Laserfiche WebLink
Interested Parties-Use Of Non-Purge Sampling Method <br /> April 23, 1997 <br /> Page 3 <br /> 3 In fine grained sediments (predominately clayey/silty materials) where the <br /> groundwater gradient is relatively flat and wells ars slow to recover (i e., <br /> groundwater monitoring wells routinely►become dry prior to evacuating minimum <br /> purge volumes). These wells can be sampled after groundwater m the monitonng <br /> well recovers to a minimum of 90% of the original groundwater elevation or 24 <br /> hours, whichever is less <br /> 4. Tlie groundwater monitoring well is in use for air spargsag and/or vapor <br /> extraction. <br /> If a leaking UST case is evaluated by Regional Board staff as s low-r:k site or if a responsible <br /> party requests site closure, Regional Board staff may require that a final purged groundwater <br /> samplc(s) be taken from monitoring wells <br /> In areas where mirru apal supply wells have been impacted by gasoline and/or gasoline additives, <br /> purging of groundwater monitoring wells may be requirrd <br /> Groundwater wells with mcasarable free product should be on a regular program of free product <br /> removal If a monitoring wells is determined to contain free product at the time monitoring is <br /> attscipated, it should be bailed to remove any standing free product,purged to remove minimum <br /> well volumes (4-10 casmg volumes), allowed to equilibrate back to pre purged Ievels, then free <br /> proauc. thickness measured and reported <br /> All reports containing the results of groundwater sampling and testing must adhere to QA/QC <br /> protocols and be submitted on this Regional Board's Laboratory Report Forms <br /> As new or updated information becomes available regarding the use and effectiveness of the non- <br /> purge method of groundwater samplmg, changes and/or updates to this document will be made <br /> If you have any generalquestions please contact Mr ]ay Huang at(213)266-7608, or contact the <br /> Regional Board staff assigned to your UST case at (213) 266-7500 <br /> '��/ J� <br /> LAWRENCE P KOLB <br /> Acting Executive Officer <br /> cc: ReVonall Board Members - <br /> Allan Patton,'Underground Storage Tank Program, SWRCB <br /> Regional Board UST Program Managers <br /> Ventura County Local Oversight Program <br /> I h I <br /> Local Implementing Agencies <br /> ' E <br /> RI q c v Pop w ' ow 1lIUSA"q MN O FMand mhom /LHS;V* r d Cm*ft 1MY w"rolow 4&Ad I I! <br /> ' IA"V*YN1+000"002=940*Arid 00 M 4 MM 4r Al DVft iI of PUMW A"ftamm @s Aoril. ' I <br /> � I � <br /> I i <br /> I EI ill I I IE ` i Er <br />