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temporarily stored until the first opportunity for submittal
<br />either on ice in a cooler, such as when in the field, or in a
<br />refrigerator at Apex's office.
<br />SOP-4
<br />SOIL CLASSIFICATION
<br />Soil samples are classified according to the Unified Soil
<br />Classification System. Representative portions of the
<br />samples may be submitted, under strict chain-of-custody, to
<br />an analytical laboratory for further examination and
<br />verification of the in-field classification and analysis of soil
<br />mechanical and/or petrophysical properties. The soil types
<br />are indicated on logs of either excavations or borings
<br />together with depths corresponding to the sampling points
<br />and other pertinent information.
<br />SOP-5
<br />SAMPLE IDENTIFICATION AND CHAIN-OF-CUSTODY
<br />PROCEDURES
<br />Sample identification and chain-of-custody procedures
<br />ensure sample integrity as well as document sample
<br />possession from the time of collection to ultimate disposal.
<br />Each sample container submitted for analysis is labeled to
<br />identify the job number, date, time of sample collection, a
<br />sample number unique to the sample, any in-field
<br />measurements made, sampling methodology, name(s) of
<br />on-site personnel, and any other pertinent field observations
<br />also recorded on the field excavation or boring log.
<br />Chain-of-custody forms are used to record possession of the
<br />sample from time of collection to arrival at the laboratory.
<br />During shipment, the person with custody of the samples will
<br />relinquish them to the next person by signing the chain-of-
<br />custody form(s) and noting the date and time. The sample-
<br />control officer at the laboratory will verify sample integrity,
<br />correct preservation, confirm collection in the proper
<br />container(s), and ensure adequate volume for analysis.
<br />If these conditions are met, the samples will be assigned
<br />unique laboratory log numbers for identification throughout
<br />analysis and reporting. The log numbers will be recorded on
<br />the chain-of-custody forms and in the legally-required log
<br />book maintained in the laboratory. The sample description,
<br />date received, client's name, and any other relevant
<br />information will also be recorded.
<br />SOP-6
<br />LABORATORY ANALYTICAL QUALITY ASSURANCE
<br />AND CONTROL
<br />In addition to routine instrument calibration, replicates,
<br />spikes, blanks, spiked blanks, and certified reference
<br />materials are routinely analyzed at method-specific
<br />frequencies to monitor precision and bias. Additional
<br />components of the laboratory Quality Assurance/Quality
<br />Control program include:
<br />Participation in state and federal laboratory
<br />accreditation/certification programs;
<br />Participation in both U.S. EPA Performance Evaluation
<br />studies (WS and WP studies) and inter-laboratory
<br />performance evaluation programs;
<br />Standard operating procedures describing routine and
<br />periodic instrument maintenance;
<br />"Out-of-Control"/Corrective Action documentation
<br />procedures; and,
<br />Multi-level review of raw data and client reports.
<br />SOP-7
<br />HOLLOW-STEM AUGER MONITORING WELL
<br />INSTALLATION AND DEVELOPMENT
<br />Boreholes for monitoring wells are drilled using a truck-
<br />mounted, hollow-stem auger drill rig. The borehole diameter
<br />will be a minimum of four inches larger than the outside
<br />diameter of the casing when installing well screen. The
<br />hollow-stem auger provides minimal interruption of drilling
<br />while permitting soil sampling at desired intervals. Soil
<br />samples are collected by either hammering (with a 140-
<br />pound drop hammer) or hydraulically pushing a conventional
<br />split-barrel sampler containing pre-cleaned two inch-
<br />diameter brass tubes. A geologist or engineer from Apex
<br />Envirotech, Inc., continuously logs each borehole during
<br />drilling and constantly checks drill cuttings for indications of
<br />both the first recognizable occurrence of groundwater and
<br />volatile hydrocarbons using either a PID, FID, or an
<br />explosimeter. The sampler is rinsed between samples and
<br />either steam cleaned or washed with all other drilling
<br />equipment between borings to minimize the potential for
<br />cross-contamination.
<br />Monitoring wells are cased with threaded, factory-perforated
<br />and blank Schedule 40 PVC. The perforated interval
<br />consists of slotted casing, generally with 0.020-inch wide by
<br />1.5 inch long slots, with 42 slots per foot. A PVC cap may
<br />be secured to the bottom of the casing with stainless steel
<br />screws; no solvents or cements are used. Centering devices
<br />may be fastened to the casing to ensure even distribution of
<br />filter material and grout within the borehole annulus. The
<br />well casing is thoroughly washed and/or steam cleaned, or
<br />may be purchased as pre-cleaned, prior to installation.
<br />After setting the casing inside the hollow-stem auger, sand
<br />or gravel filter material is poured into the annular space to fill
<br />from boring bottom to generally one foot above the
<br />perforated interval. A one to two foot thick bentonite plug is
<br />set above this filter material to prevent grout from infiltrating
<br />the filter pack. Either neat cement, containing about five
<br />percent bentonite or sand-cement grout is then tremmied
<br />into the annular space from the top of the bentonite plug to
<br />near surface. A traffic-rated vault is installed around each
<br />wellhead for wells located in parking lots or driveways, while
<br />steel "stovepipes" are usually set over wellheads in
<br />landscaped areas.
<br />After installation, the wells are thoroughly developed to
<br />remove residual drilling materials from the wellbore, and to
<br />improve well performance by removing fine material from the
<br />filter pack that may pass into the well. Well development
<br />techniques used may include pumping, surging, bailing,
<br />swabbing, jetting, flushing, and air-lifting. All development
<br />water is collected either in drums or tanks for temporary
<br />storage, and properly disposed of depending on laboratory
<br />analytical results. To minimize the potential for cross-
<br />contamination between wells, all development equipment is
<br />either steam cleaned or properly washed prior to use.
<br />Following development, the well is allowed to stand
<br />undisturbed for a minimum of 24 hours before its first
<br />sampling.
<br />SOP-8
<br />ROTARY DRILLING MONITORING WELL INSTALLATION
<br />AND DEVELOPMENT
<br />Boreholes for monitoring wells may be drilled using truck-
<br />mounted drill rigs capable of air- and mud-rotary drilling, and
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