Instructors/Trainers. Groundwater Sampling Training Workshop. Objectives of GW Sampling. Agenda Estimated time (minutes) Course Objectives

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1 Instructors/Trainers Groundwater Sampling Training Workshop Florida Society of Environmental Analysts Spring Meeting Sirata Beach Resort May 21, 2008 Delia Ivanoff, South FL Water Management District Tom Frick, Biological Research Associates Juan Manzano, City of Delray Beach Cathie McGwier, Lake County Rick Caughey, Benchmark EnviroAnalytical Linda Hoffman, HSW Engineering David Kirschner, US Sugar Corporation Topic Agenda Estimated time (minutes) Course Objectives Introduction and Scope Ground Water Monitoring: Objectives, strategies, and constraints General DEP Sampling Requirements Decontamination Documentation Field QC Requirements Water Level, Column Determination and Water Volume Well Purging-Equipment Volume, Frequency and Dry Purge Sampling Equipment and Procedures Low-Flow Sampling Field Test Meter Calibration Concurrent Hands-on Demo (1 hour): Hands-on Demo Field Test Meters Hands-on Demo Peristaltic pump, submersible pump Understand the science and objectives behind groundwater sampling Discuss DEP and project requirements. Give you an opportunity to expand on what you already know and ask questions. Provide hands-on training to improve technique. Hands-on Demo Low flow Objectives of GW Sampling Collect samples that are representative of in situ groundwater conditions in the formation of interest at the site under investigation. Regulatory compliance monitoring Non-regulatory compliance monitoring What is a representative GW sample? Reflects the physical and chemical composition of naturally occurring GW in that site formation Ex. From a water supply well, a representative sample = volume averaged concentration Ex. Contamination plume tracking = must be representative of depth 1

2 Factors affecting GW Representativeness GW flow paths and flow through wells Hydraulics within wells between sampling events Placement of sampling points and intake Installation method Suitability of sampling point design (material construction, diameter, depth, screen length, and screen slot size) Method, timing, and duration of sampling point development Long-term maintenance of sampling point Geochemical factors: pressure and temperature changes in the sample, entrainment of particulates, agitation or aeration during sampling Effect of Sample Support on GW Data Actual project & data using DP- MIP (direct-push membrane- interface probe (w/ ECD detector) Graphic adapted from Columbia Technologies Regulatory Monitoring Resource Conservation and Recovery Act Comprehensive Environmental Response, Compensation, and Liability Act, a.k.a. Superfund Clean Water Act Toxic Substances Control Act Safe Drinking Water Act Non-regulatory Monitoring Ambient GW monitoring program Monitoring for salt intrusion (over pumping) Research studies such as leaching studies What does the DEP QA Rule (FAC ) require? GENERAL DEP SOP REQUIREMENTS Use DEP SOPs (revision date 2/1/04) Pre-approve alternative procedures Keep mandatory documentation Follow preservation & holding times Auditing 2

3 General Considerations for Sampling Understanding of sampling and Data Quality Objectives Obtaining a representative sample Maintaining the integrity of the sample Documentation General Sampling Procedures (FS 1000) Important information for all types of sampling Useful tables: Sample Preservation, Holding Times & Container Types Construction Materials & Approved Sampling Equipment General Aqueous Sampling (FS 2000) Collection, Filtration and Preservation Procedures Instructions for Specific Analyte Groups FS 2000 & FS 2001 Filtering & Performed on-site Before chemical preservation Preservation Use tables FS through FS FS FS 2009 Instructions for specific analyte groups: Collecting VOC Samples Sampling for Hydrocarbons (Oil &Grease, TRPH, FL-PRO) Sampling for Bacteria Sampling for Cyanide 3

4 Decontamination (FC 1000) Performance-Based Cleaning Cleaning to meet a set of specifications rather than following a rigid, required procedure Propose and demonstrate effective technique Documentation (FD 1000) There are universal requirements as well as specifics for each type of documentation. Example forms: Groundwater Sampling Checklist (FD ) and Groundwater Sampling Log (FD ) Field test logs (FD9000-7, 8, &9) Documenting Sample Information Link bottles to records. Unique bottle ID Also, Site Date Time Numbered if multiples 4

5 FIELD QC REQUIREMENTS Field Quality Control (FQ 1000) Required Sampling QC Blanks Optional Duplicates or Replicates Split Samples Your DEP SOP tells you which analytes require QC blanks to be taken. What are blanks for? Monitor sampling environment, container/equipment cleaning, preservatives, analyte-free water, and storage and transport conditions. Why use blanks? Show that samples have not been contaminated Ensure that samples are representative of the sampling source Field-collected data have stated limits of precision and accuracy Handle blanks exactly like the associated environmental samples! Field Blanks Analyte-free water collected directly into a sample bottle at the sampling site. Equipment Blanks Analyte-free water collected by rinsing the sampling equipment at the sampling site. Pre-cleaned equipment blank Collect before using equipment Field-cleaned equipment blank Collect after cleaning equipment in the field, in between sampling sites Trip Blanks (VOCs Only) VOC vials filled with analyte-free water accompany the real VOC samples through the entire sampling trip. Remain unopeneduntil analysis Min. 1 vial per VOC cooler, and trip. For each Project and each matrix and analyte combination (except VOCs), Collect 1 blank for 20 environmental samples 5

6 Summary of Changes Related to GW Sampling Clarify procedures for field-qc Blanks New groundwater procedures for large-volume, high-recharge wells. Allow collection of extractable (semivolitile) organic analytes through peristaltic pump. Update sample preservation/holdingtime tables. Groundwater Sampling (FS2200) FS 2200 Groundwater Sampling Contents Equipment Selection Measuring Water Level in Monitoring Wells Calculating Required Purge Volume Placement of Purging Devices in the Well Stabilization Parameter Measurement Purging Completion Criteria Purging & Sampling Techniques for Monitoring Wells Purging & Sampling Wells with Installed Plumbing Purging & Sampling Remediation Installations Use the following FDEP SOPs in conjunction with FS 2200: FA 1000 Regulatory Scope and Administrative Procedures for Use of DEP SOPs FC 1000 Cleaning/Decontamination Procedures FD 1000 Documentation Procedures FQ 1000 Field Quality Control Requirements FS 1000 General Sampling Procedures FS 2000 General Aqueous Sampling FT 1000 Field Testing and Measurement FS 2200 Groundwater Sampling FS 2440 Groundwater Purging & Sampling Groundwater Specifications to ensure: Representative sample Collect fresh formation (aquifer) water No Contamination Proper placement of purging devices Appropriate equipment Bailers are not recommended Proper purging completion Important considerations for: Low-Recharge Wells Can t achieve purging completion criteria Time between purging and sampling Wells with installed plumbing 6

7 Typical Well Configurations Wells without Plumbing: equipment are brought to the well to purge and sample unless dedicated equipment is placed in the well. Wells with In-Place Plumbing: Plumbing is routinely used for purposes other than purging and sampling, such as for water supply. They are generally found at wellfields, industrial facilities, and private residences. (see FS 2300). Air Strippers or Remedial Systems: These types of systems are installed as remediation devices. Sample these wells like drinking water wells (see FS 2300). Groundwater (FS2440) Important considerations for: Low-Recharge Wells Can t achieve purging completion criteria Time between purging and sampling Wells with installed plumbing Water Level Measurement» Water Level Measurements: Use an electronic probe or chalked tape to determine the water level. Decontaminate all equipment before use.» Measure the depth to groundwater from the top of well casing to the nearest 0.01 foot and always measure from the same reference point or survey mark on the well casing. If there is no reference mark, measure from the north side of the casing. Record the measurement and the reference point. Electronic Probe Follow the manufacturer s instructions for use. Record the measurement.» Chalked Line Method: This method is not recommended if collecting samples for organic or inorganic parameters. Lower chalked tape into the well until the lower end is in the water (usually determined by the sound of the weight hitting the water). Record the length of the tape relative to the reference point (see section 3.2 above). Quickly remove the tape from the well. Record the length of the wetted portion to the nearest 0.01 foot.» Determine the depth to water by subtracting the length of the wetted portion (see section above) from the total length (see section above). Record the result. Water Column Determination Do not determine the total depth of the well by lowering the probe to the bottom of the well before purging and sampling. If the well must be sounded, delay purging and sampling activities for at least 24 hours after the well was sounded or for a time sufficient to meet the purge stabilization criterion for turbidity. Alternatively, collect samples before sounding the well. Subtract the depth to the top of the water column from the total well depth to determine the length of the water column. The total well depth depends on the well construction. Some wells may be drilled in areas of sinkhole or karst formations or rock leaving an open borehole. Attempt to find the total borehole depth in cases where there is an open borehole below the cased portion. Well Volume Calculations V = (0.041)d x d x h Where: V = volume in gallons d = well diameter in inches h = height of the water column in feet Alternate way of determining well volume V = [Gallons per Foot of Water] x h Where: V = volume in gallons h = height of the water column in feet Casing Internal Diameter Approximate Gallons per Foot of Water

8 Determining Purging Equipment Volume Calculate the total volume of the pump, associated tubing, and container that is used for in situ measurements (flow container), if used, using the following equation: V = p + ((0.041)d x d x l) + fc Where: V = volume in gallons p = volume of pump in gallons d = tubing diameter in inches l = length of tubing in feet fc = volume of flow cell in gallons Initial Inspection Verify the identification of the monitoring well by examining markings, sign plates, placards or other designations. Remove the well cover and remove all standing water around the top of the well casing (manhole) before opening the well cap. Inspect the exterior protective casing of the monitoring well for damage and document the results of the inspection if there is a problem. It is recommended that you place a protective covering around the well head. Replace the covering if it becomes soiled or ripped. Inspect the well lock and determine whether the cap fits tightly. Replace the cap if necessary. Well Purging Well Purging Selecting appropriate purging equipment Pumps are generally used. Bailers may be used if approved by an FDEP program, or if bailer use is specified in a permit, contract or FDEP order (see Table FS ). Equipment Volume Frequency Dry Purge Types of Pumps Used for Purging and Sampling Non-dedicated (Portable) Pumps Variable Speed Peristaltic Pump Variable Speed Centrifugal Pump Variable Speed Electric Submersible Pump Variable Speed Bladder Pump Dedicated Portable Pumps Variable Speed Electric Submersible Pump Variable Speed Bladder Pump Measuring Purge Volume Measure and record purge volume Method 1: Use a graduated container and multiply the number of times the container was emptied by the volume of the container. Method 2: Estimate the volume based on pumping rate. amount of water that is discharged per minute (D) = Measured amount Total time in minutes time needed to purge one (1) well volume or one (1) purging equipment volume = volume D 8

9 Stabilization Measurement Frequency Pump the minimum volume as prescribed below, then begin stabilization measurements. Wells with Fully Submerged Screen and Pump or Intake Tubing Placed at the Top of the Water Column (conventional purge): Purge a minimum of one well volume prior to collecting measurements of the field parameters. Allow at least one quarter well volume to purge between subsequent measurements. Use this option if well screened interval is unknown. Wells with Fully Submerged Screen and Pump or Intake Tubing Placed Within the Screened Interval (minimizing purge volume): Purge until the water level has stabilized (well recovery rate equals the purge rate), then purge a minimum of one volume of the pump, associated tubing and flow container (if used) prior to collecting measurements of the field parameters. Take measurements of the field parameters no sooner than two to three minutes apart. Purge at least three pump volumes, associated tubing and flow container, if used, prior to collecting a sample. Wells with a Partially Submerged Well Screen: Purge a minimum of one well volume prior to collecting measurements of the field parameters. Take measurements of the field parameters no sooner than two to three minutes apart. Purging Completion Best way is to use a flow through device with the field meter Every attempt must be made to match the pumping rate with the recharge rate of the well before evaluating the purging criteria. Every attempt must be made to match the pumping rate with the recharge rate of the well before evaluating the purging criteria. Purging Criteria 1 Purging Criteria 2 (If criteria for DO or Turbidity cannot be met) Three (3) consecutive measurements of the five (5) parameters must be within the stated limits. Use the last three consecutive measurements taken to evaluate. The range between the highest and the lowest values for the last three measurements of temperature, ph, and specific conductance must be less than the limits. The last three consecutive measurements of dissolved oxygen and turbidity must all be at or below the limits. Temperature ph Specific Conductance Dissolved Oxygen Turbidity C Std Units + 5.0% of reading <20% Saturation <20 NTU Three (3) consecutive measurements of the five (5) parameters listed below must be within the stated limits. Use the last three consecutive measurements taken before purging is stopped to evaluate. The range between the highest and the lowest values for the last three measurements cannot exceed the limits. Temperature ph Specific Conductance Dissolved Oxygen Turbidity C Std Units + 5.0% of reading mg/l or 10%, whichever is greater + 5 NTUs or 10%, whichever is greater If Criteria 1 and 2 cannot be met Troubleshoot: Check the instrument condition and calibration, purging flow rate and all tubing connections All measurements that were made during the attempt must be documented. Decide whether or not to collect a sample or to continue purging after five (5) well volumes or five (5) volumes of the screened interval. One fully dry purge not recommended applies only if other purging was attempted and if it is not possible to balance the pumping rate with the rate of recharge at very low pumping rates (< 100 ml/minute). 9

10 FS 2212 & FS 2213 Conventional Purge FS 2212 & FS 2213 Minimized Purge Volumes To Pump Intake placed at the top of water column. Calculate well volume. Purge one well volume. To Pump Well screen length 10 feet. Configuration is used for both purging and sampling. Place intake or pump at mid-screen. Calculate equipment volume. Water Level Screened Interval Intake Measure stabilization parameters no sooner than each ¼ well volume interval. Purge at least 1½ well volumes. Water Level Screened 10 ft Interval Intake Purge one equipment volume. Measure stabilization parameters. Collect additional measurements no sooner than every 2 minutes. Purge a minimum of 3 equipment volumes. Partially Submerged Screen Screened Interval FS 2212 & FS 2213 To Pump Water Level Intake placed at ½ distance between top of water column and bottom of screen. Calculate well volume. Purge one well volume. Measure stabilization parameters. Collect additional measurements no sooner than every 2 minutes. Purging Monitoring Wells (no permanent plumbing) Determine depth of tubing or pump placement Position the intake hose or pump at the midpoint of the screened or open hole interval if the following criteria can be met: The same pump must be used for both purging and sampling, The well screen interval must be less than or equal to 10 feet, and The well screen must be fully submerged. Intake General Purging Procedures Avoid dropping anything to bottom of well to minimize turbidity Measure water level frequently during purging Ensure proper pump or tubing placement in well Record placement depth pump or tubing Purging with a Pump Place Intake at Correct Depth Stabilize Drawdown with Pump Rate Purge Required Minimum Volumes Measure Parameters at Proper Frequency Satisfy Purge Completion Criteria 10

11 Purging Wells with In Place Plumbing Continuously Running Pumps Select the spigot that is closest to the pump and before any storage tanks (if possible). Remove all hoses, aerators and filters (if possible). Open the spigot and purge at maximum flow. If a storage tank is located between the pump and the spigot, purge the volume of the tank, lines and spigot. If the spigot is before any storage tank, purge until sufficient volume is removed to flush the stagnant water from the spigot and the tap line to the spigot. Reduce the flow rate to < 500 ml/minute (a 1/8 stream) or approx. 0.1 gpm before collecting samples. When sampling for VOCs, reduce the flow to <100 ml/minute before collecting the samples. SAMPLE COLLECTION Intermittently Running Pumps Open the spigot and purge sufficient volume to flush the spigot and lines and until the purging completion criteria are met. flow rate of <500 ml/minute (a 1/8 stream) or approx. 0.1 gpm before collecting samples. When sampling for VOCs, reduce the flow to < 100 ml/minute before collecting the samples. GW Sample Collection Collect samples immediately after purging is complete. The time period between completing the purge and sampling cannot exceed six hours. If sample collection does not occur within one hour of purging completion, re-measure the five field parameters just prior to collecting the sample. Measured values must be within 10% of the previous measurements; otherwise re-purge the well. Collecting Samples With Bailers Lower and Raise at 2 cm/sec Minimize Agitation of Water Column Avoid Scraping Well Casing Minimize Aeration & Agitation during Pouring of VOC Samples Wells with Installed Plumbing Purge and sample from tap between well head and pressure tank or at point closest to pump Remove hoses, aerators and filters between sample tap point and pump, if possible Purge pressure tank, lines and spigot until stabilization is achieved per FS 2212, section 3 For continuously pumping systems, flush stagnant volume of system only Reduce flow to < 500 ml/min (< 100 ml/min for VOC) Collect samples directly into sample containers FS 2221 Collecting Organic Samples With Peristaltic Pumps The trap method for extractable organics The straw technique for VOCs Groundwater Sampling 11

12 Low Flow Purging and Sampling Aka Micro-, low-stress, low-impact, minimal drawdown purging/sampling Required equipment Required knowledge of well construction details Pump intake Pumping rate Water level monitoring Stabilization indicator parameter monitoring Low-flow Purging and Sampling vs. Traditional Methods Improved sample quality Reduced need for sample filtration Improved data accuracy and precision Sample represents a smaller volume of the formation better accuracy in detecting contamination distributions and loading Increased well life through reduced pumping stress Significant reduction in purge volume and savings related to cost for disposal Efficiency improvement shorter purging and sampling time per site Field Test Meter Calibration Requirements Field Testing (FT 1000 FT 3000) Used for checking stabilization postpurging Also for monitoring groundwater in-situ condition Important Considerations: Calibration of instruments Verification of instruments Documentation Chronological: Quantitative: Bracketing Calibration & verification verification Samples Time 1 24 hours Time Standard Sample Standard (10) (100) Table FT : Field Testing Acceptance Criteria Parameter Acceptance Criteria ph Standard ph Units of buffer or more stringent (FT 1100) program criteria Specific Conductance +5% of standard value (FT 1200) Temperature o C of NIST-traceable value (with correction factors) (FT 1400) Verification over range of applicable values Dissolved Oxygen +0.3 mg/l of theoretical value (see Table FT ) (FT 1500) Turbidity NTU: + 10% of standard value (FT 1600) NTU: + 8% of standard value NTU: + 6.5% of standard value > 100 NTU: + 5% of standard value Total Residual Chlorine calibration curve correlation coefficient (FT 2000) +10% of primary standard value + 10% of secondary standard value Color comparator acceptance criterion: + 10% of primary standard value 12

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