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Appendix of the Screening Assessment Report on

Hexabromocyclododecane

Chemical Abstracts Service Registry Number
3194-55-6

Environment Canada
Health Canada

November 2011


Table of Contents

Appendix C: Derivation of Predicted Exposure Concentrations (PECs) for Pelagic and Benthic Organisms Using a Fugacity Level III Box Model

A Level III fugacity (steady-state) box model based on the Level IV multispecies model described by Cahill et al. (2003) was applied for estimating aquatic exposure to hexabromocyclododecane (HBCD) in the pelagic and benthic compartments. An important feature of the Cahill et al. model is its ability to model the fate of transformation products in addition to that of the parent chemical. For HBCD, degradation to 1,5,9-cyclododecatriene (CDT) is considered an important fate process and this degradation product was included in the model as an additional species. CDT was not included in the risk quotient analysis for HBCD but is considered with respect to the overall persistence of the parent substance.

Figure C-1 provides a conceptual overview of the fugacity model. The model is a mass balance system consisting of 10 downstream boxes each with water and sediment compartments. For modelling purposes, the river is assumed to be a straight channel of uniform and rectangular cross-section with little or no vegetation present in the watercourse or along the banks. Release from the outfall is considered to be continuous from a steady vertical point source.

Figure C-1. Conceptual overview of the fugacity box model used to estimate water and sediment concentrations of HBCD - Downstream Advection and Sediment Interaction: 1) HBCD Source 2) Mass loading in 3) Downstream box 1 4) Advection in 5) Downstream box 2 6) Mass loading and Advection in 7) Downstream box 3 (separated compartments: water and sediment) a. In water: HBCD transform to CDT by transformation b. In sediment: HBCD transform to CDT by transformation and burial is advected by advection c. Resuspension / Diffusion and Deposition / Diffusion occurs between both compartments (water and sediment) 8) Advection out 9) Downstream box 4 10) Advection out 11) Downstream box 5 12) Advection out

Figure C-1. Conceptual overview of the fugacity box model used to estimate water and sediment concentrations of HBCD

For each box, the fugacity (f) of both HBCD and the potentially persistent degradation product, CDT, is modeled in each compartment (water, sediment). Fugacity, in units of Pascal (Pa) represents the “partial pressure” of a chemical species in a particular medium and is analogous to concentration, C (mol/m3), normalized to the relative affinity of the chemical for a particular medium (also known as the “fugacity capacity”, Z [mol/m3.Pa]). Thus, f = C/Z (Mackay 1991).

Aside from mass loading (which is a known discharge rate [mol/h]), the mass transport associated with each process (mol/h) is represented as the product of a fugacity rate coefficient (D, in units of mol/h.Pa) and f (Pa) for other compartments/species (for input processes), or of the modeled compartment/species (for output processes). Transformation of HBCD to CDT is included in the reaction terms. A detailed review of equations for this model is available (Environment Canada 2011).

The main assumptions of the model:

  1. chemical release to water only
  2. volatilization or air/water intermedia transport is negligible
  3. surface water consists of pure water, suspended sediment and biota phases
  4. bottom sediment consists of pure water and sediment solids phases
  5. first order reaction processes
  6. complete instantaneous mixing within boxes
  7. equilibrium between phases (pure water, sediment solids and biota) within a particular compartment

Model Parameters

The parameter inputs for the model include chemical properties (e.g., log Kow, Koc, degradation rates), substance release rates, receiving river conditions (e.g., river discharge and flow rates), and generic environmental parameters (e.g., organic carbon content of sediments and sediment deposition rates). Environmental parameters were chosen to represent rivers of southern Ontario based on parameters from ChemCan (Webster et al. 2004), the Cahill et al. (2003) model and plausible physical characteristics for similar river systems (considering values summarized in Chapra 1997 and Gobas et al. 1998). For this assessment, the model extended downstream 5000 m, split into 10 boxes. The length of the first and last boxes was set at 100 m each, and the length of the middle 8 boxes was set at 600 m each.

Loading Estimates and Model Scenarios

Loading estimates for the model were determined using quantities reported in the section 71 notice (Environment Canada 2001), default emission factors recommended by OECD (2004a) and default emission periods recommended in the European Communities Technical Guidance Document (TGD; European Communities 2003). Based on information provided in response to the section 71 notice, annual import volumes for the year 2000 were in the range of 100 000 to 1 000 000 kg. Furthermore, it was estimated that annual HBCD use at an individual facility in Canada would range from 10 000 kg/year to 100000kg/year. Two release scenario groups were developed to represent the types of HBCD-related activities most likely to be taking place in Canada: raw materials handling (Scenario Group 1), and compounding (Scenario Group 2). The OECD (2004a) defines raw materials handling as the handling of raw materials from their arrival on site to their addition to polymers, including manual handling of bags and sacks, conveyer belts and pneumatic or pumped transfer from bulk storage vessels. Compounding is then the process by which additives such as HBCD are incorporated into materials (e.g., plastics) during polymer production and includes processing and final conversion (OECD 2004a). The two activities of raw materials handling and compounding were separated in order to estimate the predicted incremental risk from each activity. HBCD is not produced in Canada and it is likely that any facility involved in compounding would also need to be involved with raw materials handling. For these facilities, the predicted incremental risks from raw materials handling and compounding would be additive.

Scenario Group 1 applied an emission factor of 0.6% based on OECD (2004a) and emission periods of 200 days for usage of 100 000 kg/year and 60 days for usage of 10 000 kg/year. For each usage rate, three possible levels of sewage treatment were applied (none, primary, and secondary) with removal rates estimated using EPIWIN (2000). The combination of two usage rates and three potential levels of sewage treatment yielded six possible emission scenarios for raw materials handling (Scenarios 1a–1f). Scenario Group 2 applied an emission factor of 0.055% based on OECD (2004a) and the same emission periods and levels of sewage treatment as Scenario Group 1, again resulting in six possible emission scenarios for compounding (Scenarios 2a–2f). Note that the OECD and TGD emission parameters were established by means of expert judgement and tend to the worst-case situation.

All release scenarios were assumed to describe industrial activities at a generic facility located in southern Ontario. Generic scenarios were employed to provide estimated release quantities in the absence of site-specific information. The generic facility was situated in southern Ontario as this region is associated with substantial industrial activity and might therefore be expected to have processing and production plants that utilize HBCD. The river dimension characteristics for these scenarios have been chosen to represent an average “medium-sized” river for the industrialized Lake Erie/lowland region of southern Ontario (i.e., the average of the middle 33% of rivers located in this region, based on Environment Canada’s Hydat database). The river discharge rate was based on the 25th percentile discharge rate for these rivers.

The release scenarios were entered into the fugacity box model and the results obtained were used to estimate potential water column exposure concentrations for pelagic organisms. For each scenario, the dissolved concentration of HBCD predicted to occur in the first 100 m from the point of discharge, termed Cmax, was considered to represent a reasonable and conservative exposure concentration in the river and was selected as the predicted environmental concentration (PEC). This concentration is equivalent to that which would result from instantaneous complete mixing of the substance in the first 100 m following discharge to the river.

The major characteristics and model input parameters for each scenario are summarized in Table C-1.

Model Results and Risk Analysis

Prior to calculation of risk quotients for the benthic and pelagic compartments, the scenarios and model-predicted concentrations were evaluated for their degree of “realism” with respect to expected actual HBCD release conditions in Canada. Upon review, it was judged that direct release of HBCD to watercourses without primary or secondary sewage treatment would not occur under normal operations of processing facilities. Based on these considerations, the scenarios with no sewage treatment (i.e., “none”) were excluded from the risk characterization (i.e., risk quotients were not calculated).

Pelagic Organisms

Table C-2 summarizes the risk quotient results obtained for pelagic organisms under the retained scenarios. Risk quotients ranged from 0.071 to 3.75 for an annual usage quantity per facility of 10 000 kg/yr and from 0.179 to 10.7 for a use quantity of 100 000 kg/yr. Predicted dissolved water concentrations of HBCD exceeded the predicted no-effect concentration (PNEC) for all raw materials handling scenarios (Scenario Group 1), except for low-volume (10 000 kg/yr) facilities utilizing secondary wastewater treatment. For the compounding scenarios (Scenario Group 2), predicted dissolved water concentrations of HBCD were below the PNEC for all scenarios except for high-volume (100 000 kg/yr) facilities using primary treatment.

Based on the risk quotient results, it is concluded that concentrations of HBCD in surface waters resulting from activities associated with raw materials handling and compounding have the potential to cause adverse effects in populations of pelagic organisms in Canada. Application of secondary treatment processes to wastestreams originating from HBCD processing facilities greatly reduces the potential for risk; however, predicted exposure values still exceed those of minimum effects levels for scenarios associated with large production quantities (e.g., 100 000 kg/yr) and/or use of primary wastewater treatment. It should be noted that although HBCD concentrations are predicted to decrease with distance, the potential distance of impact downstream (i.e., distance with risk quotients greater than 1) is expected to be significant (> 5000 m).

Benthic Organisms

Table C-3 summarizes the risk quotient results obtained for benthic organisms under each retained scenario. Results for benthic organisms generally paralleled those for pelagic organisms. Risk quotients ranged from 0.051 to 2.37 for an annual usage quantity per facility of 10 000 kg/yr and from 0.152 to 7.11 for a use quantity of 100 000 kg/yr. Predicted bulk sediment concentrations of HBCD exceeded the PNEC for scenarios associated with large-volume raw materials handling (Scenarios 1b and 1c) and smaller­volume raw materials handling with only primary wastewater treatment (Scenario 1e). Predicted bulk sediment concentrations of HBCD were less than the PNEC for all compounding scenarios (Scenario Group 2), suggesting that current volume estimates for this activity should not result in bulk sediment concentrations that exceed minimum effects levels in organisms. It should be noted that although HBCD concentrations are predicted to decrease with distance, the potential distance of impact downstream (i.e., distance with risk quotients greater than 1) is expected to be significant (> 5000 m).

Table C-1. HBCD emission rates, river characteristics and release for fugacity modelling release scenarios[1]

Industrial ActivityQuantity used at facility (kg/yr)
100 000100 000100 00010 00010 00010 000100 000100 000100 00010 00010 00010 000
Raw materials handling scenariosCompounding scenarios
1a1b1c1d1e1f2a2b2c2d2e2f
Emission factor (%)[2]0.60.60.60.60.60.60.0550.0550.0550.0550.0550.055
Emission days[3]200200200606060200200200606060
Quantity released from facility (kg/day)3331110.2750.2750.2750.0920.0920.092
Wastewater treatment typeNone[4][5]NoneNoneNone
Treatment removal rate (%)[6]05790057900579005790
Quantity of HBCD released to river (kg/day)31.280.310.430.10.280.120.0280.0920.0390.0092
River discharge (m3/s)[7]0.850.850.850.850.850.850.850.850.850.850.850.85
Mean flow depth (m)[8]0.330.330.330.330.330.330.330.330.330.330.330.33
River velocity (m/s)[8]0.310.310.310.310.310.310.310.310.310.310.310.31
River width (m)[8]8.58.58.58.58.58.58.58.58.58.58.58.5
[1] Environment Canada 2001
[2] OECD 2004a
[3] European Communities 2003
[4] Primary wastewater treatment
[5] Secondary wastewater treatment
[6] From STPWIN (EPIWIN 2000)
[7] Discharge estimates were made considering Southern Ontario streamflow data from the HYDAT streamflow database (National Water Data Archive, Environment Canada), and generally represent the 25th percentile of observed discharge rates.
[8] Channel geometry and hydraulic parameters were estimated using equations derived specifically for southern Ontario (Boivin 2005).

Table C-2. Model output and risk quotient analysis for pelagic organisms

Industrial ActivityQuantity used at facility (kg/yr)
100 000100 000100 00010 00010 00010 000100 000100 000100 00010 00010 00010 000
Raw materials handling scenariosCompounding scenarios
1a1b1c1d1e1f2a2b2c2d2e2f
Wastewater treatment typeNone[1][2]NoneNoneNone
PNEC (mg/L)5.6 ×10-45.6 ×10-45.6 ×10-45.6 ×10-45.6 ×10-45.6 ×10-45.6 ×10-45.6 ×10-45.6 ×10-45.6 ×10-45.6 ×10-45.6 ×10-4
Maximum concentration (Cmax, mg/L)[3]0.0150.0060.0010.00490.00210.00050.00130.00060.00010.000450.000190.00004
Concentration 5 km downstream from discharge (C5000, mg/L)[4]0.0100.0040.0010.00340.00150.00030.00090.00040.00010.000320.000130.00003
Maximum risk quotient (Qmax= Cmax/PNEC)NA[5]10.71.79NA[5]3.750.893NA[5]1.070.179NA[5]0.3390.071
Distance (m) with Q > 1NA[5]> 5000> 5000NA[5]> 5000NA[6]NA[5]> 5000NA[6]NA[5]NA[6]NA[6]
[1] Primary wastewater treatment
[2] Secondary wastewater treatment
[3] Cmax represents the dissolved HBCD concentration in the first 100 m of river downstream of the emission point.
[4] C5000 represents the dissolved HBCD concentration at a distance 4900–5000 m downstream of the emission point.
[5] Risk quotient not calculated because the “no treatment” scenarios were considered unrealistic.
[6] Not applicable as the predicted exposure concentration was less than the estimated no effect level.

Table C-3. Model output and risk quotient analysis for benthic organisms

Industrial ActivityQuantity used at facility (kg/yr)
100 000100 000100 00010 00010 00010 000100 000100 000100 00010 00010 00010 000
Raw materials handling scenariosCompounding scenarios
1a1b1c1d1e1f2a2b2c2d2e2f
Wastewater treatment typeNone[1][2]NoneNoneNone
PNEC (mg/kg dw of sediment)6.56.56.56.56.56.56.56.56.56.56.56.5
Maximum concentration (Cmax, mg/kg)[3]108.246.210.836.115.43.69.924.240.993.311.410.33
Concentration 5 km downstream from discharge (C5000, mg/kg)[4]76.732.87.725.610.92.67.033.010.702.341.000.23
Maximum risk quotient (Qmax= Cmax/PNEC)NA[5]7.111.67NA[5]2.370.553NA[5]0.6520.152NA[5]0.2170.051
Distance (m) with Q > 1NA[5]> 5000> 5000NA[5]> 5000NA[6]NA[5]NA[6]NA[6]NA[5]NA[6]NA[6]
[1] Primary wastewater treatment
[2] Secondary wastewater treatment
[3] Cmax represents the sediment HBCD concentration in the first 100 m of river downstream of the emission point.
[4] C5000 represents the sediment HBCD concentration at a distance 4900–5000 m downstream of the emission point.
[5] Risk quotient not calculated because the “no treatment” scenarios were considered unrealistic.
[6] Not applicable as the predicted exposure concentration was less than the estimated no effect level.

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Appendix D: Robust Study Summary Forms for Key HBCD Studies

Robust Study Summary - Persistence

ItemYesNo
Reference: CMABFRIP. 1996. Hexabromocyclododecane (HBCD): Closed bottle test. Wildlife International Ltd. Project No. 439E-102. Easton (MD): Wildlife International Ltd., November 11, 1996.
Test Substance (CAS RN and name): 3194-55-6, Cyclododecane, 1,2,5,6,9,10-hexabromo- (hexabromocyclododecane)
Chemical composition of the substance (including purity, by-products)X 
Method
ReferencesX 
OECD, EU, national, or other standard method?X 
Justification of the method/protocol if a non-standard method was used  
* GLP (good laboratory practice)X 
Test design / conditions
Study type (photodegradation, hydrolysis, biodegradation, other –specify, donot assess): Biodegradation
Test type (aerobic or anaerobic – specify, do not assess): Aerobic  
Test medium (air, water, soil, sediment – specify, do not assess): activated sludge  
Is information on stability of the substance in the media of concern reported?X 
Controls (positive or negative): Negative and Positive (Reference)X 
Number of replicates (including controls)X 
TemperatureX 
Duration of the experimentX 
For photodegradation only  
Light source (specify):  
Light spectrum and relative intensity based on sunlight intensity:  
For hydrolysis only  
Measured concentrations reported?  
Basic water properties (pH, hardness, etc.)  
For biodegradation only  
Ready or inherent biodegradation (specify): ReadyX 
Inoculum (concentration and source):X 
Results
Endpoints: Average oxygen uptake in controls, reference and treatments used to calculate biochemical oxygen demand (BOD) and percent degradation at each sampling interval. No degradation of the test substance was observed over the 28–day test period.
Information on breakdown products (donot assess this item): No  
Overall score: 11/11 = 100 %
EC reliability code: 1
Reliability category (high, satisfactory, low): High
Comments:

Robust Study Summary - Persistence

ItemYesNo
Reference: ACCBFRIP. 2003b. Evaluation of aerobic and anaerobic transformation of hexabromocyclododecane in aquatic sediment systems. Environmental Chemistry Research Laboratory Project Study ID 021081. Midland (MI): The Dow Chemical Company March 5, 2003.
Test Substance (CAS RN and name): 3194-55-6, Cyclododecane, 1,2,5,6,9,10-hexabromo- (hexabromocyclododecane)
Chemical composition of the substance (including purity, by-products)X 
Method
ReferencesX 
OECD, EU, national, or other standard method?X 
Justification of the method/protocol if a non-standard method was used  
* GLP (good laboratory practice)X 
Test design / conditions
Study type (photodegradation, hydrolysis, biodegradation, other –specify, donot assess): Biodegradation
Test type (aerobic or anaerobic – specify, do not assess): Aerobic and anaerobic  
Test medium (air, water, soil, sediment – specify, do not assess): Sediment  
Is information on stability of the substance in the media of concern reported?X 
Controls (positive or negative): NegativeX 
Number of replicates (including controls)X 
TemperatureX 
Duration of the experimentX 
For photodegradation only  
Light source (specify):  
Light spectrum and relative intensity based on sunlight intensity:  
For hydrolysis only  
Measured concentrations reported?  
Basic water properties (pH, hardness, etc.)  
For biodegradation only  
Ready or inherent biodegradation (specify): ReadyX 
Inoculum (concentration and source):X 
Results
Endpoints: Concentration of target substance at selected time intervals throughout exposure period used to calculate biotransformation half-lives. Biotransformation half-lives for HBCD determined as 11 and 32 days in the aerobic system and 1.1 and 1.5 days in the anaerobic system.
Information on breakdown products (do not assess this item): Yes - not detected  
Overall score: 11/11 = 100 %
EC reliability code: 1
Reliability category (high, satisfactory, low): High
Comments:

Robust Study Summary - Persistence

ItemYesNo
Reference: ACCBFRIP. 2003c. Evaluation of aerobic and anaerobic transformation of hexabromocyclododecane in soil. Environmental Chemistry Research Laboratory Project Study ID 021082. Midland (MI): The Dow Chemical Company March 5, 2003
Test Substance (CAS RN and name): 3194-55-6, Cyclododecane, 1,2,5,6,9,10-hexabromo- (hexabromocyclododecane)
Chemical composition of the substance (including purity, by-products)X 
Method
ReferencesX 
OECD, EU, national, or other standard method?X 
Justification of the method/protocol if a non-standard method was used  
* GLP (good laboratory practice)X 
Test design / conditions
Study type (photodegradation, hydrolysis, biodegradation, other –specify, donot assess): Biodegradation
Test type (aerobic or anaerobic – specify, do not assess): Aerobic and anaerobic  
Test medium (air, water, soil, sediment – specify, do notassess): Soil  
Is information on stability of the substance in the media of concern reported?X 
Controls (positive or negative): NegativeX 
Number of replicates (including controls)X 
TemperatureX 
Duration of the experimentX 
For photodegradation only  
Light source (specify):  
Light spectrum and relative intensity based on sunlight intensity:  
For hydrolysis only  
Measured concentrations reported?  
Basic water properties (pH, hardness, etc.)  
For biodegradation only  
Ready or inherent biodegradation (specify): ReadyX 
Inoculum (concentration and source):X 
Results
Endpoints: Concentration of target substance at selected time intervals throughout exposure period used to calculate biotransformation half-lives. Biotransformation half-lives for HBCD determined to be 63 and 6.9 days in the aerobic and anaerobic soils, respectively.
Information on breakdown products (donot assess this item): Yes - not detected  
Overall score: 11/11 = 100 %
EC reliability code: 1
Reliability category (high, satisfactory, low): High
Comments:

Robust Study Summary - Persistence

ItemYesNo
Reference: EBFRIP. 2004. Investigation of the biodegradation of [14C]hexabromocyclododecane in sludge, sediment, and soil. Toxicology and Environmental Research and Consulting Laboratory Project Study ID 031178. Midland (MI): The Dow Chemical Company November 30, 2004.
Test Substance (CAS RN and name): 3194-55-6, Cyclododecane, 1,2,5,6,9,10-hexabromo- (hexabromocyclododecane)
Chemical composition of the substance (including purity, by-products)X 
Method
ReferencesX 
OECD, EU, national, or other standard method?X 
Justification of the method/protocol if not a standard method was used  
* GLP (good laboratory practice)X 
Test design / conditions
Study type (photodegradation, hydrolysis, biodegradation, other –specify, donot assess): Biodegradation
Test type (aerobic or anaerobic – specify, do not assess): Aerobic and anaerobic  
Test medium (air, water, soil, sediment – specify, do not assess): Soil, sediment and sludge  
Is information on stability of the substance in the media of concern reported?X 
Controls (positive or negative): NegativeX 
Number of replicates (including controls)X 
TemperatureX 
Duration of the experimentX 
For photodegradation only  
Light source (specify):  
Light spectrum and relative intensity based on sunlight intensity:  
For hydrolysis only  
Measured concentrations reported?  
Basic water properties (pH, hardness, etc.)  
For biodegradation only  
Ready or inherent biodegradation (specify): ReadyX 
Inoculum (concentration and source):X 
Results
Endpoints: Numerical endpoints not determined as objective of study was to investigate pathways and major products formed during degradation.
Information on breakdown products (donot assess this item): Yes  
Overall score: 11/11 = 100 %
EC reliability code: 1
Reliability category (high, satisfactory, low): High
Comments:

Robust Study Summary - Persistence

ItemYesNo
Reference: Gerecke AC et al. 2006. Anaerobic degradation of brominated flame retardants in sewage sludge. Chemosphere 64:311–317.
Test Substance (CAS RN and name): 3194-55-6, Cyclododecane, 1,2,5,6,9,10-hexabromo- (hexabromocyclododecane)
Chemical composition of the substance (including purity, by-products): purity, not compositionX 
Method
References X
OECD, EU, national, or other standard method? X
Justification of the method/protocol if a non-standard method was usedX 
* GLP (good laboratory practice)not known 
Test design / conditions
Study type (photodegradation, hydrolysis, biodegradation, other –specify, donot assess): Biodegradation
Test type (aerobic or anaerobic – specify, do not assess): Anaerobic  
Test medium (air, water, soil, sediment – specify, do not assess): Sewage sludge  
Is information on stability of the substance in the media of concern reported? X
Controls (positive or negative): NegativeX 
Number of replicates (including controls): Not specifically but range (see Comments)X 
TemperatureX 
Duration of the experiment: Not specifically but upper limit (see Comments)X 
For photodegradation only  
Light source (specify):  
Light spectrum and relative intensity based on sunlight intensity:  
For hydrolysis only  
Measured concentrations reported?  
Basic water properties (pH, hardness, etc.)  
For biodegradation only  
Ready or inherent biodegradation (specify): ReadyX 
Inoculum (concentration and source):X 
Results
Endpoints: Degradation rate constants and half-lives for technical mixture and individual isomers. Only values for technical mixture reported. Rate constant for technical HBCD was 1.1 ± 0.3 d-1, corresponding to a half-life of 0.66 day.
Information on breakdown products (donot assess this item): No  
Overall score: 8/11 = 73 %
EC reliability code: 2
Reliability category (high, satisfactory, low): Satisfactory
Comments: Study is reported in a journal article and therefore not all details are included. Several brominated flame retardants were tested at the same time and the article reports overall methodology and results. While the method used is not standard, it appears to be scientifically sound and the study well conducted. Some important information (such as the number of replicates and exposure duration for the HBCD testing) is not provided.

Robust Study Summary - Bioaccumulation

ItemYesNo
Reference: Veith et al. 1979. Measuring and estimating the bioconcentration factor of chemicals in fish. J Fish Res Board Can 36:1040–1048.
Test Substance (CAS RN and name): 3194-55-6 (Hexabromocyclododecane)
* Chemical composition of the substance (including purity, by-products) X
Persistence/stability of test substance in test systemX 
Method
ReferencesX 
* OECD, EU, national, or other standard method?X 
Justification of the method/protocol if a non-standard method was used?n/a 
* GLP (good laboratory practice)n/a 
Test organisms (specify common and Latin names): fathead minnow (Pimephales promelas)
Latin or both Latin and common names reported?X 
Life cycle age / stage of test organismX 
Sexn/a 
Length and weight of test organisms X
Number of test organisms per replicateX 
Food type / feeding periods (acclimation/during test)X 
Test design / conditions
Test type (field, laboratory): laboratoryX 
Number of replicates (including controls) and concentrationsX 
* Measured concentrations reported? Mean measured exposure concentration reported; description of test methodology specifies that concentration was measured each weekdayX 
* Was the chemical concentration in the water below the chemical’s water solubility? Mean measured concentration 6 µg/L; water solubility 3.4-8.6 µg/LX 
* Experiment duration equal to or longer than the time required for the chemical concentration in the organism and water to reach steady state? Exposure time 32 days; steady state BCF calculated from 32-day exposure.X 
Exposure media conditions (temperature, pH, TOC, DOC, DO, other) reported? Temp., DO (saturation), hardness, alkalinity, pH of test water reportedX 
Photoperiod and light intensity: specifies that USEPA Methods (1975) usedX 
Stock and test solution preparation X
Information on emulsifiers used for poorly soluble / unstable substancesX 
Statistical methods usedX 
Was pH within 6–9 range? (do not assess this item)X 
Was temperature within 5–28°C range? (do not assess this item)X 
Results
Endpoints and values (BAF, BCF, or log Kow; do not assess this item): BCF = 18 100
BAF or BCF either as: 1) the ratio of chemical concentration in the organism and in water, or 2) the ratio of the chemical uptake and elimination rate constants (1 or 2 – specify; do not assess this item): 1
Whether BAF/BCF was derived from a tissue sample or whole organism (do not assess this item)?X 
Indication of whether average BAF/BCF was used (specify; do not assess this item)X 
Indication of whether max BAF/BCF was used (specify; do not assess this item) X
* BAF/BCF reported on a lipid-normalized basis, or was the lipid % reported?X 
Score: major items - 5/6; overall score: 17/20 = 85%
Reliability (Klimisch)code:1
Reliability category (high, satisfactory, low):High
Comments:

Robust Study Summary - Bioaccumulation

ItemYesNo
Reference: CMABFRIP. 2000. Hexabromocyclododecane (HBCD): A flow-through bioconcentration test with the rainbow trout (Oncorhychus mykiss). Easton (MD): Wildlife International Ltd. Project No. 439A-11.
Test Substance (CAS RN and name): 3194-55-6 (Hexabromocyclododecane)
* Chemical composition of the substance (including purity, by-products)X 
Persistence/stability of test substance in test systemX 
Method
ReferencesX 
* OECD, EU, national, or other standard method?X 
Justification of the method/protocol if a non-standard method was used?n/a 
* GLP (good laboratory practice)X 
Test organisms (specify common and Latin names): rainbow trout (Oncorhynchus mykiss)
Latin or both Latin and common names reported?X 
Life cycle age / stage of test organism: same source and year classX 
Sexn/a 
Length and weight of test organismsX 
Number of test organisms per replicateX 
Food type / feeding periods (acclimation/during test)X 
Test design / conditions
Test type (field, laboratory): laboratoryX 
Number of replicates (including controls) and concentrationsX 
* Measured concentrations reported?X 
* Was the chemical concentration in the water below the chemical’s water solubility?X 
* Experiment duration equal to or longer than the time required for the chemical concentration in the organism and water to reach steady state? Steady state achieved at highest test concentration, but not at lowest X
Exposure media conditions (temperature, pH, TOC, DOC, DO, other) reported? Temp., DO, pH, hardness, alkalinity, conductivity, TOC reportedX 
Photoperiod and light intensity:X 
Stock and test solution preparationX 
Information on emulsifiers used for poorly soluble / unstable substancesX 
Statistical methods usedX 
Was pH within 6–9 range? (donot assess this item)X 
Was temperature within 5–28°C range? (do not assess this item)X 
Results
Endpoints and values (BAF, BCF, or log Kow; do not assess this item): Day 35 BCF for 0.34 µg/L test concentration = 6531 (edible), 20 726 (nonedible), 13 085 (whole fish) NB. Steady-state not achieved at this concentration. Steady-state day 35 BCF at 3.4 µg/L test concentration = 4650 (edible), 12,866 (nonedible), 8974 (whole fish).
BAF or BCF either as: 1) the ratio of chemical concentration in the organism and in water, or 2) the ratio of the chemical uptake and elimination rate constants (1 or 2 – specify; do not assess this item): 1
Whether BAF/BCF was derived from a tissue sample or whole organism (donot assess this item)?X 
Indication of whether average BAF/BCF was used (specify; do not assess this item)X 
Indication of whether max BAF/BCF was used (specify; do notassess this item)X 
* BAF/BCF reported on a lipid-normalized basis, or was the lipid % reported?X 
Score: major items - 6/7; overall score: 20/21 = 95%
Reliability (Klimisch)code:1
Reliability category (high, satisfactory, low): High
Comments:

Robust Study Summary – Inherent toxicity

ItemYesNo
Reference: CMABFRIP. 1988. Hexabromocyclododecane (HBCD): A flow-through life-cycle toxicity test with the cladoceran (Daphnia magna). Easton (MD): Wildlife International Ltd. Project No.439A-108.
Test Substance (CAS RN and name): 3194-55-6 (Hexabromocyclododecane)
* Chemical composition of the substance (including purity, by-products)X 
Persistence/stability of test substance in test systemX 
Method
ReferencesX 
* OECD, EU, national, or other standard method?X 
Justification of the method/protocol if a non-standard method was used  
* GLP (good laboratory practice)X 
Test organisms (specify common and Latin names): Water flea (Daphnia magna)
Latin or both Latin and common names reported?X 
Life cycle age / stage of test organismX 
Sexn/a 
Length and weight of test organismsX 
Number of test organisms per replicateX 
Food type / feeding periods (acclimation/during test)X 
Test design / conditions
Test type – acute or chronic (specify; do notassess this item): chronic
Experiment type (laboratory or field) specified?X 
System type (static, semi-static, flow through)?X 
Negative or positive controls (specify)? Negative and solvent controlsX 
Number of replicates (including controls) and concentrationsX 
Exposure pathways (food, water, both)X 
Exposure durationX 
* Measured concentrations reported?X 
Exposure media conditions (temperature, pH, electrical conductivity, hardness, TOC, DOC, DO, major cations and anions; other)X 
Was pH within 6–9 range? (do not assess this item)X 
Was temperature within 5–28°C range? (do not assess this item)X 
Photoperiod and light intensityX 
Stock and test solution preparationX 
Use of emulgators/solubilizers (especially for poorly soluble / unstable substances)X 
Analytical monitoring intervalsX 
Statistical methods usedX 
Results
Toxicity values (LC50, EC50, or IC50 – specify; do not assess this item): 21-day LOEC (survival) > 11 µg/L, 21-day LOEC (reproduction) = 11 µg/L, 21-day LOEC (growth) = 5.6 µg/L, 21-day NOEC (overall study) = 3.1 µg/L
Other endpoints reported – e.g., BCF/BAF (specify; do not assess this item): 21-day MATC = 4.2 µg/L
* Was toxicity value below the chemical’s water solubility?X 
Other adverse effects (carcinogenicity, mutagenicity, etc. (do not assess this item) X
Score: major items – 5/5; overall score – 24/25 (96%)
EC Reliability code: 1
Reliability category (high, satisfactory, low): high
Comments: All major items reported “yes”; overall score 96%. Lowest toxicity value (5.6 µg/L) was slightly above the water solubility value of 3.4 µg/L (25°C) used by the study authors. However, a measured water solubility been reported by EBFRIP (2004a) in the range of 2.08 to 48.8 µg/L (20°C) for the individual diastereomers. Temperature 19.0–20.5°C. DO 7.2–8.8 mg/L. pH 8.1–8.4. Hardness 128–132 mg/L as CaCO3. Alkalinity 176–178 mg/L as CaCO3. Conductivity 310–320 µmhos/cm. Dimethylformamide solvent used. Good control performance, test concentrations well maintained throughout exposure period.

Robust Study Summary – Inherent toxicity

ItemYesNo
Reference: EBFRIP. 2004b. Hexabromocyclododecane (HBCD): A 72-hour toxicity test with the marine diatom (Skeletonema costatum). Easton (MD): Wildlife International Ltd. Project No. 439A-125.
Test Substance (CAS RN and name): 3194-55-6 (Hexabromocyclododecane)
* Chemical composition of the substance (including purity, by-products)X 
Persistence/stability of test substance in test systemX 
Method
ReferencesX 
* OECD, EU, national, or other standard method?X 
Justification of the method/protocol if a non-standard method was used  
* GLP (good laboratory practice)X 
Test organisms (specify common and Latin names): marine alga (Skeletonema costatum)
Latin or both Latin and common names reported?X 
Life cycle age / stage of test organismn/a 
Sexn/a 
Length and weight of test organismsn/a 
Number of test organisms per replicaten/a 
Food type / feeding periods (acclimation/during test)X 
Test design / conditions
Test type – acute or chronic (specify; do not assess this item): acute
Experiment type (laboratory or field) specified?X 
System type (static, semi-static, flow through)?X 
Negative or positive controls (specify)? Negative and media controlsX 
Number of replicates (including controls) and concentrationsX 
Exposure pathways (food, water, both)X 
Exposure durationX 
* Measured concentrations reported?X 
Exposure media conditions (temperature, pH, electrical conductivity, hardness, TOC, DOC, DO, major cations and anions; other)X 
Was pH within 6–9 range? (do not assess this item)X 
Was temperature within 5–28°C range? (do not assess this item)X 
Photoperiod and light intensityX 
Stock and test solution preparationX 
Use of emulgators/solubilizers (especially for poorly soluble / unstable substances)X 
Analytical monitoring intervalsX 
Statistical methods usedX 
Results
Toxicity values (LC50, EC50, or IC50 – specify; do not assess this item): 72-hour EC50(cell density, area under growth curve, growth rate) > 41.0 µg/L
Other endpoints reported - BCF/BAF, LOEC/NOEC (specify; do not assess this item): 72-hour NOEC (cell density, area under growth curve, growth rate) < 41.0 µg/L
* Was toxicity value below the chemical’s water solubility?X 
Other adverse effects (carcinogenicity, mutagenicity, etc. (do not assess this item) X
Score: major items – 5/5; overall score – 22/22 (100%)
EC reliability code: 1
Reliability category (high, satisfactory, low): high
Comments: All major items reported “yes”; overall score 100%. Selected test concentration (41.0 µg/L) is well above reported water solubility of 3.4 µg/L (25°C) for HBCD; however, a recent study by EBFRIP (2004a) measured solubility values of 2.08 to 48.8 µg/L at 20°C for the individual diastereomers. Therefore, although a toxic endpoint was not determined in the present study, consider the reported results to be meaningful within the context of a rangefinder test. Temperature 18.0–22.0°C. pH 7.9–8.4. Light intensity 4130–4660 lux. Control growth over the 3-day test period was 10–11x, and less than the OECD recommended 16x for test validity. However, consider that the response between controls and test solution was sufficiently delineated to indicate that inhibition was occurring in the test substance flasks.

Robust Study Summary – Inherent toxicity

ItemYesNo
Reference: Oetken et al. 2001. Validation of the preliminary EU-concept of assessing the impact of chemicals to organisms in sediment by using selected substances. UBA-FB 299 67 411. Dresden (DE): Institute of Hydrobiology, Dresden University of Technology
Test Substance (CAS RN and name): 3194-55-6 (Hexabromocyclododecane)
*Chemical composition of the substance (including purity, by-products) X
Persistence/stability of test substance in test systemX 
Method
ReferencesX 
* OECD, EU, national, or other standard method?X 
Justification of the method/protocol if a non -standard method was used  
* GLP (good laboratory practice)Not reported 
Test organisms (specify common and Latin names): Oligochaete (Lumbriculus variegatus)
Latin or both Latin and common names reported?X 
Life cycle age / stage of test organismX 
Sexn/a 
Length and weight of test organismsX 
Number of test organisms per replicateX 
Food type / feeding periods (acclimation/during test)X 
Test design / conditions
Test type – acute or chronic (specify, but do not assess this item): chronic
Experiment type (laboratory or field) specified?X 
System type (static, semi-static, flow through)?X 
Negative or positive controls (specify)? Negative and solvent controlsX 
Number of replicates (including controls) and concentrationsX 
Exposure pathways (food, water, both)X 
Exposure durationX 
* Measured concentrations reported?X 
Exposure media conditions (temperature, pH, electrical conductivity, hardness, TOC, DOC, DO, major cations and anions; other)X 
Was pH within 6–9 range? (do not assess this item)X 
Was temperature within 5–28°C range? (do not assess this item)X 
Photoperiod and light intensityn/a 
Stock and test solution preparationX 
Use of emulgators/solubilizers (especially for poorly soluble / unstable substances)X 
Analytical monitoring intervalsX 
Statistical methods usedX 
Results
Toxicity values (LC50, EC50, or IC50 - specify, do not assess this item): 28-day NOEC (no. of worms) = 3.25 mg/kg sediment dw; 28-day LOEC (no. of worms) = 29.25 mg/kg sediment dw; 28-day NOEC (large vs. small worms, mean biomass) = 29.25 mg/kg sediment dw; 28-day LOEC (large vs. small worms, mean biomass) = 311.35 mg/kg sediment dw.
Other endpoints reported - BCF/BAF (specify, do not assess this item):
* Was toxicity value below the chemical’s water solubility?n/a 
Other adverse effects (carcinogenicity, mutagenicity, etc. Do not assess this item) deformation (none)X 
Score: major items – 2/4; overall score – 20/22 (91%)
EC Reliability code: 2
Reliability category (high, satisfactory, low): satisfactory
Comments:An OECD guideline (218) was used with modifications and while GLP has not been specified in the report, the description of the methodology is consistent with GLP. Consider that the study has met basic scientific principles, and that all necessary data and documentation have been presented. Temperature 20°C. DO 7.52 ± 0.81 mg/L. pH 8.7 ± 0.15. Conductivity 1026 ± 199 µs/cm.

Robust Study Summary – Inherent toxicity

ItemYesNo
Reference: ACCBFRIP. 2003a. Effect of hexabromocyclododecane on the survival and reproduction of the earthworm, Eisenia fetida. Columbia (MI): ABC Laboratories Inc. Study No. 47222.
Test Substance (CAS RN and name): 3194-55-6 (Hexabromocyclododecane)
* Chemical composition of the substance (including purity, by-products)X 
Persistence/stability of test substance in test systemX 
Method
ReferencesX 
* OECD, EU, national, or other standard method?X 
Justification of the method/protocol if a non-standard method was used  
* GLP (good laboratory practice)X 
Test organisms (specify common and Latin names): Earthworm (Eisenia fetida)
Latin or both Latin and common names reported?X 
Life cycle age / stage of test organismX 
Sexn/a 
Length and weight of test organismsX 
Number of test organisms per replicateX 
Food type / feeding periods (acclimation/during test)X 
Test design / conditions
Test type – acute or chronic (specify, but do not assess this item): chronic
Experiment type (laboratory or field) specified?X 
System type (static, semi-static, flow through)?X 
Negative or positive controls (specify)? Negative controlX 
Number of replicates (including controls) and concentrationsX 
Exposure pathways (food, water, both)X 
Exposure durationX 
*Measured concentrations reported?X 
Exposure media conditions (temperature, pH, electrical conductivity, hardness, TOC, DOC, DO, major cations and anions; other)X 
Was pH within 6–9 range? (donot assess this item)X 
Was temperature within 5–28°C range? (do not assess this item)X 
Photoperiod and light intensityX 
Stock and test solution preparationX 
Use of emulgators/solubilizers (especially for poorly soluble / unstable substances)n/a 
Analytical monitoring intervalsX 
Statistical methods usedX 
Results
Toxicity values (LC50, EC50, or IC50 - specify, do not assess this item): 28-day EC10 and EC50 (survival) > 4190 mg/kg soil dw; 56-day EC10 (reproduction) = 21.6 mg/kg with 95% confidence limits of 0.000468 to 110 mg/kg; 56-day EC50(reproduction) = 771 mg/kg with 95% confidence limits of 225 to 4900 mg/kg
Other endpoints reported - BCF/BAF, LOEC/NOEC (specify, donot assess this item): 28-day NOEC (survival) ≥ 4190 mg/kg soil dw; 56-day NOEC (reproduction) = 128 mg/kg soil dw; 56-day LOEC (reproduction) = 235 mg/kg soil dw; BAFs ranging from 0.026 to 0.069.
* Was toxicity value below the chemical’s water solubility?n/a 
Other adverse effects (carcinogenicity, mutagenicity, etc. Donot assess this item) X
Score: major items – 4/4; overall score – 22/22 (100%)
EC reliability code: 1
Reliability category (high, satisfactory, low): high
Comments: Good control performance. Temperature 19.4–22.7°C. pH 5.50–6.67. Soil moisture 18.9–42.3%. Light intensity 573.4–595.5 lux. Should note, however, that preparation of test soils differed from that suggested by ASTM and bioaccumulation factors were reported based on concentration in tissue (ppm) relative to average 28-day concentration in soil.

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Appendix E: Upper-bounding Estimates of Daily Intake of HBCD by Canadians (µg/kg-bw per day by various age groups)

Route of Exposure0–6 months[1], [2], [3]0.5–4 years[4]5–11 years[5]12–19 years[6]20–59 years[7]60+ years[8]
Breast fedFormula fedNot formula fed
Ambient air[9]7.0 x 10-87.0 x 10-87.0 x 10-81.5 x 10-71.2 x 10-76.6 x 10-85.7 x 10-85.0 x 10-8
Indoor air[10]4.9 x 10-54.9 x 10-54.9 x 10-51.1 x10-48.2 x 10-54.7 x 10-54.0 x 10-53.5 x 10-5
Drinking water[11]nil2.9 x 10-51.1 x 10-51.2 x 10-59.6 x 10-65.5 x 10-65.7 x 10-66.0 x 10-6
Food[12]8.4 x 10-2nil2.6 x 10-23.3 x 10-22.4 x 10-21.4 x 10-21.2 x 10-27.9 x 10-3
Soil/ Dust[13]5.2 x 10-35.2 x 10-35.2 x 10-38.4 x 10-32.7 x 10-36.6 x 10-45.5 x 10-45.4 x 10-4
Total intake8.9 x 10-25.3 x 10-33.1 x 10-24.2 x 10-22.7 x 10-21.5 x 10-21.3 x 10-28.5 x 10-3
[1] Human milk: Based on 28 µg HBCD/kg lipid × 3% lipid human milk fat content as measured in the study, 750 g milk consumed per day and a body weight of 7.5 kg.
[2] Assumed to weigh 7.5 kg, to breathe 2.1 m3 of air per day, to drink 0.8 L of water per day (formula fed) or 0.3 L/day (not formula fed) and to ingest 30 mg of soil per day (Health Canada 1998).
[3] For exclusively formula-fed infants, intake from water is synonymous with intake from food. The concentration of HBCD in water of 270 pg/L used to reconstitute formula was based on unpublished data. No data were identified on levels of HBCD in formula in Canada or elsewhere. Approximately 50% of not formula-fed infants are introduced to solid foods by 4 months of age and 90% by 6 months of age (NHW 1990 in Health Canada 1998.
[4] Assumed to weigh 15.5 kg, to breathe 9.3 m3 of air per day, to drink 0.7 L of water per day and to ingest 100 mg of soil per day (Health Canada 1998).
[5] Assumed to weigh 31.0 kg, to breathe 14.5 m3 of air per day, to drink 1.1 L of water per day and to ingest 65 mg of soil per day (Health Canada 1998).
[6] Assumed to weigh 59.4 kg, to breathe 15.8 m3 of air per day, to drink 1.2 L of water per day and to ingest 30 mg of soil per day (Health Canada 1998).
[7] Assumed to weigh 70.9 kg, to breathe 16.2 m3 of air per day, to drink 1.5 L of water per day and to ingest 30 mg of soil per day (Health Canada 1998).
[8] Assumed to weigh 72.0 kg, to breathe 14.3 m3 of air per day, to drink 1.6 L of water per day and to ingest 30 mg of soil per day (Health Canada 1998).
[9] 2 pg or 2 x 10-6µg/m3 from the Canadian Arctic was selected (Xiao et al. 2010). All identified data for concentrations in ambient air presented in Table A-7 were considered, and this one was the maximum Canadian value. Canadians are assumed to spend three hours outdoors each day (Health Canada 1998).
[10] The median indoor air concentration of 180 pg/m3 or 0.00018 µg /m3from the United Kingdom was used as surrogate indoor air data for Canadians, n = 33 (Abdallah et al. 2008a). No levels of HBCD in Canadian indoor air were identified. Canadians are assumed to spend 21 hours indoors each day (Health Canada 1998).
[11] No levels of HBCD in Canadian drinking water were identified. For this reason, unpublished data on HBCD in lakes of the United Kingdom have been used as a surrogate 270 pg/L or 2.7 x 10-4 µg/L. All identified data for concentrations in water were considered.
[12] Estimates of intake from food are based upon concentrations in foods indentified in a market basket survey of U.S. food commodities. Concentrations of HBCD in food commodities, those representative of North America were obtained from a U.S. food market basket survey (Schecter et al.2009). In part I of this larger market basket study, total HBCD in composite samples of n=31 food types and n=310 samples were measured. Limits of detection values were used for non-detects. Inputs were as follows: 0.86 µg/kg ww in meat; 0.261 µg/kg ww in dairy; 0.01 µg/kg ww in eggs; 0.810 µg/kg ww in fat; 0.180 µg/kg ww in cereal; 0.022 µg/kg ww in fruit; and 0.018 µg/kg ww in vegetables. For fish, a value of 4.6 µg/kg (ΣHBCD; α-HBCD = 3.8 µg/kg, γ-HBCD = 0.8 µg/kg, β-HBCD = 0.03 µg/kg; approx. 35 ng/g lipid) from Lake Ontario lake trout was used as an estimate of HBCD in Canadian fish species (Tomy et al. 2004a). This is considered to be a reasonable high-end estimate of HBCD levels in northern and southern Canadian fish species.
[13] Highest Canadian dust level in Canadian homes reported by Abdallah et al. 2008b (1300 µg/kg dw) was selected. In North America and Europe, there is a large variation in HBCD levels in dust.

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Appendix F: Estimates of Oral Exposure to HBCD for Infants 6–24 Months from Mouthing Flame-retarded Cushion or Upholstered Furniture

Consumer product scenarioAlgorithm and AssumptionsEstimated exposure

Oral

mouthing of HBCD flame­retarded cushion or upholstered furniture

Based on alorgithm from

Environ International Corporation, 2003

 

Dose rate = [WS × Vs × FR × AF0 × EFmouth × 1] / bw

Where:

WS = Water solubility of α-HBCD is 48.8 µg/L
Vs = Salivary flow rate in a child’s mouth is 0.00022 L/min, from Watanabe et al. (1990) as cited in Environ (2003a, 2003b)
FR = Fractional rate of extraction by saliva is 0.05, default value
AF0 = Absorption factor by the oral route is 1, default value
EFmouth = Exposure frequency mouthing, 23 min/d based on: Juberg et al. (2001) 22 min/day for children 0–18 months who mouthed objects (n = 46); Smith and Norris (2003) 24 min/day for children 6–9 months (n = 15); and 23 min/day for children 15–18 months (n = 14) who mouth other objects, as reported in the EPA Child-Specific Exposure Factors Handbook (US EPA 2008)
BW = Body weight, assumed to be 10 kg for an infant 6–24 months when mouthing behaviour is most prevalent

1.2 × 10-3µg/kg-bw per day

Oral exposure of children to HBCD from sucking a fabric

Based on algorithm from

U.S. National Research Council, 2000

 

D = Sa × Af × µa × fcc / Wc

Where:

D = The dose rate of chemical (mass per unit body weight per unit time)
Sa = Mass per unit surface area, application rate to the fabric or back-coating. 2 mg/cm2 for HBCD as utilized in the EU HBCD risk assessment.
Af = The area of fabric sucked on each occasion, 50 cm2. Default selected by U.S. NRC subcommittee for U.S. NRC HBCD assessment (US NRC 2000).
µa = The fractional rate (per unit time) of FR extraction by saliva under the given conditions. Chemical­specific, 0.025/d, used by U.S. NRC in HBCD assessment. Based on extraction data for HBCD in polyester fiber in McIntyre et al. (1995) as cited in US NRC 2000.
fcc = The fraction (dimensionless) of the time a child sucks FR-treated fabric, 23 min/d based on: Juberg et al. (2001) 22 min/day for children 0–18 months who mouthed objects (n = 46); Smith and Norris (2003) 24 min/day for children 6–9 months (n = 15); and 23 min/day for children 15–18 months (n = 14) who mouth other objects as reported in the EPA Child-Specific Exposure Factors Handbook (2008)
Wc = Body weight, assumed to be 10 kg for an infant 6–24 months when mouthing behaviour is most prevalent

4.0 µg/kg-bw/day
Note: The EU mouthing textile exposure scenario assumed daily mouthing of 50 cm2 fabric back-coated with HBCD (2 mg/cm2), 0.9% saliva extraction rate during 30 minutes, 100% absorption, one mouthing every three days; 10 kg 1­year­old infant. The resulting exposure estimate was 30 µg/kg-bw per day when both sides of textile were available for mouthing. If the back side is not available, exposure was 3 µg/kg-bw per day. Calculated margins of safety for these exposure estimates ranged from 330–7600.

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Appendix G: PBT Model Inputs Summary Table

Model Input ParametersPhys-Chem/FateFatePBT ProfilingEcotoxicity

EPISuite

(all models, including: AOPWIN, KOCWIN, BCFBAF, BIOWIN and ECOSAR)

STP (1)

ASTreat (2)

SimpleTreat (3)

(required inputs are different depending on model)

EQC (required inputs are different if Type I vs. Type II chemical)TaPL3 (required inputs are different if Type I vs. Type II chemical)OECD POPs Tool

Arnot-

Gobas BCFBAF

Model

Gobas Wolf BMF Model

Canadian-POPs

(including: Catabol, BCF Mitigating Factors Model, OASIS Toxicity Model)

Artificial Intelligence

Expert System (AIES)/

TOPKAT/

ASTER)

SMILES CodeBrC(C(Br)
CCC(Br)C
(Br)CCC(Br)
C(Br)C1)C1
      BrC(C(Br)
CCC(Br)C
(Br)CCC(Br)
C(Br)C1)C1
x
Molecular weight (g/mol) x (1, 2, 3)641.7 (I,II)x (I,II)x    
Melting point (ºC)  x (I)x (I)     
Boiling point (ºC)         
Data temperature (ºC)  25 (I,II)x (I,II)     
Density (kg/m3) x (2)       
Vapour pressure (Pa)6.27 × 10-5 Pa[5]x (1, 3)x (I)x (I)     
Henry’s Law constant (Pa·m3/mol) x (3)       

Log Kaw

(air-water partition coefficient; dimensionless)

 x (2)2.63E-09 (II)x (II)x    

Log Kow

(octanol-water partition coefficient; dimensionless)

 x (1)x (I)x (I)x

7.74,

5.625 (γ-HBCD)

x  

Kow

(octanol-water partition coefficient; dimensionless)

 x (2, 3)       

Log Koc

(organic carbon-water partition coefficient – L/kg)

         
Water solubility (mg/L)

0.00345 mg/L[5]

(γ-HBCD)

x (1, 3)x (I)x     

Log Koa

(octanol-air partition coefficient; dimensionless)

      x  
Soil-water partition coefficient (L/kg)[1]  2502 (II)x (II)     
Sediment-water partition coefficient (L/kg)[1]  5004 (II)x (II)     
Suspended particles-water partition coefficient (L/kg)[1] x (2)25 020 (II)x (II)     
Fish-water partition coefficient (L/kg)[2]  8974 (II)x (II)     
Aerosol-water partition coefficient; dimensionless[3]  100 (II)x (II)     
Vegetation-water partition coefficient; dimensionless[1]   x (II)     
Enthalpy (Kow)   -20(3)     
Enthalpy (Kaw)   55(3)     
Half-life in air (days)  2.13 (I,II)x (I,II)x    
Half-life in water (days)  60 (I,II)x (I,II)x    
Half-life in sediment (days)  240 (I,II)x (I,II)     
Half-life in soil (days)  60 (I,II)x (I,II)x    
Half-life in vegetation (days)[4]   x (I,II)     
Metabolic rate constant (1/days)     **  
Biodegradation rate constant (1/days) or (1/hr)–specify 

x

(3, 1/hr)

(2, 1/days)

       
Biodegradation half-life in primary clarifier (t1/2-p) (hr) x (1)       
Biodegradation half-life in aeration vessel (t1/2-s) (hr) x (1)       
Biodegradation half-life in settling tank (t1/2-s) (hr) x (1)       
[1] derived from logKoc
[2] derived from BCF data
[3] default value
[4] derived from half-life in water
[5] user-defined value used for determining Henry’s Law constant only

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