How much formula does the IEUBK model assume is ingested (in volume/day)?
The IEUBK model assigns lead intakes in micrograns of lead per day (g Pb/day) for food items, rather than calculating intakes from ingestion rates (volume or mass/day) and concentrations. The default lead uptake (from direct tap water consumption) for zero to 12 months of age is 0.37 micrograms per day (g/day), which is based on lead intake from water of 0.80 g/day (0.20 L/day x 4.0 g/L). Assuming a 50% absorption factor, uptake is approximately 0.40 (the actual uptake is slightly less due to non-linear uptake approach). Using 2.0 L/day instead of 0.20 L/day would yield an approximately 10-fold higher intake from water but this is likely to greatly overestimate direct tap water ingestion, as interpreted by EPA for the IEUBK model.
