NON-AQUEOUS PHASE OIL SEPARATE PHASE OIL FREE PHASE OIL MOBILE OIL PRODUCT DNAPL NAPL

1. NON-AQUEOUS PHASE OILSEPARATE PHASE OILFREE PHASE OILMOBILE OILPRODUCTDNAPLNAPL Permanent Solution, Yea or Nay

2. The NAPL Issue Sites with significant amounts of separate phase oil may wind their way through the MCP and achieve Permanent solutions without AULs or engineered barriers. Is this reasonable for sites that still have inches of product in monitoring wells?

3. Case Study Newton, #6 Oil, Class C RAO Inches of product left in wells Feasibility study says steam stripping would work, but the 6 figure price is too high. Simple product bailing not evaluated

4. NAPL � A contact hazard until it�s gone. Whether it�s migrating or not, NAPL is a direct contact hazard for human health and/or public welfare. Sometime in the future, might someone dig into it, install a well into it, bring it to the ground surface, or build a foundation into the contaminated capillary fringe?

5. What is our goal? A Permanent Solution, NSR to health, safety public welfare, and the env during any foreseeable period of time. It is reasonable to say that the potential for exposure to oil is a public welfare risk. When can anyone guarantee there will be no future exposure? And, if feasible, our goal is background - the level that would exist in the absence of the release.

6. Regulatory Citations For Pursuing Oil Soil UCL NAPL UCL Hotspot RAPS Phase III Feasibility Feasibility to background RAO and continuing source GW and the need for AULs

7. NAPL � Now you see it � Now you don�t � Even light NAPL can last a long time. The heavier oils degrade more slowly. We don�t have a long history of tracking gasoline and oil releases. At the turn of the century, there were few gasoline stations or bulk oil storage facilities. We can�t easily say that after 50 years all the NAPL will be gone. We know we have worked on petroleum releases that are decades old.

8. Upper Concentration Limits For NAPL, UCLs alone do not stop many sites from submitting a permanent solution. DePastrovich allows a simple division by about 7 for #6 oil in fine sand. So you can have several inches in each well and get a permanent solution. MassDEP guidance now acknowledges that these algorithms are not sufficiently accurate.

9. UCLs - Debunking the � In the Formation� Measurement Reference: EPA 510R96001 How to Effectively Recover Product� Seven formation estimation methods � none account for residual petroleum or heterogeneity of aquifers The methods are not meant to evaluate product thickness to within inches. EPA states that the usability of models to predict free product recovery rates is limited because much model required data is not measurable (ie, relative permeability and capillary pressure relationships)

10. Debunking the formation �continued There is no information about the accuracy or precision of the methods. EPA states that none of the cited methods is particularly reliable under any given set of conditions and it is not usually possible to predict the accuracy of the calculations. Opine - What�s in the well may be more important than what is in the formation because the exposure points, like wells, resemble holes in the formation, i.e, excavations, basements, sumps, water wells, etc.

11. UCLs & NAPL � Interesting by comparison We are concerned about EPH fractions exceeding their upper concentration limits in soil. C9-C18 20,000 mg/kg = 2% C19-C36 20,000 mg/kg = 2% C11-C22 10,000 mg/kg 1% Should we be ten times as concerned about NAPL? NAPL ~ 20 to 40 % of each fraction and 100% in total

12. Case Study Example Commercial Property, #2/#6 oil, several inches of product left in wells after the filing of a Class A2 RAO Indoor air evaluated by modeling from petroleum headspace and Method 2 No indoor air sampling

13. Case Study � Old Dog Petros W. Roxbury � residence � gas UST removed in 1950s, separate phase remains Lawrence, #2 oil, oil broke out 40 yrs ago, from old bakery or cemeteries 1000 ft away. Ft of oil in wells. Oil Co., Newton, oil terminal ca 1930, #1 oil, ceased operation 1961, sep phase in the 1990s

14. NAPL Hotspot Criteria? We don�t have one but�. If there is 0.5 inches NAPL in a well, and nearby well has zero NAPL, is there a Hotspot? If the greatest NAPL thickness is more than 10 times the least NAPL thickness, is there a Hotspot?

15. What is a Source? DEP current Source interpretation � migrating or causing increasing GW, SW or soil contamination or vapors. Consider � Non-mobile oil might be a source of future exposure pathways, because, if the oil does not go to the receptors, the receptors can go to the oil, (i.e, new building construction).

16. Is VPH our only petro concern? How heavy does an oil have to be before it is no longer a potential vapor intrusion concern? Gasoline, #2, diesel, stoddard, naphtha, � likely #4�.?

17. If It�s Feasible To Reduce, Should there be Closure? A site with NAPL may have NSR, for current use, but it may be feasible to recover some quantity of oil on a regular basis. Does feasibility keep you in? If you have 1,000 gallons of oil in the subsurface and you can recover a gallon a week, are you done? If so, what should the recovery feasibility cutoff be?

18. CASE STUDY � Recovery Feasibility Woburn � Gasoline release � UST removal 1981 - Groundwater plume travels a few blocks to several residences New notification in 1999 � 30 mg/l near residences Additional notification in 2008 � odors in residence NAPL recovery systems reportedly collect 10,500 gallons of NAPL from the subsurface (ca ~ 1981)

19. A-2 RAO? Oil in Saturated Zone If oil is not migrating and the avg thickness is < 0.5 inches, there might be no current risk. Is there future potential risk? AULs do not clearly apply to contamination in the saturated zone. Need better AUL MCP language. What about the house with the private irrigation well that gets built next year?

20. Case Study � RAO A-2 Elderly Assisted Living Facility Gasoline and diesel in 9 wells (4� avg) NAPL not in risk assess (used recovery wells only for NAPL thickness) NAPL not in AUL No indoor air sampling Vapor modeling not conservative � max levels not used per 40.0926(3) when data limited Max data thrown out, high surrogates, no re-sampling No soil samples from smear zone

21. Case Study - NAPL Mobility Along Mystic River Cosmetology School Product in wells Oil seeping through walls into classroom Oil may have mobilized when the foundation was excavated / renovated Class dismissed

22. The Old Road to a NAPL Permanent Solution NAPL in wells Avg thickness greater than � inch Use DePastrovich to say < � inch in formation Assert that oil is not migrating (low gw conc, no vapor) Not feasible to recover (oil too heavy, cost high compared to benefit)

23. Permanent Solution Minimum Requirements? For oil, notification & status reports are beneficial to notify and to track status. Class A-2, no notification or status reports Class A-3, A-4 and B-2, AUL for notification, but no requirement for monitoring & status reports By comparison, ROS or Class C require periodic status reports to MassDEP

24. Where DEP is not conservative NAPL exposure assessment not clearly required in human health risk evaluation, for current and future site use Need clear requirement to sample soil in the NAPL smear zone. The need for AULs at product areas should be clearly described. When is NAPL a hot spot? Need discussion. Estimation of NAPL thickness in the formation is not sufficiently accurate. There is no requirement to reduce the amount of product at a site, only a requirement to consider the reduction of the product. Feasibility of removal � we have no criteria When is NAPL a Source material � need discussion

25. This Was Fuel For Thought - The End