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    John@SDC
    Sampling around In-Ground Hydraulic Lifts ?
    Topic posted January 24, 2012 by John@SDCMember, last edited January 27, 2012
    886 Views, 9 Comments
    Title:
    Sampling around In-Ground Hydraulic Lifts ?
    Content:

    We recently completed a Phase I ESA for a gas station property with an auto repair shop.  The shop has two in-ground hydraulic lifts that are estimated to be installed in the mid '60s.  Depth to ground water is around 12' bgs.  Due to the age of the lifts we recommended a subsurface investigation.  I was curious as to what kind of scope of work the Commonground members would find most appropriate in this case.

    I was thinking a direct push boring near each lift with samples collected at around 10' and 15' with analysis for TPH, BTEX and PCBs. 

    I would love to hear your thoughts!  Attached is a pic.

    Image:

    Comment

     

    • PhilipZ
      posted January 25, 2012 by PhilipZContributor

      I would add samples at shallower depths.  If you know the depth of the lift pit I would put a sample in that area as well as just under the slab.  I would also expand the analytical.  All kinds of stuff can get dumped or spilled into those pits.

    • Show/Hide Replies
      manno
      posted January 25, 2012 by mannoSuper Contributor

      Depending on the setup, you could have a separate small tank with system also that could need a boring.  I think your analytical regimen is about right, you can probably keep the PCB runs limited just to see if anything shows up. Sometimes mechanics poured waste solvents (i.e., carburetor cleaners) down the unit so you might want to have your lab look for any unknown peaks.

      BTW, some think leaking Hydaulic Lifts do not generate large remediation issues. Here is a pic from a project I recently worked on at a former auto dealership with 15 HLs from the late 50s. This excavation is from just one of the 7 leakers. Some of the excavations exceeded 30 feet bgs. 

      100_0314mod.jpg (3.1MB)
      • Tom Speight
        posted January 26, 2012 by Tom SpeightElite Contributor
         Wow, nice pic:) I always call a job where the hole's big enough that you need survey control for the post-ex samples a large remediation issue!
    • Tom Speight
      posted January 25, 2012 by Tom SpeightElite Contributor

      Depends on the type of lift....some have the reservoir located away from the pistons.  Depthwise, I would aim for just below the bottom of the piston, as a worst-case location. 

    • Matt Fox
      posted January 26, 2012 by Matt FoxElite Contributor

      I suspect that the thinking behind them not being large remediation issues is that typically worst case scenario is a dig and haul during site redevelopment with little or no regulatory agency involvement.  I would imagine that in the majority of cases, the cost of doing a Phase II exceeds the cost of remediation.

    • RobE
      posted January 26, 2012 by RobESuper Contributor

      Since groundwater is so shallow, you may want to consider a couple of push probe / temproary well point locations in the inferred down-gradient location of the shop area.  You might just limit your analytical in the soil to TPH, running expanded tests (PCBs and BTEX+N) where TPH is detected. Target the soil sample for the base of the piston if you know that depth, otherwise fall back to field screening or the soil/water interface.  The groundwater samples could get the full VOC 8260 list along with TPH, with possible expanded testing for PAHs and PCBS (and metals?) if you detect TPH.

    • mkulka
      posted January 26, 2012 by mkulkaElite Contributor

      i would add chlorinated solvent scan.  Parts washers are almost always associated with these types of facilities unless you believe they only used the hoist to replace tires.  I have 

    • Vini
      posted January 27, 2012 by ViniMember

      Hey John,

       
      Great question! I wanted to see what people would do in your place, so I passed your question on to our Commonground Linkedin profile. I got a lot of great replies that bring tons of insight on the matter.
       
      Claude Hine (Owner/CEO at H&LP Environmental Consulting): I would collect samples beginning at 4 feet and go down to a level where I no longer found any indication of contamination. Of course you need to take in consideration the type of soil. If it is sandy, then you must hit clay before you can say it is clean. If it is a heavy clay then the contamination will be slower to move. However you must be sure that the oil plume is not or has not moved down gradient in the soil. I had a buried tank that developed a leak and over the years the leak moved under the building. We had to excavate soil inside the auto repair shop and could not go down deep enough to remove all the contamination. We ended up putting a forced air vacumm system that was operated for more than three years until our state DEC determined it could be shut down. The remediation will depend upon your State's determination when enough is enough.
       
      Christopher Spengler (VP at SCS Engineers) had this detail set of instructions: Where to begin? First of all, you need to understand what type of lift it is (single post, dual post, open-pit fore & aft set up) and the location of the hydraulic oil tank. Sometimes they are aboveground, usually against the back wall of the service bay, but usually they are in the ground near the piston - look for a small fill port. However, some single post lifts (which is what your's looks like unless the second piston is hidden in the photo) don't have tanks and the oil is contained within the casing and then pressured air is applied to the casing. 

      Secondly, you need to investigate whether or not it is the original lift. Looks like there is a sawcut by the wooden barstool. Did this one replace an earlier version? Was the earlier version also a single-post or something different with a larger footprint? 

      Single-post, tankless pistons are the least likely to be susceptible to being a pathway for surface spills. I saw a comment on the commonground page about mechanics pouring solvents into them - well any mechanic with any smarts would do that directly, but was does happen is that when lifts start to leak and fail, they will continue to add hydraulic oil to them until the loss rate vs. cost exceeds their tolerance level, then they'll start putting waste oil in them until they completely fail, and of course, this waste oil may have solvents in it. 

      Other types of lifts are more prone to being pathways for surface spills or "wet floor" cleanup operations (common in the past). The dual post lifts have a pulley box that runs between the pistons (it makes sure the piston rise and fall at the same rate) and the bottom of the boxes always have a hole so that if spills or water gets in, it will drain to the soil. 

      Now of course the open pit, or what I call fore and aft lifts, are the most notorius, especially if built without bottoms to the vaults. However, don't ever think that because there's a concrete bottom that anything was ever stopped from going through. I've seen 18 inches of concrete with enough rebar to make a bomb shelter jealous be saturated with oil all the way through with free product underneath. 

      As for sampling a single post lift, the piston/casing will usually be 8 feet deep wtih a small amount of concrete at the bottom, so a sample between 9 and 10 is appropriate depending on how close you can get (deeper the further away you are). As for 15 feet, with water at 12, you'll be sampling in the saturated zone, so keep that in mind. 

      I always run the highest TPH hit for PCBs. Skip the BTEX only and do a full VOC - 8260 analysis. I'd do a minimum of one VOC for every lift just to be thorough even if I didn't get TPH hits; however, with a single post lift it's highly unlikely that VOCs would be present without TPH, unless it's coming from somewhere else (which is the danger of sampling in the saturated zone). 

      I've done a lot of lifts and all kinds, and yes, espeically with shallow groundwater, you can have substantial releases. They really should be regulated like USTs.

      Hope it helps!
    • geodc
      posted January 27, 2012 by geodcContributor

      Lots of good suggestions above - particularly targeting of the high TPH levels for PCB analyses - I think that is a great suggestion - you could submit the PCB sample with a hold request. Depending on the turnaround time you're getting on TPH analyses, they may or may not have to move forward with the extraction - I don't remember the actual hold times for that off hand. 

      I would add that a method you might consider for screening purposes or sample selection during advancement of borings would be some field screening kits. I've used the Dexsil TPH kits with some success and fairly good consistent comparisons to laboratory results. Of course, sufficient laboratory confirmation is necessary, but these can help to limit investigation costs and generate some real-time results from which you can bracket around hits to help define the extent of contamination, if present.

      I have also been involved with some large excavation efforts associated with hydraulic lifts and also from hydraulic elevators. I haven't gotten quite to 30' on these, but pretty close. Soil texture, in addition to GW, will be an important observation here.