Bryan W. Shaw, Ph.D., P.E., Chairman

Toby Baker, Commissioner

Jon Niermann, Commissioner

Richard A. Hyde, P.E., Execulive Director

TEXAS COMMISSION ON ENVIRONMENTAL QUALITY

Protecting Texas by Reducing and Preventing Pollution

June 16, 2017

Mr. Tony Saturni, Corporate Remediation Manager CES Griggs Road PRP Group 2 9400 Lakeland Boulevard Wickliffe, Ohio 44092

Re: CES Griggs Road Site, 4900 Griggs Road, 4904 Griggs Road and 5910 Wayland Street, Houston, Harris County, Texas; Voluntary Cleanup Program (VCP) No. 2751; Customer No. CN604824904; Regulated Entity No. RN1083 70644

Dear Mr. Saturni:

The Texas Commission on Environmental Quality (TCEQ) has reviewed the April 18, 2017 report entitled "Revised Affected Property Assessment Report (AP AR) with Response to June and November 2016 Comments on APAR" and the May 10, 2017 submittal entitled "TRRP 350.55 Notification", prepared by Pastor, Behling & Wheeler LLC. Unless otherwise specifically requested, please provide an APAR addendum addressing the following comments.

Comments for "Revised Affected Property Assessment Report (AP AR) with Response to June and November 2016 Comments on APAR"

1. Representative concentrations - The APAR revision documents the appropriateness of the statistical tests as required by 30 TAC 350.79(2)(A); describing the bias in the data set used in the calculations to show that the representative concentrations were not biased low; and explaining the relationship between the affected soil depth and the depth to groundwater in relation to manganese. However, the TCEQ does not concur that the samples used in the representative concentration derivation was confined to samples collected from the appropriate exposure area for the site.

Specifically, Figures llA-1 through llA-3 outlined the 0.5-acre exposure areas used for calculating the representative concentrations for comparison to the critical PCLs. The exposure areas also included off-site property (right-of-way east of 5910 Wayland). Off­site samples were included in the representative soil calculations for manganese and vanadium. Inclusion of this off-site property in calculating the representative concentrations is not appropriate.

Representative concentrations for vanadium (420 mg/kg), were calculated using off-site samples not representative of on-site conditions. Please recalculate the representative concentrations for the 5910 Wayland property without including the samples collected from off-site and compare the results to the applicable T

0 'Soilcomb PCL. Additionally, please include the T

0 'Soilcomb PCL exceedances identified on the off-site property in your PCL exceedance zone maps.

2. Manganese in surface soil - Maps provided with the APAR indicate that soil samples 5910-SB05, and 5910-SBlS were collected from property not owned or controlled by the applicant. As such, the results from these samples should be compared to the

P.O. Box 13087 • Austin, Texas 78711·3087 • 512-239-1000 • tceq.texas.gov

How is our customer service? tceq.texas.gov/customersurvey

printed on recyclerj p~per using ve<;ietable-based ink

Mr. Tony Saturni Page 2 June 16, 2017 VCP No. 2751

residential T0 'Soilcomb PCL, rather than the commercial/industrial T0 'Soilcomb PCL as was

done in Section 11.3 of the APAR. Please update Section 11.3 and correct figure llA.l to show the manganese surface soil PCLE zone for this portion of the site.

3. Groundwater gradient information - The TCEQ notes that the groundwater gradient at the CES site is identified in a northerly direction north of MW-07 and a south­southeasterly direction south of MW-07. The northerly groundwater gradient is consistent to gradient information for leaking petroleum storage tanks (LPST) site No. 119722, which is a Shell gas station across Griggs Road and northeast of CES. The south-southeasterly groundwater gradient appears to mimic gradient information for LPST No. 118348, which is a MLK C-Store located east of CES. Please note the south­southeasterly groundwater gradient identified on the southern portion of the site conflicts with groundwater gradient information for VCP No. 2729 (Former Joy Tabernacle Church Property), located immediately east of CES. Groundwater gradient maps for VCP No. 2729 identify a southwest groundwater gradient (utilizing VCP No. 2729 MW-3 as a reference point).

Given the groundwater gradient discrepancies, close proximity of the VCP sites to one another, and the similar constituents of concern in groundwater; monitor wells on both sites should be surveyed relative to a common benchmark and gauged and sampled at the same time. Once the data is obtained, maps depicting the groundwater gradient and iso-concentration maps should be submitted for TCEQ review, along with the data and groundwater elevation and analytical summary tables for all the wells.

4. Additional groundwater assessment - The APAR revision notes that three newly installed monitor wells (MW-06 through MW-08) were advanced at the site to collect additional groundwater data for site characterization and delineation purposes. Samples collected from MW-06 exhibited exceedances of the residential assessment level (RAL) for trichloroethene (TCE) (0.0061 mg/L & 0.0063 mg/L) and vinyl chloride (0.0037 mg/L & 0.0051 mg/L).

The revised APAR identifies off-site MW-10, associated with VCP No. 2729 (Former Joy Tabernacle Church Property), as a delineation well. However, the groundwater gradient at MW-06 has a south-southeasterly direction and MW-10 (VCP 2 72 9) is located approximately 120' east of MW-06 (not immediately down gradient of MW-06). Please note, off-site MW-3 (also associated to VCP No. 2729) is located approximately 250' southeast of MW-06. Groundwater samples analyzed from MW-3 (VCP 2729) have had exceedances of the RAL for cis-1,2-dichloroethene (cis-DCE), tetrachloroethene (PCE), and TCE. These same COCs have been identified in the CES groundwater sample location. Installation of additional well(s) may be needed to delineate groundwater contamination pending completion of the requested actions in Comment No. 3 (regarding identification of the groundwater gradient). As delineation continues please make appropriate notifications, as needed, as required by 30 TAC 350.55.

In addition, the TCEQ understands that cone penetrometer tests (CPT) were conducted to identify the presence of a laterally continuous clay layer that could possibly separate the upper groundwater bearing unit (GWBU) from a second sand unit. The TCEQ notes that data located in the boring logs for the CPT test do not indicate a continuous clay layer. The 20' thick clay layer identified contains intermittent sands and clayey sands

Mr. Tony Saturni Page 3 June 16, 2017 VCP No. 2751

which may allow for vertical migration of contamination and connection of the first and second sands. Additional assessment of this second sand (approximately 40-60' bgs) should be conducted to determine whether the contamination identified in the shallow sand is also present in the second sand.

5. Expanded list of analytes in groundwater - The TCEQ stated in a November 30, 2016 letter that additional groundwater samples were needed for volatile organic compounds (VOCs), and semi-volatile organic compounds (SVOCs). The APAR revision states that groundwater was sampled for: chlorinated volatile organic compounds (CVOCs) consisting of cis-DCE, PCE, trans-1,2-dichloroethene, TCE, and vinyl chloride; SVOCs consisting of 1-methylnaphthalene (the only SVOC); TPH; and metals consisting of barium, manganese, and vanadium. The TCEQ does not concur that all potential COCs in groundwater have been evaluated and therefore requests additional groundwater samples be collected and analyzed for the entire suite of voes and SVOCs.

6. Request for no further action for TPH - The APAR revision notes that TPH (CG-Ci2) at boring location 4904-SBl 5 (0-2 feet) exceeds the critical protective concentration level (cPCL) of 650 mg/kg with a detection of 1600 mg/kg. TPH at this location is not protective of human health thus the TCEQ does not concur that no further action is needed. Please identify how TPH will be rendered protective in a future Response Action Plan submittal.

Please submit an APAR Addendum to the TCEQ at the letterhead address using mail code MC-221within120 days of the date of this letter. Please provide two copies of your submittals, preferably one electronic (on disk or USB drive) and one hard copy. Should you need additional information or wish to discuss these comments or due date, please call me at (512) 239-2205.

Sincerely,

~~ Rodney Bryant, Project Manager VCP-CA Section Remediation Division Texas Commission on Environmental Quality

RB/jdm

cc: Ms. Brenda Basile, Ph.D., Pastor, Behling, & Wheeler, LLC, 11231 Richmond Avenue, Dl04, Houston, Texas 77082

Mr. Jason Ybarra, Waste Section Manager, TCEQ Houston Region Office, R-12