Alexandra C. Adams 20250321 tabular digital data Denver, Colo. U.S. Geological Survey https://doi.org/10.5066/P1CGQM6Z The U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (EPA), collected groundwater-level altitude and water-quality data from selected monitoring wells at the Petro-Chemical Systems, Inc. (Turtle Bayou) Superfund site in Liberty County, Texas on April 29 and November 13, 2024. These data were collected to obtain information that could be used to provide an update on the status of groundwater contamination at the site. This data release documents the groundwater-level altitudes, field properties, and water-quality data obtained in April and November 2024 from six of the 11 on-site monitoring wells where similar data were collected by the USGS during sampling that took place in August and September 2020 (Braun and Becher 2022; Lucena, 2022). The same six wells that were sampled in April and November 2024 were also sampled in April 2023 (Adams, 2023). Each water-quality sample was analyzed for a suite of volatile and semivolatile organic compounds. This data release documents water-quality data collected in April and November 2024 pertaining to the status of groundwater within the boundaries of the Petro-Chemical Systems, Inc. (Turtle Bayou) Superfund site in Liberty County, Texas. In addition to the water-quality data from the groundwater samples collected at the site, this data release also documents the analytical results from the quality-control samples that were collected or prepared in conjunction with the environmental samples. 20240429 20241119 ground condition Complete None planned -94.6955000 -94.6951000 29.9192000 29.9186000 ISO 19115 Topic Category geoscientificInformation None groundwater Environmental Protection Agency water quality Superfund volatile organic compounds semivolatile organic compounds USGS Metadata Identifier USGS:66562a4ad34ef3137d35ea4b None Liberty County Turtle Bayou Texas USA None. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Oklahoma-Texas Water Science Center U.S. Geological Survey Public Information Officer mailing and physical

1505 Ferguson Lane

Austin Texas 78754 512-927-3500 otpublicinfo@usgs.gov This dataset was prepared by the USGS in cooperation with the U.S. Environmental Protection Agency (EPA). Christopher L. Braun Kent D. Becher 2022 publication Scientific Investigations Report 2022-5104 Reston, Va. U.S. Geological Survey 17 p. https://doi.org/10.3133/sir20225104 Zulimar Lucena 2022 dataset Denver, Colo. U.S. Geological Survey https://doi.org/10.5066/p9gx8yu7 Alexandra C. Adams 2023 dataset Denver, Colo. U.S. Geological Survey https://doi.org/10.5066/p9y3ec24 Quality-control samples were collected to quantify the bias and variability in the environmental sample dataset. The collection, processing, transport, and analysis of environmental samples introduces analytical uncertainty that can be quantified by the use of replicate and blank samples (Mueller and others, 2015). Quality-control samples collected for volatile organic compound (VOC) analysis on April 29, 2024 were submitted by USGS project personnel to the EPA Region 6 Laboratory in Houston, Tex. Quality-control samples collected for semivolatile organic compound (SVOC) analysis on April 29, 2024, were submitted by USGS project personnel to the CHEMTEX Laboratory in Port Arthur, Tex. Quality-control samples collected for VOC and SVOC analysis on November 13, 2024, were submitted by USGS project personnel to the EPA Region 6 Laboratory in Houston, Tex. On April 29, 2024, one field-replicate sample was collected from monitoring well MW-33 for the analysis of VOCs and SVOCs. One trip-blank sample (a certified blank solution poured into the same type of bottle used for collecting VOC samples) was kept with the environmental VOC samples from sample collection through all processing and shipping steps culminating with laboratory analysis for VOCs. One field-blank sample (a certified blank solution used to evaluate the adequacy of field and laboratory protocols) was collected before the environmental sample from monitoring well MW-191R was collected and was analyzed for VOCs and SVOCs. One laboratory-blank sample for VOC analysis and one laboratory-blank sample for SVOC analysis were prepared and analyzed by the respective analytical laboratories to evaluate the adequacy of laboratory processing and analysis protocols. Two VOCs (methyl tert-butyl ether [MTBE] and 1,1-dichloroethane) were detected in both environmental and replicate samples collected from monitoring well MW-33 on April 29, 2024. The relative percent differences (RPDs) for MTBE and 1,1-dichloroethane were 1.3 and 0 percent, respectively. No SVOCs were detected in the environmental or replicate groundwater samples collected from monitoring well MW-33. No VOCs or SVOCs were detected in any of the blank samples collected (or prepared) and analyzed in conjunction with the environmental samples collected on April 29, 2024. On November 13, 2024, one field-replicate sample was collected from monitoring well MW-191R for the analysis of VOCs and SVOCs. One trip-blank sample was kept with the environmental VOC samples from sample collection through all processing and shipping steps culminating with laboratory analysis for VOCs. One field-blank sample was collected before the environmental sample from monitoring well MW-191R was collected and was analyzed for VOCs and SVOCs. One laboratory-blank sample for VOC analysis and one laboratory-blank sample for SVOC analysis were analyzed by the analytical laboratory. No VOCs or SVOCs were detected in the environmental or replicate groundwater samples collected from monitoring well MW-191R. No VOCs or SVOCs were detected in any of the blank samples collected (or prepared) and analyzed in conjunction with the environmental samples collected on November 13, 2024. All data values were peer reviewed. Data were checked to ensure all results were within expected ranges. Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. No formal horizontal positional accuracy tests were conducted No formal vertical positional accuracy tests were conducted U.S. Geological Survey Unknown publication Reston, Va. U.S. Geological Survey https://doi.org/10.3133/twri09 Digital and/or Hardcopy Unknown publication date USGS (variously dated) Description of USGS standard methods and protocols for groundwater sample field collection. Robert W. Puls Michael J. Barcelona 1996 publication Ground Water Issue EPA/540/S-95/504 https://cfpub.epa.gov/si/si_public_record_report.cfm?Lab=NRMRL&dirEntryId=126106 Digital and/or Hardcopy 1996 publication date Puls and Barcelona (1996) Description of EPA low-flow groundwater sampling procedures in monitoring wells. David K. Mueller Terry L. Schertz Jeffrey D. Martin Mark W. Sandstrom 2015 publication Techniques and Methods 4-C4 Reston, Va. US Geological Survey https://doi.org/10.3133/tm4C4 Digital and/or Hardcopy 2015 publication date Mueller and others (2015) Description of USGS techniques and methods for the collection and analysis of field quality-control data in environmental monitoring. U.S. Environmental Protection Agency 2018 publication https://www.epa.gov/sites/default/files/2018-06/documents/method_8260d_update_vi_final_06-11-2018.pdf Digital and/or Hardcopy 2018 revision date EPA (2018a) Description of analytical laboratory methods to determine volatile organic compound concentrations in water. U.S. Environmental Protection Agency 2018 publication https://www.epa.gov/sites/default/files/2020-10/documents/method_8270e_update_vi_06-2018_0.pdf Digital and/or Hardcopy 2018 revision date EPA (2018b) Description of analytical laboratory methods to determine semivolatile organic compound concentrations in water. Hach 2021 publication https://my.hach.com/2100q-portable-turbidimeter-epa-0-1000-ntu/product-downloads?id=59428402828 Digital and/or Hardcopy 2021 publication date HACH (2021) User manual describing how to calibrate and use the portable Hach turbidimeter to collect turbidity measurements during groundwater sampling. In-Situ 2024 publication https://in-situ.com/pub/media/support/documents/Aqua-TROLL-600-Manual.pdf Digital and/or Hardcopy 2024 publication date In-Situ (2024) Operator's manual describing how to calibrate and use the multiparameter In-Situ Aqua Troll 600 multiparameter sonde to measure water temperature, specific conductance, pH, and dissolved oxygen during groundwater sampling. EA Engineering, Science, and Technology, Inc. 2018 publication https://semspub.epa.gov/work/06/100012070.pdf Digital and/or Hardcopy 2018 publication date EA Engineering, Science, and Technology, Inc. (2018) This report provides the altitude of the measuring point (top of monitoring well casing) referenced to the North American Vertical Datum of 1988 (NAVD88) at each well where a groundwater sample was collected. William L. Cunningham Charles W. Schalk 2011 publication Techniques and Methods 1-A1 Reston, Va. U.S. Geological Survey https://doi.org/10.3133/tm1a1 Digital and/or Hardcopy 2011 publication date Cunningham and Schalk (2011) This report describes procedures and guidelines developed by U.S. Geological Survey for collecting accurate and reliable groundwater-level data. Groundwater samples were collected from six monitoring wells by the USGS at the Petro-Chemical Systems, Inc. (Turtle Bayou) Superfund site in Liberty County, Tex., on April 29, 2024, and November 13, 2024. Groundwater samples were collected in accordance with procedures and protocols described in Puls and Barcelona (1996) and the USGS National Field Manual for the Collection of Water-Quality Data (USGS, variously dated). Prior to sample collection, a static water-level was measured from the top of the casing for each well (Cunningham and Schalk, 2011). Field properties, including water temperature, pH, specific conductance, and dissolved oxygen, were measured using a multi-parameter sonde (In-Situ Aqua TROLL 600 Multiparameter Sonde; In-Situ, 2024) by pumping groundwater from the well into a flow-thru cell attached to the sonde using a peristaltic pump. Turbidity was measured with a portable HACH 2100Q turbidimeter (HACH, 2021). Once field properties stabilized, VOC and SVOC samples were collected. After sample collection on April 29, 2024, samples collected for VOC analysis were prepared for transport to the EPA Region 6 Laboratory in Houston, Tex. and samples collected for SVOC analysis were prepared for shipment to the CHEMTEX Laboratory in Port Arthur, Tex. After sample collection on November 13, 2024, samples collected for VOC and SVOC analysis were prepared for shipment to the EPA Region 6 Laboratory in Houston, Tex. Samples were analyzed for VOCs using Method 8260 (EPA, 2018a) and were analyzed for SVOCs using Method 8270 (EPA, 2018b). Puls and Barcelona (1996) USGS (variously dated) Cunningham and Schalk (2011) In-Situ (2024) HACH (2021) EPA (2018a) EPA (2018b) 2024 0.0001 0.0001 Decimal degrees North American Datum of 1983 Geodetic Reference System 1980 6378137.000000 298.257222 North American Vertical Datum of 1988 0.01 feet Attribute values PETROCHEM_WELL_INFO.txt Tab-delimited text file containing well location and well construction information at the Petro-Chemical Systems Inc. (Turtle Bayou) Superfund Site. Groundwater levels measured in conjunction with the collection of water-quality samples in April and November 2024 are included in this file. U.S. Geological Survey WELL_ID Monitoring well identifier. U.S. Geological Survey The monitoring well identifier assigned by the driller. LATITUDE Latitude of the monitoring well. U.S. Geological Survey 29.9186 29.9192 decimal degrees 0.0001 LONGITUDE Longitude of the monitoring well. U.S. Geological Survey -94.6955 -94.6951 decimal degrees 0.0001 GWLEVEL_DATE The date the groundwater-level measurement was made. U.S. Geological Survey 4/29/2024 11/13/2024 month/day/year GWLEVEL_TIME The time the groundwater-level measurement was collected. U.S. Geological Survey 8:45 15:47 hour:minute GWLEVEL_TIMEZONE The time zone in which the groundwater-level measurement was collected. U.S. Geological Survey CDT The groundwater level measurement was collected during daylight savings time, or Central Daylight Time. U.S. Geological Survey CST The groundwater level measurement was collected during standard time, or Central Standard Time. U.S. Geological Survey MP_ft_ALS Length of well casing extending above land surface datum. The groundwater-level was measured from the top of the well casing (hereinafter referred to as a "measuring point"). U.S. Geological Survey 1.70 2.87 feet 0.01 WELLDEPTH_ft_MP Depth of the monitoring well below the measuring point obtained from EA Engineering, Science, and Technology, Inc. (2018) for all wells except MW-33, which was obtained in the form of written communication from Laura Hunt, the EPA remedial project manager for the site. U.S. Geological Survey 31.7 47.6 feet 0.1 CASINGDIAMETER_in The inner diameter of the monitoring well casing. U.S. Geological Survey 2 4 inches 1 SCREENEDINTERVAL_ft The depth range to the upper and lower extents of the screened interval within the monitoring well relative to land surface datum, in feet. Upper and lower depths are separated by a dash (-). Screened interval information was obtained from EA Engineering, Science, and Technology, Inc. (2018) for all wells except MW-33, which was obtained in the form of written communication from Laura Hunt, the EPA remedial project manager for the site. U.S. Geological Survey The range of the screened interval, in feet. MP_ALTITUDE_ftNAVD88 The altitude of the measuring point (top of well casing) referenced to NAVD88; obtained from EA Engineering, Science, and Technology (2018). U.S. Geological Survey 41.03 42.34 feet 0.01 DEPTHTOGW_ft_MP Measured depth to groundwater from the measuring point of the monitoring well. U.S. Geological Survey 17.65 20.82 feet 0.01 GW_ALTITUDE_ftNAVD88 The groundwater-level altitude (referenced to NAVD88) that was calculated by subtracting the depth to groundwater (measured from the measuring point) from the altitude of the measuring point (top of well casing): [MP_ALTITUDE_ftNAVD88 - DEPTHTOGW_ft_MP]. U.S. Geological Survey 21.49 23.76 feet 0.01 PETROCHEM_FIELD_PROPERTIES.txt Tab-delimited text file containing field-property measurements collected before water-quality samples were collected at the Petro-Chemical Systems Inc. (Turtle Bayou) Superfund Site in April and November 2024. U.S. Geological Survey WELL_ID Monitoring well identifier. U.S. Geological Survey The monitoring well identifier assigned by the driller. DATE The date the field-property measurement was made. U.S. Geological Survey 4/29/2024 11/13/2024 month/day/year TIME The time the field-property measurement was made. U.S. Geological Survey 9:03 16:46 hour:minute TIME_ZONE The time zone in which the field-property measurement was made. U.S. Geological Survey CDT The field-property measurement was collected during daylight savings time, or Central Daylight Time. U.S. Geological Survey CST The field-property measurement was collected during standard time, or Central Standard Time. U.S. Geological Survey FIELD_PROPERTY_NAME The name of the field property. U.S. Geological Survey Water temperature The temperature of the water measured prior to sample collection. U.S. Geological Survey Specific conductance The specific conductance of the water measured prior to sample collection. U.S. Geological Survey pH The pH of the water measured prior to sample collection. U.S. Geological Survey Dissolved oxygen The dissolved oxygen concentration of the water measured prior to sample collection. U.S. Geological Survey Turbidity The turbidity of the water measured prior to sample collection. Producer defined Pumping rate The rate at which groundwater was pumped from the monitoring well prior to sample collection. U.S. Geological Survey Depth to water The depth to groundwater in the monitoring well prior to sample collection measured from the top of the well casing. U.S. Geological Survey VALUE The value of the measured field property. U.S. Geological Survey NA The value for the field property was not measured. U.S. Geological Survey 0.20 2,721 various units of measure, see "UNIT' field within this dataset UNIT The unit of measure associated with the "FIELD_PROPERTY_NAME" field within this dataset. U.S. Geological Survey degrees Celsius Unit of measure associated with "Water temperature" in the "FIELD_PROPERTY_NAME" field within this dataset. U.S. Geological Survey microsiemens per centimeter at 25 degrees Celsius Unit of measure associated with "Specific conductance" in the "FIELD_PROPERTY_NAME" field within this dataset. U.S. Geological Survey standard units Unit of measure associated with "pH" in the "FIELD_PROPERTY_NAME" field within this dataset. U.S. Geological Survey milligrams per liter Unit of measure associated with "Dissolved oxygen" in the "FIELD_PROPERTY_NAME" field within this dataset. U.S. Geological Survey nephelometric turbidity unit Unit of measure used to express the measured value associated with "Turbidity" in the "FIELD_PROPERTY_NAME" field within this dataset. U.S. Geological Survey liters per minute Unit of measure associated with "Pumping rate" in the "FIELD_PROPERTY_NAME" field within this dataset. U.S. Geological Survey feet from top of casing Unit of measure associated with "Depth to water" in the "FIELD_PROPERTY_NAME" field within this dataset. U.S. Geological Survey PETROCHEM_ORGANICS_DATA.txt Tab-delimited text file containing VOC and SVOC analytical results for the environmental groundwater samples collected at the Petro-Chemical Systems Inc. (Turtle Bayou) Superfund Site in 2024. U.S. Geological Survey WELL_ID Monitoring well identifier. U.S. Geological Survey The monitoring well identifier assigned by the driller. SAMPLE_DATE The date the environmental groundwater sample was collected. U.S. Geological Survey 4/29/2024 11/13/2024 month/day/year SAMPLE_TIME The time the environmental groundwater sample was collected. U.S. Geological Survey 9:30 17:00 hour:minute SAMPLE_TIMEZONE The time zone in which the sample was collected. U.S. Geological Survey CDT The sample was collected during daylight savings time, or Central Daylight Time. U.S. Geological Survey CST The sample was collected during standard time, or Central Standard Time. U.S. Geological Survey ANALYTE_GROUP Analyte group associated with a suite of organic compounds identified in the "ANALYTE" field within this dataset. U.S. Geological Survey Semivolatile organic compound The analyte (associated with the 'ANALYTE' field in this dataset) is a semivolatile organic compound. The concentration of the analyte in the sample was measured by using EPA Method 8270 (EPA, 2018b). Both laboratories that analyzed for semivolatile organic compounds in conjunction with the two sampling events during 2024 used this method. EPA, 2018b Volatile organic compound The analyte (associated with the 'ANALYTE' field in this dataset) is a volatile organic compound. The concentration of the analyte in the sample was measured by using EPA Method 8260 (EPA, 2018a). EPA, 2018a ANALYTE The name of the VOC or SVOC analyzed by the laboratory. U.S. Geological Survey Name of the individual VOC or SVOC analyzed by the laboratory. REMARK_CD The remark code associated with the "RESULT_ug/L" field within this dataset. U.S. Geological Survey NA No associated remark code. various laboratories < Less than, which indicates that the analyte was not detected at a concentration equal to or greater than the laboratory reporting limit. various laboratories RESULT_ug/L The concentration for a detected organic compound (indicated by "NA" in the “REMARK_CD” field within this dataset) or the reporting limit for a non-detected organic compound (indicated by "<" in the “REMARK_CD” field within this dataset). U.S. Geological Survey 0.5 20.0 micrograms per liter 0.1 QUALIFIER Data qualifier assigned to a reported value by either the EPA Region 6 Laboratory (for VOCs analyzed in the April and November 2024 sampling efforts and SVOCs analyzed from the November 2024 samples) or the CHEMTEX Laboratory (for SVOCs analyzed from the April 2024 samples). U.S. Geological Survey NA No data qualifiers are associated with the reported value. U.S. Geological Survey LJ "The reported value for this analyte was below the reported quantitation limit and is an estimated value." U.S. Geological Survey RL "The reporting limit for this analyte was raised because absence or presence at the routine or lower value could not be verified." U.S. Geological Survey PETROCHEM_QC_DATA.txt Tab-delimited text file containing VOC and SVOC analytical results for quality-control groundwater samples (including two field-replicate samples, two field-blank samples, two trip-blank samples, and four laboratory-blank samples) either collected or prepared in conjunction with the analysis of the environmental samples collected at the Petro-Chemical Systems Inc. (Turtle Bayou) Superfund Site in 2024. U.S. Geological Survey SAMPLE_ID The quality-control sample identifier, which includes 'REP' for the field-replicate sample or 'FB' for the field-blank sample or is named 'Lab_Blank' for a laboratory-blank sample or 'Trip_Blank' for a trip-blank sample. Field-replicate and field-blank samples are associated with the environmental sample collected at a specific monitoring well on the same date that the quality control sample in question was collected. As a result, the SAMPLE_IDs associated with field-replicate and field-blank samples begins with the WELL_ID specified in PETROCHEM_ORGANICS_DATA.txt of the associated monitoring well in question. U.S. Geological Survey MW-33_REP The sample identifier assigned to the field-replicate sample collected from well MW-33 in April 2024. U.S. Geological Survey MW-191R_FB The sample identifier assigned to the field-blank samples that were collected in either April or November 2024 before the environmental sample from well MW-191R was collected. U.S. Geological Survey Trip_Blank The sample identifier assigned to the trip-blank samples collected by the USGS in either April or November 2024. U.S. Geological Survey Lab_Blank The sample identifier assigned to the laboratory-blank samples that were analyzed for SVOCs or VOCs in May or November 2024. U.S. Geological Survey MW191R_REP The sample identifier assigned to the field-replicate sample collected from well MW-191R in November 2024. U.S. Geological Survey SAMPLE_DATE The date the quality-control groundwater sample was collected (for field-blank and field-replicate samples), prepared (for trip-blank samples), or analyzed (for laboratory-blank samples). U.S. Geological Survey 4/29/2024 11/19/2024 month/day/year SAMPLE_TIME The time at which the quality-control groundwater sample was collected or prepared or the time that the laboratory blank was analyzed. U.S. Geological Survey 7:49 16:25 hour:minute SAMPLE_TIMEZONE The time zone in which the quality-control groundwater sample was collected or prepared or the time zone in which the laboratory blank was analyzed. U.S. Geological Survey CDT The sample was collected, prepared, or analyzed during daylight savings time, or Central Daylight Time. U.S. Geological Survey CST The sample was collected, prepared, or analyzed during standard time, or Central Standard Time. U.S. Geological Survey ANALYTE_GROUP Analyte group associated with a suite of organic compounds identified in the "ANALYTE" field within this dataset. U.S. Geological Survey Semivolatile organic compound The analyte (associated with the 'ANALYTE' field in this dataset) is a semivolatile organic compound. The concentration of the analyte in the sample was measured by using EPA Method 8270 (EPA, 2018b). Both laboratories that analyzed for semivolatile organic compounds in conjunction with the two sampling events during 2024 used this method. U.S. Geological Survey Volatile organic compound The analyte (associated with the 'ANALYTE' field in this dataset) is a volatile organic compound. The concentration of the analyte in the sample was measured by using EPA Method 8260 (EPA, 2018a). U.S. Geological Survey ANALYTE The name of the VOC or SVOC analyzed by the laboratory. U.S. Geological Survey Name of the individual VOC or SVOC analyzed by the laboratory. REMARK_CD The remark code associated with the "RESULT_ug/L" field within this dataset. U.S. Geological Survey NA No associated remark code. U.S. Geological Survey < Less than, which indicates that the analyte was not detected above the laboratory reporting limit. U.S. Geological Survey RESULT_ug/L The concentration for a detected organic compound (indicated by "NA" in the “REMARK_CD” field within this dataset) or the reporting limit for a non-detected organic compound (indicated by "<" in the “REMARK_CD” field within this dataset). No data qualifiers are associated with any of the concentration or reporting limit data contained in the "RESULT_ug/L" field. U.S. Geological Survey 0.5 21.1 micrograms per liter 0.1 GS ScienceBase U.S. Geological Survey mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the USGS, no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Although these data have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Digital Data https://doi.org/10.5066/P1CGQM6Z None 20250321 Alexandra C. Adams U.S. Geological Survey Hydrologist mailing and physical

19241 David Memorial Drive, Ste. 180

Shenandoah Texas 77385 US 936-697-3440 acadams@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998