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� r CDecontamination is completed at each location on the measuring tape.A spray bottle with alconox soap and a spray bottle with clean rinse water are used to complete this task. If the measuring tape appears to be very contaminated then we will return to the decontamination trailer and scrub the spool in a large stainless steel barrel of soap and water and then it is thoroughly rinsed_ I /1 Once all the wells have been sounded,the appropriate purging equoment is then determined to Lcomplete the necessary tasks required at each purging/monitoring point In the case of dedicated purging and sampling systems this is not an issue. However,the dedicated C system at the well head is inspected for its integrity and operational status to produce a representative sample. Dedicated systems typically are air bladder pumps,direct submersibles and Waterra inertia pumping units. Priorto beginning the monitoring well purging and sampling event,all field equipment used during the event is steam cleaned and stored inside of individual clean storage containers. Ntrile gloves are worn always duringthe time the monitoring and sampling tasks are completed. Aftercompletingthe sampling tasks at each sampling point the gloves are changed and disposed of so that no possible outside or cross contamination can come into contact at the next sample location At each sample point they are also changed routinely if there is any question of possible outside contamination contact has occurred.No purging,monitoring or sampling equipment will be used at the next sample point until each piece has been thoroughly cleaned and decontaminated. C Next,each one of the monitoring wells is purged at a steady continuous flow nate(if possible). Our goal is to not over-stress or draw down the water formation within the well casing. We want a smooth lateral flow through the well screen interval. Dependent on geological conditions,the ability of the well to recharge is usually unpredictable,however the techniques used for purging can skew C the field monitoring results and possibly the laboratory results. Each well is purged for a proposed minimum of three calculated casing purge volumes. Purge volumes are determined by subtracting F, the standing water level from the top of casing from the total depth The standing water column is IL then multiplied by the correct multiplier that is relevant to the well casing diameter. i.e.(8533 feet depth to water- 100.00 feet total depth=14.67 feet standing water column X.1632 for a two inch well or.6528 for a four inch well=2.39 gallons of standing water would be inside a g 2"well casing.) The multiplier is changed accordingly in respect to the well casing diameter. Del-tech has many different types of purging and pumping systems in our inventory. Each ofthese systemshas a unique characteristic that will perform the purging tasks with the greatest effectiveness for each wells unique condition. The type of system used during these monitoring events will be logged on the Del-Tech monitoring well field log. Occasionally,one type ofpurging system will not do the job as well as another type of purging device. In the case of dedicated systems this �I determination of proper purging devices is usually not an issue and has been predetermined. However,dependent on the exposure to the naturally occurring elements or chemical consistuants at any given sampling location,dedicated units have shown to be vulnerable to the elements. In some rcases the dedicated unit has become almost a sacrificial anode and been destroyed. to those L Standard GeoteOperating P Support Standard Operating Procedures / Groundwater Monitoring 2006 G E