One way to estimate maximum acceptable concentrations of toxicants in drinking water or air is to pick an acceptable lifetime risk and calculate the concentration that would give that risk assuming agreed-on exposures such as the residential factors given in Table 10. Find the acceptable concentrations of the following substances: (a) Benzene in drinking water (mg/L), at a lifetime acceptable risk of 1×10−51×10−5 (b) Trichloroethylene in air (mg/m3)(mg/m3), at a lifetime acceptable risk of 1×10−61×10−6 (c) Benzene in air (mg/m3)(mg/m3), at a lifetime acceptable risk of 1×10−51×10−5 (d) Vinyl chloride in drinking water (mg/L), at a lifetime acceptable risk of 1×10−41×10−4