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lie CLEARWATER GROUP, INC ' Groundwater Monitoring and Sampling Field Procedures Groundwater Monitorin* ' Prior to beginning a decontamination area is established Decontamination procedures consist of scrubbing downhole cquipmcnt in an Alconox0 solution wash (wash solution is pumped through any purging pump, used) and rinsing in a first antic of potable water and a second rinse of potable water or dwonized water if the latter is required Any non-dcdicated down hole equipment is decontammated prior to use When using a peivtaltic pump new or dedicated silicon head tube and ' polyethylene tubing is used Piior to purging and sampling a well, the static water level is measured to the nearest 0 0f lett with an electronic watu sounder Depth to bottom is typically measured once per yeai at the request of the prod"( manager, and during Clearwater~ lint visit to a site It historical analytical data are not available, with which to eslabltsh a reliable aider of increasing well ' contamination the water sounder and tape will be decontaminated between each well it floating separate-phase Itydroc.vbons (SPH) are suspected or observed SPH is collected using a clear, open-ended product bailer, and the thickness is mcasuied to the nearest 0 01 feet in the bailer SPH may alternatively he measured with an electronic interface probe Any monitoring well containing a measurable thickness of SPH before or during purging is not additionally purged and no ' sample is collected from that well Wells containing a hydrocarbon sheen are sampled unless otherwise specilted by the piuJcct manager Field observations such as well integrity as well is water level measurements and floating product fhtcknesses tic noted on the Gauging Data/Purge Calculations loan ' Well Puiginc Fach monitoring well to be sampled is purged using either a PVC baiter, submersible primp or i peristaltic pump Physical parameters (pH, temperature and conductivity) of the purge water are monitored during purging activities to assess if the water sample collected is representative of the aquifer If required parameters such as dissolved oxygen, turbidity salinity I etc are also measured Samples are considered representative it parameter stability is achieved Stability is defined as a ch Inge of less than 0 25 pH units less than 10% change in conductivity in micro mhos and less than 1 0 degree centigrade (1 B degrees Fahrenheit) change in temperature Parameters aic measured in a discreet sample decanted train the bailer separately horn the rest of the purge water or in a in-line flowthrough cell Parmmeters are measured at least tour times duimg purging initially, and at volume intervals of one well volume Purging continues until three well casing volumes h ive been removed or until the well completely dewater Wells which dewater or demonstrate a slow recharge may be snnpled aftei Ic,wci than three well volumes have been removed Well purging information is recorded on the Purge Data sheet All meters used to measure parameter are calibrued daily Purge water is scaled, labeled ind stored on site in D O T-appioved 55-gallon drums Atter being chemically prattled, the water rs removed to in appropriate disposal f icility by i licensed waste hauler Gioundwatei Sample Collection Groundwater samples are collected immediately alter purging or if purging rate exceeds well iecharge rate when the well has techargcd to at Icist 90% of its static water level It icchaige is extremely slow the well is allowed to iecharge for at lc ist two hours it practicable, or until sufficient volume has accumulated for sampling The well is sampled within 24 hours 01 putging or rcpurged Samples are collected using polyethylene bailers, either disposable or dedicated to the well Samples may also he collected from the pcirstaltic pump tubing Samples being analyzed for compounds most scmrtive to volatilvation arc collected first Water samples are placed in appropriate laboidtoty-supphcd containers labeled, documented on a ch tin of custody foim and placed on ice in a cooler for transport to a state-certified anilytical laboratory Analytical detection limits match or surpass standards required by relevant local or regional guidelines I Qu ility Assurance Piocecluics To prevent contamination of the samples, CCI personnel adhere to the following procedures in the field A new clean pair of latex gloves are put on prior to sampling each well Wells are gauged, purged and groundwater samples tic collected in the expected oider of increasing degree of contamination based on historical analytical results I All purging equipment will be thoroughly decontaminated between each well, using the procedures previously cicscrihed at the beginning of this section • Duung ,ample collection for volatile organic analysis, the amount of air passing through the sample is minimized This helps pievent the air lrom stripping the volatiles from the water Sample bottles are filled by slowly running the • sample down the side o1 the bottle until there is a convex meniscus over the mouth of the bottle The lid is carefully suewecl onto the bottle such that no air bubbles are prescnt within the bottle It a bubble is present the c ip is removed I C1 FARwAIERGROUP INC (GWS) I revised November R I