IH Dose-Response Statistics and the Toxic Load

The statistical properties of the dose-response distribution have been extensively reviewed and summarized. An IH dosage traditionally has been expressed as the product of vapor concentration (C) and duration (t), or Ct. The distribution of effective Cts for a homogeneous population is usually log-normal and described by  

When the LCtjo is constant with respect to t, it is said to obey Haber s rule (Haber, 1924). However, Haber s rule is more of an exeeption than a true rule. Thus, a new term, toxic load (TL), has been developed and extensively used in IH toxicology to account for time dependent toxieity. TL is 

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