Appendix E: Upper-bounding Estimates of Oral Exposure to HBCD from Mouthing Flame-retarded Cushion or Upholstered Furniture

Introduction

Consumer product scenario Assumptions Estimated exposure

Oral

mouthing of HBCD flame-retarded cushion or upholstered furniture

Infants 0-6 months old

Default values from Environ (2003a, 2003b) for ingestion from mouthing.

Water solubility of HBCD is 8.6 µg /L, salivary flow rate in a child’s mouth (Vs) is 0.22 mL/min, fractional rate of extraction by saliva (FR) is 0.038, absorption factor by the oral route (AF0) is 0.5, exposure frequency mouthing behaviour (EFmouth) is 9 min/day (Environ 2003a, 2003b), infant body weight of 7.5 kg (Health Canada 1998).

Dose rate

= [WS x Vs x FR x AF0 x EF mouth x 1]/bw

= [8.6 µg/L x 0.22 ml/min x 0.001 L/mL x 0.05 x 0.5 x 9min/day x 1]/7.5 kg

= 5.6 x 10-5 µg/kg-bw per day

5.6 x 10-5 µg/kg-bw per day

Oral

mouthing of HBCD flame-retarded cushion or upholstered furniture

Toddlers 6 months to 4 years of age

Default values from Environ (2003a, 2003b) for ingestion from mouthing.

Water solubility of HBCD is 8.6 µg /L, salivary flow rate in a child’s mouth (Vs) is 0.22 mL/min, fractional rate of extraction by saliva (FR) is 0.038, absorption factor by the oral route (AF0) is 0.5, exposure frequency mouthing behaviour (EFmouth) is 9 min/day (Environ 2003a, 2003b), toddler body weight of 15.5 kg (Health Canada 1998).

Dose rate

= [WS x Vs x FR x AF0 x EF mouth x 1]/bw

= [8.6 µg/L x 0.22 mL/min x 0.001 L/mL x 0.05 x 0.5 x 9min/day x 1]/15.5 kg

= 2.7 x 10-5 µg/kg-bw per day

2.7 x 10-5 µg/kg-bw per day
Introduction

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