Raba Kistner Environmental, Inc. 12821 W. Golden Lane San Antonio, TX 78249
P.O. Box 690287 San Antonio, TX 78269-0287
P 210 :: 699 :: 9090 F 210 :: 699 :: 6426 TBPE Firm F-3257
San Antonio Austin Brownsville Corpus Christi Dallas El Paso Houston McAllen Mexico Salt Lake City
Project No. ASA12-126-07 November 12, 2013 Mr. Jeff L. Haberstroh Project Director Henry B. Gonzalez Convention Center Expansion Project Project Control of Texas, Inc. 17300 Henderson Pass, Suite 110 San Antonio, Texas 78232 RE: Baseline Environmental Assessment
Henry B. Gonzalez Convention Center Expansion Project Area No. 3 San Antonio, Bexar County, Texas
Dear Mr. Haberstroh: Raba Kistner Environmental, Inc. (RKEI) is pleased to submit this Baseline Environmental Assessment (BEA) Report to Project Control of Texas, Inc. (CLIENT) on behalf of City of San Antonio Capital Improvement Management Services (CIMS) that provides an evaluation of environmental conditions for soils to be excavated from the eastern expansion area of the Henry B. Gonzalez Convention Center (HBGCC) located in downtown San Antonio, Texas. The overall Henry B. Gonzales Expansion Project (HBGEP) has been divided into three zones designated Areas 1, 2 and 3 during previous phases of environmental assessment conducted by Geo Strata Environmental Consultants, Inc. (Geo Strata) on behalf of Hunt-Zachry (H-Z), the joint venture design-build contractor for the HBGEP. The subsurface investigation recently conducted by RKEI and reported herein involved supplemental environmental assessment activities in Area 3 only, which is located east of the Grand Hyatt Expansion of the existing HBGCC and includes portions of E. Market St., S. Bowie St., Hemisfair Memorial Garden, the Alamodome pedestrian walkway and the former San Antonio Water System (SAWS) headquarters building. The aerial extent of HGBEP Area 3 (hereinafter referred to as the SITE) is depicted on Figure 1 Site Location Map. As discussed herein, subsurface investigation activities were performed in accordance with the scope of services defined in RKEI Proposal No. PSF13-319-00 (Revised), dated October 15, 2013. This report was prepared for Project Control of Texas, Inc. on behalf of CIMS for the stated purpose and may not contain sufficient information for other parties or other purposes. If other parties wish to rely on this report, they should contact RKEI such that a mutual understanding and agreement of the terms and conditions for our services can be established prior to the use of information contained in this report. BACKGROUND In accordance with CLIENTs prior request, RKEI reviewed the Phase I Environmental Site Assessment Report (ESA-I Report), dated January 2013, prepared by Geo Strata for H-Z, which presented assessment findings and recommendations for areas assessed within and immediately surrounding the planned HBGEP area. The desktop review was performed to identify salient ESA-I findings, particularly the existence of recognized environmental conditions (RECs) that could potentially impact demolition and/or construction activities associated with the planned HBGEP improvement project. Based on the
Project No. ASA12-126-07 November 12, 2013
referenced ESA-I Report review findings, RKEI offered, among others, the following recommendations in support of HBGEP planning efforts (i.e., RKEI Project No. ASA12-126-01, report dated March 20, 2013):
H-Z should consider procurement and review of the Phase II ESA report referenced in the Geo-Strata ESA-I Report for the Hemisfair area filed with the City of San Antonio (COSA) Attorneys office to identify previously affected environmental media areas/extents within HBGEP Area 3;
Following review and evaluation of any additional information, H-Z should consider securing a qualified environmental services provider to conduct an intrusive subsurface investigation to evaluate the presence of impacts associated with past land use activities in HBGEP areas identified as RECs in the ESA-I Report, and to establish baseline environmental conditions for these planned project demolition and/or construction areas; and
If the presence of residual environmental media impacts is demonstrated as a result of focused ESA-II activities, H-Z should consider appropriate soil and/or groundwater management planning to facilitate a real-time soil screening and segregation process for on/offsite reuse evaluation and to address potentially affected media handling and disposal means and methods and worker health and safety considerations during planned future HBGEP earthwork activities.
Geo Strata subsequently conducted a Phase II Environmental Site Assessment (ESA-II) in mid-July 2013, consisting of subsurface investigation activities throughout the HBGEP and collection of environmental media (i.e., soil and shallow groundwater) samples for chemical testing. In accordance with CLIENTs request, RKEI reviewed the Geo Strata (August 2013) ESA-II Report and addendum for the purpose of interpreting salient subsurface investigation findings within the context of applicable Texas Commission on Environmental Quality (TCEQ) Tier 1 Protective Concentration Levels (PCLs). Generally speaking, PCLs are defined pursuant to Texas Risk Reduction Program (TRRP) rules (i.e., Title 30 Texas Administrative Code, Chapter 350, Subchapter D, 350.75) and are screening standards representing the maximum concentrations of chemicals of concern (COCs) that can be present in environmental media (i.e., soil and groundwater) that are considered protective of human health in a residential land use setting, in addition to groundwater resources. With respect to common heavy metals contaminants (i.e., RCRA 8 metals), many of which are naturally-occurring throughout the State of Texas, measured concentrations were also compared to respective Texas Specific Background (TSB) values, which are median background concentrations of naturally occurring metals defined by TCEQ for Texas. TSB values, when greater than Tier 1 PCLs, are utilized for evaluation of potential heavy metals impact to soils. The following is a summary of salient environmental findings pertaining to HBGEP Area 3 based on RKEIs review of the final Geo Strata ESA-II and Addendum reports (dated August and September 2013, respectively). For the purposes of the following discussion, the locations of referenced environmental soil borings are depicted on Figure 2 Sampling Grid Location Map. Corresponding analytical sampling data generated by Geo Strata for Area 3 is provided on Figures 3 and 4 Summary of Analytical Results for Soil and Groundwater.
Analytical results indicated no total petroleum hydrocarbon (TPH), volatile organic compound (VOC) or Resource Conservation and Recovery Act (RCRA) 8 metal impacts to shallow groundwater encountered to depths of 30 feet below ground surface (bgs) within unconsolidated native soils and/or historically emplaced fill soils overlying the Navarro Clay formation (a confining unit separating surface soils from the underlying Edwards Aquifer further discussed later in this report), within Geo Strata designated HBGEP Area 3.
Project No. ASA12-126-07 November 12, 2013
Analytical results indicated no TPH or VOC impacts to near-surface native clay soil, silty/sandy (disturbed) or emplaced fill soils, or underlying (undisturbed) Navaro Clay sampled throughout HBGEP Area 3 that could be attributable to past land use activities or historical placement(s) of contaminated fill soils.
RCRA 8 metals arsenic, barium, lead, mercury and selenium were detected at varying depths in native, disturbed transitional, and historically emplaced fill soils at various HBGEP locations at concentrations exceeding applicable groundwater protection screening levels (i.e., their TSBs).
Arsenic concentrations exceeding the TSB were reported at select locations in HGBEP were isolated and spatially dispersed throughout Area 3. Additional leachability testing by the Synthetic Process Leaching Procedure (SPLP) method conducted on the sample exhibiting a maximum arsenic value of 19.1 mg/kg (i.e., SB-12g, 17.5-20 ft bgs) indicated a result below the applicable TRRP Tier 1 groundwater protection PCL, indicating that the maximum reported arsenic concentration is protective of shallow groundwater.
Selenium concentrations exceeding the TSB were reported as being widely dispersed throughout soil boring locations and soil sample depths within borings. SPLP analysis results conducted on the on the sample exhibiting a maximum selenium value of 8.25 mg/kg (i.e., SB-12f, 2-5 ft bgs) indicated a result below the applicable TRRP Tier 1 groundwater protection PCL, indicating that the maximum reported selenium concentration is protective of shallow groundwater.
Mercury concentrations exceeding the TSB were also reported as being widely dispersed throughout soil boring locations and soil sample depths within borings. Although SPLP testing was not conducted in Area 3, results of SPLP testing on the sample collected from Area 1 exhibiting a maximum mercury value of 0.292 mg/kg (i.e., SB-34, 0-5 ft bgs) indicated a result below the applicable TRRP Tier 1 groundwater protection PCL, indicating that the maximum reported mercury concentration is protective of shallow groundwater.
Lead concentrations exceeding the TSB were also reported throughout Area 3 as spatially dispersed. Maximum lead concentrations in near-surface soils were reported in Area 1 borings SB-33 (156 mg/kg) and SB-39a (144 mg/kg) at levels greater than 100 mg/kg. The SPLP analysis result for soil samples collected at SB-39a (4-7.5 ft) and SB-33 (2-5 ft) indicated an exceedance of the TRRP Tier 1 groundwa