The monthly average concentrations for release to sanitary sewers are applicable to the provisions in section 380-4.2 of this Part. The concentration values were derived by taking the most restrictive occupational stochastic oral ingestion ALI and dividing by 7.3 × 10⁶ (ml). The factor of 7.3 × 10⁶ (ml) is composed of a factor of 7.3 × 10⁵ (ml), the annual water intake by reference man, and a factor of 10, such that the concentrations, if the sewage released by the licensee were the only source of water ingested by a reference man during a year, would result in a committed effective dose equivalent of 0.5 rem.