Dinitro-o-cresol final screening assessment: appendix 1
Appendix 1: upper-bounding estimates of daily intake of DNOC by the general population in Canada
| Route of exposure |
0-6 monthsa Formula fedb |
0-6 monthsa Not formula fed |
0.5-4 yearsc | 5-11 yearsd | 12-19 yearse | 20-59 yearsf | 60+ yearsg |
|---|---|---|---|---|---|---|---|
| Airh | 1.4 × 10-2 | 1.4 × 10-2 | 3.0 × 10-2 | 2.4 × 10-2 | 1.4 × 10-2 | 1.1 × 10-2 | 9.9 × 10-3 |
| Drinking wateri | 4.3 × 10-2 | 1.6 × 10-2 | 1.8 × 10-2 | 1.4 × 10-2 | 8.1 × 10-3 | 8.5 × 10-2 | 8.9 × 10-3 |
| Foodj | 4.3 × 10-2 | not available (NA) |
NA | NA | NA | NA | NA |
| Soilk | 4.0 × 10-4 | 4.0 × 10-4 | 6.5 × 10-4 | 2.1 × 10-4 | 5.1 × 10-5 | 4.2 × 10-5 | 4.2 × 10-5 |
| Total intake | 5.7 × 10-2 | 3.0 × 10-2 | 4.9 × 10-2 | 3.8 × 10-2 | 2.1 × 10-2 | 2.0 × 10-2 | 1.9 × 10-2 |
- 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).
- For formula-fed infants, intake from water is synonymous with intake from food. No data on concentrations of DNOC in formula were identified for Canada.
- 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).
- 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).
- 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)
- 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).
- 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).
- Leuenberger et al. (1988) estimated an ambient air concentration of 0.05 µg/m³ using measured concentrations of DNOC from a rainwater sample (15 nM) taken at Dübendorf, Switzerland, in 1985 and using a reference rain/air partition coefficient (5.6 × 104). Canadians are assumed to spend 3 hours outdoors each day (Health Canada 1998). Data available from which the critical data were selected included Tremp et al. (1993). In the absence of data, the estimated ambient air concentration (0.05 µg/m³) was also used for indoor air. Canadians are assumed to spend 21 hours indoors each day (Health Canada 1998). Ambient air was assumed to be representative of exposure to indoor air, since there was no indication of additional sources of DNOC in indoor environments.
- The detection limit (0.4 µg/L) for DNOC in 19 samples of tap water from Toronto, Ontario, in 2002 was used as a surrogate for the level of DNOC in Canadian drinking water (City of Toronto Water and Wastewater Services Division, 2002a, 2002b, 2002c, 2002d). Data available from which the critical data were selected included Hallberg (1989), City of Toronto (1990), and Spliid and Koppen (1998).
- No quantitative data were identified for concentrations of DNOC in food items. A detection limit of 1000 µg/g was used for a study by Schmidt (1970) that measured DNOC in potatoes. However, this value was not used in the intake estimate due to the age of the study and because DNOC is not expected to contaminate foods based on its application method. Data available from which the critical data were selected included DeVault (1985).
- The Ontario Ministry of Environment and Energy (OMEE 1994) did not detect DNOC in 161 soil samples collected from Ontario. The method detection limit of 100 ng/g was used in the intake estimate as a surrogate for the level of DNOC in Canadian soil. Data available from which the critical data were selected included Webber (1994) and Migaszewski (1999).
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