Skip to main content

Risk Assessment of Radon in Drinking Water (1999) / Chapter Skim
Currently Skimming:

F EPA Approach to Analyzing Uncertainty and Variability
Pages 260-268

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 260...
... is calculated by multiplying a series of terms that describe the link between radon concentration in water and the risk to the population using that water. The terms in this link include the radon concentration in water, human exposure levels per unit concentration, radiation dose per unit exposure, and cancer risk per unit radiation dose.
Read the entire page →
From page 261...
... The uncertainty of the mean was modeled as a uniform distribution in the range 0.7-0.9, and the uncertainty in the mode was modeled as a uniform distribution between 0.5 and the sampled mean value. UNCERTAINTY AND VARIABILITY IN RISK POSED BY INHALED RADON GAS In the EPA uncertainty analysis, the basic equation used to calculate inhalation uptake of radon gas is based on both the uncertainty and the variability of the unit dose factor, but the risk factor per unit dose is based on a single value.
Read the entire page →
From page 262...
... ingested) Calculated Uncertainty==> 5th percentile median 95th percentile individual risk Variability 5th percentile 1.7 x 10-8 8.3 x 10-8 3.4 x 10-7 mean 1.3 x 10-7 6.2x 10-7 2.6x 10-6 95th percentile 4.0 x 10-7 1.9 x 10-6 7.9 x 10-6 m=mean value derived from a sample s=standard deviation of a sample n=sample size md=mode of a sample ~=mean value of in(x)
Read the entire page →
From page 263...
... EPA used an inhalation risk factor, RF, of 1.1 x 10-~2 cancer death per person per pCi/L of radon in water and a Cmea-~1 of 246 pCi/L. We can use this equation with N= 1 and UD = 380, which is the median value with respect to uncertainty and the mean value with respect to variability, to estimate the per caput risk within the exposed population.
Read the entire page →
From page 264...
... 5th percentile 17 32 57 mean 250 380 540 95th percentile 800 1300 2000 m=mean value derived from a sample s=standard deviation of a sample n=sample size md=mode of a sample ~=mean value of in(x) in a lognormal distribution c~=standard deviation of in(x)
Read the entire page →
From page 265...
... ~. EF = equilibrium factor (fraction of potential alpha energy of radon progeny that actually exists in indoor air compared with the maximum possible alpha energy under true equilibrium conditions)
Read the entire page →
From page 266...
... Variability 5th percentile 6.5 x 10-7 1.2 x 10-6 2.1 x 10-6 mean 1.2 x 10-5 1.8 x 10-5 2.7 x 10-5 95th percentile 3.9 x 10-5 6.4 x 10-5 1.0 x 10-4 m=mean value derived from a sample s=standard deviation of a sample n=sample size md=mode of a sample ~=mean value of in(x) in a lognormal distribution, c~=standard deviation of in(x)
Read the entire page →
From page 267...
... 267 RF (risk factor, This factor has lifetime risk of uncertainty only RF=LN(~, Is' ) ~ = cancer death per ln(2.83 x 10~)
Read the entire page →

Key Terms

  • lognormal distribution
  • risk factor
  • radon gas
  • radon progeny
  • radon concentration

  • lifetime risk
  • risk posed
  • cancer death
  • dose factor
  • individual risk

  • indoor air
  • monte carlo
  • transfer factor
  • probability distributions
  • progeny inhaled

  • unit risk
  • represent value
  • value ranges
  • inhaled radon
  • unit radon

  • population risk
  • uncertainty analysis
  • water includes
  • carlo simulations
  • basic equation

  • alpha energy
  • epa uncertainty
  • inhalation risk
  • outcome distribution
  • radiation dose


    • This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
    More information on Chapter Skim is available.