Limitations on dose estimation.

The process of estimation of dose at a target organ from the measurements of environmental concentration of potentially hazardous agents is theoretically examined. The analysis of the estimation process suggests that the design of any study which aims to find the health effects of an agent or to construct a dose-response relationship from environmental measurements must be fully scrutinized to see whether a representative dose is tractable from such measurements made on the agent or extrapolation from a set of known effects at high dose levels is feasible and desirable.