Appendices of the Screening Assessment

Aromatic Azo and Benzidine-based Substance Grouping
Certain Monoazo Pigments

Environment and Climate Change Canada
Health Canada
May 2016

Table of Contents

• Appendix A: Chemical Identity, Structures, Molecular Formulas and Molecular Weights of the 33 Monoazo Pigments, Organized by Subset
• Appendix B: Experimental Physical and Chemical Properties (at Room Temperature when Applicable) of Monoazo Pigments and their Analogues
• Appendix C: Experimental Data on Biodegradation of Monoazo Pigments and their Analogues
• Appendix D: Experimental Aquatic Toxicity Data for the 33 Monoazo Pigments and their Analogues
• Appendix E: Ecological Exposure Calculations for Monoazo Pigments
• Appendix F: Exposure Estimates from Use of Cosmetics and Personal Care Products
• Appendix G: Exposure Estimates from Use of Paint
• Appendix H: Oral Exposure Estimates to PR5 and PO5 from Incidental Ingestion of Paper (Toddlers)
• Appendix I: Exposure to of Pigment in Permanent Tattoo Ink (Adult) for PR4, PR112 and PY3
• Appendix J: Benchmark Dose Calculations for PR3, PO5, PR4 and PR53:1
• Back to the Screening Assessment

Appendix A: Chemical Identity, Structures, Molecular Formulas and Molecular Weights of the 33 Monoazo Pigments, Organized by Subset

Top of Page

Appendix B: Experimental Physical and Chemical Properties (at Room Temperature when Applicable) of Monoazo Pigments and their Analogues

Top of Page

Appendix C: Experimental Data on Biodegradation of Monoazo Pigments and their Analogues

Top of Page

Appendix D: Experimental Aquatic Toxicity Data for the 33 Monoazo Pigments and their Analogues

Top of Page

Appendix E: Ecological Exposure Calculations for Monoazo Pigments

A5.1 Aquatic Exposure Calculations for Pigment Manufacture

A large pigment manufacturing facility in Canada was selected for estimating the level of aquatic exposure to the Monoazo Pigments. The estimate was derived as follows.

The daily production of the Monoazo Pigments was an essential parameter for the aquatic exposure calculations, but was unknown. This parameter was estimated based on the reported total quantity of organic pigments manufactured in Canada, 3 000 000 kg/year (Linak et al. 2011), and the number of annual production days, 300 days/year, derived for the manufactured quantity of 3 000 000 kg/year according to the European Commission’s Technical Guidance Document on Risk Assessment (European Commission 2003):

Daily production of Monoazo Pigments
= Annual quantity of organic pigments manufactured / Annual production days
= 3 000 000 kg/year / 300 days/year
= 10 000 kg/day

Environment Canada conducted a number of site visits to pigment manufacturing facilities in 2010 (Environment Canada 2010) and learned that the pigment production equipment was cleaned with water on a regular basis. The wastewater generated was subsequently treated for solids removal by an on-site wastewater treatment system prior to discharge to the sewer system. Environment Canada also conducted various site visits to other types of facilities, such as latex paint formulation (Environment Canada 2013a), powder coatings manufacturing (Environment Canada 2013b), cosmetics manufacturing (Environment Canada and Health Canada 2010) and tanktruck cleaning facilities (Environment Canada 2009b). All these site visits, including those for pigment manufacture, showed that the products lost to wastewater from equipment cleaning varied in a wide range, but did not exceed 10% of the total production or the equipment holding volume. This 10% value was used as a conservative estimate for the emission factor to wastewater from the cleaning of the pigment production equipment.

Emission factor to wastewater from equipment cleaning = 10%

The daily release of the Monoazo Pigments to wastewater was then estimated by multiplying the daily production by the emission factor:

Daily release of Monoazo Pigments to wastewater
= Daily production of Monoazo Pigments × Emission factor to wastewater from equipment cleaning
= 10 000 kg/day × 10%
= 1000 kg/day

It was reported that on-site industrial primary wastewater treatment was capable of removing 90% of pigments with water solubility below 1 mg/L (OECD 2009, p. 58). Since all the Monoazo Pigments have water solubility well below 1 mg/L and the on-site wastewater treatment of the facility evaluated was expected to have at least primary or equivalent removal, according to the site visits to pigment manufacturing facilities (Environment Canada 2010), the removal of 90% was used for on-site wastewater treatment.

On-site wastewater treatment removal = 90%

The daily release of the Monoazo Pigments to the sewer system was then estimated:

Daily release of Monoazo Pigments to sewer system
= Daily release of Monoazo Pigments to wastewater × (1 − On-site wastewater treatment removal)
= 1000 kg/day × (1 − 0.9)
= 100 kg/day

The treated wastewater discharged from the facility was further treated by an off-site wastewater treatment system. This system had a flow rate of 334 900 000 L/day. The concentration of the Monoazo Pigments in the influent was estimated by dividing the daily release to the sewer system by the flow:

Concentration of Monoazo Pigments in influent
= Daily release of Monoazo Pigments to sewer system / Flow rate of off-site wastewater treatment system
= 100 kg/day / 334 900 000 L/day
= 298.6  × 10⁻⁹ kg/L
= 298.6 μg/L

The removal of Monoazo Pigments by the off-site wastewater treatment system was estimated by models. The system was a secondary type, and its removal was estimated by ASTreat (2006) to be in the range of 0.5–49.2%, based on the log K_owrange of −0.75 to 4.62 for the Monoazo Pigments. In this estimate, the Monoazo Pigments were considered to be non-volatile substances and were assumed not to biodegrade, due to a lack of biodegradation data. The removal estimated was therefore a result of sludge sorption only. The lower-end value was used in order to derive a conservative aquatic PEC.

Off-site wastewater treatment removal = 0.5%

The concentration of the Monoazo Pigments in the effluent was then calculated:

Concentration of Monoazo Pigments in effluent
= Concentration of Monoazo Pigments in influent × (1 − Off-site wastewater treatment removal)
= 298.6 μg/L × (1 − 0.005)
= 297 μg/L

The receiving water for the off-site wastewater treatment system was a large lake, and the dilution factor at the discharge point was assumed to be 10-fold. Thus, the concentration of the Monoazo Pigments in receiving water near the discharge point, or the aquatic PEC, was estimated:

Aquatic PEC
= Concentration of Monoazo Pigments in effluent / Receiving water dilution factor

= 297 μg/L / 10
= 29.7 μg/L

This aquatic PEC for pigment manufacture is presented in Table 14.

A5.2 Aquatic Exposure Calculations for Paint and Coating Formulation

Seventy-five paint and coating formulation facilities were identified as industrial users of the Monoazo Pigments from CEPA 1999 section 71 surveys (Canada 2006, 2007, 2008, 2011), and eight of them were determined to be the largest users. On average, these eight facilities used 5000–10 000 kg/year per pigment for one or more Monoazo Pigments. The eight facilities were therefore selected to determine the level of aquatic exposure for the paint/coating formulation sector. In comparison, the other facilities used quantities below 5000 kg/year per pigment on average. Less than five of these other facilities were initially identified among the largest users based on the above-mentioned CEPA 1999 section 71 surveys, but each of these facilities was found to use less than 5000 kg/year for all Monoazo Pigments combined through follow-up questions (2013 emails from facilities to Environment Canada; unreferenced).

Pigments can be released to the aquatic environment through wastewater treatment when the formulation equipment is cleaned with water. The cleaning is expected for water-based paints and coatings. The exposure calculations presented below were therefore based on data relating to water-based paints and coatings.

The size of a paint/coating production batch was found to range from 1000 to 19 000 kg, according to an analysis of industry data (Environment Canada 2012). Since the amount released from equipment cleaning is proportional to the batch size, the largest batch size (19 000 kg) was used in order to derive a conservative PEC.

Maximum batch size = 19 000 kg

The amount of residue lost to equipment cleaning was also obtained from an analysis of industry data. This amount, commonly expressed as a percentage of a batch size and referred to as an emission factor to wastewater, was 0.3% (Environment Canada 2012) and was used for the paint/coating formulation scenario.

Emission factor to wastewater = 0.3%

The content of pigments in water-based paints and coatings ranged from 15% to 45%, according to a number of site visits to paint/coating formulation facilities (Crechem Technologies 2003), and 2–30% from a more recent site visit (Environment Canada 2013c). The highest content (45%) was selected as the worst-case scenario.

Content of pigments in paints/coatings = 45%

An analysis of industry data showed that the cleaning of coating formulation equipment was completed within 1 day (Environment Canada 2012). The maximum amount of pigments released to on-site raw wastewater was then estimated:

Maximum daily amount released to on-site raw wastewater
= Maximum batch size × Maximum content of pigments in paint/coatings × Emission factor to wastewater
= 19 000 kg × 45% × 0.3% = 25.7 kg/day

Site visits to paint/coating formulation facilities indicated that on-site wastewater treatment for solids removal was common for large facilities (Crechem Technologies 2003). The site visits also indicated that the treated wastewater from the on-site treatment was treated further by off-site wastewater treatment before reaching the aquatic environment. Both on-site and off-site wastewater treatment were therefore assumed in the exposure calculations.

Pigments with water solubility under 1 mg/L are expected to be 90% removed via primary sludge (OECD 2009). Since all the Monoazo Pigments have water solubility well below 1 mg/L and on-site wastewater treatment systems are expected to have at least primary or equivalent removal, the removal efficiency can be expected to be 90% for on-site treatment.

On-site wastewater treatment removal = 90%

The maximum amount released to the sewer system after on-site wastewater treatment was then estimated:

Maximum amount released to sewer system
= Maximum daily amount released to on-site raw wastewater × (1 − On-site wastewater treatment removal)
= 25.7 kg/day × (1 − 0.9)
= 2.57 kg/day

The calculations below depend upon the location of each facility. For a facility at Site C-2, the wastewater flow rate of the off-site wastewater treatment system was 14 700 000 L/day. The concentration of pigments in the influent was then estimated:

Concentration of pigments in influent
= Maximum amount released to sewer system / Flow rate of off-site wastewater treatment system
= 2.57 kg/day / 14 700 000 L/day
= 1.75 × 10⁻⁷ kg/L = 175 μg/L

The removal efficiencies of the off-site wastewater treatment systems at the eight paint/coating formulation sites were estimated by models. The treatment systems used at these sites were all secondary, and their removal efficiencies were estimated by ASTreat (2006). The Monoazo Pigments were considered to be non-volatile and were assumed not to biodegrade through wastewater treatment, due to a lack of biodegradation data. The removal efficiencies estimated were therefore a result of sludge sorption only. These estimates were in the range of 0.5–49.2% for secondary systems, based on the log K_ow range of −0.75 to 4.62. The lower-end value was used in order to derive conservative aquatic PECs.

Off-site wastewater treatment removal = 0.5%

For Site C-2, the concentration of pigments in the effluent was estimated:

Concentration of pigments in effluent
= Concentration of pigments in influent × (1 − Off-site wastewater treatment removal)
= 175 μg/L × (1 − 0.005) = 174 μg/L

The aquatic PEC was estimated by dividing the effluent concentration by an appropriate dilution factor of the receiving water. Since the aquatic PEC is determined near the discharge point, the receiving water dilution factor selected should be applicable to this requirement. The full dilution potential of a river based on its 10^th percentile flow rate is considered appropriate if the dilution factor is between 1 and 10. Otherwise, a 10-fold dilution is assumed for both large rivers and still waters. The receiving water for the wastewater treatment system at Site C-2 is a river with a 10^th percentile flow rate of 98 120 000 L/day. Thus, the dilution factor was calculated as:

Receiving water dilution factor = 10^th percentile flow rate / Flow rate of off-site wastewater treatment system
= 98 120 000 L/day / 14 700 000 L/day
= 6.7

This dilution factor was used in the calculation for the aquatic PEC at Site C-2:

Aquatic PEC =
Concentration of pigments in effluent / Receiving water dilution factor
= 174 μg/L / 6.7 = 25.9 μg/L

The aquatic PEC results for the eight paint/coating formulation facilities are summarized in Table 14.

A5.3 Aquatic Exposure Calculations for Deinking Operations

Seventeen facilities were identified as performing recycled paper deinking operations from the Pulp and Paper Canada Directory (2013), the Lock-wood Post Directory (2011) and FisherSolve™ Platform (2013). Out of this total, 13 facilities were found to have sufficient information for aquatic exposure calculations. The 13 facilities were judged to be a good representation of the Canadian deinking sector.

The aquatic PEC was estimated for each of the 13 facilities. These facilities generated and treated their respective wastewater on site and subsequently discharged the treated wastewater directly to the receiving water. The aquatic PEC for each facility was estimated based on the quantity of the Monoazo Pigments entering the facility, the emission factor to wastewater, the wastewater volume, the removal efficiency of the on-site wastewater treatment and the dilution of the receiving water.

A detailed explanation of the aquatic PEC calculations for the Monoazo Pigments is provided below using Site D-1 as an example.

In Canada, the quantity of paper recycled was 4 170 000 tonnes, or 69% of the waste paper generated in 2010, according to the Pulp and Paper Products Council (2012 e-mail from Marketing Strategy and Sustainability Consulting, Kitchener, Ontario, to Ecological Assessment Division, Environment Canada; unreferenced). These figures translated into 6 043 000 tonnes of waste paper generated in 2010 in Canada:

Quantity of waste paper generated: = 4 170 000 tonnes / 69% = 6 043 000 tonnes/year

The average content of the Monoazo Pigments in printed paper was estimated by dividing the total quantity of the Monoazo Pigments used for printing by the quantity of waste paper generated. The total quantity of the Monoazo Pigments used for printing was in the range of 10 000–100 000 kg/year, as per CEPA 1999 section 71 surveys (Canada 2006, 2007, 2008, 2011). The higher-end value of this range was used to derive a conservative average content of Monoazo Pigments in waste paper:

Average content of pigments in paper: : (100 000 kg/year) / 6 043 000 tonnes/year = 0.0165 kg/tonne

This average content was used to estimate the amount of the pigments entering a given deinking facility based on its deinking capacity. For example, the deinking capacity of the facility at Site D-1 was 71 375 tonnes/year (FisherSolve™ Platform 2013). The annual input of the pigments into the facility was then estimated:

Annual input of pigments = 0.0165 kg/tonne × 71 375 tonnes/year = 1178 kg/year

The facility at Site D-1 operates 350 days/year on a continuous basis (FisherSolve™ Platform 2013). The daily input of the pigments into the facility at Site D-1 was estimated:

Daily input of pigments: (1178 kg/year) / 350 days/year = 3.37 kg/day

A literature search was conducted to find emission factors to wastewater from deinking operations. Few data were found. An industry association was then contacted, and it provided an estimate of 20% for the proportion of pigments entering wastewater from deinking (2013 telephone discussions between a pulp and paper expert from the industry association and Environment Canada; unreferenced). This estimate was used in further calculations.

Emission factor to wastewater = 20%

The daily quantity of the Monoazo Pigments emitted to raw wastewater from the facility at Site D-1 was estimated based on the 20% emission factor and the daily input of Monoazo Pigments into the facility:

Daily emission of pigments to raw wastewater = 3.37 kg/day × 20% = 0.67 kg/day

The concentration of Monoazo Pigments in raw wastewater was estimated by dividing the daily emission by the daily flow rate of the wastewater generated. For Site at D-1, the daily flow rate of the wastewater generated was 40 000 000 L/day (FisherSolve™ Platform 2013). The concentration of Monoazo Pigments in raw wastewater was then calculated:

Concentration of pigments in raw wastewater =  (0.67 kg/day × 10⁹ µg/kg) / 40 000 000 L/day = 16.8 μg/L

where 10⁹ μg/kg is a conversion factor.

Pigments with water solubility below 1 mg/L are expected to be 90% removed via primary sludge (OECD 2009). Since all the Monoazo Pigments have water solubility well below 1 mg/L and the wastewater generated from deinking facilities in Canada is subject to secondary treatment, the reduction in the concentration of the Monoazo Pigments would be at least 90% through wastewater treatment.

For the facility at Site D-1, the maximum concentration of the Monoazo Pigments in treated wastewater was estimated:

Maximum concentration of pigments in treated wastewater
= 16.8 μg/L × (1 − 0.9) = 1.7 μg/L

The receiving water for the facility at Site D-1 is a river with a 10^th percentile flow of 950 400 000 L/day. The full dilution capacity of the receiving water was estimated as the ratio of the 10^th percentile flow to the daily wastewater flow:

Receiving water full dilution capacity =(950 400 000 L/day) / 40 000 000 L/day = 24

In estimating the concentration of a chemical in receiving water, an appropriate dilution factor should be used to properly characterize the concentration near the discharge point. For the purpose of this risk assessment, 10-fold dilution was chosen to account for limited dilution near the discharge point when the full dilution capacity was over 10. For the facility at Site D-1, the concentration of the Monoazo Pigments in receiving water near the discharge point, or aquatic PEC, was therefore estimated:

Aquatic PEC = 1.7 µg/L / 10 = 0.17 μg/L

The aquatic PEC results for all the deinking sites are summarized in Table 14.

A5.4 Sediment Exposure Calculations

An equilibrium sediment–water partition approach described by the European Chemicals Agency (ECHA 2010) was used to estimate the concentration of the Monoazo Pigments in sediment. This approach assumes that the concentration in bottom sediment is in equilibrium with the concentration in the overlying water. At equilibrium, the PEC in bottom sediment can linearly correlate with the concentration in the aqueous phase of the overlying water as follows:

Sediment PEC = K_swC_w

where:

K _sw:

sediment–water partition coefficient (L/kg)

C _w:

chemical concentration in aqueous phase (mg/L)

The sediment–water partition coefficient (K_sw, L/kg) can be estimated from the organic carbon (OC) fraction of the sediment (F_oc, kg OC/kg), the sorptive capacity of the sediment’s OC (A_oc, L/kg OC) and the substance’s octanol–water partition coefficient (K_ow, unitless) (Gobas 2010):

K_sw = F_ocA_ocK_ow

The sediment PEC can then be calculated from the equation:

Sediment PEC = F_ocA_ocK_owC_w

The concentration in the aqueous phase (C_w, mg/L) can be estimated from the aquatic PEC (mg/L). There are three distinctive phases in the water column: aqueous phase, particulate suspended sediment and dissolved suspended sediment (Gobas 2007). Accordingly, the total concentration in the water column, or the aquatic PEC (mg/L), can be expressed as a sum of the concentrations in the aqueous phase (C_w, mg/L), particulate suspended sediment (C_ps, mg/L) and dissolved suspended sediment (C_ds, mg/L):

Aquatic PEC = C_w + C_ps + C_ds

When the OC phase in particulate or dissolved suspended sediment is the phase of sorption for a substance, the above equation can be converted to an expression for estimating the ratio of the aquatic PEC (mg/L) to the concentration in the aqueous phase (C_w, mg/L) (Gobas 2007):

Aquatic PEC/C_w = 1 + (X_psF_pocA_poc + X_dsF_docA_doc)K_ow

where:

A _poc:

sorptive capacity of particulate OC relative to octanol (L/kg OC)

A _doc:

sorptive capacity of dissolved OC relative to octanol (L/kg OC)

F _poc:

OC fraction of particulate suspended sediment (kg OC/kg)

F _doc:

OC fraction of dissolved suspended sediment (kg OC/kg)

K _ow:

octanol–water partition coefficient (unitless)

X _ps:

content of particulate suspended sediment in water column (kg/L)

X _ds:

content of dissolved suspended sediment in water column (kg/L)

In Canada, the middle level for the content of particulate suspended sediment in the water column (X_ps) was 47 mg/L (Environment Canada 2013d). This value was used in the derivation of the sediment PECs at the sites evaluated.
 
X_ps = 47 mg/L = 4.7 × 10⁻⁵ kg/L

According to Gobas (2010), the OC fraction of particulate suspended sediment varied from 0.1 to 0.2 kg OC/kg sediment. The lower end of this range was used in order to derive conservative sediment PECs.

F_poc = 0.1 kg OC/kg

Karickhoff (1981) proposed a value of 0.41 L/kg OC for the sorptive capacity of sediment’s OC based on a set of 17 sediment and soil samples and various hydrophobic non-polar organic compounds. This value was used for the sorptive capacity of particulate OC, Apoc.

A_poc = 0.41 L/kg OC

In Canada, the dissolved OC content in the water column averaged 2.7 mg OC/L (Environment Canada 2013d). This value was used in the derivation of the sediment PECs at the sites evaluated. Note that this OC content equals the product of the content of dissolved suspended sediment (X_ds, mg/L) and its OC fraction (F_doc, kg OC/kg):

X_dsF_doc = 2.7 mg OC/L = 2.7 × 10⁻⁶ kg OC/L

Gobas (2007) provided an estimate of 0.08 L/kg OC for the sorptive capacity of dissolved OC, A_doc. This estimate was used.

A_doc = 0.08 L/kg OC

The octanol–water partition coefficient (K_ow) exhibits a significant influence on the sediment PEC. According to the following two equations, described previously:

Sediment PEC = F_ocA_ocK_owC_w

Aquatic PEC/C_w = 1 + (X_psF_pocA_poc + X_dsF_docA_doc)K_ow

the dependence of the sediment PEC on K_ow is given as:

Sediment PEC = Aquatic PEC × F_ocA_oc/(1/K_ow + X_psF_pocA_poc + X_dsF_docA_doc)

This dependence reveals that the sediment PEC approaches zero for water-soluble substances with a low K_ow and approaches a maximum constant concentration for highly hydrophobic substances with a high K_ow. In other words, the sediment PEC increases with K_ow. The log K_ow values for the Monoazo Pigments were in the range of −0.75 to 4.62. The higher-end value of this range was used to derive conservative sediment PECs.

log K_ow = 4.62, or K_ow = 41 687

The ratio of the aquatic PEC to the concentration in the aqueous phase (C_w) was calculated:

Aquatic PEC/C_w = 1 + (X_psF_pocA_poc + X_dsF_docA_doc)K_ow
= 1 + (4.7 × 10⁻⁵ kg/L × 0.1 kg OC/kg × 0.41 L/kg OC + 2.7 × 10⁻⁶ kg OC/L × 0.08 L/kg OC) × 41 687
= 1 + 2.14 × 10⁻⁶ × 41 687
= 1 + 0.089 = 1.089

As an example, the aquatic PEC at Site C-2 for the formulation of paints and coatings was estimated as 25.9 µg/L. The concentration in the aqueous phase (C_w) at this site was then calculated from the ratio of the aquatic PEC to C_w:

C_w = Aquatic PEC/1.089 = 25.9 µg/L/1.089 = 23.8 µg/L

Gobas (2010) suggested a default value of 0.01–0.03 OC/kg for the OC fraction of bottom sediment in rivers. The higher end of this range was selected as a standard for the sediment PECs derived.

F_oc = 0.03 kg OC/kg

As for particulate suspended sediment, the sorptive capacity of bottom sediment’s OC was taken as 0.41 L/kg OC, based on the work from Karickhoff (1981).

A_oc = 0.41 L/kg OC

The sediment PEC at Site C-2 was then estimated from the above values:

Sediment PEC = F_ocA_ocK_owC_w
= 0.03 kg OC/kg × 0.41 L/kgOC × 41 687 × 23.8 µg/L
= 512.8 L/kg × 23.8 µg/L
= 12 205 µg/kg
= 12.2 mg/kg

The sediment PECs for all the sites were estimated according to the above method and are summarized in Table 14.

A5.5 Soil Exposure Calculations

The deinking sector was selected to derive a conservative estimate of the concentration of Monoazo Pigments in soil. Among the major release sectors (pigment manufacture, paint/coating formulation and deinking) considered for exposure calculations, the deinking sector represents the highest release to sludge. When this sludge is converted to biosolids and subsequently applied to land, the entire quantity of the Monoazo Pigments removed from deinking can end up in soil, while the other two sectors release only a small percentage to soil through biosolids generated from off-site wastewater treatment systems. The deinking sector was therefore expected to result in the highest concentrations of Monoazo Pigments in soil.

The concentration of Monoazo Pigments in soil was estimated under a conservative scenario. In this scenario, it was assumed that the pigment-containing biosolids generated from the deinking sector were applied onto agricultural land at an average rate of 28 wet tonnes/ha, as reported in Quebec (Hébert and Chaker 2011), over a substantial number of years (10 years). It was also assumed that the pigments were accumulated in soil and did not incur any degradation, volatilization, soil runoff or leaching losses. Detailed calculations are presented below.

The total annual quantity of the Monoazo Pigments used for printing was in the range of 10 000–100 000 kg/year, as per CEPA 1999 section 71 surveys (Canada 2006, 2007, 2008, 2011). The higher-end value of this range was used to derive a conservative soil exposure estimate.

Total annual quantity of Monoazo Pigments = 100 000 kg/year

According to the Pulp and Paper Products Council (2012 e-mail from Marketing Strategy and Sustainability Consulting, Kitchener, Ontario, to Ecological Assessment Division, Environment Canada; unreferenced), in Canada, the paper recycling rate in 2010 was 69%. Based on this rate, the quantity of the Monoazo Pigments in recycled paper was estimated:

Quantity of pigments in recycled paper = 100 000 kg/year × 69% = 69 000 kg/year

As a conservative estimate, it was assumed that the entire quantity of the Monoazo Pigments in recycled paper ended up in sludge from deinking mills.

Quantity of pigments in sludge = 69 000 kg/year

Newsprint mills with deinking operations reported an average sludge production rate of 835 oven-dry tonnes/day, according to a contract study commissioned by Environment Canada (2009a). This daily rate translates to an annual rate of 292 250 tonnes/year, assuming that newsprint mills operate 350 days/year.

Annual sludge production from deinking mills = 292 250 tonnes/year

The concentration of the Monoazo Pigments in the sludge from deinking mills was estimated by dividing the quantity of the pigments in the sludge by the sludge quantity:

Concentration of pigments in sludge =  (69 000 kg/year) / 292 250 tonnes/year = 0.236 kg/tonne = 236 mg/kg

The land application rate of pulp and paper mill sludge in Quebec was used. The average rate was reported to be 28 wet tonnes/ha (Hébert and Chaker 2011). Assuming an average of 40% solids (Environment Canada 2009a), this translates to an average land application rate of approximately 11 dry tonnes/ha. Since 1 ha = 10 000 m², the annual land application rate would be:

Annual land application rate = 11 tonnes/ha per year = 1.1 kg/m² per year

The European Chemicals Agency (ECHA 2010) suggested using 10 consecutive years as a length of accumulation in evaluating soil concentrations resulting from biosolids application. The quantity of the Monoazo Pigments received per square metre of the amended soil during this 10-year period would be:

Quantity of pigments per square metre of soil
= Annual land application rate × 10 years × Concentration of pigments in sludge
= 1.1 kg/m² per year × 10 years × 236 mg/kg
= 2596 mg/m²

The European Chemicals Agency (ECHA 2010) also suggested using 20 cm (i.e., 0.2 m) as the ploughing depth in determining a mixing layer. Using a dry-soil density of 1200 kg/m³ (Williams 1999), the mass of the top 20-cm soil layer per square metre was estimated:

Mass of ploughing layer per square metre = 1200 kg/m³ × 1 m² × 0.2 m = 240 kg/m²

The soil PEC was determined by dividing the quantity of the pigments upon 10-year land application by the mass of ploughing layer soil per square metre:

Soil PEC = (2596 mg/m²) / 240 kg/m² = 10.8 mg/kg

Top of Page

Appendix F: Exposure Estimates from Use of Cosmetics

Top of Page

Appendix G: Exposure Estimates from Use of Monoazo Pigments in Paint Products

Top of Page

Appendix H: Estimate of Short-Term Exposure to Monoazo Pigment in Permanent Tattoo Ink (Adult)

Exposure factors were derived based on a study that examined the loss of a monoazo tattoo pigment from mouse skin in vivodue to biological dissemination and photochemical decomposition (Engel et al. 2009). While this study was specifically on Pigment Red 22 (PR22), a generic approach is taken as a conservative approach to estimate exposure to any azo pigment in tattoo ink. In Engel et al. (2009), 19 hairless female SKH-1 mice, divided into four groups, were tattooed on their dorsa with PR22. Exposure to normal ambient light for 32 days after 10 days of recovery following the initial injection (total of 42 days) resulted in a 32% reduction of PR22 in skin. The loss percentage was considered predominantly attributable to biological dissemination of the tattoo pigment into the lymphatic system. A separate group of mice exposed to simulated solar radiation instead of normal ambient light resulted in a 60% reduction in the initial skin pigment concentration. The fraction of photodecomposed Pigment Red 22 that resulted in the formation of aromatic amines is unknown for simulated solar radiation. Therefore, this exposure scenario focuses on systemic exposures of the intact pigment only.

Exposure scenario (Danish EPA 2012 unless specified otherwise)

Route of exposure: Injection into the dermis
Average skin concentration: 2.53 mg pigment/cm² ex vivo human or pig skin (Engel et al. 2008)
Realistic worst-case skin concentration: 9.42 mg pigment/cm²
Skin area covered (average): 430 cm²
Skin area covered (whole back): 1090 cm²
Amount of azo pigment in tattoo potentially available for absorption:
AV (average): 1.09 g
AW (whole back): 10.3 g
BW (adult body weight): 70.9 kg-bw (Health Canada 1998)
FP: Fraction of intact pigment in dermis that is mobilized into the lymphatic system:32% over 42 days (Engel et al. 2009)

Exposure to pigment = [(AV – AW) × FP] ÷ (BW × Length of study)

= [(1.09 – 10.3 g) × 0.32] ÷ [70.9 kg-bw × 42 days]
= 0.12–1.1 mg/kg-bw per day

Therefore, the short-term systemic daily exposure to monoazo pigments in tattooed individuals is assumed to be 0.12 mg/kg-bw per day on average and 1.1 mg/kg-bw per day as a conservative estimate.

Top of Page

Appendix I: Benchmark Dose Calculations for PR3, PR4 and PR53:1

Top of Page

Appendix J. Monoazo Pigments With Effects of Concern

Some of the Monoazo Pigments in this assessment have effects of concern based on potential carcinogenicity. The details for supporting the potential carcinogenicity for these substances are outlined in section 7.2 Health Effects Assessment (see specific sub-sections), and generally based on one or more of the following lines of evidence:

• Classifications by national or international agencies for carcinogenicity (may be a group classification).
• Evidence of carcinogenicity in animal studies and/or human epidemiology based on the specific substance.
• Potential to release one or more of the EU22 aromatic amines by azo bond cleavage.
• Read-across to related substances for which one or more of the above lines of evidence apply.