Waste Programs Division: Underground Storage Tanks: Introduction to UST Tier 2 Evaluation Software

The Underground Storage Tank Program supports the use of Tier 2 Evaluations for determining alternative risk-based cleanup levels for soil, and for evaluating whether levels of contamination resulting from releases at leaking underground storage tank sites meet or exceed these alternative Tier 2 standards.

The software which the Underground Storage Tank Program has provided for conducting Tier 2 Evaluations and Reporting is designed for the specific requirements of the Department and A.A.C. R18-12-263.01. The software is not designed to address releases other than leaking underground storage tank systems. It was originally released as ART2 version 1.04. It has been modified to correct specific programming bugs, technical errors, incompatibilities with changes in other programs which the software relies upon, and to update scientific data and Tier 1 standards.

To begin, download the User Manual and read through the computer hardware and software requirements, as well as the installation instructions. Then download the Tier 2 Software to your computer and open from there. Do not try to open from the download dialogue box. This is a self-extracting archive (zip file) of ART2 and its supporting files. WARNING: If you currently have version 1.04 installed on your computer, please delete the ART2_1.0.exe file prior to downloading ART2_1.07. DO NOT delete your files and executable ProUCL version 3.00.02. ART2 is not compatible with the more recent ProUCL version 4.0. If you do not have ProUCL 3.00.02 installed, you may temporarily download it from the U.S. EPA or use the files provided along with the ART2 downloadable package. If you have difficulty accessing version 3.00.02, please contact Jeanene Hanley for assistance, as well as any other questions regarding ART2 or risk assessment.

This version of ART2 does not have an upgraded program of the ADEQ soil leaching model (ADEQ GPL model). This portion of the software may not provide results without run errors. ADEQ advises that you attempt to conduct the soil leaching module and note any messages or errors in the report. ADEQ will provide confirmation analysis. In the near future, ADEQ will make available an Excel-based worksheet version of this model. Alternatively, a stand alone soil leaching model may be used and included with the Tier 2 Evaluation Report. However, assumptions of the model selected must be appropriate with site conditions, parameter values must be documented by source, and copies of measured data provided with copies of program data entry and output sheets.

ART2_1.07 does not provide a Tier 1 test for sites which are currently, or the intended future use will be, where children below the age of 18 years are "reasonably expected to be in frequent repeated contact with soil" [A.A.C. R-18-7-205(E)]. Please contact Jeanene Hanley for assistance with these sites.

Important Changes in ART2_1.07

  • Analytical data which is reported as non-detectable can now be entered as ND. No values should be entered when a chemical is below the laboratory reporting level in the results column.

  • New SRLs values have been entered for Tier 1 standards, which previously had recommended risk-based Tier 1 standards.

  • Updated toxicity factors have replaced older data.

  • Minimum GPL Tier 1 standards (groundwater protection levels) have been added using the same methodology as published in the A Screening Method To Determine Soil Concentrations Protective of Groundwater Quality (ADEQ, 1996).

  • A biodegradation factor of 10 has been applied for indoor air modeling for those petroleum compounds which are typically amenable to biodegradation. These chemicals are benzene, the butyl benzenes, ethyl benzene, methyl cyclohexane, toluene, total xylenes, o-cresol, and carbazole.

  • A lateral attenuation factor of 10 has been applied for indoor air modeling for all volatile chemicals which are located at depths of 15 feet or greater. This is applicable only to leaking underground storage tank releases.

Important Technical Reminders for Using ART2_1.07

  • Only enter laboratory analytical data from soils located within the contaminant plume. Do not enter non-detects from soils collected above, below, or outside the contaminant plume. The location of the contaminant is specific for each chemical, due to fate and transport mechanisms, chemical properties, vadose zone characteristics, and weathering. Use of data only within the contaminant plume is particularly important for calculating a statistically valid representative site concentration (95 percent UCL).

  • Total Petroleum Hydrocarbons is not assessed in this software as a combined group of chemicals, having its own Tier 1 cleanup standard. Rather, it is evaluated by the predominant constituents included in the software. Laboratory analysis for total petroleum hydrocarbons remains an important diagnostic tool for site characterization.

  • It is extremely important that the analytical data entered are results from Method 8260B. Unless the laboratory is certified by Method 8021B to report all of the volatile organic contaminants (VOCs) which are on the target list for 8260B, then Method 8021B does not provide the necessary reporting of chemicals which are regulated substances released from a regulated underground storage tank system. VOC results are required for numerous samples collected within the VOC plume in order for ART2 to be effective in conducting meaningful Tier 2 Evaluations.

  • For all samples collected from 15 feet below surface, please enter the analytical data twice as a 14.9-foot sample and a 15.1-foot sample. This is to compensate for the software's inability to apply the 15-foot sample in statistical analyses for both surficial and subsurface soils.

  • Frequently, analyses are omitted for metals when the released petroleum product is used oil, or heavy fuel oils. Metals are present dependent upon the crude source, but may also be added during formulation or build up from engine wear. Metals should be analyzed for these sites and evaluated in ART2.

  • All releases should have soils analyzed for polycyclic aromatic hydrocarbons (PAHs) by Method 8310, or Method 8270C if the laboratory can achieve the necessary quantitation limits. If concentrations reported for all samples collected from the vertical boring are less than the residential SRL Tier 1 Standard, then soil samples from lateral borings do not need to be analyzed for PAHs. PAH data from the PAH portion of the contaminant plume should be entered in ART2.

  • Do not enter historical data for soils if these soil locations have been resampled (i.e., colocated) and analyzed at a more recent date.

  • It is beneficial to collect soil geophysical data for use in ART2. The software prompts you for these values if you do not use defaults.

  • Always conduct a screening level or preliminary run of ART2 as you collect data from your site. Even incomplete data, and professional judgment to estimate other site conditions, will assist you in determining if additional samples are needed or whether achieving a Tier 2 cleanup Standard is economically suitable.

  • CAUTION: ART2 does not provide for the evaluation of two chemicals which have Tier 1 Standards. n-Hexane and cumene (isopropyl benzene) are typically present in most light fuels. To date, n-hexane has not been a target analyte commonly reported by the 8260B laboratory method for soil samples. However, some laboratories can include n-hexane in this analysis. Please check with your laboratory. n-Hexane is typically not detectable in soils due to its chemical characteristics. Therefore, analysis for n-hexane in soil is not practical unless you have a significant release of gasoline that will not undergo active remediation (e.g., soil vapor extraction), or have high contaminant levels at shallow depths. In this case, analyze for n-hexane in soil vapor samples collected at the site. Cumene, however, is reportable by the 8260B method. If cumene is detected at your site, please compare the maximum site concentration to 92 mg/kg, respectively. If your maximum site concentration exceeds the Tier 1 Standard in soil, please note this in your Tier 2 Evaluation Report and provide the analytical data for the area of concern (AOC) in which they are found. ADEQ will provide the additional evaluation for these chemicals.

Issues Encountered

  • I cannot get all of the pages of the report to print from the Print Manager Option.
    For those pages of the report which you have selected to print that are not, go to that particular tab for that worksheet. At the top tool bar menu, select File. From the drop down menu, select Print. This sheet will then print, and can be included in the complete Tier 2 Evaluation Report.

  • I cannot find a place to enter soil gas data collected from my site.
    ART2 does not have the feature from the J-E model for evaluating indoor air concentrations from soil gas data. The modeling is limited to use of soil solid samples, and groundwater samples.

  • I get errors when attempting to calculate the representative concentration using ProUCL 4.0.
    ART2 is programmed for specific input file formatting and selected output from ProUCL 3.0., UCL for fixed Excel Format. ProUCL 4.0 no longer retains this formatting or file output to specified cells recognized by ART2. You should always print the ProUCL 3.0 UCL statistic results from within ProUCL 3.0 and attach them with the Tier 2 Evaluation Report.

  • Can I use the 95 percent UCL calculated by ProUCL 4.0?
    ADEQ prefers that ProUCL 3.0 continue to be used with ART2. However, ProUCL 4.0 is particularly useful if you have background metals present at your site, and one or more metals have exceeded the Tier 1 Standard. If these conditions are present at your site, please consult Jeanene Hanley, the ADEQ Senior Risk Assessor, for providing this supplemental evaluation outside the context of the ART2 program.

Hardware and Softare Requirements

  • Minimum:
    300 mHz Pentium II
    128 mbytes RAM
    Microsoft Windows 98
    Microsoft Excel Version 8 (part of Microsoft Office 97)

  • Recommended:
    1 gHz Pentium III
    512 mbytes RAM
    Microsoft Windows 2000
    Microsoft Excel Version 9 (part of Microsoft Office 2000)

RBCA Tier 2 Software

Required UST Forms

See Also: