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This document presents the field sampling plan (FSP) in support of investigation and closure of the listed solid waste management units (SWMUs) at Camp Stanley Storage Activity (CSSA), Texas. This FSP describes specific closure activities anticipated to be necessary to satisfy regulatory requirements for closure of the SWMUs identified in this plan. The CSSA EPA identification number is TXD2210020739, and its Texas solid waste registration number is 69026.

This document was prepared by Parsons Engineering Science, Inc. (Parsons ES) of Austin, Texas, for CSSA under the U.S. Air Force Air Mobility Command (AMC) Contract F11623-94-D0024, delivery order RL 17.

This field sampling plan describes the scope and procedure for field sampling activities and is organized into five sections. The first section includes details of planned field operations. Environmental sampling procedures are presented in Section 2. Section 3 details field measurements. Section 4 describes field quality assurance/quality control (QA/QC). References are in Section 5.

1.1 - Field Operations

The primary purpose of this field investigation is to obtain data sufficient to assess the closure potential of each of eight low priority units, thirteen medium priority units, and seven high priority units located at CSSA. Approximate SWMU sites are shown on the Site Location Map. The work plan (WP) details the work to be performed and presents location maps of each SWMU. The project objectives will be accomplished by conducting a field investigation under procedures which are outlined in this FSP. Each SWMU will be located and mapped, followed by surface collection of soil samples for analyses and evaluation. If surface soils are found to be contaminated, or subsurface waste management actions are suspected, or geophysical anomalies are identified through a surface geophysical survey, shallow borings will be drilled. If water is present in the shallow borings, groundwater samples will be at the unsaturated-saturated interface collected for specific chemical analysis. If contamination is suspected, a grab sample of groundwater may be collected. If these samples indicate contamination, borings will be completed as monitoring wells and groundwater samples collected. In addition, soil gas surveys will be conducted in specified areas.

The field procedures described in this section were developed to incorporate standard procedures, such as those in the U.S. EPA Compendium of Superfund Field Operations Methods (EPA, 1987), the Air Force Center for Environmental Excellence (AFCEE) Handbook for the Installation Restoration Program (IRP) (AFCEE, 1993), and Parsons ES�s Field Services Manual, (Engineering-Science, 1992).

Standard forms will be used for documentation of borehole logging, monitoring well construction, most field sampling operations, and equipment calibration. Bound field logbooks will be used to record daily field activities and events. Procedures for logbook documentation are presented in Section 4.4 and examples of standard forms to be used are located in Appendix A.

1.1.1   Site Reconnaissance, Preparation, and Restoration Procedures

The SWMU sites at CSSA were categorized as low, medium, and high priority sites based on past waste management practices. The minimal field investigations for the low priority units will include mapping, geophysical surveys, and sampling at least three surface soil locations. However, unless field conditions indicate otherwise, these investigations will probably not include subsurface investigation or water samples. Geophysical surveys and at least three soil borings will be completed at all thirteen medium priority sites. Three samples will be taken from each soil boring area; at surface, middle, and total depths. If groundwater is encountered in a particular soil boring, the saturated/unsaturated interface in that boring will be sampled. If the sample is discovered to be contaminated, the boring will be completed and sampled as a groundwater monitoring well. The procedure and criteria for well development is described in Section 1.2.2. Additional closure activities may be performed for the remaining high priority SWMUs based on schedule and budget constraints.

The exact locations of boreholes will be determined in the field by Parsons ES personnel prior to investigation. Underground and aboveground utility lines, buildings, and natural features will be considered in choosing these drilling locations. The drilling locations will be submitted to CSSA and AFCEE for approval prior to initiating any investigative efforts. Ambient air conditions will be monitored for organic vapors before and periodically during drilling to ensure that no health and safety concerns exist at the site. Plugging the boreholes is further discussed in Section 1.3.

A temporary field office will be located at CSSA to store field team equipment and recharge project equipment. A fire extinguisher and first aid kit will be available in the field office and in each field vehicle for transport to each site where field activities are being performed. All other personal safety equipment such as protective clothing and respirators will be stored in the field office. All hazardous chemicals will be stored in a fire-resistant cabinet. The Health and Safety Plan (HASP) for Closure of SWMUs at Camp Stanley Storage Activity, Boerne, Texas may be referred to for further information on health and safety issues (Parsons ES, 1995).

Decontamination of equipment used during the investigation will take place at decontamination areas set up specifically for this purpose. Decontamination fluids will be containerized at each site until laboratory results for that site are received and are evaluated for the possibility of contamination. If analytical results indicate contamination, the decontamination fluids will be characterized for appropriate disposal. Contaminated fluids will also be containerized and subsequently characterized for disposal in accordance with applicable laws and regulations. Parsons ES will assist CSSA in planning the disposal of waste materials and fluids which cannot be treated at CSSA. Section 1.7 of this plan outlines the management of investigation-derived wastes (IDWs).

Efforts will be made to minimize disturbance at all field activity sites. All trash associated with this investigation will be removed from the site and all landscaped sites will be restored to their original conditions.

1.1.2   Surface Geophysical Surveys

The surface geophysical surveys will be conducted using a Geonics EM-31 electromagnetic instrument. In the electromagnetic induction (EMI) method, the electrical conductivity of a geohydrologic section is measured by transmitting a high-frequency electromagnetic field into the earth, producing eddy currents that generate secondary electromagnetic fields which can be detected by a receiver. The eddy currents are induced in the earth by an aboveground transmitter coil, and the resulting secondary electromagnetic fields are coupled to an aboveground receiver coil. Thus, EMI measurements do not require direct ground contact as is the case for resistivity measurement, allowing surveys along traverse or specific areas to be performed rapidly.

1.1.2.1    Determination of Electromagnetic Measurement Locations

Electromagnetic conductivity measurements are generally collected along a grid system. The area covered by the grid and the spacing between grid nodes is site-specific and depends on the project objectives. The maximum grid spacing will be no larger than 100 feet by 100 feet, with data points spaced every two feet along each grid line. Gridlines will be spaced every 20 to 50 feet and will be site-specific. CSSA and AFCEE personnel will approve all proposed grids prior to surveying activities.

The first step is to establish a base, or background, station to measure the naturally occurring electromagnetic properties in the site vicinity. The base station will be selected to represent naturally existing subsurface conditions at the site.

Background readings will be taken periodically during the electromagnetic conductivity survey. The readings will be taken daily before the survey begins, at 2-hour intervals during the survey, and at the end of each day's work.

The most recent portion of the electromagnetic conductivity survey will be repeated if the base station readings vary by more than 20 percent. The base station readings should be stable unless electronic interference is occurring or unless heavy rains increase the soil saturation.

Data will be continuously recorded with a digital data logger (polycorder). For each survey line, the line number, starting point, direction of traverse, and increment of measurement will be entered in the polycorder. This information will also be recorded in the field logbook, as well as the ending point. Cross-checks will be made between the logbook and polycorder for each line to ensure correct identification and settings. If a discrepancy is found, the survey team will return to the last verified grid point or line and continue forward with the survey.

Data will be collected in both quadrature and in-phase modes. The quadrature mode is generally more useful for investigating the limits of disturbed soil as it allows detection of subtle differences in areal ground conductivity. The in-phase mode is less sensitive and generally more adept for use in locating metal objects.

The data will be plotted upon completion of the survey and before demobilizing to determine if the survey data is valid and the coverage of the site is complete. Additional data will be obtained as needed to complete the survey.

1.1.2.2   Equipment Functional Checks

The range switch should be set at the 30  milliSiemens/centimeter (mS/cm) position for these tests. If the reading is off scale, i.e., greater than 30 mS/cm, refer to the note at the end of this section.

1. Set the mode switch to the "Comp" position and adjust the meter reading to zero using the coarse and fine compensation controls.

2. To check the phasing of the instrument, set the mode switch to the "Phase" position. Note the meter readings and rotate the coarse control one step clockwise. If the meter reading remains the same, the phasing is correct. Return the coarse control to its original position (one step counterclockwise); no further adjustment is necessary.

A phase adjustment is required if there is a difference in the meter readings taken before and after the coarse control was rotated one step clockwise. With the coarse control in its original position, adjust the phase potentiometer about one-quarter turn clockwise and note the new meter reading. Rotate the coarse control one step clockwise, take a reading, and return the coarse control to its original position. If the difference in meter readings has decreased, repeat the procedure using a further clockwise adjustment until rotating the coarse control one step clockwise produces no change in the meter reading. However, if the difference in meter readings was increased, the phase potentiometer should be rotated in a counterclockwise direction instead, and the procedure described above repeated until there is no change in the meter readings. Always remember to set the coarse control back to its original position. This can be confirmed by setting the mode switch in the "Comp" position and checking to see that the meter reads zero. If it does not read zero, repeat steps (a) and (b).

3. To check the sensitivity of the instrument, set the mode switch to the "Comp" position and rotate the coarse control clockwise one step. The meter should read between 75 and 85 percent (22 to 26 mS/cm) of full-scale deflection (inside black mark). It is unlikely that the sensitivity of the instrument will vary; however, it may be useful to record the actual meter reading for comparison at a later date.

Return the coarse switch to its original position; the instrument is now ready to make ground conductivity measurements. Note that when conducting the functional tests over ground of higher conductivity than 30 mS/cm, the range switch should be set at the appropriate level. No matter what level the range switch is in, the readings taken in (c) should still be between 22 and 26 mS/cm.

1.1.2.3   Instrument Calibration

The electromagnetic conductivity meter is internally calibrated at the factory. However, the following instrument checks should be made daily before the electromagnetic conductivity meter is used.

1. Select the transmitter coil tube using the identifying labels on the tubes. Align with respect to the main tube. Insert and clamp the coil in position.

2. Check the battery condition, plus and minus, by setting the mode switch (mode selector switch) to the "Oper" position and the range switch to the "+B" and "-B" positions, respectively. If the needle remains inside the "Batt" mark on the meter, the batteries are in good condition. Otherwise, replace the batteries with a fresh set of C-size alkaline batteries.

3. Check the zero readings by setting the mode switch to the "Oper" position and the range switch to the least sensitive position of 1,000 milliSiemens/ cm. This minimizes any external noise interference while checking the zero position. If a zero adjustment is required, adjust the DC zero control located under the front panel to obtain a zero reading. To do this, the battery pack must be removed to gain access to the controls.

4. Align and connect the receiver coil tube to the main frame tube. The instrument is now ready to proceed with the functional checks.

1.1.3   Soil Gas Survey Methods

A summary of the soil gas survey methods, from determination of sampling locations through sample analysis and quality control procedures, is presented in the following subsections.

1.1.3.1   Determination of Soil Gas Sampling Locations and Sample Depth

Depending on the size of the SWMU to be investigated, soil gas samples will be collected on 20 to 100-foot grid intervals which will be extended off of existing soil gas and geophysical grids from previous investigations or staked out in new areas of concern. If new gridlines are to be established, CSSA and AFCEE concurrence will be obtained. The grid systems used will be shown on individual site base maps.

To determine the optimum sampling depth at each site, depth profiles will be attempted. Because of the variable nature of the soil cover at each site and the proximity of the underlying limestone to ground surface, sampling at a uniform depth is not practical. Consequently, probes will be generally driven to the bedrock-soil interface or until refusal.

1.1.3.2   Soil Gas Sampling Method

Samples will be collected by manually driving a decontaminated �-inch stainless steel hollow sampling rod to the selected depth with a pneumatic hammer. The sampling rod will then be backed a few inches out of the ground allowing the detachable point to drop off the sampling probe and exposing a void space of the formation. Soil vapors will then be pulled from the soil through the probe into a Tedlar bag using a portable vacuum pump. The soil formation around the sample rod will be purged for at least three probe volumes prior to sample collection.

The procedure for collection of soil gas samples using Tedlar bags is as follows:

1. After purging is completed, the desiccator will be opened and a Tedlar bag connected to the line from the sampling probe with a piece of Tygon tubing. The top of the desiccator is then put back in place.

2. The vacuum pump will withdraw soil gas from the ground.

3. After a sample has been collected, the bag will be removed from the desiccator, and the valve on the bag closed.

The samples will then be transported to the field gas chromatograph (GC) temporarily located at CSSA for analysis. Samples will be analyzed within four hours of collection.

After sampling, probes will be decontaminated for use at another location. Decontamination procedures consist of washing off the probes with Alconox and water, rinsing and allowing the probes to air dry.

1.1.3.3   Soil Gas Sample Screening

An initial screening of the soil gas samples will be performed in the field by scanning the exhaust from the vacuum pump with an explosimeter for oxygen content. The vacuum pump is a rotary vane, oil-less, and 1/6 horsepower model equipped with a vacuum regulator. An Industrial Scientific Corporation, Model HMX 271 will be used to measure the levels of oxygen and explosive gases in the soil gas.

The explosimeter will be calibrated daily for oxygen readings by setting the readout to 20.9 percent oxygen when held in ambient air. For oxygen and LEL measurements, the explosimeter has a stated accuracy of + 1.2 percent oxygen by volume in the range of 5-30 percent and + 10 percent of the actual concentrations in the range of 30-100 percent of the LEL.

1.1.3.4   Soil Gas Analytical Equipment

Soil gas samples will be analyzed with an HNu model 321 GC equipped with an electron-capture detector (ECD) and a photoionization detector (PID) with a 10.2 eV light source. A Spectra-Physics model 4400 dual-channel integrator will be used to plot the chromatograms, to measure the size of the peaks, and to compute compound concentrations.

The ECD contains a radioactive nickel-63 foil with a source strength of 5 millicuries. This source decays by emitting beta particles at a maximum energy of 0.063 million electron volts (MeV), which are absorbed by less than 1 milligram per centimeter squared (mg/cm²) of aluminum. There is no discernible radiation from the nickel-63 source external to the detector chamber and no hazard as long as the chamber integrity is not violated. A current leak test certification will be maintained on site. The shipment of the ECD to and from the site shall comply with DOT regulations. The instrument is operated under a general license for radioactive sources.

The chromatographic column used for analysis is a 12-foot long, 1/8-inch diameter stainless steel packed column containing 3 percent OV-101 Chromosorb W-HP packing material with a 100/120 mesh particle size. The OV-101 Chromosorb W-HP is the column packing material that performs the actual separation of compounds. This column was selected for use since it is able to separate the compounds targeted for analysis and allows for a relatively rapid analysis time.

1.1.3.5   Target Compounds and Calibration

Soil gas samples will be analyzed for select volatile organic compounds (VOC) including trichloroethene (TCE), tetrachloroethene (PCE), and cis and trans-1,2-dichloroethene (DCE) because these compounds have been detected in Well 16 and other monitoring wells. In addition, soil gas samples will also be analyzed for benzene, toluene, ethylbenzene, and total xylenes (BTEX) to test for fuel contamination.

In addition to the above compounds, the total volatile hydrocarbon concentration will be reported. The total hydrocarbon concentration is defined as the sum of all peak areas on the chromatogram through ortho-xylene minus any halocarbon peak areas, divided by the toluene response factor and the injection volume. Halocarbons are defined as chlorine, fluorine, or bromine substituted hydrocarbons and include compounds like TCE and PCE.

Calibration standards will be performed at the beginning and end of each day to determine the response factor and retention time for each of the target compounds. The standards will be injected directly into the gas chromatograph in the same manner as the soil gas samples.

1.1.4   Borehole Drilling and Soil Sampling

Borings will be drilled through unconsolidated soils using hollow-stem augers. The boreholes drilled will have an 8-inch diameter to allow for well installation should groundwater be encountered. Borings will be continuously sampled during augering using a decontaminated sampling device (i.e. Shelby tube, split spoon) advanced beyond the lead auger to collect undisturbed soil.

At the point of auger refusal, i.e. bedrock is encountered, borings will be completed by air rotary drilling. During air rotary, samples will be collected using a 5-ft or 10-ft core barrel. The length of the core barrel will be determined by the on-site scientist/engineer based on sample recovery and schedule considerations.

Some lithologies, such as clay infillings, soft marl layers, and solution cavities, have low recovery using air core sampling techniques. Therefore, the on-site scientist/engineer may choose to cease air coring if these lithologies are encountered, and collect samples from the layer using a split spoon or Shelby tube to enhance recovery.

Soil borings will be drilled to a depth of at least 5 feet deeper than observed waste management activity, or if no waste management activity is evident, 5 feet into bedrock. Borings may be advanced deeper if field screening indicated gross contamination at this depth, or if the presence of groundwater dictates advancement for proper monitoring well construction.

If water is not encountered, the borings will be grouted to the surface with a mixture of type I or II Portland cement, bentonite powder, and water in the proportion of 8 gallons of potable water, 4 pounds of bentonite, and 94 pounds (one sack) of cement. Grout will be pumped from the bottom of the borehole upward through a tremie pipe. These procedures are further detailed in Section 1.3.

Additives, except for water, will not be used for dust control or cuttings removal. Only Teflon tape, or other lubricants approved by AFCEE will be used on the threads of downhole drilling equipment. Commercial products such as Well Guard, Pure Gold Lube, and Green Stuff, are commonly used for drilling operations. A material safety data sheet for each product that may be used will be provided to AFCEE and CSSA prior to drilling. Additives containing lead or copper shall not be used. The least amount of lubricant necessary shall be applied. These precautions shall preclude residual groundwater sample contamination caused by the lubrication of the downhole equipment.

Actual depths of samples taken for chemical analyses will be at the discretion of the qualified on-site scientist/engineer based on field screening methods, presence of absence of groundwater, total depth of boring, and sample recovery. As many as three soil samples may be collected from each borehole, including samples from the total depth of the boring, at the depth indicated by field screening to be the most contaminated, and at the depth just above and at the saturated zone, if groundwater is encountered. In addition, a soil sample may be collected from the surface (0 to 2 ft bgl) for risk assessment purposes. Soil samples taken for chemical analyses will be described using Unified Soil Classification System (USCS) terminology. All soil samples will be described by a qualified scientist or engineer with respect to lithology, grain size, color, moisture content, etc. (see Section 1.1.6). In addition, any discoloration of the soil samples or odors detected will be recorded on the boring logs. After they have been lithologically described on the boring logs, the soil or rock samples will be placed into appropriate sample jars and properly labeled. A geologist will be present and responsible at each operating drill rig for logging samples, monitoring drilling operations, recording water losses or gains and groundwater data, preparing the boring logs and well diagrams, and recording the well installation procedures. Each geologist will be responsible for only one operating rig and will have, as a minimum, a copy of the WP, SAP, and the HASP. They will also have on-site their own 10X hand lens, weighted steel tape, water level measuring device, and the necessary materials to decontaminate the water level measuring device.

The sample containers will be placed on ice in coolers until delivered to the laboratory. Samples will be shipped to the laboratory on a daily basis. Summaries of the analytical methods, sample containers, and preservatives are presented in Section 2.2.

During drilling activities, if gross contamination or unexploded ordnance is encountered, STOP WORK. Examples of gross contamination are liquid volatile waste or sludges, buried drums or canisters, or other field evidence that the field team leader deems as gross contamination. The field condition will be discussed with the Parsons ES project manager, AFCEE and CSSA prior to resuming work. Because none of the SWMUs undergoing investigation have a history of use as ordnance demolition or storage, and geophysical surveys will be conducted prior to any drilling actions, unexploded ordnance would be highly unlikely to be encountered during drilling. However, if unexploded ordnance is suspected, the field conditions and materiels found (if any) will be discussed with AFCEE, CSSA, and unexploded ordnance specialists before any field work resumes.

1.1.5   Field Screening During Drilling and Sampling

Sampling operations will be monitored using an HNu PID to detect the presence of VOCs. The Hnu PID, which will be calibrated at least once daily according to the manufacturer's specifications, will be used as an indicator of the presence of significant organic vapor levels. During drilling events, samples will be chosen for organic vapor headspace analysis based on instrument scanning and/or qualitative indications of contamination. A representative portion of each sampling interval will be placed in a glass jar for headspace analysis. The analysis will be conducted by securely placing oil-free aluminum foil over the top of the jar, setting the jar aside for 10 to 20 minutes at 70�F to 90�F to allow volatiles to escape from the soil sample into the head space, and then inserting the probe of the HNu through the foil to measure the level of VOCs in the headspace of the jar. Organic headspace analysis results will be recorded on the drilling log.

In addition to VOC monitoring, an HMX 271 combustible gas indicator will be used to monitor the lower explosive limit (LEL) in work areas. During field activities that can potentially generate sparks, such as drilling, the breathing zone and the air in and around the borehole or well will be periodically monitored with the HMX 271 combustible gas indicator. Monitored readings will be recorded in the field logs.

During drilling operations, headspace analyses will also be periodically conducted on drill cuttings. If soil cuttings are suspected to be hazardous (based on HNu measurements greater than 50 parts per million (ppm), odors, or discoloration), they will be placed in proper containers and characterized by toxicity characteristic leaching procedure (TCLP) for volatile organics and metals, as outlined in Section 2.1.6. Containerized hazardous waste will be removed from the field into an appropriate CSSA storage and handling facility and plans will be made for proper disposal. All removed drums will be labeled in accordance with the CSSA hazardous waste identification system.

1.1.6   Lithologic Descriptions

Lithologies will be described by a geologist using materials retrieved with a barrel sampler, cuttings during rotary drilling, or core samples. Lithology will be logged at 0.5-foot intervals and at each change of lithology.

Lithologic descriptions of unconsolidated material will consist of the predominant lithology in capital letters, followed by the predominant mineral content, secondary components and estimated percentage of sand, color, particle angularity, plasticity, significant structural or textural features, consistency (cohesive soil), density (non-cohesive soil), coherency, moisture content, and depositional environment and formation. Dimensions of the predominant and secondary particle sizes will be recorded using the metric system. Descriptions of clastic deposits will include symbols of the Unified Soil Classification System (ASTM D2487-85). Classification of color will follow Munsell color charts.

Lithologic descriptions of consolidated materials will follow standard professional nomenclature. Special attention will be given to describing fractures, vugs, solution cavities and their fillings or coatings, and any other characteristics affecting permeability. A sample drilling log form is in Appendix A. The vertical scale of the field logsheets will be appropriate for the level of detail noted.

To determine appropriate slot size and filter pack distribution for monitoring wells to be installed, a field sieve analysis will be performed during Stage II actions on soils from a site at which it is likely that a groundwater monitoring well may be required. Should groundwater be detected during drilling, the geologist shall ascertain from the soil or rock cuttings if the groundwater is most likely located within soils or rock formations. If the groundwater is within soils, and it is possible that a monitoring well might be required at the site in accordance with Section 3.1.1.2 of the Work Plan, then the geologist will use sieve analysis as described to perform a field check on the grain size distribution within the soils. If the groundwater is found within limestone rock, then no sieve analysis is necessary.

The field sieve analysis will be performed in accordance with Groundwater and Wells (Driscoll, 1986). A portion of soil will be taken from the interval containing groundwater and allowed to air dry. The sample will be measured in a 100-mL graduated cylinder, then sieved by hand using 3-in sieves. Sieve sizes that should provide an adequate distribution for the clays and gravels expected at CSSA are US Standard Sieve Numbers 16 (0.047-inch sieve opening diameter for gravel or coarse sands), 40 (0.017-inch diameter for fine sands), and 100 (0.006-inch diameter for smaller particles). The volume of material retained on each sieve is measured via the cylinder. The volumes are divided by the total volume of the sample, and the resulting percentages plotted versus grain size on an arithmetic graph. To exclude the entrance of the majority of fine-grained soils into the wells, an appropriate filter pack size will be estimated at three to four times the 70-percent retained size of the sieved sample. The well screen slot size will be estimated to retain approximately 90 percent of the filter pack.

Because the sieve analysis is a field screening, the resulting estimation may indicate a filter pack size or well screen slot size that is not obtainable from typical well driller vendors, e.g., the filter pack or slot size would have to be a special order. Such orders are costly and are not necessarily warranted under field checks of sieve analysis. Therefore, should the above field analysis result in estimation of a filter pack size or screen slot size that is not obtainable through typical well driller vendors, the filter pack or screen slot size will be estimated at the closest size that is both appropriate for the soil type and cost-effective insofar as being obtainable from a vendor within a few days of the order.

The drilling log will also list the following information:

1.2 - Well Construction and Development

1.2.1   Monitoring Well Construction

The installation of necessary wells will begin within 1 week after determination, via chemical analysis of all soil samples, that the unsaturated-saturated interface in a boring contains contaminants. No breaks in the installation process will be made until the well has been grouted. In case of unscheduled delays such as personnel injury, equipment breakdowns, sudden inclement weather, well installation will continue as soon as possible.

All monitoring wells installed during this investigation will have an 8-inch diameter borehole. Except for those wells installed in soils instead of limestone as described in Section 1.1.6 and whose filter pack and screen slot are determined through sieve analysis, well construction materials, will consist of 2-inch schedule 40 PVC flush threaded casing with a minimum length of 5 feet of 0.020-inch factory-slotted screen. All PVC will conform to the ASTM standard F-480-88A or the National Sanitation Foundation standard 14 (plastic pipe system). All connections will be flush-jointed and threaded, and the well bottoms will be capped. Casing will extend from the top of the screen to approximately 2.5 feet above ground surface. All screens, casings and fittings will be new. No glues, solvents, or thread compounds will be employed during screen and casing installations.

Parsons ES will design the wells by the guideline outlined in the AFCEE IRP Handbook.

The well screen and casing will be centered and suspended about one foot off the bottom of the borehole as the annular space is being filled with sand pack. The pack will consist of washed and bagged well-rounded 20/70 mesh sand (predominantly siliceous). The pack size was selected to accommodate the slot size and the smallest anticipated particles that can practically be retained by pack and slots.

The filter pack will be placed from the bottom of the borehole to approximately 2 feet above the screen slot. The filter pack will be poured very slowly into the well annulus from the surface. If depth is greater than 15 feet, filter pack will be pumped. The volume of filter pack used must equal the calculated volume for the appropriate length of well annulus. If the pack materials have bridged, measures such as surging the well must be taken to enhance settling of the filter material. The top of the sand will not extend to less than 4 feet bgl to allow adequate space for the seal and cement grout. The filter pack will be placed into the first water-bearing unit encountered in the borehole.

A 100 percent sodium bentonite seal will be placed above the sand pack to a minimum thickness of 2 feet to form an adequate seal above the pack materials. The bentonite seal will be hydrated in the hole with potable water (when the seal is above the water table) to ensure that the seal is developed before cementing operations begin.

Cement grout with bentonite gel will be placed from the top of the bentonite seal to 2 feet below ground surface. The grout will be mixed in the proportion described in Section 1.3. The grout will be placed in the annulus by the tremie pipe method, with the bottom of the tremie pipe set near the top of the bentonite seal.

1.2.2   Monitoring Well Development

Monitoring wells will be developed as soon as possible but no sooner than 48 hours after internal mortar collar placement has been completed. All fluids used during well construction will be removed during development. Development will be accomplished with a pump and will be supplemented with a bottom discharge and filling PVC bailer (for sediment removal) (EPA, 1992). A 5-ft stainless steel lead will be attached to the bailer. Clean nylon rope will be used to raise and lower the bailer and the stainless steel lead. Before well development begins, the water level will be measured within 0.01 foot using a graduated water level indicator (e-line) with respect to a reference point permanently marked on the north side of the top of the casing. Any conditions which may affect water levels shall be recorded in the field log. The measurement device will not alter sample composition.

During development, water will be removed throughout the entire water column by periodically lowering and raising the pump intake. Well development will continue until the following conditions are met:

The well bore (or pore) volume is defined as the volume of submerged casing, screen and filter pack (assuming a 30  percent porosity). If recharge rates are slow and the required volume cannot be removed in 48 consecutive hours or the water remains discolored or excess sediment remains, the AFCEE and CSSA points-of-contact will be contacted for guidance. A minimum of five additional pore volumes will be removed when excess sediment remains.

Specific conductance, pH, and temperature measurements will be taken once before, twice during, and once after development. These measurements will be recorded on the development logs. If pH and conductivity stabilize during the removal of the final two pore volumes, the well will be considered to be developed. The pH, conductivity, and turbidity meters will be calibrated daily. Calibration procedures are further described in Section 3.

Development water will be containerized pending laboratory analysis. Water deemed to be hazardous will be handled and disposed in accordance with all applicable laws and regulations as described in Section 1.7 of this FSP.

Well development data recorded on the well development logs include:

Water removed from a well during development will not be counted towards any pre-sample purging requirements.

1.2.3   Monitoring Well Purging

Using the static water level, well casing diameter, and total depth of the well, one well casing volume is calculated and recorded. Purging is performed by removing 3 to 5 well casing volumes from each monitoring well. The water is removed via a decontaminated bailer or pump and placed in a drum with a locking lid pending laboratory analysis. If the water is determined to not be contaminated by laboratory analysis, it will be poured out onto the ground inside the SWMU. The bailer rope should not be allowed to touch the ground during sampling. For every 5 gallons removed, measurements of pH, temperature, and specific conductivity are collected and recorded on the groundwater purging and sampling form. The measurements of groundwater must be within �0.5 pH units, �1�C, and �10% u mhos/cm per container. When at least three subsequent measurements are within 10% of each other, it is indicative that the water is removed from the aquifer rather than from the well casing. The water level is then allowed to recharge to at least 80% of the static water level or to recharge for at least 16 hours, whichever occurs first, before sampling. The well will be sampled within 24 hours of purging.

1.3 - Borehole Abandonment Procedures

Soil boreholes will be abandoned to prevent migration of substances between geological formations or from the surface. All soil borings will be plugged as soon as possible after completion of use in a period not to exceed 3 days. Abandonment information will be included on the drilling log form. A sample of this log is in Appendix A.

Once approved, the borehole to be abandoned will be sealed by grouting from the bottom of the boring to ground surface. Grout will be pumped into the borehole until undiluted grout flows from the boring at ground surface. The grout will be mixed in the following proportions: 94 pounds (one sack) neat Portland type I cement to 100 percent sodium bentonite powder with approximately 8 gallons of approved water. The bentonite will be added after the required amount of cement is mixed with water. A mud balance will be used to determine the grout weight. This weight will be recorded on the drilling log. The weight should be between 13.2 and 14 pounds per gallon. Grout will be thoroughly mixed and free of lumps before placement. After 24 hours, the abandoned site will be checked for grout settlement. Any settlement depression shall be filled with grout and rechecked 24 hours later. This process will be repeated until firm grout remains at ground surface without any depressions.

1.4 - Surveying

The surveying procedures described in this section are general guidelines for mapping the investigated SWMU. These guidelines may be modified if additional equipment, such as global positioning systems (GPS), is to be used. Field personnel will create a field map of the investigated SWMU through techniques described below.

1. Utilizing existing records or other known data, estimate the location and size of the SWMU.

2. Stake the estimated area and provide distance locations to known reference points (i.e., roads, buildings, etc.).

3. For providing a geophysical survey, stake the gridpoints as described in Section 1.1.2 of this FSP. Obtain concurrence of gridpoint location from CSSA and AFCEE.

4. After data reduction has been completed from the geophysical survey of the investigated SWMU, modify the map to reflect findings of the geophysical survey.

A map is currently available, or will be provided, for each investigated SWMU that specifically identifies the location of the SWMU.

1.5 - Equipment Decontamination

To prevent sample contamination from the onsite sampling equipment and machinery, decontamination will be conducted using the following procedures.

A decontamination pad, large enough to fully contain the equipment to be cleaned, will be set up. One or more layers of heavy plastic sheeting will be used to cover the ground surface. Sampling equipment that will come into direct contact with samples will not be allowed to come in contact with the plastic.

Drill rigs, drill pipe, and other equipment that does not come into contact with the sample medium will be decontaminated with a steam cleaner before initial use and after each borehole is completed. Drill bits will be decontaminated with a steam cleaner prior to use at each boring or monitoring well location. If the hot water cleaning alone is found to be ineffective, the equipment may be scrubbed with laboratory-grade detergent, then rinsed with high-pressure steam. All visible dirt, grime, grease, oil, loose paint, etc., will be scrubbed until it has been removed. When possible, drilling will proceed from the "least" to the "most" contaminated sites.

The casing, centralizers, and screen will either be certified clean by the manufacturers or will be decontaminated by steam cleaning.

Purge and development equipment such as pumps will be decontaminated by flushing or pumping laboratory-grade detergent solution, potable water, then ASTM Type II Reagent water (Reagent Grade II water) through the internal components (in the order listed below). The exterior of the pump inlet hose will be steam cleaned.

Sampling equipment includes augers, continuous-core samplers, hand trowels, bailers, pH meters, conductivity meters, shovels, knives, spatulas, and compositing bowls that directly contact samples. The following steps must be followed when decontaminating this equipment:

1. Set up a decontamination area at the site. The decontamination area should progress from "dirty" to "clean" and end with an area for drying decontaminated equipment. At a minimum, clean plastic sheeting must be used to cover the ground, tables, or other surfaces on which decontaminated equipment is to be placed. However, sampling equipment to be used for organic sample collection shall not come in contact with plastic after the final rinse; oil-free aluminum foil must be used. Plastic sheeting must also be placed to capture Reagent-Grade II water, hexane, and methanol used for rinsing equipment.

2. Wash the item thoroughly with a soapy, laboratory-grade detergent solution. Do not submerge pH meters or conductivity meters. Use a stiff-bristle brush to dislodge any clinging dirt. Disassemble any items that might trap contaminants internally before washing. Do not reassemble until decontamination is complete, and the items are dry.

3. Rinse the item in clear potable water. Rinse water should be replaced as needed, generally when cloudy.

4. Using an appropriate manual pump sprayer, rinse the item with ASTM Type II Reagent water.

5. Rinse equipment with pesticide grade methanol.

6. Rinse equipment with pesticide grade hexane.

7. After drying, wrap the cleaned item in oil-free aluminum foil for storage at least two feet above the ground.

8. Record the decontamination protocol, equipment, and description together with the date and time of decontamination in the appropriate logbook.

9. After decontamination activities are completed, collect disposable gloves, boots, and clothing. Place contaminated items in proper containers for disposal.

Decontamination fluid will be containerized pending analytical analysis of samples from the site. Decontamination fluids that are suspected to be hazardous will be disposed of in accordance with all applicable laws and regulations. Hexane and methanol cannot be disposed of by pouring on the ground. These chemicals will be captured and will be disposed as investigation-derived waste as explained in Section 1.7. Parsons ES will assist CSSA in planning the disposal of waste materials and fluids which cannot be treated at the wastewater treatment plant (WWTP).

Environmental samples scheduled for collection are believed to contain no or minimal waste or waste residues; therefore, the steps previously identified will provide for sufficient decontamination of the sampling equipment.

To ensure that the sampling equipment has been successfully decontaminated, an equipment blank will be collected at the rate of one per twenty samples. The equipment blanks will be analyzed for the same parameters as the other field samples collected during the field event.

1.6 - Field Activities

Parsons ES will complete the following tasks in anticipation of obtaining the necessary documentation for closure of the specified solid waste management units:

Two of the eight low priority sites do not require investigation, sites B-14 and the coal bins. The minimal field investigations for six of the eight low priority units (B-5, B-6, B-7, B-22, B-25, and B-26) will include mapping, geophysical surveys, and a minimum three surface soil samples. Geophysical surveys and a minimum of three soil borings will be completed at all thirteen medium priority sites. Samples will be taken from each soil boring, at the surface, middle, and total depths. If groundwater is encountered in a soil boring, the saturated/unsaturated interface of that boring will be sampled and analyzed for the contaminants discovered at the surface. If the interface is discovered to be contaminated, the boring will be completed as a groundwater monitoring well.

The additional high priority SWMUs will undergo noninvasive investigations to help identify closure potential.

The WP has a detailed description of all activities planned for the investigated SWMUs at CSSA.

1.7 - Investigation-Derived Waste Handling

Management of Investigation-Derived Wastes During Site Inspections (EPA, 1991) will be used as guidance for waste management methods during this project. This section describes the manner in which IDW will be handled at CSSA.

The onsite handling options provided by the EPA, when IDW are not Resource Conservation and Recovery Act (RCRA) hazardous as defined in 40 CFR 261.3, are listed below. These are only options and not necessarily the course of action that will be taken during the investigations at CSSA. Wastes anticipated as a result of investigation actions are drill cuttings, decontamination water, personal protective equipment (PPE), and decontamination equipment (DE).

For soil cuttings:

For groundwater:

For decontamination fluids:

For PPE and DE:

A solid waste is a RCRA characteristic hazardous waste if it exhibits the characteristics of ignitability, corrosivity, reactivity, or toxicity defined in 40 CFR 261 Subpart C. Toxicity is determined in accordance with the toxicity characteristic leaching procedure (TCLP).

If IDW consists of RCRA hazardous soils that pose no immediate threat to human health and the environment, the EPA recommends leaving the soils onsite within a delineated SWMU. Within the inner cantonment and outer cantonment pasture areas, soil cuttings will be containerized to eliminate contact of contaminated soils and visqueen sheeting with cattle. Otherwise, soil cuttings will remain on site wrapped in visqueen plastic until a determination can be made for its waste classification. CSSA will provide direction for disposing of RCRA hazardous IDW materials.

A small quantity of drums containing suspected hazardous waste may also be generated during drilling operations. Soil cuttings suspected to be hazardous based on site knowledge, field screening observations, odors and discoloration, and PID readings will be placed in clean 55-gallon U.S. Department of Transportation (DOT) approved drums. Each drum generated and stored at CSSA will have a self-adhesive label affixed to the outside of the container. At a minimum the label will document the following:

Water generated during development or purging will be poured out onto the ground if there are no signs of contamination. If any water is suspected to be contaminated, through field screening observations, the water will be sampled for characterization prior to disposal.

For IDW suspected to be contaminated (i.e., those wastes that have been placed into appropriate containers), hazardous characterization will be conducted in accordance with applicable EPA and TNRCC regulations. Initially, the analytical results for the sampling location will be used to characterize the contents of drums of solid or liquid waste. As needed, composite samples will be collected from drums of the same boring or SWMU location. Each composite sample will be from a maximum of ten drums. The composite samples will have TCLP analysis for RCRA hazardous waste constituents as provided by 40 CFR 261.

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