IDEM developed the TPH Fractionation Tool spreadsheet to aid users in implementing the TPH Fractionation Guidance Released by IDEM in June 2006. Users enter the fractions that they receive from the laboratory analysis, enter site specific data when appropriate, and spreadsheet displays site specific values at the bottom of the sheet.
The TPH Fractionation Tool is only as accurate as the data it uses. Ensure that all samples are collected and handled properly, and that all inputs are appropriate for use with the calculator. Review Chapter 8 of the RISC Technical Guide [PDF] to make sure that all data was collected in the proper manner. Failure to do so could invalidate the default closure levels calculated by the TPH Fractionation Tool.
Enter the sample number and date into the appropriate shaded boxes at the top of the “TPH” sheet. This will help us reference the sheet and ensure that the numbers are correctly applied. (All information entered on the TPH Fractionation Tool is used only for reference and is not tracked by IDEM.)
The sheet allows users to enter site specific values for several parameters that are commonly determined during nondefault closures. If you have collected any of this site specific data please enter it into the appropriate yellow box on the left-hand side. Any site specific parameter that you enter into these boxes will require IDEM approval before the values calculated by the TPH Fractionation Tool are accepted. Therefore, remember to attach all information pertaining to these nondefault values to your report.
Note: You do not have to do both Soil and Ground Water Nondefault closure level calculations. For those fractions that have both VPH and EPH analyses, remember to enter the higher of either VPH or EPH into the corresponding fraction on the TPH Fractionation Tool. For those fractions that have both VPH and EPH analyses and both are non-detect (ND), enter 1/2 of the lower of the two NDs.
Enter soil fraction analysis data into the appropriate shaded boxes in the “Soil Fractionation Nondefault Closure Levels Calculator” on the left hand side of the page. Enter ground water fraction analysis data into the appropriate shaded boxes in the “Ground Water Fractionation Nondefault Closure Levels Calculator” on the right hand side of the page. For those fractions which are below the method detection limits, enter 1/2 of the detection limit.
The closure levels that the TPH Fractionation Tool calculates are based on the ratios of each fraction to every other fraction. This means that the calculated values at the bottom of the sheet will change each time you enter a value. Please remember to click or tab out of the final cell so that the sheet will know to update the calculated values. At this point, consider saving or printing a copy of this sheet. You will need to repeat this step for each TPH sample.
This step requires a certain level of professional judgment. You will need to compare the composition of each sample and decide whether they appear to be all from a single source. If all samples appear to be from the same source, compare each value in the “Soil-Derived Nondefault Closure Levels” from each sample and choose the lowest among them. If you want a single nondefault closure level for soils, choose the lower of the maximum cap, soil direct contact or migration to ground water values. You may use the default closure level if the soil nondefault closure level is less than the default closure level. However, if you want exposure pathway-specific (e.g. direct contact or migration to ground water) nondefault closure levels, choose the higher of either the pathway-specific nondefault or default closure levels (not to exceed the maximum cap).
Ground water closure level and hazard index results are automatically calculated and appear in the “Ground Water Nondefault” section.
Submit each TPH Fractionation Tool printout, along with all data needed to validate the inputs into the sheets as an appendix to your report to IDEM.
IDEM recommends that you download and save a copy of the TPH Fractionation Tool to your computer rather than running it from within Internet Explorer. You can download the spreadsheet by clicking the link below and selecting "Save As" from the dialog box that appears.
If you have questions regarding risk-based closure, please see the Contact Risk webpage