from  the accumulation of residues
on skin  and clothing  that an  individual can expect exposure to the fol-
lowing amounts of mixed  residues during a 30-min period at the treatment
time indicated after  treatment  of a  cotton  field with methyl and ethyl
parathion.
 Time after            Hands and            Clothing        Inhalation
treatment  (hr)        forearms  (mg)           (mg)            (mg/ml)

      0                  3.47                 18.21           1.06
     12                  1.93                 12.11           0.60
     24                  1.16                 6.57           0.36
     48                  0.60                 4.52           0.18
     72                  0.31                 2.65           0.09
     These authors (Ware et al., 1973) suggest that with cotton, reentry
can be safely made 12 to 24 hr after spraying with parathion.
                                    118

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     Outstanding summaries of the exposure of workers  to pesticides have
been made by Wolfe et al.  (1967)i/ and Hayes (1971).I/  Hayes (1971) has
brought together (based on data from Wolfe et al.,  1967), the potential
exposure of workers to ethyl and methyl parathion,  malathion, dichlorvos,
chlorthion, carbaryl and azinphos-methyl.  Information  on parathion was
shown (1) for air-blast spraying fruit orchards,  (2)air-blast spraying
orchards with concentrate,  (3) spraying orchards with high-pressure powered
handguns, and (4) spraying tomato plants with mist  from hand-operated
knapsack sprayer.  The highest exposure (respiratory)  to parathion was
for spraying orchards with high-pressure powered  handguns.   The greatest
exposure (dermal) to parathion was air-blast spraying of fruit orchards.

     Hayes (1971) expressed the thinking that, although the concentra-
tions of pesticides in working areas very often exceed threshold limit
values, the reported concentrations are not necessarily dangerous.  The
threshold limit values for industrial chemicals of  comparative toxicity
are usually higher than that for pesticides.  A statement was made by
Hayes that about 80% of the total absorption of parathion is by the dermal
route under orchard spraying conditions.  Hayes  (1971) summarized factors
influencing respiratory and dermal exposure:

     1.  Type of formulation.

     2.  The concentration of the formulation.

     3.  The method of application.

     4.  The duration of application.

     5.  The type of work.

     6.  The wind and other environmental factors.

     7.  The attitude of the workers.

As one would expect, the variations of  the exposure are wide  (Wolfe
et al, 1967); dermal exposure could range as much as 200-fold and
 \l  Wolfe, H. R., W. F. Durham., and J. F. Armstrong, "Exposure of Workers
"~   to pesticides," Arch. Environ. Health, 14:622-633 (1967).
2/  Hayes, W. J., Jr., "Studies on Exposure During the Use of Anti-
      cholinesterase pesticides,  "Bulletin of the World Health Organiza-
      tion. 44:277-288 (1971).
                                    119

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the respiratory exposure  in. the form of concentrate might range up to
300-fold.  The type of  spraying is also influential.  Spraying into
trees affords much more exposure to the operator than similar spraying
on row crops.  Wind speed is so important that some states have laws
specifying the highest  velocity for application of certain types of
herbicides.  Another environmental factor is temperature.  It has been
shown (Funckes et al.,  1963) that temperature affects the rate of absorp-
tion through the skin.

     The potential for  oral exposure from eating food items contaminated
with parathion as a result  of handling with unwashed hands was evaluated
in a study by Armstrong et  al.  (1973).!' Two situations were considered:
(1) the effect of drift during spray operations on food items carried by
workers and (2) the contamination of foods by the hands of workers who had
been exposed to treated foliage, etc. (fruit thinners).

     The results of this  study indicated that the potential exposure re-
sulting from contamination  of food items by unwashed hands is not high
under normal conditions of  apple thinning or in the application of dilute
spray solutions.  The daily intake of parathion under the conditions de-
scribed above was reported  to be below 3 mg/day.

     Higher intakes of  insecticides by hand contamination of snack items
can be expected where sprayers carry food items such as candy bars and
where concentrated formulations are being handled.

     Wolfe et al. (1967)  indicated that the morbidity of persons who are
exposed from occupational standpoint is not great because (1) the
dangerous operations only occupy a few hours a day or a week; (2) the
workers usually wear protective clothing; and (3) the absorption by
workers in the field is not comparable to exposures administered to laboratory
animals.

     Manufacturing operations - The number of studies conducted on the
relationship of the manufacturing and packaging of parathion as to industrial
hazards is limited.

     Brown and Bush (1950)^' made a study of parathion in the atmosphere of
an industrial plant which manufactured the concentrated material.
I/  Armstrong, J. F., H. R. Wolfe, S. W. Comer, and D. C. Staiff, "Oral
      Exposure of Workers to Farathion Through Contamination of Food Items,"
      Bull. Environ. Contain. Toxicol.. 10:3218-3327 (December 1973).
27  Brown, H. V., and A. F. Bush, "Parathion Inhibition of Cholinesterase,"
      Arch. Ind. Hyg. Occup. Med.. 1:833-636 (1950).
                                    120

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They placed air samplers at the sites of different operations to measure
the parathion.  In addition, the plasma and red blood cell cholinesterase
of the persons in the plant were determined.  The evaluations for the
red blood cell cholinesterase were made over a period of 1 year at
intervals of 2, 3, and 5 months.  The subjects were chemists, janitors,
utility men, engineers, supervisors, workers in mixing rooms, handymen,
and the plant superintendent.  The data indicated that they felt that a
physiological effect was produced.  Although the air samples showed a
maximum concentration of only 8 mg of parathion per 10 mj of air, they
felt that these concentrations may be potentially dangerous if breathed
over a long period of time.  Another in-plant study was made in later
years by Hartwell and Hayes (1965).±'  Using two plant sites as a test base,
these investigators compared the effectiveness of certain respiratory pro-
tection.  Plant A18 ventilation system, was found to be deficient.  Plant
B was a modern facility.  The general ventilation was considered quite
adequate, and only nontoxic dusts were handled manually.  Each formulating
plant processed phosdrin, methyl parathion, and ethyl parathion.  They
both evaluated poisoning by clinical signs as well as a depression of the
cholinesterase activity of 20% or more.  During the first year Plant A
sustained 17 cases of alleged poisoning, and depression in cholinesterase
activity of 20% was observed 41 times among 26 subjects.  This load of
toxicity led to the installation of a system to distribute uncontaminated
compressed air to workers engaged in hazardous operations.  After these
alterations no cases of poisoning occured, and depressions in cholinesterase
activity were observed only four times among 13 workers.  Plant B, which
theoretically afforded better protection, had to shut down for 10 days
because of the occurence of poisoning.  The fault was due to a compresser
that both supplied air to the operators and forced concentrates into the
mixing chamber.  When a separate compressor was used for each operation,
no cases of poisoning were observed.

     Accidents - Parathion  is one of the pesticides most frequently cited
in incidents involving accidental exposure  to pesticides.  Preliminary data
from the EPA Pesticide Accident Surveillance System  (PASS) shows  that  para-
thion is the third most frequently  cited pesticide in 1973.  Based on  an
analysis of PASS data, Osmun (1974)-' stated that  for 1972 and  1973, parathion
and/or methylparathion were connected with  78% of  the reported  episodes re-
lating to agricultural jobs, particularly those involving fields  sprayed
with pesticides for which  safe  reentry  times for workers had been set.
 I/   Hartwell, W. V., and F. R. Hayes, Jr.,  "Respiratory Exposure to Organic
       Phosphorus Insecticides," Arch. Environ. Health,  11:564-568 (1965).
 21   Osmun.  J. V.,  "PASS Information Relating  to Agriculture Jobs," Internal
       EPA Memo  to  Ed Johnson  (1 April 1974).
                                     121

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There are a number of limitations in attempting to use PASS data.  First
of all, the cause-effect relationship between the pesticide(s) cited and
the effects observed have generally not been established.  Secondly, only
data for 1972 through about January 1974 has generally been computerized
and readily available for retrieval.  Thirdly, a large portion of the
data provided to PASS comes from California (e.g., 95 of the 257 parathion
episodes involving humans, animals, plants, and area contamination in the
computerized data base).  This skewed distribution is probably a result
of the method used by California to document pesticide information.  In
addition, files on the investigations made to follow up on episodes
reported in California are not part of the PASS data base.  Information
in addition to that found on the pesticide episode reporting form was
available on only 12 of the 257 episodes involving parathion.

     On 10 June 1974, protection standards for agricultural workers in
fields treated with parathion became effective (Quarles, 1974)1/.
These standards prohibit application of parathion when unprotected
workers are in the area being treated and require that unprotected
workers not enter fields treated with pesticides for at least 48 hr.
I/  Quarles, J., "Worker Protection Standards for Agricultural Pesticides,"
      Federal Register. 39(92):16888-16891  (10 May 1974).
                                   122

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Ackermann, H., and R. Engst, "Presence of Organophosphate Insecticides
  in the Fetus," Arch. Toxikol.. 26:17-22 (1970).

Ahmed, M. K., J. E. Casida, and R. E. Nichols, "Bovine Metabolism of
  Organophosphorus Insecticides:  Significance of Rumen Fluid with
  Particular Reference to Parathion," J. Agr. Food Chem.. 6:740-746
  (1958).

Alary, J-G., and J. Brodeur, "Correlation Between the Activity of Liver
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  Pharmacol., 48:829-831 (1970).

Aldridge, W. N., "Serum Esterases, 2.  An Enzyme Hydrolysing Diethy1
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Al-Hachim, 6. M., and 6. B. Fink, "Effect of DDT or Parathion on the
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Andersen, A. A., and 0. Karlog, "Elimination of Parathion in Cows After
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  Methyl, Ministerie von Sociale Zahen En Volksgenzandheid (1964).
                                    123

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Armstrong, J. F., H. R. Wolfe, S. W. Coiner, and D. C. Staiff,  "Oral
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  Items," Bull. Environ. Contain. Toxicol., 10:321-327 (December 1973).

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Barnes, J. M., and F. A. Denz, "The Chronic Toxicity of £-Nitrophenyl
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Bass, S. W., A. J. Triolo, and J. M. Coon, "Effect of DDT on the Toxic-
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  stock," Adv. Vet. Sci.. 4:265-276 (1958).

Radeleff, R. D.,  and R.  C.  Bushland, "The Toxicity of Pesticides for Live-
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  (1958).
                                    135

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Sakai, K., and F. Matsumura, "Degradation of Certain Organophosphate
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Schaefer, R. A., and G. M. Vance, "Exposure of Connecticut Tobacco
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                                   136

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Triolo, A. J., and J. M. Coon, "Toxicologic Interactions of Chlorinated
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Tsachalinas, D., G. Logaras, and A. Paradelis, "Observations on 246
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Villeneuve, D. C., W. E. J. Phillips, and J. Syrotiuk, "Modification of
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                                    137

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Wilber, C. 6., and R. A. Morrison, "The Physiological Action of Parathion
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  (1972).
                                   138

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         SUBPART II.  C.   FATE AND SIGNIFICANCE IN THE ENVIRONMENT


                                 CONTENTS



                                                                         Page

Effects on Aquatic Organisms 	        141


  Fish	        141
    Laboratory Studies 	        141
    Field Studie	       146
Lower Aquatic Organisms	       150

    Laboratory Studies 	      150
    Field Studies	     151
Effects on Wildlife 	   157
    Laboratory Studies 	    157
    Field Studies	   161
Effects on Beneficial Insects 	   163
    Bees	163
    Parasites and Predators	165
Interactions with Lower Terrestrial Organising.       	  168


    Reviews	168
    Field Studies	169
    Laboratory Studies 	  170
                                    139

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                                                                        Page

Residues in Soil	    172


     Laboratory Studies 	   172
     Field and Combined Field-Laboratory Studies 	    179


       Short-Term Studies 	   179
       Long-Term Field Studies 	    183
       Monitoring Studies 	   185
       Summary	    188


Residues in Water	189


     Laboratory and Field Studies 	   189
     Monitoring Studies 	   193


Residues in Air	193


Residues in Nontarget Plants	195


Bioaccumulation, Biomagnification 	   196


Environmental Transport Mechanisms 	    197


References	    199
                                      140

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Effects on Aquatic Organisms

Fish -

     Laboratory studies - Acute toxicity data for parathion's effect on
fish is summarized in Table 18.  It is obvious that toxicity of parathion
varies considerably depending upon the species (see Table 19 for scientific
names of fish) and upon the method used.  The toxicities of parathion to
the natural population of fish ranges from a low of 0.047 ppm (48 hr LC50)
in bluegill to a high of 6.25 ppm (48 hr TLm) in carp.  Exposure times
used in the studies cited in Table 18 ranged from 2 hr to 1 week.  Some
of the differences in toxicity are undoubtedly due to differences in the
maturity of the fish used and in their physical condition.

     The effects of maturity on the toxicity of parathion for bluegill
can be inferred from the TLm data in Table 20.  There is a difference in
the susceptibility of young (small) bluegill compared to older (large)
bluegill; the larger fish are less susceptible to parathion poisoning.
While the difference in TLm is not great (about two times), the con-
tamination of a water system by parathion at a level below the TLm f°r
adult fish could still have a lethal effect on the immature members of
the population.

     Pickering et al.  (1962)^' have made a comparison of the toxicity
of organophosphate insecticides for bluegill and white rats (Table 21).
It would be more valid to compare fish toxicity, which is associated
with continuous contact with the pesticide through the gills, with
inhalation data for rats, which are derived through continuous expos-
ure to the respiratory tract.  Kimmerle and Lorke (1968)2' reported an
inhalation LCso for male rats to be 0.0315 mg/liter with a 4 hr
exposure time.

     The reduction in fish-brain acetylcholinesterase (AChE) activity
may be used to monitor waters for the presence of organophosphate contami-
nants although cautious interpretations should be made (Gibson et al. 1969)-'
Nevertheless, Coppage and Matthews (1974)^' state: "...AChE measure-
ments are probably the best general index of organophosphate poisoning
of fish in the environment."
.!/  Pickering, Q. H., C. Henderson, and A. E. Lemke, "The Toxicity of
      Organic Phosphorus Insecticides to Different Species of Warmwater
      Fishes." Trans. Am. Fish. Soc.. 91(2):1750184 (1962).
2j  Kimmerle, G., and D. Lorke, "Toxicology of Insecticidal Organophos-
      phates," Pflanz. Nachr. Bayer. 21:111-142 (1968).
3/  Gibson, J. R., J. L. Ludke, and D. E. Ferguson, "Sources of Error
      in the Use of Fish-Brain Acetylcholinesterase Activity as a Monitor
      for Pollution," Bull. Environ. Contain. Toxicol.. 4:17-23 (1969).
4/  Coppage, D. L., and E. Matthews, "Short-Term Effects of Organophos-
      phate Pesticides on Cholinesterases of Estuarine Fishes and Pink
      Shrimp." Bull. Environ. Contam. Toxicol.. 11:483-488 (1974).
                                    141

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                                 Table  18 .  ACUTE TOUCHY OF PARATHION TO FISH
   Fl»h toted

Fathead minnow
Fathead minnow
Bluegill
Blueglll
Bluegill
Carp
Carp
Rainbow trout
Rainbow trout
Brook  trout
Puopklnseed  sunflih
Pumpklnseed  sunflsh
Green  (unflah
Largemouth ban
Mummlchog
Tllapla
Tllapla
Striped mullet
Golden shiner
Bullhead
Mosquito fish
Rice fish
Goldfish
Gupples
  Toxlclty
calculated
   (oral)
TL50
TLj,
LC50*
"so
n»
401 Mortality
801 Mortality
SOI Mortality
"•50
TI»
U»50
"50
TI*
EC50*
"50
TL.
LC50
"50
IP-0 Mortality
501 Mortality
   Toxlclty
   measured
     (PP»)

  1.4-1.6
  2.5
  0.095
  0.047
  0.141
  3.2-6.25
   .00
   .00
   .30
   .80
  0.155-0.42
110 mg/kg
  0.155
  0.19
  0.15
  0.375
  0.60
  0.125
  0.931
 40 mg/kg
  0.19
  2.9
  2.7
  0.06
References

  a/, b/
  c/
  I/
  e/
  I/
  I/. &/
  i/
  £/
  a/, d/
  I/  "
  it
  •/
  I/
  a/
  I/
  «/
  d/
  «/
  I/
  i/
*  Because death was used as  the end point, \JC$Q, ECjg> *nd TLq, values are comparable.
a/  Pickering et al..  op. clt.  (1962).
b/  Henderson,  C.,  and Q. H.  Pickering,  "Toxlclty of  Organic  Phosphorus Insecticides to Fish,1'
~     Trans, Am. Fiih.Soc.. 87:39-51 (1958).
£/  Anon., National Water Quality Laboratory  (EPA), unpublished data  (24 May 1974).
d/  Gibson, J.  R.,  "Comparative Biochemistry  of  Parathlon Metabolism  In Three Species of Fishes,"
      Piss. Abstr.  Int.. 32i(4): 2365-B  (1971).
e/  Federal Water Pollution" Control Administration, "Water Quality Criteria," Report of the National
      Technical Advisory Committee, p. 37  (1968).
i/  Sreenlvasan, A., and  G.  K. Swamlnathan,  "Toxicity of Six Organophosphorus Insecticides to Fish,"
~     Curr. Set.. India, 36:397-398 (August 1967).
g/  Nishiuchl,  Y.,  and Y. Hashimoto, "Toxicity of Pesticides  to Some  Freshwater Organisms,"  Rev.
      Plant Protec. Res.. 2:137-139 (1969).
h/  Mulla, M. S., J. St. Amant, and L. D.  Anderson, "Evaluation of Organic Pesticides for Possible
~     Use as Fish Toxicants," Prog. Fish-Cult..  29(l):36-42 (1967).
if  Lewallen, L. L., and W. H.  Wilder, "Toxicity of Certain Organophosphorus and Carbamate
      Insecticides  to  Rainbow Trout," Mosquito News.  22(4):369-372 (1962).
i/  Wood, E. M., "The  Pathology of Pesticide  Toxicity in Fish,"  Unpublished, USDI, Columbia, Missouri.
k/  Benke, G. M., K. L. Cheever, F. E. Mirer,  and S.  D. Murphy, "Comparative Toxicity, Anticholln-
      esterase  Action  and Metabolism of  Methyl Parathlon in Sunfish and Mice," Toxtcol. Appl. Pharmacol..
      28:97-109 (1974).
I/  Lowe", J. I., P. D. Wilson,  and R. B. Davlson, "Laboratory Bioassays," Progress Report for Fiscal Year
      1969. Bureau  of  Commercial Fisheries Center for Estuarlne and Menhaden Research, Pesticides
      Field Station, Gulf Breeze, Florida, U.S.  Dept. Interior, Circular 335, pp. 20-28 (1970).
m/  Lahav, M.,  and  S.  Sarlg,  "Sensitivity  of  Pond Fish to Cotnlon (Azinphosmethyl) and Parathlon,"
      Bamldgeh. 21(3):67-74 (1970).
n/  Murphy, S.  D.,  R.  R. Lauwerys, and K.  L.  Cheever, "Comparative Antlchollnesterase Action of
      Organophosphorus Insecticides in Vertebrates,"  Toxlcol.  Appl. Pharmacol.. 12:22-35 (1968).
                                                 142

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 Table  19.   COMMON AND SCIENTIFIC NAMES OF FISH USED IN CONTROLLED
                     TOXICITY TESTS WITH PARATHION
        Common name                             Scientific name

   Fathead minnow                          Pimephales promelas
   Bluegill                                Lepomis macrochirus
   Carp                                    Cyprlnus carpio
   Rainbow trout                           Salmo gairdneri
   Brook trout                             Salvelinus fontinalis
   Green sunfish                           Lepomis cyanellus
   Pumpkinseed sunfish                     Lepomis gibbosus
   Largemouth bass                         Micropterus salmoldes
   Mummichog                               Fundulus heteroclitus
   Tilapia                                 Tilapia aurea
   Striped mullet                          Mugil cephalus
   Golden shiner                           Notemigonus crysoleucas
   Black bullhead                          Ictalurus melas
   Mosquito fish                           Gambusta affinis
   Rice fish                               Oryzias latipes
   Goldfish                                Carassius auratus
   Guppy                                   Lebistes reticulatus
   Spot                                    Leiostomus xanthurus
   Pinfish                                 Lagodon rhomboldes
      Table 20.  COMPARATIVE TOXICITY OF PARATHION'AND MALATHION
                     INSECTICIDES TO CENTRARCHIDS
Insecticide
96 hr
Bluegills
small
TL^ (ppm, AI)
Bluegills
large

Green
sunfish

Largemouth
bass
Parathion            0.065          0.14          0.42        0.19

Malathion            0.11           0.24          0.12        0.05
Data from:  Pickering et al., op. cit. (1962).
                                  143

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     Table 21.  TOXICITY OF THREE ORGANOPHOSPHATE INSECTICIDES
                  TO BLUEGILL AND WHITE RATS
                                   Bluegill                      White rats
                                   96 hr TL,n                     Oral LD$Q
Insecticide                        (mg/1)                         (me/Kg)

Parathion                           0.095                            13.0

Methyl Parathion                    1.90                             28.0

Malathion                           0.090                         1,375.0
Data from:  Pickering et al.. op. cit. (1962).

     The relationship between AChE inhibition to death of estuarine
animals was studied by Coppage and Matthew (1974).  In this study the
effect of parathion on spot and pinfish AChE activity at concentrations
of LC4Q to LCgg were determined.  When spot were exposed to parathion
at 10 ppb for 24 hr, AChE activity (brain) was reduced 88% and when
pinfish were used as the test animal the activity was reduced 90%.

     These studies appeared to Indicate that AChE activity reduced to
80% of normal was critical in short-term organophosphate poisonings.
The lethal threshold probably varies among species.

     The relationship of brain AChE inhibition to death after exposure
to parathion concentrations that killed from 40 60% of sheepshead
minnows in 2, 24, 48, and 72 hr was studied by Coppage (1972).-'  The
AChE activity was measured at 2 hr for the 2-hr lethal dose, at 6 and
24 hr for the 24-hr lethal dose, at 24 and 48 hr for the 48-hr lethal
dose and at 24, 48 and 72 hr for the 72-hr lethal dose.

     The 48- and 72-hr exposures caused AChE to fall below 17.7% of
normal for 24 hr preceding death.  The 24-hr exposure caused AChE to
fall to and remain below 17.7% for 18 hr prior to death.  Death in all
lethal exposures occurred at AChE levels ranging from 0 to 15.4% of
normal.
I/  Coppage, D.L., "Organophosphate Pesticides:  Specific Level of Brain
      AChE Inhibition Related to Death in Sheepshead Minnows," Trans.
      Am. Fish Soc.. 101:534-536 (1972).
                                    144

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     Problems that may arise by using in vitro reduction of AChE as a
measure of insecticide toxicity were demonstrated by Coppage (1971).*'
He reported that by comparing the percentage of the inhibition of
AChE with the 48-hr LDso of parathion and other organophosphates, good
correlation between the in vitro inhibition and toxicity could not be
established.  This author stated that only in vivo inhibition can be a
meaningful indicator of toxicity and that this required bioassays in
order to determine the exact relationship of AChE inhibition to concen-
tration of insecticide, length of exposure and death.

     The responses of mosquito fish which had developed a resistance to
organochlorine compounds were compared to those of naturally sensitive
fish when both groups were exposed to parathion (Chambers and Tarbrough,
1974).-'  It was shown that organochlorine-resistant populations of
mosquito fish can tolerate more parathion in the spring than in the fall
(about 1.6-fold greater).

     The poisoning effects of parathion in fish usually appear first as
erractic movements followed by the fish swimming on its side.  As the
poisoning progresses, the fish will come to the surface and gulp for
air.  In most studies the cessation of gill movement is taken to be
the time of death.

     Parathion poisoning produced lesions in the liver, kidney and
gills.  However, the liver changes were nonspecific, generalized
degenerative changes.  Characteristic liver changes in moribund fish
were swelling of parenchymal cells and congestion of the sinusoids.
The kidney lesions were apparently glomerular damage with the appearance
of proteinaceous material both in Bowman's space and in the connecting
tubules.  Pathology of the gill consisted primarily of thickening of
the epithelial layer surrounding the capillaries of the individual
lamellae.-'

     Parathion poisoning in the frog is reported to produce anemia and
leucopenia.  Increases in concentration resulted in a progressive
neutropenia and a lymphocystosis.  Clotting time was increased.
I/  Coppage, D. L., "Characterization of Fish Brain Acetylcholinesterase
      with an Automated pH Stat for Inhibition Studies," Bull. Environ.
      Contain. Toxicol.. 6:304-310 (1971).
2J  Chambers, J. E., and J. D. Yarbrough, "Parathion and Methyl Para-
      thion Toxicity to Insecticide-Resistant and Susceptible Mosquito
      Fish (Gambusia affinis)? Bull. Environ. Contain. Toxicol., 4:315-
      320 (1974).
3/  Wood, E. M. "The Pathology Of Pesticide Toxicity in Fish," Unpublished,
      U.S. Department of Interior, Columbia, Missouri.
                                      145

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      Generally toxicosis was shown by a drooping posture and  a de-
creased muscle tone; occasionally spastic paralysis occurred.

      When parathion exposure was increased to 15 ppm,  a generalized
edema resulted.  Tremors, salivation or hemorrhage was  not observed
(Kaplan, and Glaczenski, 1965).!.'

      Sanders (1970)1/ reported TL^Q values in mg/liter for 1-week-
old frog tadpoles (Pseudacris triseriata) for 24, 48, and 96 hr to
be 1.6 (0.4-3.0), 1.4 (0.91-2.8) and 1.0 (0.3-2.0), respectively.
                                                 o /
     Field studies  - Dolphin  and Peterson  (I960)—  investigated the
fish toxicity of parathion with  a view  to  its possible use  for the
control of the Clear Lake gnat  (Chaoborus  astictopus)  in Clear Lake,
Lake County, California.  Parathion was  added to Clear Lake water at
different concentrations in 5-gal aquaria  to which five test  fish each
were added.  The 24-hr LC50 of parathion to Clear  Lake bluegill (Lepomis
machochirus) was found to be  0.013 ppm.  The approximate LC^Q of para-
thion to the Clear  Lake gnat, the target insect, was 0.018  ppm.  Thus,
parathion was toxic to fish at dosages  required  for insect  control.

     In the summer  and fall of  1959,  two farm ponds were treated with
parathion by injecting a 1:10 acetone-pond water formulation  contain-
ing the required amount of technical  grade parathion from a Hudson pack
sprayer into the wake of a small boat which was  being  rowed back and
forth along the length of the pond.
I/  Kaplan, H. M., and S. S. Glaczenski, "Hematological Effects of
      Organophosphate Insecticides in the Frog (Rana pipiens),"
      Life Sci.. 4(7):1213-1219 (1965).
2/  Sanders, H. 0., "Pesticide Toxicities to Tadpoles of the Western
      Chorus Frog Pseudacris triseriata and Fowler's Toad Bufo
      woodhousii fowlert, Copeia. No. 2, pp. 246-251 (1970).
37  Dolphin, R. E., and R. N. Peterson, "Developments in the Research
      and Control Program of the Clear Lake Gnat Chaoborus astictopus,
      D.&S.," Proc. and Papers of Twenty-Eighth Ann. Conf., California
      Mosquito Control Assoc., pp. 90-94 (1960).
                                   146

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     One pond was treated with parathion at a dilution rate of 1:60
million (0.017 ppm).  Four days after treatment, 100% mortality of
Clear Lake gnats was achieved.  There was heavy fish mortality 2 weeks
after treatment, including 388 green sunfish, 11 bluegill, and 12 brown
bullhead.

     A second farm pond was treated in the same manner with parathion
at the rate of 1:100 million (0.01 ppm).  In this case, Clear Lake gnat
mortality 4 days after treatment was 45%.  Two weeks after treatment,
four dead bluegill were observed.  Thus, the results of the pond tests
were in good agreement with the aquarium tests.

     Nicholson et al.  (1962)i/ and Grzenda et al. (1962)2/ described
the results of insecticide contamination of a 2.7-acre pond draining a
40-acre watershed where peaches were the principal crop.  Parathion was
used for pest control in the watershed from 11 April to 1 August 1960.
Before insecticide use started in 1960, parathion residues of 1.7 ppm
were present in a surface soil sample, indicating carry-over of para-
thion residues in the soil from the preceding season.  Surface soil
samples taken during and after the parathion spray season in 1960 con-
tained from 0.23 to 1.39 ppm of parathion.  Prior to insecticide use
in 1960, pond bottom mud samples contained 1.9 ppm of parathion, while
two water samples contained 0.02 ppb.  Most of the parathion present in
the pond immediately before the 1960 spray season apparently entered the
pond adsorbed on soil during a period of accelerated soil erosion in
March of 1960.

     The parathion content of the pond water increased as the spraying
season progressed, while the parathion content of pond mud decreased,
presumably due to decomposition of existing residues and slower soil
erosion.  Populations of fish, zooplankton, aquatic insects and Oligochaeta
were unaffected by the parathion residues in the pond water and mud.
However, there was a significant reduction in the numbers of immature
aquatic insects.  Bluegills that normally feed primarily on immature
chironomids fed almost entirely on planktonic Crustacea when the insect
crop became severely reduced.
 I/' Nicholson, H. P., H. J. Webb, G. J. Lauer, R. E. O'Brien, A. R.
      Grzenda, and D. W. Shanklin, "Insecticide Contamination in a Farm
      Pond.  Part I - Origin and Duration," Trans. Am. Fish.Soc., 91(2):
      213-221  (1962).
 2_/  Grzenda, A. R., G. J. Lauer, and H. P. Nicholson, "Insecticide Con-
      tamination in a Farm Pond  Part II - Biological Effects," Trans.
      Am. Fish.Soc.. 91(2):213-221 (1962).
                                  147

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     The amounts of parathion found In the pond water (0.01 to 1.22 ppb)
were well below known levels of acute toxicity to fish.  The study demon-
strates that bluegill populations can survive chronic exposure to para-
thion in the range of 0.01 to 1.22 ppb for at least 6 months without
detectable adverse effects.  The fish in this field study may actually
have been exposed more or less continuously to low levels of parathion
for at least 17 months.

     Mulla et al. (1963)17 investigated the toxicity of parathion and
other insecticides to some aquatic wildlife species including the mosquito
fish (Gambusia affinis) and the aquatic larval stages of the bullfrog
(Rana catesbelana), the Western toad  (Bufo boreas) and Hammond's spade-
foot toad (Scaphiopus hammondi).  The toxicants were applied to 1/16-acre
field ponds at a volume of 8 gal/acre as aqueous sprays prepared from
emulsion concentrates.  At the rate of 0.1 Ib Al/acre, parathion pro-
duced 18% mortality of mosquito fish 1 day after treatment.  At the rate
of 0.4 Ib Al/acre, mosquito fish mortality was 96% when the fish were
exposed 1 day after treatment, 32% when exposed after 2 days, and 8% when
exposed after 3 days.  The same application rates of parathion were non-
toxic to the tadpoles when these were exposed to the contaminated water
for 24 hr.
                         2 /
     Miller et al. (1966)—  studied the water translocation of parathion
and its subsequent occurrence in fish and mussels in a simulated cran-
berry bog in the greenhouse.  35S-labeled parathion was applied at the
rate of 1 Ib Al/acre to the model bog.  The bog was flooded 24 hr after
application, and the water was left on for 4 hr, simulating a frost
protection flooding.  Estuarine fish (Fundulus heteroclitus) and fresh-
water mussels (Elliptic complanatus) were then exposed to the contam-
inated water in aquaria.  Specimens were analyzed periodically.

     The majority of the parathion originally present disappeared from
the water within 144 hr.  During this time, three labeled parathion
degradation products were encountered.  Of 60 fish present in the aquarium,
only 12 were alive after the first 24 hr.  The parathion concentration
in the aquarium declined from 0.07 to 0.02 ppm during this period.
After 48 hr, three of the remaining fish showed symptoms of poisoning.
II  Mulla, M. S., L. W. Isaak, and H. Axelrod, "Field Studies on the
      Effects of Insecticides on Some Aquatic Wildlife Species," J._
      Econ. Entomol., 56(2):184-188 (1963).
2_/  Miller, C. W.,B. M. Zuckerman, and A. J. Charig, "Water Transloca-
      tion of Diazinon-  C and Parathion-35S Off a Model Cranberry Bog
      and Subsequent Occurrence in Fish and Mussels," Trans. Am. Fish.
      Soc., 95:345-349 (1966).

                                  148

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On analysis, these specimens showed an accumulation of parathion to 2.1
ppm, while the surrounding aquarium water at this time analyzed 0.01
ppm parathion.  Mussels also accumulated parathion, but to a lesser
degree than the fish.

     Holland et al. (1967)i/ employed a fish brain acetylcholinesterase
test to monitor pollution by organophosphorus pesticides along the
Atlantic and Gulf coasts.  Seven laboratories cooperated by sending
fish from their areas periodically for AChE assay.  A total of 93 sam-
ples of spot (Leiostomus xanthurus) and sheepshead minnows (Cyprinodon
variegatus) from 43 stations were analyzed.  Low AChE activity was
found in 17 samples (18.3%), but 13 of these were from only two areas.
Fish that showed low AChE activity (73 to 88% of normal) from South
Carolina came from the vicinity of the Ashley River near Charleston.
This river receives wastes from plants producing a variety of organo-
phosphate chemicals.  Fish from the Galveston area with low enzyme
activity (75 to 847. of normal) generally came from stations along the
eastern edge of Trinity Bay.  The authors did not ascertain which organo-
phosphate insecticides may have been responsible for the observed fish
brain AChE depression.

     The Environmental Protection Agency's Gulf Breeze Environmental
Research Laboratory recently analyzed samples of whole fish and of fish
organs collected by the Texas Parks and Wildlife Department at different
points in Texas for residues of parathion and other pesticides.  Para-
thion residues found ranged from 21 to 170 ppb, wet weight.  The para-
thion residue levels were generally much lower than residues of organo-
chlorine pesticides found in the same specimens.

     The Water Quality Criteria Data Book. Vol 3 (Battelle Columbus,
             ._  »   j _ _ —rV^™^«i«—i       ___...
1971) — a summary review of the effects of commercial chemical products
on aquatic organisms, includes references to two further reports on
parathion fish toxicity.  When parathion was applied for the control of
mosquito larvae to a lake in Salt Lake County, Utah, at the rate of
0.35 Ib Al/acre, there were no fish losses, and no adverse effects were
observed on mammals, birds, reptiles, and amphibians.  Invertebrates
were not affected uniformly.  Crustaceans and larvae of the insect
family Ephydridae were not harmed, but spiders and aquatic insects
other than Ephydridae were harmed  in various degrees.  Aquatic beetles
were affected more seriously than  other insects, except mosquito larvae.
 I/  Holland,  H. T.,  D.  L.  Coppage,  and  P. A. Butler, "Use  of Fish Brain
      Acetylcholinesterase to Monitor Pollution  by  Organophosphorus
      Pesticides," Bull. Environ. Contain. Toxicol.. 2(3):156-162 (1967).
 2_/  Battelle's  Columbus Laboratories, "Effects of Chemicals on Aquatic Life,"
      'Water Quality Criteria  Data Book, Vol. 3:B167-B186, Environmental
      Protection  Agency (1971).

                                   149

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     Mulla and Isaak (1961)!'  treated ponds  in the BakersfieId,  California,
 area with  parathion from a 50% emulsifiable  concentrate.  At  0.1 Ib AI/
 acre,  22%  mortality of mosquito fish  (Gambusia affinis) occurred in 24 hr.
 At  0.4 Ib  parathion Al/acre,  there was 92% mortality  of the fish in 24 hr.
 In  these field tests,  the fish were exposed  in cages  placed in the ponds.

     The Federal  Water Pollution Control Administration's "Water Quality
 Criteria," (1968)  includes parathion  in "Pesticide Group A,"  defined as
 chemicals  that are acutely toxic to shrimp at  concentrations  of  5 ug/liter
 and less.   On the assumption  that 1/100 of this level represents a
 reasonable safety factor,  it  is recommended  that environmental levels
 of  these substances not  be permitted  to rise above 50 ng/liter of water.
 This level is so  low that the pesticides in  this category (including
 parathion)  could  not be  applied directly in  or near the marine habitat
 without danger of causing damage. The 48-hr TI^ of parathion to shrimp
 is  listed  at  1.0  ug/liter.  Shrimp  vere selected as  the test organism
 because they  are  among the most sensitive  marine organisms in regard to
 their  reaction to chemicals.

 Lower  Aquatic Organisms  - For purposes of  this review,  "lower aquatic
 organisms"  are defined to include primary  producers (phytoplankton,
 attached algae, moss,  and vascular plants);  consumers (protozoa,
 rotifers,  and Crustacea);  benthic invertebrates (annelids, insects,
 Crustacea,  and mollusca);  decomposers (fungi and bacteria).

     Laboratory studies  - The aquatic species  other than fish and frogs
 which  have  been studied  under controlled conditions are few in number.
 Lowe et al. (1970)  studied the effect of parathion on shrimp  (Penaeus
 duorarum),  and oysters (Crassostrea virginica).   They found that a
 48-hr  ECejQ  was obtained  with  juvenile shrimp at a parathion concentra-
 tion of 0.0002 ppm,  and  that  oyster shell  growth was  decreased 22 percent at
 1.0 ppm in  a  96-hr test.  Naqvi and Ferguson (1970)1' found that the
 LD50 (24 hr)  for  freshwater shrimp (Palaemonetes kadiakensis) was 0.0082
 ppm.
If  Mulla, M. S., and L. W. Isaak, "Field Studies on the Toxicity of
      Insecticides to the Mosquito Fish,  Gambusia affinis,"  J. Econ.
      Entomol., 54(6)-.1237-1242 (1961).
2_f  Naqvi, S. M., and D. E. Ferguson, "Levels of Insecticides Resistance
      in Freshwater Shrimp, Palaemonetes kadiakensis,"  Trans. Am. Fish.
      Soc., 99:697 (1970).
                                   150

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     These data also indicate that parathion contamination of streams
and other aquatic habitats at levels well below that having a direct
toxic effect on fish can still have an indirect effect by destroying
organisms in the food chain.

     Lowe et al. (1971)i^ performed a study in which oysters were grown
from juvenile to  sexual  maturity in seawater polluted with 1 ppb para-
thion.  A significant difference between the weights of treated and of
the untreated controls was not found.

     Field studies - The Federal Water Pollution Control Administration's
"Water Quality Criteria" (1968) lists the 48-hr Tl^ values of parathion
to the stonefly (Pteronarcys californica) and to Daphnia pulex as 11 and
0.4 ug/liter, respectively.  Parathion ranks intermediate among the insecti-
cides included in this listing in regard to its toxicity to these two
aquatic organisms.

     Further data on the toxicity of parathion to Daphnia pulex and to
other zooplankton organisms, and to benthic invertebrates are summarized
in Tables 22  and  231  The immobilization values (EC^Q) of parathion to
the zooplankton species range from 0.37 to 0.8 ppb.  The LC50 values of
parathion to several species of stoneflies, caddisflies and mayflies,
and to one species each of amphipods and freshwater shrimp varied con-
siderably, depending upon the species and the experimental conditions
such as temperature and length of exposure.  Parathion was considerably
more toxic to most of these species than, for instance, malathion.  How-
ever, it was less toxic than malathion to the amphipod (Gammarus lacustris).
                         2 /
     Ware and Roan (1971)—  reviewed the literature on the interaction
of pesticides with aquatic microorganism and plankton.  The data cited
from several original research papers in a brief section dealing with
organophosphate insecticides again confirm that parathion, along with
other organic phosphates, is subject to adsorption and degradation by
such organisms as yeasts (Torulopsis utilis), bacteria (Pseudomonas
fluorescens. Thiobacillus thiooxidans, Bacillus subtilis), and green
algae (Chlorella pyrenoldosa).
I/  Lowe, J. I., P. D. Wilson, and A. J. Wilson, "Chronic Exposure of
      Oysters to DDT, Toxaphene and Parathion," Proc. Nat. Shellfish
      Assoc., 61:71-79 (1971).
2/  Ware, G. W., and C. C. Roan, "Interaction of Pesticides with
      Aquatic Microorganisms and Plankton," Residue Reviews, 33:15-45
      (1971).
                                   151

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                Table  22.  EC5Q (IMMOBILIZATION)  VALUES (ppb)  OF THREE
                     ORGANOPHOSPHATE INSECTICIDES  TO ZOOPLANKTON
                Temperature   Time                          Methyl
    Species       (°F)	   (hr)  Malathlon  Parathion  parathlon   Reference

 Daphnla pulex      21°C       48     2                                  a/
                               48                0.76       LC50         W
                    60         48     1.8        0.6                     c/
                    60         48     1.8                                d/

 Daphnia magna      68         24     0.9        0.8                     c/
                    68         48                           4.8          d/
                    68         50     0.9        0.8                     c/
                    20°C       50     0.9        0.8                     I/

 Daphnla
   carlnata         78         64     0.2        0.5                     fj

 Simocephalus       60         48     3.5        0.37                    £/
   serrulatus       70         48     6.2        0.47                    c/
 Source:   Li, M.,  and R. A. Fleck, "The Effects of Agricultural Pesticides in
            the Aquatic Environment, Irrigated Croplands, San Joaquin Valley,"
            Pesticide Study Series   - 6, Environmental Protection Agency,
            Office of Water Programs, Applied Technology Division, Rural Waste
            Branch TS-00-72-05, 268 pp. (1972).
 a/  Cope, 0. B.,  "Contamination of the Freshwater Ecosystem by Pesticides,"
       J.  Appl. Ecol., 3 (Suppl):33-44 (A special issue on Pesticides in the
       Environment and Their Effects on Wildlife) (1966). (In:   Li and Fleck,
       1972.)
 b_/  Priester, L.  E., "The Accumulation in Metabolism of DDT,  Parathion and
       Endrin by Aquatic Food-Chain Organisms," Ph.D. Thesis,  Clemson Univer-
       sity (1965).  (In:   Li and Fleck, 1972.)
 c/  Sanders, H. 0.,  and 0. B. Cope, "Toxicities of Several Pesticides to Two
 ~~     Species of  Cladocerans," Trans. Am. Fish.Soc.. 95(2):165-169 (1966).
d/  Federal Water Pollution Control Administration,  Water Quality Criteria,
~     Report of the National Technical Advisory Committee, p.  37 (1968).
 e/  Anderson,  B.C.,  "The Toxicity of Organic  Insecticides to Daphnia."  In:
"~     Transactions of the Second Seminar on Biological Problems in Water
      Pollution,  Cincinnati,  Ohio,  U.S.  Public Health Service, pp.  94-95(1959).
      (In:   Li and Fleck,  1972.)
 f/  Matida,  Y., and  N.  Kawasaki,  "Study on the Toxicity of Agricultural  Control
"~     Chemicals in Relation to Freshwater Fisheries  Management," No.  2 Toxicity
      of  Agricultural Insecticides  to Daphnia  carinata, King, Bull. Freshwater
      Fish Res. Lab., Tokyo 8:1-6 (1958).   (In:   Li  and Fleck, 1972.)

                                         152

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Table  23.  LC5Q VALUES (ppb)  OF  THREE  ORGANOPHOSPHATE
       INSECTICIDES TO BENTHIC INVERTEBRATES

Species
Stone files
Pteronarcys caltfornlca













Acroneurla paciftca








Pteronarcella badla
^^^•••M^^^^^^^^^^B ^H^^H^^B



Claassenla sabulosa


Caddlsflles
Arctopsyche grandls
Hydropsyche callfornlca
Temperature
CO

15.5
15.5
21.0
48-50'F
11-12
11-12
11-12
15.5
12.8
12.8
12.8
12.8
12.8
12.8
11-12
11-12
11-12
12.8
12.8
12.8
12.8
12.8
12.8
15.5
15.5
48-50'F
15.5
15.5
15.5
15.5

51-54°F
51-54eF
Time (hr)
(* - days)

24
48
48
48
48
72
96
96
5*
10*
15*
20*
25*
30*
48
72
96
5*
10*
15*
20*
25*
30*
24
48
48
96
24
48
96

96
96

Malathlon

35
20
21

180
72.5
50.0
10


45.0
24.0
15.5
8.8
12
16.0
7.0
7.7
5.1
3.3
3.2
2.4
0.78
10
60
6
1.1
13
6.0
2.8

32
22.5

Parathion

28
11

11
75
32.0
32.0
5.4
36.0
2.7
2.2
2.2
2.2
2.2
6
2.9
2.8
0.93
0.46
0.45
0.44
0.44
0.44
8.0
5.6

4.2
8.8
3.5
1.5

7
0.43
Methyl

parathlon Reference

«/
a/
b/
1l
d/
d/
d/,
a/
7/
f/
f/
f/
f/
I/
d/
d/
d/,
f/
11
£/
f/
f/
I/
a/
I/
b/
a/
a/

a/

e/
e/







e/









e/
















                   153

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                                                Table 23.  (Continued)
                             Temperature
                                CC)
             Time  (ht)
             (* -  days)
           Halathion
          Parathion
           Methyl
         parathion
                                                 Reference
Mayflies
  Ephemerella grandis

  Baetla  so.

Amphipods
  GanmaruB  lacustris
48-50°F

  21
  70° F
  70'F
  60*F
  70»F
  59°F
96

48
24
48
48
48
96
100

  6
  3.8
  1.8
  1.8
  1.0
  1.62
12
 6.0
 6
 3.5
12.8
                        e/

                        b/
                                                                                                  c/
                                                                                                  It
                                                                                                  e/
Freshwater shrimp
  Palaemonetes radlakensis

Crayfish
  Procambarus clarkl
21-27
21-27
16-32
16-32
16-32
24
24
24
48
72
               6.6
              11.8
             2.5
            23.3
                                                                                      50
                                                                                      40
                                                                                      40
h/
W
                                      i/
                                      I/
                                      i/
Source:  Li and Fleck, op. cit. (1972).
a/  Sanders, H. 0. and 0. B. Cope, "The Relative Toxicities of Several Pesticides to Naiads of
      Three Species of Stoneflies," Limnology and Oceanography. 13(1):112-117 (1968)
b/  Cope, 0. B., op. clt., (1966).
£/  FWPCA, op. cit., (1968).
A/  Jensen, L. D. and A. R. Gaufin, "Effects of Ten Organic Insecticides on Two Species of Stonefly
      Naiads," Trans, Am. Fish Soc.. 93:27-34 (1964a).
e/  Gaufin, A. R., L. D. Jensen  A. V. Nebeker, T. Nelson, and R. W. Teel, "The Toxicity of Ten
      Organic Insecticides to Various Aquatic Invertebrates," Water Sewage Works. 12:276-79 (1965).
      (In:  Li and Fleck, 1972.)
if  Jensen, L. D. and A. R. Gaufin, "Long-Term Effects of Organic Insecticides on Two Species of
      Stonefly Naiads," Trans. Am. Fish Soc.. 93:357-63 (1964b).  (In:   Li and Fleck, 1972.)
£/  Sanders, H. 0., "Toxicity of Pesticides to the Crustacean Cannnarus lacustris." Technical Papers
      No. 25 pp. 18, United States Department of the Interior Fish and Wildlife Service (1969).
h/  Nagvl, S. M., and D. E. Ferguson, "Levels of Insecticide Resistance in Freshwater Shrimp,
      Palaemonetes kadiakensis."  Trans. Am. Fish Soc.. 99:696-99 (1970).  (In:   LI and Fleck,
      1972.)
if  Muncy, R. J., and A. D. Oliver, Jr., "Toxicity of Ten Insecticides to the Red Crawfish,
      Procambarus clarkl (Girard)," Trans. Am. Fish Soc.. 92:428-31 (1963).  (In:  Li and Fleck,
      1972.)
                                                         154

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     The observations by Nicholson et al.   (1962) and Grzenda  et  al.
 (1962) on  the effects of parathion contamination in a farm  pond drain-
 ing  a 40-acre watershed grown to peaches treated with parathion have
 been described in greater detail elsewhere  in this subsection  (p.139).
 Based on their careful, comprehensive studies under field conditions
 representative of a real-life situation, these authors reported that
 "the fish,  zooplankton, aquatic insect , and Oligochaeta populations
 appeared to be unaffected by parathion residues in pond water  and mud.
 However, there was a significant reduction  in immature aquatic insect
 numbers associated with insecticide use.  The data indicate this was
 caused indirectly by mortality in the adult populations resulting from
 exposure to parathion residues in the watershed.  Zooplankton  were not
 utilized as food by bluegills when Immature chironomids were relatively
 abundant.   However, when the insect standing crop became severely re-
 duced, the fish fed almost entirely on planktonic Crustacea. "

     The studies by Mulla et al.  (1963) also described in  greater de-
 tail above (see p.110) included observation on the effects  of  parathion
 on tadpoles of three species of amphibia, i.e., the bullfrog (Rana
 catesbeiana), the Western toad (Bufo boreas), and Hammond's spadefoot
 toad (Scaphiopus hammondi).  Parathion applied to 1/16-acre field ponds
 at rates of 0.1 and 0.4 Ib Al/acre did not  produce mortality when the
 tadpoles were exposed to the contaminated water for periods of 24 hr.

     A number of further studies, in addition to those summarized in
 Tables 22  and  23 , deal with interactions between parathion and aquatic
 organisms  in isolated systems under laboratory conditions.

     Zuckerman et al. (1970)1'  found that the alga Chlorella pyrenoidosa
proteose degraded parathion in axenic cultures incubated for 7 days  at
20°C.
JL/  Zuckerman, B. M., K. Deubert, M. Mackiewicz, and H. Gunner, "Studies
      on the Biodegradation of Parathion," Plant Soil 33(2):273-81 (1970)
                                    155

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      Moore (1970)-'  and Poorman (1973)-^ investigated  the  effects of
 parathion on growth  and survival of Euglena gracilis,  a  species which
 they describe as a "photosynthetic microorganism,"   along  with Kortus
 et al.  (1971)-'  ("aquatic alga"),  while Gregory et  al. (1969)4-/ con-
 sider E^ gracilis to be a flagellate.

      In Moore's  tests,  parathion inhibited the  growth  rate of E. gracilis
 only at the highest  rate tested, 1.2 ppm.   In the presence of 0.01 M
 glucose, 10 ppm  of parathion did not affect the respiration rate of
 E^ gracilis over a period of 80 min.

      Poorman found that parathion at 50 and 100 ppm depressed the growth
 rate of E^ gracilis  only to a small extent during a 24-hr  exposure.
 When the organism was exposed to parathion for  7 days, there was con-
 siderable growth stimulation as compared to untreated  controls.  These
 results indicate that parathion is not  likely to adversely affect £._
 gracilis under field conditions.

      Gregory et  al.  (1969)  found that Euglena gracilis ("a flagellate"),
 two species of algae,  and two species of ciliates,  maintained on cul-
 ture media at 26eC in an environmental  chamber  under continuous illumi-
 nation,  concentrated parathion 50 to 116  times when exposed to 1 ppm
 w/v of  the insecticide  for 7 days.   The supernatant liquids in the cul-
 tures contained  only small amounts of parathion.  The  authors attribute
 this to three possible  reasons,  i.e., adsorption by the  living organism,
 sorption by nonliving materials, and/or codistillation with water.

                                                32
      Kortus et al. (1971)  studied  the uptake of  P-labeled parathion
 by Euglena gracilis  maintained under light at 28°C.  Parathion uptake
 was determined at frequent intervals between 1  and  180 min.  The maxi-
 mum uptake of parathion (69%)  occurred  immediately  after addition of
 the pesticide.   The  activity decreased  precipitously during the follow-
 ing 15  min  and  continued to drop  at a  slower pace  after that time.
I/ Moore, R. B., "Effects of  Pesticides on Growth and Survival of
     Euglena gracilis Z.," Bull. Environ. Contarn. Toxicol., 5(3):226-230
     (1970).
2/ Poorman, A. E., "Effects of Pesticides on Euglena gracilis I.
     Growth Studies," Bui L Environ. Contam. Toxicol., 10(1)-.25-28  (1973).
3_/ Kortus, J., P. Macuch, J. Mayer, K. Durcek, and V. Krcmery, "Uptake
     of 32-P-Parathion and 32-P Imidan," J. Hyg. Epidemiol. Microbiol.
     Immunol.. (Prague) 15(1):101-103 (1971).
4/ Gregory, W. W., Jr., J. K. Reed, and L. E. Priester, Jr., "Accumula-
     tion of Parathion and DDT by Some Algae and Protozoa," J. Protozool.,
     16(1):69-71 (1969).
                                   156

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     The data reviewed In this section indicate  that parathion is
extremely toxi<5 to aquatic insects, highly toxic to the lower aquatic
fauna, and relatively nontoxic to the lower aquatic flora.  A number
of aquatic microorganisms degrade parathion.  Many of these organisms
also preferentially sorb and thus accumulate parathion from aqueous
media.  This sorption process may be independent of life processes;
sorption rates of live and dead organisms showed little differences.

Effects on Wildlife

Laboratory Studies - Most birds on which controlled experimentation
has been done are those which are either important as game animals
or are considered nuisances.  (Keith and Mulla, 1966;—  Tucker and
Haegele, 1971;!/ Schafer et al., 1973;!/ Rudd and Genelly, 1956;£/
Heath et al., 1972-/). The use of pesticides in the field noticeably
affects songbirds.

     The results of the controlled experiments appear to indicate that
while the LDcg values for toxicity of parathion range from 1 mg/kg to
about 24 mg/kg depending on species, with two exceptions, the LD^Q values
were in the range of 1 mg/kg to 5.95 mg/kg (Table 24).  The common and
scientific names of the avian species are shown in Table 25.   With game
birds the results recorded in the table indicate that when the species
(mallard, pheasant, partridge (Chukar), quail (Japanese)) are ranked from
most sensitive to least sensitive, the mallard duck is most sensitive
(LD5Q 1 to 2.13 mg/kg) to parathion, and the Chukar partridge is least
sensitive (U>5o 24.0 mg/kg) to parathion intoxication.
I/ Keith, J. 0., and M. S. Mulla,  "Relative toxicity of Five Organophosphorous
     Mosquito Larvicides to Ducks," J. Wildlife Manae.. 30(3):553-563
     (1966).
2_/ Tucker, R. K., and M. A. Haegele, "Comparative Acute Oral Toxicity
     of Pesticides to Six Species of Birds," Toxicol. Appl. Phannacol.,
     20:57-65 (1971).
3/ Schafer, E.  W. , R. B. Brunton, N. F. Lockyer, and I.  W.  DeGrazio,
     "Comparative Toxicity of 17 Pesticides to the Quelea, House Sparrow,
     and Red-Winged Blackbird," Toxicol. Appl. Phannacol.. 26:154-157
     (1973).
4/ Rudd, R. L., and R. E. Genelly, Pesticides;  Their Use and Toxicity
     in Relation to Wildlife. State of California Department of Fish
     and Game, Game Bull. No. 7, pp. 108-113 (1956).
5/ Heath, R. G., J. W. Spann, E. F. Hill, and J. F.  Kreitzer,  "Comparative
     Dietary Toxicities of Pesticides to Birds," Bureau of Sport Fish-
     eries and Wildlife, Special Scientific Report, Wildlife No. 152
     (February 1972).

                                  157

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       Table  24.  ACUTE TOXICITY OF PARATHION TO AVIAN SPECIES
                                LD50 (rag/kg)
                            Oral          Dermal         Reference
Mallard ducks 1.9, 2.13
Pheasant 12.4
Chukar partridge 24.0
Japanese quail 5.95
Pigeon 2.52
House sparrow 1.3, 3.36 1.8
Quelea 1.8 1.8
Red-winged blackbird 2.4
Starling 5.6
£/ Keith and Mulla, op. cit. (1966).
b_/ Tucker and Haegele, op. cit. (1971).
£/ Schafer et al., op. cit. (1973).

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     The information on dermal toxicity for wild birds Is limited; only
one paper was found (Schafer et al., 1973).  These investigators studied
the oral and dermal toxicity of 17 chemicals on Quelea, the house
sparrow, and on the red-winged blackbird.  The acute oral and dermal
LD50 values for Quelea exposed to parathion were 1.8 mg/kg and 1.8 tng/kg,
respectively.  The acute oral and dermal LD5o values for the house spar-
row were 1.3 mg/kg and 1.8 mg/kg, respectively.

     While oral toxicity values are important and laboratory measure-
ments of lethality are basic in predicting the immediate impact of a
pesticide on the environment, measurements of dermal toxicity would
appear to be equally if not more important, in that wildlife mortality
has been reported by some to occur chiefly through contact with foliage
(Rudd and Genelly, 1956).  However, based on the limited amount of data
shown in Table 24, there is little difference between  the oral and dermal
LDcQ values.

     The toxic effect of feeding parathion to four species of birds was
studied by Heath et al.  (1972).  These birds were at least 9 days old
before administration of the diets carrying the chemical.  Data from
this study are summarized in Table 26.
                Table  26.  AVIAN DIETARY TOXICITY  (8 Days)
                                 LC50 in feed (ppm) (95% conf.  limits)
                             Methyl Parathion         Parathion
     Bobwhite  quail              90 (73-111)            194  (150-245)
     Japanese  quail              46 (38-55)              44  (36-53)
     Pheasant                    116 (101-134)           365  (316-420)
     Mallard                     682 (541-892)           275  (183-373)
 Data of Heath et al.,  op.  cit.  (1972)
     The Japanese  quail  were more  susceptible  than bobwhlte quail,
 pheasant or mallard ducks  to parathion poisoning.  It  is interesting
 to note that it  required nearly five times  as  much parathion to kill
 the bobwhite species as  it did  to  kill the  Japanese quail.
                                  159

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      One  of  the  difficulties  in  fully  assessing the hazard potential
 for wild  birds from  laboratory studies is emphasized by the statement
 of Heath  et  al.  (1972):   "our particular interest, however, was in
 dietary toxicity because  ingestion  is  undoubtedly the predominant route
 of exposure  in wild  species." This statement  is in opposition to that
 of Rudd and  Genelly  (1956):   "Wildlife mortality occurs chiefly through
 contact with foliage."  Regardless  of  the most probable route of entry
 for parathion in wild birds,  the age of the birds at the time of expo-
 sure  has  a decided influence  on  the outcome of the ocposure.

      Ducks from  36 hr of  age  to  6 months of age have been used to deter-
 mine  the  relative toxicity of parathion for birds  in these different
 age groups.   The results  of this study by Hudson et al. (1972)!/ are
 shown in  Table 27.
               Table   27.  EFFECT OF AGE ON PARATHION
                     TOXICITY  IN MALLARD DUCKS*/
             Approximate
             age of ducks                   (mg/kg)

                 36 hr                      1.65
                  7 days                    1.44
                 30 days                    1.65
                  6 months                  2.34
a/  Data from Hudson et al., op. cit.  (1972).
     The lethality does not appear to change between 36-hr ducklings
(LD5Q 1.65 mg/kg) and 1-month-old birds.  However, as the ducks mature,
they become  less  susceptible to parathion intoxication (11)50 2'3^ m8/k8~~
6 months).  This  is in agreement with the findings of Brodeur and DuBois
(1963),—  who concluded that young rats were almost always more suscepti-
ble to anticholinesterase insecticides than older animals.
I/  Hudson, R. H., R. K. Tucker, and M. A. Haegele, "Effect of Age on
      Sensitivity:  Acute Oral Toxicity of 14 Pesticides to Mallard
      Ducks of Several Ages," Toxicol. Appl. Pharmacol.. 22:556-561
      (1972).
2/  Brodeur, J., and K. P. DuBois, "Comparison of Acute Toxicity of
      Anticholinesterase Insecticides to Weanling and Adult Male Rats,"
      Proc. Soc. Exp. Biol. Med.. 114(2):509-511 (November 1963).

                                   160

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     Although bradycardia is generally reported In parathion poisoning
in mammals, tachycardia is found to be a more consistent response to
parathion poisoning with avian species such as quail and ducks.  After
tachycardia commenced, the respiratory rate increased and remained high
until death occurred.  In both mallards and quail a small but consistent
rise occurs in the hematocrit (see Table 28).  It was observed that
parathion poisoning did not significantly alter the blood pressure in
the two avian species (McFarland and Lacy, 1968).!/
          Table 28.  EFFECTS OF INTRAVENOUS INJECTIONS OF
            PARATHION ON HEMATOCRIT OF DUCKS AND QUAIl£'
                            Mallard ducks (36)^   Japanese quail (46)
        Hematocrit          Males     Females      Males      Females

Before parathion exposure    48.2       47.3        47.6        45.1

After parathion exposure     51.8       50.5        50.8        47.6
a/  Data from McFarland and Lacy, op. cit. (1968).
b/  Number of birds.
     The birds mentioned in Table   were given intravenous injections as
follows:  mallards, 0.61 to 1.70 mg/kg; quail 3.9 to 5.7 mg/kg.

Field Studies - Robel et al. (1972)—' reported on the effects of para-
thion and other insecticides on populations of wild rodents in Kansas,
based on observations made from 1965 to 1969.  The study was conducted
on two sites in Ellis County, Kansas, in a newly created irrigation
district that had not been intensively cultivated prior to 1965.  No
insecticidal residues were found in samples of water, soil, plants,
or animals collected from the study sites prior to initiation of the
study in 1965.  Parathion was applied to one field (the second field
I/  McFarland, L. Z., and P. B. Lacy, "Acute Anticholinesterase Toxicity
      in Ducks and Japanese Quail," Toxicol. Appl. Pharmacol., 12:105-
      114 (1968).
2/  Robel, R. J., C. D. Stalling, M. E. Westfahl, and A. M. Kadoum,
      "Effects of Insecticides on Populations of Rodents in Kansas -
      1965-69,"  Pest. Monit. J.» 6(2):115-121 (September 1972).
                                    161

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 served as an untreated control)  at recommended and commonly used rates of
 application of 0.38,  1.4,  0.79,  and 1.01 Ib Al/acre in  1965,  1966,  1967,  and
 1968,  respectively.   Live  rodents were trapped in the treated and con-
 trol field from 1965  through 1969.  A total of 4,661 rodents were cap-
 tured, of which 162 were analyzed for residues.

     No parathion residues were  found in any of these specimens.   The
 species composition of the trapped rodents was similar  for the treated
 and the untreated study area,  as were the population levels of Peromyscus
 maniculatus. which comprised about 74% of the total rodent population
 in the two areas. Average minimal longevity for P^ maniculatus and
 monthly survival between June and September did not differ significantly
 between the treated and untreated area.   Thus,  none of  the parameters
 observed in this study indicated any effects on the wild rodent popula-
 tion from the use of  parathion at field rates over a 4-year period.

     Bejer-Petersen et al. (1972)I/ studied the effects of spray treat-
 ments  of parathion and other insecticides in forests on birds living
 in nest boxes.   Parathion  spraying (rate not given in abstract) was
 carried out in 1965 and in 1967  at a time when nestlings of Parus
 major  and P. ater were most numerous.   The loss rate of Parus nestlings
 was adversely affected by  the  parathion treatment.   The breeding  success
 of Ficedula hypoleuca.  the third species in these tests,  was  50%,  com-
 pared  to 64 to 100% in control areas.   Parathion residues in these birds
 ranged from traces to 11 ppm.  In several of the broods of each species,
 reduced brain cholinesterase activity was observed.   The sprayings had
 no effect on bird populations  in the years following the treatment.

                    7 /
     Bucknell (1970)i/  reported  deaths of a number  of species of  birds
 following the application  of parathion in granulated form.  The bird
 species  most frequently affected were  magpies,  gulls, hawks,  blackbirds,
 thrushes,  and finches.

     The summary on parathion  by Pimentel (1971)P_'  includes  the follow-
 ing three reports  on  wildlife  toxicity.
I/  Bejer-Petersen, B., R. R. Hermansen, and M. Weihe, "On the Effects
      of Insecticide Sprayings in Forests on Birds Living in Nest Boxes,"
      Dan. Ornithol. Foren. lidsskr.. 66(1,2):30-50 (1972).
2_/  Bucknell, E. S., "Side-Effects of Granulated Insecticides in
      Canterbury," Proc. N. Z. Weed Pest Contr. Conf. No. 23, pp. 124-126 (1970).
3/  Pimentel, D., "Ecological Effects of Pesticides on Nontarget Species,"
      Executive Office of the President, Office of Science and Technology,
      U.S. Government Printing Office, Washington, D.C.  (1971).
                                     162

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     Buttlker (1961)I/ reported on a large-scale spray program carried
out on a citrus estate In the Union of South Africa.  Parathion was
applied at 7.5 Ib Al/acre for the control of citrus insects.  In the
treated grove, nearly 800 birds were found dead.

     Mulla (1966)2/ reported that mallard ducks appeared to be un-
affected when duck ponds were treated with parathion at the rate of
0.85 Ib Al/acre.

     In a USDI (1966)-' study, parathion was applied at rates of 0.5
and 3.0 Ib Al/acre.  Pheasants were not affected by the lower rate,
but there was about 10% mortality at the 3.0-lb rate.

     Our search of the literature and of other information sources
failed to yield additional data on the toxicity of parathion to wild-
life under field conditions.  The data on the oral acute toxicity of
parathion to wildlife summarized by Tucker and Crabtree (1970)4' in-
dicate that parathion is highly toxic to all species studied.  This is
also evident from the data on the toxicity of parathion to wildlife
summarized by Pimentel (1971).

     Parathion labels carry the warning "Poisonous to fish and wild-
life.  This product is toxic to fish and wildlife.  Birds and other
wildlife in treated areas may be killed."

Effects on Beneficial Insects

Bees - Several investigators have reported on the toxicity of parathion
to bees (Apis mellifera) by direct topical application, or by exposing
bees to sugar solutions containing parathion, to parathion deposits on
inert surfaces, or to vapors from parathion residues.  By all of these
routes of application, parathion is highly toxic to bees.
I/  Buttiker, W., "Ecological Effects of Insect Control on Bird Popula-
      tions, "int. Union Conserva. Nature Natur. Resources, Tech. Meeting,
     ..Warsaw 1960, Proc . ,. 8:48-60 (1961).  Quoted from:  Pimenta Pimentel
2/  Mulla, M. S., "Vector Control Technology and Its Relationship to the
      Environment and Wildlife,"  J. Appl. Ecol.. 3( Supplement on
      Pesticides in the Environment and Their Effects on Wildlife): 2 1-28
      (1966).  Quoted from:  Pimentel (1971).
3_/  USDI, "Wildlife Research; Problems, Programs and Progress.  Pesticide-
      Wildlife Relations," Fish and Wildlife Serv., Bureau Sport Fish Wildlife
      Clrc. 43, 117 pp. (1966).  Quoted from:  Pimentel (1971).
4/  Tucker, R. K., and D. 6. Crabtree, "Handbook of Toxicity of Pesticide
      to Wildlife," U.S. Department of the Interior, Fish and Wildlife
      Service, Denver Wildlife Research Center, Resource Publication No.
      84, p. 82 (1970).
                                   163

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      The Handbook of Toxicology (WADC, 1959)!/ states:  "Parathion is
perhaps  the most generally potent insecticide presently in commerce."
This is  clearly supported by tabular listings of the effects of lethal
dosages  of parathion on a considerable number of insects.

     Stephen (1972)I/ recently studied the effects of chronic sublethal
doses of parathion on the behavior of the leafcutter bee (Megachile
rotundata). Bees emerging from diapause were treated topically with
sublethal doses of parathion (1 ug/g) at 2-or 3-hr intervals over a
24-hr period.  The authors concluded that the rhythmic responses to
parathion appeared to be light-cued, while the response to dieldrin,
another pesticide tested in the same manner, was temperature-dependent.
In a companion study on the effect of parathion on the ability of the
leafcutter bee to synchronize its activity rhythm to the environment,
there was no evidence of the clock being affected.  Web spinning be-
havior of the spider, Araneus diadamatus, was not affected by a single
application of parathion, but the amount of silk available was reduced.

     Barker (1970)—' investigated whether the classical antidotes
against parathion poisoning in mammals, atropine sulfate and N-methyl-
pyridinium-2-aldoxime (PAM), would work on honeybees.  When parathion
was applied to the thorax of bees, the 24-hr 1^5 Q was 0.08 to 0.16 ug/
bee.  Treated bees showed no reduction in mortality when atropine sul-
fate with or without salts of PAM was fed, applied topically, or in-
jected.  Thus, these parathion antidotes were ineffective on bees, at
least under the conditions of this experiment.

                       4 5/
     Johansen (1972a,b)—*—investigated the toxicity of field-weathered
residues of parathion and other insecticides to different species of bees,
I/  WADC, "Insecticides," The Handbook of Toxicology, Vol. Ill, Wright-
      Patterson Air Force Base, Ohio Air Force Systems Command, WDAC
      Tech. Report 55-16 (1959).
21  Stephen, W. P., "The Effects of Chronic Sublethal Doses of Pesti-
      cides on Behavior and Longevity in Arthropods,"  Oregon State
      Univ. Environ. Health Sci. Cent. Annu. Progr. Rep., pp. 161-167 (1972)
3/  Barker, R. J., "Cholinesterase Reactivators Tested as Antidotes for
      Use on Poisoned Honeybees," J. Econ. Entomol., 63(6) -.1831-1833
      (December 1970).
4_/  Johansen, C. A., "Spray Additives for Insecticidal Selectivity to
      Injurious vs Beneficial Insects," Environ. Entomol., l(l):51-54
      (February 1972a).
5/  Johansen, C. A., "Toxicity of Field-Weathered Insecticide Residues
      to Four Kinds of Bees," Environ. Entomol., l(3):393-394 (June 1972b).
                                   164

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Parathion from a 4-lb/gal emulsifiable liquid was applied to alfalfa
at the rate of 0.5 Ib Al/acre.  Three kinds of bees were exposed to
the parathion residues 10 hr after application.  Bee mortality was
determined after 24 hr and ranged from 41 to 667..  When bees were ex-
posed to 3-hr old residues of parathion on alfalfa treated at 0.5 Ib
Al/acre, mortalities ranged from 91 to 100%.  On 8-hr old residues,
mortalities ranged from 61 to 93%.

     The entomological literature contains many other records of the
toxic!ty of parathion to bees.  Within the limits of time and resources
available for this review, it was not possible, and was hot considered
of prime importance to collect and review the entire literature on the
toxicity of parathion to bees.  The high toxicity of this insecticide
to bees has been well established and is universally recognized.  Para-
thion labels state:   "This product  is highly toxic to bees exposed to
direct treatment or residues on crops."  Many extension service recom-
mendations concerning parathion carry specific warnings applicable to
local conditions, crops, etc.

Parasites and Predators - The importance of naturally occurring parasites
and predators of insect and mite pests in suppressing these pests and
reducing or preventing economic damage from their activities has been
increasingly recognized in recent years.  A number of investigators have
studied the effects of parathion on such parasites and predators, mostly
under laboratory conditions.

     Hamilton and Kieckhefer (1969)^' investigated the toxicity of para-
thion to predators of the English grain aphid (Macrosiphum avenae).
Adult and larval forms of the three most numerous and ubiquitous preda-
tors of cereal aphids in South Dakota, Hippodamia convergens (the con-
vergent lady beetle), Nabis americoferus. and Chrysopa carnea were
field-collected for  laboratory mortality tests.  By topical applica-
tion to adults, the LDgg °f parathion to the aphid was 1.8 ug/g, while
it was 21 ug/g to N^ americoferus  and 40 ug/g to H^ convergens.  LC5Q
values of parathion  to the same insects were determined by exposing the
insects to 4 and 24-hr-old deposits of  appropriate concentrations.  Again,
the LC5Q values of parathion to the predators were much higher than
to the aphid.
 I/ Hamilton, E. W., and R. W. Kieckhefer, "Toxicity of Malathion and
     Parathion to Predators of the English Grain Aphid," J. Econ.
     Entomol.. 62(5):1190-1192 (October 1969).
                                   165

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       Craft and Jeppson (1970)i/ studied the toxicity of parathion and
 other insecticides to Typhlodromus occidentalis,  an  important natural
 enemy of plant feeding mites in the Western United States.  Strains of
 this phytoseiid mite from Washington,  Utah, and California were studied
 at the University of California insectary.   All predator strains were
 uniformly tolerant to field use rates  of parathion.  The results' clearly
 indicate that strains of this predator from four  different locations
 have developed a high degree of tolerance to parathion.
                         . A /
     Moffitt et al.  (1972)-'  studied the  toxicity of parathion and several
 other frequently used orchard pesticides to the convergent  lady beetle
 (Hippodamia convergens), one of the more common and  important predators
 of aphids in deciduous fruit orchards  in Washington.  When  adult beetles
 were sprayed directly with parathion at 0.125 and 0.25  Ib AI/100 gaL
 or exposed to residues from parathion  sprays of these concentrations,
 none survived.  In orchard tests,  percent survival of H^ convergens
 adults exposed to residues  of parathion applied at 0.125 and 0.25  Ib
 AI/100 gal.was zero when the beetles were exposed for 2 days to 2-day-
 old residues.   When exposed'for 2  days to residues 9 days old,  83% of
 the beetles  survived in one test,  none in another.   Only 2% survived
 exposure to 12-day-old deposits for 5  days.

      The U>5o  of parathion  to adult beetles (topical application)  was
 0.062  ug/beetle.

     These data  indicate that parathion applications at the above  rates
 would  not be compatible  with  survival  of  adult beetles under field
 conditions.
                            •a /
     Lingappa  et  al.  (1972)—'  studied  the effects of parathion  on  three
 developmental  stages  of  Lysiphlebus testaceipes,  a parasite of  the
 greenbug (Schizaphis  graminum).  Field-collected  parasites were used
 to  experimentally parasitize  greenbugs.   One,  four,  and eight days after
 parasitization,  the greenbugs were transferred to sorghum plants about
I/  Croft, B. A., and L. R. Jeppson, "Comparative Studies  on Four
      Strains of Typhlodromus occidentalis.   II.  Laboratory Toxicity
      of Ten Compounds Common to Apple Pest Control,"  J.  Econ. Entomol.,
      63(5):1528-1531 (October 1970).
2/  Moftitt, H. R., E. W. Anthon, and L. 0. Smith, "Toxicity of Several
      Commonly Used Orchard Pesticides to Adult Hippodamia convergens,"
      Environ. Entomol.. 1(1):20-23 (February 1972).
3_/  Lingappa, S. S., K. J. Starks, and R. D.  Eikenbary, "Insecticidal
      Effect on Lysiphlebus testaceipes, a Parasite of the Greenbug,
      at Three Development Stages," Environ.  Entomol., 1(4):520-521
      (August 1972).

                                    166

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10 days old and sprayed in the laboratory with parathion at the equiva-
lent of 0.25 Ib Al/acre, the common greenbug control dosage.  Adult
parasites failed to emerge from the greenbugs that were exposed to
parathion 1 and 4 days after parasitism, while untreated controls had
94.1 and 93.9% emergence, respectively.  Parasite emergence from the
greenbugs exposed to parathion 8 days after parasitization was 76.5%
(97.8% in the untreated control).  The authors suggest that apparently
the host greenbugs were killed by the parathion treatment before the
parasite had completed larval development or, in the case of the 1-day-
old treatments, even before parasite eggs had hatched.  Thus, field
sprays of parathion at these early states in the life cycle of the
parasite would be distinctly detrimental to parasite survival.

     Several reports from overseas also deal with the effects of para-
thion on beneficial insects.  Gupta and Kushwaha (1970)—' found that
parathion and several other insecticides were toxic to the aphid preda-
tor  Menochilus sexmaculata.  Satpathy et al. (1968)—' studied the
toxicity of parathion and seven other insecticides to the aphid preda-
tor Chilomenes sexmaculata by feeding adult beetles with insecticide
poisoned aphids.  Parathion was among the insecticides most toxic to
the predator.  Teotia and Tiwari (1972)—' also found parathion to be
among the insecticides most toxic to the aphid predator  Coccinella
septembpunctata.

     The reports summarized in this section indicate that parathion
would permit survival of beneficial insects in some crop pest predator/
parasite systems, but certainly not in all.  The relative toxicity of
the insecticide to the pest and to the predators and parasites and
their respective life stages will have to be studied on a case-by-case
basis.  At least some predators and parasites appear to be capable of
developing tolerance or resistance to parathion in the same manner as
many insect and mite pests.
I/ Gupta, R. S., and K. 8. Kushwaha, "Toxicity of Some Insecticides to
     the Predator, Menochilus sexmaculata," Indian J. Entomol., 32(Pt.
     4):379-381 (1970).
2_/ Satpathy, J. M., G. K. Padhi, and D. N. Dutta, "Toxicity of Eight
     Insecticides to the Coccinellid Predator Chilomenes sexmaculata."
     Indian J. Entomol., 30(1):130-132 (1968).
3_/ Teotia, T. P. S., and G. C. Tiwari, "Toxicity of Some Important
     Insecticides to the Coccinellid Predator, Coccinella septempunctata,"
     Labdev. Part B, 10(1):17-18 (1972).
                                   167

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Interactions with Lower Terrestrial Organisms

Reviews - The relationships between insecticides and microorganisms
have recently been reviewed by several authors.  Matsumura and Boush
(1971)—' point out that organic phosphate pesticides (including para-
thion) have thus far apparently neither presented serious problems in
soils as regards undesirable persistence, nor demonstrated an extra-
ordinary affinity for fat with resulting concentration within a food
chain.  Although considerable variations exist between individual
organophosphates, most of them are readily degraded in soil, mainly
by hydrolytic and oxidative means.

     These authors also point out that, although several workers have
demonstrated in the laboratory that some microorganisms are able to
degrade even the most stable and persistent organic insecticides, no
one has yet demonstrated whether or not this occurs in nature, or
even that these compounds serve as nutritional or energy sources for
organisms.  "In fact there are no reports as yet that these chemicals
have been shown to serve as sole nutritional carbon sources."  The
incredible biological and chemical complexity of the soil is a formid-
able obstacle to gaining an understanding of the fate of pesticides in
that habitat, and of the mechanisms involved in their metabolism and
degradation in situ.

     Another recent review of the interactions between pesticides
(including parathion) and the soil fauna was authored by Drift (1970).—'

     Ecology, degradation and movement of pesticides in the soil were
reviewed in an international symposium at Michigan State University
in 1970.  The proceedings of this symposium have been published and
contain a wealth of general data and overviews of different aspects
of the subject, but no reports dealing specifically with parathion.
I/  Matsumura, F., and G. M. Boush, "Metabolism of Insecticides by
~"     Microorganisms,"  Soil Biochem., Vol.  II pp.  3.20-336, Marcel Decker,
      New York (1971).
21  Drift, j., "Pesticides and Soil Fauna," Meded. Rijksfac. Land-
      bouwwetensch..Gent, 35(2) : 707-716  (1970).
                                    168

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Field Studies - Bollen et al. (1954)i/ investigated the effects of
field treatments of insecticides, including parathion, on the numbers
of bacteria, Streptomyces, and molds in field plots in Oregon.  Para-
thion in the form of a wettable powder was incorporated with the soil
by rotary tillage at the rate of 10 Ib Al/acre.  Composite soil sam-
ples at plow depth were taken on the day of application and trans-
ported to the laboratory in paper bags or friction-top tin cans.
These containers were opened and allowed to stand, well isolated
from each other, until sufficiently dry for screening.  The samples
were then passed through a 10-mesh sieve and stored in friction-top
cans at room temperature for 10 to 20 days, when they were counted.
The counts of molds and bacteria in the parathion-treated samples
differed very little from those in the untreated controls.

     Hubbell et al. (1973)-^ studied the effects of several pesti-
cides, including parathion, on the relative numbers of microbes and
on nitrification in field plots to which the pesticides, alone and
in combination, had been applied at times and rates of application
approximating current agronomic practice in the growing of shadeleaf
tobacco in the area of Quincy, Florida.  Numbers of microbes and
nitrification were monitored at 2-week intervals for 16 weeks follow-
ing application.  There were no significant effects from the pesticide
treatments on the relative numbers of bacteria and actinomycetes.
The count of fungi increased in the parathion + DDT + Zineb treatment.
There were no significant effects on nitrification.

     Wolfe et al. (1973)2/  investigated the effects of very high
levels of parathion on soil microorganisms.  The extreme concentra-
tions of parathion in the soil studied by these authors resulted from
simulated spillage of concentrated parathion emulsifiable liquid and
dilute sprays.  Soil from a test plot that had received a topical
application of 45.5% emulsifiable concentrate of parathion 2 years
I/ Bollen, W. B., H. E. Morrison, and H. H. Crowell, "Effect of Field
     Treatments of Insecticides on Numbers of Bacteria,  Streptomyces,
     and Molds in the Soil," J. Econ. Entomol.. 47(2):302-306 (1954).
2/ Hubbell, D. H., D. F. Rothwell, W. B. Wheeler, W. B.  Tappan, and
     F. M. Rhoads, "Microbiological Effects and Persistence of Some
     Pesticide Combinations in Soil," J. Environ. Qual., 2(l):96-99
     (1973).
3/ Wolfe, H. R., D. C. Staiff, J. F. Armstrong, and S. W. Comer,
     "Persistence of Parathion in Soil," Bull. Environ.  Contain. Toxicol..
      10(1):1-9 (1973).
                                   169

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earlier  contained  3.47.  parathion, a concentration equivalent to 136,000
 Ib Al/6  acre-ft.    Soil from  this plot and soil  from a comparable, un-
treated  control plot were plated on nutrient yeast-dextrose agar con-
taining  different  levels of parathion, to determine if the soil organ-
isms might have developed resistance or tolerance to the insecticide.
The number of  colonies  that developed in 6 days  at 70°F was used as an
indicator.   Significantly fewer colonies of microorganisms were isolated
from the treated soil.   Microorganisms from the  treated soil showed no
evidence of  resistance  to parathion.

     These data indicate that soil organisms survive extremely high
concentrations of  parathion in the soil, even though they were adversely
affected.

Laboratory Studies - Several  authors have investigated interactions
between  parathion  and isolated microorganisms under laboratory condi-
tions.

     Mick and  Dahm (1970)!' incubated parathion  at concentrations in
the range of 10~^  to 10"^M with cultures of two  species of Rhizobium
and found that these fungi metabolized the insecticide primarily by
nitroreduction.    Eighty-five percent of the initial parathion was
reduced  to aminoparathion.  About 10% was hydrolyzed to the correspond-
ing phosphorothioic acid.  Both of these degradation products have
negligible toxicity compared  to parathion.  No paraoxon was detected.
Populations  of both Rhizobium species decreased  somewhat in the pres-
ence of  parathion  in the incubation mixtures.

     Mackiewicz et al.  (1969)—' investigated the biodegradation of
parathion in a germ-free system.  Bean roots grown under aseptic con-
ditions  were exposed to parathion for 7 days with or without the alga
Chlorella.   The only pesticide-related product found in extracts from
the aerial parts of plants exposed to the insecticide alone was parathion.
If Mick, D. L., and P. A. Dahm, "Metabolism of Parathion by Two Species
"    of Rhizobium," J. Econ. Entomol.. 63(4):1155-1159 (August 1970).
21 Mackiewicz, M., K. H. Deubert, H. B. Gunner, and B. M. Zuckerman,
     "Study of Parathion Biodegradation Using Gnotobiotic Techniques,"
     J. Agr. Food Chem.. 17(1):129-130 (January/February 1969).
                                   170

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 By contrast, parathlon and a sulfur-containing parathion metabolite
 were recovered from bean leaves and stems of plants whose  roots  were
 exposed to both parathion and the algae.  The authors conclude that
 parathion metabolites found in plants may be a product  of  microbial
 metabolism, rather than metabolism by the plant as has  generally been
 assumed by other authors.  They emphasize the utility of,  and often
 the requirement for, germ-free systems in the study of  the degradative
 pathways of pesticides.

      Cowley and Lichtenstein (1970)17  studied  the  toxic  effects of
parathion and other insecticides  on 17  species  of fungi from Wisconsin
prairie soils.   The fungi,  including Aspergillus fumigatus and Fusarium
oxysorum, were grown on nutrient  agar that had  been treated  with the
insecticides at six rates,  ranging from 1  to  40 ug/ml.  The  pesticide-
containing inoculated culture media were incubated  for 5  days at about
34°C.   The dry weight of each colony was then determined  as  a measure
for the toxicity of the insecticides.   In  further,  similar tests,  yeast
extract, vitamins,  and nitrogenous compounds  were added to the cultures
to study possible counteractions  of insecticidal effects.  Relative
sporulation was evaluated by visual inspections, and the  diameter  of
each fungal colony was also recorded.

      Parathion and all other insecticides inhibited the growth of most
 of the fungal species.  Threshold concentrations at which no decrease
 in fungal growth occurred differed for each compound,  and also for each
 of the two fungal species.  None of the fungi tested were able to use
 parathion or any of the other insecticides as a source of carbon or
 phosphorus.
                     2 /
      Anderson (1971)—' investigated the capacity of several fungi iso-
 lated from an agricultural loam soil to degrade DDT or dieldrin.   He
 reported that Mucor alternans in shake cultures partially degraded DDT
 within 2 to 4 days into two water-soluble metabolites.   At a concen-
 tration of 1 ppm, parathion partially inhibited DDT degradation by this
 fungus, although fungal growth was not drastically affected. A para-
 thion hydrolysis product,  p-nitrophenol,  had no effect on fungal  growth
 or DDT degradation.
 I/ Cowley, G. T., and E. P. Lichtenstein, "Growth Inhibition of Soil
      Fungi by Insecticides and Annulment of Inhibition by Yeast Extract
      or Nitrogenous Nutrients," J. Gen. Microbiol.. 62(l):27-34 (1970).
 2/ Anderson, J. P. E., "Factors Influencing Insecticide Degradation
      by a Soil Fungus, Mucor Alternans," Piss. Abstr. Int.. 32(6):3114B-
      3115B (1971).
                                   171

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     Sethunathan and Yoshida  (1972, 1973)!*^/ found that parathlon
and several other organic phosphate insecticides were rapidly hydro-
lyzedby a cell-free extract of a species of Flavobacterium isolated
from water of a rice field that had previously been treated with
diazinon.  Most of the parathion was rapidly decomposed.(within 30
min), without a lag phase.  The major metabolite formed was p-nitro-
phenol which was not further  degraded by the organism.  No appreciable
degradation of aminoparathion was observed.

     Griffiths and Walker (1970)^ investigated the microbiological
degradation of parathion in soil percolation experiments.  Parathion
in the soil was degraded by a heat labile agent which was transferable
in small amounts between soil cultures.  This observation is consistent
with the effects of microorganisms, but the responsible organisms have
not been isolated in pure cultures.

Residues in Soil

                                        4/
Laboratory Studies - Iwata et al. (1973)—  investigated the persistence
of parathion in six California soils under laboratory conditions.
Each soil was fortified with  20 ppm (equivalent to 80 Ib AI/6 acre-foot)
of parathion, kept in enameled trays, and maintained at 30°C and a soil
moisture level of approximately 40% of saturation.  In four of the six
soils (Mocho silt loam, Linne clay, Madera sandy loam, and Laveen loamy
sand), residues decreased rapidly, i.e., from 20 ppm to 0.2-2.0 ppm in
30 days.  Chemical hydrolysis and microbial degradation were responsible
for the rapid decline.  In Windy loam, the residue remained above 3,0
ppm after 8 months.  In two experiments differing slightly in soil
I/ Sethunathan, N., and T. Yoshida, "Conversion of Parathion to Para-
     nit rophenol by Diazinon Degrading Bacterium," Proc. Inst. Environ.
     Scl. Annu. Tech. Meet. 18:255-257 (1972).
2j Sethunathan, N., "Degradation of Parathion in Flooded Acid Soils,"
     J. Agr. Food Chem.. 21(4)-.602-604 (1973).
3/ Griffiths, D. C., and N. Walker, "Microbiological Degradation of
~"    Parathion," Meded. Rijksfac. Landbouvwetensch., Gent, 35(2):805-810
     (1970).
4/ Iwata, Y., W. E. Westlake,  and F. A. Gunther, "Persistence of Para-
     thion in Six California Soils Under Laboratory Conditions," Arch.
     Environ. Contain. Toxicol., 1(1):84-96 (1973).
                                   172

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moisture, the residue in Santa Lucia silt loam was about 1.5 ppm after
8 months in one experiment, and about 0.5 ppm after 6 months in the
other.  The latter two soil types gave linear semilogarithmic per-
sistence curves, suggestive of degradation by hydrolysis.  The degrada-
tion of the parathion residues remaining in Windy loam (3.2 ppm) and
Santa Lucia silt loam (2.2 ppm) 7.7 months after fortification was not
greatly accelerated by flooding with water.  Parathion disappeared
more rapidly in soils with low organic matter, suggesting that binding
to organic matter may reduce the availability of parathion for degradation.

     According to the authors, the results of this study support the
conclusion of other investigators that most of the parathion applied
to soil disappears rapidly, but that low levels may be retained by the
soil for extremely long periods.  The persistence of parathion is par-
tially dependent on soil types.  In soils with strong microbial activity,
rapid biological degradation tends to overshadow differences in soil
types.  In situations where hydrolysis is the primary degradative mech-
anism, differences in soil type exert greater influence.

     Campbell et al. (1971)—' studied the influence of organic matter
content of soils on the efficacy of parathion against the wireworm
(Melanotus communls)in the laboratory.  Parathion and most of the other
insecticides tested were affected by the organic matter content of the
soil; wireworm control increased with decreasing organic matter content.
These observations support the results of other studies, including those
by Iwata et al. (1973) discussed above, that soil organic matter binds
parathion residues, reducing their availability for insect control as
well as degradation.

                           7 /
     Weidhaas et al. (1961)—' reported on the adsorption of parathion
by soil from water dispersions and vermiculite granules.  Different
volumes of water (100 or 250 ml) containing 0.02 ppm of parathion were
added to jars containing 50 g of soil that had been premoistened with
25 ml of untreated water.  Changes in the insecticide content of the
supernatant water and of the soil were monitored by analyzing extracts,
0, 6, and 24 hr after preparation.  Immediately after initiation of the
 If  Campbell, W. V., D. A. Mount, and B. S. Heming, "Influence of
      Organic Matter Content of Soils on Insecticidal Control of the
      Wireworm," J. Econ. Entomol., 64(l):41-44 (1971).
 2_/  Weidhaas, D. £., M. C. Bowman, and C. H. Schmidt, "Loss of Para-
      thion and DDT to Soil from Aqueous Dispersions and Vermiculite
      Granules," J. Econ. Entomol., 54(1):175-177 (1961).
                                    173

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 test, most  of the  parathlon was  found in the water, but  the  amount in
 the  soil  increased as  time elapsed,  indicating  soil adsorption.  When
 parathion was applied  in formulations on vermiculite  granules  contain-
 ing  0.01  and 0.0257. of AI (weight/weight),  it  was readily released
 into water  from the granules.  The radiometric  results were  supplemented
 by bioassay tests  of extracts  of water and soil with  mosquito  larvae.
 The  results show that  parathion  dispersed in water looses insecticidal
 toxicity  in the presence of soil,  and that this loss  results primarily
 from adsorption on the soil.

     Harris (1966)17 investigated the bioactivity of  parathion and
 other insecticides in  10 soil  types,  employing  a bioassay technique
 using first instar nymphs of the common field cricket (Acheta
 pennsylvanicus)  as the test insect.   Soils  were tested  both dry and
 moist.  In  most soils,  bioactivity was dependent on the  organic con-
 tent of the soil.   Parathion was 1,132 times less active in  a  muck
 soil containing 64.6%  organic  matter  as compared to quartz sand.  There
 was  no direct correlation between organic content and bioactivity in
 dry  soils.   The presence of moisture  activated  parathion in  mineral
 soils, but  not in  muck soils.  The author concluded that in  muck soils,
 parathion (and other insecticides) appear to be sorbed in such a fashion
 that they are not  released from  active sites on soil  particles in the
 presence  of moisture.   Between different pesticides (chlorinated hydro-
 carbon and  organophosphate insecticides)  and different soil  fractions
 (clay, sand,  silt,  and organic),  at least three different bonding
mechanisms  appear  to exist.

     Burkhardt and Fairchild (1967a)-'  also  employed  a cricket species,
Acheta domesticus,  as  bioassay test insects  in  laboratory studies de-
 signed to determine the bioactivity of parathion and  other insecticides
 in five soil types,  each at two moisture levels.  The insecticidal
 activity of parathion  (and of  the  other insecticides  tested) varied
with soil type and moisture content.   Highest initial insect mortality
was  obtained in  the sandy soils, but  the residual activity was shorter
in these.   Increased moisture  generally resulted in increased  insect
mortality.
I/ Harris, C. R., "Influence of Soil Type on the Insecticidal Activity
     of Insecticides in Soil," J. Econ. Entomol.. 59(5):1221-1225
     (1966).
2/ Burkhardt, C. C., and M. L. Fairchild, "Toxicity of Insecticides to
     House Crickets and Bioassay of Treated Soils in the Laboratory,"
     J. Econ. Entomol.. 60(6):1496-1503 (1967a).
                                    174

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     Llchtenstein et al. (1966)17 studied the effects of detergents on the
persistence of parathion in the soil.  The addition of alkyl benzene
sulfonate detergents to insecticide-treated soils increased the per-
sistence of parathion.  Parathion was applied to Carrington silt loam
free of insecticidal residues at the rate of 10 ppm.  The treated
soils, with and without detergents added, were incubated for 15 days
at 30°C.  At that time, 28.57. of the amount of parathion applied was
recovered from the soil without added detergents, while 79.5 and 80.07,,
respectively, of the applied rate were recovered from soils to which
two different detergents had been added.  Soils not treated with the
detergents had an average count of 4.33 million bacteria per gram of
dry soil, while those treated with the detergents contained 56.7 and
228 million, respectively, 15 days after incubation.

     In a further experiment, parathion was applied to a loam soil
and a quartz sand at the rate of 10 ppm with or without detergents.
Two months after the insecticidal and detergent applications, 13 times
more parathion was recovered from the loam soil that had been treated
with detergent, as compared to the series free of detergents.  In the
quartz sand, only 0.5 to 3 times more parathion was recovered from the
detergent-containing as compared to the detergent-free systems.

     The effects of detergents and inorganic salts in water on the
persistence and movement of parathion in soils were investigated by
Lichtenstein et al. (1967).£/  Quartz sand of low sorptive capacity
and minimal microbiological activity served as control.  The effects
of the sorptive capacities of a loam soil became evident.  Water that
had been treated at the rate of 2 Ib of parathion per 6-in. acre con-
tained only small amounts of parathion after it had been percolated
through untreated loam soil.  The amount of parathion found in the
percolated water was a function of the concentration of the insecticide
in the soil.  When detergents (alkyl benzene sulfonates) were added to
the system, they increased the persistence of parathion in the soil
and the amount of parathion in the percolated water.  When untreated
water, with or without added detergents, was percolated through soil
treated with parathion at the rate of 20 Ib Al/acre, parathion concen-
trations in the percolated water samples ranged from 0.2 to 0.8 ppb.
I/ Lichtenstein, E. P., K. R. Schulz, R. F. Skrentny, and Y. Tsukano,
     "Toxicity and Fate of Insecticide Residues in Water," Arch. Environ.
     Health, 12:199-212 (1966).
2_/ Lichtenstein, E. P., T. W. Fuhremann, K. R. Schulz, and R. F.
     Skrentny, "Effect of Detergents and Inorganic Salts in Water on
     the Persistence and Movement of Insecticides in Soils," J. Econ.
     Entomol.. 60(6):1714-1721 (1967).
                                  175

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These  amounts  are  far below  the water  solubility of parathion, and the
water  was  not  toxic  to mosquito larvae.  When  salts were added to the
percolating water, it reduced  the  amount of parathion residues found in
it.

     From  these  results,  the authors conclude  that it appears unlikely
that water in  deeper soil strata could become  contaminated with insec-
ticidal residues from the upper agricultural soil layers.

     The behavior  of parathion when applied to the surface of soils was
studied in flow-through lysimeters by  Herzel (1971).U ' The lysimeters,
1.35 m long, were  packed  with  sand or  sandy loam, with or without a 20-cm
covering of humus, treated with parathion and  the other insecticides at
recommended rates, and watered with the equivalent of normal or excessive
rainfall.  Samples of the runoff and percolated water collected through-
out the test,  and  soil cores taken at  the end  of the 8-month test were
analyzed by gas  chromatography.  Parathion (as well as the other insec-
ticides studied) moved downward more easily in the sand than in the loam,
and was strongly retained in the humus covering.  No parathion was found
in any of  the  soil or water  samples after 8 months.

     In a  follow-on  test,  10 ml of concentrated parathion was applied
to the center  of the lysimeter surfaces.  For  an additional period of
15 months, one-half  of the lysimeters  were again watered with the equiva-
lent of normal rainfall,  the other half at the excessive rate, equiva-
lent 0.4 in. of  precipitation  each day.  After 15 months in this second
test,  very little  parathion  was found  at the 50- to 100-cm soil levels.

     Sethunathan (1973) studied the persistence of parathion in India
in five acid soils under  flooded conditions.   The product degraded
faster in  soils which had  a  high organic matter content.  The fastest
degradation occurred in an acid sulfate soil with an organic content
of 12.2%.  The author attributes this  to microbial participation.
Hydrolysis of parathion to j^-nitrophenol was enhanced by repeated
additions of parathion to  an alluvial  soil.  Heat treatment of this
system retarded the rate of hydrolisis  of parathion,  indicating the
role of biological agents  in the process.  A Bacillus species capable
of readily decomposing jo-nitrophenol was isolated from the parathion
enriched flooded alluvial  soil.
if Herzel, F., "The Behavior of Several Persistent Insecticides in the
     Soil," Bundesgesundheitsblatt   14(3):23-28 (1971).
                                  176

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     Sethunathan and Yoshida (1973)1.' studied the persistence and
degradation of parathion in Philippine rice soils in the laboratory,
simulating submerged and upland conditions.  Parathion was incubated
in the different soils at 30°C, then extracted with a hexane-acetone
mixture and determined by gas chromatography.  Parathion disappeared
more rapidly from submerged soils than from upland soils.  In sub-
merged soils, it was reduced to aminoparathion.  Autoclaving of the
soils increased the persistence of parathion under submerged condi-
tions, indicating microbial involvement in the degradation.  Inocula-
tion of flooded soils with Flavobacterium species accelerated the  rate of
degradation of parathion as compared to uninoculated soil.  This bac-
terium, isolated from paddy water, had been shown to be highly efficient
in hydrolyzing parathion in previous tests.

                              2/
     Chopra and Khullar (1971)—  found that the  following experimental
conditions accelerated the rate of degradation of parathion in soils
in laboratory tests:  increased concentration of parathion; increased
temperatures; increased time of exposure to UV light; increased rela-
tive humidity; and increased pH.  Hydrolysis was more rapid in alkaline
and acidic soils than in neutral ones.  The authors point out that some
of the loss occurring with increasing temperature may have been due to
vaporization.

     Swoboda and Thomas (1968)—' investigated the movement of para-
thion in eight important agricultural soils from various locations in
Texas in laboratory studies.  ^^P-labeled parathion was applied at an
initial concentration of 16.5 ppm (equivalent to 66 Ib Al/acre-foot)
to laboratory columns prepared from the soils, and leached through the
columns with distilled water.  Distribution coefficients for the adsorp-
tion of parathion were calculated, and the amount of rainfall required
to leach parathion to a depth of 60 in. was estimated.  This amount
varied from 230 in. for a Nacogdoches clay subsoil to 1,725 in. for a
Houston Black clay surface soil.  Desorption experiments indicate that
parathion is not effectively displaced by inorganic electrolyte salts,
or by aqueous solutions.  However, it moved swiftly through the soil
JL/  Sethunathan,N., and T. Yoshida, "Parathion Degradation in Submerged
      Rice Soils in the Philippines,"  J. Agr. Food Chem.. 21(3):504-
      506 (1973).
2_/  Chopra, S. L., and F. C. Khullar, "Degradation of Parathion in Soils,"
      J. Indian So. Soil Sci., 19(1):79-85 (1971).
3_/  Swoboda, A. R., and G. W. Thomas, "Movement of Parathion in Soil
      Columns," J. Agr. Food Chem.. 16(6):923-927 (November/December
      1968).
                                   177

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columns when leached with ethanol.  From the data obtained, the authors
conclude that it is very unlikely that parathion could contaminate
underground water supplies beneath any of these soils by leaching under
normal rainfall conditions.

     Leenheer and Ahlrichs (1971)!/ performed kinetic and equilibrium
studies on the adsorption of parathion on soil organic matter surfaces,
using two types of Indiana soil, i.e., a silty clay loam and a muck
soil.  They found that the differences in adsorptive characteristics
of various types of soil organic matter were small, but changing the
saturating cation from calcium to hydrogen greatly increased the adsorp-
tive capacity for parathion.  The authors conclude that the fast adsorp-
tion rates, the low heats of adsorption, the reversibility of adsorption,
and the high adsorptive capacities on hydrophobic surfaces tend to rule
out chemisorption, pointing instead to physical adsorption with forma-
tion of Van der Waals bonds between the hydrophobic portions of the
pesticide molecules and the adsorbent surfaces in aqueous systems.

     Saltzman et al.(1972),-' Saltzman and Yaron (1972)2/, and Yaron
and Saltzman (1972)*'  used parathion labeled with 14C  in the alkyl
chain in studies on the influence of soil organic matter on the adsorp-
tion of parathion.  In aqueous solutions, parathion had greater affin-
ity for organic than for mineral colloid adsorptive surfaces.  Parathion
bonding was stronger on organic than on mineral surfaces.  When aqueous
and hexane solutions containing from 1 to 10 ug of parathion per milli-
liter were applied to three soil types under different conditions, there
was no appreciable thermic effect on the adsorption of parathion from
aqueous solutions after correction for increased solubility.  Increasing
soil water content resulted in decreasing parathion adsorption.
\l  Leenheer, J. A., and J. L. Ahlrichs, "A Kinetic and Equilibrium
      Study of the Adsorption of Carbaryl and Parathion Upon Soil Organic
      Matter Surfaces," Soil Sci. Am. Proc.. 35(5):700-705 (1971).
2_/  Saltzman, S., L. Kliger, and B. Yaron, "Adsorption-Desorption of
      Parathion as Affected by Soil Organic Matter," J. Agr. Food Chem.,
      20(6):1224-1226 (1972).
3/  Saltzman, S., B. Yaron, "Parathion Adsorption from Aqueous Solutions
      as Influenced by Soil Components." In:  Fate of Pesticides in
      Environment, Gordon and Breach, London, pp. 87-100 (1972).
4_/  Yaron, B., and S. Saltzman, "Influence of Water and Temperature on
      Adsorption of Parathion by Soils," Soil Sci. Soc. Am. Proc.,
      36(4):583-586 (1972).
                                  178

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     In another test series, adsorption isotherms were obtained for
20 soils, Na-kaolinite, Na-montmorillonite, organic material, and
glass beads.  The results showed that the main soil components affect-
ing parathion adsorption are the expanding-lattice clays and the
organic matter which present linear adsorption isotherms.  Parathion
adsorption on nonexpanding-lattice clays and on noncolloidal soil
materials is reduced.

     King and McCarty (1968)i/ developed a chromatographic model for
predicting pesticide migration in soils.  For several insecticides,
including parathion, theoretical elution curves based on chromato-
graphic theory were developed and compared with experimental degrada-
tion and leaching data.  Four soil types, and different column lengths
and pesticide application rates were employed.  Analysis of the experi-
mental data and their correlation with the theoretically derived curves
establish the feasibility of predicting the extent to which organic
phosphate insecticides may be leached through soil columns.  The equa-
tion describing the chromatographic movement of the pesticides takes
into account the noncontinuous flow conditions which would be expected
in typical agricultural practice.  Critical variables include the
degradation rate of the pesticide, the distribution of the pesticide
in the soil water environment, and the decay reaction rate constant
under the environmental conditions prevailing.  Problems may arise
when the water solubility of the pesticide is approached, if the
degradation of the pesticide increases due to biological acclimation,
and from similar factors.

Field and Combined Field-Laboratory Studies -

     Short-term studies - Several authors have studied the persistence
of parathion under field conditions.

     Lichtenstein and Schulz (1964)—' applied parathion at 5 Ib Al/acre
to Carrington silt loam field plots.  Residue levels of parathion of
approximately 0.1 ppm (3.1% of the applied dosage) were reached under
field conditions within 90 days after the insecticidal application to
the soil.
I/  King, P., and P. L. McCarty, "A Chromatographic Model for Predicting
      Pesticide Migration in Soils," Soil Sci.. 106(4):248-261 (1968).
2/  Lichtenstein, E. P., and K. R. Schulz, "The Effects of Moisture
      and Microorganisms on the Persistence and Metabolism of Some
      Organophosphorus Insecticides in Soils, with Special Emphasis
      on Parathion," J. Econ. Entomol.. 57:618-627  (1964).
                                   179

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     Under laboratory conditions  (30°C), 30% of the applied parathion
dose was lost within 12 days after application to a loam soil.  In
further laboratory studies, the effects of moisture and microorganisms
on the persistence and metabolism of parathion in Carrington silt loam
soil were tested at 30°C.  Parathion was most persistent in dry soil,
least persistent in soils with high moisture content.  There was no
loss of parathion through volatilization.  Parathion was degraded either
by hydrolysis or by reduction to  its amino form, depending on popula-
tions of soil microorganisms.  In autoclaved soils that had low numbers
of microorganisms, or in dry soils in which microorganism activity was
low, parathion residues persisted for a relatively long time.  No amino-
parathion was formed in autoclaved soils.  Paraoxon, a parathion metab-
olite, was hydrolyzed within 12 hr after its application to loam soil
at 20 ppm.  During that time, the amount of paraoxon decreased con-
stantly, while the amount of j>-nitrophenol increased.  Aminoparathion
or £-nitrophenol, added to soils, disappeared within 2 and 16 days,
respectively.

     Burkhardt and Fairchild (1967b)i' applied parathion (from a
granular formulation) at 1, 2 and 4 Ib Al/acre in a 7-in. band at
planting time in field studies located in four counties in Missouri.
Soil samples were taken at various depths both in the treated row and
adjacent to the row, and bioassayed with 21-day old house crickets,
Acheta domesticus. to determine bioactivity and vertical and lateral
movement of the insecticide.  Based on the bioassay results from all
field plots combined, parathion at 1 Ib Al/acre provided 78% mortality
after 1 day; 77% after 1 week; 86% after 2 weeks; 47% after 4 weeks;
37« after 6 weeks; 0% after 8 weeks.  At the 4-lb Al/acre rate, para-
thion provided 1007. mortality during the first 2 weeks after applica-
tion; 98% after 4 weeks; 33% after 6 weeks; 25% after 8 weeks.  Results
from the 2-lb Al/acre rate were intermediate.  At all three applica-
tion rates, there was a sharp drop in bioactivity after the 4th week.
There was little downward movement of parathion; in the majority of
soil samples from the parathion-treated plots, very little or no bio-
activity was found more than 3 in. below the soil surface.  Horizontal
movement of parathion likewise was minimal.
I/ Burkhardt, C. C., and M. L. Fairchild, "Bioassay of Field-Treated
     Soils to Determine Bioactivity and Movement of Insecticides,"
     J. Econ. Entomol.. 60(6):L1602-1610 (1967b).
                                   180

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     Sacher et al. (1972)1' studied the bioactivity and persistence of
several parathion formulations in the soil under laboratory and field
conditions.  They found that moisture and soil type influenced the
rate of degradation of parathion, but this influence was mediated pri-
marily by the activity of microorganisms.  Highest biological activity
against larvae of the Western corn rootworm, Diabrotica virgifera, in
soil was obtained with a low-concentrate formulation with minimum bind-
ing of parathion (1% kaolinite dust, insect 1*050 0.05 ppm), whereas
low activity resulted from a tightly bound, concentrated, thinly dis-
tributed formulation (10% on charcoal, LD^g 6.0 ppm).  However, para-
thion applied by way of the kaolinite dust formulation had a half-life
in soil of only 6 days, compared to more than 72 days for the 107. char-
coal granules.

     Microbial degradation appeared to be a major contributor to para-
thion breakdown in soil.  Ray silt loam was treated with parathion 10%
granules on vermiculite at 20 ppm.  Only about 30% of the applied rate
was still present, as determined by chemical assay, 6 weeks after
treatment.  When the same soil was sterilized by treatment with methyl
bromide (1 g/100 g of soil) prior to the parathion application, there
was no appreciable parathion decline after 6 weeks.

     The importance of microbial activity in the soil degradation of
parathion was further demonstrated in field tests in which it was
shown that the rate of parathion degradation was much slower in field
soils in the winter months when soil microorganisms are dormant.  Most
rapid breakdown occurred in August and September when the half-life of
parathion in the soil was as short as 1.5 weeks.

                         2/
     Knutson et al (1971)—' studied the relationships between insecticide
usage and resulting residues in a newly developed irrigation district
in central Kansas.  This area had previously been under dry land farm-
ing practices with little exposure to insecticides.  Parathion was
applied to irrigated corn at planting time at treatment rates ranging
from 0.79 to 1.40 Ib Al/acre each year during a 4-year period, 1966
to 1969.  Soil samples taken immediately after each annual application
I/  Sacher, R. M., G. F. Ludvik, and J. M. Deming, "Bioactivity and
      Persistence of Some Parathion Formulations in Soil," J. Econ.
      Entomol., 65(2):329-332 (April 1972).
21  Knutson, H., A. M. Kadoum, T. L. Hopkins, 6. F. Swoyer, and T. L.
      Harvey, "Insecticide Usage and Residues in a Newly Developed
      Great Plains Irrigation District," Pest. Monit. J.» 5:17-27 (1971)
                                  181

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had average parathion residues ranging from 0.5 ppm to 4.07 ppm.  No
detectable parathion residues were found in samples obtained 1.5 and
2.5 months after treatment.  No residues vere detected in corn; grain,
in capped wells from 13 to 71 ft deep, nor in surface water samples
from the Smoky Hill River and the Cedar Bluff Reservoir, the water
bodies draining the area.

     Harris and Sans (1971)—' studied insecticide residues in soils on
16 farms in southwestern Ontario in 1964, 1966, and 1969.  Residues of
organophosphate insecticides were determined qualitatively by a non-
specific enzymatic analysis, and quantitatively by 6LC where possible.
The use pattern of insecticides in the area showed that organophosphate
insecticides were used at an increasing rate from 1965 to 1969.  Pre-
liminary findings indicated that the more extensive use of the organo-
phosphate insecticides resulted in residues of these products in
vegetable soils, while the enzyme inhibition tests in 1969 indicated
that inhibitory substances were generally below significant levels in
field crop, tobacco, and orchard soils.  Parathion and paraoxon residues
were positively identified by GLC analysis on at least one of the 16
farms studied.

                      2/
     Mol et al. (1972)=-' investigated the persistence of parathion
residues in the field after winter applications of parathion at 3.0
and 6.0 Ib/acre  in Australia.  Parathion residues in top soil de-
creased from 6.5 ppm initially to 4.7 ppm 3 months after application
of the lower rate, and from 10.7 ppm to 8.5 ppm at the higher rate.
No detectable residues were found in the soil at either application
rate after 8 months.  Little soil penetration of parathion was found
below a depth of 1 in.

     Kilgore et al. (1972)!/ analyzed soil samples from a vineyard
sprayed with parathion emulsifiable concentrate at 4 and 8 Ib. Al/acre
for parathion residues.  Following the 4 Ib/acre application, parathion
I/ Harris, C. R., and W. W. Sans, "Insecticide Residues in Soils on 16
"    Farms in Southwestern Ontario  -  1964, 1966, 1969,"  Pest. Monit. J..
     5(3):259-267 (December 1971).
2j Mol, J. C. M., D. L. Harrison, and R. H. Talfer, "Parathion:  Toxicity
     to Sheep and Persistence on Pasture and in Soil," N.Z. J. Agr. Res..
     15(2):306-320  (1972).
3/ Kilgore, W. W., N. Marey, W. Winterlin, "Parathion in Plant Tissues:
     New Considerations."  In:  Degradation of Synthetic Organic Molecules
     in the Biosphere, National Academy of Sciences, pp. 291-312 (1972).
                                  182

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concentration in the soil was 21 ppm at 0 days, 0.06 ppm at 46 days
after treatment.  Following the 8-lb/acre treatment, parathion con-
centration in the soil was 70 ppm at 0 days, 0.13 ppm at 46 days after
treatment.

     Long-term field studies - Stewart et al. (1971)!/ and Chisholm and
MacPhee (1972)2/ investigated the long-term persistence and effects of
parathion (and several other pesticides) in the soil in a field experi-
ment at Kentville, Nova Scotia.  Parathion was applied to a sandy loam
at the rate of 31.4 Ib Al/acre (equivalent to 15.7 ppm in the upper
6 in. of soil) from a 15% wettable powder formulation.  This rate was
intended to approximate the maximum concentration in the soil (neglect-
ing loss through volatilization, etc.) that might accrue from an inten-
sive spray program carried on over a 20- to 25-year period, and it was
applied each spring from 1949 to 1953 inclusive.  Each time, the in-
secticide was thoroughly incorporated to a depth of 6 in. with a rotary
cultivator, and various crops were grown on the plots each year up to
1969.  In the spring of 1969, 16 years after the last application, soil
samples were taken at various depths from the experimental plots and
analyzed for parathion residues.  The 0.06 ppm of parathion was found
in the 0-to 4-in. soil layer; 0.063 ppm in the 4-to 8-in. layer, 0.008
ppm in the 8-to 12-in. layer, and a trace amount at the 12-to 16-in.
depth.  Thus, about 0.1% of the total parathion applied to the plot
(157 Ib Al/acre) was still present 16 years after the last application.

     Voerman and Besemer (1970)27 reported on an experiment started in
1953 at Wageningen, The Netherlands, and continued for 15 years, up to
1968.  Parathion (and other insecticides) were sprayed in two concen-
trations on crops several times each year.  In addition, soil treat-
ments of these insecticides were applied once a year.  Soil and crop
samples were takenvand analyzed throughout the entire period.  The
experiment was conducted in light, sandy soil.  From 1963 to 1968,  the
total quantities of parathion applied to three different plots were
10.4, 21.5 and 111.4 Ib Al/acre.  Soil residues found in the 0-to 4-in.
I/ Stewart, D. K. R., D. Chisholm, and M. T. H. Ragab, "Long-Term
     Persistence of Parathion in Soil," Nature, 229:47 (1971).
2f Chisholm, D., and A. W. MacPhee, "Persistence and Effects of Some
     Some Pesticides in Soil," J. Econ. Entomol., 65(4):
     1010-1013 (August 1972).
3_/ Voerman, S., and A. F. H. Besemer, "Residues of Dieldrin, Lindane,
     DDT, and Parathion in a light Sandy Soil After Repeated Applica-
     tion Throughout a Period of 15 Years," J. Agr. Food Chem., 18(4):
     717-719 (1970).
                                   183

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soil layer after  15 years of repeated applications were 0.01, 0.02 and
0.06 ppm, respectively, equivalent to 0.17. of the applied amount  for
each application  rate.  No parathion residues.were detected in the
4-to 8-in. soil layer in the plots that had received the two  lower
rates, while 0.02 ppm  was found in that layer following the  heaviest
parathion applications.  No parathion residues were found in  deeper
soil layers.

     Massive soil contamination with parathion may result from the
spillage of pesticides, especially from repeated spillage in  areas
where spray tanks are routinely loaded.  Wolfe -.and Durham (1966)I/
set up a replicated field test to simulate spillage of undiluted  para-
thion emulsifiable concentrate containing 45.6% Al/gal.  In another
test, soil contamination from tank drainage on the ground with dilute
(Ix) and concentrate (8x) liquid sprays, using both wettable  powder
and emulsifiable  concentrate formulations, was simulated.  The test
plots were in orchard silt-loam soil with high organic material con-
tent, and a pH ranging from 4.4 to 5.5.  The plots were exposed to
weathering and regular sprinkler irrigation.

     The top 1 in. of soil contaminated with the emulsifiable concen-
trate contained 59,000 ppm of parathion Initially.  Forty-six percent
of this residue was still present after 2 years.  The soil contaminated
with the dilute formulations had initial surface-soil concentrations
of parathion of 98 to 108 ppm from the Ix spray, and from 370 to  1,126
ppm from the 8x spray.

      The authors  then collected and analyzed  top soil samples from 37
spray tank fill sites  throughout the Wenatchee Valley, Washington  area.
The time intervals between contamination of soil and sampling  for  analysis
were not known.  Parathion residues  found ranged from 0.3 to 330 ppm, with
a mean of 48.4 ppm.  The authors conclude that parathion residues  may
persist in the soil at relatively  high  levels  for long periods of  time.


     The experimentally contaminated field plots described by Wolfe and
Durham (1966) were monitored further,  and more recent findings were re-
ported by Wolfe et al. (1973).  Farathion residues persisted  at rela-
tively high levels for 5 years following the initial applications.
I/ Wolfe, H. R., and W. F. Durham, "Spillage of Pesticides and Residues
~~    In Soil," Wash. State Hort. Assoc. Proc., 62:91-92 (1966).
                                   184

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The levels of parathion in the soil had declined considerably by the
end of the first year.  The rate of disappearance vas much slower the
second year, and the decline curves indicate very little further dis-
appearance of residues beyond the third year.  Six years after appli-
cation of the 45.67. concentrates, parathion residues ranging from
9,330 to 15,370 ppm were still present in the upper 3 in. of soil.
Residues found in the 3-to 9-d.n. soil layer ranged from 9.48 to 9,900
ppm, while concentrations ranging from 0.1 ppm to trace amounts were
found in five different layers of soil ranging from 9 to 24 in. in
depth.  Residues from the dilute sprays disappeared more rapidly.
Where the Ix (0.03%) concentration had been applied, average parathion
levels after 5 years ranged from 0.6 to 1.2 ppm in the top 1 in. of
soil, and from 0.2 to 0.3 ppm in the 1- to 3-in. depth.  Where the 8x
(0.24%) concentration was applied, average residue levels after 5 years
were 0.4 to 1.5 ppm in the top 1 in. of soil, and from 1.2 to 3.60 ppm
in the t to 3-in. level.

     Monitoring studies - In the National Soils Monitoring Program for
pesticides, 1,729 samples of cropland soils from 43 states were col-
lected in 1969 (Wiersma et al., 1972b).!/ Of these, 66 samples were
analyzed for organic phosphate residues, and seven of the 66 (10.6%)
contained parathion residues ranging from 0.01 to 3.01 ppm, the mean
residue level being 0.06 ppm.  One hundred ninety-nine samples of non-
cropland soil were also obtained, but none of these were analyzed for
organophosphate residues.

     In the National Soils Monitoring Program for Pesticides in 1970
(Crockett et al., 1970)2/ soil and crop samples,were collected from
1,506 cropland sites in 35 states.  Pesticide use records indicated
that parathion was used at 20 of 1,346 sites sampled, that is, 1.49%
of all sites.  No analyses of soil samples for parathion residues are
reported.  Samples of alfalfa, field corn kernels, cotton stalks and
green bolls, grass hay, field corn stalks, cotton seeds, mixed hay,
and soybeans (beans) were analyzed for organophosphate residues.
 If Wiersma, G. B., H. Tai, and P. F. Sand, "Pesticide Residue Levels
     in Soils, FY 1969 - National Soils Monitoring Program," Pest.
     Monit. J.f 6(3):194-228 (December 1972b).
 2/ Crockett, A. B., G. B. Wiersma, H. Tai, W. G. Mitchell and P. J.
     Sand, "National Soils Monitoring Program for Pesticide Residues -
     FY 1970," U.S. Environmental Protection Agency, Technical Services
     Division, unpublished manuscript (1970).
                                   185

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Parathion residues  found were nondetectable in most instances; in some,
their mean concentration was 0.01 ppm or less.

     Wiersma et al.   (1972a)i/ monitored pesticide residues in commer-
cially grown onions and in the soil on which these onions were grown in
1969.  A total of 76  sites in 10 major onion producing states were
sampled.  According to pesticide use records, parathion had been used
on 34.4% (36.4%) of the farms sampled, at an average rate of 1.64 Ib
Al/acre.  However, parathion residues (ranging from 0.02 to 2.55 ppm,
averaging 0.22 ppm) were found in 51.5% of the soil samples.  In most
instances, the average amount of residue detected was considerably less
than the amount applied when converted to pounds AI per acre.  Despite
the high residue levels in the soils, no residues of parathion (or of
any of the other pesticides) were detected in the onion samples.

     Stevens et al. (1970).?-' reported on a pilot study conducted nation-
wide at 51 locations in 1965, 1966, and 1967 to determine pesticide
residue levels in soil.  Samples were collected from 17 areas in which
pesticides are used regularly, 16 areas with a record of at least one
pesticide application, and 18 areas with no history of pesticide use.
This study was apparently aimed primarily at persistent chlorinated
hydrocarbon pesticides; only those organophosphates that were amenable
to chlorinated pesticide clean-up methods were detected, and no serious
attempts were made to quantitate metabolites or oxygen analogs of the
organophosphates.  Pesticide use records indicated that parathion had
been used at a number of the sites sampled, but only one single detec-
tion of parathion is reported, i.e., a residue of 0.06 ppm in one of
seven fields sampled near Tulelake, California.

     The data on parathion soil residues reported in the foregoing four
reports emanating from the National Soils Monitoring Program for Pesti-
cides are subject to question because in this program, soil samples are
being shipped and stored at room temperature until processed for analysis,
as reported by Stevens et al. (1970), and confirmed in a recent personal
communication to this reviewer by G. B. Wiersma.  No information is
I/ Wiersma, G. B., W. G. Mitchell, and C. L. Stanford, "Pesticide
     Residues in Onions and Soil - 1969,"  Pest. Monit. J.. 5(4):
     345-347 (March 1972a).
2_/ Stevens, L. J., C. W. Collier, and D. W. Woodham, "Monitoring Pesti-
     cides in Soils from Areas of Regular, Limited, and No Pesticide
     Use," Pest. Monit. J., 4(3):145-164 (December 1970).
                                 186

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given in these reports on the relationships between time of pesticide
application, time of sampling, and time of processing and analysis of
the samples.  No information is available on the effects of shipping
and storage of the samples on the parathion residues that may have been
present at the time of sampling.

     Applegate (1970)—' collected samples of soil, vegetation, birds,
rodents, and lizards from a large area of the Big Bend National Park,
Texas, and analyzed them for insecticide residues.  Samples were
placed in an ice chest as quickly as possible after collection, main-
tained under refrigeration, then taken to Presidio, Texas, 3 to 5 days
later where they were placed in deep freezers and held for 10 to 14
days in frozen storage until processing and analysis.  Parathion resi-
dues were found in 1 out of 9 samples of surface soil (0.01 ppm); in
1 out of 9 samples of leather stem, Jatropha dioica (0.01 ppm); in  2
out of 20 samples of muscle tissue of rodents (0.04, 0.11 ppm); in 3
out of 19 samples of whole lizards (0.01, 0.01, 0.10 ppm); and in 6 out
of 19 samples of bird muscle (0.01 to 0.21 ppm).  There were no known
direct applicators of parathion in the park.  The nearest areas using
insecticides are all south of the park in Mexico where parathion and
other pesticides have been applied routinely to cotton fields.  It is
not known how the specimens that were found to contain parathion resi-
dues acquired these.  The purpose of this study was to establish a
baseline  for future investigations to show possible changes in the
level of pesticide pollution of this park.
     The California Department of Water Resources (1969,
reported on pesticide concentrations in surface and subsurface drain
effluents in the San Joaquin Valley.  In 1969, 14 samples of surface
drain effluents 'were analyzed for organophosphorus  compounds.  Para-
thion was detected in three of these, at concentrations ranging from
6 to 500 ppt (parts per trillion), averaging 37 ppt in all samples
analyzed, 173 ppt in the positive samples.  In the same year (1969),
41 samples of subsurface drain effluents were analyzed for organo-
phosphate compounds.  Residues were detected in 19 of these, but no
identification was made of specific pesticides involved.
If Applegate, H. G., "Insecticides in the Big Bend National Park,"
     Pest. Monit. J.. 4(1):2-7 (1970).
2_/ California Department of Water Resources^  San Joaquin Valley Drain-
     age Monitoring Program, 1969 Summary, Sacramento, California (1969)
     (In:  Li and Fleck, op. cit., 1972.)
3_/ California Department of Water Resources,  San Joaquin Valley Drain-
     age Monitoring Program, 1970 Summary, Sacramento, California (1970)
     (In:  Li and Fleck, op. cit., 1972.)
                                 187

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     In 1970, 18 samples of surface drain effluents were analyzed for
organophosphate compounds.  Parathion was positively identified in one
of these; the concentration found was 190 ppt.  Of 60 samples of sub-
surface drain effluents analyzed for organophosphates, 10 were found
to contain residues of undetermined members of this group.

     These data show that only very small quantities of parathion and
of other organophosphate insecticides were present in these effluents.
The concentrations of these pesticides were somewhat higher in the sur-
face than in the subsurface drains.  These findings are in good agree-
ment with those of other authors, indicating  that organic phosphates
do not leach appreciably through soil profiles.


      The results of the 1972 National Soils Monitoring Program have not
yet been published, and a computer printout of the analytical  data by-
products is not expected to become available until later this  summer.
Thus, data from the program is not included in this review.

Summary -  Scientific data on the reviewed laboratory,  field and monitoring
studies on residues and fate of parathion show that the persistence of  this
chemical in the soil varies considerably, depending on a number of  factors.
Parathion residues in the soil degrade by chemical hydrolysis  as well as
by microbial action.  Parathion is strongly adsorbed by organic matter.
Thus adsorbed, the chemical becomes unavailable for insecticidal action,
and appears to be protected to a degree against degradation.   No data
are available on the fate of such adsorbed parathion residues; it  is
not known whether they eventually degrade, or if the under what condi-
tions they might become reactivated by desorption.  No information
appears to be available on the fate of the first degradation products,
especially _p_- nitrophenol and aminoparathion,  or regarding effects  on
organisms other than mammals and insects.

      Parathion soil residues resulting from crop protection uses  at
recommended dosage levels are apparently degraded in the soil, in most
cases, within a few weeks or months after application.   However, small
fractions of originally applied quantities may persist in the  soil  for
prolonged periods of time.  In the case of heavy soil contamination,
parathion soil residues have persisted for at least 16 years.
                                    188

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Parathion degradation in the soil appears to be temperature-dependent
and proceeds much more slowly in colder climates.  Thus, Canadian
investigators and one researcher from Australia who studied winter
application of parathion reported much slower decline rates than were
experienced in California.
     Monitoring studies in which samples to be analyzed for parathion
residues are not frozen promptly after collection are of questionable
value in determining environmental residues of this pesticide.  In
such studies, the time(s) and rate(s) of application in relation to
time of sampling should also be reported.

Residues in Water

Laboratory and Field Studies - Studies dealing with the fate of para-
thion residues in water are discussed in this section in approximate
chronological order.

     Lichtenstein et al. (1966)i/ studied the toxicity of parathion
and several other insecticides in water to mosquito larvae after per-
colation of the water through insecticide-contaminated agricultural
loam soil.  In distilled water, parathion caused 857. mortality of
mosquito larvae within 24 hr at 0.035 ppm.  When water was percolated
through soil treated with parathion at the rate of 50 ppm, parathion
residues were present in the water as determined by gas liquid chroma-
tography and 100% mosquito mortality.  Parathion was also present in
water percolated through soil treated at the rate of 1 ppm, when per-
colation took place on the day of treatment.  The 0.013 ppm of para-
thion was  found analytically in the percolated water.  Seventeen days
after soil treatment, the parathion residue in the soil was 0.089 ppm;
in the percolated water 0.001 ppm.  The percolated water was not toxic
to mosquito larvae at this time.  The authors conclude that the con-
tamination of water by insecticidal soil residues is to a large degree
a function of the water solubility of a particular insecticide.  Insec-
ticidal concentration in the soil and specific properties of a given
pesticide also are important.
I/ Lichtenstein, E. P., "Increase of Persistence and Toxicity of
     Parathion and Diazinon in Soils with Detergents," J. Econ. Entomol.,
     59(4):985-993 (1966).
                                  189

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     Graetz et al. (1970)!' Investigated the pathways and mechanisms
of parathion degradation in lake sediments.  Lake sediment samples
were taken from two lakes in Wisconsin, and the mechanisms and rates
of parathion degradation were determined in dry-heat-sterilized lake
sediment, in aerobic and anaerobic peptone solutions in a peptone
enriched sediment system, and in intact sediments from the two lakes.
Parathion was readily susceptible to microbial degradation in aerobic
and anaerobic environments.  Reduction of the nitro group to form
aminoparathion was a major microbial degradation pathway.  Under
aerobic, but not under anaerobic conditions aminoparathion was de-
graded further, apparently by another microbial process.  Parathion
degradation was slower in a slightly acid sediment than in a calcareous
one.  The authors conclude that the persistence of parathion in the
natural aquatic environment is affected markedly by microbial activity.
Without microbial activity, parathion would remain in the environment
for several months, while in biologically active (aerobic or anaerobic)
environments, it would be degraded in a matter of weeks.

     Eichelberger and Lichtenberg (1971)I/  investigated the persistence
of parathion and a number of other common pesticides in raw river water
over an 8-week period.  Aliquots of 10 pig/liter of parathion from a
freshly prepared 0.1% solution in acetone were injected into samples of
raw water from the Little Miami River, a relatively small stream re-
ceiving domestic and industrial wastes and farm runoff.  The dosed raw
river water was kept in the laboratory in closed glass containers at
room temperature, exposed to natural and artificial light.  The same
concentration of parathion was also added to distilled water in the
same manner.  In river water (alkalinity 98 ug/liter) 50% of the ori-
ginal concentration of parathion remained after 1 week, 30% after 2
weeks, less than 5% after 4 weeks.  With the use of thin layer chroma-
tography, it was observed that parathion was hydrolyzed to p_-nitrophenol
and diethylthiophosphoric acid.  Parathion remained stable in distilled
water for 3 weeks.
I/  Graetz, D. A., G. Chesters, T. C. Daniel, L. W. Newland, and G. B.
      Lee, "Parathion Degradation in Lake Sediments," J. Water Poll.
      Control Fed.. 42 (2, Pt. 2):R76-R94 (1970).
21  Eichelberger, J. W., and J. J. Lichtenberg, "Persistence of Pesti-
"     cides in River Water," Environ. Sci. Tech.,  5(6):541-544 (1971).
                                  190

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     Miller et al. (1966) investigated the persistence and movement
of parathion in cranberry bog irrigation waters.  Irrigation water
from a cranberry bog that had been treated with parathion at a rate
equal to 1 Ib Al/acre through overhead sprinkler irrigation was
sampled immediately after application, and every 24 hr thereafter
for a period of 96 hr.  The same experiment was repeated 14 days
later.  The authors report data representing the mean of the two
experiments.  Samples collected from an adjacent irrigation ditch
contained 750 ppb of parathion immediately after application; 60 ppb
after 24 hr; 25 ppb after 48 hr; 10 ppb after 72 hr; and 5 ppb after
96 hr.  In an associated drainage canal, 30 ppb of parathion were
found immediately after application, indicating water seepage through
a flood gate.  When this canal was resampled after 24 hr, 3.0 ppb of
parathion were detected.  Twenty-four hours after the application (but
at no other time period), trace amounts of parathion were also detected
at two locations 50 and 150 yd from the application site in the drain-
age canal down from the point where seeping irrigation water would
enter the canal waters.

     Schaefer and Dupras (1969)—  studied the effects of water quality,
temperature and light on the stability of parathion used for mosquito
control.  Samples of pasture water from pastures with a history of
mosquito control difficulties in alkaline soils in two California
counties were collected and passed through a coarse filter to remove
larvae and large pieces of organic matter.  The 150-ml samples of
pasture water and distilled water in glass jars were treated with para-
thion from a 0.15-ug/ml acetone solution to give a concentration of
0.1 ppm of the insecticide, the concentration normally encountered in
pasture water following application of 0.1 Ib Al/acre.  The jars were
moved to the field and placed into pasture water to expose them to the
same conditions of color, temperature and natural solar radiation as
field pasture water.  Both pasture and distilled water samples were
extracted after 0, 2, 4, and 8 hr of exposure.  Parallel tests were
carried out in the laboratory where samples were kept in the dark and
at constant temperatures of 24 and 38°C.  Water quality had little,  and
light had no, effect on the stability of parathion.  This insecticide
was very stable both under field and laboratory conditions and was only
slightly influenced by temperature.  After 8 hr, there was 10% more
loss of AI at 38 than at 24°C.
I/ Schaefer, C. H., and E. Dupras, Jr., "The Effects of Water Quality,
     Temperature and Light on the Stability of Organophosphorus
     Larvicides Used for Mosquito Control," Proc. Papers Ann. Conf.
     California Mosquito Control Assoc.. 37:67-75 (1969).
                                  191

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     Paris and Lewis (1973)!/ recently presented a rather brief, but
fairly complete review of the current extent of knowledge on the chem-
ical and microbial degradation of 10 selected pesticides, including
parathion, in aquatic systems.  They briefly cite many of the research
studies reviewed in greater detail in this report, but do not draw any
conclusions from their overview of the parathion data.

     Several authors from abroad have contributed data on parathion in
aquatic systems.  Greve (1972)£' identified parathion residues in Rhine
water at 0.01 to 0.1 ppb.  Quentin (1972a, 1972b)l*f!/ dealt with the
analytical, decontamination, and hygienic problems associated with the
presence of residues of parathion and other pesticides in water, in-
cluding drinking water supplies.  Adoption of a reduced maximum allow-
able concentration of parathion is being urged in West Germany.  Pesti-
cide contamination of surface waters must be monitored more closely in
the future as the use of surface water for drinking water purposes in-
creases.  The author emphasizes that maximum allowable concentrations
of single pesticides may be inadequate when several pesticides are
present in the same water.

     Manescu (1971)—  observed a decreased rate of oxygen consumption
by the self-purifying bacterial flora in surface water samples follow-
ing treatment with 100 mg/liter of parathion.  Oxygen consumption was
determined by the micromanometric Warburg procedure.  Compared to other
pollutants, metals, cationic detergents, or chlorine, pesticides ranked
low in their inhibitory action on the oxygen consumption of the bacteria,

     The reports reviewed in this section indicate, and the recent
literature search by Paris and Lewis (1973) confirms,that relatively
little information is available on the persistence and fate of
parathion residues in water, especially under actual field conditions.
I/ Paris, D. F., and D. L. Lewis, "Chemical and Microbial Degradation of
     Ten Selected Pesticides in Aquatic Systems," Residue Rev., 45:95-
     124 (1973).
2/ Greve, P. A., "Toxic Organic Trace Pollutants in Surface Water,"
     Chem. Weekblad. 41(68):11, 13, 15 (1972).
3/ Quentin, K. E., "Pesticides in Water - Determination, Removal, and
"~    Limiting Values," Chem. Ing. Tech.. 44(20):1172-1176 (1972a).
4/ Quentin, K. E., "Evaluation and Significance of Residue Values
     from the Viewpoint of the Water Biocenosis and Drinking Water
     Quality," Schriftenr. Ver. Wasser-Boden-Lufthyg.. 34:19-28 (1972b).
5_/ Manescu, S., "The Value of the Manometric Procedure in Studying the
     Chemical Micropollutant Action Potential on the Self-Purifying Water
     Flora," Igiena 20(5):275-286 (1971).
                                192

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Monitoring Studies - Dupuy and Schulze (1972)—' and Achulze et al.   (1973)!/
reported a maximum of 1 ppb parathion In routine water monitoring.   Butler
(unpublished)±' found a maximum of 170 ppb parathion in several marine  fish
along the Atlantic and Gulf coasts.

Residues in Air

      There is little information available on the origin, presence  and
persistence of parathion residues in air.

      Harris and Lichtenstein (1961)—  exposed cages vinegar flies  (Drosophila
melanogaster) and houseflies (Musca domestica) to vapors from soils  that had
been treated with parathion in the laboratory or in the field.  In the
laboratory tests, quartz was treated at the rate of 4 ppm of parathion.
There was no mortality of the insects that were kept in screened cages  above
the parathion-treated sant for periods of 6 or 24 hr.  Under the same, con-
ditions, 100% mortality was obtained with several other insecticides,
demonstrating the method's validity.  Lichtenstein and Schulz  (1970)A'
investigated the volatilization of parathion and other insecticides  from
eight different substrates.  It was generally assumed that low water solubility
and a relatively high vapor pressure would enhance volatilization from  aqueous
substrates.  However, no direct relationships were established by experimental
results between water solubility of a particular compound and its volatiliza-
tion.  Glass beads, tap water, soil water, algae in nutrient media, buffer
solution, buffer solution plus 0.1% detergent, silt loam and silt loam
containing 0.1% detergent were treated with   C-labeled parathion.  The
material volatilized within 24 hr was collected in a vapor trap and deter-
mined.  The volatilization rate of parathion was very low, ranging from
0.07% of the applied dose from the soil with or without the detergent, to
1.67% of the applied does from the buffer solution containing detergent.
Volatilization rates from the other substrates were intermediate between
these two extremes.

      Sandi (1958)—  studied the effects of direct sunlight compared to
dark conditions on parathion in a 2 x 10"^ M solution in a barbiturate buffer
at pH 8.0.  The results observed by two different analytical methods show
that parathion is photochemically reduced, presumably to the corresponding
p_-amino compound.
I/  Dupuy, A. J., and J. A. Schulze, Selected Water-Quality Records for Texas
      Surface Waters, 1970 Water Year.  Texas Water Development Board,
      Report 149, Austin, Texas (1972).
2J  Schulze, J. A., D. B. Manigold and F. L. Andrews, "Pesticides in Selected
      Western Streams - 1968-71, Pesticide Monitoring J., 9(2) 124-135 (1973).
3/  Butler, P. A., Unpublished report on Environmental Protection Agency
      National Estuarine Monitoring Program.
4/  Harris, C. R., and E. P. Lichtenstein, "Factors Affecting the Volitilization
      of Insecticidal Residues from Soils," J. Econ. Entomol., 54(5):
      1038-1045 (1961).
5_/  Lichtenstein, E. P., and K. R. Schulz, "Volatilization of Insecticides
      from Various Substrates," Agr. Food Chem.. 18(5):814-818 (1970).
6/  Sandi, E., "Reduction of Parathion Induced by Light," Nature. 181:499
      (1958).

                                   193

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     Stanley et al.  (1971)—  conducted a pilot study to establish a
system for measuring the extent of atmospheric contamination of the
air by pesticides in nine localities throughout the United States.
Samples were analyzed for 19 pesticides and metabolites, including
parathion.  Parathion was found in only one of the nine sampling loca-
tions, i.e., Orlando, Florida.  At that location, 37 samples contained
detectable amounts of parathion, the maximum level found being 465 ng/
cu m of air.  The majority of the Orlando air samples contained para-
thion levels ranging from about 10 to 25
                               ") I
     Tessari and Spencer (1971)—' analyzed air samples from human
environments in the Greeley, Colorado, area for pesticide residues.
Nylon chiffon cloth screens were exposed to the atmosphere for 5 days,
after which residues were extracted from them with suitable solvents
and determined by gas chromatographic analysis.  Screens were deployed
inside and outside 12 homes of men occupational ly exposed to pesticides,
including parathion (farmers and pesticide f emulators) .  Samples were
collected monthly for 1 year.  Parathion residues were found in a sur-
prisingly high number of cases from test screens exposed for 5 days at
a time.  In the positive indoor samples, parathion residues ranged
from 0.03 to 9.60 ug/m2 of filter; the means were 0.26 ug/m2 for the
farmers, 2.24 for the f emulators.  The authors point out that these
results are surprising because "parathion is volatile and has a rela-
tively short environmental half -life.  The farmer group had little or
no use of parathion, yet the occurrence of parathion in their environ-
mental samples, especially housedust and inside air samples, was high."
The outside air levels of parathion were very similar for both types
of homes sampled (means 0.75 and 1.11 ug/m , respectively; range 0.0 to
12.92 ug/m2).
I/ Stanley, C. W., J. E. Barney II, M. R. Helton, and A. R. Yobs,
     "Measurement of Atmospheric Levels of Pesticides," Environ.
     Set. Tech., 5(5):430-435 (1971).
2j Tessari, J. D., and D. L. Spencer, "Air Sampling for Pesticides
     in the Human Environment," J. Assoc. Offlc. Anal. Chem., 54(6):
     1376-1382 (1971).
                                   194

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      Search of the literature and of other information sources failed
to yield additional data on parathion air residues.   The reports reviewed
above indicate that parathion residues may be present in air,  but these
very limited data leave open many important questions, including origin
of such air residues, relationships to parathion use and handling patterns
in the area, persistence and transport patterns of such residues in air,
and their significance to human and environmental health.

Residues in Nontarget Plants

      Search of the literature failed to yield any reports on  parathion
metabolism or residues in or on nontarget plants.  Fukuto and  Sims
(1971)—' state in a recent text on the metabolism of insecticides and
fungicides:  "Surprisingly few Investigations have been carried out on
the metabolism of parathion and related compounds in plants in spite
of its wide usage on a variety of crops."

     Joiner and Baetcke (1973)—' studied the persistence of parathion
on cotton and identified its photoalteration products.    ^C-labeled
parathion was applied to cotton four times in  three  successive weeks
in four environmental situations, i.e., environmental  growth  chamber,
greenhouse, controlled field exposure, and open  field.   After 28  days,
11.2 to 15.4% of the total radioactivity applied was recovered by
methanol extraction and was found to be 58 to  68% unchanged parathion.
There was a constant increase in photoalteration products,  paralleled
by a consistent decrease in *^C-parathion over time.   Photoalteration
products did not include any previously unreported metabolites.   In
this set of experiments, parathion was found to  be at  least seven  times
more persistent than previously reported on cotton, according  to  the
authors.
I/  Fukuto, T. R., and J. J, Sims, "Metabolism of Insecticides and
      Fungicides," Pest. Environ.. R. White-Stevens (ed.) Vol. I, Parti,
      Ch. 2, pp.147-155, Marcel Dekker, New York (1971).
2f  Joiner, R. L., and K. P. Baetcke, "Parathion:  Persistence on
      Cotton and Identification of Its Photoalteration Products,"
      J. Agr. Food Chem.. 21(3):391-396 (1973).
                                   195

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     Kilgore  et  al.  (1972)  studied the persistence of parathion follow-
 ing  treatment of field  plots  of grapevines  at  2,  4 and 8  Ib  Al/acre.
 Parathion residues in bark, leaves,  berries, and  soil were monitored
 at different  time periods  after application.   From these  field experi-
 ments  that were  conducted  in  1969 and 1971,  the following conclusions
 were drawn:   (a)  parathion  tends to stabilize  in  grape bark  for at
 least  15  months  at a level  of 25 ppm; (b) no degradation  of  the parent
 compound  occurs  on the  surface of grape plants or within  the tissue
 after  penetration; the  parathion-paraoxon ratio found in  the insecti-
 cide at the time of  application did not change over the entire experi-
 mental period; (c) rapid loss of parathion  occurs after application,
 mostly attributable  to  volatilization, which was  then followed by an
 increasingly  slower  rate of disappearance;  (d) parathion  penetrates
 cane bark and reaches wood as well as pith  tissues; and (e)  parathion
 translocates  via xylem  into the emerging buds  and the expanding new
 shoots.

     Further'tests on the  absorption and translocation of-parathion
 in roots  were conducted in bean, barley and grape plants. The re-
 sults  obtained in this  series of tests confirm reports of other authors
 that parathion actually penetrates and translocates in plants.  It  is
 suggested that the metabolites reported in  earlier studies to be present
 in foliage are due to microbial activity in the soil, and that no signif-
 icant  modification of parathion occurs in plant tissue.  Parathion  dis-
 appears quite rapidly from the surface of plants  after spraying. It
 is estimated  that over  90% of the initial deposit  is lost by vola-
 tilization during the first few days.  The  remainder is stabilized
 in the bark (in the  case of grapevine), or  penetrates into plant tissue.
 The  amount of parathion that  gains entry into  plants is persistent,
 not  subject to significant metabolic or chemical modification, trans-
 located within plants,  and to decline primarily as a result  of dilution
 by plant  growth. The authors conclude from their work and other studies
 that parathion appears  to  be  much more persistent in the  environment
 than previously believed.

 Bioaccumulation, Biomagnification

     Miller et al.  (1966)  found that mummichog (Fundulus  heteroclitus)
and mussels (Elliptic? complanatus), in a model  cranberry bog  containing
0.07  ppm parathion, within  24  hours had levels  of  1.68 and 0.99  ppm,
respectively.   The ambient  level of parathion in the water at the end
of 24 hours was 0.02  ppm.  After 144 hours the  ambient water  level was
0.002 ppm, mummichog, 0.22  ppm and mussels,  0.04 ppm.
                                  196

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     Metcalf (1972)—' states:  "Both the organophosphates and carbamates
are not persistent in soil and do not accumulate in body fat."

     Thus, experimental data on possible bioaccumulation and biomagni-
fication of parathion appear to be almost nonexistent.  However, the
physical, chemical, and biological properties of parathion make it
unlikely that biomagnification in food chains or food webs occurs,
and there is no evidence that it does.

Environmental Transport Mechanisms

     The data reviewed in the preceding sections of this report in-
dicate that under field conditions, volatilization appears to be one
important mechanism by which parathion may move away from the target
site after application.  Freed et al. (Unpublished data, quoted from
von RUmker and Horay, 1972)—' determined the propensity of parathion
for volatilization and leaching under simulated field conditions for
loam soils at 25°C at an annual rainfall of 59 in. (150 cm).  Vola-
tilization of pesticides under these conditions, i.e., from a porous,
sorptive medium (loam soil) in a nonequilibrium situation, is dif-
ferent from volatilization from an inert surface or from the chemical's
own surface.  Therefore, the environmental volatilization index
assigned to pesticides investigated in this manner may or may not
parallel a chemical's vapor pressure.  By this method, parathion
rated a volatilization index of 3, indicating an estimated median
vapor loss from treated areas of 4.45 Ib/acre/year.  This index number
indicates a relatively high propensity for volatilization from treated
fields, compared to many other pesticides.

     Leaching index numbers for pesticides indicate the approximate
distance that the chemical would move through the standardized loam
soil profile under an annual rainfall of .59 in.  (150 cm).   Under
these conditions, parathion rated a leaching index number of 2,
indicating movement of 4 to 8 in.
I/  Metcalf, R. L., "DDT Substitutes," Grit. Rev. Environ.  Contr..
      3(1^:25-59 (Ref:  110) (1972).
2/  von Rumker, R., and F. Horay,  Pesticide Manual,  Vol.  I, Depart-
      ment of State, Agency for International Development (1972).
                                 197

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     These volatilization and leaching index numbers for parathion
are in excellent agreement with many laboratory and field observa-
tions reviewed in the preceding sections of this report.

     It thus appears that volatilization and surface runoff adsorbed
on solids are the two most important environmental transport mech-
anisms for parathion.  Surface runoff as a solute in water is likely
to occur only very soon after application, before substantial adsorp-
tion on soil solids, especially on organic matter, has occurred.
Leaching of parathion through soil profiles does not occur readily,
and is not likely to result following field applications at rates
recommended for insect control.
                                 198

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                                  202

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                                 203

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                  SUBPART II.  D.   PRODUCTION AND USE


                                 CONTENTS



                                                                      Page

Registered Uses of Parathion	    213


  Federally Registered Uses 	   213
  State Regulations	237


Production and Domestic Supply of Parathion In the U.S	238


  Volume of Production 	    238
  Imports	239
  Exports	239
  Domestic Supply	240
  Formulations 	    240


Use Patterns of Parathion in the United States	241
  General	241
  Parathion Use Patterns by Region	244
  Parathion Use Patterns by Crops 	   244
  Parathion Uses in California 	  245
  Summary	251
                                     212

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     This subsection contains data on the production  and uses of parathion;
it is organized according to three subject areas:  registered uses, produc-
tion and domestic supply, and use patterns.

Registered Uses of Parathion

Federally Registered Uses - Parathion has a very broad  spectrum of effective-
ness against insects and mites.   It is registered  and recommended in  the
United States for use on a large number of crops,  including fruit, nut,
vegetable and field crops.  Tolerances for parathion  residues have been
established on about 100 raw agricultural commodities.

     All registered uses of parathion by crops,  target  pests, dosage  rates,
formulations, type of use, established tolerances, and  use, timing, and  pre-
harvest interval limitations are summarized in the "EPA Compendium of
Registered Pesticides," pages III-P-2.1 through 2.164.  This section  on
parathion, comprising 164 pages, makes up more than 15% of all  listings  of
all registered insecticides, acaricldes, molluscidles and  antifouling com-
pounds in Volume III of the EPA "Compendium of Registered  Pesticides."  This
fact illustrates the large number and variety of pest control uses  for which
parathion formulations are currently registered in the  U.S.

     The registered uses of parathion are detailed in this section  by a  set
of four tables:

         Table 29:  Parathion - Summary of registered Uses by Crops,
                    Application Rates, and Rate and  Time Registration.

         Table 30:  Pest Insects and Mites against which parathion is
                    recommended, in alphabetical order by common name.

         Tables 31 and 32:  Registered uses of one of the common formula-
                    tions of parathion, i.e., emulsifiable liquid containing
                    4 Ib of active ingredient per gallon, by crops; insects
                    and other pests controlled on each crop; recommended
                    dosage rates; and general and specific directions for,
                    and limitations of use.

                    In these tables, rates of application are given in
                    terms of pints or quarts of formulated product per
                    acre or per volume of spray.  These rates are readily
                    convertible into active ingredient units.
                                     213

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      TABLE 29.  PARATHION - SUMMARY OF REGISTERED USES BY CROPS,  APPLICATION RATES,

                                AND RATE AND TIME RESTRICTIONS.

Target crops
Rate per Maxium
application permissible
AI rate.
(Ib. AI) (Ib./acre)
Minimum time, last treatment
to harvest.
(days)

Agricultural crop
Alfalfa
Almonds A/

Apples

Apricots

Artichokes
Avacados
Barley
Beans

(soil appl.)
Beets

(soil appl.)
Blackberries
(soil appl.)
Black-eyed peas
(soil appl.)
Blueberries
Boy senberr ies
(sell appl.)
Broccoli

(soil appl.)
Brussels sprouts

(soil appl.)
Cabbage


(soil appl.)
Cantaloupes
(soil appl.)
Carrots
(soil appl.)
Cauliflower

0.25-0.8/A
0.25-0.5/100gal. 2.6
1.0-2.6/A
0.12-0.5/100gal. 6.0
0.3-3.0/A
0.15-0. 5 /lOOgal. 3.6
1.0-3.0/A
0.35-0. I/A
0.18-0.37/100gal. 2.5
0.25-0.75/A
0.25-0.8/A

5.0-6.0/A
0.15-0.6/A

2.0-6.0/A
0.11-1.0/A
1.0/A
0.25-0.5/A
3.0-4.0/A
0.25-0.5/A
0.15-1.0/A
1.0/A
0.15-1.0/A

3.0-6.0/A
0.15-1.0/A

3.0-6.0/A
0.15-1.0/A


3.0-6.0/A
0.15-0.5/A
3.0-6.0/A
0.2-0.6/A
2.0-5.0/A
0.15-1.0/A

15days thru 0.8 Ib/A
thru 2.6 Ib/A

lAdays thru 6.0 Ib/A

14days thru 3.6 Ib/A

7days thru 1.0 Ib/A
21days thru 2.5 Ib/A
ISdays thru 0.85 Ib/A
7days thru 0.5 Ib/A
15days> 0.5 thru 0.8 Ib/A

ISdays thru 0.6 Ib /A
21days thru 0.6 Ib/A If

ISdays thru 1.0 Ib/A

ISdays thru 0.5 Ib/A

14days thru 0.5 Ib/A
ISdays thru 1.0 Ib/A

7days thru 0.5 Ib/A
21days>0.5 thru 1.0 Ib/A

7days thru 0.5 Ib/A
21days 0.5 thru 1.0 Ib/A

7days thru 0.25 Ib/A
10days>0.25 thru 0.5 Ib/A
21days>0.5 thru 1.0 Ib/A

7days thru 0.5 Ib/A

ISdays thru 0.6 Ib/A

7days thru 0.5 Ib/A
    (soil appl.)
3.0-6.0/A
                                                               21days   0.5  thru 1.0  Ib/A
Source:  U.S. Environmental Protection Agency, EPA Compendium of Registered Pesticides.
  Vol. Ill, (1973).
                                           214

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                                    Table 29.   (Continued)
Celery


     (soil appl.)
Cherries

Citrus

Clover
Collards

     (soil appl.)
Corn

     (soil appl.)
Corn (sweet)
     (soil appl.)
Cotton
Cow peas
Cranberries

Cucumbers

     (soil appl.)
Currants
Dewberries
Eggplant
     (soil appl.)
Endive
  (Escarole)

     (soil appl.)
Figs
Filberts!/

Garlic
Gooseberries
Grapefruit

Grapes

Grass (forage)
Hops
Rale

     (soil appl.)
Kohlrabi

Kumquats

Lemons
0.15-0.75/A
3.0-5.0/A
0.11-0.5/100gal.         2.0
0.4-1.4/A
0.0625-2.0/100gal.       4.0
1.0-10.0/A              10.0
0.12-0.75/A
0.15-0.5/A

3.0-4.2/A
0.16-0.75/A
0.015/1,OOOsq.ft.
1.0-6.0/A
2.0-5.0/A

0.1-1.0/A
0.45/A
0.5-1.0/100gal.          1.0
0.5-1.0/A
0.1/5xlO*cu.ft.
0.15-0.5/A
3.0-4.2/A
0.11-0.8/A
0.2-0.5/A
0.2-0.6/A
3.0-5.0/A
0.1/5x100 cu.ft.

0.35-0.5/A
3.0-4.2/A
0.25-0.5/100gal.         2.5
0.25/100gal.             2.5
0.4/A
0.25-0.5/A
0.11-0.8/A
0.0625-2.0/100gal.       4.0
1.0-10.0/A               10.0
0.25-1.0/lOOgal.         2.5
0.25-2.5/A
0.25-0.8/A
0.25-0.8/A
0.15-0.5/A

3.0-5.0/A
0.2-1.0/A

0.0625-2.0/100gal.       4.0
1.0-10.0/A               10.0
0.0625-2.0/100gal.       4.0
1.0-10.0/A               10.0
ISdays thru 0.25 Ib/A
21days3T 0.25 thru 0.5 Ib/A
30days>- 0.5 thru 0.75 Ib/A

14days thru 2.0 Ib/A

I4days thru 4.0 Ib/A
SOdays^- 4.0 thru 10.0 Ib/A
ISdays thru 0.8 Ib/A
 7days thru 0.25 Ib/A
10days2" 0.25 thru 0.5 Ib/A

12days thru 1.0 Ib/A
 7days thru 1.0  Ib/A
ISdays thru 0.45 Ib/A
ISdays thru 0.8  Ib/A
SOdays^ 0.8  thru 1.0 Ib/A
ISdays thru 0.1/SxlO4 cu.ft.l/
ISdays thru 0.5  Ib/A

30days thru 0.8  Ib/A
ISdays thru 0.5  Ib/A
ISdays thru 0.6  Ib/A

21days70.il  thru 5x10 cu.ft.-/

21days thru 0.5  Ib/A

30days thru 2.5  Ib/A
       thru 2.5  Ib/A

ISdays thru 0.5  Ib/A
ISdays thru 0.8  Ib/A
lAdays thru 4.0  Ib/A
30days ^4.0  thru 10.0 Ib/A
14days thru 1.5  Ib/A
    1.5 thru 2.5  lb/Al/
ISdays thru 0.8  Ib/A
ISdays thru 0.8  Ib/A
  7days thru 0.25 Ib/A
lOdays    0.25 thru 0.5 Ib/A

  7days thru 0.8  Ib/A
21days^ 0.8  thru 1.0 Ib/A
14days thru 4.0  Ib/A
30days:=- 4.0  thru 10.0 Ib/A
14days thru 4.0  Ib/A
30daysxr4.0  Ib. thru 10.0 Ib/A
                                             215

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                                    Table 29.  (Continued)
 Lettuce
     (soil appl.)
 Limes
 Loganberries
 Mangoes
 Melons
     (soil appl.)
 Mustard greens

 Nectarines

 Oats
 Okra
 Olives
 Onions
     (soil appl.)
 Oranges

 Pastures see Grass
     (soil appl.)
 Pastures
     (irrigated)
 Peaches

 Peanuts
     (soil appl.)
 Pears

 Peas

     (soil appl.)
 Pecans

 Peppers
     (soil appl.)
 Pineapples
     (preplant  dip)
 Plums/Prunes

Potatoes
    (soil  appl.)
Pumpkins
Quince
   0.1/5x10* cu.ft.
   0.25-0.5/A
   3.0-6.0/A
   0.0625-2.0/100g
   0.25-1.0/A
   0.5/100gal.
   0.15-0.5/A
   4.0-6.0/A
   0.15-0.5/A

   0.18-0.5/100gal.
   0.6-2.0/A
   0.25-0.75/A
   0.25-0.75/A
   0.25-0.62/100gal.
   0.2-0.8/A
   0.38-0.6/A
   0.0625-2.0/100gal.
   1.0-10.0/A
(forage)
   0.5-1.0/A
   O.I/A

   0.18-0.5/100gal.
   0.6-2.0
   0.2-0.5/A
   2.0-3.0/A
   0.15-0.38/100gal.
   0.4-1.0/A
   0.25-0.5/A

   3.0-6.0/A
   0.25-0.38/100gal.
   0.6-0.7/A
   0.15-0.8/A
   5.0-6.0/A
   0.45-0.75/A
   0.15/100gal.
   0.25-0.5/100gal.
   1.0-1.5/A
   0.25-1.0/A
   2.0-6.0/A
   0.2-0.5/A
   0.3-0.38/100gal.
10.0

 3.0
 5.0
 5.0
 4.0
10.0
 5.0
 3.6
 5.4
 4.0
21days 0.1 Ib. thru 5x10* cu.ft.i'
 7days thru 0.5 Ib/A (head)
lAdays thru 0.25 Ib/A (bibb & head)
21days^> 0.25-0.5 Ib/A (bibb & head)

14days thru 4.0 Ib/A
ISdays thru 1.0 Ib/A
21days thru 3.0 Ib/A
 7days thru 0.5 Ib/A

 7days thru 0.25 Ib/A
IQAaya^ 0.25 thru 0.5 Ib/A
14days thru 4.0 Ib/A
21days thru 2.5 Ib/A*/
ISdays thru 0.75 Ib/A
21days thru 0.75 Ib/A

ISdays thru 0.8 Ib/A5-/

14days thru 4.0 Ib/A
30daysjx" 4.0 thru 10.0 Ib/A
 7days thru 0.1 Ib/A

 7days thru 0.116/A

14days thru 4.0 Ib/A
21days thru 2.5 lb/A±'
ISdays thru 0.5 Ib/A

14days thru 3.6 Ib/A

lOdays thru 0.5 Ib/A (peas)
ISdays thru 0.5 Ib/A (forage)

ISdays thru 5.4 Ib/A

ISdays thru 0.8 Ib/A

 7days thru 0.75 Ib/A

14days thru 4.0 Ib/A

 Sdays thru 1.0 Ib/A

lOdays thru 0.5 Ib/A
14days thru 3.6 Ib/A
                                            216

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                                       Table 29.   (Continued)
    Radishes
    Raspberries
    Rice
    Rutabagas
        (soil appl.)
    Safflower
    Sorghum
    Soybeans
        (soil appl.)
    Spinach
        (soil appl.)
    Squash
    Strawberries

        (soil appl.)
    Sugar beets
        (soil appl.)
    Sugarcane
        (soil appl.)
    Sweet potatoes
        (soil appl.)
    Swiss chard
    Tangelos/
       Tangerines

    Tobacco

        (soil treat)
    Tomatoes

        (soil appl.)
    Turnips

        (soil appl.)
    Vetch
    WalnutsiH/

    Watermelons
        (soil appl.)
    Wheat
0.1/5xl04cu.ft.
0.2-1.0/A
0.094-0.I/A
0.15-0.75/A
3.0-5.0/A
0.5/A
0.25-1.01 Ib/A
0.2-0.8/A
3.0-4.2/A
0.2-0.5/A
4.0-6.0/A
0.15-0.5/A
0.2-0.8/A
    1.0/Al/
0.4-5.0/A
0.3-0.8/A
4.0-5.0/A
2.0-6.0/A

0.5-1.0/A
2.0-4.0/A
0.2-0.5/A
0.0625-2.0/100gal.

1.0-10/A
0.01-0.05/lOOsq.ydJi'
0.15-0.5/A
2.0-6.0/A
0.1/5x10 sq.ft.
0.25-1.0/A
3.0-6.0/A
0.25-0.5/A

3.0-5.0/A
0.25-0.8/A
0.075-0.5/100gal
0.3-0.8/A
0.2-0.5/A
3.0-4.0/A
0.25-0.8/A
 4.0
10.0
 5.0
               ISdays thru 0.1/5xl04 cu.ft.-2/
               ISdays thru 1.0 Ib/A
                Iday  thru 0.1 Ib/A
                7days thru 0.75 Ib/A

                      thru 0.5 Ib/A6-/
               12days thru 1.0 Ib/A
               20days thru 0.8 Ib/A

               14days thru 0.5 Ib/A

               ISdays thru 0.5 Ib/A
               14days thru 0.8 Ib/A
               ISdays thru 0.8 Ib/A
ISdays thru 11.0 Ib/A

21days thru 0.5 Ib/A
14days thru 4.0 Ib/A

 3days^>4.0 thru 10.0 Ib/A
 Sdays thru 0.5 Ib/A (by priming)
ISdays thru 0.5 Ib/A (by cutting)

lOdays thru 0.1/104 sq.ft.^/
lOdays thru 1.0 Ib/A

 7days thru 0.25 Ib/A
lOdays^ 0.25 thru 0.5 Ib/A

ISdays thru 0.8 Ib/A
ISdays thru 0.8 Ib/A

 7days thru 0.5 Ib/A

ISdays thru 1.0 Ib/A
Ornamentals

    Gladiolus  (soil appl.)

    Flowering plants

               (soil appl.)
        5.0/A

        0.15-0.75/A

        2.0-5.0/A
                                               217

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                                       Table 29.   (Continued)
Woody Shrubs, Trees and Vines

    Christinas trees

    Shrubs/Trees/Vines

         (soil appl.)

Greenhouse Plants

    Chrysanthemums

    Lilies

    Greenhouse
      ornamentals

Aquatic Areas

    Standing water
0.25/100gal.

0.15-0.75/A

2.0-5.0/A



0.1/5xl04 sq.ft.

0.1/5xl04 sq.ft.

0.1/5xl04 sq.ft.




0.04/A
For commercial use only.

For commercial use only.

For commercial use only.




See restrictions listed in Compendium.
Notes:

    1.  Do not apply after hulls begin to open thru 2.6 Ib/A.

    2.  30 day spray/harvest interval if tops are to be used as food or feed.

    3.  Apply dosages^=^1.5 thru 2.5 Ib./A before fruit is the size of buckshot or after
          harvest.

    4.  California:  Do not apply 5.01b/A between Jan.1 and harvest.

    5.  Do not apply later than Aug. 1 through 5.0 Ib/A.

    6.  Do not apply after flowering through 5.0 Ib/A.

    7.   For post-harvest only.

    8.   Seed bed treatment.

    9.   For commercial greenhouse use only.

   10.   Do not apply after husks open through 5.0 Ib/A.
                                               218

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               TABLE 30.  PEST INSECTS AND MITES AGAINST WHICH
                       FARATHION IS RECOMMENDED
                  (IN ALPHABETICAL ORDER BY COMMON NAMES)
 Alfalfa caterpillar
 Alfalfa looper
 Alfalfa seed chalcid
 Alfalfa weevil
 American cockroach
 American plum borer
 Ants
»Aphids
 Apple flea veevil
 Apple lace bug
 Apple maggot
 Apple redbug
 Armyworm
 Artichoke plume moth
 Asiatic garden beetle
 Avocado lace bug
 Avocado leafhopper
 Azalea leafminer
 Bagworm
 Banded cucumber beetle
 Beet armyworm
 Bean leaf beetle
 Beet leafhopper
 Bean leafroller
 Black grass bugs
 Black vine weevil
 Blackheaded fireworm
 Black vine weevil
 Blister beetles
 Blossom anomala
 Blossom weevils
 Blueberry maggot
 Boll weevil
 Boll worm
 Cabbage looper
 Cankerworms
 Carrot rust fly
*Casebearers
 Catfacing insects
 Celery leaftier
 Cherry fruitworm
 Cherry maggot
 Chinch bug
 Citrus root weevil
 Climbing snails
 Clover head weevil
 Clover leaf weevil
 Codling moth
 Colorado Potato beetle
 Consperse stinkbug
Colias eurytheme
Autographa californica
Bruchophagus roddi
Hypera postica
Periplaneta americana
Euzophera semifuneralis
Family Formicidae
Family Aphididae
Rhynchaenus pallicornis
Corythueha caelata
Rhagoletis pomonella
Lygi de a mendax
Pseudaletia unipuncta
Platyptilia carduidactyla
Maladera castanea
Pseudacysta perseae
Idona minuends
Gracillaria azaleelia
Thyridopteryx ephemeraeformis
Diabrotica baiteata
Spodoptera exigua
Erynephala puncticollis
Circulifer teneJLlua
Urbanus proteus
Family Miridae
Otiorhynchus  sulcatus
Rhopobota naevana
Otiorhynchus  sulcatus
Family Meloidae
Anomala undulata
Anthonomus  spp.
Rhagoletis  mendax
Anthonomus  grandis
Heliothis  zea
Trichoplusia  ni
Family  Geometridae
Psila rosae
Family  Coleophoridae
Order Hemipter a/Heteroptera
Udea rubigalis
Grapholitha packardi
Rhagoletis  cingulata
Plissus  leucopterus
Pachnaeus  litus
Class Gastropoda
Hypera meles
Hypera punctata
Laspeyresia pomonella
Leptinotarsa decemlineata
Euschistus  conspersus
 Source:  List of pest Insects and mites from:  U.S. Environmental Protection
   Agency, EPA Compendium of Registered Pesticides,  Vol.  Ill (1973);
   scientific names from:  Supplement 13 to EPA Compendium, Vol.  III.
                                219

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                       Table 30. (Continued)
  Corn  earworm
  Corn  rootworms
  Corn  silk  fly
  Cotton  leafperforator
  Cotton  leafworm
  Cranberry  fruitworm
  Cranberry  tipvorm
  Crane flies
  Cri ckets
  Cucumber beetles
  Current borer
 *Cutworms
  Darkling beetles
  Diamondback  moth
  Earwigs
  European apple sawfly
  European Corn borer
  Eyespotted bud moth
  Fall  armyworm
  Fall webworm
  False celery leaftier
  False chinch bug
  Flea beetles
  Fruittree  leafroller
  Fuller rose  beetle
  Grape berry  moth
  Grape bud  beetle
  Grape leaffolder
  Grasshoppers
  Green clovervorm
  Green fruitworm
  Green June  beetle
  Greenhouse leaftier
  Harlequin  bug
  Hoplia beetles
  Hornworms
  Imported cabbageworm
 Japanese beetle
 Juniper webworm
 Katydids
  Lace bugs
 Leafhoppers
 Leaffooted bug
*Leafminers
*Leafrollers
*Leaftiers
 Lesser appleworm
 Lesser cornstalk borer
 Lesser peachtree borer
 Limabean pod borer
 Little fire ant
Heliothis zea
Diabrotica spp.
Euxesta stigmatias
Bucculatrix thurberiella
Alabama argillacea
Acrobasis vaccinii
Dasineura oxycoccana
Family Tipulidae
Family Gryllidae
Family Chrysomelidae
Synanthedon tipuliformis
Family Noctuidae
Family Tenebrionidae
Plutella xylostella
Family Dermaptera
Hoplocampa testudinea
Ostrinia nubilalis
Spilonota ocellana
Spodoptera frugiperda
Hyphantria cunea
Udea profundalis
Nysius ericae
Family Chrysomelidae
Archips argyrospilus
Pantomorus cervinus
Paralobesia viteana
Glyptoscelis squamulata
Desmia funeralis
Family Acrididae
Plathypena scabra
Lithophane antennata
Cotinis nitida
Udea rubigalis
Murgantia histionica
Hoplia
Family
Pieris
 spp.
Sphingidae
rapae
Popillia Japonica
Dichomeris marginella
Family Tettigoniidae
Family Tingidae
Family Cicadellldae
Leptoglossus phyllopus
Class Insecta
Class Insecta
Order Lepidoptera
Grapholitha prunivora
Elasmopalpus lignosellus
Synanthedon pictipes
Etiella zinckenella
Wasmannia auropunctata
                             220

-------
                      Table 30.  (Continued)
 Lygus bug
 Mealybugs
 Mellonworm
 Midges
*Mites
 Mosquitoes
 Obsure root weevil
 Omnivorous leaf roller
 Onion maggot
 Orangedog
 Orange worm
 Orange tortrix
 Oriental fruit moth
 Pameras
 Pandemis moth
 Peach bark beetle
 Peach twig borer
 Peachtree borer
 Pea moth
 Pea weevil
 Pearslug
 Pear psylla
 Pecan leaf casebearer
 Pecan nut casebearer
 Pepper maggot
 Pickleworm
 Pink scavenger caterpillar
 Plant bugs
 Plum curculio
 Potato psyllid
 Potato tuberworm, Splitowrm
 Psyllids
 Raspberry crown borer
 Readbanded leafroller
 Readnecked cane borer
 Readnecked peanutworm
 Rice leafminer
 Rindworms
 Rose chafer
 Saltmarsh caterpillar
 Sand wireworm
 Sapbeetles
 Sawflies
"Scales
 Seedcorn maggot
 Shothole "borer
 Sixspotted leafhopper
 Sorghum midge
 Sorghum webworm
 Sowbugs
Lygus spp.
Family Pseudococcidae
Diaphania hyalinata
Family Chironomidae
Class Acarina
Family Culicidae
Sciophithes obscurus
PIatynota stultana
Hylemya antiq.ua
Papilio cresphontes
Class insecta
Argyrotaenia citrana
Grapholitha molesta
Pachybrachius bilobata
Family Tortricidae
Philoeotri'bus liminaris
Anarsia lineatella
Sanninoidea exitiosa
Laspeyresia nigricana
Bruchus pisorum
Caliroa cerasi
Psy11a pyricola
Acrobasis Juglandis
Acrobasis caryae
Zonosemata electa
Diaphania nitidalis
Sathro'brota rileyi
Family Miridae
Conotrachelus nenuphar
Paratioza cockerelli
Phthorimaea operculella
Family Psyllidae
Bembecia marginata
Argyrota.enia velutinana
Agrilus ruficollis
Stegasta bosquella
Hydrellia griseola
Order Lepidoptera
Macrodactylus subspinosus
Estigmene acrea
Horistonotus uhlerii
Family Nitidulidae
Order Hymenoptera
Superfamily Coccoidea
Hylemya platura
Scelytus rugulosus
Macrosteles fascifrons
Contarina sorghicola
Gelama sorghiella
Order Isopoda
                            221

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    Table 31.   REGISTERED USES OF PARATHION EMULSIFIABLE LIQUID
             (A  LB ACTIVE INGREDIENT  PER GALLON) - CROPS AND
        OTHER USES, PESTS, DOSAGE RATES AND  USE LIMITATIONS^'
                NI ran
E-4
                                                 Hazards and Ingredients
                   INSCCIKIOC BY
                          Monsanto.
              Emulsifiable insecticide for
                controlling certain insects
                on the listed field, forage,
                fruit and vegetable crops.

              NOT FOR HOME USE

              Complete Directions for Use
                         EPA Reg. No. 524-132
              Use only according to these label instructions.
              READ "LIMIT OF WARRANTY AND LIABILITr BE-
                FORE BUYING OR USING. IF TERMS ARE NOT
                ACCEPTABLE RETURN AT ONCE UNOPENED.
              RESEALABLE BAG
                 TPull flaps apart to open.
                 Press along ridge to close.
STOP!  READ THE LABEL

  DANGER!     POISON
  Keep Out of Reach of Children
                                                         CAN KILL YOU
               ACTIVE INGREDIENTS:
                •Paratfiion: 0,0-diethyl 0-p-nHrophenyl
                 phospborothioate	45J%
                Aromatic petroleum derivative solvent .. 49.4%
               INERT INGREDIENTS:	 5JK
                                       100.0%
               •Equivalent to 4.0 Ibs. of 100%
                parathion per gallon.
               Combustible: Do net store or use near beat or opn
               HUM. In case of fire, use  water spray, foam, dry
               chemical or C02.
a/   Sample label  of Monsanto  Company, St.  Louis,  Missouri, EPA Reg.
       No.  524-132.
     This  formulation Is not currently marketed by Monsanto, but the
     label  is being made available  to Monsanto1s  formulator customers
     for parathion technical (J. M. Magner,  Communication, 10 May 1974.
                                       222

-------
                              Table  31.   (Continued)
    LIMIT OF WARRANTY AND LIABILITY
Monunto Company warrants that this material con-
forms to the chemical description on the libel ind
is ntsonabhr fit for the purposes referred to in the
directions for use. This product is sold subject to
the understanding that the buyer assumes all risks
of use or handling which may result in loss or dam-
tfe which are beyond the control of the seller, such
as for example incompatibility with other products.
the manner of its use or application, or the presence
of other products or materials in or on the soil or
crop. MONSANTO MAKES NO OTHER EXPRESS OR
IMPLIED  WARRANTY OF FITNESS OR MERCHANT-
ABILITY. The exclusive remedy of the user or buyer.
and tte limit of the liability of Monsanto Company
or any other seller for any and all losses, injuries or
damatts  resulting from the use or handling of this
product shall be the purchase price paid by the user
or buyer  for  the quantity of this product involved.
The buyer and all users are deemed to have accepted
the terms of this notice which may not be varied by
any verbal or written agreement
       CAM  KILL YOU BY  SB* CONTACT
    INt product an UK IN if fowled by knxb or
    ipilM or lebsfltd on stiff,  in eye or on cMftutf
    (tqrt t»et ttroutk dottti). 4«^B> .
                                    »
                          *
    00 NOT TOUCH
         CAM PU YOU  If BREATHED
    Wl product an kM |ta h* nporv nw» ma) or dint
    tnbneftoi.
    00 NOT BREATHE
         CM PU YOU IF SWALLOWED
    nil product  on kin you il iwflowtd MM in
    vnt Mmmti: ipny not or dutt ray bt MM if
                                                           00 NOT SWALLOW
 Precautions
    POISONOUS TO  FISH AND WILDLIFE
This product is toiic to fish and wildlife. Birds and
other wildlife in treated areas may be hilled. Keep
out of any body of water. Do not apply when weather
conditions favor  drift .from treated areas. Do  not
apply when runoff is likely to occur. Do not con-
taminate water by cleaning equipment or disposal
of wastes.
MSrOSAL OF EMPTY  CONTUMEI-Do not re-use
this container. Completely empty the contents and
bury the unused chemical at least 18 inches deep
• an isolated location away from water supplies.
Rinse out the inside of the container with water to
which has been added detergent and caustic soda.
Carefully discard the rinse solution  by burying at
least It inches deep in an isolated area away from
water supplies. Puncture and crush empty metal
container and bury at least  18 inches deep in a
supervised  public or private dump.

USE ONLY WHEN WEARING THE FOLLOWING
  PROTECTIVE EQUIPMENT AND CLOTHING
 (1)  Wear water-proof pants, coat hat, rubber boob
 or rubber overshoes. (2) Wear safety goggles. (3)
Wear mask or respirator approved by the U5. Bureau
•f Mines for parathion protection. (I) Wear heavy
 My. natural robber gloves.
           WORK SAFETY RULES
Keep alt unprotected persons and children away from
treated area or where there is danger of drift.
Do not rub eyes or mouth with hands. If you feel sick
in any way, STOP work and get help right away. Call
a doctor (physician), clinic or hospital—immediately.
Explain that the victim has been exposed to para-
thion and describe his condition. After first aid is
given (see Tint Aid Treatment Section) and if a doc-
tor cannot come, take victim to clinic or hospital.
IMPORTANT!  Before removing gloves, wash them
with soap and water. Always wash hands, face and
arms with soap and water before smoking, eating or
drinking.
AFTER WORK, take off all work clothes and shoes.
Shower,  using  soap and water. Wear only dean
clothes when  leaving job. Do not wear contaminated
clothing. Wash protective clothing and  protective
equipment with soap and water after each use. Res-
pirator should be cleaned and filter replaced accord-
ing to instructions included with respirator.

      •fc POISON SIGNS (Symptoms)
Parathion is a very dangerous poison. It rapidly en-
ters the body on contact with all skin surfaces and
eyes. Clothing wet with this material must be re-
moved immediately. Exposed persons must receive
 prompt medical treatment or they may die.

Work Safety Rules and Poison Signs (Symptoms)  9
                                                223

-------
                           Table   31.   (Continued)
  First Aid Treatment
 10
  Some of the signs and symptoms of poisoning ire:
  Headache,  nausea,  vomiting, cramps,  weakness,
  blurred  vision, pin-point pupils, tightness in chest
  labored  breathing, nervousness, sweating, watering
  of eyes, drooling or frothing of mouth and nose.
  muscle spasms and coma.

       +   FIRST  AID TREATMENT   +
  Call a doctor (physician), clinic or hospital immedi-
  ately. Explain that the victim has been exposed to
  parathion and describe  his condition.
  H breathing has stopped, start artificial respiration
  immediately and  maintain until doctor sees victim.
  If swallowed and victim is awake (conscious) make
  him vomit quickly. Induce vomiting by sticking finger
  down throat or by giving soapy or strong salty water
  to drink. Repeat until vomit is dear. Never give any-
  thing by mouth to an unconscious person. Have victim
  lie down and keep quiet. See doctor immediately
  ta ox of contact, immediately flush' eyes or skin
  with plenty of water for at least 15 minutes while
  removing contaminated clothing and shoes. See doc-
  tor immediately.
  ATROPINE IS AN ANTIDOTE.
  CONSULT PHYSICIAN FOR EMERGENCY SUPPLY.
  If symptoms or signs of poisoning include blurred
  vision, abdominal cramps, and tightness in the chest,
  do not wait for a doctor but give two atropine tablets
  (each 1/100 grain or 0.65 milligrams)  at once. (One
  tablet to children under five years of age.)
Prevent Injury
                                                                                                      12
               TO  PREVENT PERSONAL  INJURY AND POSSIBLE
               FATALITIES:
               Keep all persons and animals out of treated areas for
               48 hours.
               Vacated areas should not be re entered until drifting
               insecticide and  volatile residues have  dissipated.
               Do not use in any manner other than recommended
               on this label.
               To avoid excessive residues of parathion on food or
               forage crops, always observe the statements found
               under "Directions for Use," limiting the time before
               harvest when  parathion  may be applied.
               If  handled  indoors, provide mechanical exhaust
               ventilation.
               Do not apply or allow  drift to areas occupied by
               unprotected humans or  beneficial animals.
               Do not use or store in or around the home.  Keep out
               of reach of children and domestic animals. Do not
               store  near food or feed products.  Bury  spillage;
               dean up area with strong lye solution.
               This  product  is highly  toxic to  bees exposed to
               direct treatment or residues on  crops. Protective
               information may be obtained from your Cooperative
               Agricultural Extension Service.
             NOTE TO PHYSICIAN
Antidote—administer atropine sulfate in large doses,
TWO to FOUR mg. intravenously or Intramuscularly as
soon as cyanosis is overcome. Repeat at 5 to 10 min-
ute intervals until signs of  atropinization  appear.
2-PAM chloride is also antidotal and may be admin-
istered in conjunction  with atropine. DO NOT GIVE
MORPHINE  OR  TRANQUILIZERS. Parathion is a
strong chofinesterase inhibitor affecting the central
and peripheral nervous systems and producing car-
diac and respiratory  depression.  At  first  sign of
pulmonary edema, the patient should be given sup-
plemental oxygen and treated symptomatically. Con-
tinued absorption of the poison may occur and fatal
relapses have been reported after initial improve-
ment VERY CLOSE SUPERVISION OF THE PATIENT
IS INDICATED FOR AT LEAST 48 HOURS.
            POST  TREATED AREA
Consult your State Agricultural Extension Service or
Experiment Station regarding posting treated areas.
                     DIRECTIONS FOR USE
              Be sure to read the precautionary statements before
              using!
              This product is designed for application after dilu-
              tion with water and for use  by trained  operators
              using  airplane or power  ground  equipment  The
              hazards and precautions for handling the product in
              this container are equally applicable to it after dilu-
              tion with  water for spray application.  Add the con-
              centrate to the spray tank  while filling with water,
              and mix thoroughly either  by means of a tank  agi-
              tator or pump by-pass. For best results, thoroughly
              cover all surfaces to be treated with spray. Rates of
              app|ication given below should not be exceeded.
              Never  apply later than indicated to assure residue
              levels  at harvest  are below tolerances established
              by the Food and Drag Administration.
              Consult the State Agricultural Extension  Service or
              Experiment Station  for  specific recommendations
              regarding  application, dosage and timing of sprays.
              For application by ground  equipment add the de-
              sired amount of concentrate to sufficient  water to
              apply at least 3 gallons of water per acre. For appli-
              cation  by  aircraft, add the amount of concentrate
              desired per acre to  Vt to  3  gallons of water con-
              sistent with crop growth and good coverage. Greater
              quantities of water may be required  to give sufficient
              coverage of orchard trees.
Note to Physician
11
                                                         Directions for Use
                                                         13
                                             224

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                              Table  31.   (Continued)
Fnit Insects
                                          14
                  FRUIT
DO NOT USE TREATED CITRUS PEEL  FOR
FOOD PURPOSES.
CITRUS (Calfhraia)-Grapefruits. Kumqvats,
lemons. Limes, Oranges, Tinf does and Tangerines.
Sah-For  purple,  black, brown soft, California
no*, citricola, cottony-cushion and yellow scales, use
H to H pint in 100 pllons of water applied at petti
fall to prevent fruit scattering.
Mar amcts  Use 1 to 2 quarts in 100 pllons
of water for control of  the following additional
kneels infesting citrus:  climbing cutworms,  fruit
tree leaf rollers, katydids, omnivorous  leaf rollers,
Fuller rose  beetles,  pink scavenger  caterpillars,
orange tortrix,  orangeworms and Western tussock
moths. Do not  use more than 2H gallons of this
product per acre up to 30 days of harvest. Do not
tse more than 1  gallon  of this product per acre
from 30 days up to 15 days of harvest Consult agri-
cultural experimental authorities for specific recom-
mendations in your area.
CtnUS (fctas ifttr nan CaHforma)-€rapefniits,
Kumqoats, Lemons, Limes, Oranges, Tangeloes and
 Treat for mealybugs: chaff, cottony-cushion, Glover's,
 purple, Florida red, yellow, snow scales;  aphids;
 oranp dog and plant bugs, using H to H pint In 100
 pllons of water. For control of mites and whHeffies.
           Fruit Insects cont'd.
                                                     16
           control whHeflies, use H pint with 1 gallon of emul-
           sive oil concentrate in 100 gallons of water. To con-
           trol Florida red scales. Florida wax scales,  dictyo-
           spermum scales and  avocado leafhoppers. use %
           pint in 100 gallons of water. To control pumpkin bugs
           and mealybugs, use 'A to % pint in 100 pllons of
           water. To control latania scales, use % pint In  100
           pllons of water. Do not use more than 2H quarts
           of this product per acre.
            DO NOT APPLY TO  THE FRUITS  LISTED
            BELOW WITHIN  IS DAYS  OF HARVEST.
            CANEBEMUES (Raspberries, Loganberries. I
            berries and  Blackberries) - For control of two-
            spotted spider mites, use K pint per acre. For control
            of obscure and woods weevils, use at 1 quart per
            acre as a  post harvest application  to the soil or
            ground cover over roots of plants. For crown borers,
            use at 1 quart per acre but apply to crown area and
            lower canes.
            CMMBDMES—For control  ot fireworms,  fruit-
            worms, fa'pworms and Itcanium scales, use IK pints
            per acre.
            GOOSEBERRIES—f or control of currant aphids, use
            H to IVi pints per acre. For control of two-spotted
            spider mites, use  1  to I'A  pints  per acre. For
            currant borers, use I*/, pints per acre.
 ose tt to X pint with 1 gallon of emulsive oil concen-
 trate in 100 pllons of water. For controlling grass-
 hoppers, use 1 pint per acre. Thorough coverage is
 essential for best results. Do  not  use more than
 2tt pllons of this product per acre up to 30 days
 of harvest Do not use more than 1 gallon of this
 product per  acre from 30 days up to 15 days of
 b*Mu*4
 MiYCSL

 DO  NOT APPLY TO CURRANTS AND FIGS
 WITHIN 30 DAYS OF HARVEST.
 COMMITS—For control of currant aphids, use H
 to I'A pints per acre. For control of two-spotted
 spider mites, use 1  to  IV, pints  per  acre. For
 currant borers, use l'/i pints per acre.
 FIGS—for two-spotted and Pacific mites, use M to 1
 pint per 100 pllons of water. For fig scales, use 1
 pint per 100 pllons of water. Do not use more than
 TA quarts of this product per acre.

 DO  NOT APPLY TO AVOCADO WITHIN 21
 DAYS  OF HARVEST.

 WOCADO—To  control banded cucumber beetles,
 grasshoppers, citrus root weevils, red-banded Ihrips,
 avocado lace bugs, pyriform scales, webbing worms,
 Mossom anomala, little fire ants, greenhouse thrips
 and tortridds, use X pint in 100 pllons of water. To
             DO  NOT  APPLY  TO  THE  FRUITS  LISTED
                     WITHIN 14 DAYS OF HARVEST.
             MflES— For control of,  European sawflies,  San
             lose, Forbes or scurfy scales, mealybugs, European
             red and  two-spotted mites, bagworms, Japanese
             beetles, shot-hole borers, orange tortra and apple
             lace bugs, dilute tt pint in 100 gallons of water and
             spray to cover foliage thoroughly. For codling moths,
             use % pint in 100 pllons of water, 3 to 4 appli-
             cations, 10 to 14 days apart, starting 10 to 14 days
             after petal fall; for second and third broods, spray 1
             to 3 times at 10 to 14 day intervals. For fruit tree
             leaf rollers, use Vi pint per 100 pllons of water at
             petal nil and for red-banded leaf rollers, apply tt
             pint per 100 pllons of water at petal fall and at
             first, fifth and sixth cover spray. For plum curculio,
             apply at H pint per 100 pllons of water at petal fall
             and 1 or 2 additional times each 7 to 10 days apart
             For grasshoppers, use V pint in 100 pllons. For the
             following insects. H pint per 100 pllons of water is
             adequate: bud moths: dover, Pacific. Willamette or
             Schoenii mites; flea weevils; rosy, mxrty and green
             apple aphids; leafhoppers; leaf miners; and  red
             bugs. Certain insects, such as two-spotted Willamette
             mites, may require repeat treatments at 7 to 10 day
             intervals  during  the summer  months. Parathion
             sprays may injure the foliage and fruit of Mclntosh
             apples and related varieties, such as Cortland, Ken-
             dan, Macoun, Melba, ate, and Golden Delicious or
 Fruit Insects confd.
15
Fruit Insects cont'd.
17
                                                   225

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                                  Table  31.   (Continued)
  Fruit hotels confd
 18
                                                            Fnut Insects court
                                                           20
  Jonathan. Consult the State Apkuttunl Extension
  Service or Experiment Station for advice on posa-
  biity of mjory and safening the spay by uio| acti-
  vated carbon. Do not use more than IK gaBons of
  this product per acre.
  AfBJCOTS—To control  aphids. mites,  bod moths.
  peach tree borers, Japanese beetles and leaf rollers,
  use <  pint per 100 (aflons of water.  Control of
  coding moths,  lesser  peach tree borers,  grass
  happen, and tortrii requires K to % pint per 100
  gaBons. To control Oriental fruit moths, ose K to %
  pint per 100 pOons of water at shock spit, 10 to 12
  days later and if needed 6 and 3 weeks before har-
  vest For peach tree  borers and lesser peach tree
  borers, apply 2 or 3 sprays to trunk from {round to
  scaffold tabs toned with moth emergence. Use *
  pint»100 gallons of water for control of Panderms
  moths. Avoid injury to bees by delaying spray tiB
  after fuflbleonx to not use more than 3K quarts of
  this product per acre.
  BUJEKMJES-f or thrips, maggots, curcafio and
 Up  borers, use K pint in 100 gallons of water. For
 lecaoium vales, use 1 pint per 100 gallons of water.
 Use before froft sets or after harvest. Use from 100
 to 300 gaOons of diluted spray per  acre, but do not
 apply more than I1/, pints of this product to one
 acre of blueberries at any application.
                rWCHB AND NECTMUIES (teas other than Caf-
                fareia)—For control of green peach aphids, use X
                pint in 100 gallons of water. For peach tree borers,
                leaf rollers, mites, catfacug insects, tarnished plant
                hues, shot-hole borers, peach bark beetles,  states
                and bod moths, on K pint per 100 gallons of water.
                and repeat if re-infestation occurs. For Oriental fruit
                moths, see under apricots. For plum cnrcuBo, oseK
                pint per 100 gaflons of water. In the South, treat at
                petal faB, 10 days later and  repeat at 7 to 10 day
                intervals up to 3 weeks before harvest In the North.
                treat 3 to 4 tunes, 7 to 10 days apart, beginning at
                shuck-off. For lesser peach tree and American pturn
                borers and grasshoppers, use V to 1  pint per 100
                gallons. For peach tree borers and lesser peach tree
                borers, apply 2 or 3 sprays to trunk from ground to
                scaffold tabs timed with moth emergence. Do not
                apply more than 4 quarts of this material per acre at
                any appfcation, and do not use more than 5 quarts
                per acre per year.

               KKHES  AND NECnmiES  (CaHoruiaJ-Use as
               shown for other areas except do not appty within 21
               days of harvest Do not apply more than once after
               bloom. Do not apply more than 2% quarts of this
               product per acre at any application, and do not use
               more than 5 quarts per acre between January 1 and
               harvest
 CHHWES-For aphids and mites, mix % pint in 100
 gaflons of water. For sawffies, use X to K pint in 100
 (aflons of water. Use % pint per  100 gallons for
 thrips,  cherry  fnutwwuis, pear slags, Pandemu
 moths, bud moths,  cankerworms, rose  chafers, San
 Jose scale crawlers, fruit ffies and tortrii. For fruit
 tree leaf rollers, use K pint per 100 gallons of water
 at petal fall or shuck spit; for plum curcuio,  use
 V, port per 100 gallons of water, 2 or 3 appOcatJons,
 8 to 10 days apart beginning at petal fafl or shuck
 spit for Oriental fruit  moths,  use K pint  in  100
 gallons of water at shock spSt and 10 to 12  days
 later. For Japanese beetles, use K to 1  pint per 100
 gaOons. Do not  use more than 2V» quarts of this
 product per acre.

 (BATES—For mites, aphids, mealybugs and berry
 moths,  use H pint per  100 gaHons of water. For
 leaf roBers, Japanese  beetles and leaf  folders, use
 K pint  per 100  gallons  of water. For false chinch
 bugs, use 1 pint in 100 gaOons of water per acre
 fay ground equipment  or in 10 gallons of water by
 aircraft For eonsperse stink bugs,  use IK quarts
 per  acre. For grape leafhoppers, use  IK to 2K
 quarts per tat  for  Mack vine weevils, use 2K
 quarts per acre. Do not use more than IK quarts
 of this product per acre after the fruit is the size of
 buckshot Use 300 to 500 gallons of water per acre
 depending on age of vineyard and stage of plant
growth.
                          control  of leaf miners, aphids, leaf
              roflers, grasshoppers, states, mealybugs and certain
              mites, use the dosage  described for those insects
              on  apples. For pear psyfla,  use % pint  per 100
              gallons of water. For pear Mister mites, pear sJugs,
              green fruitworro and plant bugs, use K pint per 100
              gatons of water. For  coding moths, use K pint in
              100 gallons of water in 2 to 4 cover sprays, begin-
              ning with the first cover. For phim  curcuio, apply
              K pint in 100 gattons of water at petal fafl and 10
              days later. Some injury may occur on Bosc pears,
              under some conditions. Do not use  more than 3K
              quarts of tab product per acre.
              PUJMS AND nUNES-Appry K to % pint per 100
              gaBoos of water for control of these insects: pear
              thrips. flower thrips, mites, aphids, tearnoppen. leaf
              rollers, peach  tree borers,  shot-hole borers, bod
              moths, tortrii, mealy plum  Gee and scales. Apply
              scale treatment when crawlers emerge. For plum
              curcuio nuke 3  to  4 applications, begMoing  at
              petal f* at rate of K pint • 100 gaBoos ef water.
              For coding moths, use K to 1 pint per 100 gaBons
              of water  at petal fad and  a  summer ippfcafiM
              tamed with moth emergence. For peach twig borers.
              use 1 pint per 100 gaBons of water. Do not use more
              thai 4 quarts ef this  product per acre.
Fruit Insects eanf d.
19
                                                          Fruit Insects cunTd.
                                                         a
                                              226

-------
                               Table  31.   (Continued)
fa* hatch CMM
             •To control Aovtf thrift, cncfcfd,
tabeehs. red spio* mites. aplmfeLrrB tap.
bjomoppen. wMtdSts and tot rates, at H to 1
pmt • 100 to ISO picas if water per acre. To
             OMM korcn and strawberry led
     , m * pmt m 100 to 150 ptas of water
per ten. As a Mar veatmeot do not  use awn
IBM If, pints of Ifeis product per acre. To control
     i srmpkjtois, use 5 worts • 40 poom of
    r per acre as a prtpbot Mi treatment
00 NOT APPLY TO THE FRUITS LISTED
BELOW WITHIN 7 DAYS OF HARVEST.
               control of crickets and mealy
tan o» M pmt per 100 ptas of '
apply 300 ptas of spray ptr acre.
 00 NOT USE PARATHION ON OLIVES AFTER
 AUGUST 1.
 OUKS-for Mack, oleander aid partttoria safes.
 m 1 pM • n ptas iptmedwi frade summer
 •i umaiinn. or 1 plot itM-medwn pade sow-
                                                  Vtptaotehseds
             VEGETABLES
 DO NOT APPLY WITHIN 21 DAYS OF HARVEST
 ON THE FOLLOWING CROPS UNLESS OTHER-
 WISE SPECIFIED.
 COOT—To control ipotdv mites, celery worms
 aid tarnished  plant tap, use 1 pot per acre. To
 control leaf UMTS. •Metes and leafboppers. me
 lKpmtsperacre.tatdoMiise wUm 30 dap
 ofkanest
       -To caofrol peen peach aphidi aid aHalb
          11 pint per acre.
 IfrroCE (Uat ami 8mb>-For aphids. i
          mstar, cabbap kwoers. uwported cab-
           banded cucumber beetles and Lypv
 tap, ne H to 1 pmt per acre. To control six-spotted
 leafhoppers, cse * pmt per acre. For harlequin tap
 and feptabte wee*, use 1 pmt per acre. At the fc
 pmt rat*, harvest can be made  wram 14 days of
 •or tmallin oi m 100 pBoas of trater. post-bloom.
      -To control leaf miners and spider mites, use
 H to 1 pmt per acre. For aphids and stink tap. use
 1 pmt per acre.
 SMSS CHAW-To control apbds and  serpentine
 leaf miners, «st 1 pmt per acre

 DO NOT APPLY WITHIN 15 DAYS OF HARVEST
 ON THE FOLLOWING CROPS UNLESS OTHER-
 WISE  SPECIFIED
                NUTS
DO NOT APPLY AFTER HULLS OR HUSKS
BEGIN TO OPEN.  DO NOT FEED TREATED
HULLS OR HUSKS TO LIVESTOCK.
UMOKDS-To eorinl frwt tree leaf roBers. M
catorpOan «nd ptocfc Mf bom. ne 1 pM per
100 ptas of water. As a  dormant spray for par
htm and SM Jose scaks. gse 1 plot mth 3 p*«
darmant Ml emrisioi or 2M pBon dormait e«wl-
sivt oi m 100 fillORS of «ater. Do Ml ne more
tiM 3 •jwrts of ttis predict ptr lot

RUOnS-For appte mahrbap. fittert tphids. bod
•o*s Md spider mites, axe H pmt per 100 pHon
of vKr.  Do Ml use more IBM 3 Marts of ttis
predict per acre.

•fCMS-For control of apMs. ne * to « pint in
100 ptas of mttr. To control antes, pecan Mt
casebtarers aid peoa leaf casebeartrs. sst * pmt
m 100 ptas of wter To control Mack and »eflo»
pocan apbids. fal mttaorms and hri| firalen. •»
1 ijart per 100 ptas of  water. Do Mt me more
ton SK warts of tte pradKt per acre.

MUOTS-To control tphids. tecamim scales and
•afewt bust fSes. ne H pmt • 100 ptoos of water.
Do Mt «se more than » paws of tkis pnxtoet
per acre.

Nwftoacts                             »
KMS—For control of bean leaf beetles awl tmo-
spotted miles, use H pint per acre. Use H to * pmt
per acre to control tkrips aid fema pod borers. To
control stnk tap. plant tap. Uenoa bean beetles.
leaf rofcrs. leaf OHNTS. leifhopoers. apbids. red
spider mites and armyworms op to tttrd mstar. use
1 pmt per acre.
BEETS—To control flea beetles and leaf miners, ne
'A pmt per acre. For apbjtfs. bister beetles aid
•ebworau. «s* I pmt per acre. If (reeas are ned
for food, do not tat •*•• 21 dap of hanest
HJUEYED POS-To control aphids. leaf Men.
beta leaf roflers and stink bop. us* 1 pint per acre
CMMIS-To control leaf men. ne K to * pmt
per acre. To control teifhoppers. ise t pmt per
acre. Use 1 pmt ptr acre to control apbids. «cp>
tabk weenb. stak bup and petrobia mites. To tm-
tret rust DT manots (first brood), mii 1  pmt wrt*
100 ptorts per acre tat dribble into rarrow at
pbwtmf time. To control rust By mafpts (second
brood), use 1 pmt per acre as a Map spray. Do
Mt feed tops.
CUCUttBaS—f or squash vine borers, apbids. cn-
om«er beetles, leaf mmers. picUeworms, mites aid
thrips. ose K to 1 pmt per acre. For squash tap.
stmk tap. flea beetles and (eafnoppers. use I pint
per am. Do not apply prior to «WM{-
                                                 ftfftabte msects confd
                                           227

-------
                              Table  31.   (Continued)
  VepbMe loseds cooTd.
  EGOUKT-To control ttrips, leaf OMen, bister
  beetles, aod flea beetles, KM % to * pint per acre.
  To control Colorado potato beetles, OK * pM per
  acre. To total spider Mites art lace bop,  ne
  Xto 1 pint per aae. To caotrol aphids, •Mefies
  tod sM bop, ose 1 port per acre.
  ttWJC-To control  onion thrips, ose M port  per
  acre. To cootrol leaf OMen and pesroba onto*, ose
  1 port per acrt-
  MKMS—To control onion tbrips, tse  H port per
  acre. To coolrol OHM Mtjot fies, ose « pM per
  acre. To  coolrol apoids, sbok bop,  leaf i
  aod petrobia •ices, ose  1 plot per acre. To coon*
  Iran •heat oofes. ose  W piots per acre.
  rOTOS-To control ftrips, ose 7/16 to M pM per
  acre. To  coolrol aphids, leaf mam aod mntera
  potato flea beetles, ose  1 pint per acre.
  MNSHES-To  control apkids, false chinch bop
  aod barteoM bop, ne tt to 1 port per acre. To

  ose 1 port per acre.
  SnMC8-To control aphids. leaf OMen. anoy-
  MHOS op to third iostar,  cabbafe topers, veptaMe
  •eetfc, harieojM bop,  seed con onffots, crowo
  OHBB aod tejlBoppers. BK 1 pM per acre.
                                                      Yepteble oMuft cooT d.
                                                                To coolrol apUds,
  boron, ose Via 1 port per acre.
  fffllBBPt Mf rtl
  M aphids, teofooMn,
                                           optafJMov
              pen, ose Ipiot per acre. Oofal aod rtoter crops, do
              oot ose MUM 15 days of honest

              par acre.  To cooirot oonHOjnos, HoPJioppon aod
              psyMs, ose % port per acre. For aphids, bjnf onncn,
              •hrtefies, anoyvonos op to third outer, (rasshop-

              sank  bop, loopen and pbot bop. ose 1 port
              par acre.
                                              false
               bop aod hatlaoaio bop, ose % to 1 plot per acre.
               To coolrol cabbap loopen, ose 1 pM per acre. M
               ^MBS tWC BSM lOf lOOOf  W M* tpfty VRHI Zl
               dojs of harvest

               DO NOT APPLY WITHIN 7 DAYS OF HARVEST
               ON THE FOLLOWING CROPS UNLESS OTHER-
               WISE SPECIFIED.
                         -To coolrol arochote
                                                      ose 1 ooart per acre.
SQMSH-To control cocamber beetles,  aphids,
sint bop. OMloooomii. pieUenoron, cioiBioicit-
•omo, serpeofioe  leaf OMen aod sooasb vioe
borers, ose % to 1 pnt per acre. To cootrol sqoasn
bop, flea beetles  and leafluppen,  ose 1 pint
per acre.
SHEET POnroES-To control aphids, spider OHles.
leaflMppm and sfiok bvp, use 1 port per acre. To
cootrol serpeofioe leaf OMen and owraiouJofy
leaf OMen, «e 1 to 1H pints per acre.

DO NOT APPLY WITHIN 12 DAYS OF HARVEST
ON THE FOLLOWING CROPS.
SHEET COW-To control com etrwonw feednf
m the bod, fal araqrwonn. aphids aod s*fBes, ose
K pM per acre. To  control sap beetles and spider
antes, ne 1 pint per acre. To control duoch bop,
ose Hi pints per acre.

DO NOT APPLY WITHIN 10 DAYS OF HARVEST
ON THE FOLLOWING CROPS UNLESS OTHER-
WISE SPECIFIED
fBB-To control aphids, pea neenb, spider nates,
sfok bop, ttrips, anajwoms up to third Mar,
ctabioc otMnos. leaf OMen, alfaKa loopen aod
cotey loopen. ose 1 pint per acre. If noes art to be
osed for forap, do oot harvest lor 15 days after
             CWMOE  AND C0l£ CUPS (bVoeeol,
             Sproots, Cio«inu)-To cootrol aphids, thrips. db-

             cobbap loopen and anayworou op to third iostar,
             ose % to 1 pint per acre. To control harleqwi bop,
             ^^^^•iVJ^  .	^-«-  j;_«.--_  - ^--	   	j m	
             fff^BDIC  ofBCVIo^ CMoWMf  ConVOim  JM 1KI
             beetles, ose 1 pint per acre. Rates above fc port
             short not be appfod to eobbop closer than 10
             •tys MO  ioWcsl,
             WHUBW-To coolrol aphids, ose 1 pM per acre.
             inTUtt (HeadMa control aphids, cabbap loop-

             Mcocs, LypD oTitp. vcftponiis oWo oWywofws i^
             to third iostar, ose % to 1 pint per acre. To control
             six-spotted teaftoppen. ose * pint per  acre. For
             harleqM bop, vegetable wevos  and leaf miners,
             ose 1 port per acre. To control prdeo stjojphytaos,
             broadcast IV pMoos per acre pot prior to ptonfiof
             aod flMroefUy incorporate into upper 6 to 9 aches
             of sol.
             PJEUNB-for sojoash vine borers, leaf onocn aod
             Use chjoch bop, ose W pint per acre. For aphids,
             IftflMMtffi^ cvcvMbCf fcfftfCTt Bicklcvonw Md
             oiiles, ose  H to 1 pM per acre. To cootrol thrips,
             sojoash bop and stink bop, ose 1 port per acre.
             •VTMAttS-To cootrol  apoids, cattop loopen
             oiid cfcobnn cotMflos, «e 1 port per acre
VepbMehBects cooTd.
27
VeptaMe Inseds coofd
                                           228

-------
                            Table  31.   (Continued)
                                                 Field aod fanfi ***** <***
DO NOT APPLY WITHIN 5 DAYS OF HARVEST
ON THE  FOLLOWING CROP
              cart* apMs. bfister beetles,
Colorado poMo beetles. leaf *«om win. ptart
           piffed, flpfvpf, vcfRiMc wccns 9M
               H to 1 pi* per acre  Fir anoy
         to ffcird  Mstar, csboofe toppers, aod
        obMraB, KM * p*rt per acre For leaf
boppers. sfc* top aod flea keete. me I port
per acre.
           SOTKMS—To cortol wswonv*. ose M pfeet per
           acre  T* ca«tre4  whet kea* oterpdbrj,  pea
           ehMtmauB, too-spotted Milei wd itat b«fj  OK
           1 pat per acre Te cartel can tanranm aod fall
           arafiOTu. nt 1 to 1'A pMs per acre T* a*
           tool «Me jn*» aid iwniwoB. broadtail 1 fatal
           per acre jMt prior to ptofltaf a
           corporate Mo «pper 4 to 6 wckes of toil.
   HELD AND FORAGE CROPS

00 NOTAPPLYWTTHIN 15 DAYS OF HARVEST,
CUTTING OR FORAGE USE ON THE FOLLOW
INC CROPS.
           9NM KETS-for aMatta (oopen.
           •wm ip to ttird wt*. feafhoppen. kfester beetles.
           te keetki, leaf Men, Lrpn bop. stMi tup. Mb
           •mn^dMnf orl»orm art piirtoppen, at I
           9* per acre  For tabe celerj leaf Sen. at ft p«b
           per acre  Far beet crom borera, ne 1% pate per
           acre,  (mead appicattoa owr Ike nw dwwf iced
           i«C itace To cwrtrol wtate puks Md mre«n«
           broaden! 1 fata per acre pot prior to ptMtMf
           aod thorMfMr iKoporate «t« opper 4 to i •<*«
           ofioiL
                     -To CMtrol »>re«omv «e 2 ojaarb
              Utol2iKiiha«d«theopet terra* at fioM of
       , OMB, VETCH MB Ctt8-f or Meet
d**tr apkidi tkree-eenered aMatfa keppe
catoraflers, aod iptffiekop. ose % port per tot For
opbids.  aNato wetii lame. aod ad* weevils.
anyvonoa op to tttrd onto, clover leaf VJMVOS,
           DO NOT APPLYWTTHIN12 DAYS OF HARVEST.
           CUTTING OR FORAGE USE ON THE FOLLOW
           ING  CROPS.
«rfcA MM tortriod Motta, OK H to 1 piat per acre
For aWfa teed dttkids eootrol M atfoKa from tor
Mod, OK M to 1 port per acre. Cattoraia aod Menda
nfrfriton tmt »e ow of On natenal to oot owre
fbjo) v pvt per aort. For doMr bead geeMh. spider

dooer Meiii. ao4 free*  AM beeflei «te 1 piat
pw acre. Far bed anayvonojs aaid corn earvoran
ose 1 to IV5 oMi per acre. Do oot spray hymu
djriag Moo* period to avoid iopjry to beaey bees.
KMm— To cootrol  
-------
                           Table  31.   (Continued)
HeM and Forage Insects cont'd.
34
COTTON—To  control  aphids,  mites, cotton  leaf
worms, cotton fleahoppers, garden webworms and
thrips, use Vi pint per acre. For some spider mites,
use 'A to Vt pint per acre. For cabbage loopers, use
% to 1 pint per acre. For boll weevils and stink bugs,
ose 1  to  l'/i pints per acre. For salt-marsh cater-
pillar*, use 1  to 2 pints per acre. For bollworms,
cotton  leaf  perforators, Lygus bugs, false chinch
bugs, serpentine leaf miners and  southern garden
leafhoppers, use 1 quart per acre. Use enough water
for complete coverage. Make first application when
insects appear and  repeat at 7 day intervals if re-
quired. If desired, this formulation may be combined
with other insecticides in a complete cotton spray
program.

TOBACCO—For control of aphids,  stink bugs and
tobacco suckflies, use H pint per acre. Do not apply
within 5 days of priming or 15 days of cutting. Avoid
plant juices coming in contact with the skin or other
parts  of  the body  of those who  are engaged in
cutting the crop.


          MISCELLANEOUS
CABBAGE—For application to cabbage grown for
seed only to control cabbage seed pod weevils, use 1
quart per acre.

CHRISTMAS TREES—To control aphids and mites,
use W pint per 100 gallons of water.
                                                      Soil Insects cont'd.
            CORN ROOTWORMS-To control on:
                 Peanuts
            Apply 2 to 2% qt. per acre as a row soil treatment
            at planting or pegging  time, work lightly into soil.
            GARDEN SYMPHLAN—To control on:
            Bern         Lettuce        Sugar Beets
            Corn           Potatoes       Tomatoes
            Apply 5 qt per acre to soil surface before planting
            time and thoroughly work into upper 6 to 9 inches.
            CUTWORMS—To control on:
                    Cora                 Cmnben
            Broadcast 3 qt to  1 gal. per acre before planting
             and thoroughly work into upper 1 to 3 inches.
            WHfTE GRUBS—To control on:
            Con          Soybeans       Sugar Beets
             Broadcast 3 qt to 1 gal.  per acre before planting
             and thoroughly work into upper 4 to 6 inches.
             NOTE:  Consult the State Agricultural  Extension
             Service or Experiment Station  concerning specific
             usage, dosages and methods of application.
                            896.09-000.13/53

                  (EPA Reg.  No.  524-132)

                         MONSANTO COMPANY
                        AGRICULTURAL DIVISION
                         ST.  LOUIS.  MO.  63166
 HOPS—For control of hop aphids, use 1 to !'/»
 pints  per  acre.  For spider mites,  use  !'/>  pints
 per acre. Do not apply within 15 days of harvest

 SAFFFOWER —To control aphids, Lygus  bugs and
 grasshoppers,  use 1 pint per acre. Do not use  para-
 thion after (lowering.
              SOIL  INSECTS
 WIREWORMS—To control on:
                                Rutabagas
                                Soybeans
                                Sugar Beets
                                Sugarcane
                                Sweet Corn
                                Sweet Potatoes
                                Tomatoes
                                Turnips
                                Watermelon
 Broadcast 3 qt to 1 gal. per acre on soil before plant-
 ing and thoroughly work into upper 4 to 9 inches.
 HIREWORMS-To control on:
       Tobacco
 Broadcast 2 qt. per acre on soil at least 3 weeks
 before planting and work into top 6 to 9 inches.
 WIREWORMS-To control on:
     Potatoes
 Broadcast 1 to IVt gal. per acre on soil before plant-
 ing and thoroughly work  into upper 4 to 9 inches.
Beans
Beets
Broccoli
Brussels Sprouts
Cabbage
Cantaloupe
Carrots
Cauliflower
Celery
Com
Endive
Egg Plant
Escarole
Kale
Lettuce
Onions
Peas
Peppers
 Soil Insects
                                           35
                                          230

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        Table  32-  REGISTERED USES OF PARATHION  EMULSIFIABLE LIQUID

               (4  LB ACTIVE INGREDIENT PER GALLON)  - CROPS AND

             OTHER USES,  PESTS, DOSAGE RATES AND  USE LIMITATIONS-
                           STOP -  READ  THE LABEL
See Side  Panels
   for Antidote  &
      Precautions
                 Keep Out of
                 Reach of
                 Children
ORGANOPHOSPHORUS INSECTICIDE
Active Ingredient — Parathion:
  O,O-diethyl O-p-nitrophenyl phosphoro-
  thioate 		 46.4%
  Xylene-range solvent	— 47.7%
Inert Ingredients	_	~  5.9%
  Contains 4 Ib. Parathlon/Gal.	
COMBUSTIBLE — Keep away from heat & open
flame.
Read Label Folder for additional  use precautions,
directions for use, recommendations and container
disposal.           E.P.A. Reg. No. 476-603-AA
                     EMULSIFIABLE
                              LIQUID

NOT FOR  HOME  USE
See side panels for poison precautions, symptoms.
first aid treatment, information  for physician and
posting treated areas.

NOTICE: Stauffer Chemical Company makes no war-
ranties, express or implied, Including the warranties
of merchantability and/or fitness for any particular
purpose concerning this material, except those which
are contained on Stauffer's label.     ARC 710325
                                  Made in USA By
              STAUFFER  CHEMICAL  COMPANY
                        NEW YORK, NY IOOI7
  aj  Sample label of Stauffer  Chemical Company.
      EPA Registration No. 476-603-AA.
                                       231

-------
                    Table 32.  (Continued)
     DANCER - POISON - PRECAUTIONS
Don
SWAUOW
              ^"
POISONOUS IF SWALLOWED
Even in small amounts!
DON'! 10DCN      11
             I
POISONOUS BY SKIN CONTACT
Poisonous if touched by hands or spilled or
splashed on skin, in eyes or on clothes (liquid
goes through clothes).
                    POISONOUS IF BREATHED
                    Poisonous if vapor or mists from sprays are
                    breathed. Vapors are not visible. Never work
                    with parathion or  in parathion treated areas
                    without protective clothing and equipment.
     POISONOUS TO FISH & WILDLIFE: Toxic to fish and wildlife. Birds and other wildlife in
     treated areas may be killed. Shrimp and crab may be killed at application rates recom-
     mended on this label. Do not apply where these are important resources. Keep out of any
     body of water. Do not apply when weather conditions favor drift from treated areas. Do
     not apply where run-off is likely to occur.
                            232

-------
Table 32.  (Continued)
WORK SAFETY  RULES
USE ONLY WHEN WEARING THE FOLLOWING PRO-
TECTIVE CLOTHING 4ND EQUIPMENT: (1) Wear water-
proof pants, coat, hat, rubber boots or rubber overshoes.
(2) Wear safety goggles. (3) Wear mask or respirator ap-
proved by the U. S. Bureau of Mines for parathion protec-
tion. (A) Wear heavy duty natural rubber gloves.

Keep unprotected persons and children away from treat-
ed area or where there is danger of drift.

Do not  rub eyes or mouth with hands. Do not smoke.
Before removing gloves, wash them with soap and water.
If you feel sick in any way STOP work and get help right
away. Tell foreman or have someone call  him. Call a
physician, clinic or hospital immediately.

ALWAYS wash hands, face and arms with soap and wa-
ter before smoking, eating or drinking.

AFTER  WORK,  lake  off all work clothes  and shoes.
Shower, using soap and water. Wear only clean clothes
when leaving job.  DO  NOT wear  contaminated work
clothing.

All protective clothing and equipment should be washed
with  soap and water after each use. Respirators should
be cleaned and filter replaced according to instructions
Included with respirator.

      POISON  SIGNS  (Symptoms)

Parathion is  a very dangerous  poison. It  rapidly enters
the body on contact with  all skin  surfaces, eyes  and
by contact with skin  through wet clothes. Worker who
shows any of the following poisoning signs must receive
Immediate medical treatment or he may die.

Slgni and Symptoms  of Poisoning Are: Headache, nau-
sea,  vomiting, cramps,  blurred vision, pin-point pupils,
tightness of chest, labored breathing, weakness, nervous-
ness, sweating, watering of eyes, drooling  or frothing
of mouth and nose, muscle spasms and coma.

POSTING TREATED AREA:   Consult state regulatory
agencies for posting regulations and requirements.
                         FIRST  AID  TREATMENT
                    Speed is essential to slop absorption of poison.ll
                    It possible, one person should make telephone
                    calls while another begins treatment.
                Call a physician, clinic or hospital immediately In  all
                cases of suspected poisoning. Explain victim exposed
                to parathion; describe his  condition. Until medical help
                is available take following steps.
                IF BREATHING HAS STOPPED, start artificial respiration
                immediately  and continue until physician sees victim.
                IF SWALLOWED and victim is awake (conscious) make
                him vomit quickly.  First,  give soapy water  or strong
                salty water  to  drink then stroke back  of throat with
                finger to make victim vomit. Repeat by giving more water
                and make vomit again until vomit fluid is clear.  Never
                give anything by mouth to an unconscious person. Have
                victim lie down and keep  quiet
                IN CASE OF SKIN CONTACT, immediately remove wet
                clothing and shoes and flush skin with water for at least
                15 minutes.
                EYE CONTACT:  If splashed in eyes,  immediately flush
                eyes with water for at least 15 minutes.
                      After  first aid is given  and physician can
                      not come take victim to clinic or Hospital.
                      Bring "Label Folder."  Give  to physician.

                NOTE TO PHYSICIAN
                ANTIDOTE—Administer atropine sulfale  in large doses,
                2.0 to 4.0  mg. intravenously or intramuscularly as soon
                as cyanosis  is overcome. Repeat at  5  to 10 minute inter-
                vals until signs of atropinization appear. 2-PAM chloride
                is. also antidotal and may be administered in conjunction
                with atropine. Do not give morphine or tranqulllzer*.
                Parathion  Is a strong chollnesterase Inhibitor affecting
                the central  and peripheral nervous system,  producing
                cardiac  and  respiratory depression.
                At first signs of pulmonary edema, the patient should be
                given supplemental oxygen and treated symptomatically.
                Continued absorption of the poison may occur and fatal
                relapses have been reported after  initial improvement.
                Very close supervision is indicated  for ut least 48 to
                72  hours.
          233

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                                      Table  32.  (Continued)
                               LABEL FOLDER

                                    CONTAINS

                  ALL DIRECTIONS FOR USE
 Organophosphorus Insecticide
 Emulsifiable Liquid
POISON
DANGER
  NOT FOR
HOME USE
  Before Using Read All Precautions
          and Directions for Use

 E.P.A. Reg. No. 476-603-AA                ARC-710426


     RESEALABLE BAG
     I    Pull flaps apart to open.
     V   Press along ridge to close.
                IMPORTANT


SEE  REVERSE  SIDE  OF  FOLDER

CONTAINS  SAFETY  LABELING

             INFORMATION


• Active Ingredient Statement

o Primary Statements of Hazard, Precaution-
   ary Instructions.

• Fish and Wildlife Precautions

• Work Safety Rules

o Poison Symptoms

• First Aid Treatment

• Note to Physician
 STAUFFER  CHEMICAL COMPANY
              NEW YORK, N. Y. 10017
                                            234
USE  PRECAUTIONS
READ ALL PRECAUTIONS AND DIRECTIONS BEFORE
USING. Use only for crops and claims recommended.
This  product is toxic to fish and wild life. Keep out of
lakes, streams, and  ponds. Birds and other wildlife in
treated  areas may be killed. Do not apply when weather
conditions favor drift from areas treated.
This  product is highly  toxic to bees exposed to direct
treatment or residues on crops. Protective information
may be obtained from your Cooperative Agricultural Ex-
tension Service.
In order that pesticidal residues on food and forage crops
will not exceed tolerances established by the Federal
Food and Drug Administration, use only at recommended
rates and intervals, and do not apply closer to harvest
than  specified.  Do not  apply or allow to drift to areas
occupied by unprotected humans or beneficial animals
or onto adjoining food, fiber or pasture crops. The grow-
er is responsible for residues on his crops as well as
for damages caused by drift from his property to that of
others.
Consult state agricultural extension service or state agri-
cultural  experiment stations for additional information.
as the timing,  number, and rate of applications needed
will vary with local conditions.

CONTAINER  DISPOSAL
Destroy Empty Container — Never Re-Use
Completely empty contents and bury unused chemical
18 inches deep in an isolated  location away from water
supplies.
Glass Container: Break container and bury 18 inches
deep.
Metal Containers: 1 gal. drum: Pour 1 qt. of water into
empty drum. Add 1 tablespoon of household detergent.
Rotate drum carefully until all inner surfaces  are wet
Bury rinse solution  18" deep. Punch holes ir. top and
bottom  of container, crush and bury. 5 gal. drum: Pour
2 qt of water into empty drum. Slowly add Vi cup caustic
soda  (lye) and 2 tablespoons of household detergent. Fol-
low the same rinsing, destruction and burial procedures
given for 1 gal. drum. 55 gal. drum:  Follow same proce-
dures as for 5-gal. drum except use 5 gal. of water, 2 Ib,
of lye and cup of detergent
CAUTION: Do not get rinse solution on hands, in eyes
or on clothing. Wear protective clothing and equipment
In case of contact wash immediately with soap and water.

DIRECTIONS  FOR USE
Application can  be made by aircraft or ground  power
equipment by trained personnel only using approved pro-
tective equipment. Do  not apply with hand equipment
Pour  specified  amount  of this product into nearly filled
spray tank. Add balance of water to fill tank. Keep agita-
tor running during filling and spraying operations. If mix-
ture does not mix readily, but tends to separate as an oily
layer, do not use as  injury to plants may result. Do not
combine with wettable powders unless previous use of
the mixture has proven physically compatible and safe
to plants. Always thorough^ emulsify this product with
at least half  of total  water  before adding  wettable
powder.
SUGGESTED WATER  RATES FOR  AIRCRAFT  AND
GROUND APPLICATION. (The actual rate required to pro-
vide thorough, uniform coverage varies with plant growth
at time of application.  Except as specified for certain
uses, the following rates are therefore intended to cover
a broad range of conditions.)

Crop                             Aircraft
Vegetable and  Field  Crops ...... ------- -  1-20
Orchard, Grapes -------------------------- ...... — - 5-25
Orchard Crops  (See exceptions below) ._.
Citrus              - ____ ....... __________ —
Grapes '""""'
                                                         Ground
                                                          5- 125
                                                                                            500-3000
                                                                                            100- 200
                 Maximum permissible rate per acre, expressed as Para-
                 thion 4-E, is given in parenthesis ( ), after each crop
                 claim.

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                                  Table  32.    (Continued)
RECOMMENDATIONS


         FRUIT  AND NUT  CROPS

(Also Read Directions for Use)

Unless otherwise specified, rates are given in terms of
Parathion 4-E per 100 gal. of water for thorough coverage
application. Unless otherwise specified, apply at the first
sign of infestation  and repeat at 7-10 day intervals as
needed to maintain control, but observe use limitations
given for specific crops.


APPLES
Codling moth, European red  mite, fruit tree leaf roller,
mealybug, orange tortrix, plum curculio, red-banded leaf
roller (1st, 2nd and 3rd broods), two-spotted mite. Use
Vfept

Aphids (rosy apple, green apple), bud moth, Pacific mite,
red bug, Schoenii mite and Willamette mite. Use %  pt

CAUTION: Injury to fruit and foliage may result from use
of this material on Mclntosh and related varieties. Do not
apply within 14 days of harvest. (1V4 gal.)
APRICOTS
Codling moth, Oriental fruit moth, tortrix. Use Vi-lV% pt.
Bud moth, fruit tree leaf roller, spider mites, aphids. Use
% pt.  Do not apply until danger of bee poisoning has
passed. Do not apply within  14 days  of harvest.  (7-1/5
pt)


CHERRIES
Black cherry aphid, eye-spotted bud moth, lesser apple
worm,  mites, shot-note borer, Western cherry fruit fly.
Use n pt For fruit fly control, begin applications at fly
emergence and repeat at  7 day intervals. Do not apply
within 14 days of harvest (4-1/5 pt.)


CITRUS
CALIF. RECOMMENDATIONS: Citrus thrips. Use 3 pt in
10-20 gal. water when applied by  aircraft; 100-200 gal.
water by ground equipment. Apply at petal fall; repeat in
late summer and early fall  to protect new growth and pre-
vent fruit scarring. Citrus scales. Parathion 4-E is recom-
mended for control of California Citrus Scales. The prod-
uct may be used in conventional high-pressure  ground
sprayers or boom sprayers and airblast equipment when
the latter are capable of providing thorough coverage.
Black Scale—Use 1 pt. Make a full coverage spray during
Aug.-Nov. California Red and Yellow scales—Use IV* pt
alone or with 1V4-1% gal. of a light or light medium oil
emulsion in a full coverage spray at recommended times.

Citricola and Cottony-Cushiony scales—Use 3  pt. Apply
100-400 gal. spray per acre. Or use  Vt pt in a full cover-
age spray during Aug.-Nov.; increase dose to V* pt. during
Feb.-Mar. and to Vi pt. during May and June applications.
Purple  scale—Use 1 pt or % pt. with lVi-1% gal.  of a
light or light medium oil emulsion in a full coverage spray
n recommended times. Max. Rate/ Acre and Date Limita-
tion: (1 gal. up to 14 days of harvest; 2Vz gal. up to 30
days of harvest).
GRAPES

Calif. Recommendations:  Mealybug. Use 2 pt plus 2
gal. dormant oil emulsion. Apply during dormant period.
Spray vines after pruning but before budding.  Refer to
Extension bulletin  for  complete spray  program. Leaf
folder. Use 2 pt Mites. Use Vi pt Repeat applications
at 5-7 day intervals. Max, Rate/Acre and Date Limitation:
3 pt. up to 14 days of harvest; 5 pt. if applied before fruit
is the size of buckshot or after harvest
NECTARINES, PEACHES
Catfacing insects, Oriental fruit moth, peach twig borer,
thrips (on Nectarines only), San Jose scale. Use 1 pt. Cot-
tony peach scale, fruit tree leaf roller, green peach aphid,
spider  mites. Use  % pt. Limitations: Areas other than
Calif.:  Full coverage spray for control of scale  insects.
Do not apply within 14 days of harvest. Do not apply more
than 4 qt. per acre per application or more than 5 qt. per
acre per year. Calif.:  Do not apply within 21  days of har-
vest. Do  not apply more than  once after bloom. Do not
apply more than 2Vx qt. per acre per application  or more
than 5 qt. per acre between Jan. 1st and harvest.


PEARS
Codling moth, mealybug, pear  blister mite, woolly aphid.
Use Vi pt. in pre-blossom spray. Pear psylla, spider mites.
Use % pt. Make  either  pre-blossom or post-blossom
sprays for the pear psylla.  Under some conditions, injury
may occur  on Bosc pears in the Northeast. Do not apply
within  14 days of harvest. (7-1/5 pt)


PLUMS,  PRUNES
Aphids, bud moth,  leafhopper, leaf  roller,  mealy plum
louse, spider mites, tortrix. Use Vi pt. Peach twig borer.
Use 1 pt. Do not apply within 14 days of harvest. (1 gal.)


OLIVE
Scales (parlatoria, oleander, black). Use 1 pt. with regu-
lar oil spray during June or July. Do not apply after Aug.
1. (2V4 gal.)

STRAWBERRIES
Southeast  Region:  Field  crickets,  flea  beetles, flower
thrips. leaf rollers, pameras. Use Vi-\ pt Spider mites.
Use % pt. Do not apply within 14 days of harvest. (2 pt.)
Other Areas: Aphids. Use 1-1-3/5 pt Do not apply within
14 days  of harvest.  (1-3/5 pt.) Post-harvest control  of
root weevil. Use  2 pt. (2 pt)

WALNUT
Aphids, red spider. Use Vz pt. Repeat at 7-10 days for
red spider. Codling moth. Use % gal. Do not apply after
husks open. (2Vi gal.)
   VEGETABLE  AND  FIELD  CROPS

    (ALSO READ DIRECTIONS FOR USE)

Unless otherwise indicated, dosages  are given in pints
of Parathion 4-E  per acre in sufficient water to provide
thorough coverage.  Begin applications when insects first
appear and repeat  at  7-10  day intervals as needed to
maintain control, but observe  use  limitations given for
specific crops.


ALFALFA
Alfalfa Weevil
Calif.: Apply Vi-%  pt. per acre in  15-20 gal. water per
acre. Make application  when  75% of terminals show
feeding damage.  Make no application within 15 days of
cutting or  forage use. (% pt.)
Areas Other Than Calif.: Apply V4-1  pt. per acre as speci-
fied and limited above. (1-3/5  pt)

ALFALFA SEED CROPS
Alfalfa chalcid, alfalfa weevil larvae, aphids, armyworms,
blister beetles, lygus stinkbugs. Areas Other Than Calif.:
Use Vi-1-3/5 pt.;  Calif., use %-l pt Use in early morning
or late evening to avoid injury to pollinators. Birds and
other wildlife  in  treated areas may be harmed.  Do not
apply within 15 days of harvest. Do not use Parathion if
field to be cut for hay. (Areas Other Than Calif., 1-3/5 pt;
Calif., 1 pt.)
                                                  235

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                              Table  32.  (Continued)
 ALFALFA, CLOVER,  VETCH
 Aphids (including yellow clover aphid), armyworms. blis-
 ter beetles, grasshoppers. Apply Vz-V* pt. per acre. Make
 no application within 15 days of cutting or forage use.
 (Calif.—% pt. for all crops)
 (Areas Other Than Calif.—1-3/5 pt. for alfalfa and vetch;
 3 pt. for clover)

 ARTICHOKE
 Aphids. plume moth. Use 2 pt. Do not apply  within 7
 days of harvest. (2 pt.)

 BEANS (Dry and Green)
 Aphids, armyworms, leafhopper, leaf miner,  leaf roller,
 Mexican bean beetle, spider mites, stinkbugs,  whitefly.
 Use 1-1-3/5 pt. (1 pt.—7  days of harvest; 1-3/5 pt—15
 days.)

 BEETS
 Aphids, armyworms, blister beetle, flea beetle, leafhop-
 per, leaf miner, webworm. Use 1-1-3/5 pt. Do not apply
 within 15 days of harvest;  21 days if treated tops are to
 be used for food or feed. (1-3/5 pt.)

 CABBAGE, CAULIFLOWER,  BROCCOLI,
 BRUSSELS SPROUTS, KALE, MUSTARD,
 TURNIPS
 Aphids,  armyworms,  cabbage  looper, flea beetle,  dia-
 mond-back  moth  larvae,  imported cabbageworm,  ser-
 pentine leaf miner, thrips. Use 1 pt.
 Rates and Use Limitations: Broccoli, Brussels sprouts,
 cauliflower: 1 pt.—7 days; 3 pt.—21 days. Cabbage, kale,
 mustard, turnips: Vz pt—7 days; 1 pt—10 days (cabbage
 only 3 pt.—21 days).

 CARROTS
 Aphids. Use 3,i>-%  pt.  per 100 gal. Apply 300 gal.  per
 acre. Do not  use  treated carrot tops for food or feed.
 Do not apply within 15 days of harvest. (2 pt.)

 CELERY
 Aphids, celeryworms, celery leaf tier, leafhoppers, spider
 mites. Use  1-2 pt (1  pt—21 days  of harvest; 2 pt.—30
 days.)

 CORN
 Armyworms,  corn  rootworm adults (make full  coverage
 applications  to foliage  when adult beetles become  nu-
 merous and repeat as necessary). Use  Vi pt. European
 corn  borer.  Use 1-2 pt Do not apply within  12 days of
 picking or cutting for forage. (2 pt.)

 COTTON
 Aphids, armyworms (up  to 3rd instar), brown cotton leaf-
 hopper,  false chinch  bug, salt-marsh  caterpillar,  ser-
 pentine  leaf miner, southern garden  leafhopper,  stink
 bugs, spider mites, thrips. Use 1 pt.
 Bollworm, cotton leaf perforator, fleahopper, lygus bugs,
tobacco budworm. Use  2 pt.
 Limitations. For all uses  listed  above do  not exceed
2% pt per  acre. Do not  apply within 5 days  of hand-
 picking. Workers entering treated fields within  24 hours
of application should wear protective clothing.

CUCUMBER, SQUASH, MELONS
Aphids cucumber beetle, cutworms, darkling ground bee-
tle (lea beetle, leafhopper, leaf miner, melonworm, pic-
kle'worm,  serpentine  leaf  miner,  squash bug,  spider
mites, petrobia mite, thrips. Use 1 pt. Do not apply unless
plants are  dry nor before plants start  to vine. Do  not
apply within 15 days of harvest on cucumber and squash;
7 days of harvest on melons. (1 pt.)

EGGPLANT
Aphids. leaf miner, red spider mites, thrips. Use %-Vz
pt Do not apply within 15 days of harvest (1-3/5 pt)
LETTUCE, ENDIVE
Aphids, leafhoppers. Use 1 pt. Do riot apply within 7
days of harvest on head lettuce; 21 days on endive, leaf
and bibb lettuce. (1 pt.)

MOSQUITO  CONTROL
In Rice Fields and  Irrigated Pastures: Apply 3.2 fluid
ounces in 5-20 gal.  water  by aircraft or in 25-100 gal.
water by ground equipment. Do  not apply to water drain-
age areas where run-off or flooding will contaminate
ponds, lakes or streams. Keep out of tidal marshes and
estuaries.  Do not apply  with 1 day of harvest of rice;
7 days of pasturing or harvest of grass pasture. (3.2 fluid
ounces)

OKRA
Aphids, flea beetle, leaf miner, stinkbugs. Use Va-1 pt
Do not apply within 21 days of harvest (1-3/5 pt.)

ONIONS
Thrips: Apply 1-1-3/5 pt. and repeat at weekly intervals
as necessary for control. Do not apply within 15 days of
harvest. (1-3/5  pt)

PEAS
Aphids, armyworms, climbing cutworms, pea weevil, ser-
pentine leaf miner, thrips: Use 1 pt Do not apply within
10 days of harvest. (1 pt)

PEPPERS
Aphids, pepper maggot, flea beetle, serpentine leaf min-
er, thrips. Use 1-1-3/5 pt. Do not apply within 15 days of
harvest. (1-3/5 pt)

POTATOES
Aphids, armyworms,  Colorado potato beetle, flea beetle,
green  stinkbug, leafhopper, leaf  miner, spider mites.
Use 1-2 pt Do not apply within 5  days of harvest (2 pt)

RICE
(CALIF. ONLY)—Rice leaf miner, tadpole shrimp. Use 1/5
pt. in  5-10 gal. water. Apply by aircraft at the first sign
of infestation after planting. Restrict spill from rice fields
for 2  days following application.  Do not apply within 1
day of harvest.  Caution: Do not  use within 14 days of ap-
plication of  Stam  F.34 or Rogue. Injury may result. Do
not spray over canals or laterals. (1/5 pt)

SMALL GRAINS
(BARLEY, OATS, WHEAT)—Aphids,  armyworms. grass-
hoppers, greenbug. Use Vz-% pt  Do not apply within 15
days of harvest. (3 pt)

SORGHUM
False chinch bug, grasshoppers. Use V4-%  pt Corn ear-
worm, sorghum webworm.  Use  Vi-1 pt Sorghum midge.
Use 1  pt. and make  2 applications 3-5 days apart when
approximately 90% of the heads have emerged from the
boot.  Aphids, mites. Use 2 pt.  Do not apply  within 12
days of harvest or cutting for forage. (2 pt.)

SPINACH
Aphids, leaf miner. Apply Vz-1 pt  Do not apply within 14
days of harvest. (1 pt)

SUGAR  BEETS
Aphids, armyworms, blister beetle, flea beetle, leafhop-
per, leaf miner, mites, webworm.  Use 1-1-3/5 pt Do not
apply  within 15 days of  harvest  (1-3/5 pt)

TOMATOES
Aphids, flea  beetle,  leafhopper,  serpentine leaf miner,
spider mites, stinkbugs, tomato pinworm. Use 1V4-2 pt
Do not apply within 10 days of harvest. (2 pt)
                                                236

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                      One quart of parathion 4 Ib/gal  formulation contains
                      1 Ib of active ingredient;  1 pt contains 0.5 Ib of
                      active ingredient.  Thus, recommendations given in
                      terms of quarts are equivalent to pounds of active
                      ingredient;  recommendations given in terms of pints
                      convert into active ingredient by multiplication with
                      the factor 0.5.

     Parathion is also available to users in the form of emulsifiable liquids
containing 2, 6 and 8 Ib of active ingredient per gallon; furthermore, in the
form flowable liquids containing 4 or 8 Ib of active ingredient per gallon;
as wettable powders containing 15 or 25% of active ingredient, and as dusts,
granulars and pressurized sprays of various active ingredient concentrations.
In addition, a number of dry and liquid formulations combining parathion
with other insecticides and/or fungicides are registered.

     For most registered uses of parathion, the rate of active ingredient
recommended per acre or per volume of spray for a given use is the same,
regardless of the type of formulation in which the product is applied.


State Regulations - In many of the states that currently regulate the use of
pesticides, parathion is subject to use restrictions.  For instance,  in
California, parathion is one of 42 pesticides that have been  designated as
"injurious or restricted materials."  The use of  pesticides in this category
is subject to special restrictions under regulations administered by the
State Department of Agriculture.  A permit from the County Agricultural
Commissioner must be obtained for the use of parathion.  The  product may not
be applied in any location where damage, illness  or injury appears likely to
result through direct application, drift, or residue, to persons, other crops,
or animals (including honeybees)  other than the  pest(s) which the application
is intended to destroy.

     Before parathion is applied,  the person responsible for  the application
must give warning to all persons known to be on the property  to be treated.
After any formulation containing parathion has been applied at a rate
greater than 1 Ib of active ingredient per acre,  the treated  property must
be posted for 2 weeks to provide adequate warning to persons  at the point or
points of normal entry.  The warning notice must be readable  at a distance
of 25 ft.

     Under this code, it is unlawful to sell or deliver parathion-containing
pesticide products to any person who is required to have a permit, unless
the person or his agent signs a statement that he has a valid permit to use
the product.
                                    237

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 Similar restrictions on the use of parathion are in effect in a number
 of other states, although California appears to have the most specific  and
 best enforced regulations.  In some states, parathion can be used only  by
 licensed applicators.

      Details of the pesticide use and application laws on a state-by-state
 basis have been summarized by EPA, Office of Pesticides Programs, in a
 publication entitled "guide for Analyzing Pesticide Legislation/Digest  of
 State Pesticide Use and Application Laws."  This pesticide law digest is
 being kept up to date by addition and replacement pages issued to holders
 from time to time.

      In addition to restrictions on the use of parathion Imposed by
 state statutes and regulations, many states augment parathion product label
 requirements with specific recommended uses designed to accommodate local or
 regional requirements.  These are usually issued Jointly by the State
 Agricultural Experiment Station and Extension Service in cooperation with
 the U.S. Department of Agriculture.  The state insecticide use recommenda-
 tions are issued or revised annually.


 Production and Domestic Supply of Parathion in the United States

 Volume of Production - The United States Tariff Commission,  named
 three basic producers of parathion in the United States:   Monsanto Co.,
 Stauffer Chemical Co., and Kerr-McGee Chemical CorpJL'  Parathion is
 currently produced by Monsanto.

      In that report,  the production and sales volumes of parathion are  not
 reported individually.  Parathion is included in a group consisting of
 seven other specified, and additional unspecified cyclic phosphorothioates
 and phosphorodithioates.   The reported production volume for this entire
 group in 1972 was 44,385,000 Ib of active ingredients.   Through a process
 of  careful analysis of the use patterns of all organophosphate insecticides
 in  this group,  supported  by information from trade sources,  Midwest
 developed estimates on the volume of production of all major products in
 the group.   The estimated volume of production of parathion in 1972 is  14
 million pounds of active  ingredient.
I/U.S. Tariff Commission, Synthetic Organic Chemicals, U.S. Production and
      Sales, 1972, TC Publication 681 (1973).
                                    238

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     According to Midwest Research Institute/RvR Consultants, 1974-
 about  10 million pounds of this total were produced by Monsanto Company,
 the balance by Stauffer and Kerr-McGee.

 Imports - Imports of pesticides that are classified as "benzenoid chemicals"
 (including parathion) are reported by the U.S. Tariff Commission in its
 annual report on "Imports of Benzenoid Chemicals and Products" (TC 1973, and
 covers the calendar year 1972.  According to this source, there were no imports
 of parathion into the United States in 1972.

Exports - Pesticide exports are reported by the Bureau of the Census in
its annual report FT 410.   Technical (unformulated) parathion and methyl
parathion are included in this report in Schedule B, Section 512.0652.
Formulations of parathion (and of all other cyclic and acyclic organic
phosphate insecticides) are included in Schedule B, Section 599.2035,
entitled "Organic phosphate containing pesticidal preparations, except
household and industrial and except fly sprays and aerosols."

     Total exports of organic phosphate insecticides in these two categories
for 1972 are as follows:

     Section 512.0652 (parathion and methyl parathion technical) -
       16,533,940 Ib

     Section 599.2035 (organic phosphate containing formulations) -
       15,898,884 Ib

     To derive the 1972 export volume of parathion from these totals,
 Midwest Research Institute made a thorough analysis of these two pesticide
 export categories by unit dollar values and by countries of destination.
 This Information was then matched against the crop protection problems
 and the pesticide trading patterns of the countries of destination.
 Additional information was obtained from confidential trade sources.
 Estimates from this data place the 1972 export volume of parathion at 4
 million pounds of active ingredient.
 I/  Midwest Research Institute/RvR Consultants, "Production, Distribution,
       Use, and Environmental Impact Potential of Selected Pesticides,"
       (draft), Council on Environmental Quality, Contract No. EQC-311
       (15 March 1974).
                                      239

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Domestic  Supply - The information presented in the preceding three sections
estimates the domestic supply of parathion in the United States in 1972.
Subtracting  exports from total production, Midwest Research Institute concludes
tnat about 10 million pounds of active ingredient were used domestically  in
1972.                               ~~	

     It  is not possible at  this  time  to make  comparable estimates  for 1973,
because  the  U.S. Tariff Commission  report on  the production and sales of
pesticides and related products  in  1973 will  not become available  until the
late fall of 1974.

Formulations - Parathion is available to  users in the United States  in a
variety  of different  formulations,  and through a considerable number of
suppliers.  The basic domestic producers  of technical parathion sell a
large  share,  or all of their production,  as technical to f emulator-customers
who prepare  and sell different formulations of parathion under a variety
of different labels and brand names to end users,  either directly, or
through  wholesalers ., and/or retailers.

     Frear (1972)—' lists almost 100  products containing parathion,  offered
by many  different suppliers, as  follows:

                                                      Products

     Aerosols (concentration not given)                  2

     Sprays  (emulsifiable liquids containing
       2,  4, 6, or 8 Ib of  AI per gallon;
       flowable liquids containing  4  or 8 Ib
       of AI per gallon; wettable powders
       containing 15 or 25% of AI)                       60

     Dusts (varying concentrations)                      22

     Granulars (varying concentrations)                   4

     Manufacturing concentrates                           4
I/  Frear, D. E. H., Pesticide Handbook Entoma, 24th Edition,  College
      Science Publishers, State College, Pennsylvania  (1972).
                                 240

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        In addition to  these  formulations containing parathion only, the product
   is also offered in combination formulations with other insecticides and/or
   fungicides,  in dry and  liquid formulations.  Among these, an emulsifiable
   liquid containing 6  Ib  of  parathion and 3 Ib of methyl parathion per gallon
   has recently gained  in  popularity and use volume.

   Use Patterns of Parathion  in the United States

   General - Essentially all of the quantities of parathion used in the
   United States were in agriculture.  There were no significant uses of
   parathion by industrial, commercial or institutional pesticide users;
   by Federal, state, county, local, or other governmental agencies; or
   by home and garden users.
        Surveys on the  use of pesticides by farmers were conducted by the U.S.
   Department of  Agriculture  in 1964 (Agricultural Economic Report No. 131,
   published in January 1968), in 1966 (Agricultural Economic Report No. 179,
   published in April 1970),  and 1971  (Agricultural Economic Report No. 252,
   in press).   Data on  the uses of parathion in 1972 were obtained by RvR
   Consultants.

        The following farm uses of parathion were reported:


   Year      Source                   Farm Use

   1964      USDA           6,426,000 Ib of active ingredient

   1966      USDA           8,425,000 Ib of active ingredient

   1971      USDA           9,481,000 Ib of active ingredient

   1972      RvR           10,000,000 Ib of active ingredient

     These figures indicate an upward trend in the quantities of parathion
used by farmers during the 8-year period covered by the surveys.

     As outlined earlier in this subsection, parathion has a very broad
spectrum of effectiveness and is registered and recommended in the United
States for use on a large number of fruit, nut, vegetable and field crops.
                                    241

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 Table 33  presents  a  breakdown  of  the  estimated uses of parathion in the
 United States  in 1972,  by  regions and major crops.  The following informa-
 tion sources were  used  in  arriving at these estimates:

      1.   The three USDA surveys of pesticide uses by farmers mentioned above.

      2.   The annual  USDA publication  "Pesticide Review" (Agricultural
          Stabilization  and Conservation  Service).

      3.   Results of  a survey of the Federal/State Cooperative Extension
          Services  in all 50 states and in Puerto Rico conducted by RvR
          Consultants in 1973.

      4.   Analyses  of state pesticide  use recommendations.

      5.   Local and regional estimates on pesticide use volumes obtained from
          State Research and Extension personnel in personal communications.

      6.   Pesticide use  reports from the  States of Arizona, California, Illinois,
          Indiana,  Michigan,  Minnesota, and Wisconsin.

      7.   Data  on pesticide uses supplied by the EPA Community Pesticide Studies
          Projects  in Arizona,  Hawaii, Idaho, Mississippi, South Carolina,
          Texas,  and  Utah.

      8.   Estimates and  information obtained from basic producers of parathion
          and other pesticides, and from  pesticide trade sources.

      9.   Pesticide use  surveys conducted recently by Wallaces' Farmer, Des
          Moines, Iowa;  Prairie Farmer, Chicago, Illinois; and Wisconsin
          Agriculturist,  Madison,  Wisconsin.

    10.   "Agricultural  Statistics," an annual publication of the U.S. Depart-
          ment  of Agriculture.

     Data from all of these  numerous  and diverse sources were carefully
analyzed, correlated cross-checked and cross-validated.  The resulting
estimates as summarized  in Table  33 are  believed to be the best and most
up-to-date information  on  the  use patterns of parathion in the United States
currently available.


                                     242

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                      Table  33.  ESTIMATED USES OF PARATHION ON THE U.S. BY
                                   REGIONS AND MAJOR CROPS (1972)
Region

Other
grains ,
Cotton Corn sorghum
Crop
Citrus
Vegetables fruits

Other
fruits,
nuts

All
other
Tobacco crops

Totals,
all
uses
Northeast^
Southeast-'
East North Central^/
West North Central^
East South Central—^
West South Central!'
Northwest^'
Southwest"-'
Totals, 50 States
  500
 Negl.
 Negl.
  700
  600

  500

2,300
Negl,
 150
 200
 200
  50
Negl,
Negl.
Negl.

 600
                                         Thousands of Pounds of Active Ingredient
Negl.
Negl.
Negl.
1,050
Negl.
1,100
   50
   50
           100
           100
           100
           Negl.
            50
           400
           200
           650
2,250    1,600
—
100
--
•**»
Negl.
««•
200
300
250
100
100
Negl
100
300
150
650
1,650
Negl.
 300
Negl.
 50
150
100
 50
100
100
100
350
  400
1,400
  500
1,300
1,000
2,500
  500
2,400
                                         300 1,000     10,000
Source:  RvR estimates, see text.
a/  New England States, New York, New Jersey, Pennsylvania
b/  Maryland, Delaware, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida
cV  Ohio, Indiana, Illinois, Michigan, Wisconsin

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 Parathion Uae Patterna by Regions - Analyzing parathlon uses on a geo-
 graphical basis,  It Is Interesting to note  that  about  one-half of the
 total  quantity of the product used in the U.S. In  1972 (alaost 5 million
 pounds AI) was used In the Southwestern United States,  i.e., in the West
 South  Central and Southwest regions (Table  33).  In these areas, about
 1.2  million pounds of parathion AI were used on  grain  crops other than
 corn (primarily sorghum); 1.1 million pounds AI  on cotton; and about 1
 million pounds AI each on vegetable and fruit crops.

     The Southeastern states used an estimated 1.4 million pounds of
 parathion AI.  Of this total, about 500,000 Ib was for cotton, another
 300,000 Ib for tobacco.   The balance was used on vegetables, citrus
 and  other fruits, and other crops.

     An estimated 1.3 million pounds of parathion  AI were used in the
 West North Central region, primarily on sorghum  and other small grains.

     In the East  South Central region, a combined  total of about 1
 million pounds of parathion AI was used on  all crops,  primarily on
 cotton (700,000 Ib).

     The Northeastern,  East North Central and Northwestern regions of
 the  country eaehiused an estimated 500,000  Ib of parathion AI or less.
 There  were no single  major uses on individual crops in these areas.

 Parathion Use Patterns by Crops - Analyzing the  parathion use pattern by
 crops,  it appears that cotton Is the single largest "consuming" crop.
 Parathion is registered and recommended against  19 different insect and
 mite pests on cotton.

     The use of parathion on grain crops, especially sorghum, has increased
 substantially during  the last few years and is almost  equal to the volume used
 used on cotton in 1972.   Increased use Is largely  due  to infestation of the
 greenbug,  Schlzaphis  graminum.   This insect, recorded  in the United States
 as early as  1882,  for  the first time severely damaged  sorghum crops in a
 number  of states  in 1968.   This development has  been attributed to a new bio-
 type of  the  species,  known as "Biotype C".^'  The  primary use of parathion
 to control the greenbug  was on sorghum in Southern Nebraska, and in Kansas,
Oklahoma  and Texas.
I/  See Eight, S. C., R. D. Eikenbary, R. J. Miller, and K. J.  Starks,
      "The Greenbug and Lysiphelbus testaceipes."  Environmental Entomology
      1(2):205-209 (1972).
                                    244

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     Paratblon uses cm vegetable and fruit crops each amounted to about
1.6 Billion pounds of active ingredient in 1972, with the largest amounts
of product used in the Southwestern states.

     Approximately 600,000 Ib of parathion AI were used on corn in 1972;
and about 300,000 Ib AI each on citrus fruits and on tobacco.   The remain-
ing 1 million pounds of AI went on a large variety of other crops, with
no single one outstanding.

Parathion Uses in California - The State keeps detailed records
of pesticide uses by crops and commodities.  They are published quarterly
and summarized annually.  Table 34 summarized the uses of parathion In
California by major crops for the 4-year period 1970 to 1973.   The total
volume of parathion used during this period varied relatively little, but
there were considerable changes in the uses on different crops from year
to year.  For instance, the use of parathion on citrus fruits increased
from 137,000 Ib AI in 1970 to 234,000 Ib in 1973.  Parathion uses on stone-
fruits  (peaches, nectarines, apricots) varied from a low of 83,000 Ib AI
in 1971 to a high of 227,000 Ib in 1970.

     Tables 35 and 36 present parathion uses In California by crop, number
of applications, pounds of active ingredient, and number of acres treated,
for 1972 and 1973, the two most recent years for which such data are avail-
able.  In both years, parathion was used In California on close to 100
different crops.

     Incongruities and inconsistencies were found In statistics on parathion
uses on California crops.

     A  significant amount, 90,000 Ib, of parathion AI was reportedly used
on cotton in California in 1972, and 107,000 Ib  in 1973.  However, the
University of California Extension  Service recommends  the use  of  parathion
on cotton only against the false chinch bug, described as an  "occasional
Insect  problem," but not against major California cotton pests such as the
cotton bollworm, the pink bollworm, the cotton  leafperforatort  Lygus bugs,
or mites.

     The California Department of Agriculture reported using 186,000 Ib of
parathion AI on citrus crops  (oranges, lemons,  grapefruit) in  1971 (Table 34)
However, the U.S. Department of Agriculture in  Quantities of Pesticides
Used by Farmers in 1971 (Agricultural Economic Report No. 252;  in press)
reports only 68,000 Ib of parathion used on citrus fruits in  the  entire U.S.
During  the 1971 to 1972 season, California produced about 22%  of  all citrus
fruits  in the United States.*'
I/  U.S. Department of Agriculture, Agricultural  Statistics.  1973.  Table 314,
      p. 219.
                                     245

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          Table 34.* PARATHION USES IN CALIFORNIA BY MAJOR CROPS
                        AND OTHER USES (1970-1973)
Crop

Citrus (oranges, lemons,
grapefruit)
Peaches, nectarines,
apricots
Plums, prunes
Almonds
Olives
Tomatoes
Lettuce
Beans
Artichokes
Cotton
Sugar beets
Alfalfa
Rice
Vector control
All other uses
Totals, all uses

1973
Thousands
234
157
58
82S/
9
90
90
30
49
107
71
23
29
26
159
1,214^
Year
1972
of Pounds
185
170
68
87
30
55
80
29
60
90
48
24
37
20
114
1,097

1971
of Active
186
83
22
11
11
85
180
23
49
108
71
32
37
29
142
1,069

1970
Ingredient
137
227
83
70
9
62
84
28
19
87
54
42
20
51
199
1,172
California Department of Agriculture, Pesticide use reports for
  1970, 1971, 1972 and 1973.
a/  Quantity used on almonds in 1973 and 1973 total reduced by 738,000 Ib
      to adjust for apparent system error; see text.
                                      246

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Table 35.  USE OF PARATHION IN CALIFORNIA IN 1972,  BY CROPS,
        APPLICATIONS, QUANTITIES, AND ACRES TREATED
Commodity
Alfalfa
Alfalfa fur seed
Almond
Anise
Apple
Apricot
Artichoke
Asparagus
Avocado
Barley
Beans, dry edible
Beans, green or forage
Beans for seed
Beet
Berries
Boysenberry
Broccoli
Brussels Sprouts
Cabbage
Cantaloupe
Carrot
Cattle lot
Cauliflower
Celery
Cherries/sweet
Chinese cabbage
Citrus
Clover for seed
Corn/field
Corn/sweet
Cotton
County or city parks
Cucumber or pickle
Deciduous fruit crops
Eggplant
Endive
Escarole
Fallow (open ground)
Flowers
Foliage
Garlic
Grapefruit
Grape
Grasses/field
Honeydew melon
Leek
Lemon
Lettuce/head
Lettuce/leaf
Applications
762
26
946
2
23
330
1,197
3
5
31
579
42
1
145
1
1
117
190
205
12
92
1
219
1,005
25
4
176
1
45
45
1,579

13
1
1
2
1
18
37
2
41
42
131
1
1
2
120
5,259
111
Pounds
22,750.66
891.86
87,125.86
4.35
474.32
20,234.65
59,719.59
187.50
230.00
1,100.42
27,374.78
1.122.56
15.24
4,087.71
6.49
5.00
1,480.44
3,865.67
1,762.94
575.12
2,452,39
2.28
2,268.67
8,375.55
767.10
3.50
13,721.63
148.47
4,949.58
9,970.83
90,188.18
79.21
714.06
200.00
0.06
6.00
3.39
818.76
939.77
302.23
1,036.71
2,893.88
14,475.03
138.17
47.38
4.61
7,738.15
79,298.56
822.90
Acres
67,005.20
1,960.00
56,341.56
8.00
347.50
14,505.75
125,272.20
75.00
144.00
2,905.00
39,437.20
1,521.00
20.00
9,442.68
7.00
10.00
2,790.60
6,320.50
3,243.53
1,234.00
3,950.45
6.00
4,144.70
16,176.43
570.50
7.00
5,242.86
80.00
4,619.00
4,568.00
138,256.00

442.00
80.00
12.50
10.00
6.00
479.00
188.25
285.10
1,357.64
518.50
5,936.00
148.00
80.00
18.00
3,352.66
143,022.99
1,797.28
                            247

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                                Table 35.*  (Continued)
Commodity Application!
Melons
Nectarine
Monagricultural areas
Nuraery atock
Data
Okra
Olive
Onion/dry
Onlon/green/spr Ing/shallot
Orange
Orchard
Ornamental!
Ornamental bedding planta
Other agencies
Parsley
Paature/rangeland
Peach
Pear
Pea
Pepper /bell
Plun
Potato
Prune
Pumpkin
Radlah
Residential control
Rice
Safflower
School district
Sorghum
Spinach
Squash, summer
Squash, winter
Strawberry
Sugar beets
Tangelo
Tangerine
Tomatillo/husk tomato
Tomato
Turf
Turnip
University of California
Vector control
Walnut
Water areas
Watermelon
Wheat
Total
20
848
86
3
6
4
130
434
14
1,892
1
23
6

1
48
2,018
75
102
28
632
127
411
28
11

1,047
2

36
283
36
3
25
1,379
5
4
1
1,467
42
5


40
1
13
13
24,943
Pounds
882.34
34,638.86
1,215.85
65.30
303.09
24.59
30,120.72
10,505.22
383.23
160,377.37
15.36
72.61
13.92
66.99
0.03
764.00
115,217.86
10.358.27
379.61
315.15
25,781.16
6,413.46
42,035.64
910.93
84.98
0.49
37,089.58
14.15
10.39
6,414.95
4,136.89
713.84
36.02
248.27
48,317.65
968.74
174.68
2.40
54,824.06
4,657,58
49.75
50.38
19,502.16
2,304.36
166.37
653.56
406.00
1,097,091.02
Acres
1,658.00
16,818.24
12,870.00
62.00
230.00
38.00
2,753.73
16,689.57
590.00
52,854.95
58.00
161.50
20.00

12.00
8,118.50
63,054.65
4,440.60
638.00
672.63
11,580.05
9,218.23
23,587.33
1,351.00
149.00

160,493.20
54.00

1,884.50
8,280.60
1,240.00
110.00
438.00
107,933.88
67.00
291.00
4.00
85,433.63
5,365.14
71.00


1,472.50
200.00
1,158.00
1,043.00
1,271,111.01
'California Department of Agriculture, Pesticide Use Report  1972.
                                      248

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Tabla 36?  USE OF PA8ATHIOH  IK CALIFORMIA IV 1973, BY CROPS,
        APPLICATIONS,  QUANTITIES, AXD ACHES TREATED
Cownodity
Alfalfa
Alfalfa fur aaad
Almond
Anita
Appla
Apricot
Artichoke
Avocado
Barlay
Baana, dry adibla
Baant, graan or foraga
Baana for aaad
Baat
Barriaa
Broccoli
Bruaaala aprouta
Cabbaga
Cantaloupa
Carrot
Cauliflovar
Calary
Charriaa/avaat
Chinaaa cabbaga
Citrua
Cola cropa
Conifar
Corn/fiald
Corn/a waat
Cotton
County or city parka
Cucunbar or pickla
Daciduoua fruit cropa
Applicattona
593
141
753
2
17
257
1,260
5
41
731
3
1
428
1
113
104
186
1
68
134
923
16
13
79
4
1
42
23
1,866

10
1
Daciduoua ornanantal traaa 1
Fallow (opan ground)
Flowara
Poliaga
Carlic
Crain
Crapa fruit
Crapa
Lanon
L«teuca/laad
Uttuca/laaf
Malona
Muatard
Mactarina
Nonagricultural araaa
Muraary atock
Data
Olive
15
92
1
37
2
50
160
140
4,723
61
17
I
743
27
4
1
186
Pounda
17,438.41
5,676.99
820,076.97
10.50
356.13
20.545.64
49,345.86
290.00
3,541.15
25,977.89
83.14
45.90
16,050.15
4.14
1.844.81
1,730.76
2.061.55
8.88
1,266.47
1,705.68
8,338.25
1.169.79
36.41
12,609.15
13.26
0.08
10,929.58
894.18
107.117.83
87.79
397.02
15.74
10.50
16.900.93
300.29
0.64
1,642.56
174.67
3,017.74
14,683.10
24,787.06
89,729.12
272.47
517.60
4.95
23,236.60
297.42
167.33
66.63
8,863.74
Acraa
48.943.00
10,017.00
42,126.24
21,00
252.50
13,286.00
70.363.60
142.00
9.816.00
45,711.20
141.00
50.00
31,719.40
7.00
2,837.84
2,949.50
3,203.60
20.00
2,983.72
2.625.50
14.915.76
286.50
109.00
3,509.30
49.00
5.00
4.560.00
2,372.00
175,081.44

178.00
9.00
7.00
673.00
488.75
32.00
2,726.50
116.00
616.30
7,817.50
4,099.60
153,259.37
609.68
1,141.00
11.00
14.065.13
589.00
59.75
150.00
3,872.49
                              €49

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                       Table 36.* (Continued)
Commodity Applications
Onion/dry
Onlon/green/spring/shallot
Orange
Orchard
Ornamentals
Ornamental bedding plants
Other agencies
Pasture/rangeland
Peach
Pear
Pea
Pepper /bell
Pimento
Plum
Potato
Prune
Pumpkin
Radish
Residential control
Rice
Rutabaga
Safflower
Salsify fur .seed
School district
Soil (fumigation only)
Sorghum
Sorghum fur seed
Spinach
Squash/ summer
Squash, winter
Strawberry
Structural control
Sudangrass
Sugar beets
Sunflower seed
Sweet potato
Tangelo
Tangerine
Tomato
Turf
Turnip
University of California
Vectur Control
Walnut
Water Areas
Watermelon
Wheat
Total
401
11
2,206
1
3
3

15
1,904
64
202
37
1
588
76
421
10
8

1,453
1
16
1

5
62
1
187
17
1
36

3
1,779
3
67
2
1
1,514
71
2


72
1
5
30
25,361
Pounds
11,761.03
92.46
194,061.11
98.00
5.12
24.00
11,753.39
2,086.59
112,936.23
6,795.70
774.99
1,113.73
69.59
21,962.58
2,068.47
35,670.73
276.17
147.16
5.40
29,104.95
9.89
14,674.06
3.50
33.22
757.64
2,368.37
0.12
2,040.11
573.03
30.53
463.54
0.90
35.16
70,502.40
493.29
2,784.45
43.75
60.00
89,928.84
7,564.36
21.34
142.55
26,445.43
6,400.90
0.01
369.33
1,084.96
1,951,982.53
Acres
16,160.25
119.00
65,776.52
56.00
12.00
12.00

1,707.00
63,493.38
5,471.50
817.25
1,794.25
75.00
10,596.13
3,438.00
20,463.25
456.00
250.00

217,010.70
16.00
2,965.00
2.00

209.00
4,147.00
98.50
4,112.34
525.00
100.00
842.00

96.00
143,517.78
575.00
2,889.00
30.00
20.00
113,610.50
8,541.00
37.00


2,368.50
2.00
600.00
2,241.00
1,373,878.02
California Department of Agriculture,  Pesticide Use report  1973.
                               250

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     Regarding the California Department of Agriculture's reported
figure of 820,077 Ib, of parathion used on the State's almond crops
in 1973, available figures for the three proceeding years show that
parathion uses on almonds were considerably lower:  1970,  70,000 Ibs;
1971, 11,000 Ib; 1972, 87,000 Ib; (see Table 34).   Based  on an analysis
of past level of use and the number of acres treated in 1973, Midwest
Research Institute believes there to be an error in the reported 1973
figure for parathion use in California and has accordingly revised the
figure (See Table 34).*'

     At the present time, no other state in the union records or
publishes pesticide use data in comparable detail.   Limitations of time
and resources did not permit development of estimates on the uses of
parathion by crops and states beyond the detail provided  in Table 34.

Summary - In 1972, parathion was used in the United States on the following
major crops (listed in decreasing order of volume of use):  cotton, sorghum
and small grains; deciduous fruit and nut crops; vegetable crops, corn;
citrus fruits; tobacco; and numerous other crops,  each accounting for a
relatively small share of the total use.

     By geographic regions, the use pattern of parathion in 1972 was as
follows (regions listed in decreasing order of volume of use):  West South
Central (Oklahoma and Texas); Southwest (California, Arizona, Hawaii,
New Mexico, and Nevada); Southeast; West North Central states;East South
Central states; Northwest; Northeast.

     Slightly more than 10% of the total quantity of parathion used in the
U.S. in 1972 was in California, on almost 100 different crops.
I/  In a personal communication, the California Department of Agriculture
      agreed that the reported figure of 820,077 Ib was most likely erroneous.
      The agency did not account for the discrepancy.
                                    251

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                      PART  III. MINIECONOMIC REVIEW


                                CONTENTS



                                                                        Page

 Introduction 	   254


 Cotton	   256
   Efficacy Against  Pest  Infestation  	    256
   Cost  Effectiveness Of  Pest Control	   257
 Sorghum	   257


   Efficacy Against  Sorghum Midge Infestation  	   258
   Cost  Effectiveness of  Sorghum Midge Control  	    258
   Efficacy Against  Greenbug Infestation  	  259
   Cost  Effectiveness of  Greenbug Control  	 ...   261


 Wheat	262
  Efficacy Against Pest Infestation  	  262
  Cost Effectiveness of Pest Control	262
Peanuts	263

  Efficacy Against Pest Infestation 	  263
  Cost Effectiveness of Pest Control	263
Corn	264
  Efficacy Against Pest Infestation	264
  Cost Effectiveness of Pest Control	264
                                    252

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                         CONTENTS (Continued)
                                                                     Page
Potatoes	    265



  Efficacy Against Wireworm Infestation	   265
  Cost Effectiveness of Wireworm Control	265
  Potato Aphid Control 	  266
  Leafhopper Control 	  266

Lima Beans	266


Peas	267


Strawberries 	  267


References	269
                                    253

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      This  section contains  a general  assessment  of  the efficacy and cost
 effectiveness  of  parathion.   Data on  the  production of parathion in the
 United  States  as  well as  an analysis  of its  use  patterns at  the regional
 level and  by major crop are found in  Part II of  this report.

 Introduction

      The efficacy and cost  effectiveness  of  a specific pesticide should
 be measurable  in  terms of the increased yield or improved quality of a
 treated crop which would  result  in a  greater income or lower cost than
 would be achieved if  the  pesticide had not been  used.  Thus, one should
 be able to pick an isolated test plot of  a selected crop, treat it with
 a pesticide, and  compare  its yield with that of  a nearby untreated test
 plot.   The difference in  yield should be  the increase due to the use of
 the pesticide.  The increased income  (i.e.,  the  yield multiplied by the
 selling price  of  the  commodity)  less  the  additional cost (i.e., the pesti-
 cide, its  application and the harvesting  of  the  increased yield) is the
 economic benefit  due  to the use  of the pesticide.

      Unfortunately, this  method  has many  limitations.  The data derived is
 incomplete and should be  looked  on with caution.  Midwest Research Institute's
 review  of  the  literature  and EPA registration files revealed that experimental
 tests comparing crops treated with specific  pesticides to the  same crop without
 treatment  are  conducted by  many  of the state agricultural experimental stations.
 Only  a  few of  these however, have attempted  to measure increased yield and
 most  of this effort has been directed toward just a few crops  such as cotton,
 potatoes,  and  sorghum.  Most other crop tests measure the amount of reduction
 in pest levels which  cannot be directly related  to  yield.

      Even  the  test  plot yield data are marginally reliable,  since these
 tests are  conducted under actual field conditions that may never be
 duplicated  again  and  are  often not representative of actual  field use.
 Thus, yield is  affected by  rainfall,  fertilizer  use, severe weather con-
 ditions, soil  type, region  of the country, pesticide infestation levels
 and the rate,  frequency and  method of pesticide  application.

     Because of these factors, yield  tests at different locations and
 in different years  will show a wide variance ranging from a yield de-
 cline to significant  increases.   For  example, in a  year of heavy pest
 infestation, frequent pesticidal use  can  result  in  a high yield increase
because the crop  from the untreated test  plot is practically destroyed.
Conversely, in  a year of  light infestation,  the  yield increase will be
slight.
                                   254

-------
     Thus, the use of test plot yield data is at best qualitative and is
used for order-of-magnitude economic cost and benefit determination.

     The use of market price to estimate the value received by the pro-
ducer also has its limitations.  If the use of the pesticide increases
the yield of a crop and the national production is increased, then the
market price should decline.  According to J. C. Headley and J. N. Lewis
(1967),—  a 1% increase in quantity marketed has at times resulted in a
greater than 1% decrease in price.  Thus, the marginal revenue from the
increased yield would be a better measure of value received.

     A third limitation to the quantification of the economic costs and
benefits is the limited availability of data on the quantities of the
pesticide used by crop or pest, the acres treated, and the number of ap-
plications.  In most cases the amount of parathion used on each crop or
each pest is not available.

     As a result of these limitations an overall economic benefit by crop
or pest cannot be determined.  This review presents a range of the po-
tential economic benefits derived from the use of parathion for control
of a specific pest on a specific crop.  This economic benefit or loss is
measured in dollars per acre for the highest and lowest yield developed
from experimental tests conducted by the pesticide producers and the
state agricultural experimental stations.  The high and low yield in-
creases are multiplied by the price of the crop and reduced by the cost
of the parathion applied to generate the range of economic benefits in
dollars per acre*

     Efficacy and yield changes due to the use of parathion have been
reported on several crops and pests.  This report summarizes the results
of these tests which include the bollworm, boll weevil, and tobacco bud-
worm on cotton; the sorghum midge and greenbug on sorghum; the greenbug
on wheat; the southern corn rootworm on peanuts; the Pacific wireworm,
potato aphid and potato leafhoppers on potatoes; the European corn borer
and western corn rootworm on corn; the lygus lesperus on lima beans; the
tarnished plant bug on strawberries; and the pea aphid on peas.
I/  Headley, J. C., and J. N. Lewis, The Pesticide Problem;  An Economic
      Approach to Public Policy, Resources for the Future, Inc., pp. 39-40,
      (1967).
                                 255

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Cotton

     Parathion  is  registered  for a wide variety of cotton insects.  The
tobacco budworm, bollworm, boll weevil, aphids, fleahoppers, leaf hoppers,
cabbage loopers, spider mites, and thrips are major cotton pests treated
with parathion.  Application  rates vary from 0.25 to 1.0 Ib/acre, depend-
ing upon  the  type  of  insect.  The number of applications depends upon
the degree  of infestation.  Repeated  applications are recommended for the
bollworm, budworm,  and boll weevil until adequate control is achieved.

Efficacy Against Pest Infestation - Data is available on the efficacy of
parathion for control of  the  budworm, bollworm, and boll weevil— the three
major cotton  pests—'from tests conducted in Texas.

     Adkisson et al.  (1966)!/ compared a wide variety of insecticides
for control of  bollworm larvae near College Station, Texas in 1965.  The
use of parathion resulted in  a 70% kill after 48 hr when applied at 0.5
Ib/acre.

     Adkisson et al.  (1967)^.' conducted similar tests in 1966 and reported
an 85% kill of  bollworm larvae 48 hr  after parathion was applied at 0.5
Ib/acre.  Farathion was also  less effective against the budworm with an
83% kill at 0.75 Ib/acre  after 48 hr  compared to a 97% kill for 0.75
Ib/acre of  methyl parathion.  Against adult boll weevils, 0.25 Ib/acre of
parathion resulted  in a 97% kill after 48 hr compared to 100% for methyl
parathion at  the same rate.

     Wolfenbarger  (1973)^7 found that tobacco budworms from a susceptible
strain were 2.45 times more resistant to parathion than to methyl para-
thion during  tests  conducted  in Brownsville, Texas in 1970.
I/  Adkisson, Perry L., and S. J. Nemec, "Comparative Effectiveness of
      Certain Insecticides for Killing Bollworms and Tobacco Budworms,"
      Publication B-1048, Texas Agr. Exp. Sta.  (1966).
2j  Adkisson, Perry L., and S. J. Nemec, "Insecticides for Controlling
      the Bollworm, Tobacco Budworm, and Boll Weevil," MP-837, Texas Agr.
      Exp. Sta. (1967).
3f  Wolfenbarger, D. A., "Tobacco Budworm:  Cross Resistance to Insecti-
      cides in Resistant Strains and in a Susceptible Strain," J. Econ.
      Entomol., 66:292-294 (1973).
                                    256

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Cost Effectiveness of Pest Control - Information was found on .only one
test relating yield changes to parathion usage.  Host (1974)-' summarized
tests conducted between 1956 and 1973 at Stoneville, Mississippi.  The re-
sults of one test in 1956 showed a 253 Ib/acre gain over an untreated check
when nine applications of parathion at 0.5 Ib/acre were made.

     The 1972 price received by farmers for cotton was 14.0c/lb for lint.
Additional income from cottonseed of 4.2c/lb and government price supports
of 12.5c/lb brought the total income to 40.7c/lb (Agricultural Statistics,
1973).-'  Parathion costs averaged $l/lb in 1972, while application costs
averaged $.50 per treatment (Chambers et al., 1974).3'

     Using the above cost and price data, the additional income would
amount to $102.98/acre.  Subtracting the cost of parathion at $9.00/acre
would result in an economic benefit of $93.98/acre when parathion was used
to control boll weevils, bollworms, and tobacco budworms.

Sorghum

     Parathion is registered for control of aphids, greenbugs, spider
mites, sorghum webvorms, and sorghum midges on sorghum.  Of these, sorghum
midge and the greenbug are the two insects having the greatest effect on
yield.
I/  Bost, W. M., Director, "Cooperative Extension Service Mississippi
      State University, Mississippi State Mississippi, Summary of Test
      Results at Stoneville and Verona, Mississippi, and Costs of Pesti-
      cides," personal letter to Mr. David F. Hahlen (1974).
|/  U.S. Department of Agriculture, Agricultural Statistics 1973.
3_/  Chambers, William, and Daniel Millel1, Fal'wland Industries, Kansas
      City, Missouri, conversation (1974).
                                    257

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Efficacy Against  Sorghum Midge  Infestation - In the early 1960's the
sorghum midge  temporarily  caused  serious crop losses.  .However, early
uniform planting  has  restricted damage from this Insect to Isolated late
planted fields (Gate  et al.,  1973).17  Huddleston et al. (1972)2/
reported on  tests of  insecticides for control of the midge and concluded
that parathion gave superior  control of midge population with two
applications of 0.5 Ib/acre.

     Yields  from  tests conducted  at Plainview, Texas Increased from 22 to
330 Ib/acre  over  an untreated check as the rate and number of applications
increased.   However,  increasing the rate to 1.0 Ib/acre for two applica-
tions  reduced  the increase to 198 Ib/acre.  In another test conducted in
Texas  in 1961, one application  of 0.5 Ib parathion per acre reduced yields
from the untreated check by 230 bushels per acre.  The authors attributed
this to the  application being made at late bloom.

     Gate et al.  (1971)J/  evaluated several insecticides for control of
the midge in Lubbock  County,  Texas in 1969.  Parathion was applied at 0.5
Ib/acre and  controls  measured for two and three applications.  The first
application  was made  when  50% of  the grain heads were  out of the boot.
The results  showed a  63% control  with two applications and 55% control
with three applications.   Yields  compared to an untreated check Increased
236 Ib/acre  with  two  applications but declined 313 Ib/acre with three
applications.

Cost Effectiveness of Sorghum Midge Control - The tests of Cate et al.
(1973) and Huddleston et al.  (1972) contain the only data found that
compared yields of parathion  treated sorghum plots against an untreated
check.  The  results of these  experiments showed yield  changes ranging from
a loss of 313  Ib/acre to an increase of 330 Ib/acre.
JL/  Cate, J. R., Jr., D. 6. Bottrell,  and  6. L. Teetes,  "Management of  the
      Greenbug  on Grain Sorghum.   I.   Testing Foliar Treatments  of In-
      secticides Against Greenbugs and Corn Leaf Aphids," J. Econ. Entomol.
      66:945-951 (1973)
21  Huddleston, E. W., D. Ashdown, B.  Maunder, C. R. Ward, G. Wilde,  and
      C. E. Forehand, "Biology and Control of the Sorghum Midge.  I.
      Chemical  and Cultural Control  Studies in West Texas," J. Econ.
      Entomol., 65:851-855  (1972).
3/  Cate, J. R., Jr., and D. G. Bottrell,  "Field Evaluation of Insecticide
      Treatments for Control of the  Sorghum Midge," PR-2866, pp.  13-15,
      Research  on Grain Sorghum Insects and Spider Mites in Texas, Texas
      Agr. Exp. Sta.  (1971).
                                     258

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     The price of sorghum averaged $2.25/cwt in 1972.Agricultural.
Statistics 1973 and the cost of parathion was $l/lb (Chambers and Miller)
cost, the economic benefits would range from a loss of $10.04/acre to a
gain of $4.93/acre for control of the sorghum midge.

     These tests are summarized in Table 37.

Table 37.  Results of Parathion Application Sorghum Midge





Additional


Pate
1961
1964



1969

Application
Rate
(Ib Al/acre)
0.5
0.5
1.0
0.5
1.0
0.5
0.5


No.
1
1
1
2
2
2
3
Yield
Increase*
(lb/acre)
(224)
22
154
330
198
236
(313)
income*
$2.25/cwt
($/acre)
(5.04)
0.50
3.47
7.43
4.45
5.31
(7.04)
Application
cost at
AI $l/lb +
treatment at
$ . 50/application
1.00
1.00
1.50
2.00
3.00
2.00
3.00
                                                                   Economic
                                                                   benefit*
                                                                  f$/acre)   Source
                                                                  (5.54)
                                                                   0
                                                                   2.47
                                                                   6.43
                                                                   2.45
                                                                   4.31
                                                                  (8.54)

Data in parentheses indicates decreases in yield, income and economic
     benefit.
aj Huddleston et al., op. clt.  (1972).
b/ Gate et al., op. cit.  (1971).

 Efficacy Against Greenbug Infestation - Although there are numerous
Insects affecting sorghum, perhaps the greenbug  causes the greatest
damage.  Prior to 1968 the greenbug had been found mostly in  small grains
such as wheat, barley, and oats.  However,  in,1968 a new biotype  emerged and
began infesting sorghum.  Ward  et al.  (1970)-  noted that, in 1968,  7.3
million acres became infested resulting in  a production loss  estimated at
$20 million.  Gate et al.  (1979) reported that the Grain Sorghum  Producers
Board estimated that $14 million was spent  for control of grain sorghum pests
in 1970 compared with only $100,000 spent prior  to 1968.
a/
b/
 I/  Ward, C. R., E. W. Huddleston, D. Ashdown,  J.  C.  Owens,  and K.  L.
      Polk, "Greenbug Control  on  Grain  Sorghum  and the Effects of Tested
      Insecticides on Other  Insects," J.  Econ.  Entomol.,  63:1929-1934
      (1970).                                          "
                                     259

-------
      Parathlon gives satisfactory control of greenbugs on sorghum.
 Daniels (1971)1/ conducted two tests at Bushland,  Texas in 1969 and
 achieved a 79% reduction of greenbugs for 29 days  in one test  and an
 897. reduction for 25 days in the other test.  The  first test consisted
 of 0.5 Ib/acre of parathion and the second was at  a  0.25 Ib/acre rate.
 Yield increases were 112 and 42 Ib/acre respectively.

      Gate et al. (1973)  conducted several experiments  for insecticidal
 control of the sorghum greenbug in Lubbock County  Texas in 1968, 1969
 and 1970.   Results showed greenbug control ranging from 657. to 977.
 7 days after application of 0.5 Ib/acre parathion.   Seasonal control
 of greater than 90% was  reported in some of the tests.   Yield  changes
 from the untreated check varied from increases of  32 to 1,083  Ib/acre.
 Ward et al.  (1970) also  showed significant reduction of greenbugs in
 tests at Lubbock and New Deal, Texas in 1968.   Yield increases varied
 widely from a low of 9 Ib/acre to a high of 497 Ib/acre.   Similar
 results were found by DePew (1971)!/ and Harvey et al.  (1970)!/.

      Parathion appears to be phytotoxic to certain types of sorghum.
 Although DePew (.1971)  reported no evidence of  phytotoxicity, Meisch
 et al.  (1970)i/ evaluated various insecticides  for  phytotoxicity to
 six varieties of sorghum and found severe leaf damage  and significant
 yield loss in one variety, but medium to low damage  on the other vari-
 eties.   Yields on the other varieties varied from a  loss of 385 Ib/acre
 compared to  an untreated check to a gain of 408 Ib/acre.
\J  Daniels, N. E., "Insecticidal Greenbug Control in Grain Sorghum,"
      PR-2868, pp. 16-20, Research on Grain Sorghum Insects and Spider
      Mites in Texas, Texas Agr. Exp. Sta. (1971).
2/  DePew, L. J., "Evaluation of Foliar and Soil Treatments for Greenbug
      Control on Sorghum," J. Econ. Entomol.. 64:169-172 (1971).
37  Harvey, T. L., and H. L. Hackerott, "Chemical Control of a Greenbug
      on Sorghum and Infestation Effects on Yields," J. Econ. Entomol.,
      63:1536-1539 (1970).
4/  Meisch, N. V., George L. Teetes, N. M. Randolph, and A. J. Bockholt,
      "Phytotoxic Effects of Insecticides on Six Varieties of Grain
      Sorghum," J. Econ. Entomol.. 63:1516-1517 (1970).
                                 260

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     Cost  Effectiveness of Greenbue Control -  The results of several  tests
     in Texas  and  Kansas  show that  yield changes varied from a  loss of 458
     Ib of sorghum per acre  to a  gain  of 1,083 Ib/acre when parathion  was
     used  to control the  greenbug.

          The  price of sorghum averaged $2.25/cwt  in 1972  (Agricultural
     Statistics 1973); the cost of parathion was $1.00/lb  (Chambers and
     Miller 1974), the cost  of application  is  $.50.   At  these prices and
     costs the economic benefits  would range from  a  loss of  $11.81/acre  to
     a gain of $23.77/acre from the use of  parathion to  control  the greenbug.

          These tests ace summarized in Table  38.

     Table 38.  Results of Parathion Application on  Sorghum Greenbug




Pate
1968

1969
1969





1968

1969
1970



1969
1968
1969



Application
Rate
(Ib Al/acre)
0.5
0.5
0.5
1.0
1.0
1.0
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0.1
0.25
0.5
0.5
0.25
0.25
0.5




No.
1
1
1
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
1


Yield
increase*
(Ib/acre)
497
93
9
(117)
(385)
(458)
(345)
385
408
32
770
47
1,083
1,083
783
1,023
84
439
42
112

Additional
income*
$2.25/cwt
($/acre)
11.18
2.09
0.20
(2.63)
(8.66)
(10*31)
(7.76)
8.66
8.82
0.72
17.33
1.06
24.37
24.37
17.62
23.02
1.89
9.88
0.95
2.52
Application
cost at
Al $l/lb +
treatment at
$ . SO/application
1.00
1.00
1.00
3.00
3.00
3.00
3.00
3.00
3.00
1.00
1.00
1.00
1.00
0.60
0.75
1.00
1.00
0.75
0.75
1.00


Economic
benefit*
($/acre) Source
10.18 a/
1.09
(.80)
(3.63) b/
(9.66)
(11.31)
(8.76)
5.66
5.82
0.72 c/
16.33
0.06
23.37
23.77
16.87
22.02
0.89 d/
9.13 a/
0.20
1.52
*  Data in parentheses indicate decreases in yield, income, and economic
     benefit.
a/  Ward et al.,  op.  cit.  (1970).
b/  Meisch et  al., op. clt.  (1970).
c/  Gate et al.,  op.  cit.  (1973).
d/  Harvey et  al., op. cit.  (1970).
e/  Depew, OP. clt. (1971).
f/  Daniels, op.  clt. (1971).
                                          261

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Wheat

     The  greenbug has been  regarded as  the most destructive of the aphids
infecting small  grains  since  its  introduction into North America in the
19th Century.

Efficacy  Against Pest Infestation -  As a result of a heavy infestation
of greenbugs in  Texas in  1961, Daniels  (1962)=' evaluated several
insecticides for their  control on wheat.  These tests at Bushland, Texas
in 1961 resulted in satisfactory  control with parathion.  In four experi-
ments averages of 88 to 92% reduction of greenbugs were achieved.  Tields
increased between 4.0 and 10.8 bushels/acre respectively.

     Ward et al. (1972)-' screened various insecticides at Clovis, New
Mexico in 1969 and reported a 98% reduction in greenbugs after 14 days
with parathion.  Yields increased by 575 Ib/acre or 9.57 bushels/acre.

3ost Effectiveness of Pest Control - Yield increases based upon the three
rests reported above varied from 4.0 to 10.8 bushels/acre.  At a price of
?1.67/bushel for wheat  in 1972 (Agricultural Statistics 1973)  and an
ipplication cost of $.50 per treatment, a cost of $1.00/lb for parathion
(Chambers and Miller,  1974), the economic benefit would range from $5.68
:o $17.04/acre from control of the greenbug on wheat.

     These are summarized in Table 39.
I/  Daniels, N. E., "Insecticidal Control of the Greenbug,11 Progress
      Report 2247, Texas Agr. Exp. Sta. (1962).
2j  Ward, C. R., J. Owens, D. Ashdown, E. Huddleston, and W. Turner,
      "Greenbug Control on Wheat in 1967-1969." J. Econ. Entomol.. 65:
      764-767 (1972).
                                     262

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     Table 39.   Results of Parathion Application on Wheat Greenbug
        Application
           rate
       (Ib Al/acre)
           0,
           0.
           0.
1968
0.5
0.5
  Yield
 Increase
(bu/acre)

   4.0
   8.0
  10.8
   9.89
   9.57
Addition
income at
$1.67/bu
($/acre)

  6.68
13.36
18.04
16.52
15.98
  Application
  cost at
 AI $l/lb +
$.50/application

  1.00
  1.00
  1.00
  1.00
  1.00
                                                      Economic
                                                      benefit
                                                     ($/acre)   Source
 5.68
12.36
17.04
15.62
14.98
                                                                  a/
b/
     a/  Daniels, op.  cit.  (1962).
     jb/  Ward et al.,  op.  cit (1972).

     Peanuts

     Efficacy Against  Pest Infestation - Parathion is recommended for control of
     the southern corn rootworm on peanuts.   Smith (1971)^'  evaluated several
     insecticides for  control of the rootworm in Virginia In 1965, 1966 and 1967.
     In the 1965 tests, parathion at 2.0 Ib/acre greatly reduced the amount of
     damaged fruit from the untreated checks in two experiments.  The third
     experiment showed a higher rate of fruit damage than the check.  In two
     tests in 1967, parathlon-damaged fruit was reduced over 80% in one test
     but was about the same as the untreated check in the second experiment.
     Yield increases in the latter test were 1.1 Ib/plot or 200 Ib/acre.
     The author could  not explain the lack of control by parathion since typical
     application tests have showed the adult rootworm to be highly susceptible
     to parathion.

     Coat  Effectiveness Of Pest  Control  - The  price of  peanuts  averaged 14.5c/lb
     in 1972  (Agricultural Statistics  1973); the cost of  parathion was  $1.00/lb
     (Chambers  and Miller, 1974).The cost  of application  was  $.50 per treat-
     emtn.  At  these  prices  and  costs  the economic  benefits for the above  test
     amounted to a gain of $26.50/acre.
     I/  Smith, J. C., "Field Evaluation of Candidate Insecticides for Control
           of the Southern Corn Rootworm on Peanuts in Virginia," J. Econ.
           Entomol.. 64:280-283 (1971).
                                          263

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     Corn

          Parathion is registered to control the European corn borer and
     Western corn rootworm, pests significantly affecting corn yields.

     Efficacy Against Pest Infestation - Munson et al.  (1970)-  evaluated
     several insecticides for control of these pests in 1964 and 1965 at
     selected locations in Iowa.  At Sanborn, Iowa in 1964,  parathion at 1.0
     Ib/acre gave significant reductions in corn borer cavities and  signifi-
     cantly lower net root ratings for corn rootworm control.   Yields
     increased 113 and 97 bushels/acre over an untreated check for two  plots
     with parathion applied at different dates.  The lower yield increase
     occurred on the later date.

          An experiment at Hamburg,  Iowa in 1965 also showed significant
     reductions in net root ratings  and corn borer cavities  over the untreated.
     Yields, however, increased 10 and 5 bushels/acre over the untreated check
     for applications at different dates.   The author concluded that one
     application of parathion can effectively control these  pests.

    Cost Effectiveness Of Pest  Control - The price of corn averaged $1.20/bushel
    in 1972  (Agricultural Statistics 1973); the cost of parathion was $l/lb
     (Chambers and Miller,1974).  The cost of application was $.50 per treatment.
    At these prices and costs the economic benefits ranged from $4.95 to
    $143.27/acre.

    These  results  are summarized in Table  40.
    Table  40.   Results  of  Parathion Application on Corn Insect Pests
        Application      Yield
          rate         increase
Date   (Ib Al/acre)    (bu/acre)

1964        1.0         113
            1.0          97
1965        1.0          10
1965        1.0           5
  Additional    Application
  income at    cost at
 $1.29/bu    AI $l/lb +
($/acre)   $.50 Application
  144.77
  125.13
   12.90
    6.45
                 Economic
                 benefit
                ($/acre)   Source
1.50
1.50
1.50
1.50
143.27
123.63
 11.40
  4.95
    a/  Munson et al., op. cit. (1970).
    I/  Munson, R. E., T. A. Brindley, D. C. Peters, and W. G. Lovely, "Control
          of Both the European Corn Borer and Western Corn Rootworms with One
          Application of Insecticide," J. Econ. Entomol.. 63:385-390 (1970).
                                           264

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    Potatoes

    Efficacy Against Wireworm Infestation. -  Parathion is recommended.for
    control of the Pacific wireworm in the Northwest.   Onsager (1969)-'
    conducted experiments in 1965,  1966 and 1967 to evaluate insecticides
    for control of the wireworm in Eastern Washington.  Parathion effectively
    controlled the wireworm as measured by a reduction in culls over an untreated
    check.  Culls were reduced between 78 and 95% in the three tests.  However,
    there appears to be no relation between yield and wireworm control since
    yields varied from a loss of 3,900 Ib/acre to a gain of 4,400 Ib/acre.

    Cost Effectiveness of Wireworm Control - The price received for potatoes
    amounted to $2.55/cwt in 1972 (Agricultural Statistics 1973).  The cost
    of parathion was $l/lb (Chambers and Miller, 1974).  The cost of application
    was $.50 per treatment.  At these prices and cost, the economic benefits
    vary from a loss of $103.45 to a gain of $108.70/acre from the use of
    parathion to control the wireworm.

    These results are summarized in Table 41.

    Table 41.  Results of Parathion Application for Wireworm Control.


                                  Additional      Application
       Application     Yield*      income at*      cost at           Economic
         rate         increase      $2.55/cwt     AI $l/lb +         benefit*
Date   (Ib Al/acre)   (cwt/acre)   ($/acre)   at $A50/appllcation    ($/acre)   Source

1965     3.5             (39)         (99.45)       4.00               (103.45)    a_/
1966     4.0               2           5.10        4.50                 9.60
1967     3.0              44         112.20        3.50               108.70
*  Data in parentheses indicate decreases in yield, income and economic
     benefit.
a/ Onsager, op. cit. (1969).
if  Onsager, J. A., "Nonpersistent Insecticides for Control of Pacific
      Coast Wireworm," J. Econ. Entomol.. 62:1065-1067  (1969).
                                          265

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Potato Aphid Control - The results of a test reported in American
Cyanamid Pesticide Petition  19-'  showed that a 15% parathion wettable
powder applied at a rate of  1 lb/100 gal.  (~0.15 Ib/acre) in six
applications to potatoes for control of the potato aphid in New York
yielded an  average of AOO bu/acre compared to an untreated check
yield of 340 bu/acre.  This  is an increase of 60 bushel for 3,600
Ib/acre which results in an  economic benefit of $87.90/acre.

Leafhopper  Control - In the  same  petition parathion  (15% wettable powder)
was  tested  for control of the potato leafhopper in Ohio in 1950.  The
insecticide was applied three times at a rate of 1 lb/100 gal.  (~0.15
Ib/acre) resulting in a yield of  733 bushels/acre compared to an un-
treated check which yielded  402 bushels.  The application of 0.45 Ib of
parathion produced a 331 bushel  (19,860 Ib) yield increase resulting in
an economic benefit of $504.48/acre.

Lima Beans  -  The lygus hesperus  is a significant pest affecting yields
of lima beans.  Bushing et al.  (1974)2' evaluated insecticides for
control of  this pest at Davis, California, between 1969 and 1971 and
concluded that parathion applied  at about the period of first bloom
increased yields significantly.   The results of one  test showed a
yield increase of 2,305 Ib/acre with the application of parathion.
It had to be applied three times  at 0.5 Ib/acre because populations
rebounded to new highs very  quickly after each application.

     The price of lima beans was  $208.00/ton in 1972  Agricultural
Statistics  1973; the costs of parathion was $l/lb (Chambers and Miller,
1974; the cost of application was $.50 per treatment.  Using these prices
and  costs the additional income from this test which yielded 2,305 Ib/acre
would be $239.72/acre.  Subtracting the cost of parathion of $236.22/acre.
I/  American Cyanamid Company, Pesticide Petition No. 19, Malathion -
      Summary of Data, EPA Registration Files.
2j  Bushing, R. W., and V. E. Burton, "Partial Pest Management Programs
      on Dry Large Lima Beans in California:  Regulation of L_. hesperus,"
      J. Econ. Entomol.. 67:259-261  (1974).
                                     266

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    Peas

         One test result was available from the EPA files regarding parathion
    use on peas to control the pea aphid.   American Cyanamid Pesticide Petition
    252^' reported that the yield of peas  when treated with 40 Ib/acre of 1%
    parathion dust in a Maryland test in 1951 was 29.5 Ib/plot.   A comparable
    untreated check yielded 20.1 Ib for an increase of 9.4 Ib.

         In  1972  peas sold  for an average of $112/ton and yields were  1.36
    tons/acre  (Agricultural Statistics 1973).  Using the yeild increase of
    44.8% from the above  test and the price of $112/ton this would result in
    yield increase of 0.61  tons or  $68.42/acre.  At a cost of  parathion of
    $l/lb (Chambers and Miller, 1974) and application cost of  $.50 per
    treatment,  the resultant economic benefit would be $67.52/acre.

    Strawberries

         Schaefers et al.  (1972)2/ evaluated parathion for control of the
    tarnished plant bug on strawberries and concluded that two applications
    of parathion at 0.5 Ib/acre appeared to provide satisfactory reduction
    in injury, but the advantages of such  a program was not evident.  These
    results are summarized in Table 42.

    Table 42.  Results of Parathion Application on Strawberry/Tarnished Plant Bug.
Date
1971
Application
rate
s (Ib Al/acre)
0.5
0.5
check
0.5
check


No.
2
1
—
1
—
Number
of
berries
8,065
8,019
8,652
2,721
2,132

Injury
(%)
24
34
55
35
71
Increased
yield
(%)
31
21
—
36
—


Source
a/




a_/  Schaefers, op cit. (1972).

        The prices received for strawberries  in  1972 averaged  $24/cwt  and
   yields averaged 105 cwt/acre (Agricultural Statistics  1973).   The yield
   increases  from the above tests ranged  from 21% to 36%  over  the untreated
   berries.   At  an income  of  $2,520  Ib/acre of berries, the additional income.
if  American Cyanamid Company, Pesticide Petition No. 252, Malathion -
      Summary of Data, EPA Registration Files.
2J  Schaefers, G. A., "Insecticidal Evaluations for Reduction of Tarnished
      Plant Bug Injury in Strawberries," J. Econ. Entomol.. 65:1156-1160.
      (1972).
                                       267

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from parathion use at the above yield increases would range from $529.20
to $907.20/acre.  Subtracting the parathion costs of $l/lb and the
application cost of $.50 per treatment, the economic benefit would range
from $527.70 to $905.70 acre.
                                          268

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References

Adkisson, Perry L., and S. J. Nemec, "Comparative Effectiveness of
  Certain Insecticides for Killing Bollworms and Tobacco Budworms,"
  Publication B-1048, Texas Agr. Exp. Sta. (1966).

Adkisson, Perry L., and S. J. Nemec, "Insecticides for Controlling the
  Bo11worm, Tobacco Budworm, and Boll Weevil," MP-837, Texas Agr. Exp.
  Sta. (1967).

Agricultural Statistics, 1973, U.S. Department of Agriculture (1973).

American Cyanamid Company, Pesticide Petition No. 19, Malathion -
  Summary of Data, EPA Registration Files.

American Cyanamid Company, Pesticide Petition No. 252, Malathion -
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Bost, W. M., Director, "Cooperative Extension Service Mississippi State
  University, Mississippi State Mississippi, Summary of Test Results at
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  letter to Mr. David F. Hahlen  (1974).

Bushing, R. W., and V. E. Burton, "Partial Pest Management Programs on
  Dry Large Lima Beans in California:  Regulation of L. hesperus,"
  J. Econ. Entomol.. 67:259-261  (1974).

Gate, J. R., Jr., and D. 6. Bottrell, "Field Evaluation of Insecticide
  Treatments for Control of the  Sorghum Midge," PR-2866, pp. 13-15,
  Research on Grain  Sorghum Insects and Spider Mites  in Texas, Texas
  Agr. Exp. Sta.  (1971).

Gate, J. R., Jr., D. G. Bottrell, and G.  L. Teetes,  "Management  of  the
  Greenbug on Grain  Sorghum.  I.  Testing Foliar  Treatments  of In-
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Chambers, William, and Daniel Miller, Farmland  Industries, Kansas City,
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  2868,  pp. 16-20, Research  on  Grain Sorghum Insects and Spider Mites
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Daniels, N. E.,  "Insecticidal Control of  the Greenbug," Progress Report
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                                 269

-------
 DePew,  L.  J.,  "Evaluation of Foliar and Soil Treatments for Greenbug
   Control  on Sorghum," J. Econ.  Entomol..  64:169-172 (1971).

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 Meisch, N. V., George L. Teetes, N. M. Randolph,  and A. J. Bockholt,
   "Phytotoxic  Effects of Insecticides on Six Varieties of Grain Sorghum,"
   J.  Econ. Entomol.. 63:1516-1517 (1970).

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   of  Both  the  European Corn Borer and Western Corn Rootworms With One
   Application of Insecticide," J. Econ. Entomol.. 63:385-390 (1970).

 Onsager, J. A., "Nonpersistent Insecticides for Control of Pacific Coast
   Wireworm,"  J. Econ. Entomol..  62:1065-1067 (1969).

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   of  H.  virescens  as Compared With H. zea to Organophosphate Insecticides,"
   J.  Econ. Entomol., 64:999-10002 (1971).

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   Plant  Bug Injury in Strawberries," J.  Econ. Entomol., 65:1156-1160
   (1972).

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  The Southern Corn Rootworm on Peanuts in Virginia," J. Econ. Entomol.,
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Ward,  C. R., E. W. Huddleston, D. Ashdown,  J. C.  Owens, and K. L.  Polk,
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                                     270

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Ward, C. R., J. Owens, D.  Ashdovm, E.  Huddleston, and W. Turner,  "Green-
  bug Control on Wheat in  1967-1969," J. Econ. Entomol., 65:764-767 (1972)

Wolfenbarger, D. A.,  "Tobacco Budworm:  Cross Resistance to  Insecticides
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                                      271
                                                    Ui GOVERNMENT PRINTING OFFICE: 19»-

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