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Home My WebLink AboutNC0000396_App G Low Flow Sampling_20160219 Low Flow Sampling Plan Duke Energy Facilities Ash Basin Groundwater Assessment Program North Carolina June 10, 2015 Duke Energy | Low Flow Groundwater Sampling Plan Table of Contents TABLE OF CONTENTS Low Flow Sampling Plan ....................................................................................................... 1 1.0 PURPOSE ............................................................................................................................... 1 2.0 GENERAL CONSIDERATIONS ............................................................................................. 1 3.0 PROCEDURES ....................................................................................................................... 2 3.1 Pre-Job Preparation ............................................................................................................. 2 3.2 Water-Level Measurements ................................................................................................. 3 3.3 Well Purging ........................................................................................................................ 4 3.3.1 Low-Flow Well Purging ............................................................................................ 4 3.3.2 Volume-Averaging Well Purging .............................................................................. 8 3.4 Sampling ....................................................................................................................... 10 3.4.1 Low-Flow Sampling ............................................................................................... 10 3.4.2 Sampling after Volume-Averaging Purge ............................................................... 11 3.5 Sample Handling, Packing, and Shipping ..................................................................... 11 3.5.1 Handling ................................................................................................................ 11 3.5.2 Sample Labels ....................................................................................................... 11 3.5.3 Chain-of-Custody Record ...................................................................................... 12 3.6 Field Quality Control Samples ....................................................................................... 12 3.7 Field Logbook Documentation....................................................................................... 13 3.8 Decontamination and Waste Management ................................................................... 14 4.0 REFERENCES ..................................................................................................................... 14 APPENDIX ADecontamination of Equipment SOP ................................................................... 15 1.0 Purpose & Application ...................................................................................................... 16 2.0 Equipment & Materials .......................................................................................................... 16 3.0 Procedure ............................................................................................................................. 16 3.1 Decontamination of Non-Disposable Sampling Equipment .......................................... 16 3.2 Decontamination of Field Instrumentation .................................................................... 16 3.3 Decontamination of Groundwater Sampling Equipment ............................................... 17 3.4 Materials from Decontamination Activities .................................................................... 17 APPENDIX BSampling Equipment Check List – Table 1.......................................................... 18 APPENDIX CField Logbook/Data Sheets ................................................................................. 20 Duke Energy | Low Flow Groundwater Sampling Plar 1.0 PURPOSE 1 1.0 PURPOSE The purpose of this low flow sampling plan is to establish a standard operating procedure (SOP) to describe collection procedures for groundwater samples from monitoring wells using low-flow purging and sampling techniques or by the volume- averaged purging and sampling method at Duke Energy Ash Basin Groundwater Assessment Program facilities. 2.0 GENERAL CONSIDERATIONS Potential hazards associated with the planned tasks shall be thoroughly evaluated prior to conducting field activities. The Ready-To-Work Plan developed for each facility provides, among other items, a description of potential hazards and associated safety and control measures. Sampling personnel must wear powder-free nitrile gloves or equivalent while performing the procedures described in this SOP. Specifically, gloves must be worn while preparing sample bottles, preparing and decontaminating sampling equipment, collecting samples, and packing samples. At a minimum, gloves must be changed prior to the collection of each sample, or as necessary to prevent the possibility of cross-contamination with the sample, the sample bottles, or the sampling equipment. Field sampling equipment shall be decontaminated in accordance with the Decontamination of Equipment SOP (Appendix A) prior to use. Although sampling should typically be conducted from least to most impacted location, field logistics may necessitate other sample collection priorities. When sampling does not proceed from least to most impacted location, precautions must be taken to ensure that appropriate levels of decontamination are achieved. An example of equipment needed to properly conduct low-flow purging and sampling or volume- averaged groundwater purging and sampling is listed on the example checklist in Table 1 (Appendix B). If a portable generator is used to power the purge pump, it shall be attempted to be located downwind of the well being sampling to avoid cross-contamination of the sample with exhaust from the generator motor. Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 2 3.0 PROCEDURES The following sections describe the general operating procedures and methods associated with groundwater sampling. Any variation in these procedures must be approved by the Project Manager (PM) and Quality Assurance/Quality Control (QA/QC) Lead and must be fully documented. Field work cannot progress until deviations are approved or resolved. 3.1 Pre-Job Preparation The information listed below may be reviewed prior to sampling activities, if available, and can be beneficial on-site for reference in the field as necessary: • A list of the monitoring wells to be sampled; • Information describing well location, using site-specific or topographic maps or Global Positioning System (GPS) coordinates and descriptions tied directly to prominent field markers; • A list of the analytical requirements for each sampling location; • Boring logs and well construction details, if available; • Survey data that identify the documented point of reference (V-notch or other mark on well casing) for the collection of depth-to-groundwater and total well depth measurements; • Previous depth-to-groundwater measurements; • Previous pump placement depths (dedicated pumps as well as portable pumps) for each sampling location, if available; • Previous pump settings and pumping and drawdown rates, if available; and • Previous analytical results for each monitoring well, if known. The information above is useful when determining the sampling order, pump intake depth, and purge and recharge rates, and can facilitate troubleshooting. The following activities should be completed prior to mobilizing to the site: • Obtain equipment necessary for completing the sampling activities (see the example checklist in Table 1). • Ensure appropriate laboratory-provided bottles are available for both the required analyses and for QC samples and that there has been thorough coordination with the analytical laboratory. Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 3 • Obtain site-specific maps or GPS coordinates showing clearly marked monitoring well locations or groundwater sample points. • Review the project work control documents such as the Ready-To-Work Plan, and appropriate SOPs in an effort to determine project-specific sampling requirements, procedures, and goals. • Verify that legal right-of-entry has been obtained and site access has been granted, where required. • Instruct the field team to avoid discussing project data with the public and to refer questions to the Project Manager. 3.2 Water-Level Measurements Prior to pump placement, an initial depth-to-water level and total well depth should be measured. For monitoring wells screened across the water table, this measurement shall be used to determine the required depth to the pump intake (typically, approximately the mid-point of the saturated screen length for low-flow purging and sampling). The procedure for measuring water levels may include the following: 1) Inspect the well head area for evidence of damage or disturbance. Record notable observations in the field logbook. 2) Carefully open the protective outer cover of the monitoring well noting the presence of bee hives and/or spiders, as these animals are frequently found inside well covers. Remove any debris that has accumulated around the riser near the well plug. If water is present above the top of the riser and well plug, remove the water prior to opening the well plug. Do not open the well until the water above the well head has been removed. 3) If practical, well plugs shall be left open for approximately five minutes to allow the static water level to equilibrate before measuring the water level (if well plugs are vented, then a waiting period is not applicable). 4) Using an electronic water-level indicator accurate to 0.01 feet, determine the distance between the established point of reference (usually a V-notch or indelible mark on the well riser) and the surface of the standing water present in the well. Record these data in the field logbook. Repeat this measurement until two successive readings agree to within 0.01 feet. 5) Using an electronic water-level indicator accurate to 0.01 feet, determine the distance between the established point of reference (usually a V-notch or indelible mark on the well riser) and the bottom of the well. Note that there should not be considerable slack in the water-level indicator cable. Record these data in the field logbook. Repeat this measurement until two successive readings agree to within 0.01 feet. 6) If the monitoring well has the potential to contain non-aqueous phase liquids (NAPLs), probe the well for these materials using an optical interface probe. These wells will be attempted to be identified by the Project Manager prior to Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 4 mobilizing to the well. If NAPL is present, consult the Project Manager for direction on collecting samples for analysis. In general, do not collect groundwater samples from monitoring wells containing NAPL. 7) Decontaminate the water-level indicator (and interface probe, if applicable) and return the indicator to its clean protective casing. 3.3 Well Purging Wells must be purged prior to sampling to ensure that representative groundwater is obtained from the water-bearing unit. If the well has been previously sampled in accordance with this sampling plan, then the depth to the pump intake and the pumping rates should be duplicated to the extent possible during subsequent sampling events. Section 3.3.1 provides a description of low-flow well purging, and Section 3.3.2 provides a description of volume-averaging well purging (in the case it’s needed). 3.3.1 Low-Flow Well Purging Adjustable-rate peristaltic, bladder and electric submersible pumps are preferred for use during low-flow purging and sampling activities. Since purging and sampling are joined together as one continuous operation, care will be given to pump selection as it applies to the specific well conditions and analytes to be tested. Note that a ball valve (or similar valve constructed of polyethylene) may need to be installed to reduce the flow rate to the required level. The low-flow purging and sampling guidance is provided below: 1) Using the specific details of well construction and current water-level measurement, determine the pump intake set depth (typically the approximate mid-point of the saturated well screen or other target sample collection depth adjacent to specific high-yield zones). 2) Attach tubing and supporting rope (if applicable) to the pump and very slowly lower the unit until the pump intake depth is reached. Measure the length of supporting rope required, taking into account the pump length, to attain the required depth. Record the depth to the pump intake in the field logbook. Notes: 1) Sampling shall use new certified-clean disposable tubing. 2) Rope shall be clean, unused, dedicated nylon rope. If a pump is to remain in a well as part of a separate monitoring program, then the rope shall be suspended within the well above the water column for future use. If the pump is removed after sample collection, the rope shall be disposed. 3) After allowing time for the water level to equilibrate, slowly lower the electronic water-level probe into the well until the probe contacts the groundwater. Record the water level in the field logbook. Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 5 4) If the well has been previously sampled using low-flow purging and sampling methods, begin purging at the rate known to induce minimal drawdown. Frequently check the drawdown rate to verify that minimum drawdown is being maintained. If results from the previous sampling event are not known, begin purging the well at the minimum pumping rate of approximately 100 milliliters per minute (mL/min) (EPA, July 1996). Slowly increase the pumping rate to a level that does not cause the well to drawdown more than about 0.3 feet, if possible. Never increase the pumping rate to a level in excess of 500 mL/min (approximately 0.13 gallon per minute [gpm]). Record the stabilized flow rate, drawdown, and time on the field data sheets. 5) If the drawdown does not stabilize at 100 mL/min (0.026 gpm), continue pumping. However, in general, do not draw down the water level more than approximately 25% of the distance between the static water level and pump intake depth (American Society for Testing and Materials [ASTM], 2011). If the recharge rate of the well is lower than the minimum pumping rate but the drawdown is less than 25% of the distance between the static water level and pump intake depth after three volumes of well water are removed, then collect samples at this point even though indicator field parameters have not stabilized (EPA, July 1996). Commence sampling as soon as the water level has recovered sufficiently to collect the required sample volumes. Otherwise, the Volume-Averaging Well Purging method should be considered.Allow the pump to remain undisturbed in the well during this recovery period to minimize the turbidity of the water samples. Fully document the pump settings, pumping rate, drawdown, and field parameter readings on the Well Sampling / MicroPurge (Low Flow) Log in the field logbook. Note: For wells that either have very slow recharge rates, that draw down excessively (more than 25% of the distance between the static water level and pump intake depth) at the minimum pumping rate (100 mL/min or 0.026 gpm), or require a higher pumping rate (greater than 500 mL/min or 0.13 gpm) to maintain purging, the procedures described above may not apply. For these “special case” wells, the Field Team Leader shall seek guidance from the Project Manager about the appropriate purging and sampling methodologies to be employed (such as volume-averaged purging and sampling described in Section 3.3.2). 6) Once an acceptable flow rate has been established, begin monitoring designated indicator field parameters. Indicator parameters are pH, specific conductance, dissolved oxygen (DO), and turbidity. Although not considered purge stabilization parameters, temperature and oxidation reduction potential (ORP) will be recorded during purging. Base the frequency of the measurements on the time required to completely evacuate one volume of the flow through the cell to ensure that independent measurements are made. For example, a 500-mL cell in a system pumped at a rate of 100 mL/min is evacuated in five minutes; accordingly, measurements are made and recorded on the field data form (Appendix C) approximately five minutes apart. Indicator parameters have stabilized when three consecutive readings, taken at three to five-minute intervals, meet the following criteria (EPA, March 2013): Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 6 • pH ± 0.1 standard unit • Specific Conductance ± 5% in µS/cm • DO ± 0.2 mg/L or 10% saturation • Turbidity less than 10 NTUs The target for monitoring turbidity is readings less than ten nephelometric turbidity units (NTUs). In some instances, turbidity levels may exceed the desired turbidity level due to natural aquifer conditions (EPA, April 1996). When these conditions are encountered, the following guidelines shall be considered. • If turbidity readings are slightly above 10 NTU, but trending downward, purging and monitoring shall continue. • If turbidity readings are greater than 10 NTU and have stabilized to within 10% during three successive readings, attempt to contact the Project Manager prior to collecting the groundwater sample. • If turbidity readings are greater than 10 NTU and are not stable, well sampling shall be based upon stabilization of more critical indicator parameters (such as dissolved oxygen) without attainment of the targeted turbidity. Attempt to contact the Project Manger if this condition is encountered prior to collecting the groundwater sample. • If after 5 well volumes or two hours of purging (whichever is achieved first), critical indicator field parameters have not stabilized, discontinue purging and collect samples. Fully document efforts used to stabilize the parameters (such as modified pumping rates). Note: While every effort should be taken to ensure that indicator parameters stabilize, some indicator parameters are more critical with respect to certain contaminant types. It is important to identify which indicator parameters are most important to the project prior to commencement of field activities so that unnecessarily protracted purge times can be avoided. For example, the critical indicator parameter associated with metals is turbidity. While it is desirable to sample wells when turbidity measurements are less than 5 NTU, Duke Energy recognizes that these values may not be attainable. Duke Energy, and its sub- consultants, have taken multiple steps (e.g., use of pre-packed screens, carefully selected sand pack, etc.) to alleviate the potential for elevated turbidity in newly installed wells. However, even with these conservative and targeted well installation specifications, other naturally occurring conditions (e.g., iron fluctuation) may prevent sampling of wells at turbidity values less than 5 NTU. Following sample collection and laboratory data evaluation, Duke Energy may review these data with respect to turbidity values to determine if additional well development is needed or if well construction has affected groundwater conditions. It may be necessary to redevelop wells from time to time to minimize Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 7 sample turbidity. Fine silt and clay can collect at the base of a well over time. The effect on future sampling events can be reduced by lowering the tubing or pump to the bottom of the well (after all the groundwater samples have been collected) and pumping until the purge water from the bottom of the well screen is clear. Note: If purging of a well does not result in turbidity measurements of 10 NTU or less, the field sampler shall alert the Project Manager. The sampling team will assess options to reduce the turbidity as soon as possible. There are a variety of water-quality meters available that measure the water quality parameters identified above. A multi-parameter meter capable of measuring each of the water quality parameters referenced previously (except for turbidity) in one flow-through cell is required. Turbidity shall be measured using a separate turbidity meter or prior to flow into the flow through cell using an inline T-valve, if using one multi-meter during purging. The water quality meter (and turbidity meter) shall be calibrated as per manufacturer’s instructions. Calibration procedures shall be documented in the project field logbook including calibration solutions used, expiration date(s), lot numbers, and calibration results. Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 8 3.3.2 Volume-Averaging Well Purging For wells that either have very slow recharge rates, that draw down excessively at the minimum pumping rate (100 mL/min or 0.026 gpm), or require a higher pumping rate (greater than 500 mL/min or 0.13 gpm) to maintain purging (i.e., low-flow well purging and sampling is not appropriate), the volume-averaging well purging and sampling method may be used. The Field Team Leader shall seek approval from the Project Manager before utilizing the volume-averaging method instead of the low-flow method. 3.3.2.1 CALCULATE PURGE VOLUMES Based on the depth-to-water (DTW) and total depth (TD) measurements, the volume of standing water in the well must be calculated using the following procedures. 1) Subtract DTW from TD to calculate the length of the standing water column (Lwc) in the well. ܶܦ െ ܦܹܶ ൌ ܮ௪௖ 2) Multiply the length of the standing water column by the volume calculation (gallon per linear foot of depth) based on the inner casing diameter (see example list below) to determine the total standing water volume; this represents one well volume. ܸ௪ = ܮ௪௖ ൈ2ߨݎଶ 1-inch well = 0.041 gallon per linear foot 2-inch well = 0.163 gallon per linear foot 4-inch well = 0.653 gallon per linear foot 6-inch well = 1.469 gallons per linear foot 8-inch well = 2.611 gallons per linear foot 3) Multiply the well volume calculated in the previous step by three and five to obtain the approximate respective total purge volume (the target purge volume is between three and five standing well volumes). For wells with multiple casing diameters (such as open bedrock holes), calculate the volume for each segment. Take the sum of the values and multiply by three and five to determine the minimum and maximum purge volumes, respectively. 4) Fully document the volume calculation in the field logbook or on the Groundwater Sampling Field Sheets. Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 9 3.3.2.2 PURGE THE MONITORING WELL Determine the appropriate pump to be used for purging—the preferred and most commonly used methods involve the use of a surface centrifugal or peristaltic pump whenever the head difference between the sampling location and the water level is less than the limit of suction and the volume to be removed is reasonably small. Where the water level is below the limit of suction or there is a large volume of water to be purged, use the variable speed electric submersible pump as the pump of choice (EPA, 2013). In some cases (shallow wells with small purge volumes), purging with a bladder pump may be appropriate. Once the proper pump has been selected: 1) Set the pump immediately above the top of the well screen or approximately three to five feet below the top of the water table (EPA, 2013). 2) Lower the pump if the water level drops during purging. Note: Use new certified-clean disposable tubing for purging and sampling. Note: Although volume-averaged sampling involves purging a specified volume of water (such as three to five well volumes) rather than basing purge completion on the stabilization of water quality indicator parameters, measuring and recording water-quality indicator parameters during purging provides information that can be used for assessment and remedial decision-making purposes. Indicator parameters are pH, specific conductance, DO, and turbidity as described in Section 3.3.1. Temperature and ORP will also be recorded during purging. 3) During well purging, monitor the discharge rate using a graduated cylinder or other measuring device, water-quality indicator parameters (if desired), and DTW as follows: • Initially, within approximately three minutes of startup, • Approximately after each well volume is purged, and then • Before purge completion. 4) Record pump discharge rates (mL/ min or gpm) and pump settings in the field logbook. Also, record any changes in the pump settings and the time at which the changes were made. 5) Maintain low pumping rates to avoid overpumping or pumping the well to dryness, if possible. If necessary, adjust pumping rates, pump set depth, or extend pumping times to remove the desired volume of water. 6) Upon reaching the desired purge water volume, turn off the purge pump. Do not allow the water contained in the pump tubing to drain back into the well when the pump is turned off. Use an inline check valve or similar device, or if using a peristaltic pump, remove the tubing from the well prior to turning off the pump. It is Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 10 preferred to collect samples within two hours of purging, but acceptable for collection up to 24 hours of purging. Do not collect samples after 24 hours of purging. Note: The removal of three to five well volumes may not be practical in wells with slow recovery rates. If a well is pumped to near dryness at a rate less than 1.9 L/min (0.5 gpm), the well shall be allowed to completely recover prior to sampling. If necessary, the two-hour limit may be exceeded to allow for sufficient recovery, but samples should be collected within 24 hours of purge completion. 3.4 Sampling 3.4.1 Low-Flow Sampling Following are the procedures for the collection of low-flow groundwater samples. These procedures apply to sample collection for unfiltered and filtered samples using a 0.45 micron filter. See Appendix A for use of 0.1 micron filtered samples. 1) Record the final pump settings in the field logbook prior to sample collection. 2) Measure and record the indicator parameter readings prior to sample collection on both the stabilization form and in the field logbook. 3) Record comments pertinent to the appearance (color, floc, turbid) and obvious odors (such as sulfur odor or petroleum hydrocarbons odor) associated with the water. 4) Arrange and label necessary sample bottles and ensure that preservatives are added, as required. Include a unique sample number, time and date of sampling, the initials of the sampler, and the requested analysis on the label. Additionally, provide information pertinent to the preservation materials or chemicals used in the sample. 5) Collect samples directly from pump tubing prior to the flow-through cell or via the in-line T-valve used for turbidity measurements (as described Section 3.3.1 (6) above). Ensure that the sampling tubing remains filled during sampling and attempt to prevent water from descending back into the well. Minimize turbulence when filling sample containers, by allowing the liquid to run gently down the inside of the bottle. Fill the labeled sample bottles in the following order: • Metals and Radionuclides, • Filtered Metals and Radionuclides, if required, and then • Other water-quality parameters. 6) Seal each sample and place the sample on ice in a cooler to maintain sample temperature preservation requirements. Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 11 7) Note the sample identification and sample collection time in field logbook and on Chain-of-Custody form. 8) Once sampling is complete, retrieve the sample pump and associated sampling equipment and decontaminate in accordance with procedures outlined in the Decontamination of Equipment SOP (Appendix A). 9) Close and secure the well. Clean up and remove debris left from the sampling event. Be sure that investigation-derived wastes are properly containerized and labeled, if applicable. 10) Review sampling records for completeness. Add additional notes as necessary. 3.4.2 Sampling after Volume-Averaging Purge The procedures described below are for the collection of groundwater samples after a volume-averaged purge has been conducted. Volume- averaging purge methods are described in Section 3.3.2. 1) If sampling with a pump, care shall be taken to minimize purge water descending back into the well through the pump tubing. Minimize turbulence when filling sample containers by allowing the liquid to run gently down the inside of the bottle. Fill the labeled sample bottles in the following order: • Metals and Radionuclides, • Filtered Metals and Radionuclides, if required, and then • Other water-quality parameters. 2) If sampling with a bailer, slowly lower a clean, disposable bailer through the fluid surface. Retrieve the bailer and fill the sample bottles as described above. Care shall be taken to minimize disturbing the sample during collection. 3.5 Sample Handling, Packing, and Shipping Samples shall be marked, labeled, packaged, and shipped in accordance with the sections outline below. 3.5.1 Handling The samples will be stored in coolers for transport to the site. Collected samples will be placed on ice in the sampling coolers for pickup or transport to the laboratory for analysis. 3.5.2 Sample Labels All sample containers will be new, laboratory cleaned and certified bottles. The bottles will be properly labeled for identification and will include the following information: • Project Site/ID Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 12 • Sample identifier (Well ID) • Name or initials of sampler(s) • Date and time of collection • Analysis parameter(s)/method • Preservative 3.5.3 Chain-of-Custody Record Sample transport and handling will be strictly controlled to prevent sample contamination. Chain-of-Custody control for all samples will consist of the following: • Sample containers will be securely placed in coolers (iced) and will remain under the supervision of project personnel until transfer of the samples to the laboratory for analysis has occurred. • Upon delivery to the laboratory, the laboratory director or his designee will sign the Chain-of-Custody control forms and formally receive the samples. The laboratory will ensure that proper refrigeration of the samples is maintained. The Chain-of-Custody document contains information which may include: • Client name • Client project name • Client contact • Client address • Client phone/fax number • Sampler(s) name and signature • Signature of person involved in the chain of possession • Inclusive dates of possession • Sample identification • Sample number • Date & time of collection • Matrix • Type of container and preservative • Number of containers • Sample type - grab or composite • Analysis parameter(s)/ method • Internal temperature of shipping container upon opening in the laboratory 3.6 Field Quality Control Samples Field quality control involves the routine collection and analysis of QC blanks to verify that the sample collection and handling processes have not impaired the quality of the samples. Duke Energy | Low Flow Groundwater Sampling Plan 3.0 PROCEDURES 13 • Equipment Blank – The equipment blank is a sample of deionized water, which is taken to the field and used as rinse water for sampling equipment. The equipment blank is prepared like the actual samples and returned to the laboratory for identical analysis. An equipment blank is used to determine if certain field sampling or cleaning procedures result in cross-contamination of site samples or if atmospheric contamination has occurred. One equipment blank sample will be prepared per day or per 20 groundwater samples, whichever is more frequent. Field and laboratory QA/QC also involves the routine collection and analysis of duplicate field samples. These samples are collected at a minimum rate of approximately one per 20 groundwater samples per sample event. A field duplicate is a replicate sample prepared at the sampling locations from equal portions of all sample aliquots combined to make the sample. Both the field duplicate and the sample are collected at the same time, in the same container type, preserved in the same way, and analyzed by the same laboratory as a measure of sampling and analytical precision. 3.7 Field Logbook Documentation Field logbooks shall be maintained by the Field Team Leader to record daily activities. The field logbook may include the following information for each well: • Well identification number • Well depth • Static water level depth • Presence of immiscible layers (yes – no) • Estimated well yield, if known • Purge volume and purge pumping rate • Time well purge began and ended • Well evacuation procedure and equipment • Field analysis data • Climatic conditions including air temperature • Field observations on sampling event • Well location • Name of collector(s) • Date and time of sample collection • Sampling procedure • Sampling equipment • Types of sample containers used and sample identification numbers • Preservative used Duke Energy | Low Flow Groundwater Sampling Plan 4.0 REFERENCES 14 The Field Team Leader shall review the field logbook entries for completeness and accuracy. The Field Team Leader is responsible for completion of the required data collection forms. Example field logs are in Appendix C. 3.8 Decontamination and Waste Management Sampling equipment decontamination shall be performed in a manner consistent with the Decontamination of Equipment SOP (Appendix A). Decontamination procedures shall be documented in the field logbook. Investigation-derived wastes produced during sampling or decontamination shall be managed in accordance with State and Station-specific rules for disposal of wastes. 4.0 REFERENCES American Society for Testing and Materials (ASTM). Standard Practice for Low-Flow Purging and Sampling for Wells and Devices Used for Ground-Water Quality Investigations, D 6771-02. 2011. Test Methods for Evaluating Solid Waste - Physical/Chemical Methods (SW-846), Third Edition. U.S. Environmental Protection Agency. Update I, II, IIA, IIB, III, IIIA, IVA and IVB. United States Environmental Protection Agency (EPA), Office of Research and Development, Office of Solid Waste and Emergency Response. Ground Water Issue, “Low-Flow (Minimal Drawdown Sampling Procedures). Document Number EPA/540/S- 95/504,” April 1996. U.S. EPA. Region 4, Groundwater Sampling Operating Procedure. Document Number SESDPROC-301-R3, November 2013. U.S. EPA. Region I, Low Stress (Low Flow) Purging and Sampling Procedure for the Collection of Ground Water Samples from Monitoring Wells, Revision 2, July 1996. Duke Energy | Low Flow Groundwater Sampling Plar Decontamination of Equipment SOP 15 A Decontamination of Equipment SOP Duke Energy | Low Flow Groundwater Sampling Plar Purpose & Application 16 1.0 Purpose & Application This procedure describes techniques meant to produce acceptable decontamination of equipment used in field investigation and sampling activities. Variations from this SOP should be approved by the Project Manager prior to implementation and a description of the variance documented in the field logbook. 2.0 Equipment & Materials • Decontamination water, • Alconox detergent or equivalent non-phosphate detergent • Test tube brush or equivalent • 5-gallon bucket(s) • Aluminum foil • Pump 3.0 Procedure 3.1 Decontamination of Non-Disposable Sampling Equipment Decontamination of non-disposable sampling equipment used to collect samples for chemical analyses will be conducted prior to each sampling as described below. Larger items may be decontaminated at the decontamination pad. Smaller items may be decontaminated over 5-gallon buckets. Wastewater will be disposed in accordance with applicable State and Station-specific requirements. 1. Alconox detergent or equivalent and water will be used to scrub the equipment. 2. Equipment will be first rinsed with water and then rinsed with distilled/deionized water. 3. Equipment will be air dried on plastic sheeting. 4. After drying, exposed ends of equipment will be wrapped or covered with aluminum foil for transport and handling. 3.2 Decontamination of Field Instrumentation Field instrumentation (such as interface probes, water quality meters, etc.) will be decontaminated between sample locations by rinsing with deionized or distilled water. If visible contamination still exists on the equipment after the rinse, an Alconox (or equivalent) detergent scrub will be added and the probe thoroughly rinsed again. Decontamination of probes and meters will take place in a 5-gallon bucket. The decontamination water will be handled and disposed in accordance with applicable State and Station-specific requirements. Duke Energy | Low Flow Groundwater Sampling Plar 3.0 Procedure 17 3.3 Decontamination of Groundwater Sampling Equipment Non-disposable groundwater sampling equipment, including the pump, support cable and electrical wires in contact with the sample will be thoroughly decontaminated as described below: 1. As a pre-rinse, the pump will be operated in a deep basin containing 8 to 10 gallons of water. Other equipment will be flushed with water. 2. The pump will be washed by operating it in a deep basin containing phosphate- free detergent solution, such as Alconox, and other equipment will be flushed with a fresh detergent solution. Detergent will be used sparingly, as needed. 3. Afterwards, the pump will be rinsed by operating it in a deep basin of water and other equipment will be flushed with water. 4. The pump will then be disassembled and washed in a deep basin containing non-phosphate detergent solution. All pump parts will be scrubbed with a test tube brush or equivalent. 5. Pump parts will be first rinsed with water and then rinsed with distilled/deionized water. 6. For a bladder pump, the disposable bladder will be replaced with a new one for each well and the pump reassembled. 7. The decontamination water will be disposed of properly. 3.4 Materials from Decontamination Activities All wastewater and PPE generated from decontamination activities will be handled and disposed in accordance with applicable State and Station-specific requirements. Duke Energy | Low Flow Groundwater Sampling Plar Sampling Equipment Check List – Table 1 18 B Sampling Equipment Check List – Table 1 Duke Energy | Low Flow Groundwater Sampling Plar Sampling Equipment Check List – Table 1 19 Table 1: Suggested Groundwater Sampling Equipment & Material Checklist Item Description Check Health & Safety Nitrile gloves Hard hat Steel-toed boots Hearing protection Field first-aid kit Fire Extinguisher Eyewash Safety glasses Respirator and cartridges (if necessary) Saranex™/Tyvek® suits and booties (if necessary) Paperwork Health and Safety Plan Project work control documents Well construction data, location map, field data from previous sampling events Chain-of-custody forms and custody seals Field logbook Measuring Equipment Flow measurement supplies (for example, graduated cylinder and stop watch) Electronic water-level indicator capable of detecting non-aqueous phase liquid Sampling Equipment GPS device Monitoring well keys Tools for well access (for example, socket set, wrench, screw driver, T-wrench) Laboratory-supplied certified-clean bottles, preserved by laboratory (if necessary) Appropriate trip blanks and high-quality blank water Sample filtration device and filters Submersible pump, peristaltic pump, or other appropriate pump Appropriate sample and air line tubing (Silastic®, Teflon®, Tygon®, or equivalent) Stainless steel clamps to attach sample lines to pump Pump controller and power supply Oil-less air compressor, air line leads, and end fittings (if using bladder pump) In-line groundwater parameter monitoring device (for example, YSI-556 Multi- Parameter or Horiba U-52 water quality meter) Turbidity meter Bailer Calibration standards for monitoring devices Duke Energy | Low Flow Groundwater Sampling Plar Field Logbook/Data Sheets 20 C Field Logbook/Data Sheets Duke Energy | Low Flow Groundwater Sampling Plar Field Logbook/Data Sheets 21 Groundwater Potentiometric Level Measurement Log Well Number Time Depth to Water (ft)* Depth to Bottom (ft)* Water Column Thickness (ft) Reference Point Elevation (ft, MSL) Potentiometric Elevation (ft, MSL) Remarks Field Personnel: Checked By: * - Measurements are referenced from the top of the PVC inner casing (TOC) for each respective monitoring well. TOCs shall be surveyed by a Professional Land Surveyor and referenced to NAVD88. Duke Energy | Low Flow Groundwater Sampling Plar Field Logbook/Data Sheets 22 Well Sampling / MicroPurge Log Project Name: Sheet: of Well Number: Date: Well Diameter: Top of Casing Elevation (ft, MSL): Pump Intake Depth (ft): Total Well Depth (ft): Recharge Rate (sec): Initial Depth to Water (ft): Discharge Rate (sec): Water Column Thickness (ft): Controller Settings: Water Column Elevation (ft, MSL): Purging Time Initiated: 1 Well Volume (gal): Purging Time Completed: 3 Well Volumes (gal): Total Gallons Purged: WELL PURGING RECORD Time Volume Purged (gallons) Flow Rate (mL/min) Depth to Water (ft) Temperature (°C) pH (s.u.) Specific Conductance (mS/cm) Dissolved Oxygen (mg/L) ORP (mV) Turbidity (NTU) Comments Stabilization Criteria Min. 1 Well Volume + 3°C + 0.1 + 3% + 10% + 10 mV < 5 NTU or + 10 % if > 5 NTU GROUNDWATER SAMPLING RECORD Sample Number Collection Time Parameter Container Preservative Duke Energy | Low Flow Groundwater Sampling Plar Field Logbook/Data Sheets 23 DAILY FIELD REPORT Project Name: Field Manager: Field Personnel: Date: Weather: Labor Hours Equipment Materials Field Observations: Submitted by: Reviewedby: