vEPA
EPA/635/R-14/094
Preliminary Materials
www. ep a. go v/ir is
Preliminary Materials for the Integrated Risk Information System (IRIS)
Toxicological Review of Hexavalent Chromium Part 1:
Experimental Animal Studies
[CASRN 18540-29-9]
April 2 014
NOTICE
This document is comprised of preliminary materials. This information is distributed solely for
the purpose of pre-dissemination review under applicable information quality guidelines. It has
not been formally disseminated by EPA. It does not represent and should not be construed to
represent any Agency determination or policy. It is being circulated for review of its technical
accuracy and science policy implications.
National Center for Environmental Assessment
Office of Research and Development
U.S. Environmental Protection Agency
Washington, DC
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
DISCLAIMER
This document is comprised of preliminary materials for review purposes only. This
information is distributed solely for the purpose of pre-dissemination review under applicable
information quality guidelines. It has not been formally disseminated by EPA. It does not represent
and should not be construed to represent any Agency determination or policy. Mention of trade
names or commercial products does not constitute endorsement or recommendation for use.
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
CONTENTS
ABBREVIATIONS vii
PREFACE viii
1. INTRODUCTION 1-1
1.1. Hexavalent Chromium in the Environment 1-1
1.1.1. Chemical and Physical Properties 1-1
1.1.2. Sources and Uses 1-1
1.1.3. Environmental Fate and Transport 1-2
1.1.4. Environmental Concentrations 1-3
1.1.5. General Population Exposure 1-4
1.2. Scope of the Assessment 1-5
1.3. Problem Formulation 1-6
1.3.1. Assessments by Federal, State, and International Health Agencies 1-6
1.3.2. Toxicokinetics of Hexavalent Chromium 1-7
1.3.3. Cancer- inhalation route 1-8
1.3.4. Cancer-oral route 1-9
1.3.5. Noncancer effects 1-11
2. METHODS FOR IDENTIFYING AND SELECTING STUDIES 2-1
2.1. Draft Literature Search and Screening Strategy 2-1
2.2. Selection of Critical Studies in Early Stages of Draft Development 2-6
2.2.1. General Approach 2-6
2.2.2. Selection of Critical Experimental Animal Studies for Evidence Tables for
Hexavalent Chromium 2-7
2.2.3. Preliminary Evidence Tables and Exposure-Response Arrays 2-10
2.2.4. Study Characteristics That Will Be Considered in the Evaluation and Synthesis of
the Critical Studies for Hexavalent Chromium 2-11
3. PRELIMINARY EVIDENCE TABLES AND EXPOSURE-RESPONSE ARRAYS 3-1
3.1. Data Extraction for Animal Studies: Preparation of Preliminary Evidence Tables and
Exposure-Response Arrays 3-1
3.2. Respiratory System Effects 3-2
3.3. Gastrointestinal Effects 3-11
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
3.4. Liver Effects 3-16
3.5. Immune System and Lymphatic System Effects 3-26
3.6. Hematological Effects 3-35
3.7. Male Reproductive Effects 3-43
3.8. Female Reproductive Effects 3-51
3.9. Reproductive and Fetal Outcomes - Dosing Prior to Gestation 3-54
3.10. Reproductive and Fetal Outcomes - Dosing During Gestation Only 3-56
3.11. Offspring Outcomes - Dosing During Gestation and Lactation or Lactation Only 3-62
3.12. Carcinogenic Effects 3-67
REFERENCES 1
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
TABLES
Table 2-1. Database search strategy for hexavalent chromium 2-4
Table 2-2. Summary of additional search strategies for hexavalent chromium 2-6
Table 2-3. Animal studies with fundamental flaws not considered further in the assessment 2-8
Table 2-4. Animal studies considered less informative, not included in evidence tables but
retained as potential supporting information 2-10
Table 2-5. Questions and relevant experimental information for evaluation of experimental
animal studies 2-11
Table 3-1. Evidence pertaining to respiratory system effects following inhalation exposure to
hexavalent chromium 3-2
Table 3-2. Evidence pertaining to gastrointestinal (Gl) effects following oral exposure to
hexavalent chromium 3-11
Table 3-3. Evidence pertaining to liver effects following oral or inhalation exposure to
hexavalent chromium 3-16
Table 3-4. Evidence pertaining to immune and lymphatic system effects following oral or
inhalation exposure to hexavalent chromium 3-26
Table 3-5. Evidence pertaining to hematological effects following oral or inhalation exposure to
hexavalent chromium 3-35
Table 3-6. Evidence pertaining to male reproductive effects following oral or inhalation
exposure to hexavalent chromium 3-43
Table 3-7. Evidence pertaining to female reproductive organ effects following oral exposure to
hexavalent chromium 3-51
Table 3-8. Evidence pertaining to reproductive/fetal outcomes resulting from oral dosing prior
to gestation 3-54
Table 3-9. Evidence pertaining to reproductive/fetal outcomes resulting from oral dosing during
gestation only 3-56
Table 3-10. Evidence pertaining to offspring outcomes resulting from oral dosing during
gestation and lactation or lactation only3 3-62
Table 3-11. Evidence pertaining to carcinogenic effects following oral or inhalation exposure to
hexavalent chromium 3-67
FIGURES
Figure 2-1. Literature search approach for hexavalent chromium 2-3
Figure 3-1. Exposure-response array of respiratory system effects (BAL fluid) following
inhalation exposure to hexavalent chromium 3-9
Figure 3-4. Exposure-response array of liver effects following oral exposure to hexavalent
chromium. [A]: am3-C57BL/6 strain of mouse; [B]: B6C3F1; [C]: BALB/c 3-24
Figure 3-5. Exposure-response array of liver effects following inhalation exposure to hexavalent
chromium 3-25
Figure 3-6. Exposure-response array of immune and lymphatic system effects following oral
exposure to hexavalent chromium. [A]: am3-C57BL/6 strain of mouse; [B]:
B6C3F1; [C]: BALB/c 3-33
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Figure 3-7. Exposure-response array of immune and lymphatic system effects following
inhalation exposure to hexavalent chromium 3-34
Figure 3-8. Exposure-response array of hematological effects following oral exposure to
hexavalent chromium. [Kumar & B., 1991] denotes Kumar and Barthwal (1991).
[A]: am3-C57BL/6 strain of mouse; [B]: B6C3F1; [C]: BALB/c 3-41
Figure 3-9. Exposure-response array of hematological effects following inhalation exposure to
hexavalent chromium 3-42
Figure 3-10. Exposure-response array of male reproductive effects following oral exposure to
hexavalent chromium. [Chowdhury...l995] denotes Chowdhury & Mitra, 1995.
[A]: am3-C57BL/6 strain of mouse; [B]: B6C3F1; [C]: BALB/c 3-49
Figure 3-11. Exposure-response array of male reproductive effects following inhalation
exposure to hexavalent chromium 3-50
Figure 3-14. Exposure-response array of reproductive and fetal outcomes (dosing during
gestation only) following oral exposure to hexavalent chromium 3-66
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
ABBREVIATIONS
ACP acid phosphatase
ADAFs age-dependent adjustment factors
ALP alkaline phosphatase
ALT alanine aminotransferase
AST aspartate aminotransferase
ATSDR Agency for Toxic Substances and
Disease Registry
BAL bronchoalveolar lavage
CalEPA California Environmental Protection
Agency
CASRN Chemical Abstracts Service Registry
Number
CCA chromated copper arsenate
CPSC Consumer Product safety Commission
CrVI hexavalent chromium
E2 estradiol
EPA Environmental Protection Agency
FDA Food and Drug Administration
FRN Federal Registry Notice
FSH follicle-stimulating hormone
GD gestation day
GGT yglutarnyl transferase
GH growth hormone
GI gastrointestinal
GPT glutamic-pyruvate transaminase
HCT hematocrit
HERO Health and Environment Research
Online
Hgb hemoglobin
HSDB Hazardous Substance Data Bank
IARC International Agency for Research on
Cancer
IPCS International Programme on Chemical
Safety
IRIS Integrated Risk Information System
LDH lactate dehydrogenase
LH luteinizing hormone
MCH mean corpuscular hemoglobin
MCHC mean corpuscular hemoglobin
concentration
MCLG maximum contaminant level goal
MCV mean cell volume
MetHgb methemoglobin
MMAD mass median aerodynamic diameter
MMD mass median diameter
MRL minimum reporting level
NAS National Academy of Sciences
NATA National-Scale Air Toxics Assessment
NCEA National Center for Environmental
Assessments
NIOSH National Institute for Occupational
Safety and Health
NJ DEP New Jersey Department of
Environmental Protection
NOAEL no-observed-adverse-effect level
NPDWR National Primary Drinking Water
Regulation
NPL National Priorities List
NRC National Research Council
NTP National Toxicology Program
OPP Office of Pesticides Program
ORD Office of Research and Development
OSHA Occupational Safety and Health
Administration
P4 progesterone
PBPK physiologically based pharmocokinetic
PND postnatal day
PNW postnatal week
RBC red blood cell
RCRA Resource Conservation and Recovery
Act
RED reregistration eligibility decision
RfC reference concentration
RfD reference dose
RTF Research Triangle Park
SDH sorbitol dehydrogenase
SRBC sheep red blood cells
T testosterone
TRI Toxic Release Inventory
TSCATS Toxic Substances Control Act
Submission database
UCMR3 Third Unregulated Contaminant
Monitoring Rule
WBC white blood cell
WHO World Health Organization
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1
2 PREFACE
3 This draft document presents preliminary materials for an assessment of hexavalent
4 chromium (CrVI), prepared by EPA's Integrated Risk Information System (IRIS) Program. These
5 preliminary materials include a planning and scoping summary, problem formulation, information
6 on the approaches used to identify pertinent literature, results of the literature search, approaches
7 for selection of studies for hazard identification, and presentation of critical studies in evidence
8 tables and exposure-response arrays. This material is being released for public review and
9 comment prior to a public meeting, providing an opportunity for the IRIS Program to engage in
10 early discussions with stakeholders and the public on data that may be used to identify adverse
11 health effects and characterize dose-response relationships. This is the first of two sets of
12 preliminary materials for hexavalent chromium, and focuses on evidence from experimental animal
13 studies. A second set of preliminary materials will include evidence from human studies as well as
14 an inventory of toxicokinetic and mechanistic studies of hexavalent chromium.
15 The planning and scoping summary includes information on the uses of hexavalent
16 chromium, occurrence of hexavalent chromium in the environment, and the rationale for the
17 development of the assessment. This information is responsive to recommendations in the 2009
18 National Research Council (NRC) report Sc/ence and Decisions: Advancing Risk Assessment [NRG,
19 2009] related to planning and scoping in the risk assessment process.
20 Some problem formulation information is included to identify certain scientific elements or
21 data that will be important for developing the assessment This problem formulation information
22 identifies the human health effects that the assessment will evaluate and an analysis plan that
23 outlines the approaches envisioned for use in the assessment. The inclusion of problem
24 formulation also addresses the recommendations in the 2009 NRC report Science and Decisions:
25 Advancing Risk Assessment [NRC, 2009] related to problem formulation.
26 The preliminary materials are also responsive to the NRC 2011 report Review of the
27 Environmental Protection Agency's Draft IRIS Assessment ofFormaldehyde [NRC, 2011]. The IRIS
28 Program's implementation of the NRC recommendations is following a phased approach that is
29 consistent with the NRC's "Roadmap for Revision" as described in Chapter 7 of the formaldehyde
30 review report. The NRC stated that "the committee recognizes that the changes suggested would
31 involve a multi-year process and extensive effort by the staff at the National Center for
32 Environmental Assessment and input and review by the EPA Science Advisory Board and others."
33 Phase 1 of implementation has focused on a subset of the short-term recommendations, such as
34 editing and streamlining documents, increasing transparency and clarity, and using more tables,
35 figures, and appendices to present information and data in assessments. Phase 1 also focused on
36 assessments near the end of the development process and close to final posting. Phase 2 of
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 implementation is focused on assessments that are in the beginning stages of assessment
2 development The IRIS hexavalent chromium assessment is in Phase 2 and represents a significant
3 advance in implementing the NRC recommendations. In the development of this assessment, many
4 of the recommendations are being implemented in full, while others are being implemented in part
5 Achieving full and robust implementation of certain recommendations will be an evolving process
6 with input and feedback from the public, stakeholders, and independent external peer review.
7 Phase 3 of implementation will incorporate the longer-term recommendations made by the NRC,
8 including the development of a standardized approach to describe the strength of evidence for
9 noncancer effects. On May 16, 2012, EPA announced1 that as a part of a review of the IRIS
10 Program's assessment development process, the NRC will also review current methods for weight-
11 of-evidence analyses and recommend approaches for weighing scientific evidence for chemical
12 hazard identification. This effort is included in Phase 3 of EPA's implementation plan.
13 The literature search and screening strategy, which describes the processes for identifying
14 scientific literature, screening studies for consideration, and identifying pertinent sources of health
15 effects data, is responsive to NRC recommendations regarding the development of a systematic and
16 transparent approach for identifying the scientific literature for analysis. The preliminary materials
17 also describe EPA's approach for the selection of critical studies to be included in the evidence
18 tables, as well as the approach for evaluating methodological features of studies that will be
19 considered in the overall evaluation and synthesis of evidence for each health effect The
20 development of these materials is in response to the NRC recommendation to thoroughly evaluate
21 critical studies with standardized approaches that are formulated and based on the type of research
22 (e.g., observational epidemiology or animal bioassays). In addition, NRC recommendations for
23 standardized presentation of key study data are addressed by the development of the preliminary
24 evidence tables and exposure-response arrays for primary health effect information.
25 EPA welcomes all comments on the preliminary materials in this document, including the
26 following:
27 • the clarity and transparency of the materials;
28 • the approach for identifying pertinent studies;
29 • the selection of critical studies for data extraction to preliminary evidence tables and
30 exposure-response arrays;
31 • any methodological considerations that could affect the interpretation of or confidence
32 in study results; and
33 • any additional studies published or nearing publication that may provide data for the
34 evaluation of human health hazard or dose-response relationships.
35 The preliminary evidence tables and exposure-response arrays should be regarded solely as
36 representing the data on each endpoint that have been identified as a result of the draft literature
1 EPA Announces NAS' Review of IRIS Assessment Development Process. 05/16/2012.
http://yosemite.epa.gOV/opa/admpress.nsf/0/lce2a7875daf093485257a000054df5470penDocument
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 search strategy and approach to selecting critical studies. They do not reflect any conclusions as to
2 hazard identification or dose-response assessment.
3 After obtaining public input and conducting additional study evaluation and data
4 integration, EPA will revise these materials to support the hazard identification and dose-response
5 assessment in a draft Toxicological Review that will be made available for public comment
6
7
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1.INTRODUCTION
1 This introduction contains a planning and scoping summary and problem formulation for
2 the IRIS assessment of hexavalent chromium. The planning and scoping summary includes
3 information on the properties, sources and uses of hexavalent chromium, occurrence and fate of
4 hexavalent chromium in the environment, potential for human exposure, and the rationale for the
5 development of this assessment Problem formulation is a process used to identify certain scientific
6 elements or data that will be important for developing an assessment It helps EPA collect technical
7 and scientific input that will inform the development of that assessment The problem formulation
8 for hexavalent chromium uses the assessments by federal, state, and international health agencies
9 to identify scientific issues and studies that may inform EPA's plan for updating the inhalation and
10 oral cancer and noncancer assessment for hexavalent chromium.
11 1.1. Hexavalent Chromium in the Environment
12 1.1.1. Chemical and Physical Properties
13 Chromium is a transition metal element. It is present in the Earth's crust and has oxidation
14 states ranging from -2 to +6, with the +3 (trivalent) and +6 (hexavalent) states being the most
15 predominant. Hexavalent and trivalent chromium are also written as Cr(VI) and Cr(III),
16 respectively.
17 The solubility of chromium compounds depends primarily on the compound's oxidation
18 state and varies significantly. Most trivalent chromium compounds are insoluble in water. Some
19 hexavalent chromium compounds on the other hand, such as chromium oxide (or chromic acid),
20 and the ammonium and alkali metal salts (e.g., sodium and potassium) of chromic acid are readily
21 soluble in water. Hexavalent chromium is generally reduced to trivalent chromium in the
22 environment; however, hexavalent forms can persist under conditions where there is a low
23 concentration of reducing materials (ATSDR, 2012). Note that toxicity experiments for hexavalent
24 chromium use various compounds such as chromic acid, potassium dichromate, potassium
25 chromate and sodium chromate. Even though the physical properties of these compounds are
26 somewhat different, they are all ionized to hexavalent chromium in the body and are considered to
27 exert the same pharmacological and toxicological effects (U.S. EPA, 2008c).
28 1.1.2. Sources and Uses
29 Chromium can originate from both natural and man-made sources, but compounds
30 containing the hexavalent oxidation state primarily arise from anthropogenic sources, with the
31 largest releases occurring from industrial sources (ATSDR. 2012). The United States is one of the
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 world's leading producers of chromium compounds. Hexavalent chromium compounds are widely
2 used as corrosion inhibitors, in the manufacture of pigments, in metal finishing and chrome plating,
3 in stainless-steel production, in leather tanning, in wood preservatives, in textile dyeing processes,
4 printing inks, drilling muds, pyrotechnics, water treatment, chemical synthesis, and plastics.
5 Industries with the largest contribution to chromium release or disposal of chromium and
6 chromium compounds include metal processing, tannery facilities, chromate production, stainless
7 steel welding, electric utility companies, and ferrochrome and chrome pigment production [HSDB,
8 2014: U.S. EPA. 2014aj. In 1996, about 52% of chromium use in the United States was for the
9 production of wood preservatives [ATSDR, 2012], but this use has likely declined because of a 2003
10 voluntary phase-out of residential wood treated with chromated copper arsenate (CCA pressure-
11 treated wood] [CPSC. 20111.
12 1.1.3. Environmental Fate and Transport
13 Land
14 In 2012, environmental releases to land from domestic facilities required to report to EPA's
15 Toxics Release Inventory (TRI) Program totaled 7,760,131 Ibs of chromium and 44,373,397 Ibs of
16 chromium compounds. These accounted for over 90% of the total environmental releases of
17 chromium and chromium compounds reported to this inventory in 2012, and consisted of various
18 on- and offsite land releases including Resource Conservation and Recovery Act (RCRA) Subtitle C
19 landfills, other landfills and land disposals, underground injection, land treatments, and surface
20 impoundments [U.S. EPA, 2014a]. Chromium has been identified in samples from at least 1,127 of
21 1,699 NPL hazardous waste sites [ATSDR. 2012] and hexavalent chromium ranks 17th on ATSDR's
22 list of 275 hazardous substances (based on a combination of the chemical's frequency, toxicity, and
23 potential for human exposure at NPL sites].
24 The mobility of chromium in soil depends on the speciation of chromium, which is a
25 function of redox potential and the pH of the soil. In most soils, chromium will be present
26 predominantly in the trivalent oxidation state. This form has low solubility, thus generally resulting
27 in low mobility. Under oxidizing conditions, hexavalent chromium may be present in soil as Cr04~2
28 and HCrCU-, hexavalent forms that are relatively soluble and mobile. The leachability of hexavalent
29 chromium in the soil generally increases with soil pH (ATSDR, 2012].
30 Water
31 In 2012, environmental releases to water from domestic facilities required to report to the
32 TRI Program totaled 97,773 Ibs of chromium and 275,565 Ibs of chromium compounds. These
33 accounted for roughly 1% of the total environmental releases in 2012 of chromium and chromium
34 compounds in this inventory, and consisted of various on- and offsite releases to water including
35 surface water, wastewater treatment, and publicly owned treatment works (U.S. EPA. 2014a].
36 Chromium released into water is usually ultimately deposited in sediments. Transport of
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 chromium from water to the atmosphere is unlikely because of the extremely low volatility of
2 chromium compounds (ATSDR. 20121.
3 Most of the soluble chromium in the aqueous phase is present as hexavalent chromium or
4 as soluble trivalent chromium complexes. Reduction of hexavalent to trivalent chromium can occur
5 in the aquatic environment if an appropriate reducing agent is available. The most significant
6 reducing agents present in aquatic systems include (in order of decreasing reduction ability)
7 organic matter, hydrogen sulfide, sulfur, iron sulfide, ammonium, and nitrate. The reduction half-
8 life of hexavalent chromium in water can be rapid (instantaneously to a few days) when the right
9 reducing agents are present under anaerobic conditions, but can extend much longer in water with
10 soil and organic sediment, ranging from 4-140 days (ATSDR. 2012). Oxidation of trivalent to
11 hexavalent chromium can also occur in the aqueous environment, but hexavalent chromium
12 generally does not accumulate due to the concurrent presence of natural reductants. Speciation in
13 groundwater depends on the redox potential and pH conditions of the aquifer (ATSDR, 2012).
14 Chromium is predominantly present as trivalent chromium in surface water but as hexavalent
15 chromium in groundwaters (Frey etal., 2004). High groundwater levels of hexavalent chromium
16 have been reported in several areas in the Western US (California, Idaho and Arizona) (Mcneill et
17 al.. 20121.
18 Air
19 In the atmosphere, total chromium has been measured as small particulates (e.g., mass
20 mean aerodynamic diameter <10 |im) that can remain airborne for days and be transported over
21 long distances (ATSDR, 2012). Atmospheric particulate matter is deposited on land and water via
22 wet and dry deposition. Air emissions accounted for 2% or less of total environmental releases of
23 chromium and chromium compounds, respectively, from domestic facilities required to report to
24 the TRI Program in 2012 fU.S. EPA. 2014a1. These included 123,015 Ibs (fugitive) and 56,936 Ibs
25 (point source) of chromium, and 58,952 Ibs (fugitive) and 188,292 Ibs (pointsource) of chromium
26 compounds. It has been estimated that approximately one-third of the chromium emitted to the
27 atmosphere in the US is hexavalent chromium, and the estimated atmospheric half-life for
28 hexavalent chromium reduction to trivalent chromium ranges from 16 hours to 5 days (ATSDR,
29 20121.
30 1.1.4. Environmental Concentrations
31 The average atmospheric concentrations of total chromium compounds in the US based on
32 EPA's National Air Toxics Assessment (NATA) for 2005 was 0.009 ^g/m3 with a range of 0.00004-
33 0.02 [J.g/m3 (U.S. EPA, 2005a). Indoor air concentrations can be 10-400 times greater than outdoor
34 air concentrations when cigarette smoke is involved (ATSDR, 2012). In surveys of US surface
35 waters, total chromium concentrations in rivers ranged from <1-30 |J.g/L, and concentrations in
36 lakes typically were less than 5 [ig/L (ATSDR. 2012).
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 Bioaccumulation of chromium in plants appears to be unlikely, and there is no indication of
2 biomagnification of chromium along the terrestrial or aquatic food chain [ATSDR, 2012].
3 1.1.5. General Population Exposure
4 Human exposure to total chromium occurs from both natural and anthropogenic sources
5 [ATSDR, 2012]. Most human exposure to chromium is from dietary intake of trivalent chromium
6 that is naturally present in foods [Wisconsin DHS, 2010]. Trivalent chromium is generally
7 understood to be essential to normal glucose, protein, and fat metabolism and is thus an essential
8 dietary element with prescribed dietary reference intake guidelines [IOM, 2001], although some
9 investigators have questioned its essentiality to humans [Vincent, 2013: Stearns, 2000]. Typical
10 chromium levels in vegetables, fruits, grains, cereals, eggs, meat, and fish range from approximately
11 20 to 520 [J.g/kg [ATSDR. 2012]. Dermal exposure to chromium may also occur during the use of
12 consumer products that contain chromium, such as some metals and wood or leather treated with
13 chromium-containing compounds [ATSDR, 2012]. Chromium has been detected in various human
14 tissues and body fluids, including serum, urine, lung, breast milk, hair, and nails [ATSDR, 2012].
15 The general population may be exposed to hexavalent chromium compounds via inhalation
16 of ambient air, ingestion of water or food, or dermal contact with chromium-containing products
17 such as pressure-treated wood [NTP. 2011]. Elevated exposures to hexavalent chromium may
18 occur among individuals who live near industrial facilities that use hexavalent chromium or near
19 sites where chromium compounds have been disposed [NTP, 2011]. However, human exposure
20 studies generally do not identify the specific forms of chromium [NTP, 2011]. Children's exposure
21 to chromium from ingestion of soil or from contact with playground equipment constructed with
22 chromated copper arsenate (CCA]-treated wood is of potential concern [ATSDR, 2012: Hamula et
23 al.. 2006].
24 Monitoring data indicate that exposure to hexavalent chromium can occur through drinking
25 water. In 341 drinking water samples taken across 41 states where the total chromium mean level
26 was 1.9 [ig/L, hexavalent chromium levels ranged from 0-52.6 [ig/L (mean, 1.1 [J.g/L], with 57% of
27 samples reporting non-detectable concentrations [Seidel etal., 2012: Frey etal., 2004]. Data from
28 the California Department of Public Health indicate that 87% of samples (n=27,507] in that state
29 had concentrations of hexavalent chromium above the minimum reporting level (MRL] of 1 |ig/L
30 [Seidel etal., 2012]. It may be noted that accurate speciation methods for measuring low levels of
31 hexavalent chromium are very recent, accounting for the relative paucity of monitoring data for
32 hexavalent chromium [Mcneill etal.. 2012]. EPA's Third Unregulated Contaminant Monitoring Rule
33 (UCMR3] Program is working with states to test systems during 2012-2015 for the presence of
34 total chromium and hexavalent chromium; results through January 2014 indicate that 76% of the
35 samples have hexavalent chromium concentrations greater than a MRL of 0.03 [ig/L and 90% of the
36 public water systems had hexavalent chromium concentrations greater than 0.03 [ig/L [U.S. EPA,
37 2014b]. Hexavalent chromium in water distribution systems can also occur as a disinfection by-
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 product because of the efficient oxidation of trivalent chromium by chlorine and other agents such
2 as ozone and permanganate used in disinfection and odor removal [Mcneilletal., 2012].
3
4 1.2. Scope of the Assessment
5 Significant new epidemiologic and experimental animal toxicity information for hexavalent
6 chromium has become available since EPA's current IRIS assessment for hexavalent chromium was
7 posted in 1998, including updates of earlier occupational cohort studies and a National Toxicology
8 Program bioassay that reported increased incidences of tumors in rats and mice exposed to
9 hexavalent chromium in drinking water [NTP, 2008]. The NTP [2008] bioassay findings are
10 significant because they provide the first direct laboratory evidence of carcinogenicity for ingested
11 hexavalent chromium. Further, the dose-response information from both new epidemiologic and
12 experimental animal studies could result in changes to current toxicity values. Given the
13 widespread exposure to hexavalent chromium and the availability of new studies that provide
14 significant new health effects information, the IRIS Program is developing an updated assessment
15 of hexavalent chromium. This updated assessment will address multiple Agency needs. Several
16 regulatory programs and activities that would benefit from a more current IRIS assessment of
17 hexavalent chromium are presented below:
18
19 • Hexavalent chromium has been identified as a contaminant of concern at numerous
20 contaminated waste sites, including more than a thousand National Priority List (NPL] sites.
21 IRIS values are used to develop screening values at NPL sites and to set remediation targets
22 for contaminated sites.
23 • In its 2008 Omnibus Appropriations Bill, Congress asked EPA to develop an updated health
24 standard for ingested hexavalent chromium, and use this standard to revise the maximum
25 contaminant level for drinking water as soon as possible. The EPA Administrator indicated
26 her commitment to developing a health assessment and a potential regulation for
27 hexavalent chromium in drinking water during her testimony before the Senate
28 Environment and Public Works Committee in 2010. An updated IRIS assessment for
29 hexavalent chromium will be directly responsive to Congressional language and to the
30 Administrator's commitment to developing a health assessment for hexavalent chromium.
31 • Currently, the EPA drinking water standard of 0.1 milligrams per liter (mg/L] is for total
32 chromium, which includes all forms of chromium including hexavalent chromium [Federal
33 Register. 2010]. This standard is based on a 1-year drinking water study of hexavalent
34 chromium in rats [MacKenzie etal.. 1958]. The Safe Drinking Water Act requires EPA to
35 periodically review the national primary drinking water regulation [NPDWR] for each
36 contaminant and revise the regulation, if appropriate. Following its second six-year review
37 announced in 2010, EPA noted that it would await the updated IRIS assessment for
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 hexavalent chromium in order to evaluate revising the NPDWR. The Agency anticipates
2 completing the next review of the NPDWRs by 2016.
3 • Chromium compounds are also listed among the original hazardous air pollutants
4 (sometimes referred to as air toxics) under the Clean Air Act. The health risks associated
5 with air toxics, including chromium compounds, are assessed under the National-Scale Air
6 Toxics Assessment (NATA), EPA's ongoing comprehensive evaluation of air toxics in the U.S.
7 NATA provides estimates of cancer and noncancer health effects based on chronic
8 inhalation exposure from outdoor sources, and is used to identify and prioritize air toxics,
9 emission source type, and locations that are of greatest potential concern in terms of
10 contributing to population risk. IRIS values are used in assessing population risks (U.S. EPA,
11 2005aj.
12
13 Accordingly, this IRIS assessment will address the needs of EPA's program and regional
14 offices by identifying the health hazards from exposure to hexavalent chromium via inhalation and
15 ingestion and by deriving toxicity values for these health hazards. The updated IRIS assessment
16 will not address potential health effects from dermal exposures because EPA's Office of Pesticide
17 Programs (OPP) previously evaluated this exposure pathway in its reregistration eligibility decision
18 (RED) for CCA pesticides (U.S. EPA, 2008c) and no priority needs related to dermal exposure have
19 been identified by other EPA program and regional offices.
20
21 1.3. Problem Formulation
22 1.3.1. Assessments by Federal, State, and International Health Agencies
23 EPA's current IRIS assessment of hexavalent chromium was completed in 1998 (U.S. EPA,
24 1998). In order to identify studies and scientific issues that may impact an updated IRIS
25 assessment of hexavalent chromium, EPA consulted the following assessments subsequently
26 published by federal, state, or international health agencies, with an emphasis on more recent
27 documents:
28
29 1. International Programme of Chemical Safety (IPCS). (2013). Inorganic chromium(VI)
30 compounds. (78). Geneva, Switzerland: World Health Organization.
31 2. National Institute for Occupational Safety and Health (NIOSH). (2013). Occupational
32 exposure to hexavalent chromium. (DHHS (NIOSH) Publication No. 2013-128). Department
33 of Health and Human Services, Centers for Disease Control and Prevention.
34 3. Agency for Toxic Substances and Disease Registry (ATSDR). (2012). Toxicological profile for
35 chromium. Atlanta, GA: US Department of Health and Human Services, Public Health
36 Service.
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 4. International Agency for Research on Cancer (IARC). [2012]. A review of human
2 carcinogens: Arsenic, metals, fibres, and dusts [IARC Monographs Volume 100C]. Lyon,
3 France.
4 5. California EPA (Cal/EPA). [20111. Public health goal for Hexavalent Chromium (Cr VI) in
5 drinking water. Sacramento, CA: Pesticide and Environmental Toxicology Branch, Office of
6 Environmental Health Hazard Assessment.
7 6. National Toxicology Program (NTP). [2011]. Report on carcinogens: Twelfth edition (12th
8 ed.]. Research Triangle Park, NC.
9 7. New Jersey Department of Environmental Protection (NJ DEP]. [2009]. Derivation of
10 ingestion-based soil remediation criterion for Cr+6 based on the NTP chronic bioassay data
11 for Sodium Dichromate Dihydrate.
12 8. U.S. EPA. [2008a. b). Evaluation of the carcinogenic potential of inorganic hexavalent
13 chromium (Cr(VI]]. Washington, DC: Health Effects Division, Office of Pesticide Programs.
14 9. Food and Drug Administration (FDA]. (2013]. Beverages: Bottle water. Code of Federal
15 Regulations: 21 CFR 165.110.
16 10. Occupational Safety and Health Administration (OSHA]. (2006]. Occupational exposure to
17 hexavalent chromium. Final rule. Fed Reg 71: 10099-10385.
18 11. World Health Organization (WHO]. (2003]. Chromium in drinking water.
19 (WHO/SDE/WSH/03.04/04]. Geneva, Switzerland.
20 12. U.S. EPA. (2009]. National primary drinking water regulation [EPA Report]. (EPA/816/F-
21 09/004]. Washington, DC.
22 13. The Netherlands National Institute for Public Health and the Environment (RIVM). (2001].
23 Re-evaluation of human-toxicological maximum permissible risk levels (pp. 58-61]. (RIVM
24 report 711701 025]. Bilthoven, the Netherlands: Rijksinstituutvoor Volksgezondheid en
25 Milieu RIVM.
26 1.3.2. Toxicokinetics of Hexavalent Chromium
27 IPCS(2013]. ATSDR(2012]. Cal/EPA (2011] and OSHA (2006] have reviewed the
28 absorption and metabolism of hexavalent chromium. Briefly, chromium exists in multiple oxidation
29 states, but it is the hexavalent and trivalent states that are most prevalent biologically. Following
30 oral or inhalation exposure (and prior to systemic absorption], hexavalent chromium can be
31 reduced to trivalent chromium within the gastrointestinal (GI] tract or the respiratory tract,
32 respectively. If reduced to the trivalent state prior to uptake, chromium is poorly absorbed by cells.
33 However, chromium in the hexavalent state can be readily absorbed by cells lining the GI or
34 respiratory tract Systemically absorbed hexavalent chromium is rapidly absorbed and reduced by
35 cells in the body. The reverse of this process, oxidation of trivalent chromium to hexavalent
36 chromium, will not occur in the body. As a result, systemically circulating chromium is believed to
37 exist primarily in the trivalent state, particularly since red blood cells can efficiently reduce
38 hexavalent chromium to trivalent chromium.
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 IPCSf2013] and ATSDRf2012] raised the issue of extrapolating data on hexavalent
2 chromium toxicity, including tumor response, from orally exposed animals to humans in light of the
3 toxicokinetic properties of hexavalent chromium. The National Toxicology Program (NTP) rodent
4 bioassay reported tumors in the oral cavity in rats and the small intestine in mice, as well as GI tract
5 effects other than cancer, following chronic drinking water exposure to hexavalent chromium. GI
6 toxicokinetics following oral exposure influences the amount of ingested hexavalent chromium that
7 is subsequently absorbed by GI mucosae, and therefore the potential for hexavalent chromium to
8 induce GI toxicity. In particular, inter- and intraspecies differences in reductive capacities or in
9 rates of reduction of ingested hexavalent chromium may exist that could impact the extrapolation
10 of rodent bioassay data to humans and the identification of potential susceptible subpopulations.2
11 The updated assessment is expected to take into consideration the available hexavalent chromium
12 toxicokinetic data in the quantitative analysis of oral toxicity data.
13 1.3.3. Cancer - inhalation route
14 EPA's 1998 IRIS assessment classified hexavalent chromium as "Group A - known human
15 carcinogen by the inhalation route of exposure" based on evidence of a causal relationship between
16 inhalation of hexavalent chromium and increased incidence of lung cancer in humans. The same
17 conclusion has been reached by other federal and state health agencies and international
18 organizations flPCS. 2013: NIOSH. 2013: IARC. 2012: Gal/EPA. 2011: NTP. 2011: OSHA. 20061 the
19 most recent of which was published in 2013. Consistent with this international consensus, the new
20 studies published since 1998 do not contain results that would change EPA's conclusion to
21 characterize hexavalent chromium as a human carcinogen via the inhalation route. Therefore, this
22 assessment will focus on the review of the evidence for lung cancer to identify studies that might
23 improve the quantitative dose-response analysis for human lung cancer.
24 EPA's 1998 IRIS assessment included an inhalation unit risk for hexavalent chromium based
25 on increased incidence of lung cancer in chromate workers as reported in an epidemiologic study
26 by Mancuso [1997,1975]. Since that time, several other organizations have derived inhalation
27 toxicity values for hexavalent chromium based on more recent epidemiologic studies:
28 • IPCS T20131 - linearly extrapolated lung cancer risk based on Gibb et al. f20001
2 Because of the importance of evaluating all existing information on this topic, EPA convened a public
workshop webinar on this topic on September 19 and 25, 2013. A panel of scientists discussed the available
studies of extracellular reduction, absorption, and transit in the GI tract for metals in general and hexavalent
chromium in particular. Some of the panelists were experts on hexavalent chromium reduction and toxicity,
and were able to provide valuable insight into toxicokinetic studies. Other panelists had expertise in GI tract
physiology, GI toxicokinetic modeling, toxicology, and epidemiology. The aim of the workshop was not to
have the panel reach consensus on any particular topic, but to foster discussion across the different areas of
expertise and viewpoints so that both EPA and the public could become better informed of the issues.
Workshop materials can be obtained atwww.epa.gov/iris/irisworkshops/cr6.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 • NIOSH [2013] - Recommended Exposure Limit (REL) based on lung cancer data from Gibb
2 etal. f2000j
3 • Gal/EPA [2011] - slope factor based on lung cancer data from Gibb etal. [2000]
4 • OSHA [2006] - Permissible Exposure Level [PEL] based on lung cancer data from Gibb et al.
5 [2000]
6 Furthermore, some of these assessments have discussed mechanistic studies investigating the role
7 of hexavalent chromium mutagenicity and/or genotoxicity in the induction of lung tumors [IARC.
8 2012: NTP. 2011: OSHA. 2006]. A mutagenic mode of action for chemical-induced carcinogenicity
9 is considered relevant to all populations and lifestages. The current understanding of biology of
10 cancer indicates that mutagenic chemicals are expected to exhibit a greater effect in early life
11 exposure versus later life exposure [U.S. EPA, 2005b].
12 Due to the availability of new data and approaches that may substantially change EPA's
13 1998 inhalation toxicity value for carcinogenic effects, EPA plans to update the dose-response
14 assessment for the carcinogenic effects of inhalation exposure to hexavalent chromium. This
15 update is expected to include the following:
16 • A systematic review of epidemiologic studies for the purpose of identifying studies suitable
17 for deriving point(s] of departure for hexavalent chromium-induced lung cancer.
18 • Analysis of available data on toxicity pathways/modes of action for lung cancer induced by
19 hexavalent chromium inhalation for the purposes of:
20 o Supporting the choice of linear and/or non-linear extrapolation from the point(s] of
21 departure for this endpoint.
22 o Identifying potentially susceptible subpopulations or lifestages.
23 o Determining if a mutagenic mode of action is operative, and therefore whether to
24 apply age-dependent adjustment factors [ADAFs] to account for early-life
25 susceptibility to carcinogenic effects after inhalation of hexavalent chromium.
26 • Dose-response analyses to derive point(s] of departure and toxicity value[s] (inhalation
27 unit risk and/or reference concentrations] for hexavalent chromium-induced lung cancer.
28 1.3.4. Cancer - oral route
29 EPA's 1998 IRIS assessment concluded that carcinogenicity of hexavalent chromium "by the
30 oral route of exposure cannot be determined and is classified as Group D." A toxicity value was not
31 derived for this endpoint Subsequent reviews by EPA and state agencies have noted that
32 experiments in rodents conducted by NTP [2008] reported increased incidences of cancers after
33 oral administration [Gal/EPA. 2011: NTP. 2011: NT PEP. 2009: U.S. EPA. 2008b]. Several of these
34 reviews present oral toxicity values for hexavalent chromium-induced cancer based on these
35 rodent studies:
36 • Gal/EPA [2011] - oral slope factor based on incidences of adenomas and carcinomas in the
37 small intestine of male mice [NTP. 2008]
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 • NT PEP [2009] - oral slope factor based on incidences of adenomas and carcinomas in the
2 small intestine of male mice [NTP. 2008]
3 • U.S. EPA [2008b] - oral slope factor based on incidences of adenomas and carcinomas in the
4 small intestine of female mice [NTP. 2008]
5 Additionally, some of these assessments have discussed mechanistic studies investigating the role
6 of hexavalent chromium mutagenicity and/or genotoxicity in inducing these cancers [IPCS. 2013:
7 Gal/EPA. 2011: NT PEP. 2009: U.S. EPA. 2008b). A mutagenic mode of action for chemical-induced
8 carcinogenicity is considered relevant to all populations and lifestages. The current understanding
9 of biology of cancer indicates that mutagenic chemicals are expected to exhibit a greater effect in
10 early life exposure versus later life exposure [U.S. EPA. 2005b]. Furthermore, as discussed above,
11 information on inter- and intraspecies toxicokinetic differences, particularly with respect to
12 reduction of hexavalent chromium to trivalent chromium in the GI tract, may be important to
13 consider in assessing the human health hazard for cancer after ingestion of hexavalent chromium.
14 Due to the availability of new data that may substantially change EPA's 1998 conclusions
15 regarding cancer classification and dose-response, EPA plans to update its hazard identification and
16 dose-response assessment of hexavalent chromium carcinogenicity by ingestion. This update is
17 expected to include the following:
18 • Systematic review of available studies for the purposes of:
19 o Conducting a weight-of-evidence analysis for the carcinogenicity of ingested
20 hexavalent chromium.
21 o Identifying studies and endpoints suitable for dose-response analysis.
22 • Analysis of available toxicokinetic data to evaluate whether toxicologically-relevant inter-
23 and/or intraspecies differences in toxicokinetics, particularly with respect to reduction of
24 hexavalent chromium to trivalent chromium in the GI tract, can be estimated quantitatively.
25 • Analysis of available data on toxicity pathways/modes of action for cancers induced by
26 hexavalent chromium ingestion for the purposes of:
27 o Supporting conclusions as to the human relevance of cancers induced in rodents by
28 ingested hexavalent chromium.
29 o Supporting the choice of linear and/or non-linear extrapolation from the point(s] of
30 departure for this endpoint, if there is a cancer hazard by ingestion.
31 o Identifying potentially susceptible subpopulations or lifestages, if there is a cancer
32 hazard by ingestion.
33 o Determining if a mutagenic mode of action is operative, and therefore whether to
34 apply ADAFs to account for early-life susceptibility to carcinogenic effects after
35 ingestion of hexavalent chromium, if there is a cancer hazard by ingestion.
36 • Dose-response analyses to derive point(s] of departure and toxicity value(s] (oral slope
37 factor and/or reference dose] for carcinogenic effects after ingestion of hexavalent
38 chromium.
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 1.3.5. Noncancer effects
2 EPA's 1998 IRIS assessment derived a reference concentration (RfC) for noncancer effects
3 based on nasal effects (from chromic acid mists and dissolved hexavalent chromium aerosols) in a
4 subchronic epidemiologic study [Lindberg and Hedenstierna, 1983] and respiratory tract effects
5 (from hexavalent chromium particulates) in subchronic rat studies (Malsch et al.. 1994: Glaser etal..
6 1990]. EPA's 1998 IRIS assessment also derived a reference dose (RfD] for noncancer effects based
7 on a NOAEL reported in a 1-year drinking water study in rats (MacKenzie etal., 1958]. Since that
8 time, NTP (2008] has conducted a comprehensive toxicity bioassay of the effects of orally
9 administered hexavalent chromium in rodents. Additionally, subsequent reviews by government
10 health agencies and international health organizations have identified a number of potential targets
11 of toxicity from inhalation or ingestion of hexavalent chromium, including:
12 • Respiratory effects. IPCS (2013]. NIOSH (2013]. ATSDR (2012] and OSHA (2006] all
13 reported respiratory effects in workers via inhalation. These included chronic rhinorrhea,
14 nasal itching and soreness, nasal mucosal atrophy, epistaxis, perforations and ulceration of
15 the nasal septum, bronchitis, pneumonoconiosis, decreased pulmonary function, and
16 pneumonia. Animal data on respiratory effects were reported by IPCS (2013] and ATSDR
17 (2012], including nasal septum perforation, hyperplasia and metaplasia of the larynx,
18 trachea, and bronchus, epithelial necrosis of the bronchiolar walls, hyperplasia and fibrosis,
19 inflammation, impaired lung function and emphysema. In bronchoalveolar lavage (BAL]
20 fluid, increased percentage of lymphocytes, increases in the levels of total protein, albumin,
21 and activity of lactate dehydrogenase and (3-glucuronidase were reported.
22 • Gastrointestinal effects. ATSDR (2012] reviewed reports of oral ulcer, diarrhea,
23 abdominal pain, indigestion, and vomiting in people who consumed hexavalent chromium-
24 contaminated well water. Gastrointestinal effects in rats and mice, reviewed by IPCS
25 (2013]. ATSDR (2012]. and Gal/EPA (2011]. included duodenal histiocytic infiltration,
26 epithelial hyperplasia of the duodenum, and ulcer and epithelial hyperplasia and metaplasia
27 of the glandular stomach.
28 • Hepatic effects. ATSDR (2012] reviewed liver toxicity observed in case reports of humans
29 exposed to hexavalent chromium by ingestion. Liver damage was evidenced by the
30 development of jaundice, increased bilirubin, and increased serum lactate dehydrogenase
31 and liver enzymes. Hepatic effects in animals, as summarized by ATSDR (2012] and
32 Gal/EPA (2011], included increased serum alanine aminotransferase (ALT] and sorbital
33 dehydrogenase (SDH] activity and histopathological changes (including cellular histiocytic
34 infiltration, chronic focal inflammation, cytoplasmic vacuolization, increased sinusoidal
35 space, fatty changes, clear cell and eosinophilic foci, and necrosis].
36 • Hematological effects. IPCS (2013]. ATSDR (2012]. and Gal/EPA (2011] summarized
37 hematological effects observed in animal studies, including microcytic, hypochromic
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 anemia, characterized by decreased mean cell volume (MCV), mean corpuscular
2 hemoglobin (MCH), hematocrit (Hct), and hemoglobin (Hgb).
3 • Immunological effects. IPCS [20131. NIOSH [20131. ATSDR [20121. and OSHA [20061
4 summarized data on asthma attacks in some sensitized workers, indicating immunological
5 effects in humans. Additionally, functional and histopathological changes to the immune
6 system in animals were reviewed by ATSDR [20121 and Gal/EPA [20111. These effects
7 included stimulation of the humoral immune system and increased phagocytic activity of
8 macrophages, increased proliferative responses of splenocytes, and histiocytic cellular
9 infiltration of pancreatic lymph nodes.
10 • Reproductive effects. IPCS (2013). NIOSH (2013). and ATSDR T20121 summarized data on
11 reproductive effects in workers, including increases in the number of morphologically
12 abnormal sperm, decreases in sperm count and motility, and greater incidences of
13 complications during pregnancy and childbirth (toxicosis and postnatal hemorrhage).
14 Reproductive effects in monkeys, rats and rabbits, reviewed by ATSDR (2012) and Cal/EPA
15 (2011), included decreased sperm count and motility and histopathological changes to the
16 epididymis (ductal obstruction, development of microcanals, depletion of germ cells,
17 hyperplasia of Leydig cells, and Sertoli cell fibrosis). Changes in sexual behavior in rats and
18 mice were also reported.
19 • Developmental effects. ATSDR (2012) and Cal/EPA (2011) reviewed developmental
20 effects observed in rats and mice. Exposure to hexavalent chromium premating and/or in
21 utero or during lactation was associated with increased postimplantation loss, decreased
22 number of live fetuses/litter, decreased fetal weight, internal and skeletal malformations,
23 and delayed sexual maturation in offspring.
24
25 Additionally, several of these reviews derived chronic inhalation or oral toxicity values, some of
26 which are based on studies more recent than EPA's 1998 IRIS assessment:
27
28 • IPCS [20131 and ATSDR [20121 - inhalation toxicity value based on nasal irritation from
29 chromic acid/chromium trioxide (Lindberg and Hedenstierna, 1983)
30 • IPCS (2013) - inhalation toxicity value based on altered lactate dehydrogenase activity in
31 BAL fluid from salts of hexavalent chromium (Glaser etal., 1990)
32 • IPCS (2013) and ATSDR (2012) - oral toxicity value based on diffuse epithelial hyperplasia
33 in the duodenal mucosa of female mice (NTP. 2008)
34 • Cal/EPA (2011) - oral toxicity value based on mild chronic inflammation and fatty changes
35 in the liver of female mice (NTP. 2008)
36 • RIVM (2001) - oral toxicity value based on noncarcinogenic effects (not specified) from
37 MacKenzie et al. (1958) study.
38
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 Finally, as discussed above in the Section Toxicokinetics ofhexavalent chromium,
2 information on inter- and intraspecies toxicokinetic differences, particularly with respect to
3 reduction of hexavalent chromium to trivalent chromium in the gastrointestinal tract, will be
4 important to consider in assessing the noncancer toxicity of ingested hexavalent chromium.
5 Therefore, due to the availability of new data that may substantially change EPA's 1998
6 conclusions as to the noncancer toxicity of inhaled or ingested hexavalent chromium (including the
7 RfC and RfD), EPA will be conducting an update of its hazard identification and dose-response
8 assessment of hexavalent chromium noncancer toxicity. Because of the availability of multiple
9 recently completed comprehensive reviews of the noncancer health effects ofhexavalent
10 chromium, the IRIS assessment will focus its hazard identification and dose-response assessment
11 on the health effects identified above: respiratory, gastrointestinal, hepatic, hematological,
12 immunological, reproductive, and developmental. These cover both the "primary health effects
13 associated with exposure to hexavalent chromium" identified by ATSDR[2012] and the health
14 effects that have been used as the basis of noncancer toxicity values. In sum, this update is expected
15 to include the following:
16 • Systematic review of available studies for the purposes of:
17 o Conducting a weight-of-evidence analysis for identifying the noncancer respiratory,
18 gastrointestinal, immunological, hepatic, hematological, reproductive, and
19 developmental hazards of inhaled or ingested hexavalent chromium.
20 o Identifying studies and endpoints among these hazards suitable for dose-response
21 analysis.
22 • Analysis of available toxicokinetic data to evaluate whether toxicologically-relevant inter-
23 and/or intraspecies differences in toxicokinetics, particularly with respect to reduction of
24 hexavalent chromium to trivalent chromium in the gastrointestinal tract, can be estimated
25 quantitatively.
26 • Analysis of available data on toxicity pathways/modes of action for noncancer effects
27 induced by hexavalent chromium inhalation or ingestion for the purposes of:
28 o Supporting conclusions as to the human relevance of noncancer effects induced in
29 rodents by inhaled or ingested hexavalent chromium.
30 o Identifying potentially susceptible subpopulations or lifestages.
31 • Dose-response analyses to derive point(s) of departure and toxicity value (s) (RfCs and
32 RfDs) for noncancer effects after inhalation or ingestion ofhexavalent chromium.
33 Evaluation of the feasibility of dose-response analysis of noncancer effects to support
34 economic benefits analyses.
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1
2.METHODS FOR IDENTIFYING AND SELECTING
STUDIES
2 The NRG [2011] recommended that EPA develop a detailed search strategy utilizing a
3 graphical display documenting how initial search findings are narrowed to the final studies that are
4 selected for further evaluation on the basis of defined inclusion and exclusion criteria. Following
5 these recommendations, a literature search and screening strategy were used to identify literature
6 characterizing the health effects of hexavalent chromium. This strategy consisted of a search of
7 online scientific databases and other sources, casting a wide net in order to identify all potentially
8 pertinent studies. In subsequent steps, references were screened to exclude papers not pertinent
9 to an assessment of the health effects of hexavalent chromium, and remaining references were
10 sorted into categories for further evaluation. Section 2.1 describes the literature search and
11 screening strategy in detail.
12 The NRG [2011] further recommended that after studies are identified for review by
13 utilizing a transparent search strategy, the next step is to summarize the details and findings of the
14 most pertinent studies in evidence tables. The NRC suggested that such tables should provide a link
15 to the references, and include details of the study population, methods, and key findings. This
16 approach provides for a systematic and concise presentation of the evidence. The NRC also
17 recommended that the methods and findings should then be evaluated with a standardized
18 approach. The approach that was outlined identified standard issues for the evaluation of
19 epidemiological and experimental animal studies. Section 2.2 describes the approach taken for
20 hexavalent chromium for selecting studies to be included in preliminary evidence tables and
21 exposure-response arrays. Section 3 presents the selected studies in preliminary evidence tables
22 and exposure-response arrays, arranged by health effect
23 2.1. Draft Literature Search and Screening Strategy
24 The literature search for hexavalent chromium was conducted in four online scientific
25 databases, including PubMed, Toxline, Web of Science, and TSCATS, in January 2013; the search was
26 repeated in July 2013 and in January 2014. The detailed search approach, including the search
27 strings and number of citations identified per database, is presented in Table 2-1. This search of
28 online databases identified 9,721 citations (after electronically eliminating duplicates]. The
29 computerized database searches were also supplemented by a manual search of citations from
30 other regulatory documents (Table 2-2]; 99 citations were obtained using these additional search
31 strategies. In total, 9,820 citations were identified using online scientific databases and additional
32 search strategies.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 These citations were screened using the title, abstract, and in limited instances, full text for
2 pertinence to examining the health effects of hexavalent chromium exposure. The process for
3 screening the literature is described below and is shown graphically in Figure 2-1.
4 • 168 references were identified as potential sources of chronic health effects data and
5 were considered for data extraction into evidence tables and exposure-response arrays.
6 • 1,773 studies were identified as supporting studies; these included 127 studies
7 describing physiologically-based pharmacokinetic (PBPK) models and other
8 toxicokinetic information, 805 studies providing genotoxicity and other mechanistic
9 information, 733 dermal, acute, short-term, injection, and intratracheal instillation
10 exposure studies, and 108 human case reports. While still considered sources of health
11 effects information, studies investigating dermal, acute, short-term, injection, and
12 intratracheal instillation exposures and case reports are generally less pertinent for
13 characterizing health hazards associated with chronic oral and inhalation exposure.
14 Therefore, information from these studies was not considered for extraction into the
15 preliminary evidence tables. Nevertheless, these studies will still be evaluated as
16 possible sources of supporting health effects information.
17 • 466 references were identified as secondary sources of health effects information (e.g.,
18 reviews and other agency assessments); these references were kept as additional
19 resources for development of the Toxicological Review.
20 • 786 references were kept for further review. This category includes references that did
21 not provide enough material to evaluate pertinence (e.g., abstract not available) and
22 foreign language studies.
23 • 6,627 references were identified as not being pertinent to an evaluation of the health
24 effects of hexavalent chromium and were excluded from further consideration (see
25 Figure 2-1 for exclusion categories).
26 The literature will be regularly monitored for the publication of new studies and a formal
27 updated literature search and screen will be conducted after the IRIS bimonthly public meeting
28 discussing these preliminary materials. The documentation and results for the literature search
29 and screen can be found on the Health and Environmental Research Online (HERO) website
30 (http://hero.epa.gov/index.cfm?action=landing.main&project id=2233).3
3 HERO (Health and Environmental Research On-line) is a database of scientific studies and other references
used to develop EPA's risk assessments aimed at understanding the health and environmental effects of
pollutants and chemicals. It is developed and managed in EPA's Office of Research and Development (ORD)
by the National Center for Environmental Assessment (NCEA). The database includes more than 300,000
scientific articles from the peer-reviewed literature. New studies are added continuously to HERO.
Note: The HERO database will be regularly updated as additional references are identified during assessment
development. Therefore, the numbers of references (by tag) displayed on the HERO webpage for hexavalent
chromium may not match the numbers of references identified in Figure 3-1 (current through April 2014).
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Database Searches
see Table 2-1 for keywords and limits)
Pubmed
n=4,863
Web of Science
n=4,964
n=5,299
TSCA 2
(After duplicates removed electronically)
n=9,721
Additional Search Strategies
(see Table 2-2 for methods and results)
n=99
Combined Dataset
(After all duplicates removed)
n=9,820
Manual Screening For Pertinence
(Title/Abstract/Full Text)
1
2
Excluded (not pertinent) (n=6,627)
303 Non peer-reviewed
121 Exposure
306 Ecology
882 No toxicology keywords
5015 Other not pertinent
Sources of Health Effects
Data (n=168)*
109 Human health effects
studies
60 Animal studies
' One study (Li etal. 2000) is
categorized in animal and human.
Kept for Further Review (n=786)
631 Foreign language
155 Abstract only
Supporting Studies
(n=l,773)
127 PBPK/ADME
457 Genotoxicity
348 Other mechanistic
studies
626 Dermal studies
33 Acute/short-term
studies
74 Injection or
intratracheal studies
108 Human case reports
Secondary Sources of
Health Effects
Information (n=466)
231 Reviews
29 Other agency
assessments
46 Other studies
161 Other Cr compounds
(e.g., metal
chromates)
Figure 2-1. Literature search approach for hexavalent chromium.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Table 2-1. Database search strategy for hexavalent chromium
Database
(Search Date)
Keywords
Limits
PubMed
(1/29/2013)
(7/19/2013)
(2/5/2014)
hexavalent chromium OR (hexavalent AND
chromium) OR CRVI OR CR VI OR Chromium VI
OR "Chromic acid" OR "Calcium chromate" OR
"Potassium dichromate" OR "Potassium
chromate" OR "Sodium chromate" OR "lead
chromate" OR "zinc chromate" OR "strontium
chromate" OR "ammonium dichromate" OR
13765-19-0[RN] OR 1333-82-0[RN] OR 7789-00-
6[RN] OR 7778-50-9[RN] OR 7775-ll-3[RN] OR
7789-12-0[RN] OR 13530-65-9[RN] OR 7738-94-
5[rn] OR 18540-29-9[rn] OR 7758-97-6[RN] OR
11119-70-3[rn] OR 11103-86-9[rn] OR 13530-
65-9[rn] OR 7788-98-9[rn] OR 77898-09-5[rn]
OR 7789-06-2[rn]
None
Web of Science
(1/29/2013)
(7/19/2013)
(2/5/2014)
Topic = (hexavalent chromium OR (hexavalent
AND chromium) Chromium VI OR CrVI OR Cr VI
OR "Chromic acid" OR "Calcium chromate" OR
"Chromic trioxide" OR "Potassium dichromate"
OR "Potassium chromate" OR "Sodium
chromate" OR "Sodium dichromate dehydrate"
OR "lead chromate" OR "zinc chromate" OR
"strontium chromate" OR "ammonium
dichromate" OR "ammonium chromate" OR
13765-19-0 OR 1333-82-0 OR 7789-00-6 OR
7778-50-9 OR 7775-11-3 OR 7789-12-0 OR
13530-65-9 OR 7738-94-5 OR 18540-29-9 OR
7758-97-6 OR 11119-70-3 OR 11103-86-9 OR
13530-65-9 OR 7788-98-9 OR 77898-09-5 OR
7789-06-2)
Refined by: Research Areas = Toxicology,
Biochemistry molecular biology, Public
environmental occupational health,
Dermatology, Cell biology, Oncology, Life
sciences biomedicine other topics, Allergy,
Veterinary sciences, Developmental
biology, Immunology, Reproductive
biology, Pathology, Physiology, Urology
nephrology, Hematology, Neurosciences
neurology, Respiratory system,
Cardiovascular system cardiology,
Obstetrics gynecology, Infections diseases,
Gastroenterology hepatology, Microscopy
Web of Science
(1/29/2013)
(7/19/2013)
(2/5/2014)
Topic = (hexavalent chromium OR (hexavalent
AND chromium) Chromium VI OR CrVI OR Cr VI
OR "Chromic acid" OR "Calcium chromate" OR
"Chromic trioxide" OR "Potassium dichromate"
OR "Potassium chromate" OR "Sodium
chromate" OR "Sodium dichromate dehydrate"
OR "lead chromate" OR "zinc chromate" OR
"strontium chromate" OR "ammonium
dichromate" OR "ammonium chromate" OR
13765-19-0 OR 1333-82-0 OR 7789-00-6 OR
7778-50-9 OR 7775-11-3 OR 7789-12-0 OR
13530-65-9 OR 7738-94-5 OR 18540-29-9 OR
7758-97-6 OR 11119-70-3 OR 11103-86-9 OR
13530-65-9 OR 7788-98-9 OR 77898-09-5 OR
7789-06-2)
AND
cancer* OR carcinogen* OR chronic OR
Refined by: Research Areas = Chemistry,
Environmental sciences ecology,
Spectroscopy, Pharmacology pharmacy,
Water resources, Genetics heredity,
Science technology other topics,
Biophysics, Food sciences technology,
Endocrinology metabolism, Research
experimental medicine, Nutrition
dietetics, Zoology, General internal
medicine, Construction building
technology, Parasitology, Medical
laboratory technology, Education
educational research,
Otorhinolaryngology, Rheumatology,
Anatomy morphology, Emergency
medicine, Mycology, Sport sciences,
Psychiatry
This document is a draft for review purposes only and does not constitute Agency policy,
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Database
(Search Date)
Keywords
Limits
subchronic OR genotox* OR inhalation
absorption OR oral absorption OR mice OR
mouse OR Mutagenicity OR pharmacokinetic
OR rat OR rats OR (toxic* NOT (fish OR
bacteria* OR microorganism* OR plant*) OR
tumor*
Toxline (includes
TSCATS)
(1/29/2013)
(7/19/2013)
(2/5/2014)
18540-29-9 OR 7789-09-5 OR 13765-19-0 OR
1333-82-0 OR 7758-97-6 OR 7789-00-6 OR
7778-50-9 OR 7775-11-3 OR 7789-12-0 OR
7789-06-2 OR 13530-65-9 OR 7788-98-9 OR
7738-94-5 OR 13530-68-2
Not PubMed; synonyms included
TSCATS2
(1/29/2013)
(7/19/2013)
(2/5/2014)
18540-29-9
None
1
2
3
4
5
a For Web of Science, results were obtained by searching the research areas noted in the "Limits" column using the
italicized terms in the "Keywords" column (starting with 'Topic = (hexavalent chromium...)"), and subsequent
filtering in EndNote using the additional keywords in normal text (starting with "cancer* OR ...").
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Table 2-2. Summary of additional search strategies for hexavalent chromium
Approach used
Manual search
of citations
from reviews
conducted by
other
international
and federal
agencies
Source(s)
ATSDR (2012). Toxicological profile
for chromium. Atlanta, GA: US
Department of Health and Human
Services, Public Health Service.
U.S. EPA (2010). Toxicological
review of hexavalent chromium
(external review draft).
(EPA/635/R-10/004A).
Washington, DC.
Date
performed
1/2013
1/2013
Number of additional citations
identified
40
59
2
3
4 2.2. Selection of Critical Studies in Early Stages of Draft Development
5 2.2.1. General Approach
6 In response to the NRC recommendations, each study retained after the literature search
7 and screen is evaluated for aspects of its design or conduct that could affect the interpretation of
8 results and the overall contribution to the synthesis of evidence for determination of hazard
9 potential. Much of the key information for conducting this evaluation can generally be found in the
10 study's methods section and in how the study results are reported. Importantly, the evaluation at
11 this stage does not consider study results, or more specifically, the direction or magnitude of any
12 reported effects. For example, standard issues for evaluation of experimental animal data identified
13 by the NRC and adopted in this approach include consideration of the species and sex of animals
14 studied, dosing information (dose spacing, dose duration, and route of exposure), endpoints
15 considered, and the relevance of the endpoints to the human endpoints of concern.
16 To facilitate the evaluation outlined above, evidence tables are constructed that
17 systematically summarize the important information from each study in a standardized tabular
18 format as recommended by the NRC [2011]. In general, the evidence tables may include all studies
19 that inform the overall synthesis of evidence for hazard potential. At this early stage of study
20 evaluation the goal is to be inclusive. Exclusion of studies may unnecessarily narrow subsequent
21 analyses by eliminating information that might later prove useful. Premature exclusion might also
22 give a false sense of the consistency of results across the database of studies by unknowingly
23 reducing the diversity of study results. However, there may be situations in which the initial review
24 of the available data will lead to a decision to focus on a particular set of health effects and to
25 exclude others from further evaluation. This situation could occur, for example, with a chemical
26 with a large database that has a few well-developed areas of research, but many other areas that
27 consist of sparse data, offering a very limited basis for drawing conclusions regarding hazard. In
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 this case, EPA will focus on the more developed areas of research for hazard identification. For
2 hexavalent chromium, the identification of the health effects to be focused on was discussed in
3 Problem Formulation, and the results of any exclusions are described below in Section 2.2.2.
4 Additionally, a study can be excluded at this stage if flaws in its design, conduct, or reporting
5 are so great that the results would not be considered credible. Such study design flaws are
6 discussed in a number of EPA's guidelines (see http://www.epa.gov/iris/backgrd.html) or
7 summarized in the draft Preamble to the IRIS Toxicological Review ("Preamble")4. Examples of
8 these flaws include studies where impurities in the test chemical are so great as to prohibit
9 attribution of the results to the chemical, or studies where concurrent or essential historical control
10 information is lacking. Studies with fundamental flaws in their design, conduct, or reporting are not
11 included in evidence tables. Such exclusions in the case of experimental animal studies of
12 hexavalent chromium are also described below in the Section 2.2.2.
13 The size of the database can influence both the type and number of evaluation criteria that
14 are applied at this early stage. For example, if there are few studies on a health effect, additional
15 evaluation criteria might not be needed, and thus the evidence tables may include all studies
16 without severe flaws. Especially with smaller databases, it is important to consider all studies and
17 not exclude studies unnecessarily. On the other hand, for larger databases, such as that for
18 hexavalent chromium, additional criteria could facilitate a more efficient review of the database and
19 help to focus on the more informative studies indicating the potential for hazard. These criteria
20 could be specific to each type of study or a particular endpoint, and may consider factors such as
21 those discussed in EPA's guidelines or summarized in the draft Preamble. Application of such
22 additional criteria could result in initially setting aside some studies and not summarizing them in
23 the evidence tables, although they would still be evaluated as possible sources of supporting health
24 effects information during assessment development. Application of such criteria in the case of
25 experimental animal studies of hexavalent chromium are also described below in Section 2.2.2.
26 2.2.2. Selection of Critical Experimental Animal Studies for Evidence Tables for Hexavalent
27 Chromium
28 After the literature search was manually screened for pertinence (Figure 2-1; Sources of
29 Chronic Health Effects Data), sixty experimental animal studies were identified as sources of health
30 effects data and considered for data extraction to evidence tables and exposure-response arrays.
31 From these studies, exclusions were first made if they exclusively examined health effects not
32 identified in Problem Formulation. Next, studies were excluded if any fundamental flaws were
33 identified in their design or conduct The remaining studies are all sources of health effects data
34 that may be used in the assessment. However, additional criteria were then applied to focus the
4 See the draft Preamble in the Toxicological Review of Ammonia (revised external review draft) at
http://cfpub.epa.gov/ncea/iris drafts/recordisplay.cfm?deid=254524 or the Toxicological Review of
Trimethylbenzenes (revised external review draft) at
http://cfpub.epa.gov/ncea/iris drafts/recordisplay.cfrn?deid=254525.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 evidence tables on the more methodologically robust studies. The studies summarized in evidence
2 tables are considered the "critical" studies from which the study methods and results are presented
3 in preliminary evidence tables and exposure-response arrays.
4 Exclusions based on results of problem formulation
5 As discussed in the Problem Formulation for hexavalent chromium, the hazard
6 identification in the IRIS assessment will focus on the following health effects: respiratory,
7 gastrointestinal, liver, immunological, hematological, reproductive, developmental, and cancer.
8 These represent the health effects for hexavalent chromium with well-developed areas of research.
9 A screen of the literature published after publication of the ATSDR [2012] Toxicological Profile and
10 other recent reviews did not identify other health effect categories that should be added to those
11 already identified. Focus on these health effects resulted in the exclusion of one study, Vyskocil et
12 al. [1993], from the evidence tables because the study presented an evaluation of kidney endpoints
13 only.
14 Exclusions due to fundamental flaws in their design or conduct
15 All experimental animal studies that were sources of chronic health effects data were
16 evaluated for potential flaws in their design, reporting, or conduct. As a result, nine studies were
17 removed from further consideration in the assessment. The specific studies and basis for exclusion
18 are summarized in Table 2-3.
19
20
21
Table 2-3. Animal studies with fundamental flaws not considered further in
the assessment
Rationale for exclusion
Issues with animal husbandry.
Non-reproducible animal populations used.
Compromised by data record-keeping
anomalies.
References and specific issue(s) identified
Borneffetal. (1968)
The animal colony was compromised by mousepox infection,
and widespread cannibalism occurred in all dose groups.
Anwar etal. (1961)
Dogs of multiple breeds from an unspecified source.
Aruldhas et al. (2006); Aruldhas et al. (2005); Aruldhas et al. (2004);
Subramanian et al. (2006)
Monkeys captured by local government for creating a public
nuisance.
Junaid et al. (1996a); Kanoiia et al. (1996); Samuel et al. (2011)
See discussion in text.
22
23 EPA determined that two of the studies listed in Table 2-3 contained datasets thatwere
24 essentially identical, despite being published as separate studies of potassium dichromate in
25 different rodent species. The studies are:
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 • Kanojia, RK; Junaid, M; Murthy, RC. [1996]. Chromium induced teratogenicity in female
2 rat. Toxicology letters 89: 207-213.
3 • Junaid, M; Murthy, RC; Saxena, DK. [1996a]. Embryo- and fetotoxicity of chromium in
4 pregestationally exposed mice. Bulletin of environmental contamination and toxicology
5 57:327-334.
6 Incidence data for rats in Table 2 from Kanojia et al. [1996] and for mice in Table 2 from Tunaid et
7 al. [1996a] are identical for all entries (with the exception of the exposure group categories]. In
8 addition, chromium tissue concentration data for rats in Table 3 from Kanojia et al. [1996] and for
9 mice in Table 3 from Tunaid et al. [1996a] have identical means and standard deviations for all but
10 one entry. Otherwise, the only differences between these tables from the two studies are the
11 exposure group categories and the number of significant figures. EPA considered the similarity in
12 the two data sets from two separate experiments in different species to be highly improbable.
13 Related studies by the same investigators published after the two studies at issue do not contain an
14 erratum for the data [Tunaid etal. [1996b]: Murthy etal. [1996]: Kanojia etal. [1998]]. Requests
15 were sent to the corresponding authors seeking clarification of the study findings, but no additional
16 information has been received. Additionally, a search for any correspondence regarding data
17 correction did not identify any relevant information. Finally, the journal editors were contacted,
18 but no errata or retractions have yet been issued. Until questions regarding these studies are
19 resolved, data from Kanojia et al. [1996] and Tunaid etal. [1996a] will be excluded from further
20 consideration.
21 In addition, an internal review found that data from Samuel etal. [2011] were identical to
22 data reported in Banuetal. [2008] despite being identified as separate and independent studies.
23 Hormone data from Table 3 of Samuel et al. [2011] appears to have been copied directly from Table
24 2 of Banuetal. [2008]. calling into question whether the exposure and control groups were
25 performed concurrently in the experiments described in Samuel etal. [2011]. Data from Banu et al.
26 [2008] currently remain in the tables.
27 Additional criteria applied to identify more methodologically robust studies
28 The remaining fifty references include studies designed to examine repeat-dose oral and
29 inhalation toxicity and specialized studies of reproductive and developmental toxicity and
30 immunotoxicity, representing a relatively large database of experimental animal literature. Given
31 the size of the database, additional criteria were applied to focus on the more methodologically
3 2 robust studies of hexavalent chromium hazard.
33 An initial screen was conducted to identify studies with limitations in study design, conduct,
34 or reporting that would reduce the informative ness of the study. Specific issues were identified, as
35 described in Table 2-4. All experimental animal studies that were categorized as sources of chronic
36 health effects data were evaluated with respect to these methodological issues; these issues were
37 not identified in any of the studies that were ultimately included in the evidence tables. Twelve
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1
2
3
4
5
6
7
8
9
10
11
studies were identified as being less informative for characterizing the health effects of hexavalent
chromium because of study design and reporting issues, and were not included in the evidence
tables. The specific studies and basis for exclusion are summarized in Table 2-4. While not
included in evidence tables, these studies will nevertheless be evaluated as possible sources of
supporting health effects information during assessment development.
The remaining thirty-eight studies are considered the critical experimental animal studies
for hazard identification. Data from these studies have been extracted and presented in evidence
tables (Section 3). One of these studies, Stout etal. [2009], contains analyses of data presented
originally in NTP [2008], so these have been listed in the tables together.
Table 2-4. Animal studies considered less informative, not included in
evidence tables but retained as potential supporting information
Rationale for exclusion
Measurements of water consumption and/or body weight were not
provided for animals exposed via drinking water (ad libitum) at high
chromium concentrations (>30 mg hexavalent chromium/L) known to
impact palatability of the drinking water and reduce water
consumption (NTP, 2008, 2007). Reported water consumption and
body weight data are needed to estimate dose.
Incomplete reporting of study results and lack of water consumption
measurements following drinking water exposures.
Test animals were exposed to mixtures including or containing
hexavalent chromium in the absence of a hexavalent chromium-only
exposure group.
Dose could not be estimated with confidence because of ambiguous
reporting in study methods.
Full study could not be obtained.
References
Asmatullah and Noreen (1999); Al-
Hamood et al. (1998); Bataineh et al.
(1997); Elbetieha and AI-Hamood (1997);
Trivedi etal. (1989)
Schroederand Mitchener
(1971);MacKenzie et al. (1958)
Zeidler-Erdely et al. (2013); Davidson et al.
(2004)
Zabulyte et al. (2009); Zabulyte et al.
(2006)
Behari etal. (1978)
12
13
14
15
16
17
18
19
20
21
22
23
2.2.3. Preliminary Evidence Tables and Exposure-Response Arrays
The evidence tables present data from studies related to a specific outcome or endpoint of
toxicity. At a minimum, the evidence tables include the relevant information for comparing key
study characteristics such as study design, exposure metrics, and dose-response information.
Evidence tables will serve as an additional method for presenting and evaluating the suitability of
the data to inform hazard identification for hexavalent chromium during the analysis of hazard
potential and utility of the data for dose-response evaluation. The information in the preliminary
evidence tables is also displayed graphically in preliminary exposure-response arrays. In these
arrays, a significant effect (indicated by a filled circle] is based on statistical significance. The
complete list of references considered in preparation of these materials can be found on the HERO
website athttp://hero.epa.gov/index.cfm?action=landing.main&proiect id=2233.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 2.2.4. Study Characteristics That Will Be Considered in the Evaluation and Synthesis of the
2 Critical Studies for Hexavalent Chromium
3 Beyond the initial methodological screening described above in Sections 2.2.1 and 2.2.2,
4 methodological aspects of a study's design, conduct, and reporting will be considered again in the
5 overall evaluation and synthesis of the pertinent data that will be developed for each health effect.
6 Some general questions that will be considered in evaluating experimental animal studies are
7 presented in Table 2-5. These questions are, for the most part, broadly applicable to all
8 experimental studies.
9
10
Table 2-5. Questions and relevant experimental information for evaluation of
experimental animal studies
Methodological
feature
Question(s) considered
Examples of relevant
information extracted
Test animal
Based on the endpoint(s) in question, are
concerns raised regarding the suitability of
the species, strain, or sex of the test
animals on study?
Test animal species, strain, sex
Experimental setup
Are the timing, frequency and duration of
exposure, as well as animal age and
experimental group allocation procedures/
group size for each endpoint evaluation,
appropriate for the assessed endpoint(s)?
Age/lifestage of test animals at exposure
and all endpoint testing timepoints
Timing and periodicity of exposure and
endpoint evaluations; duration of exposure
Experimental group allocation procedures
and sample size for each experimental
group (e.g., animals; litters; dams) at each
endpoint evaluation
Exposure
Are the exposure conditions and controls
informative and reliable for the endpoint(s)
in question, and are they sufficiently
specific to the compound of interest?
Test article composition, stability, and
vehicle control
Exposure administration techniques (e.g.,
route; chamber type) and related controls
Endpoint evaluation
procedures
Do the procedures used to evaluate the
endpoint(s) in question conform to
established protocols, or are they
biologically sound? Are they sensitive for
examination of the outcome(s) of interest?
Specific methods for assessing the effect(s)
of exposure, including related details (e.g.,
biological matrix or specific region of
tissue/organ evaluated)
Endpoint evaluation controls, including
those put in place to minimize evaluator
bias
Outcomes and data
reporting
Were data reported for all pre-specified
endpoint(s) and study groups, or were any
data excluded from presentation/
analyses?
Data presentation for endpoint(s) of
interest
Note: "Outcome" refers to findings from an evaluation (e.g., steatosis), whereas "endpoint" refers to the
evaluation itself (e.g., liver histopathology).
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1
2 Evaluation of some specific methodological features identified in Table 2-5, such as
3 exposure, is likely to be relatively independent of outcome. Other methodological features, in
4 particular those related to experimental setup and endpoint evaluation procedures, are generally
5 outcome specific (e.g., reproductive and developmental toxicity). In general, experimental animal
6 studies will be compared against traditional assay formats (e.g., those used in guideline studies),
7 with deviations from the protocol evaluated in light of how the deviations could alter interpretation
8 of the outcome in question. A full evaluation of all critical studies will be performed as part of the
9 critical review and synthesis of evidence for hazard identification for each of the health endpoints
10 identified in the evidence tables presented in Section 3.
11
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1
2 3. PRELIMINARY EVIDENCE TABLES AND
3 EXPOSURE-RESPONSE ARRAYS
4 3.1. Data Extraction for Animal Studies: Preparation of Preliminary
5 Evidence Tables and Exposure-Response Arrays
6 For each critical study selected, key information on the study design, including
7 characteristics that inform study quality, and study results pertinent to evaluating the health effects
8 from chronic oral and inhalation exposure to hexavalent chromium are summarized in preliminary
9 evidence tables. Most results are presented as the percent change from the control group; an
10 asterisk (*) indicates a result that has been calculated and reported by study authors to be
11 statistically significant compared to controls (p<0.05).
12 The information in the preliminary evidence tables is also displayed graphically in
13 preliminary exposure-response arrays. In these arrays, a significant effect (indicated by a filled
14 circle) is based on statistical significance. The complete list of references considered in preparation
15 of these materials can be found on the HERO website at
16 http://hero.epa.gov/index.cfm?action=landing.main&project id=2233.
17
18
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.2. Respiratory System Effects
2
3
Table 3-1. Evidence pertaining to respiratory system effects following
inhalation exposure to hexavalent chromium
Reference and study design
Results
Lung Weight
Glaseretal. (1990)
Wistar Rat, Male (10/group)
0, 0.050, 0.10, 0.20, 0.40 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
30 d, 90 d, or 90 d with 30 d recovery
Generation method (cyclone nebulizer),
analytical concentration, and MMD reported;
analytical method not reported.
Percent change from control by exposure group for relative lung weight:
30 d
16.3*
25.6*
27.9*
41.9*
90 d
9.1
13.6*
25.0*
47.7*
90 d with 30 d recovery
4.7
11.6*
23.3*
23.3*
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.025, 0.050, 0.1 mg Cr Vl/m3 as sodium
dichromate (Na2Cr2O7); 0, 0.063 mg Cr Vl/m3 as
pyrolized mixture of 3:2 Cr Vl/Cr III oxide
(Cr5O12) (dynamic whole-body chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and cyclone),
analytical method (photometric, by
diphenylcarbazine complexation), analytical
concentration, and MMD reported.
Percent change from control by exposure group:
Group Relative weight
Control (0 mg/m3)
Cr5O12(0.1mg/m3) 26.1*
Na2Cr2O7 (0.025 mg/m3) No data provided
Na2Cr2O7 (0.050 mg/m3) No data provided
Na2Cr2O7 (0.1 mg/m3) 15.2
Organ weights for lung at low and mid Na2Cr2O7 exposure groups were
measured but results not reported by authors due to lack of statistical
significance.
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
28 d
Generation method (jet nebulizer and cyclone),
analytical method (atomic absorption
spectrometry; gravimetric filter), analytical
concentration, and MMD reported.
Related reference: Glaseretal. (1988)
Authors state that lung weights were statistically significantly increased
above 0.025 mg/m3 Cr VI but data were not provided.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and cyclone),
analytical method (atomic absorption
spectrometry; gravimetric filter), analytical
concentration, and MMD reported.
Related reference: Glaser et al. (1988)
Johansson et al. (1986a)
Rabbit, Male (8/group)
0, 0.9 mg Cr Vl/m3 as Na2CrO4 aerosol exposure
(dynamic whole-body chamber)
6 hr/d, 5 d/wk
4-6 wk
Generation method (ultrasonic nebulizer),
analytical method (gravimetric filter collection;
atomic absorption spectrometry and modified
diphenylcarbazine method), analytical
concentration, and MMAD reported.
Results
Percent change from control by exposure group:
mg/m3 Relative weight
0
0.025 -2.9
0.050 8.8*
0.100 11.8*
0.200 35.3*
No statistically significant changes in the weight of the lower left lobe
(2.4 ± 0.2 g in controls and 2.2 ± 0.2 g in treated) were reported.
Histopathology
Glaseretal. (1990)
Wistar Rat, Male (10/group)
0, 0.050, 0.10, 0.20, 0.40 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
30 d
Generation method (cyclone nebulizer),
analytical concentration, and MMD reported;
analytical method not reported.
Glaseretal. (1990)
Wistar Rat, Male (10/group)
0, 0.050, 0.10, 0.20, 0.40 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
90 d
Generation method (cyclone nebulizer),
analytical concentration, and MMD reported;
analytical method not reported.
Incidence (percent) by exposure group:
Bronchioalveolar
mg/m3 hyperplasia Histiocytosis
0 1/10 (10) 1/10 (10)
0.05 7/10 (70) 5/10 (50)
0.10 10/10(100) 8/10(80)
0.20 9/10 (90) 5/10 (50)
0.40 9/10 (90) 3/10 (30)
Statistical significance was not assessed by study
Incidence (percent) by exposure group:
Bronchioalveolar
mg/m3 Hyperplasia Histiocytosis
0 0/10 (0) 2/10 (20)
0.05 3/10 (30) 9/10 (90)
0.10 2/10(20) 10/10(100)
0.20 3/10 (30) 9/10 (90)
0.40 7/10 (70) 10/10 (100)
Statistical significance was not assessed by study
Fibrosis
0/10 (0)
0/10 (0)
4/10 (40)
1/10 (10)
3/10 (30)
authors.
Fibrosis
0/10 (0)
1/10 (10)
0/10 (0)
0/10 (0)
0/10 (0)
authors.
This document is a draft for review purposes only and does not constitute Agency policy,
3-3 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Glaseretal. (1990)
Wistar Rat, Male (10/group)
0, 0.050, 0.10, 0.20, 0.40 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
90 d exposure with 30 d recovery
Generation method (cyclone nebulizer),
analytical concentration, and MMD reported;
analytical method not reported.
Incidence (percent) by exposure group:
Bronchioalveolar
Histiocytosis
hyperplasia
0/10 (0)
1/10 (10)
0/10 (0)
7/10 (70)
3/10 (30)
1/10 (10)
6/10 (60)
5/10 (50)
8/10 (50)
10/10 (100)
Fibrosis
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (0)
Statistical significance was not assessed by study authors.
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and cyclone),
analytical method (atomic absorption
spectrometry; gravimetric filter), analytical
concentration, and MMD reported.
Related reference: Glaseretal. (1988)
No treatment-related changes in lung histopathology.
Johansson etal. (1986a)
Rabbit, Male (8/group)
0, 0.9 mg Cr Vl/m3 as Na2CrO4 aerosol exposure
(dynamic whole-body chamber)
6 hr/d, 5 d/wk
4-6 wk
Generation method (ultrasonic nebulizer),
analytical method (gravimetric filter collection;
atomic absorption spectrometry and modified
diphenylcarbazine method), analytical
concentration, and MMAD reported.
Qualitative histopathology results indicate that no increases in
phospholipid accumulation or interstitial inflammation in lung tissue
were observed. In Type II cells, no nodular proliferation, increased
volume density, size, or number were observed. However, nodular
accumulation of alveolar macrophages was observed in three of eight
exposed rabbits.
Other Respiratory Histopathology
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.025, 0.05, 0.1 mg Cr Vl/m3 as sodium
dichromate (Na2Cr2O7); 0, 0.063 mg Cr Vl/m3 as
pyrolized mixture of 3:2 Cr Vl/Cr III oxide
(Cr5O12) (dynamic whole-body chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and cyclone),
analytical method (photometric, by
diphenylcarbazine complexation), analytical
concentration, and MMD reported.
There were weak accumulations of pigment-loaded macrophages in
alveolar region of 8 rat lungs in the lowest Na2Cr2O7 exposure group
(0.025 mg/m3) and moderate accumulations in the alveolar and
peribronchial regions of all evaluated rats of the other chromium
exposed groups, compared to no accumulation in the controls.
Accumulations of eosinophilic substance inside the alveolar lumens
were seen in 3 out of 18 rats in the Cr5O12-exposed group (0.063 mg
Cr Vl/m3). Focal thickened septa in the lungs of 3 rats, combined with
interstitial fibrosis in 2 cases, were also observed in the Cr5O12-exposed
group. Focal bronchioalveolar hyperplasia was observed in one rat from
each group (unclear whether this includes control or just dosed groups).
No hyperplastic changes or tumors were observed in the nasal cavities
of the rats.
This document is a draft for review purposes only and does not constitute Agency policy,
3-4 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Lung: BAL Fluid
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050 mg Cr Vl/m3 as Na2Cr2O7 aerosol
exposure (dynamic whole-body chamber)
22 hr/d, 7 d/wk
28 d
Generation method (jet nebulizer and cyclone),
analytical method (atomic absorption
spectrometry; gravimetric filter), analytical
concentration, and MMD reported.
Related reference: Glaseretal. (1988)
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.200 mg Cr Vl/m3 as Na2Cr2O7
aerosol exposure (dynamic whole-body
chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and cyclone),
analytical method (atomic absorption
spectrometry; gravimetric filter), analytical
concentration, and MMD reported.
Related reference: Glaseretal. (1988)
Percent change from control by
mg/m
0
0.025
0.050
mg/m
0
0.025
0.050
Percent chanj
mg/m3
0
0.025
0.050
0.200
mg/m3
0
0.025
0.050
0.200
Macrophages
9.4
3.1
Macrophage
diameter
-0.9
6.1
;e from control by
Macrophages
-6.3
-15.6*
-37.5*
Macrophage
diameter
..
9.0*
21.3*
27.9*
exposure group:
Polynuclear
macrophages
57.1*
28.6
Lymphocytes
100.0*
185.7*
exposure group:
Polynuclear
macrophages
70.0
170.0*
180.0*
Lymphocytes
..
36.4*
118.2*
27.3
Macrophages in
telophase
90.9*
118.2*
Granulocytes
14.3
42.9*
Macrophages in
telophase
142.9*
335.7*
114.3*
Granulocytes
..
36.4
145.5*
-54.5*
This document is a draft for review purposes only and does not constitute Agency policy,
3-5 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Glaseretal. (1990)
Wistar Rat, Male (10/group)
0, 0.050, 0.10, 0.20, 0.40 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
30 d
Generation method (cyclone nebulizer),
analytical concentration, and MMD reported;
analytical method not reported.
Glaseretal. (1990)
Wistar Rat, Male (10/group)
0, 0.050, 0.10, 0.20, 0.40 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
90 d
Generation method (cyclone nebulizer),
analytical concentration, and MMD reported;
analytical method not reported.
Results
Percent chanj
mg/m
0
0.05
0.10
0.20
0.40
mg/m
0
0.05
0.10
0.20
0.40
Percent chang
mg/m3
0
0.05
0.10
0.20
0.40
mg/m3
0
0.05
0.10
0.20
0.40
;e from control by
Total Protein
43.1*
79.2*
116.7*
181.0*
Total
macrophages
-
0.0
7.7
53.8*
76.9*
;e from control by
Total protein
75.2*
44.2*
211.1*
331.4*
Total
macrophages
-
-25.0*
-18.8
43.7*
106.2*
exposure group:
Albumin
82.9*
118.3*
184.1*
229.3*
Dividing
macrophages
-
58.3
116.7*
125.0*
66.7
exposure group:
Albumin
49.4*
11.7
51.9*
139.0*
Dividing
macrophages
-
216.7*
333.3*
283.3*
233.3*
Lactate
dehydrogenase
14.3
25.0*
75.0*
125.0*
Cell viability
-
1.1
1.1
3.4
4.5*
Lactate
dehydrogenase
17.2*
6.9
117.2*
186.2*
Cell viability
-
2.2
4.5
4.5
3.4
This document is a draft for review purposes only and does not constitute Agency policy,
3-6 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Glaseretal. (1990)
Wistar Rat, Male (10/group)
0, 0.050, 0.10, 0.20, 0.40 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
90 d exposure with 30 d recovery
Generation method (cyclone nebulizer),
analytical concentration, and MMD reported;
analytical method not reported.
Cohen etal. (2003)
F344 Rat, Male (30/group)
0, 0.36 mg Cr Vl/m3 as calcium chromate
(dynamic nose-only chamber)
5 hr/d, 5 d/wk
Up to 48 wk
Generation method (nebulization of aqueous
CaCrO4 suspension), analytical method
(gravimetic filter), analytical concentration, and
MMAD reported.
Results
Percent chanj
mg/m
0
0.05
0.10
0.20
0.40
mg/m
0
0.05
0.10
0.20
0.40
*e from control by
Total protein
46.7*
28.2*
31.3*
53.3*
Total
macrophages
-
0.0
-7.1
0.0
7.1
Percent change from control by
cells (xlO6) in
mg/m3
4 wk:
0
0.36
8 wk:
0
0.36
12 wk:
0
0.36
24 wk:
0
0.36
48 wk:
0
0.36
lavage:
Neutrophils
—
767*
__
8000*
—
3800*
—
1747*
—
4100*
exposure group:
Albumin
-14.1
-10.9
51.7*
67.2*
Dividing
macrophages
-
9.1
36.4
54.5
-9.1
exposure group in
Macrophages
—
-17.7
__
-45.7*
—
-13.6*
—
-51.3*
—
-30.9*
Lactate
dehydrogenase
-14.8
0.0
14.8
7.4
Cell viability
-
1.1
0.0
-1.1
0.0
pulmonary immune
Total cells
—
-18.5
__
-35.7*
—
2.1
—
17.7*
—
55.3*
This document is a draft for review purposes only and does not constitute Agency policy,
3-7 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Johansson et al. (1986b)
Rabbit, Male (8/group)
0, 0.9 mg Cr Vl/m3 as Na2CrO4 aerosol exposure
(dynamic whole-body chamber)
6 hr/d, 5 d/wk
4-6 wk
Generation method (ultrasonic nebulizer),
analytical method (atomic absorption
spectrometry and diphenylcarbazine method),
analytical concentration, and MMAD reported.
Results
Percent change from control by exposure group:
Number of Macrophage cell Variance of
mg/m3 macrophage cells (xlO6) diameter (u.m) diameter (u.m2)
o
0.9 75 4.4 -7.4
Qualitative results from light microscopic findings indicate no increase in
variance of cell diameter or increase in number of cells other than
macrophages in lavage fluid. However, there was an increased number
of alveolar macrophages (not reported to be statistically significant).
Qualitative results from electron microscopic findings indicate no
increased protrusions from cell surface or surface blebs, but increased
intracellular laminated structures and large lysosomes (not reported to
be statistically significant).
Other/Gross Findings
Kim et al. (2004)
Sprague-Dawley Rat, Male (5/group)
0, 0.2, 0.5, 1.25 mg/m3 as CrO3 (dynamic whole-
body chamber)
5 hr/d, 5 d/wk,
90 d
Generation method (mist generator), analytical
method (gravimetric filter, flame atomic
absorption spectrophotometry), and analytical
concentration reported; MMAD not reported.
Authors report the following, but do not provide data:
CrO3-treated groups showed decreased activity, peculiar sound during
respiration starting at Week 1 and disappeared by Week 8. Alopecic
effect seen in some animals from high dose group; 2/5 animals in high
dose group experienced nasal hemorrhage from Day 10 through Week
4.
No abnormal gross pathological findings in any group with exception of
nasal hemorrhage from Day 10 through 4 weeks for 2 animals in 1.25-
mg/m3 group (animals recovered at Week 4 and were normal for
remainder of study period).
*Significantly different from control (p<0.05) as calculated by study authors.
Percent change from control calculated as (Treated - Control) 4- Control x 100.
This document is a draft for review purposes only and does not constitute Agency policy,
3-8 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
•20.1
E
g
8
0.01
• Statistically Significant
O O
•
• • • O 4
00 0
4
CO O O O O f5 ^
*-; m m m £5 **"* 2
1 | 1 I 1 5 1
_:_:_: 75 S 5 T5
3 oi tl « -jj £ c
8 8 8 1 5 s 1
13 13 13 ^ Si Jl
JS o
O
total macrophages
I
4
I
00 O g
S 2 —
i/l l/l 00
00 00 G1
cn OS »-t
:• T5
111
0
"""
diameter
4
1 C
»
> l
00 O
ro ro
IT) U"i
CO CO
Cl CT1
™ "ro
1 S
poly-
nuclear
Macrophages
«
t i
O Not Statistically Significant
> • (1 <)
|
1 1
1 1
m 1/1
CO CO
Cn CM
i
i i
?
5
trt 1/1
ro ra
^J (J
telo-
phase
s s s
m CTi ro
s s a
§ § 2
Ci cH ~~"
' ' S
3i S £
fTJ 10 w
e?
dividing
4
'ro
§
rsi
re
ro ra
lympho-
cytes
4
) C
t
3
1 g
2 2
W1 l/l
r
i
-
i
Si Si
ra ro
granulo-
cytes
Other Cells
ii ii • ii ii o o o o
o S |
2 2 o^
§ S 2
m 01 —
? w 1
S M H
2 E S
a i I
r r a
o» at — i \
Si Si flj
n
13
cell
viability
Other effects
2
3
4
Figure 3-1. Exposure-response array of respiratory system effects (BAL fluid) following inhalation exposure to
hexavalent chromium.
This document is a draft for review purposes only and does not constitute Agency policy,
3-9
DRAFT— DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1
2
3
l q
"E
1
§
i
I0-1;
o
u
.
0.01 -
• Statistically Significant O Not Statistically Significant
T T T
1 > 41 II • II
• o o o o i>
0 • 0
*O "D ^ * "D "O
O Q O ra CO Q
m ol cO ^ rM ffi
S*rf Q tO *•> 'W"
cn oo
1 1 I 2 i i
"ro "ra rH "ro "ro
S*- « BE 4? **
a; — : S
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.3. Gastrointestinal Effects
2
3
Table 3-2. Evidence pertaining to gastrointestinal (GI) effects following oral
exposure to hexavalent chromium
Reference and study design
Results
Small Intestine, Duodenum: Histopathology
NTP (2008)
F344 Rat (50/sex/group)
Water: 0, 14.3, 57.3, 172, 516 ppm
sodium dichromate dihydrate; equivalent
to 0, 0.21, 0.77, 2.1, 5.9 mg Cr Vl/kg-d (M)
0, 0.24, 0.94, 2.4, 7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
NTP (2007)
F344 Rat (10/sex/group)
Water: 0, 62.5, 125, 250, 500, 1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 1.7, 3.5, 5.9, 11.2, 20.9 mg Cr Vl/kg-d
(M/F)
7 d/wk, 3 mo
Thompson et al. (2012)
F344 Rat, Female (15/group)
Water: 0, 0.3, 4, 60, 170, 520 ppm
sodium dichromate dihydrate; equivalent
to 0, 0.017, 0.24, 3.54, 10.04, 30.65 mg Cr
Vl/kg-d
7 d/wk, 91 d
Incidence (percent) by exposure group:
Males
mg Cr Vl/kg-d Histiocytic cellular infiltration
0 0/48 (0)
0.21 0/48 (0)
0.77 6/47 (13)*
2.1 36/46 (78)*
5.9 47/48 (98)*
Females
mg Cr Vl/kg-d Histiocytic cellular infiltration
0 0/46 (0)
0.24 0/49 (0)
0.94 1/48 (2)
2.4 30/46 (65)*
7 47/50 (94)*
Incidence (percent) by exposure group:
Males
mg Cr Vl/kg-d Histiocytic cellular infiltration
0 0/10 (0)
1.7 0/10 (0)
3.5 7/10 (70)*
5.9 9/10 (90)*
11.2 8/10 (80)*
20.9 7/10 (70)*
Females
Histiocytic cellular infiltration
0/10 (0)
1/10 (10)
5/10 (50)*
7/10 (70)*
8/10 (80)*
10/10 (100)*
Incidence (percent) by exposure group:
mg Cr Vl/kg-d Apoptosis Crypt cell hyperplasia Histiocytic infiltration
0 0/10 (0) 0/10 (0)
0.017 0/10 (0) 0/10 (0)
0.24 0/10 (0) 0/10 (0)
3.54 3/10 (30) 0/10 (0)
10.04 4/10(40)* 5/10(50)*
30.65 7/10(70)* 4/10(40)*
0/10 (0)
0/10 (0)
0/10 (0)
9/10(90)*
10/10(100)*
10/10(100)*
This document is a draft for review purposes only and does not constitute Agency policy,
3-11 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
NTP (2008)
B6C3F1 Mouse (50/sex/group)
Water: 0, 14.3, 28.6, 85.7, 257.4 ppm
sodium dichromate dihydrate (M)
0, 14.3, 57.3, 172, 516 ppm sodium
dichromate dihydrate (F); equivalent to
0, 0.38, 0.91, 2.4, 5.9 mg Cr Vl/kg-d (M)
0, 0.38, 1.4, 3.1, 8.7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
NTP (2007)
B6C3F1 Mouse (10/sex/group)
Water: 0, 62.5, 125, 250, 500, 1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 3.1, 5.3, 9.1, 15.7, 27.9 mg Cr Vl/kg-d
(M/F)
7 d/wk, 3 mo
NTP (2007)
B6C3F1, BALB/c, am3-C57BL/6 Mouse,
Male (5-10/group)
Water: 0, 62.5, 125, 250 ppm sodium
dichromate dihydrate; equivalent to
0,2.8, 5.2, 8.7 mgCr Vl/kg-d
7 d/wk, 3 mo
Strain Comparison Study
Results
Incidence (percent) by exposure group:
Males
mg Cr Vl/kg-d
0
0.38
0.91
2.4
5.9
Females
mg Cr Vl/kg-d
0
0.38
1.4
3.1
8.7
Diffuse epithelial hyperplasia
0/50 (0)
11/50 (22)*
18/50 (36)*
42/50 (84)*
32/50 (64)*
Diffuse epithelial hyperplasia
0/50 (0)
16/50 (32)*
35/50 (70)*
31/50 (62)*
42/50 (84)*
Incidence (percent) by exposure group:
Males
mg Cr Vl/kg-d
0
3.1
5.3
9.1
15.7
27.9
Histiocytic
cellular Epithelial
infiltration hyperplasia
0/10 (0) 0/10 (0)
4/10 (40)* 0/10 (0)
5/10 (50)* 8/10 (80)*
10/10 (100)* 10/10 (100)*
10/10 (100)* 10/10 (100)*
10/10 (100)* 10/10 (100)*
Incidence (percent) by exposure group:
B6C3F1
mg Cr Vl/kg-d
0
2.8
5.2
8.7
mg Cr Vl/kg-d
0
2.8
5.2
8.7
Histiocytic
cellular Epithelial
infiltration hyperplasia
0/10 (0) 0/10 (0)
8/10 (80)* 4/10 (40)*
10/10 (100)* 10/10 (100)*
10/10 (100)* 10/10 (100)*
am3-C57BL/6
Histiocytic
cellular Epithelial
infiltration hyperplasia
0/5 (0) 0/5 (0)
2/5 (40)* 5/5 (100)*
5/5 (100)* 5/5 (100)*
4/5 (80)* 5/5 (100)*
Histiocytic cellular infiltration
0/50 (0)
2/50 (4)
4/50 (8)
37/50(74)*
35/50(70)*
Histiocytic cellular infiltration
0/50 (0)
0/50 (0)
4/50 (8)
33/50(66)*
40/50(80)*
Females
Histiocytic
cellular
infiltration
0/10 (0)
7/10 (70)*
8/9 (89)*
10/10 (100)*
10/10 (100)*
10/10 (100)*
BALB/c
Histiocytic
cellular
infiltration
0/10 (0)
4/10 (40)*
8/10 (80)*
10/10 (100)*
Epithelial
hyperplasia
0/10 (0)
0/10 (0)
9/9 (100)*
10/10 (100)*
10/10 (100)*
10/10 (100)*
Epithelial
hyperplasia
0/10 (0)
2/10 (20)
10/10 (100)*
10/10 (100)*
This document is a draft for review purposes only and does not constitute Agency policy,
3-12 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Thompson et al. (2011)
B6C3F1 Mouse, Female (15/group)
Water: 0, 0.3, 4, 14, 60, 170, 520 ppm
sodium dichromate dihydrate; equivalent
to 0, 0.024, 0.32, 1.1, 4.6, 11.6, or
31.1mgCrVI/kg-d
7 d/wk, 91 d
Results
Incidence (percent) by exposure group:
mg Cr Vl/kg-d Villous cytoplasmic vacuolization Villous atrophy Apoptosis
0 0/10 (0)
0.024 0/10 (0)
0.32 0/10 (0)
1.1 0/10(0)
4.6 5/10 (50)*
11.6 10/10(100)*
31.1 7/10(70)*
mg Cr Vl/kg-d Cryptcell hyperplasia
0 0/10 (0)
0.024 0/10 (0)
0.32 0/10 (0)
1.1 0/10(0)
4.6 0/10 (0)
11.6 9/10(90)*
31.1 9/10(90)*
0/10 (0) 0/10 (0)
0/10 (0) 0/10 (0)
0/10 (0) 0/10 (0)
0/10 (0) 0/10 (0)
0/10 (0) 0/10 (0)
1/10(10) 3/10(30)
3/10(30)* 4/10(40)*
Histiocytic infiltration
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (0)
1/10 (10)
10/10 (100)*
10/10 (100)*
Small Intestine, Jejunum: Histopathology
NTP (2008)
B6C3F1 Mouse (50/sex/group)
Water: 0, 14.3, 28.6, 85.7, 257.4 ppm
sodium dichromate dihydrate (M)
0, 14.3, 57.3, 172, 516 ppm sodium
dichromate dihydrate (F); equivalent to
0, 0.38, 0.91, 2.4, 5.9 mg Cr Vl/kg-d (M)
0, 0.38, 1.4, 3.1, 8.7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
Thompson et al. (2012)
F344 Rat, Female (15/group)
Water: 0, 0.3, 4, 60, 170, 520 ppm sodium
dichromate dihydrate; equivalent to 0,
0.017, 0.24, 3.54, 10.04,
30.65 mg Cr Vl/kg-d
7 d/wk, 91 d
Incidence (percent) by exposure group in females:
mgCrVI/kg-d Diffuse epithelial hyperplasia Histiocytic cellular infiltration
0 0/50 (0)
0.38 2/50 (4)
1.4 1/50 (2)
3.1 0/50(0)
8.7 8/50 (16)*
No significant effects observed in males.
Incidence (percent) by exposure group:
mg Cr Vl/kg-d Histiocytic infiltration
0 0/10 (0)
0.017 0/10 (0)
0.24 0/10 (0)
3.54 3/10 (30)
10.04 7/10(70)*
30.65 9/10(90)*
0/50 (0)
0/50 (0)
0/50 (0)
2/50 (4)
8/50 (16)*
This document is a draft for review purposes only and does not constitute Agency policy,
3-13 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Thompson et al. (2011)
B6C3F1 Mouse, Female (15/group)
Water: 0, 0.3, 4, 14, 60, 170, 520 ppm
sodium dichromate dihydrate; equivalent
to 0, 0.024, 0.32, 1.1, 4.6, 11.6, 31.1 mg
Cr Vl/kg-d
7 d/wk, 91 d
Results
Incidence (percent) by exposure group:
mg Cr Vl/kg-d
0
0.024
0.32
1.1
4.6
11.6
31.1
mg Cr Vl/kg-d
0
0.024
0.32
1.1
4.6
11.6
31.1
Villous cytoplasmic
vacuolization
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (0)
4/10 (40)*
8/10(80)*
5/10 (50)*
Crypt cell hyperplasia
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (0)
5/10(50)*
7/10(70)*
Villous atrophy
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (0)
3/10 (30)
4/10(40)*
Histiocytic infiltration
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (0)
0/10 (10)
9/10(90)*
10/10 (100)*
*Significantly different from control (p<0.05) as calculated by study authors.
Percent change from control calculated as (Treated - Control) 4- Control x 100.
This document is a draft for review purposes only and does not constitute Agency policy,
3-14 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
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41
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.4. Liver Effects
2
3
Table 3-3. Evidence pertaining to liver effects following oral or inhalation
exposure to hexavalent chromium
Reference and study design
Results
Liver Weight - Oral
NTP (2007)
F344 Rat (10/sex/group)
Water: 0, 62.5,125, 250, 500,1,000 ppm sodium
dichromate dihydrate; equivalent to 0,1.7, 3.5,
5.9, 11.2, 20.9 mg Cr Vl/kg-d (M/F)
7 d/wk, 3 mo
Percent change from control by exposure group for males:
mg Cr Vl/kg-d
0
1.7
3.5
5.9
11.2
20.9
Absolute liver weight Relative liver weight
-5
5
-3
-16*
-18*
-3
3
-3
-11*
.9*
No statistically significant effects observed in females.
Chopra etal. (1996)
Wistar Rat, Female (5-6/group)
Water: 0, 25 ppm potassium dichromate;
equivalent to 0,1.4 mg Cr Vl/kg-d
7 d/wk, 22 wk
Percent change from control by exposure group:
mg Cr Vl/kg-d Relative liver weight
0
1.4 125*
Geethaetal. (2003)
Sprague-Dawley Rat, Male (number/group not
reported)
Gavage: 0, 30 mg Cr Vl/kg-d given as potassium
dichromate
7 d/wk, 30 d
Percent change from control by exposure group:
mg Cr Vl/kg-d Relative liver weight
0
30 66.7*
Acharyaetal. (2001)
Wistar Rat, Male (5-6/group)
Water: 0, 20 ppm potassium dichromate;
equivalent to 0,1.5 mg Cr Vl/kg-d
7 d/wk, 22 wk
Percent change from control by exposure group:
mg Cr Vl/kg-d Relative liver weight
0
1.5 125*
NTP (2007)
B6C3F1 Mouse (10/sex/group)
Water: 0, 62.5,125, 250, 500,1,000 ppm sodium
dichromate dihydrate; equivalent to 0, 3.1, 5.3,
9.1, 15.7, 27.9 mg Cr Vl/kg-d (M/F)
7 d/wk, 3 mo
Absolute but not relative liver weight was statistically significantly
decreased at the three highest doses in males and the two highest in
females; this was attributed to a significant reduction in body weight.
This document is a draft for review purposes only and does not constitute Agency policy,
3-16 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
NTP (2007)
BALB/c and am3-C57BL/6 Mouse, Male (5-
10/group)
Water: 0, 62.5,125, 250 ppm sodium dichromate
dihydrate; equivalent to
0,2.8, 5.2, 8.7 mgCrVI/kg-d
7 d/wk, 3 mo
Strain Comparison Study
Absolute but not relative liver weight was statistically significantly
increased at the highest dose in both species; this was attributed to a
significant reduction in body weight.
NTP (1997)
BALB/c Mouse (20/sex/group)
Continuous Breeding Protocol: FO animals
exposed for 7 d/wk, 13 wk total, 1 wk prior to and
12 wk during cohabitation. After cohabitation, FO
breeding pairs were separated and continued on
study diets.
Diet: 0,100, 200, 400 ppm potassium dichromate
(equivalent to 0,17.6, 35.3,141.2 ppm Cr VI)
M/F (FO): 0,19.4, 38.6, 85.7 mg potassium
dichromate/kg-d (equivalent to 0, 6.8,13.6, 30.3
mgCrVI/kg-d)
Lactating F (FO): 0, 32.8, 69.0, 143.1 mg potassium
dichromate/kg-d (equivalent to 0, 11.6, 24.4, 50.5
mg Cr Vl/kg-d)
Percent change from control by exposure group:
mg Cr Vl/kg-d
0
6.8
13.6
30.3
FO males:
Absolute liver weight
-5.5
-11
-17*
FO females:
Absolute liver weight
-5.9
-5.9
-12*
There were no statistically significant changes in relative liver weights.
Liver Weight - Inhalation
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-body
chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and cyclone),
analytical method (atomic absorption
spectrometry; gravimetric filter), analytical
concentration, and MMD reported.
Related reference: Glaseretal. (1988)
Authors report no statistically significant changes in liver weights but
do not provide data.
Kim et al. (2004)
Sprague-Dawley Rat, Male (5/group)
0, 0.2, 0.5,1.25 mg/m3 as CrO3 (dynamic whole-
body chamber)
5 hr/d, 5 d/wk
90 d
Generation method (mist generator), analytical
method (gravimetric filter, flame atomic
absorption spectrophotometry), and analytical
concentration reported; MMAD not reported.
There were no statistically significant changes in relative liver weights.
This document is a draft for review purposes only and does not constitute Agency policy,
3-17 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.025, 0.05, 0.1 mg Cr Vl/m3 as sodium
dichromate (Na2Cr2O7); 0, 0.063 mg Cr Vl/m3 as
pyrolized mixture of 3:2 Cr Vl/Cr III oxide (Cr5O12)
(dynamic whole-body chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and cyclone),
analytical method (photometric, by
diphenylcarbazine complexation), analytical
concentration, and MMD reported.
Histopathology - Oral
NTP (2008)
F344 Rat (50/sex/group)
Water: 0, 14.3, 57.3, 172, 516 ppm sodium
dichromate dihydrate; equivalent to 0, 0.21, 0.77,
2.1, 5.9mgCrVI/kg-d(M)
0, 0.24, 0.94, 2.4, 7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
Acharyaetal. (2001)
Wistar Rat, Male (5-6/group)
Water: 0, 20 ppm potassium dichromate;
equivalent to 0, 1.5 mg Cr Vl/kg-d
7 d/wk, 22 wk
Chopra etal. (1996)
Wistar Rat, Female (5-6/group)
Water: 0, 25 ppm potassium dichromate;
equivalent to 0, 1.4 mg Cr Vl/kg-d
7 d/wk, 22 wk
Results
Percent change from control by exposure group:
Exposure group Relative liver weight
Control (0 mg/m3)
Cr5O12(0.1mg/m3) 2.7
Na2Cr2O7 (0.025 mg/m3) No data provided
Na2Cr2O7 (0.05 mg/m3) No data provided
Na2Cr2O7 (0.1 mg/m3) 13.5*
Organ weights for liver at low and mid Na2Cr2O7 exposure groups were
measured but results not reported by authors due to lack of statistical
significance.
Incidence (percent) by exposure group:
Males
Histiocytic Chronic Basophilic
mgCrVI/kg-d cellular infiltration inflammation focus
0 1/50(2) 19/50(38) 22/50(44)
0.21 0/50(0) 25/50(50) 28/50(56)
0.77 2/49(4) 21/49(43) 29/49(60)*
2.1 5/50(10) 28/50(56)* 32/50(64)*
5.9 34/49(69)* 26/49(53) 30/49(61)
Females
Histiocytic Chronic
mgCrVI/kg-d cellular infiltration inflammation Fatty change
0 1/50(2) 12/50(24) 3/50(6)
0.24 5/50(10) 21/50(42)* 7/50(14)
0.94 21/50(42)* 28/50(56)* 10/50(20)*
2.4 42/50(84)* 35/50(70)* 13/50(26)*
7 47/50(94)* 39/50(78)* 16/50(32)*
Qualitative histopathology in treated group reported as:
Centrilobular and periportal vacuolation and necrosis in hepatocytes;
pronounced in periportal area.
Qualitative histopathology in treated group reported as:
Altered hepatic architecture in the periportal area; increased
sinusoidal space, vacuolation, and necrosis.
This document is a draft for review purposes only and does not constitute Agency policy,
3-18 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
NTP (2007)
F344 Rat (10/sex/group)
Water: 0, 62.5,125, 250, 500,1,000 ppm sodium
dichromate dihydrate; equivalent to 0,1.7, 3.5,
5.9, 11.2, 20.9 mg Cr Vl/kg-d (M/F)
7 d/wk, 3 mo
Incidence (%) by exposure group for females:
mg Cr Vl/kg-d
0
1.7
3.5
5.9
11.2
20.9
Histiocytic cellular
infiltration
0/10 (0)
3/10 (30)
6/10 (60)*
6/10 (60)*
9/10 (90)*
8/10 (80)*
Chronic focal
inflammation
3/10 (30)
5/10 (50)
2/10 (20)
7/10 (70)
2/10 (20)
10/10 (100)*
No statistically significant effects observed in males.
Rafael et al. (2007)
Wistar Rat, Male (9 control, 19 treated)
Water: 0, 20 ppm Cr VI equivalent to
0, 2.96 mgCr Vl/kg-d
7 d/wk, 10 wk
Qualitative histopathology in treated group reported as:
Increased intracellular space as a result of shrinkage, increased
degenerative alteration with vascularization, "little" focus of necrosis,
absence of polysaccharides and carbohydrates, fibrosis.
Meenakshi et al. (1989)
Wistar Rat, Male (10/group)
Gavage: 0,10 mg Cr Vl/kg-d as potassium
dichromate
7 d/wk, 60 d
Qualitative histopathology in treated group reported as:
Marked periportal accumulation of inflammatory cells, diffuse Kupffer
cell hyperplasia, focal necrosis, phagocytic cell infiltration.
NTP(2008)
B6C3F1 Mouse (50/sex/group)
Water: 0,14.3, 28.6, 85.7, 257.4 ppm sodium
dichromate dihydrate (M) or
0,14.3, 57.3,172, 516 ppm sodium dichromate
dihydrate (F); equivalent to
0, 0.38, 0.91, 2.4, 5.9 mg Cr Vl/kg-d (M)
0, 0.38, 1.4, 3.1, 8.7 mg Cr Vl/kg-d (F)
104 wk
Related reference: Stout et al. (2009)
Incidence (%) by exposure group for females:
mg Cr Vl/kg-d
0
0.38
1.4
3.1
8.7
Histiocytic cellular
infiltration
2/49 (4)
15/50 (30)*
23/50 (46)*
32/50 (64)*
45/50 (90)*
Chronic inflammation
16/49 (33)
21/50 (42)
22/50 (44)
27/50 (54)*
24/50 (48)
No significant effects observed in males.
NTP (2007)
B6C3F1, BALB/c, am3-C57BL/6 Mouse, Male (5-
10/group)
Water: 0, 62.5,125, 250 ppm sodium dichromate
dihydrate; equivalent to
0,2.8, 5.2, 8.7 mgCr Vl/kg-d
7 d/wk, 3 mo
Strain Comparison Study
Incidence (percent) by exposure group:
B6C3F1
mg Cr Vl/kg-d
0
2.8
5.2
8.7
Glycogen depletion
1/10(10)
2/10 (20)
9/10 (90)*
10/10 (100)*
am3-C57BL/6
Glycogen depletion
0/5 (0)
4/5 (80)*
5/5 (100)*
5/5 (100)*
No statistically significant effects observed in BALB/c strain.
This document is a draft for review purposes only and does not constitute Agency policy,
3-19 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
NTP (1996a)
BALB/c Mouse (24 males or 48 females/group, 5-
6 males or 12 females/group per timepoint)
Diet: 0, 15, 50, 100, 400 ppm potassium
dichromate; equivalent to
0, 1.1, 3.5, 7.4, 32.5 mg Cr Vl/kg-d (M) 0, 1.8, 5.6,
12.0, 48.4 mg Cr Vl/kg-d (F)
Sacrificed at 3, 6, 9 wk of treatment or after 8-wk
recovery period
Results
Incidence (percent) by exposure group:
Males
mg Cr Vl/kg-d Cytoplasmic vacuolation
0 0/6 (0)
1.1 0/6 (0)
3.5 1/6 (17)
7.4 2/5 (40)
32.5 2/6 (33)
Females
mg Cr Vl/kg-d Cytoplasmic vacuolation
0 1/12 (8)
1.8 0/12 (0)
5.6 3/12 (25)
12.0 2/12 (17)
48.4 4/12 (33)
Statistical significance and lesion severity not reported by study
authors.
Histopathology - Inhalation
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-body
chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and cyclone),
analytical method (atomic absorption
spectrometry; gravimetric filter), analytical
concentration, and MMD reported.
Related reference: Glaseretal. (1988)
Authors state normal histologic findings in kidney and liver but do not
provide data.
Gross Pathology - Inhalation
Nettesheimetal. (1971)
C57BL/6 Mouse (136 males/136 females)
0, 13 mg/m3 of calcium chromate dust (equivalent
to 4.33 mg Cr Vl/m3) (dynamic whole-body
chamber)
5 hr/d, 5 d/wk
lifespan (~2 yr)
Generation method (Wright dust feed), analytical
method (gravimetric filter), and analytical
concentration reported; MMAD not reported.
Methods: Nettesheimetal. (1970)
Markedly atrophied liver (incidence not specified).
Clinical chemistry - Oral
Kumar and Barthwal (1991)
Albino Rat, Male (10/group)
Gavage: 0, 50 mg Cr Vl/kg-d as potassium
chromate
7 d/wk, 30 d
Results presented as figures. Triglycerides, phospholipids, cholesterol,
and glucose were statistically significantly higher in treated animals
compared to controls after 30 days of treatment.
This document is a draft for review purposes only and does not constitute Agency policy,
3-20 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Meenakshi etal. (1989)
Wistar Rat, Male (6/group)
Gavage: 0,10 mg Cr Vl/kg-d as potassium
dichromate
7 d/wk, 60 d
Percent change from control by exposure group:
Total Phospho-
mg Cr Vl/kg-d cholesterol lipids Triglycerides Total lipids
0
10 36.4* 43.1* 26.5* 31.9*
mg Cr Vl/kg-d AST ALT GGT
0
10 51.6* 60.2* 57.5*
NTP (2007)
F344 Rat (10/sex/group)
Water: 0, 62.5,125, 250, 500,1,000 ppm sodium
dichromate dihydrate; equivalent to 0,1.7, 3.5,
5.9, 11.2, 20.9 mg Cr Vl/kg-d (M/F)
7 d/wk, 3 mo
Percent change from control by exposure group:
Males
mg Cr Vl/kg-d ALT at 3 Mo SDH at 3 Mo
0
1.7 180*
3.5 370*
5.9 356*
11.2 655*
20.9 95*
Females
ALT at 3 Mo
SDH at 3 Mo
77*
255*
229*
458*
90*
583*
241*
283*
284*
288*
359*
195*
268*
336*
368*
There were also statistically significant decreases in ALP, cholesterol,
and triglycerides, and increases in creatine kinase and bile acids in
males and females.
Chopra etal. (1996)
Wistar Rat, Female (5-6/group)
Water: 0, 25 ppm potassium dichromate;
equivalent to 0,1.4 mg Cr Vl/kg-d
7 d/wk, 22 wk
Percent change from control by exposure group:
mg Cr Vl/kg-d AST ALT ALP
0
1.4 50* 143* 167*
ACP
120*
Meenakshi etal. (1989)
Wistar Rat, Male (6/group)
Gavage: 0,10 mg Cr Vl/kg-d as potassium
dichromate
7 d/wk, 60 d
Percent change from control by exposure group:
mg Cr Vl/kg-d Glucose
0
10 58.0*
This document is a draft for review purposes only and does not constitute Agency policy,
3-21 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Krim et al. (2013)
Wistar Rat, Male (10/group)
Gavage: 0,15 mg/kg as potassium dichromate
7 d/wk, 30d
Percent change from control by exposure group:
mg/kg
0
15
mg/kg
0
15
Total lipids Triglycerides Cholesterol ALT
128*
AST
60*
70*
ALP
73*
56*
LDH
37*
48*
Geethaetal. (2003)
Sprague-Dawley Rat, Male (number/group not
reported)
Gavage: 0, 30 mg Cr Vl/kg-d given as potassium
dichromate
7 d/wk, 30 d
Statistically significant increases in ALT, AST, and creatinine
phosphokinase (figures only).
NTP (2007)
B6C3F1, BALB/c, am3-C57BL/6 Mouse (5-10
males/group)
Water: 0, 62.5,125, 250 ppm sodium dichromate
dihydrate; equivalent to
0, 2.8, 5.2 or 8.7 mg Cr Vl/kg-d (M)
7 d/wk, 3 mo
Strain Comparison Study
B6C3F1 mice: slight but statistically significant decreases in ALP, SDH,
and bile acids. No other significant changes in markers of liver
toxicity.
BALB/c mice: slight but statistically significant increases in ALT. No
other significant changes in markers of liver toxicity.
am3-C57BL/6 mice: statistically significant increase in ALT at the
highest dose. No other significant changes in markers of liver toxicity.
Clinical Chemistry - Inhalation
Kim et al. (2004)
Sprague-Dawley Rat, Male (5/group)
0, 0.2, 0.5,1.25 mg/m3 as CrO3 (dynamic whole-
body chamber)
6 hr/d, 5 d/wk
90 d
Generation method (mist generator), analytical
method (gravimetric filter, flame atomic
absorption spectrophotometry), and analytical
concentration reported; MMAD not reported.
Percent change from control by exposure group:
ALT
Glucose
-7.2 7.2*
-12.2 11.5*
-24.5* 5.1
No statistically significant effects on total bilirubin, AST, LDH, ALP,
glucose, or total cholesterol.
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic whole-body
chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and cyclone),
analytical method (atomic absorption
spectrometry; gravimetric filter), analytical
concentration, and MMD reported.
Related reference: Glaseretal. (1988)
Authors note no difference between exposed and control animals in
mean serum activity of GPT or AP or in total serum cholesterol.
Authors note statistically significant difference in serum triglyceride
and phospholipid contents at 0.200 mg/m3 compared to control but
data not provided.
This document is a draft for review purposes only and does not constitute Agency policy,
3-22 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.025, 0.05, 0.1 mg Cr Vl/m3 as sodium
dichromate (Na2Cr2O7); 0, 0.063 mg Cr Vl/m3 as
pyrolized mixture of 3:2 Cr Vl/Cr III oxide (Cr5O12)
(dynamic whole-body chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and cyclone),
analytical method (photometric, by
diphenylcarbazine complexation), analytical
concentration, and MMD reported.
Authors state no significant differences between alanine
aminotransferase and alkaline phosphatase activity, serum lipids,
triglycerides, phospholipids, or total cholesterol in any exposure group
compared to the controls (data not provided).
1
2
*Significantly different from control (p<0.05) as calculated by study authors.
Percent change from control calculated as (Treated - Control) -f Control x 100.
This document is a draft for review purposes only and does not constitute Agency policy,
3-23 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
100
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
10
• Statistically Significant O Not Statistically Significant
1 -
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1
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ra
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Relative Liver Weight
2
3
Figure 3-5. Exposure-response array of liver effects following inhalation exposure to hexavalent chromium.
This document is a draft for review purposes only and does not constitute Agency policy,
3-25 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.5. Immune System and Lymphatic System Effects
2
3
Table 3-4. Evidence pertaining to immune and lymphatic system effects
following oral or inhalation exposure to hexavalent chromium
Reference and study design
Results
Lymph Node, Pancreatic: Histopathology - Oral
NTP (2008)
F344 Rat (50/sex/group)
Water: 0, 14.3, 57.3, 172, 516 ppm sodium
dichromate dihydrate; equivalent to
0, 0.21, 0.77, 2.1, 5.9 mg Cr Vl/kg-d (M)
0, 0.24, 0.94, 2.4, 7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
NTP (2007)
F344 Rat (10/sex/group)
Water: 0, 62.5, 125, 250, 500, 1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 1.7, 3.5, 5.9, 11.2, 20.9 mg Cr Vl/kg-d
(M/F)
7 d/wk, 3 mo
Incidence (percent) by exposure group in females:
mg Cr Vl/kg-d Histiocytic cellular infiltration
0 17/29 (58.6)
0.24 20/36 (55.6)
0.94 23/30 (76.7)
2.4 32/34(94.1)*
7 27/33 (81.8)
No statistically significant effects observed in males.
Incidence (percent) by exposure group:
Males
Lymphoid
mg Cr Vl/kg-d Ectasia hyperplasia
0 0/10 (0) 0/10 (0)
1.7 0/10 (0) 0/10 (0)
3.5 0/10 (0) 0/10 (0)
5.9 0/10 (0) 3/10 (30)
11.2 1/10 (10) 3/10 (30)
20.9 10/10 (100)* 6/10 (60)*
Females
Lymphoid
mg Cr Vl/kg-d Ectasia hyperplasia
0 0/10 (0) 0/10 (0)
1.7 0/10 (0) 0/10 (0)
3.5 0/10 (0) 2/10 (20)
5.9 0/10 (0) 0/10 (0)
11.2 1/10 (10) 0/10 (0)
20.9 10/10 (100)* 10/10 (100)*
Histiocytic cellular
infiltration
0/10 (0)
5/10 (50)*
2/10 (20)
4/10 (40)*
5/10 (50)*
9/10 (90)*
Histiocytic cellular
infiltration
4/10 (40)
8/10 (80)
7/10 (70)
7/10 (70)
7/10 (70)*
9/10 (90)*
This document is a draft for review purposes only and does not constitute Agency policy,
3-26 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
NTP (2008)
B6C3F1 Mouse (50/sex/group)
Water: 0, 14.3, 28.6, 85.7, 257.4 ppm
sodium dichromate dihydrate (M)
0, 14.3, 57.3, 172, 516 ppm sodium
dichromate dihydrate (F); equivalent to
0, 0.38, 0.91, 2.4, 5.9 mg Cr Vl/kg-d (M)
0, 0.38, 1.4, 3.1, 8.7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
Results
Incidence (percent) by exposure group:
Males Histiocytic cellular
mg Cr Vl/kg-d
0
0.38
0.91
2.4
5.9
Females
mg Cr Vl/kg-d
0
0.38
1.4
3.1
8.7
infiltration
0/5 (0)
2/13 (15)
2/10 (20)
5/8 (63)*
12/16 (75)*
Histiocvtic cellular
infiltration
0/14 (0)
1/12 (8)
2/15 (13)
7/14 (50)*
8/13 (62)*
Lymph Node, Mesenteric: Histopathology-Oral
NTP (2008)
F344 Rat (50/sex/group)
Water: 0, 14.3, 57.3, 172, 516 ppm sodium
dichromate dihydrate; equivalent to
0, 0.21, 0.77, 2.1, 5.9 mg Cr Vl/kg-d (M)
0, 0.24, 0.94, 2.4, 7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
NTP (2007)
B6C3F1 Mouse (10/sex/group)
Water: 0, 62.5, 125, 250, 500, 1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 3.1, 5.3, 9.1, 15.7, 27.9 mg Cr Vl/kg-d
(M/F)
7 d/wk, 3 mo
Incidence (percent) by exposure group:
Males
mg Cr Vl/kg-d
0
0.21
0.77
2.1
5.9
Females
mg Cr Vl/kg-d
0
0.24
0.94
2.4
7
Histiocvtic cellular infiltration
13/49 (26.5)
11/50 (22)
30/49 (61.2)*
39/50(78)*
41/49 (83.7)*
Histiocvtic cellular infiltration
21/50 (42)
18/50 (36)
27/50 (54)
36/50(72)*
42/50(84)*
Incidence (percent) by exposure group:
Males:
mg Cr Vl/kg-d Histiocvtic cellular infiltration
0
3.1
5.3
9.1
15.7
27.9
0/10 (0)
0/9 (0)
4/9 (44)*
6/8 (75)*
3/8 (38)
8/10 (80)*
Hemorrhage
2/49(4.1)
7/50 (14)
9/49 (18.4)*
8/50 (16)*
17/49 (34.7)*
Hemorrhage
11/50 (22)
13/50 (26)
16/50 (32)
14/50 (28)
21/50 (42)*
Females:
Histiocvtic cellular infiltration
0/10 (0)
0/10 (0)
6/10 (60)*
6/10 (60)*
4/9 (44)*
9/10 (90)*
This document is a draft for review purposes only and does not constitute Agency policy,
3-27 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
NTP (2007)
B6C3F1, BALB/c, am3-C57BL/6 Mouse,
Male (5-10/group)
Water: 0, 62.5,125, 250 ppm sodium
dichromate dihydrate; equivalent to
0, 2.8, 5.2, 8.7 mg Cr Vl/kg-d (M)
7 d/wk, 3 mo
Strain Comparison Study
Incidence (percent) by exposure group in am3-C57BL/6:
mg Cr Vl/kg-d Histiocytic cellular infiltration
0/5 (0)
0/5 (0)
0/5 (0)
4/5 (80)*
0
2.8
5.2
8.7
No statistically significant effects observed in B6C3F1 or BALB/c strains.
Immune System Effects - Inhalation
Kim et al. (2004)
Sprague-Dawley Rat, Male (5/group)
0, 0.2, 0.5,1.25 mg/m3as CrO3 (dynamic
whole-body chamber)
6 hr/d, 5 d/wk
7 d/wk, 90 d
Generation method (mist generator),
analytical method (gravimetric filter, flame
atomic absorption spectrophotometry),
and analytical concentration reported;
MMAD not reported.
Authors report macrophage aggregation and foamy cells in alveolar region in
"all animals of the 1.25 mg/m3 treated group, but in only a few animals of
the 0.5 mg/m3 treated group and none in the 0.2 mg/m3 group."
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic
whole-body chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and
cyclone), analytical method (atomic
absorption spectrometry; gravimetric
filter), analytical concentration, and MMD
reported.
Related reference: Glaseretal. (1988)
Percent change from control by exposure group:
Serum immunoglobulin levels
8.3
66.7*
91.7*
0
Values approximated from Figure 2. Text states that "the differences in the
mean total immunoglobulin levels between control and experimental groups
became significant at exposures above 25 u.g/m3 Cr. Aerosols with chromium
concentrations higher than 100 u.g/m3 produced depression of the
stimulating effect."
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.025, 0.05, 0.1 mg Cr Vl/m3 as sodium
dichromate; 0, 0.063 mg Cr Vl/m3 as
pyrolized mixture of 3:2 Cr VI/Cr(lll) oxide
(dynamic whole-body chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and
cyclone), analytical method (photometric,
by diphenylcarbazine complexation),
analytical concentration, and MMD
reported.
Mean serum immunoglobulin was measured at 6,15, and 24 months; lower
levels were measured in all exposure groups compared to control but only
significant (p <0.001) for Cr5O12-exposed groups at 6 months (data not
provided).
This document is a draft for review purposes only and does not constitute Agency policy,
3-28 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.200 mg Cr Vl/m3 as Na2Cr2O7 aerosol
exposure (dynamic whole-body chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and
cyclone), analytical method (atomic
absorption spectrometry; gravimetric
filter), analytical concentration, and MMD
reported.
Related reference: Glaseretal. (1988)
Percent change from control by exposure group for mitogen-simulated T-
lymphocyte response to concanavalin:
mg/m3 15 ug/ml concanavalin 30 ug/ml concanavalin
0
0.200 53.1* 51.4*
Values were approximated from a figure, actual data not provided.
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050 mg Cr Vl/m3 (28 and 90 d)
and 0.200 mg Cr Vl/m3 (90 d only) as
Na2Cr2O7 aerosol exposure (dynamic
whole-body chamber)
22 hr/d, 7 d/wk
28 and 90 d
Generation method (jet nebulizer and
cyclone), analytical method (atomic
absorption spectrometry; gravimetric
filter), analytical concentration, and MMD
reported.
Related reference: Glaseretal. (1988)
Percent change from control by exposure group:
SRBC antibody response by spleen cells
28 d
52.2*
34.8*
Not measured
in vitro phagocytosis of 2 urn latex particles
28 d
Not reported
462.5*
Not measured
90 d
60.5*
181*
128*
90 d
159.5*
439.7*
-73.2*
Values were approximated from a figure, actual data not provided.
Spleen Weight - Oral
Geethaetal. (2003)
Sprague-Dawley Rat, Male (number/group
not reported)
Gavage: 0, 30 mg Cr Vl/kg-d given as
potassium dichromate
7 d/wk (assumed), 30 d
Percent change from control by exposure group:
mg Cr
Vl/kg-d Relative spleen weight
0
30 47.6*
This document is a draft for review purposes only and does not constitute Agency policy,
3-29 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
NTP (2007)
F344 Rat (10/sex/group)
Water: 0, 62.5, 125, 250, 500, 1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 1.7, 3.5, 5.9, 11.2, 20.9 mg Cr Vl/kg-d
(M/F)
7 d/wk, 3 mo
NTP (2007)
B6C3F1 Mouse (10/sex/group)
Water: 0, 62.5, 125, 250, 500, 1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 3.1, 5.3, 9.1, 15.7, 27.9 mg Cr Vl/kg-d
(M/F)
7 d/wk, 3 mo
Percent change
Males
mg Cr Vl/kg-d
0
1.7
3.5
5.9
11.2
20.9
Females
mg Cr Vl/kg-d
0
1.7
3.5
5.9
11.2
20.9
Percent change
Males
mg Cr Vl/kg-d
0
3.1
5.3
9.1
15.7
27.9
Females
mg Cr Vl/kg-d
0
3.1
5.3
9.1
15.7
27.9
Results
from control by exposure group:
Absolute spleen weight
—
-6.3
-3.1
-6.3
-17.2*
-6.3*
Absolute spleen weight
-
7.3
4.9
7.3
7.3
7.3
from control by exposure group:
Absolute spleen weight
—
-1.5
-5.9
-5.9
-7.4
-11.8
Absolute spleen weight
-
8.1
8.1
9.5
-4.1
0
Relative
—
-4.6
-5.7
-6.7*
-12.9*
3.1
Relative
-
-3.8
1.9
4.7
6.1*
12.7*
Relative
—
4.3
4.5
10.6
16.5*
10.5*
Relative
-
6.8
16.3*
14.1
7.7
13.6
spleen weight
spleen weight
spleen weight
spleen weight
This document is a draft for review purposes only and does not constitute Agency policy,
3-30 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
NTP (2007)
B6C3F1, BALB/c, am3-C57BL/6 Mouse (5-
10 males/group)
Water: 0, 62.5,125, 250 ppm sodium
dichromate dihydrate; equivalent to
0, 2.8, 5.2 or 8.7 mg Cr Vl/kg-d (M)
7 d/wk, 3 mo
Strain Comparison Study
Percent change from control by exposure group:
B6C3F1
Absolute spleen weight
-7.1
-8.2
-20.0*
Absolute spleen weight
-4.5
-6.7
-9.0
Absolute spleen weight
-7.3
-3.7
-22.0*
Relative spleen weight
-5.9
1.8
3.8
Relative spleen weight
-2.3
-0.9
1.7
Relative spleen weight
9.2
15.0
21.2*
Spleen Weight - Inhalation
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic
whole-body chamber)
22 hr/d, 7 d/wk
28 d
Generation method (jet nebulizer and
cyclone), analytical method (atomic
absorption spectrometry; gravimetric
filter), analytical concentration, and MMD
reported.
Related reference: Glaseretal. (1988)
Authors state that spleen weights were statistically significantly increased
after 28 day inhalation exposure to chromate aerosol concentrations above
0.025 mg/m3 Cr VI but data were not provided.
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic
whole-body chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and
cyclone), analytical method (atomic
absorption spectrometry; gravimetric
filter), analytical concentration, and MMD
reported.
Related reference: Glaseretal. (1988)
Percent change from control by exposure group:
3
Relative spleen weight
0
33.3*
50.0*
41.7*
This document is a draft for review purposes only and does not constitute Agency policy,
3-31 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.025, 0.05, 0.1 mg Cr Vl/m3 as sodium
dichromate (Na2Cr2O7); 0, 0.063 mg Cr
Vl/m3 as pyrolized mixture of 3:2 Cr Vl/Cr
III oxide (Cr5O12) (dynamic whole-body
chamber)
22 hr/d, 7 d/wk
72 wk
(dynamic whole-body chamber)
Generation method (jet nebulizer and
cyclone), analytical method (photometric,
by diphenylcarbazine complexation),
analytical concentration, and MMD
reported.
Organ weights for kidney, adrenal glands, spleen, and testes at all exposure
groups and for lung and liver at low and mid Na2Cr2O7 exposure groups were
measured but results not reported (assumed to be not significant).
Kim et al. (2004)
Sprague-Dawley Rat, Male (5/group)
0, 0.2, 0.5,1.25 mg/m3as CrO3 (dynamic
whole-body chamber)
6 hr/d, 5 d/wk
90 d
Generation method (mist generator),
analytical method (gravimetric filter, flame
atomic absorption spectrophotometry),
and analytical concentration reported;
MMAD not reported.
Authors report no statistically significant changes in relative spleen weights
but data were not provided.
Nettesheimetal. (1971)
C57BL/6 Mouse (136 males/136 females)
0,13 mg/m3 of calcium chromate dust
(equivalent to 4.33 mg Cr Vl/m3) (dynamic
whole-body chamber)
5 hr/d, 5 d/wk
lifespan (~2 yr)
Generation method (Wright dust feed),
analytical method (gravimetric filter), and
analytical concentration reported; MMAD
not reported.
Methods: Nettesheimetal. (1970)
Atrophied spleen (incidence not specified).
*Significantly different from control (p<0.05) as calculated by study authors.
Percent change from control calculated as (Treated - Control) 4- Control x 100.
This document is a draft for review purposes only and does not constitute Agency policy,
3-32 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
100
• Statistically Significant O Not Statistically Significant
• • * • o
• • • • o •
O O 11(1
Oil < 1 O 1141
1
9
0 • O •
o o
o • °
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c
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^Z^ZQ?|_ Q^Q.^.-tZoTi X *3
Histiocytic Infiltration Other Effects Histiocytic Infiltration Other Effects
Lymph Node, Pancreatic Histopathology Lymph Node, Mesenteric: Histopathology
mils 1 S 1
§ rT ^ 'E £. g .
-f § " S 8 H z
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ra z z 2-~ Ir £
-c tz ^ o
t5 » is
i
Relative Spleen Weights
I
)
)
QJ
'I
10
0.1
2
3
4
Figure 3-6. Exposure-response array of immune and lymphatic system effects following oral exposure to
hexavalent chromium. [A]: am3-C57BL/6 strain of mouse; [B]: B6C3F1; [C]: BALB/c.
This document is a draft for review purposes only and does not constitute Agency policy.
3-33
DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
t Statistically Significant O Not Statistically Significant
a
i1
4->
S
8
a
•0.1
0.01
O I
ob i
_O tf)
no co
o *
c "-1
1 "S
.i £
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E IS
% 5
n> ro
re gj
tr u-»
Is
re :-
£»
O 0)
> S
c J5
W
Immune outcomes
_
o
Spleen Weight
2
3
4
Figure 3-7. Exposure-response array of immune and lymphatic system effects following inhalation exposure to
hexavalent chromium.
This document is a draft for review purposes only and does not constitute Agency policy,
3-34 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.6. Hematological Effects
2
3
Table 3-5. Evidence pertaining to hematological effects following oral or
inhalation exposure to hexavalent chromium
Reference and study design
Oral
NTP (2008)
F344 Rat (50/sex/group)
Water: 0, 14.3, 57.3, 172, 516 ppm
sodium dichromate dihydrate;
equivalent to
0, 0.21, 0.77, 2.1, 5.9 mg Cr Vl/kg-d (M)
0, 0.24, 0.94, 2.4, 7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
Results
Percent change from control by exposure group in males at 12
mgCr Vl/kg-d Hgb MCV MCH MCHC
o
0.21 -2.5 -0.4 -1.2 -0.6
0.77 -1.3 -1.3 -2.4* -0.9
2.1 -1.3 -2.3* -4.7* -2.2*
5.9 -3.2* -5.1* -7.6* -2.5*
There were intermittent decreases in hematocrit and increase
reticulocytes, nucleated erythrocytes, and platelets that were
months. There were no consistent changes in WBCs.
Hematological data not collected in female rats.
mo:
RBC
-1.1
1.4
3.7
5.1*
s in
resolved by 12
This document is a draft for review purposes only and does not constitute Agency policy,
3-35 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
NTP (2007)
F344 Rat (10/sex/group)
Water: 0, 62.5, 125, 250, 500, 1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 1.7, 3.5, 5.9, 11.2,
20.9 mg Cr Vl/kg-d (M/F)
7 d/wk, 3 mo
Kumar and Barthwal (1991)
Albino Rat, Male (10/group)
Gavage: 0, 50 mg Cr Vl/kg-d as potassium
chromate
7 d/wk, 30 d
Results
Percent change from control by exposure group:
Male
Hct
mgCrVI/kg-d (automated) Hgb RBC Reticulocytes
o
1.7 -1.1 -0.7 1.8* 4.3
3.5 -1.5 -2.0 4.2* -4.3
5.9 -2.4 -5.9* 14.3* 4.3
11.2 -6.3* -13.1* 22.4* 0.0
20.9 -33.0* -28.8* -4.1* 34.8*
Nucleated
mgCrVI/kg-d erythrocytes MCV MCH MCHC
o
1.7 200.0 -2.9* -2.3* 1.8
3.5 0.0 -5.4* -6.4* -0.9
5.9 0.0 -14.3* -17.9* -4.2*
11.2 100.0 -23.4* -28.9* -7.2*
20.9 1100.0* -30.5* -24.9* 8.7*
Female
Hct
mgCrVI/kg-d (automated) Hgb RBC Reticulocytes
o
1.7 3.6 1.3 3.6* 29.4*
3.5 -0.5 -2.0 1.2* 23.5*
5.9 -3.2* -5.9* 2.0* 23.5*
11.2 -3.2* -7.2* 7.6* 23.5*
20.9 -13.1* -21.1* 15.9* 41.2*
Nucleated
mgCr Vl/kg-d erythrocytes MCV MCH MCHC
o
1.7 -63.3 0.0 -2.7* -2.3*
3.5 33.3 -1.7* -3.3* -1.7*
5.9 -33.3 -5.3* -8.2* -2.9*
11.2 -100.0 -9.9* -13.6* -4.3*
20.9 -63.3 -25.0* -32.1* -9.6*
There was also a significant increase in platelets in both males and females, but
NTP stated that a platelet estimate performed on blood smears indicate that
there was no increase at Week 14.
Results presented as figures. Hemoglobin, red blood cells, and plasma
corpuscular volume were statistically significantly lower in treated group
compared to control at 30 days. White blood cells in treated animals were
lower than controls but the measurement did not achieve statistical
significance.
This document is a draft for review purposes only and does not constitute Agency policy,
3-36 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Krim et al. (2013)
Wistar Rat, Male (10/group)
Gavage: 0,15 mg/kg as potassium
dichromate
7 d/wk, 30 d
Percent change from control by exposure group:
mg/kg potassium dichromate RBC Hgb Hct
0
15 -25* -15* -32*
There were no significant changes in WBC, MCHC, or platelets.
MCV
-9*
NTP (2007)
B6C3F1, BALB/c, am3-C57BL/6 Mouse,
Male (5-10/group)
Water: 0, 62.5,125, 250 ppm sodium
dichromate dihydrate; equivalent to
0, 2.8, 5.2 or 8.7 mg Cr Vl/kg-d (M)
7 d/wk, 3 mo
Strain Comparison Study
Percent change from control by exposure group for MCH at 3 mo:
mg Cr Vl/kg-d B6C3F1 BALB/c am3-C57BL/6
0
-3* -3* -2*
.4* .5* .4*
-7* -7* -6*
Percent change from control by exposure group for MCV at 3 mo:
mg Cr Vl/kg-d B6C3F1 BALB/c am3-C57BL/6
0
2.8 -2* -2* -3
5.2 -3 -4 -5*
2.8
5.2
8.7
8.7
-6
-5
-12
NTP (1996a)
BALB/c Mouse (24 males or 48
females/group, 5-6 males or 12
females/group pertimepoint)
Diet: 0,15, 50,100, 400 ppm potassium
dichromate; equivalent to
0,1.1, 3.5, 7.4, 32.5 mg Cr Vl/kg-d (M) 0,
1.8, 5.6,12.0, 48.4 mg Cr Vl/kg-d (F)
Sacrificed at 3, 6, 9 wk of treatment or
after 8-wk recovery period
Percent change from control by exposure group:
Male
MCV at 9 weeks
mg Cr Vl/kg-d
0
1.1
3.5
7.4
32.5
Female
mg Cr Vl/kg-d
0
1.8
5.6
12.0
48.4
-1.4
-1.2
-2.1
-4.3*
MCV at 9 weeks
0.0
0.2
-1.0
-2.0*
MCH was significantly decreased in males but not females at Week 9. There
were no other significant changes in hematology parameters ay Week 9. The
MCV resolved after the 8-week recovery period in females, but was increased
in males.
This document is a draft for review purposes only and does not constitute Agency policy,
3-37 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
NTP (2007)
B6C3F1 Mouse (10/sex/group)
Water: 0, 62.5,125, 250, 500,1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 3.1, 5.3, 9.1, 15.7, 27.9 mg Cr Vl/kg-
d (M/F)
7 d/wk, 3 mo
Percent change from control by exposure group:
Male
mg Cr Vl/kg-d MCV MCH
0
3.1
5.3
9.1
15.7
27.9
Female
-1.8*
-3.6*
-4.9*
-5.6*
-7.3*
MCV
-2.0*
-3.3*
-4.6*
-5.9*
-7.8*
MCH
Hgb
-4.9
0
-3.1
-4.3
-5.5
Hgb
mg Cr Vl/kg-d
0
3.1
5.3
9.1
15.7
27.9
There were no significant changes in hematocrit, RBCs, nucleated erythrocytes,
platelets, or WBCs in either males or females. Females had a slight but
significant decrease in MCHC that was not observed in males.
-0.9
-1.9*
-3.9*
-5.8*
-7.3*
-1.3*
-3.2*
-5.7*
-7.6*
-9.5*
-1.3
0.6
-0.6
-3.2*
-4.5*
NTP(2008)
B6C3F1 Mouse (50/sex/group)
Water: 0, 14.3, 28.6, 85.7, 257.4 ppm
sodium dichromate dihydrate (M)
0,14.3, 57.3,172, 516 ppm sodium
dichromate dihydrate (F); equivalent to
0, 0.38, 0.91, 2.4, 5.9 mg Cr Vl/kg-d (M)
0, 0.38, 1.4, 3.1, 8.7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
Percent change from control by exposure group:
Female
mg Cr Vl/kg-d
0
0.38
1.4
3.1
8.7
RBC
1.5
2.0
3.9*
7.5*
MCV
0.0
-1.3
-3.6*
-6.4*
MCH
1.3
0.0
-2.6*
-7.1*
There were intermittent increases in WBC and decreases in MCHC that were
resolved by 12 months. No changes were observed in hemoglobin,
reticulocytes, or nucleated erythrocytes. There was a decrease in platelets
observed only after 12 months.
Hematological data not collected in male mice.
Shrivastava et al. (2005)
Swiss Mouse, sex not specified (12-
24/group)
Water: 0, 250 ppm as potassium
dichromate; equivalent to 0,
14.8 mg/kg-d
9 wk
Percent change from control by exposure group:
mg Cr Vl/kg-d 3 wk: platelets 9 wk: platelets
0
14.8 68* 99*
WBCs were significantly decreased at 3 wk, but not at 6 or 9 wk; RBCs were
significantly increased at 3 wk, but not at 6 or 9 wk; at 9 wk there was a
significant decrease in MCV and significant increase in Hgb and Hct, but no
change in MCHC.
This document is a draft for review purposes only and does not constitute Agency policy,
3-38 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Inhalation
Glaseretal. (1990)
Wistar Rat, Male (10/group)
0, 0.050, 0.10, 0.20, 0.40 mg Cr Vl/m3 as
Na2Cr2O7 aerosol exposure (dynamic
whole-body chamber)
22 hr/d, 7 d/wk
30 d, 90 d, or 90 d with 30 d recovery
Generation method (cyclone nebulizer),
analytical concentration, and MMD
reported; analytical method not
reported.
Percent change from control for leukocytes in blood (10 /L) by exposure group:
30 d
83.9*
87.5*
132.1*
248.2*
90 d
-84.3*
70.4*
255.6*
374.1*
90 d with 30 d recovery
-11.2
-5.6
3.4
27.0
Glaseretal. (1985)
Wistar Rat, Male (10/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3
as Na2Cr2O7 aerosol exposure (dynamic
whole-body chamber)
22 hr/d, 7 d/wk
90 d
Generation method (jet nebulizer and
cyclone), analytical method (atomic
absorption spectrometry; gravimetric
filter), analytical concentration, and
MMD reported.
Related reference: Glaseretal. (1988)
Authors state that red and white blood cell counts were not affected but data
were not provided.
Glaseretal. (1986)
Wistar Rat, Male (40/control,
20/treatment group)
0, 0.025, 0.05, 0.1 mg Cr Vl/m3 as sodium
dichromate(Na2Cr2O7); 0, 0.063 mg Cr
Vl/m3 as pyrolized mixture of 3:2 Cr Vl/Cr
III oxide (Cr5O12) (dynamic whole-body
chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and
cyclone), analytical method
(photometric, by diphenylcarbazine
complexation), analytical concentration,
and MMD reported.
Percent change from control by exposure group:
Group 17-18 mo: leukocyte count
Control (0 mg/m3)
Cr5O12(0.1mg/m3) 35.6*
Authors stated that there were no statistically significant differences in
hematological parameters between the controls and Na2Cr2O7-exposed
groups, no data provided. Authors note statistically significant increases in red
blood cell count, hematocrit, and blood hemoglobin levels in the Cr5O12-
exposed group at 27 mo but no data were provided.
This document is a draft for review purposes only and does not constitute Agency policy,
3-39 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Kim et al. (2004)
Sprague-Dawley Rat, Male (5/group)
0, 0.2, 0.5,1.25 mg/m3as CrO3 (dynamic
whole-body chamber)
6 hr/d, 5 d/wk
90 d
Generation method (mist generator),
analytical method (gravimetric filter,
flame atomic absorption
spectrophotometry), and analytical
concentration reported; MMAD not
reported.
Percent change from control by exposure group:
Hgb
-5.3
-6*
-7.9*
Hct
-8.2*
-6.8
-11*
Mean RBC
count
-3.4
-4.6
-8*
No statistically significant effects on WBC, MCV, MVHC, or platelets.
1
2
3
*Significantly different from control (p<0.05) as calculated by study authors.
Percent change from control calculated as (Treated - Control) 4- Control x 100.
This document is a draft for review purposes only and does not constitute Agency policy,
3-40 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
100
• Statistically Significant o Not Statistically Significant
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ro
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Figure 3-8. Exposure-response array of hematological effects following oral exposure to hexavalent chromium.
[Kumar & E., 1991] denotes Kumar and Barthwal (1991). [A]: am3-C57BL/6 strain of mouse; [B]: B6C3F1; [C]:
BALB/c.
This document is a draft for review purposes only and does not constitute Agency policy,
3-41
DRAFT— DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
10
• Statistically Significant
o Not Statistically Significant
§
'I
I
3 o.i
0.01
RBC
(0
s
E
'
MCV
Hemoglobin
6
E
Leukocytes (WBC)
Other
2
3
4
Figure 3-9. Exposure-response array of hematological effects following inhalation exposure to hexavalent
chromium.
This document is a draft for review purposes only and does not constitute Agency policy.
3-42
DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.7. Male Reproductive Effects
2
3
Table 3-6. Evidence pertaining to male reproductive effects following oral or
inhalation exposure to hexavalent chromium
Reference and study design
Results
Male Reproductive Organ Weights - Oral
NTP(2007)
F344 Rat (10 males/group)
Water: 0, 62.5,125, 250, 500,1,000 ppm
sodium dichromate dihydrate; equivalent
to 0,1.7, 3.5, 5.9,11.2, 20.9 mg Cr Vl/kg-d
7 d/wk, 3 mo
No statistically significant effects observed on absolute male testis weight.
Chowdhuryand Mitra (1995)
Charles Foster Rat (10 males/group)
Gavage: 0, 20, 40, 60 mg Cr Vl/kg-d;
administered as sodium dichromate
7 d/wk, 90 d
Percent change from control by exposure group:
mg Cr Vl/kg-d Testis: absolute weight
0
20 -2.7
40 -27.7*
60 -35.0*
NTP(1996b)
Sprague-Dawley Rat (24 males/group; 6
males/group/timepoint)
Diet: 0,15, 50,100, 400 ppm potassium
dichromate; equivalent to
0, 0.35, 1.1, 2.1, 8.5 mg Cr Vl/kg-d
Sacrificed after 3, 6, 9 wks of treatment or
after 8-wk recovery period
No statistically significant effects observed on male testis weight.
NTP(2007)
B6C3F1 Mouse (10 males/group)
Water: 0, 62.5,125, 250, 500,1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 3.1, 5.3, 9.1,15.7, 27.9 mg Cr Vl/kg-d
7 d/wk, 3 mo
No statistically significant effects observed on male absolute testis weight.
NTP(2007)
B6C3F1, BALB/c, am3-C57BL/6 Mouse (5-
10 males/group)
Water: 0, 62.5,125, 250 ppm sodium
dichromate dihydrate; equivalent to
0, 2.8, 5.2 or 8.7 mg Cr Vl/kg-d
7 d/wk, 3 mo
Strain Comparison Study
No treatment-related effects were observed for weights of left cauda, left
epididymis, and left testis weight; the statistically significant (11%) decrease
observed in the absolute testes weight of am3-C57BL/6 mice was attributed
to a 36% decrease in body weight.
This document is a draft for review purposes only and does not constitute Agency policy,
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-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
NTP (1997)
BALB/c Mouse (20 males/group)
Continuous Breeding Protocol: FO animals
exposed for 13 wks total, 1 wk prior to and
12 wks during cohabitation. After
cohabitation, FO breeding pairs were
separated and continued on study diets.
Diet: 0,100, 200, 400 ppm potassium
dichromate (equivalent to 0,17.6, 35.3,
141.2 ppm Cr VI)
(FO): 0,19.4, 38.6, 85.7 mg potassium
dichromate/kg-d (equivalent to 0, 6.8,
13.6, 30.3 mgCrVI/kg-d)
(Fl): 0, 22.4, 45.5,104.9 mg potassium
dichromate/kg-d (equivalent to 0, 7.9,
16.1, 37.1 mgCrVI/kg-d)
No effects on FO reproductive organ weights (right testis weight, right
epididymis weight, right cauda epididymis weight, prostate weight, seminal
vesicle weight).
No statistically significant effects on Fl reproductive organ weights (right
testis weight, right epididymis weight, right cauda epididymis weight,
prostate weight, seminal vesicle weight).
Treatment-related decrease in maternal weights at delivery reported for
some of the litters.3 No treatment-related differences reported in pregnancy
index.
NTP (1996a)
BALB/c Mouse (24 males/group, 5-6
males/group pertimepoint)
Diet: 0,15, 50,100, 400 ppm potassium
dichromate; equivalent to
0,1.1, 3.5, 7.4, 32.5 mg Cr Vl/kg-d
Sacrificed after 3, 6, 9 wks of treatment or
after 8-wk recovery period
No statistically significant effects observed on male testis weight.
Zahidetal. (1990)
BALB/c Mouse (7 males/group)
Diet: 0,100, 200, 400 mg potassium
dichromate/kg diet equivalent to
0, 6.4,12.7, 25.5 mg CrVI/kg-d (calculated)
35 d
Testes and epididymis weights were stated to be comparable across all
treatment groups but data were not provided.
Yousefetal. (2006)
New Zealand White Rabbit (6
males/group)
Gavage: 0, 5 mg potassium
dichromate/kg-d; equivalent to 0, 3.6 mg
Cr Vl/kg-d
7 d/wk, 10 wk
Percent change from control by exposure group:
mg Cr Vl/kg-d Testis: relative weight Epididymis: relative weight
0
3.6 -22.2* -22.2*
This document is a draft for review purposes only and does not constitute Agency policy,
3-44 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Testis: Weight-Inhalation
Glaseretal. (1986)
Wistar Rat (40 males/control, 20
males/treatment group)
0, 0.025, 0.05, 0.1 mg Cr Vl/m3 as sodium
dichromate (Na2Cr2O7); 0, 0.063 mg Cr
Vl/m3 as pyrolized mixture of 3:2 Cr Vl/Cr
III oxide (Cr5O12) (dynamic whole-body
chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and
cyclone), analytical method (photometric,
by diphenylcarbazine complexation),
analytical concentration, and MMD
reported.
Authors stated no statistically significant effects observed but data were not
provided.
Kim et al. (2004)
Sprague-Dawley Rat (5 males/group)
0, 0.2, 0.5,1.25 mg/m3as CrO3 (dynamic
whole-body chamber)
6 hr/d, 5 d/wk
91 d
Generation method (mist generator),
analytical method (gravimetric filter, flame
atomic absorption spectrophotometry),
and analytical concentration reported;
MMAD not reported.
There were no statistically significant changes in relative testes weights.
Male Reproductive Organ Histopathology - Oral
Chowdhuryand Mitra (1995)
Charles Foster Rat (10 males/group)
Gavage: 0, 20, 40, 60 mg Cr Vl/kg-d;
administered as sodium dichromate
7 d/wk, 90 d
Percent change from control by exposure group for testis endpoints:
Seminiferous Leydig cell Leydig cell
tubular Stage-7 population - population
mg Cr Vl/kg-d diameter spermatid entry 1 - entry 2
0
20
40
60
mg Cr Vl/kg-d
0
20
40
60
-0.8
-10.8*
-15.3*
Pachytene
spermatocyte
-3.6
-25.7*
-28*
-0.2
-19.5*
-45*
-3.7
-21.4*
-37.3*
0
-12.1*
-19.7*
Resting Spermato-
spermatocyte gonia
-2.3
-3.3
-5*
-1
-0.8
-0.6
Study authors provided two separate entries for leydig cell population.
This document is a draft for review purposes only and does not constitute Agency policy,
3-45 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
NTP (2007)
F344 Rat (10 males/group)
Water: 0, 62.5, 125, 250, 500, 1,000 ppm
sodium dichromate dihydrate; equivalent
to 0, 1.7, 3.5, 5.9, 11.2, 20.9 mg Cr Vl/kg-d
7 d/wk, 3 mo
NTP (1996a)
BALB/c Mouse (24 males/group, 5-6
males/group pertimepoint)
Diet: 0, 15, 50, 100, 400 ppm potassium
dichromate; equivalent to
0, 1.1, 3.5, 7.4, 32.5 mg Cr Vl/kg-d
Sacrificed after 3, 6, 9 wks of treatment or
after 8-wk recovery period
Zahidetal. (1990)
BALB/c Mouse (7 males/group)
Diet: 0, 100, 200, 400 mg potassium
dichromate/kg diet equivalent to
0, 6.4, 12.7, 25.5 mg CrVI/kg-d (calculated)
35 d
Results
No statistically significant effects observed upon microscopic examination of
testis.
No statistically significant effects observed on male reproductive organ
histopathology (testes and epididymis examined for Sertoli nuclei and
preleptotene spermatocyte counts in Stage X or XI tubules; sperm analyzed
for chromatin structure).
Undegenerated
Degenerated tubules without
mg CrVI/kg- tubules spermatogonia
d (incidence (%) (incidence (%)
0 0/1400 (0) 18/90 (20)
6.4 21/1774 (1.2)* 45/90 (50)*
12.7 26/1129 (2.3)* 54/90 (60)*
25.5 33/1372 (2.4)* 81/90 (90)*
Resting
Spermato- spermato-
gonia cytes
(% change) (% change)
-80* 159*
-89* 151*
-95* 192*
Male Reproductive Organ Histopathology - Inhalation
Glaseretal. (1985)
Wistar (TNO-W-74) Rat (10 males/group)
0, 0.025, 0.050, 0.100, 0.200 mg Cr Vl/m3
as Na2Cr2O7 aerosol exposure (dynamic
whole-body chamber)
22 hr/d, 7 d/wk
28 d and 90 d
Generation method (jet nebulizer and
cyclone), analytical method (atomic
absorption spectrometry; gravimetric
filter), concentration, and MMD reported.
Related reference: Glaseretal. (1988)
No statistically significant effects observed.
Sperm and Reproductive Parameters - Oral
Li et al. (2001)
Wistar Rat (8-11 males/group)
Gavage: 0, 10, 20 mg CrO3/kg-d;
equivalent to 0, 5.2, 10.4 mg Cr Vl/kg-d
6 d (sacrificed after 6 wk)
Percent change from control by exposure group:
mg Cr Vl/kg-d Sperm count
0
5.2 -75.5*
10.4 -80*
Sperm abnormality
142.9*
176.4*
This document is a draft for review purposes only and does not constitute Agency policy,
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
NTP(2007)
B6C3F1, BALB/c, am3-C57BL/6 Mouse (5-
10 males/group)
Water: 0, 62.5,125, 250 ppm sodium
dichromate dihydrate; equivalent to
0, 2.8, 5.2 or 8.7 mg Cr Vl/kg-d (M)
7 d/wk, 3 mo
Strain Comparison Study
No treatment-related effects were observed for spermatids per testis and
per mg testis, spermatids per cauda and per mg cauda, sperm motility.
NTP (1997)
BALB/c Mouse (20 males/group)
Continuous Breeding Protocol: FO animals
exposed for 13 wks total, 1 wk prior to and
12 wks during cohabitation. After
cohabitation, FO breeding pairs were
separated and continued on study diets.
Diet: 0,100, 200, 400 ppm potassium
dichromate (equivalent to 0,17.6, 35.3,
141.2 ppm Cr VI)
(FO): 0,19.4, 38.6, 85.7 mg potassium
dichromate/kg-d (equivalent to 0, 6.8,
13.6, 30.3 mgCr Vl/kg-d)
(Fl): 0, 22.4, 45.5,104.9 mg potassium
dichromate/kg-d (equivalent to 0, 7.9,
16.1, 37.1 mgCr Vl/kg-d)
No statistically significant effects on FO sperm parameters (vas deferens
sperm motion data, epididymal sperm density, epididymal sperm
morphology, number of spermatids per mg testis, total number of sperm
heads per testis).
No statistically significant effects on Fl sperm parameters (vas deferens
sperm motion data, epididymal sperm density, epididymal sperm
morphology, number of spermatids per mg testis, total number of sperm
heads per testis).
Treatment-related decrease in maternal weights at delivery reported for
some of the litters.3 No treatment-related differences reported in
pregnancy index.
NTP (1996a)
BALB/c Mouse (24 males/group, 5-6
males/group pertimepoint)
Diet: 0,15, 50,100, 400 ppm potassium
dichromate; equivalent to 0,1.1, 3.5, 7.4,
32.5 mg Cr Vl/kg-d
Sacrificed after 3, 6, 9 wks of treatment or
after 8-wk recovery period
No statistically significant effects observed on Sertoli nuclei and preleptotene
spermatocyte counts in Stage X or XI tubules or chromatin structure of
sperm.
Zahidetal. (1990)
BALB/c Mouse (7 males/group)
Diet: 0,100, 200, 400 mg potassium
dichromate/kg diet equivalent to
0, 6.4,12.7, 25.5 mg CrVI/kg-d (calculated)
35 d
mg Cr Vl/kg-d
0
6.4
12.7
25.5
Sperm count
(% change)
-44
-56*
-57*
Abnormal sperm/number sperm
examined (incidence (%))
385/3193(12.1)
165/1242 (13.3)
304/1607 (18.9)*
318/1296 (24.5)*
This document is a draft for review purposes only and does not constitute Agency policy,
3-47 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Yousefetal. (2006)
New Zealand White Rabbit (6
males/group)
Gavage: 0, 5 mg potassium
dichromate/kg-d; equivalent to
0, 3.6 mgCr Vl/kg-d
7 d/wk, 10 wk
Results
Percent change from control by exposure group:
Packed Sperm Total
Seminal sperm concentra- sperm Sperm
mg Cr Vl/kg-d fluid pH volume tion output motility
o
3.6 4.1* -9.9* -18* -26* -4.6*
Total Total
motile functional
sperm per Dead Normal sperm
mg Cr Vl/kg-d ejaculation sperm sperm fraction
o
3.6 -34* 24* -3.5* -37*
Hormone Changes - Oral
Chowdhuryand Mitra (1995)
Charles Foster Rat (10 males/group)
Gavage: 0, 20, 40, 60 mg Cr Vl/kg-d;
administered as sodium dichromate
7 d/wk, 90 d
Yousefetal. (2006)
New Zealand White Rabbit (6
males/group)
Gavage: 0, 5 mg potassium
dichromate/kg-d; equivalent to
0, 3.6 mgCr Vl/kg-d
7 d/wk, 10 wk
Percent change from control by exposure group:
mg Cr Vl/kg-d Serum testosterone
0
20 -31.3*
40 -31.3*
60 -46.9*
Percent change from control by exposure group:
mg Cr Vl/kg-d Serum testosterone
0
3.6 -20.8*
Changes in Reaction Time to Mounting - Oral
Yousefetal. (2006)
New Zealand White Rabbit (6
males/group)
Gavage: 0, 5 mg potassium
dichromate/kg-d; equivalent to
0, 3.6 mgCr Vl/kg-d
7 d/wk, 10 wk
Percent change from control by exposure group:
mg Cr Vl/kg-d Reaction time
0
3.6 110*
*Significantly different from control (p<0.05) as calculated by study authors.
Percent change from control calculated as (Treated - Control) 4- Control x 100.
NTP (1997) maternal body weight at delivery (percent change from control):
Mg Cr Vl/kg-d
0
6.8
13.6
30.3
Litter 1
1
*
5*
Litter 2
1
4
7*
Litter 3
-2
4
5*
Litter 4
-2
2
5
Litter 5
-4
3
4
This document is a draft for review purposes only and does not constitute Agency policy,
3-48 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
100 q
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
10
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Figure 3-11. Exposure-response array of male reproductive effects following inhalation exposure to hexavalent
chromium.
This document is a draft for review purposes only and does not constitute Agency policy,
3-50 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.8. Female Reproductive Effects
2
3
Table 3-7. Evidence pertaining to female reproductive organ effects following
oral exposure to hexavalent chromium
Reference and study design
Results
Ovarian Effects
NTP (1996b)
Sprague-Dawley Rat (48 females/group;
12 females/group/timepoint)
Diet: 0,15, 50,100, 400 ppm potassium
dichromate; equivalent to
0, 0.35, 1.1, 2.5, 9.9 mg Cr Vl/kg-d
Sacrificed after 3, 6, 9 wks of treatment or
after 8-wk recovery period
No statistically significant effects observed upon microscopic examination of
ovaries.
NTP (2007)
F344 Rat (10 females/group)
Water: 0, 62.5,125, 250, 500, 1,000 ppm
sodium dichromate dihydrate; equivalent
to 0,1.7, 3.5, 5.9,11.2, 20.9 mg Cr Vl/kg-d
7 d/wk, 3 mo
No statistically significant effects observed upon microscopic examination of
ovaries.
NTP (1996a)
BALB/c Mouse (48 females/group, 12
females/group/timepoint)
Diet: 0,15, 50,100, 400 ppm potassium
dichromate; equivalent to 0,1.8, 5.6,12.0,
48.4 mg Cr Vl/kg-d
Sacrificed after 3, 6, 9 wks of treatment or
after 8-wk recovery period
No statistically significant effects observed upon microscopic examination of
ovaries.
NTP (1997)
BALB/c Mouse (20 females/group)
Continuous Breeding Protocol: FO animals
exposed for 13 wks total, 1 wk prior to and
12 wks during cohabitation. After
cohabitation, FO breeding pairs were
separated and continued on study diets.
0,100, 200, 400 ppm potassium
dichromate (equivalent to 0,17.6, 35.3,
141.2 ppm Cr VI)
(FO): 0,19.4, 38.6, 85.7 mg potassium
dichromate/kg-d (equivalent to 0, 6.8,
13.6, 30.3 mgCr Vl/kg-d)
Lactating F (FO): 0, 32.8, 69.0,143.1 mg
potassium dichromate/kg-d (equivalent to
0,11.6, 24.4, 50.5 mg Cr Vl/kg-d)
(Fl): 0, 22.4, 45.5,104.9 mg potassium
dichromate/kg-d (equivalent to 0, 7.9,
16.1, 37.1 mgCr Vl/kg-d)
No statistically significant effects on FO or Fl ovarian weight.
Treatment-related decrease in maternal weights at delivery reported for some
of the litters.3 No treatment-related differences reported in pregnancy index.
This document is a draft for review purposes only and does not constitute Agency policy,
3-51 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Murthyetal. (1996)
Swiss Albino Mouse (30 females/group in
the 20-d study; 10 females/group in the
90-d study)
Water: 0, 250, 500, 750 mg Cr VI/L (as
potassium dichromate) in the 20-d study;
equivalent to 0, 64,128,192 mg Cr Vl/kg-d
0, 0.05, 0.5, 5 mg Cr VI/L (as potassium
dichromate) in the 90-d study; equivalent
to 0, 0.0128, 0.128,1.28 mg Cr Vl/kg-d
7 d/wk, 20 or 90 d
Percent change from control by exposure group at 20 d:
Number of Number of Number of Ovarian
mg Cr small
Vl/kg-d follicles
0
64
128
192
-8.1
-13.7*
-36*
large
follicles
-13.2*
-31.6*
-68.4*
medium
follicles
-22.4*
-36.7*
-53.1*
response to Duration of
gonadotropin estrous cycle
-3.1
-29.8*
-90.8*
6.8
31.8
75*
Quantitative data not provided for 90-day study.
Reproductive Performance
NTP (1997)
BALB/c Mouse (20 females/group)
Continuous Breeding Protocol: FO animals
exposed for 13 wks total, 1 wk prior to and
12 wks during cohabitation. After
cohabitation, FO breeding pairs were
separated and continued on study diets.
0,100, 200, 400 ppm potassium
dichromate (equivalent to 0,17.6, 35.3,
141.2 ppm Cr VI)
(FO): 0,19.4, 38.6, 85.7 mg potassium
dichromate/kg-d (equivalent to 0, 6.8,
13.6, 30.3 mgCr Vl/kg-d)
Lactating F (FO): 0, 32.8, 69.0,143.1 mg
potassium dichromate/kg-d (equivalent to
0,11.6, 24.4, 50.5 mg Cr Vl/kg-d)
(Fl): 0, 22.4, 45.5,104.9 mg potassium
dichromate/kg-d (equivalent to 0, 7.9,
16.1, 37.1 mgCr Vl/kg-d)
No significant effects on FO reproductive parameters (average litters per pair,
average live pups per litter, proportion of pups born alive, adjusted live pup
weight, cumulative days to litter).
No significant effects on Fl reproductive parameters (mating index,
pregnancy index, fertility index, live pups per litter, proportion of pups born
alive, adjusted live pup weight, gestation length, estrous cycle length).
Treatment-related decrease in maternal weights at delivery reported for some
of the litters.3 No treatment-related differences reported in pregnancy index.
*Significantly different from control (p<0.05) as calculated by study authors.
Percent change from control calculated as (Treated - Control) -f Control x 100.
a NTP (1997) maternal body weight at delivery (percent change from control):
Mg Cr Vl/kg-d Litter 1 Litter 2 Litter 3 Litter 4 Litter 5
0
6.8 11 -2-2 -4
13.6 5* 4 42 3
30.3 5* 7* 5* 5 4
This document is a draft for review purposes only and does not constitute Agency policy,
3-52 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1000
100
£ io
T3
2
I
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.9. Reproductive and Fetal Outcomes - Dosing Prior to Gestation
2
3
Table 3-8. Evidence pertaining to reproductive/fetal outcomes resulting from
oral dosing prior to gestation
Reference and study design
Results
Implantation Loss, Number of Implants, and Number of Corpora Lutea
Kanoiiaetal. (1998)
Druckrey Rat, Female (10/group)
Water: 0, 70, 127, 170 mg Cr Vl/kg-d
3 mo prior to gestation
Percent change from control by exposure group:
% Pre- % Post-
mg Cr implantation implantation Number of Number of
Vl/kg-d loss loss implantations corpora lutea
o
70 103* 127* -15.4 -8.95
127 176* 281* -30.2* -20.7*
170 214* 323* -42.0* -32.1*
Treatment-related decrease in maternal weight gain reported.3
Resorptions
Kanoiiaetal. (1998)
Druckrey Rat, Female (10/group)
Water: 0, 70, 127, 170 mg Cr Vl/kg-d
3 mo prior to gestation
Percent change from control by exposure group:
mg Cr Vl/kg-d Resorptions
0
70 92
127 166*
170 215*
Treatment-related decrease in maternal weight gain reported.3
Estrous Cycle Length
Kanoiiaetal. (1998)
Druckrey Rat, Female (10/group)
Water: 0, 70, 127, 170 mg Cr Vl/kg-d
3 mo prior to gestation
Percent change from control by exposure group:
Postpartum estrous
mg Cr Vl/kg-d cycle length
0
70 24
127 40*
170 68*
Treatment-related decrease in maternal weight gain reported.3
This document is a draft for review purposes only and does not constitute Agency policy,
3-54 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Number of Live Fetuses
Kanoiiaetal. (1998)
Druckrey Rat, Female (10/group)
Water: 0, 70, 127, 170 mg Cr Vl/kg-d
3 mo prior to gestation
Percent change from control by exposure group:
mg Cr Vl/kg-d Live fetuses per litter
0
70 -22
127 -41*
170 -55*
Treatment-related decrease in maternal weight gain reported.3
Fetal Body Weight and Length
Kanoiiaetal. (1998)
Druckrey Rat, Female (10/group)
Water: 0, 70, 127, 170 mg Cr Vl/kg-d
3 mo prior to gestation
Percent change from control by exposure group:
mg Cr Vl/kg-d Fetal weight Fetal crown-rump
length
0
70 -21* -14
127 -30* -25*
170 -37* -28*
Treatment-related decrease in maternal weight gain reported.3
Fetal Gross External Abnormalities
Kanoiiaetal. (1998)
Druckrey Rat, Female (10/group)
Water: 0, 70, 127, 170 mg Cr Vl/kg-d
3 mo prior to gestation
Percentage of total pups observed with abnormality:
Drooping Subdermal
mg Cr Vl/kg-d wrist hemorrhagic patches Kinky tail
000 0
70 5* 8* 0
127 15* 17* 11*
170 28* 24* 20*
Treatment-related decrease in maternal weight gain reported.3
Short tail
0
0
13*
48*
Fetal Skeletal Abnormalities
Kanoiiaetal. (1998)
Druckrey Rat, Female (10/group)
Water: 0, 70, 127, 170 mg Cr Vl/kg-d
3 mo prior to gestation
Percentage of total pups observed with abnormality:
Reduced
Reduced parietal interparietal Reduced caudal
mg Cr Vl/kg-d ossification ossification ossification
0 0 0 12
70 0 0 25*
127 24* 28* 59*
170 50* 45* 91*
Treatment-related decrease in maternal weight gain reported.3
*Significantly different from control (p<0.05) as calculated by study authors.
Unless otherwise noted, results shown are percent change from control calculated as (Treated - Control) -f Control x 100.
1
2
3
4
'Kanoiiaetal. (1998)
mg Cr Vl/kg-d
0
70
12
170
maternal body weight gain (percent change from
Maternal body weight gain at end of treatment
—
-8
-18*
-24*
control):
This document is a draft for review purposes only and does not constitute Agency policy,
3-55 DRAFT—DO NOT CITE OR QUOTE
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.10. Reproductive and Fetal Outcomes - Dosing During Gestation Only
2
3
Table 3-9. Evidence pertaining to reproductive/fetal outcomes resulting from
oral dosing during gestation only
Reference and study design
Results
Number of Pregnancies
Batainehetal. (2007)
Sprague-Dawley Rat, Female (10/group)
Gavage: 0, 25 mg potassium
dichromate/rat; equivalent to
0, 35 mg Cr Vl/kg-d
GD1-3
mg Cr Vl/kg-d
0
35
Incidence of pregnancy
10/10
0/10*
Maternal toxicity not evaluated.
Batainehetal. (2007)
Sprague-Dawley Rat, Female (10/group)
Gavage: 0, 25 mg potassium
dichromate/rat; equivalent to
0, 35 mg Cr Vl/kg-d
GD4-6
mg Cr Vl/kg-d
0
35
Incidence of pregnancy
9/10
7/10
Maternal toxicity not evaluated.
Implantation Loss, Number of Implants, and Number of Corpora Lutea
Batainehetal. (2007)
Sprague-Dawley Rat, Female (10/group)
Gavage: 0, 25 mg potassium
dichromate/rat; equivalent to
0, 35 mg Cr Vl/kg-d
GD1-3
mg Cr Vl/kg-d
0
35
Number of implants (meaniSD)
8.20±1.68
0*
Maternal toxicity not evaluated.
Batainehetal. (2007)
Sprague-Dawley Rat, Female (10/group)
Gavage: 0, 25 mg potassium
dichromate/rat; equivalent to
0, 35 mg Cr Vl/kg-d
GD4-6
mg Cr Vl/kg-d Number of implants (meaniSD)
0 9.22±2.06
35 7.50±2.97
Maternal toxicity not evaluated.
Elsaieed and Nada (2002)
Wistar Rat, Female (10/group)
Water: 0, 50 ppm Cr VI as potassium
chromate; equivalent to
0, 7.9 mgCr Vl/kg-d
GD 6-15
mg Cr Number of preimplantation Number of postmplantation
Vl/kg-d losses/litter (meaniSE) losses/litter (meaniSE)
00 0
7.9 2.1±0.36* 1.5±0.34*
Treatment-related decrease in maternal weight gain reported.3
Junaidetal. (1996b)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
0, 53,101,152 mg Cr Vl/kg-d
GD 6-14
mg Cr Vl/kg-d % Postimplantation loss (meaniSE)
0 4.32±2.34
53 10.60±2.11
101 21.93±3.96*
152 34.60±2.54*
No statistically significant change in the number of corpora lutea observed.
Treatment-related decrease in maternal weight gain reported.b
This document is a draft for review purposes only and does not constitute Agency policy,
3-56 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Junaidetal. (1995)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
0, 53, 101, 152 mg Cr Vl/kg-d
GD 14-19
Results
me Cr Vl/kg-d
% Postimplantation loss (meaniSE)
0 0
53 3.51±2.30
101 18.80±3.85*
152 27.30±2.82*
No statistically significant change in the number of corpora lutea, resorptions,
or fetuses per litter observed. Treatment-related decrease in maternal
weight gain reported.0
Number of Resorptions
Batainehetal. (2007)
Sprague-Dawley Rat, Female (10/group)
Gavage: 0, 25 mg potassium
dichromate/rat; equivalent to
0, 35 mg Cr Vl/kg-d
GD1-3
Batainehetal. (2007)
Sprague-Dawley Rat, Female (10/group)
Gavage: 0, 25 mg potassium
dichromate/rat; equivalent to
0, 35 mg Cr Vl/kg-d
GD4-6
Elsaieed and Nada (2002)
Wistar Rat, Female (10/group)
Water: 0, 50 ppm Cr VI as potassium
chromate; equivalent to
0, 7.9 mgCr Vl/kg-d
GD 6-15
Junaidetal. (1996b)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
0, 53, 101, 152 mg Cr Vl/kg-d
GD 6-14
mg Cr Vl/kg-d
0
35
Maternal toxicity
mg Cr Vl/kg-d
0
35
Maternal toxicity
mg Cr Vl/kg-d
Number of resorptions/total implantations
0/82
0
not evaluated.
Number of resorptions/total implantations (%)
2/83 (2.4)
41/53 (77.3)*
not evaluated.
Number of resorptions/litter (meaniSE)
0 0
7.9 1.2±0.13*
Treatment-related decrease in maternal weight gain reported.3
mg Cr Vl/kg-d
Number of resorption sites (meaniSE)
0 0.30±0.21
53 1.00±0.21*
101 1.70±0.3*
152 2.30±0.273*
Treatment-related decrease in maternal weight gain reported. b
Fetal Viability
Batainehetal. (2007)
Sprague-Dawley Rat, Female (10/group)
Gavage: 0, 25 mg potassium
dichromate/rat; equivalent to
0, 35 mg Cr Vl/kg-d
GD1-3
mg Cr Vl/kg-d
0
35
Maternal toxicity
Number of viable fetuses/female (meaniSD)
8.20±1.68
0*
not evaluated.
This document is a draft for review purposes only and does not constitute Agency policy,
3-57 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Batainehetal. (2007)
Sprague-Dawley Rat, Female (10/group)
Gavage: 0, 25 mg potassium
dichromate/rat; equivalent to
0, 35 mg Cr Vl/kg-d
GD4-6
Elsaieed and Nada (2002)
Wistar Rat, Female (10/group)
Water: 0, 50 ppm Cr VI as potassium
chromate; equivalent to
0, 7.9 mgCr Vl/kg-d
GD 6-15
Junaidetal. (1996b)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
0, 53, 101, 152 mg Cr Vl/kg-d
GD 6-14
Junaidetal. (1995)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
0, 53, 101, 152 mg Cr Vl/kg-d
GD 14-19
Fetal Body Weight and Length
Elsaieed and Nada (2002)
Wistar Rat, Female (10/group)
Water: 0, 50 ppm Cr VI as potassium
chromate; equivalent to
0, 7.9 mgCr Vl/kg-d
GD 6-15
Junaidetal. (1996b)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
0, 53, 101, 152 mg Cr Vl/kg-d
GD 6-14
Results
mg Cr Vl/kg-d Number of viable fetuses/female (meaniSD)
0 9.04i2.14
35 2.80i0.83*
Maternal toxicity not evaluated.
Number of live Number of dead
mg Cr Vl/kg-d fetuses/litter (meaniSE) fetuses/litter (meaniSE)
0 6.8i0.44 O.liO.099
7.9 1.5i0.29* 1.2i0.24*
Treatment-related decrease in maternal weight gain reported.3
mg Cr Vl/kg-d Number of live and dead fetuses (meaniSE)
0 8.8i0.29
53 8.20i0.20
101 7.00i0.36*
152 7.20i0.24*
Treatment-related decrease in maternal weight gain reported. b
No statistically significant change in the number of fetuses per litter or the
number of dead fetuses (number of litters) observed. Treatment-related
decrease in maternal weight gain reported.0
Percent change from control by exposure group:
mg Cr Vl/kg-d Fetal weight
0
7.9 -33*
Treatment-related decrease in maternal weight gain reported.3
Percent change from control by exposure group:
mg Cr Vl/kg-d Fetal weight
0
53 -3
101 -13*
152 -19*
Treatment-related decrease in maternal weight gain reported. b
This document is a draft for review purposes only and does not constitute Agency policy,
3-58 DRAFT—DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Junaidetal. (1995)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
0, 53, 101, 152 mg Cr Vl/kg-d
GD 14-19
Fetal Gross External Abnormalities
Elsaieed and Nada (2002)
Wistar Rat, Female (10/group)
Water: 0, 50 ppm Cr VI as potassium
chromate; equivalent to
0, 7.9 mgCr Vl/kg-d
GD 6-15
Junaidetal. (1996b)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
, 53, 101, 152 mg Cr Vl/kg-d
GD 6-14
Junaidetal. (1995)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
, 53, 101, 152 mg Cr Vl/kg-d
GD 14-19
Results
Percent change from control by exposure group:
mg Cr Vl/kg-d Fetal weight Fetal crown-rump length
0
53 -18* -4*
101 -37* -15*
152 -47* -29*
Treatment-related decrease in maternal weight gain reported.0
mg Cr Vl/kg-d Visceral anomalies/litter (meaniSE)
0 0
7.9 2.1±0.39*
Treatment-related decrease in maternal weight gain reported.3
Percentage of total pups observed with abnormality :
Subdermal
mgCrVI/kg- Drooping hemorrhagic
d wrist patches Kinky tail Short tail
000 00
53 8 0 00
101 10 10 7 12
152 16* 16* 12 8
Treatment-related decrease in maternal weight gain reported. b
Percentage of total pups observed with abnormality:
Subdermal
mgCrVI/kg- Drooping hemorrhagic
d wrist patches Kinky tail Short tail
000 00
53 5 0 80
101 13* 8 80
152 19* 19* 15* 23*
Treatment-related decrease in maternal weight gain reported.0
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Fetal Skeletal Abnormalities
Elsaieed and Nada (2002)
Wistar Rat, Female (10/group)
Water: 0, 50 ppm Cr VI as potassium
chromate; equivalent to
0, 7.9mgCrVI/kg-d
GD 6-15
Junaidetal. (1996b)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
0, 53, 101, 152 mg Cr Vl/kg-d
GD 6-14
mg Cr Vl/kg-d Skeletal anomalies/litter (meaniSE)
0 0
7.9 1.0±0.34*
Treatment-related decrease in
Percentage of total pups obser
mg Cr Vl/kg- Reduced nasal
d ossification
0 0
53 0
101 0
152 32*
Reduced
mg Cr Vl/kg- interparietal
d ossification
0 0
53 0
101 0
152 40*
Treatment-related decrease in
maternal weight gain reported.3
ved with abnormality:
Reduced frontal Reduced parietal
ossification ossification
0 0
0 0
0 0
40* 32*
Reduced caudal Reduced tarsals
ossification ossification
3 0
8 0
47* 0
84* 76*
maternal weight gain reported. b
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Junaidetal. (1995)
Swiss Albino Mouse, Female (10/group)
Water: 0, 250, 500, 750 ppm Cr VI as
potassium dichromate; equivalent to
0, 53, 101, 152 mg Cr Vl/kg-d
GD 14-19
Results
Percentage of total pups ob<
Reduced
mgCrVI/kg- nasal
d ossification
0 0
53 0
101 0
152 31*
Reduced
mgCrVI/kg- carpal
d ossification
0 0
53 0
101 0
152 50*
Treatment-related decrease
>erved with abnormality:
Reduced Reduced
parietal interparietal Reduced caudal
ossification ossification ossification
005
0 0 38*
0 0 67*
35* 76* 80*
Reduced Reduced
metacarpal tarsal
ossification ossification
0 0
0 0
0 67*
80* 84*
in maternal weight gain reported.0
*Significantly different from control (p<0.05) as calculated by study authors.
Percent change from control calculated as (Treated - Control) 4- Control x 100.
GD = gestation day
1
2
3
4
5
6
a Elsaieed and Nada (2002)maternal body weight gain (percent change
mg Cr Vl/kg-d
0
7.9
b Junaidetal. (1996b)
mg Cr Vl/kg-d
Maternal gestational weigh gain
i from control)
-40*
maternal body weight gain (percent change from control):
Maternal gestational weight gain
0
53 -2
101 -8*
152 -24*
c Junaid et al. (1995) maternal body weight gain (percent change from
mg Cr Vl/kg-d Maternal gestational weight gain
0
53
101
152
0
-11*
-26*
control):
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.11. Offspring Outcomes - Dosing During Gestation and Lactation or
2 Lactation Only
3 Table 3-10. Evidence pertaining to offspring outcomes resulting from oral
4 dosing during gestation and lactation or lactation only3
Reference and study design
Results
EXPOSURE DURING GESTATION AND LACTATION
Offspring Parameters
Soudanietal. (2011b)
Wistar Rat (6 FO dams/group)
Water: 0, 700 ppm potassium dichromate;
equivalent to 62.4 mg Cr Vl/kg-d
GD 14-PND 14
Offspring sacrificed on PND 14
Percent change from control by exposure group:
Pup final Pup femur
mg Cr Vl/kg-d body weight weight
0
62.4 -25* -24*
Statistically significant decrease in food consumption and water
consumption in dosed dams relative to control.0 Maternal weight not
reported in this study.
Pup femur
length
-17"
Soudani etal. (2011c)
Wistar Rat (6 FO dams/group)
Water: 0, 700 ppm potassium dichromate;
equivalent to 62.4 mg Cr Vl/kg-d
GD 14-PND 14
Offspring sacrificed on PND 14
Percent change from control by exposure group:
mg Cr Vl/kg-d Pup relative kidney weight
0
62.4 -12*
Statistically significant decrease in maternal weight, food consumption, and
water consumption in dosed dams relative to control.0
Soudanietal. (2013)
Wistar Rat (6 FO dams /group)
Water: 0, 700 ppm potassium dichromate;
equivalent to 62.4 mg Cr Vl/kg-db
GD 14-PND 14
Offspring sacrificed on PND 14
Percent change from control by exposure group in pups:
Relative liver
mg Cr Vl/kg-d Final body weight weight
0
62.4 -26* -14*
For serum data, n = 8 pups/group
mg Cr Vl/kg-d ALT AST
0
62.4 41* 72*
Qualitative histopathology of liver sections of the pups indicated severe
infiltration of mononuclear cells, parenchyma dilatation, and moderate
vacuolization, but no hemorrhage or necrosis.
Statistically significant decrease in maternal weight, food consumption, and
water consumption in dosed dams relative to control; histopathological
lesions of the liver; elevated ALT, AST, and bilirubin relative to controls.0
Bilirubin
31*
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
EXPOSURE DURING LACTATION ONLY
Number of Follicles in Female Offspring
Banuetal. (2008)
Wistar Rat (18 dams/group; 4 female
pups/dam)
Water: 0, 200 ppm potassium dichromate;
equivalent to 0, 70.6 ppm Cr Vld
Dams exposed postpartum days 1-21
Offspring evaluated on PND 21, 45, 65
Percent change from control by exposure group:
PND21
Primordial Primary Secondary
ppmCrVI follicles follicles follicles
o
70.6 -25* -338* -36*
PND 45
Primordial Primary Secondary
ppmCrVI follicles follicles follicles
o
70.6 -31* -35* -48*
PND 65
Primordial Primary Secondary
ppmCrVI follicles follicles follicles
Antral
follicles
-100*
Antral
follicles
-85*
Antral
follicles
o
70.6 -19* -33* -7 -7
Study did not report whether maternal toxicity was evaluated.
Sexual Maturation in Female Offspring
Banuetal. (2008)
Wistar Rat (18 dams/group; 4 female
pups/dam)
Water: 0, 200 ppm potassium dichromate;
equivalent to
0,70.6 ppm CrVld
Dams exposed postpartum days 1-21
Offspring evaluated on PND 21, 45, 65
ppmCrVI Onset of puberty Duration of diestrous
0
70.6 -25* -338*
Cr VI exposure did not change the length of proestrous, estrous, or
metestrous phases of the estrous cycle. Study did not report whether
maternal toxicity was evaluated.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Hormone Changes in Female Offspring
Banuetal. (2008)
Wistar Rat (18 dams/group; 4 female
pups/dam)
Water: 0, 200 ppm potassium dichromate;
equivalent to 0, 70.6 ppm Cr Vld
Dams exposed postpartum days 1-21
Offspring evaluated on PND 21, 45, 65
Percent chang
PND21
ppm Cr VI
0
70.6
PND 45
ppm CrVI
0
70.6
PND 65
ppm CrVI
0
70.6
Study did not
;e from
E2
-63*
E2
—
-45*
E2
—
-33.2
control by
T
-60*
T
—
-51*
T
—
* -48*
exposure group:
P4 LH
-55* 15
P4 LH
„
-42* 11
P4 LH
„
-42* 15
FSH
60*
FSH
—
67*
FSH
—
8.6
GH
-52*
GH
—
-47*
GH
—
-29*
PRL
-36*
PRL
—
-42*
PRL
—
-48*
report whether maternal toxicity was evaluated.
1
2
3
4
5
6
7
8
9
10
11
12
13
*Significantly different from control (p<0.05) as calculated by study authors.
Percent change from control calculated as (Treated - Control) 4- Control x 100.
aNo exposure-response array was prepared for these results because only single-dose studies were available.
bTo estimate mg/kg-d, a body weight value of 0.15kg was assumed based on review of similar studies (Soudani et
al., 2011a) in adult female Wistar rats by the same investigators.
cSoudani et al. (2013); Soudani et al. (2011b); Soudani et al. (2011c) maternal weight change, maternal food intake,
and maternal water consumption (percent change from control), ALT, AST, bilirubin.
mg Cr Vl/kg-d Maternal Body Maternal Food Maternal Water ALT AST Bilirubin
Weight Intake Consumption
0
62.4 -4 -9 -8 +83 +69 +79
dDoses in mg/kg-d were not estimated from this drinking water study because study authors had reported
decreased body weight but body weights were not reported.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1000
• Statistically Significant o Not Statistically Significant
100
(D
TJ
I
o
Q
10
o 2?
—
£ "re
raS
— ffl
^) ^H
Reproductive Outcomes
.
-S.2
Growth
•— ™
•— ^
a; o
=
reduced
ossification
Fetal Outcomes
ingwrist,
el al., 19
Dro
noj
Kinky/short tai
ojia etal., 1998
gross
abnormalities
2 Figure 3-13. Exposure-response array of reproductive and fetal outcomes (dosing prior to gestation) following oral exposure to
3 hexavalent chromium. [SHP]: subdermal hemorrhagic patches.
This document is a draft for review purposes only and does not constitute Agency policy,
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DRAFT— DO NOT CITE OR QUOTE
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1000 :
100 :
"^ 1 n -
^ ±\j
TJ
tio ;
3
Q
• Statistically Significant O Not Statistically Significant
• • • "I • ! * • • * •••O*
II ii 4 1 1 i i 1 o >
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t t I T
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m VD
Q Q
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rvl rM
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jz .c
0> 0)
c c
'ro 'ro
CO 03
pregnancies
m tf> ^ -^j-
'(52 S
^ m c
implantation
loss
•^ ^t •"• on ID
^ Q — Q ^>
| 1 i I 1
! 1 i i §
"S 1 I -s ra
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resorptions
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c c c
're = =
re
to
viability
Reproductive Outcomes
•^r en Tt
- — ' —
— 4 10
Elsaieed & Nada, 2002
tal., 1995 (mice) GDI
tal., 1996b(mice)GD
g s a
ab 03 'S
ij- ^
ti m>
1 3
08
§
1
growth
32^
" 3 —
Q rxj
» § §
i ! i
1 s -
» a. 1
»r » a
"O -
-s g 5
c ^ a,
= 5-2
I
1 1
>
abnormalfties
33222
*& *D Tf ^ «fr
Q Q " " "
in tn Q Q Q
O (D ID
^ *S *3T 'oT 'oT
-— •— o o u
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S a! ^ ^ ^
1 1 1 1 1
|" £ 1 Is .1
= 'S ra S «
ra u 1- 5
O
-------
Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 3.12. Carcinogenic Effects
2
3
Table 3-11. Evidence pertaining to carcinogenic effects following oral or
inhalation exposure to hexavalent chromium
Reference and study design
Results
Oral Mucosa Tumors - Oral
NTP (2008)
F344 Rat (50/sex/group)
Water: 0, 14.3, 57.3, 172, 516 ppm sodium
dichromate dihydrate; equivalent to
0, 0.21, 0.77, 2.1, 5.9 mg Cr Vl/kg-d (M)
0, 0.24, 0.94, 2.4, 7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
Incidence (percent) by exposure group:
Males
mg Cr Vl/kg-d
0
0.21
0.77
2.1
5.9
Females
mg Cr Vl/kg-d
0
0.24
0.94
2.4
7
Oral mucosa:
squamous cell carcinoma
0/50 (0)
0/50 (0)
0/49 (0)
0/50 (0)
6/49 (12.2)*
Oral mucosa:
squamous cell carcinoma
0/50 (0)
0/50 (0)
0/50 (0)
2/50 (4)
11/50 (22)*
Oral mucosa or tongue:
Squamous cell
papilloma or carcinoma
0/50 (0)
1/50 (2)
0/49 (0)
0/50 (0)
7/49 (14.3)*
Oral mucosa or tongue:
Squamous cell
papilloma or carcinoma
1/50 (2)
1/50 (2)
0/50 (0)
2/50 (4)
11/50 (22)*
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Digestive System Tumors - Oral
NTP (2008)
B6C3F1 Mouse (50/sex/group)
\A/n + nvi /~\ *l >l O TO C OC ~7 1C~7 A n n nn
Water: 0, 14.3, 28.6, 85.7, 257 A ppm
sodium dichromate dihydrate (M)
0, 14.3, 57.3, 172, 516 ppm sodium
dichromate dihydrate (F), equivalent to
0, 0.38, 0.91, 2.4, 5.9 mg Cr Vl/kg-d (M)
0, 0.38, 1.4, 3.1, 8.7 mg Cr Vl/kg-d (F)
7 d/wk, 104 wk
Related reference: Stout et al. (2009)
Incidence (percent) by exposure group:
Males
me Cr Vl/kg-d
0
0.38
0.91
2.4
5.9
Females
mg Cr Vl/kg-d
0
0.38
1.4
3.1
8.7
mg Cr Vl/kg-d
0
0.38
1.4
3.1
8.7
Small
intestine,
duodenum:
adenoma
1/50 (2)
0/50 (0)
1/50 (2)
5/50 (10)
15/50 (30)*
Small
intestine,
duodenum:
adenoma
0/50 (0)
0/50 (0)
2/50 (4)
13/50 (26)*
12/50 (24)*
Small
intestine,
duodenum,
jejunum,
ileum:
carcinoma
1/50 (2)
0/50 (0)
2/50 (4)
3/50 (6)
7/50 (14)*
Small
intestine,
duodenum,
jejunum,
ileum:
adenoma
1/50 (2)
1/50 (2)
1/50 (2)
5/50 (10)
17/50 (34)*
Small
intestine,
duodenum:
carcinoma
0/50 (0)
0/50 (0)
0/50 (0)
1/50 (2)
6/50 (12)*
Small
intestine,
duodenum,
jejunum,
ileum:
adenoma or
carcinoma
1/50 (2)
1/50 (2)
4/50 (8)
17/50 (34)*
22/50 (44)*
Small
intestine,
duodenum,
jejunum,
ileum:
carcinoma
0/50 (0)
2/50 (4)
1/50 (2)
3/50 (6)
5/50 (10)*
Small
intestine,
jejunum:
adenoma
0/50 (0)
1/50 (2)
0/50 (0)
2/50 (4)
5/50 (10)*
Small
intestine,
duodenum,
jejunum,
ileum:
adenoma or
carcinoma
1/50 (2)
3/50 (6)
2/50 (4)
7/50 (14)*
20/50 (40)*
Small
intestine,
duodenum,
jejunum,
ileum:
adenoma
0/50 (0)
1/50 (2)
2/50 (4)
15/50 (30)*
16/50 (32)*
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Pharyngeal Tumors - Inhalation
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.025, 0.05, 0.1 mg Cr VI /m3 as sodium
dichromate (dynamic whole-body
chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and
cyclone), analytical method (photometric,
by diphenylcarbazine complexation),
analytical concentration, and MMD
reported.
Incidence (percent) by exposure group:
mg/m3 Squamous cell carcinoma
0 0/37 (0)
0.025 0/18 (0)
0.05 0/18 (0)
0.1 1/19 (5)
Lung Tumors - Inhalation
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.025, 0.05, 0.1 mg Cr VI /m3 as sodium
dichromate (dynamic whole-body
chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and
cyclone), analytical method (photometric,
by diphenylcarbazine complexation),
analytical concentration, and MMD
reported.
Incidence (percent) by exposure group:
Adenocarcinoma
0/37 (0)
0/18 (0)
0/18 (0)
1/19 (5)
Adenoma
0/37 (0)
0/18 (0)
0/18 (0)
2/19 (11)
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.063 mg Cr Vl/m3 as pyrolized mixture
of 3:2 Cr VI/Cr(lll) oxide (dynamic whole-
body chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and
cyclone), analytical method (photometric,
by diphenylcarbazine complexation),
analytical concentration, and MMD
reported.
Incidence (percent) by exposure group:
mg/m3 Adenoma
0 0/37 (0)
0.063 1/18 (5.6)
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
Reference and study design
Results
Nettesheim et al. (1971)
C57BL/6 Mouse (136 males/136 females)
0,13 mg/m3 of calcium chromate dust
(equivalent to 4.33 mg Cr Vl/m3) (dynamic
whole-body chamber)
5 hr/d, 5 d/wk
lifespan (~2 yr)
Generation method (Wright dust feed),
analytical method (gravimetric filter),
analytical concentration reported; MMAD
not reported.
Methods: Nettesheim et al. (1970)
% incidence of lung tumors by exposure group:
Males Females
3/136 (2.2) 2/137 max (1.5)
6/136 (4.4) 2/137 max (1.5)
Authors state that 15 mice per chamber underwent histopathological
examination at 6,12, and 18 months. It is unclear how many mice per
exposure group were examined at these points. It is unclear whether these
mice are included in the data presented for lung tumor incidence or if
incidence was for the remaining animals that underwent examination at the
end of the study only (data presented is number with tumors but it does not
say what total number is). It is also unclear whether the female groups
contained 136 or 137 total mice (authors report 273 per chamber, % treated
with irradiation and % not). Results for lung tumors were only pathological
data reported. Authors provide qualitative statements for epithelial changes
in the bronchial tree, bronchiolization of alveoli and alveolar lesions, and
morphological changes in tracheal and submandibular lymph nodes, but do
not provide data and do not specify results for non-irradiated, non-flu
infected mice.
Other Tumors - Inhalation
Glaseretal. (1986)
Wistar Rat, Male (40/control, 20/treatment
group)
0, 0.063 mg Cr Vl/m3 as pyrolized mixture
of 3:2 Cr Vl/Cr III oxide (Cr5O12) (dynamic
whole-body chamber)
22 hr/d, 7 d/wk
72 wk
Generation method (jet nebulizer and
cyclone), analytical method (photometric,
by diphenylcarbazine complexation),
analytical concentration, and MMD
reported.
Authors state that all of the following observed tumor locations "gave no
indication of a carcinogenicity of the chromium compound": pituitary gland,
pancreas, liver, spleen, parathyroid, adrenal glands, bladder, testes, kidney,
gastrointestinal tract, heart or muscle, skin and appendices.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1
2 REFERENCES
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5 8329(00)00139-7
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7 female mice exposed prenatally and postnatally to trivalent and hexavalent chromium
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13 Akbarsha. MA. (2005). Chronic chromium exposure-induced changes in testicular
14 histoarchitecture are associated with oxidative stress: study in a non-human primate
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17 Aruldhas. MM: Subramanian. S: Sekhar. P: Hasan. GC: Govindaraiulu. P: Akbarsha. MA. (2004).
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19 exposure to chromium - a study in the mature bonnet monkey (Macaca radiata Geoffrey).
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21 Aruldhas, MM: Subramanian, S: Sekhar, P: Vengatesh, G: Govindarajulu, P: Akbarsha, MA. (2006). In
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23 cells, basal cells, and intraepithelial macrophages of a nonhuman primate (Macaca radiata
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25 Asmatullah: Noreen. MA. (1999). Effectof oral administration of hexavalent chromium on total
26 body weight, chromium uptake and histological structure of mouse liver. Punjab Univ J Zool
27 14:53-63.
28 ATSDR (Agency for Toxic Substances and Disease Registry). (2012). Toxicological profile for
29 chromium. Atlanta, GA: US Department of Health and Human Services, Public Health
30 Service, http://www.atsdr.cdc.gov/toxprofiles/tp7.pdf
31 Banu. SK: Samuel. IB: Arosh. TA: Burghardt. RC: Aruldhas. MM. (2008). Lactational exposure to
32 hexavalent chromium delays puberty by impairing ovarian development, steroidogenesis
33 and pituitary hormone synthesis in developing Wistar rats. Toxicol Appl Pharmacol 232:
34 180-189. http://dx.doi.0rg/10.1016/i.taap.2008.06.002
35 Bataineh. H: Al-Hamood. MH: Elbetieha. A: Bani Hani. I. (1997). Effectof long-term ingestion of
36 chromium compounds on aggression, sex behavior and fertility in adult male rat. Drug
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38 Bataineh, HN: Bataineh, ZM: Daradka, H. (2007). Short-term exposure of female rats to industrial
39 metal salts: Effect on implantation and pregnancy. Reproductive Medicine and Biology 6:
40 179-183. http://dx.doi.0rg/10.llll/i.1447-0578.2007.00183.x
41 Behari, I: Chandra, SV: Tandon, SK. (1978). Comparative toxicity of trivalent and hexavalent
42 chromium to rabbits III Biochemical and histological changes in testicular tissue. Biomed
43 Biochim Acta 37: 463-468.
44 Borneff, 1: Engelhardt, K: Griem, W: Kunte, H: Reichert, I. (1968). Carcinogenic substances in water
45 and soil. XXII. Mouse drinking study with 3,4-benzpyrene and potassium chromate.
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 [Kanzerogene substanzen in wasser und boden. XXII. Mausentrankversuch mit 3,4-
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13 to ozone on the carcinogenic potential of inhaled chromium. 1. Effects on retention and on
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24 hexavalent chromium compounds: effect on fertility. Toxicology 116: 39-47.
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27 role of ginseng. Bull Environ Contam Toxicol 68: 361-368.
28 FDA. US. (2013). Beverages: Bottle water. Code of Federal Regulations: 21 CFR 165.110.
29 http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm
30 Federal Register. (2010). March 29 2010 National Primary Drinking Water Regulations
31 Announcement of the Results of EPA's Review of Existing Drinking Water Standards and
32 Request for Public Comment and/or Information on Related Issues Notice. (815Z10001).
33 http://nepis.epa. gov/exe/ZyPURL.cgi?Dockey=P1007TNX.txt
34 Frey, M: Seidel, C: Edwards, M. (2004). Occurrence survey of boron and hexavalent chromium. (No.
35 91044F). Denver, CO: American Water Works Association Research Foundation.
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38 antioxidant activity of leaf extract of Seabuckthorn (Hippophae rhamnoides L.) on
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48 http://dx.doi.org/10.1016/0300-483Xf86190011-9
This document is a draft for review purposes only and does not constitute Agency policy.
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1 Glaser, U: Hochrainer, D: Oldiges, H. (1988). Investigations of the lung carcinogenic potentials of
2 sodium dichromate and Cr VI/III oxide aerosols in Wistar rats. In NH Seemayer; W Hadnagy
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4 Glaser, U: Hochrainer, D: Steinhoff, D. (1990). Investigation of irritating properties of inhaled Cr(VI)
5 with possible influence on its carcinogenic action. In NH Seemayer; W Hadnagy (Eds.), (pp.
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8 children after playing in playgrounds built from chromated copper arsenate (CCA)-treated
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11 National Library of Medicine. http://toxnetnlm.nih.gov/cgi-bin/sis/htmlgen7HSDB
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13 Arsenic, metals, fibres, and dusts [IARC Monograph]. Lyon, France.
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16 boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium,
17 and zinc. Washington, DC: The National Academies Press.
18 http://www.nap.edu/catalog.php7record id=10026
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20 (78). Geneva, Switzerland: World Health Organization.
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22 Tohansson. A: Robertson. B: Curstedt. T: Camner. P. (1986a). Rabbit lung after inhalation of hexa-
23 andtrivalentchromium. EnvironRes 41: 110-119.
24 Tohansson, A: Wiernik, A: Tarstrand, C: Camner, P. (1986b). Rabbit alveolar macrophages after
25 inhalation of hexa- and trivalent chromium. Environ Res 39: 372-385.
26 http://dx.doi.org/10.1016/S0013-9351f86j80063-9
27 Tunaid, M: Murthy, RC: Saxena, DK. (1995). Chromium fetotoxicity in mice during late pregnancy.
28 Vet Hum Toxicol 37: 320-323.
29 Tunaid. M: Murthy. RC: Saxena. DK. (1996a). Embryo and fetotoxicity of chromium in
30 pregestationally exposed mice. Bull Environ Contain Toxicol 57: 327-334.
31 Tunaid, M: Murthy, RC: Saxena, DK. (1996b). Embryotoxicity of orally administered chromium in
32 mice: exposure during the period of organogenesis. Toxicol Lett 84: 143-148.
33 Kanojia. RK: Tunaid. M: Murthy. RC. (1996). Chromium induced teratogenicity in female rat. Toxicol
34 Lett 89: 207-213.
35 Kanojia, RK: Tunaid, M: Murthy, RC. (1998). Embryo and fetotoxicity of hexavalent chromium: a
36 long-term study. Toxicol Lett 95: 165-172.
37 Kim, HY: Lee, SB: Tang, BS. (2004). Subchronic inhalation toxicity of soluble hexavalent chromium
38 trioxide in rats. Arch Toxicol 78: 363-368. http://dx.doi.org/10.1007/s00204-004-0553-4
39 Krim, M: Messaadia, A: Maidi, I: Aouacheri, 0: Saka, S. (2013). Protective effect of ginger against
40 toxicity induced by chromate in rats. Ann Biol Clin (Paris) 71: 165-173.
41 http://dx.doi.org/10.1684/abc.2013.0806
42 Kumar, A: Barthwal, R. (1991). Hexavalent chromium effects on hematological indices in rats. Bull
43 Environ Contain Toxicol 46: 761-768. http://dx.doi.org/10.1007/BF01689965
44 Li. H: Chen. 0: Li. S: Yao. W: Li. L: Shi. X: Wang. L: Castranova. V: Vallyathan. V: Ernst. E: Chen. C.
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48 effects on lung function. Arch Environ Occup Health 38: 367-374.
This document is a draft for review purposes only and does not constitute Agency policy.
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1 MacKenzie. RD: Byerrum. RU: Decker. CF: Hoppert. CA: Langham. RF. (1958). Chronic toxicity
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8 October; Toronto, ON, Canada. Consideration of chromium as an industrial carcinogen (v. Ill
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10 Mancuso. TF. (1997). Chromium as an industrial carcinogen: Part I. Am J Ind Med 31: 129-139.
11 Mcneill. L: Mclean. I: Edwards. M: Parks. I. (2012). State of the science of Hexavalent Chromium in
12 drinking water. Denver, CO: Water Research Foundation.
13 http://www.waterrf.Org/resources/lists/publicprojectpapers/attachments/2/4404 projec
14 tpaper.pdf
15 Meenakshi, CE: Padmini, E: Motlag, DB. (1989). Comparative toxicity of trivalent and hexavalent
16 chromium in rats. Indian] Environ Health 31: 250-256.
17 Murthy. RC: Tunaid. M: Saxena. DK. (1996). Ovarian dysfunction in mice following chromium (VI)
18 exposure. Toxicol Lett 89: 147-154. http://dx.doi.org/10.1016/S0378-4274r96103803-9
19 Nettesheim. P: Hanna. MG. Tr: Doherty. DG: Newell. RF: Hellman. A. (1971). Effect of calcium
20 chromate dust, influenza virus, and 100 R whole-body X radiation on lung tumor incidence
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26 NIOSH (National Institute for Occupational Safety and Health). (2013). Occupational exposure to
27 hexavalent chromium. (DHHS (NIOSH) Publication No. 2013-128). Department of Health
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31 based soil remediation criterion for Cr+6 based on the NTP chronic bioassay data for
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33 derivation.pdf
34 NRC (National Research Council). (2009). Science and decisions: Advancing risk assessment
35 Washington, DC: National Academies Press, http://www.nap.edu/catalog/12209.html
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42 Service.
43 NTP (National Toxicology Program). (1996b). Final report on the reproductive toxicity of
44 potassium dichromate (hexavalent) (CAS No. 7778-50-9) administered in diet to SD rats
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47 NTP (National Toxicology Program). (1997). Final report on the reproductive toxicity of potassium
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49 Triangle Park: National Institute of Environmental Health Sciences, National Toxicology
50 Program.
This document is a draft for review purposes only and does not constitute Agency policy.
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1 NTP (National Toxicology Program). (2007). NTP technical report on the toxicity studies of sodium
2 dichromate dihydrate (CAS No. 7789-12-0) administered in drinking water to male and
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5 NTP (National Toxicology Program). (2008). Toxicology and carcinogenesis studies of sodium
6 dichromate dihydrate (Gas No. 7789-12-0) in F344/N rats and B6C3F1 mice (drinking
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9 Research Triangle Park, NC. http://ntp.niehs.nih.gov/ntp/roc/twelfth/rocl2.pdf
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11 chromium. Final rule. Fed Reg 71: 10099-10385.
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14 induced by ingestion of water contaminated with high levels of Cr(VI). Toxicol Appl
15 Pharmacol 224: 163-173. http://dx.doi.Org/10.1016/i.taap.2007.07.004
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18 report 711701 025). Bilthoven, the Netherlands: Rijksinstituutvoor Volksgezondheid en
19 Milieu RIVM. http://www.rivm.nl/bibliotheek/rapporten/711701025.html
20 Samuel. IB: Stanley. TA: Roopha. DP: Vengatesh. G: Anbalagan. I: Banu. SK: Aruldhas. MM. (2011).
21 Lactational hexavalent chromium exposure-induced oxidative stress in rat uterus is
22 associated with delayed puberty and impaired gonadotropin levels. Hum Exp Toxicol 30:
23 91-101. http://dx.doi.org/10.1177/0960327110364638
24 Schroeder, HA: Mitchener, M. (1971). Scandium, chromium(VI), gallium, yttrium, rhodium,
25 palladium, indium in mice: effects on growth and life span. J Nutr 101: 1431-1437.
26 Seidel, C: Corwin, C: Khera, R. (2012). Total chromium and hexavalent chromium occurrence
27 analysis. (Web Report #4414). Denver, CO: Water Research Foundation.
28 http://www.waterrf.org/PublicReportLibrary/4414.pdf
29 Shrivastava. R: Srivastava. S: Upreti. RK: Chaturvedi. UC. (2005). Effects of dengue virus infection on
30 peripheral blood cells of mice exposed to hexavalent chromium with drinking water. Indian
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32 Soudani. N: Ben Amara. I: Sefi. M: Boudawara. T: Zeghal. N. (2011a). Effects of selenium on
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34 http://dx.doi.0rg/10.1016/i.etp.2010.04.005
35 Soudani, N: Bouaziz, H: Sefi, M: Chtourou, Y: Boudawara, T: Zeghal, N. (2013). Toxic effects of
36 chromium (VI) by maternal ingestion on liver function of female rats and their suckling
37 pups. Environ Toxicol 28:11-20. http://dx.doi.org/10.1002/tox.20692
38 Soudani. N: Ibtissem Ben Amara. N: Troudi. A: Bouaziz. H: Boudawara. T: Zeghal. N. (2011b).
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40 724-734. http://dx.doi.org/10.1177/0748233710395992
41 Soudani. N: Sefi. M: Bouaziz. H: Chtourou. Y: Boudawara. T: Zeghal. N. (201 Ic). Nephrotoxicity
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44 Stearns. DM. (2000). Is chromium a trace essential metal? [Review]. BioFactors 11: 149-162.
45 Stout. MD: Herbert. RA: Kissling. GE: Collins. BT: Travlos. GS: Witt. KL: Melnick. RL: Abdo. KM:
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47 B6C3F1 mice after chronic oral exposure. Environ Health Perspect 117: 716-722.
48 http://dx.doi.org/10.1289/ehp.0800208
49 Subramanian, S: Rajendiran, G: Sekhar, P: Gowri, C: Govindarajulu, P: Aruldhas, MM. (2006).
50 Reproductive toxicity of chromium in adult bonnet monkeys (Macaca radiata Geoffrey).
This document is a draft for review purposes only and does not constitute Agency policy.
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Preliminary Materials for the IRIS Toxicological Review ofHexavalent Chromium
1 Reversible oxidative stress in the semen. Toxicol Appl Pharmacol 215: 237-249.
2 http://dx.doi.0rg/10.1016/i.taap.2006.03.004
3 Thompson. CM: Proctor. DM: Haws. LC: Hebert. CD: Grimes. SD: Shertzer. HG: Kopec. AK: Hixon. TG:
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5 tumorigenic response induced in B6C3F1 mice exposed orally to hexavalent chromium.
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7 Thompson. CM: Proctor. DM: Suh. M: Haws. LC: Hebert. CD: Mann. IF: Shertzer. HG: Hixon. TG:
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9 canal of F344 rats and B6C3F1 mice following exposure in drinking water: implications for
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11 http://dx.doi.org/10.1093/toxsci/kfr280
12 Trivedi, B: Saxena, DK: Murthy, RC: Chandra, SV. (1989). Embryotoxicity and fetotoxicity of orally
13 administered hexavalent chromium in mice. Reprod Toxicol 3: 275-278.
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22 03/003F). Washington, DC: U.S. Environmental Protection Agency, Risk Assessment Forum.
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24 U.S. EPA (U.S. Environmental Protection Agency). (2008a). Cr (VI) quantitative risk assessment Q*l
25 based on mouse carcinogenicity studies. Washington, DC: Health Effects Division, Office of
26 Pesticide Programs. http://www.regulations.gov/#!documentDetail:D=EPA-HO-OPP-2003-
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28 U.S. EPA (U.S. Environmental Protection Agency). (2008b). Evaluation of the carcinogenic potential
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30 of Pesticide Programs. http://www.regulations.gov/#!documentDetail:D=EPA-HO-OPP-
31 2003-0250-0089
32 U.S. EPA (U.S. Environmental Protection Agency). (2008c). Reregistration eligibility decision for
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39 U.S. EPA (U.S. Environmental Protection Agency). (2010). Toxicological review of hexavalent
40 chromium (external review draft). (EPA/635/R-10/004A). Washington, DC.
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48 is it essential, pharmacologically relevant, or toxic? : Springer.
49 http://link.springer.com/chapter/10.1007/978-94-007-7500-8 6
This document is a draft for review purposes only and does not constitute Agency policy.
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1 Vyskocil, A: Viau, C: Cizkova, M: Truchon, G. (1993). Kidney function in male and female rats
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11 biochemistry in male rabbits. Reprod Toxicol 21: 322-328.
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16 Zabulyte, D: Uleckiene, S: Kalibatas, I: Paltanaviciene, A: Tuozulynas, A: Gocentas, A. (2006).
17 Investigation of combined effect of chromium (VI) and nitrate in experiments on rats. Trace
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19 Zahid. ZR: Al-hakkak. ZS: Kadhim. AHH: Elias. EA: Al-jumaily. IS. (1990). Comparative effects of
20 trivalent and hexavalent chromium on spermatogenesis of the mouse. Toxicol Environ
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24 model. Part Fibre Toxicol 10: 45. http://dx.doi.org/10.1186/1743-8977-10-45
25
This document is a draft for review purposes only and does not constitute Agency policy.
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