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HomeMy WebLinkAboutMO-30159_49214_CA_SCH_20230414_Site Check 100 East Ruffin Street ꞏMebane, North Carolina 27302 Telephone (919) 563-9091 ꞏFacsimile (919) 563-9095 www.terraquestpc.com April 14, 2023 Allyson Sonntag First Citizens Bank & Trust Company 4300 Six Forks Rd. Raleigh, NC 27609 Re: Summary of Phase II Soil Sampling Assessment Letter BCA Property Mgmt., LLC 280 Ervin Woods Dr. Kannapolis, Rowan County, NC First Citizens RIMS File#: 23-000364-02-1 Terraquest Project No. 03323 Dear Mrs. Sonntag: Terraquest Environmental Consultants, P.C. (Terraquest) completed soil sampling activities at the BCA Property Mgmt., LLC property located at 280 Ervin Woods Dr. in Kannapolis in Rowan County, NC (herein referred to as the subject property). The purpose of this letter is to summarize the findings of the limited soil assessment performed at the subject property by Terraquest and explains the ramifications of what was discovered. The location of the subject property is depicted in the attached Figure 1. Site Summary The subject property totals 4 acres in size and contains a landscaping business office building, maintenance garage building, and maintenance yard built in 1988. The subject property is located outside the city limits of Kannapolis, NC. Historically the subject property has been woods and a residence. Surrounding properties have historically been cultivated farmland and woods with a gradual development of residences and light industrial buildings to the east and west and a sand rock pit to the south. A water supply well is connected to the subject property’s buildings. Each of the buildings has their own septic system that are located on the adjacent properties to the east and west. Initial Site Survey The following items were identified on the subject property during the completion of the Phase I ESA Report dated December 1, 2022 by Mid-Atlantic Associates, Inc. of Raleigh, NC: 1) The four petroleum aboveground storage tanks present a material threat of a future release. BCA Property Mgmt., LLC 280 Ervin Woods Dr., Kannapolis, Rowan County, NC Page 2 April 14, 2023 2) The presence of a vehicle repair pit with observed floor staining and a floor drain that likely drains to the subsurface septic field. 3) A potential heating oil UST associated with a former residence located in the western portion of the property. On March 30, 2023, Terraquest completed a site visit and identified the following items: 1) An approximate 280-gallon heating oil UST is located off the west side of the maintenance garage building. The UST supplies the furnace located in the garage building but is currently not in use. 2) A 1,000-gallon or greater waste oil UST is located off the south side of the office building. The waste oil UST is connected to the oil changing pit floor drain and drain funnel through underground pipes. The lawn mowing maintenance crew periodically places waste oil generated from lawn maintenance equipment in the UST. Historically, it was used during the servicing of the trucks of the former trucking business located on the subject property. 3) The septic system for the office building is located on the adjacent property to the east owned by JAM Logistics LLC. 4) The septic system for the maintenance garage building is located on the adjacent property to the west owned by Eric Wilson et al. 5) Two concrete holding tanks greater than 5,000-gallons each are located south of the wash pad in the southwest corner of the property. The tanks are holding tanks that are periodically pumped out when full. The tanks are currently not being used and were mostly empty during the site visit. Terraquest confirmed the locations, approximate sizes, and current/former uses of the above items with the former property owner David Ervin. The locations of the above items are depicted in the attached Figure 2. Phase II ESA The focus of the Phase II ESA performed by Terraquest was to determine the potential presence of USTs in the vicinity of the former residence and the soil quality in the vicinity of the 280-gallon heating oil UST and the 1,000-gallon or greater waste oil UST. Given the inactive status and non- hazardous use of the wash pad, the concrete holding tanks were not investigated during the Phase II ESA. Geophysical Investigation On March 30, 2023, Terraquest contracted the completion of geophysical investigation of the subject property. The survey was conducted by East Coast Geophysics, Inc. of Apex, NC. The geophysical investigation, consisting of metal detection and GPR surveys, was completed to determine the presence of the current and potential UST basins and product lines and private buried utilities on the subject property. BCA Property Mgmt., LLC 280 Ervin Woods Dr., Kannapolis, Rowan County, NC Page 3 April 14, 2023 The following conclusions can be made from the GPR study: 1) The heating oil UST off the west side of the garage building is approximately 280-gallons in capacity. 2) The waste oil UST off the south side of the office building is approximately 1,000 or more gallons. The dimensions were difficult to determine given its proximity to the metal siding of the office building. 3) No USTs were noted on the property in the vicinity of the former residence. During the Phase II ESA site visit on March 30, 2023, Terraquest personnel advanced soil borings in the vicinity of the heating oil and waste oil USTs. Soil Sampling To determine soil quality at the subject property, Terraquest advanced the following soil borings:  SB1 and SB2 – at the 280-gallon heating oil UST along the west side of the garage building  SB3, SB4, and SB5 – at the 1,000-gallon or greater waste oil UST south of the office building The soil borings were advanced using direct push technology and a Macro-Core tube retrieval sampling system. Direct push technology consists of advancing a sampling device into the subsurface soils by applying static pressure, by applying impacts, by applying vibration, or any combination thereof, to the above ground portion of the sampler extensions until the sampler has advanced to the desired depth (ASTM D6282). A single tube Macro-Core sample system was utilized to collect soil samples in five-foot intervals. A single tube sample system used a hollow extension/drive rod to advance and retrieve the sampler. Within the hollow extension, a new, single-use, poly-vinyl chloride (PVC) liner retained the soil sample as the tube is driven into the ground. The specific direct push equipment utilized was a Geoprobe 7822DT. The Macro-Core tube was decontaminated between each 5-foot sample interval in a soil boring using a Liquinox and tap-water mixture. A new PVC liner was used to collect soil from each 5-foot sample interval in a soil boring. Technical Methods and Standard Procedures utilized by Terraquest are attached. The SB1 and SB2 soil borings were advanced to a depth of 15 feet below ground level (BGL). The SB3 and SB5 soil borings were advanced to a depth of 10 feet BGL where refusal was encountered. The SB4 soil boring encountered refusal a depth of 4 feet BGL. In each soil boring, soils from the sample intervals (3-5, 5-7, 8-10, and 13-15 feet BGL) were placed in sealable plastic bags and screened for volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) utilizing a Photoionization Detector (PID). The soil lithology encountered during the soil borings was a yellowish-orange, med. stiff Lean Clay (CL) from 0.5 feet to 10 feet BGL and a yellowish-orange hard Lean Clay (CL) from 10 feet BGL to 15 feet BGL. BCA Property Mgmt., LLC 280 Ervin Woods Dr., Kannapolis, Rowan County, NC Page 4 April 14, 2023 The soils to be submitted for analysis were determined by the depth of the UST system component sampled and the PID screening measurements. The soil sample from SB1 was submitted from a depth of 13 to 15 feet BGL. Soil samples from SB2 were submitted from a depth of 10 to 12 feet BGL and 13 to 15 feet BGL. Soil samples from SB3 and SB5 were submitted from a depth of 8 to 10 feet BGL. No soil sample was submitted from the SB4 soil boring. The soil samples collected for analysis were placed in the proper laboratory-prepared sampling containers, labeled with the project name, project number, sample identification, required analysis, and date and time of collection. The samples were immediately placed on ice and analyzed before the expiration of an analytical method’s prescribed holding time. The soil samples were analyzed for total petroleum hydrocarbons (TPH) for low boiling point petroleum hydrocarbons (GRO) and medium to high boiling point petroleum hydrocarbons (DRO) by UVF Trilogy technology. Chain-of-custody documentation was maintained for the soil samples. Soil Sample Analytical Results The North Carolina Department of Environmental Quality Division of Waste Management – UST Section (NCDEQ DWM-UST) Action Limits of 100 milligrams per kilogram (mg/kg) for TPH DRO and 50 mg/kg for TPH GRO were exceeded in the following soil samples:  SB1 @ 13-13.5’ BGL  SB2 @ 10-12’ BGL  SB2 @ 13-15’ BGL  SB3 @ 8-10’ BGL No concentrations above the NCDEQ DWM-UST Action Limits were detected in the SB5 soil sample. The attached Table 1 summarizes the sample depth and detected concentrations of the SB1, SB2, SB3, and SB5 soil samples. The locations of the SB1, SB2, SB3, SB4, and SB5 soil samples are depicted in the attached Figure 2. The complete analytical report is attached. Findings The soil sample analytical results reveal levels of soil contamination above the NCDEQ DWM-UST Action Limits for TPH GRO and DRO in the SB1, SB2, and SB3 soil samples at the 280-gallon heating oil UST and 1,000-gallon plus waste oil UST. BCA Property Mgmt., LLC 280 Ervin Woods Dr., Kannapolis, Rowan County, NC Page 5 April 14, 2023 Recommendations Terraquest recommends the following scope of work to address the findings of the Phase II ESA: 1) Reporting the release incidents to the NCDEQ DWM-UST. 2) Either closing the USTs by removal or in place closure or conducting tank tightness tests on each UST to determine their integrity for future use. 3) Removing the impacted soil surrounding the USTs during their removal and/or completing the regulatory requirements for heating oil and waste oil UST releases to obtain closure of the release incidents. We appreciate the opportunity to provide environmental services. If you have any questions regarding this letter, please call me at (919) 563-9091 or (919) 906-0707. Sincerely, TERRAQUEST ENVIRONMENTAL CONSULTANTS, P.C. Jonathan R. Grubbs, P.G. Vice President Attachments Table 1: Summary of Soil Sampling Results Figure 1: Site Location Map Figure 2: Phase II ESA Sample Location Map Technical Methods and Standard Procedures Analytical Report Table 1 4/5/2023 UV F T R I L O G Y UV F T R I L O G Y Date Collected Sample Depth (feet BGL) SB1 3/30/23 13 -15 2,720 1,610 SB2 3/30/23 10 - 12 1,830 2,795 SB2 3/30/23 13 - 15 1,670 2,795 SB3 3/30/23 8 - 10 320 370 SB5 3/30/23 8 - 10 8.38 <1 100 50 Notes: 1. All results in mg/kg. 2. Bold denotes a compound detection. 3. Grey Shading denotes a TPH Action Limit violation. 4. "<" = less than sample detection limit 5. Sample depths are in feet below ground level. SUMMARY OF SOIL SAMPLING RESULTS Site Name: 280 Ervin Woods Dr., Kannapolis, Rowan County, NC TP H G R O TPH Action Limit Analytical Method Sample ID Contaminant of Concern TP H D R O ONSULTANTS, P.C.CENVIRONMENTAL TECHNICAL METHODS/STANDARD PROCEDURES Equipment Decontamination All soil sampling equipment utilized during site assessment activities is decontaminated according to standard and accepted protocol. Cleaning solutions range from clean potable water to acidic solutions or organic solvents depending on the contaminants present at the site. Equipment utilized at sites, such as hand augers, contaminated with petroleum hydrocarbons, is generally decontaminated with a low-sudsing detergent such as Luiquinox® and triple rinsed with distilled water. Larger equipment, such as drill rigs and associated tools, is steam cleaned. All decontamination procedures are completed within an established decontamination area which is located away from the active study area. Frequency of equipment decontamination depends on the nature of work being performed, but in no case is decontamination performed less frequently than once per test (i.e., soil boring, well installation, sample collection, etc.). Equipment blanks are collected as a quality control measure when required by job specifications. Soil Boring Installation Soil borings are completed using hand-operated sampling tools, truck-mounted drills, or Geoprobe® drilling rigs depending on the depth of sample collection and other site-specific conditions. Hand operated stainless-steel bucket augers are utilized to collect soil samples at regular intervals to determine site stratigraphy and to test for the presence of volatile organic compounds. Samples retrieved from the hand auger are necessarily disturbed during the augering process, but can provide accurate information on soil type and contaminant concentrations when properly interpreted. Soil samples from hand augered borings are generally retrieved at one to two foot intervals. Truck-mounted or Geoprobe® drilling equipment is often utilized when sample retrieval depths exceed twenty feet or subsurface conditions prevent utilization of hand augers (i.e., buried rocks, wood, bricks or other materials occur in the subsurface). Truck-mounted drilling rigs usually retrieve soil via a hollow-stem auger/split spoon collection method. Geoprobe® rigs usually employ a Macro-Core® tube retrieval system. Hollow stem augers provide relatively undisturbed 2-foot cores of soil samples. Soil samples are generally collected at five foot intervals utilizing standard penetration test procedures as defined by the American Society for Testing and Materials (ASTM) or are pushed to the desired depth using the head of the drill rig. The standard penetration test involves driving a 2" outside diameter by 1- 3/8" inside diameter split-spoon sampler a minimum distance of one foot with a 340-lb. slide hammer falling a distance of 30 inches. A Geoprobe® rig is a hydraulically-powered soil probing machine. The probe utilizes static force and percussion to advance a small diameter sampling device into the subsurface. The sampling apparatus provides relatively undisturbed 5-foot cores of soil samples. Soil samples are collected continuously. The Macro-Core® tube contains an inserted poly-vinyl chloride (PVC) liner which retains the soil sample as the tube is driven into the ground. The Macro-Core® tube is decontaminated between each 5-foot sample interval in a soil boring using a Liquinox and tap- water mixture. A new PVC liner is used to collect soil from each sample interval in a soil boring. Soil samples retrieved from the hollow-stem augers or Geoprobe are then carefully described according to the Unified Soil Classification System. Soil descriptions are recorded on a soil boring log. Soil Sampling Soils to be analyzed by a North Carolina-certified laboratory are prepared according to the specified analytical method. Initially, soil samples are removed from the ground using either a hand auger, backhoe bucket, spilt spoon auger, or a Macro-Core® sampling tube. During the removal, care is taken to keep the disturbance of the soil structure to a minimum to reduce the loss of contaminants. Once removed, the samples are placed in the proper sample container for the specified analytical method. For samples collected for the MADEP VPH and EPA Method 8260, a TerraCore® sampler is used to collect one 5-gram allotment of soil. The allotment is placed in methanol-preserved 40 mL vials. Also, one 5-gram allotment of soil is placed into sodium bisulfate- preserved 40 mL vials (one 5-gram allotment per vial, 2 vials per sample) for the 8260 low concentration method. A 250-mL glass jar of the sampled soil is also collected to provide moisture content information. Soils sampled for MADEP EPH, EPA Method 8270 and TPH 5030 and 3550 are placed in a 250-mL glass jar (for MADEP EPH analysis an amber jar is required). TPH 5030 samples are preserved in methanol similar to the 8260 analysis. Field personnel wear new, disposable nitrile gloves during the collection of each sample. The soil samples are labeled with the sample location, sample identification, date and time of collection, and the analytical method. The samples are placed on ice, sent to a laboratory, and analyzed before the expiration of an analytical method’s prescribed holding time. Chain-of-custody documentation is maintained for each sample collected in the field. If the soil is being sampled for volatile or semi-volatile compounds, a portion of the collected soil is placed in a sealable bag and screened for volatile organic vapors. Head screening procedures are described in the following paragraph. Headspace Screening Collected soil samples are routinely tested for the presence of volatile organic compounds (VOCs). After retrieval from the ground, a portion of a soil sample is placed in a sealable plastic bag. The soil samples are then set aside for approximately five minutes so that volatile constituents present in the sample can reach equilibrium concentrations with headspace gases in the bag. Once a suitable time period has passed, the probe of the sampling instrument, typically an Organic Vapor Monitor (OVM) or a Photo Ionization Detector (PID), is inserted into the bag and the relative concentration of total VOCs is measured and permanently recorded in a field note book. VOC concentrations are measured using either a Thermo Electron Corp. Innova Series catalytic OVM or an Ion Science PhoCheck PID. Both the OVM and PID instrumentation are periodically calibrated according to the manufacturer’s recommended procedures. The OVM and PID are qualitative tools employed to detect and estimate the concentration of organic or hydrocarbon vapors. A thin probe is inserted through a small break in the seal of a bagged soil sample. For the OVM, an air sample from the headspace of the bag is drawn through the probe into an internal chamber where the vapors are catalyzed. The concentration of the VOCs is registered on a digital scale in parts per million (ppm). For the PID, an air sample from the headspace of the bag is drawn across the face of a lamp causing the sample to emit photons, the presence of which are converted into a VOC ppm reading that is displayed. Oxygen levels are field calibrated prior to each use. VOC calibration occurs periodically depending upon use by using a span gas of known concentration in a process recommended by the manufacturer. Well Installation/Construction Monitoring wells are installed using hand-operated sampling tools, a truck-mounted drill rig, or a Geoprobe drilling rig depending on the depth of well and other site-specific conditions. All monitoring wells are installed according to the requirements of 15A NCAC 2C-Well Construction Standards. Specifically, individual monitoring wells are constructed of 2-inch diameter, schedule 40 PVC casing riser and screen. The screen interval is generally 10 to 15 feet of machine slotted PVC with a slot size of 0.010". Only flush threaded joints are used. The annulus space around the screen is filled with washed filter pack No. 2 sand. The filter pack extends one to two feet above the top of the screen. A one to two foot-thick bentonite pellet seal is then placed above the filter pack. The remainder of the well annulus is completely filled with a Portland (Type I/II) cement grout mixture. A protective outer steel manhole, locking cap, and concrete pad is installed for each well. Type II Monitoring Well Construction Single-cased monitoring wells are generally used in delineation of groundwater quality within the surficial aquifer. The wells are constructed of 2-inch diameter, schedule 40 PVC casing and screen. The screen interval is generally 10 to 15 feet of machine slotted PVC with a slot size of 0.010". Only flush threaded joints are used. The annulus space around the screen is filled with washed filter pack No. 2 sand. The filter pack extends one to two feet above the top of the screen. A one to two foot-thick bentonite pellet seal is then placed above the filter pack. The remainder of the well annulus is completely filled with a Portland (Type I/II) cement grout mixture. A protective outer steel manhole, locking cap, and concrete pad are installed for each well. Type III Monitoring Well Construction Double-cased monitoring wells are used in the delineation of groundwater quality within a deeper portion of the surficial aquifer or an additional aquifer (e.g. aquitard, bedrock). A four to six-inch outer casing is installed through the surficial aquifer until a sufficient depth or until the deeper aquifer is encountered. The casing is secured with a Portland-grout collar that is tremmied into the annular spaced from the bottom of the bore hole to the surface. Once the grout has sufficiently cured, the bore hole is continued through the bottom of the outer casing to a depth approximately 15 - 20 feet beneath the outer casing. The inner casing is constructed of 2-inch diameter, schedule 40 PVC casing riser and screen. The screen interval is generally 5 to 10 feet of machine slotted PVC with a slot size of 0.010". Only flush threaded joints are used. The annulus space around the screen is filled with washed filter pack No. 2 sand. The filter pack extends one to two feet above the top of the screen. A one to two foot-thick bentonite pellet seal is then placed above the filter pack. The remainder of the well annulus is completely filled with the same Portland grout mixture used in the outer casing. A protective outer steel manhole, locking cap, and concrete pad are installed for each well. Well Development Following installation of each well, surging and pumping or bailing techniques will be used to remove fines from the screened interval. Groundwater is removed from each well until clear water is retrieved or a noticeable reduction in the amount of silt is achieved. Purged groundwater is disposed of in an environmentally safe manner. Groundwater Sampling Petroleum Sites Groundwater samples are collected from temporary or permanent monitoring wells according to established sampling protocol. When multiple monitoring wells or sampling points are sampled, sampling is completed beginning with the least contaminated well to the most contaminated well, if it is known. When permanent monitoring wells for petroleum sites are sampled, the well is purged of a minimum of three well-bore volumes prior to sample collection in order to assure that sampled water is representative of aquifer conditions. In temporary wells, the first water which migrates into the open borehole is sampled. Samples from both temporary and permanent monitoring wells are collected using individually wrapped disposable polyethylene bailers by field personnel wearing disposable nitrile gloves. Only one well is sampled with a given bailer in order to prevent sample cross-contamination. During both well purging and sampling, proper protective clothing and equipment is used and is dependent upon the type and level of contaminants present. Also, field personnel change gloves between different samples to reduce the chance of cross- contamination. Water samples are transferred from the bailer to laboratory-prepared sampling containers using slow emptying devices to reduce the chance of contamination loss through volatilization. Preservatives, such as acids, are provided by the laboratory in pre-prepared containers in which collected samples are placed if in-field preservation is necessary. The samples are labeled with the project name, project number, sample identification, required analysis, and date and time of collection. The samples are placed on ice, shipped to a certified laboratory, and analyzed before the expiration of an analytical method’s prescribed holding time. Chain-of-custody documentation is maintained for each sample collected in the field. Other Groundwater Sampling Protocols When required by state or federal regulations, low-flow groundwater sampling procedures are instituted. Groundwater samples collected in low-flow situations are collected using a peristaltic pump. A peristaltic pump is a type of positive displacement pump. The fluid is contained within a flexible tube fitted inside a circular pump casing. A rotor with a number of rollers attached to the external circumference compresses the flexible tube. As the rotor turns, the part of tube under compression closes thus forcing the fluid to be pumped to move through the tube. Groundwater parameters such as water level drawdown, pH, conductivity, dissolved oxygen (DO) and turbidity. Pumping rate, drawdown, and the time or volume required to obtain stabilization of parameter readings can be used as a future guide to purge the well. Measurements are collected at a pre- pumping established interval (typically five to ten minutes). Once all or a majority of the parameters have stabilized for three successive readings, stabilization has been achieved. In lieu of measuring all five parameters, a minimum subset would include pH, conductivity, and turbidity or DO. Three successive readings should be within ± 0.1 for pH, ± 3% for conductivity, and ± 10% for turbidity and DO. Upon parameter stabilization, sampling is initiated. Sampling flow rate is maintained at the estab- lished purge rate or is adjusted slightly to minimize aeration, bubble formation, turbulent filling of sample bottles, or loss of volatiles due to extended residence time in tubing. The same device used for purging is used to collect the groundwater sample. Generally, volatile parameters are sampled first. The sequence in which samples for inorganic parameters are collected is not determined unless filtered (dissolved) samples are collected. Preservatives, such as acids, are provided by the laboratory in pre-prepared containers in which collected samples are placed if in-field preservation is necessary. The samples are labeled with the project name, project number, sample identification, required analysis, and date and time of collection. The samples are placed on ice, shipped to a certified laboratory, and analyzed before the expiration of an analytical method’s prescribed holding time. Chain-of-custody documentation is maintained for each sample collected in the field. During both well purging and sampling, proper protective clothing and equipment is used and is dependent upon the type and level of contaminants present. Also, field personnel change gloves between different monitoring wells or sampling points to reduce the chance of cross- contamination. When multiple monitoring wells or sampling points are sampled, sampling is completed beginning with the least contaminated well to the most contaminated well, if it is known. Stockpile Sampling The number of composite samples collected from a stockpile or a total quantity of excavated soil is based upon the cubic yardage. One composite sample is collected for every 100 cubic yards of contaminated soil excavated. The volume of a stockpile or total quantity of excavated soil is calculated by approximating the general geometry of a stockpile or estimating the capacity of the dump trucks used for hauling. If a stockpile is sampled, a grid pattern is laid out on the stockpile, dividing the stockpile into segments of approximately 200 cubic yards. Two soil borings are advanced within a grid and three soil samples are collected from each soil boring at various depths. The six soil samples are mixed into a composite sample by a trained TerraQuest technician. If truck loads are sampled, an aliquot sample is collected from the hauling trucks at a frequency based upon the capacity of the hauling trucks. Aliquots are gently mixed into a composite sample by a trained TerraQuest technician. Every effort is made to minimize the loss of contaminants through volatilization. The composited soil samples are jarred in the appropriate laboratory-prepared containers, labeled with the sample location, sample identification, date of collection, time of collection, the analytical method, and the preservative. The samples are placed on ice, shipped to a laboratory, and analyzed before the expiration of an analytical method’s prescribed holding time. Chain-of-custody documentation is maintained for each sample collected in the field. Surface Water Sampling Surface water samples, specifically samples from creeks or streams, are collected from a moving/flowing portion of the creek or stream to ensure that stagnant water is not collected. Field personnel are careful to collect samples from flowing areas that are not so turbulent as to cause a loss of volatile contaminants which might have been contained in the creek’s/stream’s water. Samples are collected by field personnel wearing disposable nitrile gloves. Field personnel change gloves between different locations to reduce the chance of cross-contamination. Samples are collected directly from the appropriate creek or stream location and placed into the appropriate laboratory-prepared containers. Preservatives, such as acids, are provided by the laboratory in pre- prepared containers in which collected samples are placed if in-field preservation is necessary. The samples are labeled with the project name, project number, sample identification, required analysis, and date and time of collection. The samples are cooled on ice to approximately four degrees centigrade, shipped to a certified laboratory, and analyzed before the expiration of an analytical method’s prescribed holding time. Chain-of-custody documentation is maintained for each sample collected in the field. Potable Well Sampling Groundwater samples from potable wells are collected from sampling points, typically spigots, located in the closest proximity to the potable well pump house as possible. Prior to sample collection, the water is run for a sufficient amount of time to purge the bladder tank and assure that sampled water is representative of aquifer conditions. Once purged, the flow rate is reduced and samples are placed in the appropriate laboratory prepared containers with the appropriate acid preservatives added if preservation of the sample is necessary. The samples are labeled with the project name, project number, sample identification, required analysis, and date and time of collection. The samples are placed on ice, shipped to a laboratory, and analyzed before the expiration of an analytical method’s prescribed holding time. Chain-of-custody documentation is maintained for each sample collected in the field. Public Water Supply Line Sampling Groundwater samples from public water supply lines are collected from sampling points, typically spigots. To sample the spigot, the flow rate is reduced and samples are placed in the appropriate laboratory prepared containers. The samples are labeled with the sample location, sample identification, date of collection, time of collection, and required analytical method. The samples are placed on ice, shipped to a laboratory, and analyzed before the expiration of an analytical method’s prescribed holding time. Chain-of-custody documentation is maintained for each sample collected in the field. Air Sampling Air samples are collected with the aide of a manually operated MityVac® pump manufactured by Pristech, Inc. The air sampling process begins by connecting a length of rubber hose from the MityVac® pump to the port to be sampled, or by hanging the hose inside of an emissions stack in such a manner as to ensure no outside air causes dilution. Another length of hose is fixed to the outlet port of the pump and is connected to a new Tedlar bag. Once the pump is hooked up, a valve on the Tedlar collection bag is opened and air is manually forced into the bag by the pumping action of sampling personnel. Field Measurements Field measurements taken to determine the pH, conductivity, temperature, and dissolved oxygen concentration of a particular groundwater sample are taken directly after a particular monitoring well has been adequately purged. This ensures that the groundwater parameter data collected is representative of the aquifer conditions at a given location. Once purging of the monitoring well is complete, the decontaminated probe head and cord of the appropriate unit is lowered into the required monitoring well. If the depth to water in a specific monitoring well is greater than the length of cord for a particular unit, a new, disposable bailer is slowly lowered into the appropriate monitoring well and a representative groundwater sample is retrieved. A slow pouring device is fitted onto the end of the disposable bailer and the sample is slowly poured into a new, disposable plastic cup. Groundwater parameter data are then collected from the groundwater in the cup using the required unit. For pH, conductivity, and temperature, a Hanna Instruments Model 991300 portable meter is utilized. This unit is periodically calibrated and maintained in accordance with the unit’s operations manual by field personnel. Prior to data collection, the unit is properly decontaminated to prevent cross-contamination. The unit is decontaminated between each sample. The procedure used for sample measurement involves lowering the meter’s probe into the new, disposable cup containing the groundwater sample to be measured and slowly stirring the probe to force groundwater across the probe’s membrane. The measurements displayed by the meter are then recorded. For dissolved oxygen concentration measurements, a YSI® Model 55 Handheld Dissolved Oxygen System is utilized. This unit is periodically calibrated and maintained in accordance with the unit’s operations manual by field personnel. Prior to data collection, the unit is properly decontaminated to prevent cross-contamination. The unit is decontaminated between each sample. The procedure used for sample measurement involves adjusting the unit for the correct altitude where the sampling will take place and adjusting the reported units desired. Once this is done, the unit’s probe is inserted into the groundwater sample to be measured and the probe is slowly stirred to force the groundwater across the probe’s membrane. The measurements displayed by the unit are then recorded. For turbidity measurements, a Hach 2100P Portable Turbidity meter or equal equivalent is utilized. The unit is calibrated prior to use in accordance with the unit’s operations manual by field personnel. Groundwater samples are collected in glass containers for measurement by the instrument. The glass containers are washed with bottled-water between each measurement collection. Once the sample is collected and inserted into the instrument, the measurements displayed by the instrument are then recorded. UVF TRILOGY ANALYTICAL REPORT Project Name: 280 Ervin Woods Drive Project Number: 03323 Date: 3/31/2023 Standard Technical Procedures The UVF TRILOGY instrument is a fixed-wavelength fluorometer but uses deep UV LEDS to detect monoaromatic and polyaromatic hydrocarbons. SITELAB’s CAL-025 GRO Module is used to detect volatile petroleum hydrocarbons in the C6 to C10 range. This test matches well to EPA Methods for GRO, BTEX, BPH or VOC’s using GC/FID instrumentation. SITELAB’s CAL-042 EDRO Module is used to detect petroleum hydrocarbons in the C10 to C36 diesel and oil range. This test matches well to EPA methods for TPH, EPH, DRO, and others using GC-FID instrumentation. Prior to field usage, the UVF TRILOGY is calibrated with five calibration standard solutions per targeted analyte. Soil samples are weighed to the nearest gram (i.e. 5.0 g) and added to a 1-ounce HDPE Nalgene bottle with a measured amount of laboratory grade methanol to the nearest mL (i.e. 10 mL) to create a sample extract. After addition of both the soil and methanol, the bottle is agitated for several minutes. Next, the sample rests for several minutes allowing for the soil and methanol extract to separate. After ample resting time, the methanol extract is collected with a syringe. A filter is connected to the end of the syringe and dispensed into a clean sample test tube. The test tube is labeled with sample ID and extract dilution factor (i.e. 2X). Known amounts of extract are pipetted into a second test tube and diluted with methanol. The sample ID and dilution factor are labeled on the test tube (i.e. 100X). Samples are placed into a clean cuvette and carefully inserted into the selected UV Module. Prior to analyzing the sample, the stored calibration that matches the UV Module being used, is selected. The UVF TRILOGY produces a result that when multiplied to the dilution factor equals the true TPH value. Quenching occurs when the detector is swamped by too many or certain type of hydrocarbons, producing low or negative concentrations. The sample is tested at multiple dilutions to confirm the results are linear and accurate. Solvent blank samples are periodically analyzed to confirm the solvent is clean and the calibration of the machine is maintained. UVF Analytical Report Project Name 280 Ervin Woods Dr Project Number 03323 Method UVF Trilogy Sample Name Sample Depth Sample Date Analyte Name Dilution Result MDL Units SB1 13-15 3/30/2023 DRO 500 2720 50 mg/kg SB1 13-15 3/30/2023 GRO 500 1610 250 mg/kg Friday, March 31, 2023 Page 1 of 4 Project Name 280 Ervin Woods Dr Project Number 03323 Method UVF Trilogy Sample Name Sample Depth Sample Date Analyte Name Dilution Result MDL Units SB2 10-12 3/30/2023 DRO 500 1830 50 mg/kg SB2 10-12 3/30/2023 GRO 500 2795 250 mg/kg SB2 13-15 3/30/2023 DRO 500 1670 50 mg/kg SB2 13-15 3/30/2023 GRO 500 2795 250 mg/kg Friday, March 31, 2023 Page 2 of 4 Project Name 280 Ervin Woods Dr Project Number 03323 Method UVF Trilogy Sample Name Sample Depth Sample Date Analyte Name Dilution Result MDL Units SB3 8-10 3/30/2023 DRO 500 320 50 mg/kg SB3 8-10 3/30/2023 GRO 500 370 250 mg/kg Friday, March 31, 2023 Page 3 of 4 Project Name 280 Ervin Woods Dr Project Number 03323 Method UVF Trilogy Sample Name Sample Depth Sample Date Analyte Name Dilution Result MDL Units SB5 8-10 3/30/2023 DRO 2 8.38 0.2 mg/kg SB5 8-10 3/30/2023 GRO 2 <1 1 mg/kg Friday, March 31, 2023 Page 4 of 4