Figure 3: Curves showing simulated end-of-exposure brain tissue manganese concentrations in monkeys (a) and people (b) as a function of inhalation exposure concentration (mg Mn/m3). Simulated exposures are for 90 days (5 days/week) for either 6 h/day (monkeys) or 8 h/day (human beings). The monkey simulation results at 1.5 mg/m3 (a) are compared with data from Dorman et al. [21] depicted with symbols showing means and standard errors (SEs) from four to six monkeys per time-point. The larger magnitude changes predicted in monkeys compared with humans at higher inhalation exposure concentrations could be due to the saturation of manganese binding sites in the monkey coming from higher manganese concentrations in the diet of the monkeys. Modified from [19].