Two (2) groundwater plumes consisting of chlorinated solvents (1,1-dichloroethene and vinyl chloride) were detected at a chemical plant site. One (1) plume was detected through a Phase II Environmental Site Assessment conducted for due diligence purposes in association with an industrial real estate transaction, and the other plume was detected during a RCRA Facility Investigation (RFI) conducted for permit compliance purposes. The assessments identified two (2) distinct groundwater PCLE zones that were confined to the site, and long-term monitoring data supported the use of MNA to address the contamination within the context of plume management zones (PMZs) under the TRRP.
Conducted field work during assessment phase, including soil and groundwater sampling, drilling oversight and soil logging, soil boring and monitor well installation, well development and sampling. Coordinated and directed drilling, field sampling, surveying, and laboratory services. Supervised data reduction efforts including development of spreadsheets and graphs to track changes in contaminant concentration versus time, figures, tables, etc., as necessary to present our findings. Data interpretation and reporting, including preparation of Affected Property Assessment Report (APAR), Response Action Plan (RAP), Response Action Effectiveness Reports (RAERs), and Response Action Completion Reports (RACRs).
RCRA Facility Investigation, Baseline Risk Assessment (BLRA), Corrective Measures Study (CMS) and Corrective Measures Implementation
1) RFI - determine the nature, degree and extent of soil and groundwater contamination released from nine (9) solid waste management units (SWMUs) at a chemical plant as required by the plant=s RCRA Permit. 2). BLRA - determine risks to human health and the environment posed by contamination emanating from the site under current and potential future land uses, assuming no remedial action. 3). CMS - select the most cost-effective remedial option for areas of concern that were determined to require cleanup under the BLRA (i.e., perform an engineering feasibility study). 4). CMI – design, construct, operate, maintain, and monitor the corrective measures (clean-up activities) recommended in the CMS report.
RFI - Reviewed the Phase I RFI Report and prepared a comment and response document for submittal to the TNRCC concerning the Phase I Report. Negotiated the scope of work for Phase II investigation with regulatory personnel. Designed groundwater and soil investigation program and submitted Phase II RFI workplan for regulatory approval. Supervised and implemented field investigation including management of subcontractors, monitor well installation, drilling of soil borings, and soil and groundwater sample collection. Data reduction and evaluation including construction of relational database, use of statistics for data evaluation, preparation of soil boring logs, geologic cross-sections, and potentiometric surface elevation contour maps. Prepared Phase II RFI report. Responsibilities:
BLRA - Selected chemicals of potential concern (COPCs), developed a conceptual exposure pathways model, performed toxicity assessment for COPCs, and prepared a characterization of risk to human health and the environment. Developed cleanup levels in the source area based on toxokinetics and in downgradient areas using groundwater modeling (with and without biodegradation) through estimatation of future contaminant loadings on identified receptors. Utilized bioparameters testing to evaluate the bioassimilative capacity of the contaminated aquifer (i.e., quantify the potential for the aquifer to clean itself using naturally occurring microbes).
CMS - Evaluated various remedial options to address contamination and recommended groundwater pump and treat system as a presumptive remedy. Utilized groundwater modeling to develop conceptual design for system of groundwater extraction wells to meet the following three objectives: 1). Capture contaminated groundwater along and to the south of facility property line; 2). Prevent further migration of contaminants; and 3). Utilize natural attenuation processes such as in-situ biodegradation, retardation and dilution to reduce current contaminant concentrations in downgradient areas outside the anticipated capture zone.
Also, developed a sampling and analysis plan for long-term groundwater monitoring to be required for post-closure care; prepared a cost estimate and schedule for implementation of proposed corrective measures, and developed Compliance Plan Application for submittal to TCEQ.
Affected Property Assessment and MNA Demonstration
Affected soil and groundwater were detected during an RFI conducted at an inactive surface impoundment that spanned a 110 acre tract on a RCRA permitted facility. The assessment several distinct soil and/or groundwater PCLE zones that were confined to the site, and long-term monitoring was conducted to evaluate the effectiveness of MNA as a response action to achieve closure under TRRP Remedy Standard B.
Conducted field work during assessment phase, including soil and groundwater sampling, drilling oversight and soil logging, soil boring and monitor well installation, well development and sampling. Coordinated and directed drilling, field sampling, surveying, and laboratory services. Supervised data reduction efforts including development of spreadsheets and graphs to track changes in contaminant concentration versus time, figures, tables, etc., as necessary to present our findings. Data interpretation and reporting, including preparation of Affected Property Assessment Report (APAR).
To raise the groundwater protection standard (i.e., cleanup level) for a release from a hazardous waste management unit (HWMU) undergoing remediation, based on an evaluation of potential risk to human health and the environment.
Assembled site-specific data on the nature and extent of contamination, hydrogeologic conditions, and potential exposure pathways. Utilized groundwater modeling to evaluate contaminant fate and transport processes at the site. Prepared a risk assessment to evaluate potential impacts to human health and the environment posed by site groundwater contamination to determine if alternate (i.e., higher) concentrations of selected contaminants would remain protective of potentially exposed receptors. Negotiated clean-up standards with regulatory agency personnel.
To certify clean closure of an emergency use surface impoundment following clean-up actions taken in response to a release of hazardous waste. .
Prepared a closure plan in accordance with 40 CFR Part 265. Sampled pond sediment, pond water and groundwater. Prepared a Closure Certification Report to demonstrate that no hazardous waste remained after performance of emergency rectification procedure.
To re-classify the regulatory status of approximately 36 hazardous waste management tanks.Responsibilities:
Provided permitting assistance. Negotiated with regulatory personnel to obtain approval for hazardous waste permitting exclusions based upon the Accumulation Time exemption and the exemption for Totally Enclosed Treatment Facilities. Trained plant ESHA coordinators regarding compliance with exclusion requirements.
To evaluate long-term waste containment and relative degree of environmental protection for an onsite Class I non-hazardous landfill.Responsibilities:
Obtained soil samples for geotechnical analysis. Evaluated current landfill design and management practices, and compare to technical guidelines recommended by the Texas Natural Resource Conservation Commission. Utilized EPA=s Hydrologic Evaluation of Landfill Performance Model to simulate leachate production and potential impacts to groundwater beneath the site. Recommended improvements in landfill design and operation.
This is an ongoing project to assist with collecting, interpreting and reporting site-specific hydrogeologic data to comply with the post-closure care requirements of a chemical plant=s RCRA Permit and Compliance Plan. Project involves implementation of the Corrective Action Monitoring Program per requirements of the facility’s Compliance Plan.Responsibilities:
Groundwater sampling; data reduction and statistical analysis of laboratory results. Preparation of potentiometric surface elevation contour maps. Determination of groundwater flow rate and direction. Design and install a groundwater recovery system. Conducted inspections and performed operations and maintenance activities for groundwater monitoring and recovery systems.