30-Attachment MM - Report File, Phase II Environmental Site Assessment.pdf

PHASE II ENVIRONMENTAL SITE

ASSESSMENT

HCFCD PROJECT ID B509-04-00-E001

RED BLUFF REGIONAL DETENTION BASIN (C-07)

WEST FAIRMONT PARKWAY & GENOA RED BLUFF ROAD

LA PORTE, HARRIS COUNTY, TEXAS

January 14, 2022 Project No. 92207764.T6

Prepared for:

iGET Services LLC

10039 Bissonnet Street, Suite 336 Houston, TX 77036

Prepared by:

Terracon Consultants, Inc.

11555 Clay Road, Suite 100 Houston, Texas 77043

TABLE OF CONTENTS

Page No.

EXHIBITS

Exhibit 1 - Site Vicinity Map Exhibit 2 - Site Plan

TABLES

Table 1 - Summary of Soil Analytical Results Table 2 - Summary of Groundwater Analytical Results

1.0 INTRODUCTION

1.1 Scope of Work

1.2 Standard of Care

1.3 Additional Scope Limitations

1.4 Reliance

2.0 FIELD ACTIVITIES

2.1 Land Clearing

2.2 Geophysical Survey

2.2 Soil Borings and Temporary Groundwater Sampling Points

2.3 Soil and Groundwater Sampling

3.0 LABORATORY ANALYTICAL PROGRAM

4.0 INVESTIGATION RESULTS AND EVALUATION

4.1 Soil Samples

4.2 Groundwater Samples

5.0 FINDINGS AND RECOMMENDATIONS

APPENDICES

Appendix A - Geophysical Survey Report Appendix B - Site Photographs Appendix C - Boring Logs Appendix D - Analytical Laboratory Reports Appendix E - Tier 2 PCL Calculations for Arsenic and Lead

Responsive ■ Resourceful ■ Reliable 1

PHASE II ENVIRONMENTAL SITE ASSESSMENT

HCFCD PROJECT ID B509-04-00-E001

RED BLUFF REGIONAL DETENTION BASIN (C-07)

WEST FAIRMONT PARKWAY & GENOA RED BLUFF ROAD

LA PORTE, HARRIS COUNTY, TEXAS

Terracon Project No. 92207764.T6 January 14, 2022

1.0 INTRODUCTION

1.1 Scope of Work

Terracon Consultants, Inc. (Terracon) conducted a Phase II Environmental Site Assessment (Phase II ESA) at the site. The site consists of two adjacent proposed detention basins (B509-04- 00 and B509-03-00) located in the southwest and southeast corners of the intersection of West Fairmont Parkway and Genoa Red Bluff Road, in La Porte, Harris County, Texas. The site consists of approximately 326 acres of undeveloped, wooded land, and includes the corresponding segment of the Harris County Flood Control District (HCFCD) channel to the east (Spring Gully – B109-00-00). The proposed detention basins are bisected by Genoa Red Bluff Road and an overhead electrical power line easement. Based on a review of the historical information, the site primarily consisted of undeveloped land with residential development from at least 1916 until the early 1970s when residential structures were no longer apparent. The site has been undeveloped land since that time. In the early 1940s, oil/gas exploration activity was apparent on the southeast portion of the site and pipeline easements have transected the northwestern and northern portions of the site since the early 1950s and mid-1990s, respectively.

The LSI was conducted in accordance with Terracon Proposal No. P92207764 dated October 13, 2021. The scope of services for this LSI was based on the results of Terracon’s Phase I Environmental Site Assessment (ESA - Project No. 92207764.T4, dated September 10, 2021), which identified the following recognized environmental condition (REC) and/or site concern.

n Review of on-line Railroad Commission of Texas (RRC) records identified one dry hole (a well that did not encounter sufficient quantities of oil or gas for production) on the southeast portion of the current site limits. At the time of the site reconnaissance, no apparent active exploration and production (E&P) well pad sites were observed on the site. The use of drilling mud and management of produced fluids (i.e. produced water [brine], crude oil, and/or condensate) typically associated with oil/gas exploration sites commonly lead to soil and groundwater impact from metals and/or petroleum hydrocarbons above RRC action levels. Based on the frequency of releases associated with oil/gas exploration

Phase II Environmental Site Assessment HCFCD Project ID# B509-04-00-E001 ■ La Porte, Harris County, Texas January 14, 2022 ■ Terracon Project No. 92207764.T6

Responsive ■ Resourceful ■ Reliable 2 activities, potential releases from the apparent historical on-site oil/gas exploration activities appear to constitute a REC to the site.

The objective of the LSI was to assess the presence of chemicals commonly associated with oil/gas E&P activities in on-site soil and groundwater. The LSI included a geophysical survey to locate the well casing associated with the dry hole and the advancement of four shallow soil borings and one deep soil boring for the collection and analysis of soil samples. The deep soil boring was converted into a temporary groundwater sampling point (TSP) for collection and analysis of a groundwater sample.

1.2 Standard of Care

Terracon’s services were performed in a manner consistent with generally accepted practices of the profession undertaken in similar studies in the same geographical area during the same time period. Terracon makes no warranties, either express or implied, regarding the findings, conclusions or recommendations. Please note that Terracon does not warrant the work of laboratories, regulatory agencies or other third parties supplying information used in the preparation of the report. These LSI services were performed in accordance with the scope of work agreed with you, our client, as reflected in our proposal and were not restricted by ASTM E1903-11.

1.3 Additional Scope Limitations

Findings, conclusions and recommendations resulting from these services are based upon information derived from the on-site activities and other services performed under this scope of work; such information is subject to change over time. Certain indicators of the presence of hazardous substances, petroleum products, or other constituents may have been latent, inaccessible, unobservable, nondetectable or not present during these services, and we cannot represent that the site contains no hazardous substances, toxic materials, petroleum products, or other latent conditions beyond those identified during this LSI. Subsurface conditions may vary from those encountered at specific borings or wells or during other surveys, tests, assessments, investigations or exploratory services; the data, interpretations, findings, and our recommendations are based solely upon data obtained at the time and within the scope of these services.

1.4 Reliance

This report has been prepared for the exclusive use of IGET Services LLC and Harris County Flood Control District (HCFCD) and any authorization for use or reliance by any other party (except a governmental entity having jurisdiction over the site) is prohibited without the express written authorization of IGET Services LLC and Terracon. Any unauthorized distribution or reuse is at the client’s sole risk. Notwithstanding the foregoing, reliance by authorized parties will be subject to the terms, conditions and limitations stated in the proposal, LSI report, and Agreement with

January 14, 2022 ■ Terracon Project No. 92207764.T6

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Independent Consultant (Agreement) between iGet Services LLC and Terracon. The limitation of liability defined in the Agreement is the aggregate limit of Terracon’s liability to the client and all relying parties unless otherwise agreed in writing.

2.0 FIELD ACTIVITIES

2.1 Land Clearing

Prior to conducting field activities, land clearing was conducted on the southeastern portion of the site to allow access in the vicinity of the plugged dry hole. Terracon contracted Southeast Texas Trees to conduct the land clearing on November 17, 2021.

2.2 Geophysical Survey

Terracon contracted Earth Measurement Corp. (EMC) to conduct the geophysical survey in an attempt to locate the buried well casing. A geophysical survey crew was deployed to the site on November 19, 2021. The survey included an electromagnetic (EM) survey using a Geometrics G- 858 Cesium Vapor Magnetometer/Gradiometer. Using coordinates obtained from the results of RRC records research, a GPS unit with submeter accuracy was utilized to navigate to the most probable target locations of the wells prior to conducting the geophysical survey.

An anomaly with a high magnetometer reading was detected 112 feet southwest of the target location. The anomaly was “pinpointed” and the backhoe was utilized to investigate each target location. Upon excavation, the anomaly was confirmed to be the well casing. The top of the well casing was buried approximately 3 inches below ground surface (bgs). The coordinates (in decimal degrees) for the location of the verified dry hole well casing are (29.63173996, -

95.09528835) (WGS 1984).

After locating each plugged well, the excavation was backfilled and GPS coordinates for the well were obtained by EMC. In addition, the location of each plugged well was marked with a stake.

A copy of EMC’s geophysical survey report is included in Appendix A. Exhibit 2 is a Site Plan that shows the location of the plugged wells in relation to the pertinent features and site boundaries. Photographs taken during the geophysical survey are presented in Appendix B.

2.2 Soil Borings and Temporary Groundwater Sampling Points

The LSI field activities were conducted on November 23, 2021. Sheraden Porter of Terracon was present during the field activities to direct the work, log the borings, and collect samples. Using the results of the geophysical survey, four shallow soil borings (SB-1 through SB-4) and one deep soil boring (TSP-1) were advanced on-site for the purposes of collecting soil samples for laboratory analysis. The deep soil boring was completed as a temporary groundwater sampling point to facilitate the collection of a groundwater sample. Exhibit 2 is a Site Plan that shows the

January 14, 2022 ■ Terracon Project No. 92207764.T6

Responsive ■ Resourceful ■ Reliable 4 location of the soil borings/temporary groundwater sampling point in relation to the pertinent structures and site boundaries.

The soil borings were drilled by a Monitor Well Driller licensed in the State of Texas to depths of 10 feet bgs for the shallow soil borings and a depth of 25 feet bgs for the deep soil boring using a track-mounted direct push technology (DPT) rig. Sampling equipment was decontaminated by an Alconox wash and potable water rinse prior to commencement of the project and between the installation of each soil boring.

The shallow borings were located approximately 30 feet north (SB-4), east (SB-3), south (SB-2), and west (SB-1) of the located well casing for the dry hole. The deep soil boring (TSP-1) was located in the immediate vicinity of the dry hole.

Soil cores were collected continuously from the surface to the maximum terminal depths of each boring using 5.0-foot-long sampler barrels with acetate liners. The soil cores were examined in the field to document lithology, color, moisture content, and visual or olfactory evidence of impact.

In addition, the samples were scanned with an organic vapor monitor (OVM) equipped with a photoionization detector (PID) to detect the presence of volatile organic vapors. The lithology encountered generally consisted of a silty clay that extends from the near surface to a depth of approximately 20 feet bgs. The silty clay layer was underlain by a layer of clayey sand which extends to the terminal depth of the boring (25 feet bgs). Groundwater was encountered at 21 feet bgs in the deep soil boring (TSP-1). Detailed lithologic descriptions are presented on the soil boring logs included in Appendix C.

At the completion of drilling, the deep soil boring was converted to a temporary groundwater sampling point. The temporary groundwater sampling point consisted of 10 feet of one-inch diameter polyvinyl chloride (PVC) well screen with 0.010-inch slots, a threaded bottom cap, and a sufficient length of one-inch diameter PVC riser pipe to reach the surface.

After installation, the temporary groundwater sampling point was developed by removing groundwater with a peristaltic pump and dedicated plastic tubing until the purge water was relatively free of fine-grained sediment. After the completion of sampling activities, the temporary groundwater sampling point was removed and the borehole abandoned in accordance with applicable regulations.

Following the completion of sampling activities, the TSP was removed, and the boreholes abandoned in accordance with applicable regulations. Purged water recovered from the well during sampling and soil cuttings were dispersed in the vicinity of the respective boreholes.

January 14, 2022 ■ Terracon Project No. 92207764.T6

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2.3 Soil and Groundwater Sampling

The soil sampling program developed by Terracon consisted of collecting soil samples from each boring for laboratory analyses. Soil samples were to be collected from the zone exhibiting the greatest degree of impact based on field screening results. If no evidence of impact was detected by field screening, soil samples were to be collected from an interval selected in the field. Soil sample intervals for each boring are provided on the lithologic boring logs included in Appendix C.

After the temporary groundwater sampling points had been developed, the groundwater level within the temporary groundwater sampling points was allowed to stabilize before a sample was collected using a peristaltic pump and clean, dedicated tubing. One groundwater sample from each temporary groundwater sampling point was also filtered in the field using a 10-micron filter due to potential for suspended sediment to cause false positive results for metals.

Soil and groundwater samples were collected in laboratory prepared glassware or TerraCoreTM sampling kits and placed on ice in a cooler. The samples, along with the completed chain-of-custody forms, were relinquished to Eurofins Xenco Environmental Laboratory in Houston, Texas for analysis. Proper chain of custody documentation was maintained throughout the sampling process. Laboratory QA/QC procedures are included with the laboratory report.

3.0 LABORATORY ANALYTICAL PROGRAM

The analytical program developed by Terracon was based on the potential environmental concerns associated with historic on-site oil/gas E&P activities as well as historic industrial operations conducted throughout the site. Soil and groundwater samples were analyzed for total petroleum hydrocarbons (TPH) by Texas Commission on Environmental Quality (TCEQ) test method TX1005; benzene, toluene, ethylbenzene, xylene (BTEX) by United States Environmental Protection Agency (EPA) test method 8260C; eight-listed Resource Conservation Recovery Act (RCRA 8) metals by EPA test method 6020A/7471B/7470A; and chloride using EPA test method

300. Select soil samples were also analyzed for pH by EPA test method 9045D.

4.0 INVESTIGATION RESULTS AND EVALUATION

Releases of COCs from oil/gas E&P activities are regulated by the RRC. In addition, it is the opinion of Terracon that the site meets the RRC definition of a “sensitive area” based upon the shallow depth to groundwater and the location of the site in proximity to current residential development. The RRC regulates the closure of impacted sites from oil and gas E&P activities in "sensitive areas" using the Texas Risk Reduction Program (TRRP) rules (30 Texas Administrative Code [TAC] 350). Therefore, Terracon compared the concentrations of COCs detected in soil and groundwater at the site to TCEQ Action Levels, which are equivalent to the TRRP Tier 1

January 14, 2022 ■ Terracon Project No. 92207764.T6

Responsive ■ Resourceful ■ Reliable 6 critical protective concentration levels (PCLs) for a residential site with a 0.5-acre source area.

However, for the metals that have higher Texas-Specific Background Concentrations (TSBCs) than their Tier 1 critical PCLs (i.e., arsenic, lead and/or mercury), the TSBC is the Action Level.

The Action Levels for groundwater are equivalent to the TCEQ TRRP Tier 1 PCLs for groundwater ingestion.

Action levels for chloride in soil have not been established under TRRP. According to the RRC draft guidance document “Field Guide for the Assessment and Cleanup of Produced Water Releases” dated December 11, 2009 and the draft “COC Guidelines for Substance Release – Version 12” dated April 13, 2017, soils with maximum chloride concentrations of 3,000 milligrams per kilogram (mg/kg) are generally expected to be protective of groundwater. As such, the RRC has stipulated that chloride concentrations in soil should be laterally and vertically delineated to within 3,000 mg/kg (RRC groundwater protection threshold). Chloride concentrations in groundwater should be delineated to 300 milligrams per liter (mg/L), the Texas Secondary Drinking Water Standard as specified in 30 TAC §290.118(b).

The soil and groundwater sample analytical results have been summarized in Tables 1 and 2, respectively. A copy of the analytical report and chain-of-custody form is included in Appendix D.

4.1 Soil Samples

As discussed above, the soil cores recovered from the borings were screened in the field for evidence of chemical impact such as chemical odors or PID readings. There was no evidence of chemical impact detected in the soil such as odors, staining or PID readings.

· TPH and BTEX constituents were not detected in the soil samples at concentrations above laboratory sample detection limits SDLs.

· RCRA metals were detected in soil samples at concentrations below their TRRP Tier 1 PCLs or TSBCs with the exception of arsenic and lead.

o Arsenic was detected in the soil samples collected from SB-1 (2-4') (10.1 milligrams per kilogram (mg/kg)), SB-2 (2-4’) (6.91 mg/kg), and SB-3 (2-4’) (5.96 mg/kg) at concentrations slightly above the TSBC of 5.9 mg/kg. Therefore, to delineate the vertical extent of arsenic impact to the soil samples, the sample collected from the corresponding deeper interval was submitted for analysis.

Ø Arsenic was detected in the deeper corresponding soil samples at concentrations below the TSBC of 5.9 mg/kg, with the exception of SB-1 (4-6’) (6.36 mg/kg).

o Lead was detected in the soil samples collected from SB-1 (2-4’) (22.2 mg/kg), SB-2 (2-4’) (20.3 mg/kg), and SB-3 (22.1 mg/kg) at concentrations above the TSBC of 15 mg/kg. Therefore, to delineate the vertical extent of lead impact to the soil sample, January 14, 2022 ■ Terracon Project No. 92207764.T6

Responsive ■ Resourceful ■ Reliable 7 the sample collected from the corresponding deeper interval was submitted for analysis.

Ø Lead was detected in the deeper corresponding soil samples at concentrations below the TSBC of 15 mg/kg.

In order to assess if the detected concentrations in soil are protective of groundwater, Terracon calculated a site-specific Tier 2 PCL for arsenic and lead utilizing site-specific data. The TCEQ allows for the calculation of site-specific PCLs using formulas included in the TRRP and site-specific data. The calculated site-specific Tier 2 residential soil-to-groundwater (GWSoilIng) PCL was 20.37 mg/kg for arsenic and 2,882 mg/kg for lead. The detected concentrations of arsenic and lead in on-site soils are below the calculated Tier 2 PCL and also significantly below the residential health-based TotSoilComb PCL of 24 mg/kg and 500 mg/L, respectively. The residential health-based TotSoilComb PCL is developed for protection of individuals who may encounter impacted soil via ingestion, dermal contact, and inhalation of vapors and/or particulate matter. A copy of the Tier 2 PCL calculation is included in Appendix E.

Chloride was detected at concentrations ranging from 42.9 mg/kg to 483 mg/kg, well below the RRC groundwater protection threshold of 3,000 mg/kg.

4.2 Groundwater Samples

· TPH and BTEX constituents were not detected in the groundwater samples at concentrations above laboratory sample detection limits SDLs.

· Metals detected in on-site groundwater were all below their representative TRRP Tier 1 PCLs with the exception of arsenic and lead. However, suspended sediments in the unfiltered samples can result in potential false positive results for metals in turbid samples.

Therefore, due to the potential for suspended sediment to cause elevated metal concentrations in groundwater samples, the filtered samples were also analyzed and the results are discussed below:

o Arsenic was detected in the unfiltered groundwater sample collected from TSP-1 at a concentration of 0.0176 milligrams per liter (mg/L), above the TRRP Tier 1 PCL of 0.01 mg/L. Arsenic was detected at a concentration of 0.000395 mg/L in the filtered groundwater sample, which is below the TRRP Tier 1 PCL.

o Lead was detected in the unfiltered groundwater sample collected from TSP-1 at a concentration of 0.00379 mg/L, above the TRRP Tier 1 PCL of 0.015 mg/L. Lead was detected at a concentration of 0.000177 mg/L in the filtered groundwater sample, which is below the TRRP Tier 1 PCL.

January 14, 2022 ■ Terracon Project No. 92207764.T6

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Ø Analytical results obtained for arsenic and lead from the filtered samples were below the TRRP Tier 1 PCLs, indicating that the PCL exceedances of arsenic and lead in groundwater are apparently due to suspended sediment in the samples.

· Chloride was detected in the groundwater sample collected from TSP-1 at a concentration of 1,050 mg/L, above the Texas Secondary Drinking Water Standard of 300 mg/L that has been adopted by the RRC for aesthetic and ecological assessment.

5.0 FINDINGS AND RECOMMENDATIONS

Based on the results of the investigation, Terracon provides the following findings and recommendations:

■ TPH and BTEX constituents were not detected in the soil or groundwater samples at concentrations above SDLs.

■ Arsenic and lead were detected in the soil samples at concentrations slightly exceeding the Tier 1 PCLs in soil. However, the detected concentrations of arsenic and lead are below the site-specific calculated Tier 2 PCLs.

■ Arsenic and lead were detected in the groundwater samples at concentrations exceeding the Tier 1 PCLs. However, suspended sediments in the unfiltered samples can result in potential false positive results for metals in turbid samples. Therefore, due to the potential for suspended sediment to cause elevated metal concentrations in groundwater samples, the filtered samples were also analyzed. Arsenic and lead were detected in the filtered groundwater samples at concentrations below the Tier 1 PCLs.

■ Groundwater in the vicinity of TSP-1 has been impacted by chloride at concentrations exceeding the Texas Secondary Drinking Water Standard of 300 mg/L that has been adopted by the RRC. Chloride impacts are due to produced water (primarily salt water) which is a byproduct in the production of oil/gas. The secondary drinking water standards are established as guidelines to assist public water systems in managing their drinking water for aesthetic considerations, such as taste, color, and odor.

■ Based on the historical oil/gas operations at the site, petroleum impacted soil or flow lines may be encountered during construction activities, despite the lack of evidence indicating a release during this investigation. Terracon recommends that a Soil and Water Management Plan (S&WMP) be prepared prior to initiation of site redevelopment activities. The objective of the S&WMP would be to provide written direction for construction personnel to follow on how to manage and stage environmentally impacted soil or groundwater encountered at the site for proper characterization and off-site disposal

January 14, 2022 ■ Terracon Project No. 92207764.T6

Responsive ■ Resourceful ■ Reliable 9 in accordance with applicable local, state or federal regulations. Environmentally impacted material should be anticipated to be encountered during site redevelopment activities in the vicinity of the historic oil/gas E&P activities.

■ The well casing associated with the dry hole should be noted during site development activities and if necessary lowered to a depth of at least 3 feet below the construction depth by a specialty oil/gas services contractor.

EXHIBITS

EXHIBIT 1 - SITE VICINITY MAP

EXHIBIT 2 - SITE PLAN

Consulting Engineers and Scientists

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Prepared By: _____________________ Checked By: _____________________

USGS TOPOGRAPHIC QUADRANGLE MAP

La Porte, Texas

Revised: 2019

0 2,0001,000

APPROXIMATE SCALE 1" = 2000'

REW

SJP

Red Bluff Regional Detention Basin System (C-07) HCFCD Project ID# B509-04-00-E001

West Fairmont Parkway and Genoa Red Bluff Road La Porte, Harris County, Texas

TERRACON PROJECT NO. 92207764.6

EXHIBIT 1:

SITE VICINITY MAP

SITE

TEXAS

NOT TO SCALE

N

Undeveloped

Undeveloped

Undeveloped

UndevelopedUndeveloped

Undeveloped

Undeveloped

Pasadean Fire Training

Field

Les Early Firearms Training Center

CG

R ox an e

Commercial BuildingsCommercial Buildings

Coastal Water Authority Bayport Pump Station

B109-00-00

(Spring Gully)

B509-04-00

B509-03-00

B109-00-00

8 9 9

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES

Consulting Engineers and Scientists

Project Mngr:

Drawn By:

Checked By:

Approved By:

Project No.

Scale:

Report:

Date:

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11555 CLAY ROAD, SUITE. 100

PH. (713) 690-8989

HOUSTON, TX 77043

FAX. (713) 690-8787

Site Plan Red Bluff Regional Detention Basin System (C-07)

HCFCD Project ID# B509-04-00-E001 West Fairmont Parkway and Genoa Red Bluff Road

La Porte, Harris County, Texas

EXHIBIT

11-29-2021

1 " = 1,000 '

92207764.6SJP

REW

SJP

GAP

Phase II ESI

Esri, HERE, Garmin, (c) OpenStreetMap contributors, United States Department of Agriculture (USDA). Texas NAIP Imagery, 2020-04-01, Google Earth Aerial Photograph 2020-11-16 Map Presented In: NAD 1983 StatePlane Texas South Central FIPS 4204 Feet

Legend Site Boundary Harris County Parcels HCFCD Waterway High Power Transmission Line Soil Boring Location Temporary Groundwater Sample Point

Oil / Gas Activities

Dry Hole Petroleum Pipeline

0 1,000 2,000500 Feet

1 Sunoco 2 Tracerco 3 Power Core 4 MSA The Safety Company

5 IFI

6 Aztron Chemical Service 7 Harcros 8 Altom Transport, Inc.

9 Torcsill

Surrounding Properties

TSP-1SB-1

SB-2

SB-3

SB-4

Samples Detail 1 " = 50 'Scale:

TABLES

TABLE 1 - SUMMARY OF SOIL ANALYTICAL RESULTS

TABLE 2 - SUMMARY OF GROUNDWATER ANALYTICAL RESULTS

Sample Sample Depth Sample TPH Anions pH

Number (Feet) Date (TCEQ TX 1005) (EPA 300) (EPA 9045D)

C

- C

C ar bo n

R an ge

C

C

C ar bo n R an ge

C

C

C ar bo n R an ge

B en ze ne

T ol ue ne

E th yl be nz en e

X yl en es

A rs en ic

B ar iu m

C ad m iu m

C hr om iu m

L ea d

S el en iu m

S ilv er

M er cu ry

C hl or id e

2-4 <27.3 <27.3 <27.3 <0.000271 <0.00131 <0.000440 <0.00129 10.1 145b <0.136 23.6 22.2b 0.934J <0.186 0.0167J 483 7.0HF

4-6 NA NA NA NA NA NA NA 6.36 NA NA NA 11.8 NA NA NA NA NA

2-4 <26.1 <26.1 <26.1 <0.000260 <0.00126 <0.000422 <0.00124 6.91 170b <0.166 26.8 20.3b 0.965J <0.227 0.0177J 63.1 7.6HF

4-6 NA NA NA NA NA NA NA 2.35J NA NA NA 11.9 NA NA NA NA NA

2-4 <24.3 <24.3 <24.3 <0.000274 <0.00132 <0.000445 <0.00131 5.96 173b <0.144 27.3 22.1b 1.07J <0.197 0.0208J 58.7 7.2HF

4-6 NA NA NA NA NA NA NA 2.48J NA NA NA 7.70 NA NA NA NA NA

SB-4 2-4 11/23/21 <23.9 <23.9 <23.9 <0.000247 <0.00119 <0.000401 <0.00118 3.32J 107b <0.145 17.4 13.1b 0.698J <0.199 0.0166J 65.0 7.7HF

TSP-1 2-4 11/23/21 <25.8 <25.8 <25.8 <0.000214 <0.00103 <0.000347 <0.00102 2.01J 89.3b <0.142 19.3 7.76b <0.609 <0.195 0.0137J 42.9 9.5HF

65 200 200 0.026 8.2 7.6 120 5.9* 440 1.5 2,400 15* 2.3 0.48 0.04* 3,000 (3) -

- - - - - - - 20.37 - - - 2,882 - - - - -

- - - - - - - 24 8,100 52 33,000 500 310 97 3.6 - -

Note: Values shown in bold exceed the TCEQ TRRP 1 PCLs

TPH - total petroleum hydrocarbons BTEX - benzene, toluene, ethylbenzene, xylenes EPA - Environmental Protection Agency TCEQ - Texas Commission on Environmental Quality TRRP - Texas Risk Reduction Program

RRC

PCL - Protective Concentration Level < - not detected at concentrations above the sample detection limits (SDLs) J - The target analyte was positively identified at a concentration between the SDL and the method quantitation limit.

* - Texas Specific Background Concentration (TSBC)

(1) - based on the TRRP critical Tier 1 protective concentration level (PCL) for a residential site with a 0.5-acre source area (2) (3) (4)

(EPA 8260C)

BTEX RCRA Metals

(EPA 6020A/7471B)

TCEQ TRRP Tier 1 PCL (1)

SUMMARY OF SOIL ANALYTICAL RESULTS

11/23/21

SB-3 11/23/21

TABLE 1

- Railroad Commission of Texas all concentrations are in milligrams per kilogram

La Porte, Harris County, Texas West Fairmont Parkway & Genoa Red Bluff Road

HCFCD Project ID B509-04-00-E001

- RRC groundwater protection threshold for chloride in soil (from "Field Guide for the Assessment and Cleanup of Produced Water Releases")

- TRRP Total Soil Combined (TotSoilComb) PCL derived for protection of persons who encounter impacted soil via ingestion, dermal contact, and inhalation of vapors and/or particulate

Red Bluff Regional Detention Basin (C-07)

SB-1 11/23/21

SB-2

TRRP Health-Based PCL (4)

- TRRP Tier 2 PCL calculated using TCEQ equations and site specific pH of the soil sample

TRRP Tier 2 PCL (2)

TABLE 2

SUMMARY OF GROUNDWATER ANALYTICAL RESULTS

all concentrations are in milligrams per liter Sample Sample TPH Chlorides Number Date (TCEQ TX 1005) (EPA 300)

C

- C

C ar bo n R an ge

C

C

C ar bo n R an ge

C

C

C ar bo n R an ge

B en ze ne

T ol ue ne

E th yl be nz en e

X yl en es

A rs en ic

A rs en ic

(F ilt er ed

B ar iu m

C ad m iu m

C hr om iu m

L ea d

L ea d (F ilt er ed

S el en iu m

S ilv er

M er cu ry

TSP-1 11/23/21 <0.786 <0.766 <0.766 <0.000214 <0.000500 <0.000515 <0.000330 0.0176 0.000395 J 0.323 0.000514J 0.0696 0.0379 0.000177 J 0.00206 <0.000251 0.0000390J 1,050

0.98 0.98 0.98 0.005 1 0.7 10 0.01 0.01 2 0.005 0.1 0.015 0.015 0.05 0.12 0.002 300 (2)

EPA

TCEQ

TPH

BTEX

TRRP

RRC

PCL

< - not detected at concentrations above the sample detection limits (SDLs) J - The target analyte was positively identified at a concentration between the SDL and the method quantitation limit

(1) - based on the TRRP critical Tier 1 protective concentration level (PCL) for groundwater ingestion for a residential site

(2) - RRC-adopted Texas Secondary Drinking Water Standard for chloride

- Texas Risk Reduction Program

- Protective Concentration Level

- Railroad Commission of Texas

(EPA 6020A/7470A)

TCEQ TRRP Tier 1 PCL (1)

HCFCD Project ID B509-04-00-E001 Red Bluff Regional Detention Basin (C-07)

West Fairmont Parkway & Genoa Red Bluff Road La Porte, Harris County, Texas

BTEX

(EPA 8260C)

RCRA Metals

- total petroleum hydrocarbons

- benzene, toluene, ethylbenzene, xylenes

- Environmental Protection Agency

- Texas Commission on Environmental Quality

APPENDIX A

GEOPHYSICAL SURVEY REPORT

Houston, TX Office T: 281.829.5700

19 November 2021

Ms. Sheraden Porter Terracon 11555 Clay Road, Ste 100 Houston, Texas 77043

T: 713.939.6473

GEOPHYSICAL INVESTIGATION SURVEY

Harris County Flood Control District Project

B509-04-00-E001 La Porte, Texas

EMC PROJECT#112119

Dear Ms. Porter, The Earth Measurement Corp. (EMC) performed a subsurface investigation survey at your site located at the Harris County Flood Control District Site, located near La Porte, Texas.

The crew utilized a Geonics G-858 Cesium Vapor Magnetometer in an attempt to locate the well head or surface casing of a presumed dry hole. The crew navigated to the Rail Road Commission (RRC) coordinates as a starting point for this survey.

There was a path cleared from the drainage ditch to the west approximately 375 feet. The area is somewhat overgrown but was walkable for the crew and equipment. From the starting point the crew expanded the area surveyed where possible, and was able to locate a target that was consistent with a possible well casing. This target was staked and then excavated to ascertain what was causing the anomalous readings from the magnetometer.

At a depth of approximately 3 inches below ground level the surface casing was exposed.

A GPS point was taken using the Juniper Systems Geode GNSS GPS receiver. The location of the well casing is in the table below. This well casing is approximately 112 feet southwest of the RRC coordinates. Included with this report is a kmz file of the well casing location.

Target Lat Lon

Well Casing 29.63173996 -95.09528835

Please feel free to reach out to EMC if you have any questions or need any additional information.

Best regards, Harold Fulton-Earth Measurement Corp.

APPENDIX B

SITE PHOTOGRAPHS

Project Number 92207764 ■ Limited Site Investigation Date Photos Taken ■ November 17, 19, & 23, 2021

HCFCD Project ID B509-04-00-E001 ■ LaPorte, Texas

Photo 1 View of EMC’s Geophysical

Survey in progress.

Photo 2 Excavation at the location exhibiting strong magnetic anomaly.

Photo 3 Dry hole casing located below ground surface.

Photo 4 Dry hole casing location staked.

Photo 5 Soil borings being advanced by a direct push technology (DPT) drill rig.

Photo 6 Groundwater sampling temporary sampling point TSP-1.

APPENDIX C

BORING LOGS

APPENDIX D

ANALYTICAL LABORATORY REPORTS

ANALYTICAL REPORT

Eurofins Xenco, Stafford 4145 Greenbriar Dr Stafford, TX 77477 Tel: (281)240-4200

Laboratory Job ID: 860-16083-1 Client Project/Site: Red Bluff Regional Detention Basin Sys.

For:

Terracon Consulting Eng & Scientists 11555 Clay Road Suite 100 Houston, Texas 77043

Attn: Sheraden Porter

Authorized for release by:

12/10/2021 5:47:31 PM

Chad Bechtold, Project Manager (813)690-3563 chad.bechtold@eurofinset.com

This report has been electronically signed and authorized by the signatory. Electronic signature is intended to be the legally binding equivalent of a traditionally handwritten signature.

Results relate only to the items tested and the sample(s) as received by the laboratory.

https://secure.testamericainc.com/TotalAccess/login.aspx http://www.testamericainc.com/services-we-offer/ask-the-expert http://www.eurofinsus.com/Env mailto:chad.bechtold@eurofinset.com

Table of Contents

Client: Terracon Consulting Eng & Scientists Project/Site: Red Bluff Regional Detention Basin Sys.

Laboratory Job ID: 860-16083-1

Eurofins Xenco, Stafford

12/10/2021

Cover Page

Table of Contents

Definitions/Glossary

State Forms

DCS Report

TRRP Checklist

Case Narrative

Detection Summary

Client Sample Results

Surrogate Summary

QC Sample Results

QC Association Summary

Lab Chronicle

Certification Summary

Method Summary

Sample Summary

Chain of Custody

Receipt Checklists

Definitions/Glossary Job ID: 860-16083-1Client: Terracon Consulting Eng & Scientists

Project/Site: Red Bluff Regional Detention Basin Sys.

Qualifiers

GC/MS VOA

Qualifier Description

U Analyte was not detected at or above the SDL.

Qualifier

GC Semi VOA Qualifier Description

U Analyte was not detected at or above the SDL.

Qualifier

X Surrogate recovery exceeds control limits

HPLC/IC

Qualifier Description

4 MS, MSD: The analyte present in the original sample is greater than 4 times the matrix spike concentration; therefore, control limits are not applicable.

Qualifier

U Analyte was not detected at or above the SDL.

Metals Qualifier Description

4 MS, MSD: The analyte present in the original sample is greater than 4 times the matrix spike concentration; therefore, control limits are not applicable.

Qualifier b The compound was found in the blank and sample

J Result is less than the MQL but greater than or equal to the SDL and the concentration is an estimated value.

N1 MS, MSD: Spike recovery exceeds upper or lower control limits.

N2 RPD of the MS and MSD exceeds the control limits

U Analyte was not detected at or above the SDL.

General Chemistry Qualifier Description

HF Field parameter with a holding time of 15 minutes. Test performed by laboratory at client's request.

Qualifier

Glossary These commonly used abbreviations may or may not be present in this report.

¤ Listed under the "D" column to designate that the result is reported on a dry weight basis

Abbreviation

%R Percent Recovery

CFL Contains Free Liquid

CFU Colony Forming Unit

CNF Contains No Free Liquid

DER Duplicate Error Ratio (normalized absolute difference)

Dil Fac Dilution Factor

DL Detection Limit (DoD/DOE)

DL, RA, RE, IN Indicates a Dilution, Re-analysis, Re-extraction, or additional Initial metals/anion analysis of the sample

DLC Decision Level Concentration (Radiochemistry)

EDL Estimated Detection Limit (Dioxin)

LOD Limit of Detection (DoD/DOE)

LOQ Limit of Quantitation (DoD/DOE)

MCL EPA recommended "Maximum Contaminant Level"

MDA Minimum Detectable Activity (Radiochemistry)

MDC Minimum Detectable Concentration (Radiochemistry)

MDL Method Detection Limit

ML Minimum Level (Dioxin)

MPN Most Probable Number

MQL Method Quantitation Limit

NC Not Calculated

ND Not Detected at the reporting limit (or MDL or EDL if shown)

NEG Negative / Absent

POS Positive / Present

PQL Practical Quantitation Limit

PRES Presumptive

Eurofins Xenco, Stafford

Page 3 of 60 12/10/2021

Definitions/Glossary

Project/Site: Red Bluff Regional Detention Basin Sys.

Glossary (Continued)

These commonly used abbreviations may or may not be present in this report.

QC Quality Control

Abbreviation

RER Relative Error Ratio (Radiochemistry)

RL Reporting Limit or Requested Limit (Radiochemistry)

RPD Relative Percent Difference, a measure of the relative difference between two points

TEF Toxicity Equivalent Factor (Dioxin)

TEQ Toxicity Equivalent Quotient (Dioxin)

TNTC Too Numerous To Count

Eurofins Xenco, Stafford

Page 4 of 60 12/10/2021

DCS Summary 685986

SoilMatrix: Anions by EPA 300Analytical Method:

Bromide Chloride Fluoride Nitrate as N Nitrite as N Sulfate

Parameter

2.10 1.59 4.72 1.23 1.20 5.72

Spike Amount

2.50 5.00 5.00 1.00 1.00 5.00 mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg

UnitsActual Amount

SDL

0.250 0.354 0.354 0.108

0.0500 2.00

MQL

5.00 10.0 5.00 1.00 1.00 10.0

Prep Method: E300P Laboratory: Xenco - Houston

Page 5 of 60 12/10/2021

DCS Summary 692234

WaterMatrix: Inorganic Anions by EPA 300Analytical Method:

Fluoride Chloride Nitrite as N Sulfate Nitrate as N

Parameter

0.176 0.165

0.0846 0.207

0.0925

Spike Amount

0.100 0.100

0.0500 0.200

0.0500 mg/L mg/L mg/L mg/L mg/L

UnitsActual Amount

SDL

0.0286 0.0738 0.0293

0.109 0.0391

MQL

0.500 0.500 0.100 0.500 0.100

Prep Method: E300P Laboratory: Xenco - Houston

Page 6 of 60 12/10/2021

DCS Summary 692477

SoilMatrix: Total RCRA Metals by SW6020AAnalytical Method:

Antimony Arsenic Barium Beryllium Cadmium Chromium Lead Nickel Selenium Silver

Parameter

0.189 0.284 0.373 0.194 0.155 0.380 0.180 0.167

0.0370 0.167

Spike Amount

0.200 0.400 0.400 0.200 0.200 0.400 0.200 0.200

0.0500 0.200 mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg

UnitsActual Amount

SDL

0.0119 0.0617 0.0347 0.0185 0.0116 0.0271 0.0194 0.0147 0.0496 0.0159

MQL

0.200 0.400 0.400 0.200 0.200 0.400 0.200 0.200 0.200 0.200

Prep Method: SW3051 Laboratory: Xenco - Houston

Page 7 of 60 12/10/2021

DCS Summary 692514

WaterMatrix: Total Metals by SW6020AAnalytical Method:

Antimony Arsenic Beryllium Cadmium Chromium Copper Lead Nickel Selenium Silver Thallium Zinc

Parameter

0.00197 0.00294 0.00191 0.00163 0.00400 0.00242 0.00190 0.00168 0.00237 0.00171

0.000390 0.00312

Spike Amount

0.00200 0.00200 0.00100 0.00100 0.00200 0.00200 0.00100 0.00100 0.00100 0.00100

0.000500 0.00200 mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L

UnitsActual Amount

SDL

0.000240 0.000246 0.000131 0.000147 0.000525 0.000747 0.000152 0.000292 0.000454 0.000251 0.000332 0.000802

MQL

0.00200 0.00400 0.00200 0.00200 0.00400 0.00400 0.00200 0.00200 0.00200 0.00200 0.00200 0.00400

Prep Method: SW3010A Laboratory: Xenco - Houston

Page 8 of 60 12/10/2021

DCS Summary 692514

WaterMatrix: Mercury by SW-846 7470AAnalytical Method:

Mercury

Parameter

0.000110

Spike Amount

0.000100 mg/L

UnitsActual Amount

SDL

0.0000263

MQL

0.000200

Prep Method: SW7470P Laboratory: Xenco - Houston

Page 9 of 60 12/10/2021

DCS Summary 692223

SoilMatrix: Mercury by SW-846 7471BAnalytical Method:

Mercury

Parameter

0.00229

Spike Amount

0.00200 mg/kg

UnitsActual Amount

SDL

0.00384

MQL

0.0200

Prep Method: SW7471P Laboratory: Xenco - Houston

Page 10 of 60 12/10/2021

DCS Summary 692520

SoilMatrix: BTEX-MTBE by SW 8260CAnalytical Method:

MTBE

Benzene Toluene Ethylbenzene m,p-Xylenes o-Xylene

Parameter

0.00123 0.00104 0.00138 0.00115 0.00226 0.00118

Spike Amount

0.00100 0.00100 0.00100 0.00100 0.00200 0.00100 mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg

UnitsActual Amount

SDL

0.000409 0.000207

0.00100 0.000336 0.000800 0.000985

MQL

0.00500 0.00100 0.00500 0.00100 0.00200 0.00100

Prep Method: SW5035A Laboratory: Xenco - Houston

Page 11 of 60 12/10/2021

DCS Summary 692369

WaterMatrix: BTEX-MTBE by SW 8260CAnalytical Method:

MTBE

Benzene Toluene Ethylbenzene m,p-Xylenes o-Xylene

Parameter

0.000750 0.000370 0.000480 0.000260 0.000900 0.000430

Spike Amount

0.000500 0.000250 0.000500 0.000250

0.00100 0.000500 mg/L mg/L mg/L mg/L mg/L mg/L

UnitsActual Amount

SDL

0.000571 0.000214 0.000500 0.000146 0.000330 0.000192

MQL

0.00500 0.00100 0.00100 0.00100

0.0100 0.00100

Prep Method: SW5030B Laboratory: Xenco - Houston

Page 12 of 60 12/10/2021

DCS Summary 692520

SoilMatrix: TPH by Texas1005Analytical Method:

C6-C12 Gasoline Range >C12-C28 Diesel Range

Parameter

25.0 21.0

Spike Amount

25.0 25.0 mg/kg mg/kg

UnitsActual Amount

SDL

21.1 21.1

MQL

50.0 50.0

Prep Method: TX1005P Laboratory: Xenco - Houston

Page 13 of 60 12/10/2021

DCS Summary 692348

WaterMatrix: TPH by Texas1005Analytical Method:

C6-C12 Gasoline Range >C12-C28 Diesel Range

Parameter

0.220 0.210

Spike Amount

0.250 0.250 mg/L mg/L

UnitsActual Amount

SDL

0.885 0.863

MQL

5.00 5.00

Prep Method: TX1005P Laboratory: Xenco - Houston

Page 14 of 60 12/10/2021

Appendix A

Laboratory Data Package Cover Page - Page 1 of 4

This data package is for Job No. 860-16083-1 and consists of:

This signature page, the laboratory review checklist, and the following reportable data:

R1- Field chain-of-custody documentation;þ

R2 - Sample identification cross-reference;þ

R3 - Test reports (analytical data sheets) for each environmental sample that includes:

a. Items consistent with NELAC Chapter 5,

b. dilution factors,

c. prepatation methods,

d. cleanup methods, and

e. if required for the project, tentatively identified coumpounds (TICs).

þ

R4 - Surrogate recovery data including:

a. Calculated recovery (%R), and

b. The laboratory’s surrogate QC limits.

þ

R5 - Test reports/summary forms for blank samples;þ

R6 - Test reports/summary forms for laboratory control samples (LCSs) including:

a. LCS spiking amounts,

b. Calculated %R for each analyte, and

c. The laboratory’s LCS QC limits.

þ

R7 - Test reports for project matrix spike/matrix spike duplicates (MS/MSDs) including:

a. Samples associated with the MS/MSD clearly identified,

b. MS/MSD spiking amounts,

c. Concentration of each MS/MSD analyte measured in the parent and spiked samples,

d. Calculated %Rs and relative percent differences (RPDs), and

e. The laboratory’s MS/MSD QC limits þ

R8 - Laboratory analytical duplicate (if applicable) recovery and precision:

a. The amount of analyte measured in the duplicate,

b. The calculated RPD, and

c. The laboratory’s QC limits for analytical duplicates.

þ

R9 - List of method quantitation limits (MQLs) and detectability check sample results for each analyte for each method and matrix;

þ

R10 - Other problems or anomalies.þ

Exception Report for every "No" or "Not Reviewed (NR)" item in Laboratory Review Checklist and for each analyte, matrix, and method for which the laboratory does not hold NELAC accreditation under the Texas Laboratory Accreditation Program.

Release Statement: I am responsible for the release of this laboratory data package. This laboratory is NELAC accredited under the Texas Laboratory Accreditation Program for all the methods, analytes, and matrices reported in this data package except as noted in the Exception Reports. The data have been reviewed and are technically compliant with the requirements of the methods used, except where noted by the laboratory in the Exception Reports. By my signature below, I affirm to the best of my knowledge all problems/anomalies observed by the laboratory have been identified in the Laboratory Review Checklist, and no information affecting the quality of the data has been knowingly withheld.

Check, if applicable: ¨ This laboratory meets an exception under 30 TAC §25.6 and was last inspected by ¨ TCEQ or ¨ ______ on __/__/__. Any findings affecting the data in this laboratory data package are noted in the Exception Reports herein. The official signing the cover page of the report in which these data are used is responsible for releasing this data package and is by signature affirming the above release statement is true.

Name (Printed) Signature Official Title (Printed) Date

Chad Bechtold Project Manager 12/10/2021

Page 15 of 60 12/10/2021

Laboratory Data Package Cover Page - Page 2 of 4

Laboratory Name: LRC Date:

Project Name:

Reviewer Name:

Laboratory Job Number:Red Bluff Regional Detention Basin Sys. 860-16083-1 12/10/2021Eurofins Xenco, Stafford

#¹ A² Description Yes No NA³ NR⁴ ER#⁵ OI Chain-of-custody (C-O-C)R1

Did samples meet the laboratory’s standard conditions of sample acceptability upon receipt?

ü

Were all departures from standard conditions described in an exception report? ü

OI Sample and quality control (QC) identificationR2 Are all field sample ID numbers cross-referenced to the laboratory ID numbers? ü

Are all laboratory ID numbers cross-referenced to the corresponding QC data? ü

OI Test reportsR3 Were all samples prepared and analyzed within holding times? ü

Other than those results < MQL, were all other raw values bracketed by calibration standards?

ü

Were calculations checked by a peer or supervisor? ü

Were all analyte identifications checked by a peer or supervisor? ü

Were sample detection limits reported for all analytes not detected? ü

Were all results for soil and sediment samples reported on a dry weight basis? ü

Were % moisture (or solids) reported for all soil and sediment samples? ü

Were bulk soils/solids samples for volatile analysis extracted with methanol per

SW846 Method 5035?

ü

If required for the project, are TICs reported? ü

O Surrogate recovery dataR4 Were surrogates added prior to extraction? ü

Were surrogate percent recoveries in all samples within the laboratory QC limits? 1ü

OI Test reports/summary forms for blank samplesR5 Were appropriate type(s) of blanks analyzed? ü

Were blanks analyzed at the appropriate frequency? ü

Were method blanks taken through the entire analytical process, including preparation and, if applicable, cleanup procedures?

ü

Were blank concentrations < MQL? 2ü

OI Laboratory control samples (LCS):R6 Were all COCs included in the LCS? ü

Was each LCS taken through the entire analytical procedure, including prep and cleanup steps?

ü

Were LCSs analyzed at the required frequency? ü

Were LCS (and LCSD, if applicable) %Rs within the laboratory QC limits? ü

Does the detectability check sample data document the laboratory’s capability to detect the COCs at the MDL used to calculate the SDLs?

ü

Was the LCSD RPD within QC limits? ü

OI Matrix spike (MS) and matrix spike duplicate (MSD) dataR7 Were the project/method specified analytes included in the MS and MSD? ü

Were MS/MSD analyzed at the appropriate frequency? ü

Were MS (and MSD, if applicable) %Rs within the laboratory QC limits? 3ü

Were MS/MSD RPDs within laboratory QC limits? ü

OI Analytical duplicate dataR8 Were appropriate analytical duplicates analyzed for each matrix? ü

Were analytical duplicates analyzed at the appropriate frequency? ü

Were RPDs or relative standard deviations within the laboratory QC limits? ü

OI Method quantitation limits (MQLs):R9 Are the MQLs for each method analyte included in the laboratory data package? ü

Do the MQLs correspond to the concentration of the lowest non-zero calibration standard?

ü

Are unadjusted MQLs and DCSs included in the laboratory data package? ü

OI Other problems/anomaliesR10 Are all known problems/anomalies/special conditions noted in this LRC and ER? ü

Was applicable and available technology used to lower the SDL to minimize the matrix interference effects on the sample results?

4ü

Is the laboratory NELAC-accredited under the Texas Laboratory Accreditation Program for the analytes, matrices and methods associated with this laboratory data package?

ü

Page 16 of 60 12/10/2021

Laboratory Data Package Cover Page - Page 3 of 4

Project Name:

Reviewer Name:

Laboratory Job Number:Red Bluff Regional Detention Basin Sys. 860-16083-1 12/10/2021Eurofins Xenco, Stafford

#¹ A² Description Yes No NA³ NR⁴ ER#⁵ OI Initial calibration (ICAL)S1

Were response factors and/or relative response factors for each analyte within QC limits?

ü

Were percent RSDs or correlation coefficient criteria met? ü

Was the number of standards recommended in the method used for all analytes? ü

Were all points generated between the lowest and highest standard used to calculate the curve?

ü

Are ICAL data available for all instruments used? ü

Has the initial calibration curve been verified using an appropriate second source standard?

ü

OI Initial and continuing calibration verification (ICCV and CCV) and continuing calibration blank (CCB):

S2

Was the CCV analyzed at the method-required frequency? ü

Were percent differences for each analyte within the method-required QC limits? 5ü

Was the ICAL curve verified for each analyte? ü

Was the absolute value of the analyte concentration in the inorganic CCB < MDL? ü

O Mass spectral tuningS3 Was the appropriate compound for the method used for tuning? ü

Were ion abundance data within the method-required QC limits? ü

O Internal standards (IS)S4 Were IS area counts and retention times within the method-required QC limits? ü

OI Raw data (NELAC Section 5.5.10)S5 Were the raw data (for example, chromatograms, spectral data) reviewed by an analyst?

ü

Were data associated with manual integrations flagged on the raw data? ü

O Dual column confirmationS6 Did dual column confirmation results meet the method-required QC? ü

O Tentatively identified compounds (TICs)S7 If TICs were requested, were the mass spectra and TIC data subject to appropriate checks?

ü

I Interference Check Sample (ICS) resultsS8 Were percent recoveries within method QC limits? ü

I Serial dilutions, post digestion spikes, and method of standard additions

S9

Were percent differences, recoveries, and the linearity within the QC limits specified in the method?

ü

OI Method detection limit (MDL) studiesS10 Was a MDL study performed for each reported analyte? ü

Is the MDL either adjusted or supported by the analysis of DCSs? ü

OI Proficiency test reportsS11 Was the laboratory's performance acceptable on the applicable proficiency tests or evaluation studies?

ü

OI Standards documentationS12 Are…