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Screening Data Against Risk


For a given set of points, SADA takes the maximum detected value and compares it to the decision criteria when screening data against risk. For human health risk, the data is compared to a Preliminary Remediation Goals (PRGs), which is a function of a given target risk level and land use scenario. To change the target risk (for carcinogens) or target health index (for noncarcinogens), select Configure Human Health and then Target Risk from the Human Health Menu. The default values are 0.000001 for target risk and 1 for target health index. To change the screening statistical approach, see Set Statistics.


To view the screening results, select the contaminant (select Pooled Data to screen all) and media of interest in the secondary toolbar. From the Human Health menu, select PRG Screen Table. This information is displayed in the Screening Results window.






In the example above, Pooled Data was selected to demonstrate all of the toolbar buttons available. These toolbar buttons permit combination views of rads/nonrads/both and carcinogenic/noncarcinogenic/both for the five scenarios of residential, industrial, agricultural, recreational, and excavation.


The Pathway checkboxes allow you to control which pathways are shown. The All pathway reflects exposure to all the currently checked pathways.


If a PRG is exceeded for a particular scenario, the cell value is Yes. The cell is blank if the risk calculation was not available (due to lacking toxicological information) or was less than the PRG. This is useful for quickly identifying contaminants of concern in a risk assessment.


Following are the units for each media. SADA assumes that your sampled values are in the correct units.


Soil and Sediment: mg/kg for nonradionuclides, pCi/g for radionuclides


Surface/Groundwater: mg/L for nonradionuclides, pCi/L for radionuclides


The user should remember that chemical-specific PRGs are initial guidelines (protective of human health and the environment) that are based on readily available. They are not cleanup goals. All chemical-specific PRGs are generally modified utilizing the site-specific data gathered during the RI/FS; however, design staff may be able to streamline the analysis of remedial alternatives by using chemical-specific PRGs early in the decision-making process (before the RI/FS and the baseline risk assessment are completed). A risk-based concentration is considered a final remediation level only after appropriate analysis in the RI/FS and Record of Decision (ROD).


The Screening Results toolbar functions are as follows.



Print – Prints risk results (PRGs, Screenings, Risk).



Copy to File – Copies risk results (PRGs, Screenings, Risk) to file.



Add to Report – Copies results to a report.



Copy – Copies current image to a clipboard. It can then be pasted into most Windows packages.



Export to Excel – Automatically dumps spreadsheet to an Excel file.



Anatype – Displays respectively, the results for radionuclides, nonradionuclides, or both.



Carcinogenic Options – Displays respectively, the results for carcinogens, noncarcinogens, or both.



Risk Scenarios – Displays, respectively, risk results for residential, industrial, agricultural, recreational, or excavation scenarios.