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How to Read IDEM Published Levels Tables - A Practical Guide

IDEM (Indiana Department of Environmental Management) publishes risk-based screening values called “published levels” in its Remediation Closure Guide (WASTE-0046-R2), and picking the wrong column is one of the most common errors consultants make when comparing site data. The tables split soil into three land-use scenarios and groundwater into its own set of values, and each column has a different derivation and a different regulatory meaning. Here is how the structure works and how to apply it correctly.

The Three Soil Columns

IDEM’s soil published levels tables contain three distinct columns. Misreading which one applies to your site can produce a false exceedance or, worse, a missed one.

  • Residential (direct-contact): Derived for unrestricted residential land use, including child exposure assumptions. This is the most protective column and applies to sites where residential use is the current or reasonably anticipated future use.
  • Commercial/Industrial (direct-contact): Derived for adult worker exposure assumptions. Apply this column only when the site has a documented commercial or industrial land use restriction in place or when the current and future use is clearly non-residential.
  • Excavation: This column is not a direct-contact screening level. It represents the concentration above which excavated soil requires special handling or disposal consideration. Compare your soil data to this column when you are evaluating whether soil removed during construction or remediation triggers additional management requirements.

The excavation column is frequently misapplied as a cleanup standard. It is not. It is a soil management threshold for excavated material, not a target for in-place remediation.

Ohio note: Ohio’s Voluntary Action Program (VAP) uses a different structure. Ohio’s CIDARS database contains separate residential and commercial/industrial direct-contact values, leach-based soil values (LBSVs), and migration-to-groundwater values. Do not carry IDEM column logic into an Ohio VAP evaluation.

Groundwater Published Levels

IDEM’s groundwater published levels are separate tables organized by chemical class: VOCs, SVOCs and PAHs, metals, and pesticides/PCBs. The groundwater values are derived for protection of a potable water receptor and are compared directly to dissolved-phase groundwater analytical results.

When you pull a groundwater sample result, compare it to the groundwater published level for the applicable chemical class table. Do not compare groundwater results to soil published levels, and do not compare soil results to groundwater published levels. The pathways are different and the values are not interchangeable.

Vapor Intrusion Pathway

Soil and groundwater published levels address direct-contact and ingestion pathways. The vapor intrusion pathway is evaluated separately using IDEM’s soil gas and indoor air published levels tables. If your site has volatile contaminants, check whether a vapor intrusion evaluation is required under the Remediation Closure Guide before concluding that soil and groundwater comparisons alone are sufficient for closure.

Qualifier Codes Matter

Every value in the published levels tables carries a qualifier code. The most common are:

  • C: Carcinogen-based value, derived at IDEM’s 1E-05 (1-in-100,000) excess cancer risk target
  • N: Non-carcinogen-based value, derived from a hazard quotient of 1
  • S: Soil saturation cap - the value is capped at the maximum soil concentration before a separate liquid phase (NAPL) forms, not a risk-derived number
  • L: Limited - the value is capped at 100,000 mg/kg

When a result exceeds a C-qualified value, you are reporting an exceedance of a carcinogen-based threshold. That distinction matters for how you characterize risk in your report and whether a site-specific risk assessment is warranted.

Checking Current Values

IDEM updates the published levels periodically when EPA toxicity factors or exposure assumptions change. Always pull values directly from the current IDEM published levels tables rather than from a prior report or a spreadsheet carried forward from a previous project. The Indiana R2 walkthrough guide and the published levels standards pages on this site reflect current values by chemical class and medium.

Bottom Line

Match your analytical result to the correct medium first, then the correct land-use column, then check the qualifier. A soil result compared to the wrong column or a groundwater result compared to a soil table will produce a meaningless comparison. For vapor intrusion pathway evaluations, the soil and groundwater tables are not sufficient on their own - consult the soil gas and indoor air published levels tables as well.