Problem
A researcher is conducting a study to determine the lead exposure to preschool age children through the dietary route. She selects a number of children and uses the duplicate diet technique to estimate the mass of lead in their food and the mass of their food for several days. She also collects biological samples from the same children. When comparing her calculated exposure to biomarker data, the biological data seem to show a greater mass of lead when compared to estimates based on the data collected from the duplicate diets. Assuming there is no intake via the dermal and inhalation routes, how might you account for this discrepancy? What measurements would you collect to test your theory?