Chapter 14: Quantitative Risk Assessment
CHAPTER 14 QUANTITATIVE RISK ASSESMENT
Supplemental Questions: The opening quote is by Milton. Who was Milton? John Milton, 1608-74, was an English poet. As a Cambridge undergraduate he wrote poems in Latin and English, including "Ode on the Morning of Christ's Nativity" (1629). He had long planned to write an epic, and in retirement after going blind, he completed his most famous work, Paradise Lost, from which the opening quote is taken. It first appeared in 1667. The story of Satan's rebellion against God and of the expulsion of Adam and Eve from the Garden of Eden, it is generally considered the greatest epic in the English language. [Adapted from The Concise Columbia Encyclopedia © 1989] Who should perform risk assessments at NPL sites, EPA or private parties? EPA Guidance issued September 1, 1993, allows potentially responsible parties (PRPs) to conduct risk assessments under certain limited circumstances, the policy indicates that it is more appropriate for EPA to perform these studies. (see The Hazardous Waste Consultant, May/June, 1994, p. 4.25) [Note to Instructors - For computations of Risk, only one significant figure in the result is appropriate.] 14 -1. Determine the average daily intake and maximum hypothetical intake for all compounds listed in Table 14-3 from dermal contact of soils by on-site workers. Note that some chemicals may required evaluation as both carcinogens and non-carcinogens.
Assume the following parameters: A = skin exposed = 20% = 0.2 x 18,150 cm2 (Table 14-7) = 3630 cm2 DA = dust adherence =0.51 mg/cm2 ABS = skin absorption rate = 6% SM = effect of soil matrix =15% EF = 156 days/year; 2 exposure events per day ED = 1 year (average daily intake) and 70 years (maximum hypothetical intake) BW=70kg AT = 365 days (Non-Carcinogenic) and 25,550 days (Carcinogenic) Chlorobenzene: Average Daily Intake (Non-Carcinogenic):