Toxicological evaluation and limit values for Methyl-tertiary-butyl ether (MTBE), Formaldehyde, Glutaraldehyde, Furfural

8. TDI, limit value in air

For the estimation of a TDI, the LOAEL of 11 mg/kg b.w. per day (5 days/week for 13 weeks) from the study of rats by NTP (1990) is selected. The LOAEL of 11 mg/kg/day is converted to 7.9 mg/kg/day to adjust for the gavage schedule of 5 days/week.

= 0.0008 mg/kg b.w./day

The safety factor SF_I is set to 10 assuming that humans are more sensitive than animals. The SF_II is set to 10 to protect the most sensitive individuals in the population. The SF_III is set to 100 because of using a LOAEL in stead of a NOAEL, because of uncertainties in establishing a LOAEL from the studies, and because the possibility of genotoxic or carcinogenic effects of furfural cannot fully be excluded.

Allocation

The general population is predominantly exposed to furfural from processed food and beverage products. Therefore, only 10% of the TDI is allocated to ingestion of soil and drinking water and 10% is allocated to exposure from ambient air.

Based on the TDI of 0.0008 mg/kg b.w. per day and assuming a daily ingestion of 0.2 g soil for a child weighing 10 kg (w_child), a limit value is calculated:

= 4 mg/kg soil

Based on the TDI of 0.8 mg/kg b.w. per day and assuming a daily ingestion of 2 litres of drinking water for an adult weighing 70 kg (w_adult), a limit value is calculated:

= 2.8 mg/l

8.4 Limit value in air

For the estimation of a limit value in air, a LOAEL of 20 mg/m³ for irritation of eyes and mucous membranes in humans is selected.

= 0.002 mg/m³

The safety factor SF_I is set to 1 as human data are used. The SF_II is set to 10 to protect the most sensitive individuals in the population. The SF_III is set to 100 because of using a LOAEL in stead of a NOAEL, because of uncertainties in establishing a LOAEL, and because the possibility of genotoxic or carcinogenic effects of furfural cannot fully be excluded.