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Compliance & Closure, Inc Groundwater Sampling Protocol Latest Revision October 2001 conductance) are closely monitored throughout the well purging process and are used as indicators for assessing sufficient purging The purging parameters are measured to observe stabilization to a range of values typical for that aquifer and well Stable field parameters are recognized as indicative of groundwater aquifer chemistry entering the well Specific conductance (conductivity) meters are read to the nearest +10 umhos/cm and are checked daily Temperature is read to the nearest 0 1 F Calibration of physical parameter meters will follow manufacturer's specifications pH will be calibrated daily using two fresh buffer solutions Collected field data during purging activities will be entered on the Well Sampling Field Data Sheet In low yield formations, the well is purged such that the "standing" water is removed and the well is allowed to recharge (Normal field measurements will be periodically recorded during the purging process) In situations where recovery to 80% of static water level is estimated, or observed to exceed a two hour duration, a sample will be collected when sufficient volume is available for a sample for each parameter Attempts will be made so the well is not purged dry such that the recharge rate causes the formation water to cascade into the well In wells where free-phase hydrocarbons are detected, the free-phase portion will be bailed from the well and the estimated volume removed and recorded A groundwater sample will be collected if bailing reduces the amount of free-phase hydrocarbons to the point where they are not present in the well Well sampling will be conducted using one of the aforementioned methods depending on the formation yield However, if free-phase hydrocarbons persist throughout bailing, then a groundwater sample will not be collected Volatile organic groundwater samples are collected so that air passage through the sample does not occur or is minimal (to prevent volatiles from being stripped from the samples) Sample bottles are filled by slowly running the sample down the side of the bottle until there is a positive convex meniscus over the neck of the bottle, the Teflon side of the septum (in cap) is positioned against the meniscus, and the cap screwed on tightly, the sample is inverted and the bottle lightly tapped The absence of an air bubble indicates a successful seal, if a bubble is evident, the cap is removed, more sample is added, and the bottle is resealed If this occurs more than once in a given sample, a new sample will be collected Chain-of-Custody Groundwater sample containers are Iabeled with a unique sample number, location, and date of collection All samples are logged into a chain-of custody form and placed in a chilled ice chest for shipment to a laboratory certified by the State of California Department of Health Services