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4. "Out-of-Control"/Corrective Action documentation "Teflon,"but the bladder pump is PVC with a polypropylene bladder. In
<br /> procedures;and, general and depending on the intended laboratory analysis,40-milliliter
<br /> glass,volatile organic analysis(VOA)vials,with"Teflon"septa,are
<br /> 5. Mufti-level review of raw data and client reports. used as sample containers.
<br /> The groundwater sample Is decanted into each VOA vial in such a
<br /> SOPS manner that there is no meniscus at the top of the vial. A cap is quickly
<br /> HOLLOW-STEM AUGER MONITORING WELL INSTALLATION secured to the top of the vial. The vial is then inverted and gently
<br /> AND DEVELOPMENT tapped to see if air bubbles are present. If none are present,the vial is
<br /> labeled and refrigerated for delivery,under strict chain-of-custody,to
<br /> Boreholes for monitoring wells are drilled using a truck-mounted, the analytical laboratory. Label information should include a unique
<br /> hollow-stem auger drill rig. The borehole diameter will be a minimum of sample identification number,job identification number,date,time,type
<br /> 4 inches larger than the outside diameter of the casing when installing of analysis requested,and the sampler's name.
<br /> well screen. The hollow-stem auger provides minimal interruption of
<br /> drilling while permitting soil sampling at desired intervals. Soil samples For quality control purposes,a duplicate water sample is collected from
<br /> are collected by either hammering(with a 140-pound drop hammer)or each well. This sample may also be analyzed or put on hold at the
<br /> hydraulically pushing a conventional split-barrel sampler containing pre- laboratory. When required,a trip blank,prepared at the laboratory,is
<br /> cleaned 2-inch-diameter brass tubes. A geologist or engineer from placed in the transport cooler. It is labeled similar to the well samples,
<br /> Apex Envirotech,Inc.,continuously logs each borehole during drilling remains in the cooler during transport,and is analyzed by the laboratory
<br /> and constantly checks drill cuttings for indications of both the first along with the groundwater samples. In addition,a field blank may be
<br /> recognizable occurrence of groundwater and volatile hydrocarbons prepared in the field when sampling equipment is not dedicated. The
<br /> using either a portable photolonizatlon detector,flame ionization field blank Is prepared after a pump or bailer has been either steam
<br /> detector,or an explosimeter. The sampler is rinsed between samples cleaned or properly washed,prior to use in the next well,and is
<br /> and either steam cleaned or washed with all other drilling equipment analyzed along with the other samples. The field blank analysis
<br /> between borings to minimize the potential for cross-contamination. demonstrates the effectiveness of the in-field cleaning procedures to
<br /> prevent cross-contamination.
<br /> Monitoring wells are cased with threaded,factory-perforated and blank
<br /> Schedule 40 PVC. The perforated interval consists of slotted casing, To minimize the potential for cross-contamination between wells,all
<br /> generally with 0.020-inch wide by 1.5-Inch long slots,with 42 slots per well development and water sampling equipment not dedicated to a well
<br /> foot. A PVC cap may be secured to the bottom of the casing with is either steam cleaned or property washed between use. As a
<br /> stainless steel screws;no solvents or cements are used. Centering secondary precautionary measure,wells are sampled in order of least
<br /> devices may be fastened to the casing to ensure even distribution of to highest concentrations as established by available previous analytical
<br /> fitter material and grout within the borehole annulus. The well casing is data.
<br /> thoroughly washed and/or steam cleaned,or may be purchased as pre-
<br /> cleaned,prior to installation. In the event the water samples cannot be submitted to the analytical
<br /> laboratory on the same day they are collected(e.g.,due to weekends or
<br /> After setting the casing inside the hollow-stem auger,sand or gravel holidays),the samples are temporarily stored until the first opportunity
<br /> fitter material is poured into the annular space to fill from boring bottom for submittal either on water ice in a cooler,such as when in the field,
<br /> to generally 1 foot above the perforated interval. A 1-to 2-foot thick or in refrigerator at Apex's office.
<br /> bentonite plug is set above this fitter material to prevent grout from
<br /> infiltrating the filter pack. Either neat cement,containing about SOP-8
<br /> 5 percent bentonite,or sand-cement grout is then tremmied into the ROTARY DRILLING MONITORING WELL INSTALLATION AND
<br /> annular space from the top of the bentonite plug to near surface. A DEVELOPMENT
<br /> traffic-rated vault is installed around each wellhead for wells located in
<br /> parking lots or driveways,while steel"stovepipes"are usually set over Boreholes for monitoring wells may be drilled using truck-mounted drill
<br /> wellheads in landscaped areas. rigs capable of air-and mud-rotary drilling,and continuous coring
<br /> and/or drilling with tri-cone roller or fixed-blade drag bits. Generalty,
<br /> After installation,the wells are thoroughly developed to remove residual rotary drilling is used when more conventional hollow-stem auger
<br /> drilling materials from the wellbore,and to improve well performance by drilling either is or becomes infeasible. Various drilling fluids(mud or
<br /> removing fine material from the fitter pack that may pass into the well. air),used to keep the borehole from caving and to remove drill cuttings,
<br /> Well development techniques used may include pumping,surging, are chosen according to the nature of the soils and/or geologic
<br /> bailing,swabbing,jetting,flushing,and air-lifting. All development formations expected to be encountered as well as the monitoring
<br /> water is collected either in drums or tanks for temporary storage,and program. Samples may be collected directly from cores. A geologist or
<br /> properly disposed of depending on laboratory analytical results. To engineer from Apex Envirotech,Inc.,continuously logs each boring
<br /> minimize the potential for cross-contamination between wells,all during drilling and checks returned drill cuttings for indications of bath
<br /> development equipment is either steam cleaned or property washed the first recognizable occurrence of groundwater and volatile
<br /> prior to use. Following development,the well is allowed to stand hydrocarbons,using either a portable photoionization detector(PID),
<br /> undisturbed for a minimum of 24 hours before its first sampling. flame ionization detector,or explosimeter. All drilling equipment is
<br /> either steam cleaned or washed between borings to minimize the
<br /> SOP-7 potential for cross-contamination.
<br /> GROUNDWATER PURGING AND SAMPLING
<br /> Frequently,hollow-stem augers are used to drill and sample to either a
<br /> Prior to water sampling,each well is purged by evacuating a minimum minimum depth or auger refusal. In such cases,the augers may be left
<br /> of three wetted well-casing volumes of groundwater. When required, in place as temporary surface casing,with the center plug removed and
<br /> purging will continue until either the discharge water temperature, drilling/coring carried out through the augers. Alternatively,a shallow
<br /> conductivity,or pH stabilize,a maximum of ten wetted-casing volumes conductor casing,or surface casing,may be set by drilling to a desired
<br /> of groundwater have been recovered,or the well is bailed dry. When depth with a large-diameter bit,then setting the casing and proceeding
<br /> practical,the groundwater sample should be collected when the water with the drilling/coring. After total drill depth(TD)is reached,the
<br /> level in the well recovers to at least 80 percent of its static level. borehole may be logged by geophysical means or hydraulically tested.
<br /> If casing is not set to the bottom of the borehole,the lower portion of
<br /> The sampling equipment consists of either a"Teflon"bailer,PVC the hole may be grouted or backfilled accordingly. The borehole may
<br /> bailer,or stainless steel bladder pump with a"Teflon"bladder. If the be drilled out(reamed)as necessary with a large-diameter bit.
<br /> sampling system is dedicated to the well,then the bailer is usually
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