We will focus on the "stem and leaf" type SCEM, but there is nothing wrong with the table style. The graphical style is more suited to a public hearing than analysis.
Here is a situation, the Ghost Road lake.
The Ghost Road lake is an old gravel pit that is filled with water. Neighborhood kids swim there in the summer. They also fish there, but seldom catch anything. Both Jonhson's Blueberry Farm and the caretakers of the Cemetery use the water from the lake for irrigation. Birch Acres Subdivision has city water piped in from far way. Gooder school is also on city water, but the school has not been used for several years because the school population has been declining. A contractor wants to buy the gravel pit and surrounding land. She plans to mine gravel for a road being built not too far from there. Before the bank will lend the contractor money, the bank hires an environmental consultant to review the site and assure there is no contamination. The consultant notices the stunted vegetation and takes some soil samples and also samples the water in the lake. The samples indicate that the soil under the stunted vegetation is heavily contaminated with pentachlorophenol (PCP), a wood preservative. The PCP was probably the result of the operations of the contractor who dug the gravel pit. He treated wood on the site. (Go here read a little on pentachlorophenol. It is on the RAIS site and is also one of the defaults in your Level I program.) There is none in the lake water. Now to start you exposure analysis, fill in this table regarding the area where the vegetation is stunted:
| Phase that PCP itself will be in | Solid, Liquid, Gas |
| What media will the PCP be in | Soil, water, vegetation |
| What is the uptake route | Dermal, Inhalation, Ingestion |
| Is PCP water soluble | qualitative |
| What is the log Kow | number |
| What is the Koc | number*(see below) |
| What is the nature of the toxicity | chronic, acute |
* I was saving Koc for a later module. Go to this site ATSDR pull down the pdf for Chapter 6, and scroll down to 6.3 and read about Koc. Mackay's Level I program uses Koc = 0.47 Kow (not log Kow). That is not always true and I don't think it is for PCP. Here is a tool that may be helpful at RAIS Chemical Data Profiles, pick the chemcial off the dropdown menu and find pentachlorophenol. Towards the bottom of the page are useful constants, but note there are different values from different sources.
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