EPA/600/R-12/047F5 | December 2012 | www.epa.gov
United States
Environmental Protection
Agency
Inhalation Health Effect Reference
Values for Manganese
(CASRN 7439-96-5 - Manganese)
and Compounds (CASRN 1344-43-0;
1317-35-7; and 1129-60-"
Mn
CASRN 7439-96-5
Mn
S
CASRN 1317-35-7
Mn
CASRN 1344-43-0
O2~ Mn2+
CASRN 1129-60-5
National Center for Environmental Assessment
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC
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tii Office of Research and Development
National Centerfor Environmental Assessment ,. M
Research Triangle Park, NC Manganese
December 2012
Inhalation Health Effect Reference Values for Manganese and Compounds
(CASRN 7439-96-5 - Manganese)
Overview
The reader is strongly encouraged to read Section 1 of the following report for critical
background information regarding the health effect reference values discussed in this summary:
Graphical Arrays of Chemical-Specific Health Effect Reference Values for Inhalation Exposures
[FinalReport] (U.S. EPA, 2009a). This report is available on-line at
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003.
This summary presents noncancer health effect reference values for inhalation exposures
to manganese (Mn) across all durations for both the general public and workers. The physical
size of Mn-containing particles has a bearing on the toxicity and some organizations have created
different reference values based on size fraction, therefore some definitions of terms regarding
particle size are provided below.
A detailed description of the reference values compared in this summary and the
categories of reference values can be found in Section 1 of the EPA report (U.S. EPA, 2009a). In
general, inhalation health effect reference values have been included which have been developed
and formally reviewed by an authoritative governing body (government agency or professional
association) for use in assessments of risk to support regulatory decision-making. The main
exception to this inclusion criteria are the Provisional Advisory Concentration (PAC) and
Temporary Emergency Exposure Level (TEEL) values for emergency response, which are the
only emergency response values available for manganese compounds. Another exception is the
discussion of a proposed reference value developed by Bailey et al. (2009) and reviewed by a
panel convened by Toxicology Excellence for Risk Assessment (TERA, 2011): this value was
not developed or endorsed by an agency or professional association which typically develops
such reference values.
General Properties
Manganese (Mn) occurs naturally in many types of rocks and soil, usually as a salt or
other compound in combination with other elements such as oxygen, sulfur, and chlorine
(ATSDR, 2012). The average concentration of manganese in urban air (as a component of PMio)
is approximately 0.04 |ig/m , ranging from < 0.01 |ig/m3 for remote areas and up to 0.089 |ig/m
in areas near industrial sources of manganese emissions (ATSDR, 2012). Manganese is a
necessary trace nutrient, but is toxic at high levels of exposure.
Production and Uses
Manganese is used to improve hardness, stiffness, and strength in the production of
various varieties of steel (carbon steel, stainless steel, high-temperature steel, and tool steel)
(ATSDR, 2012). Manganese also occurs naturally in most foods and is often a component of
nutritional supplements. Manganese is used in a wide variety of other products, including:
fireworks; dry-cell batteries; fertilizer; paints; a medical imaging agent; in cosmetics; and as an
octane boosting additive to gasoline.
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National Centerfor Environmental Assessment ,. M
Research Triangle Park, NC Manganese
December 2012
Exposure Potential
The Toxics Release Inventory for 2010 (U.S. EPA. 2010) reported 1,641,992 pounds of
manganese were emitted to air from all industrial sources in the United States, with 111,391
pounds emitted from point sources (stacks, vents, ducts, or pipes) and 1,530,600 pounds coming
from fugitive sources (equipment leaks, losses from surface impoundments and spills, and
releases from building ventilation systems).
Potential Health Effects
The adverse effect most commonly associated with inhalation exposure to Mn is
neurological (ATSDR, 2012; U.S. EPA, 1993). Mn and compounds have not been associated
with cancer. Developmental and reproductive effects have not been investigated adequately for
characterizing those potential risks.
Most health effect reference values for inhalation exposure to manganese-containing
compounds are based on the Mn concentration, with no distinction made based on the valence
state of the Mn ion, with Mn(II), Mn(III), and Mn(IV) most commonly encountered. However,
more soluble Mn salts have been associated with greater bioavailability.
Cancer Potential
The US EPA (U.S. EPA, 1993) has stated that manganese is "not classifiable as to human
carcinogenicity" This conclusion was based on the assessment that "existing studies are
inadequate to assess the carcinogenicity of manganese''
Particle Size Definitions
The location in the respiratory tract (extrathoracic, tracheobronchial, alveolar) where Mn-
containing particles may be deposited is a determinant of toxicity. Many organizations refer to
various particle size fractions (respirable, thoracic, and inhalable), with some slight variations in
size cut-offs and in terminology, often with overlapping categories. The following definitions
come from the Integrated Science Assessment for Particulate Matter (U.S. EPA, 2009b), and are
generally applicable to the remainder of this discussion:
• Particulate Matter (PM) - PM is the generic term for a broad class of chemically and
physically diverse substances that exist as discrete particles (liquid droplets or solids)
over a wide range of sizes.
• Total SuspendedParticulates (TSP) - Particulate matter up to a nominal size of 25-45
micrometers (um).
• PMw -Particulate matter with a nominal aerodynamic diameter1 less than or equal to
10 |im (50% cut point of the sampler). PMiodelineates the subset of inhalable
particles, referred to as thoracic particles, that are small enough to penetrate to the
thoracic region (including the tracheobronchial and alveolar regions) of the
respiratory tract.
1 The more precise term is 50% cut point or 50% diameter (d50). This is the aerodynamic particle diameter for
which the efficiency of particle collection is 50%. Larger particles are not excluded altogether, but are collected with
decreasing efficiency which approaches zero for 20 um particles. Smaller particles are collected with increasing
efficiency (up to around 100%) for less than 3 um particles.
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National Centerfor Environmental Assessment ,. M
Research Triangle Park, NC Manganese
December 2012
• PM2.5 - Particulate matter with a nominal aerodynamic diameter less than or equal to
2.5 |im (50% cut point of the sampler), an indicator for fine particles.
The ISA for PM (U.S. EPA, 2009b) also notes the following regarding particle size and
dosimetry:
"Particles of different sizes can penetrate different regions of the human respiratory
tract. Thoracic particles refer to particles that travel past the larynx to reach the lung
airways and the gas-exchange region of the lung, and respirable particles are those that
reach the gas-exchange region. Respiratory tract dosimetry supports the choice ofPMjo
as an index of thoracic particles. However, dosimetric considerations do not provide
insight into the selection of a size cut to characterize a fine particle mode. American
Conference of Governmental Industrial Hygienists (ACGIH, 2005), the International
Standards Organization (ISO), and the European Standardization Committee (CEN) have
adopted a 50% cut point of4jum as an indicator of respirable particles. "
Airborne particles have been classified into different aerosol fractions based on the
penetration of these particles in the various regions of the respiratory tract by the American
Conference of Governmental Industrial Hygienists (ACGIH) and European Committee for
Standardization (CEN). The definitions adopted from the European Committee for
Standardization (CEN, 1993), are shown below:
• Inhalable fraction - the mass fraction of total airborne particles which is inhaled
through the nose and mouth.
• Thoracic fraction - the mass fraction of inhaled particles penetrating beyond the
larynx, which is inclusive of the trachea and bronchi.
• Respirable fraction - the mass fraction of inhaled particles penetrating to the
unciliated airways. More typically, the literature have defined this term in relation to
the fraction of particles entering the gas-exchange region or the fraction penetrating
through the tracheobronchial region, the ciliated airways, or conducting airways.
The above definitions are stated in terms of a mass fraction. Relative to total airborne
particles, the particle size having 50% penetration for the thoracic and respirable fractions are 10
urn and 4.0 urn, respectively (ACGIH, 2005; CEN, 1993).
Many of the values developed for application to the general public assume exposure to
the respirable fraction as being protective for exposure to larger particle fractions and are
applicable to that fraction, unless specifically noted in the following text and table.
Emergency Response Values
No peer-reviewed emergency response values (Acute Exposure Guideline Levels -
AEGLs, or Emergency Response Planning Guidelines - ERPGs) have been developed for Mn.
The Provisional Advisory Concentrations (PACs) include an AEGL or ERPG value when
available, and Temporary Emergency Exposure Levels (TEELs) values when they are not, using
a methodology developed by the Department of Energy (DOE, 2008). Both the TEEL-1 and -2
values for Mn draw largely from the occupational values (See Figure 1 and Table 1), in keeping
with the DOE methodology, and were not independently developed. There were major changes
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National Centerfor Environmental Assessment ,. M
Research Triangle Park, NC Manganese
December 2012
in the PAC values for manganese going from Revision 26 (DOE, 2010) to Revision 27 (DOE,
2012): all TEEL-0 values were dropped from the tables in the later version (including the value
of 0.2 mg/m3 for Mn) and the PAC-3 value increased from 500 mg/m3 in Revision 26 up to 1,800
mg/m3 in Revision 27. The PAC-3 was equivalent to the NIOSH IDLH (see below) in Revision
26. Although no documentation is currently available to the public documenting the basis for the
revised PAC-3, it was based on a TEEL-3 value calculation . The TEEL-3 for manganese is
based on a rat oral LD50 of 9 g/kg obtained from the Registry of the Toxic Effects of Chemical
Substances (RTECS) database, and derived using the DOE TEEL methodology (DOE. 2008).
Occupational Values
Typically, there is less publically available information regarding the derivation of
occupational values which are formulated based on a weight-of-evidence (WOE) approach and
judgement by a panel of experts; therefore, fewer details are provided here on the derivation of
occupational values. The National Institute for Occupational Safety and Health (NIOSH) and the
American Conference of Governmental and Industrial Hygienists (ACGIH) have established
Time-Weighted Average (TWA) values for exposure levels during the course of a working day,
with assumptions of exposures repeated 5 days per week, for up to a 40-year career. See Figure 1
and Table 1 for additional comparison of the occupational values described below. The NIOSH
Recommended Exposure Level (REL) is 1 mg/m3 (NIOSH. 2007) and the ACGIH Threshold
Limit Value (TLV ) is 0.2 mg/m3 (200 |ig/m ) (ACGIH. 1996). Additional assumptions of a
healthy adult worker population are included in the derivation of these occupational values. The
Occupational Safety and Health Administration (OSHA) Ceiling value and NIOSH Short-Term
Exposure Level (STEL), for exposure durations of 15 minutes or less, have been established at 5
mg/m3 and 3 mg/m3, respectively, to protect workers from spikes in exposure that may not be
reflected on a TWA basis (NIOSH, 2007). All of these occupational values are for the respirable
fraction with nominal particle aerodynamic diameter of 4 jim (see definitions above) and are
based on neurological effects observed in studies on occupationally exposed adults.
ACGIH has proposed changes (ACGIH, 2012) - Notice of Intended Change (NIC) - to
the TLV® TWA from the current 0.2 mg/m3 to a value of 0.02 mg/m3 (20 |ig/m3) for the
respirable fraction, and the addition of a separate value of 0.1 mg/m3 (100 |ig/m ) for the larger
inhalable Mn-containing particles (see particle size definitions above). These proposed changes
indicate concerns raised by the studies of Bast-Pettersen et al. (2004), Lucchini et al. (1999),
Mergler et al. (1994), and Roels etal. (1992), which indicated neurological effects in workers at
levels between 0.03 and 0.04 mg/m3, which is below the current TLV® TWA of 0.2 mg/m3 (i.e.,
the current value may not be protective enough). The inclusion of a separate value for the
inhalable fraction is in recognition of the potential for toxicity from these larger sized particles
due in part to intestinal absorption subsequent to inhalation exposure (swallowing of mucus with
entrained larger particles) and possible absorption of soluble particles deposited in the
nasopharynx, and due to the smaller particles (e.g., PMs) being included as a component of the
larger particle definition (e.g., TSP). It should be emphasized that the ACGIH is an independent
professional organization and not a governmental agency.
Correspondence between George Woodall (US EPA) and David Freshwater (US DOE), August 23, 2012.
4
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National Centerfor Environmental Assessment ,. M
Research Triangle Park, NC Manganese
December 2012
General Public Values (Routine Non-emergency Exposures)
IRISRfC
The current Reference Concentration (RfC) on IRIS (U.S. EPA, 1993) was derived using
the Lowest Observed Adverse Effect Level (LOAEL) of 0.15 mg/m3 (150 |ig/m3) from a study
of occupationally exposed workers (Roels et al., 1992) exhibiting neurological effects (visual
reaction time, eye-hand coordination, and hand steadiness). The LOAEL was duration adjusted
to 0.05 mg/m3 using a factor 2 to account for an assumption of 10 m3 of air inhaled during active
work versus 20 m3 inhaled over the course of a full day, and a factor of 5/7 to adjust for work
during 5-days/week. Following the duration adjustments, derivation of the final RfC
(0.05 |ig/m3) included application of a total Uncertainty Factor (UF) of 1000, with factors of 10
for inter-individual variability, 10 for going from a LOAEL to a No Observed Adverse Effect
Level (NOAEL), and 10 to account for database uncertainty (including the lack of data for
developmental and reproductive effects, as well as potential but unquantified differences in the
toxicity of different forms of Mn). The median cut point of 5 |im aerodynamic diameter for the
respirable fraction in the study of Roels et al. (1992) was used in the derivation of the RfC (U.S.
EPA. 1993).
California REL
The Office of Environmental Health and Hazard Assessment (OEHHA) of the State of
California developed Mn Reference Exposure Level (REL) values for both the 8-hour and
chronic durations (OEHHA, 2008) using their most up-to-date methodologies. The point of
departure (POD) was derived using benchmark analysis (U.S. EPA, 2008) on data from the same
study as used for the current RfC (Roels etal., 1992) to arrive at a BMCLos (the 95% lower
confidence limit of the benchmark concentration for a 5% effect level). REL values for both
durations were based on the same study, health endpoint, POD, and total UF (300); the main
difference between the two REL values was in the adjustments for duration, with the 8-hour
value only adjusted from 5-days/week to 7-days/week and the chronic value also adjusted to
account for a breathing rate of 10 m3 during the average 8-hour work day to an average 20 m3 in
a 24-hour day. The final chronic REL is 0.09 |ig/m3 and the final 8-hour REL value is
0.17 |ig/m3. OEHHA based their REL on inhalable particles with an assumption of a 3-4-fold
greater deposition of inhaled particulates in the 1-10 um range in the lungs of neonates relative to
adults exposed to similar particulate levels in ambient air (OEHHA, 2008).
Chronic3 A TSDR MRL
ATSDR posted a revision to the chronic Minimal Risk Level (MRL) for Mn (respirable
fraction) in December 2012 (ATSDR. 2012) of 0.3 |ig/m3. The MRL was derived using
benchmark analysis giving a 10% effect (BMCLio) of data from the same study as used in the
current EPA RfC (Roels et al.. 1992). The BMCLio of 142 |ig/m3 was adjusted from an
occupational to continuous exposure (5/7 days per week and 8/24 hours per day), resulting in an
adjusted value of 33 |ig/m3. Application of a total UF of 100 (10 for human variability; and 10
for database deficiencies and limitations) lead to the final MRL value of 0.3 |ig/m3. The previous
MRL included an additional factor of 5 to account for potentially increased susceptibility in
children based on differential kinetics in the young (ATSDR. 2010). However, ATSDR (2012)
cited recent toxicokinetic studies in lactating rats and their offspring exposed to manganese by
3 ATSDR defines chronic durations as being for periods of one year or longer.
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tii Office of Research and Development
National Centerfor Environmental Assessment ,. M
Research Triangle Park, NC Manganese
December 2012
the oral or inhalation routes which suggest that the human variability factor of 10 provides
sufficient protection for differential kinetics in children and adults.
Health Canada RfC
The chronic reference value developed by Health Canada (2010a) used a study of Italian
ferroalloy workers (Lucchini etal., 1999). Neurotoxic effects were noted and serum prolactin
levels were also observed to be affected. The results from a benchmark concentration analysis
for a BMCLos were duration adjusted from the occupational exposure of 8-h/day and
5-days/week, to 24-h/day and 7-days/week. Uncertainty factors of 10 for inter-individual
variability in response and 10 to account for limitations to the database (potential for the general
population to be exposed to more soluble forms of Mn; the lack of studies on prenatal effects;
and the impact of Mn on serum prolactin). "[The]... Health Canada reference concentration for
inhaled manganese is 0.05 fj,g/m3 in PMs.s. This value reflects the concentration to which the
general population, including sensitive subgroups, can be exposed for a lifetime without
appreciable harm (Health Canada, 201 Ob)."
World Health Organization Health Guidelines
The WHO (2000) developed a Health Guideline value of 0.15 |ig/m3 as an annual
average for exposure to Mn based on a BMCLos from the data reported by Roels et al. (1992),
with an adjustment factor of 4.2 to account for duration adjustments, and a total UF of 50 (10 for
human variability and a modifying factor of 5 for the potential for increased susceptibility in
children).
Ontario Ministry of the Environment (MOE) Ambient Air Quality Criteria and Standard
In 2011, the MOE updated their Ambient Air Quality Criteria (AAQC) and Standards for
Mn-containing particulates from a single AAQC and Standard based on total suspended
particulates (TSP) to one based on the smaller sized fraction of PM2.5 (MOE, 2011). The MOE
developed the AAQC for PM2.5 in much the same way as an RfC or other similar reference value
would be developed. Benchmark analysis was applied to the study data from Roels et al. (1992)
to arrive at a POD (BMCL0s) of 84 |ig/m3. Duration adjustments were applied in the same
manner as in the RfC and REL derivation arriving at an adjusted value of 30 |ig/m3. Application
of a total UF of 300 (10 for human variability, 3 for database limitations, 3 for vulnerability to
the developing nervous system, and 3 for subchronic to chronic extrapolation) led to final
derivation of an AAQC value of 0.1 |ig/m3.
Health Canada (1998) noted from observations across multiple monitoring sites that, on
average, approximately 50% of TSP consisted of PMio, and similarly 50% of PMio consisted of
PM2.5. Therefore, the MOE (2011) used the PM2.5 AAQC of 0.1 |ig/m3 and the previously
mentioned ratios as the basis for deriving AAQCs for PMio (0.2 |ig/m3) and TSP (0.4 |ig/m3).
The revised 24-hour standard for Mn and Mn-containing compounds in TSP was set to equal the
Mn AAQC for TSP (0.4 |ig/m3). An additional half-hour monitoring standard of 1.2 |ig/m3 was
also set for Mn and Mn-containing compounds in TSP.
ITER "Proposed RfC" for Manganese Oxide (MnO)
The "proposed RfC" for MnO was neither developed nor endorsed by an agency or
professional association which typically develops reference values. This value was based on a
paper from a peer-reviewed journal (Bailey et al., 2009) which was further reviewed by a panel
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tii Office of Research and Development
National Centerfor Environmental Assessment ,. M
Research Triangle Park, NC Manganese
December 2012
convened by TERA (2011), and placed on the International Toxicity Estimates for Risk
Assessment (ITER) database managed by TERA. Values from ITER are also available through
the National Library of Medicine TOXNET web site (http://toxnet.nlm.nih.gov). Although the
ITER values (chronic values of 2 |ig/m3 based on a NOAEL and 7 |ig/m3 based on a benchmark
dose analysis) have received a second level of review by TERA for methodological
considerations, the level of review was not deemed to be comparable to the reviews provided by
the other sources developing reference values. Additionally, no authoritative body (government
agency or professional association) has endorsed the use of these values for the purposes of risk
assessment; TERA states in their posting on ITER, "... the panel was not asked to explicitly
endorse the value derived by Bailey et al. (2009)." For these reasons, the ITER values for
manganese oxide are not included in the array shown in Figure 1 or described in detail in
Table 1.
Summary
The graphical array of the available health effect reference values for inhalation exposure
to manganese in Figure 1 includes all of the values described here and in Table 1, unless
otherwise noted. The Ontario Ministry of the Environment (MOE) 24-hour Standard for Mn is
equal to the TSP AAQC, therefore it was not included in the accompanying graphic or in the
table. Additionally, the Ontario MOE half-hour monitoring standard for Mn mentioned in the
text above was not included in the array or table. The Health Canada RfC (Health Canada,
2010a, b) is identical to the EPA RfC (U.S. EPA, 1993) and may be difficult to discern on the
graphic.
Some variability in the results from application of BMD analyses between organizations
using the same base study can be noted, for example when comparing the derivations of BMCL0s
values based on the study ofRoels et al. (1992) by OEHHA (0.072 mg/m3) versus the value
derived by MOE (0.084 mg/m3). On the other hand, the BMCLio value derived by ATSDR
(0.142 mg/m3) is within the range of values described in Clewell et al. (2003) (0.09 - 0.27
mg/m3). These apparent discrepancies are due in part to differences in application of the models
(e.g., model choice) and differences in policy and guidance between the organizations for
performing BMD analysis and interpretation of the results. These differences are noted here, but
further analysis or commentary is beyond the scope of this document.
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Figure 1. Graphic array of health effect reference values for inhalation exposure to manganese
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National Centerfor Environmental Assessment
Research Triangle Park, NC
Manganese
December 2012
Table 1. Summary information on the basis and derivation of the available reference values for inhalation exposure to
manganese
Emergency
Response
Occupational
Reference
Value Name
PAC-3
PAC-2
PAC-1
OSHA Ceiling
NIOSH STEL
NIOSHREL
(TWA)
NIOSH IDLH
ACGffl
TLV-TWA
(NIC5)
Duration
1 hour
1 hour
1 hour
<15
minutes
<10
minutes
10 hour
TWA
30
minutes
8 hour
TWA
Reference
Value
(mg/m3)
1800
(Respirable)
5
(Respirable)
3
(Respirable)
5
3
1
500
0.2
(0.02 -
respirable; 0.1
- inhalable)
Health Effect
NA
NA
NA
Manganism;
asthenia, insomnia,
mental confusion;
metal fume fever:
dry throat, cough,
chest tightness,
dyspnea, rales, flu-
like fever; low-
back pain;
vomiting; malaise;
lassitude; kidney
damage
CNS (manganism);
lung; reproduction
Point of
Departure
9000 mg/kg
OSHA
Ceiling
(see below)
NIOSH
STEL
(see below)
NR
Various
Various
5,282 mg/m3
1 mg/m3
Qualifier
Rat LD-50
inRTECS
(NIOSH.
2009)
NA
NA
NR
NA
NA
Adjusted
from Oral
Lethal Dose
in mice
LOLL
Principal
Study
Marhold
(1972)
NR
Gupta et al.
(1981)
(Roels et
al.. 1992;
1987)
Uncertainty
Factors4
NA
NA
NA
NR
NA
lotal Ul1 - 10
NR
Notes on
Derivation
PAC and
TEEL values
derived via an
approach
developed by
the
Department
of Energy
(DOE, 2008)
Adoption of
previous
ACGIH TLV
WOE
Approach
Total UF and
adjusted POD
from the IDLH
Documentation
(NIOSH, 1994)
WOE
Approach
Review
Status
Final
Revision 27
(DOE, 2012)
Final
(2006)
Final
(NIOSH, 2007)
Final
(ACGIH, 2001)
(NIC is draft)
4 Uncertainty Factor (UF) component definitions: UFH - inter-human variability; UFA - animal to human variability; UFL - LOAEL to NOAEL adjustment;
UFS - subchronic to chronic adjustment; UFDB - database uncertainty
5 Notice of Intended Change - the values in parentheses are the proposed change in TLV-TWA, and include separate values for respirable and inhalable
fractions.
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National Centerfor Environmental Assessment
Research Triangle Park, NC
Manganese
December 2012
General Public
Reference
Value Name
CA-REL
Chronic
ATSDR MRL
Chronic RfC
(IRIS)
Health
Canada RfC
Duration
8 hour
Chronic
Chronic
(> 1 year)
Chronic
Chronic
Reference
Value
(mg/m3)
i.vxicr4
(Respirable;
PM5)
9 x icr5
(Respirable;
PM5)
3 x icr4
(Respirable;
PM5)
5 x icr5
(Respirable;
PM5)
5 x icr5
(PM3.5)
Health Effect
Impaired
neurobehavior:
visual reaction
time, eye-hand
coordination, hand
steadiness
(Human)
Impaired
neurobehavior:
visual reaction
time, eye-hand
coordination, hand
steadiness
(Human)
Abnormal
performance in
tests of hand
steadiness, eye-
hand coordination,
or reaction time.
(Human)
Impairment of
neurobehavioral
function
Neurobehavioral
end points from a
study of
manganese alloy
workers
Point of
Departure
0.051 mg/m3
0.072 mg/m3
0.026 mg/m3
0.072 mg/m3
0.033 mg/m3
0.1 42 mg/m3
0.05 mg/m3
0.15 mg/m3
0.005 mg/m3
0.019 mg/m3
Qualifier
BMCL05.AD,
BMCL05
(5-d/wk,
mean of 5.3
yr)
BMCL05.AD,
BMCL05
(5-d/wk,
mean of 5.3
yr)
BMCLJO.AD,
BMCL10
LOAELADJ
LOAEL
BMCL05-ADJ
BMCL05
Principal
Study
Roels et al.
(1992)
Roels et al.
(1992)
Roels et al.
(1992)
Roels et al.
(1992)
Lucchini et
al. (1999)
Uncertainty
Factors4
Total UF = 300
UFH.k=10
UFH-d=10
UFS=3
Total UF = 300
UFH.k=10
UFH-d=10
UFS=3
Total UF = 100
UFH =10
UFDB = 10
Total UF= 1000
UFH = 10
UFL - 10
UFDB - 10
Total UF = 100
UFH = 10
UTcB = 10
Notes on
Derivation
Duration
adjusted from
5-d/week to
7-d/week.
Duration
adjusted6
Duration
adjusted from
5-d/week,
8-h/d to
7-d/week,
24-h/d
Duration
adjusted
Duration
adjusted from
5-d/week,
8-h/d to
7-d/week,
24-h/d
Review
Status
Final
(OEHHA, 2008)
Final
(ATSDR, 20 12)
Final
(U.S. EPA,
1993)
Final
(Health Canada,
2010a,b)
6 Duration adjusted from 5-d/week to 7-d/week, and for 10 m3 of air inhaled for an 8-hour work day compared to 20 m3 inhaled over a full day.
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rt Office of Research and Development
National Centerfor Environmental Assessment
Research Triangle Park, NC
Manganese
December 2012
Reference
Value Name
Ontario MOE
Ambient Air
Quality
Criteria
WHO Health
Guideline
Duration
Chronic -
based on a
24 hour
sampling
period
Chronic
(Annual
average)
Reference
Value
(mg/m3)
i.Oxicr4
(PM2.5)
2.0 x ICT4
(PMio)
4.0 x 10'4
(TSP)
l.SxlO'4
(PM5)
Health Effect
Neurological end-
point from an
occupational study,
5.3 year average
exposure.
Neurotoxicity in
adult workers
Point of
Departure
0.030 mg/m3
0.084 mg/m3
0.007 mg/m3
0.03 mg/m3
Qualifier
BMCL05.AD,
BMCL05
BMCL05-ADJ
BMCL05
Principal
Study
Roels et al.
(1992)
Roels et al.
(1992)
Uncertainty
Factors4
Total LTF = 300
LTFH =10
UFDB =3
LTFS =3
MF7 =3
Total LTF = 50
LTFH =10
MF9=5
Notes on
Derivation
Duration
adjusted8
Values for
larger size
fractions were
based on
effects seen
with PM2 5
Factor of 4. 2
used to convert
to continuous
exposure.
Review
Status
F 1113.1
(MOE, 20 11)
7 MOE termed this as an UF for "vulnerability of the Developing Nervous System;" it was termed a modifying factor in this document to be consistent with the
application by other organizations.
8 Duration adjusted from 5-d/week to 7-d/week, and for 10 m3 of air inhaled for an 8-hour work day compared to 20 m3 inhaled over a full day.
9 Modifying factor based on developmental effects in younger children "by analogy with lead where neurobehavioural effects were found in younger children at
blood lead levels five times lower than in adults and supported by evidence from studies of experimental animals."
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December 2012
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