Appendix D: Upper-bounding Estimates of Daily Intake of HBCD by Canadians
| Route of exposure | 0-6 months1, 2, 3 | 0.5-4 years4 |
5-11 years5 |
12-19 years6 |
20-59 years7 |
60+ years8 |
||
|---|---|---|---|---|---|---|---|---|
| Breast fed | Formula fed | Not formula fed | ||||||
| Ambient air9 | 6.0 x 10-8 | 6.0 x 10-8 | 6.0 x 10-8 | 1.4 x 10-7 | 1.1 x 10-7 | 6.0 x 10-8 | 5.0 x 10-8 | 4.0 x 10-8 |
| Indoor air10 | 4.9 x 10-5 | 4.9 x 10-5 | 4.9 x 10-5 | 1.1 x10-4 | 8.2 x 10-5 | 4.7 x 10-5 | 4.0 x 10-5 | 3.5 x 10-5 |
| Drinking water11 | nil | 2.9 x 10-5 | 1.1 x 10-5 | 1.2 x 10-5 | 9.6 x 10-6 | 5.5 x 10-6 | 5.7 x 10-6 | 6.0 x 10-6 |
| Food 12 | 1.0 x 10-1 | nil | 2.6 x 10-2 | 3.9 x 10-2 | 2.8 x 10-2 | 1.6 x 10-2 | 1.4 x 10-2 | 9.4 x 10-3 |
| Soil/ Dust13 | 5.2 x 10-3 | 5.2 x 10-3 | 5.2 x 10-3 | 8.4 x 10-3 | 2.7 x 10-3 | 6.6 x 10-4 | 5.5 x 10-4 | 5.4 x 10-4 |
| Total intake | 1.05 x 10-1 | 5.3 x 10-3 | 3.1 x 10-2 | 4.7 x 10-2 | 3.1 x 10-2 | 1.7 x 10-2 | 1.5 x 10-2 | 1.0 x 10-2 |
1 Human breast milk: 28 µg/kg lipid or 0.084 or 0.1 µg/kg-bw per day based on 3% lipid or human breast milk fat content, body weight of 7.5 kg and 750 g milk consumed per day (Health Canada 2008).
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 The concentration of HBCD in water of 270 pg/L was used to reconstitute formula was based on unpublished data.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 1.8 pg or 1.8 x 10-6µg/m3 from the Canadian and Russian Arctic (Alert, Tagish and Dunai) was selected. (PWGSC-INAC-NCP 2003). Canadians are assumed to spend three hours outdoors each day (Health Canada 1998). Several ambient air measurements were taken across these northern regions of Canada . Other data considered included Hoh 2005, Hites and Hoh 2004, Backus et al 2005, Remberger et al 2004, PWGSC-INAC-NCP 2003, and Abdallah et al 2008a.
10 The median indoor air concentration of 180 pg/m3 or 0.0002 µg/m3 from the United Kingdom was used as surrogate indoor air data for Canadians, n=33 (Abdallah et al. 2008a).
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. For fish, a value of 4.62 µg/kg will be used to capture levels of HBCD in lake trout from Lake Ontario, Canada (Alaee et al. 2004).
13 Highest Canadian dust level in Canadian homes reported by Abdallah et al. 2008b, of 1300 µg/kg dry weight was selected.
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