[A theoretical study on the maximum permissible concentration of mercury vapor (author's transl)].

Mercury concentrations in the brain of man exposed to mercury vapor at or around the maximum permissible concentration were estimated by two mathematical models using informatins obtained from human and animal experiments. (formula: see text) Ac=concentration in the brain, C=concentration in air, V=ventilation volume, T=daily exposure time, R=proportion of mercury vapor retained after a single inhalation, D=proportion distributed to the brain, W=weight of the brain, b=elimination constant of mercury vapor in the brain, d=elimination constant of mercuric mercury in the brain, c=proportion of oxidization of elemental mercury in the brain. Model 1 is composed from a simple hypothesis that mercury vapor retained in the brain takes a single elimination coefficient, and in Model 2, a modification of Model 1, the part of elemental mercury retained in the brain is oxidized and thus has a different biological half-time from elemental mercury. During exposure to mercury vapor at the concentration of 0.05 mgHg/m3, estimated concentrations in the brain by Model 1 do not exceed a hypothetical critical concentration in the brain of 1.0 micrometerHg/g tissue but the estimated concentration by Model 2 exceeds this level.