GRO/DRO Changes to Petroleum Remediation Program Guidance, March 7, 2012

The MPCA Petroleum Remediation Section is in process of updating the standard for Gasoline Range Organics/Diesel Range Organics (GRO/DRO). The update is based on a review of current toxicity data and risk from individual compounds. The updated GRO/DRO standard affects Limited Site Investigation (LSI) requirements following tank removal, soil excavation, and contaminated soil treatment and reuse.

The following is a summary of changes:

Unregulated Fill

The MPCA Remediation Division’s policy title PDF icon Best Management Practices for the Off-Site Reuse of Unregulated Fill has been updated and is now effective as follows:

  • The updated organic vapor field screening criterion has been changed from background to less than 10 parts per million (ppm), as measured by a photoionization detector (PID).
  • The updated petroleum-impacted soil GRO/DRO criterion has been changed from less than 10 mg/kg to less than100 mg/kg GRO/DRO by lab analysis.

The Remediation Division's Best management Practices for the Off-site Reuse of Unregulated Fill (BMP) provides a framework for making decisions about the off-site reuse of minimally impacted soils that are not a threat to human health or the environment. By implementing these changes, less minimally impacted soils will be excavated and treated, and greater soil volumes will be reused if they meet the criteria.

Note: The referenced changes above only pertain to a portion of the BMP. Please refer to the BMP for a complete list of criteria, exclusions, and recommendations.

Petroleum Investigation and Soil Excavation

Effective March 7, 2012, the PRP Guidance Document 3-01 "Excavation of Petroleum Contaminated Soil and Tank Removal Sampling" is updated as follows:

  • The GRO/DRO standard used to trigger an LSI in sand/gravel ( item c) is changed from 50 to 100 mg/kg (Refer to Page 2, Section II.B.5, Table 3)
  • This update also changes the upper limit stated in the first bulleted item of Table 3's footnote from 50 to 100 mg/kg.

Contaminated Soil Treatment

The GRO/DRO standard used to signify soil treatment completion will be changed to 100 mg/kg:

  • A new composting general permit will be issued by May 2012.
  • A notice of intent to change the Land Treatment Rule, Minn. R. ch. 7037 will be forthcoming.
  • Thermal treatment is currently rarely used in Minnesota. Any new or reissued thermal treatment permits will incorporate the new 100 mg/kg number.