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               AIR POLLUTION ASPECTS

                        OF

           PHOSPHORUS AND ITS COMPOUNDS
                 Prepared for the
  National Air Pollution Control Administration
Consumer Protection & Environmental Health Service
   Department of Health, Education, and Welfare
           (Contract No. PH-22-68-25)
        Compiled by Yanis C. Athanassiadis
              Litton Systems, Inc.
         Environmental Systems Division
               7300 Pearl Street
            Bethesda, Maryland 20014

                 September 1969

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                          FOREWORD


       As the concern for air quality grows, so does the con-

cern over the less ubiquitous but potentially harmful contami-

nants that are in our atmosphere.  Thirty such pollutants have

been identified, and available information has been summarized

in a series of reports describing their sources, distribution,

effects, and control technology for their abatement.

       A total of 27 reports have been prepared covering the

30 pollutants.  These reports were developed under contract

for the National Air Pollution Control Administration  (NAPCA) by

Litton Systems, Inc.  The complete listing is as follows:


    Aeroallergens (pollens)       Ethylene
    Aldehydes (includes acrolein  Hydrochloric Acid
      and formaldehyde)           Hydrogen Sulfide
    Ammonia                       Iron and Its Compounds
    Arsenic and Its Compounds     Manganese and Its Compounds
    Asbestos                      Mercury and Its Compounds
    Barium and. Its Compounds      Nickel and Its Compounds
    Beryllium and Its Compounds   Odorous Compounds
    Biological Aerosols           Organic Carcinogens
      (microorganisms)            Pesticides
    Boron and Its Compounds       Phosphorus and Its Compounds
    Cadmium and Its Compound.s     Radioactive Substances
    Chlorine Gas                  Selenium and Its Compounds
    Chromium and Its Compounds    Vanadium and Its Compounds
      (includes chromic acid)     Zinc and Its Compounds


       These reports represent current state-of-the-art

literature reviews supplemented by discussions with selected

knowledgeable individuals both within and outside the Federal

Government.  They do not however presume to be a synthesis of

available information but rather a summary without an attempt

to interpret or reconcile conflicting data.  The reports are

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necessarily limited in their discussion of health effects for

some pollutants to descriptions of occupational health expo-

sures and animal laboratory studies since only a few epidemio-

logic studies were available.

       Initially these reports were generally intended as

internal documents within NAPCA to provide a basis for sound

decision-making on program guidance for future research

activities and to allow ranking of future activities relating

to the development of criteria and control technology docu-

ments.  However, it is apparent that these reports may also

be of significant value to many others in air pollution control,

such as State or local air pollution control officials, as a

library of information on which to base informed decisions on

pollutants to be controlled in their geographic areas.  Addi-

tionally, these reports may stimulate scientific investigators

to pursue research in needed areas.  They also provide for the

interested citizen readily available information about a given

pollutant.  Therefore, they are being given wide distribution

with the assumption that they will be used with full knowledge

of their value and limitations.

       This series of reports was compiled and prepared by the

Litton personnel listed below:

       Ralph J. Sullivan
       Quade R. Stahl, Ph.D.
       Norman L. Durocher
       Yanis C. Athanassiadis
       Sydney Miner
       Harold Finkelstein, Ph.D.
       Douglas A. Olsen, Ph0D.
       James L. Haynes

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       The NAPCA project officer for the contract was Ronald C.



Campbell, assisted by Dr. Emanuel Landau and Gerald Chapman.



       Appreciation is expressed to the many individuals both



outside and within NAPCA who provided information and reviewed



draft copies of these reports.  Appreciation is also expressed



to the NAPCA Office of Technical Information and Publications



for their support in providing a significant portion of the



technical literature.

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                          ABSTRACT






       High concentrations of phosphorus and its compounds,




especially yellow elemental phosphorus, may cause adverse




physiological effects ranging from skin irritation to systemic




poisoning.  In very low concentrations, many of the organic




and some of the inorganic compounds of phosphorus inhibit




basic metabolic processes in mammals, especially the enzymatic




activity of cholinesterases.




       In vegetation, high concentrations of phosphorus in-




duce a deficiency of zinc, copper, and molybdenum, resulting




in reduced growth.




       Certain phosphorus compounds—for example, phosphoric




acid—are also quite corrosive to materials.




       The major sources of phosphorus air pollution are the




industries engaged in the production of phosphate fertilizers,




phosphoric acid, phosphorus pentoxide, and phosphorus chemicals




for industrial uses.  The application of organophosphorus




pesticides may also result in environmental air pollution.




This is discussed in the companion report, "Air Pollution




Aspects of Pesticides . "




       Recently, various organic phosphorus compounds have been




used as combustion chamber deposit modifiers as well as corro-




sion inhibitors for motor gasolines and aviation fuels.  Thus




there is a possibility that automobile emissions may contain




toxic phosphorus compounds.

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        Phosphorus concentrations in the ambient air of Los



Angeles (1954) and Cincinnati (1966) were found to average



1.43 |J,g/m3 , and 0.22 |ag/m3 , respectively.  Measurements on



national or regional scales are not available.



        No information has been found on economic costs of



phosphorus air pollution.  Investment in air pollution control



equipment within the phosphate industry has been relatively



high, especially in Florida, where the phosphate fertilizer



industry is concentrated.  Operating costs of control equip-



ment in this  section of the fertilizer industry have been



estimated at  $6 million annually; this also includes the



control of fluoride emissions.



        Most  of the abatement systems used in the phosphorus



industry are  not specific for phosphorus, since often the



major pollutant is fluoride emissions (in the phosphate fer-



tilizer industry).  Those systems which are used include



combinations  of scrubbers; cyclones; mist eliminators; high-



energy, wire-mesh contactors; and electrostatic precipitators.



        Methods available for quantitative analysis of



phosphorus in the atmosphere include colorimetric (molybdenum



blue method), fluorescent, and spectrophotometric methods.



Some of these methods permit determinations down to the micro-



gram level.

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                         CONTENTS

FOREWORD

ABSTRACT

1.  INTRODUCTION 	    1

2.  EFFECTS	    3

    2.1  Effects on Humans	    3
         2.1.1  Elemental Phosphorus 	    4
         2.1.2  Inorganic Compounds  	    5
         2.1.3  Organic Compounds  	    7
    2.2  Effects on Animals	   11
         2.2.1  Commercial and Domestic Animals  ....   11
         2.2.2  Experimental Animals 	   12
                2.2.2.1  Inorganic Compounds 	   12
                2.2.2.2  Organic Compounds 	   14
    2.3  Effects on Plants	   15
    2.4  Effects on Materials	   18
    2.5  Environmental Air Standards 	   18

3.  SOURCES	   20

    3.1  Natural Occurrence  	   20
    3.2  Production Sources  	   20
    3.3  Product Sources	   23
         3.3.1  Phosphoric Acids 	   23
         3.3.2  Phosphate Fertilizers  	   24
         3.3.3  Phosphine	   25
    3.4  Other Sources	   26
         3.4.1  Oil-Fired Boilers  	   26
         3.4.2  Iron and Steel Industry	   26
         3.4.3  Transportation Sources 	   27
    3.5  Environmental Air Concentrations  	   28

4.  ABATEMENT	   30

5.  ECONOMICS	   32

6.  METHODS OF ANALYSIS	   34

    6.1  Sampling Methods  . . .	   34
         6.1.1  Free Phosphorus  in Air	   34
         6.1.2  Phosphoric Acid  (Plants, Stack Gasses)  .   34
         6.1.3  Phosphine	   35

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                   CONTENTS (Continued)


    6.2  Quantitative Methods  	   35
         6.2.1  Phosphorus and Phosphoric Acid	   35
         6.2.2  Phosphine	   37
         6.2.3  Organophosphorus Pesticides  	   37

7.  SUMMARY AND CONCLUSIONS	   38

REFERENCES

APPENDIX

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                       LIST OF FIGURES
1.  Marketed Production, Apparent Consumption, and
    Exports of Phosphate Rock, 1900-66 	   49

2.  Flow Diagram of Phosphate Rock Storage and
    Grinding Facilities  	   50

3.  Flow Diagram of Process for Production of Super-
    phosphoric Acid	„ .   51

40  Flow Diagram of Wet Process Phosphoric Acid
    Plant	   52

5.  Flow Diagram of Furnace Phosphoric Acid Plant  ...   53

6.  Flow Diagram:  Production of Run of Pile and
    Granular Triple Superphosphate 	   54

7.  Flow Diagram of Normal Superphosphate Plant  . « 8 •   '55

8.  Cumulative Particle Size Distribution of Phosphate in
    Cincinnati and Fairfax, Ohio	   56

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                      LIST OF TABLES

1.  Effects of Excessive Application of Phosphate on
    Sour-Orange Seedlings 	   16

2.  Threshold Limit Values for Phosphorus and Certain
    Compounds	19

3.  Emissions and Abatement Devices Used in Seven
    Phosphate Fertilizer Plants 	   31

4.  Properties/  Toxicity, and Uses of Phosphorus and Some
    Phosphorus Compounds  	   57

5.  Comparative Acute Toxicity of Cholinergic
    Organophosphous Insecticides in Normal Male and Female
    Rats	68

6.  Comparative Toxicities of Some Phosphorus Compounds
    for Experimental Animals  	   69

7.  Production of Phosphorus Chemicals	72

8.  Growth of Phosphoric Acid Industry in United States . .   73

9.  Thermal-Process Phosphoric Acid Establishments in
    United States 	   74

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1.  INTRODUCTION



            Phosphorus and its compounds have varying  effects



    depending upon the chemistry and concentration.  For  example,



    yellow (white) phosphorus is a protoplasmic poison, while



    red phosphorus is not; and some of the organic and inorganic



    compounds of the element are comparatively nontoxic even at



    the gram level, while some others are highly toxic in con-



    centrations at the microgram level.  Very few of the  known



    phosphorus compounds have been investigated with respect to



    their toxic effects.



            The adverse effects on humans and animals  exposed to



    concentrations of phosphorus vary from a slow, cumulative and



    mostly irreversible inhibition of cholinesterase activity to



    death from poisoning, depending basically on the physico-



    chemical form of the elements and its concentration.   The



    human nervous system is the most affected by high  concentra-



    tions of phosphorus.



            The compounds known to be emitted in appreciable



    quantities into the ambient air are phosphorus oxides,  phos-



    phoric acid, and the organophosphorus compounds, found mostly



    in agricultural chemicals.  Other organic phosphorus  compounds



    are very probably emitted into the ambient air by the



    chemical industry from processes in which phosphorus  products



    are intermediate and/or final outputs.

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        The potential of phosphorus and its compounds as  air



pollutants may possibly be increasing,  since production of



phosphate rock has increased by more than 200 percent since



1950.  This may pose a pollution problem in the areas where



industrial emission sources are concentrated.  Also,  the  use



of phosphorus compounds as additives in gasoline and aviation



fuels may pose a problem.



        In this report the phosphorus compounds will  be



divided into two main groups for discussion—the inorganic



phosphorus compounds and the organic phosphorus compounds.

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2.   EFFECTS




            Elemental phosphorus (yellow) is a protoplasmic



    poison.  Some of its compounds,  especially organic phosphates,



    can also be lethal to man and animals in the case of  exposure



    to high air concentrations.   Exposure to relatively low con-



    centrations can produce serious  disturbances of basic meta-



    bolic processes.  Acute or chronic effects from ambient air



    concentrations have been studied only with respect to



    organophosphorus pesticides.  Such studies are few and do



    not provide data on concentrations; however, they have



    established that the symptoms observed are specific for and



    quite similar to those found in  experimental studies  on the




    toxicity of organophosphorus compounds.



    2.1  Effects on Humans



            The adverse effects of human exposure to high concen-



    trations of phosphorus and its compounds vary widely  both



    in intensity and type, depending on the physicochemical form



    of phosphorus.  Some of the organic compounds of phosphorus



    are known to be harmless to humans, while others have been



    shown to be highly toxic.  The known adverse bioeffects of



    phosphates at the molecular level include inhibition  of a



    number of important enzymatic activities.  The properties,



    toxicity, and uses of phosphorus and certain of its compounds



    are given in Table 4 in the Appendix.

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 2.1.1  Elemental Phosphorus



        There are three different types of elemental phospho-



 rus:  yellow (white), red, and black; each has substantially



 different physicochemical and biological properties, some of



 which are not yet well understood.



        Elemental yellow phosphorus is an extremely toxic



 substance considered to be a protoplasmic poison.   Its toxic



 effect is apparently due to its potent reducing properties,



 which cause disturbances of intracellular oxidation pro-

         47
 cessess.    Chronic exposure to small quantities of phospho-



 rus causes epithelial damage of the bone capillaries with


                              47
 thrombosis and bone necrosis.



        The heart is one of the organs affected by phosphorus,



 and several electrocardiographic anomalies have been reported



 after exposure to phosphorus.12'14'15'50  In a total of 115



 patients who attempted suicide with "electric paste" (rat



 poison containing 2.5 percent phosphorus), 35 (30 percent)


                                                 14 15
; died, mostly from acute cardiovascular collapse.  '



        Red phosphorus is considered comparatively harmless;



 however, inhalation of its dust has been reported to cause


      i  .  47
 pneumonia.


        Black phosphorus is an allotropic form that is synthe-



 sized under high laboratory pressures and is not found under



 normal conditions of temperature or pressure.

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2.1.2  Inorganic Compounds



        Phosphine (PHs) is a very toxic gas which ignites



spontaneously in air.  This gas produces chronic effects



similar to that observed with phosphorus.52  Acute effects



of phosphine inhalation include dyspnea, weakness, vertigo,



bronchitis, edema, convulsions, and death.  The odor thresh-



old is 2 ppm (2.6 |J.g/m3 by volume).29  Phosphine acts on the



central nervous system and the blood.  A concentration of



2,000 ppm (2,860,000  p.g/m3 ) is lethal to man in a few minutes.



Concentrations from 400 to 600 ppm (572,000 to 878,000



|jg/m3 ) are dangerous to life after exposures of 30 to 60



minutes.  The maximum concentration tolerated for a 1-hour



exposure is in the range of 100 to 190 ppm (143,000 to 271,000



l_ig/m3 ), and the maximum that can be tolerated for several



hours without appearance of symptoms is 7 ppm (10,010 |ag/m )-27



        Phosphorus trichloride (PC13) enters the body as a



vapor through the respiratory tract, causing suffocation,



bronchitis, edema, and inflammation of the lungs.  The



vapors of PCla are irritating to skin, mucous membranes/



and the respiratory tract.27'31'51  Exposure to the vapors



may result in cough, painful inflammation of the eyes,



burning in nose and throat, bronchial catarrh, dyspnea, and



after severe exposure, death.23'52'62  A concentration of



600 ppm (3,600,000 |-ig/m3 ) is lethal within a few minutes.

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Concentrations of 50 to 80 ppm (300,000 to 480,000 Ug/m3)



are injurious after an exposure of 30 to 60 minutes.   The



range of concentrations from 2 to 4 ppm (12,000 to 24,000



Ug/m"3 ) can be tolerated for exposures of as long as 60



minutes without serious symptoms.2^



        Phosphorus pentachloride (PCls) is also poisonous,



causing adverse physiological effects similar to those



described for phosphorus trichloride.2?



        Phosphorus oxychloride (POCls) is also poisonous



and causes symptoms similar to those described for phosphorus



trichloride.    In the same manner, the vapors of POC13 are



irritating to skin, mucous membrances, and the respiratory



tract.26'2^  Exposure to vapors may again result in cough,



painful inflammation of the eyes, burning in nose and



throat, bronchial catarrh, dyspnea, and after severe exposure,



death.23'52'62



        Zinc phosphide (Zn3?2), which is extremely toxic,



may give off phosphine and accidentally cause fatalities.




        Tricalcium phosphate (Ca3(PC>4)2) is used in the



production of some dentifrices and may cause a problem



because of its low solubility (0.002 percent).  Crystals of



tricalcium phosphate were found in the viscera, lymph nodes,



and enteric mucosa of a patient who died from carcinomatosis.



The presence of these crystals was explained as the result

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of  excessive  and  careless use of a "shake-out" denture



cleaner powder.   Most of the particles of this powder were



smaller than  5 u* and probably were inhaled.  To test the



hypothesis that tricalcium phosphate crystals were associated



with the observed systemic lesions and cancer, experiments



were condudted with white rats63 (see Section 2.2).




        Inhalation of the dust of calcium phosphate rock has



been found to affect the respiratory system adversely-  Com-



parison of the ventilatory capacity of 18 men before and



after exposure to dust revealed that there was a significant



decrease in the forced expiratory volume after exposure to



the dust over several hours; greater and more consistent



decreases were observed in those men who had a history of



persistent cough  accompanied by sputum.21  Phosphate rock



dust may also be  emitted in significant quantities from



fertilizer manufacturing plants.



2.1.3  Organic Compounds



        The effects of exposure to organic phosphorus com-



pounds through inhalation vary from acute systemic poisoning



to slow and cumulative inhibition of basic metabolic processes.



The most well-studied effect is the inhibition of cholines-



terase activity.   Cholinesterase (specific,  true, or acetyl-



cholinesterase)  is an enzyme located in most tissues,  especially



conductive tissues (brain and nerves),  erythrocytes, skeletal
        *ia=micron.

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                                                            8
muscles, adrenal and salivary glands, lungs, liver, and




stomach.  The enzyme hydrolyzes acetycholine to acetate plus



choline, and in addition, splits other choline esters.



Organophosphorus compounds also inhibit pseudocholinesterases



(nonspecific), and some compounds are effective in extremely



low concentrations.  For example, tetraethyl pyrophosphate is



an effective inhibitor at a molar concentration of 10~16, and



this effect appears to be irreversible.37



       Analysis of the enzymatic action of cholinesterase has



shown that when the enzyme reacts with alkylphosphate, it be-



comes phosphorylated.  The result is a phosphorylated enzyme



which, in contrast to cholinesterase, does not react with



water.  Since its active side is thus blocked, it becomes



deactivated.



       The inhibition of cholinesterase by alkylphosphates



may lead to accumulation of acetylcholine in synaptic junctions



and thus lead to hypersensitivity-  Acetylcholine also accu-



mulates at the endings of the postganglionic cholinergic



nerves; at muscular end-plates; and in the brain.  The toxicity



in man and warm-blooded animals is extraordinarily high.  The



acetylcholine at the end-plates of skeletal muscles leads to



muscular weakness and possibly tonic-clonic convulsions.  In



acute poisoning, cholinesterase is distinctly reduced (by more1



than 20 percent) but falls more rapidly in the plasma than in



the erythrocytes.   In chronic poisoning,  the determination

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of erythrocyte cholinesterase is considered a more reliable



indicator than the determination of plasma cholinesterase.


                                      72
       A follow-up study in California   (1963-1964) investi-



gated the cases of 235 individuals who reportedly were occu-



pationally exposed to organic phosphates in 1960.  About two-



thirds of these cases occurred in agricultural workers, and



the remaining third among workers in chemical companies, State



and local governments, nurseries, packing houses, and pest



control operations.  The study was based on personal interviews



by a physician, limited physical examination, and laboratory



measurements, including determination of blood cholinester-



ase activity in two 5-ml samples of blood and in a number of



samples, measurements of serum glutamine oxaloacetic trans-



aminase, serum glutamic pyruvic transaminase, thymol turbidity,



and packed red blood cell volumes (hematocrits).  The effects



of acute, systemic insecticide poisoning varied, and the



cases were divided into the following categories:



       In Group 1 (87 cases), the symptoms included effects of



parasympathetic stimulation such as headache, nausea, weakness,



chest pain, vertigo, vomiting, nervousness, sweating, disturbed



vision, shortness of breath, and excessive salivation.  These



symptoms were confirmed by depressed blood cholinesterase



levels.



       In Group 2 (91 cases) the above described symptoms of



parasympathetic stimulation were also observed, but without



laboratory confirmation.

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                                                           10
       In Group 3 (57 cases), no information on symptoms and

laboratory findings was provided.  However, organic phosphate

poisoning was reported.

       Of the total 235 cases originally reported, only

114 individuals stricken with acute organic phosphate

poisoning were located and interviewed.  The insecticides

implicated were as follows:

                   Parathion            36 cases
                   Phosdrin             30 cases
                   Thimet               12 cases
                   Systox                5 cases
                   TEPP                  2 cases
                   Trithion              2 cases
                   Malathion             3 cases
                   Phosphamidon          1 case
                   Combinations         23 cases

       Exposure to these compounds varied.  The majority of

persons studied (74.6 percent) were directly exposed through

mixing and loading of aerial sprays, ground spraying, and

work in chemical plants.  Another group (22.8 percent) was

indirectly exposed as a result of picking fruits and vete-

tables, planting, irrigating, cultivating, and walking

through the fields.  The remainder (2.6 percent) were exposed

by incidental contact.  For the 114 cases traced, 72 blood

analyses were made, and 57 of these showed low cholinesterase

activity.  Of the 114 individuals, 20 could no longer tol-

erate smelling or contact with insecticides:  12 persons

experienced nausea and/or vomiting after even a whiff of these

substances, and five others developed headache.  Many indivi-

duals had avoided reexposure by shifting to other work.

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                                                           11
However, two-thirds returned to work, and 10 of these


experienced subsequent attacks of acute poisoning.


       A study   was made of a group of patients with chronic


trieresyl orthophosphate  (C2iH21O4P) poisoning who had been


taking this organophosphorus drug orally in doses of 200 |ig.


Six of the patients showed symptoms of central and peripheral


nervous system damage in the form of a psychoorganic syndrome


accompanied by sexual and various nervous disorders.  The


symptoms of mental disorders were at onset similar to those


of neurasthenia; however, the full clinical picture developed


only after 4 years.  Sexual disorders consisted of an increase


in libido, which gradually developed into complete impotence.


       More detailed information on the effects of organo-


phosphate compounds can be found in the companion report on


pesticides.


2.2  Effects on Animals


2.2.1  Commercial and Domestic Animals

               I O
       Einbrodt   studied the effects on horses of mine dust


containing phosphorus pentoxide.  Analysis of the lungs of


three mine horses (in Germany) showed average concentrations


of phosphorus pentoxide amounting to about 20 percent of the


total dust content of the lungs.  The highest concentration


of phosphorus pentoxide was found in the bronchi (23 to 29

      4.\ 18
percent).

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                                                           12
2-2.2  Experimental Animals



2-2.2.1   Inorganic Compounds



       Phosphorus trichloride  (PC13) hydrolyzes rather rapidly,



producing hydrogen chloride and phosphorus acid (H3PO3).  When



the hydrolysis takes place in  the presence of moist air, fumes



are produced.



       Experiments in which 10 rats and 10 guinea pigs inhaled



dispersed PC13 vapors at concentrations of 300,000 to 600,000



Hg/m3  (total particulate) gave the following results.  During



exposure, the animals were restless and nervous, and porphyrin



secretions developed around their eyes.  The nostrils and paws



were swollen and edematous shortly after exposure and necrosis



was observed in the nasal epithelium and its substructure.



The major histological alterations observed consisted of



nephrosis of the kidney tubules in the corticomedullary region.



All animals died within a 10-day period after exposure.  In



the case  of animals exposed to ammoniated PC1_ at concentra-


                                   . o

tions of  1,100,000 to 2,500,000 ng/m , some animals died within



3 days after exposure.  All animals developed severe pulmonary



edema while the lungs of the animals which survived exposure


                                                         79
showed extensive areas of fibrosis in the alveolar walls.



       The hydrolysis of phosphorus oxvchloride (POC13) occurs



rapidly in water, and quickly enough on contact with moist air



to cause  fuming.  The hydrolysis results in the formation of


                                                    79
hydrogen  chloride (HCl) and phosphoric acid (H3PO4).

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                                                           13
       Other experiments in which 10 rats and 10 guinea pigs



inhaled POC13 vapors at concentrations of 30,000 \J.g/m3 (total




particulate) gave the following results.  During exposure,



the animals were restless and nervous, and porphyrin secre-



tions developed around the eyes.  All deaths occurred within



48 hours after exposure.  The signs of toxicity gradually



abated in surviving animals and disappeared by the end of the



14-day experimental period.  The lungs of the dead animals



were dark red and showed plugs in the lumen of bronchi and



bronchioles, while the alveolar spaces around the lumen plugs



were edematous and hemorrhagic.  Animals exposed to aerosols



from the dispersion of ammonia-neutralized POC1., showed the



same pattern of survival times and histological changes as



the animals exposed to pure vapors of POC13.



       Tricalcium phosphate, of the type and particle size



(0.1 to 5 |~i) contained in some toothpastes, was fed to 12



white rats for periods of 3 days to 7 weeks; another 21 rats



were injected with 50,000 |_ig of a denture cleanser that con-



tained tricalcium phosphate.  Examinations showed that crystals



of the phosphate had entered the intestinal mucosa of the rats



after ingestion and the lungs after injection.  These crystals



were deposited in tissues and caused mild or severe inflamma-



tion and granulomas.    However, the results of these experi-



ments were inconclusive with respect to a possible causal



relation between cancer and the tricalcium phosphate crystals.57

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                                                          14
2.2.2.2  Organic Compounds



       The toxicity of the organic phosphorus derivatives to



mammals is directly proportional to the inhibition of acetyl-



cholinesterase produced.  The phosphorus insecticides act by



deactivating  (phosphorylating) the enzymes they attack.  A



lowering of mammalian toxicity was achieved in recent years



by using pesticides which are toxic to insects but not to



mammals.  (See companion report on Pesticides.)



       The comparative toxicity of a number of organophosphorus



insecticides  is given in Table 5 in the Appendix.



       Experiments with mice exposed to inhalation of ethylo-



mercuric phosphate at concentrations equivalent to 0.03 to



0.04 iag/m3 of mercury was fatal to some mice after the 3rd



and 4th hour of exposure.  Concentrations of ethylomercuric



phosphate above 0.04 ug/m"3 killed the mice within 1 hour,



while 0.03 to 0.04 |jg/m3 of metallic mercury failed to cause



death of the experimental animals even after 8 hours exposure.



       Mice died 6 to 15 hours after exposure to ethylomercuric



phosphate vapor at concentrations equivalent to 0.006 to 0.009



|ag/m3 of mercury, while mice exposed to identical concentra-



tions of metallic mercury vapor did not die.    (See companion



report on Mercury-)



       Methyl phosphonic dichloride hydrolyzes rapidly



enough in the presence of moist air to produce fumes.  The



products of its hydrolysis are hydrogen chloride and

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                                                           15
methyl phosphonic acid  (CH3PO(OH)2),69  The vapors are



irritating to the skin, the mucous membranes, and the respira-

           26,28,51
tory tract„



       Experiments with rats which inhaled vapors of CH3POClo


for a 4-hour period at an average concentration of 360,000

    2

Hg/m  showed the following results.  During exposure the


animals were restless and nervous, and the skin around the


eyes was swollen with porphyrin secretions.  Breathing became


slow and difficult, necrosis was observed on paws and nostrils,


and the stomach was distended.  In addition to necrotic tissues,


there were hemorrhagic  edemata, areas of ulceration in the


stomach walls, hemorrhage in the pancreas and thymus, tubular


nephrosis, and excessive fat deposits in the liver, kidney,


heart, and skeletal muscles.  In rats exposed to ammonia-

                                                         o
neutralized CH POC1- at a concentration of 3,600,000 i-ig/m  ,
              J    ^

hemorrhagic edema was observed in the lungs, and death


                                     79           ...
occurred within a day after exposure.    Comparative toxici-


ties for experimental animals of certain phosphorus compounds


are presented in Table  6 in the Appendix.



2.3  Effects on Plants


       Phosphorus is an essential element of plant tissues,


but excessive concentrations produce adverse effects.  Most of


these types of effects result from antagonism among trace


elements.  The majority of the studies have been concerned with


excessive applications of phosphates in fertilizers.

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                                                           .re
       Heavy applications of phosphates can induce marked



deficiencies of trace elements—especially zinc and copper-



as shown in Table 1.






                           TABLE 1



      EFFECTS OF EXCESSIVE APPLICATION OF PHOSPHATE ON

                    SOUR-ORANGE SEEDLINGS6
Phosphate
(Ib/per acre)
0
76
360
900
1,800
Shoot Weight
(qrams)
31
34
26
22
14
Leaf Composition (ppm)
Copper
5.3
4.5
2.0
1.0
1.4
Zinc
28
30
20
21
12
       Phosphate-induced zinc deficiency is very common in



greenhouse crops, such as tomatoes.  It has also been demon-



strated that adding phosphates to the  soil where citrus



plants are grown results in decreased  absorption of boron,



copper, and zinc, even though the phosphates decrease the


        fi 7 TO "3^ 44
soil pH.   '-LW'-'-''rrrr  Moreover, the induced acute copper



deficiency is not influenced by the type of soil.  In acid



soils, the uptake of zinc and boron is usually retarded,



while in alkaline soils excess phosphate decreases molybdenum



uptake.  Application of heavy doses of superphosphate result


                                                58          35 40
in a marked decrease in the zinc content of oats   and flax.   '



Heavy applications of phosphate in certain soils may increase


                                                            69
the molybdenum content of the vegetation as much as tenfold.

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                                                           17
In some parts of Great Britain, where the copper dificiency


in cattle is largely induced by high levels of molybdenum in


the diet, excessive concentrations of phosphates in pastures


contribute to copper deficiency by both decreasing the avail-


able copper and increasing the molybdenum content of the grass,


       Even though the adverse effects of excess phosphates


are usually indirect, they are nevertheless serious enough to


be taken into account.  For example, phosphate-induced zinc


deficiencies are very extensive, being found in this country


in Wisconsin, throughout the Cotton Belt, and on the Pacific

      5,74,75
Coast.         The extent to which industrial sources of


phosphorus air pollution contribute to the excessive concen-


tration of phosphates in soils is not known.


       Two recent studies have shown that some phosphorylated


compounds—mainly sugar phosphates—inhibit carbon dioxide

                                       2
fixation by inert spinach chloroplasts,  and that addition of


phosphorus increases the severity of spinach injury produced

                                   Q
by fumigation with ozonated hexene.


       Studies of the effect of fluoride on the succinic


oxidase system in cauliflower mitochondria showed that in the


presence of phosphate, fluoride caused marked inhibition of


the succinic 2,6-dichlorophenolindophenol reductase.  It is


believed that this inhibition results from the formation of


an enzyme-fluorophosphate complex-  An oxidative phosphoryla-


tion were inhibited.  It has also been shown that concentra-

-------
                                                           18
tions of phosphate in plant tissue of 0.001 |ag and greater



definitely inhibit the acitivity of succinic dehydrogenase,



and that inhibition increases with higher concentrations.




2.4  Effects on Materials



       Very limited information has been found regarding



adverse effects of ambient air concentrations of phosphorus



and its compounds on materials.  It is known that phosphorus



pentabromide, pentachloride, and pentoxide, are corrosive, as


                              38
well as phosphorus tribromide.    Phosphoric acid (in solution)
is very corrosive to ordinary ferrous metals and alloys,


                                     n   54
particularly at temperatures above 85  C.    Wet phosphoric



acid is much more corrosive to metals than is phosphoric



acid made from elemental phosphorus because of the impurities



(including fluoride) contained in the wet-process acid.




2.5  Environmental Air Standards



       The threshold limit values adopted and recommended in



1967 by the American Conference of Governmental Industrial



Hygienists for phosphorus and some of its compounds are shown



in Table 2.



       The hygienic norms established in U.S.S.R. for ground-



level concentrations in the  ambient  air  of  phosphorus



pentoxide are as follows:



          Single maximum concentration:   150 t-ig/m



          Average 24-hour concentration:   50 |~ig/m

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                                                         19
                           TABLE 2
           THRESHOLD LIMIT VALUES FOR PHOSPHORUS
                   AND CERTAIN COMPOUNDS60
Substance
Threshold Limit Value
(PPm)
Phosdrin (Mevinphos)—skin*

Phosphine

Phosphoric acid

Phosphorus (yellow)

Phosphorus pentachloride

Phosphorus pentasulfide

Phosphorus trichloride
 0.3
 0.5
  100

  400

1,000

  100

1,000

1,000

3,000
       *Potential contribution to the overall exposure by
the cutaneous route, including mucous membranes and eye,
either by airborne or direct contact with the substance.

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                                                          20
SOURCES




3 .1  Natural Occurrence




       Natural phosphates are divided into three classes on



the basis of the metal or metals to which the phosphorus is



bound.  The three major classes are aluminum (iron)  phosphates,




calcium-aluminum (iron) phosphates, and calcium phosphates.




The last class is the most important one for the phosphate




fertilizer industry; its principal members are bone and apatite




found in phosphate rock.  Since the discovery in 1867 of de-




posits in South Carolina, phosphate rock has become increasingly




important and is now practically the only source of Phosphorus.




The average concentrations of phosphorus pentoxide (P_O5) were




estimated (1961) as 33.4 percent in phosphate rock from the




mines of Florida (land pebbles), 32.0 percent in that from




Tennessee, and 31.2 percent in phosphate rock from the




Western States.  The major constituents of phosphate rock are




P2O5  (27.5 to 33.0 percent); calcium oxide (41.9 to 46.1 per-




cent); volatile matter (1.9 to 7.0 percent); fluorine (2.9 to




4.4 percent); carbon dioxide; and oxides of silica,  iron,




aluminum, sulfur, potassium, and magnesium.




3.2  Production Sources     '




       The major portion of all phosphorus produced comes from




phosphate rock.  Domestic marketable production of phosphate




rock displays a very fast rate of growth, as shown in Table 7




and Figure 1, Appendix.  Starting with less than 2 million

-------
                                                          21
long tons in 1900, marketable production reached 4 million

tons in 1940, 10 million tons in 1950, approached 20 million

tons in 1960, and reached 35 million tons in 1966.  A total

of 100 million long tons of rock with a phosphorus pentoxide

^P2°5^ cont-ent of 16.43 percent was mined in 1966.

       In 1965, about 73 percent of the total domestic output

was produced in Florida, 10 percent in Tennessee, and most of

the remaining 17 percent in Idaho, Montana, Arkansas, Utah,

and Wyoming, in the order listed.  Florida's phosphate rock

contains from 20 to 35 percent phosphorus pentoxide.

       Most phosphate rock is used for the production of

fertilizers.  The distribution of phosphate rock sold or used

by producers during the period 1965-1967 was as follows:

                                  	Percent	
                                  19654q:  1966^  19674b

  Phosphoric acid (wet process)    21.0    28.5    41.0
  Triple superphosphate            21.5    27.6    16.0
  Electric furnace phosphorus      29.0    23.7    21.5
  Oridnary superphosphate          25.0    17.9    18.3
  Other (mostly for agriculture)    3.5     2.3     3.2

       Emission sources of particulates in storing and grinding

phosphate rock are shown in Figure 2 in the Appendix.

       Crude phosphates and phosphate fertilizers imported into

the United States represent less than 1 percent of the total

domestic consumption.  Thus in 1966, the imports of crude

phosphates amounted to 178 short tons or about 0.7 percent of

the domestic apparent consumption, while imports of phosphate

fertilizers and fertilizer materials amounted to 268 short

-------
                                                          22
tons.  Most of the small amounts of phosphate rock imported



is used as animal feed supplement because of the rock's low



fluorine content.45



       Elemental phosphorus is produced as a final product



for the chemical industry and as an intermediate product in



the production of phosphoric acid and fertilizers.



       Analysis of the flue dust samples obtained from the



phosphorus furnace operations of the Monsanto Chemical Company



(Monsanto, Tenn. ) showed that phosphorus pentoxide (P2C>5)  as



particulate constituted 18.89 percent of the flue dust.  Data



on gases evolved from the flue dust during heating showed



that phosphine and phosphorus pentoxide fumes (collected in



water) amount to 0.09 and 0.67 percent by weight of the total


       78
charge.    Flue dust is carried by the furnace gases along with



the vaporized elemental phophorus and is collected, while



hot, by an electrostatic precipitator before the gases reach



the phosphorus condenser.



       It should be noted that during the industrial produc-



tion of phosphorus,  it is possible that particles of elemental



phosphorus may be emitted.  Free phosphorus can exist in air



as a vapor because there are upper and lower limits on the



ratios in which oxygen and phosphorus react.  Consequently,



it cannot be assumed that all of the free phosphorus reacts

                                        f\ "7
to form phosphorus oxides and suboxides.

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                                                          23
3.3  Product Sources


3.3.1  Phosphoric Acids


        The types of phosphoric acids produced are ortho-  and


superphosphoric acids.   In the production of orthophosphoric


acid, the primary pollutant is phosphoric acid mist.   Emission


of P2°5 is ^n the range of °-3 to 5-° pounds per thousand

                                           2
pounds of elemental phosphorus (P4) burned.   Superphosphoric


acid (containing more than 70 percent P2°5^ i-s made bY


dehydrating wet-process acid or by burning elemental phosphorus


with air as in the furnace process, except that in the hydrator,


the cooling of the combustion gas is done with water or diluted


acid sprays.  About half of the P2C>5 drops out of the vessel


as superphosphoric acid, while the rest leaves as acid mist


at 200° F and is collected as less concentrated acid in an


electrostatic precipitator.  The diluted acid is sprayed back


into the hydrator, and the effluent gas from the precipitator


is vented to the stack.  Superphosphoric acid is also made


from the normal 50 to 55 percent acid.  The primary pollutant


is the phosphoric acid mist that is not removed by the mist


eliminator.  The quantity of acid mist can be assumed to be


about equal to or less than that vented in the furnace process


and  is related to the efficiency of the precipitator.  Pro-


ducing phosphoric acid from the wet-process acid  is carried


out  in a high vacuum, which tends to limit emissions.  More


information can be  found in reference 21.  In 1967 there were

-------
                                                          24
about 44 plants using the wet process and new plants are

being built.2'68'71

        Flow diagrams of processes used for the manufacture of

superphosphoric, wet-process phosphoric, and furnace phosphoric

acids are shown in Figures 3, 4, and 5 in the Appendix.

        Phosphoric acid ranked second in production value

(after ammonia) among the top 73 inorganic chemicals pro-

duced in 1965 and ninth in terms of production amount.9

Table 8 in the Appendix shows the growth of the phosphoric

acid industry in the United States.2

        The location of thermal process phosphoric acid

plants in the United States is given in Table 9 in the

Appendix.

        Phosphoric acids are used for the production of  ferti-

lizers, animal feed supplements (mono- and dibasic calcium

phosphates), and detergents (sodium and potassium polyphos-

phates).

3.3.2  Phosphate Fertilizers

        Phosphate fertilizers are produced from phosphoric

acid and phosphate rocks.

        The major types of phosphate fertilizers are:

                Diammonium phosphate
                Triple superphosphate
                Normal superphosphate
                Monoammonium phosphate
                Ammonium phosphate sulfate
                Ammonium phosphate nitrate
                Ammonium polyphosphates (solid and liquid)
                Nitric phosphates
                Other mixed fertilizers
                Phosphoric acid applied directly to soil

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                                                          25
In the above list, the first three fertilizers are the most



important in the order shown.  Diammonium phosphate production



(48 percent P2°5) has been replacing or reducing production



of triple superphosphate.  In 1965 there were about 48 plants



producing Diammonium phosphate.68  Emission points are shown



in Figure 6 in the Appendix.




        Triple superphosphate is produced in large plants near



phosphate rock deposits.  In 1965, there were 16 plants in



the United States producing 5.3 million tons per year.68



        Normal (ordinary) superphosphate fertilizers are pro-



duced by reacting sulfuric acid with phosphate rock.  In



1965 there were over 200 plants involved in this process, but



production is declining as more concentrated ^2^5 Pr°ducts



(triple superphosphate) are being produced.  The gases



released from acidulation of phosphate rock are the major



emissions.    Emission points are shown in Figure 7 in the



Appendix.



3.3.3 Phosphine



        Phosphine is an industrial hazard in (l) the manufac-



ture of acetyleine, where calcium phosphide is an impurity



in the calcium carbide used in the process, (2) phosphorus



extraction, (3) manufacturing of phosphorus sesquisulfide,



and (4) industrial operations with phosphorus-bearing ferro-



silicon.  Phosphine may, under low pH conditions, be evolved



from ferrophosphorus in the production of elemental phosphorus

-------
                                                          26
by the electric furnace process.  Phosphine is also generated



during the acid pickling of steel which contains small amounts



of iron phosphide.



3.4  Other Sources



3.4.1  Oil-Fired Boilers



        The fuel oil used most in boilers that produce steam



at a rate of 1,000 hp/hr (approximately 34,500 Ib/hr) or more



is designated as Bunker C, residual, high viscosity, heavy,



grade 6, or Pacific Standard 400.  Elemental analyses of



total particulates in the fly ash from the combustion of



residual oil showed in one test that phosphorus (as phosphorus



pentoxide) amounted to 0.9 percent of the total solids collected



in a laboratory electrical precipitator at 230° F.6^  In small



emission sources (less than 1,000 hp/hr), the fly ash loadings


                                  f\ ^
are higher than for large sources. 3



        The concentration of total phosphorus in the fly ash



from residual-oil-fired boilers has not been measured, nor



has the variation in phosphorus emission rates with respect



to the variation in other operating parameters been determined.



3.4.2  Iron and Steel Industry


                       64
        Schueneman et al. reported that phosphorus pentoxide



accounted for an average of 0.2 percent of the total weight of



fume produced during an entire melting cycle in an electric-



arc steel furnace.  In a 15-ton-arc steel furnace in which



dust collection of about 7 Ib/ton of melted steel was obtained,

-------
                                                          27
a typical analysis made in 1959 showed that the dust contained



0.4 percent phosphorus (as phosphorus pentoxide).16



        A typical analysis of the precipitator dust collected



during high-purity oxygen injection from an open-hearth steel



furnace (U.S. Steel Corporation, Allegheny County,  Pa.) showed



a phosphorus pentoxide content of 1.18 percent,63 while in



basic oxygen furnaces, chemical analysis showed that phosphorus



pentoxide amounted to 0.3 percent of the dust and fume.



        In a recent analysis of oxygen-lanced open-hearth



furnace fume, phosphorus pentoxide amounted to 0.5  percent.



        In a study-* of the efficiency of mineral wool filters



in collecting acid mists from open-hearth furnaces  and other



steel producing operations, the concentration of phosphoric



acid mist was found to range from 45,000 to 110,000 |jg/m3 .




3.4.3  Transportation Sources



        Many organophosphorus derivatives have been widely



used to reduce corrosion resulting from the combustion of



gasolines and aviation fuels.  Approved inhibitors  for avia-



tion fuels include alkylamiphosphate and 25 percent octyl



phosphate esters, and 25 percent octyl phosphate and 50 per-



cent ammonium alkyl phosphates for gasoline.  Ammonium alkyl



phosphate is also used an an anti-icing agent.  Concentrations



of these additives range from 5 to 20 pounds per 1,000 barrels



(2.3 to 9 grams per barrel) of aviation fuel.



        Phosphorus-containing additives (organophosphorus com-



pounds) are also used as modifiers of combustion chamber

-------
                                                          28
deposits resulting from surface ignition in motor gasolines,


as well as inhibitors of spark-plug fouling.  The list of


such phosphorus compounds commercially available for use in


gasoline includes tri-isopropyl phosphite, tri-cresyl phos-


phate, tri-chloropropyl thionophosphate, dimethyl xylyl


phosphate, dimethyl phenyl phosphate, trimethyl phosphate,


mixed cresyl phenyl phosphate, and alkyl aryl phosphate.


        It is possible that part of the phosphorus in fuel


additives is emitted into the ambient air as part of the


exhaust gases, and an investigation into this matter appears


to be desirable.


3.5  Environmental Air Concentrations


        The National Air Sampling Network has not been measuring


concentrations of phosphorus and its compounds in the ambient


air, and very limited data are available.


        Measurements of aerosol and vapor phase phosphates  in


the Los Angeles atmosphere (1954) indicated that concentration


values range from less than detectable limits to 4.23 i-ig/m3


(the average being 1.43 ng/m3).

                    q o
        Measurements   were made during the period February 14


to April 21, 1966 of air samples from Cincinnati and Fairfax


(a suburb of Cincinnati).  Single cascade impactors operated


for 24-hour periods were used to collect particulates for


colorimetric analysis, and both organic and inorganic phos-


phates in the form of orthophosphate were found.  The average


phosphate concentrations were 0.22 |_ig/m  in Cincinnati and

-------
                                                     29
0.31 p.g/m3 in Fairfax; the corresponding median particle dia-



meters were 2.7 and 3.9 ^ respectively.  The average particle-



size distribution curves for phosphates in Cincinnati and



Fairfax are shown in Figure 8 in the Appendix.  It can be



seen that while the median diameter is in the micron range,



about 20 percent of the total mass is in the submicron range.

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4.  ABATEMENT




           In the production of phosphoric acid by the thermal




    process, the major pollutant is phosphoric acid mist.  There




    are several pollution control devices used which are discussed



    below; one of the most important factors influencing emission




    rates is maintenance of the collection equipment.




           Scrubbers.  The use of packed and open tower scrubbers




    is a simple and low-cost abatement technique.  Collection



    efficiencies vary from 40 to 95 percent for gas velocities




    of 2 to 7 ft/sec.    Improved efficiency has been achieved by




    installing wire-mesh mist eliminators after the scrubber.




    Venturi scrubbers are also used and have higher collection




    efficiency, ranging from 78 to 98 percent for particle sizes




    of from 0.5 to 1 [a, respectively.




           Cyclones.  Cyclones have comparatively low collection




    efficiencies since they are effective only in the particle-




    size range of 10 |~i and above.  In some plants they are




    compelemented with wire-mesh mist eliminators or used in




    series with venturi scrubbers.   In this case a collection




    efficiency of up to 99.9 percent of the acid mist can be




    achieved.




           Fiber Mist Eliminators.   Plants using glass-fiber mist




    eliminators operating with gas  velocities ranging from 0.4 to




    13 ft/sec  provide collection efficiencies of 96 to 99.9 percent.




           High-Energy Wire-Mesh Contactors.   High-energy wire-




    mesh contactors can operate at  high vapor velocities of 20 to

-------
                                                           31
30 ft/sec and provide collection efficiencies that exceed

99.9 percent.70

       jElectrostatic Precipitators.  Electrostatic precipita-

tors show high collection efficiencies of 98 to 99 percent,

but also high maintenance costs.  The factors affecting their

performance are the rate of gas flow or temperature and the

electrical conditions during their operation.
                 24
       In a study   made by the International Minerals and

Chemicals Corporation, it was found that the optimum type of

equipment (in the farm chemicals industry) for the control of

phosphorus pentoxide (P2C>5) losses in the fumes is a modified

single-stage venturi scrubber followed by an impingement

basin.  The data reported on emissions from seven plants,

together with abatement devices used, are shown in Table 3.


                          TABLE 3

            EMISSIONS AND ABATEMENT DEVICES USED
            IN SEVEN PHOSPHATE FERTILIZER PLANTS24

Grade manufacturing: 5-10-10 to
10-20-10 production rate, tons/hr
Emission rates
Solids, Ib/hr
Fume , Ib/hr
Number of Cyclones*
Average
21
36
110
3
Range
15-32
13-138
31-241
2-4
       *Scrubbers used in five out of the seven plants in
conjunction with cyclones.

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                                                              32
5.   ECONOMICS


           In the production of phosphoric acid by the thermal


    process, capital cost of wire-mesh mist eliminators (a recent


    and effective abatement device) is reported to be approxi-


    mately $1.50/ft3/min of stack gas.11  Except for electrostatic


    precipitators, maintenance costs of collection equipment are


    not high.  When a continuous emission monitor is used, ex-


    cessive emissions can be easily detected.  Since the pollutant


    is also the final output (product) of the process, attempts

                                                                   2
    are usually made to minimize losses from the collection system.


           In the farm chemicals industry (phosphate fertilizers,


    insecticides, etc.) investment in pollution abatement equip-


    ment during the last few years have been quite large.  Most


    of this equipment is also used to reduce emissions of other


    pollutants, such as fluorine and ammonia.  For example, Agrico


    Chemical Company has added a large exhaust and scrubber system


    costing $581,000 to the control equipment at its phosphate


    complex in Pierce,  Fla.,  and about $400,000 worth of scrubber


    systems at several of its phosphate fertilizer plants in


    other areas.  Other companies have been spending comparable

                                                    24
    amounts for installation of abatement equipment.


           There have been large investments in the field of


    research and development as well as in monitoring systems.


    According to statistics by the Florida Phosphate Council,  the


    phosphate companies operating in the Polk-East Hillsborough


    area have spent $48 million to date in research, development,

-------
                                                           33
and installation of air pollution control systems for all air



pollutants.  Cost of operation and maintenance has been esti-



mated at more than $6 million annually.  Cost of installed



air pollution equipment varies from 20£ to $3.50 per cubic



foot per minute  (cfm).



       A study24 made by the International Minerals and



Chemicals Corporation showed that phosphorus pentoxide (P2°5)



losses varied from 3 to 53 Ib/hr.  The value of these losses



—including those of nitrogen and potassium—varies from $3.63



to $10.66/hr.


                            55
       It has been estimated   that by 1980, the U.S. electric



utility industry alone will produce some 45 million tons of



fly ash per year, containing 400,000 tons of phosphorus



pentoxide.  Utilized fly ash represents only 6 percent of the



current annual production, while the rest is dumped.



Disposal for this type of waste costs about $2 per ton and



creates a nuisance as well.

-------
                                                            34
METHODS OF ANALYSIS



6.1  Sampling  Methods



6.1.1  Free Phosphorus in Air



       One of  the problems in phosphorus determination is



separating free phosphorus from the many phosphorus compounds



found in the urban air.  A recently developed sampling method



draws air through a macro impinger containing 100 ml of



xylene at a rate of 1 cfm for 15 minutes.  A filter paper



attached to the exit catches any fumes which pass through the


  ,    60
xylene.



6.1.2  Phosphoric Acid (Plants, Stack Gases)



       Sampling of phosphoric acid mist in gas effluents from



stacks of phosphoric acid plants (thermal process) can be



done by a method based on that used by the U.S. Public Health



Service for particulate sampling.  The sampling train consists



of a probe, cyclone, filter, four impingers, pump, dry-gas


                                                              2
meter, calibrated orifice, and manometer, in the order listed.



The cyclone is designed so that particulate samples can be



separated into two fractions, one having particle diameters



less and the other having particles greater than 5 M.. The



first two impingers contain water, the third one  is dry, and



the fourth contains silica gel.  When phosphoric acid mist is



sampled/ the fritted-glass and paper filters are removed, so



that all particles passing through the cyclone are collected  in



the imp in ge r s.

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                                                          35
6.1.3  Phosphine



       In a spectrographic method developed recently for the



rapid determination of phosphine, air samples are collected



at the rate of 0.5 liter per minute (for about 10 minutes)  in



a fritted-glass bubbler.  The bubbler has a collection effi-



ciency of 86,2 percent at 0.5 liter per minute (75 percent  at



1 liter per minute) and contains silver diethyldiocarbamate.




6.2  Quantitative  Methods



6.2.1  Phosphorus  and Phosphoric Acid



       Phosphorus  is usually determined and estimated as



phosphoric acid expressed as phosphorus pentoxide (^2°5^ '



This determination may be done gravimetrically by forming a
magnesium pyrophosphate (Mg^P-Oy ) precipitate, titrimetrically,
                           £» £

                    27
or colorimetrically .


                                       32
       A number of colorimetric methods   are available, most



of which are based on the development of a blue color when



molybdate is treated with a reducing agent.  The ring-oven



colorimetric method66 uses as a reagent orthodianisidine molybdate



dissolved in glacial acetic acid which contains sodium molybdate.



The limit of identification is 0.002 tag and the range 0.05 to



2.0 |jg.



       The interference of phosphate in fluorimetric procedures



became the basis of various studies aimed at developing a



highly sensitive method of determining trace amounts of phos-



phate.32  One such method, based upon fluorescence quenching

-------
                                                           36
by phosphate of aluminium-morin chelate, permits the deter-



mination of 0.5 to 10 Lig of phosphate, or 0.5 to 0.1 |j.g/ml



in solution.  Ions of a number of elements, especially metals,



were found to interfere; and for the method to be specific,



phosphate is separated from such ions.32



       Recently, a method has been developed for the deter-



mination of free phosphorus and phosphorus vapor in air that



depends on trapping the element and its compounds in xylene.



Separation of phosphorus compounds from free phosphorus is



done by dissolving the compounds in water and separating the



phases, converting the free phosphorus to silver phosphide,



oxidizing the phosphide to phosphate, and estimating the phos-



phate by the molybdenum blue method.  Standards are prepared



in the range of 0 to 35 |ag of phosphorus, and the colorimetric


                                                           60
portion of the procedure is carried out with each standard.



       Determination of phosphorus in phosphoric acid emitted



from stacks of phosphoric acid plants can be made with the



ammonium phosphomolybdate colorimetric method, which is based



on the spectrophotometric determination of the yellow



ammonium phosphomolybdovanadate complex formed when ortho-



phosphate reacts with the reagent in an acid medium.  The



method is applicable to materials in which phosphorus com-



pounds can be quantitatively oxidized to the orthophosphate


     9 9 59 73
form.     '    Interference comes from (1) certain ions which



reduce the color to molybdenum blue, (2) oxalates, tatrates,

-------
                                                          37
and citrates which  tend  to bleach  the color,  (3) high concen-



trations  of iron  and  (4)  of  dichromate, resulting from the



close resemblance of  the  color  of  the dichromate ion to the



yellow complex  ammonium  phosphomolybdovanadate.  This method



is applicable to  the  determination of total phosphates in the



concentration range of about 50 |_ig to 2,000 |Jg, with a repli-



cation precision  of - 1.0 percent.    Another method used



for the determination of  phosphoric acid  in stack gas samples



is acid-base titration.




6.2.2  Phosphine



       Phosphine  in air  can  be  determined by colorimetric


                                          13
methods.   Recently  a  spectrographic method   has been developed



for the rapid determination  of  phosphine  in the range of 0.1



to 1 ppm.  The  method uses silver  diethyldiocarbamate as



reagent and depends on the formation of a complex of phos-



phine and the reagent with an absorption  maximum at 465 m|a.



It is necessary to  calibrate the procedure by a second method



analyzing phosphine as phosphate,  since no primary phosphine



standards  are presently  available.




6.2.3  Organophosphorus Pesticides



       For the  detection  of  organophosphorus pesticides, gas



chromatography  has  been used in conjunction with a flame-


            39            25
photometric,    thermionic,    or electron-capture detector.  See



companion  report  on pesticides  for more details on analytical



methods of organophosphorus  pesticides.

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                                                              38
7.  SUMMARY AND CONCLUSIONS




           Some forms of phosphorus are toxic to humans and



    animals.  Yellow phosphorus is a protoplasmic poison, while



    red phosphorus is comparitively nontoxic.  Some of the phos-



    phorus inorganic compounds, such as phosphine gas, are highly



    toxic at concentrations of 400 to 600 ppm, while others—such



    as tricalcium phosphate—are only mildly so.  Many of the



    organic compounds of phosphorus are extremely toxic.  However,



    very few of the known phosphorus compounds have been investi-



    gated with respect to their toxic effects on humans, animals,



    and plants.



           The effect of some phosphorus compounds is the inhibi-



    tion of cholinesterase, a process which is slow and sometimes



    cumulative and irreversible.  The nervous system is affected



    by this type of adverse action.  Nevertheless, the potential



    hazard represented by the ambient air concentrations of phos-



    phorus and its compounds is unknown.



           The source of almost all phosphorus and phosphorus



    products is phosphate rock.  The major uses of phosphorus com-



    pounds are the manufacturing of fertilizers, pesticides, and



    industrial chemicals.   These processes are the major sources



    of phosphorus emissions in the ambient air.  Boilers and



    furnaces burning some crude oils and coals which contain phos-



    phorus represent secondary emission sources of phosphorus com-



    pounds.  The production of phosphorus and its primary products

-------
                                                          39
has been increasing annually.  Production of phosphate rock




in 1966 was more than three times the 1950 level (approximately




100 million long tons), while the production of phosphoric acid




shows the highest rate of increase among major industrial acids.




        No national data exist on the ambient air concentrations



of phosphorus.  The few local data available from special




studies indicate an average ambient air concentration, in



1954, of 1.43 Lig/m3.




        Abatement of phosphorus emissions includes the use of




scrubbers, fiber mist eliminators, high-energy wire-mesh con-




tactors, and electrostatic precipitators.




        No information has been found on economic costs of




phosphorus air pollution.  Investment in air pollution control




equipment within the phosphate industry has been relatively



high, especially in Florida, where the phosphate fertilizer




industry is concentrated.  Operating costs of control equip-




ment in this section of the fertilizer industry have been




estimated at $6 million annually; this also includes the




control of fluoride emissions.



        The quantitative determination of phosphorus and its



compounds in the environmental air is made by colorimetric



and spectrographic mathods.  The most frequently used is the




molybdenum blue method (colorimetric).  Specific methods have




been or are being developed for the determination of elemental




phosphorus, phosphoric acid, phosphine, and organophosphorus

-------
pesticides.  Maximum sensitivities are in the microgram level



or below.



        Based on the material presented in this report, further



studies are suggested in the following areas:



        (1)  Determination of the long-term exposure effects



on man, animals, and plants of phosphorus and its inorganic



and organic compounds.



        (2)  Determination of the concentration of phosphorus



in the ambient air, by type of compounds wherever feasible,



in the stations monitored by the National Air Sampling Network.



        (3)  Evaluation of the pollution contribution by



phosphorus from selected stationary emission sources,



particularly significant local sources, such as the fertilizer



industry.



        (4)  Evaluation of the pollution contribution by



phosphorus compounds emitted from transportation sources.

-------
                                                            41
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 2.  Atmospheric Emissions from  Thermal-Process  Phosphoric
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 3.  Bamberger, E.  S. , et  ail. , Effect of Phosphorylated Com-
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 4.  Bear, F. E., Trace Elements—Progress  Report on Research,
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 5.  Billings, C. E. , _et ai_. , Simultaneous  Removal of  Acid
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 6.  Bingham, F. T. , et_ al_. , Effect of Phosphorus Fertiliza-
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 7.  Bingham, F. T., et al., Solubility  and Availability  of
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 8.  Brewer, R. F. , _et_ aJL.. , Influence of N-P-K Fertilization
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 9.  Chemical Origins and  Markets,  Stanford Research Institute,
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10.  Chester, C. G. C. , et .al.. ,  The Role of Zinc in Plant Meta-
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12.  Dathe, R. A., _et al., Electrocardiographic  Changes
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13.  Dechant, R. , et a.1. ,  Determination  of  Phosphine in Air,
     Am. Ind. Hyg.  Assoc.  J. .27:75  (1966).

14.  Diaz-Rivera, R. S. , et aj... , Acute Phosphorus Poisoning
     in Man:  A Study of 50 Cases, Medicine 2_9:269 (1950).

-------
                                                          42
15.  Diaz-Rivera, R.  S.,  et  al., The Electrocardiographic
     Changes in Acute Phosphorus Poisoning in Man, Am. J.
     Med. Sci. 241:758  (1961).

16.  Douglas, I. H. ,  Direct  Fume Extraction and Collection
     Applied to a Fifteen Ton Arc Furnace, Iron and Steel
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17.  DuBois, K. P., _et .al. ,  Influence of Induction of Hepatic
     Microsomal Enzymes by Phenobarbital on Toxicity of Organic
     Phosphate Insecticides, Proc. Soc. Exptl. Biol. Med. 129;
     699  (1968).

18.  Einbrodt, H. J. , est.  al,. , Die chemische Zusammensetzung
     der  in den Lungen und regionaren Lymphknoten abgelagerten
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19.  Fedor, W. S. ,  Inorganics Hold Rapid Pace, Chem. Eng. News
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20.  Fedor, W. S. ,  Inorganics Steady in a Slowdown, Chem. Enq.
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21.  Gandevia, B. , _e_t .§_!„ , Relevance of Respiratory Symptoms
     and  Signs to Ventilatory Capacity Changes After Exposure
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22.  Guinland, K. P., &t jJ., Spectrophotometric Determination
     of Phosphorus  as Molybdovanadophosphoric Acid, Anal. Chem.
     21:1626 (1955).

23.  Henderson, Y., et al.,  Noxious Gases and the Principles
     of Perspiration  (New York:  Reinhold, 1943)0

24.  Industry Answers the Challenge, Farm Chem. pp. 21, 24,
     26, 28 (June 1967).

25.  Ives, N. F., et..  al.. , Pesticide Residues, Investigation
     of Thermionic Detector  Response for the Gas Chromato-
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     Off. Analvt. Chem. J50(l):l (1967).

26.  Jacobs, M. B., The Analytical Chemistry of Industrial
     Poisons, Hazards, and Solvents (New York:  Interscience,
     1949).

27.  Jacobs, M. B., The Analytical Toxicology of Industrial
     Inorganic Poisons (New York:  Interscience, 1967).

-------
                                                           43
28.  Jacobson, K. H., The Acute Toxicities of Some Intermediates
     in GB Manufacture, Report No. 17, Army Chemical Center, Md.
     (1953).

29.  Kloos, E. J., Gas Masks for Respiratory Protection Against
     Phosphine, U.S. Government Printing Office (1966).

30.  Kopcznski, W. , et al^. , Mental and Sexual Disorders as a
     Sequela of Tricresyl Orthophosphate Poisoning, Psychiatria
     Pol ska 1(3);267 (1967).

31.  Kosalapoff, G. M. , Organosphosphorus Compounds (New York:
     Wiley, 1950).

32.  Land, D. B., _et aJL.. , A Fluoremetric Method for Determining
     Trace Quantities of Phosphate, Mikrochim. Acta (Vienna)
     6.:1013 (1966).

33.  Lee, R. E. , et_ ai_. , Size Determination of Atmospheric Phos-
     phate, Nitrate, Chloride, and Ammonium Particulate in
     Several Urban Areas, U.S. Dept. of Health, Education, and
     Welfare, Public Health Service, Cincinnati, Ohio (1968).

34.  Lodwick, J. R. , Chemical Additives in Petroleum Fuels:
     Some Uses and Action Mechanisms, Inst. Petrol. J. 50(491) :
     297 (1964).
35.  Loneragen, J. F., The Effect of Applied Phosphate on the
     Uptake of Zinc by Flax, Australian J. Sci. Res. Ser. B. _4:
     108 (1951).

36.  Lovelace, C. J., et al., In Vitro Effects of Fluoride on
     Tricarboxylic Acid Cycle Dehydrogenases and Oxidative Phos-
     phorylation:  Part I., J. Histochem. Cyctochem. 15(4) :195
     (1967).

37.  Mackworth, _et a.1.. , Biochem. J. .421:91 (1948).

38.  The Merck Index, 8th ed. (Rahway, N.J.:  Merck, 1968).

39.  Midwest Research Institute for Division of Pesticides, U.S.
     Food and Drug Administration (Report to be published).

40.  Millikan, C. R., Effects of Phosphates on the Development
     of Zinc Deficiency Symptoms in Flax, J. Dept. Agr. Victoria
     _45_:273 (1947).

41.  Minerals Yearbook, Bureau of Mines, U.S. Govt. Printing
     Office, Washington, D.C. (1950).

42.  Minerals Yearbook, Bureau of Mines, U.S. Govt. Printing
     Office, Washington, D.C. (1955).

-------
                                                            44
43•   Minerals Yearbook. Bureau of Mines, U.S. Govt. Printing
     Office, Washington, D.C. (1960).

44.   Minerals Yearbook. Bureau of Mines, U.S. Govt. Printing
     Office, Washington, D.C. (1965).

45.   Minerals Yearbook. Bureau of Mines, U.S. Govt. Printing
     Office, Washington, D.C. (1966).

46.   Minerals Yearbook. Bureau of Mines, U.S. Govt. Printing
     Office, Washington, D.C. (1967).

47.   Moeschlin, S. , Poisoning, Diagnosis, and Treatment (New
     York:  Grune & Stratton, 1965).

48.   Nachmansohn, D., Chemical Factors Affecting the Physiology
     and Pathology of Nervous Function, Contract DA/49/007/MD/740,
     Armed Forces Technical Information Agency, Arlington,  Va.
     (1959).

49.   Neiburger, M. , "Meteorological Aspects of Oxidation Type
     Air Pollution," in The Rossby Memorial Volume (New York:
     The Rockefeller Institute Press in assoc. with Oxford Univ.
     Press, p. 158, 1959).

50.   Newburger, R. A., _et a_l_., Phosphorus Poisoning with Recovery
     Accompanied by Electrocardiographic Changes, Am. J. Med.,
     1:927 (1948).

51.   Oettengen, W. F. von, Poisoning:  A Guide to Clinical Diag-
     nosis and Treatment (Philadelphia:  Saunders, 1958).

52.   Patty, F. A. (Ed.), Industrial Hygiene and Toxicology,
     vol. II (New York:  Interscience, 1949).

53.   Pietras, R. J. , et aJL. , Phosphorus Poisoning Simulating
     Acute Myocardial Infarction, Arch. Internal Med. 122:430 (1968)

54.   Properties and Essential Information for Safe Handling and
     Use of Phosphoric Acid, Chemical Safety Data Sheet SD-70,
     Manufacturing Chemists Association, Washington, D.C. (1958).

55.   Pursglove, J., Jr., Fly Ash in 1980, Coal Age, pp. 84-85
     (Aug. 1957).

56.   Reimann, H. A., _et a^. , Tricalcium Phosphate Crystallosis,
     J. Am. Med. Assoc. 189 :195 (1964).

57.   Reimann, H. A., et_ a±. , Experimental Tricalcium Phosphate
     Crystallosis, Arch. Environ. Health 10:33 (1965).

-------
                                                           45
58.  Rogers, L. H. , .et al_. , Zinc Uptake by Oats as Influenced by
     Applications of Lime and Phosphate, J. Am. Soc. Agron. 40:
     563 (1948).

59.  Rogers, R. N., Determination of Phosphate by Differential
     Spectrophotometry, Anal. Chem, .32:1050 (1960).

60.  Rushing, D. E., A Tentative Method for the Determination of
     Elemental Phosphorus in Air, U.S. Dept. of Health, Education,
     and Welfare, Public Health Service, Salt Lake City, Utah (1968)

61.  Ryazanov, V. A. (Ed.), Limits of Allowable Concentrations
     of Air Pollutants, Translated from the Russian by B. S.
     Levine, Book 2 (1955), Clearinghouse for Federal Scientific
     and Technical Information, Springfield, Va.

62.  Sassi, C., Occupational Poisoning due to Phosphorus Tri-
     chloride, J. AMA Ind. Hyg. & Occ. Med. .7:178 (1953).

63.  Schneider, R. L., Engineering, Operation and Maintenance
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64.  Schueneman, J. J. , j2t ai_. , Air Pollution Aspects of the
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65.  Smith, W. S. , Atmospheric Emissions from Fuel Oil Consump-
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66.  Stern, A. C. (Ed.), Air Pollution, vol I  (New York:  Aca-
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67.  Stern, A. C. (Ed.), Air Pollution, vol. II (New York:
     Academic Press, 1968).

68.  Stern, A. C. (Ed.), Air Pollution, vol. Ill  (New York:
     Academic Press, 1968).

69.  Stout, P. R., .et a_l. , Molybdenum Nutrition of Crop Plants,
     Plant Soil 3:51 (1951).

70.  Striplin, M. M. , Development of Processes and Equipment
     for Production of Phosphoric Acid, Chemical Engineering
     Report No. 2, Tennessee Valley Authority  (1948).

71.  Superphosphate:  Its History, Chemistry, and Manufacture,
     U.S. Dept. of Agriculture, U.S. Govt. Printing Office,
     Washington, D.C. (Dec. 1964).

-------
                                                           46
72.  Tabershaw, I. R., _et a^l. , Sequelae of Acute Organic Phos-
     phate poisoning, J. Occupational Med. J3( 1) : 5 (1966).

73.  Talvitic, N. A., _e_t aj^. , Spectrophotometric Determination
     of Phosphorus as Molybdovanadophosphorus Acid, Application
     to Airborne Particulate Matter, Anal. Chem. _3_4:866  (1962).

74.  Thaker, E. J., _et a^. , Occurrence of Mineral Deficiencies
     and Toxicities, Soil Sci. 8J5(ii):87  (1958).

75.  Thomson, L. M. , Soil and Soil Fertility (New York:  McGraw-
     Hill, 1952).

76.  Threshold Limit Values for 1967, Adopted at the 29th Annual
     Meeting of the American Conference of Governmental  Indus-
     trial Governmental Hygienists, Chicago, 111. (May 1-2, 1967).

77.  Trakhtenberg, I. M. , The Toxicity of Vapors of Organic
     Mercury Compounds (Ethylmercurie Phosphate and Ethylmercuric
     Chloride) in Acute and Chronic Intoxication, Survey of
     U.S.S.R. Literature on Air Pollution and Related Occupational
     Diseases 3:205  (1960).

78.  Waters, R. F., _et aJ^. , Extraction of Germanium and  Gallium
     from Coal Fly Ash and Phosphorus Furnace Flue Dust, Bureau
     of Mines, Report No. 6940 (Apr. 1967).

79.  Weeks, M. H. , .et al., Acute Vapor Toxicity of Phosphorus
     Oxychloride, Phosphorus Trichloride, and Methyl Phosphonic
     Dichloride, Am. Ind. Hyg. Assoc. J.  25_(5):470 (1964).

-------
                                                          47
OTHER REFERENCES

Coykendall, J. W. , et al. , New High-Efficiency Mist Collec-
tor* J. Air Pollution Control Assoc. 18.(5):315 (1968).

Diem, K.  (Ed.), Documenta Geigy, Scientific Tables, 6th ed.
(Adsley, N.Y.:  Geigy Chemical Corp., 1962),

Jewell, J. P., Control of Fluoride Emissions, Proceedings
of 5th Annual Sanitary and Water Resources Engineering Con-
ference, Nashville, Tenn., p. 226  (June 1965).

Mayer, M. , A  Compilation of Air Pollutant Emission Factors
for Combustion Processes, Gasoline Evaporation, and Selected
Industrial Processes, Technical Assistance Branch, Division
of Air Pollution, U.S. Dept. of Health, Education, and Wel-
fare, Public Health Service, Cincinnati, Ohio (May 1965).

Schutte, K. H., The Biology of Trace Elements (Philadelphia:
Lippincott, 1964).

Senchuk, V. S., The Effect of Atmospheric Ultraviolet Radia-
tion Insufficiency on Mineral Metabolism, USSR Literature on
Air Pollution and Related Occupational Diseases lilll (1960).

Teller, A. J., Control of Gaseous Fluoride Emissions, Chem.
Eng. Progr. _63_(3):75  (1967).

Weinstein, L. H., et al., Automated Analysis of Phosphorus-
Containing Compounds in Biological Materials. I.  A Quantita-
tive Procedure, Contrib. Boyce Thompson Ins^0 22_(1):389  (1964).

Weinstein, L. H. , &t jJL. , Automated Analysis of Phosphorus-
Containing Compounds in Biological Materials. II.  Acid-
Soluble Nucleotides, Short Communications, Anal. Biochem. 2.
(1):155  (1965).

Wett, T. W. (Ed.), Competitors Collaborate to Choke Off Air
Pollution, Chem. Processing 31(1):27  (1968).

Woltz, S. S., Distinctive Effects of Root Versus Leaf Acquired
Fluorides, Proc. of Florida State Horticultural Society  (Miami,
Fla.) 77:516  (1964).

-------
APPENDIX

-------
                                                                       49
Long Tons


 X  106
                                                          '            (2)
                                                          /  Consumption
    1900
1910
1920
1930
1940
1950
    c
1960 1965
                                                                    1980
    (1) Marketed production  (sold or used)

    (2) Apparent consumption (=production + imports-exports)
                                   FIGURE  1




            Marketed Production, Apparent Consumption,  and


              Exports of  Phosphate  Rock,  igoO-GG^1"45-71

-------
Wet

Phosphate

Rock
                            Exit (Particulate SO2]
Dryer
Storage Silo
                                                                 Exit  (Particulate)
Grinding Mill
Phosphate Rock
   Dust Silo
                                                                                                           Exit  (Particulate)
Storage Bins
                     Fuel Natural Gas or Fuel Oil
                                                        FIGURE  2
                     Flow  Diagram  of Phosphate  Rock  Storage  and Grinding Facilities
                                                                                                  68
                                                                                                           Ul
                                                                                                           o

-------
                  Liquid Phosphorus
St63rn
^
Phosphorus Tank
                           Cooling
                           Water
                           Water
                                 ->
                              CD
                              -O
                              C
                              o
                              u
u
CO
C
P205
                                                Acid Mist Vent 'Gas
o

CO

•O
                                                           Dilute Acid
                                                         <-
                                                           Water
                                                     Recycle Superacid
                                                       76% P2O5
                                                                 -^
                                                                                           Exjt^

                                                                                 •Exhaust Gases, Acid Mist
                                                                            Precipitator
                                                                                Agitated
                                                                              Cooling Tank
                                                                                A
                                                                               CD
                                                                                    V
                                                                                             Storage
                                                                                                                       en
                                                FIGURE 3


              Flow Diagram of  Process  for Production of  Superphosphoric Acid
                                                                                     68

-------
Sulfuric Acid
           W
              Reactor
Phosphate Rock
          Exit
Si F- and HF to Wet Scrubber
          A
                              Weak Acid
            Recycle
         Filter
                                      V
                                                  -^
                                                                A
30-32% P^05
Acid  Storage
                                 Gypsum to Waste
                                                                                   Water
                                                                                              Exit to
                                                                             Condenser
                                                                                A
                                                                                         Vacuum Source
                                                                                            (Fluorides)
                                                          Hj2SiF6 to Recovery
                                                                                           or Waste
                                                                                                          ->
 Vacuum
Evaporator
                                                     v
                                                  Product
                                                54% RO  Acid
                                                     2 o
                                               FIGURE  4
                     Flow Diagram of  Wet  Process  Phosphoric Acid Plant
                                                                                 68
                                                                                                                    ui

-------
                                       Dilute Phosphoric Acid
                                                         Water
Phosphorus
Air
Combustion
 Chamber
                              V
Hydration
 Tower
Absorber
 Tower
                                                                   o
                                                                                       TO
                                                                                      >
                                                                                       i-
                                                                                       CD
                                                                             NaHS
                                                                                  Treating
                                                                               Raw Acid
                                                                                             To Spray Chamber
                                                                                             Demister or Venturi
                                                                                             Collector
                                                                                          HS
                                                                               To Storage
                                                                                              Food Grade
                                                                                              phosphoric Acid
                                                   FIGURE 5

                            Flow Diagram  of Furnace  Phosphoric Acid Plant
                                                                 68
                                                                                                      u-
                                                                                                      u;

-------
  Exit
(Fluoride)
          Exit
(Ammonia, Fluoride & Particulate)


Phosphoric Acid







Phosphate Rock



•^


\



f





Mixer
/

\

/


\







"^^






Belt Den










X
s


/\ '
Exit
(Fluoride) (Particulate and Fluoride)
/



\ A
NH
3
V
Granulated
Curing

S

Product

/ Run of Pile Product
                                                  Exit
Exit (Fluoride)^
Phosphoric Acid ^
Phosphate Roc
s
\
t

Mixer
/
k
\
1

\
•^




Blunger

N

/
Dr
(Particulate, Fluoride & Sulfur Oxide) ^
Exit (Particulate)
A >
Granulated Product
vpr . T Sprr*pn _ ^


                          FIGURE  6
          Flow Diagram: Production of  Run of Pi
            and Granular Triple Superphosphate

-------
Gaseous Fluoride Particulate and
Sulfur Dioxide
                  Exit (Gaseous Fluoride)
                                       (Ammonia Particulate) Exit
                                                        (Ammonia Particulate)
                                                        Exit  (Gaseous Fluoride)
                                Ammoniator
                                Granulator
                       Run of Pile Product
                                  Grinding
                                                                                 (Particulate)  Exit
                                                                 Bagging Product
                                                                                        •a
                                                                                         CD
                                                                                         D
                                                                                         C
                                                                                         2
                                                                                       i O
                               FIGURE  7

        Flow Diagram  of Normal  Superphosphate  Plant"
68
                                      Ul
                                      Ul

-------
                                                                 56
o
u
1
   6.0

   5.0


   4.0



   3.0



   2.0
U

t
fO
Q-
1.0
0.9

0.8
0.7

0.6

0.5


0.4



0.3
   0.2   -
   0.1
                   Fairfax
                        o-
                                 Cincinnati
                          J	L
                              _L
                                                      J	L
0.01   0.05   0.2  0.5 1   2    5    10

                    % Mass ^  Diameter
                                              20  30  40 50
                              FIGURE  8


           Cumulative  Particle Size Distribution of
          Phosphate  in Cincinnati  and Fairfax,

-------
                                    TABLE 4




PROPERTIES, TOXICITY, AND USES OF PHOSPHORUS AND SOME PHOSPHORUS  COMPOUNDS38
Compound
Phosphorus
P




















Pho sphamidon
C10H19C1N05P
Properties
White phospho-
rus: colorless
or yellowish
cry-s trail ine
solid
mp 44.1°
bp 280°
volatile
Black phospho-
rus: crystals
Red phosplio-
rus t red to
violet powder
Sublimes at
416°







Oil
bp 162°
Toxic itv
White phosphorus: inges-
tion of even small amounts
may produce severe gastro-
intestinal irritation,
bloody diarrhea, liver
damage, skin eruptions,
oliguria, circulatory
collapse, coma, convul-
sions, death. The approx-
imate fatal dose of
white (also called yellow)
phosphorus is 50 mg. Ex-
ternal contact may cause
severe burns. Chronic
poisoning (from ingestion
or inhalation) produces
spontaneous fractures,
anemia, weight loss
Red phosphorus is rela-
tively nontoxic unless it
contains the white form as
an impurity
Cholinesterase inhibitor

Uses
Red phosphorus: in pyro-
technics, manufacture of
safety matches, organic syn-
thesis; in manufacture of
phosphoric acid, phosphine
phosphoric anhydride, phos-
phorus pen ta chloride, phos-
phorus trichloride; in manu-
facture of fertilizers, pes-
ticides, incendiary shells,
smoke bombs, tracer bullets.
Med. use: formerly in
rickets, other bone diseases,
and degenerative disorders
of central nervous system







Systemic insecticide

                                                                             (continued)
                                                                                            en

-------
   APPENDIX
                                      TABLE 4  (Continued)

         PROPERTIES, TOXICITY, AND USES OF PHOSPHORUS AND SOME PHOSPHORUS  COMPOUNDS
Compound
  Properties
        Toxicitv
             Uses
Phosphine
PH.,
Gas
Odor of decay-
ing fish
bp -87.7°
mp -133°
Inhalation causes pain in
region of diaphragm, a
feeling of coldness, ver-
tigo, dyspnea, bronchitis,
edema, lung damage, con-
vulsions, coma, death.
Lethal dose for rats in
air, 60 ppm
Phosphocreatine
C4H10N305P
                                             Med. use:  In sodium salt to
                                             treat fatigue.
Pho s phomo1ybdi c
  acid
20Mo 3•2H3-

P04-48H20
Bright yellow
crystals
                            In weighting silks; as rea-
                            gent for alkaloids, uric
                            acid, xanthine, creatinine,
                            some metals, with hema-
                            toxylin as nerve stain in
                            microscopy
Phosphonium
  iodide
PH4I
Large trans-
parent color-
less crystals
Readily liberates phos-
phine, which is highly
toxic, and hydriodic acid,
which is a strong irritant
In laboratory preparation of
phosphine
                                                                                     (continued)
                                                                                                   Ul
                                                                                                   CO

-------
    APPENDIX
                                      TABLE 4 (Continued)

         PROPERTIES, TOXICITY, AND USES OF PHOSPHORUS AND SOME PHOSPHORUS COMPOUNDS
Compound
 Properties
         Toxicity
             Uses
Phosphoric acid
H3P04
Unstable
orthorhombic
crystals
mp 42.35°
Concentrated solutions are
irritating to the skin and
mucous membranes
In the manufacture of super-
phosphates for fertilizers,
other phosphate salts, poly-
phosphates, detergents; as
acid catalyst in making
ethylene, purifying hydrogen
peroxide; as acidulant and
flavor in beverages of the
soft drink type; in dental
cements; in process engraving
in rustproofing of metals be-
fore painting; in coagulating
rubber latex;  as analytical
reagent.
Med. use:  has been used
(dilute form)  as gastric and
urinary acidifier; as dress-
ing for removal of necrotic
debris of burns.  Vet. use:
diluted phosphoric acid has
been used in treating lead
poisoning
Phosphoric acid
(HP03)n
Colorless,
transparent,
glass-like
solid
                            In dentistry for making zinc
                            oxyphosphate cement;  as
                            reagent in chemical analysis
Phosphorous acid
H3P03
White crystalline
mass, garlic-
like taste
                                                                                     (continued)

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                                      I1 ABLE 4 (Continued)

         PROPERTIES, TOXICITY, AND USES OF PHOSPHORUS AND SOME PHOSPHORUS COMPOUNDS
Compound
  Properties
         fToxicity
             Uses
Phosphorus
  hemitriselenide
Dark red mass
Decomposes by
heat
Phosphorus
  oxybromide
POBr0
Thin plates
Faintly orange
mp 56°
bp 193°
Phosphorus
  oxychloride
POC10
Colorless,
clear liquid
bp 107°
Intensely irritating to
eyes, skin, mucous mem-
branes.  Inhalation may
cause pulmonary edema
As chlorinating agent, espe-
cially to replace oxygen in
organic compounds; as solvent
in cryoscopy
Phosphorus
  pentabromide
PBrc
Yellow cry-
stalline mass
mp above 100°
Toxic and corrosive
Phosphorus
  pentachloride
PC1C
White to pale
yellow
mp 148°
bp 160°
Toxic and corrosive
As catalyst in manufacture of
acetylcellulose; for replac-
ing hydroxyl groups by Cl,
particularly in converting
acids into acid chlorides
Phosphorus
  pentafluoride
Colorless gas
mp -93.8°
bp -84.6°
Intensely irritating to
skin,  eyes,  mucous mem-
branes .  Inhalation may
cause pulmonary edema
                                                                                     (continued)

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     APPENDIX
                                       TABLE  4 (Continued)

         PROPERTIES, TOXICITY, AND USES OP PHOSPHORUS AND SOME PHOSPHORUS COMPOUNDS
Compound
  Properties
          Toxicity
             Uses
Phosphorus penta-
  selenide
P2Se5
Black needles
Decomposes in
steam and boil-
ing water
Phosphorus
  pentasulfide
P2S5
Light yellow
crystalline
mass
mp 280°
bp 523°
On contact with water, de-
composes to form hydrogen
sulfide.  In air, forms
phosphorus pentoxide,
which is a strong irritant
In manufacturing safety
matches, ignition compounds,
and for introducing sulfur
into organic compounds
Phosphorus pentoxide
P2°5
Very deliques-
cent crystals
mp 580-585°
Strong irritant, corrosive
As drying and dehydrating
agent, condensing agent in
organic synthesis
Phosphorus
  sulfochloride
PSC13
Fuming liquid
bp 125°
Strong irritant
Phosphorus
  tribromide
Colorless
liquid
bp 175°
Toxic and corrosive
Phosphorus
  trichloride
Colorless
liquid
mp -112°
bp 76°
Highly irritating and
corrosive to skin, mucous
membranes
Same uses as phosphorus oxy-
chloride; in manufacturing of
POClg, PClg, and in producing
iridescent metallic deposits
                                                                                    (continued)

-------
APPENDIX
                                   TABLE 4 (Continued)
     PROPERTIES, TOXICITY,  AND USES OF PHOSPHORUS AND SOME PHOSPHORUS COMPOUNDS
Compound
Phosphorus
trif luoride
PF3
Phosphorus
trioxide
P2°3
Phosphorus
triselenide
P4Se3
Phosphorylcholine
JTCH3)3 *NCH2-
CH2OP03-
H2C1
Phosphotungstic
acid
24W03'2H3-
P04 • 48H20
Properti es
Colorless gas
mp -151.5°
bp -101.8°
Transparent
monoclinic
crystals
mp 23.8°
bp 173.1°
Orange-red
crystals
mp 242°
bp 360-400°

White or
slightly
yellow- green
Toxic itv
Intensely irritating to
skin, eyes, mucous mem-
branes. Inhalation may
cause pulmonary edema




Uses



Med. use: As the magnesium
salt in hepatobiliary
dysfunction
As reagent for alkaloids and
many other nitrogen bases,
phenols, albumin, peptone,
aminoacids, uric acids, urea,
blood, carbohydrates
                                                                                  (continued)

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                                       TABLE 4  (Continued)

           PROPERTIES, TOXICITY, AND USES OP PHOSPHORUS AND SOME PHOSPHORUS COMPOUNDS
Compound
 Properties
          Toxicity
            Uses
S'-Adenylic acid
  (Phosaden)
C10H14N5°7P
mp 196-2000
                            Med. use:  adenyl compounds
                            have been reported to produce
                            coronary dilation, bradycar-
                            dia, hypotension, leukocyto-
                            sis
Phosdrin
Yellow liquid
mixture
bp 106-107.5°
Cholinesterase inhibitor
   g orally in mice:
     9.0 mg/kg; in rats
     4.0 mg/kg
As systemic insecticide
Alpha-Hydroxybenzyl-
  phosphinic acid
  (Phosilit)
C?H903P
mp 110
                            Med. use:  to counteract
                            toxic effects of X-ray
                            therapy; the sodium salt as
                            nutritive in convalescence
Tonophosphan
CgH13NO2PNa-3H2O
Scales or
needles
Soluble in cold
water
                            Med. use:  As tonic
Diethyl p-nitro-
  phenyl phosphate
  (phosphacol)

C10H14N06P
Oily liquid
                            Med. use:  As a parasympa-
                            thomimetic and miotic
Aluminum
  phosphate
A1P04
White infusi-
ble powder
mp above 1,460°
                            As cement in admixture with
                            calcium sulfate and sodium
                            silicate; as flux for cera-
                            mics;  in dental cements;  for
                            special glasses.  Used in
                            pharmacy as the gel or dried
                            gel.   Med. use:  as gastric
                            antacid
                                                                                    (continued)

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     APPENDIX
                                       TABLE 4 (Continued)

           .PROPERTIES,  TOXICITY, AND USES OF PHOSPHORUS AND SOME PHOSPHORUS COMPOUNDS
 Compound
 Properties
          Toxicity
            Uses
Aluminum
  phosphide
A1P
Dark gray or
dark yellow
Must be protected from
moist air since it reacts
readily to produce phos-
phine, which is highly
toxic
As source of phosphine:
semiconductor research
in
Sodium phosphate,
  dibasic
Na2HPO4
Hygroscopic
powder
Anhydrous form may cause
mild irritation to skin,
mucous membranes; causes
purging when taken in-
ternally
As a mordant in dyeing; for
weighting silk, in tanning;
in manufacture of enamels,
ceramics, detergents, boiler
compounds; as fireproofing
agent; in soldering and braz-
ing instead of borax; as rea-
gent and buffer in analytical
chemistry.  Med. use:  As
mild saline cathartic; has
been used in phosphorus defi-
ciency and in lead poisoning.
Vet. use: As laxative for
foals, calves
Glycerophos-
  phoric acid

C3H9°6P
Clear syrupy
liquid
mp -25°
                            Absolute acid used to manu-
                            facture certain glycerophos-
                            phates or to impart taste to
                            solutions of glycerophosphates
                            which are generally used
                            medicinally
                                                                                     (continued)

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   APPENDIX
                                       TABLE 4 (Continued)

           PROPERTIES,  TOXICITY, AND USES OF PHOSPHORUS AND SOME PHOSPHORUS COMPOUNDS
Compound
 Properties
          Toxicity
            Uses
Lecithin
Waxy mass
Insoluble in
water
                            Is an edible and digestible
                            surfactant and emulsifier of
                            natural origin.  Used in mar-
                            garine, chocolate, and in
                            the food industry in general;
                            in pharmacueticals and cos-
                            metics; and for other indus-
                            trial uses, such as treating
                            leather and textiles.  Med.
                            use:  as lipotropic agent
Phosphoric acid
  2,2 dichloro-
  vinyl dimethyl
  ester (DDVP)

C4H7C12°4P
Nonflammable
liquid
A cholinesterase inhibi-
tor
     in rats 70 mg/kg
As insecticide for the con-
trol of agricultural and
household pests.  Used as
0.5% spray or 0.5% bait. Vet.
use:  for gastrointentinal
worms in swine, ruminants,
horses
Phosphoric acid
  dimethyl ester,
  ester with cis-
  3-hydroxy-N,N-
  dimethylcrotona-
  mide
  (Bidrin)
|C8H16N05P
Brown liquid
Highly toxic
See Parathion
A cholinesterase
inhibitor
     orally in rats
As insecticide
                   50
                      22 mgAg
                                                                                     (continued)

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         APPENDIX

                                         TABLE 4  (Continued)

            PROPERTIES, TOXICITY,  AND USES OF PHOSPHORUS AND SOME PHOSPHORUS COMPOUNDS
I Compound
  Properties
       Toxicity
            Uses
 Cupric phosphate
 Cu3(P04)2
Blue or olive
orthorhombic
crystals
                            As fungicide; as catalyst
                            for organic reactions; in
                            fertilizer; as emulsifier;
                            as corrosion inhibitor for
                            H-jPO^; protectant for metal
                            surfaces against oxidation
 Parathion O,
   O-diethyl
   O-p-nitriphenyl
   phosphorothionate
Yellowish
liquid
Highly toxic
Acute:  anorexia, nausea,
vomiting, diarrhea, ex-
cessive salivation, pupil-
lary constriction, bron-
choconstriction, muscle
twiching, convulsions,
coma, respiratory failure,
Effects are cumulative.
Special precautions
necessary to prevent in-
halation and skin conta-
mination
As agricultural insecticide
 Ammonium sodium
   phosphate
 NaNH HP04
Odorless
crystals
Mp approx 80°
                            As a reagent for determina-
                            tion of Mg and Zn,  and in
                            blowpipe analysis;  for
                            standardizing uranium solu-
                            tions; in the preparation
                            of ammonium phosphate and
                            ammonium molybdate stock
                            solutions
                                                                                    (continued')

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                                       TABLE 4 (Continued)

           PROPERTIES, TOXICITY, AND USES OF PHOSPHORUS AND SOME PHOSPHORUS COMPOUNDS
Compound
 Properties
          Toxicity
            Uses
Ferric phosphate
FePO,
White, gray, or
pink crystals
                            As food and feed supplement,
                            particularly in bread en-
                            richment; as fertilizer
Malathion
C10H19°6PS2
Deep brown to
yellow liquid
Produces symptoms similar
to those for parathion.
Malathion is, however,
considered to be less
toxic
As insecticide, particularly
effective against pear psylla,
red spider mites, and aphids;
appears to be about 100 times
less toxic to warm-blooded
animals than parathion, about
two to four times less toxic
to insects.  Vet use:
ectoparasiticide for horn
fly, lice in dairy cattle;
horn fly, lice, ticks in
btef cattle; lice, sheep ked
ticks in sheep and goats;
lice, sarcoptic mange in
swine; lice, ticks, mites
in poultry

-------
                                                             68
 APPENDIX
                            TABLE 5
         COMPARATIVE ACUTE TOXICITY OF CHOLINERGIC
ORGANOPHOSPHORUS  INSECTICIDES IN NORMAL MALE AND FEMALE RATS
52
Insecticide
Phosdrin
Systox
Guthion
Di-Syston
Parathion
Methyl
OMPA
Co-Ral
EPN
Trithion
Delnav
Ethion
Polex
Ronnel
Ma lath ion
Number
Male
35
35
37
35
57
52
78
36
70
72
75
36
54
38
48
of Rats
Female
35
60
37
32
41
44
39
45
44
34
32
37
44
25
39
LD50±SE*
Male
3.2*0.3
3.9*0.1
4.0±0.5
6 . 7± 0 . 6
8.1+-0.4
9.3±0.8
9.6±0.4
14.711.4
23.9+1.1
27.0+0.8
33.2+2.2
34.5+5.9
67.7+5.0
118.0116.2
193.0+25.9
(mgAg)
Female
1.2*0.1
1.4±0.1
8.7±0.6
2.1*0.1
2.5±0.4
7.0+0.6
28.7±1.3
7.510.4
7.3+0.5
10.1+0.8
17.2+0.9
25.911.8
124.018.8
2822.6+137.4
619.4125.0
      *SE=standard error.

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                TABLE  6

COMPARATIVE TOXICITIES OF  SOME PHOSPHORUS
   COMPOUNDS FOR EXPERIMENTAL ANIMALS
Toxic Substance
p-Nitrophenyldiethyl
thiophosphate (E.605)
isomer I
isomer II
p-Nitrophenyldiethyl
phosphate (E.600)
p-Nitrophenyldiethyl
thiophosphate
.
M
4-Methyl-7-hydroxy-
coumaryldi ethyl
thiophosphate (E.838)
Dimethyl p-nitrophenyl
thiophosphate
11
„
11
»
Concentration
Value
(ppm body wt)
3.0
1.2
0.5
0.4
10.0
II
II
II
15.0
II
II
II
10.0
II
II
11
15.0
II
II
II
Route6
iv
"
11
ip
n
n
n
iv
'•
11
"
„
»
Subiect Effect Ref .
Sinqle Exposure
Rat, male
"
Rabbit
.,
ll
ll
ll
ll
M
II
II
II
II
ll
ll
II
II
ll
LD
n
n
10EDa83
10ED8b
11ED66
HED9b
40ED81
40ED20b
20ED94
20ED26b
30ED97
30EDOb
10ED67
10EDOb
40ED64
40ED8b
10ED80
10ED6b
10ED8D
10ED6b
40ED65
40ED5D
1
II
II
II
II
:;
n
M
n
n
n
i
M
ii
•
ii
n
ti
i
                                                      (continued)

-------
APPENDIX
                               TABLE  6  (Continued)
                      COMPARATIVE TOXICITIES OF SOME PHOSPHORUS
                         COMPOUNDS FOR EXPERIMENTAL ANIMALS
Toxic Substance
Di-isopropyl p-nitro-
phenyl thiophosphate
"
Bis -dime thylaminof luo-
rophosphine oxide
"
11
n
11
11
p-Nitrophenyldiethyl
thiophosphate (E.605)
isomer I
isomer III
p-Nitrophenyldiethyl
phosphate (E.600)
4-Methyl-7-hydroxy-
phosphate
bis-dimethylaminoglu-
orophosphine oxide
11
11

Phosphorus oxychloride


Concentration
Value
(ppm body wt)

15.0
II

20.0
II
II
II
"
11

1.7X10"4
2.5X10-7
2.8X10"8

2.0X10"8
5.0X10"9

4.0X10"5
7.0X10"2
7.0X10"4
mq/m
61.3

56.3
Route6

iv
11

1
"
"
"
11
"

sol
II
II

II
II

II
"
11

ih


Sub -i act Effect Ref.
Sinqle Exposure

Rabbit
M

ll
II
11
"
1
"

Sheep0
11
II

1
11

Ratd
"
11
4 hours
Rat, female
20
II

10ED34
10ED21b

7 EDS 8
7ED31to
20ED86
20EDOb
42ED89
42EDOb

ED50b
II
II

11
II

b
mm ED,.,-,
n ->(J
"

LD50



1
"

n
"
n
11
II
II

11
11
II

1
"

1
II
11

79
"
"
                                                                                               a
                                                                            (Continued)

-------
APPENDIX
                                TABLE 6  (Continued)

                      COMPARATIVE TOXICITIES  OF SOME PHOSPHORUS
                         COMPOUNDS  FOR EXPERIMENTAL  ANIMALS


Toxic Substance
Phosphorus oxychloride

M
Phosphorus trichloride


Phosphorus trichloride
(vapors/aerosols )

11
Concentration
Value
(Moles)
66.6

52.4
132.1

152.4

63.5

132.0


Route
ih

ll
11

II

ll

li

Subiect Effect Ref.
Single Exposure
Guinea pig
male, 10
11
Rat, female
20
11

Guinea pig
male, 10
II
LD

II

II
11


II
II

1

ll

ll
H


ll
II
       aED = Effective dose for inhibition of cholinesterase.   The sight-hand subscript
 indicates the percent inhibition of cholinesterase and the left-hand one showes time
 (min)  after injection or of incubation.

        in vitro inhibition.

       °Incubation at 37° C, sheep red cells.

        Brain, auxiliary glands,  red cells,  brain serum,  and heart.

       eiv = intravenous; ip = intraperitoneal;  ih = inhalation; sol = solution

-------
APPENDIX
                                      TABLE 7
                      PRODUCTION OF PHOSPHORUS CHEMICALS
                               (Thousand Short Tons)
19,20
Phosphorus Chemicals
Phosphoric acid, total
Phosphorus, elemental
Phosphorus oxychloride
Phosphorus pentasulfide
Potassium pyrophosphate
Calcium phosphate, basic
Sodium phosphate, tripoly
Potassium pyrophosphate
1964a
3,283
504
27
42
52
242
886
52
1965a
3,905
550
27
50
55
263
923
55
1966a
4,549
566
31
54
53
290
1,001
53
1967b
4,764
583
33
45
53
380
1,046
53
. 1968°
5,202
620
34
58
63
339
1,072
63
1969C
5,690
652
36
64
69
356
1,117
69
    aU.S.  Department of Commerce.
     Preliminary data.
    CC & EN computer forecasts.

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                                                            73
                          TABLE 8

    GROWTH OF  PHOSPHORIC  ACID INDUSTRY IN UNITED STATES2
                  (ton/year  100% P->OC
Year               Thermal  process	          Wet process
1941
1942
1943
1944
1945
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
108,494
104,655
103,418
111,157
132,149
191,911
211,578
259,677
295,073
330,096
357,622
462,580
506,774
540,025
570,235
632,954
657,372
740, 747
762,531
844, 761
869,805
947,293
1,007,624
l,007,941a
131,521
118,970
127,248
141,141
132,599
174,987
220,828
245,427
299,152
338,426
388,908
496,152
631,252
774,998
811,770
936,129
1,033,205
1,140,658
1,324,695
1,409,173
1,576,976
1,957,476
2,275,418
2,837,119
         aSubject to revision

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                            TABLE  9

       THERMAL-PROCESS PHOSPHORIC ACID ESTABLISHMENTS
                       IN UNITED STATES2
                                                            74
State
          Company
   Location
Alabama

California
Tennessee Valley Authority    Wilson Dam
Colorado


Georgia

Idaho


Illinois



Indiana
F M C Corporation
Monsanto Company
Stauffer Chemical Company
Stauffer Chemical Company

Colorado Fuel and Iron
Corporation

Monsanto Company

El Paso Natural Gas Company
Monsanto Company
Stauffer Chemical Company
Stauffer Chemical Company

Hooker Chemical Company
Mobil Chemical Company
Newark
Long Beach
Richmond
South Gate

Pueblo
(not operating)

Augusta

Georgetown
(not operating)

Sauget
Chicago Heights
South Chicago

Jeffersonville
Gary
Kansas
Massachusetts
Michigan
Montana
New Jersey

New York
Ohio
F M C Corporation
Hooker Chemical Company
Monsanto Company
Stauffer Chemical Company
Agrigo Chemical Company
Continental Oil Company
F M C Corporation
Monsanto Company
Hooker Chemical Company
Mobil Chemical Company
Monsanto Company
Lawrence
Adams
Trenton
Butte
Carteret
Carteret
Carteret
Kearny
Niagara Falls
(not operating)
Fernald
Addyston
                                                   (continued)

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                                                           75
                    TABLE  9  (Continued)

        THERMAL-PROCESS PHOSPHORIC ACID ESTABLISHMENTS
                        IN UNITED STATES2
State	Company	Location

Pennsylvania    Stauffer Chemical Company     Morrisville

South Carolina  Mobil Chemical Company        Charleston

Tennessee       Hooker Chemical Company       Columbia
                Stauffer Chemical Company     Nashville

Texas           Hooker Chemical Company       Dallas

Wyoming         F M C Corporation             Green River

-------