A review of the Monitored Natural Attenuation (MNA) Guidance Document prepared by stakeholders and NJDEP. This program was held on October 21, 2024 with guest speaker Dr. Jorge Berkowitz
Speaker:
Jorge Berkowitz, Ph.D., LSRP, Private Consultant with over 40 years of environmental consulting experience.
Moderator:
Phil Brilliant, CHMM, LSRP- founder of Brilliant Environmental Services, LLC. Phil is a Board Member/LSRP of the NJ Site Remediation Professional Licensing Board.
“Let Nature Finish the Cleanup”: A Practical Guide to Monitored Natural Attenuation in New Jersey
Key take-aways from the latest CEPS Hot-Topic webinar (Recorded Oct 2024)
When New Jersey’s Site Remediation Program updated its Monitored Natural Attenuation (MNA) Guidance (v2.0), it raised both hope and headaches for LSRPs. During CEPS’s November Hot-Topic session, Dr. Jorge Berkowitz —former NJDEP Assistant Commissioner and veteran consultant—spent an hour unpacking the document and sharing war-stories.
Below is a distilled review for practitioners who need to decide, fast, whether MNA is the right remedy (and how to sell it to DEP).
1 | MNA ≠ “Do Nothing”
- MNA still demands action: a remedial action permit (RAP), a Response Action Outcome (RAO), biennial certifications, financial assurance and annual remediation fees.
- Expect multiple Technical Consultations; DEP will probe your model, your sentinel-well spacing, and your receptor analysis—often more than once.
2 | Three Tiers of Evidence
| Evidence Tier | What DEP Expects to See | Typical Tools |
|---|---|---|
| Primary | Stable/shrinking plume & ≥ 8 quarters of non-increasing data | Iso-contour maps, Mann-Kendall or Sen trend tests, mass-flux calculations |
| Secondary (Organics) | Proof of degradation mechanisms | Electron-acceptor depletion, daughter-product ratios, redox/ORP profiles |
| Secondary (Inorganics) | Proof of sequestration or stabilization | Sorption coefficients, solid-phase mineral ID, geochemical speciation |
| Tertiary | Source differentiation, advanced confirmation | Compound-Specific Isotope Analysis (CSIA), microbial community assays |
Shortcut? No. DEP wants at least two independent lines of evidence—one of them primary.
3 | Receptors First, Receptors Last
Berkowitz drove home the mantra: “No receptor, no problem—until there is.”
- Residential redevelopment, child-care conversions, or downgradient wetlands can all flip a favorable MNA case on its head.
- Sentinel wells must be up-datable; land-use changes can force new well installations or closer spacing.
4 | Mind the “One-Order-of-Magnitude” Rule
DEP will consider residual contaminant concentrations up to 10× the remediation standard—but only if trends are flat or declining and every source has been removed or contained. If a new groundwater standard comes out (PFAS, vinyl chloride), you may need an immediate RAP amendment or technical consultation to keep your MNA remedy alive.
5 | Build Your Bench Early
MNA cases often require expertise well beyond a single LSRP:
- Statistician – non-parametric trend tests, data-gap defensibility
- Risk Assessor – receptor pathway evaluation & public-notification strategy
- Hydrogeologist – flow modeling & mass-flux transects
- Microbiologist/Biogeochemist – redox sequencing, microbial DNA assays
- Isotope Chemist – CSIA for chlorinated solvents or ammonia/arsenic sources
Budget both time and dollars; Berkowitz cited a county landfill case that burned $20 k+ just in CSIA and follow-up consultations before DEP approved the MNA notice.
6 | Use Other States—and EPA—as Precedent
SRRA allows independent professional judgment. Berkowitz recommended quoting:
- EPA’s CSIA and Monitored Natural Attenuation protocols
- The Interstate Technology & Regulatory Council (ITRC) MNA and Conceptual Site Model guidance
- Robust state programs (e.g., Wisconsin, Michigan)
Document why their science applies to your New Jersey site, then weave it into both the RAP and the technical-consult slides.
7 | Communication Is Half the Remedy
- With DEP: Schedule a pre-design technical consult before you start sampling; bring your bench scientists to the call.
- With Clients: Explain that MNA still means long-term costs (sampling, RAP renewal, financial assurance). Forget “set-it-and-forget-it.”
- With the Public: Sign posting and municipal notifications are mandatory once an RI shows a groundwater impact. Prepare fact sheets that are updated when any parameter (well network, standards, land use) changes.
Monitored Natural Attenuation can save millions in active remediation—if you can prove nature will finish what you started.
DEP’s new guidance makes the proof-burden heavier, but also clearer. Use multiple evidence tiers, design adaptive sentinel networks, and keep your legal/technical team tight. Nail that, and your next RAP may end with a coveted “RAO-MNA” stamp instead of a pump-and-treat skid.
The full webinar recording and slide deck are in the video on this page. Upcoming CEPS courses cover child-care/educational facility rules and bedrock plume investigations.