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SAMPLE IDENTMCATION AND CHAIN-0F-CUSTODY PROCEDURES demonstrates the effectiveness of in-field cleaning procedum to prevent cross- SOP-4 contammation Sample identification and chain-of-custody procedures ensim ample integrity and document sample possession ftom dedicated to the time of collection to its ultimate To minimize the pi>tetttial For cross-contammalion between wells, all well rent not a well is etcher *sposaI Each sample container submitted for anaivsis is labeled to identify the development and water samplineuig 4 P b number date, time of sample collection, a sample number unique to the steam cleaned or properly washed between use As a second precautionary sample any names) of on-site personnel and any other perwtent field measure, wells arc sampled in order of lowest to highest concentrations as observations also recorded on the field excavation or boring log. established by available previous analytical data- Chain-of-custody ataCham-of-custody forts are used to record possession of the smiple from time of In the event the water sIts cannot be submitted to the analytical laborator) collection to its arrival at the laboratory Dunn& shxpmeat,the person with on the same day they we 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 strived until the fust opportunity for submittal either on ,hain-of-custody form(s) and noting the date and time The sample-control ice in a cooler,such as when in the Feld or in a refrigerator officer di the laboratory will verify sample integrity,correct preservation,confirm t,ollection in the proper container(s),and ensure adequate volume for analysts MEASURING LIQUID I.LVF.LS USING A WATERLEVEL INDICATOR OR INTERFACE PROBE If these conditions arc 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 hqutd-level gauging typically includes the measurng v,ill be recorded on the chain-of-custody forms and in the legally-requimd log probe(water level or interface)and a clean product bailer(s� The field kit also book maintained tit the laboratory The sample description,date received,client's includes cleaning supplies;(buckets,TSP,spray bottles and deuonized water)to name and any other relevant information will also be recorded. be used to cleaning the equipment between wells LABORATORY ANALYTICAL QUAIM ASSURANCE AND CONTROL Prior to measuremeat, the probe up is lowered into the well until it touches SOP-5 bottom Using the previously established top-of-castng or top-of boy (i e In addition to routine instrument calibration. replicates,spikes, blanks, spiked wellhead vault)porn,the probe cord(or halyard)is marked and a measuring tape blanks and certified reference matenals are routinely anaiyzedat method-specific (graduated in hundredths of a foot)is used to determine the distance between the frequencies to monitor precision and buts Additional components of the probe end and the markin on the cared This measurement is then recorded on l-kborauory Quality AssurancelQuairty Control program include the liquid-level data sheet as the "Measured Total Depth"of the well I Panmpauon in state and federal laboratory accreditatton/certtfication When necessary tit using the interface probe to measure liquid levels the prob, programs, is first electrically grounded to either the metal stove pipe or another metal object 2 Partncipatton in both U S EPA Performance Evaluation studies (WS and nearby When no ground is available, reproducible measurements can be WP studies)and inter-laboratory performance evaiusnon programs obtained by clipping the ground lead to the handle of the interface probe case I Standard operating procedures describing routine and periodic instrument maintenance, The probe up is then lowered into the well and submerged in the groundwater Out-of=Control"lCorrecuve Action documentation procedures,and, An oscillating(beeping)tone indicates the probe ism water The probe is slowh Muhl-level review of naw 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 GROUNDWATER PURGING AND SAMPLING made accordingly The steady tone indicates floating hydrocarbons In thus case, SOP-7 the probe is slowly raised imul the steady tone ceases This is the depth-to- 11nor 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 %%ened welkcasmg volumes of groundwater When required, purging will depth to groundwater to account for floating hydrocarbons can be calculated b� Lonnmue unite either the discharge water temperature conductivity or pH stabilize using the following formula. I0 tianthm lo% of previously measured values, and a maxinttun of ten wetted i.asing volumes of groundwater have been recovered, or the well is bailed div CDTW = DTW-(SP G x LHT) When pracucal the groundwater sample should be collected when the water level CDTW -Corrected depth to groundwater 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 e 0 75,diesel -0 80 LHT x Measured liquid hydrocarbon thickness The sampling equipment consists of a clean bailer,or stainless steel bladder pomp welt a Teflon"bladder If the sampling system is dedicated to the well,then the The corresponding groundwater elevation s the difference between a pre.°touch bailer is usually "Teflon" but the bladder pump may be PVC with a determined well reference elevation and either the depth to groundwater or tet. polvpropylenebtadder Sample container type,preservation.and volume depends corrected depth to groundwater on the intended analyses The process of lowering and raising the probe must be repeated several limes it, The groundwater sample is decanted into each VOA vial in such a maniner that ensure accurate measiuemem s; 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 mdtcaud by the probes tit the vial The vial is then inverted and gently tapped to see if au bubbles are response,a product baths is lowered partially through the product-water interface present if none are present, the vial is labeled and refrigerated for dehvery 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 0 cases where the product layer is quite thin Either this should include a unique sample identification number,fob identification number measurement or the difference between DTW and DTP is recorded on the data date time and the sampler's initials sheet as"product thizimes " fur quality control purposes,a duplicate water sample may be collected from a In order to avoid crow-contamntation of v Its during the liquid-level well When requtrcd a trip blank is prepared at the laboratory and placed in the measurement process,wells aro measured in the ort ~`"clean"10"duty"(where 03. ples nsport cooler It is labeled similar to the well samples-remains in the cooler such information is available}. In addition,all meastequipmseanering transport,and is analyzed by the laboratory along with the groundwater with TSP or similarsolution and thoroughly rinsed ecoized water befsaIn addition,a field blank may be prepared in the field when sampling use,between measuremaus in respective wells,and a completion of the day s equipment is not dedicated The field blank is prepared after a pump or bailer activities has been either steam cleaned or properly washed,prior to use in the next well i and is analyzed along with the other samples The field blank analysis rvg^ _--P5 - 5 7 12J1994