Appendices of the Screening Assessment

Aromatic Azo and Benzidine-based Substance Grouping
Certain Azo Acid Dyes

Environment and Climate Change Canada
Health Canada
June 2016

Table of Contents

• Appendix A: Supplementary Data Tables for Identities of Substances
• Appendix B: Ecological Aquatic Exposure Calculations for Azo Acid Dyes
• Appendix C: Summary of Dietary Exposure Estimates
• Appendix D: Estimated Exposures from Use of Products
• Appendix E: Azo Acid Dyes with Effects of Concern
• Back to the Screening Assessment

Appendix A: Supplementary Data Tables for Identities of Substances

Abbreviations:Abbreviations: CAS RN: Chemical Abstracts Service Registry Number; C.I.: Colour Index; NA: not available

Abbreviations: CAS RN: Chemical Abstracts Service Registry Number; C.I.: Colour Index; NA: not available; UVCB: unknown or variable composition, complex reaction products, or biological materials ; A: aromatic ring

Table A-4 Note

Abbreviations: K_ow: octanol-water partition coefficient; pKa: acid dissociation constant

[a]

Solubility and octanol-water partition coefficient expressed at standard temperatures (~25°C) except where indicated otherwise.

Table A-5 Note

[a]

Solubility expressed at standard temperatures (~25°C) except where indicated otherwise.

Table A-6 Note

[a]

Solubility and octanol-water partition coefficient expressed at standard temperatures (~25°C) except where indicated otherwise.

Table A-7 Note

[a]

Solubility, octanol-water partition coefficient and vapour pressure expressed at standard temperatures (~25°C) except where indicated otherwise.

Table A-8 Note

[a]

Solubility, octanol-water partition coefficient and vapour pressure expressed at standard temperatures (~25°C) except where indicated otherwise.

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Appendix B: Ecological Aquatic Exposure Calculations for Azo Acid Dyes

The aquatic predicted environmental concentrations (PECs) of the Azo Acid Dyes at each site were estimated by following their flow path from a release point at a facility to a point of entry to the aquatic compartment. The first step in the calculations was to estimate the daily use quantity of the Azo Acid Dyes at a facility. This estimate was derived from an annual use quantity reported in the CEPA section 71 survey (Canada 2011). For each of the 72 facilities identified as the industrial users of theAzo Acid Dyes, the annual use quantity ranged from 100 to 50 000 kg/year:

Annual use quantity of Azo Acid Dyes at a facility = 100-50 000 kg/year

To estimate a daily use quantity from an annual use quantity, a method provided in the EC (2003b) Technical Guidance Document on Risk Assessment (Part II) was used. This method was applicable to the chemical industry and was judged to cover the formulation and industrial uses of the Azo Acid Dyes, except for textile dyeing. By this method, the number of annual operation days is given by the following equation (EC, 2003b):

Number of annual operation days
= 2Q for annual use quantity of 10 000 kg/year or less
= Q for annual use quantity over 10 000 kg/year but under 50 000 kg/year

where Q is annual use quantity expressed in tonne/year.

If q is used to represent the annual use quantity in kg/year (note that q = 1000Q), the daily use quantity of the Azo Acid Dyes at a facility is determined by dividing the annual use quantity at a facility by the number of operation days:

Daily use quantity of Azo Acid Dyes
= Annual use quantity of acid dyes at a facility / Number of annual operation days
= q / Number of annual operation days
= 1000Q (kg) / Number of annual operation days
= 1000Q (kg) / 2Q (days) = 500 kg/day for annual use quantity of 10 000 kg/year or less
= 1000Q (kg) / Q (days) = 1000 kg/day for annual use quantity over 10 000 kg/year but under 50 000 kg/year

In cases where an annual use quantity is less than 500 kg/year, an estimated daily use quantity of 500 kg/day is an obvious overestimate. To correct this overestimate, the daily use quantity was conservatively assumed to equal the reported annual use quantity when the latter was under 500 kg/year.

For textile dyeing, the daily use quantity of the Azo Acid Dyes at a mill was unknown and was therefore estimated from literature data. According to US EPA (1994), a typical dyelot consisted of 454 kg of textile and was completed within 6 hours from batch dyeing or 8 hours from continuous dyeing. When a mill operated three shifts or 24 hours/day, the maximum number of dyelots completed per day would be four dyelots, and the quantity of textile dyed per day would be 1816 kg/day (454 kg/dyelot × 4 dyelots/day), as determined for batch dyeing. A typical dye use rate of 0.02 kg of dyes per kilogram of textile (Cai et al. 1999) was employed to estimate the daily use quantity of the Azo Acid Dyes at one mill:

Daily use quantity of Azo Acid Dyes used at one mill
= Daily quantity of textile dyed × Dye use rate
= 1816 kg/day × 0.02 kg/kg = 36 kg/day

The results for the daily use quantity of the Azo Acid Dyes were then summarized:

Daily use quantity of Azo Acid dyes at a facility
= Annual use quantity for facilities each using less than 500 kg/year, excluding textile dyeing
= 500 kg/day for facilities each using 500-10 000 kg/year, excluding textile dyeing
= 1000 kg/day for facilities each using 10 000-50 000 kg/year, excluding textile dyeing
= 36 kg/day for textile dyeing facilities

The number of annual operation days involved with the Azo Acid Dyes was then estimated by dividing the annual use quantity at a facility by the daily use quantity:

Number of annual operation days involved with Azo Acid Dyes
= Annual use quantity of acid dyes at a facility / Daily use quantity of Azo Acid Dyes at a facility

As an example, the number of annual operation days involved with the Azo Acid Dyes was estimated as follows for a hypothetical annual use quantity of 1000 kg/year at a food production facility:

Number of annual operation days involved with Azo Acid Dyes
= Annual use quantity of Azo Acid Dyes at a facility / Daily use quantity of acid dyes at a facility
= 1000 kg/year / 500 kg/day
= 2 days/year

In the second step, the daily release quantity of the Azo Acid Dyes from a facility was estimated based on emission factors to raw industrial wastewater. These emission factors were obtained from several emission scenario documents from the Organisation for Economic Co-operation and Development (OECD). The default emission factor from process equipment cleaning was reported as 2% (OECD 2011). This value was judged not to be applicable to textile or leather dyeing facilities. The textile dyeing facilities had a higher emission factor for Azo Acid Dyes, in the range of 2-15%, due to unfixed dyestuffs from dyeing operations (OECD 2004a). The maximum 15% emission factor was selected for conservative exposure estimates. The leather dyeing facilities also had a higher emission factor for acid dyes, at 20%, for the same reason (OECD 2004c). This 20% was selected. The remaining facilities were not expected to incur losses similar to those from textile or leather dyeing, and the emission factor to raw industrial wastewater for these facilities was assumed to equal the 2% default loss from process equipment cleaning. Therefore:

Emission factor to wastewater
= 15% for textile dyeing facilities from unfixed dyes
= 20% for leather dyeing facilities from unfixed dyes
= 2% for all other facilities from equipment cleaning

The daily release quantity of the Azo Acid Dyes to wastewater from a facility was estimated by multiplying the facility's daily use quantity of the Azo Acid Dyes by the appropriate emission factor to raw industrial wastewater. For example, the daily release quantity of the Azo Acid Dyes to raw industrial wastewater from a food production facility with a daily use quantity of 500 kg/day was estimated as follows:

Daily release quantity of Azo Acid Dyes to raw industrial wastewater at a facility
= Daily use quantity of Azo Acid Dyes at a facility × Emission factor to wastewater
= 500 kg/day × 2%
= 10 kg/day for a food production facility with a daily use quantity of 500 kg/day

It was unknown whether or not on-site industrial wastewater treatment was used at each of the 72 facilities. In the absence of this information, it was conservatively assumed that there was no on-site wastewater treatment. Thus, the daily release quantity to raw industrial wastewater at a facility was equal to the release quantity to a publicly-owned wastewater treatment system.

The third step was to estimate the concentrations of the Azo Acid Dyes in influent and effluent of the publicly-owned wastewater treatment system. The concentration in influent depends upon the flow of a publicly-owned wastewater treatment system. As an example, for a  wastewater treatment system with a flow of 40 000 000 L/day, the concentration of the acid dyes in wastewater influent can be estimated as follows for the food production facility releasing 10 kg/day of the Azo Acid Dyes to sewer:

Concentration of Azo Acid Dyes in wastewater influent of publicly-owned wastewater treatment system
= Daily release quantity of Azo Acid Dyes to sewer / Flow of publicly-owned wastewater treatment system
= 10 kg/day / 40 000 000 L/day = 2.5 × 10^-7 kg/L = 250 µg/L

The removal of the Azo Acid Dyes through local wastewater treatment systems was expected to be limited. Since they were highly water soluble and unlikely to be volatile, their removal by sludge sorption and volatilization was expected to be low, although certain sludge sorption is possible due to the electrostatic bonding of the ionizable Azo Acid Dyes with solids. Available ready biodegradation tests showed that the acid dyes were either not biodegradable or biodegraded to a limited extent in aerobic conditions. Biodegradation is more likely under anaerobic conditions. This limited biodegradability would likely translate into some limited biodegradation removal under wastewater treatment conditions. However, as a conservative estimate, the removal of the Azo Acid Dyes by local wastewater treatment systems via sludge sorption, volatilization and biodegradation was assumed to be zero:

Removal of Azo Acid Dyes by local wastewater treatment = 0%

Many of the 72 facilities were located in municipalities served by lagoons. These lagoons contained large volumes of water and had long hydraulic retention times. The retention time of a lagoon was in weeks to months, according to field data collected through the Chemicals Management Plan's (CMP) Monitoring and Surveillance Program at Environment and Climate Change Canada (Smyth 2012). The implication of a long retention time was that the Azo Acid Dyes entering a lagoon within a relatively short duration were subject not only to removal, although it was assumed to be 0% in the case of the Azo Acid Dyes, but also to dilution. As a result, the concentration of the Azo Acid Dyes in the lagoon effluent was reduced by lagoon dilution.

No quantitative method was available to determine the degree of lagoon dilution. Nevertheless, the ratio of a lagoon's retention time to a substance's release duration could be considered as the maximum dilution, because the ratio was equivalent to the full dilution or the volume ratio of the entire lagoon water to the wastewater containing a specific substance. As an estimate, the lagoon retention time in weeks to months was interpreted as 42 days (6 weeks) to 84 days (12 weeks), with an average of 63 days. The full lagoon dilution was then determined by dividing this average by an appropriate release duration for a given facility.

For example, the wastewater treatment system for the food production facility was a lagoon. The release duration from the facility with a daily use quantity of 500 kg/day would be 2 days when the annual use quantity of the Azo Acid Dyes at the facility was 1000 kg/year. The dilution in the lagoon was then determined as

Lagoon dilution
= Average lagoon hydraulic retention time / Release duration
= 63 days / 2 days
= 31.5

Such dilution was, however, not expected in primary or secondary treatment systems, because their hydraulic retention times were short, typically in hours.

The concentration of the Azo Acid Dyes in wastewater effluent was determined to be equal to the concentration in wastewater influent for primary and secondary wastewater treatment because of zero removal. For lagoons, the concentration in wastewater effluent was estimated by dividing the concentration in the wastewater influent by the lagoon dilution. For example, the concentration of Azo Acid Dyes in the lagoon's effluent associated with the food production facility was estimated as:

Concentration of Azo Acid Dyes in a lagoon's effluent
= Concentration of Azo Acid Dyes in wastewater influent / Lagoon dilution
= 250 µg/L / 31.5
= 7.9 µg/L

It should be noted that the influent and effluent flows of a wastewater treatment system were assumed to be equal in all concentration calculations. For the sake of convenience, they were also referred to as the flow of a wastewater treatment system.

The fourth and last step was to estimate the aquatic PEC by applying the receiving water dilution to the effluent concentration. Since the aquatic PEC was assessed near the discharge point, the receiving water dilution selected should also be applicable to this condition. The full dilution potential of a river was considered appropriate if it was between 1 and 10, based on its 10^th  percentile flow. Otherwise, the dilution was kept at 10 for both large rivers and still waters.

For example, the lagoon in the municipality where the food production facility was located had a flow of 40 000 000 L/day. Its receiving water was a river with a 10^th percentile flow of 484 000 000 L/day. Thus, the dilution factor of the receiving water was calculated as 12.1 (484 000 000 L/day / 40 000 000 L/day). Since this dilution factor was over the maximum value of 10 for dilution at the discharge point, the latter was used to derive the aquatic PEC:

Aquatic PEC
= Concentration of Azo Acid Dyes in a lagoon's effluent / Receiving water dilution factor
= 7.9 µg/L / 10
= 0.79 µg/L

When more than one facility discharged to the same wastewater treatment system at a given site, the aquatic PECs for the site were calculated as a range. The lower end of this range corresponded to the lowest of the concentrations in the receiving water estimated individually from each single facility. The higher end was the sum of all these individual concentrations. The range represented various discharge possibilities, from no discharge overlaps to maximum discharge overlaps. For example, there were two facilities at Site 3. The concentrations of the Azo Acid Dyes in the receiving water were estimated as 0.8 µg/L and 5.1 µg/L. The aquatic PECs for this site were then estimated in the range of 0.8 to 5.1 µg/L.

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Appendix C: Summary of Dietary Exposure Estimates

Dietary exposure estimates for Amaranth and Tartrazine were generated using a tiered approach, beginning with the calculation of single-day intakes. Single-day intakes can overestimate long-term consumption, particularly at the higher percentiles of the distribution, as they do not take into account the frequencies of consumption of different foods. Single-day intakes that are well below the acceptable daily intake (ADI) are considered sufficient for characterizing risk. However, when single-day intakes are close to or exceed the ADI, long-term intakes should be calculated in order to improve confidence in the risk characterization. As long-run averages^{Footnote 7} of single-day intakes for the Canadian population were not available, “usual intakes”, which make adjustments for frequency of food consumption by using a second 24-hour recall event, can be calculated.  

The single-day estimates of exposure to Tartrazine were well below the ADI and so it was not considered necessary to calculate usual intakes for that compound; however, the single-day estimates of exposure to Amaranth at the 90th percentile were sufficiently close to the ADI for certain age groups to warrant the calculation of usual intakes in order to improve confidence in the risk characterization.

For both exposure assessments, the amount of food and beverages consumed by the Canadian population and the frequency of consumption were obtained from the Canadian Community Health Survey (CCHS), Cycle 2.2: Nutrition (Statistics Canada 2004). This 24-hour dietary recall survey was carried out in 2004-2005. Using a stratified multistage cluster design, it obtained a sample size of 35 107 respondents of all ages living in private occupied dwellings in all ten provinces. A second 24-hour recall was conducted on a subset of respondents from each age-sex group, comprising approximately 29% of respondents -- a proportion selected to provide enough data on within-person consumption variability while minimizing the costs associated with additional interviews. This additional day of exposure is designed to be used in the calculation of “usual intakes”.  Measured body weights were used in deriving dietary exposures where possible, and self-reported body weights were used otherwise. Individuals under the age of two years did not have either measured or reported body weights, so weights were taken from the US Department of Agriculture Continuing Survey of Food Intakes by Individuals Survey (1994-1996,1998) for ages 0 to 23 months.

Where possible, maximum use-levels were obtained using the highest value reported in the data made available from the food industry (2013-14, personal communications between industry associations and Health Canada's Food Directorate ; unreferenced) or from the Canadian Food Inspection Agency's (CFIA) Food Safety Action Plan targeted surveys on food colours (CFIA 2010, 2011). In the absence of such information, the maximum use-levels were based, where possible, on data submitted to Health Canada's Bureau of Chemical Safety in response to a call for data issued in July 1976 . Otherwise, the maximum permitted use levels of Amaranth and Tartrazine found in the List of Permitted Colouring Agentswere applied.

Two additional conservative  assumptions were made in generating the exposure estimates. First, for specific foods for which the levels of use currently employed by industry were not available, the highest level of Amaranth or Tartrazine used in that category of foods was applied across the entire category. Second, when a food that contained Amaranth or Tartrazine was identified, it was assumed that all individuals consuming that food select the Amaranth or Tartrazine-containing version.

Amaranth

A distribution of exposure estimates for Amaranth was generated based on those respondents in the CCHS who consumed foods likely to contain Amaranth on the first day of the 24-hour recall survey, and was adjusted to usual intakes using factors specific to each age-sex group; these adjustment factors take into account, and attempt to minimize, the within-person component of variability as calculated from those individuals who reported consuming foods likely to contain Amaranth on both days of the survey using an adaptation of the method described by the US National Research Council in 1986 and reported in Karpinski and Nargundkar (1992)^{Footnote 8}. Exposure estimates were adjusted for consumers only and then combined with those of non-consumers^{Footnote 9} to provide an all-persons sample of usual intakes from which the mean and 90^thpercentiles were calculated.

Tartrazine

A distribution of single-day exposure estimates for Tartrazine was generated based on those respondents in the CCHS who consumed foods likely to contain Tartrazine on the first day of the 24-hour recall survey. The single-day estimates are considered to be conservative, because they are likely to overestimate long-term exposure to Tartrazine, especially at the upper percentiles, and also due to the assumptions described above (2013 email from Food Directorate, Health Canada, to Existing Substances Risk Assessment Bureau, Health Canada; unreferenced).

Table C-1 summarizes the dietary exposure estimates by age group. Tables C-2 and C-3 outline the maximum identified use-levels of Amaranth and Tartrazine, respectively, for the different food commodities used in generating these exposure estimates, and also list an estimate of the associated percent contribution of each food to overall dietary exposure to each substance.

Tables C-1 Note

[a]

Statistics Canada requires estimates published from the CCHS data to meet two requirements: firstly, a sample size for any given estimate of 30 or more respondents, and secondly, a coefficient of variation greater than 33.3%. As a result of these requirements, estimates for infants (less than 0.5 years of age) were excluded from the tables for this section.

[b]

Usual intake of Amaranth was calculated using an adaptation of the method described by the US National Research Council in 1986 (US NRC 1986) and reported in Karpinski and Nargundkar (1992). Intakes were adjusted for consumers only and combined with the non-consumers to provide an all-persons sample of usual intakes to calculate the mean and 90th percentile of Amaranth intake. As the exposure estimates for Tartrazine and Amaranth involve different levels of refinement (single-day and usual intakes, respectively), they are not directly comparable.

Table C-2 Note

[a]

Categories represent a number of different individual foods. As the maximum levels of use are specific to subgroups within each category, there may be more than one maximum use level in each category presented here.  Not all foods within a food category were identified to contain Amaranth. Non-use of Amaranth is not reflected in this column.

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Appendix D: Estimated Exposures from Use of Products

Exposures from use of products were estimated for different age groups based on body weights from Health Canada's exposure factors for the general population of Canada (Health Canada 1998):

• Infant (0-6 months): 7.5 kg
• Toddler (0.5-4 years): 15.5 kg
• Child (5-11 years): 21.0 kg
• Teenager (12-19 years): 59.4 kg
• Adult (20-59 years): 70.9 kg
• Senior (60+ years): 72.0 kg

Estimated Oral Exposures to Amaranth, Orange II and Tartrazine from Use of Products

Estimated oral exposures from products are indicated below. Exposures were estimated for an adult unless specified otherwise. Concentrations are based on notifications submitted under the Cosmetic Regulations to Health Canada (2011 and 2013 emails from Consumer Product Safety Directorate, Health Canada to Existing Substances Risk Assessment Bureau, Health Canada; unreferenced) and from Health Canada databases (LNHPD 2015; NMID 2011). Exposures to droplets of spray products that would typically be cleared via the gastrointestinal tract are considered to be negligible relative to exposures listed in Table D-1.

Tables D-1 Note

Abbreviations: Abbreviation: N/A, not applicable.

[a]

For clarification, only Tartrazine (not Amaranth and Orange II) was identified as an ingredient in certain non-prescription drugs at the cosmetic-drug interface.

Estimated Dermal Exposures to Amaranth, New Coccine, Orange II and Tartrazine from Use of Products

Estimated dermal exposures from products are indicated in Tables D-2 to D-5. Exposures were estimated for an adult unless specified otherwise. Concentrations are based on notifications submitted under the Cosmetic Regulations of Health Canada (2011 and 2013 emails from the Consumer Product Safety Directorate, Health Canada to the Existing Substances Risk Assessment Bureau, Health Canada; unreferenced) and from Health Canada databases (LNHPD 2015; NMID 2011).

Abbreviations: Abbreviation: N/A, not applicable.

Abbreviations: Abbreviation: N/A, not applicable.

Abbreviations: Abbreviation: N/A, not applicable.

Abbreviations: Abbreviation: N/A, not applicable.

Oral Exposure Parameters for Cosmetics and Non-Prescription Drugs at the Cosmetic-Drug interface

All assumptions (Table D-6) were ConsExpo default assumptions (RIVM 2006a) unless otherwise noted. All product scenarios are for adults unless otherwise indicated.

Dermal Exposure Parameters for Cosmetics and Non-Prescription Drugs at the Cosmetic-Drug interface

All assumptions (Table D-7) were ConsExpo default assumptions (RIVM 2006a) unless otherwise noted. An overall retention factor of 1 was used unless otherwise stated. Exposures were estimated for an adult unless otherwise specified.

Dermal and Oral Exposure from Textile Products

Exposure factors and algorithms for estimating exposure from textile products

Oral and dermal exposure from textile products

Dermal exposure estimate = (SA × AW × SCF × C × M × F) / BW

Oral exposure estimate = (SA × AW × C × M × F) / BW

Dermal exposure was estimated assuming full (100%) body coverage from wearing clothing to account for exposures from multiple pieces of apparel that cover the entire surface area of the body. Oral exposure was estimated for an infant mouthing a textile object (e.g., blanket, textile toy) on a daily basis.

SA: Total surface area

For dermal exposure (Health Canada 1998) = 18 200 cm²(adult; personal apparel); = 3020 cm² (infant; baby sleeper)
For oral exposure = 20 cm² (Zeilmaker et al. 2000)

AW: Area weight of textile = 20 mg/cm² (US EPA 2012)

SCF: Skin contact factor = 1

C: Concentration = 0.01 (unitless) (BfR 2007)
Based on the default model developed by the "Textiles" Working Group established at the German Federal Institute for Risk Assessment (BfR 2007), assuming that a standard textile garment of 100 g/m2 is dyed with 1% active dye ingredient.

M: Migration fraction = 0.0005 (BfR 2007)
The migration of azo dyes from textiles varies considerably depending on the type of fibre, the type of dye used, the dye load, dyeing technology and colour intensity and after treatment. The exposure from textiles is partly dictated by the amount of dye that migrates from textile material onto human skin (ETAD 1983) or via mouthing. The "Textiles" Working Group (BfR 2007) uses a peak initial migration of 0.5% to estimate exposure to dyes from newly bought unwashed garments, and the chronic migration rate is assumed to be 1/10th of the value measured for the first migration to reflect exposure after initial washes. It is assumed that the sweat migration rate is similar to the salivary migration rate; this is consistent with observations of leaching behaviours of dyes from textiles reported by Zeilmaker et al. (1999). Accordingly, the fraction of dye that migrates from a textile material is assumed to be 0.0005 for both dermal and oral exposure.

F: Frequency = 1×/day

P: Probability that a given Azo Acid Dye is present in textile = 10%
In the RIVM risk assessment of azo dyes and aromatic amines from garments and footwear (Zeilmaker et al. 1999), the authors derived a chance of 8% for the appearance of carcinogenic azo dyes and aromatic amines in garments based on four European studies. Presumably, there would be a higher prevalence in the use of non-EU22 amines and their dyes, compared to EU22 amines and related dyes, since the former are not prohibited. None of the Azo Acid Dyes used to dye textiles in Canada (i.e., Acid Black 24, Acid Black 26, Acid Blue 113, Acid Orange 33, Acid Red 6, Acid Red 138, CAS RN 70210-05-8, CAS RN 70210-06-9, CAS RN 71873-51-3 and CAS RN 84962-50-5) derive from EU22 amines; the prevalence of these dye is not clear because there is relatively limited product testing and monitoring on non-EU22 amines and associated dyes. Based on data available (Danish EPA 1998; Kawakami 2012; Health Canada 2013), the prevalence of certain non-EU22 amines was found to range from 0% to 23.7% (aniline). Since several dyes can derive from a given aromatic amine, the prevalence of an associated dye would be lower. Given the conservatism used in other parameters in this exposure scenario (e.g. full body coverage), the probability that a given Azo Acid Dye is present in a textile is assumed to be 10% in this Screening Assessment based on professional judgement. This is considered reasonable since the chances of an individual’s outfit containing a given Azo Acid Dye every day are low.

Dermal Exposure Estimate from Leather Products

Exposure factors and algorithms for estimating exposure from leather productsDermal exposure from leather products

Dermal exposure from leather products

Exposure estimate = (SA × AW × SCF × C × M) / BW

Direct skin contact with articles of leather can result in dermal exposure to dyes used in leather dyeing. Of all the leather products considered, the potential drivers for exposure are presented below: furniture, apparel (e.g., jackets, trousers and gloves), footwear (e.g., shoes and boots) and toys, where it is assumed that direct contact with the infant's palms can occur when playing with the toy. As a conservative approach, exposure is assumed for all products. The exposure estimates presented below are considered upper-bounding based on conservative assumptions, as well as not taking into account a final application of a polyurethane sealant coating, which would further reduce the consumer's dermal exposure to the leather dye.

SA: Surface area of skin contact (Health Canada 1998; Therapeutic Guidelines 2008)

• Shoes: 1275 cm² (adult feet)
• Boots: 4185 cm² (adult legs and feet)
• Gloves: 455 cm² (adult hands)
• Jackets and coats: 8920 cm² (adult trunk and arms)
• Trousers: 5820 cm² (adult lower body)
• Furniture: 5005 cm² (adult back, buttocks and back of thighs)
• Toys: 92.5 cm² (infant palms)

AW: Area weight of leather = 0.15 g/cm² (Danish EPA 2012)

SCF: Skin contact factor

• Shoes: 1
• Boots: 0.1
• Gloves: 0.1
• Jackets and coats: 0.19
• Trousers: 0.19
• Furniture: 0.1
• Toys: 1

When the entire leather article is in direct contact with the skin, SCF is assumed to be 1. When the leather article is in indirect contact with the skin (e.g., shielding due to interior lining), SCF is assumed to be 0.1, which is a default value used to account for exposure due to diffusion of sweat-extracted dye from the leather material through the shielding fabric onto the skin (Zeilmaker et al. 1999). When a portion of the leather article is in direct contact and the remaining portion is in indirect contact, a weighted SCF is calculated: [(SAdirect × 1) + (SAindirect × 0.1)]/(SAtotal).

C: Concentration = 0.02 (unitless weight fraction) (Øllgaard et al. 1998)

M: Migration fraction = 0.1% (derived from 0.39 over 365 days)

The dermal exposure to dyes from leather is partly dictated by the amount of dye that migrates from leather material onto human skin. Zeilmaker et al. (1999) measured the experimental leaching of azo dyes from leather footwear material to be 15% and 39%. The leaching was determined by extracting from 1 g of unwashed material from the upper side of a newly bought leather shoe with 100 mL sweat stimulant (extraction conditions: 16 hours at 37°C while shaking). These extraction conditions are expected to overestimate the migration of dyes from sweat. In estimating exposure to dyes from leather articles, it is assumed that 39% represents the amount of the dye that can leach over a period of 1 year, which would be equivalent to 0.1% leaching in 1 day.

Exposure from Other Products

Tartrazine was identified as an ingredient in domestic and institutional cleaning products (NMID 2011). Exposure to Tartrazine was estimated with ConsExpo 4.1 (ConsExpo 2006) using default parameters in the sentinel product scenario of an all-purpose spray cleaner (RIVM 2006b). Estimated exposures shown below are considered to be negligible compared with exposures from foods, cosmetics and non-prescription drugs at the cosmetic-drug interface.

Concentration: 1% (Weerdesteijn et al. 1999)
Inhalation rate: 16.2 m³/day (Health Canada 1998)
Dermal absorption fraction: 1

Estimated Exposure to Tartrazine from All-Purpose Spray Cleaner

• Inhalation mean event concentration: 0.025 mg/m³
• Dermal exposure: 0.025 mg/kg-bw per day

Acid Orange 156 was identified to be used in limited types of specialty products that cannot be identified due to confidentiality (Canada 2011). Due to the specialized applications, direct and prolonged exposure to Acid Orange 156 is not expected to be significant for the general population.

CAS 70210-05-8 was identified in a laundry stain remover product based on a foreign MSDS (Reckitt Benckiser 2006). Similar products may exist in the Canadian market; however, based on the recommended use of this product and the expectedly low concentration of the dye, exposure to this substance is considered to be negligible relative to that from textile and leather products.

Amaranth, New Coccine and Tartrazine were identified as ingredients in specialized natural health products and pharmaceutical drugs in Canada (LNHPD 2015; NHPID 2011; NMID 2011). These products are not considered to be significant contributors to exposures of the general population in Canada to these substances.

Amaranth and Tartrazine were identified to be used in cosmetic make-up tattoo inks in Canada based on notifications submitted under the Cosmetic Regulationsto Health Canada, (2011 and 2013 emails from Consumer Product Safety Directorate, Health Canada, to Existing Substances Risk Assessment Bureau, Health Canada; unreferenced). Tattoos are considered to represent a source of exposure, as they are injected into the dermis, just below the epidermal-dermal junction at a depth of 1-2 mm (Lea and Pawlowski 1987; Sperry 1992). Systemic exposure to tattoo colourants partly depends on the amount of ink colourant mobilized into the lymphatic system (Engel et al. 2009), but information on these kinetics is limited for these two dyes. Potential systemic exposure to Amaranth and Tartrazine from inks used in cosmetic tattooing is acknowledged, but not quantified, since exposure of the general population to these substances from foods and cosmetics is more prevalent.

New Coccine was identified in semi-permanent cosmetic makeup tattoo ink and body tattoos. However, exposure is not expected, because such products containing this substance that were previously notified under the Cosmetic Regulations to Health Canada are no longer considered to be present in Canada (2011 and 2013 emails from Consumer Product Safety Directorate, Health Canada, to Existing Substances Risk Assessment Bureau, Health Canada; unreferenced).

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Appendix E: Azo Acid Dyes with Effects of Concern

Some of the Azo Acid Dyes 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.

Table E-1 Note

[a]

Classifications used for carcinogenicity are described in Environment and Climate Change Canada, Health Canada 2014.

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