United States
               Environmental Protection
               Agency
                Office of Health and
                Environmental Assessment
                Washington DC 20460
EPA-600/8-83-013
June 1983
External Review Draft
               Research and Development
?,EPA
Health Assessment
Document for
Manganese

Part 1  of 2
 Review
 Draft
 (Do Not
 Cite or Quote)
                             NOTICE

               This document is a preliminary draft. It has not been formally
               released by EPA and should not at this stage be construed to
               represent Agency policy. It is being circulated for comment on its
               technical accurecy and policy implicetions.

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                                               EPA-600/8-83-013
                                               External Review Draft
                            DRAFT
                     Do not cite or quote
                  HEALTH ASSESSMENT DOCUMENT
                             FOR
                          MANGANESE
                            Notice

This  document  1s  a  preliminary  draft.   It  has  not  been
formally released  by  EPA and  should not  at  this stage  be
construed to  represent  Agency policy.   It 1s being  circu-
lated for comment  on  Us technical  accuracy and  policy  Im-
plications.
             U.S.  ENVIRONMENTAL PROTECTION AGENCY
              Office of Research and Development
        Office of  Health and Environmental Assessment
         Environmental  Criteria and Assessment  Office
                    Cincinnati, OH  45268
           Project Managers:   Dr.  Linda S.  Erdrelch
                              Dr.  Jerry F.  Stara
    [1 C^ r-

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                                   DISCLAIMER







    This report  1s an  external  draft for  review purposes  only  and does  not



constitute  Agency policy.  Mention  of  trade names or commercial  products  does



not constitute endorsement or  recommendation for  use.
                                      11







1794A                                                                5/06/83

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                                   PREFACE
    The  Office  of  Health  and  Environmental  Assessment  of  the  Office  of
Research and  Development  has prepared this  Health  Assessment Document (HAD)
at  the  request of  the Office of  A1r  Quality Planning and Standards (OAQPS).
Manganese  1s  one of  several  metals  and  associated  compounds emitted  to the
ambient air  which  are currently  being  studied by  the  Environmental Protec-
tion Agency  to determine whether  they  should be regulated  as hazardous air
pollutants under the Clean A1r Act.
    A Multimedia Health Assessment for Manganese  had been drafted 1n 1979 to
evaluate the  health effects of  manganese.   The  original  document  has since
been modified  1n scope and  emphasis  and  updated.   This  HAD 1s designed to be
used by OAQPS for decision making.
    In  the development of  this  assessment  document, the  scientific litera-
ture has been  Inventoried,  key studies have  been  evaluated and summaries and
conclusions  have  been  directed  at  qualitatively  Identifying  the  toxic
effects of manganese.  Observed  effect   levels  and  dose-response  relation-
ships  are  discussed  where   appropriate  1n   order   to  Identify  the  critical
effect  and to  place  adverse health  reponses 1n  perspective with  observed
environmental levels.
                                     111
1794A                                                                5/09/83

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                 LIST OF AUTHORS,  CONTRIBUTORS AND REVIEWERS
Dr. D1nko Kello (author)
Institute for Medical Research
Zagreb, Yugoslavia

Mr. Randall J.F.  Bruins (author)
ECAO-C1n, U.S. Environmental Protection Agency

Dr. Linda S. Erdrelch (author, document manager)
ECAO-C1n, U.S. Environmental Protection Agency

Dr. Jerry F. Stara (document manager)
ECAO-C1n, U.S. Environmental Protection Agency

Dr. Steven J. Bosch
Syracuse Research Corporation
Syracuse, NY

Dr. Tom Clarkson
University of Rochester
Rochester, NY

Dr. Herb Cornish
School of Public Health
University of Michigan
Ann Arbor, MI

Dr. Michael Dourson, ECAO-C1n
U.S. Environmental Protection Agency

Dr. D. Anthony Gray
Syracuse Research Corporation
Syracuse, NY

Dr. Paul Hammond
University of Cincinnati
Cincinnati, OH

Dr. Rolf Hartung
School of Public Health
University of Michigan
Ann Arbor, MI

Dr. Bernard Haberman
Carcinogen Assessment Group
U.S. Environmental Protection Agency
Washington, DC

Dr. T.J. Knelp
NYU Medical Center
Tuxedo, NY
                                      1v
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Dr. James Lai
Burke Rehabilitation Center
Dementia Research
White Plains, NY

Mr. C.A. Hall
Ethyl Corporation
Ferndale, MI

Dr. Fred Moore
Elklns Metal Company
Marietta, OH

Dr. Debdas Mukerjee, ECAO-CIn
U.S. Environmental Protection Agency

Dr. Nancy Pate
U.S. Environmental Protection Agency
Office of A1r Quality Planning and Standards
Research Triangle Park, NC

Dr. W. Bruce Pelrano, ECAO-C1n
U.S. Environmental Protection Agency

Dr. William Pepelko, ECAO-C1n
U.S. Environmental Protection Agency

Dr. Mangus Plscator
School of Public Health
University of Pittsburgh
Pittsburgh, PA

Dr. Ivan Rabar
Institute for Medical Research
Zagreb, Yugoslavia

Dr. Marco Sarlc
Institute for Medical Research
Zagreb, Yugoslavia

Dr. Samuel Shlbko
Contaminants and Nat. Toxic. Evaluation Branch
Division of Toxicology, Food and Drug Administration
Washington, DC

Dr. Ellen Sllbergeld
Environmental Defense Fund
Washington, DC

Dr. Melvyn Tochman
John Hopkins Hospital
Baltimore, MD
1794A                                                                 5/11/83

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Dr.  Otto Weber
Institute for Medical  Research
Zagreb, Yugoslavia

Dr.  David Well
Environmental Criteria and Assessment Office
U.S. Environmental Protection Agency
Research Triangle Park, NC

Dr.  James WUhey
Food Directorate, Bureau of Chemical Safety
Ottawa, Ontario
Special Acknowledgement:    Technical Services and Support Staff, ECAO-C1n
                            U.S.  Environmental Protection Agency
                                      v1


1794A          ?                                                     5/11/83

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                              TABLE OF CONTENTS

                                                                        Page
 1.  INTRODUCTION	    1-1

 2.  SUMMARY AND CONCLUSIONS	    2-1

     2.1.  SUMMARY OF EXPOSURE	    2-1
     2.2.  SUMMARY OF BIOLOGICAL ROLE AND HEALTH EFFECTS  	    2-6

           2.2.1.  Biological Role 	    2-6
           2.2.2.  Tox1c1ty	    2-7

     2.3.  CONCLUSIONS	    2-11

 3.  GENERAL PROPERTIES AND BACKGROUND INFORMATION 	    3-1

     3.1.  PHYSICAL AND CHEMICAL PROPERTIES	    3-1

           3.1.1.  Manganese Compounds 	    3-4

     3.2.  SAMPLING AND ANALYTICAL METHODS 	    3-8

           3.2.1.  Sampling	    3-9
           3.2.2.  Sample Preparation	    3-14
           3.2.3.  Analysis	    3-15

     3.3.  PRODUCTION AND USE	    3-17

           3.3.1.  Production	    3-17
           3.3.2.  Use	    3-24

     3.4.  SOURCES OF MANGANESE IN THE ENVIRONMENT	    3-27

           3.4.1.  Crustal Materials and Soils 	    3-27
           3.4.2.  Industrial and Combustion Processes 	    3-30
           3.4.3.  Relative Importance of Manganese Sources at
                   Several Locations as Determined by Mass Balance
                   and Enrichment Models 	    3-38

     3.5.  ENVIRONMENTAL FATE AND TRANSPORT PROCESSES	    3-48

           3.5.1.  Principal  Cycling Pathways and Compartments . .  .    3-48
           3.5.2.  Atmospheric Fate and Transport	    3-50
           3.5.3.  Fate and Transport 1n Water and Soil	    3-54

     3.6.  ENVIRONMENTAL LEVELS AND EXPOSURE 	    3-60

           3.6.1.  A1r	    3-60
           3.6.2.  Water 	    3-75
           3.6.3.  Food	    3-79
           3.6.4.  Human Exposure	    3-81
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     3.7.  SUMMARY OF GENERAL PROPERTIES AND BACKGROUND INFORMATION.
                                                                        Page
   3-89
           3.7.1.   Chemical and Physical Properties	    3-89
           3.7.2.   Sampling and Analysis 	    3-89
           3.7.3.   Production and Use	    3-91
           3.7.4.   Sources of Manganese 1n the Environment 	    3-92
           3.7.5.   Environmental Fate and Transport Processes. .  .  .    3-94
           3.7.6.   Environmental Levels and Exposure 	    3-95

 4.  BIOLOGICAL ROLE AND PHARMACOKINETICS	    4-1

     4.1.  BIOLOGICAL ROLE OF MANGANESE	    4-1

           4.1.1.   Biochemical Role	    4-1
           4.1.2.   Manganese Deficiency	    4-1
           4.1.3.   Manganese Requirements	    4-2
           4.1.4.   Summary 	    4-2


     4.2.  COMPOUND DISPOSITION AND RELEVANT PHARMACOKINETICS. ...    4-3

           4.2.1.   Absorption	    4-3
           4.2.2.   Distribution and Normal Tissue Levels 	    4-6
           4.2.3.   Excretion 	    4-10
           4.2.4.   Biological Half-time	    4-12
           4.2.5.   Homeostasls 	    4-13
           4.2.6.   Summary 	    4-20

     4.3.  SYNERGISTIC/ANTAGONISTIC FACTORS	    4-21

           4.3.1.   Interaction with Metals 	    4-21
           4.3.2.   Effect of Age	    4-23
           4.3.3.   Summary 	    4-26

 5.  TOXIC EFFECTS AFTER ACUTE EXPOSURE	    5-1

     5.1.  ANIMAL  STUDIES	    5-1
     5.2.  HUMAN STUDIES	    5-4
     5.3.  SUMMARY	    5-5

 6.  TOXIC EFFECTS AFTER CHRONIC EXPOSURE	    6-1

     6.1.  NEUROTOXIC EFFECTS — HUMAN STUDIES 	    6-1

           6.1.1.   Case Reports and Ep1dem1olog1c Studies	    6-3
           6.1.2.   Pathology of Manganese Poisoning	    6-14
           6.1.3.   Summary 	    6-14
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                                                                        Page
     6.2.   NEUROTOXIC EFFECTS — ANIMAL STUDIES	     6-15

           6.2.1.   Mechanism of  Manganese NeurotoxIcUy	     6-23
           6.2.2.   Altered Neurotransmltter  Metabolism 	     6-25
           6.2.3.   Summary 	     6-35

     6.3.   LUNG EFFECTS	     6-36

           6.3.1.   Human Studies 	     6-36
           6.3.2.   Animal Studies	     6-46

     6.4.   REPRODUCTIVE EFFECTS	     6-58

           6.4.1.   Human Studies 	     6-58
           6.4.2.   Animal Studies	     6-58
           6.4.3.   Summary 	     6-61

     6.5.   HEMATOLOGIC EFFECTS 	     6-62

           6.5.1.   Human Studies 	     6-62
           6.5.2.   Animal Studies	     6-63
           6.5.3.   Summary 	     6-64

     6.6.   CARDIOVASCULAR SYSTEM EFFECTS 	     6-65

           6.6.1.   Human Studies 	     6-65
           6.6.2.   Animal Studies	     6-66
           6.6.3.   Summary	     6-66

     6.7.   BIOCHEMICAL EFFECTS 	     6-66

           6.7.1.   Human Studies 	     6-66
           6.7.2.   Animal Studies	     6-67
           6.7.3.   Summary 	     6-68

     6.8.   DIGESTIVE SYSTEM EFFECTS	     6-68

           6.8.1.   Gastrointestinal Tract Effects	     6-68
           6.8.2.   Liver Effects 	     6-69
           6.8.3.   Summary 	     6-71

     CARCINOGENICITY 	     7-1

     7.1.   ANIMAL  STUDIES	     7-1
     7.2.   HUMAN STUDIES	     7-7
     7.3.   SUMMARY	     7-10
                                      1x
1794A                                                                5/09/83

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                                                                        Page


 8.  MUTAGENICITY AND TERATOGENICITY 	    8-1

     8.1.  MUTAGENICITY	    8-1

           8.1.1.  Tests for Gene Mutations	    8-1
           8.1.2.  Tests for Chromosomal Damage	    8-1
           8.1.3.  Tests for Other Genetic Damage	    8-1

     8.2.  TERATOGENICITY	    8-3
     8.3.  SUMMARY	    8-4

 9.  EFFECTS OF CONCERN AND HEALTH HAZARD EVALUATION 	    9-1

     9.1.  EXISTING GUIDELINES,  RECOMMENDATIONS AND STANDARDS. ...    9-1

           9.1.1.  A1r	    9-1
           9.1.2.  Water 	    9-1

     9.2.  SUMMARY OF TOXICITY	    9-2
     9.3.  SPECIAL GROUPS AT RISK	    9-5
     9.4.  EFFECTS OF MAJOR CONCERN AND EXPOSURE/RESPONSE INFORMATION   9-7

           9.4.1.  Effects of Major Concern	    9-7
           9.4.2.  Exposure/Response Information 	    9-7

     9.5.  HEALTH HAZARD EVALUATION	    9-11

           9.5.1.  Critical Effect and Effect Levels 	    9-11

10.  REFERENCES	   10-1

APPENDIX: ESTIMATING HUMAN EQUIVALENT INTAKE LEVELS FROM ANIMAL
          STUDIES	    A-l
1794A                                                                5/09/83

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                                LIST OF  TABLES


 No.                               TUIe                                Page

3-1      Physical  Properties  of Manganese	     3-2

3-2      Normal  Oxidation Potentials of  Manganese Couples	     3-3

3-3      Physical  Properties  of Some Manganese Compounds 	     3-5

3-4      Relative  Sensitivity of Some Important Analytical  Techniques
         for Manganese	     3-18

3-5      Estimated United States Production,  Capacity and  Use of
         Selected  Manganese Compounds	     3-21

3-6      Manganese Supply-Demand Relationships, 1969-1979	     3-22

3-7      Net United States Production of Ferromanganse and
         SHIcomanganese	     3-23

3-8      Commercial Forms of  Manganese 	     3-25

3-9      Manganese Content of Selected Minerals	     3-29

3-10     Sources and Estimated Atmospheric Emissions of Manganese
         1n 1968	     3-31

3-11     Estimated Manganese  Emissions from Controlled Submerged-Arc
         Furnaces  Producing Manganese Alloys  	     3-34

3-12     Manganese Concentrations of Coal, Fuel 011, Crude  011,
         Gasoline, Fuel Additives and Motor 011	     3-35

3-13     Manganese Content 1n Coal Ash	     3-36

3-14     Manganese Concentration 1n Fine (<2.0 urn) and Coarse
         (2.0-20 v.m) Particle Fractions of Aerosols from Several
         Sources 1n the Portland Aerosol Characterization  Study. .  .     3-40

3-15     Manganese Concentrations 1n Aerosols from Various  Sources,
         and Estimated Percent Contribution of Each Source  to Observed
         Ambient Manganese and Total Aerosol  Mass at Two Sites . .  .     3-42

3-16     Manganese Concentrations 1n Aerosols from Various  Sources,
         and Estimated Percent Contribution of Each Source  to
         Observed  Ambient Mn  and Total Aerosol Mass, Based  on Target
         Transformation Factor Analysis	     3-43

3-17     Number  of National A1r Surveillance  Network Stations within
         Selected  Annual Average Manganese A1r Concentration
         Intervals, 1957-1969	     3-61
                                      x1
1794A                                                                5/09/83

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                            LIST OF  TABLES (cont.)


 No.                               Title                                Page

3-18     National  A1r Surveillance Network Stations with Annual
         Average Manganese A1r Concentrations Greater Than
         0.5 ug/m3	     3-62

3-19     Average Manganese Concentration 1n Ambient A1r and Total
         Suspended Partlculates (TSP) 1n Urban and Nonurban NASN
         Sites,  1966-1967	    3-64

3-20     Urban NASN Sites, 1970-1982: National Cumulative Frequency
         Distributions of Quarterly  Values for Manganese Concentration  3-66

3-21     Nonurban  NASN Sites,  1970-1982: National  Cumulative Frequency
         Distributions of Quarterly  Values for Manganese Concentration  3-67

3-22     Manganese Concentrations 1n A1r, Kanawha  Valley Area,
         West Virginia	    3-68

3-23     Ambient A1r  Sampling  Data for Total Suspended Partlculates
         and Manganese (1n ug/m3) 1n the Marietta, OH-Parkersburg, WV
         Vicinity, 1965-1966 and 1982-1983 	    3-70

3-24     Concentrations of Trace Metals 1n A1r Measured at Three
         Locations 1n New York City	    3-71

3-25     Selected  Dlchotomous  Sampler Data on Manganese and Particle
         Mass from 22 U.S. CH1es 1n 1980	    3-74

3-26     Concentration of Manganese  1n Various Lake and River Waters    3-76

3-27     Mean Concentrations of Dissolved Manganese by Drainage Basin   3-77

3-28     Dissolved and Suspended Manganese 1n Five U.S. Rivers . . .    3-78

3-29     Cumulative Frequency  Distribution of Manganese Concentration
         1n Tap Waters Sampled 1n the HANES I Augmentation Survey of
         Adults	    3-80

3-30     Estimates of Human Inhalation Exp]osure to Manganese 1n
         Ambient A1r	    3-85

3-31     Dietary Intake of Manganese 1n the U.S	    3-86

3-32     Intake of Manganese from Food by Children	    3-88

4-1      Manganese 1n Human Tissues	    4-7

4-2      Concentrations of Manganese 1n Liver, Kidney and Brain. . .    4-16
1794A                                                                5/09/83

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                            LIST OF TABLES (cont.)
No.
5-1
5-2
6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
6-10
6-11
7-1
7-2
7-3
9-1
A-l
TUle
Acute LDcQ Values for Manganese Compounds 	
Influence of Age on Manganese ToxIcUy 1n Rats: 10$$ Values
8 Days after a Single Oral Administration of MnCl2 	
Studies of Manganlsm 1n Humans and Exposure-Response
Relationship 	
Frequency of Abnormal Neurological Findings 	
Ferroalloy Workers with Neurological Signs by Level of
Exposure to Manganese 	
Neurotoxlc Effects of Manganese 1n Experimental Animals . .
Neurological Signs Induced by Manganese 1n Monkeys 	
Prevalence of Chronic Bronchitis 1n Groups of Workers
According to Smoking Status 	
Cumulative Incidence of Acute Respiratory Diseases During
the 3-Year Period 	
Summary of Human Studies of Respiratory Effects at Various
Levels of Exposure to Manganese 	
Respiratory Effects with Manganese Exposure: Intratracheal,
Intraperltoneal and High Dose Inhalation Exposures 	
Respiratory Effects with Manganese Exposure: Inhalation
Exposures at Low Doses 	
Pulmonary Physiology Data for Male and Female Monkeys After
Nine Months of Exposure 	
Pulmonary Tumors 1n Strain A Mice Treated with Manganese
Sulfate 	
Carc1nogen1dty of Manganese Powder, Manganese Dioxide and
Manganese Acetylacetonate 1n F344 Rats and Swiss Albino
Mice 	
Induction of Sarcomas 1n Rats by the Intramuscular
Injection of Manganese Dust 	
Studies of Manganese Inhalation 1n Animals -- Summary of
Effect Levels 	
Exposure Effect Information for Health Hazard Evaluation:
Human Equivalent Exposure Levels Estimated from Animal Data
Paqe
5-2
5-3
6-5
6-8
6-12
6-17
6-21
6-41
6-45
6-47
6-48
6-54
6-56
7-2
7-4
7-8
9-9
A-3
                                     X111
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                               LIST OF FIGURES
No.
3-1
3-2
6-1
THle
The Global Cycles of Manganese 	
Concentration Factors for Manganese 1n Hudson River ....
Schematic Representation of the Mechanisms of Actions of
Manganese on the Central Dooam1nera1c Svstem 	
Page
3-49
3-59
6-27
                                     x1v
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                               1.   INTRODUCTION
    The purpose  of  this document  1s  to  summarize  the current  knowledge  of
the  effects   of   exposure  to  environmental  manganese  upon  human  health.
Manganese  1s  an  essential  trace  element  for  all   living  organisms,  and
chronic manganese  toxldty from  occupational  exposure  1s well  documented.
For  this   reason,   the   potential   human   health  hazard  from  environmental
exposure must be evaluated.  In order to  assess  the  effects on human health,
the  general   properties,  ambient  levels  and  biological  availability  of
manganese from environmental  media must  be considered.
    The rationale  for  structuring  the  document  1s   based  primarily on  two
major  Issues, exposure  and response.   The first portion  of  the document  1s
devoted to manganese  1n the environment:  physical  and  chemical properties,
the  monitoring  of  manganese  1n  various  media,   natural  and  human-made
sources,  the  transport  and  distribution  of  manganese within  environmental
media, and the levels of exposure.  The  second part  1s devoted to biological
responses  1n  laboratory animals  and  humans Including metabolism,  pharmaco-
klnetlcs,  mechanisms   of  toxldty,  as   well  as  toxlcologlcal  effects  of
manganese.
    This  assessment document 1s based on  original  publications, although the
overall  knowledge  covered by  a  number   of   reviews  and  reports  was  also
considered.  The  references cited were  selected  to  reflect the current state
of knowledge on  those  Issues which  are  most relevant  for a health assessment
of manganese 1n the environment.
0202P                               1-1                              5/09/83

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                         2.   SUMMARY AND CONCLUSIONS
2.1.   SUMMARY OF EXPOSURE
    Manganese 1s a ubiquitous  element  1n the earth's crust,  1n  water  and 1n
partlculate matter 1n  the atmosphere.    In  the  ground state, manganese  1s  a
gray-white metal  resembling Iron,  but  harder  and  more  brittle.   Manganese
metal forms numerous  alloys  with Iron,  aluminum and  other metals.
    There are numerous  valence  states  for manganese, with  the  divalent  form
giving the most stable  salts and  the tetravalent  form giving the most  stable
oxide.  The  chlorides,  nitrates  and  sulfates of manganese (II) are  highly
soluble 1n water,  but   the  oxides,  carbonates and  hydroxides are only spar-
ingly soluble.  The  divalent  compounds are stable  1n add  solution,  but are
readily oxidized 1n alkaline conditions.  The heptavalent form  1s  found  only
1n oxy-compounds.
    Sampling  of  manganese In ambient  air  may be carried out by any  of  the
methods  used for  collecting  atmospheric  partlculate  matter.   High-volume
samplers with glass  fiber filters  are widely used  to measure  total  ambient
aerosol.  If  Information  on particle size  1s  desired the dlchotomous  sampler
1s  often  used,   which  separately  collects  fine  (<2.5  urn)   and   coarse
(>2.5 um) particles.
    Water, soil  and  food are  collected  for manganese analysis  by  the usual
techniques Insuring representative  sampling without contamination.   Biologi-
cal materials  such as   urine,  blood,  tissues, hair,  etc.,  are  collected and
stored  so  as  to prevent  contamination by dust;  no  other special  procedures
are required when sampling for manganese analysis.
    Sample preparation  and  analysis 1s  the same  for manganese  as  for other
nonvolatile metals.   Atomic absorption  spectrophotometry,  optical  emission
spectrometry and X-ray  fluorescence are  commonly  used.   Detection  limits for
                                                  3
manganese 1n air usually are as low as 0.002

0201P                               2-1                              5/06/83

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    Very little manganese  1s  mined  1n this country; some  1s  mined  domestic-
ally as  low-grade ores, but  most 1s  Imported.   Ferromanganese and  sH1co-
manganese are  ferroalloys  produced by  the smelting of  manganese  ore  1n  an
electric furnace.  Manganese  metal  1s produced by add  leaching of  the ore,
precipitation of  other  metals,  and  electrolysis of the  solution.   Manganese
alloys   and  metal are  then used  to  Introduce manganese  Into steel or  non-
ferrous alloys.
    Metallurgy,   especially  steel  making,  accounts  for  -95%  of   United
States   demand  for manganese.   Production  of  manganese alloys  1s declining,
since  demand  has diminished recently  and   Imports  are  Increasing.   The
remaining 5-6%  of manganese  demand  1s  for a  number  of  compounds which  are
Important 1n the chemical  Industry and 1n battery manufacture.
    Methylcyclopentadlenyl  manganese  trlcarbonyl  (MMT) has  been produced  and
used 1n  small  quantities   as  a  fuel  additive since 1958.   Major  use  as  an
octane  Improver  1n unleaded gasoline  (at 0.125 g Mn/gal) began 1n  1974,  but
was  discontinued 1n  1978   due  to  adverse  effects  on  catalytic  converter
performance and  hydrocarbon  emissions.  MMT  continues  to  be used  at  ~0.05
g/gal In -20% of  leaded gasoline.
    Manganese  1s  the  12th most  abundant  element  and  fifth most  abundant
metal 1n the earth's  crust.   While  manganese  does not exist  free 1n  nature,
1t  1s a  major  constituent  1n  at  least 100 minerals and  an  accessory  element
1n  more  than 200 others.   Its  concentration  1n various crustal components
and  soils  ranges from  near  zero  to  7000  ug/g; a mean  soil  content  of  560
y.g/g has been  given.   Crustal  materials  are an  Important source  of  atmo-
spheric  manganese due to   natural and anthropogenic  activities (e.g.,  agri-
culture, transportation, earth-moving)  which  suspend  dusts and soils.   The
resulting aerosols consist  primarily of coarse particles  (>2.5 vim)-


0201P                               2-2                              5/06/83

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    Manganese 1s also released to  the atmosphere  by  manufacturing processes.
Furnace emissions  from manufacture  of  ferroalloys,  Iron,  and  steel are  a
major  source  of fine partlculate  emissions with  a  high manganese  content.
Fossil fuel  combustion  also results In manganese release.   Coal  fly  ash  1s
about  equal  to  soil  1n  manganese content,  but  contains particles  finer  1n
size.  This  1s  an Important manganese  source  because of the  volume  of  coal
burned each  year.   Combustion  of  residual  oil  1s less  Important  because  of
Us  lower  mangnese  content.   About 15-30% of  manganese  combusted  1n  MMT-
contalnlng gasoline Is emitted  from the  tailpipe.
    The  relative  Importance  of   emission  sources  Influencing  manganese
concentration at  a given monitoring  location can  be estimated  by  chemical
mass  balance  studies.   Studies  1n St.  Louis and  Denver  suggest  that crustal
sources are  more  Important  1n  the coarse  than 1n the fine  aerosol fraction.
Conversely,  combustion sources such as  refuse Incineration  and vehicle emis-
sions  predominantly  affect  the  fine fraction.   In an  area  of  steel  manufac-
turing, the  Influence of  this process  was  seen  1n both the fine  and coarse
fractions.
    Atmospheric  manganese 1s present 1n several forms.   Coarse dusts contain
manganese  as  oxides, hydroxides  or  carbonates  at low  concentrations  (<1  mg
Mn/g).  Manganese  from  smelting  or combustion processes 1s often  present  1n
fine  particles  with   high concentrations  of manganese  as  oxides  (up  to 250
mg/g).  Organic manganese  usually 1s   not  present 1n  detectable  concentra-
tions.
    Oxides of  manganese  are  thought to  undergo  atmospheric  reactions  with
sulfur dioxide  or  nitrogen  dioxide to  give the   divalent sulfate  or  nitrate
salts.  Manganous  sulfate has  been shown  to catalyze SO   transformation  to
sulfurlc add,  but  the manganese  concentration  necessary for a significant
catalytic  effect has been disputed.

0201P                               2-3                               5/06/83

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    Atmospheric manganese  1s  transported by  air  currents  until  dry or  wet
deposition occurs.   In  New York City,  dry  deposition occurred more  quickly
for manganese  than most  other  metals,  because  1t tended  to  be present  1n
                                                                           2
larger  particles.    Dry  deposition  of  manganese  averaged  300-670  ng/cm /
                                                2
month,  whereas wet  deposition  was  -120  ng/cm /month.   Over much  of  the
United States  1n  1966-1967, wet  deposition  of manganese  ranged from  <10-540
     2
ng/cm /month.   Near  a  ferromanganese  plant  1n   1964-1965,  dry  deposition
                           2
was as high as 19,300 ng/cm /month.
    In water or soil, manganese  Is usually  present  as the divalent  or tetra-
valent form.   Divalent manganese 1s soluble and relatively  stable 1n  neutral
or acidic conditions.  Manganese tends  to be  mobile 1n oxygen-poor  soils and
1n  the  groundwater environment.  Upon  entering  surface  water, manganese  1s
oxidized and  precipitated,  primarily  by bacterial  action.   If  the  sediments
are  transported  to  a  reducing  environment  such  as  lake  bottom,  however,
mlcroblal reduction  can  occur,  causing  re-release of divalent manganese  to
                                                                       3   4
the water  column.   Manganese  1s bloconcentrated  (by a  factor  of  10 -10 )
                                                                           2
1n  lower organisms;  however,   the  concentration  factor  decreases  (10-10 )
as  trophic   level  Increases.   Thus  blomagnlf 1cat1on  of  manganese does  not
occur.
    A rough  assessment  of trends 1n  nationwide  air  sampling  data  Indicates
that  manganese concentrations  have  declined  during  the period of  record.
The arithmetic mean  manganese concentration  of  urban air  samples  decreased
from  0.11   ug/m3  In   1953-1957  to  0.073  ug/m3  1n   1966-1967,   and  to
           3
0.033  vig/m   1n  1982.   In  1953-1957,   the  percentage   of  urban  stations
                                         T
with  an  annual  average  of  >0.3  ug/m   was  ~10X.    By  1969  these  had
dropped to <4%, and since 1972 the number has been <1X.
0201P                               2-4                              5/06/83

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    The  highest  manganese  concentrations,  with  some  observations exceeding
        3
10  ug/m ,  were  seen  1n  the 1960s  1n  areas  of  ferromanganese manufacture.
More  recent  measurements 1n  these  areas  Indicated decreases  of  at least an
order  of  magnitude  had  occurred,  although  definitive  studies  were  not
available.
    Manganese   1s   associated  with   both   fine   (<2.5 vim)   and   coarse
(>2.5 vim)  particles,  but  the  manganese  concentration  1n each  fraction 1s
highly variable.  On  the average,  <16% of manganese 1n aerosol mass 1s found
1n fine  particles;  however,  1t 1s  estimated that 1n some  situations the  fine
fraction could contain as much as 50%.
    Manganese  concentrations  1n  nonpolluted  freshwaters are   usually  <20
vig/i,   but  may  exceed  1000  vig/8.   where   polluted.    Concentrations  1n
groundwater  typically  are   higher   than  1n  surface   water.   Concentrations
>1000  ug/i  are   found 1n  some  drinking  waters,  but   ~95X  of   water
supplies  contain manganese   at  <100  vg/fc-   A  median  concentration of  4
y.g/9.  for public  supplies has been  reported.
    Total  human  exposure to  manganese  may  be estimated  from Information on
levels 1n  air,  water  and  diet.   Inhaled  particles can  be  deposited  either
extrathoradcally,  1n  the  tracheobronchlal  region, or  1n the alveoli.  Time
required for particle  clearance  and probability  of absorption Increases with
Increasing  depth of  deposition  1n  the  respiratory  tract.   Deposition of
manganese  1n  the alveoli can be  calculated  from  the  ambient concentration
and the  fraction  present 1n  fine particles.   Thoracic (tracheobronchlal plus
alveolar) deposition  1s  calculated from estimates  of  the manganese found 1n
particles  <15  vun  1n  size.    Alveolar  deposition  of  manganese  at  current
ambient  levels  1s estimated  as  0.072  vuj/day as  an  average  and 6.6  vig/day
under  high  exposure conditions.   Estimates  of total  thoracic deposition are


0201 P                                2-5                              5/06/83

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slightly  higher;  0.26 jig/day  (average)  and 10.0  v.g/day  (high).   Alveolar
and  total  thoracic  deposition   under  the  high  exposure  conditions  (10
    3
vig/m )  of  the 1960s  were  estimated  to  be  100  and  152  v-9/day,  respec-
tively.
    Diet 1s the main source  of Ingested  manganese.   Average adult Intake has
been variously  estimated  at 2.3-5.5  mg/day.   On a  body-weight  basis,  expo-
sure Increases  from 0.002-0.004  mg/kg/day 1n Infants to  0.06-0.08 mg/kg/day
1n adults.  Drinking water usually comprises only  a very  small  proportion of
total   1ngest1on  exposure.   The  median  Intake  level via  drinking water  1s
-0.008  mg/day,   but   can  be   as  high  as  -2.0   mg/day   for   some  water
supplies.   The  1ngest1on  of  particles cleared  from  the respiratory  tract 1s
an even smaller source, probably  constituting no  more than  0.01  mg/day under
the highest ambient exposure conditions currently observed.
2.2.   SUMMARY OF  BIOLOGICAL ROLE AND HEALTH EFFECTS
2.2.1.    Biological Role.  Manganese  1s  widely  distributed  within  the  human
and animal  body  1n  constant  concentrations  which are  characteristic  for
Individual  tissues  and   almost   Independent  of  the species.   The  highest
values   of  manganese  1n  humans   are  found  1n  liver,   kidney and  endocrine
glands.  Manganese has been  shown  to  penetrate  the  blood-brain  and placental
barriers.   Animal  data  Indicate  a higher manganese  accumulation  1n suckling
animals, especially 1n the brain.
    Manganese  elimination from  the  body 1s accomplished mainly  via  feces.
Biliary excretion  1s  predominant under  normal  conditions although excretion
via the pancreas  and  Intestinal wall  are considered  to  be  Important  1n
conditions of  biliary  obstruction or  manganese  overload.   In humans  and 1n
animals urinary excretion 1s low.  The  total body  clearance  of  manganese 1n
humans  can be  described by a curve which 1s  the sum of  at least two exponen-


0201P                                2-6                              5/06/83

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 tlal functions with  half-times  of  4 and 40 days, respectively.  However, the
 physical  significance of  the estimated  half-times  cannot be  obtained from
 this data.
    Manganese metabolism  1s  rigorously controlled by homeostatlc mechanisms.
 The homeostatlc control 1s primarily  exerted  at the level of excretion; how-
 ever,  the  site  of gastrointestinal (GI) absorption  may  also  be an Important
 control  point.    The  absorption,  retention  and  excretion of  manganese are
 Interrelated  and  respond  very  efficiently   to an Increase   1n  manganese
 concentration.  The  GI absorption  depends not  only on   the  amount  Ingested
 and  tissue levels of  manganese, but  also on manganese  b1oava1labH1ty and
 Interaction  with  other metals.   The  Influence  of   tissue  concentrations  on
 the excretory mechanism 1s still unknown.
    It  1s  generally  accepted that  under  normal conditions  3-4% of  orally
 Ingested manganese 1s  absorbed  1n man and other  mammalian species.   Gastro-
 intestinal absorption of manganese  and  Iron may be  competitive.  This  Inter-
 action has a  limited relevance  to  human risk  assessment  under normal  condi-
 tions.  However,  1t  does  lead to the  hypothesis that Iron-deficient  Individ-
 uals may be more sensitive to manganese than the normal  Individual.
 2.2.2.   Toxldty.   The acute toxldty of manganese 1s   greater  for  soluble
 compounds  and  via the  parenteral  route.   Acute poisoning  by  manganese  1n
 humans 1s  very  rare.  Along  with a  number of other metals,  freshly  formed
manganese oxide  fumes have been  reported to cause metal  fume fever.
    The major systems affected  by  chronic exposure  to  manganese 1n  humans
are  the  CNS  and  pulmonary   systems.   The neurological   disorder  known  as
chronic  manganese  poisoning,  or  manganlsm,  resulting  from  occupational
exposures  to manganese dusts  and fumes 1s well  documented.   Earlier  studies
report advanced   cases  of  manganlsm  1n  various miners,  but  more  recent


0201P                               2-7                              5/06/83

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studies report cases  showing neurological symptoms  and  signs at  much  lower
exposure concentrations.
    These  reports  Include  no  longitudinal   studies  and  are therefore  not
adequate to  Identify  a dose-response relationship,  but  do permit  the  Iden-
tification  of  the  LOEL.   The  full clinical  picture of  chronic  manganese
                                                                           3
poisoning  1s  reported  less  frequently  at  exposure  levels  below 5  mg/m .
The reports  of  a few  early  signs  of manganlsm  1n  workers exposed  to  0.3-5
    3                    33
mg/m   suggest  0.3  mg/m   (300  i^g/m )  as  a  LOEL.   The  data  available
                                              3
for  Identifying  effect  levels  below  0.3 mg/m   Is  equivocal  or  Inadequate.
This 1s  further  complicated by  the  fact that good biological  Indicators of
manganese  exposure  are  not presently  available.  Also,  there are  neither
human nor animal data suggesting  the  rate  of  absorption of manganese through
the  lung;  therefore,  extrapolating from other   routes  of  exposure would be
difficult.
    Only  one  animal  study utilized Inhalation exposure  to study neurotoxic-
1ty, resulting  In  no behavioral  effects 1n  monkeys  or rats  after  9 months
                          3
exposure   to   11.6  ug/m   Mn3°4-   Unfortunately,   this  study   did   not
Include  biochemical  data  nor levels  of  manganese 1n brain  tissues  relating
the neurotoxlc effects to the tissue levels of manganese 1n the body.
    Chronic treatment  of rats  with  MnCl   1n the drinking  water  throughout
development 1s associated with  selective regional alteration of synaptosomal
dopamlne  uptake  but  not  of  serotonin  or  noradrenaline uptake.  The  brain
regional  manganese  concentrations  show  dose-dependent  Increases  and  in
treated  animals,  the changes  In  synaptosomal dopamlne  uptake 1s  associated
with  decreased  behavioral  responses  to   amphetamine  challenge.    These
observations  are consistent  with the  hypothesis that  1n  chronic manganese
toxicity  the  central  dopamlnerglc system 1s disturbed,  providing a mechanis-
tic explanation for the extrapyramldal disturbances seen 1n human manganlsm.

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    The  toxic  effects  of  manganese on the  pulmonary  system vary 1n type and
severity.   There  are  several  reports of  humans developing  pneumonia after
occupational exposures  to manganese at  levels  higher  than the present TLV of
          3
5  mg  Mn/m .   Chronic  bronchitis  has been  reported to be  more  prevalent 1n
                                   3                           33
workers   exposed   to  0.4-16  mg/m ,  but   below  0.04  mg/m   (40  ug/ro )
respiratory symptoms were  not  Increased  over controls.  However, conclusions
about  these  exposure/response relationships are limited by  the broad range
of  exposure  values.   Also,  the health  effects  of  simultaneous  exposures to
other  toxic  substances,   such  as  silica,  have  also  not   been  thoroughly
examined.
    One  study  1n schoolchildren  supported  an  association  between Increased
respiratory  symptoms and  exposure to  the  manganese dusts  emitted  from  a
                                    3
ferromanganese  plant at  3-11  v-g/m .   The study  Involved  several  hundred
children,  had  a  participation  rate  of  over  97%  and  clearly  documented
exposure  patterns.   It  1s  plausible  that exposure  to  manganese  may Increase
susceptibility  to  pulmonary disease  by disturbing the normal  mechanism of
lung clearance.
    Inhalation  studies  of  pulmonary  effects  1n animals  show the occurrence
                                                                            3
of  acute respiratory effects  when the  level   of  exposure  exceeds  20 mg/m
of  MnO .  Mice  and  monkeys  exposed to  Mn02  via  Inhalation showed  patho-
                             3
logical  effects  at  0.7 mg/m  after  14 days  of exposure.    This  represents
the  lowest  level at which  adverse  effects were  observed  after  Inhalation
exposure  to MnO  .   There 1s little  data on toxldty  after  chronic exposure
                                             3
to  MnOp  levels  between  0.1  and  0.7  mg/m  .   Several  studies  do  exist
                                              3
where  animals  were  exposed  to  ~0.1  mg/m    MnO  as  Mn30,  particle  or
aerosols  of  resplrable  particle  size,  an   appropriate  form  for  health  risk
evaluation for  airborne manganese.   These  studies have  a  variety  of defi-
ciencies  such  as  lack  of   description  of  pathological  examination,  small

0201P                               2-9                               5/06/83

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study  size  and short  exposure  period.  The  clustering of  negative  results
around  this  level  suggests that major  adverse effects such  as  gross patho-
logical changes are absent.
    Reports  of  Impotence  1n  a  majority of  patients  with  chronic  manganese
poisoning are common,  however, no other  supporting  human  data are available.
Existing  animal  data  addressing   reproductive   failure   1n  males  describe
long-term dietary  exposure to manganese.   Results  show that  dietary levels
up  to   1004  ppm  as  MnS04»7H20   and   up  to  3550  ppm   as   Mn 0   were
almost without  effect  on  reproductive  performance.  However,  these  and other
observations  need  to  be  verified  using  well-defined reproductive  testing
protocols.
    Although  other  effects of exposure  to manganese  have been  reported  1n
animals,  none  have  been observed consistently.   In some  cases  the Implica-
tions  for human health are uncertain.
    Prior to  the adoption  of  the International  Agency  for  Research  on Cancer
(IARC)  criteria,  the  U.S. EPA  Carcinogen  Assessment  Group  judged  manganese
to be a  possible  human carcinogen  based on  the mutagenlc  properties  and the
positive  responses 1n  mice and  rats 1n  two  studies.   However,  the  pathology
was Incomplete  1n  these studies  and no  animal  studies  exist using  long-term
exposure  by  feeding  or by Inhalation.   Therefore,  using  IARC criteria,  the
available evidence  for manganese  carclnogenlclty  would  be rated  as  Inade-
quate  1n  animals and no data are available  for humans,  placing  manganese 1n
IARC Group 3.
    Divalent manganese  1on has  elicited  mutagenlc effects  1n a  wide  variety
of mlcroblal  systems,  probably  by  substitution for magnesium  1on and Inter-
ference with  DNA  transcription.   Attempts  to demonstrate  mutagenlc  effects
of manganese  1n mammalian  systems have failed  to  show  significant activity.


0201P                                2-10                             5/06/83

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Two recent  studies suggest  that excess  manganese  during  pregnancy  affects
behavioral parameters,  but  there 1s  Insufficient  evidence to  define manga-
nese as teratogenlc.
2.3.   CONCLUSIONS
    The effects of  major  concern to humans exposed  to  manganese are  chronic
manganese poisoning  and a  range of pulmonary  effects.   The effects  on  the
CNS are   Incapacitating  and generally  Irreversible  1n  Its fully  developed
                                                                           3
form,   and have been  reported at  manganese exposure  levels  above 5 mg/m .
                                                            3
There  have  been no  reports  of CNS effects  below  0.3 mg/m exposure.   Data
                                      3
1s  equivocal  between  1  and  5 mg/m   but  suggest  decreased  prevalence.
                     3
Studies  below  1 mg/m   report  some signs  of the  disease.   There  1s little
supportive animal  data.
    The pulmonary  effects Include pneumonia  and chronic  bronchitis  at levels
which  are also associated  with  neurological  effects.   An  Increased preva-
lence  of  temporary respiratory  symptoms  and  lower  mean values  on  objective
                                                                           3
tests  of  lung  function were  reported  In  children exposed  to 3-11  v-g/m .
In  comparison,  studies  of  a   smaller  number  of   workers exposed  to  <40
    3
ug/m   resulted 1n the  conclusion that  symptoms  were generally  unrelated
to  exposure to  manganese.    There  are  no  data describing  the effects  of
manganese exposure 1n asthmatics  or  other  sensitive Individuals.
    Animal  studies report  Increased  susceptlblHy  to  Infection and radio-
logical changes 1n  the  lungs associated with  manganese  exposure, thus quali-
tatively  supporting  the  respiratory  effect  as  the  endpolnt of  concern.
Respiratory  symptoms  occurred at lower  levels  than  neurological symptoms  and
are therefore considered to  be the  critical effect.
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              3.  GENERAL PROPERTIES AND BACKGROUND INFORMATION
3.1.   PHYSICAL AND CHEMICAL PROPERTIES
    Manganese 1s a  ubiquitous  element  1n  the earth's  crust, 1n water, and 1n
partlculate  matter  1n  the  atmosphere.   Manganese  was  recognized  as  a  new
element  by  C.W. Scheele,  Bergman and others,  but  1t was  first  Isolated by
J.G. Gahn  1n 1774  on reducing the dioxide  with carbon.   Some ores  have been
known  and  used  since  antiquity,  e.g.,  pyroluslte  (MnO )  1n  glass  bleach-
Ing (Weast,  1980; Re1d1es, 1981).
    Manganese  (Mn)   1s   a  steel  gray,  lustrous,   hard   brittle  metal,  too
brittle  to  be used unalloyed.   It  exists 1n four  allotroplc  forms  of  which
the  a-form  Is  stable  below   710°C.    Manganese  has   only  one  stable
natural  Isotope,    Mn.   The  manganese   atom  1n  the ground  state  has  the
electronic    configuration    (Is2)    (2s2)    (2p6)   (3s2)    (3p6)    (3d5)
   p
(4s )  and  six  possible orientations  of  the  5/2  nuclear  spin  (Matr1card1
and  Downing,  1981).  Some  physical  properties  of manganese  are listed  1n
Table 3-1.
    Manganese exists  In  11  oxidation  states   from -3  to  +7, Including  0,
                                       5   2
since  the   outer  electron  levels,  3d 4s ,  can  donate  up  to seven  elec-
trons.    The  compounds  most  environmentally and  economically  Important  are
those   containing   Mn2*,   Mn4"1"   and   Mn7+.    The   Mn4*   1s   significant
because  of  the  Important oxide,  MnO .  The +2 compounds are  stable  1n  add
solution but  are readily  oxidized  1n alkaline medium.  The  +7  valence  1s
found only 1n oxy-compounds (Re1d1es,  1981).   Normal  oxidation potentials  of
manganese couples are given  1n  Table  3-2.
1797A                               3-1                               4/27/83

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                                  TABLE 3-1
                      Physical  Properties  of  Manganese*
    Property                                              Value

Atomic number                               25
Atomic weight                               54.9380
Density                                     7.43 at  20°C
Melting point                               1244°C
Boiling point                               1962°C
Specific heat                               0.115 cal/g  at 25.2°C
Moh's hardness                              5.0
Solubility                                  Soluble  1n  dilute  adds;  reacts
                                            slowly 1n  hot  or  cold water.
*Source:  Weast,  1980;  Matr1card1  and  Downing, 1981; Re1d1es,  1981
1797A                               3-2                               4/27/83

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                                  TABLE 3-2

              Normal Oxidation Potentials of Manganese Couples3
Oxidation
State


0,
+2,
+2,

+2,

+4,
+4,
+6,

o,
+2,

+2,

+4,
+4,
+6,


+2
+ 3
+4

+7

+6
+7
*7

+2
+3

+4

+6
+ 7
+7
Reaction
Add Solution
0.
Mn^ Mn + 2e
Mn2*^ Mn3+ + e
2+ b +
Mn + 2H~0 ^Mn02(py) + 4H + 2e
2+ +
Mn + 4H?0 ^ (Mn04) + 8H + 5e
2- +
Mn00 + 2H00^(MnO.) + 4H + 2e
c c. 1
Mn00(py)b + 2H00 ^ (MnO.)" + 4H+ + 3e

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3.1.1.    Manganese Compounds.   Manganese  forms  numerous  alloys  with   Iron
(ferromanganese,   slUcomanganese,  Hadfleld  manganese steel)  and with other
metals  like aluminum alloys, aluminum-bronzes, constantan,  manganese-bronze,
Monel,   nickel-silver,   and   nickel-chromium  resistance   alloys.    Several
Important compounds  of  manganese  are  described  below  and  1n  Table 3-3.
    3.1.1.1.    MANGANESE  (I)  COMPOUNDS  —
    3.1.1.1.1.    Methylcyclopentadlenyl   Manganese   TMcarbonyl   (MMT)
CH3C5H4Mn(CO)3  or  MMT  1s   a  light  amber  liquid  added  to  fuels  as  an
antiknock agent  or  smoke suppressant.    It  1s  formed by reaction of  methyl-
cyclopentadlene with  manganese  carbonyl  [Mn  (CO)  _].
    3.1.1.2.    MANGANESE  (II) COMPOUNDS —
    3.1.1.2.1.    Manganous   Carbonate — MnCO   occurs  naturally,  but   the
                                             O
commercial product  1s made  by  precipitation  from  manganese sulfate solu-
tions.   It 1s  used  1n ferrHe production,  animal  feeds,  ceramics, and  as a
source  of add soluble  manganese.
    3.1.1.2.2.    Manganous  Chloride — MnCl   exists   1n  anhydrous  form  and
as hydrate with 6, 4, or 2 water molecules.   It  1s used  as  a  starting mater-
ial for other manganese compounds and  1n anhydrous form as  a  flux 1n  magnes-
ium metallurgy.
    3.1.1.2.3.    Manganese   Ethyleneb1sd1th1ocarbamate   —    (CH  NHCS^Mn
1s a yellow  powder  used  under  the  name of "Maneb"   as  a  fungicide.   It  1s
produced  by  treating  a  solution  of  manganous  chloride  containing sodium
hydroxide  and  ethylenedlamlne with  carbon  dlsulflde and  neutralizing   the
resulting solution with acetic  add.
    3.1.1.2.4.    Manganous     Acetate    ~    Mn(C ^O^ ^4H20    1s     1n
the form  of  pale red,   transparent  crystals.   It 1s soluble  1n water   and
alcohol.  It  1s  used  as  a mordant  1n  dyeing  and  as a  drier for  paints  and
varnishes.

1797A                               3-4                             5/03/83

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                                                                  TABLE 3-3



                                               Physical  Properties of Some Manganese Compounds*



i
Ul




4/27/83
Name and
CAS Registry Valence
Number
Methylcyclopenta- +1
dlenyl manganese
tMcarbonyl (MMT)
[12108-13-3]
Manganous oxide +2
[1344-43-0]
Manganous +2
carbonate
[598-62-9]
Manganous +2
chloride
[7773-01-5]
Manganous +2
acetate
[15243-27-3]
Manganous +2
sulfate
[7785-87-7]
Trlmanganese +2, +3
tetraoxlde
[1317-35-7]
Manganese +4
dioxide
[1313-13-9]
Potassium +7
permanganate
[7722-64-7]
Chemical Molecular
Formula Weight
CH3c5H4Mn(c°)3 218.09
MnO 70.94
MnCOs 114.94
MnCl2 125.84
Mn(C2H302)2 • 41^0 245.08
MnS04 • H20 169.01
Mn304 228.81
Mn02 86.94
KMn04 158.04
Specific
Gravity
1.39(20°)
5.37(23°)
3.125
2.997
(25°)
1.589
3.25
4.64
5.026
2.703
(20°)
Melting Boiling
Point, - Point,
°C °C
1.5 233
1945
Decomposes
650 1190

Decomposes
850
1560
Decomposes
500-600
Decomposes
200-300
Solubility
Insoluble 1n H20. Soluble
1n most organic solvents
Insoluble 1n H20.
65 mg/a (25°C)
Soluble In dilute acid.
Insoluble In NH3 and
alcohol.
622 g/a (10°C)
1238 g/a (100°C)
Soluble 1n alcohol.
Insoluble 1n ether and NH3-
Soluble 1n cold H20 and
alcohol.
Soluble 1n one part cold and
0.6 part boiling water;
Insoluble In alcohol.
Insoluble 1n H20.
Insoluble 1n hot or cold
H20, HN03, or acetone.
Soluble In HC1.
28.3 g/a (0°C)
250 g/a (65°C)
Decomposes 1n alcohol.
Soluble In H2S04.
Very soluble In methyl
alcohol and acetone.
*Source:   U.S.  EPA.  1975; Re1d1es,  1981

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     3.1.1.2.5.   Manganous  Oxide — MnO 1s  found In  nature as  manganoslte
 and  1s  manufactured by  reducing  higher oxides with  carbon  monoxide or coke
 or  by thermal decomposition of  manganous  carbonate.   It  1s a  good starting
 material  for  preparing other manganous  salts  and has some  use 1n ferrltes,
 1n welding, and as a nutrient 1n agricultural fertilizers.
     3.1.1.2.6.   Manganous   Phosphate ~ Mn(PO)    1s   made   from   car-
 bonate  and phosphoric  add.   It   1s  used  as  an Ingredient of  proprietary
 solutions  for phosphatlng Iron and  steel.
     3.1.1.2.7.   Manganous   Sulfate ~  MnSO  »H  0   can  be   made   by  treat-
 Ing  any  manganese  compound  with  sulfurlc  add.  It  Is also a  co-product 1n
 the  manufacture  of  hydroqulnone.   In pure  state 1t  1s  used as  a reagent.
 Its major  use 1s as a nutrient 1n fertilizers and 1n animal feeds.
    3.1.1.2.8.   Manganese   Soaps —  Manganese(II)   salts   of   fatty   acids
 (2-ethyl  hexoate,   Unoleate,  naphthenate,   oleate,  reslnate,  stearate,  and
 tallate) are  used  as catalysts  for   the  oxidation and polymerization of oils
 and as paint driers.
    3.1.1.1.9.   Other   Manganese   (II)   Compounds  —  Other   commercially
 available  Mn(II) compounds  Include  the  acetate,  borate,  chromate,  fluoride,
 formate, gluconate,  glycerophosphate,  hydroxide or  "hydrate", hypophosphlte,
 nitrate, nitrite,  perchlorate,  sulflde, and  sulflte.
    3.1.1.3.   MANGANESE (IV) COMPOUNDS —
    3.1.1.3.1.   Manganese  Dioxide  — MnO   1s  the  most  Important  Mn(IV)
 compound and the most  Important  commercial compound of manganese.   In  nature
 1t  occurs  as  pyroluslte,  the  principal ore  of manganese, as  well  as  1n
 several  other  less  common minerals.  More  than 90%  of manganese  dioxide 1s
 used  1n  the  production of ferromanganese and  other  alloys  and  of  manganese
metal.  The rest 1s  used for the production of dry cell  batteries  and chem-
 icals, and as  an  oxldant 1n the  manufacture  of  some  dyes.

 1797A                               3-6                              4/27/83

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    Manganese dioxide  1s  Insoluble  1n  water.   This property confers  stabil-
ity,  since  the  1on  Mn    1s  unstable  1n  solution.   On  heating,  1t  forms
other  oxides,   Mn 0  ,   Mn 0   and  MnO.    Hydrated  forms   are  obtained   by
                  c. o     o H
reduction of  permanganates 1n  basic  solution.   In  add  solution  1t  1s  an
oxidizing agent.  The classic  example 1s  the  oxidation  of  HC1  which has been
a convenient means of  chlorine  generation both 1n the  laboratory and  1n  the
Weldon process  for manufacturing chlorine commercially (Hay, 1967).
                         Mn02  + 4HC1 -> Mn4tCl4 + 2H20
                          Mn4+Cl4 -* Mn3*Cl3 + 1/2C12
                                   warm
                          Mn3+Cl3 -* Mn2*Cl2 + 1/2C12
    Manganous sulfate  and  oxygen are  produced 1n  hot  sulfurlc add  1n  the
presence of  a little  MnO as catalyst.   Hydrogen  fluoride  reacts  with manga-
nese  dioxide at 400-500°C  to  produce  manganous  fluoride  and oxygen  (Hay,
1967).
    Manganese dioxide can react with sulfur dioxide 1n two ways:
    2.   Alternatively, 1t can occur stepwlse:
                       2Mn0
                           2
                          Mn2(S03)3 -* MnS206 + MnS03
                            MnSOo + 1/20- -> MnSO.
                                O       c.        i
The  end  products  of  this  series  of   reactions   are   Mn$206  (manganese
dlthlonate) and  MnSO.  (Hay, 1967).   Nitrogen  dioxide also  reacts  similarly
with MnOp to form manganous nitrate, Mn(N03)2 (Sullivan,  1969).
1797A                               3-7                              4/27/83

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    3.1.1.4.   MANGANESE (VII) COMPOUNDS —



    3.1.1.4.1.   Potassium  Permanganate — KMnO.   1s   an  Important  Indus-



trial chemical as well  as  an  analytical  reagent (Re1d1es, 1981).  Its use 1s



based on  Us  oxidizing ability.   It  1s  used 1n  the  organic  chemical Indus-



try,  1n  the  alkaline  pickling  process,  and  1n  cleaning  preparatory  for



plating.   It   1s  also  used  for  water  purification  and  odor  abatement  1n



various  Industrial  wastes.   Other permanganates,  although  less  Important,



are also available commercially.



    Manganese  (VII) permanganates  (almost  always  potassium permanganate) are



used  1n a  host  of oxidations  Including  reactions  with both  Inorganic  and



organic compounds (Hay, 1967).   In  moderately alkaline  solution, the oxidiz-


ing reaction 1s:



                      2KMn04 + HO -* 2KOH + 2MnO  + 3(0)



In neutral solution,



        2KMn04 +  MgS04 (buffer)  + H20 -» K2S04 + Mg(OH)2 + 2Mn02  + 3(0)




while 1n add  solution 1t  reacts as



                2KMnO, + 3H0SO,  -» K_SO. + 2MnS04 + 3H.O + 5(0)
                     4     c  4     d  H        4     I


    In  organic  reactions   (Mn04)~  1s  a  most versatile  oxldant, the  activ-


ity of  which  can  be controlled  to  a  great extent not only by the  molecular


nature  of   the  compound  undergoing oxidation  but  also  by  the acidity  or



alkalinity and other reaction conditions.  It 1s  potentially  a more vigorous



oxldant  than dlchromate.



3.2.   SAMPLING AND  ANALYTICAL METHODS



    Determination  procedures  consist  of  three main steps:  sampling,  sample



preparation and analysis.   In trace metal determination,  sample preparation



often also Includes  a  preconcentratlon or a preseparatlon step.
1797A                               3-8                              4/27/83

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3.2.1.   Sampling.
    3.2.1.1.   AIR — Virtually  all  of  manganese  present  1n  air  1s  Inor-
ganic,  1n  the  form  of  suspended  partlculate  matter,  and  1s  collected  by
sampling  procedures  for  airborne partlculates.   Organic manganese compounds
1n  the gas  phase  are not normally  present  1n air  1n  detectable concentra-
tions  (see  Section  3.5.2.1.),  although  sampling and analysis techniques have
been  described  (Ethyl  Corporation,  1972;  Coe  et  al., 1980).   Therefore,
description  of  air  sampling procedures  will  be  limited  to  methods  designed
for partlculates.
    3.2.1.1.1.   In-plant A1r  —  In  the past,  the  1mp1nger  was widely  used
for  the sampling  of  partlculate air  contaminants  (ACGIH,  1958).   However,
owing  to  a  low  efficiency  for  particles  smaller  than 1 urn  1n  diameter
(Davles  et  al.,   1951)  and  Impractical  handling  and  transportation,  the
1mp1nger  has  been  replaced  by  filtering media:   1)  glass fiber  filters,
which  have  a low  resistance to air  flow,  have  high efficiency  for submlcron
particles,  and are  hydrophoblc  so that  they  can  be weighed  without  trouble;
and 2)  organic membrane  filters,  which  are  soluble 1n  organic  solvents and
strong  adds.  Electrostatic  predpHators have also been used  1n  the work-
Ing environment.   They have  a  high collection  efficiency  for  particles  of
all sizes,  but  are less practical  and  versatile 1n field use  than  filters,
and cannot be used 1n potentially explosive atmospheres.
    3.2.1.1.2.   Ambient A1r — High-volume  (HI-VOL) samplers  are  frequent-
ly used  to  collect  samples  of airborne  particles  from  ambient  air  for trace
metal  analysis.  These samplers typically  use glass  fiber filters,  20x25 cm,
                                           3
and collect  particles  from  about   2500 m   of  air  1n  24  hours.   Several
hundred samplers of  this  type are currently  1n use as  part of  the  National
A1r Surveillance  Networks  (NASN),   and  thousands  are  1n use  by state  and
1797A                               3-9                              4/27/83

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 local  agencies  (Thompson, 1979;  U.S.  EPA,  1979a).   Prior  to  1977,  filters

 from  the  NASN were composited  for  analysis on a  quarterly  basis,  but since

 then  Improved  analytical  efficiency   has  enabled   analysis  of  Individual

 filters (U.S. EPA, 1979a).

    High-volume  samplers  with  organic  membrane  filters  of  10  cm diameter,
               3
 sampling  200 m   of  air  over  24 hours,  and  low-volume  samplers with  mem-
                                                    3
 brane  filters  of  2.5 cm  diameter,  sampling 25-30 m  over a week,  have also

 been  used (WHO,   1976;  Sarlc,  1978).  Manganese  can be  conveniently deter-

 mined on  both membranous  and  fibrous filters (Fugas,  1980);  however,  fibrous

 filters should not be used when  the method of analysis 1s x-ray fluorescence

 (U.S. EPA, 1981c).

    Particle size 1s an Important factor  1n determining human  exposure to an

 ambient  aerosol   (see  Section  3.6.4.1.).    High-volume  samplers may sample

 particles  as  large  as   50-100  vim  1n  diameter   (Bernstein et  al.,  1976;

 Thompson, 1979) and thus  do not  provide  any specific  Information on particle

 size.   A  variety  of  samplers  achieving  some  degree  of  particle  size

 discrimination have  been  used  for  ambient  trace metal  analyses,  Including

 cascade Impactors  (Lee  et al.,  1972)  and  cyclones (Bernstein et  al.,  1976;

 Bernstein  and Rahn,  1979).   However,  dlchotomous   samplers  are  now  most

widely  used  for  this  purpose.   Samplers  of  this  type  separate  fine  and

coarse  particles  by  use  of  a virtual  Impactor (Dzubay  and Stevens, 1975).

The fine  particle cut-off (D«-n), at which 50% of larger-diameter  particles

are excluded, ranges  from 2-3.5 v.m depending on the sampler used.   A frac-

 tlonlng Inlet also  1s  often used to determine the upper size limit  for  the

coarse  fraction;  DS(,  1s  normally  set  at  10,  15 or  20  urn  (e.g., U.S.  EPA,

1981a).   Particles for metal analysis are  typically collected on a teflon or
                                                            p
cellulose  filter   of   ~1 vim  pore   size  and   -6-25  cm   surface   area
1797A                               3-10                             4/27/83

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(e.g.,  Lewis and  Madas,  1980;  Dzubay et  al.,  1982).   Flow rates vary  from
14-50  a/m1n,  and  sampling  times  from  2-24  hours  (e.g.,  Stevens  et  al.,
1978).
    3.2.1.1.3.    Stationary  Source  Emissions -- Glass  fiber   filters   are
used for  sampling manganese  particles  1n  stacks,  often  1n  the  form of  a
filter  thimble  to Increase  the sampling  surface and  thus  reduce air  flow
resistance.    For   low  temperature   flue  gases   (=100°C),    membrane   or
cellulose filters may  be  used  as  well.   Sampling Is  usually performed  Iso-
klnetlcally, and  the  filter  holder Is placed  1n the  stack or  heated  during
sampling to prevent  condensation.   In the  classical  sampling   train for  the
collection of particles (36  FR  24876; U.S.  EPA,  1978a),  the filter holder 1s
followed by a series  of  Implngers  for the  collection  of  condensate  1n order
to  measure  moisture  content and  to  protect  the  pump and  the  gas  meter.
Implngers can be replaced  by a condensor.   Cascade Impactors  are available
for  collecting  samples of particles  by  size from  the stack (P1lat et  al.,
1970)  and  are  sometimes  preceded  by  a  cyclone  to prevent  the  massing of
large  particles  on  the first separation stage  (Instrumentation for  Environ-
mental Monitoring, 1975).
     3.2.1.1.4.   Mobile Source  Emissions — Standard  tests of  motor  vehicle
emissions measure only gaseous pollutants (CO,  NO   and  hydrocarbons),  but
for  heavy duty  vehicles,   smoke  measurements  using optical methods  are  also
used (37  FR 24250).   The  only  purpose of  the  filters  1n  the sampling system
1s  to  remove particles from the  gas  stream.   The composition,  mostly   lead
content  and particle  size,   of automotive exhaust  has  been   measured  only
under  experimental  conditions  (Ter   Haar  et  al.,  1972).   The  samples,
collected 1n  large  black  polyethylene bags during a  7-mode Federal  emission
1797A                               3-11                             5/03/83

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 test  cycle,  were diluted 8  to  1  wHh dry air  1n  order  to prevent condensa-
 tion,  and a  known  volume   of  the  mixture  was  sampled  through  a membrane
 filter.
    For  particle  size analysis, either microscopic counting of electrostatic
 predpltator   samples  (Hlrschler   and  Gilbert,  1964)   or  size  selective
 sampling  by  cascade  Impactor was  used (Mueller et  al., 1963).  The samples
 were  collected  from a tailpipe by a  probe  (Ter  Haar  et  al.,  1972) or else a
 mixing tunnel was used for proportional sampling (Hab1b1,  1970).
    3.2.1.2.   WATER  ~ The  sampling  of  water and wastewater can  be  by grab
 or  composite  sample  (minimal  portions  25  mfc).   Samples are  collected  1n
 bottles  of  glass or  plastic (U.S.  EPA,  1973;  King,  1971).   Preparation  of
 bottles  to prevent  contamination  1s  discussed by Moody and Llndstrom (1977),
 and possible wall losses by Bond and Kelly (1977).
    3.2.1.3.    FOOD — According to  the  sampling objective, samples of  food
 consist  of cooked,  raw,  or  packed food.  Plscator  and Vouk (1979) described
 three methods  currently  available for estimating  Intake of metals  via food
 products:
    1.  To collect  and analyze samples  of   single  foodstuffs for  the
        metal, and then estimate the Ingested amount of metal.
    2.  To collect  and  analyze  certain classes  of  food 1n  the amounts
        that  are actually  consumed and make  estimates from that.
    3.  To collect  and  analyze  duplicate  samples  of the  meals  people
        have  eaten during  a  certain period.
    The  first  of  the  three  methods  1s recommended by the  Food and Agricul-
 tural   Organization/World  Health  Organization  (FAO/WHO,  1977);  the  second
method has been used by the  U.S. FDA (1978).
    3.2.1.4.    SOIL  — Samples  of  soil  are  collected  either   area  wide  or
along  a transect.  The variability 1n  the soil  complex makes  1t desirable  to
take paired  samples.

1797A                                3-12                              4/27/83

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    Profile samples are collected  either  by digging a hole at  a  sample site
and taking an undisturbed slice from  the  side  of  the  hole,  or layer by layer
to the  depth  desired.  The  samples are  screened  to  remove  organic  matter,
stones,  and  lumps,  and are  thoroughly mixed.  A  more detailed  description
can be found 1n Bear (1964).
    3.2.1.5.   BIOLOGICAL MATERIALS --
    3.2.1.5.1.   Urine — Samples   of   urine  are  collected  either  1n  glass
(Ajemlan and Whitman, 1969) or polyethylene  bottles (Stoeppler  et al., 1979)
with  the addition  of  redistilled  HC1  at  pH  2,  and  are  kept  under refrigera-
tion  before  analysis.    Preferably,   24-hour   samples  should  be  collected
(T1chy et al., 1971).
    3,2.1.5.2.   Blood -- Samples  of  blood  are obtained  by venlpuncture and
transferred to  polyethylene  tubes.   If  serum  1s  used for  further  analysis,
blood 1s  allowed to clot and  serum 1s  separated by  centrlfugatlon (D'Amlco
and Klawans,  1976).   If whole  blood 1s analyzed,  heparln  1s  added (Tsalev et
al.,  1977).   This,  however, can Introduce contamination  according to Bethard
et al.  (1964),  who used citrate dextrose as  a coagulant.   Additional possi-
ble sources of contamination are discussed by Cotzlas  et al.  (1966).
    3.2.1.5.3.   Tissue  and  Organs — Tissue   or  organ  samples  should  be
dissected  with   knives  1n a  dust-free  atmosphere,  placed  1n  a  polyolefln
vessel,  and stored deep frozen  until analysis (Stoeppler et al., 1979).
    3.2.1.5.4.   Hair and  Other Biological  Samples — Samples  of  hair are
cut close  to  the scalp  (Gibson  and DeWolfe,  1979)  and stored 1n polyethylene
bags.
    Samples of   nails  (Hopps,  1977),  teeth  (Langmyhr  et  al.,  1975),  skin
(Parkinson  et  al.,  1979), and  sweat   (Hopps,  1977) have  also  been  used for
manganese analysis.


1797A                               3-13                             5/03/83

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3.2.2.   Sample Preparation.  While  sampling  1s  rather specific  for  various
environmental media,  the  procedures  for sample preparation and  analysis  are
often  the  same.   Unless a  nondestructive  method  1s used  for  analysis,  sam-
ples have  to be transformed  first  Into  solution  by  dry,  wet,  or  low tempera-
ture ashing and add  digestion.  The  conventional ashing  1n  a  muffle furnace
results  1n  loss  of a number  of  trace elements (Thompson  et al.,  1970),  but
manganese  can  be  treated   by  any  ashing  procedure without  an  appreciable
loss.  After  digestion  of   the samples  with  nitric  add,   the add  has  to be
expelled, and manganese 1n the residue 1s dissolved  1n  hydrochloric add.
    Glass  fiber  filters are  not  destroyed In  the  ashing procedure;  there-
fore,  1t 1s  better  to remove manganese  by add extraction (Thompson  et  al.,
1970)  1n order to avoid filtration which 1s  a  source  of  wall  losses 1n trace
metal  analysis  (Hrsak  and  Fugas,  1980).   Extraction,   with  a  mixture  of
nitric and hydrochloric adds, may  be carried out  by  refluxlng  after  ashing
of  the  sample   (U.S.   EPA,  1979a),  or  by   son1f1cat1on In  the  adds  at
100°C, without  ashing.   The latter  method  1s  currently used  by the  U.S.
EPA (1983a).
    If small  concentrations of  manganese  are  present In a  large  volume  of
sample  {e.g.,  water  or urine),  1t  may  become  necessary  to  Increase  the
concentration of manganese  to  a  measurable  level  by  reducing the  volume  of
the solution by evaporation.  To avoid  contamination,  nonboHIng  evaporation
1n Teflon  tubes  (Boutron  and Martin, 1979)  or "vapor filtration"  through  a
vapor-permeable  membrane  (U.S.  EPA,   1978b) have  been  used.   A  simultaneous
Increase  1n  the concentration  of other  substances  present 1n the  sample  1n
much  higher  concentrations  may  cause  turbidity,   copredpltaton,  or  other
type of  Interference  caused by  the  "matrix  effect."  In such cases  a  pre-
separatlon  step  1s  Indicated.   It  1s   usually  based  on chelatlon,  either


1797A                               3-14                             4/27/83

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 selective,  e.g.,  with  thlnoyltrlfluoroacetone (Sarlc,  1978) or nonselective,
 as  with 8-hydroxyqu1nol1ne  (AJemlan  and  Whitman,  1969;  KUnkhammer,  1980;
 Vanderborght  and Van  Grleken,  1977)  and  cupferron  (Van  Ormer  and   Purdy,
 1973;  Buchet  et  al.,  1976)  or  by  1on exchange  on  Chelex 100  (Lee  et al.,
 1977)  or Dovex  Al  (R1ley and  Taylor,  1968).  Coprec1p1tat1on  with  dlethyl
 dlthlocarbamate  (Watanabe et al.,  1972)   or  d1benzyld1th1ocarbamate  (Under
 et  al.,  1978)   also   has  been  applied for  enrichment  of  samples  as  has
 electrodeposltlon  (Wundt  et  al.,  1979).   Radio-chemical  separation  1s most
 often  used  before the  analysis  of  Irradiated samples  (Cotzlas et al.,  1966;
 Hahn et  al.,  1968; Versleck et al., 1973).
    Samples of  plants, raw food,  or  hair  have to be  cleaned before  further
 treatment.  Care should be taken  not  to   contaminate  the  sample during this
 operation.  Detergents  or  solvents  have been used for  washing hair samples.
 However,  while  surface contamination  1s  being  removed, weakly  bound metals
 also  may be  removed  from hair.   Hair washing  procedures are  discussed  by
 ChHtleborough (1980).
 3.2.3.   Analysis.  The selection  of  available  analytical  methods  for  the
 determination of manganese has  Increased   1n  recent  years,  and methods  of
 preference have changed.
    Some 30 years  ago  colorlmetrlc  (Standard Methods  for  the Examination  of
 Water  and  Wastewater,  1971)   or   spectrographlc  (Thompson   et  al.,  1970)
 methods  were  used  the  most.   Polarographlc methods had  a  number of support-
 ers but  never became  very popular.  Polarographlc and  voltametrlc analyses
 are now  regaining some popularity  since new techniques have  been  developed
with  a  high  resolution  and   sensitivity,  such  as  the  pulsed  stripping
 technique (Flato, 1972).  Colorlmetrlc methods are still  used, especially  1n
water  analysis,  and are now coupled with an autoanalyzer (Crowther,  1978).


 1797A                                3-15                             4/27/83

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    The  Introduction  of  atomic  absorption  spectrophotometry  (AAS)  1n  1955
proved  to  be a  turning point 1n  analytical practice.  Although  many  other
new and  sophisticated methods have been  developed,  none  has  experienced such
a wide  acceptance  as  AAS.  The  Introduction of Delves  cups  (Delves, 1970),
and fTameless  techniques  using  the carbon  rod  (Matousek and  Stevens,  1971)
and  graphite furnace  (Slavln et  al.,  1972),  made  1t  possible  to  analyze
m1crol1ter  samples with   little   or   no  pretreatment,  although  with  less
precision and at a higher  cost.
    DC  arc  optical emission  spectrometry  (OES) was  used  by  U.S.  EPA  until
1976  for  multi-elemental  analysis of  NASN  high-volume  samples  collected  on
glass fiber  filters  (U.S. EPA,  1979a).   The method  currently used  for  this
purpose  1s  Inductively coupled  argon plasma  optical emission  spectrometry
(ICAP)  (U.S.  EPA,  1983b).    Since  Instrumental detection  limits are  lower
than most blank filter  analyses,  the  limits  of  discrimination  are determined
mainly by filter characteristics.  The limit  of discrimination for manganese
on  filters   used  by  the  NASN  1n 1975-1976  was  -0.0025  ug/m3  (U.S.  EPA,
1979a).
    X-ray  fluorescence   (XRF)   1s  also  used  1n   multi-element  analysis
(G1lfr1ch et al.,  1973).   Problems Include  particle  size effect  (Davlson  et
al., 1974),  self  absorption   (Dzubay and  Nelson,  1975),  and the preparation
of standards with  a matrix  matching  that of  the sample.  This method 1s  not
used with  fibrous  filters, but  Is the  most popular  for  use with  membrane
filters, as  are  commonly  used with  dlchotomous samplers.    Detection limits
             2
of  -20  ng/cm   of  filter  surface area  have been  Indicated  for  manganese.
For  a 24-hour sampling  period with typical filters  and flow  rates, detection
limits  of   0.002-0.007  ng/m   In  air  are  obtained  (Ozubay  and  Stevens,
1975;  Stevens et  al.,  1978).
1797A                               3-16                             4/27/83

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    Neutron activation analysis  (NAA) has  been  used  for  the determination of
manganese  1n  various environmental  media,  mostly 1n  multi-element analysis
(Robertson and Carpenter, 1974).   NAA suffers  from Interferences  such as the
production of  the same radlolsotope by  another element or one with  a close
radiation  peak,  but most of  these  can  be eliminated by  optimizing  IrMda-
tlon,  decay,  and counting times.   The  method 1s  sensitive,  but  more costly
and less frequently available than XRF  (U.S. EPA, 1981c).
    Both NAA  and XRF are basically nondestructive methods of analysis,  but
1f a greater  sensitivity  1s required, a  separation and preconcentratlon step
cannot be  avoided for aqueous  samples (Lee  et al., 1977; Buono et al., 1975;
Watanabe et al., 1972; Under  et al., 1978).
    Instrumental  detection  limits  for  manganese by  several  analytical tech-
niques are shown 1n Table 3-4.   Reported  sensitivities for  any  method vary
depending  on  the type  of Instrument,  the  preparation or enrichment  of  the
sample, and on the way  of expressing the result.   It 1s difficult to  compare
the  sensitivities  claimed  by researchers  using  various  methods  since  the
result may be expressed  as  absolute amount,  concentration  per  ml of final
solution,  or  per unit  of measure  of the  medium  from which  the  sample  was
taken.
3.3.   PRODUCTION AND USE
3.3.1.   Production.   The ferroalloy Industry  uses manganese-bearing  ore  to
produce  several  manganese  alloys   and  manganese  metal.   Production   may  be
carried out using a  blast furnace, an  electric arc  furnace  or electrolytic-
ally (Bacon,  1967; U.S.  EPA,  1974;  MatMcardl  and Downing,  1981).
1797A                               3-17                              4/30/83

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                                  TABLE 3-4

                    Relative Sensitivity of Some Important
                     Analytical Techniques for Manganese*
            Analytical Method                      Detection Limit
                                                        (ng)
Neutron activation analysis                             0.005

Optical emission spectroscopy (DC arc)                 10

Atomic absorption spectrophotometry                     0.5

Spark source mass spectrometry                          0.05


'Source:  U.S. EPA,  1975
1797A                               3-18                             4/27/83

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    For blast  furnace production  of  ferromanganese  (an  alloy of  manganese
and Iron)  the  furnace 1s charged with  a  blend of ores, coke  and  limestone,
or dolomite,  and  operated at  low blast  pressures.   The  composition of  the
charge  1s  carefully  controlled  to  decrease  the  slag production,  minimize
dust  losses,  and  allow  uniform gas  distribution  throughout the  furnace.
This 1s done  by  careful  choice of the  chemical composition  of the  charge as
well  as the  size  distribution.   High  manganese  recovery  1s  favored  by:
1) small  slag volume,   2) a  basic  slag,  3)  high   blast  temperatures,  and
4) coarse  ores.   The  limit  of capacity  1s  determined by the  loss  of  manga-
nese by volatilization.   Blast furnace  production of ferromanganese was last
used  1n  this  country   1n  1977;  production   1s  now  primarily  by  electric
submerged-arc furnace.
    In  submerged-arc  furnace production,  the  charge, consisting of  manganese
ore, coke  and  dolomite,  1s  placed 1n the furnace by continuous or  Intermit-
tent  feed.   Vertically   suspended  carbon  electrodes  extend  down   Into  the
charge, and  carbon  reduction of  the  metallic  oxides  takes  place  around  the
electrodes.  Carbon monoxide gas  1s  produced  1n  large  quantities,  and  rises
from  the  charge   carrying entrained  fume particles.   Submerged-arc furnaces
may  have   open  tops,  may be  partially sealed  (mix-sealed),   or  completely
sealed.  The  open  furnaces  vent  larger quantities  of  gas  due to  mixing of
air with the process gases.
    SHIcomanganese  1s   an  alloy of  manganese and  Iron,  also produced  by
smelting  of  ore  1n  an  electric  submerged-arc  furnace.    It differs  from
standard ferromanganese  1n that  the furnace charge  contains  large  amounts of
quartz, and the resulting alloy 1s lower 1n  carbon and higher  1n silicon.
    For electrolytic  production  of h1gh-pur1ty manganese  metal, the  ore 1s
leached with  sulfurlc  add  at  pH 3 to  form manganese  sulfate.  The solution


1797A                               3-19                             5/03/83

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 1s  adjusted to  pH  6  by the  addition of  ammonia  or calcined  ore to preci-
 pitate  the  Iron and  aluminum.   Arsenic,  copper,  zinc,  lead,  cobalt  and
 molybdenum  are removed as  sulfldes  after the  Introduction  of  hydrogen sul-
 flde  gas.   Ferrous  sulflde  and  air  1s  added  to  remove  colloidal  sulfur,
 colloidal metal  sulfldes,  and  organic  matter.   The purified  liquid  1s then
 electrolyzed.
    Manganese  metal  can  also be produced  via a fused-salt electrolysis pro-
 cess.  The  process  Is  similar  to  the Hall method of producing aluminum.  The
 manganese ore  1s reduced to the manganese(II)  level and charged to an elec-
 trolytic  cell  containing molten calcium  fluoride  and  lime.  The manganese 1s
 formed 1n a molten state.
    A  number  of compounds  of managanese  also  are  commercially produced.
 Manganese  oxide   (MnO)  1s   produced  by  reductive  roasting  of  ores  high  1n
 managanese  dioxide  (MnO  ).   MnO 1s  an  Important precursor  of  several  other
 commercially-produced compounds, Including electrolytic  manganese dioxide, a
 h1gh-pur1ty  product  formed  by  electrolysis  of MnO.   Potassium permanganate
 1s  produced by  a  liquid-phase oxidation  of  managanese  dioxide ore  with
 potassium  hydroxide,  followed  by  electrolysis  (Re1d1es,  1981).   United
 States production capacities for several compounds  are shown 1n Table 3-5.
    Manganese  supply-demand  relationships for  the years  1969-1979 are  given
 1n Table  3-6.   A small  proportion  of the manganese smelted  1n  this  country
 Is mined  domestically,  the bulk  1s Imported.   However,  ore   Imports  have
declined recently since  Imports of  alloy and metal  have Increased and  over-
all  demand  for ferroalloys  has decreased somewhat.   Domestic  production  of
ferromanganese  has  declined  steadily since  1965;  slUcomanganese production
has  also declined recently  (Table  3-7).
1797A                               3-20                             5/03/83

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                                   TABLE 3-5

                  Estimated United States Production,  Capacity
                    and Use of Selected Manganese Compounds*
    Product
                                       Estimated
                       Formula      U.S.  Production
                                    Capacity (mt/yr)
                        Use
Electrolytic man
ganese dioxide

High purity man-
ganese oxide
 Manganese  sulfate
 Potassium per-
 manganate
                        MnO
 60% manganese  oxide     MnO
                       MnS04
 Manganese chloride     MnCl2
                       KMn04
18,000


 9,000




36,000




68,000



 3,000



14,000
Methylcyclopenta-      CH3C5H4Mn(CO)3  500-1,000
dlenyl manganese
trlcarbonyl (MMT)
 Dry-cell  batteries;
 ferrltes

 H1gh-qual1ty ferrltes;
 ceramics; Intermediate
 for high  purity Mn(II)
 salts

 Fertilizer; feed addi-
 tive, Intermediate for
 electrolytic manganese
 metal and dioxide

 Feed additive; ferti-
 lizer; Intermediate for
 many products

 Metallurgy; MMT synthe-
 sis; brick colorant;
 dye; dry-cell batteries

 Oxldant;  catalyst; In-
 termediate; water and
air purifier

 Fuel additive
*Source:  Adapted from Re1d1es, 1981
1797A
                                   3-21
                                                                     4/27/83

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                                                                             TABLE 3-6


                                                         Manganese Supply-Demand Relationships,  1969-19793
                                                              (thousand short tons, manganese content)
OJ
 i
ro
co
03


Mine production:
United States
Rest of world
Total

Domestic mines
Shipment of Government
stockpile exceses
Imports, ore
Imports, alloy and metal
Industry stocks, Jan. 1
Total U.S. supply
Distribution of U.S. supply:
Industry stocks, Dec. 31
Exports, ore
Exports, alloy and metal
Demand
1969


93
9.192
9,285

93

50
992
257
1.180
2,572

1,241
10
4
1.317
1970


66
8.978
9,044

66

140
847
238
1.241
2,532

1,175
10
20
1,327
1971


38
9.960
9,998
Components
38

118
938
212
1.175
2.481

1,281
25
5
1,170
1972
World

29
9.983
10,012
1973
Production

31
10.707
10,738
and Distribution of
29

218
793
305
1.281
2.626

1,241
12
7
1,366
31

242
722
336
1.241
2.572

978
29
11
1,554
1974


35
10.185
10,220
U.S. Supply
35

807
593
376
978
2,789

1,183
107
7
1,492
1975


19
10.791
10,810

19

309
766
346
1.183
2,623

1.359
125
6
1,133
1976


31
11.007
11,038

31

294
649
478
1.359
2,811

1,373
64
10
1,364
1977


27
9.547
9.574

27

358
454
481
1.373
2,693

1.092
69
9
1,523
1978


38
9.544
9,582

38

279
278
604
1.092
2,291

811
100
17
1.363
1979


31
10.487b
10,518b

31

264
244
708
811
2,058

749
29
30
1.250
U.S. Demand Pattern
Construction
Transportation
Machinery
Cans and containers
Appliances and equipment
011 and gas Industries
Chemicals
Batteries
Otherc
Total U.S. primary demand
268
253
185
62
51
43
37
20
398
1,317
260
226
176
73
51
42
37
20
442
1,327
252
261
175
71
51
46
35
19
260
1,170
236
239
171
58
51
44
50
18
499
1,366
325
340
229
72
68
63
54
18
385
1.554
317
315
245
79
68
69
65
18
316
1,492
249
260
185
59
47
64
52
16
201
1,133
238
298
186
63
51
53
47
18
410
1,364
240
300
188
60
53
63
61
18
540
1,523
279
317
216
60
58
74
61
18
280
1,363
291
296
217
61
59
70
59
17
180
1,250
          aSource:  DeHuff and Jones, 1980

          Estimated

          clncludes processing losses

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                                  TABLE 3-7

                         Net United States Production
                    of Ferromanganese and S1l1comanganesea
      Year
  Ferromanganese
(103 short tons)
 SlUcomanganese
(103 short  tons)
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
(120)b
193
189
317
273
334
483
576
544
683
801
760
835
852
880
941
946
1148
929
751
781
733
843
(75)b
173
188
165
142
120
129
143
196
184
153
165
193
223
284
246
253
--
203
152
136
120
101
aSource:    U.S.   Bureau  of  Mines  (Jones,  1982;  DeHuff  and  Jones,   1981;
 DeHuff,  1961-1980)

Estimated gross  production;  exceeds net  production  (U.S.  Bureau of  Mines,
 1983)
1797A
       3-23
           4/27/83

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 3.3.2.   Use.   The  principal   use  of  manganese  1s  1n  metallurgy,   which
 accounts  for  =95%  of  United  States  demand  for  all   forms  of  manganese
 (Re1d1es,  1981)  and =99%  of manganese  alloys  and metal  (DeHuff  and  Jones,
 1981).  The majority (>90%)  of  metallurgical  use 1s  1n steel production, for
 which  manganese  1s  1nd1spens1ble   (Matr1card1   and   Downing,  1981;  Bacon,
 1967).  Its function 1s  3-fold:   1)  1t  combines  with sulfur, eliminating the
 principal cause  of  hot-shortness;  2)  1t acts as  a deoxldlzer  or  cleanser 1n
 molten  steel;  3) 1n certain steels  1t  1s  used as   an  alloying  element  to
 Improve  the   strength,   toughness,   and  heat-treating   characteristics  of
 structural and engineering steels.
    Several  different  manganese  alloys,  as  well as h1gh-pur1ty  manganese
 metal, are used  to  Introduce manganese Into  steels,  pig Iron,  and some non-
 ferrous alloys  (Bacon, 1967).  The  various  forms are listed  1n  Table 3-8,
 along with their composition and use.
    A minor  use  of manganese metal,  1n various powdered  forms,  1s  1n mili-
 tary  and  civilian  pyrotechnics  and  fireworks.   It   1s  used to  produce ex-
 tremely  bright  flares  and  lighting  devices.   Annual  consumption  for  this
 application may be on the order  of several  hundred tons per year.
    A variety  of compounds  of  manganese are  used 1n the  chemical  Industry
 and  battery  manufacture;  these uses  accounted  for  4.7  and  1.4%  of  total
 United States manganese demand  1n 1979  (see  Table 3-6).   Some major  uses are
as  follows:    feed  additives  and  fertilizers  (MnO, MnSO,),  colorants  1n
                                                            4
brick and  tile  manufacture  (various  oxides,  MnClp),  dry  cell  battery manu-
facture  (electrolytic   MnO,,, MnClp),   chemical  manufacture  and  processing
 (KMn04,  MnC03,  MnCl2)  and fuel additives (MMT) (see Table 3-5).
    MMT was  Introduced  1n  1958  as   an  antiknock fuel  additive   (U.S  DHEW,
1962).  This  compound  has  been  used  at a concentration  of  0.025  g Mn/gal  1n


1797A                               3-24                             5/03/83

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ID
~J
3>
                                                                            TABLE 3-8

                                                                  Commercial Forms of Manganese3
                      Name
      Composition^
                                                                                                                   Use
          High purity manganese
 i
M
VI
          Low-carbon ferromanganese
          Medium-carbon ferromanganese
          Standard ferromanganese
          Low-Iron ferromanganese
          Splegelelsen
99.5X manganese
 0.15X (max) hydrogen
 0.030X (max) sulfur
 0.005% (max) Iron
 0.005X (max) carbon
 0.001X (max) phosphorus,
  aluminum, silicon
 CO
 to
95-90X manganese
 2.OX (max) silicon
 0.07-0.75X carbon
 0.2% (max) phosphorus
 0.02X (max) sulfur

80-8SX manganese
 1.25-1.SOX carbon
 l.OX (max) silicon
 0.3X (max) phosphorus
 0.02X (max) sulfur

78-82X manganese
 up to 7.5X carbon
 1.2X (max) silicon
 0.35X (max) phosphorus
 0.05X (max) sulfur

85-90X manganese
 7X carbon
 3X silicon
 2X Iron

16-19X manganese
 6.5X carbon
 1.0-3.OX silicon
 0.08X (max) phosphorus
 0.05X (max) sulfur
Ferrous metals:
  free-machining steels
  flat-rolled low-carbon steels
Non-ferrous metals (Improves strength, ductility and hot-rolling
properties)
  aluminum alloys
  aluminum-bronze
  constantan
  monel
  everdur
  nickel-chromium
  nickel-silver
  manganese-bronze for ship propellers

Stainless steels where low carbon content 1s essential
For use In steels with carbon specifications too low to permit use of
standard ferromanganese
Used 1n production of Bessemer, open-hearth and electric furnace steels
for forging, rolled products, and castings
Used 1n making alloys with non-ferrous metals such as aluminum, nickel,
and copper.
A white cast  Iron with  low phosphorus and  sulfur, used for making alloy
additions and as a cleaning agent.

-------
                                                                         TABLE 3-8 (cont.)
 us
 •—i
                      Name
                                           Compos1t1onb
                                                                                                                   Use
 VjO
 I
 S3
          "MS" ferromanganese
          "DQ" ferromanganese
          Exothermic ferromanganese
          Ferromanganese-slllcon
SHIcomanganese
          Calclum-manganese-slHcone
          Manganese-aluminum
            master alloys
                                     80-85X manganese
                                      1.25-1.SOX carbon
                                      0.35X silicon

                                     86X manganese
                                      0.45X carbon
                                      0.40X silicon
                                      0.17X phosphorus
                                     63-66X manganese
                                     28-30X silicon
                                      0.08X (max)  carbon
                                      0.05X (max)  phosphorus
65-68X manganese
18.5-21X slllcone
 1.SOX carbon
 0.2X (max)  phosphorus
 0.04X (max) sulfur

53-59X silicon
16-20X calcium
14-18X manganese

75X manganese
25X aluminum
                                  Used for  making screw-stock where high silicon content destroys
                                  machining properties.
                                  Used as a manganese additive to steels for drawing quality steel sheets.
Briquets when added to steel cause an exothermic reaction—used for
ladle additions of manganese to prevent chilling.

For partial slag reduction and manganese additions 1n the production of
the 300 series of stainless steels, for large manganese additions to the
200 series of stainless steels, and 1n nongraln-orlented silicon
electric steels and low-carbon, low-alloy steels as a ladle addition of
manganese and silicon.

Used In open-hearth steelmaklng practice as a blocking agent (I.e., to
prevent the reaction between carbon and oxygen) for engineering steels
with carbon content of 0.10-0.15X.
                                                                       In  high  quality  steel  castings  to  Improve  tensll  strength,  elongation,
                                                                       and Impact  strength.
                                                                       Used  1n aluminum alloys  to  Impart  strength,  hardness,  and  stiffness.
PO
          aSource:  Bacon, 1967 and OeHuff, 1975

          ^Composition  Is  given for  Grade A product;  other  grades will  have the  same  Impurities, but  1n  a higher  percentage.   The balance of  each
           composition necessary to make 100X 1s mainly Iron.
CO
CO

-------
 fuel  on  and 0.08-0.5 g  Mn/gal  In  turbine  fuels,  and  has been  used to  a
 small  extent 1n  leaded  gasoline  (Ter Haar et  al., 1975).  Production  prior
 to 1974  was =500  tons/year  (=125  tons Mn/year)  (P1ver, 1974).   Beginning
 1n 1974, MMT was  used 1n  unleaded  gasoline  at concentrations  up  to  0.125  g
 Mn/gal;   use  1n  1977  has   been estimated  at -12,000 tons/year  (-3000 tons
 Mn/year)  (Vouk  and  P1ver,  1983).   Some adverse  effects  of MMT on  catalytic
 converter performance  and  hydrocarbon  emissions  were  reported  (U.S. EPA,
 1977b),  and MMT  use  In  unleaded  gasoline was  banned  1n  October,  1978.  The
 ban continues 1n  effect,  except  that MMT  use  at  0.031  g/gal  was  permitted
 during  a 4-month period 1n 1979,  due to a shortage  of  unleaded  fuel   (44 FR
 32281-32282).   MMT  continues  to  be  used  1n  =20%  of  leaded  gasoline  at
 levels  of =0.05 g Mn/gal,  and 1s  used 1n Canada  1n  the  majority of  unlead-
 ed gasolines at  levels  of up to 0.068  g  Mn/gal  (Hall,  1983).   Options for
 Us future  use  at low levels  1n United  States  unleaded gasoline continue to
 be studied  (Hall, 1983).
 3.4.   SOURCES OF MANGANESE  IN THE ENVIRONMENT
 3.4.1.    Crustal  Materials and Soils.   Manganese  1s  widely distributed  1n
 the earth's  crust.   It  1s considered to be  the 12th most  abundant element
 and fifth most  abundant metal.   The  concentration  of  manganese  1n various
 components  of the  earth's  crust  ranges from  near  zero to 7000  ug/g-   A
 rough  estimate  of  the average  concentration  of  manganese  1n  the earth's
 crust  1s  about  1000  mg/kg (DeHuff,  1973).   Tureklan and  Wedepohl  (1961)
 suggested  the  following distribution  of  manganese, expressed  1n  ug/g,  for
 the major units  of the earth's crust:
    1.   Igneous  rock:   ultrabaslc,   1620; basaltic,  1500;  hlgh-caldum
        granitic,  540; low-calcium  granitic,  390;  and  syenltlc,  850
    2.   Sedimentary  rock:   shales,   850;  sandstones,  essentially  zero;
        and carbonates, 1000
    3.   Deep-sea  sediment:   carbonate,  1000; and clay, 6700

1797A                                3-27                              4/27/83

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 Hodgson  (1963)  reported concentrations  of  manganese 1n  ug/g  for  various
 types  of rocks and  for  soil:   1000  1n  earth's  crust; 2000  1n  basic rocks;
 600  1n add rocks; 670 1n sedimentary rocks; 850 1n soils.
     Manganese  1s  a major  constituent  of  at least 100 minerals and an access-
 ory  element  1n more  than 200 others  (Hewett,  1932).   The most common manga-
 nese minerals  and the percentages of manganese  contained therein are listed
 1n Table 3-9.
     Relatively  little  manganese  1s mined  within the  United  States   (S1tt1g,
 1976).   Manganese deposits  are  well-distributed through  the  southern  Appa-
  i
 lachlan  and  Piedmont regions,   the  Batesvllle  district of  Arkansas  and  many
 of the western  states. These deposits  have been  exhausted 1n terms of mining
 for  profit  at existing  or  appreciably  higher prices.  There  are  large
 low-grade  manganese  deposits extending  for miles  along  both  sides of  the
 Missouri River  1n South  Dakota and  large  low-grade deposits 1n  the Cuyuna
 Range  of  Minnesota,  1n the   Artillery   Mountains  region  of  northwestern
 Arizona,  1n   the  Batesvllle district of  Arkansas,  1n  Aroostok  County  1n
 Maine,  and to  a  lesser  extent  1n  the Gaffney-K1ngs  Mountain district  of
 North  Carolina  and   South  Carolina.  Manganese  ore (>35%  Mn)  1s no longer
 mined  1n the  United  States, but  some manganlferous ore  (5-35% Mn)  1s  mined
 1n Minnesota, New Mexico  and South Carolina (DeHuff  and Jones,  1980).
    Researchers  report  various  concentrations  of  manganese  1n  different
 types of soils.   Swalne  (1955)  reported a  range of 200-3000 y.g/g  for  total
 content  of  manganese  1n  most   soils.   Wright et al.  (1955)  studied virgin
 profiles of  four  Canadian  soil  groups  and  reported  a manganese  content  of
 250-1380 ug/g.   Swalne and  Mitchell  (1960) studied representative  Scottish
 soil  and reported a  range for   total  manganese  of  50-7000 ug/g 1n  a1r-dr1ed
soil.  Shacklette et al.  (1971)  analyzed  various soil  samples  1n  the United


1797A                               3-28                              4/27/83

-------
                                  TABLE 3-9



                   Manganese Content of Selected Minerals*
Mineral
Pyroluslte
Manganlte
Hausmannite
RodochrosHe
Rhodonite
BraunHe
Pyrochrolte
Alabandlte
Formula
Mn02
MnO(OH)
Mn304
MnC03
MnS103
3Mn203, MnS103
Mn(OH)2
MnS
Manganese Content (%)
60-63
62
72
47
42
63
61
63
*Source: Hewett, 1932
1797A
3-29
4/27/83

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States  and  reported  a  range  of  manganese content  from <1-7000 ug/g,  with
an arithmetic mean of 560 v.g/9-
    Crustal  materials  are  entrained  Into  the  atmosphere  by  a  number  of
natural  and  anthropogenic  processes, and  thus compose  an  Important  fraction
of atmospheric  partlculate.    These  processes  Include  vehicle  suspension of
road  dusts,  wind erosion and  suspension  of soils  (especially  through agri-
culture  or construction activities),  and  quarrying  processes  (Dzubay et al.,
1981).   The  resulting,  mechanically-generated aerosols  consist  primarily of
coarse  particles (>2.5 \im)  (Dzubay,  1980).   Since  manganese  1s a typical
constituent  of   these dusts,   some  researchers  have  used  this  element  as  a
tracer  to determine the  degree  of  contributions  from   these sources  1n
ambient aerosol   (Klelnman et al.,  1980; Knelp et al., 1983).
    Several other processes also  result  1n the  ejection of crustal  materials
to the atmosphere; for  example, the  smelting  of  natural ores  and the combus-
tion  of  fossil   fuels.  However,  these differ  from the above  categories 1n
that much of the material 1s released 1n  the form of fume or  ash 1n  the fine
particle  range   (<2.5  y.ro).   In   addition,  these tend  to  be point  sources
subject  to  control   measures,  whereas the above typically  are not.   These
Industrial and combustion processes will  be  discussed  In  Section 3.4.2.   The
relative  contributions  of  all sources  to  fine  and  coarse  partlculate  1n
ambient air will  then be discussed Section 3.4.3.
3.4.2.   Industrial  and Combustion  Processes.   Manganese  1s  released  to the
atmosphere during  the  manufacture  of ferroalloys,  Iron  and  steel,  other
alloys,  batteries,  and  chemical   products.   Combustion  of fossil fuels  also
results  1n release.   Emissions from these sources  1n  1968 were estimated by
the  U.S.  EPA  (1971),  as  shown   1n  Table  3-10.    This   national  Inventory
estimated  that  nearly  half  of all  Industrial  and  combustlve  emissions  of


1797A                               3-30                              4/27/83

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                                                                         TABLE 3-10
                                             Sources and Estimated Atmospheric Emissions of Manganese 1n 1968a
30




v-o
VjJ







43.
CO
CO
Partlculate
Product/Process Emissions
(kg/mt product)
Mn metal/
electrolytic
Ferromanganese/
blast furnace
Ferromanganese/
electric furnace
SlUcomanganese/
electric furnace
Pig Iron/blast
furnace
Steel/open hearth
furnace
Steel/basic oxygen
furnace
Steel/electric
furnace
Cast Iron/cupola
furnace
Melding rods
Nonferrous alloys
Batteries
Chemicals and
miscellaneous
Mining
Coal combustion
Residual fuel oil
NA
205
NA
NA
75
4-10.5
23
3.5-5.5
11
NA
NA
NA
NA
NA
40-70
NA
Average or Control
Partlculate Predominant Efficiency
Mn Content Particle Size or Prevalence
(X) (vun) of Use (X)
NA
15-25
20-25
(33X Mn Oxide)
NA
0.5
0.5
3.2
(4.4X Mn304)
3.1
(4X MnO)
2
NA
NA
NA
NA
NA
0.02-0.03
NA
NA
0.3
<2
NA
NA
0.5
0.5-1.0
<5
NA
NA
NA
NA
NA
NA
NA
NA
NA
95
NA
NA
97
40
97
78
25
NA
NA
NA
NA
NA
75
10
Mn Emission Factor
(kg/mt product)
2.5
2.1
12
35
0.011
0.026
0.022
0.039
0.165
8b
6b
5b
5»
O.lb
0.0042
NA
Estimated 1968
1968 Volume Emissions
(103 mt product) (mt)
24
481
279
109
80,700
59.000
43,500
14,500
1 5 . 200
2.7b
9.1b
16. 3b
54b
43. 5b
462,000
669x10 bbl
295
1010
3330
3780
910
1506
962
562
2510
21.8
54.4
81.6
270
4.4
1950
6.4
Percent of
Total Emissions
1.7
5.9
19.3
21.9
5.3
8.7
5.6
3.2
14.5
0.1
0.3
0.5
1.6
N 0.03
11.3
0.04
aSource:  Adapted from U.S. EPA, 1971
bOn a basis of tons manganese, not tons product
NA = Not available

-------
manganese  were from  ferroalloy  manufacture,  over  one-third were  from Iron
and  steel  manufacture, about  one-tenth  were  from fossil  fuel conbustlon, and
minor  amounts  (<2%)  were  generated  by other  processes.   Since  1968,  pro-
cesses,  control  measures,  and production  volumes  have  changed substantially
1n many  categories.   Thus  the  emissions estimates  1n Table 3-10 will be used
only  as  a  basis  for  discussion;  more recent  emissions  estimates  are not
available.   The  most  Important  sources  are  discussed  1n  the  following
sections.
    3.4.2.1.   FERROALLOY   MANUFACTURE — The   manufacture   of   manganese
alloys and metal  has  been the  major  source  of  manganese emissions  to the
atmosphere  (see  Table   3-10),  and  has  been  responsible  for  the  highest
recorded  ambient  manganese   concentrations   (see  Section  3.6.1.2.).   Dust
varying  from  3-100 um  1n  size  1s  emitted from crushing,  screening,  drying
and  mixing of  both  raw materials  (-0.3%  loss) and product  (-0.5% loss),
but  the   majority  of  pollution  1s  from  the  furnace  (U.S.  EPA,  1981b).
Furnace  partlculate   emissions  contain  15-25% manganese,   primarily  1n  the
form of  oxides.   Silicates are a  second major constituent.  Particle size 1s
predominantly fine (<2 v.m).
    Total  U.S.  emissions  of  manganese   from  ferroalloy  manufacture  were
estimated  at  -8400 mt  1n  1968  (see  Table 3-10)  but  current emissions  are
probably  much  lower.   Production of ferromanganese  and  slUcomanganese, the
major emission  source,  has declined substantially;  combined  1981  production
was -31% of 1968  production,  and  1982 production estimates  showed substan-
tial  further declines  (see Table 3-7).   Process emissions of manganese may
also  be much lower than  those  Indicated 1n  1968.   Blast  furnaces,  reportedly
the most  prolific  polluter of  any metallurgical process when  not  controlled
(Wurts,  1959),  have not  been used since 1977  (Matr1card1 and Downing, 1981).


1797A                               3-32                             4/30/83

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In  addition,  more  recent  measurements  Indicate  lower  emission  factors  for
controlled submerged-arc  facilities  (Table 3-11).   Ambient  air measurements
In  the  vicinity  of ferromanganese manufacturing  Indicate  that  recent manga-
nese  levels  were  lower  by about an  order  of magnitude than  those recorded
during the mid-1960s (see Section 3.6.1.2.)-
    3.4.2.2.    IRON AND  STEEL MANUFACTURE — There  1s  considerable  loss  of
manganese 1n  Iron  and  steel  production.  Manganese  1s  lost  to  fume,  slag or
other waste products at  each  stage of production; however, the most signifi-
cant  loss 1s  to  fume and slag 1n the furnace.  Partlculates from the furnace
tend  to  be submlcron  1n  size.  Table  3-10  Indicates that  partlculate manga-
nese  content  (<5%) Is less  than for  ferromanganese manufacture,  but  total
emissions are comparable  because of  the  larger production volume.   Other
sources  (U.S. EPA,  1981a)  have listed a higher manganese  content (8.7%)  for
aerosol  from a  steel   electric  furnace  (see  Section  3.4.3.).   Manganese
emissions  1n 1968 were estimated  at  -6500  mt,   or  -37% of  total  U.S.
emissions (see Table  3-10).   Production levels have decreased  somewhat;  pig
Iron  production  1n 1980  was  78% of  1968  levels, and 1980  steel production
was 85% of 1968  levels  (DeHuff, 1961-1980;  OeHuff  and Jones,  1981).
    3.4.2.3.    FOSSIL  FUEL  COMBUSION — Manganese  1s  emitted  to the atmo-
sphere  by the  burning  of coal  and  other  fuels  containing  natural  trace
levels  of  manganese.   The  use  of  manganese fuel  additives constitutes  an
additional source.   The  average and  range  for  mang/artese  concentration  1n
various fuels and  preparations are shown 1n  Table 3-12.   The range  of manga-
nese content  1n  coal ash  1s presented 1n Table 3-13.
1797A                               3-33                             5/03/83

-------
 US
 —J
 3>
                                                                              TABLE 3-11

                                   Estimated Manganese Emissions  from Controlled Submerged-Arc Furnaces Producing Manganese  Alloys
Furnace Type
Open
Open
\jj Open
-e-
Seml-sealed
Semi-sealed
Semi -sealed
Totally sealed
Product
slllcomanganese
slllcomanganese
high carbon
ferromanganese
slllcomanganese
high carbon
ferromanganese
high carbon
ferromanganese
slllcomanganese
Control Type
scrubber
scrubber
scrubber
scrubber
scrubber
scrubber
scrubber
Control Efficiency
(X)
99.1
94. Ob
97
>99.1b
>99.1b
98b
NA
Partlculate
Emission Factor
(kg/mt product)
0
3
0
0
0
0
0
.73
.25
.79
.05
.03
.16
.062
Manganese
Emission Factor
(kg Mn/mt product)
0
0
0
0
0
0
0
.15
.65
.16
.010
.015
.08
.012
U
U
U
U
U
U
U
Reference
.S.
.S.
.S.
.S.
.S.
.S.
.S.
EPA,
EPA.
EPA,
EPA.
EPA,
EPA,
EPA,
1971
1971
19816
1971
1971
1981b
1979b
          aAssumes manganese content of partlculate Is 20X.

          bDoes not Include losses during tapping of the metal.
rsj
-j

co
CO

-------
CD
                                                 TABLE 3-12


                                Manganese Concentrations of Coal, Fuel 011,
                             Crude 011,  Gasoline, Fuel Additives and Motor 011*
co
 I
CO
in
 IV)
 CO
 CO
Samp 1 e
Coal
Residual fuel oil
Crude oil
Regular gasoline
Brand A
Brand B
Premium gasoline
Brand A
Brand B
Fuel additives
Gas treatment
Fuel-mix tune up
Engine tune up
Gas power booster
Gas treatment
Gasoline antifreeze
Gas booster
Carburetor tune up
Motor oil
Number
of Samples
76
20
20
10
9
10
8

3
3
3
3
3
3
6
3
4
Average
Concentration
37 ug/g
0.136 ug/g
0.031 ug/g

-------
                                  TABLE 3-13
                        Manganese Content in Coal Ash*
               Type of Coal                     Range of Content
                                                      (X)
          Pennsylvania Anthracite                 0.005-0.09
          Texas, Colorado, North                  0.01 -1.0
            and South Dakota
          West Virginia                           0.012-0.18
          Montana                                 0.33
          Alabama                                 0.04-0.05
*Source:  Abernathy et al., 1969
1797A                               3-36                             4/27/83

-------
    Coal combustion was  estimated  to be the  source  of  -11% of total manga-
nese emissions  1n 1968  (see Table  3-10).   The emission  factor  assumed  an
average  manganese content  of  26.4  ug/g  1n  coal,  and penetration  to  the
atmosphere of -1654 (U.S. EPA, 1971).   U.S. consumption of coal 1n 1980  was
640.4x10  mt,  an  Increase  of  -39%  over  1968  (Energy  Information Adminis-
tration,  1980).   However,  recent measurements  from  coal-fired power plants
equipped  with  electrostatic predpHators  (ESPs)  showed  manganese penetra-
tions of  0.07-0.13%  for  one plant,  and 1.6%  for another plant with  partial
ESP malfunction (Ondov et al., 1979).   Estimates of  average  penetrations  for
the range of plants currently operating  are not  available.
    While collection  efficiencies may be high,  some evidence  Indicates  that
metal concentrations  are  higher  1n  the  smaller-diameter particles which  are
less efficiently  collected.  Analyses  of  s1ze-fract1oned  fly-ash collected
from a  coal-fired power  plant  predpHator showed that manganese  concentra-
tions were  highest  (1090-1180  ug/g)  1n  particles  of  0.2-1.5  um,   whereas
concentrations   of 500-800  ug/g were  found  among   particles  of   3  to   >140
urn  (Smith et  al., 1979).   A  similar  trend  but with  lower  concentrations
(150-470  ug/g,  Increasing  as  particle  size  decreases)  was  found  1n   air-
borne material  not retained by a cyclonic predpUator  In  another  coal-fired
power plant (Davlson  et  al.,  1974).   The elemental   mass median diameter  for
manganese  for   the  two  ESP-equ1pped plants  described  above  was -2.3  um
for  the more-efficient  and  -8.2 u"" for  the less-efficient  ESP  (Ondov  et
al., 1979).
    The manganese  content  of petroleum  1s  lower by >2 orders of magnitude
than that  of  coal  (see  Table  3-12).   Therefore,  regardless  of  changes  1n
residual fuel  oil  combustion and emission  control  practices,  oil  combustion
constitutes  a minor source  of ambient manganese.


1797A                              3-37                            4/30/83

-------
     P1ver  (1974)  reported that MMT  production prior  to  Us  use In unleaded
 fuel  was  -500  tons/year,  or  -125  tons  as  manganese.    Vouk   and  P1ver
 (1983)  estimated  that 1n 1977, during MMT  use 1n unleaded  fuels,  20% of the
      9
 110x10   gallons  of  gasoline consumed  contained MMT  at  0.125  g  Mn/gal, or
 -3000  tons as manganese.   Estimates  of the  percentage  of  manganese emitted
 from the  tailpipe  range  from 15-30%  of the amount burned (Ethyl Corporation,
 1972;  Plerson et  al, 1978),  resulting  1n  an estimate  of  450-900  tons of
 manganese  emitted  per  year  during the  peak  of  MMT use.  The  manganese 1s
 emitted  primarily  as  Mn 0 ,   1n particles  of  0.30-0.38  vim  mass  median
 diameter  (Ethyl  Corporation,  1972).   The  manganese content  of partlculate
 from two automobiles  burning gasoline  containing  MMT (at  0.125 g/gal) ranged
 from 1.4-3.1%, and averaged  3.0% (Ethyl Corporation,  1973).   Current  use of
 MMT  at  -0.05  g  Mn/gal  1n  -20% of  leaded  gasoline (Hall,  1983)  results 1n
 a substantially lower emissions estimate than  that given for 1977.
 3.4.3.    Relative  Importance  of  Manganese  Sources  at  Several  Locations as
 Determined  by Mass   Balance  and  Enrichment  Models.   The  availability of
 Increasingly  sensitive  analytical techniques  for determining  the  elemental
 composition of  ambient airborne  partlculate matter has  enabled the  use of
 statistical methods to Identify the most  likely  emission  sources.   Elemental
 composition patterns  for  ambient  partlculates at a  "receptor"  or  monitoring
 site can  be  compared with  known or  statistically constructed composition
 patterns  for   particles   from  a  number   of  sources.   Using  chemical  mass
 balance  techniques,   the  total  ambient  aerosol   mass  and the  mass of  each
element at  the receptor  can  then be  apportioned among  the  sources  (Cooper
and Watson, 1980;  Alpert  and  Hopke,  1981;  U.S.  EPA,  1981a).   The  separation
of  coarse  (e.g.,  >2.5  vim)  and  fine  particle  fractions by  a  dlchotomous
1797A                               3-38                             4/27/83

-------
sampler can result 1n better resolution of  sources  (Ozubay,  1980;  Alpert and
Hopke,  1981).   Many  applications  of  source  apportionment  techniques  have
Included data on manganese.
    In  the  Portland  Aerosol Characterization  Study,  a  priori  determination
was  made  of  the  elemental  composition  of  aerosols  from  several  sources
(Table  3-14)  (Cooper  and  Watson,  1980;  U.S.  EPA, 1981a).   The  manganese
component  varied  from  173  mg/g,  for ferromanganese  furnace emissions,  to
"0 mg/g",  for   leaded  automobile  exhaust.   The  elemental  compositions  for
several sources  (soil,  road  dust,  asphalt production,  rock  crusher  and coal
fly  ash)  were  so similar that  they  could not readily be  distinguished; the
manganese  concentration  of  these  aerosols   varied  only  from  0.3-2  mg/g
(Cooper and Watson, 1980).
    Dzubay  (1980) used  six  source  terms for  apportioning Regional  A1r Pollu-
tion  Study  (RAPS) data from dlchotomous  samplers 1n  St.  Louis,  Missouri.
Some  of the  terms  used were  composites,  representing  several natural  and
anthropogenic processes which could  not be  distinguished.   The crustal-shale
component Included soil or  dust  suspended by  wind or  human activities (e.g.,
vehicle   traffic,   earth-moving,  argrlculture,   etc.),   partlculates  from
quarrying  or  other  manufacturing  processes,  and/or  fly ash.   The  crustal-
Hmestone component  Included suspended calc1um-r1ch  soil,  cement  dust from
vehicles  or  cement manufacture, and/or  other manufacturing  processes.   The
term  for  steel   Industry  emissions  might   also  have   Included  natural  or
anthropogenic suspension of  Iron-rich soil.   The  elemental  compositions for
source  aerosols were  assigned  a^ priori.  based on  data  from various studies.
The  manganese  component of  each source,  and  the estimated  contribution of
each  source  to  ambient manganese  and total  aerosol mass  are given  for the
coarse  particle  fraction  at  one  St.  Louis  receptor   site  (site  106)  for


1797A                               3-39                              5/03/83

-------
                                  TABLE 3-14
       Manganese Concentration 1n Fine (<2.0 vim) and Coarse  (2.0-20 urn)
          Particle Fractions of Aerosols from Several Sources 1n the
                   Portland Aerosol Characterization Study*
Aerosol Source
Marine
Soil
Road dust
Leaded auto exhaust
Residual oil combustion
Distillate oil
Vegetative Burn 1
Vegetative Burn 2
Kraft recovery boiler
SulfHe recovery boiler
Hog fuel boiler
Aluminum processing
Steel electric furnace
Ferromanganese furnace
Carborundum
Glass furnace
Carbide furnace
Asphalt production
Rock crusher
Coal fly ash
Mn Concentration
Fine Particles
NR
2.0
1.23
0.0
0.46
0.14
1.2
0.47
0.3
0.54
5.1
0.11
87
173
0.35
0.021
0.42
2.0
0.8
0.3
(mq/q)
Coarse Particles
0.0
0.85
1.0
0.0
0.46
NR
1.2
0.47
5.2
0.54
2.9
0.0
87
173
0.29
0.031
0.36
NR
NR
NR
*Source:  U.S. EPA,  1981a;  Cooper and Watson, 1980
NR = Not  reported
1797A
3-40
4/27/83

-------
 August  and  September,  1976 (Table 3-15).   Dzubay  et al. (1981) used similar
 source  terms  1n an analysis of  data  for  January,  1979, from a single dlcho-
 tomous  sampler  1n Denver,  Colorado.   These  source apportionment  data for
 both  fine  and  coarse  particle  fractions  are also  shown  1n Table  3-15.  A
 comparison  of  coarse  particle  sources  for the  St. Louis  and  Denver   sites
 shows   that  the  proportion  of  manganese  contributed  by  the  crustal-shale
 source  was  much  greater  In  Denver,  1n the absence  of  the  paint pigment and
 steel  sources found 1n  St.  Louis.   Comparison of  fine and coarse fractions
 1n  Denver  shows that while crustal-shale was  the  predominant source of  man-
 ganese  1n coarse particles,  vehicle  exhaust evidently was  the main manganese
 source  1n fine  particles.
    Hopke and coworkers  (Alpert and  Hopke, 1981;  L1u  et  al.,  1982) applied
 target  transformation  factor  analysis (TTFA)  to  other subsets  of  the St.
 Louis RAPS  data.  In TTFA, source aerosol  composition  1s  determined through
 both a  priori  knowledge  of  source  characteristics  and a posteriori selection
 and adjustment  based on factor  analysis  and chemical  element  balance   tech-
 niques  applied   to  the  receptor  data  set.   These  source  refinement  methods
 were applied  Individually  to  fine  and coarse data  sets at  RAPS site 112 for
 July and  August,  1976  (Table  3-16,  part A),  and  to  all  10 St.  Louis   RAPS
 sites  during  a  single  week  beginning July  31,   1976  (Table  3-16,  part 8)
 (Alpert and Hopke, 1981).
    A direct  comparison  of  the TTFA  results with  those of  Dzubay  (1980) for
 St. Louis 1s  not  possible  since  the  same  data  sets were not used.   The stud-
 ies evidently detected differences 1n  aerosol sources  among  the sites.   Site
 106 (see Table  3-15) and several of  the other  sites  (Table 3-16,  part B) are
 located In  close  proximity  to  Iron  works  and foundries,  whereas  site 112
 (Table  3-16, part A) 1s  not.   These differences are  reflected 1n  the absence


1797A                               3-41                              4/27/83

-------
N>
                                                                            TABLE 3-15
                      Manganese Concentration  1n  Aerosols  from Various Sources, and Estimated Percent Contribution  of  Each  Source  to  Observed
                                                       Ambient Manganese and Total Aerosol Mass at Two Sites
Source
FINE PARTICLES**
Ammonium sulfate
Motor vehicle exhaust
Crustal-shale6
Crustal-Hmestone6
Road salt
Refuse Incineration
COARSE PARTICLES'1
Ammonium sulfate
Motor vehicle exhaust
Crustal-shale8
Crustal-Hmestone6
Paint pigment
Steele
Road salt
Refuse Incineration
Mn 1n Source
Aerosol (mg/g)

0.0
0.6
0.85
1.1
0.0
0.7

0.0
0.6
0.85
1.1
4.0
31.0
0.0
0.7
St. Louis. MO RAPS
Contribution to Ambient
Aerosol Mass (X)c

NR
NR
NR
NR
NI
NI

7.1
4.5
51.5
29.4
3.4
1.9
NI
NI
Site 106a
Contribution to
Ambient Mn (X)c

NR
NR
NR
NR
NI
NI

0.0
2.9
34.3
25.7
8.6
48.6
NI
NI
Denver. CO SHeb
Contribution to Ambient
Aerosol Mass (X)c

15.8
25.3
2.2
0.5
1.1
0.2

0.4
7.3
54.0
2.5
NI
NI
10.9
0.6
Contribution to
Ambient Mn (X)c

0
80
20
0
0
0

0
5.6
66.7
5.6
NI
NI
0
0
          aDer1ved from Dzubay,  1980
          bOer1ved from Dzubay et al.,  1981
          Percentages may not sura to 100X when model  under- or overestimates Mn concentration or aerosol mass.
          dSt. Louis study:  fine <2.4 vm, coarse 2.4-20 vn.   Denver  study:  fine <2.5 urn. coarse 2.5-15 um
          ^Composite of natural  and anthropogenic sources; see text
          NI » Not Included In analysis for  this site;  NR = not reported
00
OJ

-------
                                                        TABLE 3-16
ID
~J
3>
                  Manganese Concentration  In  Aerosols  from Various  Sources,  and  Estimated
                    Percent Contribution of Each  Source  to Observed Ambient  Mn and Total
                       Aerosol  Mass,  Based on Target Transformation Factor Analysis.3
                  Source
                                     Mn  1n  Source
                                    Aerosol  (mg/g)
                   Contribution to Ambient
                      Aerosol Mass (%)
                      Contribution to
                      Ambient Mn (X)b
                                  A.   RAPS Site  112, St.  Louis, MO,  July  and  August,  1976
CO
I
CO
FINE FRACTION (<2.4 urn)

Motor vehicle
Sulfate
Fly ash/Soil
Paint
Refuse Incineration
Unknown

COARSE FRACTION (2.4-20

Soil
Limestone
Sulfate
Paint
0.0
0.0
0.7
4.8
8.6
 NR
                                                 0.8
                                                 1.6
                                                 1.0
                                                 1.2
15
65
11
 1
 4
 4
                             54
                             27
                             12
                              7
 0.0
 0.0
13.5
11.8
64.7
  NR
                           38.5
                           38.5
                           10.3
                            7.7
 oo
 CO
                                  B.   10 RAPS Sites,  St.  Louis,  MO,  Week of July 31,  1976
FINE FRACTION (<2.4 vm»)

Sulfate
Steel
Motor vehicle
Zinc/Lead smelter
Unknown
0.0
7.1
0.7
0.8
 NR
84
 7
 6
 2
 1
 0.0
83.3
 6.7
 4.2
  NR

-------
10
                                                     TABLE  3-16  (cont.)
                  Source
                                     Hn 1n Source
                                    Aerosol (mg/g)
Contribution to Ambient
   Aerosol Mass (X)
Contribution to
Ambient Mn (X)b
        COARSE  FRACTION  (2.4-20 urn)
Son
Steel
Limestone
Sulfate
Soil/Fly ash
Unknown
1.1
23.0
0.0
1.7
0.0
NR
31
5
39
11
10
4
21.7
75.0
0.0
11.3
0.0
NR
CO
I
-p»
.£»
aDer1ved from Alpert and Hopke, 1981

Percentages do not sum to 100X because model  slightly under- or overestimated Mn concentration.

NR = Not reported
00
CO

-------
 of  a  resolvable  steel  source at the latter site.  However,  the refinement of
 sources  by  TTFA  results  1n certain Irregularities where a minor element  such
 as  manganese 1s  concerned.   The  attribution  of coarse-fraction manganese to
 a  sulfate  source  term  (Table 16)  was  acknowledged  by  the authors  to be
 Irregular.   This result may  be a sampling artifact  (I.e.,  due to condensa-
 tion  of  SOp  on  coarse Mn-conta1n1ng  particles) or may  result  from "source
 lumping"  due to an Inability  to resolve  other minor, manganese-containing
 sources.   The absence of  manganese  from  the  limestone  and  soil/fly  ash
 source  terms (Table 3-16,  part 8)  1s  also rather  Implausible,  and further
 Indicates the deficiencies of  this  technique.
    In source apportionment  studies  of partlculates  1n New York City, manga-
 nese  was used as  a tracer  for suspended  dust and soils  (Klelnman  et  al.,
 1980;  Knelp et   al., 1983).   Regression models  were  used  to derive coeffic-
 ients  relating  tracer  mass  1n  ambient air to  mass  of partlculates from the
 traced source.   Other  sources which also undoubtedly contributed to airborne
 manganese,  such  as  vehicle   emissions,  fuel  oil burning,  and Incineration,
 were  traced by   other  elements.  Since  the manganese  concentration  1n  dust
 and soil probably  1s relatively stable,  changes 1n the manganese coefficient
 over  time are probably related (Inversely) to  changes 1n  relative contribu-
 tions from  nonsoll-related sources.   From the  period 1972-1973 to the period
 1977-1978,  the manganese  coefficient  ( +  S.E.)  for  total  suspended partlcu-
 late  (TSP)   Increased  from   4204-200  to  840+311,  Indicating a  substantial
 reduction of  manganese emissions  from nonsoll  sources.   These changes  would
 be  expected  due  to  the  elimination of MMT usuage 1n  unleaded  gasoline  and
 reduction of  Incineration  during  this  period  (Klelnman et  al.,  1980;  Knelp
 et  al.,  1983).    A concommltant  reduction  1n  mean  TSP  from  82+2 to  54+2
    3
v.g/m   was    seen   during   this    period.    However,  during  the   period


 1797A                                3-45                             4/30/83

-------
1979-1980,  a  decrease  1n  the  manganese  coefficient  to  670+160 seemed  to
Indicate  Increasing  nonsoll   contributions,   and   was   accompanied   by  an
                                 3
Increase 1n mean TSP to 66^2 iig/m  (Knelp et al., 1983).
    A  simpler  method for  making Inferences  about  partlculate  sources  from
receptor data  Is  by the use  of an  enrichment factor  (EF) model.   The ratio
of  the concentration  of  the  element  1n  question  to that  of  a  reference
element  1s  compared  for  an  ambient  aerosol  and  a  background aerosol  or
source material,  to determine whether  the  element  1s enriched  with  respect
to  the  reference  element  (Cooper and  Watson,  1980).  The crustal  contribu-
tion of manganese to ambient  aerosols  has  been  evaluated  using aluminum as a
crustal reference element,  as  follows:
                                        (Mn/Al)  a1r
                          Crustal  EF =
                                       (Mn/Al)
                                               crust
Values for elements arising exclusively from crustal material  should  be near
unity, although  some  variation  would be  expected  due  to  natural  variations
1n  soil  (see  Section 3.4.1.).   As mentioned  previously, crustal  material
suspended  by  natural  processes  1s Indistinguishable  by  these methods  from
crustal material  suspended  by  human activities.  However,  values  of  crustal
EF  for  elements  such as  lead,  which  are highly  enriched from  noncrustal
                                  4
sources,   may  be  as  high  as  10   (Bernstein  and  Rahn,  1979;  Lewis  and
Madas, 1980).
    Ouce  et  al.  (1974)  reported a  crustal  EF  of 2.6 for  manganese  over  the
Atlantic   Ocean  north  of  30°N.   Bernstein  and  Rahn  (1979)  reported  the
elemental  composition  of  fine  (<2.5 um) and  total aerosol  from New  York
City for  August,  1976.   They  derived  a crustal  EF for manganese  of  4.6,  and
also reported  EF  values  of  5.7,  0.56 and  0.54  for Philadelphia,  Bermuda  and
Tucson, respectively.   Although the latter two  values were lower  by  a factor
of 10, manganese was not considered to  be enriched  1n  the New York aerosol.

1797A                               3-46                             4/27/83

-------
 However,  these  EF  values were based on  total  aerosol  analyses.  Calculation
 of  EF for  the  fine  particle  fraction alone  gives  a value  of 14.3,  or  =3
 times higher.
    Bernstein and  Rahn  (1979)  used a  crustal  Mn:Al  ratio of 0.011  to calcu-
 late  crustal  EF for  manganese.   Very  similar ratios  are found by  examining
 the "crustal-shale" composition  data used  by  Dzubay  (1980) and Dzubay et al.
 (1981),  and the soil,  road dust  and  rock-crusher aerosol  composition data
 reported  by Cooper and  Watson (1980).   Using  this  ratio as a crustal refer-
 ence,  the  EF model  was  applied to dlchotomous  sampler  data sets  for  St.
 Louis,  MO  (Stevens  et   al.,  1978;  Dzubay,  1980; Alpert and  Hopke,  1981),
 Charleston,  WV  (Stevens  et  al., 1978; Lewis  and Madas,  1980), Denver,  CO
 (Dzubay  et  al., 1981),   Houston,  TX  (Dzubay et al., 1982)  and several other
 cities  (Stevens  et al.,  1978).   Crustal  EF for  the coarse aerosol fraction
 (the  lower  size   cut-off  varying from  2.0-3.5  urn)  ranged  from  0.35-4.76
 with  an  unweighted mean value of 1.9.   For  the  fine  fraction, values ranged
 from  1.83-38.8, with  a  mean of  14.4.  The  ratio  crustal EF (fine fraction):
 crustal  EF  (coarse fraction),  ranged  from 2.02-28.9,  with  a mean  of  8.1.
 Thus,  1t  can be Inferred  by  this rough Illustration  that manganese  1n coarse
 aerosol  fractions  tended to be  associated  with  aluminum  1n  ratios  found  1n
 crustal  material.   Lower relative concentrations  of  aluminum  1n fine frac-
 tions  Indicated a  greater Influence  of noncrustal manganese  sources  1n fine
 than In coarse particles In ambient aerosols.
    The  above  conclusions   were  reached   based  on  data  sets  which  were
averaged  over time and/or  local  geography.  However, a single  sample  from
one St.  Louis site (RAPS site  108)  strongly Influenced  by  steel processing
showed an  EF  for   the coarse  fraction  (16.9)  slightly greater  than  that  for
the fine  fraction  (15.6)  (Dzubay,  1980).   Therefore,   Industrial  processes


1797A                                3-47                              4/27/83

-------
may be  expected  to  have  local  Influence on  manganese  levels 1n  the  coarse
particle fraction,  but  this  Influence  1s likely  to  be less  pervasive  than
fine  fraction  enrichment,  due  to the  more   rapid  deposition of  the  larger
particles (Klelnman et al.,  1975).
3.5.   ENVIRONMENTAL FATE AND TRANSPORT PROCESSES
3.5.1.   Principal  Cycling  Pathways  and  Compartments.    Garrels  et   al.
(1975) presented  the  pre-human  cycle and the present-day  cycle  of manganese
(Figure  3-1).  Manganese, an  element of  low  volatility,  tends to settle out
near  sources of pollution and to  be  of  concern  1n local or regional environ-
mental  problems.   However,  fine  partlculate  materials  containing manganese
can  be   distributed  world-wide.   According   to  Garrels et  al.   (1975),  the
major exchange  of manganese between  the atmosphere and  the pre-human earth
surface  was  due to  continental  dust  being swept Into the atmosphere by winds
and  then falling  back  onto  the  earth's surface.  Today  this  dust  flux 1s
augmented  by manganese  emitted  to  the  atmosphere In  partlculate form by
Industrial activities.  The total river  flux  of manganese to  the ocean today
1s  estimated to  be nearly  three times  the  pre-human  flux.   This Increase
represents  principally  an  Increase  1n  the  rate  of  stripping  the  land's
                            14
surface  from  about  100x10   g/year  pre-human  to  today's  rate of  about
      14
225x10    g/year.   Because  this   Increase  1n  stripping  reflects  an Increase
1n  the  load  of  suspended  solids  to  rivers from deforestation  and agricultur-
al  activities,  and  because manganese  1s concentrated  1n  the  ferric oxide
coatings on  suspended  material  and   1n  the suspended  particles,  the land-to-
ocean manganese flux  Is  higher  today than 1n  the past.  Manganese  1n partlc-
ulate emissions from Industrial  activities rivals  the  natural Input  of  con-
tinental dust  to  the atmosphere.  Most  partlculate manganese probably falls
out of the atmosphere near  Industrial sources.
 1797A                               3-48                              5/03/83

-------
us
                                       PRE-MAN CYCLE
                             PRESENT DAY CYCLE
/ /
LAND
0000000
RIVERS
572
»
OCEANS
38000
	 I 	
CO
I
US
                                                   VOLCANISM

                                                 HATC ALTERATION
                                                     SEDIMENTATION
                                                        615
                                    SEDIMENTS

                                   I LOSS OK))  V
                                                    aEDIMENTAIION
                                                      (6)7
                                             VOtCAMSM

                                           MAFIC ALTERATION
                                                  FLUXES  Kf g yr' ;   RESERVOIR MASES   »°g
00
CO
           FIGURE 3-1

The Global  Cycles of  Manganese

Source:   Garrels et al.,  1975

-------
    The  mining  of manganese  ore  has  resulted  1n  a net  gain for  the  land
reservoir and a  net  loss from the sediment  reservoir.   There  Is  no evidence
of change over time  1n  dissolved manganese  1n the oceanic reservoir (Garrels
et al., 1975).
3.5.2.   Atmospheric Fate and Transport.
    3.5.2.1.   CHEMICAL  FORMS  PRESENT IN THE ATMOSPHERE — Soils,  dust  and
other  crustal  materials  containing  naturally-occurring  manganese compounds
enter  the atmosphere as  a  result of  natural  and anthropogenic  processes (see
Section  3.4.1.).   While  a  number  of  ores  exist  (see  Table  3-9),  the  most
common forms  of  manganese 1n  rocks  and soils are oxides  and  hydroxides,  of
oxidation states  +2, +3 and +4,  and manganese  carbonate (Hem, 1970).   These
are undoubtedly  the  most common manganese  compounds 1n  the coarse partlcu-
lates of crustal  origin.   Like soils,  these  particles  usually  contain  manga-
nese at concentrations  of  <1 mg/g  (<0.1%) (see  Section  3.4.1.  and Tables 14,
15 and 16).
    The manganese  emitted by  metallurgical  processes   Is  normally described
as consisting of  oxides (see  Section 3.4.2.).  Manganese  from combusted MMT
1s  emitted   primarily   as  Mn.,0.   (Ethyl  Corporation,   1972).   Much  of  the
partlculate   released from these processes  Is  1n  the  fine  range  (<2.5  v-m).
Fine partlculate  from  fly ash usually  1s no more highly  enriched 1n  manga-
nese than are soils, but the fine particles  arising from metallurgy and MMT
combustion  are  enriched, with manganese  concentrations  ranging  from  14-250
mg/g (1.4-25%) (see Sections 3.4.2.,  3.4.3.  and Tables  3-10 and 3-14).
    Minute amounts of  organic  manganese compounds may  be  present  1n ambient
air under certain conditions.  Ethyl  Corporation  (1972) analyzed  the exhaust
products  of  three cars operating  on  gasoline containing  an abnormally  high
level   of  MMT (1.25 g  Mn/gal).   About 0.1-0.5%  of the  manganese  burned was


1797A                               3-50                             4/27/83

-------
emitted In organic  form.   However,  these authors found  that  MMT was  rapidly
photodegraded  to  Inorganic manganese  1n sunlight;  estimated half-life  was
10-15  seconds.   They  estimated  that,   for  cars   meeting  1975  emissions
standards and  an  MMT use  rate  of  0.125 g Mn/gal, ambient  MMT concentration
would  be  0.12-0.48  ng   MMT/m3  (0.03-0.12  ng  Mn/m3)  1f  photodegradatlon
                                      a                  3
were  neglected,  and  <0.048 ng  MMT/m   (<0.012  ng  Mn/m )  1f  photodegrada-
tlon were considered (Ter Haar  et al., 1975).
    Coe et al.  (1980) used gas  chromatography-atomlc absorption  spectrometry
to measure MMT  levels 1n  air 1n  Canada,  where  MMT Is still  1n use 1n  unlead-
                                                     3
ed  fuels.   With a  detection  limit  of  0.1  ng MMT/m  ,  they  were  unable  to
detect  MMT   1n  samples   of auto  exhaust  from  unleaded  gasoline  (emission
                                                               3
control  system unspecified).   With  a limit  of  0.05  ng MMT/m  ,  they  could
not detect MMT  on  Toronto streets.   MMT detected 1n an  underground car park
                           3
at  levels  of 0.1-0,3 ng/m was  presumed to arise  from fuel  evaporation  or
spillage, rather than exhaust  emissions (Coe et al.,  1980).
    3.5.2.2.    ATOMSPHERIC  REACTIONS  —  Except  for  the  photodegradatlon  of
MMT,  very  little  Information  1s  available on  the  atmospheric  reactions  of
manganese.   Manganese  dioxide  can  react  with  sulfur  dioxide   or  nitrogen
dioxide  to  form  manganous  sulfate  (MnSO.)   and   dlthlonate  (MnS_0,)   or
manganese  nitrate   [MnfNO,,)-],  respectively  (Hay,   1967;  Schroeder,   1970).
Various  oxides  of  manganese   (MnO,  Mn-O,,,  MnO^),  used  as   absorbants,
have  been shown  to combine with sulfur  dioxide  1n  heated  flue  gases  (B1en-
stock and Field, 1960).    The possibility of  these  reactions occurring  In  the
atmosphere has  been  recognized  (Sullivan,  1969;  P1ver,  1974)  but occurrence
or reaction  rates  have not been  demonstrated.
1797A                               3-51                              4/30/83

-------
     It  has  been  shown  that aerosols  of  manganous sulfate can  catalyze the



 oxidation  of  atmospheric  sulfur  dioxide  to sulfur trloxlde,  thus  promoting



 the  formation  of sulfurlc  add  (Matteson et  al.,   1969;  Sullivan,  1969;



 P1ver,  1974):



                                MnSO,      +2H-0
                                    4         2

                      2S00 + 00	-2SO,,	^2H0SO,
                         c    i.          3         24




 It  has  been reported that  under  foggy conditions, an  atmospheric  manganese



 concentration  of  0.2  ug/m3 and  a  sulfur  dioxide   concentration  of  1750


     3                                                                   3
 ug/m  would  result  1n a  sulfurlc  add  formation   rate  of  25  ug/m /hr,



 or a conversion  rate of 1.4%/hr (Bracewell and  Gall,  1967;  Sullivan,  1969).



 Extrapolations from  the experimental  data of Matteson  et al.  (1969)  suggest


                                            3                  3
 that  at  concentrations  of  259   ug  S02/m  and  2  ug  Mn/m  ,  a  rate  of



 ~0.04%/hr would  be observed  (Wright et al., 1973).



     A test  was  conducted to determine the  catalytic effect  of  exhaust prod-



 ucts from  a car  burning MMT-conta1n1ng  fuel  on the disappearance of  SO,, 1n



 ambient air (Wright  et  al., 1973).  In the absence of  manganese, at  a rela-



 tive  humidity  of  90-100%  and  an  S02  concentration  of   35  ug/m3,  the



 rate constant  for S02  disappearance  was  14%/hr.  This unusually high  rate



was  attributed primarily to  1mpact1on  on  the  black polyethylene bag  In which



 the  experiment   was  conducted.    Addition  of  exhaust  to give  a  manganese

                         o

concentration  of 4  ug/m ,  a  level  much higher  than normally  encountered



 1n ambient  air   (see  Section  3.6.1.),  did  not  noticeably affect this  rate,



although  manganese   concentrations   >30   ug/m3  did   Increase  the   rate



constant.    On  the other hand,  addition  of  20  ug/m   of  ammonia, an  amount



probably about  equal  to the  ammonia already present  1n  ambient urban  air,



caused   the  rate  constant   to  double.   The  authors  concluded  that  ambient



ammonia  was  therefore  the rate-controlling  factor  for  SO   oxidation,  and
1797A                               3-52                             4/30/83

-------
that addition of MMT  to  gasoline would have no  measurable  effect.   However,
this conclusion with respect to manganese  1s weakened  by  the apparent magni-
tude of the  container  effect,  and because the control  contained  no exhaust,
rather than manganese-free exhaust.
    3.5.2.3.   DRY   AND  WET  DEPOSITION -- Atmospheric  partlculate  matter,
Including manganese,  1s  transported  by  air  currents  until  1t 1s  lost  from
the atmosphere by either  dry or wet  deposition.
    Dry deposition rate  1s  strongly affected by particle size.   Klelnman et
al. (1975) studied the deposition of  nine  metals 1n  New York City.   Particle
deposition  velocity  was   calculated  by comparing  the  amount  deposited  with
the air  concentration  Immediately above the collection  surface.   Deposition
velocity was  lowest  (1.1  cm/sec)  for lead, which  was  mainly associated  with
small   particles  [mass  median  aerodynamic  diameter   (MMAD)  =  0.56  urn].
Manganese had the highest velocity  (10.4 cm/sec),  and  a larger particle  size
(MMAD =  1.3 \an).  Dry deposition of  manganese  at three New  York City sites
                         ?                                           2
averaged   300-670   ng/cm /month  and   ranged    from   24-1700  ng/cm /month.
Assuming  total  transfer  of partlculates  to  runoff,  dry deposition resulted
In  an estimated manganese  concentration  In urban  runoff  of 39  vuj/i.  or
about 120 kg/day discharged to New York Harbor  (Klelnman et  al., 1975).
    By comparison,  average wet deposition  of manganese  In New York  reported-
                 p
ly  was  120  ng/cm /month,  stemming  from  a rainfall  concentration  of 19  ug
Mn/8,  (Volchok  and  Bogen, 1973).  Thus,  manganese deposited  1n dustfall  was
more than twice that In rainfall.
    Manganese  deposition  1n  precipitation at  ~30  stations  throughout  the
U.S.  In  September  1966-January  1967  was   reported by  Lazrus  et  al.  (1970).
                                                         p
Amounts  deposited  ranged  from  undetectable  (<10 ng/cm /month),  for Mauna
1797A                               3-53                             4/30/83

-------
Loa,  Hawaii;  Amarlllo,   Texas;  and  Tampa,  Florida  to  levels  of  200-300
     2
ng/cm /month  for  Chicago,  Illinois   and   Sault   St.  Marie,  Michigan.   An
                                    2
unusually  high  value  of  540  ng/cm /month  was observed 1n  Caribou,  Maine.
The  latter  dty 1s  located  1n AMstook County, an  area of low-grade manga-
nese  ore  deposits.   The  average  value  was  -80  ng/cm2/month,  and  the
average  manganese  concentration  In   precipitation  was  -12  ug/8.  (Lazrus
et al., 1970).
    None of  the above measurements was  made 1n the  Immediate  vicinity of a
major  Industrial   source.   Dry  deposition  of  manganese was  measured  1n  a
1965-1966  study  of  air  pollution  1n  the  Kanawha Valley,  West  Virginia
(NAPCA,  1970).    In  the   two  communities  nearest  a ferromanganese  plant,
                                                      2
manganese  deposition averaged  19,300 and  2700 ng/cm /month,  respectively.
                                                                           2
Deposition  1n  other  locations  1n the  valley  ranged   from 80-320  ng/cm /
month (see Section 3.6.1.2.).
3.5.3.   Fate and Transport 1n Water and Soil.
    3.5.3.1.   CHEMICAL   FORMS   IN  SOLUTION -- The  aqueous  chemistry   of
manganese 1s complex, as  manganese  can  be  present  1n II, III, IV, VI and VII
oxidation states.  Mn(II) and  Mn  (IV)  are  the oxidation  states  most commonly
found.   In  neutral and add  aqueous  solutions, the  II  state exists  as  the
hexaquo  1on,  [Mn(H20)6]* ,  which  1s  unstable with respect  to  oxidation
by 02  over  the entire pH  range  of natural  water  (Morgan,  1967).   The maxi-
mum concentration  of  soluble Mn*   In  many  natural waters  Is limited  by the
solubility  product of  MnC03.    With   low  alkal1nH1es   and reducing  condi-
tions 1n freshwaters,  solubility may be  restricted by   high  sulflde  concen-
trations.
    The possible chelatlng Influence of natural organic  compounds 1n  natural
waters  was   studied  on   a  hypothetical  multlmetal,  mult1-!1gand  system.
1797A                               3-54                             4/30/83

-------
Calculations were  performed  simultaneously by  Morel  and  Morgan  (1972)  and


by Stumm and  B1l1nsk1  (1972), and  both  concluded that a free  manganese  Ion


may  be  present  as a  predominant  species  even  1f  complex-forming  organic


matter 1s present.


    In water  or  soil  of pH  >8  or 9,  the  soluble divalent manganese  1on 1s


chemically  oxidized to the Insoluble tetravalent  form.   At  pH  <5.5,  chemical


reduction of  the tetravalent  form  takes  place.   However,  the  Interconverslon


of these forms which  1s  commonly observed at Intermediate  pH  occurs  only by


microblal mediation (Alexander,  1977; Konetzka,  1977).


    Groundwater  has  different  manganese  equilibria   than   surface  water


because of   the oxygen-poor environment.  Nlchol  et al.  (1967)  suggested that


1n  add,  water-logged  soils,  manganese  passes  freely Into  solution  and


circulates   In  the  groundwater.   On  entering  stream waters  with  average pH


and  biological  oxidation  potential (Eh)»  manganese  1s  precipitated,  thus


giving rise to  stream  sediments enriched with manganese.   Mitchell  (1971)


also showed that the mobilization of manganese  was greatly  enhanced  1n add,


poorly drained podzollc soils and groundwaters.   Josephson  (1980)  found that


manganese  exists   1n  a  reduced  state  1n  groundwater   and  that  1t  can  be


readily  leached  from  waste  sites  or from natural  sources.  High levels of


divalent  manganese may  also be  found  1n  add  mine  drainage  (see  Section


3.6.2.).


    Various  opinions  exist   regarding  the  dominant  form  of  manganese  1n


seawater.   According  to Slllen  (1961),  the  dominant  form  of manganese 1s


Mn(OH)   or   Mn(OH) .    Moklevskaya   (1961)  and   Spencer  and  Brewer  (1971)
      O            T"

found that   1n water of the Black  Sea,  the  dominant form of  manganese was  the


divalent  form.   Fukal  and  Huynh-Ngoc  (1968) found  that divalent manganese


remained  1n  that  form 1n seawater  for a long period of  time.   According to







1797A                               3-55                              4/30/83

-------
Breck  (1974),   the  main  species  are  MnO?  and/or  Mn304-   Ahrland  (1975)
considered  that  dispersed  Mn02(s)   1s  predominant.   Musan1-Marazov1c  and
                             54
Pucar (1977) concluded  that    Mn  Introduced  1n  divalent form  Into  seawater
behaves  as a cation.
    3.5.3.2.   MICROBIAL TRANSFORMATION -- Bacteria  are  Important agents  1n
determining  the  form  and  distribution  of  metals   1n   the  environment.
Alexander  (1967)  described how the  availability of  manganese  1n  soil  or
water 1s  affected by  microorganisms.   Several processes can  occur:   release
of  Inorganic  manganese  Ions   during  decomposition  of  organic  material;
Immobilization  of  Ions  by  Incorporation Into mlcroblal  tissue;  oxidation of
manganese to a  less available  form;  direct,  enzymatic reduction  of  oxidized
manganese; or Indirect  transformation  (especially reduction)  through changes
1n pH or  E .   Saxena and Howard  (1977) also concluded  that  bacteria  play a
major  part  1n  the  modification,  activation and  detoxification  of  heavy
metals.
    For  example,  manganese  usually enters a  lake 1n the  Insoluble  oxidized
form, which  settles  to the  sediment.  Manganese-reducing  bacteria may  be
active 1n  the  sediments,  or manganese  may be  reduced  by the  lowering  of pH
resulting  from  general  mlcroblal  activity  (I.e.,  0   consumption  or  the
production  of  addle  metabolites)  (Kuznetsov,   1970;  Alexander,  1977).   In
the first case  the reduction 1s enzymatic; 1n  the second 1t 1s nonenzymatlc.
Reduced  manganese then  diffuses  upward 1n  the   sediment  or  Into the  water
column.    In Lake  Pannus-Yarvl  of the  Karelian  Isthmus   (USSR),  Iron- and
manganese-reducing bacteria  are present 1n the upper 10  cm  of the sediments.
Reduced  manganese 1n  the  bottom  waters  of  the  profundal  zone  reaches  1.4
mg/8., whereas  the total manganese concentration  1n  the  rest of  the  lake 1s
only 0.01  mg/a,  (Kuznetsov,  1970).
1797A                               3-56                             4/30/83

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    Manganese-oxidizing bacteria  can be divided  Into  two functional groups.
The first  are  Included among the  "Iron  bacteria,"  or  "that group of aerobic
bacteria which  appear  to utilize  the  oxidation of  ferrous  and/or manganous
Ions  as  an  essential  component  1n  their  metabolic  functioning" (CulUmore
and McCann,  1977).   These have  been  assumed  to be chemoautotrophs, utilizing
energy  from the  reduction   of  manganese  to  carry  out  synthetic processes
(Kuznetsov,  1970),  but others  have questioned this  conclusion   (Alexander,
1977;  Konetzka,  1977).  The  second  group  consists  of  heterotrophs  possess-
ing  a slime  capsule  that  can  absorb  divalent  manganese.   Oxidation  then
occurs  within   the   sheath,  which  becomes  Impregnated  with  the hydroxide
(Kuznetsov, 1970).
    Divalent  manganese entering  the  water  column  from  the sediments  1s
precipitated by  these organisms,  usually  1n  the  form of  hydroxides.   This
leads  to  a repetition  of  the  redox  cycle.   However,  1n  lakes  such  as
Pannus-Yarvl where  bottom currents  carry  the  reduced  manganese   out  of  the
profundal  zone and  Into  more shallow and  highly  oxygenated areas, microblal
oxidation  1n the  sediments  can  lead to  the  formation  of  manganese lake ores
(Kuznetsov, 1970).
    Bacterial oxidation  of  Mn *  has also  been  Implicated 1n  the formation
of manganese nodules on the  ocean  floor  (Silver and Jasper, 1977).  However,
this  conclusion   1s  far  from certain,  as  some nodule-associated  bacteria
catalyze manganese  accretion via  oxidation  while  others  catalyze manganese
reduction  (Ehrllch,  1972).
    Iron  bacteria can  be  a tremendous  nuisance  In   water   supply  systems
because  of their  tendency  to foul  pipes  and  other  surfaces  with  Iron  or
manganese oxides.   This problem  Is especially  acute 1n wells  1n many regions
of the world.   Most  study of conditions contributing  to  these problems  has
focused  on  Iron  rather than  manganese,  and the  role  of  the  latter  remains

1797A                               3-57                              4/30/83

-------
poorly  understood  (Culllmore and  McCann,  1977).   Luthy (1964)  stated  that
0.05  mg Mn Vft  1s  undesirable  because  of discoloration  of  the water,  and
that  measures  for  bacterial  control  should  be  taken  at  levels  >0.15  mg
Mn  /ft.    Control   measures  Include   sterilization   of   equipment   before
drilling of wells, and treatment of affected  systems  by  chlorlnatlon,  acidi-
fication, or other antibacterial agents (CulUmore and McCann, 1977).
    In  the  soil, microorganisms play  an  Important  role 1n  determining  the
availability of  manganese  to plants.   Several  genera of bacteria  and  fungi
are  capable of  oxidizing  soil manganese,  many  even  under  slightly  add
conditions.  Numerically, the manganese  oxldlzers  may constitute  up to 5-15%
of  the  total  viable  mlcroflora.  Addition  of organic  matter  to  soils  can
Increase  manganese  oxidation  by  stimulating  population  Increase  of  these
groups  (T1mon1n  and  Giles,  1952).   Since  the  oxides are  less available  or
unavailable  to   plants,   symptoms  of  manganese   deficiency   may   result
(Alexander, 1977).
    Regeneration  of  reduced manganese may be  enzymatic  or nonenzymatlc,  as
1n water.   The reduction  proceeds  more rapidly 1n  poorly  drained soils.   In
such cases, manganese phytotoxldty may also  occur (Alexander, 1977).
    3.5.3.3.   BIOCONCENTRATION —  The    tendency   of   a   substance  to   be
concentrated 1n  organisms  will have  an  Important  effect on  Us  ultimate
distribution 1n  biological  and  nonblologlcal  ecosystem compartments.   Figure
3-2 shows an example  of  concentration  factors for  manganese  1n an  estuarlne
system  (Hudson River), determined  by  Lentsch  et  al.   (1972).  They observed
that filamentous  algae have  the greatest concentration factor, and the  most
predatory organism has the  lowest  concentration factor.   They also observed
that the higher organisms do not have higher concentration  factors, as  these
seem  to  be capable  of   regulating  manganese.    Thus,  blomagnlf1cat1on  or
Increasing accumulation with trophic  level  evidently was  not occurring.

1797A                               3-58                              4/30/83

-------
03
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-------
3.6.   ENVIRONMENTAL LEVELS AND EXPOSURE
3.6.1.   A1r.
    3.6.1.1.   NATIONWIDE TRENDS -- In  1953,  the U.S. PHS  Initiated  an air
sampling program  1n  17  cities.   Some samples were  analyzed  Individually and
others  as  quarterly  composites.    Twelve  nonurban  samples  collected  1n
1955-1956 at  Point  Woronzof,  Alaska,  showed an  average  manganese  concentra-
tion  of  0.01  ug/m3,  with  a  maximum  of  0.02 ug/m3  (U.S.  DHEW,   1958).
Over  100 suburban  samples  collected   at  nine  different   locations  1n  the
                                                 3
United  States  1n  1954-1956  averaged  0.06 ug/m ,  with  a  maximum value  of
          3
0.50  ug/m   1n  Kanawha  County,  West  Virginia.   Nearly  2000 urban  samples
                                           3
collected In  1953-1957  averaged  0.11   ug/m  ,  with  a  maximum value of  9.29
    3                                                                 3
       at   Cincinnati,   Ohio   1n  1955.   Concentrations  >3.0  ug/m   were
found  1n  Anchorage,  Alaska 1n  1954-1955,  probably after  volcanic  eruption;
1n  Philadelphia,  Pennsylvania  1n  1954;  and  1n  Chattanooga,  Tennessee  1n
1955-1956.
    The National A1r  Surveillance Network  started analysis January  1,  1957,
at  26  randomly-selected stations  24 hours/day  for  1  year.   Comparison  of
data  from  different  years  Involves  problems   because  of  changes  1n  the
analytical methodology and the number and position of  stations.   However,  an
examination  of  nationwide  summaries  of  these  data  does  permit  a  rough
assessment of national trends.
    The data for all  NASN  sites  for 1957-1969  are summarized  1n  Table  3-17.
The sites  are  categorized  Into four concentration  ranges.  Since  urban  and
nonurban data are not segregated  and the majority  of  sites fall  Into the  low
                   3
range  (<0.099  ug/m  ),  this  display serves  primarily  to show  the  number
of  urban  sites  with  particularly  high  ambient  manganese  concentrations.   A
comparison  of  1957-1963 data  with  post-1963 data shows  a clear decline  1n
                                                             3
the  percentage  of   sites  with   concentrations  >0.100  ug/m •   Table  3-18

1797A                               3-60                             5/03/83

-------
                                  TABLE 3-17

         Number of National A1r Surveillance Network Stations within
  Selected Annual Average Manganese A1r Concentration Intervals, 1957-1969*
Number and Percent of Stations
by A1r Concentration Interval, ng/m3
(percent shown 1n parentheses)
Year
1957-1963
1964
1965
1966
1967
1968
1969
1957-1969
<0.099
76
(59.4)
68
(73.1)
132
(84.1)
113
(88.3)
121
(85.2)
126
(86.9)
169
(80.9)
805
(80.4)
0.100-0.199
29
(22.7)
12
(12.9)
14
(8.9)
8
(6.3)
13
(9.2)
11
(7.6)
23
(11.0)
no
(11.0)
0.200-0.299
10
(7.8)
6
(6.5)
5
(3.2)
4
(3.1)
4
(2.8)
2
(1.4)
9
(4.3)
40
(4.0)
>0.300
13
(10.2)
7
(7.5)
6
(3.8)
3
(2-3)
4
(2.8)
6
(4.1)
8
(3.8)
47
(4.7)
Total
128
(100)
93
(100)
157
(100)
128
(100)
142
(100)
145
(100)
209
(100)
1002
(100)
*Source:  NASN, 1957-1969
1797A
3-61
5/03/83

-------
                                 TABLE 3-18

              National A1r Surveillance Network  Stations with
                Annual Average Manganese A1r  Concentrations
                          Greater Than 0.5
Year
1958
1959
1960
1961
1963
1964
1965
1966
1967
1968
1969
Station
Charleston, WV
Johnstown, PA
Canton, OH
Gary, IN
Canton, OH
Philadelphia, PA
Johnstown, PA
Philadelphia, PA
Charleston, WV
Johnstown, PA
Philadelphia, PA
Lynchburg, VA
Charleston, WV
Niagara Falls, NY
Knoxvllle, TN
Johnstown, PA
Niagara Falls, NY
Johnstown, PA
Philadelphia, PA
Manganese
Average
0.61
2.50
0.72
0.97
0.57
0.70
1.44
0.62
1.33
2.45
0.72
1.71
0.60
0.66
0.81
3.27
0.66
1.77
0.50
Concentration, i
Maximum
Quarterly
1.10
5.40
1.10
NR
NR
NR
NR
NR
NR
3.90
1.70
2.50
1.70
1.30
1.50
NR
1.30
2.10
1.30
ng/ir?
Maximum
24-hour
7.10
7.80
2.20
3.10
2.90
>10.00
6.90
3.70
>10.00
NR
NR
NR
NR
NR
NR
14.00
NR
NR
NR
*Source:   NASN,  1957-1969

NR = Not  reported
1797A
3-62
5/03/83

-------
gives  NASN  sites   for   which   average  concentrations  were  >0.5

Higher  concentrations   for  shorter  average  times  may  be  of  considerable

significance  1n  the  evaluation  of   the  potential  biological  effects  of

                                                           3
airborne  manganese.    Several   24-hour  values  >10   v-g/m    were  observed

during this time period (see Table 3-18).

    A comparison of  urban and nonurban NASN data  for  1966-1967 was provided

by McMullen  et  al.   (1970).   Urban  samples  showed an  arithmetic  mean manga-
                                   o
nese  concentration   of  0.073  ug/m ,   while  the  mean  for  nonurban  samples
                                       3
decreased  from  0.026   to 0.005  ug/m  with  Increasing remoteness  of  the

monitoring  site from  urban  areas (Table  3-19).   While this decrease  of

manganese  concentration  primarily  reflects  a  decrease  1n  total  suspended

partlculates, percent  manganese  1n TSP mass also decreased with Increasing


remoteness (McMullen et al., 1970).

    An examination of  NASN  data for the early  1970s shows  a  further  decline

1n ambient manganese levels  at  urban   sites, and  Indicates  some reduction at

nonurban sites  as well.   The  U.S.  EPA  (1977a)  reported that  the median (50th

percentlle)  value  of  annual  average   manganese  concentrations for 92  urban

                                    3                             3
sites  declined  from   0.040  ug/m   1n  1965   to  0.016  v.g/m    In  1974.

When  urban  values   for   the  period 1970-1971  were  compared   to  those  for

1973-1974, a  50% decline was observed 1n  both the  50th  and 90th percentlle

values for  manganese,  Indicating  a reduction by  about half  1n  both median

and  extreme  levels.    During  this  same Interval, the  reductions 1n TSP  at

these percentlles were only 4%  and 13%, respectively,  Indicating  that this

reduction was  not  simply related to   a  general  Improvement 1n  air  quality.

The  trend  for  manganese  was  thought   to be  attributable to controls  1n  the

metals  Industry.   Data  examined  for  16 nonurban  sites were  also  said  to

Indicate a downward  trend for manganese,  but  this  conclusion  was  described

as tenuous (U.S. EPA, 1977a).



1797A                               3-63                             5/03/83

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                                  TABLE 3-19

           Average Manganese Concentration 1n Ambient A1r  and Total
  Suspended Partlculates (TSP) 1n Urban and Nonurban NASN  Sites,  1966-1967*
          Stations	
                                       TSP              Mn             Mn/TSP
     Type             Number         (ug/m3)          (ug/m3)           (X)


Urban                  217            102              0.073            0.07
Nonurban
Proximate
Intermediate
Remote
Total nonurban

5
15
10
30

45
40
21
34.5

0.026
0.012
0.005
0.012

0.06
0.03
0.02
0.03
*Adapted from McMullen et a!.,  1970
1797A                               3-64                              4/29/83

-------
    The  frequency  distributions  of  quarterly analytical  values for manganese
at  all  urban and  nonurban  NASN  sites for  the  years 1970-1982  are  given 1n
Table  3-20 and  3-21,  respectively.   Prior  to  1977,  quarterly  values  were
based  on  single  analyses  of  filter  composites  (U.S.  EPA,  1979a).   Since
1977,  Individual  filters  were analyzed.   Therefore,  to  permit comparison of
these  data with the earlier  data,  quarterly arithmetic  means of all values
for  each  site  were  used  to simulate  quarterly  composite  values  1n  the
frequency  distributions (Barrows, 1983).  A  rigorous trend analysis  of these
data  1s  not  possible  due  to  changes 1n  sites and  methodology.  Decreases
over  the period are Indicated,  however,  both  1n  median  and extreme concen-
trations,  for both urban and rural areas.
    3.6.1.2.   AREA  STUDIES — Pollution problems  and  trends  can  also  be
characterized  on  a more  local scale.  A few area studies  1n which ambient
manganese  concentrations are given  will  be  discussed.   In 1964-1965, a study
was undertaken  of  air pollution  1n  the Kanawha  Valley,  West Virginia (NAPCA,
1970).   Average  TSP  levels   for   sites  1n  the  area  ranged from  132-413
    3                                                               3
ng/m  ,   compared   to   the  national   urban   average  of   100   v.g/m   (Table
3-22).   Yearly  average suspended  manganese  concentrations  were as  high  as
         3
8.3  ug/m  , with  quarterly composite samples  ranging  up  to  11.0  and  13.0
    3
ug/m   for  the  Smlthers  and  Montgomery  communities,  respectively.   The
major manganese source was  a ferromanganese  plant,  with  additional contribu-
tions  from a  large  coal-burning Industrial  steam-generation  plant  (NAPCA,
1970).   However,  NASN  data collected 11  years  later  (1976)  1n  two Kanawha
Valley communities  (although  not  necessarily the same sampling  sites)  Indi-
cate decreases  of  an  order of magnitude  1n ambient manganese concentration
(see lable 3-22; U.S.  EPA,  1979a).
1797A                               3-65                              5/03/83

-------
 US
                                                                              TABLE 3-20
                                    Urban NASN Sites, 1970-1982:   National Cumulative Frequency Distributions of Quarterly Values

                                                                for  Manganese Concentration (ug/ni3)3*''
 i
 er>
-p>
•x
ro
CO
CO
Percentlles
Year
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
Numberc
795
716
708
559
594
695
670
741
568
429
437
477
309
Minimum
L0«
LD
LD
LD
LD
LD
LD
0.0051
0.0043
0.0022
0.0030
0.0040
0.0031
10
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.017
0.016
0.011
0.009
0.011
0.011
30
0.03
0.04
0.02
0.02
0.02
0.02
0.02
0.025
0.025
0.017
0.015
0.017
0.017
50
0.04
0.05
0.03
0.02
0.02
0.03
0.03
0.032
0.034
0.025
0.021
0.024
0.023
70
0.06
0.07
0.04
0.04
0.04
0.04
0.04
0.045
0.043
0.035
0.031
0.033
0.032
90
0.15
0.16
0.09
0.07
0.07
0.07
0.08
0.077
0.088
0.073
0.063
0.059
0.063
95
0.23
0.24
0.12
0.11
0.11
0.10
0.12
0.100
o.ni
0.102
0.093
0.084
0.081
99
0.49
0.46
0.22
0.29
0.21
0.18
0.27
0.297
0.185
0.158
0.133
0.138
0.170
Maximum
2.10
1.95
0.86
0.56
0.35
0.72
0.74
0.632
0.300
0.448
0.141
0.303
0.661
Arithmetic
Mean
0.07
0.08
0.04
0.04
0.04
0.04
0.04
0.045
0.043
0.035
0.030
0.032
0.033
Standard
Deviation
0.12
0.11
0.06
0.05
0.04
0.04
0.05
0.051
0.035
0.039
0.026
0.030
0.047
Geometric
Mean
0.04
0.05
0.03
0.02
0.02
0.02
0.03
0.034
0.034
0.026
0.022
0.025
0.024
Standard
Deviation
3.13
2.81
2.76
2.72
2.39
2.49
2.60
2.486
2.043
2.443
2.111
2.214
2.846
           aSource of 1970-1976 data: U.S. EPA, 1979a


           bSource of 1977-1982 data: Barrows, 1983


           cNumber of quarterly site values.  From 1-4 quarterly  values  were available per site.


           dL1m1ts of  discrimination  (LO)  for  1970-1976 were  =0.0025 ug/m3,  but  varied among  years.  LD  for  1977-1982  ranged  from 0.00042-0.0024
            vg/m3.

-------
                                                                            TABLE 3-21
us
— J
3»
Nonurban NASN Sites,
1970-1982: National Cumulative Frequency Distributions
for Manganese Concentration (vg/m3)a»b
PercentHes
Year
1970
1971
1972
1973
1974
^ 1975
S 1976
1977
1978
1979
1980
1981
1982
Number0
124
97
137
100
79
98
98
126
65
44
35
43
33
Minimum
LD<1
LD
LD
LD
LD
LD
LD
LO
0.0011
LD
LD
LD
LD
10
0.003
0.003
LD
LD
LD
LD
LO
0.003
0.003
0.002
LD
0.003
0.001
30
0.006
0.009
LD
LD
0.001
0.004
0.005
0.005
0.006
0.004
0.004
0.004
0.003
50
0.012
0.013
0.003
0.002
0.004
0.006
0.007
0.009
0.008
0.005
0.005
0.006
0.005
70
0.018
0.022
0.007
0.004
0.007
0.009
0.010
0.012
0.010
0.007
0.007
0.009
0.007
90
0.035
0.032
0.016
0.011
0.017
0.014
0.025
0.021
0.015
0.011
0.014
0.015
0.009
95
0.041
0.041
0.029
0.022
0.023
0.018
0.030
0.030
0.018
0.015
0.018
0.021
0.009
99
0.066
0.064
0.039
0.030
0.027
0.031
0.036
0.049
0.030
0.024
0.019
0.025
0.015
Maximum
0.068
0.102
0.046
0.030
0.033
0.040
0.046
0.122
0.036
0.024
0.019
0.025
0.015
of Quarterly Values
Arithmetic
Mean
0.015
0.018
0.007
0.004
0.006
0.007
0.010
0.012
0.009
0.006
0.007
0.008
0.005
Standard
Deviation
0.013
0.015
0.009
0.005
0.007
0.007
0.009
0.013
0.006
0.006
0.005
0.006
0.003
Geometric
Mean
0.012
0.013
0.003
0.002
0.004
0.015
0.010
0.008
0.007
0.005
0.005
0.007
0.004
Standard
Deviation
2.11
2.09
2.81
2.79
2.52
2.19
2.21
2.468
1.810
1.862
1.970
1.897
1.807
o
CO
oo
os
aSource of 1970-1976 data: U.S.  EPA, 1979a
••Source of 1977-1982 data: Barrows, 1983
cNumber of quarterly site values.   From 1-4 quarterly values  were available per  site.
dL1m1ts  of  discrimination  (LO)  for  1970-1976 were  =0.0025 ug/m3,  but  varied among  years.   LO  for  1977-1982  ranged from  0.00042-0.0024
 vg/m3.
NR = Not reported

-------
                                                                                TABLE  3-22

                                                   Manganese  Concentrations  1n  A1r,  Kanawha  Valley Area,  West Virginia*
 I
 C^
 C»
Sampling Site
and Site Number
Falls View (1)
SmUhers (5)
Montgomery (6)
Cedar Grove (7)
Mar met (11)
Kanawha City (13)
Charleston (15)
West Charleston (17)
North Charleston,
West (19)
South Charleston,
East (20)
Ounbar (22)
St. Albans (24)
NHro (25)
NHro, West (27)
TSP
(WJ/m3)
Study Period
Average
179
347
413
235
242
287
189
209
241
298
199
223
179
132

Fall Winter
1964 1964-1965
3.40
11.00 6.50
13.00
4.20 3.50
3.60
3.30 1.10
0.91
0.96
0.52
2.00 0.26
0.24
0.43 0.44
0.59 0.28
0.08
Suspended Manganese (ug/m3) Settled Manganese
Quarterly Composites (nq/cm2/month)
Spring Summer Study Period Yearly Averageb Study Period
1965 1965 Average 1976 Average

4.50 3.00 8.30 19,300
2,700
1.80 0.32 2.45 130
110
0.53 0.27 1.30 80
0.07

240
0.23 0.17 0.67 0.04 320

0.06 0.06 0.25 80
0.10 0.09 0.27 90

            aSource:  NAPCA, 1970


            bSource:  U.S. EPA,  1979a.  NASN  data, not necessarily same sampling locations.
oo
CO

-------
    A nearby region along  the  Ohio  River  between Marietta, Ohio and Parkers-


burg,  West  Virginia  was  studied  during  the period  1965-1966  (U.S.  DHEW,


1967).  A1r  quality  1n  this area  was Influenced by a  large plant producing


manganese metals and alloys.   Sampling of  ambient participate using a direc-


tional  sampler  or during  different  wind  directions  showed that  for  sites


both  north  (Marietta)  and  south of the plant (Vienna,  Parkersburg),  ambient


manganese  concentration  was always  substantially  higher  when  the wind  was


blowing from the direction  of  the  plant  (Table 3-23).   The  trend for TSP was

                                                                            3
not  nearly  so  clear,  however.   Manganese   levels  as  high  as 11.4  ug/m


were  observed  1n  24-hour  samples  downwind   of  the plant.   At one  site,  a


composite of  samples  collected by  a  directional sampler  selective  for  wind

                                                                    o
direction  showed  manganese  levels  10   times   higher   for   the 90   sector

                                o

toward  the   plant  (4.1   v.q/m )   than   for  the  remaining   270°   sector

         3
(0.4 ug/m ).   Recent  unpublished  monitoring data  for  two  of  these  sites


have  been  provided by  the current operator  of   the manganese  plant  (Moore,


1983a,b).    The  mean and range  of  at least  14  24-hour  samples  during  the


winter  (December 2-February 4)  of  1982-1983  Indicate  substantial  reductions


(by roughly an order of  magnitude)  1n manganese  when compared with data from


the earlier  study  (see Table  3-23).  TSP  levels were also  reduced.   Manga-


nese  production  rates  at this  plant  during   the  recent  sampling period  were


reported to be 60-70% of those  for  1965-1966   (Moore, 1983b).


    Ambient manganese  levels  1n New  York  City are  substantially  lower  than


those  1n  areas  Influenced  by   the  manganese metal  and  alloy  manufacturing


Industry.   However, trends  can be noted  here as well.  Data  of Klelnman  et


al. (1980) for NYU Medical  Center  and a location 1n the Bronx show substan-


tial  reductions  1n  annual   averages  for  manganese  and  several  other  metals


during the years 1968-1975  (Table 3-24).    The greatest decrease was  observed
1797A                               3-69                              5/03/83

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 1C
 •—I
                                                            TABLE  3-23

Ambient A1r Sampling Data for Total  Suspended  Participates  and Manganese (1n
                                                    1965-19663 and 1982-1983°
                                                                                                      1n the Marietta.  OH-Parkersburg, WV  Vicinity,
Site
Vienna
Outc
Marietta (Central)
Marietta (West)
Parkersburg (Central)
Nov.
TSP

257d
309d
1876
3. 1965*
Mn

1.6d
11. 4d
0.29e
Nov. 27.
TSP

121d
204d
8ie
1965a
Mn

1.6d
6.6d
0.0C
Jan. 15.
TSP
196d
54d
67^

124d
19663
Mn
3.4d
O.ld
O.le

0.7d
Jan. 25.
TSP
278d
128d
155e

219d
19663
Mn
2.0d
0.2d
O.le

0.7d
Composite,
Jan. 11-31. 1966a
TSP Hn
197 4.1
63 0.4
132 0.6

134 0.7
Mean (Range),
Dec. 1982-Feb. 1983b
TSP Hn
47 (12-97) 0.14 (0.03-0.56)

32 (20-48) 0.13 (0.03-0.51)

   aSource: U.S. DHEW. 1967


   °Source: Unpublished data of El kern Metals Co., Marietta,  OH  (Moore,  1983b)


   C01rect1onal sampler;  "In":  90° sector toward ferromanganese plant;  "Out":  remaining 270° sector


   dS1te was downwind of  ferromanganese plant during sampling period


   eS1te was upwind of ferromanganese plant during sampling  period
00

-------
                                  TABLE 3-24

              Concentrations of Trace Metals 1n A1r Measured at
                  Three Locations In New York City* (ng/m3)
Element
Cd
Cr
Cu
Fe
K
Mn
Na
N1
Pb
V
Zn
TSP (ng/m )
Element
Cd
Cr
Cu
Fe
K
Mn
Na
N1
Pb
V
Zn

1969
10.0
33.0
526
NR
NR
89.0
NR
1390
2110
874
670
134

1968
14.0
49.0
133
NR
NR
54.0
NR
150
3820
1230
730
New York Un1
1972
6.0
11.9
63.0
1490
240
27.5
1130
30.7
1370
68.9
380
82
Bronx
1969
9.0
23.0
115
NR
NR
40.0
NR
122
2760
795
1120
verslty Medical
1973
7.1
8.9
55.7
1580
358
28.1
1990
45.0
1240
86.0
311
80
, New York
1972
4.0
7.0
60.0
1940
NR
29.0
NR
210
2000
53.0
304
Center
1974
6.0
10.8
46.8
1410
371
23.1
604
45.4
1400
72.6
338
71














1975
4.2
8.5
43.9
1010
99.1
19.8
800
35.2
1070
38.8
294
52

1973
3.5
5.3
52.5
1440
NR
30.2
NR
311
1580
80.0
289
*Source:   Klelnman et al.,  1980

NR = Not  reported

1797A
3-71
5/03/83

-------
over the years 1968-1972.   TSP  levels measured at  the  Medical  Center  showed
that the decrease was concomitant with a decrease 1n TSP.
    3.6.1.3.   PARTICLE  SIZE — Techniques  for  accurately   characterizing
particle-size distributions  for  trace  metals  1n ambient  partlculate  matter
have been available  and  Improving  since about 1970.  Lee  et  al.  (1972)  used
cascade Impactors to achieve a size fractlonatlon of  ambient  aerosols  1n six
United  States  cities  during 1970.   Their data  showed that,  on an  annual
average, 45-62%  of   ambient  manganese  was  1n particles  of <2 vim  diameter.
Bernstein and Rahn (1979) used a size-selective  cyclone sampler  to  fraction-
ate New York CHy urban  aerosol  during 2 weeks  of  sampling 1n  August,  1976.
In  these  samples,  64-68%  of manganese  was found  1n  particles  of  <2.5  vim
diameter.    Manganese  was   blmodally  distributed,  with  a  peak   1n   the
0.5-1.5 v-m  fraction,  a  nadir  1n   the  1.5-2.5  vim  fraction,  and  a  second
peak  1n the  2.5-3.5  y.m  fraction.   A  single  week  of  sampling with  this
device  1n   November,  1974,  had  shown  only  the latter   (2.5-3.5  >im)  peak
(Bernstein  et al.,  1976).
    More recent data  tend  to Indicate that less of  the ambient  manganese 1s
found  1n  fine  particles.   Dlchotomous  samplers, which segregate  particles
Into  fine  and coarse fractions,  have  been  used  widely  since  about  1975.
Davis  et  al.  (unpublished  manuscript)  performed  analyses  of  104  selected
filter pairs from dlchotomous samples collected  1n  22 geographically  diverse
cities  1n  the  United  States during  1980.   The  size  classes  were  <2.5  vm
(fine)  and  2.5-15  >im   (coarse).   Filters  with   a   high  level  of   total
partlculate were selected to facilitate analysis.   Therefore,  the sample has
some bias,  and the concentrations are not  representative.   However,  this was
considered  an excellent  data base for  examining relative amounts of  manga-
nese 1n fine and  coarse aerosol.
1797A                               3-72                             5/03/83

-------
    Table 3-25 shows that the manganese  concentration  (1n mg/g) 1n particles
of  each  fraction  1s highly  variable,  but tends  to  be higher  1n  the coarse
particles.  Since coarse particle mass also  tends to be greater, the overall
precentage  of  manganese found  1n  fine  particles tends  to  be <50%  of  the
total measured; the average for this study was 28%.
    The  total  partlculate  measured  by  the  dlchotomous  sampler (DS)  with  a
15 urn  size-selective  Inlet  1s  less than  the TSP  measured  by high-volume
samplers.   The  ratio DSrTSP has  been  measured for  samples  where  TSP 1s >55
     3
ug/m  (Pace  and  Frank,  1983).    Ninety  percent  of all   values   for  the
ratio were  between  0.36 and 0.76;  the mean  was 0.56.   The ratio 1s  somewhat
higher when TSP  1s  lower.   If manganese  1s  assumed  to be distributed fairly
evenly over particle mass  for particles  of  different  sizes, then  this ratio
can  be  used   to   compare   dlchotomous-sampler  manganese with  high-volume-
sampler manganese.   The  percentage  of manganese present 1n the fine  fraction
would  then  have  an  average  of  28% x 56%,  or  16%,  of  the  total  measured.
However,   since the  manganese concentration (1n   mg/g)   1n  coarse  particles
tends to be higher than 1n fine particles, this average 1s probably too high.
    This  Indicates that  only a small percentage of the manganese measured by
the  high-volume  sampler usually  1s  present  In the  fine  fraction.   However,
It  should be  noted  that of  the  22  cities  examined  1n this  study,  the dty
                                                                      3
(Akron,  OH) with  the  highest  manganese  concentration  (0.129 y.g/m )  also
had  the  highest percentage  1n the  fine  fraction  (66%).   Therefore,  1n high-
exposure  situations  the relative amount  1n  the  fine  fraction  may  be large.
If  the DS:TSP  ratio was also high  (e.g., 0.76),  the  percentage could  be as
high as 66% x  76%, or 50%.
1797A                               3-73                             5/03/83

-------
                                  TABLE 3-25
       Selected Olchotomous Sampler Data on Manganese and Particle Mass
                         from 22 U.S. Cities 1n 1980a
                                       Manganese
aSource: Davis et al., unpublished manuscript
''Particle size:  fine, <2.5 um; coarse, 2.5-15
GAr1thmet1c mean by city
                         Particle Mass
Parameter1*
A1r concentration (ng/m^)
Fine
Coarse
Total
Particle concentration (mg/g)
Fine
Coarse
Percent mass 1n fine fraction
Meant
0.016
0.030
0.046
0.50
0.70
28
Range
0.001-0.085
0.003-0.078
0.006-0.129
0.029-2.36
0.27-1.75
3-66
Meanc
28.7
44.6
73.3
—
41
Range
9.7-57.1
8.2-105.6
36.0-140.4
::
15-78
1797A
3-74
4/29/83

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3.6.2.   Water.   Natural   concentrations   of  manganese  1n   seawater   are
reported  to  vary  from 0.4-10  v-Q/i   (U.S.  EPA,  1975).   Kopp  and  Kroner
(1969)  studied  trace  metals  1n  United  States  freshwaters  and  generalized
that  "1n  most  natural  waters,  the  concentration  of  manganese  1s  <20
iig/ft".     In   surface   freshwaters,   background   levels    are   frequently
exceeded due  to  human  activities.   Manganese concentration ranges 1n various
United  States   lakes   and  rivers,  some  heavily  polluted,  are  given  1n
Table 3-26.
    Kopp and  Kroner  (1969)  summarized  trace-element  data for 1577 water sam-
ples  collected over  the contiguous United States  and  Alaska from 1962-1967,
under the  water  quality surveillance program of  the  Federal Water Pollution
Control Administration  (FWPCA).   Dissolved manganese was  detected 1n 810 of
1577  samples;  the mean  concentrations  of  dissolved manganese for  16 drainage
basins are shown 1n Table 3-27.
    Manganese  oxides  are   common  constituents  of  suspended  materials  and
frequently  comprise  >0.1%  (>1000  iig/g)  of  riverine sediments  (Hem,  1970).
A comparison  of  suspended  and dissolved manganese 1n  Table  3-28 shows that,
1n  river  systems,  the  amount 1n  suspension  normally exceeds  the amount 1n
solution.    Exceptions   to   this  pattern  are  the  Allegheny   and  Monongahela
Rivers,  which are  characterized  by  add mine  drainage  {Kopp  and  Kroner,
1969).
    Manganese  levels  1n  groundwaters  frequently are  much  higher   than  1n
surface waters because  the more add  and reducing conditions  which  prevail
In  the  sub-surface  environment  promote  dissolution of  manganese  oxides.
Manganese   concentrations   as   high   as   9600   v-g/fi-  1n  add  groundwater
(pH=4.0)   and  1300   v.g/8.   1n  neutral   groundwater   (pH=7.0)   have   been
reported  (Hem, 1970).


1797A                               3-75                             5/03/83

-------
                                  TABLE 3-26

                  Concentration of Manganese 1n Various Lake
                               and River Waters
        Locality
Concentration
Range (v.q/9.)
      Reference
Wisconsin Lakes

Mississippi River

Llnsley Pond, Connecticut

Maine Lakes

Yukon River, Alaska

Mississippi River

Southeastern Missouri
  Streams
  3-25

  80-120

  50-250

  0.02-87.5

  181

  12-185

  10-2420
Juday et al., 1938

W1ebe, 1930

Hutchlnson, 1957

Klelnkopf, 1960

Durum and Haffty, 1963

Durum and Haffty, 1963

Gale et al., 1973
1797A
   3-76
              4/29/83

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                                  TABLE  3-27
         Mean  Concentrations of  Dissolved Manganese  by  Drainage  Basin*


                     Drainage  Basin                      ug Mn/ft

               Northeast                                    3.5
               North  Atlantic                               2.7
               Southeast                                    2.8
               Tennessee River                              3.7
               Ohio River                                 232.0
               Lake Erie                                  138.0
               Upper  Mississippi                            9.8
               Western Great Lakes                          2.3
               Missouri River                              13.8
               Southwest-lower Mississippi                  9.0
               Colorado River                              12.0
              Western Gulf                                10.0
               Pacific Northwest                            2.8
              California                                   2.8
              Great  Basin                                  7.8
              Alaska                                      18.0

*Source:  Adapted from Kopp and Kroner, 1969
1797A                               3-77                             4/29/83

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co
I
                                                          TABLE  3-28


                                   Dissolved and Suspended  Manganese 1n Five U.S. Rivers*
Location
Delaware River
At Martins Creek, PA
At Trenton, NJ
At Philadelphia, PA
Allegheny River
At Pittsburgh, PA
Monongahela River
At Pittsburgh, PA
Ohio River
Below Addlson, OH
Kanawha River
At W1nf1eld Dam, WV

Detection
Frequency
(X)
40
27
31
60
93
51
87
Dissolved
Mean of
Positive Values
(ug/D
2.9
3.2
4.2
>1000
607
57
44

Detection
Frequency
(X)
93
100
100
100
87
100
100
Suspended
Mean of
Positive Values

OS
CO

-------
    In  a  1962 U.S. Geological  Survey study of public  water  supplies  of the
100  largest  dtles 1n  the  United States, Durfor  and  Becker  (1964) reported
manganese  concentrations  of  up to 2500  iig/ft  for  treated water.   Of these
water   supplies,  97%   contained  concentrations  below  100  vuj/8.-    A  U.S.
Public  Health Service  (U.S.  PHS)  community water  survey 1n  1969 examined
2595  samples  of  tap  water  from  969 community  water  supplies  (U.S. DHEW,
1970).   The  maximum  concentration of  manganese  was   1320  ug/S.,  but 91.9%
of samples and 91% of  supplies  did not exceed 50 ug/i-
    As  part  of  the  first  Health and  Nutrition  Examination  Study (HANES  I
Augmentation  Survey  of  Adults),  conducted  1n  1974-1975, tap  water  samples
from  public  and  private  water  supplies  of  35  urban  and  rural,  randomly
chosen  sampling  areas  were  analyzed for  trace  metals  (U.S.  DHEW,  1978).
Unpublished  data  for  manganese (Table  3-29) Indicate  that  higher manganese
concentrations  can  be  found  1n private  wells  than  1n  public water supplies
(Greathouse,  1983).   Manganese  concentration at  the  95th percentlle was   3
times   higher  1n   private   (228  U9/&)   than   1n   public   supplies   (78
ug/fc).   The  median  level for  private  supplies  was below  detection  limits
while  that for  public supplies  was  4  ug/&;  however,  since  the detection
limit was  calcium dependent   (U.S.  EPA,  1978b)  and may have  been higher for
private waters, the median levels may not be comparable to one another.
3.6.3.   Food.  Manganese  concentrations  were  measured  1n  foods  from  the
United  States  (Schroeder  et  al.,  1966;  Baetz and  Kenner,  1975;  Wong et al.,
1978), Great  Britain (Wenlock et  al., 1979)  and New Zealand (Guthrle,  1975).
Concentrations varied widely among food  groups, within  food  groups, and even
for a given  food  type.   Concentrations  1n various  grains  and cereals  In the
United  States ranged  from  1.17-30.76  y.g/g.   Manganese  concentrations  for
unpolished rice were  given  as  2.08  (United  States), 32.5  (New  Zealand)  and


1797A                               3-79                              5/03/83

-------
                                  TABLE 3-29

         Cumulative Frequency Distribution of Manganese Concentration
     1n Tap Waters Sampled 1n the HANES I Augmentation Survey of Adults*

Supply Type
Public
Private

Number
2853
596

25
NO
NO

50
4
NO
Percentl
75
13
34
les (ug/S
90
36
121
,,
95
78
228

99
295
977
*Source: Unpublished EPA data (Greathouse, 1983)

NO = Less than detection limits (see text)
1797A                               3-80                             4/29/83

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40   ug/g  (Great   Britain).    Most  non-cheese   dairy   products  contained
<1 v-g/g,  but  cheeses varied widely.   Swiss cheese  1n the  United States was
reported  to  contain 1.32  and  17.2  vig/g,  respectively,  by  two  different
authors.   Most  meat,   poultry  and  fish  contained  manganese  at  <2  yxj/g.
Most  fresh  fruits  contained  <2 uQ/g.  but  bananas  and  canned fruits ranged
from  this  level  to  19  and  10  v.g/g, respectively.   The  manganese content of
various  vegetables  ranged   from  0.14-12  ug/g.   Most  nuts  contained  from
7-35  ng/g,   and  certain  spices   (cloves,  ginger,  sage)   contained  >200
ug/g.   Thus,   1t  1s obvious  that  wide  differences  1n  manganese  Intake can
exist for people with differing or even with similar food habits.
3.6.4.   Human Exposure.   Data on  manganese levels  1n  air,  water  and  food
can  be  used  to  estimate human exposure  to manganese.  No  attempt  has  been
made  1n this  document  to  project  numbers  of  Individuals  subject  to given
exposure  levels.   Rather, manganese  Intakes characteristic  of  an  "average"
and a "high"  level  of exposure  are  estimated.   These estimates are presented
solely  as  a   rough basis  for  comparison   with  the  Information on  health
effects 1n the following chapters.
    3.6.4.1.   INHALATION — The degree of  Intake or absorption associated
with  human   Inhalation   exposure  to  an  aerosol   Is  highly   dependent  upon
particle  size.   Particles  of  diameter  >100 um can be  Inhaled, but  few  of
those  larger  than  =15  >im  are  likely  to  reach   the  thoracic  region  (U.S.
EPA,  1982b).   Insoluble particles  deposited 1n the  extrathoraclc region are
usually cleared  to  the  esophagus within minutes,  offering little opportunity
for  absorption   of  toxic constituents   by   the  respiratory  tract  (although
absorption  by  the  digestive   tract  1s  possible;  see  Section  3.6.4.2.).
Particles of   smaller   diameter  may  be  deposited  1n   the   thoracic  (I.e.,
tracheobronchlal  and alveolar)  regions,  to  a  degree  which  1s  dependent  on


1797A                               3-81                             5/03/83

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type of  breathing  (I.e.,  oral or  nasal),  breathing flow rate,  and  particle
characteristics.    Insoluble  particles  deposited  1n   the   tracheobronchlal
region normally  are cleared  within hours,  whereas those  deposited 1n  the
alveolar   region  would  be  expected  to remain  for  weeks,  months or  longer
(U.S. EPA, 1982b).
    Particles  of   =10  vim   are   almost  all   deposited   extrathoradcally
during nasal  breathing.   During  mouth breathing  =35% are  deposited trache-
obronchlally,  but  still practically  none  reach the  alveoli.    As  particle
size decreases,  the fractions reaching  the thoracic  region  and passing  to
the  alveoli  Increase.   Alveolar  deposition   1s  greatest   (=25-65%)   for
particles  1n  the   range  of  2-4  vim.   Nearly  all  particles  smaller  than
2 |im  reach  the  alveoli,   but  many  (=50-80%)  remain  suspended  and  are
exhaled  (U.S.  EPA,  1982).   However,  some conventions conservatively  assume
that  none  1s exhaled;  thus,  >80%  of  particles  smaller  than  2 urn  are
considered  to be  deposited  1n   the  alveoli,  and  for  particles =4-10 urn,
<30% are  alveolar and  >50%  are deposited 1n  the  tracheobronchlal region (Ad
Hoc  Working  Group  of  Technical  Committee  !46-A1r  Quality,  International
Standards Organization, 1981).
    Data  collected  by  dlchotomous  sampler  are  roughly amenable  to  exposure
estimates.   The extrathoradc fraction 1s approximately  excluded by  an upper
size  cut-off,  usually  =05 vun.   Thus,  all  aerosol  sampled  1s assumed  to
reach the  thoracic  region.   The  coarse aerosol  from the  dlchotomous sampler
1s generally  taken  to  represent  the tracheobronchlal  fraction,  and  the fine
aerosol  to  be the  alveolar  fraction  (Dzubay  and   Stevens,  1975).   This
assumption  1s a  reasonable  approximation  1f  all particles  reaching  the
alveoli  are  assumed to be  deposited,  as  mentioned above.   In  actuality, as
also  has been discussed,  the mode of  the  alveolar  deposition  curve  1s at


1797A                               3-82                             5/09/83

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2-4 vro,  and Is  usually divided  by  the  size  cut between  fine and  coarse


fractions.  However, for the purposes of  this  document,  the  conservative and


simplifying assumptions will be made  that  the  fine fraction  1s 100% deposit-


ed In the alveoli,  and  the  coarse  fraction  1s  100% deposited 1n the tracheo-


bronchlal region.


    The  NASN  monitoring  data  were  collected  using  high-volume  samplers,


which  sample  50%  of  particles of  30 v-m and  some particles  of  up  to 100


Vim  (Pace  and  Frank,   1983).    Dlchotomous   sampler   data   from  around  the


country  Indicate  that  of  the manganese  sampled  (particles  0-15  um),  an


average   of  -28%  and  a  maximum   of   ~66%  1s  1n   the   fine   (<2.5 \m)


fraction  (Davis  et al., unpublished manuscript;  see Section 3.6.1.3.)-   The

dlchotomous  sampler  collects  an average  of -56% and  a  maximum of  ~76% of


the  TSP  collected  by   the  high-volume sampler  (Pace  and  Frank,   1983;  see


Section  3.6.1.3.).  Assuming similar  percentages  for manganese, and assuming

                         3
dally  Inhalation of 20 m   of  air,  human  Inhalation  exposure  to  manganese


can be estimated from NASN data as  follows:

                                                                   3
         Alveolar deposition (ug/day) = Ambient concentration  (v.q/m  )


                        X Flne/DS X DS/TSP X 20 m3/day

                                                                       3
      Total thoracic deposition (ug/day) = Ambient concentration (vig/m )


                             X  DS/TSP X 20 m3/day


where Flne/DS  = Fine-fraction  manganese/total  dlchotomous-sampler  manganese


and  DS/TSP  =   Dlchotomous-sampler  part1culate/h1gh-volume-sampler  partlcu-


late.   Both alveolar and  total  thoracic  deposition are  estimated  since  both


could have  some role  1n causing adverse  effects.  Both  average and maximum


values for  ambient  concentration,  Flne/DS,  and DS/TSP  are used for  estimat-


ing average and maximum exposures.
1797A                               3-83                             5/03/83

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    The most recent  (1982)  ambient  air monitoring data  for  the  urban United

                                                                   o
States  show a  median  quarterly  manganese  level  of   0.023  ug/m ,  and  a

                                      3
high  quarterly  value  of  0.661  y.g/m   (see  Table   3-20).   Ambient  levels

                   3
reaching  ~10  y.g/m   were  observed  near   sites  of  manganese  alloy  manu-


facture during  the  1960s  (U.S.  DHEW.  1967;  NAPCA,  1970).   These  levels  are


of  Interest because  they  are  relatively  recent and  could  have had  some


bearing on  health studies  conducted  during  or  subsequent  to  that  period.


However, such levels  evidently are no longer occurring 1n ambient air.


    Exposure estimates derived  from these  data are presented  1n Table 3-30.


Alveolar deposition  of  manganese at current  ambient  levels 1s  estimated  as


0.072  iig/day (average)  and  6.6 ug/day  (high).   Estimates  of  total  thor-


acic deposition are  slightly  higher.   Alveolar  and  total thoracic  deposition


under high  exposure  conditions  1n the 1960s were estimated  to be  as  high  as


100 and 152 ug/day, respectively.


    3.6.4.2.   INGESTION — Humans   Ingest   manganese   from   three   main


sources:   diet,  drinking  water and  Inhaled  particles  cleared  from  the


respiratory tract.


    No  recommended  dally  allowance  has   been   established  for  manganese,


although 1t  1s  recognized  as  essential (U.S. FDA, 1978).   Various estimates


have been made of average dally  dietary  Intake  of manganese by adults 1n the


United States (Table 3-31); most  recently,  average  consumption was estimated


by  the  U.S.  FDA  (1978).  This  estimate  was based on a  market  basket survey


of  117  frequently  eaten  foods (the  "Total  Diet — Adult")  collected  1n 1976


1n  four  United  States  geographic   regions.   The  diet, Including  drinking


water,  was   analyzed  for  several  minerals,   Including  manganese.   Results


expressed 1n terms of  caloric Intake were  1.28 mg Mn/1000  Calories.   At the

3000  Calorie/day  Intake  recommended  for  a 15  to 18-year-old male,  average
1797A                               3-84                             5/03/83

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1C
                                                          TABLE  3-30

                            Estimates of Human  Inhalation  Exposure  to Manganese 1n Ambient A1r*


w
1
03
tn




Exposure Type
1982 average



1982 high

1960s high

Deposition Site
alveolar
total thoracic


alveolar
total thoracic
alveolar
total thoracic
Ambient Concentration
(ug/m3)
0.023
0.023


0.661
0.661
10
10
Fine/OS
0.28
—


0.66
--
0.66
—
DS/TSP
0.56
0.56


0.76
0.76
0.76
0.76
Inhalation
(m3/day)
20
20


20
20
20
20
Exposure
(ug/day)
0.072
0.26


6.6
10.0
100
152
        *See text for explanation and qualifications.
fO

V.
oo

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                                  TABLE  3-31

                   Dietary Intake of Manganese 1n the U.S.
          Group
Average Dally Intake
        (mg)
      Reference
Adults, college women

Adults

Adults, males

Adolescents (15-18 years),
  males
      3.7

      2.3-2.4

      3.3-5.5

      3.8
North et al., 1960

Schroeder et al., 1966

Upton et al., 1969

U.S. FDA, 1978
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      3-86
              5/03/83

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manganese  Intake would  be  3.8 mg/day.   Assuming a body weight of 70 kg, this
amounts  to an Intake of  -0.054 mg/kg/day.   It should be  kept  1n  mind that
substantial  variability 1n real  Intake  levels 1s expected,  as  discussed 1n
Section  3.6.3.  The dally   Intake  of  manganese  by  bottle  and  breast-fed
Infants  1s  much  lower  because of the low concentrations of manganese  In both
breast and  cow's milk  (Table  3-32).   Manganese Intake Increases with  age, as
the  type  of  feeding  changes,  from  0.002-0.004  mg/kg/day  1n  Infants,  to
0.06-0.08 mg/kg/day  1n  children.
     In public  water  supplies, the median manganese  concentration  at  the  tap
1s   4 >ig/8.   (see  Table  3-29).   Assuming  dally  adult  consumption   of  2 8,
of water,  1t  1s  apparent  that the resulting manganese Intake of 0.008 mg/day
was  a  very  small  contribution  to  the  above  "Total  Diet" estimate  of   3.8
mg/day.   On the  other  hand,  manganese concentration  at  the  99th percentlle
1n  private  wells  was  977   jig/8.,   and  therefore  1t  should be  recognized
that  In   extreme  Instances   the  drinking  water  contribution (=2.0  mg/day)
could be  substantial.   This  contribution could be even  more  substantial  for
small  children  consuming   1 9,/day  (~1 mg   Mn/day),   when   compared  with
dietary  Intakes  for  children  (see  Table  3-32).   In  most  cases,  however,
drinking water 1s not  a significant contributor  to  manganese 1ngest1on when
compared to diet.
    Clearance  of  particles from the  respiratory  tract  1s an  even  smaller
source.   Even  assuming  100%  deposition  and  clearance to  the  gut  of  Inhaled
partlculate manganese,  current  ambient exposure (see  Table 3-30)  results  1n
0.00026  mg/day (average)  or  0.010  mg/day  (high).   High  ambient  exposures
during  the 1960s  could have resulted 1n the 1ngest1on of -0.15 mg/day.
1797A                               3-87                             5/03/83

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                                                            TABLE  3-32


                                            Intake of Manganese from  Food  by  Children
oo
CO
o
10
oo
CO
Age
1 week
0-3 months
1 month
1 month
3-4 months
5-6 months
3-5 years
7-9 years
10-13 years
3 months-8 years
9-12 years
Type of Feeding
NR
NR
breast milk
cow's milk
mixed feeding
mixed feeding plus
cow's milk
mixed feeding
mixed feeding
mixed feeding
mixed feeding
Institutional diet
Dally Intake
of Mn 1n mg
0.0064
NR
0.011
0.024
0.2
0.4
1.4
1.7
2.2
NR
2.0
Dally Intake
of Mn In mg/kg
Body Weight
0.002
0.002-0.004
NR
NR
NR
NR
0.08
NR
0.06
0.06
NR
Reference
Wlddowson, 1969
Belz, 1960
McLeod and Robinson, 1972
McLeod and Robinson, 1972
McLeod and Robinson, 1972
McLeod and Robinson, 1972
Schlage and Wortberg, 1972
Belz, 1960
Schlage and Wortberg, 1972
Alexander et al. , 1974
Murthy et al., 1971
NR = Not reported

-------
    Therefore, for  all  practical  purposes, Ingestlon of manganese  1s deter-
mined  solely  by  diet.   Estimates  for  average  exposure  range  from  2.3-5.5
(see Table  3-31),  but  some variability should be  expected  due to the widely
varying manganese content of foodstuffs.
3.7.   SUMMARY OF GENERAL PROPERTIES AND BACKGROUND INFORMATION
3.7.1.   Chemical  and  Physical  Properties.    Manganese   1s   a  ubiquitous
element  1n  the  earth's  crust,  1n  water  and  1n  partlculate  matter  1n  the
atmosphere.    In  the ground  state, manganese  1s  a gray-white metal resembling
Iron,  but  harder and  more brittle.  Manganese  metal  forms  numerous alloys
with Iron, aluminum and other metals (Matrlcardl and Downing, 1981).
    There are  numerous  valence states  for manganese, with  the divalent form
giving the most  stable  salts and  the  tetravalent form giving the most stable
oxide.   The  chlorides, nitrates  and  sulfates of  manganese (II) are highly
soluble  1n   water,   but  the   oxides,   carbonates  and  hydroxides  are  only
sparingly soluble.  The  divalent  compounds are  stable 1n add solution,  but
are readily oxidized  1n  alkaline conditions.   The heptavalent  form 1s found
only 1n oxy-compounds (Re1d1es, 1981).
3.7.2.   Sampling and  Analysis.   Sampling of  manganese  1n  ambient  air  may
be  carried   out   by  any  of  the methods used  for  collecting  atmospheric
partlculate   matter.    High-volume  samplers  with  glass  fiber  filters  are
widely used  by  the NASN  and by  state  and local  agencies  (Thompson, 1979).
                                          3
These  samplers  usually  filter   -2500   m  of   air  1n  a  24-hour   sampling
period.  High-volume samplers  may also  be operated with filters composed  of
organic membrane.
    If Information  on  particle   size  1s  desired,  other types of  sampling
devices are used.   Currently,  the  type  most  widely used 1s  the dlchotomous
sampler,   which  separately collects  fine  (<2.5 um)  and   coarse  (>2.5 vim)


1797A                               3-89                             5/03/83

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particles.   The upper size limit of coarse particles may  be  set  at  10,  15  or
20 urn  by  a  size-selective  Inlet.    Particles  are  usua>ly  collected  on
teflon  filters,   and sampling  time  varies  from  2-24  hours  (Dzubay and
Stevens, 1975;  U.S.  EPA,  1981a).
    Sampling of  source  emissions  presents  special  problems  related to gas
temperature and flow rate, which affect choice  of  filtering medium,  sampling
rate and  sampling equipment.   Isok1net1c or  equivalent  flow  rate  Into the
sampling probe  Insures  representative  sampling;  membrane filters  are not
used at high temperatures; and collection of condensate after  the filter may
also  be necessary   to  prevent  complications.   Automobile  exhaust  may  be
diluted with air  to  prevent  condensation  In  the  sampling train.
    Water,  soil and  food  are  collected for  manganese  analysis by  the  usual
techniques  Insuring  representative sampling without  contamination.   Biologi-
cal materials  such  as  urine,  blood,  tissues,  hair,  etc., are collected and
stored so  as  to  prevent contamination by dust; no  other  special procedures
are required when  sampling for  manganese analysis.
    Sample preparation prior  to  analysis  1s  necessary  unless  a  non-destruc-
tive analytical technique 1s used.  Solid samples  may  be  add  digested,  with
or without  prior  ashing  of organic matter.   Extraction of partlculate  from
glass  fiber  filters  1s done  by  Bonification  1n  heated,  mixed add  without
ashing (U.S. EPA,  1983a).
    Manganese 1n  an  aqueous sample  may  be preconcentrated by  evaporation  of
the liquid  (Boutron  and Martin,  1979).   If  other  Interfering  substances are
present, however, a  preseparatlon step may  be required.  Preseparatlon may
be accomplished by chelatlon,  1on  exchange or  copredpHatlon.
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    One  of  the  most  popular  analytical  techniques   for  metals  Including
manganese  1s atomic  absorption  spectrophotometry  (AAS).  Optical  emission
spectrometry  (OES)  has  been  used  for  analysis of  metals  from  glass  fiber
filters;  Inductively  coupled argon  plasma  (ICAP)  1s   the  excitation  method
currently used by EPA with this  technique (U.S. EPA, 1983b).
    The  above are  destructive  methods.   Non-destructive  analytical  tech-
niques  used  1n  multi-elemental  analysis  are  X-ray  fluorescence  (XRF)  and
neutron activation analysis (NAA).  XRF  Is  the most commonly  used method for
analysis of partlcultes on membrane filters.
    The detedon limits  for any  technique  vary according to sampling method,
sample  preparation and analytical  method.   Detection  limits for manganese 1n
                                  3
air  are  as  low as   0.002  ug/m  (Dzubay   and  Stevens,  1975;  U.S.  EPA,
1979a).
3.7.3.   Production  and  Use.   Very  Uttle  manganese  1s  mined  1n  this
country; some 1s mined  domestically  as  low-grade  ores,  but  most 1s Imported.
Manganese alloys,  manganese  metal  and many  compounds  of manganese  are pro-
duced  and  used  1n  the  United States,  however.   Ferromanganese  and  sH1co-
manganese are  ferroalloys produced  by  the  smelting  of manganese ore  1n  an
electric  furnace   (Matrlcardl   and   Downing,   1981).    Manganese  metal  1s
produced  by  add  leaching of  the  ore,  precipitation  of  other  metals  and
electrolysis of  the solution.  Manganese  alloys  and  metal  are  then  used  to
Introduce manganese Into steel or nonferrous alloys.
    Metallurgy,   especially   steel   making,  accounts   for  -95%  of  United
States demand for  manganese   (Reldles, 1981).   Ferromanganese  production has
decreased from  1148xl03  tons in  1965  to  <120xl03 tons  1n   1982.   SIHco-
                                                 3                          3
manganese production  has  decreased   from  284x10   tons  1n 1968  to  <75xlO
tons 1n 1982.  Demand for  these  products has diminished recently and Imports
are  Increasing  (Jones,   1982;  OeHuff and  Jones,  1981;  DeHuff,  1961-1980).

1797A                               3-91                              5/03/83

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The remaining  5-6% of manganese  demand  1s for a  number  of compounds  which
are  Important   1n   the   chemical  Industry  and  1n   battery   manufacture.
Manganous oxide (MnO), produced by reduction of manganese dioxide  ore,  1s  an
Important  precursor   for   compounds  used  as  feed  additives,   fertilizers,
colorants  and  chemical   Intermediates.    Electrolytic  MnOp,  also  produced
from MnO,  1s  used  1n dry-cell battery manufacture.   Potassium  permanganate,
produced  by   oxidation  of  MnO   ore,  1s  an  Important oxidizing  agent  and
catalyst (Reldles,  1981).
    Methylcyclopentadlenyl manganese trlcarbonyl  (MMT)  has  been produced and
used 1n  small quantities  as  a fuel additive  since  1958.   Major  use  as  an
octane Improver  1n unleaded  gasoline (at 0.125 g Mn/gal) began In 1974, but
was  discontinued  1n  1978  due to  adverse  effects   on catalytic  converter
performance and  hydrocarbon emissions  (U.S.  EPA,  1977b).  MMT continues  to
be used at -0.05 g/gal 1n  -20% of leaded gasoline  (Hall,  1983).
3.7.4.    Sources of  Manganese 1n the  Environment.   Manganese  1s  the  12th
most abundant  element and  fifth  most  abundant  metal  1n the earth's  crust.
While manganese  does  not  exist free 1n  nature,  1t 1s a major  constituent 1n
at  least  100  minerals  and  an accessory  element  In  more  than  200  others
(Hewett,  1932).   Its concentration  1n various  crustal components  and  soils
ranges  from  near zero  to 7000 ug/g;  a  mean  soil content  of  560  ug/g has
been given (Shacklette  et  al.,  1971).   Crustal  materials  are  an  Important
source  of atmospheric  manganese  due  to  natural  and  anthropogenic activi-
ties  (e.g.,  agriculture,   transportation,  earth-moving) which  suspend  dusts
and  soils.   The  resulting aerosols  consist primarily of  coarse particles
(>2.5 y.m)  (Ozubay, 1980;  Dzubay et al.,  1981).
1797A                               3-92                             5/03/83

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    Manganese 1s also released to the atmosphere  by  manufacturing  processes.



Ferromanganese  furnace  emissions  are composed  mainly  of  fine  partlculate



(<2.5 y.m)  with  a  high  manganese content  (15-25%).    Ferroalloy  manufacture



was the largest manganese emission source  1n  1968 (U.S.  EPA,  1971).   Current



estimates are not available, but control technology  has  Improved  and  produc-



tion volume has diminished.  Iron and steel manufacture  Is  also an Important



manganese   source.    Manganese   content   of   emitted  particles  1s   lower



(0.5-8.7%),  but  overall  production  volume  Is greater  than  for  manganese-



containing ferroalloys.



    Fossil  fuel combustion also results  1n manganese release.   The manganese



content of  coal  1s 5-80  ug/g  (U.S.  EPA,  1975).   Fly ash  Is about equal  to



soil 1n  manganese  content (150-1200 ug/g),  but  contains particles finer  1n



size.  This  1s  an  Important manganese  source because of the volume  of coal



burned each  year.   Combustion  of residual oil 1s less  Important  because  of



Its  lower  mangnese content.   About  15-30%  of manganese  combusted   In  MMT-



contalnlng gasoline 1s emitted  from the  tailpipe.



    The relative  Importance  of emission  sources   Influencing manganese con-



centration at a given monitoring  location  can be  estimated by  chemical mass



balance  studies.   Studies  1n   St.  Louis  and  Denver suggest  that  crustal



sources are more Important  1n  the coarse  than  1n the fine  aerosol fraction.



Conversely, combustion sources  such as refuse Incineration  and  vehicle emis-



sions predominantly affect the  fine  fraction.  In an  area  of  steel  manufac-



turing, the  Influence of  this  process was seen  1n both the fine  and coarse



fractions (Dzubay,  1980; Dzubay et al.,  1981;  Alpert and Hopke, 1981; L1u  et



a!., 1982).
1797A                               3-93                             5/03/83

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    Another means of  determining  the Influence of  noncrustal  sources 1s  to
compare  the  ratio  of  manganese  and aluminum  1n  an  aerosol  with  that  1n
soils.  The derived enrichment factor (EF)  Indicates the magnitude of  Influ-
ences from noncrustal sources.  In most areas EF  for coarse  aerosols  1s  near
unity, Indicating crustal  origin,  but EF  for  the fine fraction  1s  substan-
tially higher,  Indicating  a  greater  Influence from  noncrustal  sources  of
emission.
3.7.5.   Environmental  Fate and Transport  Processes.   A general  overview  of
man's Impact on  the  geochemlcal  cycling  of manganese  shows  a  nearly  doubled
flux  from  the  land  to the  atmosphere  due  to  Industrial  emissions,  and  a
tripled flux from land to oceans, via rivers, due  to  soil  loss from  agricul-
ture and  deforestation (Garrels  et al.,  1975).
    Atmospheric manganese 1s present  1n several forms.  Coarse dusts  contain
manganese  as oxides,  hydroxides or  carbonates  at low  concentrations  (<1  mg
Mn/g).  Manganese from smelting or  combustion  processes 1s  often present  1n
fine  particles with  high concentrations  of manganese  as  oxides  (up  to  250
mg/g).   Organic  manganese  usually  1s not  present  1n   detectable concentra-
tions (Coe et al.,  1980).
    Oxides of  manganese  are  thought to  undergo  atmospheric  reactions  with
sulfur dioxide or  nitrogen  dioxide  to give the divalent  sulfate or  nitrate
salts (Sullivan,   1969).   Manganous  sulfate  has been  shown  to catalyze  SO
transformation  to  sulfurlc  add,  but  the manganese concentration  necessary
for a significant  catalytic effect  has been  disputed   (Wright  et al., 1973;
P1ver, 1974).
    Atmospheric manganese  1s  transported  by  air  currents  until  dry  or  wet
deposition occurs.   In New  York City, dry deposition   occurred more  quickly
for manganese  than  most  other  metals,  because  H tended  to  be present  In
1797A                               3-94                             5/03/83

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                                                                           2
 larger  particles.   Dry  deposition  of  manganese  averaged  300-670  ng/cm /
                                                  2
 month,  whereas  wet  deposition  was   ~120  ng/cm /month   (Klelnman  et  al.,
 1975;  Volchok  and  Bogen,  1973).   Over  much  of  the  United  States  1n
                                                                      2
 1966-1967,  wet  deposition  of  manganese  ranged  from <10-540  ng/cm /month
 (Lazrus  et  al.,   1970).   Near  a  ferromanganese  plant   1n  1964-1965,  dry
 deposition was as high as  19,300 ng/cm2/month (NAPCA, 1970).
     In water or soil,  manganese  1s  usually present as the divalent or tetra-
 valent form.   Divalent  manganese  (present  as  the hexaquo  1on)  1s soluble and
 relatively  stable 1n  neutral  or acidic  conditions.  Chemical  oxidation  to
 the  Insoluble  tetravalent form takes  place  only at  a  pH above 8  or  9, and
 chemical  reduction  of  the  tetravalent  form  occurs  only at  pH   <5.5.   At
 Intermediate   pH,   1nterconvers1on  occurs   only   by  mlcroblal   mediation
 (Alexander, 1977).
     Manganese  tends  to  be  mobile  In  oxygen-poor  soils and 1n the groundwater
 environment  (Mitchell,  1971).   Upon  entering   surface  water,   manganese  1s
 oxidized  and  precipitated, primarily by bacterial  action.   If  the sediments
 are  transported   to  a  reducing  environment  such  as  lake bottom,  however,
 mlcroblal  reduction  can occur, causing re-release  of divalent  manganese  to
 the  water column  (Kuznetsov, 1970).
     The  concentration  of  manganese 1n  lower  organisms 1s much  higher  (by a
             3    4
 factor  of 10  -10  )  than  In  the  surrounding  water.   However,  the  concen-
                                 2
 tratlon  factor Is   lower  (10-10  )  as  trophic  level Increases,  Indicating
 that  the  element  1s  metabollcally   regulated.    Thus   blomagnlf1cat1on  of
manganese does not occur (Lentsch et al., 1972).
 3.7.6.   Environmental  Levels  and  Exposure.   Nationwide air   sampling  has
been  conducted  In   some   form  since  1953  (U.S.   DREW,   1958).   Analytical
methodology has  Improved  and monitoring  stations  have  changed,  complicating
1797A                               3-95                             5/03/83

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any analysis of  trends  In manganese  concentration.   However,  H  1s  evident


that manganese concentrations 1n ambient air have declined  during  the period


of record.  The arithmetic mean manganese concentration  of  urban  samples  was


0.11  vig/m3  1n  1953-1957  (U.S.   DHEW,  1958),  0.073  ug/m3  1n  1966-1967
(McMullen  et  al.,  1970),  and  decreased  to  0.033  ug/m3  by 1982  (Barrows,


1983).   In 1953-1957,  the  percentage  of   urban  stations  with  an  annual

                      3
average  of >0.3  v-9/m  was  ~10%.   By  1969  these  had dropped  to <4%,  and

since 1972 the number has  been <1%.


    The  highest  manganese concentrations,  with  some  observations  exceeding

        3
10  ug/m ,  were  seen 1n  the 1960s  1n areas  of ferromanganese  manufacture
(NAPCA,  1970;  U.S.  DHEW,  1967).   More  recent measurements  1n these  areas


Indicated decreases of at least an order  of  magnitude  had occurred,  although


definitive studies were not  available.


    In most cases where comparable data on  total  suspended  partlculate  (TSP)


were available, decreases 1n  TSP  also  occurred, but were usually  smaller 1n


magnitude  than  those for manganese.   This  would  suggest that  the  observed


reductions 1n  manganese  were  more than a simple reflection of  TSP  Improve-


ments, Indicating specific reductions of manganese emissions.


    Techniques  for  characterizing  particle-size  distributions  for  trace

metals  1n ambient  aerosol  are  only recently  available.  Studies  Indicate


that   manganese   1s  associated   with   both   fine   (<2.5 y.m)  and   coarse


(>2.5 y.m)  particles  (Bernstein and  Rahn,  1979).   The manganese  concentra-


tion In each fraction 1s  highly variable.   On  the  average,  <16% of manganese


1n aerosol mass 1s found  1n fine  particles;  however,  1t  1s estimated that 1n


some situations the fine fraction  could contain as much as 50%.
1797A                               3-96                             5/03/83

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    Manganese  concentrations   1n  nonpolluted  freshwaters  are  usually  <20
     ,   but  may   exceed   1000   ug/&   where  polluted.    The  amount   of
manga- nese  1n  suspension  exceeds  the amount 1n  solution,  except where add
mine  drainage   1s  prevalent  (Kopp  and  Kroner,   1969).   Concentrations  1n
ground- water typically are higher  than In surface water (Hem, 1970).
    Three  surveys  of  United  States  drinking water  supplies  have  provided
data on  manganese  concentration  (Durfor  and  Becker,  1964; U.S. DHEW,  1970;
Greathouse,  1983).   Although  concentrations   >1000  vig/8,   are   found  1n
some, notably  private,  water  supplies,  -95% of  all  supplies  contain manga-
nese  at   <100  ug/fc-   A  median   concentration   of  4  iig/fc for   public
supplies has been  reported (Greathouse, 1983).
    Total  human exposure  to manganese  may  be estimated from  Information on
levels  1n  air,  water and  diet.   Inhaled  particles  can be  deposited either
extrathoradcally,  1n  the  tracheobronchlal  region, or  1n  the  alveoli.   Time
required for particle clearance and  probability  of absorption Increases with
Increasing  depth  of  deposition 1n  the  respiratory  tract  (U.S. EPA,  1982).
Deposition  of  manganese 1n the  alveoli  can  be  calculated from the  ambient
concentration  and   the  fraction   present   1n   fine  particles.    Thoracic
(tracheobronchlal  plus  alveolar)  deposition 1s calculated  from estimates of
the  manganese  found   1n particles  <15  um 1n  size.   Alveolar  deposition of
manganese  at current  ambient levels   1s  estimated   as  0.072  v-9/day  as  an
average  and  6.6 ug/day under  high  exposure conditions.   Estimates  of  total
thoracic  deposition  are  slightly  higher;  0.26  vig/day  (average)  and  10.0
lig/day   (high).   Alveolar  and  total   thoracic   deposition   under  the  high
                             3
exposure conditions  (10 vig/m  ) of  the  1960s  were estimated  to be  100 and
152 ug/day,  respectively.
1797A                               3-97                             5/09/83

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    Diet 1s the main source of Ingested manganese.  Average  adult  Intake  has
been variously estimated  at  2.3-5.5 mg/day.   On  a body-weight basis,  expo-
sure Increases from  0.002-0.004  mg/kg/day 1n  Infants to  0.06-0.08  mg/kg/day
1n adults.   Drinking water usually comprises only  a very  small  proportion of
total  1ngest1on  exposure.  The  median Intake  level  via  drinking water  1s
~0.008  mg/day,   but   can  be  as  high  as   -2.0  mg/day   for   some  water
supplies.   The 1ngest1on  of particles  cleared  from the respiratory  tract 1s
an even smaller source, probably  constituting  no  more than  0.01  mg/day under
the highest ambient exposure conditions currently  observed.
1797A                               3-98                             5/03/83

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                   4.  BIOLOGICAL ROLE AND PHARMACOKINETICS
4.1.   BIOLOGICAL ROLE OF MANGANESE
    Manganese was shown  to  be essential for growth  and  reproduction 1n rats
and mice as early as  1931  (Kemmerer  et  al.,  1931;  Orent and McCollum, 1931).
Later 1t was demonstrated that manganese  prevented  a skeletal  abnormality 1n
chickens called  perosls  (Wllgus  et al., 1936).  Although  manganese  has been
shown  to be  essential   for  many  species  of  animals,  as  yet  there are  no
well-defined occurrences of manganese deficiency 1n humans (Prasad, 1978).
4.1.1.   Biochemical  Role.   Extensive   Information   1s   available   on  the
Interaction between  manganese and proteins  (Leach and  Lllburn,  1978; Utter,
1976; Prasad, 1978).  The  relationship  between manganese  and  enzymes can be
classified  Into  two  categories,  metalloenzymes  and metal-enzyme  complexes
(Leach,  1976).   The  first  category  of  enzymes 1s  very  limited, while  the
enzymes that can be activated are numerous.
    Glycosyl  transferases  are Important  enzymes 1n  the  synthesis  of  poly-
saccharldes and  glycoprotelns,   and  most  of  these enzymes  require manganese
for normal activity (Leach,  1971, 1976).
    There 1s substantial experimental evidence that  an  Impairment 1n glycos-
amlnoglycan  metabolism   1s  associated  with  several  symptoms  of  manganese
deficiency (Leach and Lllburn, 1978).
    The  most  extensively studied  manganese metalloenzyme 1s  pyruvate  car-
boxylase (Scrutton et al.,  1972).   Magnesium was found  to replace manganese
as  the bound metal to pyruvate carboxylase Isolated  from manganese-deficient
chicks.
4.1.2.   Manganese Deficiency.   Manganese deficiency  has  been  demonstrated
1n mice,  rats,  rabbits  and guinea  pigs.   The main  manifestations  of manga-
1804A                               4-1                               4/29/83

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nese deficiency  are  those associated  with skeletal abnormalities,  Impaired
growth,  ataxla  of   the   newborn,  and  defects  1n  I1p1d  and  carbohydrate
metabolism.
    The  skeletal abnormalities  of  manganese  deficiency are  described  as
abnormally  fragile  bones, with  shortening  and bowing  of  the  forelegs  1n
mice,  rats  and rabbits (Amdur et al.,  1945;  Ellis et al.,  1947;  Plumlee  et
a!., 1956).  This disease 1s  known  as perosls  1n chickens.
    Manganese deficiency during pregnancy  1n rats  and  guinea pigs  produces a
congenital defect In  the  young characterized  by ataxla  {Hurley,  1968;  Ever-
son et al.,  1959).   This  defect  1s  usually associated with  loss  of  equilib-
rium, Increased susceptibility to stimuli, head retraction and tremors.
4.1.3.    Manganese Requirements.   The minimum  dally  requirements of  manga-
nese for   laboratory  animals   vary  with  the  species  and  genetic strain  of
animal, the composition of diet and the criteria of adequacy employed.
    Mice,  rats  and   rabbits   are  unable  to   grow normally on  milk  diets
containing  0.1-0.2  ppm manganese.    The  minimum requlrment  for manganese  1n
the  diet  of mice  has not been  established,   but  diets  containing  50  mg/kg
manganese  were  adequate  for  growth  and development  of  several  genetic
strains  (Hurley  and  Ther1ault-Bell,  1974).    Although   the requirement  of
manganese  for   development  and  growth   has   not  been  adequately  studied,
Holtkamp and H111  (1950)  concluded that  50 ppm manganese In diet 1s optimum
for rats.
4.1.4.    Summary.  Although  manganese  has been shown  to  be essential  for
many species  of  animals,  as  yet  there  are  no well-defined  occurrences  of
manganese  deficiency  1n  humans.   Manganese deficiency has been  demonstrated
1n  mice,  rats, rabbits and  guinea  pigs.  The  main manifestations of manga-
nese deficiency  are   those associated with skeletal  abnormalities,  Impaired


1804A                               4-2                              05/06/83

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 growth,  ataxla  of  the newborn,  and defects 1n I1p1d and carbohydrate metabo-
 lism.    Although  the  dally  requirement   of  manganese  for  development and
 growth  has  not  been adequately  studied,  1t  was  accepted that diets contain-
 ing  50  mg/kg manganese are adequate for most of the laboratory animals  (MAS,
 1978).
 4.2.    COMPOUND DISPOSITION AND  RELEVANT PHARMACOKINETICS
 4.2.1.    Absorption.   The  main  route of manganese  absorption 1s  the gastro-
 intestinal  (GI)  tract.  Absorption  through  the  lung  1s  considered to be an
 additional  route  1n  occupatlonally  exposed  workers and  1n residents living
 1n  Industrialized areas  with  higher  ambient  air  concentrations of manganese.
 Skin  absorption of   Inorganic  manganese  1s  not  considered  to  occur  to  a
 significant  extent.
    4.2.1.1.   GASTROINTESTINAL  ABSORPTION — Food  1s  generally  the  main
 source  of manganese.   Therefore,  the  GI  tract  1s the  portal  of  entry  of
 manganese and  the  absorption from  the  GI  tract  1s  the  first step  1n manga-
 nese  metabolism.   Human and  animal  studies  show  that  on  an  average  ~3% or
 less  of a  single  dose  of radlolabeled manganese 1s  absorbed  from  the  GI
 tract Irrespective of  the amount of stable carrier.
    4.2.1.1.1.   Human  Studies  — Mena  et  al.   (1969)   studied   manganese
 absorption  1n  11  healthy  fasted human  subjects  by administering 100  uC1  of
 4MnCl?  with  200  ug  stable   55MnCl2  as  a  carrier.    On  the  basis  of
whole body  counts  performed  dally for  2  weeks  the  absorption  of    Mn was
calculated  to  be   an  average  of  -3%.   Similar  absorption  values  were
obtained  1n  six  healthy  manganese  miners   (-3%)  and  six  ex-miners  with
chronic   manganese poisoning  (-4%).  These values  could be  an underestimate
of  the   absorption  because  enterohepatlc  circulation  was  not  taken  Into
account  but  the  authors considered  this  to  be Insignificant.
1804A                               4-3                              4/29/83

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    4.2.1.1.2.   Animal  Studies  —  In  an  early  study  using  rats  Greenberg



et al.  (1943) estimated  that  3-4% of  a single oral dose containing 0.1 mg of


54
  Mn  labeled  manganese  (as   chloride)  was  absorbed  from  the  Intestine.


                                                                         54
This  estimation  was  made  on   the  basis  of differences  1n  biliary    Mn



excretion  after  parenteral  and  oral  administration.   Pollack et  al.  (1965)


                                                           54
reported  2.5-3.5% absorption  of a  single oral  dose  of    Mn  (as  chloride



with  5 v.moles  stable  carrier)  1n   fasted rats.   They measured  whole-body



and  gut-free  carcass  radioactivity  6  hours   after  administration.   The



fraction apparently  absorbed  (I.e.,  the  gut-free  carcass  retention) could be



an underestimate  due to  the excretion Into the  Intestine.   Similarly, Rabar



(1976) and Kostlal et  al. (1978) reported  a 0.05% whole-body  retention value


                                         54
6  days  after  a  single  oral  dose  of    Mn  (as  chloride-carrier free)  1n



postweanlng  nonfasted  rats.   The very low value  observed  1n  their  experi-



ments  can  be explained  by  considerable  loss   of   the  absorbed  manganese



through  endogenous  fecal excretion within  6  days after  administration.   It



should also  be mentioned that higher values  obtained  1n  other  studies might



be due to administration of  the Isotope to fasted animals.



    Little 1s known  about mechanisms Involved 1n  manganese absorption.   The



IP. vitro  experiments performed by C1krt  and  Vostal  (1969) show  that  manga-



nese  absorption  1s  likely  to occur  1n  the  small  as well as  1n  the large



Intestine.   However, whereas  manganese 1s  actively transported  1n the small



Intestine, there  1s  only  simple  diffusion  1n  large Intestine.   Miller  et al.



(1972) found that  1n calves the  upper  sections of the small  Intestine  absorb


          54
far more    Mn  than  the  lower  sections.   Manganese excreted  Into  the  Intes-



tine  (biliary  excretion  being  the  most  Important)  1s known  to  enter  the



enterohepatlc circulation.  C1krt  (1973)  showed  that manganese  excreted 1n



the bile  1s  1n  a form more  easily  absorbed  than manganese  dlchloMde.   He
1804A                               4-4                              4/29/83

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found that the  Intraduodenal  uptake  of biliary excreted manganese  was about
35%, whereas  only 15% of an equivalent  dose  of  manganese dlchlorlde adminis-
tered Intraduodenally was absorbed.
    4.2.1.2.    RESPIRATORY ABSORPTION  — There  are  no  quantitative  data  on
absorption rates  for  Inhaled  manganese either  1n humans or  1n  animals.   It
1s assumed that  some  basic  principles considered  by  the Task Group on Metal
Accumulation  (TGMA, 1973) can be  applied to  Inhaled  metals  1n general.  Only
particles  small  enough   (usually  several  tenths  of  yon)  to reach  the alveo-
lar  lining are  likely to be  absorbed directly Into  the blood.   An unspeci-
fied fraction of  the metal Initially  deposited  1n the lung 1s expected to be
removed  by mucocllllary clearance and consecutively swallowed,  thus under-
going gastrointestinal absorption processes.
    4.2.1.2.1.   Human  Studies  — Mena et al.  (1969) performed  an  Inhala-
tion study In 21  human  subjects  exposed for  10 minutes  either to a nebulized
                      54
aqueous  solution  of     MnCl-   (7  normal  controls  and   10   exposed  working
                                                         54
miners)  or   to   a  nebulized   aqueous  suspension  of     Mn?°3  ^  exposed
miners).  The estimated  mean  particle  size of  the droplets delivered through
the  nebulizer was 1 v.m.  They  found  that  about  40-70%  (average  60%) of the
radioactivity  Initially  located   1n  the  lung  was  recovered  1n  the  feces
collected  within  4 days after  administration.   The fate  of  manganese oxide
was  Identical  to  that   of the  chloride.  On  the  basis of  regional radio-
activity  measurements  over  different  parts of  the thoracic  and  abdominal
cavities the authors assumed  that the GI  tract was a portal  of entry for the
Inhaled  manganese.  However,  as  stated by  the authors themselves, absorption
of  the  Inhaled  manganese  directly  from  the  lung cannot be excluded.   The
authors'  assumption seems  to  be highly  speculative and  experimental  data
presented  are  Incomplete.   Fecal  excretion  1s  the  main route  of  manganese
1804A                               4-5                              05/06/83

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excretion and  regional  measurements Indicating  the  movement of the  Isotope
through the body do not provide data concerning  the  direction  of movement  of
the Isotope through the  Intestinal  wall  (I.e., whether 1t  1s  being  absorbed
or excreted).
    4.2.1.2.2.    Animal    Studies  ~ Pertinent   data   regarding   manganese
absorption from  the  lung  1n  animals  could not  be  located  1n  the available
literature.
4.2.2.   Distribution  and  Normal  Tissue  Levels.  Distribution  1s  the  term
used to describe the uptake of  the  absorbed manganese  by  various  tissues and
organs 1n pharmacoklnetlc  studies  after  a single or repeated  administration
of  the radioactive  tracer.  Such data are almost always  obtained In animal
studies.   Human  studies  (generally  post-mortem analyses  of  various  organs
and  tissues)  reflect  the body  and organ burden  as  a  consequence  of  the
long-term (Hfespan)  Intake of this essential  element.
    4.2.2.1.    HUMAN STUDIES ~ A normal  70  kg man has a  total  of  12-20  mg
manganese  1n  the  body   (Cotzlas,  1958;   WHO,  1981).  Sumlno  et al.  (1975)
found  ~8  mg  manganese  1n  a  group of  30  Japanese cadavers  (15 males .and  15
females,   -40  years  old  with  an  average weight  of  55  kg).   Muscles  con-
tained  -30%,  liver  -20%,  and   the  digestive  tract  -15%  of  the  total
amount.   Manganese  tissue levels  1n  normal  humans   from three  different
studies (Kehoe et al.,  1940;  Upton  and  Cook, 1963;  Sumlno et al.,  1975) are
presented 1n Table 4-1  (WHO,  1981).  Although some  differences between these
studies  are  obvious  (probably  due  to  different  analytical  techniques used)
the  highest  concentrations  were  found   In  liver  and  pancreas (~1  vuj  Mn/g
wet weight or  more).   Kidney  concentrations  were between 0.6  and 0.9 y.9/9-
Lowest concentrations were found  1n  brain, heart,  lung,  Intestine and gonads
(usually  between  0.2  and  0.3>ig/g),   with  extremely   low  concentrations
(<0.10 ug/g) 1n muscles,  bone,  fat  tissue  and  spleen.

1804A                               4-6                               05/06/83

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CO
o
                   TABLE 4-1


Manganese In Human Tissues  (ug  Mn/g  wet  weight)
ro
oo
to
Kehoe et al., 1940
Tissue (emission spectroscopy)
Aorta
Brain 0.30
Fat
Heart 0.32
Intestine 0.35
Kidney 0.60
Liver 2.05
Lung 0.22
Muscle
Ovary
Pancreas
Spleen
Testes
Trachea
R1b
Tipton and Cook, 1963
(emission spectroscopy)
0.11
0.27
--
0.23
--
0.90
1.30
0.24
0.06
0.18
1.10
0.11
0.14
0.14
— _
Sumino et al., 1975
(atomic absorption)
--
0.25
0.07
0.21
—
0.56
1.00
0.22
0.09
0.19
0.77
0.08
0.20
0.20
0.06

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    In  spHe  of appreciable  Individual  variations  of  manganese  concentra-
tions 1n the  liver,  there  1s  little variation from one part of  the  liver  to
another (Perry  et  al.,  1973).  Normal brain  concentrations  1n adults up  to
0.6 y.g  Mn/g wet weight  were  reported (Fischer  and Uelgert,  1977).   Larsen
et al.  (1979) studied the topographical distribution of manganese  (As  and  Se
as well) 1n normal  human brain tissue.  Manganese was found  to be  associated
with  the dry  matter  of brain tissue  and,  related  to dry weight,  equal  con-
centrations were found  1n  white and  grey  matter.   They also  found  signifi-
cant  differences between 24  different brain  regions  studied.  Mean  values
were  within  the range  from  0.133-0.449  ug  Mn/g  wet  weight, with  highest
values  observed  1n   the  basal   ganglia   (I.e.,   nucleus  caudatus,   globus
palUdus and  putamen).   Similar results with  highest  concentrations  1n  the
basal ganglia were  also reported  by Smeyers-Verbeke  et al.  (1976).
    The levels  1n  biological  fluids  (blood and  urine  particularly) will  be
discussed  1n  Section 4.2.5.1. concerning  their  significance  1n relation  to
exposure.
    4.2.2.2.   ANIMAL STUDIES — Distribution  studies 1n  mice  (Kato,  1963),
rats  (Dastur  et al., 1969) and  monkeys (Dastur  et al.,  1971) show  a  high
uptake  of  radioactive manganese  by liver,  kidneys  and endocrine glands,  and
only minor  amounts  In brain  and  bone.
    When mice  were exposed to  MnO  by Inhalation  1n  concentrations  of  5.6
             3
and  8.9 mg/m   and  particle  size  of  3 vim for 2  hours  dally  for 8  and  15
days,  respectively,  the highest  concentrations  of  manganese  were found  1n
the  kidney (10.8  and 8.4  mg/kg  dry  weight),  liver  (9.0  and 7.1  mg/kg),
pancreas (8.4  and  8.2  mg/kg) and  brain   (5.9 mg/kg)  (Mourl,  1973).   After
1ntraper1toneal administration of  radioactive  manganese to rats,  the  highest
concentrations  were  found  1n the  suprarenal, pituitary,  liver  and  kidney
1804A                               4-8                              05/06/83

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tissue (Dastur et  al.,  1969).  The  uptake  by glandular structures was  also
high  1n  monkeys  after   1ntraper1toneal  Injection  of  radioactive  manganese
(Dastur et al., 1971).
    Scheuhammer and  Cherlan  (1981)  studied  regional  distribution  of  manga-
nese  1n  brains of  male rats.   Two groups  of six animals  each were  given
dally  1.p.   Injections   of   either  3   mg   Mn/kg  as  MnCl_»4H20_   or   an
equal  volume  of  0.9% NaCl  for  30  days.  Of  the  thirteen regions  examined,
the  highest  concentrations  1n normal rats  were  1n hypothalamus,  colUcull,
olfactory bulbs and  mldbraln.   In  treated  rats  all brain regions  showed  an
Increase,  the  greatest   being  1n  the  corpus   stMatum  which Increased  from
~1.7  to  8.8 mg/kg  dry  weight.   On  a percentage  basis the  highest Increase
was 1n the corpus callosum, 1300%.   This  study demonstrated  that under these
conditions manganese 1s  taken  up by strlatal, mldbraln and  thalanrtc  regions
at  a  greater  rate  than  other brain areas.   Thus, manganese  1s selectively
concentrated 1n areas  of the  extrapyramldal   system,  which  may explain  the
signs and symptoms of manganlsm.
    In  the  portal   blood  most  of  the  manganese may become  bound  to  a
a  -macroglobulln  and  removed   from the   blood   very  efficiently  by  the
liver.   A  small  proportion  becomes  bound  to transferrln,   and enters  the
circulation system  to  be transported  to the  tissues.   This oxidation  step
may  be performed  by ceruloplasmln (Gibbons et  al.,  1976).   Within  a cell,
manganese  1s  sequestered  by  mitochondria  (Maynard  and  Cotzlas,   1955).
Tissues  rich  In   mitochondria   (liver,   kidneys,   pancreas)  contain  higher
levels of manganese (Kato,  1963).
    The  early work of  Fore  and  Morton  (1952)  showed  the   constancy  of
manganese concentrations 1n different organs for  a large  number  of  species.
1804A                               4-9                              05/06/83

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From their data It 1s apparent  that  bones,  liver,  kidneys  and some endocrine
                                                                             'j
glands  (pituitary  In  particular)  carry  higher   manganese  concentrations
(1.2-3.3  ng  Mn/g wet  weight)  than  other  organs  and  tissues  (0.18-0.65
V.g/g).   Brain concentration was  0.40 vig/g  and this  value  1s  1n  agreement
with human values  already discussed.
4.2.3.   Excretion.    Manganese   1s  almost  totally  excreted  via  feces   1n
humans  and  animals   (Newberne,   1973;  WHO,  1981).   Amounts  of  manganese
excreted via  urine,  sweat and milk  are  negligible compared  to  fecal  excre-
tion.  Variable excretion 1s  assumed  to  be the main  mechanism  1n manganese
homeostasls (see Section 4.2.5.).
    4.2.3.1.   HUMAN  STUDIES — Quantitative   data   concerning   manganese
excretion 1n humans are not available  (WHO,  1981).   Urinary  excretion  1s  low
Indicating that only  a  small  fraction of the absorbed manganese 1s excreted
via  that  route.  Concentrations  In   urine  1n  unexposed  and  exposed  people
will be discussed  In Section 4.2.5.1.
    4.2.3.2.   ANIMAL STUDIES — Animal  studies clearly show  that  manganese
1s eliminated from the  body mainly via feces.   Greenberg  and Campbell  (1940)
                                                                 54
reported that  90.7% of a single 1ntraper1toneal dose of  1  mg   Mn to  rats
was found  1n  the  feces  within 3 days  after  administration.   In  a subsequent
study Greenberg et  al.  (1943)  Injected  1ntraper1toneally  0.01  or  0.1  mg of
54
  Mn  to  rats  and  found  that  27.1   and  37.3%  of  the  respective dose  was
collected  1n  the  bile within  48 hours.  After  Intravenous administration of
0.6  >ig  of  manganese  dlchlorlde  1n  rats  12% of  the  Injected  dose  was
excreted Into the bile  within 3  hours  (T1chy  et al.,  1973)  and 27% within 24
hours (C1krt, 1972).
    Adklns  et al.  (1980a)  studied   retention  and  subsequent  clearance  of
manganese after 2-hour  Inhalation exposure  of Charles  River  CD-I mice  to 1.8
1804A                               4-10                             05/06/83

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         3
mg  Mn/m   as   Mn»0.  aerosol,  with  average  mass   median  diameter  ~1.4
um.   Seven data points were  obtained 1n 24  hours,  each for  a  group of six
mice.   The exponential curve fit  to the  data  Indicated  that  -47,  27 and
14% of  the manganese remained 4, 6 and 24 hours after exposure, respectively.
    Klaassen  (1974)  estimated  the  biliary excretion  of manganese  1n rats,
rabbits  and  dogs after  Intravenous  doses  of  0.3,  1.0, 3.0  and  10.0 mg/kg.
At  the  three  lower  doses  the concentration of manganese 1n bile was  100-200
times  higher  than  1n  the  plasma.   Excretion  Into the  bile Increased as the
dose  Increased.   However,  after  a  dose of  10  mg/kg  there was  no  further
Increase  1n  excretion of  manganese   Into the  bile,  and a  maximum excretion
rate  of  ==8.5  ]ig/m1n/kg   was  attained.    This  Indicates   that  a  saturable
active  transport mechanism may exist for manganese.
    Although  biliary excretion  1s  particularly  Important  1n adjusting the
manganese  body load, bile  1s  not  the exclusive route of manganese excretion.
Under  ordinary  conditions,   the  bile  1s  the main  route  of excretion  and
represents  the principal   regulatory mechanism,   but  experiments  1n animals
show  conclusively  that manganese 1s  also excreted  through  the  Intestinal
wall  (Bertlnchamps   and  Cotzlas,  1958;  Kato,  1963;   PapavaslHou   et  al.,
1966).   In rats  there  1s  some  evidence  for  the  excretion of  manganese
through  the  Intestinal wall  Into  the  duodenum,  jejunum  and,  to  a lesser
extent,  the  terminal  1leum  (Bertlnchamps  et  al., 1966;  C1krt,  1973).   In
dogs  manganese 1s  also  excreted to  some  extent  with the  pancreatic juice
(Burnett  et  al.,  1952).   It  has been  shown  that  while  excretion  by  the
biliary  route  predominates  under normal  conditions,   excretion  by auxiliary
GI routes  may  Increase  1n  the presence  of  biliary obstruction or  with over-
loading of manganese  (Bertlnchamps et al., 1966;  PapavaslHou et  al., 1966).
1804A                               4-11                              4/29/83

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    Urinary excretion  Is  low.   Klaassen (1974)  found  that  1n  rats 5  days
after  Intravenous  dosing 99% of  administered manganese  was eliminated  1n
feces  and  only  0.1%  In  urine.   Biliary  obstruction  or  overloading  with
manganese  did  not   Increase  the  urinary  excretion  (PapavaslHou  et  al.,
1966).  Moreover, the authors found that  animals  with rectal  obstruction did
                                          54
not  excrete  measurable  quantities   of    Mn  via  urine  within  the  5-day
observation period.   Only after  Injection  of  EDTA (ethylene  dlamlnetetra-
acetlc add)  did urinary excretion  become  predominant  for  24  hours,  after
which  time fecal elimination  was  resumed  (Kosal  and Boyle,  1956; Maynard and
F1nk,  1956).
4.2.4.   Biological Half-time.
    4.2.4.1.   HUMAN  STUDIES —  Mahoney   and  Small  (1968)  showed   that  the
disappearance rate  of  labeled manganese  from  the  body  of  three normal  human
subjects can  be described by  a  mathematical  expression which  1s  the sum of
two  exponential  functions.   Each of  these processes can  be  characterized by
a  "half-time",  one  of  which  was  4 days and  another which was 39 days.  About
70%  of the  Injected  manganese was excreted  via the slower pathway.  In three
other  subjects  with  a higher  oral  Intake of manganese, a  higher  rate of
elimination was observed.
     Cotzlas et  al.  (1968) studied the tissue  clearance  of manganese  1n three
groups  of   humans:   healthy  subjects, healthy  manganese miners  and miners
removed  from  manganese exposure  but  with chronic manganese poisoning.  After
          54
a  single   Mn  Injection  they found  a different total  body  turnover of  the
label  for  the  three  groups:   37.5,  15 and 28 days,  respectively.   Regional
determination of  radioactivity of the liver,  head and  thigh showed differ-
ences  among  various  body areas  and   differences  among groups.   The corre-
sponding turnover  times for  the  three groups  were:  1n the liver 25, 13  and
26 days; In the head  54,  37  and  62 days;  and 1n  the thigh 57, 39 and 48  days.

1804A                              4-12                              05/06/83

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    4.2.4.2.   ANIHAL STUDIES — Brltton and  Cotzlas  (1966)  reported a  two-
component whole body clearance rate  for  manganese  1n  mice.   The half-time of
the  fast component  was  10  days  and of  the  slow component,  50  days.   A
10-fold  Increase 1n  the dietary  Intake of  manganese decreased the half-times
of the  Isotope  by  about 50%.  The effect  of  dietary  manganese levels on the
terminal elimination of manganese  1n  mice  was studied by Suzuki (1974).  The
animals  received an  aqueous  solution  of  manganese  chloride  1n concentrations
ranging  from 20-2000  mg/4  for   30   days  before  radlomanganese  administra-
tion.   The  whole  body clearance  half-time was estimated at  about  6 days 1n
the  lowest   concentration  group.   It decreased  to  3  days  at a  manganese
concentration  of   100  mg/9.  and   to  about  1  day   1n  animals   receiving  2000
mg/8..   The  half-time of manganese In the  brain was found to  be  longer than
for the  whole body.   This was also shown  for  rats  (Oastur et al.,  1969) and
for monkeys  (Dastur  et  al.,  1971).   In  rats  the half-time  1n the  whole body
was estimated  to  be  14  days, and  1n the  brain  1t could not  be  determined
during  the  observation  period of  34  days.  In monkeys  the half-time 1n the
brain could not be determined after  278  days  of observation,  while the whole
body half-time was  estimated  to be 95 days.
4.2.5.   Homeostasls.  As pointed  out by Rehnberg  et al. (1980),  the normal
human adult  effectively  maintains tissue manganese at  stable levels despite
large variations  In  manganese Intake.   Although  some workers  maintain that
this  homeostatlc  mechanism  1s   based  on  controlled  excretion (Brltton  and
Cotzlas, 1966;  Hughes  et  al., 1966;  Leach,  1976), a critical  review of the
evidence reveals  that manganese homeostasls   1s  regulated  at  the  level  of
absorption   (Abrams et  al.,  1976a,b)   as  well  as at the  level  of  excretion.
1804A                               4-13                             05/06/83

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For Instance, Lasslter et al.  (1974) have  provided  evidence  that the dietary



manganese level has a  greater  effect on manganese  absorption  than  on excre-



tion of endogenous manganese and  that both  variable excretion  and absorption



play  Important  roles   1n  manganese  homeostasls.   In  addition,  manganese



absorption 1n rats 1s  related  to  the dietary  manganese  level  (Abrams et al.,


                                     54
1976a,b).    In   these   experiments     Mn   absorption  and  metabolism  were



studied 1n rats fed diets containing 4  ppm (basal), 1000 ppm and 2000 ppm of


                                                                    54
unlabeled manganese  several  days prior  to a  single  oral  dose  of    Mn.   At


                                                           54
different time  Intervals after  oral  administration, the   Mn  concentration



was  determined 1n  various  tissues.    Four  hours  after administration  all


                                                                 54
tissues  from rats  fed the basal  diet  continued to  have higher   Mn concen-



tration  than  tissues  of  rats given  higher  unlabeled manganese  1n diet.  The


                                          54
effect  of dietary  manganese  on tissue    Mn  concentration  following  oral



dosing  Indicates  that  variable absorption  1s  an Important factor  1n manga-



nese homeostasls  (Abrams et  al., 1976b).   From  4-24 hours  after administra-



tion  of   low  and  high manganese  diets  to  rats,  the relative  difference  1n


54
  Mn  concentration  Increased  1n many  tissues.  This  confirms  that  higher


                                                        54
levels  of  unlabeled  dietary  manganese  accelerates     Mn  turnover  after



absorption  and  tissue  deposition.   Suzuki  (1974) reported  an  Intestinal


                                  54
absorption of  only  0.5-1.97% of   Mn  1n  mice prefed diets having  levels  of


                                                       54
MnOp  ranging from  20-2000   mg/kg.   The retention  of    Mn  observed  In  the



whole body was Inversely proportional to the dietary manganese level.



    Absorbed manganese is almost  totally excreted via  the  Intestinal wall  by



several routes, and  these  routes are interdependent and combined to provide



an efficient  homeostatlc mechanism.  Robert (1883)  and Cohn  (1884)  are cited



by von  Oettingen  (1935)  as  the first to observe that  manganese, after large



injected  doses, was mainly excreted  in  the  feces and only  traces appeared In
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 urine.   Subsequent  experiments  with  rats at  a  lower  level  (a  1  mg  dose)
 showed  that 90%  of  the  1ntraper1toneally  admlnstered dose  appeared  1n  the
 feces within 3  days  (Greenberg and Campbell,  1940).
     IntraperHoneal  administration  of 0.01 mg  manganese  to rats resulted  1n
 the  biliary excretion of 27% of  the  dose within 48 hours;  a dose  of 0.1  mg
 resulted  1n 37%  appearing  1n the  bile   (Greenberg  et  al., 1943).   Klaassen
 (1974)  estimated  the  biliary excretion  of  manganese  1n  rats,  rabbits  and
 dogs  after  Intravenous doses of 0.3,  1.0,  3.0  and 10.0 mg/kg.  At the  three
 lower doses, the  concentration  of  manganese 1n  bile was 100-200 times higher
 than  that  1n  the plasma.   Excretion Into  the bile  Increased as  the   dose
 Increased.  However,  after  a dose  of  10  mg/kg,  there was no  further Increase
 1n  excretion  of  manganese  Into the  bile, and  a  maximum  excretion  rate  of
 -8.5  vig/m1n/kg  was   attained.   This  finding  Indicates  that an  apparent
 maximum  transport rate  may exist  for manganese.   Aut1ss1er  et al.  (1982)
 recently  demonstrated that  the  IntraperHoneal  administration of  the   same
 high  dose  of   manganese (10  mg  MnCl?/kg  bw)  for  a  period  of  4  months
 resulted  1n Increased  brain accumulation of  manganese  1n  rats.  This manga-
 nese  treatment  gave  rise to  significant  Increases In  the  concentrations  of
 manganese 1n brain stem  (359%), corpus  strlatum  (243%),  hypothalamus (138%)
 and "rest of the brain"  (119%).
    The efficient  operation of  the  homeostatlc mechanism  1s  also  reflected
 by  the  fact  that tissue manganese  accumulation  differs  depending   on  the
 routes of administration of this metal.   Thus, the results  of Aut1ss1er et
 al.  (1982)  contrast  with those  of  Chan  et al.  (1981)  and  Rehnberg  et al.
 (1982).   The results  from Rehnberg et al.  (1982), summarized  1n Table  4-2,
demonstrate  that the dose-related Increases In  manganese  levels In  brain and
1804A                               4-15                             4/29/83

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  CD
  o
r\j
vo
CO
03
                                                                               TABLE 4-2

                                                        Concentrations of Manganese 1n Liver, Kidney and  8ra1na
                                                                                 wet weight)

Manganese
Concentrat1onb
(ppm)
50
400
1100
3550

24

2.1
4.0
6.7
17.0

40

2.0
2.6
2.8
4.6

60

2.1
2.6
2.5
3.5
Liver
100
(days)
2.2
2.7
2.6
3.3

115

2.0
2.5
2.4
3.1

135

2.8
3.7
3.4
4.7

224

2.9
3.0
3.4
4.0

24

0.6
0.9
1.5
2.6

40

1.3
1.3
1.4
2.0

60

1.0
1.1
1.2
1.2
Kidney
100
(days)
0.8
1.1
1.0
1.0

115

0.6
0.7
0.8
0.9

135

0.9
1.2
1.2
1.5

224

1.0
1.2
1.2
1.2

24

0.5
0.8
1.4
2.7

40

0.5
0.6
0.7
1.1
Brain
60 100 130
(days)
0.4 0.4
0.5 0.4
0.6 0.4
0.7 0.5

224

0.4
0.4
0.4
0.5
            aAdapted from Rehnberg et a!., 1982

            bMn304 1n diet

-------
kidney resulting  from chronic  feeding with manganese  varying from  50-3550
ppm were not quite as high as one  might  anticipate.   Chan et al.  (1981)  only
observed a  small  Increase  (31%)   1n  brain manganese  concentration 1n  rats
exposed  to  278 ppm  Hn  as  MnCl   1n  the  drinking  water for  over 2  years.
Liver values were  up 45%.
    The concentrations of manganese 1n the  liver  are  probably related  to the
specific  mechanism  of  biliary excretion of  manganese.   Klaassen  (1974)
demonstrated that manganese  1s  excreted Into  the bile  against a  concentra-
tion  gradient.   On  the  other  hand,  T1chy and  C1krt (1972)  suggested  that
manganese may  be  transferred from plasma  Into the bile  by  passive transfer
followed  by a  nonenzymatlc  complex   formation   1n  the  bile.   However,  1n
contrast to bile, plasma  and liver contain Ugands with higher  affinity for
manganese (Klaassen,  1974).   Thus,  the transfer  of manganese  from plasma to
bile may be mediated by  an active mechanism.
    Although normally biliary excretion 1s  particularly Important  1n regu-
lating the  body burden  of manganese,   this   route  of excretion 1s  by no means
exclusive.  This  1s because  experiments In animals  and  humans  conclusively
demonstrate  that  manganese  1s   also   excreted  through  the   Intestinal  wall
(Bertlnchamps  and  Cotzlas,  1958;   Kato,   1963;   PapavaslHou  et   al.,  1966;
Wassermann  and  Mlhall,  1964).   For  Instance,  there   1s  some Indication  of
manganese excretion  through  the rat  Intestinal  wall  Into the duodenum,  the
jejunum  and,  to  a  lesser extent,  the terminal  1leum  (Bertlnchamps  et  al.,
1966; C1krt, 1972).   Both of these  routes of  excretion contribute signifi-
cantly toward the homeostasls of tissue  contents  of manganese.   In addition,
manganese 1s also excreted to some extent  with the pancreatic juice (Burnett
et al.,  1952);  manganese  excretion  by auxiliary GI  routes  may  Increase 1n
the  presence of  biliary  obstruction  or  with manganese  overloading (Bertln-
champs et al.,  1966; PapavaslHou et al., 1966).

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    4.2.5.1.   LEVELS  IN  BIOLOGICAL  FLUIDS  AND  BIOLOGICAL  INDICATORS  OF


EXPOSURE — Concentrations  of  the  metal  In  biological  media  have  been


studied as  Indicators  of  exposure.   The correlations between  the  manganese


contents  1n  blood and  urine  and  the  findings  of neurological  symptoms and


signs have also been examined.   Manganese concentrations  1n  body fluids have


not, however, proven to be reliable Indicators of exposure.


    The mean concentration of manganese  1n  the  urine  of  nonexposed  people 1s


usually  estimated  to   be between  1  and  8  v-9/fc,  but  values  up  to  21


V.g/8.  have  been  reported (Hor1uch1  et  al.,  1967;   T1chy   et  al.,  1971).


Tanaka  and   Lleben  (1969) have  shown  that  a  rough  correlation  may  exist


between mean  urinary levels   and  average occupational air concentrations  of


manganese, but 1n Individual   cases  the correlation  1s  poor.   Hor1uch1  et al.


(1967) and  Chandra  et  al. (1981)  have  also  associated  Increased mean urine


manganese levels with Increased levels of manganese 1n the air.


    Recent  studies  that  used  neutron activation  and electrothermal  atomic


absorption analytic procedures have shown that  the  average normal  concentra-


tion  of  manganese  1n  whole  blood 1s  0.7-1.2  ixg/100  m&,  and that  manga-


nese  concentration  1s   much   higher  In  the  erythrocytes  than  1n  plasma  or


serum  (Cotzlas  et al.,  1966; Cotzlas and  Papavas1l1ou,  1962;  Papavas1l1ou


and  Cotzlas,  1961;  PapavaslHou  et  al.,  1966;  MuzzarelH  and  Rocchettl,


1975; Buchet et al., 1976; Tsalev  et  al., 1977;  Z1elhu1s et  al., 1978; Olehy


et al.,  1966).   The average   manganese blood  level 1n exposed  workers seems


to be of  the same order  as that  In nonexposed persons,  but some observations


Indicate  that heavy  exposures  to manganese  may  Increase  the  level  of  manga-


nese  1n   the  blood.   Tsalev  et  al.  (1977)  found  that  workers exposed  to

                           3
=1 mg  of  manganese dust/m   of  air,  for  a  period  of  1-10 years,  had blood
1804A                               4-18                             4/29/83

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 levels  of manganese  averaging 11-16  ]ig/A  compared to  a mean  level  of 10


 iig/9.  1n  nonexposed  persons.   Variations  In  plasma  manganese concentra-


 tions  1n women may be  associated with hormonal  changes  (Hagenfeldt et  a!.,


 1973).   Slight  seasonal  (HoMuchl et al.,  1967)  and diurnal (Sabadas, 1969)


 variations  1n blood  manganese concentrations  (lower during  summer,  autumn


 and  at  night)  have also  been reported.   Manganese concentrations  did  not


 differ  among adult age  groups (Hor1uch1  et al.,  1967)  and several studies


 Indicate that there  1s  no difference  1n the  concentration  of manganese 1n


 the  blood of  men  and  women (HoMuchl et al., 1967;  Zhernakova, 1967; Mahoney


 et al.,  1969; Versleck et al., 1974).


     There  1s  only one study  Indicating a correlation between  the manganese


 blood  and urine  levels and  the  findings  of  neurological  symptoms and signs


 (Horluchl  et al.,  1970).   Using  the  results  of medical  examinations   per-


 formed  1n three  groups  of workers employed  1n  crushing  manganese ore, manu-


 facturing  dry-cell  batteries  and  electrodes, Hor1guch1 et  al.  (1966), found


 a  tendency toward anemia  as  determined  from the specific  gravity  of whole


 blood, a  decrease  1n white  blood  cell  count, and an Increase 1n neurological


 findings.  A  significant  association was  reported (p<0.05)  between the urine


 manganese  level  and  the  neurological  findings  for  all  the  groups  taken


 together.  In the manganese ore-crushing  workers  (the group with  the highest


 mean  exposure),  a  significant association  was determined  between manganese


 levels 1n  the whole blood and  urine  and 1n  the neurological findings.   Other


 Investigators reported that  the manganese of blood  1s unrelated  to  clinical


 neurological  findings  (Rodler,  1955;  Penalver, 1955).


    The  determination of  manganese  1n  feces has  been recommended as a group


 test for  the  evaluation  of the level  of  occupational exposure to manganese
                                            »

 (J1ndr1chova, 1969).  Manganese  content  1n  hair  1s  normally  below 4  mg/kg






1804A                               4-19                             4/29/83

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(Eads and Lambdln,  1973).   There  1s as yet  no  consensus  on  other  biological
materials which could be used to monitor  manganese  exposure.   Chandra et al.
(1974) suggested using  serum  calcium to diagnose early exposure,  and subse-
quently  found  an  Increase  1n calcium  1n exposed  welders  (Chandra  et  al.,
1981).
4.2.6.   Summary.   On  the  basis  of human  (Mena et  al.,  1969)  and  animal
data  (Pollack  et  al.,  1965; Kostlal et al., 1978)  H  1s  generally accepted
that  -3% or less  of  a  single  oral dose of  manganese  1s absorbed  from the
GI  tract  under  normal  conditions.    There are neither human  nor animal  data
suggesting the rate of  absorption  of manganese through the lung.
    Manganese  1s  widely distributed within  the body 1n  constant  concentra-
tions which are characteristic for  Individual  tissues and almost  Independent
of  the   species  (Fore  and  Morton,   1952).   The  concentration of  manganese
present  1n  Individual tissues, particularly  1n  the  blood,  remains  remarkably
constant  1n spite  of  some rapid phases 1n manganese  transport. The average
normal  level  of  manganese  1n  whole  blood  of  humans  1s 7-12 y.g/8.,  while
the manganese  levels  In serum are  normally  distributed around a  mean value
of  0.5-0.6  u.g/8,  (Versleck  and  Cornells,  1980).    The   highest   values  of
manganese In humans are  found 1n liver,  kidney  and  endocrine glands which do
not  exceed  2  ug/g wet  weight  of   tissue.   Manganese penetrates  the blood-
brain and placental barrier.  Animal data Indicate a higher  manganese accu-
mulation  1n suckling animals,  especially 1n  the brain (Kostlal et al., 1978).
    Fecal excretion 1s  the  most  Important way  of manganese  elimination from
the   body.    Biliary   excretion  1s  predominant   under   normal   conditions
(Klaassen,  1974) although excretion  via  pancreatic  juice  and Intestinal wall
are  considered  to be  Important  1n conditions  of  biliary  obstruction  or
manganese overload (PapavaslHou  et al.,  1966).   In humans  and  1n animals
urinary excretion  1s low (Klaassen,  1974).

1804A                               4-20                             05/06/83

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    The  total  body clearance  of manganese  1n  humans  can be  described  by a
curve which  1s  the  sum of  at least two exponential functions with half-times
of  4  and 40 days, respectively.   However,  the  physical  significances of the
estimated half-times cannot be obtained from this data.
    Manganese metabolism  1s  rigorously controlled by homeostatlc mechanisms.
The  homeostatlc  control  1s  primarily exerted  at  the  level  of  excretion;
however,  the site of  GI  absorption  may also be  an  Important control point.
The absorption,  retention  and excretion of  manganese  are  closely  linked and
Interrelated  and  respond  very  efficiently  to  an  Increase   1n  manganese
concentration.   The  GI absorption  depends  not  only on the  amount  Ingested
and  tissue   levels of  manganese, but  also on manganese  b1oava1labH1ty and
Interaction  with  other metals.  The way  tissue  concentrations Influence the
excretory mechanism  1s still  unknown.   B1le Is  the most  Important route of
excretion.
4.3.   SYNERGISTIC/ANTAGONISTIC  FACTORS
    The  way  1n  which  the  body normally  handles  manganese  1s  affected by the
age of  the   Individual and  by  the status  of other metals 1n  the  body.   The
effect of Iron stores has  been the subject of several studies.
4.3.1.   Interaction with  Metals.
    4.3.1.1.   HUMAN  STUDIES —  Thomson  et  al.  (1971)  studied  the  Intesti-
nal transport system for manganese and Iron 1n  subjects  with three different
levels of  Iron  stores:   those with normal  Iron stores,  patients  with  Iron
deficiency,   and  patients  with  endogenous  Iron  overload.  Administration of
manganese by a  duodenal  sonde  1n  these  patients  showed that  the  rate  of
absorption was  Increased  1n Iron-deficient  patients and  that  this  enhanced
absorption could be Inhibited by addition of Iron.
1804A                               4-21                              4/29/83

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    Recent balance  studies  performed  1n humans  showed  no effect of  dietary
calcium on manganese  balance.   Price  and Bunce  (1972)  studied  the  Influence
of calcium  Intake  (300-1300 mg  dally)  on  the balance  of several  essential
elements  Including  manganese  1n 7-  to  9-year-old  girls.   The  researchers
concluded that  the  calcium Intake 1n  this  study had no  effect  on  manganese
balances.
    4.3.1.2.    ANIMAL  STUDIES  — Considerable   Investigation  has  been  made
of the  relationship between Iron and manganese.   The addition  of  manganese
to  diets  of  several  species   of  animals  depleted  of  Iron  resulted  1n
depressed  hemoglobin   levels.   WHgus  and   Patton  (1939)   reported  that
addition of  ferric  citrate  to  the diet accentuated  the  severity of perosls.
Matrone et al.  (1959)  found that excessive manganese 1n  the diet  (2000 ppm)
depressed  hemoglobin  formation  1n  both  rabbits  (-88%  of  control  levels)
and baby  pigs  (-50%  of control  levels).   The  minimal level of  manganese  1n
the diet  that  Interfered with  hemoglobin  formation  was  estimated to  be  50
and 125 ppm,  respectively.
    The  Interaction  of  Iron  and  manganese  metabolism 1n  rats  was  also
studied by Dlez-Ewald et al.  (1968).   When Iron absorption was  Increased  1n
Iron deficiency,  manganese absorption  was  also  Increased.   Decreased  Iron
absorption 1n  Iron   loaded  animals  was  associated  with  decreased  manganese
absorption.  The  body  compensated  for  changes In  manganese  absorption  by
Increasing  manganese  excretion  1n   Iron-deficient  states  and  decreasing
manganese excretion  In Iron loaded states.
    Kostlal  et  al.   (1980)  found that  Increasing   the  Iron  content  of  milk
                                                            54
decreased the whole body  retention  of  orally  administered    Mn by a factor
of 10  1n  rats  fed milk with or  without  100 ppm Iron additive.   Thomson and
Valberg  (1972)  and  Thomson et  al.  (1971)  studied  the   Interrelationship  of
1804A                               4-22                             05/06/83

-------
the  Intestinal   transport  system  for   manganese  and  Iron  by  using  the
technique of  open-ended  duodenal  loops  1n  control and  Iron-deficient  rats.
They found  that  manganese  competes  with Iron and  cobalt  1n  the  process  of
uptake from the  lumen  Into the mucosal  cells and  1n  the transfer  across the
mucosa Into the body.
    Manganese Interaction  with other elements  such as  Zn,  Cu, Cr,  Co,  Cd,
N1, In,  Rh  and  Se have also been  described  (Doyle  and Pfander, 1975; Jacobs
et  al.,  1978; Burch  et   al.,  1975;  Schroeder  et  al.,  1974;   Schroeder  and
Nason,  1976).  Most  of these  Interactions  occurred at  the  level  of  gastro-
intestinal absorption  and  under  specific  conditions,  I.e.  the  concentrations
of  other  nonessentlal  elements  exceeded  the normal levels by  several orders
of magnitude.   These Interactions  are not discussed because  of their  limited
relevance to evaluating the human health  risk of manganese Inhalation.
4.3.2.    Effect of Age.
    4.3.2.1.   HUMAN  STUDIES -- Several   studies  Indicate  that  age   1s  an
Important  factor  1n  manganese absorption  and retention  starting with  the
fetal   stage  through  adult  life.   Studies   by  Schroeder et  al.  (1966)  and
Wlddowson et  al.  (1972)  confirm  that human placenta!  transfer  of manganese
takes  place.
    In contrast   to  some   other  essential  metals,  manganese  levels  1n  the
fetus  and  newborn are similar  to adult  levels  (Fischer and  Vlelgert,  1977;
Casey   and Robinson,  1978).  The  exception  seems  to  be  bone, where  fetal
concentration  1s  higher than  1n the  adult  (Casey  and  Robinson, 1978; Sumlno
et  al.,   1975).   In  fetal  liver  and  kidney,  concentrations   of  -0.94  and
0.45 mg/kg  have  been  found  (Casey  and  Robinson, 1978).   In  the  newborn,
corresponding  values  were  0.52 and  0.48  mg/kg,  respectively  (Fischer  and
1804A                               4-23                             05/06/83

-------
Welgert, 1977).  Wlddowson et  al.  (1972)  reported that  there  was  no  consis-



tent change  In  the liver with age  1n  30  fetuses  from 20 weeks  of  gestation



to full term but that generally manganese concentrations  1n  full-term livers



were 7-9% higher than concentrations 1n adult livers.



    In  contrast  to many  other  trace metals,  manganese  does  not  accumulate



significantly 1n the  lungs with  age (Newberne, 1973).   In lungs of  both the



adult  and  the  fetus,  average concentrations  of  -0.2  mg/kg  manganese  have



been  reported  (Schroeder  et  al.,  1966;  Sumlno  et  al.,   1975;  Casey  and



Robinson, 1978).



    Data  reported  by  Fischer and  Welgert  (1977)   Indicate  a  tendency  to



decreasing renal manganese levels  above age 50.  Data reported  by  Schroeder



et al.  (1966) show  a  difference  between subjects  20-49 and  50-59 years  of



age.   Anke and  Schneider  (1974)  report a slightly higher mean concentration



of manganese In females  than  1n males.



    Several studies  Indicate  that  manganese  penetrates  the placental  barrier



and  that  manganese  Is  more  uniformly distributed  1n  fetal  than 1n  adult



tissues  (Koshlda  et  al.,  1963;  Onoda et  al.,  1978).   Koshlda found  that



fetal tissue concentrations of manganese except kidney and liver were higher



than concentrations  of  comparable  adult tissue.  Onoda et al.  (1978) found,



however, that  all  measured fetal  tissues  (Including  kidney and  liver)  had



higher  concentrations  of manganese.   At  a  later embryonic   stage  manganese



accumulation takes  place parallel  to ossification  (Koshlda et al.,  1963).



    4.3.2.2.    ANIMAL STUDIES —  Rabar  (1976)  and  Kostlal   et al.   (1978)



observed much  higher  manganese absorption  1n artificially fed suckling  rats


                                         54
than  in adult  animals.   Absorption of   Mn  in  older  animals  fed  on  milk



diet was also  higher (6.4%)   than  1n rats  on control diet (0.05%)  but never



as high  as  1n newborn  rats.    These  results  Indicate that both  age  and  milk
1804A                               4-24                             4/29/83

-------
 diet  cause very  high absorption  (40%)  of  manganese In  the  Immature.  The



 addition  of  manganese  to  milk  decreased  the  percentage of  absorption of


 54
  Mn   In  both  suckling  and  adult  rats,   Indicating  the  existence   of  a



 homeostatlc control  mechanism 1n neonates which,  however,  seemed to be  less



 effective 1n  newborns.



    Miller  et al.  (1975)  found  that  neonatal  mice did not excrete manganese



 for  the first 17-18  days  of life, although absorption  as well as distribu-



 tion,   tissue  accumulation  and  mltochondrlal  accumulation  of  elemental



 manganese  was vigorous.   This   suggested an Initially  avid  accumulation of



 manganese  that  was supplied  1n  trace amounts  1n  the  mouse milk  (54 ng/mi).



 The  presence  of   high  absorption  coupled  with  the absence  of  excretion



 resulted  1n  a  marked  rise  of  tissue  manganese  1n the neonates  from an



 exceedingly low to a very high level.



    Ihe  tissue  accumulation 1n  the brain was  particularly Impressive as the



 brain  can be  susceptible  to both manganese  poisoning and deficiency.  Miller



 and  Cotzlas  (1977)  noticed  an  absence  of  manganese  excretion  during the



 first  18 days of  life  1n  neonatal  rats and  kittens.  However, when lactatlng



 mothers  were  given drinking  water  with  concentrations  of manganese ranging



 from  40-40,000  mg/ft, the  lactation  barrier appeared to  give  adequate pro-



 tection  to  the young.   When the  level  exceeded  280 mg/9.,  newborn animals



 Initiated  excretion  before  the  16th day of  life.   The  neonates  showed  a



 greater accumulation  1n  the brain  than  their  mothers,  whereas  the Increase



 In liver concentrations was proportional  to the concentrations  found  1n the



 liver of their mothers.



    Kostlal  et  al.  (1978)  found  a difference  between 54Mn distribution 1n



the  newborn  as compared  to  older rats.   Most  striking  was  the  34  times



higher manganese uptake  1n  the  brain of  6-day-old  sucklings as  compared to









1804A                               4-25                              4/29/83

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adult females.  These  findings  suggest that  the  neonatal  brain may be at  a
higher  risk  of  reaching  abnormal  concentrations  than are  other  tissues.
Rehnberg et al. (I960) found that the  tissue  distribution  of  manganese  oxide
In  preweanllng  rats  after oral  exposure was:   liver  >  brain » kidney  >
                                                                     t
testes at  18-21  days  of age.   Subsequent  studies of  longer  duration  (Rehn-
berg et al., 1981, 1982) gave similar  results  and Indicated  the dietary Iron
deficiency caused a greater accumulation of tissue manganese.   These authors
concluded  that maximum  manganese  oral  absorption   and  retention  1n  rats
occurs  during  the  preweanllng   period.   CahUl  et   al.  (1980)  found  that
preweanllng rats  retained  up to  12 times more  manganese  when  the  chloride
was Ingested compared  to the oxide.
4.3.3.   Summary.    It  1s  generally accepted  that  under  normal  conditions
3-4% of orally Ingested manganese 1s absorbed  1n  man (Mena et al., 1969)  and
other mammalian species  (Pollack  et al.,  1965).   Gastrointestinal  absorption
of manganese and  Iron may  be competitive  (Mena et al., 1969;  Kostlal  et al.,
1980).  This  Interaction  has a  limited relevance to human  risk  assessment
under normal conditions.   However,  1t  does lead  to the hypothesis  that  Iron-
deficient  Individuals  may  be more  sensitive  to manganese  than  the  normal
Individual.
    Evidence  1s   accumulating  that  during mammalian development  manganese
absorption  and  retention   are  markedly  Increased  (Kostlal   et  al.,  1978)
giving  rise  to Increased  tissue  accumulation of  manganese   (Cahlll et  al.,
1980; Chan et al., 1983).
    Manganese  does  penetrate   the  blood-brain   barrier  and   the  placenta!
barrier.   Studies 1n  animals  Indicate a  higher  manganese concentration  1n
suckling animals, especially In  the  brain (Kostlal et al.,  1978).
1804A                               4-26                             05/06/83

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                    5.   TOXIC  EFFECTS  AFTER  ACUTE  EXPOSURE
5.1.    ANIMAL STUDIES
    The  average  median  lethal   doses  (LIL-)  observed  1n  different  animal
experiments are presented  1n  Table 5-1.  These  data Indicate  some  variance
among  LD    doses  reported  by different  researchers,  which  may be  attrib-
uted  to  the  specific  experimental  design   used  (I.e.,  route  of  exposure,
chemical  form,  animal  species,  or even  age of  animals).   Generally,  oral
doses  are  much  less toxic  than  parenteral  doses.   The  average  LDV-  values
range  from 400-830   mg  Mn/kg  for  oral  administration of  soluble  manganese
compounds and from 38-64 mg Mn/kg  for parenteral  Injection.   These  data also
show  that  the toxldty  of manganese  varies with  the  chemical  form  admin-
istered to animals.   It has been suggested  that  catlonlc manganese  forms are
more  toxic  than  the anlonlc forms  and that  the  bivalent cation  1s  ~3 times
more  toxic than a trlvalent cation  (U.S.  EPA,  1975).   Although  the  permanga-
nate anlons are strong oxidizing agents which  show  some  caustic action, they
are  relatively  less  toxic than  the catlonlc  forms.    Obviously,  Insoluble
manganese  oxide  Is   less  toxic  than several  of  the soluble  compounds  (Hoi-
brook  et al., 1975).   However,  as  seen from Table  5-1,  1t  1s  very  difficult
to conclude  from  the data how the  type of  manganese 1on Influences  Its tox-
1c1ty.  Comparative  1ntraper1toneal  toxldty studies have  shown  that  manga-
nese  1s  less toxic  than  many other  metals (Franz, 1962;  Blenvenu et al.,
1963).
    Kostlal  et  al.   (1978)  found  that  age   plays  an Important  role  1n  the
pharmacoklnetlcs  and toxldty of heavy metals.  The highest  oral  toxldty of
manganese was found  In  the oldest  and youngest groups of  rats,  as  Indicated
1n Table  5-2.   In  3- and  6-week-old  rats  a  sharp  decrease 1n  toxldty was
noted  when  compared to  sucklings; LD__  values  were  Increased by  a  factor
0591B                               5-1                               05/06/83

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o
LTI
                 TABLE 5-1


Acute 1050  Values  for Manganese Compounds
in
i
r\j
(\3
00
CO
Compound Valence
Manganese 2+
chloMde
Manganese 2+
acetate
Potassium 7+
permanganate
Manganese 4+
dloxlde
Manganese 2+
sulfate
Manganese 2+
nltrate
Manganese 2+
chloride
Exposure
Route
oral
oral
oral
oral
oral
oral
oral
oral
oral
oral
l.p.
1.p.
l.p.
1.p.
1.p.
Animal
mouse
rat
guinea pig
rat
rat
rat
mouse
rat
guinea pig
rat
mouse
mouse
mouse
mouse
rat
LD50
(mg Mn/kg)
450
425
400
410
475
836
750
750
810
7400
44
64
56
53
38
Reference
S1gan and VUvlckaja,
S1gan and VHvlckaja,
S1gan and Vltvlckaja,
Holbrook et al., 1975
Kostlal et al., 1978
Smyth et al., 1969
Sigan and Vltvlckaja,
S1gan and VHvlckaja,
Sigan and Vltvlckaja,
Holbrook et al., 1975
Blenvenu et al. , 1963
Yamamoto and Suzuki,
Yamamoto and Suzuki,
Franz, 1962
Holbrook et al.. 1975

1971
1971
1971

1971
1971
1971

1969
1969


-------
                                  TABLE 5-2

                Influence of Age on Manganese ToxIcUy In Rats:
                    LD5o Values 8 Days after a Single Oral
                           Administration of MnCl?*
Average and Range of
Age 1n Weeks MnCl2 • 4H20
2 804 (735-897)
3 1860 (1655-2009)
6 1712 (1553-1887)
18 850 (775-957)
54 619 (564-702)
LDso (mg/kg) Values
Actual Mn Dose
223 (204-249)
516 (459-557)
475 (431-524)
236 (215-265)
171 (156-194)
'Source:  Kostlal et al., 1978
0591B
5-3
4/21/83

-------
of  2-3.   In adult  rats  toxldty Increased  again  and reached values  1n  the
oldest animals similar to  those  of  suckling  rats.   The researchers suggested
that older  rats might be more  susceptible  to metal  toxldty due to a general
decrease  1n adaptive responsiveness,  which  1s  characteristic  of  the  aging
process.  It  Is  difficult  to evaluate the contribution  of  aging  because  the
animals  were  only  about  1 year old.   Increased toxldty  1n suckling  rats
might occur as a  result of  higher  Intestinal manganese absorption and higher
body retention, observed earlier by some authors (see Chapter 4).
5.2.   HUMAN STUDIES
    Acute poisoning  by manganese 1s very rare.  It  may  occur In  exceptional
circumstances  such  as  accidental or  Intentional  1ngest1on of  large amounts
of  manganese  compounds.   Dagll et  al.  (1973) described a  case where exten-
sive damage to the  distal  stomach,  resulting In pylorlc  stenosis, occurred 2
hours  after  Ingestlon  of  potassium  permanganate   (10  tablets   of  300  mg
each).   Mahomedy  et al.   (1975)  reported two  cases  of  lethal  methemoglobl-
nemla Induced by potassium permanganate prescribed  by African witch doctors.
    Manganese,  along with  other  metals  such  as   zinc,  copper,  magnesium,
aluminum,  antimony,  Iron,  nickel,  selenium,  silver  and  tin,  has  been
reported to cause metal  fume fever  1n humans.  Metal  fume  fever  1s an acute
effect  of   occupational  exposure  to   freshly  formed  metal  oxide  fumes  of
resplrable  particle  size.   The  symptoms  are  similar  to those of Influenza
consisting  of  fever,  chills,   sweating,  nausea,  and  cough.  The  syndrome
begins 4-12 hours  after  sufficient exposure and  usually lasts for  24  hours
without  causing  any permanent  damage.  The  mechanisms are not fully under-
stood (Plscator,  1976).
0591B                               5-4                              4/26/83

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5.3.   SUMMARY
    The  average  LD    observed  1n  different  animal  experiments  Indicates
that  the  oral  dose values  range  from 400-830 mg Mn/kg  of  soluble manganese
compounds,  much higher  than  the  38-64  mg  Mn/kg  for parenteral  Injection.
The  toxldty of  manganese varies  with  the chemical  form  1n  which  1t  1s
administered  to animals.   Acute  poisoning  by  manganese  1n  humans  1s very
rare.   It  may  occur following  accidental  or Intentional  1ngest1on  of large
amounts  of  manganese   compounds.   Along  with  a   number   of  other  metals,
freshly formed  manganese  oxide  fumes  have been  reported  to cause metal fume
fever.
0591B                               5-5                              05/06/83

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>EPA
               United States
               Environmental Protection
               Agency
                Office of Health and
                Environmental Assessment
                Washington DC 20460
EPA-600/8-83-013
June 1983
External Review Draft
     lfr 2.
               Research and Development
Health Assessment
Document for
Manganese

Part 2 of 2
 Review
 Draft
 (Do Not
 Cite or Quote)
                             NOTICE

               This document is a preliminary draft. It has not been formally
               released by EPA and should not at this stage be construed to
               represent Agency policy. It is being circulated for comment on its
               technical accuracy and policy implications.

-------
                                               EPA-600/8-83-013
                                               External Review Draft
                            DRAFT
                     Do not dte or quote
                  HEALTH ASSESSMENT DOCUMENT
                             FOR
                          MANGANESE
                            Notice

This  document   1s  a  preliminary  draft.   It  has  not  been
formally released  by EPA  and  should not  at this  stage  be
construed  to  represent  Agency  policy.   It  1s  being circu-
lated for  comment  on Us  technical  accuracy  and  policy Im-
plications.
             U.S. ENVIRONMENTAL PROTECTION AGENCY
              Office of Research and Development
        Office of Health and Environmental Assessment
         Environmental Criteria and Assessment Office
                    Cincinnati, OH  45268
           Project Managers:  Dr. Linda S. Erdrelch
                              Dr. Oerry F. Stara
       U.S. !""• '•'.-•
       r

-------
                                      DISCLAIMER







       This  report  1s an  external  draft  for  review purposes  only and  does  not



   constitute Agency  policy.   Mention  of trade names or  commercial  products does



   not constitute endorsement or recommendation for use.
U,S,
                                          11





    1794A                                                                5/06/83

-------
                                    PREFACE
     The Office  of  Health  and  Environmental  Assessment  of  the  Office  of
 Research and Development  has  prepared  this Health Assessment Document  (HAD)
 at  the request of  the  Office  of A1r Quality Planning and  Standards  (OAQPS).
 Manganese  1s one  of  several metals and  associated compounds emitted to  the
 ambient air which  are  currently being studied  by the Environmental  Protec-
 tion  Agency to determine  whether  they should  be  regulated as hazardous  air
 pollutants  under  the  Clean A1r Act.
    A  Multimedia  Health Assessment  for  Manganese had been  drafted  1n  1979  to
 evaluate the health  effects of  manganese.   The original  document has  since
 been modified  1n  scope  and emphasis and updated.  This HAD 1s designed  to  be
 used by OAQPS for  decision making.
     In  the development  of this  assessment  document,  the  scientific  litera-
 ture has been  Inventoried, key studies  have been evaluated and summaries arid
 conclusions  have   been  directed  at  qualitatively   Identifying   the   toxic
 effects  of manganese.   Observed effect  levels and  dose-response relation-
 ships  are   discussed  where  appropriate  1n  order   to  Identify  the critical
 effect  and to  place adverse  health reponses  In  perspective with observed
 environmental levels.
                                     111
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                 LIST OF AUTHORS,  CONTRIBUTORS AND REVIEWERS
Dr. D1nko Kello (author)
Institute for Medical Research
Zagreb, Yugoslavia

Mr. Randall J.F. Bruins (author)
ECAO-C1n, U.S. Environmental Protection Agency

Dr. Linda S. Erdrelch (author, document manager)
ECAO-C1n, U.S. Environmental Protection Agency

Dr. Jerry F. Stara (document manager)
ECAO-C1n, U.S. Environmental Protection Agency

Dr. Steven J. Bosch
Syracuse Research Corporation
Syracuse, NY

Dr. Tom Clarkson
University of Rochester
Rochester, NY

Dr. Herb Cornish
School of Public Health
University of Michigan
Ann Arbor, MI

Dr. Michael Dourson, ECAO-C1n
U.S. Environmental Protection Agency

Dr. D. Anthony Gray
Syracuse Research Corporation
Syracuse, NY

Dr. Paul Hammond
University of Cincinnati
Cincinnati, OH

Dr. Rolf Hartung
School of Public Health
University of Michigan
Ann Arbor, MI

Dr. Bernard Haberman
Carcinogen Assessment Group
U.S. Environmental Protection Agency
Washington, DC

Dr. T.J. Knelp
NYU Medical Center
Tuxedo,  NY
                                       1v
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Or. James La1
Burke Rehabilitation Center
Dementia Research
White Plains, NY

Mr. C.A. Hall
Ethyl Corporation
Ferndale, MI

Dr. Fred Moore
Elklns Metal Company
Marietta, OH

Dr. Debdas Mukerjee, ECAO-C1n
U.S. Environmental Protection Agency

Dr. Nancy Pate
U.S. Environmental Protection Agency
Office of A1r Quality Planning and Standards
Research Triangle Park, NC

Dr. W. Bruce Pelrano, ECAO-C1n
U.S. Environmental Protection Agency

Dr. wnilam Pepelko, ECAO-C1n
U.S. Environmental Protection Agency

Dr. Mangus Plscator
School of Public Health
University of Pittsburgh
Pittsburgh, PA

Dr. Ivan Rabar
Institute for Medical Research
Zagreb, Yugoslavia

Dr. Marco Sarlc
Institute for Medical Research
Zagreb, Yugoslavia

Dr. Samuel Shlbko
Contaminants and Nat. Toxic. Evaluation Branch
Division of Toxicology, Food and Drug Administration
Washington, DC

Dr. Ellen Sllbergeld
Environmental Defense Fund
Washington, DC

Dr. Melvyn Tochman
John Hopkins Hospital
Baltimore, MD
1794A                                                                5/11/83

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Dr. Otto Weber
Institute for Medical Research
Zagreb, Yugoslavia

Or. David Well
Environmental Criteria and Assessment Office
U.S. Environmental Protection Agency
Research Triangle Park, NC

Dr. James WUhey
Food Directorate, Bureau of Chemical Safety
Ottawa, Ontario
Special Acknowledgement:    Technical Services and Support Staff, ECAO-C1n
                            U.S. Environmental Protection Agency
                                      v1


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                              TABLE OF CONTENTS
                                                                        Page
 1.  INTRODUCTION	    1-1

 2.  SUMMARY AND CONCLUSIONS	    2-1

     2.1.  SUMMARY OF EXPOSURE	    2-1
     2.2.  SUMMARY OF BIOLOGICAL ROLE AND HEALTH EFFECTS 	    2-6

           2.2.1.  Biological Role 	    2-6
           2.2.2.  Toxldty	    2-7

     2.3.  CONCLUSIONS	    2-11

 3.  GENERAL PROPERTIES AND BACKGROUND INFORMATION 	    3-1

     3.1.  PHYSICAL AND CHEMICAL PROPERTIES	    3-1

           3.1.1.  Manganese Compounds 	    3-4

     3.2.  SAMPLING AND ANALYTICAL METHODS 	    3-8

           3.2.1.  Sampling	    3-9
           3.2.2.  Sample Preparation	    3-14
           3.?.3.  Analysis	    3-H

     3.3.  PRODUCTION AND USE	    3-17

           3.3.1.  Production	    3-17
           3.3.2.  Use	    3-24

     3.4.  SOURCES OF MANGANESE IN THE ENVIRONMENT	    3-27

           3.4.1.  Crustal Materials and Soils 	    3-27
           3.4.2.  Industrial and Combustion Processes  	    3-30
           3.4.3.  Relative Importance of Manganese Sources at
                   Several Locations as Determined by Mass Balance
                   and Enrichment Models 	    3-38

     3.5.  ENVIRONMENTAL FATE AND TRANSPORT PROCESSES	    3-48

           3.5.1.  Principal Cycling Pathways and Compartments  .  .  .    3-48
           3.5.2.  Atmospheric Fate and Transport	    3-50
           3.5.3.  Fate and Transport 1n Water and Soil	    3-54

     3.6.  ENVIRONMENTAL LEVELS AND EXPOSURE 	    3-60

           3.6.1.  A1r	    3-60
           3.6.2.  Water 	    3-75
           3.6.3.  Food	    3-79
           3.6.4.  Human Exposure	    3-81
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     3.7.   SUMMARY  OF  GENERAL  PROPERTIES  AND  BACKGROUND  INFORMATION.
                                                                       Page
  3-89
           3.7.1.   Chemical  and  Physical  Properties	     3-89
           3.7.2.   Sampling  and  Analysis  	     3-89
           3.7.3.   Production and  Use	     3-91
           3.7.4.   Sources of Manganese  1n  the  Environment  	     3-92
           3.7.5.   Environmental Fate  and Transport  Processes.  .  .  .     3-94
           3.7.6.   Environmental Levels  and  Exposure 	     3-95

 4.   BIOLOGICAL  ROLE  AND  PHARMACOKINETICS	     4-1

     4.1.   BIOLOGICAL ROLE OF MANGANESE	     4-1

           4.1.1.   Biochemical Role	     4-1
           4.1.2.   Manganese Deficiency	     4-1
           4.1.3.   Manganese Requirements	     4-2
           4.1.4.   Summary  	     4-2


     4.2.   COMPOUND DISPOSITION  AND  RELEVANT PHARMACOKINETICS.  ...     4-3

           4.2.1.   Absorption	     4-3
           4.2.2.   Distribution  and  Normal  Tissue  Levels  	     1-6
           4.2.3.   Excretion	     4  10
           4.2.4.   Biological Half-time	     4-12
           4.2.5.   Homeostasls  	     4-13
           4.2.6.   Summary  	     4-20

     4.3.   SYNERGISTIC/ANTAGONISTIC  FACTORS	     4-21

           4.3.1.   Interaction with  Metals  	     4-21
           4.3.2.   Effect of Age	     4-23
           4.3.3.   Summary  	     4-26

 5.   TOXIC EFFECTS AFTER  ACUTE EXPOSURE	     5-1

     5.1.   ANIMAL  STUDIES	     5-1
     5.2.   HUMAN STUDIES	     5-4
     5.3.   SUMMARY	     5-5

 6.   TOXIC EFFECTS AFTER  CHRONIC EXPOSURE	     6-1

     6.1.   NEUROTOXIC EFFECTS — HUMAN STUDIES  	     6-1

           6.1.1.   Case Reports  and  Ep1dem1olog1c  Studies	     6-3
           6.1.2.   Pathology of  Manganese Poisoning	     6-14
           6.1.3.   Summary  	     6-14
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                                                                        Page
     6.2.   NEUROTOXIC EFFECTS — ANIMAL STUDIES ...........     6-15

           6.2.1.   Mechanism of Manganese Neurotox1c1ty .......     6-23
           6.2.2.   Altered Neurotransmltter  Metabolism .......     6-25
           6.2.3.   Summary .....................     6-35

     6.3.   LUNG EFFECTS .......................     6-36

           6.3.1.   Human Studies ..................     6-36
           6.3.2.   Animal Studies ..................     6-46

     6.4.   REPRODUCTIVE EFFECTS ...................     6-58

           6.4.1.   Human Studies ..................     6-58
           6.4.2.   Animal Studies ..................     6-58
           6.4.3.   Summary .....................     6-61

     6.5.   HEMATOLOGIC EFFECTS ...................     6-62

           6.5.1.   Human Studies ..................     6-62
           6.5.2.   Animal Studies ..................     6-63
           6.5.3.   Summary .....................     6-G4

     6.6.   CAROJOVASCUIAR SYSTFM EFFECTS ..............     6 65

           6.6.1.   Human Studies ..................     6-65
           6.6.2.   Animal Studies ..................     6-66
           6.6.3.   Summary .....................     6-66

     6.7.   BIOCHEMICAL EFFECTS ...................     6-66

           6.7.1.   Human Studies ..................     6-66
           6.7.2.   Animal Studies ..................     6-67
           6.7.3.   Summary .....................     6-68

     6.8.   DIGESTIVE SYSTEM EFFECTS .................     6-68

           6.8.1.   Gastrointestinal Tract Effects ..........     6-68
           6.8.2.   Liver Effects ..................     6-69
           6.8.3.   Summary ........... ..........     6-71

     CARCINOGENICITY ........................     7-1

     7.1.   ANIMAL  STUDIES ......................     7-1
     7.2.   HUMAN STUDIES ......................     7-7
     7.3.   SUMMARY .........................     7-10
                                      1x
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                                                                       Page


 8.   MUTAGENICITY AND  TERATOGENICITY  	    8-1

     8.1.   MUTAGENICITY	    8-1

           8.1.1.  Tests  for  Gene  Mutations	    8-1
           8.1.2.  Tests  for  Chromosomal  Damage	    8-1
           8.1.3.  Tests  for  Other Genetic  Damage	    8-1

     8.2.   TERATOGENICITY	    8-3
     8.3.   SUMMARY	    8-4

 9.   EFFECTS OF  CONCERN AND HEALTH HAZARD EVALUATION  	    9-1

     9.1.   EXISTING GUIDELINES,  RECOMMENDATIONS  AND STANDARDS.  ...    9-1

           9.1.1.  A1r	    9-1
           9.1.2.  Water  	    9-1

     9.2.   SUMMARY OF  TOXICITY	    9-2
     9.3.   SPECIAL GROUPS AT RISK	    9-5
     9.4.   EFFECTS OF  MAJOR CONCERN AND EXPOSURE/RESPONSE  INFORMATION  9-7

           9.4.1.  Effects of Major Concern	    9-7
           9.4.2.  Exposure/Response  Information 	    9-7

     9.5.   HEALTH HAZARD EVALUATION	    9-11

           9.5.1.  Critical Effect and Effect Levels  	    9-11

10.   REFERENCES	    10-1

APPENDIX:  ESTIMATING HUMAN EQUIVALENT INTAKE LEVELS FROM ANIMAL
          STUDIES	    A-l
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                                LIST OF TABLES


 No.                               Title                                Page

3-1      Physical Properties of Manganese	    3-2

3-2      Normal Oxidation Potentials of Manganese Couples	    3-3

3-3      Physical Properties of Some Manganese Compounds 	    3-5

3-4      Relative Sensitivity of Some Important Analytical Techniques
         for Manganese	    3_18

3-5      Estimated United States Production, Capacity and Use of
         Selected Manganese Compounds	    3-21

3-6      Manganese Supply-Demand Relationships, 1969-1979	    3-22

3-7      Net United States Production of Ferromanganse and
         SHIcomanganese	    3-23

3-8      Commercial Forms of Manganese  	    3-25

3-9      Manganese Content of Selected Minerals	    3-29

3-10     Sources and Estimated Atmospheric Emissions of Manganese
         1n 1968	! . . .  .    3-31

3-11     Estimated Manganese Emissions from Controlled Submerged-Arc
         Furnaces Producing Manganese Alloys 	    3-34

3-12     Manganese Concentrations of Coal, Fuel 011, Crude 011,
         Gasoline, Fuel Additives and Motor 011	    3-35

3-13     Manganese Content 1n Coal Ash	    3-36

3-14     Manganese Concentration 1n Fine (<2.0 um) and Coarse
         (2.0-20 urn) Particle Fractions of Aerosols from Several
         Sources 1n the Portland Aerosol Characterization Study. .  .    3-40

3-15     Manganese Concentrations 1n Aerosols from Various Sources,
         and Estimated Percent Contribution of Each Source to Observed
         Ambient Manganese and Total Aerosol Mass at Two Sites . .  .    3-42

3-16     Manganese Concentrations In Aerosols from Various Sources,
         and Estimated Percent Contribution of Each Source to
         Observed Ambient Mn and Total  Aerosol Mass, Based on Target
         Transformation Factor Analysis	    3-43

3-17     Number of National  A1r Surveillance Network Stations within
         Selected Annual Average Manganese A1r Concentration
         Intervals,  1957-1969	    3_61
                                      xl
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                            LIST OF  TABLES (cont.)


 No.                               TUIe                                Page

3-18     National  A1r Surveillance Network Stations with Annual
         Average Manganese A1r Concentrations Greater Than
         0.5 ug/m3 ............... .   .........     3-62
3-19     Average Manganese Concentration 1n Ambient A1r and Total
         Suspended Partlculates (TSP) 1n Urban and Nonurban NASN
         Sites, 1966-1967 ......................    3-64

3-20     Urban NASN Sites, 1970-1982: National Cumulative Frequency
         Distributions of Quarterly Values for Manganese Concentration  3-66

3-21     Nonurban NASN Sites,  1970-1982: National Cumulative Frequency
         Distributions of Quarterly Values for Manganese Concentration  3-67

3-22     Manganese Concentrations 1n A1r, Kanawha Valley Area,
         West Virginia .......................    3-68

3-23     Ambient A1r Sampling Data for Total Suspended Partlculates
         and Manganese (1n ng/m3) 1n  the Marietta, OH-Parkersburg, WV
         Vicinity, 1965-1966 and 1982 1933 .............    3 70

3-?4     Concpnt rat Ions of Trace Metals in A1r Measured at Three
         Locations In New York City .................    3-71

3-25     Selected Dlchotomous Sampler Data on Manganese and Particle
         Mass from 22 U.S. Cities In 1980 ..............    3-74

3-26     Concentration of Manganese 1n Various Lake and River Waters    3-76

3-27     Mean Concentrations of Dissolved Manganese by Drainage Basin   3-77

3-28     Dissolved and Suspended Manganese 1n Five U.S. Rivers  .  .  .    3-78

3-29     Cumulative Frequency Distribution of Manganese Concentration
         1n Tap Waters Sampled 1n the HANES I Augmentation Survey of
         Adults ...........................    3-80

3-30     Estimates of Human Inhalation Exp]osure to Manganese 1n
         Ambient A1r  ........................    3-85

3-31     Dietary Intake of Manganese  1n the U.S ...........    3-86

3-32     Intake of Manganese from Food by Children .........    3-88

4-1      Manganese 1n Human Tissues .........  .  .......    4-7

4-2      Concentrations of Manganese  1n Liver, Kidney and Brain.  .  .    4-16
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                            LIST OF TABLES (cont.)


 No.                               TUIe                                Page

5-1      Acute LOgQ Values for Manganese Compounds .........    5-2

5-2      Influence of Age on Manganese ToxIcHy 1n Rats: LD5Q Values
         8 Days after a Single Oral Administration of MnCl2 .....    5-3

6-1      Studies of Manganlsm 1n Humans and Exposure-Response
         Relationship ........................    6-5

6-2      Frequency of Abnormal Neurological Findings ........    6-8

6-3      Ferroalloy Workers with Neurological Signs by Level  of
         Exposure to Manganese ...................    6-12

6-4      Neurotoxlc Effects of Manganese 1n Experimental Animals .  .    6-17

6-5      Neurological Signs Induced by Manganese In Monkeys .....    6-21

6-6      Prevalence of Chronic Bronchitis In Groups of Workers
         According to Smoking Status ................    6-41

6-7      Cumulative Incidence of Acute Respiratory Diseases During
         thp 3-Year Period .....................    f> **?

6-8      Summary of Human Studies of Respiratory Effects at Various
         Levels of Exposure to Manganese ..............    6-47

6-9      Respiratory Effects with Manganese Exposure: Intratracheal ,
         Intraperltoneal and High Dose Inhalation Exposures .....    6-48

6-10     Respiratory Effects with Manganese Exposure: Inhalation
         Exposures at Low Doses ...................    6-54

6-11     Pulmonary Physiology Data for Male and Female Monkeys After
         Nine Months of Exposure ..................    6-56

7-1      Pulmonary Tumors 1n Strain A Mice Treated with Manganese
         Sulfate ..........................    7-2

7-2      Carc1nogen1c1ty of Manganese Powder, Manganese Dioxide and
         Manganese Acetylacetonate 1n F344 Rats and Swiss Albino
         Mice ............................    7-4

7-3      Induction of Sarcomas 1n Rats by the Intramuscular
         Injection of Manganese Dust ................    7-8

9-1      Studies of Manganese Inhalation 1n Animals — Summary of
         Effect Levels .......................    9-9

A-l      Exposure Effect Information for Health Hazard Evaluation:
         Human Equivalent Exposure Levels Estimated from Animal Data    A-3
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                               LIST OF FIGURES


 No.                               TUIe                                Page

3-1      The Global Cycles of Manganese	    3-49

3-2      Concentration Factors for Manganese 1n Hudson River ....    3-59

6-1      Schematic Representation of the Mechanisms of Actions of
         Manganese on the Central Dopam1nerg1c System	    6-27
                                      x1 v
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                   6.  TOXIC EFFECTS AFTER CHRONIC EXPOSURE
6.1.   NEUROTOXIC EFFECTS - HUMAN STUDIES
    The  effect  of manganese on  the CNS 1s  a  serious adverse effect  and 1s
often known  as  manganlsm.   According to Voss  (1939)  there were  152 cases of
manganlsm described  1n  the literature prior to  1935.   By  1943,  Falrhall and
Neal  (1943)  found 353  cases  of manganese  poisoning.   Subsequently,  reports
of at least 200 additional cases of manganlsm have been published.
    The  signs  and  symptoms of  chronic manganese  poisoning  have been  de-
scribed  1n detail several  times  (FUnn  et  al.,  1940;  Ansola et al., 1944a,b;
Penalver, 1955;  Rodler,  1955;  Schuler  et  al.,  1957;  Chandra  et  al.,  1974).
This  poisoning  can  result  from  exposure  to manganese  aerosols after  only a
few  months  (Ansola  et  al., 1944b),  although  H usually  results  from expo-
sures of 2-3 years or  longer.    It has  been suggested that damage 1s revers-
ible  1f  the patient  1s  removed from  exposure  at an  early  stage.   On the
other hand,  Barbeau et  al.  (1976)  observed that  signs and  symptoms persisted
and even worsened several  months after  exposure  had  ceased.   This finding 1s
corroborated by  Cotzlas  et al.  (1968) who reported  that  the  presence of
elevated tissue manganese  concentrations was not  necessary for the confirma-
tion  of  poisoning.    A  person  who  has  recovered  from manganese  poisoning
seems to be prone to contracting the Illness again.
    The  classical clinical  picture  of  the disease  had  been divided  Into
three phases  on  the  basis of  reports  from the  United States,  Morocco and
Cuba by Cotzlas (1962):
1.  Prodromal   Phase.    The  disease   begins   Insidiously  with   anorexia,
    asthenia,  and   occasionally  psychotic  behavior.    Severe   somnolence
    followed by Insomnia  1s often  found early 1n the  disease.  Headache and
    leucopenla   may   further  confuse  the  differential   diagnosis  between
    manganlsm and viral encephalitis.

1803A                               6-1                               5/06/83

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2.   Onset  of  the  Extrapyramldal   Disease.    Clumsy   articulation   overlaps
    encephalHIc manifestations  1n  the prodromal  phase,  often resulting  1n
    muteness.  A mask-like face  and  general  clumsiness with loss of  skilled
    movement are characteristic.
3.   Established Manganlsm.  Fully developed manganlsm  causes  severe  rigidity
    with  the  extremities  showing  the  "cogwheel"  phenomenon.   Tremors  may
    occur which  become exaggerated  by emotion,  stress,  fatigue or  trauma.
    Indifference  occurs,   Interrupted  by  spasmodic  laughter  or  by  crying
    spells.    Similarly,   an  autonomlc  disturbance manifested  by  excessive
    salivation and sweating may become apparent.
    Symptoms and  signs  of chronic manganese  poisoning have often  been  com-
pared  to  Parkinson's  disease,  but  certain  differences   should  be  noted.
Tremor,  for  example,  1s  frequently  an Intention  tremor  1n  manganlsm and not
the resting  tremor  that  1s typical  for Parklnsonlsm  (Klawans  et  al., 1970).
Barbeau  et  al.  (1976)  provide a revised description  suggesting  that chronic
manganese poisoning  Is  a  better model  of  dystonla than of Parkinson's  dis-
ease.   These authors  base such  an  assumption on  the  observations  that  some
form  of  dystonla,  defined as a  postural Instability  of  complementary muscle
groups,  Is   an  almost  obligatory feature  of  the manganlsm.   They  think 1t
probable  that  the minor  manifestations of dystonla and  torticollis  were not
properly  described 1n  many  papers.   They  also  point  out that  the tremor
observed  1n  some  of  the  patients with manganese poisoning  Is quite different
from  that  seen 1n Parkinson's disease.   In their opinion 1t has much more of
an  attHudlnal  or flapping quality resembling  that  seen 1n Wilson's disease
or,  for  that   matter,  1n  dystonla   musculorum  deformans.   Barbeau  et al.
(1976)  present a  further argument  to separate  chronic  manganese poisoning
from  Parklnsonlsm based  on  the pathological  findings:   the  classical  flnd-


1803A                               6-2                               5/06/83

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1ngs 1n Parkinson's disease are deplgmentatlon and  loss of  cells  1n  the  sub-
stantla nlgra, locus caerulesus, and dorsal nucleus of  the  vagus  with  Uttle
damage to the stMatum or palUdum.  In  chronic  manganese  poisoning  there  1s
no  appreciable  destruction  of  the  substantla nlgra;  the  lesions are  found
mainly within the stMatum and palUdum.
    On  the  basis  of  the  clinical  similarity  to  Park1nson1sm,  established
manganlsm has shown some  Improvement  after treatment with  levadopa  (Mena  et
al., 1970;  Rosenstock  et  al.,  1971),  confirming the depletion of the  dopa-
mlnerglc system (Cotzlas  et  al., 1976).
    A more  specific  description of the  earlier  stages of  this disorder  has
appeared 1n  conjunction  with a report  of  cases  1n the United  States   {Cook
et  al.,  1974).   Symptoms  were consistent with the  literature  except for  the
absence  of  "manganese psychosis."   The most  characteristic  signs  were  the
various  gait  disorders.   Six cases showed  similarity  1n  the  earliest  symp-
toms:   somnolence,  1ncoord1nat1on,  speech  disorder,   gait  difficulty,  and
Imbalance.   Postural tremor and tremors  at  rest  were  seen  1n  four of the six
cases.   In no case was this  tremor  the only symptom and all four  had slurred
speech, asthenia and somnolence.
6.1.1.   Case Reports and Ep1dem1olog1c Studies.   Reports  of  cases  of  man-
ganlsm and  the  associated clinical  descriptions have  established that  expo-
sure to manganese can cause  chronic manganese poisoning 1n  some Individuals.
In  order to establish levels  of exposure at which effects  do  not  occur  1t  1s
necessary to have data with  clearly described levels  of exposures (Including
specific compound and particle  size).   The number  and  selection  of  Individ-
uals  exposed  and  studied should  be  clearly defined  Including data on  the
duration of  exposure.   Although there has  been  a  good deal of occupational
exposure to  manganese,  this  type  of   dose/response  data  Is not  available.


1803A                               6-3                              5/06/83

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There are,  however,  many  reports  of  cases of  manganlsm Including a  few  In
which an  Identified  exposed group has  been  examined for early  signs  of  the
disease.  The  studies  which have been reviewed with  the goal  of Identifying
the  no-observed-effect  level   (NOEL)  are  discussed.   However,  the  cross-
sectional  approach  of  most  of  the  studies  Introduces  selection  biases,
Including the  concern  that disabled  Individuals may  have been  lost from the
work force  and excluded from the studies.  Despite  these  limitations, there
are  human studies  which, taken together, define a  range of  lowest-observed-
effect  levels  (LOEL).
     Manganlsm  has  been  described 1n  workers  1n  ore  crushing  and  packing
mills,  1n  the ferroalloy  production,  In the use of  manganese  alloys  1n the
steel Industry,  1n  the manufacture of  dry cell  batteries, and 1n welding rod
manufacture.   Exposure  typically  Involved  manganese oxides  but Information
on  manganese  concentrations and the  occurrence  of  other chemicals at working
places  was  usually  limited.   Few  studies dealt with the particle size dis-
tribution of  manganese aerosols.
     Most  of  the described cases of  manganlsm  occurred  1n  manganese mines.
The reported  poisonings were  among  Huelva miners  1n Spain  (Dantln Gallego,
1935,  1944),  S1na1  miners (Nazlf,  1936;  Scander  and  Sallam,  1936), miners
from Glessen  1n Germany (Buttner  and Lenz,  1937),  Moroccan miners  (Baader,
1939;   Rodler  and  Rodler,  1949),  Chilean miners  (Ansola et  al.,  1944a,b),
Cuban  miners  (Garcia  Avlla and  Penalver,  1953),  Suceova miners  1n  Rumania
 (Wassermann  et  al.,   1954),   Mexican  miners  (Roldan,  1956),  USSR miners
 (Khazan et al.,  1956;  Khavtasl,  1958),  Japanese  miners  (Suzuki  et   al.,
 1960),  and  Indian  miners (Balanl  et  al., 1967).
     Table  6-1 contains  a summary of  those  studies  with corresponding  expo-
 sure data  and a  description   or  response frequency  for  CNS  Involvement  1n


 1803A                               6-4                              5/06/83

-------
TABLE 6-1
o
VjO
Type of Exposure
Ore crushing mill/dust
Manganese mine
Manganese mine; dusts
Manganese mine
Industrial plants
Dry-cell battery
Industry; dusts
i
vn Ferromanganese produc-
tion and processing
ferromanganese In-
dustry
Ferromanganese In-
dustry: electric
furnace workers
en
O
o> Ferromanganese plant,
^5 dust and fumes
Chemical
(particle size)
oxides, mostly
Hn02 (NR)
NR
NR (90% <5 u)
oxides (NR)
NR
65% Mn02 (NR)
ferromanganese,
small amounts
of MnO, Hn304
(95% <5 u)
and/or
100% Mn oxides,
mainly Mn304
(<2 w)
NR
(0.5-6 VL;
mostly 4.5)
NR (<1.5 u)
NR
Exposure Level
(mg Mn/nr)
10-30
30-180
62.5-250
250-450
1.5-16b
<5
5-30
6.8-42.2b
2.1-12.9
and/or
0.12-13.3
0.06-4.9
3.2-8.6
0.30-20.44
Duration of Exposure
3.3 yr average
178 days
~1 mo to 10 yr
8.2 yr average
(9 mo to 16 yr)
NR
7.5 yr average
{1-16 yr, cases)
8-26 yr 1n five cases
12 yr
(12 hr/day)
8.5+6.8 yr
27% <4 yr
9.8% >20 yr
Number Affected/
Number Studied
0/9
11/25
12/72
NR
15/83
0/38
7/117
8/36
5/71
26/160
40/100
62/369
Pathological Reference
Findings8
none Fllnn et al., 1941C
44% manganlsm
manganlsm Ansola et al., 1944a,b
150 cases manganlsm Rodler, 1955
manganlsm Schuler et al., 1957
none Tanaka and Lleben, 1969
6% manganlsm
22.2% manganlsm Emara et al., 1971
psychosis
7% manganlsm Smyth et al.. 1973
30% subjective symp- Suzuki et al., 1973a
toms; 2% "health dis-
orders due to manga-
nlsm"; symptoms In-
creased with number of
years of employment
40% subjective symp- Suzuki et al., 1973b
toms; 8-10% single
neurological signs,
e.g. , tremor of
fingers
16.8% slight neuro- Sarlc et al., 1977C
logical signs, e.g..
                                   tremor at rest, patho-
                                   logical reflexes

-------
                                                                          TABLE  6-1  (cont.)
CO
Q 	 , 	 _^___
Oi
•** Type of Exposure
Control I electrode
plant


Control II aluminum
rolling rail!
(ambient levels)
Welding fumes





Chemical Exposure Level Duration of Exposure
(particle size) (mg Mn/m3)
0.002-0.030 NR
(emissions from
ferromanganese
plant)
<0.07 ug/m3 NR


NR 0.44-0.99d 20.2 (mean yr) (10-31)


0.5-0.8d 21.9 (mean yr) (2-32)
0.88-2.6d 14.1 (mean yr) (6-27)

Number Affected/
Number Studied
"n/190



0/204


5/20


10/20
9/20

Pathological
Findings3
5.8X neurological
findings


none


25X slight neurologi-
cal signs (brisk deep
reflexes)
SOX
45X

Reference
Sarlc et al., 1977



Sarlc et al., 1977


Chandra et al.. 1981





    Percentage 1s given If sample has been selected such that the rate can be considered an estimate of prevalence
    bRange of averages for different areas or workstations sampled
    cSee also Tables 6-2 and 6-3
    dln workers breathing zone
    NR = Not reported
tn
X.
o
oo
to

-------
workers  occupatlonally  exposed  to  manganese  by  Inhalation.   These  studies

are presented  1n  chronological order.   The  earlier ones  1n  particular  have

several  limitations  due  1n part  to  the  fact  that  they  were  designed  to

obtain  clinical  Information  rather   than   Incidence  or  prevalence  rates.


Generally  the  exposure  data covers a  broad  range and does  not Include  par-


ticle  size or  chemical  characterization.   In some cases  exposures  change


over time  (e.g., Fllnn et  al.,  1941;  Smyth  et al.,  1973).  The selection and


composition of  the  exposed group may  not  be adequately  described  or  may  be


based  on high  exposure.   None  of  these studies  employs a  standard  cohort


design.   Duration  of  exposure  1s  sometimes  presented  only  for  diagnosed


cases, and  the  endpolnts  differ among studies.  Percentages  reported  1n the


table  reflect  prevalence   of   the  pathological  findings  1n  the  group  as


described.  While the  use  of this Information  for  obtaining a dose-response


association Is  limited  quantitatively,  1t does  show evidence  of  effects  1n

humans and can be used to define a range of LOELs.


    FUnn  et  al.  (1941) examined  34  manganese exposed  workers representing


all of the  exposed Individuals  from  the  same ore  crushing mill.  The authors


described  the  23 workers  without chronic manganese  poisoning as  exposed but

not affected.   However,  Table  6-2 shows that these workers  had  some  neuro-


logical  findings which might  be Indicative of  early manganlsm.  The average

exposure for  those affected was 5.3 years and  for  the exposed workers unaf-


fected was  2.4 years.   No case  of  manganlsm was  detected  1n  nine  workers

                                                             o
exposed  to  average  manganese  concentrations  of  10-30  mg/m   1n  two  manga-

nese ore crushing mills  (FUnn et al.,  1940).  The lowest average manganese

                                                            o
concentration at which  the  disease  was found  was  30 mg/m  .   However,  only


two of  these  nine  men were  exposed  for  more than  3 years.   Although the

entire exposed  group was  examined, the  numbers are small  and exposures too

short to define 16-30 mg/m  as a NOEL.



1803A                               6-7                              5/06/83

-------
CO
o
to
3»



C"
CO







in
o
CT>
v>
CO
OS


Total examined
Tremor of tongue
Gait disturbances
Speech disturbances
Tremor of extremities
Muscular weakness
Intention tremor of hands
Abnormal reflexes
Masked fades
Sensitive achllles tendon
Abnormal handwriting
Spasm of extremities
Lateral nystagmus, slight
Abnormal psyche
Frequency

Affected

91
90b
73
55
55
45
45
45
36
27
18
18
18
1 HDLI
of Abnormal
Percentage
Nonaffected

35
0
0
22
0
17
35
0
4
0
0
17
4
: v-c
Neurological

Nonexposed

19
0
0
0
0
0
31
0
0
0
0
0
0
Findings3

Affected
11
10
9b
8
6
6
5
5
5
4
3
2
2
2

Number of Cases
Nonaffected
23
8
0
0
5
0
4
8
0
1
0
0
4
1


Nonexposed
16
3
0
0
0
0
0
5
0
0
0
0
0
0
 Source:   Fllnn  et  al.,  1941
'Excluding Case  No.  64 who  was  too weak  to walk normally due  to  a  previous  Illness

-------
    In  1955,  Rodler  reported 150  cases  of  manganlsm  from three  Moroccan
mines.  Underground workers  engaged  1n drilling blast holes  ran  a high risk
of developing manganese  poisoning;  132  of  150 cases occurred  among  workers
using the  drills  and  the other cases  were  laborers  who  worked  nearby.   Con-
centrations  of  manganese  were usually  very  high  In the  mines  from  which
cases of manganlsm were  reported.  The manganese  concentration  1n the air 1n
                                                                            3
the  Immediate  vicinity  of  rock drilling  1n Moroccan mines  was  =450  mg/m
                            3
1n  one  mine  and =250 mg/m   1n  another.   Analyses of  the ores  Indicated
that  toxldty  was  not strictly related to manganese  content; most of  the
cases of  manganlsm  resulted  from exposure  to  an  ore from one  mine  that  was
less  oxidized  than  the ores  from  the  other  mines.   In  two  reports  from
Chilean mines (Ansola  et al., 1944a,b;  Schuler et  al.,  1957) the concentra-
                                                         3
tlons of  manganese  In the  air  varied from 62.5-250  mg/m  and  from  an  aver-
                    3
age  of  1.5-16  mg/m ,  respectively.   Schuler  et al.  (1957)  observed  that
the  Introduction  of pneumatic drilling  and the associated  Increase  1n dust
led  to  outbreaks  of manganlsm.  The  Investigators did not examine all of the
workers and  stated that  their study  was  not designed  to  provide Incidence.
data.   The total  number examined was =83  and  the  procedure  for selecting
them was not described.  Therefore, prevalence rate was not applicable.
    Emara  et al.  (1971)  studied 36 workers exposed to manganese dioxide dust
1n  a factory  manufacturing  dry  batteries.   Average concentrations  ranged
                       3
from  6.8-42.2 mg Mn/m   1n  four  areas.  Eight workers  (22%)  exhibited  symp-
toms of manganlsm.  Concentrations at the  main working  areas of three of the
                                3
cases ranged  from  6.2-7.2  mg/m .   Cases  had  been working  1-16  years  prior
to diagnosis of chronic manganese poisoning.
    After  an Industrial  hygiene survey Identified certain plants 1n Pennsyl-
vania as having manganese  exposures  above  the  threshold  limit value (TLV) of
1803A                               6-9                              5/06/83

-------
      3
5 mg/m ,  Tanaka  and Lleben (1969)  selected  factories with and without  such
exposures, and examined workers  1n  the selected factories.  All  four  plants
processing manganese ore  or ferromanganese  had samples above  the  TLV  as  did
60% of chemical manufacturing plants.  Neurological  screening  of  117  workers
                                               3
from  the  factories where  exposures  >5  mg/m  had  been  detected  (81%  of
those exposed)  revealed  seven  cases  with  "definite  signs  and  symptoms  of
manganese poisoning."  This study does not  support  a lack of  effect at expo-
              3
sures <5  mg/m  due  to  lack of  standardized  examination  procedures,  expla-
nation of selection patterns, details  on Industrial  exposures,  duration  of
exposure, and  the  small,  unrepresentative sample 1n  the  low  exposure group.
The only  exposure levels presented were for the two case histories described.
    Smyth et al. (1973) performed repeated  sampling and analysis  of the man-
ganese concentration around 15 work  positions  1n  a ferromanganese alloy pro-
cessing  plant.   They selected  71 employees  for study who were exposed dally
1n areas  Involving  these  work  positions.   Another  group of 71 unexposed male
employees  matched  by age  and  length of plant  service were selected  as con-
trols.   The weighted average concentrations  for manganese 1n air  ranged from
               o                                      3
0.12-13.3 mg/m   for  fumes  and from  2.1-12.9  mg/m   for manganese  dust.
Five  exposed  Individuals  and  no controls  had  signs suggestive of early man-
ganlsm.   Three of  these   cases  had  several  classical signs  such  as masked
 fades,  but  the  other  two had  only  loss of associated arm movements bilater-
ally.   The detailed exposures  by position  were  not  explained on  a  case by
 case  basis  and  therefore could  not  be associated  with  each   Individual.
 Exposure  duration   In  the five  cases  ranged from  8-26  years  although 1t 1s
 not  known  when  signs  of manganlsm first  appeared.   Thus,  all  cases were
 exposed  to the  high average  dust concentrations  which had been recorded 1n
                          3
 previous   years   (30 mg/m ).     The   authors  reported  a  poor   correlation
 between  manganese  exposure and manganese  excretion  In the urine.

 1803A                               6-10                              5/06/83

-------
                                                                         3
    Sarlc et  al.  (1977) compared  369  workers  exposed to 0.3-20 mg  Mn/m  at
a  ferroalloy  plant to  two  other groups;  190  workers at an  electrode  plant
                            3             3
exposed  to 0.002-0.03  mg/m   (2-30 p.g/m )  and  204  workers  at  an  aluml-
                                                                   3
num   rolling   mill   exposed    to   ambient  levels   <0.0001   mg/m    (<0.10
    3
v.g/m  )•   Neurological  examinations  were  given  to  95%  of  all  workers.
Prevalence of neurological signs was 17% 1n  workers  1n the ferroalloy plant,
compared  to  6%  and  0%  of  workers  1n  the  electrode  and  aluminum  plant,
respectively.   The  most prevalent  symptom,  tremor  at rest,  cannot  be  defi-
nitely attributed  to  exposure  to manganese.   There was  no  apparent  associa-
tion  of  neurological  symptoms  with smoking  habit.   The  ferroalloy workers
were  further  categorized  Into  three groups by  mean  manganese concentrations
                              33                   3
at  working  places:   <5  mg/m  ,  9-11  mg/m ,   and  16-20   mg/m .    In  addi-
tion  to  manganese  compounds,  carbon monoxide,  carbon dioxide  and  coal  dust
were  also  present.   Table  6-3  summarizes  neurological  signs observed  1n
these  groups.   These  data suggest  that  slight  neurological disturbances may
                           3
occur  at  exposures <5  mg/m  and seem  to  be  more prevalent  at higher  expo-
sures.  Although  analysis of the  effect by  duration  of  exposure  was Incom-
plete,  reducing  the  usefullness of this  study  for  obtaining dose-response
data,  1t does help  to establish a range  for a LOEL.
    Chandra  et  al.  (1981)  reported  on  three  groups  of  20 welders  each
                            3
exposed  to  levels <3  mg/m   compared  to 20  controls.   The welders  were
exposed  to manganese  released  from manganese-coated electrodes as  well as
from  materials  being  welded.    The  materials  being welded  were stated  to be
mainly  steel;  no  data  were  given  on  exposure to other metals.   The groups
came  from a  heavy  engineering  shop, a  railway workshop,   and  a  ship repair
shop.   Many workers  had been  employed  for  >10  years.    Means of  airborne
manganese  were  stated  to average  0.31, 0.57  and  1.75 mg/m  with  slightly
1803A                               6-11                             5/06/83

-------
00
o
CO
lABLt 0-J


* Ferroalloy Workers with Neurological Signs by Level of Exposure to Manganese3
Signs
Cogwheel phenomenon
Difficulty 1n Initiating voluntary movements
^ Pathological reflexes
"^ Tremor at rest
Pathological reflexes and tremor at rest
Cogwheel phenomenon and tremor at rest
Cogwheel phenomenon and pathological reflexes
Total
aAdapted from Sarlc et al., 1977
Mean Manganese Concentrations
0.301-4.933 9.480-11.062
(N = 268) (N = 17)
1 0
2 0
6 1
42 2
3 0
0 0
0 0
54 (20.1%) 3 (17.6%)

at Working Places (mg/m3)
16.347-20.442
(N = 18)
0
0
1
2
0
1
1
5 (27.8%)

Total
(N = 303)b







62 (16. 8X)

bTotal number examined was 369. The authors state 1n a footnote that "1n 66 workers with a mean manga-
nese exposure of 0.469-1.056 mg/m3 no neurological signs were found". It seems that these should be
<£ Included 1n the low exposure group 1n this table, 1n which case the prevalence of signs for this group is
S l&X.
oo
CO

-------
higher  ranges  1n  the  workers'  breathing  zone.    No  data  were  given  on
particle  size,  but H  can be  assumed  that both  fumes  and  small  particles
were  Inhaled.   Positive  neurological  signs were  reported to  occur  1n  the
form of brisk deep  reflexes of  the  arms  and legs and tremors  of the hand and
tongue 1n 25, 50  and  45%  1n  these three  groups respectively,  whereas none of
the controls  showed such  effects.   No  details of the  neurological  examina-
tion were  presented.   The mean exposure times  of  these  groups were  20,  21
and  14  years,   respectively.    No   statistical   analysis or   analysis  by
person-years of exposure was  presented.
    Sabnls et  al. (1966)  assessed  average  dally exposure  to manganese  1n a
ferromanganese alloy  factory  1n India.   The dally  average weighted exposures
               3
were  <2.3 mg/m   for  all  workers  1n  the  factory,  although  maximum  levels
                            3
were recorded  up  to  10 mg/m  .   The medical officer  of the factory reported
that he  had  observed  neither  acute  nor  chronic  cases of  manganese poisoning
among  the workers.  A 11st of  subjective  symptoms  of manganlsm was prepared
for  the  medical   officer  who  stated that  no worker  had  reported  such symp-
toms,  but  this  11st  was  not  Included  1n their  report.   This data cannot be
used  to  Identify  a  NOEL  because no clinical examinations  were  performed.
Other  reports  suggest that signs of manganlsm can  be Identified 1n Individ-
uals not experiencing symptoms  (e.g., Smyth  et al., 1973).
    Sabnls et al.  (1966)  relate 1n  their report  that manganese poisoning had
                                                                   3
occurred  1n  a nearby factory.   High  levels  of 8.8  and   8.4 mg/m  occurred
                                                   3
at  operations here compared  to  2.7 and  2.3  mg/m   recorded  1n  the  ferro-
manganese  alloy   factory  which  had  no  reports  of  poisoning.   Duration  of
exposure was  not  reported at  either factory.    The  authors concluded  that  6
    3
mg/m   (the  standard  In  effect  at that   time)   was  unsafe  and  that dally
                                  3
weighted exposures up to 2.3 mg/m  were  safe.
1803A                               6-13                             5/06/83

-------
    While the above studies do  not  show a clear dose-response relationship,
they  do  support  the  association  of  neurological  symptoms  and  signs  with
exposure to manganese.
6.1.2.   Pathology of Manganese Poisoning.  Pathologic  findings  observed  at
autopsy  have  ranged from  absence  of morphologic  changes,  through  specific
lesions of the basal ganglia  (extrapyramldal system), to generalized pathol-
ogy of  both  the  central  and  peripheral  nervous  systems  (Casamajor,   1913;
Ashlzawa, 1927; Canavan et  al., 1934;  Stadler,  1936;  Trendtel,  1936;   Voss,
1939,   1941;  Fllnn  et  al.,  1941;  Ardld  and  Torrente,   1949;  Parnltzke  and
Pfelffer, 1954; Bernhelmer  et  al.,  1973;  Barbeau  et al.,  1976).   The most
extensive degenerative changes have been found  1n  the corpus strlatum of  the
basal  ganglia (caudate nucleus, putamen and palUdum) and evidence  Indicates
that the palUdum  may be preferentially  damaged.
6.1.3.   Summary.   An  Important  effect  of chronic  exposure  to manganese  1s
the chronic  manganese  poisoning resulting  from  occupational  exposures  to
manganese dusts after  only a  few  months  of  exposure,  although other  cases
develop  only  after many  years.  Earlier  studies   report advanced  cases  of
manganlsm (1n various  miners),  but  more recent studies  report cases showing
neurological symptoms  and  a few signs  where  the exposure was at much  lower
concentrations.
    The human studies are not adequate  to  Identify a  dose-response  relation-
ship,   but  do  permit  the   Identification  of   the  LOEL.  The  full  clinical
picture of chronic  manganese  poisoning  Is reported less frequently  at  expo-
sure  levels  below 5  mg/m   (Sarlc  et al.,  1977;  Chandra  et  al.,   1981;
Tanaka  and  Lleben,  1969;  Sabnls  et  al.,  1966).   The  studies  reporting
effects at  the  levels  reported  by  Chandra et al.  (1981) and of  Sarlc  et  al.
(1977) describe effects which cannot  be definitely attributed  to manganese.


1803A                               6-14                             5/06/83

-------
Sarlc et al.  (1977)  report tremor at rest as  the major  effect  on  workers 1n
the  electrode   plant   exposed   to  2-30  ug/m    (0.002-0.03   mg/m ).    The
                                                            3
prevalence of  a few signs  In workers  exposed to 0.3-5  mg/m   (Sarlc  et al.,
                         3                                             3
1977)  and  0.4-2.6 mg/m   (Chandra  et   al.,   1981)  suggest 0.3  mg/m   (300
     3
ug/m )  as  a   LOEL.   The  data  available  for  Identifying  effect  levels
below this level  1s equivocal or  Inadequate.   This  1s further  complicated by
the  fact   that  good  biological   Indicators  of  manganese  exposure are  not
presently available.  Consequently,  studies  directed  toward clearly defining
the  dose-effect relationship will  undoubtedly  facilitate  a more  realistic
estimate of the risk to developing manganlsm.
     The broad  exposure  ranges,  the Incomplete descriptions of  chemical form
and  particle size  are Insufficient  to relate response to exposure  character-
istics.  The  exposure  data reported by Smyth  et  al.   (1973)  suggests that
ferromanganese  fumes  may  have  a  smaller  particle size than  the  dusts  and
                             ^
thus more resplrable particles.
     In  order  to  obtain definitive  dose  response  data, a  cohort  study  1s
needed,  Including documented clinical  examinations,  more  accurate exposure
characterization  as  well as  exposure  data  on Individuals.   All  members  of
the  cohort should be followed for  neurological  signs for at  least 20  years
and  numbers lost to follow up should be clearly reported.
6.2.   NEUROTOXIC EFFECTS - ANIMAL STUDIES
     The wide  range of  ep1dem1olog1cal   studies  Indicates that  the clinical
manifestations,  observed   morphological   lesions   and   biochemical  changes
described  1n   chronic  manganese  Intoxication  closely   resemble  those  that
occur  1n  other  extrapyramldal  disorders, notably  Park1nson1sm.    The  exact
mechanism of biochemical changes  1s still debated, as  1s the  role of manga-
nese 1n  the  extrapyramldal  syndrome  1n  exposed  workers  (Barbeau et  al.,
1803A                               6-15                             5/06/83

-------
1976; WHO,  1981).   Such  controversy  regarding the neurological component  of
chronic manganese  Intoxication  1n  exposed workers prompted  a  wide range  of
animal studies focused on the neurotoxlc  effects  of this  metal.
    Most of  the earlier neurologic  studies  1n  animals  utilized  the  paren-
teral or respiratory  route  of  administration.   Table 6-4 summarizes some  of
the  more  recent data on neurological  effects.   An  1n-depth analysis  of all
available animal  data suggests  no accurate  dose-response  relationship for
neurological effects of chronic manganese exposure can be assessed  since the
methodology and reported values vary  significantly among Investigators.  For
Instance, very  few of the  early  studies  reported brain levels of  manganese
(Pentschew  et  al.,  1963;   Neff et  al.,  1969;  Mustafa and  Chandra,   1971;
Bonllla  and D1ez-Ewald,  1974;  SHaramayya  et  al.,  1974).  In  some  of the
more  recent  studies  where  the brain  manganese  levels are  reported, the
results obtained by  different  workers do not always agree.  In  some studies
(Chandara et  al.,  1979a;  Chandra  and Shukla, 1981)  the  brain  manganese con-
centrations were reportedly  an  order  of magnitude higher than  those obtained
by most workers  (Underwood,  1977;  Bonllla, 1978,  1980;  Deskln  et  al.,  1981a;
Chan  et  al.,  1981;  La1  et  al.,  1981b,  1983c).   Furthermore,   1n  recent
studies  by  the same  group  (Chandra  et al.,  1979b;  Murthy et  al.,  1981)  the
brain  manganese levels  are  reportedly different from  values  1n  their other
studies  (Chandra et al., 1979a; Chandra and Shukla,  1981).
     The  available  evidence obtained  with small  laboratory  animals Indicates
that  rats  may  display some of the neuroblochemlcal  changes associated with
manganlsm  1n humans  but  they  do  not exhibit  the wide range  of  behavioral
manifestations  described  1n primates  (Chandra  and Srlvastava,  1970; Chandra
et  al.,  1979a,b;  Singh  et  al., 1974, 1975; Shukla  and  Chandra,  1976, 1977;
SHaramayya  et al.,  1974).   In addition, some  studies have  found clinical


1803A                               6-16                             5/09/83

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                                                                               TABLE  6-4
___ iivwi v i>w A i v. k i i ^v i J vi i iai italic j c 111 i. *vpci iiii^iibui mil IIKI i 3
o
CO
3>
Dose (mq Mn/kq)
Species
Rat
Rat
Rat
Rat
Rat
Rat
Rabbit
>
i Rhesus
^' monkey
Squirrel
monkey
Monkey
Rats and
monkeys
Compound
MnCl2 4H20
MnCl2 4H20
MnCl2 4H20
MnCl2 4H20
HnCl2 4H20
MnCl2 4H20
Mn02
Mn02
Hn02
Mn02
Mn304
Route
Single
l.p. 2.2
1.p. 2.2
1.p. 2.2
1.p. 4.2
1.p. 4.0
l.p. 4.2
1.t. 169.0
1.m. 125,
220
s.c. 250.0
s.c. 39.5
79.0
158.0
Inhalation
Total
535
401
268
189
120
63
169
345b
50QC
355d
711d
1422d
11.6*
112. 5e
1152. Oe
Duration
1n Months
8
6
4
1.5
1
1
24
9
14
3
2
1.5
1
9
CNS Abnormality3
Behavioral H1stolog1cal Biochemical
+ NS NS
+ NS
NS NS +
NS NS +
4- +
- + 4-
t- + +•
+ NS NS
f t NS
,
+ - NS
t - NS
+ - NS
NS
Reference
Roussel and Renaud, 1977
Chandra and Srlvastava, 1970
SUaramayya et al., 1974
Shukla and Chandra. 1977
Chandra et al.. 1979b
Shukla and Chandra, 1976
Chandra, 1972
Pentschew et al.. 1963
Neff et al.. 1969
Suzuki et al.. 1975
UlMch et al., 1979a,b,c
           aNS - Not studied
           bDoses 2 months apart.  Each dose was spread over eight Injection sites.
           C0oses 1 month apart
           dN1ne weekly doses
           eCont1nuous 24 hours/day exposure.  Units are 1n v-g Mn/m^.
CO
CO

-------
features of  the extrapyramldal  disease 1n  most  of  the  exposed animals,  a
scattered  neuronal   degeneration  1n  the   cerebral   and   cerebellar   cortex
(Chandra and  SMvastava,  1970;  Chandra  et al.,  1979b;  Shukla  and  Chandra,
1976), but only occasionally some changes  1n  the  basal  ganglia of  the extra-
pyramidal  system  (Chandra,  1972).    Consequently,  with  the  exception  of
Intratracheally exposed rabbits  described  below  (Mustafa  and  Chandra,  1971,
1972; Chandra,  1972),  studies  with  animals  did not find  the  characteristic
clinical  features   of   the   extrapyramldal   disease  of  manganlsm  described
earlier 1n exposed workers.
    It 1s probable  that the  signs of extrapyramldal  disease  are so subtle 1n
some species  that they  cannot  be noticed without  special  procedures.   There-
fore, Roussel  and  Renaud  (1977)  performed a  study  to  determine If the human
sleep disturbances  observed  1n Parkinson's disease  and  1n chronic manganese
poisoning  appear   1n  the  rat  after  chronic  manganese  Intoxication.   They
found  alteration  of the  sleep-wake  cycle 1n  rats  exposed 1ntraper1toneally
to  2.2  mg Mn/kg  bw dally for 8 months.  Chronic manganese  Intoxication 1n
this  experiment created  an  Increase  1n slow-wave  sleep and  a decrease In
paradoxical  sleep   by  modification   of  the  length  of  the  phases.    However,
these  changes can  be attributed  to  disturbances  1n  cortical  activity rather
than  to  lesions of  the  extrapyramldal  system.
     Experiments with  rats Indicate  that a dally  1ntraper1toneal administra-
tion  of  2-4  mg Mn/kg  bw  produces neuronal  degeneration  1n  the cerebral and
cerebellar  cortex  and  that a  period  of  up  to  120 days  appears  to  be a
threshold  for the  appearance of  microscopic  lesions (Chandra  and  Srlvastava,
1970;  Shukla  and  Chandra,  1976, 1977).   These experiments  also  demonstrate
that  the maximum  number of  degenerated neurons Is present when the amount  of
manganese  1n  the  brain  1s  at maximum, thus Indicating  that  the extent  of


1803A                               6-18                             5/06/83

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damage to brain cells 1s directly related  to  the  amount  of  manganese  present
(Chandra and  Srlvastava,  1970; Shukla  and Chandra, 1977).   Iron  deficiency
1n the presence of treatment with manganese results  1n  the  highest levels  of
manganese on rat brain  tissue.  Some  other  studies  have  shown that biochemi-
cal  changes  (e.g.,   decreased  activity  of   sucdnlc   add  dehydrogenase,
Increased activity of  monoamlne oxldase) may appear earlier  than  hlstologl-
cal alteration  of  the  brain,  I.e.,  even 30 days  after  the  beginning  of  man-
ganese exposure  (SHaramayya  et al., 1974; Shukla  and  Chandra, 1976,  1977;
Chandra et  al.,  1979a,b).   However,  from all  these  experiments  performed  on
rats,  1t  appears  that  the  threshold   for   the  appearance  of microscopic
lesions and biochemical changes 1s when  the manganese 1n  the brain reaches a
level of =4-5 ug/9 of dry tissue  (Singh  et al., 1979).
    Mustafa  and Chandra  (1971,  1972),  and  Chandra (1972)  carried  out  an
extensive  study  on  rabbits  Intratracheally Inoculated  with 400 mg of  MnO ,
corresponding  to  =170  mg  Mn/kg  bw.   After  a  period  of   18-24 months,  the
Inoculated  rabbits developed  paralysis  of  the hind  limbs.   The  animals  also
showed a widespread  neuronal  loss and neuronal degeneration  1n  the cerebral
cortex,  caudate nucleus, putamen,  substantla nlgra and cerebellar  cortex.
There was  a marked decrease 1n brain catecholamlnes, particularly noreplne-
phrlne and  dopamlne,  and  a  reduction 1n the  activity of  some enzymes 1n the
manganese-dosed animals as compared with controls.
    Primates are a better  experimental  animal than  rodents for  studying the
neurological manifestation  of  manganese Intoxication.  Several  studies  with
manganese  dioxide-exposed monkeys have  been  performed  (Mella,  1924;  Neff  et
al.,  1969;  Pentschew et al.,  1963;  Suzuki et al.,   1975),  but  all were  con-
ducted  under  Inadequate experimental conditions (small  numbers  of  animals
were  exposed  to   large,  widely  spaced  doses   of   manganese  by  nonnatural


1803A                               6-19                             5/06/83

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routes) (see  Table  6-4).   However,  these exposures did  consistently  produce
extrapyramldal  symptoms  (excitability,  Intention  tremors,  rigidity  1n  the
extremities)  and/or  histologlcal lesions  (damage  to  the putamen, caudate,
subthalamlc  nucleus,  and  palUdum)  that  were remarkably  similar to  those
described  1n  cases  of human  manganlsm.   Suzuki et  al.  (1975)  administered
subcutaneous  Injections  of 0, 0.25,  0.5 and  1.0  g  MnO  once  a week  for  9
weeks  and  found  that  the  time  of  appearance  of  neurological  symptoms  and
manganese  tissue  concentrations  1n monkeys  were  proportional  to  cumulative
dose  (Table  6-5).   Although the severity  of  symptoms was not  dose-related,
symptoms appeared earlier when higher  doses were administered.
    In  contrast   to   the  experiments   described   above,    Ulrlch   et   al.
(1979a,b,c) observed no neurological or  other  pathological changes 1n groups
of  8   squirrel  monkeys  and  30  Sprague-Dawley  rats  exposed  to Mn00,  aero-
                                                                   o  4
                                     3
sol at 11.6,  112.5  or  1152  ug Mn/m   24 hours/day  (equivalent aerodynamic
diameters  =0.11 u).   These   three   exposure   groups   and   a  control   were
exposed  for  9  months  and  those not  sacrificed  observed  for  6  additional
months.   No  exposure-related  effects on  11mb  tremor   or  electromyographlc
activity  were  observed,   although  the   techniques  used  to  measure  these
parameters were  described  as  sensitive enough  to demonstrate differences 1f
present.  The  authors report  that  there were no clinical  signs of toxldty,
but  no details  of  the  examination were  presented.    The  report of  histo-
loglcal  examination  of  brain tissue  was vague,  claiming  "no  degenerative
changes upon  special  staining."  There  was  no biochemical  analysis.   These
results Indicate  that large amounts  of manganese may be required  to  produce
extrapyramldal effects,  since  manganese levels 1n  the  blood of  the  monkeys
exposed to the highest concentration were  five  times  higher  than 1n the con-
trols after 9 months of  exposure.  Brain manganese  levels were not reported.
1803A                               6-20                             5/06/83

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                                  TABLE 6-5

             Neurological Signs Induced by Manganese 1n Monkeys*

Single Dose
mg Mn (mg/kg)b 0
Time In Weeks and
246
Cumulative
8
Dose (mg Mn)
10 12

14
  158 (39.5)     0      316      632      948     1264     1422

                                                  Tremor,       excitability,
                                                  chorelform  movement,  con-
                                                  tracture of hand

  316 (79)       0      632     1264     1896     2528     2844
                                         Tremor,   excitability,   chorelform
                                         movement, contracture of hand

  632 (158)      0     1264     2528     3792     5056     5688
                                Tremor,  excitability,   chorelform  movement
                                contracture of hand


aSource: Adapted from Suzuki et al., 1975

bDose per  body weight not  reported.   Monkeys weighed 3.5-4.5  kg.   Estimates
 are based on 4.0 kg animal.
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    The chronic  toxldty  of  orally-administered  manganese has not been ade-
quately studied, but  the  available  reports  strongly suggest  that 1t  1s very
difficult, 1f not  Impossible,  to  produce the characteristic  signs of  extra-
pyramidal  neurological  disease 1n  laboratory animals  exposed  via  drinking
water  or  food.   Rats  seem  to be  unaffected by dietary  Intakes  as  high  as
2000 ppm  (Wassermann  and Wassermann, 1977).   Klmura  et al.  (1978)  reported
that feeding with  2000 ppm  of manganese chloride  (564  ppm  Mn)  resulted 1n a
slight  decrease  of   the  brain  serotonin.    Bonllla  and  01ez-Ewald  (1974)
exposed  rats  to  5000 ppm of  manganese chloride  (2180 ppm Mn)  1n  drinking
water,  corresponding  to =306 mg  Mn/kg  bw.   Despite  the  high  manganese
Intake,  none of  the  animals  developed signs  of  extrapyramldal  neurologic
disease,  such  as muscular  rigidity,  tremor  or   paralysis  of  the  limbs.
H1stopatholog1cal  observation  of  the caudate  nucleus revealed  only  moderate
pyknosls  of  some  neurons, and treated  animals  showed  significant  decreases
1n   brain  concentrations  of  dopamlne  and  homovanllUc  add.    Bonllla
(1978a,b)  found an Increase  1n  the concentration  of Y-am1nobutyr1c add In
the  brains of  rats  that were  exposed  to  10,000  ppm MnCl2  1n  the  drinking
water  (=600  mg  Mn/kg  bw)  for  2 months.
     Several  recent experiments have  been  conducted  to  evaluate  the effects
of   prolonged   oral   exposure   to   husmanlte,   manganous   manganic  oxide
(Mn0OJ,   the   major   residue  produced  by  heating  MMT.    The  effect  of
    o 4
chronic  manganese oxide  1ngest1on  1n  rats  maintained  on a normal  Iron diet
(240 ppm Fe)  and on  a low Iron diet (20 ppm Fe) was  studied  by Carter et  al.
(1980),  Rehnberg et  al.  (1980,  1981,   1982)  and  Laskey et  al.  (1982).  Ani-
mals  were  exposed  to four   different  levels  of   Mn30.  1n  their  diet,   50,
400,  1100 and  3550  ppm manganese, corresponding  to  2.25,  18,  50 and 160 mg
Mn/kg  bw, respectively.  Animals  treated with manganese and maintained on a


 1803A                                6-22                             5/09/83

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normal  Iron  diet  or  on  a  low  Iron  diet  did  not  develop  signs  of  extra-
pyramidal neurologic  disease,  such  as  muscular  rigidity,  tremor or paralysis
of  the  limbs.   Recently,  however,  they  have  Indicated  (Gray  and  Laskey,
1980)  that chronic dietary  exposure to 1050  pptn  manganese,  corresponding to
2=140  mg/kg  bw  over  a period  of  2  months, alters  reactive  locomotor  activ-
ity (RLA) 1n mice.   However,  1t  1s  not clear whether the reduction 1n RLA 1s
a  result of  reproductive dysfunction  or  a direct  result from  the action of
manganese on the brain.
    Biochemical changes  1n  the brains of  rats  exposed  to 4.4  mg Mn/kg bw 1n
their  drinking  water  have  been  described {Singh  et  al., 1979), and similar
exposure  to  0.28  mg  Mn/kg  bw reportedly produced  neuronal degeneration 1n
the  cerebral  and  cerebellar  cortex  of  growing  rats  (Chandra  and  Shukla,
1978).   Although  dietary levels  of manganese 1n  the above  studies were not
reported, 1t 1s unlikely  that  the described changes are attributable to man-
ganese exposure.   It  1s  Important to  note that  the above doses are generally
below  the dietary  level  of -20-30  mg Mn/kg bw  that  has  been  found  to be
optimal  for  development  and  growth  1n rats  (Holtkamp  and  H111,  1950;  H111
and Holtkamp, 1954),  and  below the  dally  requirement for  rats  of 50 mg Mn/kg
of  diet   (3-6  mg  Mn/kg/day bw)   that  was  recently  recommended by the NAS
(1978).   Other  recent studies relating biochemical changes  1n  the brain to
administration of manganese are discussed 1n the following section.
6.2.1.   Mechanism of  Manganese  Neurotox1c1ty.   After  some  five decades  of
research  1n   this  field,   the  mechanisms  underlying  the   neurotoxldty  of
manganese and   the  pathogenesls  of  manganese  encephalopathy  have  not  been
definitively elucidated.  Several major  factors contribute  toward  this  lack
of basic  Information.   (1)  The biological roles of  this metal  are not fully
understood;  similarly,  there  1s  an absence  of  a  clear understanding  of the


1803A                               6-23                             5/06/83

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pharmacoklnetlcs,   the  homeostatlc  mechanisms as  well  as  the  deficiency -
sufficiency - toxldty  continuum  of  manganese.    (2)  The  dose-effect  rela-
tionship  1n  manganese encephalopathy has  not been  systematically or  ade-
quately Investigated; Important variables  such as the age, the  species,  the
various forms  of   manganese  and  the  routes  of  administration  of  manganese
must  be  more  seriously   considered.   (3) The  neuroep1dem1olog1cal  data  of
human  manganese  encephalopathy are  Inadequate:    the  provision of  complete
data will  undoubtedly generate new Ideas and  theories concerning  the  neuro-
toxlc  mechanisms   underlying  this   syndrome   (Sllbergeld,  1982).   However,
despite the  shortcomings  just discussed, more recent  studies  employing ani-
mal models of  this disease have provided  some  Interesting  and useful  Infor-
mation  such  that a state-of-the-art  evaluation  of the  possible and plausible
mechanisms underlying  the neurotoxlc effects of  manganese  can be attempted.
Since  the dietary  requirements of  this  metal for man and  animals  are rela-
tively  high  (>40  ppm)  (Underwood,  1977),  the following  discussion focuses
primarily  (although  not  exclusively)   on  studies  where  the  administered
manganese  levels  exceed   the  dietary requirement  by  at  least  two  orders of
magnitude.
    A  number of hypothetical  mechanisms have  been  proposed   to account  for
the  neurotoxlc effects   of  manganese  causing the  pathological  and  neuro-
logical  changes  1n  the  CNS  during manganese  encephalopathy.   However, when
these  mechanisms  are considered  within the  framework of  neurochemlcal con-
cepts,  they  can be grouped Into two broad categories:   1) those that direct-
ly  Implicate altered neurotransmltter  metabolism, and  2)  those that  do not
directly  Involve   dysfunctions  of  neurotransmltter systems, but also  do not
preclude  the latter  as being  secondary,  Indirect  or side effects.
 1803A                               6-24                             5/06/83

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6.2.2.   Altered NeurotransmUter Metabolism.
    6.2.2.1.  EARLY  PHASE  OF RESEARCH  IMPLICATING DISTURBANCES OF THE  CEN-
TRAL  MONOAMINERGIC   SYSTEMS — Early  neuropathologlcal  and   Mstologlcal
findings reveal  certain  neuronal degenerative changes 1n  the  basal  ganglia,
the subthalamlc nuclei and less  frequently  1n  other  brain  regions  1n  chronic
manganese  encephalopathy (Pentschew  et al.,  1963).  From  the more  recent
mapping  studies  (Ungerstedt, 1971) of  the  central  monoamlnergic  systems  1n
the mammalian  CNS,  1t 1s apparent  that some, 1f  not most,  of  the  neuronal
degenerative alterations 1n  manganese encephalopathy occur  1n  the  anatomical
locations  of  these monoamlnergic  pathways.   Studies  1n human  manganlsm  as
well  as  1n animal models of  this  disease  Indicate  that the levels of  mono-
amines  such as  dopamlne,  noradrenallne  and  serotonin  (and  some of  their
metabolites) 1n  the  basal  ganglia are decreased (Neff et  al.,  1969;  Mustafa
and Chandra, 1971; Cotzlas et al.,  1971).   Since these changes 1n  the levels
of  monoamlnes  also occur  1n Park1nson1sm  and  since the clinical  signs  and
symptoms  of chronic  manganese  encephalopathy  show  many  similarities  with
Park1nson1sm, the hypothesis  that  the dysfunction  of the central monoamlner-
gic systems  (particularly the dopamlnerglc  system)  was  the underlying patho-
physlologlcal mechanism  of   chronic manganese  encephalopathy was  first  pro-
posed  (Cotzlas   et  al.,  1971).   Consistent  with  this  hypothesis  was  the
observation that  treatment of patients  with L-dopa,  a classical ant1-Park1n-
sonlan drug, alleviates  the symptoms of this disease (Mena  et al.,  1970).
    6.2.2.2.  RECENT  STUDIES THAT  SUPPORT THE  HYPOTHESIS THAT THE  CENTRAL
DOPAMINERGIC SYSTEM  IS DISTURBED IN  CHRONIC  MANGANESE  TOXICITY — Since the
central dopamlnerglc  system  plays  a key role  1n the normal  functions of the
basal ganglia,  and dysfunctions  of  the  basal  ganglia are clearly discernible
1n  chronic  manganese  encephalopathy,  the proposal  that  a major,  1f  not the


1803A                               6-25                             5/06/83

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major, neurotoxlc  effect  of manganese  Involves  disturbances of  the  central
dopamlnerglc system  appears  most reasonable.  Furthermore,  the  observations
that  1n  the human  brain  the manganese  concentrations  1n the basal  ganglia
are  higher  than  those  1n other  regions  (Curzon,  1975)  and that  1n  manga-
nese-poisoned  animals   this  brain  region  accumulates  more manganese  than
other  regions  (La1 et  al.,  1981b,  1983a,c;  Scheuhammer  and Cherlan,  1981;
Chan et al., 1983)  are  consistent with  this  hypothesis.   Despite the  concen-
sus  that the central dopamlnerglc system  1s  disturbed  1n  experimental  manga-
nese  neuro1ntox1cat1on,  the  precise details of the  temporal, qualitative  as
well  as  the quantitative  aspects  of the  disturbances  are  stm  controver-
sial.   Nonetheless, from a  critical  evaluation   of  recent  studies,  both
published and  unpublished,  the  following scheme,  Identifying  the sites  at
which  the regulation of central  dopamlne  metabolism  1s affected  1n manganese
toxldty (and  hence the  possible mechanisms  of  action of manganese)  can  be
arrived  at  (Figure  6-1).   The  key  feature of  this hypothetical  scheme  1s
that   any   alterations   of  dopamlne  synthesis,    release,  re-uptake   and
metabolism  ultimately  lead  to  changes   1n  dopamlne turnover.   Furthermore,
the  changes 1n  the  steady-state  levels  of  dopamlne  will  give rise to  altera-
tions  of the   Interactions  of   dopamlne  with Us   receptors and  hence  the
alterations  of  the  subsequent   receptor-mediated   events   (changes  1n  Ion
channels and cylcase activities).
     Since  tyroslne  hydroxylase  (TOH)  catalyses  the  rate-limiting step  1n
brain  catecholamlne  biosynthesis, the changes  1n brain  dopamlne  (DA)  concen-
trations 1n manganese  neurotoxldty could simply reflect  the changes  1n the
activities  of  this enzyme.  However, there 1s  evidence  that the decreased
TOH  activity,   observed  ex-v1vo 1n  manganese-poisoned   animals,   cannot  be
1803A                               6-26                             5/09/83

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                                    Tyroslne
re-uptake
       Changes*
        1n Ion
       channels
                                               TOH+  -
                                    release*
                                                                DA
                                                             Turnover
                                                         metabolism by MAO*
                      re-uptake
    Behavioral output
                                                             **
                                                **
                                           Acute
                                          behavioral
                                           changes
                                        (Mn psychosis)
                                                                      **
                        Chronic
                      Extrapyramldal
                     signs  & symptoms
                                     FIGURE 6-1

         Schematic Representation of the Mechanisms of  Actions  of  Manganese
                         on the Central Dopam1nerg1c System
    1803A
6-27
5/06/83

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attributed to the direct  effect  of  the metal on this enzyme  since  Deskln  et
al.  (1981b)  did  not find any  Inhibition  of TOH activity  by 1 mM  Mn2+.   In
young  male  rats  chronically  treated  with  MnCl  »4H  0   (1  mg/m8.  1n   the
drinking  water)  strlatal dopamlne  level  1s Initially  Increased and,  upon
more chronic  treatment  with this manganese  salt,  1s decreased  (Chandra  and
Shukla,  1981).    In  adult  male  rats  chronically   treated  with  MnCl   (10
mg/mfc  1n  the  drinking  water)   TOH   activities  1n  neostMatum,  mldbraln,
hypothalamus and hippocampus,  but not 1n  frontal cortex and  cerebellum,  are
Increased  1n  the first  few months  of  treatment  (Bonllla,  1980).   However,
upon more chronic  treatment with  MnCl ,   TOH  activities   are decreased  1n
the  neostrlatum  but  Us activities  1n  the  other brain  regions  are essenti-
ally the  same as values 1n  control  animals  (Bonllla, 1980).   Thus  1n  manga-
nese-treated rats the  changes  1n brain TOH activities   closely  parallel  the
fluctuations of  brain  dopamlne  levels (Bonllla,  1980;  Chandra  and  Shukla,
1981).    However, manganese  administration   by  oral  gavage  1n  the form  of
MnCl2»4H20   at   doses   of  1,   10  and  20  ug  Mn/g  bw/day   In  rat  pups
during  postnatal development   for  24 days  gives  rise  to  dose-dependent
decreases  1n  TOH activities,  dopamlne levels  and dopamlne turnover  1n  the
hypothalamus  (Deskln   et   al.,   1981a).    Furthermore,   the  dose-dependent
changes  (decreases at  the lowest  dose but  Increases at  the higher  doses)  1n
tyroslne  hydroxylase activities closely parallel the dose-related changes  1n
dopamlne  levels  1n  the  stMatum of  these manganese-treated  rat  pups  (Deskln
et  al.,  1981a).   Employing  a  different  route  of adm1n1strat1n  of  manganese
(1 mg  MnCl2«4H20   per   100 g/day  1.p.),   Aut1ss1er  et   al.   (1982)  also
found  decreases  1n  straltal dopamlne  and dopamlne turnover  1n rats 4  months
after  such treatment.
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    Changes 1n steady-state  levels  of  dopamlne can also be  accounted  for  by
mechanisms that  Interfere with  the  release and  re-uptake  processes at  the
nerve   endings.     For   Instance,    chronic   manganese   treatment   (1  mg
MnCl »4H?0   per   mi   of  drinking  water)  throughout  brain   development
leads to  transient,  age-dependent  but  definite decreases 1n  dopamlne  uptake
by  synaptosomes  Isolated  from  strlatum,  hypothalamus  or  mldbraln but  not
from  the  cerebral  cortex (La1  et  al.,  1982a,  1983b).   These results  are
compatible   with   the   observations   that  admlnlstratln   of   MnCl  »4H 0
(1 mg/mS.  of  drinking water)  throughout  development  gives  rise  to Increased
accumulation of  this metal 1n  all the  brain regions  studied,  with the  excep-
tion  of   the  cerebral  cortex  (La1  et  al., 1981b),  and that  the in  vitro
Inhibitory  effects  of  manganese on   dopamlne  uptake  by  synaptosomes  vary
depending on  the brain  region from which  the  synaptosomes  are  Isolated (La1
et al., 1981c).  However,  the  jm vivo  effects  of  chronic manganese treatment
on  ex-v1vo  synaptosomal  dopamlne uptake  vary  depending on  the dose,  since
treatment  with   a   higher  dose   of   MnCl »4H 0  (10  mg/m2.   of  drinking
water)  leads  to Increased  (rather  than  decreased)  synaptosomal  dopamlne
uptake  measured  ex-v1vo  (Leung et al.,   1982b).   In  comparison with  Us
effects  on  synaptosomal  dopamlne   uptake,  the  effects   of  manganese  on
dopamlne  release have  not  been extensively studied,  although a  recent  study
by  Daniels  et al.   (1981)  reveals  that dopamlne release by  the  rat stMatal
slice preparation 1s stimulated by  5 y.M Mn  *.
    Another  mechanism  by  which  manganese  can  Influence  the  steady-state
dopamlne  levels  1n  the brain  1s through  Us actions  on dopamlne  metabolism
(breakdown).  The key  enzyme  Involved  1n  this  process  1s monoamlne  oxldase
(MAO).  In  earlier  studies  by Chandra and  co-workers  (SHaramayya et  al.,
1974;  Chandra and  Shukla,  1978),   Increased  brain   activities   of  MAO  1n
1803A                               6-29                             5/06/83

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manganese-treated  rats  were  reported.   More  recently,  Chandra  and  Shukla



(1981) found that  the striatal  MAO  activities are only increased during  the



initial  phase  of  chronic  manganese treatment.   Others have  reported  that



brain  MAO activities  in  manganese-treated  rats show  both  increases  and



decreases (Deskin  et  al.,  1981a)  or remain  unchanged  (Kimura et al.,  1978;



Autissier et al.,  1982).  However,  it  is  important to point out  that,  since



MAO in brain and other tissues  exists  in  multiple forms (Lai et  al.,  1980),



none of the studies so far  discussed  (Sitaramayya et al.,   1974;  Chandra  and



Shukla, 1978, 1981; Kimura et al.,  1978;  Deskin et al., 1981a;  Autissier et



al., 1982) set out to address the  effects of manganese on  the  heterogeneity



of MAO.   The  studies  of  Lai and co-workers  (Leung et  al.,  1981, 1982a;  Lai



et  al.,  1982b;  Lai,  1983) were  aimed  at just  trying  to  resolve the  latter



question employing specific substrates (serotonin  being type A  MAO  substrate



and  benzylamine  type B  MAO  substrate)  and  inhibitors   (clorgyline  being



type A MAO  inhibitor and  deprenyl  type  B  MAO  inhibitor).   In  rats  chron-



ically  treated  with  MnCl2'4H20   (1  mg/nu  of   drinking  water)   through-



out development  until adulthood,  only  type A MAO  activity  in the cerebellum



is slightly decreased (Leung  et al.,   1981).   In these treated  rats,  type A



MAO activities in  all the  other brain  regions, type B MAO  activities  in  all



the brain regions as well as the type A to  type  B  MAO  activity  ratios  in  all



the brain regions  remain unchanged.  Furthermore, the development  of  type A



and  type B  MAO   activities  in  the  whole   brain  of  rats   treated  with



MnCl2'4H20  (either  1   or  10  mg/mjl  of   drinking  water)   has  also  been



found  to  be  unaltered (Leung et  al.,  1982a).   On the  other hand,  the  same



study  reveals that both  hepatic type A and type B MAO  activities in treated



animals are increased after  10-15  days of postnatal life.   In  contrast with



the apparent lack  of effects  of manganese  on the A and B forms  of  brain  MAO









1803A                               6-30                             5/09/83

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during   development,   Hfespan   treatment   of   rats   with
(1 mg/mft, of  drinking water for  over  2 years) exerts a modulatory  effect  on
the  age-related  changes of  the heterogeneity  of brain  MAO  (Leung et  al.,
1981).  For  example, consider  the  age-related decreases  1n  type A MAO  and
dopam1ne-ox1d1z1ng activities  1n strlatum and mldbraln of  manganese-treated
rats.   In  these  rats,  the other  effects are  age-related  Increases  1n  the
rates of oxidation of  serotonin, benzylamlne and dopamlne 1n  the cerebellum
not  observed  1n control rats  (Leung  et  al., 1981).   These  results  support
the  hypothesis  that  chronic manganese encephalopathy may  act  differentially
upon  the  developing  and  aging  nervous  system  (La1  et  al.,  1981a,  1983b;
Leung et al., 1981, 1982a;  SUbergeld, 1982).
     In human amphetamine addiction,  the  psychotic behavior  closely resembles
schizophrenia  (Iversen  and  Iversen,  1975).   Neuroleptlcs  that  are  potent
alleviators of the primary  symptoms  of schizophrenia  are  good  antagonists  of
CNS  dopamlne receptors  (Iversen  and  Iversen,   1975).    An  Interesting  and
enlightening parallel  can  be  drawn  between  the  above  two observations  and
the  signs,   symptoms  and  the  pathophyslology  of  chronic  human  manganlsm.
Since chronic  manganese encephalopathy  commences  with  a  phase of  psychotic
behavior ("locura  manganlca"  or "manganese madness") (Cotzlas et al., 1971;
Barbeau et al.,  1976)  resembling that of  schizophrenia and  amphetamine  psy-
chosis,  and  alterations  of the  central  dopamlnerglc  receptor  functions  have
been  Implicated  1n  the pathophyslology  of  the  latter  two syndromes, 1t  1s
reasonable to hypothesize that  one of  the neurotoxlc  mechanisms  of manganese
may  be  Us  effect on  these receptors.   Several  groups of  researchers  have
speculated and  proposed  that  some  of  the  transient neurochemlcal  changes
during  the  Initial  stages  of  chronic and  very  long-term manganese  neuro-
1ntox1cat1on  1n  animals  could  be  viewed as  pathophyslologlcal parallels  to


1803A                               6-31                              5/06/83

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the Initial manifestation of psychotic behavior 1n human manganlsm  (Bonllla,
1980;  Chandra  and  Shukla, 1981;  La1  et  al.,  19836,c).  There 1s some  evi-
dence  that manganese exerts definite effects on the dopamlne  receptors.   The
binding of agonist and antagonist to dopamlne  receptors  1s  potently  enhanced
by manganous  Ions  (Usdln et al.,  1980).   Intraperltoneal   administration  of
MnCl    (10 or  15  mg/kg  bw/day)  to  rats  for  15  days  results 1n  Increased
binding of  the dopamlne  antagonist  splroperldol to straltal  membranes  (Seth
et al.,  1981).  Moreover,  manganese also stimulates brain  adenylate  cyclase
activity  in  vitro  (Walton and  Baldessar1n1, 1976).  Recently  Bonllla  (1983)
found  that strlatal adenylate cyclase activity  1s markedly  decreased  1n rats
exposed to  2.5,  5 and 10  mg  Mn  (as MnCl.)  per mi of  drinking water  for  8
months.   In  addition,  the cyclase  activity  1n the treated animals  does not
respond  to stimulation  by dopamlne  (Bonllla, 1983).   In  rats  chronically
treated   with  MnCl  »4H 0   (10   mg/mfc   of   drinking   water)   throughout
development,  the  Increases 1n  open-field  behavior elicited  with  Intraperl-
toneal amphetamine administration (1 mg/kg bw)  are far  less marked  (Leung et
al.,  1982b).
    6.2.2.3.   IMPLICATIONS  OF   THE  ALTERED  METABOLISM  OF   OTHER  NEUROTRANS-
MITTERS IN MECHANISMS OF MANGANESE NEUROTOXICITY —
    6.2.2.3.1.   GABAerglc  Systems — In   rats   treated   with  MnCl2  (10
mg/mfc  of  drinking water)  for  2 months,  the caudate GABA  level  1s  Increased
markedly  although  the activities of  glutamlc  add decarboxylase  (GAD), the
rate-limiting  enzyme  responsible for GABA  synthesis,  and  GABA-transam1nase,
the  enzyme  which  metabolizes  GABA,  remain  unchanged   (Bonllla,  1978a).
Employing  a  developmental  rat  model  of  chronic  manganese  encephalopathy
(1 mg   MnCl  «4H 0  per   ml   of  drinking   water   throughout  development),
La1 et al.  (1981a)  demonstrated  that  chronic manganese   toxldty  does not
 1803A                               6-32                             5/06/83

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alter  the  brain  regional  activities  of  GAD:   these  results confirm  those
obtained by  Bonllla  (1978a,b)  1n  the rat caudate.   Short-term  1ntraper1to-
neal  treatment  with Mn (15 mg  MnCl  /kg  bw/day  for 15 days)  gives  rise  to a
small decrease 1n cerebellar GABA binding (Seth et al., 1981).
    6.2.2.3.2.   Chol1nerg1c  System — Since the  pathophyslology  of  manga-
nese  encephalopathy  and  that  of   Parklnsonlsm  show  certain  similarities
(Cotzlas et  al.,  1971) and  the chollnergic  system may be  Implicated  1n the
pathogenesls  of  Parklnsonlsm  (Erlckson, 1978),  several   systematic  studies
have  been   Initiated  to  Investigate  the  possibility that  the  neurotoxic
effects  of  manganese  also  Involve  the  chollnergic mechanism  (La1 et  al.,
1981a,  1982a,c;   Bonllla  and  Martinez,   1981).    In  adult rats  chronically
treated   with   MnCl  »4H 0    (1 mg/m8.   of    drinking   water)    throughout
development,  the activities of  ChAT,  the enzyme  that  catalyses  the synthesis
of  acetylchollne,  decrease slightly  1n  cerebellum and mldbraln  whereas the
activities of  this  enzyme  1n the other  brain regions  as  well as  the activi-
ties  of  AChE,  the  enzyme  that catalyses the  metabolism  of acetylchollne,
remain  unaltered  1n  all  the  brain  regions  studied  (La1  et  al.,  1981a).
However,  1n  rats   treated  similarly  (La1   et  al.,  1982a,   1983b),  chollne
uptake by  hypothalamlc synaptosomes shows an Initial  decrease  (at postnatal
ages  between  70 and  90 days)  and  a subsequent  Increase  (at postnatal  ages
between  100  and 120  days).   On the  other  hand, chronic  treatment  with two
doses  of  MnCl «4H 0  (1   and  10   mg/ma,   of   drinking   water)   throughout
development does  not give rise  to  any marked changes 1n  the brain regional
development of  AChE  activities  (La1  et  al.,  1982c).   Bonllla and Martinez
(1981) studied the  activities  of ChAT and AChE  1n different brain regions 1n
adult  rats  treated with  10  mg  MnCl   per   mi   of  drinking  water for  1-8
months and  found  virtually no  changes  1n the activities  of  these enzymes.
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The results of  Bonllla  and  Matlnez (1981) and  those of  Glanutsos  and  Murray
(1982) are compatible with those of La1  et al.  (1981a,  1982c).
    6.2.2.3.3.   Other  NeurotransmUter  Systems — Although   the   lack   of
systematic  studies  precludes  any  critical  and accurate  assessment of  the
possible  roles  of  other  neurotransmltters  1n the  pathogenesls and  patho-
physlology of the neurotoxlc  effects  of manganese, there  1s  some  Indication
that the noradrenerglc system may  also  be  Implicated  (Chandra  et al.,  1979c;
Chandra and Shukla,  1981;  Aut1ss1er et al.,  1982).
    6.2.2.4.   MECHANISMS  THAT  DO  NOT  DIRECTLY   IMPLICATE   NEUROTRANSMIT-
TERS — Recently  three  other  hypotheses  have   been  advanced  to account  for
the  possible  mechanisms  underlying  the  neurotoxlc  effects  of  manganese.
Although these  hypotheses are  presently somewhat speculative  1n nature,  they
provide  Important  theoretical  frameworks   upon  which  current  and  future
studies are designed.
    6.2.2.4.1.   Free-rad1cal-roed1ated  Neuronal  Degeneration — This   mech-
anism  has  been  proposed  by  Donaldson  (1981,  1982)  to account  for  neuronal
degeneration  observed 1n  chronic manganese  encephalopathy  and  other  neuronal
degenerative  diseases.  The  central  theme centers upon  the observation  that
manganese  greatly potentiates  dopamlne autoxldatlon with  the  resultant  gen-
eration  of free  radicals  (e.g.,  superoxlde  anlon,  hydrogen  peroxide  and
hydroxyl  radicals)   giving  rise to  degenerative  changes  (Donaldson,  1981;
Donaldson et al., 1981,  1982).
    6.2.2.4.2.   Autoxldatlon  of  Amines  to  Qulnones  Enhanced  by  Manga-
nese — This  hypothesis  proposes  that  Increased  concentrations of  dopamlne
could  result  1n autoxldatlon  to  qulnones and  liberation  of  free  radicals:
both types of reaction  products are cytotoxlc  and  could  readily give rise to
neuronal  degeneration  (Graham,  1978;  Graham  et  al.,  1978).   Furthermore,
manganese enhances this  autoxldatlon process (Graham, 1983).

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    6.2.2.4.3.    Interactions  with  Other  Essential   Metals  — Interactions
of manganese with other metals can occur  during  Increased  cellular  accumula-
tion of  manganese 1n  chronic  manganese  toxldty  (La1  et  al.,  1981b).   The
Increased cellular manganese could either substitute for  other  metals  (par-
ticularly divalent metal  Ions)  1n their normal capacity (La1  et al.,  1983d)
or  antagonize  other  metals   (e.g.,  manganese 1s  a  potent  Ca  antagonist).
Under both of these conditions, altered metabolic  or  cellular  regulation may
be the predicted result (La1, 1983; La1 et al., 1983d,e).
6.2.3.    Summary.   The available  results  suggest that  an  accurate  dose-
response relationship  for  Inhalation  exposure  and  neurotoxldty 1s  unobtain-
able at  present.  This  1s largely due  to the  fact  that  criteria  for  end-
points  of  effects and routes of  admlnsterlng manganese  differ 1n  various
studies.   The   single  study  using   Inhalation   exposure,   Ulrlch  et  al.
(1979a,b,c), reports  no  behavioral effects after  9 months exposure  to 11.6
     3
y.g/m   Mn«0A.    Unfortunately,   this  study   did   not   Include  biochemical
          «3  ^
data nor  levels  of manganese  1n  brain tissues.    Since  there  are  as yet  no
good biological  Indicators  of  manganese  exposure,  relating  the effects  to
the  tissue  levels of  manganese would  represent  a  state-of-the-art  approach.
Despite  these  shortcomings,   evidence 1s  accumulating  that one of  the key
neurotoxlc effects of  manganese 1s  the disturbance of brain neurotransmltter
metabolism.
     Chronic  exposure  of  adult rabbits (Mustafa  and  Chandra,  1972),  monkeys
(Neff  et  al.,   1969)  and  rats  (Bonllla  and  01ez-Ewald,  1974)  to  different
manganese compounds gives  rise to decreases  1n  brain levels  of monoamlnes,
particularly dopamlne.   More recent  studies Indicate  that  chronic  treatment
of  rats  with MnCl   1n  the  drinking  water  throughout development  1s  asso-
ciated  with  selective regional  alteration of synaptosomal dopamlne  uptake
1803A                               6-35                             5/06/83

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but not  of  serotonin or  noradrenallne uptake  (La1  et  al., 1982b).   In  the
latter  studies,   the brain  regional  manganese  concentrations  show  dose-
dependent Increases  (Chan et al.,  1981,  1983)  and  1n animals  treated  with
the higher  manganese dose,  the  changes  1n  synaptosomal  dopamlne  uptake  1s
associated  with   decreased  behavioral  responses  to  amphetamine  challenge
(Leung  et al.,  1982a).   All  these  observations are consistent  with  the
notion that 1n chronic manganese toxldty the  central  dopamlnerglc  system 1s
disturbed.   This  hypothesis provides  a  mechanistic  explanation  for  the
extrapyramldal disturbances seen  1n human  manganlsm.
    Results  of studies  with  the  rat also strongly suggest  that  age may play
a  role  1n the dose-effect  relationship  1n  manganese  neurotoxldty  (La1  et
al., 1981a,b, 1983b; Leung et al.,  1981,  1982b).   These  results  suggest that
the developing and  the  aging brain show different susceptibility  toward  the
toxic  effects of  manganese.
6.3.   LUNG EFFECTS
6.341.   Human Studies.   The  concept of  "manganese  pneumonia"  (manganese
pneumonltls)  has  been  based  mainly  on  ep1dem1olog1cal  observations.   An
association  between  exposure to  manganese and  a high  rate of pneumonia  was
first  suspected by Brezlna (1921),  who reported that 5  of  10  workers died of
croupous  pneumonia within 27 months  In an  Italian  pyroluslte mill.   Baader
(1932) first  ascribed  the high  Incidence of pneumonia among workers  making
dry cell  batteries  to manganese.   On  the  basis of  his observations  as  well
as  upon   the  reports of  Brezlna  (1921),  Schopper  (1930),  Bubarev  (1931),
Frelse  (1933),  Oantln  Gallego   (1935),  and  V1gl1an1  (1937),  Baader  (1937)
concluded that pneumonia  should  be  regarded  as  an  occupational  disease among
manganese workers.
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     Lloyd-Davles  (1946)  reported the Incidence of manganese pneumonia  1n  the
 manufacture  of potassium permanganate.  The  Incidence  of this disease among
 the  workers  employed  over  the  period  1938-1945 averaged  26  per 1000, com-
 pared  to an  average of 0.73  per 1000  1n  a control group.   All cases were
 diagnosed as  lobar  or  bronchopneumonla.   The Impression was that  the  temper-
 ature  and  general condition of  the  patient  responded more slowly than usual
 to  treatment  with sulfonamldes.  The  possible  causal relationship to  manga-
 nese was not  suspected until  subsequent  Inquiry.  Workers also complained of
 symptoms of  bronchitis and  Irritation of the nasopharynx.  Manganese  concen-
 trations  1n   air, calculated  from  the  MnO  content  of dust,  were  between
                   3
 0.1  and  13.7 mg/m  .   Approximately  80%  of  the particles  were <0.2 u  1n
 size and nearly all  particles were <1 y..
     Lloyd-Davles  and  Harding  (1949)  reported   that  this high  Incidence  of
 manganese pneumonltls  had been  maintained.   On  the  basis  of  the results  of
 chemotherapy  the authors  thought  1t unlikely,  with  the  exception  of  one
 case,  that  bacterial  Infection  played a primary role  1n producing  the con-
 solidation that was  unquestionably  present  1n the lung.  They concluded that
 manganese  dust 1n   suitable  particle size  Introduced   Into  the   respiratory
 system will, without the presence of other factors, cause pneumonltls.
     A  high  Incidence  of pneumonia  associated  with  manganese  exposure  has
 also been  reported  by other  researchers.   Heine (1943) found a high Inci-
 dence  of pneumonia  among workers   1n an  alloy  producing  plant  1n  Aachen,
 Germany, during the  period 1939-1941.  However,  more  careful  analysis of the
 data revealed  that during two  periods  (1936-1938 and  1939-1941) there was  no
 correlation between  high Incidence  of  pneumonia and  high concentration  of
manganese 1n  the air  1n different  parts of  the factory.   Heine concluded
 that factors  other  than  manganese,  such  as draft,  weather   conditions  and
malnutrition,  were predisposing factors for the development of pneumonia.

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    Rodler (1955) discussed  manganese  pneumopathles 1n a  study  of  manganese
poisoning  1n  Moroccan miners.   Cauvln  (1943)  had already  pointed out  the
prevalence of  pneumonltls  associated with  the  high death rate  1n  miners  1n
Morocco  during  the  winter of  1939-1940 and  1947.   Rodler did  not consider
manganese  to  be  the  sole etlologlcal  factor,  but  possibly  a  factor  which
aggravated difficulties resulting from  the  war, poor  housing  and sanitation.
Problems  1n obtaining  X-ray  films  and  necropsies lead  Rodler  to conclude  1t
was uncertain  whether  one was dealing  with an ordinary  pulmonary  Infection
complication  aggravated  by   manganese,  or   subacute   edema,  the  pulmonary
manifestation of a toxic state.
    A  higher   rate  of  pneumonia was  also  reported  1n   basic-slag  workers
(Jotten  et al.,  1939).    Pneumonia  was considered an occupational  disease
related  to the processing,  bagging  and loading  of Thomas slag  obtained  in
the Thomas  process  of making  steel.   The  Thomas slag  contained 6-8% manga-
nese.  Baader  (1937)  assumed manganese and Thomas-slag pneumonia to  be sim-
ilar and  the  chest  symptoms  to  be  caused  primarily by the manganese  In the
slag.
    Wassermann  and  Mlhall (1961) studied  manganese miners,  coal miners and
forest  workers,  all  working  1n comparable  geographical  areas during the
period  1957-1959.   The  Incidence   of  bronchopneumonla   and  pneumonia  was
26-33/1000  for  manganese  miners,   0.8-3.0/1000  for   coal   miners,  and
4.8-24/1000 for forest workers.  Within  each  year rates for manganese miners
were higher than  for  other groups.   In the manganese mine the concentrations
                               3
of  the dust  were 28-840  mg/m , and  the  concentration  of  manganese  ranged
                    3
from  2-200 mg Mn/m   depending on  workplace.   Particles contained  12-30%
manganese  and  the range  of  particles  <5 u was 34-81%.   Silicon dioxide was
1803A                               6-38                             5/06/83

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also  present.   Measurements  showed manganese  concentrations  of  55  and  78
    3
mg/m   1n  respiratory zones  of  workers at  two different  positions.   Radio-
logical  examinations showed  that  25% of  the 820  miners  had radiological
modifications of  varying degrees of severity,  characterized by diffuse pul-
monary  flbrosls  and  the  presence  of  nodules.  Evidence  of  manganlsm  was
reported  1n  19  workers  (2%).    Definitive evidence  of  flbrotlc  or  other
specific lung changes has  rarely been  reported with occupational exposure to
manganese  aerosols  because  radiological  examinations  were not  performed.
Flbrotlc changes  observed  by Buttner  and Lenz (1937) were  almost  certainly
due  to the  20%  silica  present  1n  dust  from  the Glessen  pyroluslte (MnO  )
mines.   Manganocon1os1s  was  confirmed or  suspected  1n 21% of all  of  the
miners  and  the percentage Increased  with  age and  duration of work  1n  the
mines.
    Van  Beukerlng  (1966)  performed a  study  from  1963-1965 1n a  manganese
mine  and  an  Iron  mine   1n South Africa  and  found  a  pneumonia Incidence  of
8.08%  1n over  3000 manganese miners and  5.10% 1n over 1000 Iron miners.   No
chronic manganlsm  was observed.   Sarlc and  Luc1c-Pala1c  (1977)  studied three
groups  of  workers  to determine  whether  long-term exposure  to  manganese  may
contribute  to the  development   of  symptoms  of  chronic  lung  disease.   The
                                                             3
level  of manganese exposure was  reported as  0.4-16.35  mg/m for  workers  1n
                                            3
the  production of   ferroalloys,  5-40  vig/m   for workers  1n  the  electrode
                             3
plant  and  0.05-0.007   ing/m   for   the  workers   1n  the  aluminum  rolling
mill.   The  latter  1s   low  ambient  exposure   and  1s  considered  a  control
group.  The  prevalence  rate  of  chronic bronchitis  and the respiratory symp-
toms  of  phlegm and  wheezing was compared  1n  smokers and  nonsmokers  1n  the
group  of ferroalloy  workers  and  1n the  control  groups.   Chronic  bronchitis
was defined  as  bringing up  phlegm  1n  the morning and during the  day and/or
1803A                               6-39                             5/06/83

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night for at least three winter months  1n  the  last  2 years  or  longer.   Table
6-6  shows  that  chronic bronchitis was  highest 1n smokers 1n  the  high  expo-
sure group.  The percentage of chronic  bronchitis associated with  the  objec-
tive finding of  reduced forced vital  capacity was  5X (7/143)  1n  smokers  1n
the  alloy  plant,  greater  than  1n any  of  the  other groups  (0 or  1 1n  each
group,  hence no  statistical  testing  was appropriate).  The rate of  respira-
tory symptoms  among  smokers  did  not  show an  exposure-response  association
among  the  group.   The  tendency  for  the  rate of  respiratory symptoms  to
Increase with  the extent  of  the smoking  habit was  most pronounced  1n  the
group  of  workers 1n  the production  of  manganese alloys.   On the  basis  of
these  results,  the  authors   suggest  a  possible  synerglsm between  airborne
manganese  and   smoking  habit  1n  the  occurrence  of  respiratory  symptoms.
However, the results  do  not support  synerglsm  because  there 1s no consistent
Increase 1n  symptoms  among  the  group.   Further,  percentages  appear   to  be
additive, but data 1s not sufficient to support this.
    Several reports  suggest  an Influence  of  manganese on  the  rate  of pneu-
monia and  other  respiratory  ailments among Inhabitants living  1n  the  vicin-
ity  of  a ferromanganese factory.   In  two  of  these  three  studies  the ambient
                            !
atmosphere was  visibly polluted with dusts, suggesting simultaneous exposure
to  other contaminants;  therefore, effects  cannot  be definitely attributed to
manganese.    In  1939,  Elstad  reported a  high  rate of lobar  pneumonia among
the  residents of  Sauda, a small  Norwegian  town,  after  the  opening of  a man-
ganese  ore smelting  works  1n 1923.   Data about  manganese  concentration  1n
air  from Sauda  are  not reliable  because  only  one measurement  was  made.  The
report  Indicates  that  manganese  was  contained 1n  visible clouds  of  brown
smoke  polluting  the  atmosphere and   the  dry matter  1n  the smoke was found to
contain  silica.   From 1924-1935,  lobar pneumonia accounted  for 3.65%  of all
1803A                               6-40                             5/06/83

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                                  TABLE  6-6

            Prevalence of Chronic  Bronchitis  1n Groups of Workers
                        According  to Smoking  Statusa«D
Exposure to
Manganese
Smokers
Non-smokers
Totalc
Manganese Alloy
Production
(0.4-16.4 mq/m3)
Number %
46/143 32.2
14/169 8.3
64/369 17.3
Electrode plant
(5-40 uq/m3)
Number %
14/69 20.3
11/102 10.8
28/190 14.7
Aluminum
Rolling Mill
(0.05-0.07 uq/m3)
Number
17/94
4/81
25/204
«
18.1
2.0
12.3
aAdapted from Sarlc and Luclc-Palalc, 1977

^Statistical  analysis  1n  original  publication  1s  multiple  t-tests.   This
 was considered Inappropriate and 1s therefore not presented.

cThe  denominators  do  not  total  369  because data  for  57  past  smokers  are
 not Included.
1803A                               6-41                             5/06/83

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deaths 1n all  of  Norway and 32.3X of all deaths  1n  Sauda,  although  the dis-
ease had been  Infrequent  1n the community until  the operation  of  the plant.
Pneumonia attacked  Inhabitants  of  the  community as  well  as workers  of  the
plant.  Men  working  at the factory  had  a SOX higher mortality  due  to lobar
pneumonia than  men employed  elsewhere.   The number  of pneumonia cases  and
deaths varied with  the tonnage  of manganese alloy produced.   The  occurrence
and types of pneumococd 1n Sauda did not differ from the rest of Norway.
    Nogawa  et  al. (1973)  studied  subjective symptoms  and  ventllatory func-
tion  1n  1258 junior  high  school  students  housed 1n a school  100 m  from a
ferromanganese  plant   and  1n  a  similar  group  of 648  students housed 7 km
away.   Manganese  dustfall   measured  monthly   for   3   years  averaged  200
     2
kg/km /month  1n  the  vicinity  of  the plant  compared  to 20-fold lower  levels
measured at four  other points   elsewhere 1n town.   This  dustfall  level  1s
Indicative  of a  relatively  high  ambient air  concentration,  comparable  to
                  3
about  3-11   vig/m    based  on   Information   1n  Table  3-22.    Atmospheric
concentration  of  manganese  100 m  from  the  plant  was measured  by  a high
                                 3
volume air  sampler at 4.04 vig/m  .   The author  cites  a previous  report  of
                            3
a 5-day average of 6.7  v.g/m  at a  point  300 m from the  plant.
    Data  on  subjective symptoms  and  medical   history of  the student  and
family were obtained  by  the  British Medical Research  Council  questionnaire
for which  the response rate  was  over 9854  1n  each  school.   Of  the  30 Hems
the  following were reported  to  have higher  prevalence In  students  from  the
school near  the  factory:   presence  of sputum 1n winter on arising, presence
of  sputum   1n  summer,  wheezing,  clogged nose,  frequent colds, and  all   six
Items  referring  to  symptoms of  the  throat.    These  were  reported  to  be
statistically  significant  at  p<0.05 but the test  used was  not specified.
1803A                               6-42                             5/06/83

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The  authors   addressed  several  Issues  which  could  affect  reliability  of
results.  Since  ventilation function was  related to  stature,  they compared
the  stature  of students  1n the two  schools  and found no  difference suffi-
cient  to bias  results.   They  noted  that the  exposure  values  at  the  two
schools  could  distinguish among the two groups  because students  at the pol-
luted school  lived within 1500  m of  the plant whereas students from the con-
trol  school   lived   at  least  5 km  from  the  plant.   Furthermore,  data  on
schoolchildren are  far  less likely  to  be biased by  smoking  habit  and occu-
pational  exposure  than data  on adults.   Students  from the  school near  the
factory  had  a higher  prevalence  of  past  history of  pneumonia.   No chronic
bronchitis was reported  at  either  school.  Objective  tests  of lung function
were  measured by the  same  methods  and  the  same Inspectors  at both schools
with  a  91% response  rate.   Students  from the school 1n the polluted area had
lower mean values  than students of  the  control  school for forced  expiratory
volume  analyzed  by  sex and grade.   Mean  values  for the one-second capacity,
one-second ratio  and maximum expiratory  flow were  also  lower  1n  the school
1n  the  polluted area.
     In  a follow-up  study performed  after  dust  collectors  had been Installed
1n  the  factory to reduce the manganese  dustfall, the Investigators examined
respiratory  resistance and respiratory  symptoms (Kagam1mor1  et  al., 1973).
The  authors  concluded  that  the respiratory  symptoms of  students  1n  the pol-
luted area Improved  after manganese  exhaust diminished.
     In  a study on the effect of a-1r polluted with manganese 1n  the  vicinity
of  a plant  smelting pig Iron  and  ferromanganese,  Ookuchaev and  Skvortsova
(1962)  examined  clinical histories  of  1200  children  up  to  16 years of age.
Manganese  concentrations  1n  air  within  a   distance <1 km  from  the plant
                                  3
fluctuated  from  0.002-0.262  mg/m  .   Residents  within 0.5  km of  the plant
 1803A                               6-43                              5/06/83

-------
complained of visible black dust which  accumulated  1n  the  homes.   Wash water
from  children's  hands  contained  38.8  mg  Mn/m2  of  skin  area.   Managenese
was found 1n 62*/4 of  nasal mucosa  smears from 700  children.  Roentgenologlcal
examinations showed pulmonary changes 1n  75% of the children,  many of tuber-
culous  etiology  or  other  residuals  of  past  disease.  However,  H  1s  not
clear  how  many  children were  examined  nor  how  Incidents  were diagnosed  or
scored.   The authors'  report  of   Increased Inflammatory  processes  of  the
respiratory passages due to manganese 1s not quantitatively supported.
    Sarlc et  al.  (1975) studied  acute  respiratory  diseases  1n a  town  con-
taminated by a ferromanganese  plant.   Table 6-7 shows  the 3-year  cumulative
Incidence of  acute  bronchitis  (and  per1bronchH1s) 1n three  exposure zones
of  the town of 31,000  Inhabitants.  The  authors  report  the  differences  1n
the first  three  rows  to  be significant  but multiple  t-tests  performed  are
not  appropriate  for  frequency  data  and  there  1s  no   exposure/response
effect.  The rate of  pneumonia  1n  the population  of the town did  not vary by
pollution zone, nor  did 1t show  the expected difference  between  summer  and
winter periods.  Because the  concentrations of manganese  1n  the  ambient  air
were  higher  1n  summer  than  1n winter,   the question was  raised  whether  the
expected  difference  was  masked   by  respiratory  disease  associated  with
observed  seasonal  variations  1n  the  level  of  manganese.   Incidence rates
were  presented by  age,  but rates  by zone  were not age-adjusted.   Locations
of  the workers'  homes  were  not given  but  workers  represented only a small
percent  of  the  population  since  only  100  lived  1n the town  (Saric, 1983).
The authors also stressed the  fact  that 1n  this  study some other  potentially
relevant factors  may not have been sufficiently controlled.
1803A                               6-44                             5/06/83

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                                  TABLE  6-7

          Cumulative  Incidence  of  Acute  Respiratory  Diseases  During
                             the  3-Year Period*
Mn Concentration
(ug/m3)
Acute bronchitis
and perlbronchltls
Winter
Summer
Pneumonia
Winter
Summer
0.27-0.44
I (N=8690)
Number %

474 5.5
296 3.4

47 0.5
39 0.4
0.18-0.25
II (N=17105)
Number %

1125 6.6
698 4.1

84 0.5
93 0.5
0.05-0.07
III (N=5296)
Number

2261
141

17
19
«

4.3
2.7

0.3
0.4
*Adapted from Sarlc et al.,  1975
1803A
6-45
5/06/83

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    6.3.1.1.   SUMMARY — The studies  of  occupational  exposures support  the
association of  pulmonary  effects and  exposure  to manganese.  Most  of  these
exposures range higher than  the  present  limit  1n  the United States for  occu-
                              3
patlonal  exposure,  5 mg  Mn/m ,   so  they provide  little Information on  the
possible  effects  of  exposures to ambient  levels.   These studies  were  exam-
ined to  determine  1f  exposure levels  could  be  associated with  a severity of
respiratory  effects.    However,   conclusions about  these  exposure/response
relationships are  limited  because exposure values often cover  a broad  range
and pulmonary endpolnts  may not  be clearly  described  or vary among studies.
The health  effects of simultaneous  exposures  have also not  been  thoroughly
examined; for  example,  exposure  to  silica  may account  for  some of  the more
dramatic  Increases 1n pneumonia.
    Table 6-8  summarizes  those  studies  which  report  levels of exposure to
manganese.   The  study  1n  schoolchildren  (Nogawa  et  al.,  1973)  was  suf-
ficiently well  documented  to support an  association between  the  Increased
respiratory symptoms  1n  children and  exposure  to  the dusts  containing manga-
nese from the emissions  of the ferromanganese  plant at  the reported exposure
                   3
levels   (3-11  v.g/m ).   It  1s  plausible  that  exposure   to  manganese  may
Increase  susceptibility  to pulmonary  disease by  disturbing the normal mech-
anism  of  lung  clearance.   Uncertainties  regarding  manganese as  an  etlo-
loglcal  factor  1n  the development  of pulmonary  diseases  (I.e.,  pneumonia)
among workers prompted the  animal studies described  1n the  next  section.
6.3.2.    Animal  Studies.   Studies  with  animals   (Table   6-9)  have  helped
clarify  the effect of manganese  on the lungs.   These  findings  suggest  that  a
primary  Inflammatory reaction of limited duration, without  the  presence of
pathogenic  bacteria,  may  occur   1n  the  lung  after exposure to  manganese.
 1803A                                6-46                              5/06/83

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 CD
 O
 CO
                                                                            TABLE  6-8

                                    Summary of Human Studies  of  Respiratory  Effects  at  Various  Levels  of  Exposure  to  Manganese
 i
 -F*.
Type of Exposure
Manganese miners
(Roumanla)
Exposure Level Chemical/
Particle Size
2-220 mg/m3 34-81X smaller
than 5 u --
various work-
places.
Some S102.
Number Response
820 Increased frequency of pneumonia compared
to coal miners and forest workers.
Radiological modifications 1n lungs of
25X of miners. 2X manganlsm.
Reference
Wassermann and
M1ha1l, 1961
         Manufacture of potassium
           permanganate; workers
           (England)
         Manganese alloy workers
           and worker controls
           (Yugoslavia)
         Emissions from ferromanga-
           nese plant; school-
           children (Japan)
         Emissions from manganese
           alloy plant; town resi-
           dents (Yugoslavia)
0.1-13.7 mg/m3
Mn02/80X <2 u
I   0.4-16.0 mg/m3   NR
II  5-40 ug/m2       NR
III 0.05-0.07 ug/m3  NR
3-11 ug/m3 vs.       NR
10 to 45-fold
lower
0.27-0.44 ug/m3      NR
0.18-0.25 ug/m3      NR
0.05-0.07 ug/m3      NR
    NR     Increased Incidence of "pneumonia" 1n
           workers averaged 26 vs.  0.73/1000 In
           controls.  Increased frequency of
           bronchitis.

   369     Increased prevalence of  chronic bronchitis
   190     1n group I.   Particularly 1n smokers.
   204     Respiratory  symptoms did not vary with
           exposure to  manganese

 1,235     Increased prevalence of  respiratory
   640     symptoms (e.g., sputum,  wheezing, sore
           throat).  Lower mean values 1n objective
           tests of lung function.   No chronic
           bronchitis 1n either school.

 8,690     Incidence rate of acute  bronchitis higher
17,105     1n zone II:  Inconclusive.
 5,296
Lloyd-Oavles,  1946
                                                                          Sarlc and
                                                                          Ludc-Palalc, 1977
                                                                                                                                     Nogawa et al.,  1973
                                                                                                                                     Sarlc et al., 1975
en

O

-v
CO
CO
         All workers were males; race not given.

         NR = Not reported

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                                                                               TABLE 6-9
  oo
  o
                                                              Respiratory Effects with Manganese Exposure:
                                                    Intratracheal, IntraperHoneal and High Dose Inhalation Exposures
       Species
                    Compound
 Concentration
                                                                         Effects by Exposure Type
Exposure
 Hn
Only
                                                                               Bacteria
                                                           Bacteria
                                                             Only
                                                                                                                    Results
                                                                                                                                                   Reference
      Rabbit
                    MnO?
NR
      Nice
                   MnOj
NR
  i
 -C-
 c»
     Mice
tn
\
O
CD
OS
     Mice
                   ferro-
                   manganese
                   Mn02
NR
                                NR
                                                  1 hr/day/39+20 day
                                                 1 hr/day/29 day
Guinea pig
Guinea pig
ferro-
manganese
ferro-
manganese
2350 mg/m3
2350 mg/m3
8 hr/day/
6 mo
8 hr/day/
7.5 mo
                                                                                  NS
                                                 15 m1n/day/
                                                 31-102 days
                 2.70  or  120 m1n/
                 day/15-21  days
                                                  Rabbits  Infected with  pneumococd
                                                  after  39  days.  Bronchial  lesions
                                                  with  leukocyte  and  lymphocyte  Infil-
                                                  tration  noted h1stolog1cally In Mn
                                                  and Mn +  Bacteria groups.  Highest
                                                  mortality 1n Mn + Bacteria group.
                                                  No pathological changes  1n Bacteria
                                                  group.

                                         +         More severe bronchopneumonic changes
                                                  observed  1n mice that  were first
                                                  Immunized with killed  pneumococd
                                                  than 1n mice exposed to Mn02 plus
                                                  viable pneumococd without prior
                                                  Immunization.  No bronchopneumonic
                                                  changes 1n Mn only group.

                                         NS        No hlstopathologlcal changes 1n
                                                  lungs.

                                         NS        Guinea pigs Infected with pneu-
                                                 mococd.   Mortality rate similar
                                                  1n unexposed, unexposed plus Im-
                                                 munized,  exposed,  and exposed plus
                                                  Immunized.

                                         +        No significant difference 1n mor-
                                                 tality rate (=OOOX) between In-
                                                 fected unexposed and Infected ex-
                                                 posed mice.  Mortality rates were
                                                 30-40X lower among Immunized than
                                                 among nonImmunized animals.

                                        +        Mice Infected with pneumococd  and/
                                                 or Streptococcus hemolytlcus.
                                                 Hlstologlcal changes (slight to In-
                                                 tense mononuclear  Interstitial  In-
                                                 filtration of bronchi,  bronchial
                                                 and alveolar epithelium edema)  de-
                                                 pended on length of  exposure.   Ex-
                                                 posed animals  did  not  show Increased
                                                 susceptibility  to  pneumococcus.
                                                                                                              Jotten  et al., 1939
                                                                                                              Jotten et al., 1939
                                                                                                                                              Heine. 1943
                                                                                                                                             Heine, 1943
                                                                                                             Heine, 1943
                                                                                                                                             Lloyd-Davles, 1946

-------
                                                                         TABLE  6-9  (cont.)
 CO
o — 	
Species Compound Concentration Exposure
Rat Mn02 10 mg single 1ntra-
solutlon trachea!
Rat HnCl2 50 mg single 1ntra-
tracheal
o-. Rat HnCl2 5 mg single 1ntra-
' tracheal
Effects by Exposure Type
Mn Mn + Bacteria Results
Only Bacteria Only
t NS NS Rats killed at Intervals from 1 hr-
18 mo postlnJecUon. Inflammatory
response within 15 m1n (bronchlolar
epithelial changes) to 24 hr (mono-
nuclear reaction 1n the Inter-
stitial tissue). Subsequently,
widespread pneumonia and a granulo-
matous reaction sometimes developed.
+ NS NS Rats killed at Intervals from sev-
eral minutes to 8 days postlnjec-
tlon. Death due to gross pulmonary
edema within a few minutes, but
lung histology normal.
+ NS NS Rats killed as above (50 mg). Death
due to pulmonary edema In 1/3 of the
Reference
Lloyd-Davles and
Harding, 1949
Lloyd-Davles and
Harding, 1949
Lloyd-Davles and
Harding, 1949
   Guinea pig
             50 mg
Intratracheal
en
•x
o
CO
CO
Monkey


Monkey



Mice




Mice
Mn02



Mn02




Mn02
                               3 mg/m3          22 hr/day/5 mo


                               0.7 mg/m3        22 hr/day/5 mo
                               3 mg/m3
                               0.7 mg/m3
22 hr/day/2 wk
22 hr/day/2 wk
NS


NS



NS




NS
         rats within 1 hr.  Alveoli normal 1n
         survivors after 1 wk, but mucosal
         cells 1n the bronchial epithelium
         remained abnormal.

+        Simultaneous Inoculation of Mn and
         Candida alblcans.  Inflammatory re-
         action developed earlier, was more
         Intense and widespread, and eventu-
         ally produced more flbrosls (>120
         days) 1n the Mn * Bacteria group.

NS       Pulmonary congestion.
NS       Pulmonary changes were less severe
         and appeared later than 1n 3 mg/m3
         exposure.

NS       Inflammatory changes were generally
         reversible after 2 mo, at which
         time desquamatlon of the bronchial
         epithelium was observed.

NS       Same pulmonary changes as In the
         3 mg/m3 mice.
                                                                                                                                            Za1d1 et al., 1973
                                                                                             Nlshlyama  et  al.,
                                                                                             1975

                                                                                             Nlshlyama  et  al..
                                                                                             1975
Nlshlyama et al.,
1975
Nlshlyama et al.,
1975

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                                                                          TABLE  6-9  (cont.)
 CD
 O
 Gi
     Species
Compound
Concentration
Exposure
  Effects by Exposure Type

 Mn       Hn +      Bacteria
Only    Bacteria      Only
                                                                                                                   Results
                                                                                                                               Reference
    Guinea pig
    Mice
             50 mg
             109 mg/m3
                 single Intra-
                 tracheal
                 1-3 hr/day/
                 1-4 days
                                                                                 NS
 i
 in
 o
    Rat
             50 mg
                                                Intratracheal
                                                               NS
    Guinea pig
             22 mg/m3
                                                24 hr
                                         NS        Hn  particles  were  not  phagocytlzed
                                                  until  30 days postlnjectlon.   De-
                                                  generative  changes In  the  macro-
                                                  phages,  Infiltration of  eoslnophlls,
                                                  and some retlculHIs at  >90 days.

                                         +         Mice Infected with Klebslella  pneu-
                                                  monia  within  1-5 hr after  final  3-hr
                                                  exposure.   Inflammatory  response
                                                  was most marked after  the  4th  expo-
                                                  sure to  Mn  only, but no  deaths.
                                                  Mortality was 2-fold higher  In the
                                                  Mn  + Bacteria group than In the
                                                  bacteria only group,  and  mortality
                                                  was greatest  In animals  with  long-
                                                  est Intervals between  MnO? exposure
                                                  and bacterial challenge.

                                         NS        Most of  the animals showed normal
                                                  pulmonary histology after  30 days,
                                                  although some had  nodules  of dust,
                                                  macrophages and thin retlculln
                                                  fiber.   Enzyme activities  from lung
                                                  fractions normal.

                                                  Initial  depression of  number and
                                                  phagocytlc  capacity of macrophages
                                                  and bacterial clearance  mechanism,
                                                  but nearly  all Mn02 was  cleared  from
                                                  the lungs by  7 days postexposure.
                                                  The Inflammatory reaction  was  more
                                                  pronounced  In the  lungs  challenged
                                                  with bacteria, but tissue  histology
                                                  was normal.
                                                                                                                          Shanker et al., 1976
                                                                       Malgetter et al.,
                                                                       1976
                                                                                                              Singh  et al., 1977
                                                                                                              Bergstrora,  1977
    NS = Not studied; NR = Not reported
o
cr
CO

-------
H1stolog1cal examination of lung tissue from animals  exposed  to  manganese  by
Inhalation  Indicates  that  slight   to  Intense  leukocyte  Infiltration  char-
acterizes the  acute  pulmonary responses (Jotten et al.,  1939;  Lloyd-Davles,
1946;  Malgetter   et  al.,  1976;  Bergstrom,   1977).    Since  other  clear-cut
hlstologlcal  findings  have not  been observed  1n  acute  manganese  exposure,
Bergstrom  (1977)  suggests that  the acute  pulmonary  effects  may have  been
overlooked 1n  the early  Inhalation  studies based only on  hlstologlcal  evalu-
ation  (Heine,  1943).   Bergstrom (1977) also  notes  that  the  occurrence  of  a
primary  Inflammatory reaction   1s  consistent  with  the  Ineffectiveness  of
usual  antibiotics used  for   pneumonia  treatment 1n   the  acute   phase  after
MnO  exposure.
    The  available experimental   evidence  Indicates  that  1t 1s  unlikely  that
exposure  to manganese could be  solely  responsible for the development  of the
serious  pathological changes  1n  the lungs  (e.g.,  bronchopneumonla or pneumo-
n1t1s, chronic Inflammatory effects  such  as  flbrosls); Instead,  1t 1s  likely
that  susceptibility  to  Infection 1s Increased.  Table  6-9  shows the pulmon-
ary  effects  of exposure to manganese with and  without simultaneous  exposure
to  bacteria.   Since the pulmonary reaction after  exposure  to  manganese  1s
more  pronounced   1n  lungs challenged  with  bacteria   (Jotten  et  al.,  1939;
Heine, 1943;  Lloyd-Davles, 1946; Za1d1  et  al.,  1973;  Malgetter et al., 1976;
Bergstrom,  1977), and because sufficient  evidence  Indicates that exposure to
manganese  has a  depressive effect  on  the number and phagocytlc capacity of
alveolar  macrophages  (Waters  et al.,  1975;  Graham et  al.,  1975; Shanker et
al.,  1976;  Bergstrom,   1977),  the  serious pathological changes  should prob-
ably  be  attributed  to  decreased resistance  to  respiratory  Infection and the
presence  of  pathogenic  bacteria.  The results  of the study by Jotten et al.
(1939) with  Immunized mice further  suggest that manganese may Interfere with


1803A                               6-51                             5/06/83

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some  1mmunolog1cal  mechanism,  rendering  the  animals  more  susceptible  to
Infections.   Consequently,  some  of the  earlier  observed  cases of  manganese
pneumonia might  have  had  a bacterial  genesis, particularly among  population
groups whose  exposure to  manganese was low  and  risk of airborne  Infection
was high.
    The  experimental  data on  the  pulmonary  toxldty  of  manganese 1n  Table
6-9  consists  of  studies  at high  doses of  short duration  and often  using
Intratracheal  administration,   therefore  not  showing  a  consistent  dose-
response relationship.   For example,  Singh  et al.  (1977)  reported  that  an
Intratracheal  Inoculation  of  50  mg   MnO    did  not   produce  significant
biochemical  or pathohlstologlcal changes 1n  the  lung  tissue,  although one  of
the  authors  observed  1n   his  earlier  Investigations  that  MnO  alone  pro-
duced  flbrotlc  reaction   under  exactly  the same  experimental  conditions
(Za1d1 et al.,  1973;  Shanker  et al., 1976).  In  other  studies pathomorpho-
loglcal  changes  were observed 1n   the  lung  tissue  of experimental  animals
after  Intratracheal   Inoculation of  10  mg  MnO   (Lloyd-Davles and  Harding,
1949;  Levlna and  Robacevskaja,  1955),  and  even after  5  mg  MnCK  (Lloyd-
Davles and  Harding,  1949).  However,  1t 1s  reasonable to  conclude  that the
usually  rapid  lung  clearance  of Inhaled manganese (Malgetter  et  al.,  1976;
Bergstrom, 1977)  1s Ineffective 1n  the  Intratracheal  Inoculation,  so  that  an
amount of 5 mg manganese  1s sufficient to Induce  local lesions 1n the lung.
    Although  Inhalation  studies represent  a much  better  experimental  model
for  studying  pulmonary  effects, the  results  obtained  are still Insufficient
for  estimating  accurate  dose-response relationships  for  Inhalation exposure
to  manganese.   For  example,  Heine (1943)  found  no pathological  changes  1n
                                                    3
the  lungs  of  guinea pigs exposed  to  2350  mg/m   ferromanganese  dust  8
hours/day for  up to  200  days.  Further,  1n experiments  on  rats  exposed  to
             3
150 mg MnO^/m  for up to  15 months, no signs  of pneumonia were observed.

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    Table 6-10  contains  more  recent  Inhalation studies  administering  lower
doses and  using longer  time  periods;  hence,  these  studies are more  useful

for delineating effects at level near  ambient exposures.

    A  series  of  Inhalation   studies  reporting  acute  exposures  to  Mn 0
                                                                          o A-
aerosol   are  supportive  of  the pulmonary  toxldty of  manganese  (Adklns  et

al.,  1980a,b,c).   Charles River  CD-I  mice  (4-8/group)  were  exposed  for  2
                                                                           3
hours  to  Mn.,0.  aerosol  1n  concentrations   ranging  from  0-2.9  mg  Hn/m .

Dry/wet   ratios  of  tissue weight were examined  as  an  Index of edema  and  the

results   were  not considered  to be  biologically significant (Adklns  et al.,

1980a).    Another  experiment   was  designed  to  examine   the  suppression  of

pulmonary defense  mechanisms   after acute  Inhalation  exposure to  manganese.
                                                                   3
Exposure  of  groups  of  22-195 mice for  2 hours  to  897  ug Mn/m  signifi-

cantly  reduced  the   total  number  of mlcrocytlc  pulmonary  cells  (p<0.01,

t-test), but did not  affect  the differential cell count  (macrophages,  PMNs,

lymphocytes).   Reduction  1n   phagocytlc   capability  was  not  statistically

significant (Adklns et al., 1980b).

    Adklns   et  al.   1980c   also  exposed   20-80  mice/group  to   Mn_0
                                                                          O *r
                3
(0.22-2.65  mg/m )  and  subsequently  to  airborne  Streptococcus   pyogenes.

Animals   exposed to  manganese  showed  higher mortality  rates  than  Infected
                                  3
control   animals  (at  0.38 mg  Mn/m  a  7.5% mortality  Increase was  within  95%
confidence  limits).    These   results  support   the  concept  that  a  primary

Inflammatory reaction  to manganese  can  occur 1n the  respiratory tract  after

exposure to  manganese,  causing a decrease 1n  the resistance  to respiratory

Infections.

    UlMch  et   al.  (1979a,b,c) exposed  Sprague-Dawley  rats  (30/group)  and

squirrel  monkeys  (8/group)   to  Mn00,  aerosol  at concentrations of  11.6,
                                   J 4
                          3
11.25 and  1152 ug   Mn/m   for  24 hours/day,  7  days/week for  9  months.
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                                   TABLE  6-10



Respiratory Effects  with  Manganese  Exposure:   Inhalation  Exposures  at  Low Doses
CD
O
CO
3>
Species
Mice, Charles
River, CD-I
(20-195/group)
Mice. Charles
River, CD-I
(20-41/group)
Rats, Sprague-
er> Dawley (30/group)
^Monkeys, squirrel
•**• (8/group)
Monkeys, Rhesus
(7 exposed,
5 controls)
Monkey, Rhesus
A) 3 exposed
8) 2 exposed
Rats
(74/group)
Hamsters, golden
^ (60/group)
^
Compound
Mn30-4
aerosol
Nn304
aerosol
Mn304
partlculate
""304
partlculate
Mn02
dust
Automotive
emissions
containing
Mn
Effects
Concentration Exposure Mn Mn +
(particle size) Only Bacteria
897 ug/m3 2 hr - NS
(1-3 um)
220-2650 ug/m3 2 hr NS ++
(1-3 um)
Control 24 hr/day, - NS
1 1 . 6 ug 9 mo
112.5 ug
1152 ug
(<2 um)
100 ug/m3 24 hr/day - NS
to 66 wk
22 hr/day, * NS
A) 3000 ug/m3 10 mo
B) 700 ug/m3
117-131 ug/m3 8 hr/day, - NS
(0.3 um) plus 56 day
other partlcu-
late and gases

Bacteria Comments Reference
Only
NS Normal cell concentration (macro- Adklns et al.,
phages, PMNs, lymphocytes). No 1980b
Increase 1n extracellular protein
(no edema). No effect on phago-
cytlc capability.
«• (Bacteria only - control) Adklns et al..
Mean mortality rate Increases 1980c
over controls as Mn concentration
Increases. Enhanced growth of
streptococci over controls.
NS No exposure related gross or UlMch et al.,
microscopic alterations or effects 1979a,b,c
on mechanical or ventllatory prop-
erties of the lung. (No exposure
related effect on EM6 or 11mb
tremor .
NS No abnormal changes seen on gross Coulston and
or microscopic examinations. In- Griffin, 1977
crease of Mn In lung. 8/12 had
acarlasls.
NS Inflammatory changes earlier 1n A Suzuki et al.,
than B; granular rather than In- 1978
f1ltrat1ve shadows. After 10 mo
hyperplasla of lymphold tissue,
pulmonary emphysema. Deposits of
dust 1n macrophages.
NS No gross or microscopic changes Moore et al..
In the lung. 1975
o
\NS = Not studied
00
CO

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Although blood and  tissue  levels  of manganese were  elevated  1n both species
at the  high  dose after 9  months,  significant exposure-related  effects  were
not reported 1n  either  species  by  neurologic,  histopathologic,  organ weight,
pulmonary function  or  hematologlc  observations.   The Investigators evaluated
pulmonary physiology data  for  the  4 exposure  groups at  5  points 1n time but
the  report  presents  only   the  mean percent  of  preexposure  values  after  9
months  of exposure  (Table  6-11).   Few  statistically significant differences
were  found  using   the  Mann-Whitney U  test.   Mean value showed  Increased
airway  resistance 1n  some  of the exposed groups.   The  authors  conclude that
there  were  no  time-related  effects  or  trends  attributable   to  manganese
exposure, but  the  data  to support  this  are not  displayed.  However,  there
are  limitations  1n  this study.  It  1s  not  clear which  two groups  were com-
pared  statistically,  which  1s partlculararly  confusing  since there  are  4
groups  1n  the experiment.   Data  over   time  1s  not presented and  numbers  of
animals  tested are  small.   The  authors  state  that lungs were  free of Inflam-
matory  and/or  degenerative  changes but  do  not  describe  the  scope of  the
microscopic  examination.   Serum biochemical  evaluations showed  some evidence
                                                                  3
of  hypophosphatemla 1n  the male  rats  exposed   to  1152  ug  Mn/m ,  but  the
toxlcologlc  significance of  this finding  1s  uncertain.   The amount of manga-
nese present 1n  the diets of the animals was not stated.
                                                                            3
    Coulston  and Griffin  (1977)  exposed 7  rhesus monkeys to  100  ug  Mn/m
as  partlculate  Mn  0   due  to   combustion  of  MMT for   6,  12  or  15  months.
                  *5 T"
The  conclusion states  that  there  were  no  abnormalities  on gross  or micro-
scopic  examinations.   However, no  objective  measures   of  pulmonary function
were  reported.   Per1bronch1olH1s  and  pneumonltls was  reported  1n associa-
tion  with Infection to mites  (acarlasls)  1n 6  of 7 exposed monkeys,  and  a
statistically  significant  Increase  1n manganese  1n the  lungs  was reported 1n
2 controls.

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                                 TABLE  6-11

                      Pulmonary  Physiology  Data  for  Male
              and  Female  Monkeys  After Nine Months of  Exposure*
   Evaluation
Group
        Mean Percent Of
      Pre-Exposure Values
Males (n=4)        Females (n=4)

Respiratory rate
Vy (tidal volume)
MV
R (pulmonary flow
resistance)
Cdyn (dynamic
compliance)
N (1% N2)

I control
II 11.6 vig
III 11.25 vig
IV 1152 vig
I
II
III
IV
I
II
III
IV
I
II
III
IV
I
II
III
IV
I
- Ir
III
IV
( I
Mean + SEM b
134 + 31
88 + 9
175 + 32
157 + 32
90 + 4
141 + 33C
98 + 16
94 i 11
122+30
124 + 29
160 + 22
143 + 29
209 + 125
104 + 9
365 + 83
257 + 124
91 + 33
125+45
54 + 10
123+23
103 + 12
116 + 23
105 + 2
74 + 7
Mean + SEM
150 + 14
106 + 10
149 + 9
143 + 14
115 + 15
104 + 14
185 + 36
100 + 24
205 + 30
116 + 19
272 + 46
136+27
80 + 35
204 + 45
99 + 39
308 + 272
106 + 23
74 + 13
153 + 43
92 + 33
192 + 20
95 + 10
156 + 28
73 + 11
aAdapted from Ulrlch et al., 1979c

bThe  authors  state  that  the Mann-Whitney  U was  used for  statistical  com-
 parisons, and  the standard error  of  the mean 1s presented  to  provide some
 Index of the variability.

cp = 0.028
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       6-56
                        5/06/83

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    Moore et  al.  (1975)  studied  chronic  exposure  to automobile  emissions
from the  combustion  of  gasoline with  MMT  additive.   The average  concentra-
                       3
tlon was  117  ixg  Mn/m   over  56  days,  8  hours/day.   No  gross  or  micro-
scopic  changes were  seen  1n  lungs  of exposed animals.   (For a  review  of  the
toxicology of MMT see Stara et al.. 1973).
    6.3.2.1.   SUMMARY — Information from earlier  studies  on  the  pulmonary
toxldty  of manganese 1s  Incomplete  and  sometimes  contradictory,  particular-
ly  In  respect  to the exposure-response  relationship.   Some pathomorphologl-
cal changes  1n  the lung  tissue  of experimental animals were  observed after
Intratracheal  Inoculation  of  10  mg  MnO   or  after  5  mg  MnCK  (Lloyd-
Davles  and Harding, 1949).
    Inhalation studies  represent  much  better experimental  models  for  study-
Ing pulmonary  effects.    Experimental  evidence  Indicate that  acute resplra-
                                                                   3
tory effects  appear when the  level  of exposure  exceeds   20  mg/m  of  MnO?
(Bergstrom,  1977;  Malgetter  et al.,  1976).   Although  studies of  toxldty
after chronic exposure  have deficiencies which  limit  their  use for delineat-
ing exposure-response   levels,  several  studies exist  1n which experimental
animals  were  exposed  to MnO  as  Mn30.  particle  or  aerosols  of  resplrable
particle  size, an  appropriate form  for  health risk evaluation for airborne
manganese.  Suzuki  et  al. (1978)  reports positive  radlologlc  findings after
10  months  of  exposure  to  manganese  dioxide  dust  at higher levels,  0.7
    3
mg/m ,  and  Adklns  et al.  (1980c)  report Increased mortality  from Infection
                    3
1n mice at =0.4 mg/m .
    Table 6-10 shows  the two studies  1n which  the lowest  levels of exposure
to  manganese  occurred   (Ulrlch  et  al.,  1979a,b,c;   Coulston and  Griffin,
1977).    These  report  no effect  due  to the  exposure,  but  the  latter,  1n
particular,  had   deficiencies  which   reduce   confidence   1n  the  negative
1803A                               6-57                             5/06/83

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results.   The  existence  of  three negative  studies  1n this range  supports  a
lack of gross toxic effect at this level.
6.4.   REPRODUCTIVE EFFECTS
6.4.1.   Human Studies.   Impaired  sexual  behavior 1n  workers  showing  symp-
toms  of  manganlsm  has often been  reported.   Diminished Hbldo  or  Impotence
have been the most common symptoms  (Penalver,  1955;  Mena  et  al., 1967;  Emara
et  al.,  1971;  Chandra et  al.,   1974;  Cook  et  al.,  1974).   Rodler  (1955)
reported  Impotence  1n -80% of  his  patients, although this  symptom can  be
preceded   by  a  short  phase of   sexual  stimulation.   Emara  et  al.  (1971)
reported  one  case  of  hypersexualUy which  was  not  followed  by  diminished
libido.
6.4.2.   Animal Studies.  Influence  of  manganese exposure on  sexual behav-
ior 1n experimental  animals has not  been  reported   1n  the literature.   How-
ever,   studies  have   been  done  on  hlstologlcal,  biochemical  and/or   mor-
phological   changes.   Chandra  (1971)  reported that  1.p.  administered  MnCl
(8  mg/kg  bw dally)  1n rats caused  no  hlstologlcal  changes 1n  seminiferous
tubules for up to 90  days of exposure.  Marked degenerative  changes In  these
tubules did occur  after  150 and 180 days of  exposure.  The  affected tubules
(~50%) showed marked  depletion  or  absence  of spermatlds and  spermatocytes
and a number  of  degenerated  spermatogenlc  cells.   Chandra and  colleagues
Initiated a  series  of experiments 1n rats  Injected  1.p.  with  6 mg  Mn/kg  bw
dally   (as   MnSO »4H,.0)  1n  order  to  elucidate   the  mechanism  of  testlcu-
               4    c
lar damage  (Singh  et al.,  1974,  1975;  Tandon et al., 1975;  Chandra  et al.,
1975).   The  exposure periods  were  from 25-30 days.   The number  of  tubules
showing  degenerative  changes  was less  (~10X) than  1n the study  by  Chandra
(1971).  The  rest  of  the tubules  and  Interstitial   tissue showed  no morpho-
logical changes.   Degenerative changes were accompanied by a decrease 1n the
activity  of  some  enzymes,  such  as  sucdnlc  and lactic dehydrogenases  (SDH

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and LDH), and add phosphatase  (AP), and  an  Increase  1n manganese concentra-
tion  1n  the testes.   The  authors explained  their  hlstologlcal  findings  as
manganese-Induced Inhibition of enzymes Involved  1n energy  metabolism of the
cells.   Simultaneous  administration  of   zinc  had a  beneficial  effect,  but
various chelatlng agents failed to Improve morphological changes.
    In  another  experiment  1n  rats,  Shukla  and Chandra  (1977)  administered
MnCl  »4H 0  1.p.  (15  mg/kg  bw  dally)   for  15,  30   or 45  days.   An  In-
crease 1n manganese concentration  1n brain,  liver and testes  was accompanied
by  a  decrease  1n nonproteln  sulfhydryls,  and a reduction  1n  activity  of
glucose-6-phosphate  dehydrogenase  and   glutathlone   reductase.   This  was
explained by  possible reduction  of  cystelne content  of the tissues  due  to
formation of  manganese-cystelne  complex   and  Us excretion  from  the  body.
Oral  administration   of   MnCl_»4H_0   (50  ug/kg  bw  dally)   to  rats  for
180 days  did  not Induce  chromosomal  damage  1n the bone marrow or spermato-
gonlal cells (D1ksh1th and  Chandra, 1978).   In  this experiment, however, the
dally  oral  dose  was  at  least  500 times lower  than  the  recommended  dally
dietary Intake of manganese.  This makes  1t  very  difficult  to evaluate these
data.
    In  rabbits   a  single  Intratracheal   Injection  of  MnO    (250 mg/kg  bw,
particle  size  <5 v.m)  resulted  1n marked destruction  and  calcification  of
the   seminiferous  tubules  at   8   months   after  exposure   (Chandra  et  al.,
1973a).  There  was  extensive desquamatlon and  cytolysls of various elements
of  the  epithelium with  markedly  degenerated  spermatocytes  and spermatlds.
Females kept with experimental  males did  not become pregnant, but no details
on  the  reproductive  performance  testing  procedure were given.   Similar  to
results  observed 1n  rat  experiments,  the activities  of  some  enzymes were
significantly reduced  (ATPase,  SOH and  AP).   Seth et  al.   (1973)  using the
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same  experimental  design  1n  rabbits,  showed that  degenerative changes  1n
~10-20%  of  seminiferous  tubules were  present  at  2  months after  exposure
and gradually Increased showing severe changes at 8  months.
    In an attempt  to  Investigate whether the early hlstochemlcal effects  of
manganese on  testlcular  enzymes occur  prior  to morphological  changes,  Imam
and  Chandra  (1975)   administered  MnCl  »4H 0  1.v.   to  rabbits  (3.5  mg/kg
bw  dally)  for  up  to  30  days.  Manganese  Inhibited  SDH  activity   1n  semi-
niferous tubules 5 days  after  the beginning  of  exposure, when  morphological
alterations  were not  apparent.   They  demonstrated that manganese affects the
germinal function  of  testlcular  tissue without disturbing  steroldogenesls,
and reached  the same conclusion on manganese-Induced  disturbances  1n energy
metabolism as 1n rat experiments.
    Jarvlnen  and  Ahlstrom (1975) exposed  female rats  to  manganese  1n  diet
from  weaning   for  8  weeks   and  during   pregnancy.    MnSO.»7H_0  was  the
dietary additive and  final  manganese concentrations In  the  diet were 4, 24,
54,  154,  504  and  1004  mg  Mn/kg.   Exposed  animals had normal reproductive
performance.   No  gross  malformations  or  bone  structure  anomalies  were
observed  1n  the  fetuses.   Body  weights,  dry matter  and  ash  contents  were
also  not affected  by  dietary exposure to manganese  of their dams.  At higher
manganese levels (104, 504 and  1004  ppm) there was  an Increase  1n whole body
content  of  manganese 1n fetuses as  well  as 1n  livers of their dams, but no
Increase 1n Hver manganese was  found In nonpregnant females.
    Epstein et  al.  (1972)  used  a modified  dominant  lethal  assay for  174 test
agents.   MnCl  was   Injected  1.p.   to   male  ICR/Ha  Swiss   mice (20  or 100
mg/kg  bw).   Animals  were mated  for  eight consecutive  weeks and the authors
classified  MnCl   as  an  agent  producing early fetal  deaths  and prelmplanta-
tlon  losses within control  limits.   In  a similar study using dominant lethal
 1803A                               6-60                             5/06/83

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test procedures  3orgenson  et al.  (1978)  administered MnS04  to  male  rats  by


single  or  multiple gavages  at  three  dosage  levels  (levels  not mentioned),


and concluded that MnSO, was not mutagenlc to the rat.
                       4

    Gray and  Laskey  (1980)  Investigated  the reproductive development  associ-


ated  with  chronic  dietary  exposure   to  manganese.   Male  mice  (CD-I)  were



exposed  to 1050  ppm  Mn as  Mn 0   1n  a  casein  diet from  day  15  of  lacta-
                               *J *T

tlon  to  90 days  of age.   Wet weights of  preputlal  glands,  seminal vesicles


and testes measured at  58, 73 and 90  days  of age  were  lower  1n exposed than



1n control animals.   Body  and  liver  weights were not affected.  Reproductive


performance was not tested 1n this study.



    Laskey et  al.  (1982)  designed a follow-up study 1n  rats  to evaluate the


effects  of dietary  manganese  exposure  and  concurrent  Iron  deficiency  on


reproductive  development.   Long-Evans rats were exposed beginning on  day  2


of mothers'  gestation through 224 days  of  age  to 0, 350,  1050  and 3500 ppm


manganese  added  as   Mn«0    (average   particle  size  1.02  vim)  to  a  normal



(240  iig  Fe/g;  50 ug  Mn/g)  and  an  Iron-deficient  (20  vig  Fe/g;  50  ug


Mn/g)  diet.   Testes  weights  were not affected,  but of  particular Interest


was the  manganese dose-related decrease  1n serum testosterone  concentration


without  a  concomitant Increase  1n  serum LH concentration.   Fertility,  mea-


sured  as percent  pregnant,  was reduced  1n  females  at 3500  ppm  (females were


mated  with males  from the  same dosage group).   Although this difference was


statistically  significant  compared   to  controls,  all  other  reproductive


parameters (Utter s1zef/  number,  of  ovulatlons,  resorptlons and prelmplanta-


tlon  deaths,  as  well  as  fetal  weights) were within control values  1n all


manganese-treated groups.



6.4.3.   Summary.  Except  for  reports  of Impotence  1n  patients  with  chronic



manganese poisoning,  human data are largely lacking.
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    Existing  animal   data  are  most  concerned  with  possible  reproductive
failure  1n  males.   Chandra  and  co-workers  suggested  that  the  changes  1n
testes occur prior to  changes  1n  brain.  However, with  the  exception  of  one
study on  rabbits  (Chandra  et al.,  1973a),  reproductive performance was  not
tested.   These  results,  however,  were obtained  using  parenteral routes  of
exposure, thus being  of  limited  value 1n predicting reproductive  hazards  of
Ingested or Inhaled manganese.
    The  few  remaining studies are  not 1n agreement  with the  Chandra  stud-
ies.   They  show  that manganese  1s  not  likely  to  Influence  reproductive
parameters.  The  most  accurate studies  describing long-term dietary  exposure
to manganese show that dietary levels  up  to  1004 ppm (Jarvlnen and Ahlstrom,
1975)  as  MnSO »7H  0 and  up  to   3550  ppm   (Laskey   et   al.,   1982)   as
Mn 0.  were  almost   without  effect  on  reproductive  performance.   However,
  O T"
some  observations 1n  all  these  studies  need  to be  verified using  well-
defined reproductive testing protocols.
6.5.   HEMATOLOGIC EFFECTS
6.5.1.   Human  Studies.    Reports  about  the  effect  of  manganese  on  human
blood and hemoglobin  show  conflicting results.   The  studies are difficult to
compare  because  of  variations  1n exposure  and  stage of  disease  or effect.
Keslc and  Hausler  (1954)  reviewed  these data and suggested that many authors
had not  considered the variability 1n normal Individuals.
    Keslc  and  Hausler  (1954)  reported  hematologlcal  data  comparing  52
exposed  miners  without symptoms  of  poisoning  to  60  sawmill  workers of sim-
ilar  age and  social  conditions.   The miners  had higher mean  levels of eryth-
rocytes,   4.5x10"   compared  to   4.3x10" .    Mean  hemoglobin  levels  were
higher  1n miners, 15.03 compared  to 14.19 g,  and mean monocyte levels were
lower  (6.4 vs. 7.8%).
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    In a study on  Industrial  manganese poisoning, FUnn et  al.  (1941)  found
a low  white  cell  count 1n a  group  of  23 workers exposed  to  manganese.   The
average white  cell  count was  5380  for the workers  as  compared to  7850  and
7560  for  the two  control groups.   Seven  of  the  11  affected men had  a  white
cell  count  <5000  and, of  these,  three men had  a count <4000.  In  general,
leucopenla became more pronounced with the progress  of the disease.
    Chandra et al.  (1974)  reported  lower  erythrocyte  counts  (RBCs)  and  lower
hemoglobin concentrations  1n  12 cases diagnosed  as  manganese  poisoning com-
pared  to  20 controls.  Both  cases  and controls  were  under  age 38;  3  cases
were  mild,   8  moderate,  and   1  severe  according  to  the  system  of  Rodler
                                                   e   o
(1955).   The  RBC   levels  ranged from 3.5-4.8x10" /mm ,  and  controls  from
5.0-5.6xlO~6/mm3.    Hemoglobin  levels  for  cases  and  controls were  11-14.5
g/100  m&   and 15-17  g/100   mi,  respectively.   Total  white  blood   cell
                                  3
counts  ranged  from 7000-11,000/mm  1n  both  groups  with a  normal  percentage
of white cell  forms.
    Paternl  (1954)  claimed that small  doses  of  manganese had  a  stimulatory
effect  on erythropolesls.  From other  findings  encountered 1n chronic manga-
nese  poisoning,   1t  was  presumed  that   large  amounts  of manganese  caused
depression  of  both  erythropolesls and granulocyte formation (Cotzlas, 1958).
Rodler  (1955)  also  reported  a change  1n  white-cell  count  1n 52% of patients
with  manganlsm,  with  a  relative Increase  of  lymphocytes and  a decrease 1n
the  number  of  polymorphonuclear cells.   Details  and a comparison  group  are
lacking.
6.5.2.   Animal  Studies.   Animal  studies  have  confirmed  some of  the  ob-
served  hematologlcal  effects   1n humans.   For  example, Baxter  et  al.  (1965)
found  that   hematocrlt and mean corpuscular  volume were  significantly  In-
creased  1n  rats  receiving 150 mg  Mn/kg  bw  subcutaneously,  while  serum cal-
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dum and  Iron were markedly  depressed.   Blood  volume was  unchanged;  serum


magnesium,  chloride,  and phosphorus  showed significant  Increases.   Similar


findings  were  reported  by  Oo1  (1959),  who  exposed  rabbits  to  MnO   1n



specially  designed  Inhalation chambers.   Both  erythrocyte  count  and  hemo-


globin content  tended  to Increase.   The leukocyte count  changed more exten-


sively with a relative  Increase of  lymphocytes.   Matrone et  al.  (1959)  found



that  2000 ppm  of  manganese  1n  the diet  depressed  hemoglobin formation  1n



both rabbits and baby pigs.  They estimated that the minimal level of manga-


nese  1n  the diet  that  Interfered with  hemoglobin formation was  between  50


and  125   ppm.   Similarly, Hartman  et al.  (1955)  showed that  2000 ppm  of


manganese 1n the diet Interfered with hemoglobin regeneration 1n lambs.


    Carter  et  al.  (1980)  exposed   two  groups  of Long-Evans  rats   to  four


levels  of manganese as  Mn  0   at 50 ppm  (normal  dietary level),  400,  1100
                           O T"

and  3550  ppm.   One group was  maintained on a  normal  diet,   the other  on  an


Iron-deficient  diet.    After   exposure  to  Mn  0  during  the  prenatal  and
                                               O *r

postnatal  period,  no  changes   In  red blood cell  count,  mean cell  volume,  or



hematocrlt  were related  to manganese  dose  1n  the  normal   low-Iron  group.


Young  animals,  24-100  days of age, on  low-Iron  diets  developed  mlcrocytlc


anemia related  to manganese dose.


6.5.3.    Summary.   Reports  of hematologlcal  effects  are  conflicting,  but


Increased  hemoglobin values and erythrocyte counts have been associated with


human  (Keslc  and Hausler, 1954)  and animal (Baxter  et  al., 1965) exposures


to  high   levels  of  manganese.   Young  animals  maintained  on  a  low-Iron diet



and  receiving  manganese treatment during the  prenatal  and postnatal periods


may develop a mlcrocystlc anemia (Carter et al.,  1980).
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6.6.   CARDIOVASCULAR SYSTEM EFFECTS
6.6.1.   Human Studies.   Sarlc and  Hrustlc  (1975)  measured blood  pressure
1n  three  groups  of workers aged  20-59  to observe the effect of  exposure  to
airborne  manganese.   The  dlastoUc  and  systolic  blood  pressure  of  367
exposed workers  from  a  ferromanganese plant were compared  to  189 workers  1n
electrode  production  within the  same plant  not  directly exposed  to  manga-
nese,  and  203  workers   1n  a  light metal  plant  unexposed  to  manganese.
Seventy-five  percent  of  exposed  workers  had  been exposed  for  more  than  4
years.  The  mean concentration of  manganese for  work sites with  manganese
                                    3
alloy  varied  from  0.39-20.44  mg/m .   At sites  for  electrode  production,
                                              3
the concentrations varied from 0.002-0.30 mg/m .
    Workers  1n the  manganese  alloy  plant  had the  lowest  mean  systolic blood
pressure  (130.8)  followed by electrode  plant  workers  (133.6)  and  the light
metal  plant  workers   (138.7).   The  same  trend  occurred  1n  each  of  four
10-year age  groups  and  1n  all  workers  excluding hypertensives.   The  lowest
mean  dlastoUc pressure  was 1n  workers  In the light  metal plant,  followed by
the manganese  alloy plant workers  and  then those from  the  electrode  plant.
This  was  observed  also  for  each age group except  the  oldest and  was  also
seen  when  hypertensives  were excluded.   All  of  the  comparisons  were signifi-
cant  at  the 0.05 or  0.01  level,  but since multiple  t-tests were performed,
this  should  be Interpreted with  caution.   It has to  be  noted  that although
the  mean   body  weight  1n  the  compared  groups  did  not  differ,  a  detailed
analysis  of  the  body bulk  1n  relation  to the blood pressure values was  not
performed.   As stated  by the  authors, other  risk  factors  also may have been
Insufficiently controlled.  Sarlc (1978)  suggests  that the differences found
1n  the  behavior  of  systolic  and dlastoUc  blood pressure  1n  those occupa-
tional ly  exposed  to manganese  may  Indicate  an  action of manganese Ions  on
the myocardium.

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6.6.2.   Animal Studies.   In  rats,  Klmura et  al.  (1978) found  that  dietary
exposure to  564  ppm manganese produced  a significant Increase  1n  the  level
of blood  serotonin and  a  decrease In  blood  pressure.  The  researchers  at-
tributed the final marked  decrease of  blood pressure  to  the elevated  concen-
tration of serotonin 1n the blood, probably released from different tissues.
6.6.3.   Summary.    Manganese  exposure  has elicited   decreases  1n  systolic
blood pressure 1n  humans (Sarlc and Hrustlc,  1975)  and 1n  animals  (Klmura et
al.,   1978).  This  latter finding was  attributed  to  the elevated  concentra-
tion  of serotonin 1n the blood.
6.7.    BIOCHEMICAL EFFECTS
6.7.1.   Human  Studies.    Rodler  (1955)  reported  diminished  excretion   of
!7-ketostero1ds 1n 81%  of  the patients with chronic  manganese  poisoning  and
an Increase  1n basal  metabolism  1n  57% of the cases  with  manganlsm.   These
conclusions are reported with  no  supporting data.
    Jonderko et al. (1971) compared a  group of manganese-exposed workers  who
did not exhibit symptoms or signs of  Intoxication  with a control group  of 45
workers.  The  exposed workers had lower  levels of  magnesium,  hemoglobin,  and
reduced glutathlone,  while calcium  and  cholesterol  levels  were  Increased.
In an  evaluation  of  the effects  of manganese  exposure on  the development of
atherosclerosis,  several  variables were  compared between  110  workers  1n  a
steel mill and 80  nonexposed  controls  (Jonderko et  al.,  1973).   Workers were
exposed for  an average of 9  years  to  values  of  manganese that were  1.3-50
times  above  the  maximum allowable concentration.   The English  abstract pub-
lished  with  this  study reported  statistically  significant  Increases  1n mean
cholesterol,  3-l1poprote1ns   and  total  Upoprotelns,  as  well   as  Increased
Incidences  of  hypertension and atherosclerosis 1n the  exposed  group.   How-
ever,  there  1s no  stratification  or  other control  for  confounding variables


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such as  smoking  or  obesity.  The  Information  available from  table  headings
and  the  abstract did  not  describe exposure  levels  or age  distribution  and
the statistical test was not named 1n English.
    Jonderko et  al.  (1974)  also examined a group of  34 Iron-manganese plant
workers  during  employment  and  2-4 years  after cessation  of  occupational
exposure.  When  compared with a  group  of  45  control  subjects,  Jonderko found
slight changes with a  tendency  to  normalization after exposure  ceased  1n  a
number of  biochemical  parameters,  Including lactate  dehydrogenase,  alanlne
and asparaglne amlnotransferase,  cholesterol,  and glutathlone  levels.   Hemo-
globin concentration  1n  the followed workers also Increased  from 12.6  during
employment to 13.9  1n the follow-up.
    In a clinical  and  biochemical  study  conducted  1n  12  cases  of suspected
manganese poisoning,  Chandra et  al.  (1974)  reported  a statistically signifi-
cant  Increase  1n serum calcium and adenoslne  deamlnase levels  1n  cases  of
mild and moderate  grades of poisoning, and  particularly  1n  a  case of  severe
poisoning,  compared  with  values  In  normal volunteers.   They  suggest  that
serum  calcium  levels  be  used  to  delect  manyanese  poisoning 1n  the early
stages.
6.7.2.   Animal  Studies.   Intratracheal  administration  of  400   mg  Mn02/kg
bw  to  rats  caused  a  significant  decrease  1n  the  levels of  serum alkaline
phosphatase  and  Inorganic  phosphate,  and an Increase  1n  calcium (Chandra et
al.,  1973b).   Similar  observations  were  reported  by  Jonderko (1965).  Rab-
bits  Injected  Intramuscularly  with 3.5  mg  Mn/kg bw showed  a  distinct  In-
crease of  serum calcium and  a  decrease  of Inorganic  phosphorus.  However,
the mechanism  of hypercalcaemla and hypophosphataemla  1n manganese toxldty
was not  clear  because no gross  or  microscopic  abnormalities  were observed 1n
parathyroids and bones of exposed rats (Chandra et al., 1973b).


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    Chandra and Imam (1975) studied the effect  of  Intravenously  administered
2.5  mg MnCl  /kg  bw  on  the   rabbit  adrenal  cortex.   An  Increase  1n  the
cholesterol content and  marked degenerative changes  1n  the zona glomeruloza
and zona fasdculata were observed after a  period  of  2  months.   Three  months
after  the  beginning of  exposure,  the  damaging effect  of  manganese on  the
adrenal cortex was even more marked.
6.7.3.   Summary.   Effects  of  manganese exposure  on  the biochemical param-
eters  Include an  Increase  1n  serum  calcium,  adenoslne deamlnase,  choles-
terol,  total  I1p1ds and 3-Hpoprote1ns  1n  workers  occupatlonally  exposed
to manganese  (Jonderko et  al.,  1974).   A  diminished excretion  of  17-keto-
sterolds has  been  reported 1n  patients  with  chronic   manganese  poisoning.
Animal  experiments  demonstrate a decrease  1n  the  levels  of  serum  alkaline
phosphatase and Inorganic phosphate, and an  Increase  1n  calcium  1n manganese
toxldty (Chandra et al., 1973b).
6.8.   DIGESTIVE SYSTEM EFFECTS
6.8.1.   Gastrointestinal  Tract  Effects.    The  paucity  of   data  and  the
controversy regarding  the  doses used  In  the  available studies  cause  great
difficulty  1n assessing  toxic effects  of  manganese on the  GI  tract.   For
example,  Chandra and  Imam (1973)  described  significant  hlstochemlcal  and
hlstologlcal  alterations  1n the GI mucosa  of guinea pigs exposed orally to
=4.4  mg Mn/kg  bw for  a period of  30 days.   However, an amount of  =4 mg
Mn/kg  bw has  been recommended  by the  NAS  (1973) as a minimum requirement for
guinea  pigs.   Even  though  no  specific  effort was  directed to  determine the
minimum manganese dally  requirements,  Everson et  al. (1959)  reported  a diet
to  be  adequate  with the presence of 40 ppm manganese.   Further, Shrader and
Everson  (1968)  reported  that  manganese   supplementation  (125  ppm   for  2
months)  completely  reversed  the  reduced  glucose  utilization  caused  by
congenital manganese deficiency.

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6.8.2.   Liver Effects.   The liver  plays  a  significant role  1n manganese
metabolism, and  the  biliary  route  1s very Important for the removal  of  man-
ganese from  the  body.   Over 99% of  an  Intravenous  dose excreted by  the  rat
appeared  1n   the  feces  (Klaassen,  1974).   However,  manganese  has  produced
1ntrahepat1c  cholestasls  1n rats, with  large  doses causing both  functional
and morphological alterations (WHzleben et al.,  1968;  WHzleben,  1972).   An
Intravenous  dose of  55-60  mg/kg  bw manganese  caused  necrosis  1n rat  liver
and other  ultrastructural alterations resembling  some of those  seen  1n  human
cholestasls  Induced  by drugs  (WHzleben, 1969).   When manganese overload  was
followed  by  Infusion   of  b1!1rub1n,  the  lesions  were  even   more  severe
(WHzleben,  1971,  1972),  depending  upon the  dose  of  bH1rub1n  (Boyce  and
WHzleben, 1973).
    Klaassen  (1974)  reported that  no alteration  1n  the  bile  flow  was  ob-
served  1n  rats  even at the  relatively  high  Intravenous dose of  10  mg  Mn/kg
bw.   However, when  blUrubln  was administered  Immediately after  manganese
Injection,  there was  an  almost  complete cessation  of bile  flow,   even  at
small  doses  of  manganese (3 mg  Mn/kg)  which are not cholestatlc  when  given
alone.   The  researcher  suggested the possibility  that  blUrubln may form a
chelate with manganese which precipitates and obstructs  the biliary tree.
    De Lamlrande  and Plaa (1978,  1979a,b)  showed In a  series  of experiments
on rats  that  both manganese  and  blUrubln are  essential for the Induction of
cholestasls.   Small  noncholestatic  doses of  each resulted  1n  cholestasls
when  given  together,  but  the  order and  time  of  Injection were  critical.
These  observations   suggest  that  the  manganese-b1l1rub1n   Interaction  might
depend on  the presence of short-lived Intermediate  compounds  during  the pro-
cess of manganese biliary excretion.
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    In an  attempt  to  study  the ultrastructural  changes  1n the  liver  using
doses  known  to  be  nontoxlc,  Wassermann  and  Wassermann   (1977)  gave  rats
drinking water with  an extra dosage  of  200 ppm  MnCl  .  The  ultrastructural
changes  found  were  an  Increased amount  of rough  endoplasmlc retlculum,  a
proliferated smooth  endoplasmlc retlculum,  prominent  Golgl apparatuses  and
the occurrence of  multiple  rough endoplasmlc dsternae, which may  be  Inter-
preted as an adaptation process  to Increased exposure to MnCl  .
    Various biochemical  or  hlstologlcal  changes  1n  the liver were  reported
1n a  number of  studies, mainly  as  side  effects 1n  the   experiments  where
neurological,  respiratory,  or  reproductive effects of  manganese  were  Inves-
tigated.   Chandra  and  Tandon (1973)  and  Shukla et al.  (1978)  reported some
biochemical and  hlstopathologlcal  alterations  1n the  livers  of rats  given
orally 2.8  or  4.4  mg Mn/kg  bw.   However,  as was stressed  earlier  (see Sec-
tion 4.3.2.3.),  the  administered doses were  too low  to be considered  toxic
to rats.   Thus,  the  rats  on  manganese-supplemented diets  (564  ppm manganese)
did not manifest abnormalities  1n the liver,  and the liver  monoamlne oxldase
activity  remained  the  same  as  1n  the control  group  of  animals  (Klmura  et
al., 1978).
    Parenteral  administration of  manganese sulfate  1n  a  dose of 6  mg  Mn/kg
bw did not  significantly affect the  enzyme activity  1n the liver of exposed
rats,  1n spite  of a  significant  accumulation  of  this metal  1n  the  liver
(Singh et al., 1974, 1975).  Only the activity of succlnlc  dehydrogenase and
lactate  dehydrogenase  decreased  to a considerable  extent.   Some  pathomor-
phologlcal alterations  were observed  1n  the  liver  of the  treated  animals,
where  some of   the  sections showed  mild  congestion   of  central veins  and
adjacent  sinusoids.  Minute areas of  focal necrosis  were  noticed throughout
the section.
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    Microscopic examination  of  the liver In monkeys  exposed  parenterally to
relatively  high  doses  of  manganese  showed  only mild  changes.   In  monkeys
receiving 345  mg  Mn/kg  bw,  Pentschew et al.  (1963)  found only hemoslderosis
of  the  Kupffer cells.   Neff et  al. (1969)  described  only  variable,  often
mild,  vacuolar changes  1n   the  liver  cells  of  the monkeys  subcutaneously
Injected with  500  mg  Mn/kg  bw.   Finally, Suzuki  et  al.  (1975) reported that
an  Irregular  arrangement of  hepatic cords  and  lymphocytlc  Infiltration of
GUsson's capsules  were  seen  1n  two monkeys  receiving  the  highest  doses,
totaling 5680 mg Mn/kg bw over a period of 9 consecutive weeks.
6.8.3.   Summary.   The  lack of data  and  the controversy over  the  doses  used
1n the available  studies  cause difficulty  1n  assessing  toxic  effects  of man-
ganese on  the  Intestine.  On the  other hand, more  data  are  available about
the hepatotoxlc effects  of manganese.   The  liver  plays  a  significant  role 1n
manganese  metabolism,  and   the  biliary  route  1s   very   Important  for  the
removal  of  manganese  from  the  body.  Over 99% of  the Intravenous dose was
excreted by  the rat  1n  the feces.   Manganese  has been  described  as an agent
that  produces  Intrahepatlc  cholestasls, large  doses  causing  both functional
and morphological  alterations.   An  Intravenous dose  of manganese at  a con-
centration  of  55-60  mg/kg  bw of  the rat caused necrosis 1n  the  liver and
other  ultrastructural  alterations  resembling  some  of those  seen 1n  human
cholestasls  Induced by  drugs (WHzleben, 1969).  Microscopic  examination of
the liver 1n monkeys  exposed  parenterally  to  relatively high  doses of manga-
nese  showed  only   mild  changes,  for  example,  hemoslderosis  of  the  Kupffer
cells.
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                             7.  CARCINOGENICITY
7.1.   ANIMAL STUDIES
    Manganese  sulfate  1n  sodium chloride  has  been  tested  for carcinogenic
activity  1n  the Strain A mouse  lung  tumor  system (Stoner et al., 1976).   In
this  study,  Strain  A/Strong  mice of both sexes, 6-8 weeks old, were Injected
1ntraper1toneally  3  times/week  for a  total  of  22  Injections.   Three dose
levels  were  employed  that  represented the  maximum  tolerated  dose,   a 1:2
dilution  and  a  1:5  dilution  of the maximum tolerated dose.  Twenty mice were
used  at   each  dose   level  (10/sex)  Including  vehicle  (saline) and  positive
(urethan)  controls.   Mice were  sacrificed  30  weeks  after  the  first   Injec-
tion,  and the frequency of  lung  tumors  1n  each test group was statistically
compared  with that 1n the vehicle-treated controls using  the student t  test.
    The Interpretation  of  the  lung  tumor data 1n the Strain A mouse 1s  some-
what  unusual  1n that certain  specific  criteria should be met  before  a com-
pound  1s  considered  positive (Sh1mk1n and Stoner, 1975):
    1.  A  significant  Increase  1n  the  mean  number  of  lung  tumors  1n
        test animals, preferably >l/mouse, should be obtained;
    2.  A dose-response relationship should be evident.
    3.  The mean number of  lung  tumors  1n  control  mice  should  be con-
        sistent  with the  anticipated  Incidence  of  spontaneous  tumors
        for untreated strain A mice.
The results  obtained by  Stoner  et al.  (1976)  are  summarized  1n  Table 7-1.
These  data  Indicate  that  the  above criteria  were  not conclusively met for
the establishment of a positive  response.   A slight  but  statistically sig-
nificant  Increase 1n the  number  of pulmonary adenomas  per  mouse  was  associ-
ated with  administration  of  the  high  dose.   The response was  somewhat ele-
vated  at  the  other   doses, but was  not  statistically  significant.   Overall,
H can  be concluded  that  the  results  of  this  experiment are  suggestive  of
carcinogenic activity.

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                                                       TABLE 7-1
10
ig Pulmonary Tumors 1n Strain A Mice Treated with Manganese Sul
fate3

Total Dose
Group
Untreated control
Solvent control
(0.85X NaCl)
Treated
^ Treated
Treated
20 mg urethan6
mg MnS04/kg
0
0

132
330
660
0
mg Mn/kg
0
0

42.9
107.2
214.4
0
Mortality
1/20
1/20

1/20
0/20
2/20
2/20
Mice with
Lung Tumors (54)
6/19
7/19

7/19
7/20
12/18
18/18
(31)
(37)

(37)
(35)
(67)
(TOO)
Average Number
Tumors/Mouse^
0.28+0.07
0.42+0.10

0.47+0.11
0.65+0.15
1 . 20+0 . 49
21.6+2.81
PC
NA
NA

NS
NS
0.05d
NR
PO
oo
CO
CO
aSource: Stoner et al., 1976
bX+S.E.
^Student t test
dF1sher Exact Test p = 0.068
eS1ngle 1ntraper1toneal Injection
NA = Not applicable; NS = Not significant; NR = Not reported

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     DIPaolo  (1964)  Injected  DBA/1  mice  subcutaneously  or  IntraperHoneally
wHh  0.1  ml of  a  154 MnCl~  aqueous  solution  twice weekly  for  6  months.
Control  mice were Injected with water.   Mice  were sacrificed as they became
moribund  or  at  18 months  of  age.   Sixty-seven percent  (24/36)  and  41%
(16/39)  of  the  mice  treated  subcutaneously  and  1ntraper1toneally,  respec-
tively,  had  lymphosarcomas;  the   Incidence  1n  controls  was  24%  (16/66).
Tumors appeared  earlier  1n the treated groups  than 1n the control  group, but
statistically  significant differences 1n the  number of  other tumors (e.g.,
mammary  adenocarclnomas,   leukemlas,  Injection site  tumors)  did  not occur.
The  results  of  this study were published  1n abstract  form,  and  additional
details  regarding experimental  design  or  results  were not given.   Therefore,
a  thorough evaluation  of  the results 1s not  possible.
     Furst  (1978)  evaluated  the  carclnogenldty  of manganese powder  and
MnO_  1n  F344 rats  and Swiss mice, and manganese (II)  acetylacetonate (MAA)
1n  F344  rats.   The  test  materials  were suspended 1n trloctanoln, and admin-
istered  Intramuscularly  (1.m.) or   by  gavage as  follows.   Groups  of  25 rats
of  each  sex  were administered  10 mg manganese  (1.m.) per month for 9 months,
10  mg  Mn02 (1.m.) per  month for 9  months, 50  mg  MAA (1.m.)  per month for 6
months,  or  10 mg  manganese  (gavage)  twice  per month for  12 months.   Groups
of  25  female mice were administered single  10 mg doses  of manganese powder,
6  doses  of  3 mg  MnO_,   or  6  doses of   5 mg  MnO   via  1.m.  Injection,  but
the  frequencies  of  Injection  In  these  experiments were  not stated.   Complete
necropsies  were   performed  on all  animals  and  obvious   growths,   suspicious
tissues,  lungs and  livers  were examined h1stolog1cally.   The duration of the
experiments were  not specifically  stated, but  were  Implied  to be 2 years 1n
the  rat  experiments.  As summarized  1n  Table 7-2,  no  difference  1n  tumor
Incidence  was  noted between  treated  and control  animals  with respect  to


0199P                               7-3                              4/28/83

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                                                                              TABLE 7-2


                                         Carclnogenlctty of Manganese Powder, Manganese Dioxide and Manganese Acetylacetonate
                                                                 In F344 Rats and Swiss Albino Mice3
Compound0 Species
TrlglyceMde control rat
Manganese powder rat
Manganese acetylacetonate rat
TMglyceMde control rat
Manganese dioxide rat
Trlglycerlde control rat
Manganese powder rat
Trlglycerlde control mouse
Manganese powder mouse
Treatment
Route Schedulec
1 .m. 0.2 ml/month x
12 months
1 .m. 10 rag/month x
9 months
l.m. 50 Big/month x
6 months
l.m. 0.2 ml/month x
12 months
l.m. 10 ing/month x
9 months
oral 0.5 ml, twice
monthly x 12
months
oral 10 rog, twice
monthly x 12 months
l.m. 0.2 ml/Injection x
3 Injections
1 .m. 10 mg (single
Injection)
Total
Dose Tumor Type
2.4 mi lymphomas/leukemla
f Ibrosarcomasd
90 mg lymphomas/leukemla
Mbrosarcomas
300 mg lymphomas/leukemla
flbrosarcomas
other sarcomas
2.4 ml lymphomas/leukemla
flbrosarcomas
90 mg lymphomas/leukemla
flbrosarcomas
12.5 ml lymphomas/leukemla
flbrosarcomas
240 mg lymphomas/leukemla
flbrosarcomas
0.6 mi leukemia
lymphomas
10 mg leukemia
lymphomas
Incidence
(males) (females)
1/25
1/25
3/25
3/25
2/25
13/25e
3/259
0/25
0/25
0/25
0/25
3/25
0/25
0/25
0/25
NT
NT
NT
NT
3/25
1/25
5/25
0/25
2/25
6/25f
4/25
0/25
3/25
0/25
3/25
0/25
0/25
0/25
2/25
1/25
6/25
1/25
IV)
oo
GO

CO

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                                                                            Table 7-2 (cont.)
1C
-o
Treatment Total
Compound" Species Route Schedule0 Dose
Tr1glycer1de control mouse 1.m. 0.2 ml/Injection x 24 ml
12 Injections"
Manganese dioxide mouse l.m. 3 mg/1nject1on x 15 mg
6 injections"
Manganese dioxide mouse l.m. 5 mg/lnjectlon x 30 mg
6 Injections"
Incidence
Tumor Type
leukemia
lymphomas
leukemia
lymphomas
leukemia
lymphomas
(males)
NT
NT
NT
NT
NT
NT
(females)
2/25
0/25
4/25
1/25
1/25
2/25
 I
in
aSource: Furst. 1978
bCompounds suspended 1n 0.2 ml (l.m.) or 0.05 ml (gavage) trloctanoln
C0urat1on of  experiments  was not stated, but was  Implied  to be 2 years  In  the rat studies.  The  average weights of the  treated  and  control
 mice ranged from 22-25 g at the start of the experiments to 33-39  g  at  the end  of  the  experiments.
^Injection site Hbrosarcoma
eF1sher Exact Test p = 0.002
fF1sher Exact Test p = 0.049
Slncldence Includes 2 rhabdomyosarcomas and  1 myxosarcoma
"Intervals between Injections not stated
NT = Not tested
CD
CO
CO

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manganese  powder  and  MnOp.    In   contrast,   a   statistically  significant
number of  fIbrosarcomas  {10 tumors 1n 25 male  rats,  p = 0.002;  6  tumors  1n
25 female rats, p  =  0.049)  developed  at  the Injection site 1n the rats given
MAA as compared  to vehicle controls; the mean  latency  period was 17 months.
However,   the  results of  the  assay with  the organomanganese  compound  (MAA)
cannot necessarily  be  extrapolated  to  pure  manganese  or   other  Inorganic
manganese compounds.  Furst (1978) commmented that  MAA  suspended  well  1n the
vehicle,  and that  the carcinogenic effect may therefore be Inconsistent with
foreign-body cardnogenesls.   Further,  1t   1s doubtful  whether  these results
have any relevance to exposure to Inorganic  manganese through Inhalation.
    In June 1980,  the Executive  Committee of the  National Toxicology Program
Included manganese sulfate  1n  the  11st of priority chemicals for  testing the
toxlcologlc and  carcinogenic  effects.  Prechronlc  testing  of manganese sul-
fate  1n  Fisher 344  rats  and  B6C3F,  mice  administered via  their  feed began
during March 1982  [National Cancer Institute (NCI), 1982].
    Intraperltoneal  Injection  of  another   organomanganese  compound, methyl-
cyclopentadlenyl  manganese (MMT) (80 mg/kg), produced  cell  proliferation 1n
the  lungs  of  female A/J  mice  (WHschl et  al., 1981).   When mice (30/group)
were  treated  with single  Injections  of  urethan  (500  mg/kg) followed 1 week
later  by 6 weekly  Injections  of 80 mg/kg  MMT, lung  tumor  formation was not
enhanced  when  compared  with urethan  treated controls.   Weekly Injections of
MMT  alone did  not  Increase  the  Incidence of  spontaneously  occurring lung
tumors.
    Sunderman  et  al. (1974, 1976) also  reported  that 1.m.  administration of
manganese  did  not Induce  Injection site  tumors  1n  Fischer rats.  Single 1.m.
Injections  of  0.5  mi  of  penicillin  suspensions  containing manganese dust
 0199P                               7-6                               5/06/83

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were  admlnstered at  the  dosages specified  1n  Table 7-3,  and Incidences of
local   sarcomas  were   tabulated after   2  years.    The  results  of  other
similarly-designed  experiments   1n  these  studies Indicated  that  addition of
equlmolar  amounts  of  manganese  dust  to  nickel   subsulflde (N1~S_)  dust
significantly  depressed  N13S2-1nduced  tumor1genes1s.    Subsequent  work  by
the  same  group of  Investigators  (Sunderman  et  al.,  1980) showed that, under
the  same  experimental  conditions,  manganese dust also  Inhibited local sar-
coma  Induction by benzo(a)pyrene.
7.2.    HUMAN STUDIES
    There  are  numerous  ep1dem1olog1cal   studies  designed  to evaluate  the
chronic effects  of manganese,  such as  CNS  abnormalities  or  pneumonia,  but
none  have attempted  to  relate manganese  exposure   to  cancer mortality  or
Incidence.  To assess  the  relationship between  manganese 1n soil  and cancer,
Marjanen  (1969)  correlated  the  amount  of  soluble  manganese  1n cultivated
mineral soil   1n  199  parishes  with the  5-year  cancer   Incidence  rates from
1961-1965.   He determined  that cancer  Incidence  decreased  with Increasing
content  of  manganese;   there   was  a  statistically   significant  correlation
coefficient of  -0.66.   The data excluded  cities and were  not age-adjusted.
Further work  Is  needed to  assess  the  effect of confounding  factors  such as
age  differences  among  parishes, social  class  and  dietary habits,  type  of
cancer  contributing  to  the association,  and extent  of  consumption  of  local
foods.
    Blood   plasma  levels   of  manganese  were   reported   to  be  elevated  1n
patients with  stage  IV  bronchogenlc carcinoma (T1mask1na et  al.,  1981).   An
earlier study  (Morgan,  1972)  of  autopsy   samples  of   hepatic   tissue  from
patients who  had died  of  bronchogenlc carcinoma, with  and  without  chronic
0199P                               7-7                              4/28/83

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                                                       TABLE  7-3
10
10
-o
— J
1
ao


Dosage of
Mn Dust3
0 mg/rat
2.1 mg/ratb
0 mg/rat
0.5 mg/ratc
1 .0 mg/ratc
2.0 mg/ratc
4.0 mg/ratc
4.4 mg/ratd
4.4 mg/ratd
Induction of Sarcomas
Number of
2-yr Survivors
16/24
17/24
22/60
6/15
2/15
8/15
10/15
NR
NR
1n Rats by the Intramuscular Injection of Manganese Dust
No. of Rats with Injection Site
Sarcomas/Total Number of Rats Reference
0/24 Sunderman et al. ,
0/24
0/60 Sunderman et al. ,
0/15
0/15
0/15
0/15
0/20 Sunderman et al.,
0/20


1974
1976
1980
r«o
co
oo
aF1scher  rats  were  given a  single  1.m.  Injection  of  0.5  m8,  of  penicillin  suspension containing  the
 manganese dust.

bMean  particle  diameter,  1.4  vm.   Manganese  dust  was  composed  of  62%  elemental  Mn,  36%  manganese
 oxides (as Mn02), <0.1%N1,  Cu, Cr, and  Co,  2% Al.

cMean  particle  diameter  1.6  urn.   Manganese  dust  was  composed  of  94% elemental  Mn;  6% 02; <0.02%  Al,
 Co, Cu, and N1; 0.01% Cr.

dThe results of two 2-year experiments were reported 1n an  abstract,  but control  data were not  reported.

NR = Not reported

-------
bronchitis  and  emphysema,  reported  slightly  elevated  hepatic manganese con-
centrations  1n  patients  with emphysema and carcinoma  (p  = 0.05), but not 1n
patients with emphysema and  bronchitis alone or lung carcinoma alone.
    Malignant   breast  tissue  concentrates  contained  significantly  higher
amounts  of  copper,  magnesium,  zinc,  and manganese  than  did   noncancerous
breast  tissue   (Mulay  et  al.,  1971).   However,  a  subsequent  study measured
trace  metals 1n  cancerous  and  noncancerous  breast  tissue  and  found  only
magnesium  and  zinc  levels  to be elevated  (Santol1qu1do  et al.,   1976).  Man-
ganese  was found to be  elevated 1n  osteogenlc  sarcoma  tissue when compared
to normal  specimens (Leach,  1971; Jones et al., 1972).
    The remainder of the studies pertaining  to manganese levels   1n cancerous
tissue  relate   to manganese-superoxide  dlsmutase.   Superoxlde 1s an anlonlc
free radical and an active reducing agent.  Superoxlde dlsmutases (SOD) con-
vert  superoxide to H^O-,  which 1n  turn   1s  converted  to water  by catalase
and peroxldase  (Fee, 1980).  Two types  of  SOD are found 1n eukaryotlc cells:
Zn/Cu SOD  1n the cytoplasm and  Mn  SOD within mitochondria (Sun et al., 1980;
Oberly  and  Buettner,  1979).   Mn SOD  1s generally  reduced  or absent 1n tumor
mitochondria, Including mouse neuroblastoma  cells  (Oberly  et al., 1978),  rat
Morris  hepatoma (B1ze and Oberly,  1979;  B1ze et  al.,  1980),  rat hepatoma
HC-252  (Sun  et  al.,  1980), and  human  lymphoma  lymphocytes  (Issels and Leng-
felder, 1981).   Other  human tumors  (Westman  and Marklund,  1981)  and  chemi-
cally-Induced rat  colon  adenocardnoma (Loven  et al., 1980), however,  were
not found to have decreased levels  of Mn SOD.
    Diminished   Mn SOD  1s  correlated with  Increased  production of superoxide
radicals;   manganese  has  been  suggested as  a dietary  supplement  1n  cancer
treatment,  particularly for  protection  against  the  extra  superoxide produced
by activated macrophages   Involved  1n antHumor  Immunity (McCarty,  1981).


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Reduced levels  of  Mn SOD have  been  hypothesized  to prevent  differentiation
of cancer  cells  due to  Increased  superoxlde,  and  addition of SOD to  trans-
formed cells seems  to  overcome  some  of the blockage of cell  differentiation
(Oberly et al., 1980).
7.3.    SUMMARY
    Prior  to the adoption of the International Agency for  Research on  Cancer
(IARC) criteria, the U.S.  EPA  Carcinogen  Assessment Group (U.S. EPA,  1979c)
judged manganese  to be  a  possible human  carcinogen  based on the mutagenlc
properties and  the  positive  responses  1n  mice Injected 1.p.  {DIPaolo,  1964)
and 1n rats  (Furst, 1978).  However,  1n  the  summary  (U.S. EPA, 1979)  1t  1s
stated that the pathology was Incomplete  and  that  there were  no  animal  stud-
ies with  long-term exposure by  feeding  or  by Inhalation.
    Therefore,   using  IARC  criteria,   the available evidence for manganese
cardnogenlcUy would be rated as  Inadequate  1n animals (IARC,  1982).   Since
no data are available  for humans,  manganese would  be  placed  1n  IARC  Group  3:
which states  the  chemical  or group  of chemicals  cannot be classified  as  to
Us carc1nogen1c1ty for  humans.  More  Information  1s needed before a conclu-
sion can  be made about  carc1nogen1c1ty  of  manganese or  Us  compounds.
0199P                               7-10                             5/06/83

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                     8.   MUTAGENICITY AND TERATOGENICITY
8.1.   MUTAGENICITY
8.1.1.   Tests for  Gene  Mutations.   Mutagenldty of  manganese salts  toward
bacteria was  first  described  by Demerec and Hanson 1n  1951.   A strain of E_.
coll  dependent  on  streptomycin for  Us  growth  was  treated  with MnCl   1n
suspension culture  and  then replated  1n  the absence  of  the drug,  to select
for  mutations from  streptomycin  dependence to  nondependence.  The  results
showed  that   the  mutagenlc  potency  varied  depending  on  the  physiological
state  of  the organisms.   Similar  experiments with  Salmonella also showed
manganese  to be  mutagenlc,  although  no  details of  methods  or results  are
described {Flessel, 1977).
    M1yak1  et  al.  (1979)  found   that  MnCl_  Increased   the  frequency  of
8-azaguan1ne  resistant   Chinese hamster  cells  (due  to  a mutation   at  the
HGPRTase locus) from 2-  to 5-fold.
8.1.2.   Tests  for  Chromosomal Damage.   MnCl-  caused  chromosomal  aberra-
tions  1n 5%  of  C3H mouse mammary  carcinoma cells when  tested at a concentra-
tion  of  10"3 M  (Umeda  and  N1sh1mura,  1979).   At  concentrations  >10"3 M,
potassium  permanganate  caused  aberrations 1n  up  to  17%  of cells  (Including
breaks, exchanges and fragments).  MnCl_  was  too cytotoxlc to be tested at
the  levels at which potassium permanganate caused chromosomal aberrations.
    Oral  administration  of MnCl_  to  male  albino  rats  at  a level  of 50
vig/kg/day  for  180  days  did   not  Induce  chromosomal   damage  1n  the   bone
marrow or spermatogonlal cells  (Dlkshlth and Chandra,  1978).
8.1.3.   Tests  for  Other Genetic  Damage.  N1sh1oka (1975)  reported  a weakly
positive  effect  of  several manganese  compounds  1n  the  recombination (rec)
assay,  which measures  a  difference  1n  growth  Inhibition  between   Bacillus
subtnis  strains  H17  (rec*,   or   recombination-efficient) and  M45  (rec~,
0200P                               8-1                              05/06/83

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or  recombination-deficient).    MnCl2,  Mn(N03)2,  MnS04,  and Mn(CH3COOH)2  were
weakly  positive  1n  this  assay,  while  KMn04  was  negative.   More  recent
results (Kanematsu et  al.,  1980;  Kada  et al., 1980) report  negative effects
1n   the  rec   assay   for   MnJNO,^,   Mn(CH3COOH)2,    and   MnCl    (highly
toxic).   No  explanation was  advanced  for  these  contradictory results,  but
variations  1n  culture conditions,  medium  composition  or   valence  may  be
responsible.
    Orgel  and Orgel  (1965)  showed that divalent manganese 1s  also  mutagenlc
to the bacterlophage T4.  Treatment of T4-1nfected £. coll  at concentrations
       2
of  10   M  Increased  the   proportion  of  rapid  lysis  (rll)  mutants  from
<0.04% to =1X.
    Putrament  et  al.   (1973)   found   that  manganese   Induced  mutations  1n
Saccharomyces cereveslae. primarily Involving mltochondrlal  genes.   Although
manganese 1s  mutagenlc  toward  yeast   mltochondrlal  DNA,  1t  did  not  Induce
gene conversion or 1ntergen1c  recombination (Baranowska  et al., 1977).
    MnCl2 reduced colony-forming  ability  1n  HeLa  and  V79  hamster  cells;
this  cytotoxldty was   reversed  when   manganese  was  removed  (Skreb  et  al.,
1980).  Manganese has   been  found to  bind  to both  phosphates and  bases  on
polynucleotldes  (Kunkel and Loeb,  1979),  but Its role  1n  causing DNA damage
may Involve  many factors.
    It 1s well  documented that manganese  can  reduce  the fidelity  of DNA syn-
thesis  1^ vitro (Nagamlne et al.,  1978;  Hlllebrand and  Seattle,  1979;  Loeb
et al., 1979; MUdvan  et al., 1979; Kunkel  and  Loeb, 1979).   Substitution of
Mn II  for Mg  II resulted 1n Increased m1s1ncorporat1on by £.  coll  DNA poly-
merase I,  an Mg Il-actlvated enzyme.
    Manganese was  moderately  effective 1n enhancing viral  transformation of
Syrian  hamster  embryo  cells (Casto et al.,  1979).   As  was  the case with §_._
0200P                               8-2                              05/06/83

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coll,  medium composition  can  affect  mutagenlcHy of manganese  1n  CHO  cells.
When CHO  cells  were treated  1n  medium deficient 1n divalent  cations,  MnCl_
Increased  the  frequency  of  spontaneous mutations  from  5x10    mutants/cell
to lOOxlO"6, and reduced cloning efficiency by 33% (Hs1e et al., 1979).
8.2.   TERATOGENICITY
    In  animals,  manganese deficiency  during pregnancy  causes a  variety  of
developmental defects  related to decreased  formation  of  chondroltln sulfate
and delayed  otollth  calcification.   Resultant defects  Included reduced  coor-
dination,  bone  and  growth deficiencies,  reproductive difficulties, and  CMS
changes  (Oberleas  and  Caldwell, 1981;  Hurley,  1981).   The effect  of  manga-
nese excess has been studied by only a few Investigators.
    In  rodents,  excess manganese during pregnancy  affects  behavioral  param-
eters,  as  described  1n  two  recent abstracts.   Hosh1sh1ma   et  al.  (1978)
reported   that  geotaxls  performance,  but  not  Intelligence  testing,  was
Impaired  1n mice  treated  in  utero with  manganese.   In  another study, Massaro
et  al.  (1980)  exposed female  mice  from days 0  through  18  of  pregnancy with
                           3
MnOp  dust  (48.9£/.5  mg/m ,   continuous   exposure).   Litters  from  exposed
and nonexposed  mothers were  reduced to three pups  of  each  sex,  and the pups
were fostered equally  among  exposed and nonexposed mothers.   Pup  weight  and
activity  were  not different  whether  or  not they had  been  exposed in  utero.
but as  adults  exposed  pups  were deficient  1n   open-field, exploratory,  and
rotarod  (balance and  coordination)  performance.  Normal  offspring fostered
to  exposed  mothers  also  showed decreased  rotarod performance,  Indicating
that  post-partum exposure  can  also have  an  adverse  effect on  behavioral
development.  This  1s  supported  by  the effect  of  manganese  on  learning  1n
the adult  rat  (Murthy  et al.,  1981),  and  by a  study  of  the  distribution  of
54
  Mn  1n fetal,  young,  and  adult  rats.   Early  neonates and  19-day fetuses
0200P                               8-3                              05/06/83

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were more  susceptible  to manganese  than  the older groups;  manganese local-
ized to  the  liver  and  brain 1n  the  younger  groups  and  they accumulated more
manganese  per  weight than  the  older groups  {Kaur  et al.,  1980).   No fetal
abnormalities were  seen when 18-day embryos were  exposed  to  16  y.mol/200 g
maternal  weight,   but   this  1s  a  late  stage  for  detecting  developmental
defects.
8.3.   SUMMARY
    Divalent manganese  1on  has  elicited mutagenlc effects  1n  a wide variety
of m1crob1al  systems,  probably  by substitution for magnesium  1on  and Inter-
ference  with DNA  transcription  (Flessel,   1977).   Attempts  to  demonstrate
mutagenlc effects of manganese  1n  mammalian  systems  have failed to show sig-
nificant activity.
    Although data reported  1n abstracts suggest  that  excess manganese during
pregnancy  affects  behavioral parameters,  there  1s Insufficient  evidence to
define manganese as teratogenlc.
0200P                               8-4                              05/06/83

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             9.  EFFECTS OF CONCERN AND HEALTH HAZARD EVALUATION
9.1.   EXISTING GUIDELINES, RECOMMENDATIONS AND STANDARDS
9.1.1.   A1r.  In  the  United  States,  the American  Conference  of  Government-
                                                                   3
al  and  Industrial  Hyg1en1sts  (ACGIH,  1980)  has recommended 5  mg/m   as  both
the time-weighted  average  threshold  limit  value (TWA-TLV)  and  the short-term
exposure  limit  for  manganese.   This  value  1s  based  on  observations  of
poisoning  1n humans at  concentrations  near  or above  the  recommended  TLV.
The National  Institute for Occupational  Safety and  Health (NIOSH)  has  not
recommended  an occupational  criterion  for  exposure  to airborne  manganese,
and the Occupational Safety and  Health  Administration (OSHA) has  not  promul-
gated  a standard  for  manganese  exposure.   Occupational  standards  1n  some
other  countries,  as   summarized  by  the International  Labour Office  (ILO,
1980), are listed  below:
                                                        Comment
                                                     celling value
                                                     celling value
Country
Belgium
Czechoslovakia
Japan
Poland
Roumanla
Switzerland
USSR
mg Mn/mJ
5
2
6
5
0.3
1
3
5
0.3
                                                     celling value
                                                     celling value

The  World Health  Organization  (WHO,  1981)  recommends  a  criterion of  0.3
    3
mg/m  for resplrable manganese 1n occupational exposures.
9.1.2.   Water.   No  toxldty-based  criteria  or  standards  for manganese  1n
freshwater have been proposed.   The  WHO  (1970),  the U.S. PHS (1962), and the
U.S.  EPA  (1976)   recommended  a  concentration  of  0.05 mg/8,  1n  water  to


1805A                               9-1                              5/05/83

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prevent undesirable  taste  and discoloration.   In  the USSR, the  recommended
maximum  permissible  concentration  of  KMnO.   1s  0.1  mg/fc  (as  Mn).    The
recommendation Is  Intended  to prevent the  discoloration  of water by manga-
nese (Shlgan and VltvHskaya, 1971).
    For marine  waters,  the U.S. EPA  (1976)  has recommended a  criterion  for
manganese of  0.1  mg/9.  for  the protection  of  consumers of marine mollusks.
Although the  rationale  for this criterion  1s  not detailed, 1t  1s partially
based  on  the  observation  that manganese  can   bloaccumulate  by  "factors  as
high as 12,000" 1n marine mollusks.
9.2.   SUMMARY OF TOXICITY
    Manganese  1s  an essential element for  humans  and  animals.   The  concen-
tration  of  manganese  present  In  Individual   tissues,  particularly  1n  the
blood,  1s  controlled after  1ngest1on  by  homeostatlc mechanisms  and  remains
remarkably  constant  1n   spHe  of  rapid  fluctuations   1n  Intake  (Cotzlas,
1958).  The main  routes  of absorption are  the  gastrointestinal  and  respira-
tory  tracts.   Acute poisoning by manganese may  occur  1n  exceptional  circum-
stances where  large amounts of manganese compounds  are Ingested or  Inhaled.
Freshly  formed manganese oxide fumes  of  resplrable particle  size can  cause
metal  fume  fever  but are  not believed to  cause permanent  damage (Plscator,
1976).   The most  pronounced  toxic  effects  of  manganese are  a  CNS  syndrome
known  as chronic manganese  poisoning (manganlsm) and manganese pneumonltls.
    The  adverse  effect  on  the CNS  begins with  a  psychiatric disturbance
followed  by a  neurologic  phase  resembling Parkinson's  disease.  Manganlsm
has  been well  described  1n  the literature with  clinical details  for  case
clusters  (Fllnn  et al.,  1940;  Penalver,  1955;  Rodler,  1955;  Chandra et  al..
1974).   Cotzlas  (1962)   described  three  phases — a  prodromal  phase  with
Insidious   onset   Including  psychiatric   disturbances,  the  extrapyramldal


1805A                               9-2                              5/04/83

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disease with  symptoms  of awkward  speech and  loss  of skilled movement,  and
typical manganlsm with  severe rigidity, tremor,  and  Inappropriate  emotional
reactions.
    Manganlsm  has  been  reported  1n workers  1n  ore crushing  and  packing
mills,  1n  the production of  ferroalloys,  1n the use of  manganese  alloys 1n
the steel  Industry and  1n the manufacture of  dry cell  batteries  and welding
rods.   Very high concentrations  of manganese have been  found  1n  mines where
cases  of  manganlsm were  reported.   The manganese  air  concentration  1n  the
                                                                        3
Immediate  vicinity  of  rock  drilling  1n Moroccan  mines was  -450  mg/m   1n
                        3
one  mine  and  -250  mg/m   1n another  (Rodler,  1955).   In  two reports  from
Chilean mines  (Ansola et  al.,  1944a,b;  Schuler  et al.,  1957)  the  air concen-
                                                   3                        3
tratlons  of   manganese  varied from  62.5-250  mg/m  and  from 0.5-46  mg/m ,
respectively.
    In  ferromanganese factories,  neurological  and psychic disturbances Indi-
cating  manganese poisoning  have  been observed at manganese  levels  as  low as
2-5 mg/m3 of  air (Suzuki et al.,  1973a,b).
    While  manganlsm  and  Its  association  with  manganese  has   been  well
described, a  dose-response  relationship  1n man  cannot  be  evaluated because
duration  of   exposure  1s  not well  documented.   Also,   early  signs  of  the
disease were  sought  1n only  a few  studies  (Sarlc  et al., 1977;  Tanaka  and
Lleben, 1969),  and  none  of  the  reported studies  employed  a  standard cohort
design  (e.g., there was  no  follow-up  or comprehensive  characterization of
the exposed populations).
    A  high Incidence of  pneumonia and  other  respiratory ailments  has   been
reported  1n  workers  with occupational  exposure  to manganese  (Baader, 1937;
Lloyd-Oavles,  1946;  Rodler,  1955;  Sarlc,   1978)  and 1n  Inhabitants  living
around  factories  manufacturing  ferromanganese  or manganese  alloys  (Elstad,
1805A                               9-3                              5/09/83

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1939; Suzuki, 1970).  The  Increased  Incidence of pulmonary disease found  1n
exposure  to  low  concentrations  of  manganese  1s  not  necessarily directly
attributable to manganese  Itself.  Manganese  exposure may  Increase  suscepti-
bility  to  pneumonia or other  acute  respiratory  diseases  by disturbing  the
normal mechanism  of lung  clearance.   Some Investigators have suggested  that
long-term exposure  to manganese may contribute  to  the development  of  chronic
lung  disease  (Sarlc and  Luc1c-Pala1c,  1977),  but there  1s  Uttle data  to
demonstrate this conclusively,  particularly at ambient  levels.
    Effects  on  the  cardiovascular   system  Include   reports   of   decreased
systolic  blood  pressure   1n  humans  occupatlonally exposed  via  Inhalation
(Sarlc and Hrustlc, 1975).  This  symptom  was  also shown to occur experiment-
ally  1n  orally  exposed  rats  (Klmura  et  al.,  1978).   Reports  about  the
effects of manganese  on  human  blood and  hemoglobin show  conflicting  results
that  have not been  resolved by  animal  studies.   The studies are difficult to
compare because of  variations 1n exposure and 1n the severity of the effect.
    There have  been reports of  Impotence 1n a  majority  of workers affected
by  manganese  (Chandra  et  al.,  1974;  Emara  et  al.,   1971;  Rodler,  1955;
Penalver,  1955).   There  1s  some  experimental  evidence  of  reproductive
effects  1n  laboratory animals.   Degenerative changes  1n  the testes  of  rats
have  been produced  by excessive levels  of manganese administered by multiple
1ntraper1toneal  Injections  (Chandra,  1971;  Singh et al.,  1974,  1975;  Chandra
et  al.,  1975;   Tandon et  al.,  1975;  Shukla and  Chandra,  1977)  and by single
Intratracheal   Injections  In   rabbits  (Chandra  et  al.,  1973a).   Chronic
dietary  exposure  to  manganese  has  caused  decreased   organ  weight  for  the
preputlal gland,  seminal  vesicle  and  testls  In mice (Gray and Laskey, 1980),
and  decreased  serum testosterone levels  and  reduced  pregnancy  percentage  1n
rats  (Laskey et al., 1982).


1805A                              9-4                              5/05/83

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    Manganese dlchlorlde  Increased  the Incidence of  lymphosarcomas  1n  DBA/1
mice following twice weekly  subcutaneous  or  1ntraper1toneal  Injections  for  6
months (OlPaolo,  1964),  and  elicited slightly elevated tumor  Incidence  1n  a
Strain A mouse lung  tumor  bloassay  (Stoner  et al.,  1976).   Single or repeat-
ed  Intramuscular  Injections  of  MnO  or  manganese  powder  did not  result  1n
Increased  Incidences  of  lymphosarcomas,  leukemlas   or   local  sarcomas  1n
either sex of F344 rats  or female  Swiss mice.  However,  repeated Intramuscu-
lar  Injections  of an  organomanganese  compound, MAA,  elicited statistically
significant  Increases  1n Injection  site  tumors 1n  both  sexes  of  F344  rats
(Furst, 1978).  Oral  administration of manganese powder for  12  months  twice
monthly did  not  Induce lymphomas and/or  leukemlas or  flbromas In either sex
of  F344 rats  (Furst,  1978).   Although  the  results  of  the  studies with  diva-
lent manganese  are suggestive  of  carcinogenic activity,  non-natural  routes
of administration were employed.
    Some  reported animal studies  Imply a carcinogenic potential  for  manga-
nese,  but  the data  are  Inadequate  to  support this conclusion  (I.e.,  local
Injection  site  sarcomas  1n F344 rats,  a  marginal  response 1n Strain A  mice,
and  Inadequate  data   1n  the  experiment with  DBA/1  mice).   No ep1dem1olog1c
Information  relating  manganese  exposure  to cancer  occurrence 1n  humans has
been located.   Using  IARC criteria (IARC,  1980), the  available  evidence for
manganese  cardnogenldty would  be  rated  Inadequate  for animals  and "no data
available" for  humans  (Group 3).   Consequently,  the documented toxic effects
are of more practical concern.
9.3.   SPECIAL GROUPS AT RISK
    Several  researchers  have mentioned the marked  differences 1n Individual
susceptibility to Inhaled manganese (Rodler,  1955;  Penalver,  1955;  Cotzlas,
1805A                               9-5                              5/09/83

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1958).  They speculated that  this may  have  been  caused  by alcoholism,  syphi-
lis,  carbon monoxide,  lesions of the excretory  system,  or  the  physiological
or  pathological  condition  of  the respiratory tract.  While  1t  1s  reasonable
to  assume  that  an  Individual  with  an  Impaired  ability  to  clear  Inhaled
manganese  or  to excrete  absorbed manganese  would be  at Increased risk  of
adverse effects, no studies exist to confirm this.
    Experimental  studies   suggest  that  populations   at  greatest  risk  of
adverse effects  due  to manganese exposure are the  very  young and  those with
Iron  deficiency.   The  evidence for  Increased  absorption  and  retention  of
manganese  occurring  1n Iron  deficiency was  shown  1n  an  Inhalation  study  1n
humans (Mena et al., 1969,  1974), dietary studies  1n  humans (Thomson et al.,
1971), and  1ngest1on studies  1n  experimental  animals  (Rehnberg  et  al.,  1982;
Kostlal et al., 1980).
    Ingestlon  studies  give useful Information on  the effects  of  Inhalation
exposures  because  most Inhaled manganese 1s  cleared  to  the gastrointestinal
tract.   The early neonatal  period  may  be critical  for metal  accumulation
because  the very  young also have  an  Increased  Intestinal absorption  and
retention  of manganese.  This has  been demonstrated  1n  preweanllng  mice and
rats  (Kostlal  et  al.,  1978;  Rehnberg  et  al., 1980) and  1n  Infants  (Mena  et
al.,  1974).   High  retention  of  manganese 1n  the  tissues,  particularly the
liver  and  brain,  1s associated  with the  limited  excretion of manganese  1n
the preweanllng rat (Miller et al.,  1975).
    Kostlal  et  al.   (1978)   report  that  oral  toxldty  measured  by  LD™
values 1s  greater  1n very young  (2  weeks) as well as  old  (54 weeks)  rats,
but  not  as high  as  expected based  on  the  rate  of  Intestinal  absorption.
Although  the  neonate  has  not been  shown to  have Increased sensitivity  to
metals,  the  early  accumulation of  manganese  must  be  considered  as  an
additional risk factor.

1805A                               9-6                              5/05/83

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    Another population  at  high risk  1s workers  exposed  to manganese at  or
near the  recommended  TLV.   Because neurological  symptoms have  been  reported
                                                       3
at  concentrations  below this  limit, the TLV  of  5 mg/m  has a  low margin  of
safety.
9.4.   EFFECTS OF MAJOR CONCERN AND EXPOSURE/RESPONSE INFORMATION
9.4.1.    Effects of Major  Concern.   The key health  effects  of  manganese are
1n  the CNS and  the  lungs.   The  effect  on the CNS, manganlsm, 1s Irreversible
and severely  Incapacitating although not directly associated with lethality.
                                                         3
The  pulmonary effects  reported at  levels  below 1 mg/m   are  for   the  most
part  reversible  but  can  limit  function  or  Impose  disability   such  as
Increased  wheezing,  bronchitis, or  Increased susceptibility  to respiratory
Illness.  The lowest  reported exposure  levels  associated  with life  threaten-
ing diseases  such  as pneumonia have  been similar  to  ranges associated  with
                                              3
chronic manganese poisoning, e.g.,  0.1-14 mg/m  (Lloyd-Davles, 1946).
    Several endpolnts  suggested as  effects  from exposure   to  manganese are
nonspecific,  Inconclusive  or lack  documentation  In humans,  such as  degenera-
tive changes  1n  the  testes, or  decreased blood pressure.   Sexual dysfunction
has often been  reported  as an  early effect of manganlsm at  levels associated
with other effects on the  CNS.
9.4.2.    Exposure/Response  Information.   Tables  6-1  and 6-3  show that  human
                                 3
exposure  to  levels below  5 mg/m   has  been associated with adverse effects
to  the  CNS.   These effects are either  advanced  manganlsm or a constellation
of  signs  Indicative of  early  stages of  the disease (Suzuki et  al.,  1973a;
Chandra et  al.,  1981).  There  1s  some  evidence  suggesting that exposure  to
                     3
levels   below  1  mg/m   1s  associated  with  nonspecific  symptoms  which  are
common  1n early  manganlsm  and with abnormal  neurological  findings.   However,
1n  studies  at these levels the findings reported  could  not be definitively
attributed to manganese exposure (Sarlc et al., 1977; Chandra et al., 1981).

1805A                               9-7                              5/06/83

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    Studies of respiratory effects  1n  humans (summarized 1n Table  6-8)  show
pulmonary  system  adverse effects  at  levels  below 1 mg/m  .   Schoolchildren
                                                            3
exposed  to manganese  emissions  estimated  at  -3-11  vg/m   from  a  ferro-
manganese plant  developed  an  Increase 1n respiratory  symptoms  compared  with
controls such as sore throat, wheezing and  sputum  on  arising (Nogawa et  al.,
1973).  Sarlc and  Luc1c-Pala1c  (1977) reported  Increased  chronic  bronchitis
                                     3
1n  workers   exposed  to  0.4-16  mg/m   but   the  results  at  ambient  levels
       3
<1 mg/m   (Sarlc  et  al.,   1975)   were  Inconclusive   because  no   exposure-
response relationship was seen and confounding factors were not controlled.
    There are  many  pulmonary  endpolnts  that  vary  according  to  level  of
exposure.  Although  exposure  ranges  are so broad  that  the exposure/response
relationship 1s  sometimes  masked, a  continuum of  effects has  been  observed
which  qualitatively  supports  the   pulmonary  endpolnt.   Pulmonary  effects
reported and supported  Include  pneumonia (Elstad,  1939;  Lloyd-Davles,  1946;
Wassermann and  M1ha1l,  1961), chronic bronchitis  {Lloyd-Davles, 1946;  Sarlc
and  Luc1c-Pala1c,  1977), radlographlc changes  and flbrosls  (Wassermann  and
M1ha1l, 1961) and airways disability (Nogawa et al., 1973).
    Animal  studies   also   qualitatively  support   the  association  between
pulmonary effects  and manganese  exposure.   Table  9-1  summarizes  the animal
studies  of   the  adverse  effects  of  manganese  Inhalation.   Pathological
changes and decreased resistance  to  Infection occur  1n  a  variety  of species
                           3
at  levels  above  0.7 mg/m  .   Inflammatory  reactions  and decreased  resist-
ance  to Infection have been observed  1n mice  (Malgetter et al., 1976; Adklns
et  al.,  1980c).  N1sh1yama  et al.  (1975)  report  pulmonary  congestion  and
Inflammatory  changes 1n mice  and  monkeys after  5  months  exposure  to  3
    3                                         3
mg/m   and  less  severe  changes  at  0.7  mg/m .    Suzuki  et  al.  (1978)  de-
scribe  radlologlc changes  after  10  months  of  exposure  to 3 and 0.7 mg/m3.
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                                  TABLE  9-1



    Studies  of  Manganese  Inhalation  1n  Animals  —  Summary  of  Effect  Levels
Species

Mouse
Guinea pig
Guinea pig

Mouse
Mouse
Mouse
Mouse
Monkey
Monkey
Mouse
Monkey
Monkey
Guinea pig
Mouse
Duration

1-3 months
6 months
7.5 months

15-21 days
29 days
39+20 days
14 days
5 months
10 months
14 days
5 months
10 months
1 day
1-4 days
Concentration
(mg/m3)
Ferromanganese
NR
2350
2350
Mn02
NR
NR
NR
0.7
0.7
0.7
3.0
3.0
3.0
22
109
Result*

NOEL
NOEL
unclear

PEL
NOEL
unclear
LOAEL
LOAEL
LOAEL
PEL
PEL
PEL
PEL
PEL
Reference

Heine, 1943
Heine, 1943
Heine, 1943

Lloyd-Davles,
1946
Jotten et al. ,
1939
Jotten et al. ,
1939
N1sh1yama et al. ,
1975
N1sh1yama et al. ,
1975
Suzuki et al . ,
1978
N1sh1yama et al. ,
1975
N1sh1yama et al. ,
1975
Suzuki et al. ,
1978
Bergstrom, 1977
Malgetter et al.,
1976
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                              TABLE  9-1  (cont.)
  Species
                Duration
Concentration
Result*
Reference
Monkey
Hamster
Mouse
Mouse
               15 months
Rat, monkey    9 months

Rat, monkey    9 months

Rat            2 months
               2 months
               2 hours
               2 hours
      Mn304

     0.10          NOEL


     1.1           NOEL

     0.11          NOEL

     0.12          NOEL
 engine exhaust

     0.12          NOEL


     0.89          NOEL


  0.22-2.66        LOAEL
           Coulston and
           Griffin, 1977

           UlMch,  1979c

           Ulrlch,  1979c

           Moore et al.,
           1975

           Moore et al.,
           1975

           Adklns et al.,
           1980a

           Adklns et al.,
           1980c
*NOEL   No-Observed-Effect Level:   That exposure level at which  there are  no
        statistically  significant   Increases   1n  frequency  or  severity  of
        effects between the exposed population and  Us appropriate  control.

 NOAEL  No-Observed-Adverse-Effect   Level:    That   exposure   level   at   which
        there  are  no  statistically  significant  Increases   1n  frequency  or
        severity of  adverse effects  between  the  exposed population and  Its
       'appropriate control.   Effects are produced  at  this  level, but  they
        are not considered to be adverse.

 LOAEL  Lowest-Observed-Adverse-Effect Level:  The  lowest  exposure level  1n
        a study or group  of  studies which  produces  statistically significant
        Increases   1n  frequency or  severity  of adverse  effects between  the
        exposed population and Us  appropriate control.

 PEL    Frank-Effect  Level:  That exposure level which  produces  unmistakable
        adverse effects,  ranging from reversible hlstopathologlcal  damage  to
        Irreversible  functional Impairment or mortality, at a  statistically
        significant  Increase  1n  frequency or  severity between  an  exposed
        population and Us appropriate control.
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                                    9-10
                                       5/09/83

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Table 9-1  summarizes  several  studies  which report  no gross  or  microscopic
                                   3
changes after exposure to ~0.1 mg/m  Mn304.
    Thus,  the  animal  data  qualitatively  support  a  range   of  respiratory
effects  associated with  exposure  to  manganese.   Human  data qualitatively
describe such  effects  but  have limited exposure/response Information because
exposure ranges  are broad,  cohorts  are  not followed  for  long time periods,
and  duration of exposure  1s unreported  or  variable within  a study popula-
tion.  Therefore,  the  health effects assessment  centers on the highest NOELs
or  the  LOEL 1n  humans  which  are supported  by human  equivalent  exposures
derived  from animal data.
9.5.   HEALTH HAZARD EVALUATION
9.5.1.   Critical  Effect and  Effect  Levels.   The  critical  effect  1s  that
adverse  health  effect  which  occurs   at  the  lowest  level of  exposure.   In
order  to Identify  the critical  effect,  the highest no-observed-effect-level
(NOEL)   and   the  lowest-observed-effect-level  (LOEL)  for   relevant  toxic
effects  are  Identified and  compared.   Qualitative results and dose/response
data  from  experimental  animals  are  compared  with  levels  based  on  human
experience.   Studies  In  humans report  effects  on the respiratory symptoms at
levels   below  1 mg/m   whereas  studies  of  effects  on the  CNS  below this
level  are  equivocal or negative.  Two studies give exposure  response  Infor-
mation  1n  humans for  the  critical  effect.   Nogawa et al.  (1973) reported an
Increased  prevalence  of  respiratory  symptoms 1n  schoolchildren  exposed to
                 3
0.003-0.011  mg/m   manganese emission  from a  ferromanganese  plant.  This 1s
the   lowest-observed-adverse-effect  level   (LOAEL)   1n humans.    Sarlc  and
Luc1c-Pala1c (1977) report  an  Increased  prevalence of chronic bronchitis 1n
                                3
workers  exposed to  0.4-16 mg/m ; however,  prevalence of  chronic  bronchitis
                                                      3
1n  a  group  of  workers  exposed  to  0.005-0.04  mg/m   did  not  differ from
 1805A                               9-11                              5/09/83

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controls.  These  results do  not contradict  the results  of Nogawa  because
1) children  may  be  expected  to  be more  sensitive than  male  workers,  and
2) the latter  study  had less statistical  power  because fewer  subjects  were
Involved.
    NOELs  could   be  derived  from  several  studies reported  1n  laboratory
animals  exposed  to  manganese  oxides consisting  largely of  particles  1n  the
alveolar   fraction   (<2 iim,   see  Section  3.6.4.1.).   These   studies   are
summarized 1n  Tables  6-10  and  9-1.   Factors  which compromise  the  use  of
these studied for NOELs are  described  below.
    Coulston  and  Griffin  (1977)  did not  perform tests  of  lung  function,  did
not give  details  of  the pathological  examination and reported  acarlasls  and
associated pulmonary  complications  1n  a  majority  (8/12)  of  the  animals
studied.   Moore  et  al.  (1975)  reported  no  gross  or microscopic  abnormali-
ties; however, they  observed  the animals  for  only  8 hours/day  and  for  only
56 days.   Ulrlch et  al. (1979a,b,c)  exposed rats  and squirrel monkeys  to
three levels of  manganese and a  control  for  9 months.   This study  also  had
deficiencies  which   reduced  confidence  1n the  range  of  negative  findings
reported.  Due  to  the  small  group  size  of   the  monkeys  (4   males  and  4
females)   and  the  large within  group  variability,   1t  lacked  sufficient
statistical  power  to detect any  but  the  largest  changes 1n the  parameters
measured.  The variability could  have been reduced  by using  more appropriate
statistical  analysis to  control  for within group variation.   The description
of lung  pathology was  Inadequate.   Negative  results were  reported  at  1.15
    3
mg/m ; however,  Suzuki  et  al.  (1978)   reported pathologic  changes  1n  the
                                                 o
lungs  of  rhesus  monkeys  exposed  to 700  iig/m  of MnO?  for  10  months.
1805A                               9-12                             5/09/83

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Based  on  these  data,  the  next  highest  NOEL  reported  by  Ulrlch  et  al.

                           3
(1979a,b,c) was  0.113  mg/m .   However,  the  repeated reports  of  the  absence

                                                                           3
of  gross  and  microscopic  abnormalities  at  a   similar   level  (0.1   mg/m )


suggest that this level may be close to a threshold.


    These data do not  exclude  the  possibility  that  more subtle toxic  effects

                                       3                                   3
on  the  lungs  may  occur  at  -0.1  mg/m  .   Effects   do  occur  at  0.7  mg/m .

                                                     3
In  order  to   compare  the  reported  NOEL  (0.1  mg/m )  and  the  LOAEL  (0.7

    3
mg/m )  to  similar  data 1n  humans,  1t would be  helpful to  estimate  a  human


Intake  equivalent   to   that  of  the   experimental   animals.   The  suggested


approach 1s provided 1n the Appendix.
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                               10.   REFERENCES






Abernathy,  R.F.,  M.J.  Peterson  and  F.H.   Gibson.   1969.   Spectrochemlcal



analysis  of  coal  ash  for  trace elements.   Bur.  Mines Report  of  Investiga-



tions 7281.  U.S.  Dept. Interior, Pittsburgh, PA.   30 p.







Abrams,  E.,  J.W.  Lasslter,  W.J.  Miller,  M.W.  Neathery  and  R.P.  Gentry.


                                                              54
1976a.   Effect  of dietary  manganese  as a  factor affecting    Mn  absorption



1n rats.  Nutr. Rep. Inter.  14(5): 561-565.







Abrams,  E.,  J.W.  Lasslter,  W.3. Miller, M.W. Neathery, R.P.  Gentry and R.D.



Scarth.   1976b.   Absorption  as  a factor 1n  manganese  homeostasls.   J.  Anlm.



Sc1.  42(3): 630-636.







ACGIH  (American  Conference  of   Governmental  Industrial  Hyg1en1sts).   1958.



Committee  on Recommended Analytical  Methods:  Determination  of manganese 1n



air,  perlodate oxidation  method.   In:  Manual  of Analytical  Methods  Recom-



mended  for  Sampling and  Analysis  of Atmospheric  Contaminants.   ACGIH,  Cin-



cinnati,  OH.  Mn-1, Mn-4.






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 1800A                                 10-70                          05/09/83

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U.S.  EPA.   1979b.  Ferroalloy  process emissions  measurement.   NTIS  PB  293
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1800A                                 10-71                          05/09/83

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                                   APPENDIX
        ESTIMATING HUMAN EQUIVALENT INTAKE LEVELS FROM ANIMAL STUDIES
TERMINOLOGY
    The  quantitative  evaluation of  potential health  hazards 1s  based  upon
estimates  of  the  threshold exposure  level  for  the  critical  effect.   The
threshold estimate  1s  bracketed by the highest NOEL  (see  Table  9-1) and the
LOAEL.  The values  for  the NOELs and  LOAEL  depend  on  which  health effect 1s
considered.  The  estimate  of  the human threshold level  1s more  uncertain 1f
animal data are used since  there  1s  presently limited  Information on species
differences regarding toxic responses.
    Human  equivalent  Intake  rate (HEI)  1s  defined  here as the  estimated
exposure  level  based  on animal  data  which would cause  the  same  severity of
health effect 1f  continued  over  the  same  fraction of  Hfespan as used 1n the
animal  study.    The conversion  for  manganese  assumes  that 1f  the  ratio
(exposure  level)/(body  surface  area)  1s the  same 1n humans  as  1n the animal
study, then effects of the same severity will occur.
CRITICAL EFFECTS AND ESTIMATED EFFECT LEVELS
    The  lowest  exposure  level  for humans associated with  adverse effects 1s
                       3
a  LOAEL  of  3-11  y.g/m   for   respiratory  effects  1n  children   reported  by
Nogawa  et  al.   (1973).   Comparison among  studies  of  respiratory  effects In
laboratory  animals  (summarized  1n  Table  9-1)  shows  that Ulrlch et  al.
(1979a,b,c) and  Suzuki  et al.  (1978)  utilized the longest  exposure periods
                                        3
at  exposure  concentrations  -100  v-g/m  .    Therefore,  these  studies  were
selected  for  these calculations.   The  HEI  1s  estimated from  the  data from
experimental animals by the following:
                                             /     \
                                                  k2/3
                       HEI = CA x DE x Br x t
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where  C.  = concentration 1n air 1n the animal  study 1n ug/day
       Or  = fraction of day experimental animals were exposed
                                                3
       Br  = volume of air breathed per day 1n m
       W   = body weight of the experimental  animal  1n kg
        a
This conversion 1s based on the following assumptions:
    1.  Agents that are  1n  the form of  partlculate  matter  are expected
        to be absorbed and retained proportional to  the breathing rate.
    2.  The fraction retained 1s approximately the same for  all species.
    3.  The conversion  from animals to  humans  based on  exposure  level
        per  body  surface  area more  accurately  reflects   differences
        among  species  than does a  mg/kg body weight  conversion  (Rail,
        1969).  The surface area ratio  1s  well  approximated by the body
        weight ratio to the 2/3 power (Calabrese, 1983).
    The estimation  of  HEI  1s  based  on Intake by Inhalation  of  manganese  1n
excess of  dietary  Intake  of this essential element  because all  studies  used
here were  so  designed.  Also,  a  sufficient oral  Intake and  strong homeostat-
1c  control  can be assumed  so  that excess exposure  1s  appropriate.   Inhala-
tion studies should be used since the critical effect 1s route specific.
    The estimated  HEI  (1n  mg/day)  1s  converted to  a  human equivalent  expo-
sure level  (HEEL) by dividing  by the average  dally  human respiratory rate  of
    3
20 m /day.  All calculations are summarized 1n Table A-l.
    In  the studies  considered  here  D    equals  1.    Therefore,   for  rhesus
monkeys 1n  the study by Suzuki et al. (1978)
               HEI = CA x Br x f—
                               V  *a/
                   = 700 ug/m3  x 1.4 mVday x/70 kfl
                                              \3.5 kg,
                   = 7293
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CD
O
                                                                                TABLE A-l

                          Exposure Effect Information for  Health Hazard Evaluation:  Human  Equivalent Exposure Levels Estimated from Animal Data
Species
                                                        Animal  Intake Level    Estimated Human Intake Level
                         Response Level     Exposure
                                              vg/day    ixg/kg/day
                                                                                    ug/day   ug/kg/day
  Estimated Human
Equivalent Exposure
   Level (HEEL)
                                                                                                                              Adjusted
                                                                                                                                HEEL*
                                                                                                                                                       Reference
1
CO


Rat
Squirrel monkey
Rhesus monkey
reported
reported
LOAEL
NOELb
NOELb

113
113
700
29
81
980
84
113
280
1022
1740
7293
15
25
104
51
87
365
5
8.7
36.5
UlMch et al.,
1979a,b.c
Ulrlch et al.,
1979a,b,c
Suzuki et al.,
                                                                                                                                                     1978
in
\
O
co
CO
      aThe estimated  HEEL 1s adjusted  by  dividing by an  uncertainty  factor of  10  to compensate  for  the heterogeneity In human  populations  and thereby protect
       the sensitive Individual.

      bThese NOELs are used to compare human and animal data despite some limitations which exist 1n the study.  See text for further discussion.

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                                                                       3
The HEEL  obtained  by  dividing  by the  dally respiratory volume  (20  m /day)
1s  365 ug/m -   Note  that  this  HEEL  1s  based  on  a  LOAEL  and  thus  may  be
above the human threshold level.
    Similar calculations using  data  on  rats  from Ulrlch et  al.  (1979a,b,c)
(VJ  = 0.35  kg,   Br = 0.26  m3/day,   and  C. = 113   ug/m3)  result   In   a
  3                                          A
HEEL  of   51  H9/m3.   For  the   Ulrlch  et  al.  (1979a,b,c)  data  on  squirrel
monkeys   (W3  = 0.72  kg,   Br  = 0.72   m3/day,   and   C.  =  113  ug/m3)   the
            a                                            A
HEEL 1s 87
    These  results,  shown 1n  Table A-l , can  be  compared with  the  data from
Nogawa  et  al.   (1973)   on   children  who  had  an  estimated  LOAEL  of  3-11
    3
ug/m  .   The  data  obtained  from  human  data  1s,  of  course,  crucial  for
public  health  decision  making.   This  level  might  be expected to  be lower
than  the  animal  level  for  the following  reasons:   1) the studies  on animals
have  flaws  resulting   1n  uncertainty  as  to  whether  adverse effects  are
missed; 2) certain  endpolnts  studied  1n humans  cannot be ascertained as well
1n  animal  studies  and  are  likely  to be  overlooked; and  3)  children  are a
sensitive  group.   A better  comparison  between  animal  and  human data  1s
obtained  by  dividing the HEEL  by  10  to  compensate  for  the heterogeneity 1n
the human  population and to better protect the sensitive Individual (Dourson
and Stara,  1983).   The  range of  adjusted HEELs from  the  animal  NOELs and  the
                      o
LOAEL   1s   5-37  y.g/m  ,   and  supports  the  human   LOAEL  of  3-11
observed  1n a sensitive  population.
                                               ..-, ,-,- ''-ay
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