Mark A. Lehar, P.Geo. Regional Environmental Lead and Senior Environmental Geologist

Mark A. Lehar, P.Geo. Regional Environmental Lead and Senior Environmental Geologist

Exova Seminar: 15 January 2016 HYDRASleeve TM Focused Sampling - Monitoring Well Sampling Using No Purge HYDRASleeves TM to Characterize and Focus Sampling in a Suspected Laminar Flow Regime Aquifer

What is Laminar Flow? Water flow in which the flow direction remains approximately parallel, without cross currents or eddies Smooth flow at relatively slow velocity Characteristic of groundwater flow Describes natural groundwater flow conditions https://www.dwa.gov.za/groundwater/groundwater_dictionary/index.html?laminar_flow.htm.

Do Laminar Flow Conditions Continue to Exist While Passing Through a Well Screen? Do water particles, imagined as flow lines entering the well screen from the one side, remain approximately parallel with each other within the well screen prior to exiting out the opposite side? or, Do water particles, imagined as flow lines entering the well screen from the one side, become turbulent, mixing with the water column in the well, prior to some water exiting out of the well screen on the other side?

Do Laminar Flow Conditions Continue to Exist While Passing Through a Well Screen? The questions on the previous slide are based around one huge assumption That is, the presumption that the groundwater contamination is confined to a narrower band of sediments, and that the groundwater differences can somehow be identified and measured

Do Laminar Flow Conditions Continue to Exist While Passing Through a Well Screen? If the former (parallel flow lines) were true, we would expect contaminants entrained in the groundwater to BE potentially observable as distinctive layers over some distance in a longer well screen If the latter (turbulent flow) were true, we would expect contaminants entrained in the groundwater to NOT be generally observable as distinctive layering and be more or less ubiquitous through out the water column

Do Laminar Flow Conditions Continue to Exist While Passing Through a Well Screen? Can we answer this set of questions one way or the other?

Do Laminar Flow Conditions Continue to Exist While Passing Through a Well Screen? If the assumption in the first bullet (parallel flow lines) were true, we should be able to characterize a monitoring well vertically within the water column How to go about proving that assumption?

Various Groundwater Sampling Techniques Well volume approach such as Purge and bail Low stress approach such as Low Flow No purge approach such as the use of the HYDRASleeve TM http://bcn.boulder.co.us/basin/waterworks/lust-anat3.htm.

How to Prove it? Again, if the assumption in the first bullet (parallel flow lines) were true, we would expect contaminants entrained in the groundwater to BE generally observable as distinctive layers and we should be able to characterize a monitoring well vertically within the water column We can use the purge and bailer method as a comparison against any other method, as purge and bailer is collecting a composite sample over the entire well screen interval Purging a well seriously mixes the water flowing into the well from and through the well screen, as well as mixing the existing water within the well column with the new water entering the well - turbulent flow

How to Prove it? Generally, the purge and bailer method requires the removal of a minimum of 3 wells volumes on the supposition that, by removing 3 well volumes, the chances are we have fully exchanged the water that existed in the well prior to purging It may or may not have been completely exchanged; however, the water column in the well is now thoroughly mixed - a composite sample

Purge and Bail Sampling Event Remove a minimum of three well volumes Or, remove water until ph, Temperature, and Conductivity are stabilized within 10% Containerize the purge water Disposable sampling tools Depending on the height of the water column, can be expensive to properly handle investigative derived wastes (IDW) for disposal http://ecoenvironmental.com.au/sales/groundwater/ground-water-consumables/bailers/eco-pvc-bailer/.

Purge and Bail Costs Expensive to dispose of IDW (purge water), especially on sites with large well volumes or when sampling occurs frequently Larger quantities of solid IDW, including bailers, rope or twine http://bcn.boulder.co.us/basin/waterworks/lust-anat3.htm Labour costs can also be intensive, when purging three volumes from each monitoring well

Low Flow Sampling Event The point is not to draw down the stagnant water above the screened interval Monitoring purge water parameters Use of variable speed, low-flow sampling pump Minimal IDW related to purge water; however, extensive decontamination of equipment and generation of IDW waters related to decontamination Larger IDW related to tubing disposal, especially related to monitoring wells of greater depth http://www.solinst.com/products/groundwater-samplers/407-bladder-pumps/user-tips/low-flow-sampling.php.

Investigative Derived Wastes Soap Box 1 This assumes that you are disposing of your tubing and decontaminating your pump (whatever type) after use in the monitoring well, even if it is a dedicated system Sidebar Tubing and pumps will retain certain contaminants and potentially accumulate them Food for thought You have non-decontaminated equipment in your monitoring well. The higher concentrations in your plume have passed through your monitoring well. How will you be able to get accurate readings that reflect this, if there is the potential that your equipment is now diffusing compounds back into the groundwater, which had accumulated on your tubing or in your pump?

Low Flow Costs Can be expensive to dispose of IDW (wash and rinse water), associated with decontamination procedures Larger quantities of solid IDW tubing http://www.gwpc.org/sites/default/files/event-sessions/batchelder_chrisine.pdf Labour costs can be intensive, associated with set up and decontamination

Investigative Derived Wastes Soap Box 2 This assumes also that you are disposing of your purge or decon waters Sidebar Dumping purged groundwater, decon waters, or rinse waters onto the ground is transferring contaminants from one media to another and potentially creating another source area in the surrounding soils Food for thought Your firm s general practice for purge water disposal is to dump that groundwater onto the ground. Regardless of whether you have knowledge of the results of prior testing (if any). Is your pollution liability insurance up to date?

No Flow Sampling Event The point is not to sample waters except those in an approximate 5- foot (1.52 m) screened interval Use of 1 m (38 inches = 0.96 m) long HYDRASleeve TM Can sample specific intervals anywhere along the well screen No purging Minimal IDW related to purge water Minimal IDW related to disposable sampling equipment Minimal labour in setup and recovery HYDRASleeve TM recovering free product from monitoring well

How to Prove it? We will use the HYDRASleeve TM at depth discreet sampling intervals, every 5- feet over the length of the well screen Compared against The purge and bailer method, collecting a single sample from the well after purging, which ends up representing the entire well screen interval as a composite sample

Background Confidential Client in the Calgary area Plume origination from gasoline and diesel releases prior to the mid-1980s Monitoring wells are screened between 2 clay units The target unit is a glacially-deposited, sandy silt that varies in thickness

Background The monitoring wells were screened the entire unit interval, no matter the length HYDRASleeve TM samples collected starting from the top of the water column All HYDRASleeve TM samples collected from a monitoring well prior to the purge and bailer sample being collected

Background The Shortest screen length sampled was 10 feet (3.04 m), where the lowest 5 feet were not sampled The longest screen length sampled was 25 feet (7.60 m),where the lowest 5 feet were not sampled The zone available for sampling was potentially affected by both water column height of the unconfined zone and by silt accumulation in the base of the wells

Background Water samples were analyzed for BTEX, PHC fractions F1-F2, PAHs, VOCs, and lead BTEX, PHC fractions F1-F2 because they are standard gasoline and diesel fuel components PAHs (carcinogenic) because they are standard diesel fuel component and are one of the main drivers for the freshwater aquatic life pathway VOCs because two compounds, 1,2 dichloroethane (1,2-DCA) and 1,2- dibromoethane or ethylene dibromide (EDB) are standard leaded gasoline fuel constituents (lead scavengers) that are risk drivers for the inhalation pathway

HYDRASleeve TM Set up so that the length of string or rope sets the HYDRASleeve TM at the base (bottom) of the desired screen interval Measuring string length to base of screened interval Mark string or rope where it will intersect the top of casing such that the HYDRASleeve TM is at the base (bottom) of the desired screen interval

HYDRASleeve TM Set up the HYDRASleeve TM and attach the weight Deploy the HYDRASleeve TM to the appropriate depth HYDRASleeve TM in packaging

HYDRASleeve TM Left: Weight attached to appropriate slot Right: HYDRASleeve TM ready for deployment within monitoring well

HYDRASleeve TM Left: Inserting the HYDRASleeve TM within a flush-mounted monitoring well Right: HYDRASleeve TM deployed within monitoring well

During and After Deployment Deployed the HYDRASleeve TM into the well slowly, trying minimize the disturbance of the water column as little as possible Did not allow the weight to run to the bottom or pull the HYDRASleeve TM to the desired depth minimal disturbance was thought to be ideal Allowed the well equilibrium to stabilize by leaving the HYDRASleeve TM in place for approximately 1 hour, depending on how many wells were targeted for sampling that afternoon In two cases, HYDRASleeves TM were left in the well overnight, due to deteriorating weather conditions The idea was for laminar flow to be able re-establish itself above the HYDRASleeve TM as if the HYDRASleeve TM was not present While waiting, HYDRASleeves TM were set up at other monitoring well locations using the same methodology

HYDRASleeve TM How Does it Work? Check valve pushed down and HYDRASleeve TM fills when recovered at a rate of 1 foot per second http://www.fieldtechsoln.com/products/hydrasleeve.html First water to enter the HYDRASleeve TM is now at the bottom, last at the top

Retrieval Recovery of the HYDRASleeve TM Looks like a regular bailer on recovery; however, it has sampled a specific, depthdiscrete, screened interval and not just the top of the water column HYDRASleeve TM recovering water from monitoring well

http://dilbert.com/strip/2010-10-20

Results Varied One example indicates that almost all BTEX and PHC fraction F1-F2 analytes were higher in the HYDRASleeve TM sample than in the composite sample. Benzene varied by almost 70%

Results Another example indicates that almost all BTEX and F1-F2 analytes were lower in the HYDRASleeve TM samples than in the composite sample. The toluene composite sample was 425% greater than the HYDRASleeve TM sample

Results And yet a third example indicates varied results between the two sampling events

Results 1,2 DCA followed the same pattern (greater concentrations in the HYDRASleeve TM )

Results 1,2 DCA followed the same pattern (lower concentrations in the HYDRASleeve TM )

Results 1,2 DCA followed the same pattern (varied results between the two types of sampling)

Results Laminar flow demonstrated in BH1922 Less then detection in the upper interval Middle and last intervals above guidelines

Results Laminar flow not necessarily demonstrated in BH1921 All samples above guidelines Slight peak in the second interval

Results Laminar flow not demonstrated in BH1929 All samples above guidelines All HYDRASleeve TM samples above composite sample concentrations

Results Laminar flow not demonstrated in BH1929 All samples above guidelines All HYDRASleeve TM samples below composite sample concentrations

Conclusions? Laminar flow confirmed in certain locations The HYDRASleeve TM was able to identify depth-discrete intervals The HYDRASleeve TM did provide better data for the monitoring well in many instances than purge and bailer methods Likely that the unsampled last basal section of well screen may contain the highest concentration of analytes in some instances http://www.financialramblings.com/archives/myra-worth-getting-excited/

Conclusions? Varied results Laminar flow not confirmed in many locations The HYDRASleeve TM did not provide better data for the monitoring well in some instances than purge and bailer methods Other hydrogeologic factors may be present Basal interval unable to be sampled using the HYDRASleeve TM http://www.dailymail.co.uk/health/article-1361679/depressed-thatll-mancession-women-breadwinners.html/

Future Needs? Replicate work under a variety of conditions Make sure the time of sampling is as close as possible between the HYDRASleeve TM sampling and purge and bailer methods Use the compression weight (upper) to compress the HYDRASleeve TM upon deployment and get a sample from the last 5-foot well screen interval https://www.imperial.ac.uk/staff/tools-and-reference/web-guide/tools/site-manager-cms/content-types/banner---bottom-block/

Future Needs? Puppies of course http://www.bbc.co.uk/newsbeat/article/32536857 http://www.livescience.com/38800-abused-puppies-sympathy-adult-victims.html

Questions??

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