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i ! SAAIPLE IDENTIFICATION AND CIIALN-OF-CUSTODY PROCEDURES demansuates the effectiveness of in-Feld cleaning procedures to prevent cross- SOP4 contamination. k I Sample identification and chain-of-custody procedures ensure sample integrity, and document sample possession from the time of collection to its ultimate To minimize the potential for cross-contamination between wells, all well disposal. Each sample container submitted for analysis is labeled to identify the development and water sampling equipment not dedicated to a well is either mob number, date, time of sample collection,a sample number unique to the steam cleaned or properly washed between use. As a second precautionary i 'C mple, any name(s) of on-site personnel and any other pertinent field measure, wells are sampled in order of lowest to highest concentrations as sservations also recorded on the field excavation or boring log. established by available previous analytical data- chain-of-custody fortes are used to record possession of the sample from time of In the event the water samples cannot be submitted to the analytical laboratory collection to its arrival at the laboratory. During shipment, the person with on the same day they are collected (e.g., due to weekends or holidays), the custody of the samples will relinquish them to the next person by signing the samples are temporarily stored until the fust opportunity for submittal either on k chain-of-custody form(s) and noting the date and time. The sample-control ice in it cooler,such as when in the field,or in a refrigerator. t off icer at the laboratory will verify sample integrity,correct preservation,confirm i collection in the proper container(s),and ensure adequate volume for analysis. MEASURING LIQUID LEVELS USING A WATER LEVEL INDICATOR OR INTERFFACE PROSE if these conditions are met,the samples will be assigned unique laboratory log SOP-12 numbers for identification throughout analysis and reporting. The log numbers Field equipment used for liquid-level gauging typically includes the measuring { will be recorded on the chain-of-custody forms and in the legally-required log probe(water level or interface)and a clean product bailer(s). The field kit also book maintained in the laboratory. The sample description,date received,client's includes cleaning supplies(buckets,TSP,spray bottles,and deionized water)to r name,and any other relevant information will also be recorded, be used in cleaning the equipment between wells. IABORATORY ANALI'TIC'AL QUALITY ASSURANCE AND CONTROL Prior to measurement, the probe tip is lowered into the well until it touches SOP-5 bottom- Using the previously established top-of-casing or top-of-box (i.e., In addition to routine instrument calibration,replicates,spikes, blanks, spiked wellhead vault)point,the probe cord(or halyard)is marked and a measuring tape blanks,and certified reference materials are routinely analyzed at method-specific (graduated in hundredths of a foot)is used to determine the distance between the frequencies to monitor precision and bias. Additional components of the probe end and the marking on the cord. This measurement is then recorded on laboratory Quality Assurance/Quality Control program include: the liquid-level data sheet as the"Measured Total Depth"of the well. I I. Participation in state and federal laboratory accreditation/certification When necessary in using the interface probe to measure liquid levels,the probe a programs; is first electrically grounded to either the metal stove pipe or another metal object r 2. Participation in both U.S. EPA PerformanceEvaluationstudies(WS and nearby. When no ground is available, reproducible measurements can be WP studies)and inter-laboratory performance evaluation programs; obtained by clipping the ground lead to the handle of the interface probe case- ' 1 Standard operating procedures describing routine and periodic instrument j maintenance; The probe tip is then lowered into the well and submerged in the groundwater. 4. "Out-of-Control"/Corrcctive Action documentation procedures;and, An oscillating(beeping)lone indicates the probe is in water. The probe is slowly 5. Multi-level review of raw data and client reports. raised until either the oscillating tone ceases or becomes a steady tone. in either case,this is the depth-to-water(DTW)indicator and the DTW measurement is QROUNDNVATER PURGING AND SAhIPI.ING': made accordingly. The steady tone indicates floating hydrocarbons. In this case, SOP-7 the probe is slowly raised until the steady tone ceases. This is the depth-to- Prior to water sampling,each well is purged by evacuating a minimum of three product(DTP)indicator and the measurement of DTP is recorded. A corrected wend well-casing volumes of groundwater. When required, purging will depth to groundwater to account for floating hydrocarbons can be calculated by continue until either the discharge water temperature,conductivity,or pH stabilize using the following formula: to within 10%of previously measured values; and a maximum of ten wetted casing volumes of groundwater have been recovered,or the well is bailed dry. CDTW=DTW-(SP.G x LHT). When practical,the groundwater sample should be collected when the water level CDTW=Corrected depth to groundwater. i in the well recovers to at least 80 percent of its static level. Field measurements, DTW=Measured depth to groundwater. observations and procedures are noted. SP.G=Specific gravity:unweathered gasoline=0.75;diesel =0.80 LHT=Measured liquid hydrocarbon thickness. j The sampling equipment consists of a clean bailer,or stainless steel bladder pump 1 i with a"Teflon"bladder. If the sampling system is dedicated to the well,then the The corresponding groundwater elevation is the difference between a previously bailer is usually "Teflon," but the bladder pump may be PVC with a determined well reference elevation and either the depth to groundwater or the polypropylene bladder. Sample containertype,preservation,and volume depends corrected depth to groundwater. } on the intended analyses. The process of lowering and raising the probe must be repeated several times to The groundwater sample is decanted into each VOA vial in such a manner that ensure accurate measurements. The DTW and DTP measurements are recorded there is no meniscus at the top of the vial. A cap is quickly secured to the top on the liquid-level data sheet. When floating product is indicated by the probes of the vial. The vial is then inverted and gently tapped to see if air bubbles are response,a product bailer is lowered partially through the product-water interface present. If none are present, the vial is labeled and refrigerated for delivery, to confirm the product on the water surface,and as further indication of product under strict chain-of-custody, to the analytical laboratory. Label information thickness,particularly in cases where the product layer is quite thin. Either this should include a unique sample identification number,job identification number, measwement or the difference between DTW and DTP is recorded an the data date.time,and the sampler's initials. sheet as"product thickness." 1 i' For quality control purposes,a duplicate water sample may be collected from a In order to avoid cross-contamination of wells during the liquid-level jwell. When required,a trip blank is prepared at the laboratory and placed in the measurement process,wells are measured in the order of"clean"to"dirty"(where transport cooler. It is labeled similar to the well samples,remains in the cooler such information is available). In addition,all measurement equipment is cleaned during tran"M and is analyzed by the laboratory along with the groundwater with TSP or similar solution and thoroughly rinsed with dcionized water before mples. In addition,a[field blank may be prepared in the field when sampling use,between measurements in respective wells,and at the completion of the days urpment is not dedicated. The field blank is prepared after a pump or bailer activities. # as been either steam cleaned or properly washed,prior to use in the next well, + and is analyzed along with the other samples.' The field blank analysis i Fugro OMR SOPS-4,5,7,t?It994