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Page 1 United States Office of Chemical Environmental Protection Safety and Pollution Agency Prevention



## TSCA Workplan Chemical Risk Assessment

A ntimony Trioxide

CASRN: 1309- 64 -4

December 2012

NOTICE

This document is an External Review Draft . This information is distributed solely for the purpose of pre

- dissemination peer 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.DRAFT DO NOTE CITE OR QUOTE

Page 2 

## Table of Contents

**AUTHORS / CONTRIBUTO RS / ACKNOWLEDGEMENT**  **S / REVIEWERS**

........................................ 4

**GLOSSARY OF TERMS AND ABBREVIATIONS**

................................................................................ 5

**EXECUTIVE SUMMARY**

.................................................................................................................... 7

**CHAPTER 1: BACK GROUND AND SCOPE** 

....................................................................................... 9

**CHAPTER 2: SOURCES AND ENVIRONMENTAL FA**  **TE**

................................................................ . 12

INTRODUCTION

................................................................................................ ............................................. 12 A. C HEMICAL AND P HYSICAL P ROPERTIES OF A NTIMONY
........................................................................................... 12 B. P RODUCTION AND U SE
................................................................................................ ................................... 13 C. E NVIRONMENTAL F ATE
................................................................................................ ................................... 15 C ONCLUSION OF E NVIRONMENTAL F ATE
................................................................................................................. 19
**CHAPTER 3: ENVIRONM ENTAL ASSESSMENT** 

............................................................................. 20

A. E STIMATES OF E NVIRONMENTAL R ELEASES OF ATO D URING P ROCESSING AND U SE OF F LAME R ETARDANTS
..................... 20 B. ATO H AZARD C HARACTERIZATION FOR E COLOGICAL ORGANISMS
............................................................................ 27 C. E NVIRONMENTAL R ISK C HARACTERIZATION
......................................................................................................... 35
**REFERENCES**

................................................................................................ .................................. 48

**APPENDIX A: HUMAN H EALTH HAZARD SUMMARY** 

.................................................................. 58DRAFT DO NOTE CITE OR QUOTE

Page 3 

## List of Ta **bles**

Table 2

- 1. Physical

- Chemical Properties of ATO.

....................................................................................... 13

Table 2

- 2. US Manufacturers and Importers of ATO.

................................................................................ 14

Table 2

- 3. Major End

- Uses of Antimony in the US in 2011.

....................................................................... 14

Table 2

- 4. Environmental Bioconcentration/Bioaccumu lation of Antimony in Aquatic Species.

............. 18

Table 3

- 1. Summary of 2010 TRI Releases of Antimony Compounds. 1

..................................................... 21

Table 3

- 2. Summary of E

- FAST2 Results for Facilities Reporting TRI Releases, with Assumptions for Daily Release Amounts. a

................................................................................................................. 26

Table 3

- 3. Aquatic toxicity data for Sb 2 O 3 and SbCl 3 . ................................................................................. 28

Table 3

- 4. Soil Toxicity Data for Antimony Compounds.

........................................................................... 32

Table 3

- 5. Sediment Toxicity Data for Antimony Comp ounds.

.................................................................. 34

Table 3

- 6. Summary of All USGS

- NWIS and STORET data for Samples Above Concentrations of Concern per Media Type. a

.................................................................................................................... 37

Table 3

- 7. Summary of E

- FAST2 Results for Facilities Reporting TRI Water Releases.

.............................. 43



## List of **Figures**

Figure 2

- 1. Representative Chemical Structure of Senarmontite (CASRN 12412

- 52

- 1).

........................... 12

Figure 2

- 2. Representative Chemical Structure of Valentinite (CASRN 1317

- 98

- 2).

................................ . 12

Figure 3

- 1. Locations of USGS

- NWIS and STORET Monitoring Samples with Concentrations Greater Than COCs.

................................................................................................ ...................................... 40

Figure 3

- 2. Locations of USGS

- NWIS and STORET Monitoring Samples with Concentrations Less Than COCs.

................................................................................................ ...................................... 40

Figure 3

- 2. Locations of USGS

- NWIS and STORET Monitoring Samples with Concentrations Less Than COCs.

................................................................................................ ...................................... 41DRAFT DO NOTE CITE OR QUOTE

Page 4 

## Authors / Contributors / Acknowledgements / **Reviewers**

The report was developed by the Office of Pollution Prevention and Toxics (OPPT), Office of Chemical Safety and Pollution Prevention (OCSPP). The 2012 workplan risk assessments were prepared based on existing data and any additional information received up to June 15, 2012

.

EPA Assessment Team Lead: Sharon Oxendine, OPPT/RAD Team: Christina Cinalli, OPPT/EETD Rick Fehir, OPPT/EETD Kirsten Hesla, OPPT/CCD Jay Jon, OPPT/EETD Wen- Hsiung Lee , OPPT/EETD Timothy Lehman, OPPT/EETD Sara Pollack, OPPT/RAD Emma Lavoie, OPPT/DfE

Acknowledgements Port ions of this document were developed with support from :

Contractor name (contract number) Task

Abt Associates (EP -W- 08

- 010) Production and Uses Eastern Research Group (EP -W- 10

- 014) Releases Versar (EP -W- 10

- 005) Modeling, Monitoring SRC, Inc. ( EP -W- 09

- 027) Environmental Fate

Internal Peer Review ers H. Kay Austin , OPPT/EETD Stan Barone Jr. , OPPT/RAD

External Peer Review - A peer review panel is being arranged for this influential workplan assessment product based upon need and following Agency peer review guidance. The format will be a teleconference of an ad hoc panel meeting consisting of independent experts.DRAFT DO NOTE CITE OR QUOTE

Page 5 

## Glossary of Terms and Abbreviations

ATO Antimony trioxide BAF Bioaccumulation factor BCF Bioconcentration factor °C D egree Celsius CASRN Chemical Abstract Service Registry Number CBI Confidential business information

cm 3 Centimeters cubed COC Co ncentration of Concern d Day DMR Discharge Monitoring Report dw Dry weight EC 50 Half Maximal Effective Concentration E- FAST2 Exposure and Fate Assessment Screening Tool, version 2 EPA Environmental Protection Agency EU RAR European Union Risk Assessment Report FDA Food and Drug Administration GMATC Geometric m ean of m aximum a llowable t oxicant c oncentration IARC International Agency for Research on Cancer IUR Inventory Update Rule kg Kil o gram kg/yr Kil o gram(s) per year lb Pound LC 50 Half Maximal Lethal Concentration LOEC Lowest

- observed

- effect concentration
mg Milligram mg/kg Milligram(s) per kilogram mg/kg

- bw Milligram(s) per kilogram body weight mg/L Milligram (s) per liter mg/m 3 Milligram (s) per cubic meter μg/kg Microgram( s) per kilogram μg/L Microgram(s) per liter MMAD Mass median aerodynamic diameter NAICS North American Industry Classification System NHANES National Health and Nutrition Examination Survey NOAEC No

- observed

- adverse

- effect concentration NOEC No

- observed

- effect concentration NPDES National Pollution Discharge Elimination System NWIS National Water Information System OCSPP Office of Chemical Safety and Pollution Prevention OECD Organization for Economic Co

- operation and Development OPPT Of fice of Pollution Prevention and ToxicsDRAFT DO NOTE CITE OR QUOTE

Page 6 OSHA Occupational Safety and Health Administration PDM Probab i listic Dil u tion Model PET Polyethylene terephthalate PNEC Predicted no

- effect concentration POTW Publically o wned t reatment w orks PM Particulate m atter ppb Parts per billion PVC Polyvinyl chloride REACH Registration, Evaluation, Authorization and Restriction of Chemicals RWC Realistic worst case Sb Antimony Sb 3+ Trivalent antimony Sb 5+ Pentavalent antimony Sb(OH) 3 Antimonious acid Sb(OH) 6 - Antimonate SbCl 3 Antimony trichloride Sb 2 O 3 Antimony trioxide Sb 2 O 5 Antimony pentoxide STORET STOrage and RETrieval Data Warehouse TRI Toxics Release Inventory TSCA Toxic Substances Control Act US United States USGS United States Geological Survey WHO World Health Organization

ww W et W eight 7Q10 Refers to seven consecutive days of lowest stream flow over a 10

- year period based on USGS (t)

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## Executive Summary

The category, “Antimony and Related Compounds” was identified for assessment as part of the United States (US) Environmental Protection Agency (EPA) Existing Chemicals Management Program. EPA reviewed the readily available information on antimonial compounds, and selected antimony trioxide
, (CASRN 1309 -64-4 ; ATO; Sb 2 O 3 ), for further assessment based on: (1) high potential for exposure due to high production volume and widespread use in consumer products; (2) expected releases to aquatic, benthic, and terrestrial environments; (3) high persistence and low

- to

- moderate bioaccumulation potential; and (4) adverse effects reported in humans and laboratory animals.

ATO is the most widely used antimonial compound, accounting for roughly 80 percent of primary ( i.e. , mined) antimony consumption in the US ( USGS, 2011 )

. ATO is mainly used as a flame retardant synergist for halogenated flame retardants used in textiles and plastics ( Freedman et al. , 2003 ) ; approximately 25 million pounds (lbs) of ATO were consumed for this end

- use application in 2011 ( USGS, 2011 ) . The available US Geological Survey (USGS) data indicated no operational antimony mines or primary antimony production in the US in 2011, except for one company in Montana that produced antimony metal and oxide from a foreign feedstock ( USGS, 2012a ) . Approximately 87 percent of the ATO consumed in the US between 2007 and 2011 was imported, with the majority coming from China ( USGS, 2012a ).

Data from the US EPA’s Toxics Release Inventory (TRI) for the 2010 reporting cycle indicate d that approximately 970,000 lb s of ‘antimony compounds’ were released to land and roughly 15,700 lb s were released to water by industries that use or produce ATO

- co ntaining flame retardants ( TRI, 2010 ) . On

- site air releases totaled approximately 1 2,000 lb s , of which roughly
two

- thirds were from stack releases. A significant portion of the remaining fugitive air releases

are likely related to the combustion of fossil fuels; however, the precise quantity cannot be determined from TRI data.

Based on a review of the available data regarding antimony concentrations in food and environmental media, and biomonitoring data obtained from the latest National Health and Nutrition Exam ination Survey (NHANES), general population exposure to antimony is expected to be low. Because food and water are the primary sources of general population exposure, and the less toxic ( i.e. , pentavalent) form of antimony predominates in these media, sig nificant human health risks are not anticipated. This conclusion is supported by recent risk assessments completed for ATO in Canada and Europe. In addition, the US National Toxicology Program is currently conducting a two

- year carcinogen icity study on A TO; EPA will review these results when they become available. The remaining area of potential concern, for effects on ecological organisms
, was selected as the focus of th e current assessment. This decision was based on the Agency’s review of available e cotoxicity information and reported environmental releases of ‘antimony compounds’ in association with the manufacture and use of ATO

- containing flame retardants.DRAFT DO NOTE CITE OR QUOTE

Page 8 To assess the ecological risks associated with ATO releases, EPA identified hazard benchmarks ( i.e. , concentrations of concern ; COC ) for water

- , sediment

- , and soil

- dwelling organisms , which

were subsequently compared to measured antimony concentrations in these media. This information was obtained from two independent environmental monitoring datasets, the USGS National Water Information System (NWIS) (water [1972 to 2012]; sediment [1987 to 2011]; and soil [2005 to 2010]) ( USGS, 2012b ) and EPA’s S to rage and R et rieval ( STORET) Data Warehouse (water and sediment [2002 t o 2010) ( US EPA, 2012c )

. In addition, s ite

- specific modeling was co nducted for selected TRI facilities ( i.e. , those with identified use or production of ATO

- containing flame retardants) using EPA’s Exposure and Fate Assessment Screening Tool, version 2 (E

- FAST2) ( US EPA, 2010a ) to estimate ATO surface water concentrations.

To evaluate potential risks to ecological organisms, predicted surface water concentrations were compared to the identified hazard benchmarks

. Generally speaking, risks are indicated when the monitored or modeled exposure concentrations are above the COC. Under this paradigm, the concern for ecological risk associated with ATO use as a synergist in halogenated flame retardants is expected to b e low. Only one exceedance of the acute COC for aquatic organisms was predicted using the E

- FAST2 model, and very few ( i.e. , <1 percent ) of the environmental monitoring samples evaluated in this assessment exceeded the hazard benchmarks identified for ecological organisms. Perhaps more importantly, n o exceedance s were identified within the last three years ( 2009 to 2012 ).

EPA identified key sources of uncertainty relate d to limitations in the available hazard and
exposure information, and assumptions incorporated in the E- FAST2 model estimates of ATO surface water concentrations

. Although th ese uncertainties may limit data interpretation, they do not diminish the findings reported in this assessment

. The available data show very few instances ( i.e
., less than 0. 4 percent) where measured or predicted levels in the ambient environment exceed the hazard benchmark s identified for ecological organisms

.
In summary, risks are expected to be negligible for water

- , or sediment-dwelling organisms based on the following considerations:

• Use of the generic category, ‘antimony compounds’ and conservative assumption s regarding modeled releases likely overestimate exposure potential

.

• Use of highly sensitive ecological species to delineate conservative hazard benchmarks showed very few exceedances of the COC s

.

• Environmental monitoring data obtained during the last three years showed no exceed ance s of COCs

.

Th is assessment provides important insights regarding the potential risks of concern to ecological organisms associated with ATO ’s use in halogenated flame retardants. Measured and modeled concentrations of ATO are assumed to represent reasonable estimates of environmental exposures

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Page 9 

## Chapter 1: Background and Scope

The category, “Antimony and Related Compounds” was identified for assessment as part of the United States (US) Environmental Protection Agency ’s (EPA) ’s Existing Chemicals Management Program. EPA ’s Office of Pollution Prevention and Toxics (OPPT) reviewed the readily available information on antimonial compounds, and selected antimony trioxide
, (CASRN 1309

- 64 -4 ; ATO; Sb 2 O 3 ), for further assessment based on: (1) high potential for exposure due to high production volume and widespread use in consumer products; (2) expected releases to aquatic, benthic, and terrestrial environments; (3) high persistence and low

- to

- moderate bioaccumulation potential; and (4) adverse effects reported in humans and la boratory animals.

Global antimony (Sb ) demand is largely driven by the production of antimon ial compounds used in various consumer products such as medicines, polymers, resins
, and textiles. P entavalent antimonial compounds have been the mainstay of treatment for parasitic diseases ( e.g. , leishmaniasis and schistosomiasis) for over 70 years

. ATO production is currently the largest end

- use application for antimony, accounting for approximately 80 percent of global antimony consumption; a smaller port ion ( i.e., roughly 20 percent ) is associated with metallic

uses ( Roskill, 2011 )

.
ATO use as a synergist in hal ogenated flame retardants was selected as the focus of the current assessment because this end

- use application represents the largest global market for mined antimony. Global consumption of ATO in this sector has increased by approximately four percent / yr since 2000 ( Roskill, 2011 )

. Though ATO has no inherent flame retarding capacity
, when used as a synergist, it enhance s the effectiveness of halogenated flame retardants
, resulting in significant decreases in the total amounts of halogen ( e.g. , bromine or chlorine) needed to meet safety standards for flame resistance (Weil and Levchik, 2009) . ATO is also used as a condensation catalyst for the manufacture of polyethylene terephthalate (PET), a large

- volume commodity plastic used in bottles, films
, and various food contact applications. This end

- use application has been evaluated for safety and is regulated by the U S Food and Drug Administration (FDA) and other international authorities ( EU RAR, 2008 ; European Food Safety Authority,2004 ; Environment Canada/Health Canada, 2010 ) ; therefore, ATO use in PET plastics will not be further evaluated here.

A ntimonial compounds are naturally occurring in the earth’s crust , t hough not particularly abundant. Environmental releases may result from natural ( e.g. , volcanic eruptions, windblown dust) or anthropogenic sources ( e.g. , combustion of fossil fuels, nonferrous metal smelting). P entavalent antimony ( Sb 5+ ) is the most thermodynamically stable antimony species under most environmental conditions; however, t rivalent antimony ( Sb 3 + ) predominates under anaerobic conditions ( E nvironment Canada/Health Canada, 2010 )

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Page 10 Chemical speciation and route of exposure are major determinants of antimony toxicity in humans. Generally speaking, pentavalent antimony is less toxic to humans than the trivalent species . M ost antimony compounds are oxidized to the trivalent form when released to the environment; however, t he available evidence suggests that over time , f urther oxidation to the less toxic pentavalent form may occur under aerobic conditions ( EU RAR, 2008 )

.

G eneral population expos ure occurs mainly via ingestion of food and water, whereas inhalation and dermal contact are more common in occupational settings ( ATSDR, 1992 ) . Irritation at the point of contact ( e.g. , dermatitis, lung inflammation, pneum oconiosis) has been reported in workers following chronic inhalation exp osure ( NIOSH, 1978 ) . The US Occupational Safety and Health Administration (OSHA) regulates worker exposure to antimony compounds with a permissible exposure limit of 0.5 mg/m3 ( eight

- hour, time

- weighted average) ( OSHA, 2 012 ). ATO produces minimal systemic toxicity when administered at environmentally relevant concentrations due to poor systemic absorption
, which effectively limits bioavailability ( EU RAR, 2008 ; WHO, 2003 )

. Additional information regarding the human health effects associated with ATO exposure may be found in Appendix A.

Based on a review of the available data regarding antimony concentrations in food and environmental media, and biomonitoring data obtained from the US National Health and Nutrition Examination Survey (NHANES) , general population exposure to antimony is expected
to be low ( CDC, 2012 ). Because food and water are the primary sources of general population exposure, and the pentavalent ( i.e. , less toxic) form of antimony predominate s in these media, significant human health risks are not expected at ambient levels to which individuals may be exposed in the environment. This conclusion is supported by previous risk assessments for ATO in Europe and Canada ( EU RAR, 2008 ; Environment Canada/Health Canada, 2010 )

. In addition, the US National Toxicology Program is currently conducting a two

- year carcinogenicity study on ATO; EPA will review these results when they become available.

Unlike humans, t here is no conclusive evidence to support a significant difference in the ecological hazards associated with exposure to pentavalent or trivalent forms of antimony. When released to the environment
, antimony compounds release antimony ions upon dissolutio n and t he total antimony ion concentration is of most importan ce when assessing the persistence, bioaccumulation, and toxicity of antimony in the environment ( EU RAR, 2008 )

. S ubstances that yield comparable amounts of the same antimony ion may be used to characterize compounds for which less information is available. EPA used studies with antimony trichloride (S bCl 3 ) to assess hazards to aquatic - and sediment

- dwelling organisms because of limitations in the data available for ATO ( Skeaff et al. , 2012 ; Freedman et al. , 2003 ). EPA assumed no significant impact to the risk findings, as both compounds release comparable amounts of antimony ion upon dissolution.

EPA conducted an environmental exposure assessment based on monitoring data from the US Geological Survey (USGS) National Water Information System (NWIS) ( USGS, 2012b ) and the US Environmental Protection Agency ( EPA ) S to rage and R et rieval (STORET) D ata Warehous e ( US EPA, 2012c ), including a total of 5,49 3 water samples ( i.e. , 3,64 3 in USGS

- NWIS and 1,850 inDRAFT DO NOTE CITE OR QUOTE

Page 11 STORET). In addition, the E

- FAST2 model ( US EPA, 2010a ) was used to estimate surface water concentrations based on water releases reported in the 2010 TRI. Because TRI does not indicate a time

- frame for reported water releases, the 2010 data were modeled using two exposure scenarios, based on total release s occurring over a period of 250 or 24 days/yr. This was done to provide a range of exposure estimates based on reported water release s from selected TRI facilities.

To assess potential ecological risks
, EPA identified hazard benchmarks
, also designated as

“ concentrations of concern ” (COCs) for water

- , sediment

- , and soil

- dwelling organisms that were subsequently compared to measured antimony concentrations in these media. The scientific literature was reviewed to identify and evaluate the available information for use in hazard characterization. Publications were critically evaluated based on adherence to specific test guidelines, the endpoints used to assess toxicity, and the amount of detail provided in each study report. COCs were calculated using conservative ecotoxicity values derived from the most robust studies available in the published literature.DRAFT DO NOTE CITE OR QUOTE

Page 12 

## Chapter 2: Sources and Environmental Fate

INTRODUCTION

In order to assess the potential ecological risks of concern that may be associat ed with ATO use as a synergist in halogenated flame retardants , a firm understanding of the physical and chemical properties, environmental releases , and the ultimate fate in environment al media are important. These topics are introduced here and the ATO risk characterization is discussed in Chapter 3.



### A. C HEMICAL AND 

### P HYSICAL 

### P ROPERTIES OF 

### A NTIMONY

Antimony ( Chemical Abstracts Service Registry Number [ CASRN ] 7440

- 36 -0) is a naturally occurring metalloid that belongs to Group 15 of the periodic table; i t can exist in +5, +3, 0, or -3 oxidation states, with +5 ( i.e., pentavalent) and +3 ( i.e., tri valent) being most common.

A TO is a dimorphic crystalline solid that exist s in cubic ( i.e., senarmontite ; CASRN 12412

- 52 -1) and orthorhombic configuration s ( i.e., valentinite ; CASRN 1317

- 98 -2)

. Cubic s enarmontite is stable below 570 °C, wh ereas valentinite ( i.e., infinite double chains) is formed above this temperature ( Freedman, et al
., 2003 ). The cubic form is shown in Figure 2-1, and the orthorhombic form is shown in Figure 2 -2.

Figure 2- 1. Representative Chemical Structure of Senarmontite (CASRN 12412

- 52

- 1)

.

O

O O
Sb Sb O

O
Sb O

O O Sb Sb O

Sb O

O

Figure 2 -2

. Representative Chemical Structure of Valentinite (CASRN 1317

- 98

- 2)

. O Sb

O O

Sb Sb O

Sb O ODRAFT DO NOTE CITE OR QUOTE

Page 13 ATO exhibits negligible vapor pressure at 25 °C and tends to be soluble in hydrochloric acid
, tartaric acid, and caustic alkalies ; i t is insoluble in organic solvents and only slightly soluble in
water ( Patnaik, 2003 ) . The most reliable water solubility value ( 2.76 mg/L ) was measured in reconstituted standard water ( ISO 6341) at 22.2 °C during a seven

- day equilibration period under slightly alkaline conditions ( pH 8 ) ( EU RAR, 2008 ) . Typical physi cal

- chemical properties of ATO can be found in Table 2 -1.

Table 2

- 1 . Physical

- Chemical Properties of ATO. Property Value Comment Physical state at 25 °C White solid
Particle size 0.2

- 13.89 μm a Estimated vapor pressure at 25 °C <1 × 10 - 6 torr Water solubility at 22.2 °C 2.76 mg/L at pH 8 b Value determined after 7 days In reconstituted standard water, l oading = 100 mg/L

. Water solubility at 20 °C 19.7 mg/L at pH 7 c 25.6 mg/L at pH 9 c 28.7 mg/L at pH 11 c Value determined after 24 hours in distilled water

.

Melting point 656 °C d Boiling point 1425 °C d

a Weidenfeller (2005) as cited in EU RAR (2008).
b LISEC (2002 ) as cited in EU RAR (2008 ).

c Umweltanalytik GmbH (1993 ) as cited in EU RAR (2008 ).
d Lide (2000 as cited in the EU RAR, 2008 ).



### B. P RODUCTION AND 

### U SE

S everal types of antimony compounds are known to exist in nature ; however, the mineral stibnite is the primary source of processed antimony in commerce. I n terms of the total production volume and potential end

- use applications, ATO is the most widely used synthetic antimony compound.

N o primary antimony production occurred in the US in 2011 , with the exception of one company that produced antimony metal and oxide from a foreign feedstock ( USGS, 2012a )

. A pproximately 87 percent of the ATO consumed in the US b etween 2007 and 2011 was imported from other countries ( USGS, 2012a )

.
Currently, there are no antimony mines operating within the US ( USGS, 2006 ) ; t he two main ATO producers are Chemtura Corporation and US Antimony Corporation ( USGS 200 5 ; Roskill, 2011 ). While neither is listed as a manufacturer on the 2006 Toxic Substances Control Act ( TSCA ) Inventory Update Reporting (IUR) rule, their respective websites indicate that the y currently manufactur e and sell ATO products ( Chemtura, 2012 ; US Antimony Corporation, 2012 ) . Table 2

- 2 provides a list of companies that manufacture or import ATO in the US.DRAFT DO NOTE CITE OR QUOTE

Page 14 Table 2

- 2. US Manufacturers and Importers of ATO

. Company City State Manufacture Import
Arkema Inc. Philadelphia PA CBI CBI
Chemson Inc. Philadelphia PA No Yes E. I. du Pont de Nemours and Company Wilmington DE No Yes Eastman Kodak Company Rochester NY No Yes Ferro Corporation Washington PA No Yes

General Electric Company Mt. Vernon IN No Yes Bridgeville PA No Yes Washington WV No Yes ICC Chemical Corporation New York NY No Yes
LG Chem America, Inc. Englewood Cliffs NJ No Yes PolyOne Corporation Avon Lake OH No Yes Sojitz Corporation of America New York NY No Yes United Mineral & Chemical Corp. Lyndhurst NJ No Yes

CBI = confidential business information

. Source: US EPA (2010b ).

A pproximately 2 40 million pounds ( lbs ) of ATO was produced globally in 2005 , with the majority of production taking place in China ( The Chemical Compan y, 2012 )

. Total combined p roduction of ATO in the US and Mexico was estimated at approximately 52.8 million lbs in 2005 ; however, the total amount of ATO consumed in the US during this time period was estimated at roughly 70 million lbs ( International Antimony Association, 2010 ).

ATO is primarily use d as a synergist in halogenated flame retardants applied to textiles and plastics; other reported applications include use as a plastic stabilizer, catalyst precursor, paint pigment, fining agent
, or antisolarant ( Freedman et al. , 2003 ). Other m ajor end -u se application s for ATO are shown in Table 2

- 3.

Table 2

- 3. Major End

- Uses of Antimony in the US in 2011

.
End

- Use Market Share (%) Flame retardant synergist 36 Transportation (including batteries) 23
Chemicals 16 Ceramics and glass 12
Other 13

Source: USGS (2012a ).DRAFT DO NOTE CITE OR QUOTE

Page 15 T hough ATO has no inherent flame retarding capacity ( US EPA, 2012a ), when used as a synergist in halogenated flame retardants , it decreases the amount of halogen needed to impart acceptable flame resistance ( USGS, 2004 ; Weil and Levchik, 2009 ) . ATO interacts with chloride or bromide to form flame quenching antimony trichloride or antimony tribromide ( Weil and Levchik, 2009 ) . In many instances, ATO is added to ( rather than incorporated in ) the actual polymer matrix ( AkzoNobel, 2012 ; Albemarle, 2000 ; ChemEurope, 2004 )
, occurring as a separate , non

- reactive ( i.e
., non

- covalently bonded ) phase. ATO may be found in a number of flame

- retarded products, including electrical equipment, wires, automotive parts, building materials, furniture, carpets, mattress covers, plastics
, and textiles ( Environment Canada/Health Canada, 2010 )

. T he average ATO content in flame retardant formulation s used
to treat plastics generally ranges from 25 to 33 percent by weight
, whereas the relative abundance of ATO in the final ( flame

- retarded ) product can range from 1.5 to 12 percent ( USGS, 2004 ). Approximately 25 million lbs of ATO were consumed by this market sector in 2011 , as compared to approximately 50 million lbs in 1999

.


### C. E NVIRONMENTAL 

### F ATE

ENVIRONMENTAL PERSISTENCE OF ATO

Though not particularly abundant, antimon ial compounds are naturally occurring in the earth’s crust. Environmental releases may result from natural ( e.g. , volcanic eruptions, windblown dust) or anthropogenic sources ( e.g. , combustion of fossil fuels, nonferrous metal smelting).

ATO is an inorganic metal oxide; therefore, a fate analysis based on the octanol

- water partition coefficient or the organic carbon

- water partition coefficient is not applicable. Typical mass balance fugacity modeling is also inapplicable to ATO ( or other metal ions ) released upon dissolution, because these substances exert zero partial pressure and fugacity in air ( Diamond et al. , 1992 ) . ATO is persistent in all media ( i.e. , air, water, soil, and sediment)
, because the antimony ions issu ed upon dissolution cannot be degraded. Depending upon the ambient conditions ( e.g ., pH , redox potential , dissolved oxygen content )
, ATO ( Sb 2 O 3 ) may be oxidized to antimony pentoxide ( Sb 2 O 5 ) , but this transformation may be reversed under anaerobic conditions in the environment ( Environment Canada/Health Canada, 2010 )

.

Fate in Wastewater Treatment Effluents released from industrial facilities may contain antimony as a result of m aterial handling and/or washing of equipment. This material may end up in industrial or municipal wastewater treatment plants, and as a result of alkalinization processes, a fraction will be deposited in sludge. Because sludge is commonly spread on agricultural fields, this application could potentially release antimony to soils, which may end up in local groundwater and/or surface waters because of soil leaching and runoff ( Environment Canada/Health Canada, 2010 ).DRAFT DO NOTE CITE OR QUOTE

Page 16 Fate in Water Due to the weathering of soils and sediment and the run

- off from terrestrial environments, aquatic eco systems ( e.g. , str eams, rivers, ponds, lakes, bays, etc .) may serve as a sink for ATO released to the environment. The aqueous chemistry of antimony is complex and involves a wide range of oxygenated species whose stabilities depend mainly on the acidity and oxygen content of the receiving waters. D issolved antimony can transform into a variety of species and form num erous complexes with dissolved ligands present in the aquatic environment ( Schecher and McAvoy, 1992 ; Tipping, 2002 )

. T he neutral species antimonious acid, [ i.e., Sb(OH) 3 ] , is expected to be the primary form issued upon dissolutio n and hydrolysis

.
Antimony concentrations in unpolluted natural waters are low, usually on the order of one ppb or less; levels detected in ocean surface waters tend to be even lower ( i.e., approximately 0.2 ppb; Filella et al. , 2009 ). Pentavalent antimony also has been detected in an aerobic environments in association with the following transport processes: movement associated with detritus sinking from aerobic waters, biotransformation by marine organisms, and advection of surface waters containing high levels of Sb 5+

. All of these potential transport mechanisms assume a slow rate of conversion to Sb 3+ in the absence of oxygen ; the rate constant for this reaction was estimated at approximately 1.1 × 10 -6 days -1 ( Cutter , 1992 )

.
In a comprehensive review of the published literature on antimony speciation in natural waters, Filella et al. (2009 ) reported that relatively small amounts of Sb 3+ were detected in oxygenated waters. This finding has been corroborated by other authors, such as Garbos e t al. (2000 ) who determined that the majority of antimony detected in natural waters ( i.e
., 96 to 99 percent) was Sb 5+

. Cutter (1992 ) evaluated the rate of oxidation of Sb 3+ to Sb 5+ b y measuring the depth profiles for antimony species in the upper 100 meters of the Black Sea. No Sb 3+ was detected at surface levels; however, a gradual increase in the Sb 3+ concentration (in association with a decline in Sb 5+ levels) was observed at depths beyond 60 meters. The highest concentration of Sb 3+ was found in deeper, largely anaerobic waters ( i.e
., 90 to 100 meters). An estimated pseudo

- first

- order rate constant of 0.008 day -1 was calculated for the oxidation of Sb 3+ to Sb 5+

, corresponding to a residence time of approximately 125 days for Sb 3+ in natural waters.

Fate in Soil and Sediment Due to the tendency to sorb to solid particles in aquatic media, a significant portion of dissolved antimony will end up in sediment, as evidenced by the logarithmic sediment

- water partition coefficient (log K sdw ) for antimony, which generally ranges from 2.5 to 4.8 ( Environment Canada/Health Canada, 2010 ). This can occur through adsorption to suspended particles as they settle out of solution ( Hamilton

- Taylor et al. , 1984 ), or through precipitation of calcium antimonite ( EU RAR, 2008 )

. A portion of undissolved ATO may also occur in moist soils. B ioaccessibility to soil

- dwelling organisms is largely governed by mobility and solubility in environmental media, which is limited under acidic conditions ( i.e ., pH 3

- 4) by adsorption to hydrous oxides of iron, manganese, and aluminum ( HSDB, 2012 ) . Changes in pH can also influence valence state, which further impacts solubility and leaching potential. Leaching experiments indicate that Sb 5+ is the predominant antimony species issu ed under normal environmental conditions ( ≥ pH 6.3), whereas Sb 3+ pred ominates at pH 2.7 ( HSDB, 2012 )

.DRAFT DO NOTE CITE OR QUOTE

Page 17 Fate in Air Combustion processes are a major source of antimony air releases . Antimony particulates are removed from the atmosphere by gravitational settling or wet and dry deposition, depending on particle size. Larger particles are generally removed within hours, whereas smaller particles require a longer period (on the order of weeks). In a model comparing part icle size to volatility, antimony exhibited an average atmospheric half

- life of approximately 3.2 days ( ATSDR, 1992 ).

As a non

- gaseous element with a negligible vapor pressure, ATO is emitted to air principally in the form of fine particulate matter (PM). The E uropean Risk Assessment Report ( EU RAR, 2008 ) states that : (1) combustion or incineration processes are likely to transform antimony compounds to ATO regardless of the pre

- incinerated form of antimony; (2) anthropogenic activities m ay result in long

- range transport of a portion of ATO emitted to air; and (3) there are indications that a significant portion of the ATO present in the atmosphere may be water soluble. A study of wet and dry deposition over an eight

- week period in an are a that was presumably far from release sources found that 87 percent of the deposited antimony was dissolved in rain, 11 percent occurred as PM in rain, and approximately two percent was removed from air via dry deposition of PM ( Stössel and Michaelis, 1986 ; as cited in EU RAR, 2008 ).

ENVIRONMENTAL TRANSFORMATION, BIOAVAILABILITY, AND BIOACCUMULATION

Transformation Antimony can transition between various organic and inorganic forms in the environment ( Filella et al. , 2007 ) . For example, microorganisms have been shown to biomethylate relatively small amounts (< 0.1 percent) of antimony, and binding to metal hydroxides has been associated with the oxidation of Sb 3+ to Sb 5+ ( ATSDR, 1992 ; Filella et al. , 2007 ; HSDB, 2012 )

. These transformations are important because they impact antimony mobility in environmental media, as well as the bioavailability, and toxicity to ecological organisms

.
Bioavailability Antimony is a natural constituent of soils and sediments. It is subject to transformations in environmental media that may make it more or less bioavailable depending on various fac tors, such as valence, pH, soil or sediment type, and the oxic or ionic conditions of aqueous environments ( EU RAR, 2008 )

. In addition , b ehavior in environmental media ( e.g. , sorption/ desorption) and availability to soil - or sediment

- dwelling organisms is influenced by the presence of other metals such as iron, manganese, and aluminum ( EU RAR, 2008 )

.
In aquatic systems, the bioavailability of antimony compounds may be impacted by solubility. Water s olubility is dependent up on pH , which may increase the bioavailability of antimony to aquatic organisms at environmentally relevant pH levels ( EU RAR, 2008 )

. In natural waters, antimony will occur a lmost exclusively as Sb(OH) 3 and [Sb(OH) 6 - ] via hydrolysis of Sb 3+ and Sb 5+ ions, respectively ( OECD, 2008 ).DRAFT DO NOTE CITE OR QUOTE

Page 18 Bioaccumulation Some published studies suggest a potential for antimonial compounds to accumulat e in aquatic organisms such as fishes, plants, and invertebrate s ( EU RAR, 2008 ) ; however, there is considerable uncertainty regarding the derivation of these values. For example, the data used may be available in the form of an abstract or robust summary in which the underlying methodology used f or sample analyses are not reported , making it diffic ult to evaluate data quality

.
Antimony is not expected to exhibit significant bioconcentration potential in aquatic organisms. The bioaccumulation of metals in aquatic ecosystems is largely governed by trophic feeding groups, with detritivores accumul ating higher levels than herbivores or predatory groups. For example, Corbicula fluminea , a filter

- feeding clam that consumes algae, bacteria, and fine detritus, has been reported to bioaccumulate antimony to a greater extent than other predators or omnivores ( Duran et al. , 2007 ) ; however, Baeza et al. (2010 ) found no significant correlation between antimony bioaccumulation in C. flu minea and elevated antimony levels in sediments.

Heier et al. (2 009 ) determined that antimony accumulation is minimal in brown trout ( < 0.08 μg/L). In another study, Gal et al. (2007 ) evaluated antimony levels in earthworms taken from a mining site w here th e antimony concentrations in soil rang ed from 10 to 1,200 mg/kg. In the two species of earthworms evaluat ed, antimony concentrations ranged from 0.72 to 26 mg/kg dw ; however, the calculated bioconcentration factors ( i.e
., the ratio of antimony in biota to that in soil) were less than one, indic ating minimal bioconcentration potential for these organisms

. Additional information on antimony bioconcentration in saltwater and freshwater species can be found in Table 2 -4.

Table 2 -4 . Environmental Bioconcentration/Bioaccumulation of Antimony in Aquatic Species. Salt Water Species a Fresh Water Species b

Fish BCF c : 0.15 (Two spot goby); BCF: 0.40 (Shanny) Fish BAF c : 0.43 ( Labeobarbus kimberleyensis )

Aquatic invertebrate No data Aquatic invertebrate BAF c : 5.65 ( Hyalella azteca )

Algae BCF c : 17.00 (Coralline or red algae) Algae BCF c : 24.00 ( Chlorella vulgaris )

a US EPA (2012b ).
b Environment Canada/Health Canada (2010 ).

c BAF = bioaccumulation factor; BCF = bioconcentration factorDRAFT DO NOTE CITE OR QUOTE

Page 19 

### C ONCLUSION OF 

### E NVIRONMENTAL 

### F ATE

ATO is an environmentally persistent metalloid that exhibit s high persistence and low

- to

moderate bioaccumulation potential. The octanol

- water and organic carbon

- water partition coefficients are not particularly useful for assessing the environmental fate of ATO, because inorganic antimony c ompounds are outside the domain of most existing fugacity models. Generally speaking, Sb 5+ is the most thermodynamically favorable antimony species under aerobic conditions in the environment; however, Sb 3+ predominates under an aerobic conditions. Antimo ny is primarily removed from the atmosphere via wet and dry deposition. Mobility in soil and sediment is influenced by various factors, such as metal composition and pH; increased a dsorption and decreased mobility occur in the presence of oxidized iron,

m anganese, or aluminum and is maximal under acidic conditions.DRAFT DO NOTE CITE OR QUOTE

Page 20 

## Chapter 3: Environmental Assessment

A. E STIMATES OF 

### E NVIRONMENTAL 

### R ELEASES OF 

### ATO D URING 

### P ROCESSING AND 

### U SE OF 

### F LAME 

### R ETARDANTS

I nformation presented in this section focuses on industrial releases from sectors associated with ATO

- based flame retardants used in plastic, rubber, and textile manufacturing.

INTRODUCTION

Domestic release data were identified from EPA’s TR I which contains publically available information on releases
, including on - and off

- site transfer s , and other recycling information submitted by industry to comply with environmental regulations. TRI information obtained for ATO is summarized below

.

TRI Data ATO is not specifically listed on the TRI , but is included within the broader category of

‘ antimony compounds ’ , which covers all chemicals that contain antimony. As such, it is not possible to separate ATO releases from those of other antimony

- containing chemicals reported in the TRI database.

To identify the selected TRI reporting facilities, EPA examined the primary North American Industry Classification System ( NAICS ) codes reported in the 2010 TRI for antimony compounds

. A full description of the 6- digit NAICS codes is available from the Department of Census ( http://www.census.gov/eos/www/naics/ ). The NAICS codes description s i nclude a general heading and several subcategories. A total of 270 facilities reported releases of antimony compounds to the TRI in 2010 (Table 3

- 1). The majority of releases were sent to land and other disposal media (which include on - and off

- site transfers
, landfill, underground injection, land treatment, surface impoundments, and other transfers for off

- site disposal). The on - and off

site land and other disposal of antimony compounds totaled approximately 970,000 lbs , of which, approximately one

- third w as associated with on

- site land releases from nine facilities (NAICS code 3 25188 - All Other Basic Inorganic Chemical M anufacturing). The 2010 TRI water releases reported for antimony compounds were significantly less than the reported land releases, totaling approximately 15,700 lbs

. Of the total water releases, approximately 3,100 lbs were associated with direct surface water discharges, and approximately 12,600 lbs were transfer red to publicly owned treatment works ( POTW s) or other off

- site water treatment facilities.DRAFT DO NOTE CITE OR QUOTE

Page 21 Table 3 -1

. Summary of 2010 TRI Releases of Antimony Compounds

. 1

Life Cycle Stage NAICS Total Number of Facilities Reporting On

- site and Off

- site Releases and Disposal (lb s /yr) a Primary NAICS Code Description Total Air Releases Total Water Releases b Total Land and Other Disposal

Manufacture of a ntimony o xides 3 2518 8 All other basic inorganic chemical manufacturing 9 2,106 573 364,113

Plastics material and resin, synthetic rubber, and fiber manufacturing 3 2521 1 Plastics m aterial and r esin

m anufacturing 27 884 4,939 47,394

3 2521 2 Synthetic rubber manufacturing 2 85 26 2,497
3 2522 2 Noncellulosic organic fiber manufacturing 5 08 186 700

Total 34 1,377 5,151 50,592
Plastics compounding and conversion 3 2599 1 Custom c ompounding of
p urchased r esins 55 1,231 540 81,014

3 2611 3 Unlaminated p las t ics f ilm and

s heet (except p ackaging)

m anufacturing 18 339 110 7,078

3 2612 1 Unlaminated plastics profile shape manufacturing 2 3 0 4,648

3 2613 0 Laminated p lastics p late, s heet (except p ackaging), and s hape

m anufacturing 2 10 1 3,229

3 2615 0 Urethane and o ther f oam product (except p olystyrene)

m anufacturing 3 0 0 0

3 2619 9 All other plastics product manufacturing 25 330 10 68,625DRAFT DO NOTE CITE OR QUOTE

Page 22 Table 3 -1

. Summary of 2010 TRI Releases of Antimony Compounds

. 1

Life Cycle Stage NAICS Total Number of Facilities Reporting On

- site and Off

- site Releases and Disposal (lb s /yr) a Primary NAICS Code Description Total Air Releases Total Water Releases b Total Land and Other Disposal

Total 105 1,914 661 164,594
Rubber compounding and conversion 3 2622 0 Rubber and p lastics h oses and b elting m anufacturing 8 14 44 20,876

3 2629 1 Rubber p roduct m anufacturing for

m echanical use 3 30 0 9,106

3 2629 9 All other rubber product manufacturing 16 1,163 33 24,298

Total 27 1,208 77 54,280 Fabric Finishing 3 1321 0 Broadwoven fabric mills 2 60 0 2,058
3 1323 0 Nonwoven fabric mills 1 0 2,167 11,328
3 1331 1 Broadwoven fabric finishing mills 4 53 1,139 2,707
3 1331 2 Textile and f abric f inishing (except broad woven f abric) m ills 1 669 669 6,025

3 1332 0 Fabric coating mills 15 2,893 4,927 88,465
Total 23 3,675 8,902 110,583 Fiberglass insulation manufacturing 3 2799 3 Mineral wool manufacturing 3 0 0 4,765

Drawing an d insulating of wires and fiber optic cables 331422 Copper w ire (except m echanical) d rawing 20 844 90 60,626

335921 Fiber optic cable manufacturing 2 0 0 4,815
335929 Other c ommunication and e nergy

w ire m anufacturing 38 3 25 101,160DRAFT DO NOTE CITE OR QUOTE

Page 23 Table 3 -1

. Summary of 2010 TRI Releases of Antimony Compounds

. 1

Life Cycle Stage NAICS Total Number of Facilities Reporting On

- site and Off

- site Releases and Disposal (lb s /yr) a Primary NAICS Code Description Total Air Releases Total Water Releases b Total Land and Other Disposal

Total 60 847 115 166,601
Plastic

- containing electronic/electrical product manufacturing 335931 Current

- c arrying w iring d evice

m anufacturing 5 255 5 17,733

Textile product mills and apparel manufacturing 3 1411 0 Carpet and r ug m ills 3 255 207 1,942
3 1499 9 All other miscellaneous textile product mills 1 0 0 31,415

Total 4 255 207 33,357

1 See : supplemental data file titled “Supplemental 2010 TRI Data for the TSCA Workplan Chemical Risk Assessment of ATO (External Review Draft). pdf ”

a Mass in lb s /y r can be converted to kg/yr by multiplying lbs /yr by 0.4536 kg /lb.
b Includes transfers to POTW s and other off

- site wastewater treatment facilities.DRAFT DO NOTE CITE OR QUOTE

Page 24 The on

- site air releases of antimony compounds totaled approximately 12,000 lbs , of which approximately two

- thirds were from stack air releases and one

- third were from fugitive air releases. It is expected that a significant portion of these releases are associated with the combustion of fossil fuels as opposed to the use of ATO

- containing flame retardants, the quantity of which cannot be determined from TRI data.

TRI releases reported for ‘ antimony compounds ’ are used as a surrogate for ATO in this exposure assessment. It is assumed that the total releases reported for ‘ antimony compounds ’ would be higher than those that may be expected for ATO alone. Table 3 -2 summarizes the most recent TRI infor mation for releases reported by industry sectors identified using the NAICS codes covered under the scope of this assessment ( i.e
., those indicating use or production of ATO

- containing flame retardants ).

MONITORING OF ATO IN THE ENVIRONMENT

EPA developed s ubsets of environmental m onitoring data obtained from targeted searches of the USGS

- NWIS and EPA’s STORET databases in July 2012

. A pproximately 8,500 water, sediment and soil samples were collected from these data bases

. Data collection centered on the 10 states in which selected TRI facilities ( i.e.
, those reporting use or production of ATO

containing flame retardants) were located

.
Compilation of Environmental Monitoring Data from the USGS

- NWIS Database Environmental monitoring d ata were downloaded from the USGS

- NWIS website ( http://nwis.waterdata.usgs.gov/usa/nwis/qwdata

, accessed in July 2012 ). A subset 1 of the larger dataset, which spanned more than 30 years (1987 to 2011), was used for the exposure
assessment.

The dataset was limited to monitoring samples obtained from states ( i.e. , AL, IN, KY, NC, NJ, NY, SC, TN, TX, and VA) that included at least one of the 1 5 TRI facilities identified under the scope of this assessment. The USGS dataset was further refined i.e., to focus specifically on water, sediment, and soil samples obtained from these regions

. T he monitoring data were split into two groups: (1) measured antimony concentrations from all years, and (2) measured antimony concentrations obtained from 2009 to 2012.

Compilation of Environmental Monitoring Data from the STORET Database Another large source of environmental monitoring data was obtained from EPA’s STORET website ( http://www.epa.gov/storet/dw_home.html , accessed in July 2012) . The STORET dataset included measured antimony concentrations in water and sediment only and was limited to samples taken from states that included at least one of the TRI facilities identified in

1 See attached file titled “Supplemental subset of USGS

- NWIS Dataset for the TSCA Workplan Chemical Risk Assessment of ATO (External Review Draft).xlsx”DRAFT DO NOTE CITE OR QUOTE

Page 25 Table 3

- 2. 2 The STORET data were divided into two categories: (1) concentrations measured in
wat er (μg/L), and (2) concentrations measured in sediment (mg/kg dw ).

EXPOSURE ASSESSMENT

This purpose of this assessment was to evaluate ATO exposures to water

- , soil

- , and sediment

dwelling organisms. T wo separate approaches based on environmental monitoring data and modeled water release s were used to investigate selected TRI facilities.

In the first evaluation, approximately 8, 5 00 data points were obtained from the USGS

- NWIS and EPA’s STORET database s. A large amount of water and sediment data was available from these sources. Data collection centered on the 10 states in which the selected TRI facilities ( i.e

. , those reporting use or production of ATO

- containing flame retardants) were located

. N one of the actual monito ring sites were located within the primary watershed of the TRI facilities identified under the scope of this assessment. For this reason, a second approach
, based on reported TRI releases
, was utilized to estimate aquatic exposures using the E- FAST2 model (available at http://www.epa.gov/oppt/exposure/pubs/efast.htm ).

Three selection criteria were used to identify TRI facilities: (1) reported water releases of ‘antimony compoun ds’ above 1 lb /yr; (2) reported NAICS codes that indicate possible use of ATO as a flame retardant synergist ; and (3) stream releases for which the lowest streamflow data, or “7Q10” value ( i.e.
, the average consecutive seven

- day stream flow data over a 10

- year period) was available. The 7Q10 streamflow data are linked to the National Pollution Discharge Elimination System (NPDES) codes for each facility, which were found using EPA’s Discharge Monitoring Report (DMR) Pollutan t Loading Tool (available at http://cfpub.epa.gov/dmr/error_correction.cfm ).

Using this selection approach, EPA identified 36 TRI facilities ( TRI 2010 ) that reported water releases of ‘antimony compounds’ and listed primary NAICS codes associated with ATO use as

a synergist in halogenated flame retardant s ; 33 of these indicated releases > 1 lbs /yr. NPDES numbers matching the reported latitudes and longit udes were found for 1 4 TRI facilities provid ing site

- specific stream flow rates for use in the E- FAST2 model. A summary of the input data used for the E- FAST 2 model is provided in T able 3

- 2.

2 See attached file titled “Supplemental subset of STORET Datase t for the TSCA Workplan Chemical Risk Assessment of ATO (External Review Draft).xlsx”DRAFT DO NOTE CITE OR QUOTE

Page 26 Table 3

- 2. Summary of E

- FAST2 Results for Facilities Reporting TRI Releases, with Assumptions for Daily Release Amounts

. a

Facility Name Latitude L ongitude NPDES Code Total Surface Water Discharge Based on TRI (lb s) Scaled Annual Release

(kg) Results Daily Release (250 Days ) (kg) Results Daily Release (24 D ays) (kg)
Eastman K odak Co TN E astman Co D iv , K ingsport , TN, 37662 36.5 1982 3

- 82.540429 TN0002640 1, 042 557.22 2.23 23.22

G uilford East Plant , K enansville , NC, 2834 9 35.0 2158 7

- 77.859994 NC0002305 669 357.75 1.43 14.91
A uriga Polymers Inc. S partanburg Facility , Spartanburg
, 2930 7 35.030528

- 81.86 1366 SC0002798 320 171.12 0.68 7.13

S abic I nnovative P lastics US LLC, S elkirk , NY, 1215 8- 0145 42.575416

- 73.853563 NY0007072 250 133.69 0.53 5.57
S abic I nnovative P lastics Mt . V ernon , LLC, M ount V ernon , IN, 476 20

- 9364 37.906389

- 87.9 2777 8 IN0002101 250 133.69 0.53 5.57

Sage Automotive Interiors A bbeville P lant , A bbeville , SC, 2962 0 34. 1672 22

- 82.37 1389 SC0000353 248 132.62 0.53 5.53

P erformance F ibers O perations I nc. , S alisbury P lant
, S alisbury , NC, 7 2814 7 35.7 2023 4

- 80.6 1086 7 NC0004944 95 50.80 0.20 2.12

D upont T eijin F ilms , C hester , VA, 2383 6 37.346259

- 77. 2858 11 VA0003077 51 27.27 0.11 1.14
H aywood C o, B rownsville , TN, 380 121797 35.605911

- 89. 2400 68 TN0041939 28 14.97 0.06 0.62
B ayshore I ndustrial La P orte , TX, 77571 29.63038

- 95.030311 TX002279 9 13.505 7.22 0.03 0.30
C ovalence Adhesives , F ranklin , KY, 4 2134 36.753889

- 86.575278 KY0074659 5 2.67 0.01 0.11
G eneral C able I ndustries I nc ., M arion
, IN, 46953

- 2406 40.55425

- 85.654944 IN0002372 5 2.67 0.01 0.11 Borealis Compounds I nc. , P ort Murray , NJ, 07865 40.8 1336 1

- 74.888111 NJ00 2865 7 5 2.67 0.01 0.11
C erro Wire LLC , H artselle , AL, 35640 34.4 1291 3

- 86.9 1739 5 AL0054674 5 2.67 0.01 0.11

a These screening

- level estimates are based on a range of days of release
, which may not represent actual releases and environmental concentrations at these facilities. NPDES = National Pollution Discharge Elimination SystemDRAFT DO NOTE CITE OR QUOTE

Page 27 Because TRI facilities do not indicate the total number of release days per year ( i.e., a required input for E

- FAST2 modeling), two release scenarios were modeled (assuming total TRI releases of ‘antimony compounds’ reported during the 2010 reporting cycle occurred over a period spanning 24 or 250 days). The first scenario ( i.e. , assuming total releases occurred over a period of 250 days) was selected based on the fact that a typical 260 work days and 10 holidays generally occur dur in g a calendar year

. 3 The more conservative scenario ( i.e. , 24 release days/yr), was selected because some facilities may only incur releases as a result of bi

- monthly cleaning practices. 4 Both release scenarios were used to estimate surface water concentra tions using the E

- FAST2 model of water releases reported by the 1 4 TRI facilities identified for consideration in this assessment (Table 3

- 2). T hese release scenarios were developed to provide a reasonable range of estimated surface water concentrations for assessing potential risks to aquatic organisms. Results of the exposure assessment are provided in table 3

- 7.



### B. ATO H AZARD 

### C HARACTERIZATION FOR 

### E COLOGICAL ORGANISMS

The hazard information described in this section was evaluated for acceptability based on criteria established for aquatic toxicity testing within EPA’s OPPT ( US EPA, 2009 ) . The most reliable hazard data were obtained for ATO ( Sb 2 O 3 ) and antimony trichloride ( SbCl 3 )

.

The scientific literature wa s reviewed to identify laboratory animal studies that could be used to assess hazards to ecological organisms. Publications were critically evaluated based on the endpoint s used to assess toxicity, the amount of detail provided in each study , and adherence to specific test guidelines. Ultimately, the COC s identified for ecological organisms in water
, soil
, and sediment were based on the most robust ecotoxicity information available in the published literature (S ummarized in Table 3

- 3)

.

ACUTE TOXICITY TO AQUATIC ORGANISMS

EPA selected a cute aquatic toxicity studies for fish, invertebrates, and plants ; SbCl 3 was used as the test substance for all of these species, whereas Sb 2 O 3 was used in only one plant stud y (Table 3

- 3)

. The effect levels provided below are based on the measured antimony ion concentration s reported in the se studies

.

The a cute toxicity to fish species was evaluated using SbCl 3 with red sea bream ( P agrus major ) ( Takayanagi, 2001 ). A 96

- hr LC 50 of 6.9 mg/L was reported by the authors. Though this study was determined to be reliable, uncertainties regarding speciation and the specific test concentrations ( i.e.
, only a range of concentrations was provided in the report ) preclude its use for derivation of the COC.

3 See attached file titled “Supplemental E

- FAST2 Results - 250 day s per yr scenario for the TSCA Workplan Chemical Risk Assessment of ATO (External Review Draft). pdf ”
4 See attached file titled “Supplemental E

- FAST2 Results - 24 days per yr scenario for the TSCA Workplan Chemical Risk Assessment of ATO (External Review Draft). pdf ”DRAFT DO NOTE CITE OR QUOTE

Page 28 Table 3

- 3

. Aquatic toxicity data for Sb 2 O 3 and SbCl 3 .

Test O rganism Species Test Type Endpoint Antimony Compound Value Data Adequacy Reference

Fish P agrus major Acute 96

- hr LC 50 SbCl 3 6.9 mg Sb/L Inadequate Takayanagi (2001 ) Aquatic i nvertebrate Chlorohydra viridissima A cute 96

- hr LC 50 SbCl 3 1.77 mg Sb/L Adequate, used for COC derivation (acute) TAI (1990 )

Aquatic p lant Pseudo

kirchneriella subcapitata 72

- hr LC 50 (growth rate) SbCl 3 EC 50 > 36.6 mg/L NOEC = 2.11 mg Sb/L LOEC of 4.00 mg Sb/L GMATC = 2.91 mg Sb/L Adequate Heijerick and Vangheluwe (2004 )

Aquatic p lant P. subcapitata 72

- hr LC 50 (growth rate) Sb 2 O 3 NOEC = 0.396 mg Sb/L LOEC = 1.32 mg Sb/L GMATC = 0.723 mg Sb/L Inadequate LISEC (2001 )

Fish Pimephales promelas C hronic 30 -d ay (growth) SbCl 3 NOEC = 1.13 mg Sb/L LOEC = 2.31 mg Sb/L GMATC = 1.62 mg Sb/L Adequate, used for COC derivation (chronic) Kimball (1978 )

Fish P. promelas C hronic 30

- d ay (growth) Sb 2 O 3 NOEC >0.0075mg /L Adequate LeBlanc and Dean (1984 ) Aquatic i nvertebrate D aphnia
magna C hronic 21 -d ay (reproduction) SbCl 3 NOEC = 1.74 mg Sb/L LOEC = 3.13 mg Sb/L GMATC = 2.33 mg Sb/L Adequate Heijerick a nd Vangheluwe (2003b )a)

NOEC = no observed effect concentration LOEC = lowest

- observed

- effect concentrationDRAFT DO NOTE CITE OR QUOTE

Page 29 For aquatic invertebrates, a 96

- hr test was conducted with SbCl 3 in hydra ( Chlorohydra viridissima ) result ing in an LC 50 value of 1.77 mg/L ( TAI, 1990 ) . This value is used to determine an acute COC for aquatic invertebrates, as it is a reliable study conducted in a sensitive species ( EU RAR, 2008 ) . In addition, this study provided both nominal and measured concentrations for the trivalent form of antimony.

Two studies using an algal species ( Pseudokirchneriella subcapitata ) were conducted using either Sb 2 O 3 or SbCl 3 . Growth rate (E r C 50 ; effective concentration where in 50 percent of the tested organisms experienced a decline in growth rate) was determined to be the most sensitive endpoint, with the geometric mean of the maximum allowable toxicant concentration (GMATC) determined to be 2.91 and 0.723 mg/L for Sb 2 O 3 and SbCl 3 , respectively ( Heijerick and Vangheluwe, 2004 ; LISEC, 2001 ) . The LISEC (2001 ) study is considered unreliable because the E r C 50 value could not be determined due to uncertainties regarding the concentration response. For example, the limit concentration resulted in minimal inhibition (three percent) of the growth rate, which is considered to be the most sensitive endpoint ( EU RAR, 2008 ) . Though the data reported by Heijerick and Vangheluwe (2004 ) are reliable ( i.e.
, based on the Organi z ation for Economic Cooperation and Development (OECD) Guidelines for the Testing of Chemicals (Freshwater Alga and Cyanobacteria, Growth Inhibition Test) ) , the reported E r C 50 value (>36.6 mg/L) indicates that this species is not particularly sensitive to SbCl 3 .

CHRONIC TOXICITY TO AQUATIC ORGANISMS

Chronic toxicity studies using both Sb 2 O 3 and SbCl 3 are available , but only for fish and aquatic invertebrates (Table 3

- 3). No reliable chronic toxicity studies were available for aquatic plants; therefore, acute studies were considered for this endpoint.

In a 30

- day chronic toxicity study with SbCl 3 in fathead minnows ( Pimephales promelas ) , growth was determined to be the most sensitive endpoint ( Kimball, 1978 ) . The authors reported a GMATC value of 1.62 mg/L, which was used to calculate a chronic COC for this assessment. A second study that evaluated Sb 2 O 3 effects in P. promelas reported a no

- observed effect concentration (NOEC) > 0.0075 mg/L, based on growth as the most sensitive endpoint ( Le Blanc and Dean, 1984 ) . This study was not selected for calculating a chronic COC due to the lack of effects observed at the highest concentration tested. Heijerick and Vangheluwe (2003b ) conducted a 21

- day test with SbCl 3 in aquatic invertebra tes ( Daphnia magna ). Reproduction

was the most sensitive endpoint identified in this study, yield ing a GMATC value of 2.33 mg/L. Though this study was reliable, the data were not selected for derivation of a chronic COC because the GMATC for P. promelas indicates that of the species evaluated , fish are most sensitive.

AQUATIC COC DERIVATION

The acute COC for aquatic organisms was derived from the 96

- hr LC 50 of 1.77 mg/L obtained using SbCl 3 in the aquatic invertebrate, Chlorohydra viridissima . This value was divided by anDRAFT DO NOTE CITE OR QUOTE

Page 30 assessment factor (uncertainty factor) of five for invertebrate species to yield an acute COC of 0.354 mg/L (354 ppb) in accordance with OPPT guidance ( US EPA, 2009 ).

The chronic COC for aquatic organisms was derived from the 30

- day GMATC for growth (1.62 mg/L ) determined using SbCl 3 in fish ( P. promelas ) ( Kimball, 1978 ) . This value was divided by an assessment factor (uncertainty factor) of 10 for fish species in accord ance with OPPT guidance ( US EPA, 200 9 ) to yield a chronic COC of 0.162 mg/L (162 ppb).

The Kimball (1978 ) study was also used to determine a predicted no

- effect concentration ( PNEC ) of 0.113 mg/L in the EU risk assessment ( EU RAR, 2008 ); however, only the NOEC value (1.13 mg/L) was used. For hazard assessment purposes, the EU derives PNEC s by utilizing the lowest NOEC value and applying an assessment factor of 10 ( EU RAR, 2008 ; EU, 2003 )

. The EPA approach for determining a COC from a chronic study utilize s the GMATC value (if applicable) from the lowes t- observed

- effect concentration ( LOEC ) and the NOEC . EPA applied an assessment factor of 10 in accord ance with OPPT guidance ( US EPA, 2009 )

. The Environment Can ada/Health Canada (2010 ) risk assessment use d the same data provided in the European Union Risk Assessment Report ( EU RAR, 2008 ) and relie d on similar methods to calculate a PNEC of 0.113 mg/L

.

CHRONIC TOXICITY TO TERRESTRIAL SOIL INVERTEBRATES

EPA identified chronic toxicity studies for soil dwelling invertebrate s

. Several studies were available from secondary sources; however, only the study from Moser (2007 ) was considered reliable

. The study is described in the following excerpt taken from the EU RAR (2008 ):

“ Moser (2007 ) studied the toxicity of Sb to the springtail Folsomia candida (reproduction and m or tality) us in g aged (approximately 32 w ) Sb 2 O 3 - amended soil. Ten (10

- 12 d old) synchronized springtails were put onto 30 g moist soil in a glass vessel during a four

- week exposure. Five replicates were used for each test concentration and the measured test concentrations were 90, 322, 999, 2930 , and 1011 9 mg Sb/kg soil dw. Additionally, the springtails were also tested us in g uncontaminated field soil and an untreated artificial soil as control s , based on OECD 207. The positive control used on springtail reproduction was the herbicide Betosip (a.i. 159 g/L phenmedipham). At the end of the exposure period, the number of juveniles in each test vessel was counted after floating. The m ortality of the springtails was also recorded. At day 28, the pH

value and the moisture of the artificial s oil for each concentration in additional vessels without springtails were determined f or both mortality and reproduction, the highest effect observed was below 50% in any of the treatments. Consequently, LC 50 and EC 50 values could not be calculated
, but were estimated as >10,119 mg Sb/kg soil dw for each one of the endpoints. The NOEC reproduction was approximately 999 mg Sb/kg dw; the LOEC reproduction was approximately 2,930 mg Sb/kg dw. All reported values refer to measured concentrations. ”DRAFT DO NOTE CITE OR QUOTE

Page 31 The remaining studies were reviewed and evaluated by EPA, but were not used for COC derivation due to deficiencies ( or discrepancies ) in study design and uncertainties associated with inadequate or missing information are summarized in Table 3

- 4.

TERRESTRIAL SOIL COC DERIVATION

To determine the COC for soil invertebrates, the NOEC (999 mg Sb/kg dry weight [dw]) and LOEC (2,930 mg Sb/kg dw) for reproductive endpoints ( Moser, 2007 ) were used; the GMATC from these values wa s 1,710.9 mg Sb/kg dw. This was divided by an assessment factor 5 of 10 to yield 171.09 mg Sb/kg dw for the chronic COC. Since no acute toxicity studies were identified that assess ed effects on soil

- dwelling organisms, EPA used the GMATC value obtained from the chronic study (1,710.9 mg Sb/kg dw) as the acute COC, in accordance with OPPT guidance, ( US EPA, 2009 ).

5 The ( US EPA, 2009 ) ecotoxicity assessment factors used to calculate concern concentrations for aquatic organisms will be used to calculate the concern concentrations for soil and sediment organisms for the purposes of this hazard assessment. While this document also refers to the assessment of discrete organic chemicals, it is also part of the guidance used in OPPT to use the same assessment factors for assessing hazard s associated with inorganic metals.DRAFT DO NOTE CITE OR QUOTE

Page 32 Table 3

- 4 . Soil T oxicity D ata for Antimony Compounds.

Test O rganism Species Test Type Endpoint Antimony Compound Value Data A dequacy Reference

Springtail Folsomia candida ISO 1126 7 Reproduction Sb 2 O 3 NOEC reproduction = 999 mg Sb/kg dw LOEC reproduction =2,930 mg Sb/kg dw Adequate, used for COC derivation Moser (2007 )

Earthworm Eisenia fetida ISO 1126 8-2 Adult s urvival/ j uvenile
p roduction Sb 2 (SO 4 ) 3 NOEC/LOEC adult survival = 617/697 mg Sb/kg NOEC/LOEC juvenile production = 60/86 mg Sb/kg Inadequate Simini et al. (2002 )

Enchytraeid Enchytraeus crypticus ISO 1638 7 Adult survival/ juvenile production Sb 2 (SO 4 ) 3 NOEC/LOEC adult survival = 384/538 mg Sb/kg NOEC/LOEC juvenile production = 100/140 mg Sb/kg Inadequate Kuperman et al. (2002 )

Springtail F. candida ISO 1126 7 Adult survival/ juvenile production Sb 2 (SO 4 ) 3 NOEC/LOEC adult survival = 100/126 mg Sb/kg NOEC/LOEC juvenile production = 100 /126 mg/kg Inadequate Phillips et al. (2002 )DRAFT DO NOTE CITE OR QUOTE

Page 33 SEDIMENT INVERTEBRATE TOXICITY

Toxicity to sediment organisms in freshwater systems has been investigated in three different species ( EU RAR, 2008 ) . The se test species included: (1) the bottom

- dwelling amphipod ( Hyalella azteca ), which is a surface deposit and filter feeder
, (2) the midge larvae ( Chironomus riparius ), which burrows and feeds in sediment and on detritus
, and (3) the oligochaete ( Lumbriculus variegatus ), which feeds in sediment and interstitial spaces below the water

sediment interface ( Heijerick and Vangheluwe, 2003a
, 2005 a, 2005b ) . A summary of the sediment toxicity studies is provided in Table 3

- 5.

Heijerick and Vangheluwe (2003a ) exposed amphipods ( H. azteca ) to SbCl 3 at five

co ncentrations (rang ing from 30.8 to 249 mg Sb/kg weight wet [ww]; 44 to 355 mg Sb/kg dw) in a sediment

- water system for 28 days. Each test concentration included 13 replicates with 10 amphipods each. Four replicates were used for the 28

- day growth and survival endpoints, and eight replicates were used t o evaluate effects on survival and reproduction on day 35 and 42 (including growth). The remaining replicate was used to measure the antimony concentration in sediment. After the initial exposure period, the amphipods were removed from the sediment and placed in sediment

- free chambers for another 14 days. Effects on

s urvival (day 28, 35, 42), growth (day 28, 42), and reproduction (number of offspring per female from day 28 to 42) were evaluated. Growth (weight and length) was identified as the most sensitive endpoint after 28 days of exposure, resulting in a NOEC of 87 mg Sb/kg ww (124 mg Sb/kg dw).

For the study with the oligochaete ( L

. variegatus ), Heijerick and Vangheluwe (2005a ) exposed adult animals to SbCl 3 in a sediment

- water system for 28 days. Effects on s urvival, reproduction, and growth were evaluated at the end of the exposure period. The study was performed using six exposure concentrations (23 to 445 mg Sb/kg ww; 33 to 636 mg Sb/kg dw)
, a control (<1.4 mg Sb/kg ww), and seven replicates per concentration. Six replicates were used
to evaluate effect s on survival, reproduction
, and growth after 28 days of exposure ; the remaining replicate was used to measure the antimony concentration in sediment

. Growth (weight) was determined to be the most sensitive endpoint, resulting in a NOEC of 78 mg Sb/kg

ww (112 mg Sb/kg dw).

Two

- day

- old midge larvae ( C

. riparius ) were exposed to a range of SbCl 3 concentrations in a sediment

- water system until the larvae tran sformed to the adult phase ( Heijerick and Vangheluwe, 2005b ). Larval mortality and growth, and emergence to midges were determined after 14 and 28 days of exposure. The study was performed with six concentrations (23 to 445 mg Sb/kg ww; 33 to 636 mg Sb/kg dw) and a control (<1.4 mg Sb/kg ww; <2.0 mg Sb/kg dw). Eleven replicates were included fo r each concentration, five of which were used to evaluate effects on survival and growth after 14 days of exposure. Another five were used to determine the ext ent of emergence after 28 days of exposure, and the remaining replicate was used to measure the antimony concentration in sediment

. G rowth (weight) was t he most sensitive endpoint , result ing in a NOEC of 78 mg Sb/kg ww (112 mg Sb/kg dw).DRAFT DO NOTE CITE OR QUOTE

Page 34 Table 3

- 5. Sediment Toxicity Data for Antimony Compounds.

Test Organism Species Test Type Endpoint Antimony Compound Value Data Adequacy Reference

Amphipod Hyalella
azteca 42

- day chronic sediment toxicity test Survival/growth/ reproduction SbCl 3 NOEC = 87 mg Sb/kg ww (124 mg Sb/kg dw) Adequate Heijerick and Vangheluwe (2003a )

Oligochaete Lumbriculus variegatus OECD “Bioaccumulation; Sediment test using benthic oligochaetes” and the EPA 600/R

- 99/064 Section 13, Test Method 100.3

“ Lumbriculus variegatus bioaccumulation test for sediments” Survival/growth/ reproduction SbCl 3 NOEC = 78 mg Sb/kg ww (112 m g Sb/kg dw) Adequate Heijerick and Vangheluwe (2005a )

Midge larvae Chironomus riparius OECD guideline 218 sediment

- water chironomid toxicity test using spiked sediment Survival/growth/ reproduction SbCl 3 NOEC = 78 mg Sb/kg ww (112 mg Sb/kg dw) Adequate Heijerick and Vangheluwe (2005b )DRAFT DO NOTE CITE OR QUOTE

Page 35 To determine the chronic COC for toxicity to i nvertebrates in freshwater sediment, the NOEC for the growth endpoint (78 mg Sb/kg ww) was used as 112 mg Sb/kg dw (based on a 70/100 calculated ww/dw ratio ). The effect levels reported in the Heijerick and Vangheluwe (2005a
, b ) studies on oligochaete and the midge larvae were divided by an assessment fact or 6 of 10 to yield 11.2 mg Sb/kg dw as the chronic COC. In the absence of a reliable acute toxicity study, the NOEC value obtained from the chronic study ( 112 mg Sb/kg dw ) was used for the acute COC. The dw value is used for comparison with the suspended sediment data obtained from the USGS

- NWIS samples ( collected as mg Sb/kg dw ).

The Heijerick and Vangheluwe (2005a
, b ) studies were also used in the EU risk assessment to de rive a PNEC value of 11.2 mg/kg dw ( EU RAR, 2008 ) ; however, even though a GMATC can be calculated, the EU derived a PNEC by utilizing the lowest NOEC value and applying an assessment factor of 10 ( EU RAR, 2008 ) . OPPT has not established an approach for determining a chronic COC for sediment based on a chronic study ; t herefore, in the absence of an established OPPT methodology, the E U approach will be used in combination with a 10

- fold assessment factor, i n accordance with OPPT guidance ( US EPA, 2009 )

.


### C. E NVIRONMENTAL 

### R ISK 

### C HARACTERIZATION

The goal of this environmental risk characterization is to evaluate potential risks to water and sediment

- dwelling organisms as a result of exposure to ATO. To this end, measured and modeled environmental concentrations are compared to the hazard benchm arks (COCs) identified for these compartments. EPA’s environmental exposure assessment included a characterization of the available environmental monitoring data and modeling of industry

reported water releases

.

SUMMARY OF EXCEEDANCES AS INDICATED BY ENVIRONMENT A L MONITORING DATA

EPA’s exposure assessment utilized a robust environmental monitoring dataset. Out of a total of 8,5 00 environmental monitoring samples for water, sediment, and soil, only a small number exceeded the respective COCs for these media. The environmental monitoring data are summarized below and presented in Table 3

- 6.

A total of 5,49 3 water samples were evaluated. Of the 3,64 3 water samples obtained from the USGS

- NWIS database from 1972 to 2012, only five samples (~0. 4 percen t) exceeded the chronic COC for water (162 μg/L); these samples were collected between 1987 and 1988. Of the 1,850 water samples obtained from the STORET database between 2002 and 2010, seven samples (~0.4 percent) exceeded the chronic COC for water.

6 The US EPA (2009 ) ecotoxicity assessment factors used to calculate concern concentrations for aquatic organisms will be used to calculate the concern concentrations for soil and sediment organisms for purposes of this hazard assessment. While this document also refers to the assessment of discrete organic chemicals, it is also part of the guidance used in OPPT to use the same assessment factors for assessing hazard associated with inorganic metals

.DRAFT DO NOTE CITE OR QUOTE

Page 36 A total of 2,985 sediment samples were evaluated in the exposure assessment ; 1, 753 sediment samples collected from 1987 to 2011 were obtained from the USGS

- NWIS database. Of these, only 14 samples (~0. 9 percent) exceeded the chronic COC for sediment (11.2 m g/kg dw) and all were obtained before 2005. There were 1,222 sediment samples obtained from the STORET database from 2002 to 2010; six (~ 0. 5 percent) were determined to be above the chronic COC for sediment (11.2 mg/kg dw). No exceedance of the COC for w ater

- , sediment

- , or soil

dwelling organisms was identified within the last three years ( i.e ., from 2009 to 2012) for any of the TRI facilities evaluated in this assessment

.
Only 32 soil samples were obtained from the USGS

- NWIS database between 2005 and 2010; none were above the acute COC for soil (171.09 mg/kg dw) ; n o soil samples were available in the STORET database. Figure 3

- 1 shows locations where water or sediment samples obtained from the USGS

- NWIS and STORET data subsets exceeded the respective COCs for water - or sediment

- dwelling organisms. Figure 3

- 2 shows all of the locations evaluated and determined to be lower than the identified hazard benchmarks ( i.e., COCs)

. In summary, the environmental monitoring data collected from two national datasets (USGS

NWIS and STORET) indicated minimal concern for ecological risks from ATO use in halogenated flame retardants. L ess than 0.01 percent of the environmental monitoring samples collec ted in the 10 states covered under the scope of this assessment showed antimony concentrations above the COC for water or sediment, and all were collected more than three years ago (Fig ure 3- 1) . The average antimony concentration for the 3,64 3 water sampl es obtained from the USGS

- NWIS dataset was 4 μg/L , which is roughly 40 times lower than the COCs for aquatic organisms. In addition, there were 1,7 5 3 sediment samples in the USGS

- NWIS dataset with an average antimony concentration of 1.3 mg/kg dw, which i s approximately 10 times lower than the chronic COC for sediment -d welling organisms (Figure 3- 2)

.DRAFT DO NOTE CITE OR QUOTE

Page 37 Table 3 -6. Summary of All USGS

- NWIS and STORET data for Samples A bove Concentrations of Concern per M edia T ype
. a

Sample Type Parameter Code Date of Sample Value Above

COC Station Name Latitude Longitude Data Quality Description (USGS

NWIS data only) b

Water

– USGS

- NWIS Chronic COC for water = 162 μg/L Acute COC for water = 354 μg/L

3,64 3 9 total water samples; Only 5 were above COC ; No samples above COC in 2009 or later 0 1097 : Antimony, water, filtered, μg/L 26

- Aug

- 87 350 c μg/L Red R i v er n ear Quanah, TX 34.4 1312 91

- 99.7345385 Historical data
17

- Feb

- 88 350 c μg/L Red R iver n ea r Quanah, TX 34.41312 91

- 99.7345385 Historical data
25

- Aug

- 87 350 c μg/L Buck Creek at Loco, TX 34.70 2835 89

- 100. 1881691 Historical data
25

- Aug

- 87 350 c μg/L Buck Creek near Childress, TX 34.6 1172 738

- 100. 1109 427 Historical data

26

- Aug

- 87 350 c μg/L Salt F or k Red R iv er n ea r Wellington, TX 4.95755294

- 100. 220949 Historical data

Water – STORET Chronic COC for water = 162 μg/L Acute COC = 354 μg/L 1, 850 total water samples : 7 Samples rep orted above COC for water (162 μg/L) 10

- Dec

- 08 7, 600 μg/L Grays Creek , TN 35. 200600

- 89.681500 NA
26

- Oct

- 04 2, 000 μg/L Beech River , TN 36.605000

- 88.1188 00 NA
3- Nov

- 04 2, 000 μg/L Muddy Creek

- Unnamed Tributary , TN 35.095833

- 88.499444 NA

18

- Dec

- 02 1, 000 μg/L Alexander Creek, TN 36.52060 0

- 82.71780 0 NA
26

- Oct

- 04 1, 000 μg/L Big Sandy River
, TN 36. 232500

- 88.1003 00 NA
23

- Sep

- 04 1, 000 μg/L Buffalo River , TN 35.457800

- 87.775800 NA
12

- Oct

- 04 1 , 000 μg/L Clinch River , TN 36.569400

- 83.04 1700 NA
S ediment – USGS Chronic COC = 11.2 mg/kg Acute COC = 112 mg/kg 1,753 total sediment samples;

14 samples above COC for sediment ( dw ) ; No 2981 6: Antimony, suspended sediment, total digestion, dw 12

- Jan

- 88 90 mg/kg Kentucky River at Lock 4 at Frankfort, KY 38. 2017388

- 84.881617 1 Historical data

20

- Dec

- 89 42 mg/kg Kentucky River at Lock 2 at Lockport, KY 38.43895654

- 84.9632844 Historical data

0 1098 26

- Oct

- 05 12 mg/kg Lake Mohawk 1.3 mi les upstream of dam near Sparta , NJ 41.01761 11

- 74.6578056 Presumed

s atisfactory

34795 26

- Oct

- 05 12 mg/kg Lake Mohawk 1.3 mi les upstream of dam near 41.0 1761 11

- 74.6578056 Presumed

s atisfactoryDRAFT DO NOTE CITE OR QUOTE

Page 38 Table 3 -6. Summary of All USGS

- NWIS and STORET data for Samples A bove Concentrations of Concern per M edia T ype
. a

Sample Type Parameter Code Date of Sample Value Above

COC Station Name Latitude Longitude Data Quality Description (USGS

NWIS data only) b samples above COC in last 3 years Sparta , NJ
2981 6 14

- Apr

- 95 26 mg/kg Mohawk River at Cohoes
, NY 42.78535559

- 73.7076188 Historical data

2981 6 14

- Apr

- 95 23 mg/kg Mohawk River at Cohoes
, NY 42.78535559

- 73.7076188 Historical data

2981 6 17

- Sep

- 96 13 mg/kg St. Lawrence River at Cornwall Ontario near Massena , NY 45.006 1599

- 74.7949099 Historical data

2981 6 26

- Sep

- 96 20 mg/kg Rio Grande bl Falcon Dam, TX 26.557 2768

- 99.1683666 Historical data

2981 6 21

- Mar

- 96 14 mg/kg Rio Grande bl Falcon Dam, TX 26.557 2768

- 99.1683666 Historical data

2981 6 01

- May

- 96 18 mg/kg Rio Grande at Foster Rh

n ea r Langtry, TX 29.78075694

- 101.7559523 Historical data

34795 19

- Dec

- 05 20 mg/kg ZK

- 58

- 27

- 7 at Avery Deer Spring, TX 30.5075

- 97.749 1667 Reviewed and

a ccepted
2981 6 29

- May

- 96 18 mg/kg Rio Grande at El Paso , TX 31.80 2884 88

- 06.5408218 Historical data
2981 6 23

- Oct

- 96 16 mg/kg Rio Grande at El Paso , TX 31.80 2884 88

- 06.5408218 Historical data
34795 30

- Aug

- 03 18 mg/kg AF Plant 4 Ofl No. 4 n ea r Bomber R oa d, F or t Worth, TX 32.776 1944 4

- 97.4535833 Reviewed and

a ccepted

Sediment – STORET Chronic = 11.2 mg/kg (dw) Acute = 112 mg/kg (dw)

1,222 total sediment samples; 21

- Sept

0404 88.1 mg/kg West/East Creeks, NJ 39. 176000

- 74.900000 NA

24

- Sept

0404 57.2 mg/kg Great Sound, NJ 39.009000

- 74.81500 0 NA

28

- Sept

0404 35.8 mg/kg Great Egg Harbor, NJ 39.366000

- 74.71600 0 NA

8

- Aug

- 00 5 20.5 mg/kg Upper NY/NJ Harbor, NY 40.699000

- 74.0 2000 0 NADRAFT DO NOTE CITE OR QUOTE

Page 39 Table 3 -6. Summary of All USGS

- NWIS and STORET data for Samples A bove Concentrations of Concern per M edia T ype
. a

Sample Type Parameter Code Date of Sample Value Above

COC Station Name Latitude Longitude Data Quality Description (USGS

NWIS data only) b

6 samples above COC for sediment ( dw ) 3- Oct

- 00 6 13.7 mg/kg Raritan Bay, NJ 40.494000

- 74.2880 00 NA
3

- Oct

- 0606 11.8 mg/kg Raritan River, NJ 40.503000

- 74. 2920 00 NA

a USGS

- NWIS dataset collected was filtered using the following selection criteria: 1 st Data selection factor = Site type name (Site_tp_In). All types listed; those in blue bold are the ones selected: Atmosphere; Coastal - 18 water samples; Collector or Ranney

type well; Ditch; Estuary - only sediment samples; Hyporheic

- zone well; Lake, Res ervoir, Impoundment - 279 water samples; Outfall - 27 water samples; Pavement; Soil hole; Spring - 174 water samples; Storm sewer; Stream - 3,151 water samples; Test hole not completed as well; Tunnel, shaft, or mine; Unsaturated zone; Wastewater land appl ication; Water

- distribution system; Water

- use establishment; and Well. 2 nd Data selection factor = Media Name (Medium_nm). All types listed; those in blue bold are the ones selected: Animal tissue; Artificial; Bottom material; Core material; Effluent - 1 water sample; Groundwater; Interstitial water; Soil; Surface water - 3,648 water samples; Suspended sediment; and Wet deposition. Data selection factor for Water samples : medium_nm = Surface water and Effluent. Data selection factor for Sediment samples : Medium Name - Bottom Material, Effluent, Surface water (as reported in mg/kg), Suspended sediment, and wet deposition. Data selection factor for Soil samples : medium_nm = Soil. b The USGS

- NWIS dataset contains a field named ‘dqui_nm
, ’ which is defined as ‘Data Quality Descriptions

. ’ STORET does not have this field; therefore
, NA ( Not applicable ) is denoted in this column.

c 1⁄2 detection/reported value.DRAFT DO NOTE CITE OR QUOTE

Page 40 Figure 3

- 1. Locations of USGS

- NWIS and STORET Monitoring Samples with Concentrations Greater Than COCs

.DRAFT DO NOTE CITE OR QUOTE

Page 41 Figure 3

- 2. Locations of USGS

- NWIS and STORET Monitoring Samples with Concentrations Less Than COCs

.DRAFT DO NOTE CITE OR QUOTE

Page 42 SUMMARY OF TRI MODELING RESULTS

ATO surface water concentrations were predicted using the E

- FAST2 screening

- level model of water releases reported by selected TRI facilities in 2010. Because TRI does not indicate the number of days associated with reported releases, two scenarios were d eveloped ( i.e.
, assuming either 24 or 250 days of release) to provide a range of predicted water concentrations for comparison with hazard benchmarks id entified for aquatic organisms.

The Probabilistic Dilutio n Model (PDM), a module of E

- FAST2 that predicts the number of days a stream concentration will exceed a COC value, was used for both release scenarios. The estimated 7Q10 concentrations (μg/L) and the predicted days of exceedance of the COC for aquatic o rganisms (as predicted by the PDM model), are shown in Table 3 -7. The COC exceedance days refers to the total number of release days in a given year that the chronic COC would be exceeded using the surface water concentrations predicted using the E

- FAST2 model

.DRAFT DO NOTE CITE OR QUOTE

Page 43 Table 3 -7. Summary of E

- FAST2 Results for Facilities Reporting TRI Water Releases

. Facility name NPDES Code EFAST Results (250 days of release) EFAST Results (24 days of release)

7Q10 Concentration (ppb) Days of Exceedance 7Q10 Concentration (ppb) Days of Exceedance

Eastman Kodak Co TN Eastman Co Div, Kingsport, TN, 37662 TN0002640 1.15 0 11.99 0

Guilford East Plant, Kenansville, NC, 28349 NC0002305 62.07 0 674.14 3

A uriga Polymers Inc. Spartanburg Facility
, Spartanburg, 29307 SC0002798 2.29 0 23.97 0

Sabic Innovative Plastics US LLC, Selkirk, NY, 12158

- 0145 NY0007072 0.08 0 0.81 0

Sabic Innovative Plastics Mt. Vernon, LLC, Mount Vernon, IN, 47620 IN0002101 0.02 0 0.25 0

Sage Automotive Interiors Abbeville Plant, Abbeville, SC, 29620 SC0000353 29.86 1 311.55 6

P erformance F ibers O perations I nc. S alisbury P lant , Salisbury, NC, 2814 7 NC0004944 2.83 0 30.04 0DRAFT DO NOTE CITE OR QUOTE

Page 44 Table 3 -7. Summary of E

- FAST2 Results for Facilities Reporting TRI Water Releases

. Facility name NPDES Code EFAST Results (250 days of release) EFAST Results (24 days of release)

7Q10 Concentration (ppb) Days of Exceedance 7Q10 Concentration (ppb) Days of Exceedance

Dupont Teijin Films, Chester, VA, 23836 VA0003077 0.07 0 0.78 0

Haywood Co, Brownsville, TN, 380121797 TN0041939 0.03 0 0.33 0

Bayshore Industrial La Porte, TX, 77571 b TX0022799 2.54 b NA 25.36 b NA

C ovalence Adhesives , Franklin, KY, 42134 KY0074659 0.69 0 7.61 0

General Cable Industries Inc., Marion, IN,
46953 IN0002372 0.19 0 2.14 0

Borealis Compounds Inc., Port Murray, NJ,
07865 NJ0028657 0.09 0 0.96 0

Cerro Wire LLC, Hartselle, AL 35640 AL0054674 0.08 0 0.92 0

a These screening - level estimates are based on a range of days of release, which may not represent actual releases and environmental concentrations at these f acilities. b Dilution factor of 1 used as standard practice for sites that discharge into lakes, bays, estuaries and oceans. This facility releases to Galveston Bay. NPDES = National Pollution Discharge Elimination System NA = Not ApplicableDRAFT DO NOTE CITE OR QUOTE

Page 45 The model ing results obtained for the TRI facilities evaluated in this assessment indicate negligible risks for aquatic organisms. N o exceedance of the COC w as predicted using the 250 days/yr release scenario ; s tream concentrations generated by the model were from 2 to 100,000 times lower tha n the COCs identified for aquatic organisms

. T he 24 days/yr release scenario also predicted stream concentrations that were well below the acute and chronic COCs for aquatic organisms for most sites ; however, o ne exceedance of the acute COC was predicted ( i.e., predicted stream concentration = 647 μg/L ). The predicted stream water concentration for another site also exceeded the chronic COC for aquatic species ( i.e., 311 μg/L); however, the PDM only predicted three and six days of exceedance, respectivel y for these sites which is less than the time required to trigger a concern for chronic risk ( 20 days ) based on EPA guidance ( US EPA 2009 ).

UNCERTAINTY AND DATA LIMITATIONS

The primary sources of uncertainty identified in this assessment are related to limitations in the available exposure and hazard data, the E

- FAST2 model, and the parameters that support them, as discussed below.

Limitations of the Exposure and Release Data The environmental fate and transport of antimony is complex, and is influenced by site

- specific conditions. For example, the surface environment is enriched in a ntimony as a result of natural events ( e.g. , volcanic eruptions, hydrothermal vents, etc .) and various forms can exist ( e.g. , free, complexed to metal ligands, or incorporated in suspended particles), which may affect bioavailability to living organisms. In addition, the stability of antimony complexes in aqueous environments may be influenced by t he acidity, oxygenation and content of the receiving
water. Because site

- specific environmental parameters that can impact bioavailability vary significantly, it is difficult to extrapolate to other sites or geographic regions within the US.

The USGS

- NWIS database is one of the most robust environmental monitoring databases in the US; however, information needed for accurate data interpretation is not always available. In some instances, proprietary information may be withheld
, or specific details regarding analytical t echniques may be unclear
, or not reported. As a result, there are uncertainties in the reported data that may be difficult to quantify with regard to their impact on exposure estimate s.

The quality of the data provided in the USGS

- NWIS and STORET datasets varies , and some of the information provided is non

- quantitative. While a large number of individual sampling results were obtained from these datasets , the monitoring studies used to collect the data were not specifically designed to evaluate ATO distribution across the US . These data represent a variety of discrete locations and time periods ; therefore it is unknown whether the data are representative of other locations in the US. This limitation does not, ho wever, diminish the overall findings reported in this assessment. The data show very few instances ( i.e., less thanDRAFT DO NOTE CITE OR QUOTE

Page 46 0.01 percent ) where measured or predicted antimony levels in the ambient environment exceed the identified hazard benchmark s ( COCs )

.

T he TRI database is a comprehensive source of environmental release data for the US; however, it has many inherent uncertainties. TRI information is self

- reported by facilities (that are subject to minimum reporting thresholds) and may use approximations
, based on mass balances and emission factors
, rather than actual emissions or release data. As such, t he use of TRI data to estimate environmental exposures is constrained by a number of uncertainties including: the heterogeneity of processes and releas es among facilities grouped within a given
sector ; assumptions made during the identification of facilities using sector definitions provided in the TRI database ; lack of information regarding the distribution of specific antimonial compounds reported wit hin the selected TRI category of ‘ antimony compounds ’ ; and fluctuations in the level of production and associated environmental releases reported from year to year. Uncertainty may also arise from omissions in the TRI reporting data, such as sectors that are not required to report, facilities that fall below the reporting threshold, or facilities for which forms simply are not filed. While these limitations are important, their impact on estimating exposure potential may be less than that associated with the conservative assumptions that were made regarding environmental releases. ATO is reported in TRI under the broader category of ‘ antimony compounds ’, which covers all chemicals that contain antimony . As s uch
, EPA expects the actual releases of ATO to be lower than th os e reported in TRI

.

E- FAST2 Model Uncertainties By definition, models represent simplifications of real world conditions. They can not include all of the parameters necessary to capture the complexity of the natural environment. T he major limitation s associated with use of the E

- FAST2 model relate to the assumptions made regarding missing information required as model input
, including specific information regarding the pattern of release s or the type of antimony compounds reflected in reported TRI releases. It is important to note h owever, that these limitations are un likely to change the c onclusions of this
assessment , because they are based on a series of conservative assumptions that, in general, overestimate exposures to ecological organisms.

Limitations of the Hazard Data The l aboratory studies used to identify hazard benchmarks ( i.e., COCs) for ecological organisms varied in t erms of t he analytical methods used to measure antimony concentrations and the form of antimony used to assess toxicity. For example, the aquatic COCs were derived from studies using SbCl 3 , whereas the data used to assess ecological exposure s are for ‘ antimony
compou nds ’

. Minimal impacts on risk findings determined for water - and sediment

- dwelling organisms are expected since both compounds produce comparable amounts of antimony ion upon dissolution. The potential risk to soil

- dwelling organisms was shown to be low ; however, this conclusion is drawn from a limited set of data that may not be representative of the US.DRAFT DO NOTE CITE OR QUOTE

Page 47 CONCLUSIONS

The purpose of th is assessment was to evaluate the potential ecological risks of concern that may be associated with ATO use as a synergist in halogenated flame retardants . To this end, hazard benchmarks, or COCs , were compared to the measured antimony concentrations in water, soil, and sediment
, and to the predicted ATO surface water concentrations based on modeled releases reported in the 2010 TRI

. Despite the data limitations and uncertainties described above, negligible risk s of concern are expected for ecological organisms based on the following considerations:

• Use of ‘antimony compounds’ as a surrogate for ATO and modeled exposure estimates based on the conservative assumption of total releases (during the 2010 TRI reporting cycle) occurring over a 24

- day period are likely to overestimate exposure potential

.

• Use of sensitive ecological sp ecies to identify the most conservative COCs showed very few instances where measured or predicted values exceed the COCs for water

- , sediment

- , or soil

- dwelling organisms.

• Measured antimony concentrations from environmental monitoring samples collected within the last three years did not exceed any of the calculated COCs.

This assessment provides important insights regarding the potential risks of concern to ecological organisms associated with ATO use in halogenated flame retardants. Monitored and mod eled values of ATO are assumed to represent reasonable estimates of environmental
exposures

.DRAFT DO NOTE CITE OR QUOTE

Page 48 

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. US Geological Survey. http://minerals.usgs.gov/minerals/pubs/commodity/antimony/antimmyb05.pdf . Accessed November 7, 2012.

USGS (2011). 2010 Minerals yearbook. Antimony [advanced release]

. US Geological Survey. http://minerals.usgs.gov/minerals/pubs/commodity/antimony/myb1

- 2010

- antim.pdf . Accessed November 7, 2012.

USGS (2012a). Antimony. Mineral commodity summary

. US Geological Survey. http://minerals.usgs.gov/minerals/pubs/commodity/antimony/mcs

- 2012

- antim.pdf . Accessed November 7, 2012.

USGS (2012b). Water q uality samples for the nation. National Water Information System: Web Interface. http://nwis.waterdata.usgs.gov/usa/nwis/qwdata

. Watt, W. D. (1983). Chronic inhalation toxicity of antimony trioxide: Validation of the threshold limit value

. Wayne State University, Detroit, Michigan. (as cited in EU RAR, 2008).

Weidenfeller (2005). Final report of the distiness testing of powdery substances (Antimony trioxide) on behalf of EBRC Consulting Gmbh

. GF- no. 00 009 05. (as cited in EU RAR, 2008).

Weil, E., and Levchik, S. (2009). Flame retardants for plastics and textiles: Practical applications . Hanser Publications, Munich, Germany.

WHO (2003). Antimony in drinking

- water. Background document for development of WHO guidelines for Drinking

- water Quality

. World Health Organization. www.who.int/water_sanitation_health/dwq/chemicals/antimony.pdf . Accessed November 2, 20 12.DRAFT DO NOTE CITE OR QUOTE

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# Appendi **x**DRAFT DO NOTE CITE OR QUOTE

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## Appendix **A :**  **Human Health Hazard Summary**

Toxicokinetics Precise quantitative information regarding antimony absorption, distribution
, and retention in humans is lacking; however, increased levels of antimony have been reported in blood and urine obtained from workers following ATO inhalation exposure, indicating that trivalent antimony may be absorbed from the lungs and excreted in the urine ( Bailly et al. , 1991 )

. A renal elimination half

- life of four days was estimated in 21 employees of a starter battery manufacturing plant who were exposed to ATO via inhalation ( Kentner et al. , 1995 ).

S ystemic absorption following inhalation exposure is mainly influenced by chemical form, particle size
, and solubility. In general, large particles ( ≥ 2.5 μm) tend to deposit in the upper airway and are cleared more rapidly ( via mucociliary transport) than smaller particles that can deposit in the lower lung, where clearance times depend more on solubility ( i.e. , less soluble particles will be cleared more slowly) ( Brain et al. , 1994 ).

Antimony may be retained in the lungs for long periods following inhalation exposure. Lung retention times measured in seven male workers accidentally exposed to radiolabeled aerosols of ATO ( 125 Sb) showed that m ost of the radiolabel ed material was confined to the lungs, with negligible amounts detected in other parts of the body. The estimated e limination half

- li fe for antimony varied significantly, rang ing from 600 to 1,100 days in non

- smokers and 1,700 to 3,700 days in smokers, suggesting that ATO lung clearance may be negatively impacted by smoking ( Garg et al. , 2003 )

. D eceased smelter and refinery workers exposed to ATO primarily via inhalation, exhibited elevated lung concentrations when compared to non

- occupationally exposed individuals ( Gerhardsson et al. , 1982 ) ; however, antimony concentration s measured in other organs ( e.g. , liver and kidney ) were comparable, suggest ing either a short biological half

life or limited systemic distribution for antimony in these tissues.

Laboratory animal data indicate low systemic absorption of ATO when administered via the oral
route ( Felicetti et al. , 1974 ; De Bie and Salmon

- te Rietstap, 2005 )

. Therapeutic use of antimonial compounds for the treatment of parasitic diseases has also demonstrated poor systemic bioavailability following oral exposure in humans ( WHO, 2003 ). Based on results reported by the International Commission on Radiological Protection, limited systemic absorption (~1 % ) may be assumed when estimating ATO upt ake from the gastrointestinal tract ( as cited in EU RAR, 2008 ) ; dermal absorption (0.26 % ) is negligible ( Roper and Stupart, 2006 )

. It has been suggested that a portion of systemic absorption observed following inhalation
exposure is due to the clearance of large particles ( via mucociliary transport ) and subsequent uptake into the gastrointestinal tract ( Brain et al. , 1994 ) . Using the Multiple Path Particle Deposition model and predicted deposition patterns for inhaled ATO particles ( 4 μm), the total systemic absorption (reflecting combined uptake in the lung s and gastrointestinal tract) was estimated at approximately 7% ( as cited in EU RAR, 2008 )

.
Once taken up into the systemic circulation, trivalent antimony accumulates in red blood cells and is distributed p rimarily to liver, spleen
, and bone ( Casals, 1972 ). It has been suggested thatDRAFT DO NOTE CITE OR QUOTE

Page 59 t his pattern of distribution may reflect clear ance from circulation via phagocytic macrophages located in the se organs which effectively sequester non

- endogenous molecules ( Sarin, 2010 )

.
Acute Toxicity The a vailable laboratory animal data indicate low acute toxicity via oral, dermal
, and inhalation
routes ( as cited in EU RAR, 2008 ):

• oral LD 50 >20,000 mg/kg

- bw (rats)

• dermal L D 50 >8,300 mg/kg

- bw (rabbits)

• inhalation LC 50 (4

- hour) >5,200 mg/m 3 (rats)

Irritation No adverse skin reactions have been reported in laboratory animal s ; however, workers have reported skin irritation following dermal exposure to ATO under conditions of intense heat and heavy sweating ( NIOSH, 1978 ; Potkonjak and Pavlovich, 1983 )

. It has been suggested that ATO may induce skin rashes ( i.e
., antimony spots) as a result of physical obstruction of the sweat ducts

. Lung and eye irritation have also been noted with occupational exposure, but no causal relationship has been established. Although ATO is not classified as an irritant under the Registration, Evaluation, Authorization and Restriction of Chemicals
, workers are encouraged to avoid excessive contact via use of personal protective equipment.

Subchronic Toxicity R epeated inhalation exposure has been shown to cause respiratory irritation in rodents ( Groth et al. , 1986 ; Newton et al. , 1994 ; Potkonjak and Vishnjich, 1983 ) . Although detailed occupational exposure data are lacking in the US, early case reports of adverse pulmonary effects (inflammation, pneumoconiosis, emphysema) and decreased lung function ( Potkonjak and Vishnjich, 1983 ) indicate a potential for adverse respiratory effects in humans following repeated inhalation exposure

. In addition, gastrointestinal disorders (vomiting, diarrhea)
, fatigue, dizziness, and headaches have been reported in workers heavily exposed to smelter fumes ( NIOS H, 1978 ) . It is important to note however, that working conditions have improved significantly over the p ast 30 years ; a permissible exposure limit of 0.5 mg/m3 has been set to protect this population.

Carcinogenicity T he International Agency for Rese arch on Cancer (IARC) concluded that “there is sufficient evidence for the carcinogenicity of ATO in experimental animals" ( IARC, 1989 ) based on one published
, and one unpublished report of increased lung tumors in female rats following ATO inhalation exposure ( Groth et al. , 1986 ; Watt, 1983 )

. A nother chronic inhalation study has since been published that found no increased cancer incidence following ATO inhalation
exposure in rats ( Newton et al. , 1994 ).

The proliferation of alveolar macrophages is generally regarded as a normal physiological response to the deposition of poorly solubl e particulates in the lung; however, in rats repeatedly exposed at high levels, macrophage clearance is impaired, resulting in “lungDRAFT DO NOTE CITE OR QUOTE

Page 60 overload ” . This condition is characterized by macrophage infiltration, chronic interstitial inflammation, metaplasia, and the subsequent development of lung tumors

. Although the cascade of effects caused by pulmonary overload are unlikely to be relevant for humans, the rat is assumed to be an appropriate model for both ne oplastic and non

- neoplastic responses to poorly soluble particulates ( Mauderly, 1997 ) . Because the responsiveness of the rat model to

non

- genotoxic agents ( under conditions of lung overload ) is dependent upon chronic active inflammation and cell proliferation, no lung cancer hazard is anticipated for humans exposed to A TO at lower , environmentally relevant concentrations
, where chronic active inflammation and cell proliferation are not present ( ILSI, 2000 ).

IARC concluded that “there is inadequate evidence for the carcinogenicity of ATO in humans” ( IARC, 1989 )

. Since this evaluation, two epidemiological studies of increased cancer incidence in smelt er workers have been publ ished.

A mortality study conducted in 1, 014 male workers employed in an antimony smelter plant between 1937 and 1971 showed a significant excess in mortality from lung cancer , ischemic heart disease and non

- malignant respiratory disease ; however, th e authors acknowledge d that the observed increase in cancer mortality may be influenced by co

- exposure to arsenic ( Schnorr et al. , 1995 ).

A survey of antimony smelter workers employed before 1961 showed a significant increase in lung cancer mortality (12 expected vs. 5.3 observed, p = 0.016) , with a minimum latency period of a pproximately 20 years between the first exposure and death from lung cancer ( Jo nes, 1994 ). No correlation between the length of employment at the smelter and cancer mortality was found . In addition, no excess cancer mortality was found in the cohort recruited after 1960

. This study is limited by the lack of an appropriate control population, and confounding factors such as cigarette smoking and co

- exposure to polycyclic aromatic hydrocarbons, arsenic
, and sulfur. As such, the increased cancer mortality observed in the ea rlier cohort could not be attributed to a specific agent.

While it is clear that ATO inhalation exposure can impair pulmonary clearance in rats ( Newton et al. , 1994 ) , it is important to note that a nimal studies tend to employ significantly higher concentration s and longer durations of exposure than would generally be expected for humans. Although the available information is limited, t here is no evidence of carcinogenicity via the oral
route ( Schroeder et al. 1968 ; Schr oeder et al.
, 1970 ).

Mutagenicity The available in vitro data for ATO

- induced mutagenicity is mixed. ATO was not mutagenic when tested in Salmonella typhimurium strains TA98, TA100, TA 1535 , and TA1537 or E

scherichia coli WP2P and WP2P uvrA with or without metabolic activation; however, ATO induced chromosomal aberrations in cultured human leukocytes and lymphocytes ( Elliott et al.
, 1998 ) . No mutagenic potential was observed in mouse lymphoma cells ( Paton and Allison, 1972 ) , but weak induction levels (~ two

- fold above background) were reported in a sister chromatid exchange assay using V79 cells in vitro ( Kuroda et al. , 1991 ) . Conflicting results haveDRAFT DO NOTE CITE OR QUOTE

Page 61 also been obtained for ATO

- induced mutagenicity in vivo . Mice gavaged with aqueous ATO at 400, 668 , and 1,000 mg/kg

- bw/ day for up to 21 days were positive for chromosomal aberrations, but not clastogenic effects ( Gurnani et al. , 1992 ) . A mouse micronucleus test conducted with ATO showed no clastogenic effects following one high dose (5,000 mg/kg

- bw ) or repeated exposure at 400, 668, or 1,000 mg/kg

- bw/ day for 7, 14, or 21 days ( Elliott et al.
, 1998 ) . Negative results were also reported for micronuclei induction in rats following oral exposure at 250, 500 , or 1, 000 mg/kg

- bw/ day for 21 days ( Kirkland et al. , 2007 )

.
Limited evidence of mutagenic potential has been demonstrated for ATO; however, a number of technical experts have independently concluded that ATO is unlikely to be mutagenic in vivo ( European Food Safety Authority, 2004 ; Environment Canada/Health Canada, 2010 ; Tweats et al. , 2007a , b )

. Since a possible local genotoxic effect of ATO would only be relevant under exposure conditions that also produce lung overload, minimal concerns are i ndicated for humans ( EU RAR, 2008 ).

Reproductive Toxicity A relative paucity of data exists regarding the potential for ATO

- induced reproductive or developmental effects; however, a weight

- of

- evidence approach may be used to address these endpoints. Toxicokinetic considerations, together with the absence of effects on reproductive organs in repeated

- dose studies suggest low co ncern for reproductive effects.

Limited information is available from a Russian report on ATO ( Belyaeva, 1967 ), which indicated adverse reproductive effects in rats ( e.g. , ovarian cysts, uterine metaplasia, decreased fertility) following inhalation exposure at 250 mg/m 3 for 4 hours / day during a two

- month period. These study authors also reported adverse reproductive outcomes (spontaneous abortions, premature births, gynecologic problems) in women following exposure to metallic d usts (of antimony, ATO, and antimony pentasulfide) at unspecified concentrations while working in a metallurgical plant. T he reported results are largely inconclusive and inadequate for risk assessment due to inadequate or missing information regarding study design ( e.g. , lack of information on experimental conditions, controls, and purity of test substance) and exposure conditions

.

N o testicular effects were observed in male rats or mice following repeated gavage exposure to ATO at doses ≥ 1, 000 mg/kg -b w/day ( Gurnani et al. , 1 992 ; Omura et al. , 2002 ) . In addition, oral exposure to ATO during a 90

- day feeding in rats study showed no effects on male reproductive organs up to the highest dose tested ( 1,686 mg/kg

- bw/day; Hext et al. , 1999 )

. Gerber et al. (1982 ) used a readily soluble, radiolabeled compound, antimony trichloride ( 125 SbCl 3 ), to determine the extent of uptake in pregnant mice following dietary exposure to a mixture of antimony chloride and arsenic throughout pregnancy. Minimal absorption (~7 % ) was observed in treated dams, with limited distribution to reproductive organs (~0 .1 to 0.2 % in ovaries and uteri). This finding is supported by a nother prenatal developmental toxicity study, in pregnant ewes dosed orally throughout gestation with antimony tartrate (a highly soluble form of antimony expected to exhibit higher absorpti on as compared to ATO ) at 2 mg/kg

- bw/ day showed no adverse maternal or developmental effects ( James et al. , 1966 ).DRAFT DO NOTE CITE OR QUOTE

Page 62 Developmental Toxicity In a prenatal developmental toxicity study, female Sprague

- Dawley rats (26/dose) were exposed to ATO via (nose

- only) inhalation at 0, 2.6, 4.4 , and 6.3 mg /m 3 ( mass median aerodynamic diameter [ MMAD ] = 1.59 to 1.82 μm) for 6 hours/day from the day of fertilization through day 19 of gestation. Significant increases in lung weights and an accumulation of ATO in erythrocytes were observed in all treated dams as compared to controls. In addition, histological examination revealed an accumulation of pigmented alveolar macrophages, and discrete areas of acute inflammation and hyperplasia in the lungs. An i ncrea se in post

implantation loss (3.4, 3.6, 3.5
, and 7.1 % in the 0, 2.6, 4.4
, and 6.3 mg/m 3 groups; p = 0.11) w as observed at the highest concentration tested ; however, these changes were not statistically significant. No developmental effects were reported ; the no

- observed

- adverse

- effect concentration ( NOAEC ) for developmental toxicity was determined to be > 6.3 mg/m 3 . A NOAEC for maternal toxicity could not be established, as increased lung weight was observed at all levels of exposure ( Schroeder, 2003 ).

Synopsis Inhalation of airborne du sts is the primary concern for ATO exposure in occupational settings, whereas the general population is primarily exposed to low levels of ATO in food and water.

Chemical speciation and route of exposure are major determinants of antimony toxicity in humans. Generally speaking, pentavalent antimony is less toxic than the trivalent species ; however, most antimony compounds are oxidized to ATO upon release into the environment, and the available evidence suggests that over time, further oxidation to the pentavalent form may occur under aerobic conditions ( EU RAR, 2008 )

. In addition, quantitative studies indicate that minimal amounts of ATO are released from flame

- retarded consumer products ( CPSC, 2006 , 2012 ; Thomas and Stevens, 2005 )

.
The general population is exposed mainly via ingestion of food and water, whereas inhalation and dermal contact are more common in occupational settings. Irritation at the point of contact ( e.g. , dermatitis, lung inflammation, pneumoconiosis) has been reported in workers following chronic inhalatio n exposure ( NIOSH, 1978 ) ; however, a permissible exposure limit of 0.5 mg/m3 has been set to protect this population. ATO produces minimal systemic toxicity when a dministered via oral, dermal
, or inhalation routes due to poor systemic absorption
, which effectively limits bioavailability. Because food and water are the primary sources of general population exposure, and the pentavalent ( i.e. , less toxic) form of antimony predominates in these media, significant health risks are not expected at concentrations to which individuals may be exposed in the environment ( ATSDR, 1992 ) . This conclus ion is supported by previous risk assessments for ATO in Europe and Canada ( EU RAR, 2 008 ; Environment Canada/Health Canada, 2010 ).DRAFT DO NOTE CITE OR QUOTE

Page 63 PREVIOUS ASSESSMENTS

Environment Canada/Health Canada : Screening Assessment for the Challenge – Antimony Trioxide ( Environment Canada/Health Canada, 2010 ) ( http://www.ec.gc.ca/ese

- ees/9889ABB5

- 3396

- 435B

- 8428

- F270074EA2A7/batch9_1309

- 64

- 4_en.pdf )

In Canada, ATO is listed on the Domestic Substances List and is characterized as “inherently toxic to aquatics
, ” but did not meet the full categorization criteria and was not recommended for further assessment. In this assessment
, it was concluded:

“The margins between upper

- bounding estimates of exposure to antimony trioxide from environmental media (based on antimony) and from use of household items and levels associated with effects in experimental animals are considered to be adequately protectiv e to account for uncertainties in the health effects and exposure databases. On the basis of the adequacy of the margins between conservative estimates of exposure to antimony trioxide and critical effect levels in experimental animals, it is concluded that antimony trioxide is not entering the environment in a quantity or concentration or under conditions that constitute or may constitute a danger in Canada to human life or health.”

EU RAR – Diantimony Trioxide ( CASRN 1309

- 64

- 4) ( EU RAR, 2008 ) ( http://esis.jrc.ec.europa.eu/doc/risk_assessment/REPORT/datreport415.pdf )

In Europe, ATO is registered under REACH regulations; the European Commission classifies and labels ATO as “H351: suspected of causing cancer by inhalation ; ” therefore , “ a need for limiting the risks” was identified for workers.

The assessment of human health and environmental risks concluded:

“Overall results of the risk assessment for surface water, waste water treatment plants, terrestrial compartment, atmosphere, secondary poisoning, marine water, marine sediment, secondary poisoning in the marine environment: There is at present no need for further information and/or testing and no need for risk reduction measures beyond those which are being applied already

. ”

OECD Assess ment for Antimony Trioxide ( OECD, 2008 ) ( http://webnet.oecd.org/Hpv/UI/handler.axd?id=13e93c97

- 6605

- 4eac

- 961f

- 8af23cc6ad32 )

Environment:

“ This chemical is currently of low priority for further work.”DRAFT DO NOTE CITE OR QUOTE

Page 64 Human Health :

“Despite the poor quality of the available acute oral and dermal toxicity studies with diantimony trioxide in laboratory animals, diantimony trioxide is considered to be of low acute inhalation, oral and dermal toxicity. The chemical possesses properties indicating a hazard for human health (skin irritation, lung toxicity and lung carcinogenicity after repeated exposure). Member countries are invited to perform an exposure assessment for workers and if then indicated
, a risk assessment. As all studies on chronic toxicity/carcinogenicity deviate from the OECD guideline ...and because of other critical shortcomings in the data set on chronic toxicity/carcinogenicity, the US NTP (National Toxicology Program) has initiated 2

- year inhalation toxicology and carcinogenicity studies on diantimony trioxide in rats and mice.” ( http://ntp.niehs.nih.gov/?objectid=BCD52E6A

- 123F

- 7908

- 7BD5298A5D912AF9 )

Antimony in Drinking Water: Background D ocument for D evelopment of W orld Health Organization (W HO ) Guidelines for Drinking

- water Quality ( WHO, 2003 ) ( http://www.who.int/water_sanitation_health/dwq/chemicals/antimony.pdf )

“The WHO guideline for antimony in drinking water was quadrupled from 5 ppb to 20 ppb in 2003 after the incorporation of information obtained from an updated literature review.”