Homework
Remember the PCP contaminated site from Submodule 5A and the SCEM on page 6 of 5A? The SCEM indicates a possible 17 different completed exposure pathways. Assume that on the site where the vegetation is stunted, the average soil contamination with PCP is 500 mg/kg and that this is the concentration of the dust from the site. And the contamination in the yards of Birch Acres subdivision and the graveyard is 50 mg / kg. Also that PCP is a non-carcinogen (for the purposes of this exercise).
For homework, I want you to consider the exposure via inhalation of kids in Birch Acres, exposure of future gravel pit workers via direct dermal contact at the site, and custodians of the cemetery (who only work at that site when they dig graves) by direct dermal. Develop an Intake for each of those classes of receptors and exposure routes.
Here is a resource site from the DoE: The beginning of this page has a good review of ideas we have covered earlier. Look at Topic 4, Land Use Descriptions, Equations, and Technical Documentation, but don't try to link to 4, just scroll gently. That section starts a compilation of risk in risk scenarios of which three might apply to the receptors in our example. Scrolling through Topic 4, you will see great cartoon pictures, followed by long incomprehensible equations. For now, just try to find equations similar to what you have been working with in this Submodule. Pick through them and find the best fit to the exposure pathways and receptors listed above. Most will not fit exactly. You will notice some different equations for exposure to radiation; pCi stands for pico-Curies and is a measure of radiation. You will not need any of those radiation equations.
Do this on an Excel spread sheet. Label each of the three receptor classes on the left then under each label the six main parameters, from the list in 6A page 2: C, CR, EF, ED, BW and AT. Then go to the DOE site and find the relevant equation and their parameters. You will see that CR and EF and sometimes others have been modified to accommodate specifics of particular routes. On your spread sheet you will need to relabel those. Finally, place the values you think are important in those spaces. On the next page there is a copy of a Excel spreadsheet I did for the contaminated blueberries eaten by distant sources and my notes.
Your last step will be to compute an intake rate for each of the three cases. The main point of this exercise is to get you to explore a few of the intake equations and the type of information that is available. You might start by looking at the equations from the RAGS A which are referenced earlier in the Submodule and the parameters from Exposure Factors Handbook because you will need some information from those sources. The DoE site will give you both an equation and some parameters for most of the cases. If you can't find the information, I want you to think and make a reasonable assumption - just be sure to explain your assumptions.
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