Adoption of 
Revisions to Ground Water Quality Standards:
Last week the New Jersey Department of Environmental Protection (DEP) adopted amendments to the Ground Water Quality Standards (GWQS), N.J.A.C. 7:9C. The adoption was published in the February 3, 2025, New Jersey Register at 57 N.J.R. 234(a). A courtesy copy of the notice can be found here: adopt-20250203a.pdf.
A phase-in timeframe outlined in the Remediation Standards at N.J.A.C. 7:26D-1.4(b) is applicable to the updated GWQS, allowing a responsible party to complete remediation at a site using the former remediation standards, provided that the remedial action workplan (RAW) or remedial action report (RAR) is approved by the DEP or is certified by a licensed site remediation professional (LSRP) within six (6) months of the adoption of updated standards (i.e., August 3, 2025) if the standard has not decreased by more than an order of magnitude.
The DEP noted that the Soil Leachate Remediation Standards for the Migration to Ground Water per N.J.A.C.7:26D-4.4 will be updated through a Notice of Administrative Change in the near future.
Updates to the Ground Water Screening Levels for the Vapor Intrusion Exposure Pathway:
On February 7, 2025, the DEP released updates to the ground water screening levels (GWSL) for the vapor intrusion exposure pathway for 1,1-dichloroethene, ethylbenzene, and vinyl chloride.
Updated GWSL for the Vapor Intrusion Exposure Pathway:
- 1,1-Dichloroethene = 31 µg/L
- Ethylbenzene = 150 µg/L
- Vinyl chloride = 0.59 µg/L
The DEP has also updated the GWSL for alternate soil texture for ethylbenzene.
The DEP allows for a six-month phase-in period for use of updated GWSL when a RAW or RAR referencing GWSL is submitted within six (6) months of the effective date of the updated GWSL (i.e., August 3, 2025), provided that:
- The RAW or RAR is approved by the DEP or is certified by an LSRP; and
- The remedial action complies with the applicable regulatory timeframes pursuant to the Technical Requirements for Site Remediation at N.J.A.C. 7:26E‐5.
For vapor concern cases, the DEP considers the 60-day mitigation plan [N.J.A.C. 7:26E-1.15(e)2] equivalent to the RAW, and the 180-day mitigation response action report [N.J.A.C. 7:26E-1.15(e)4] the equivalent to the RAR.
For vapor intrusion immediate environmental concern (IEC) cases, the DEP considers the approved Engineered Systems Report Action (ESRA) and IEC Source Control Report equivalent documents to the RAW or RAR, respectively.
For more information including details on the derivation of the GWSL, click here.
Contact
If you have any questions or would like to learn more, please contact:
Michael Metlitz, LSRP
Principal
mmetlitz@whitmanco.com
(732) 390-5858
Posted on February 10, 2025
