Environmental Services from Terrane
When are Environmental Services Needed?
As with geotechnical services, environmental services may be required during any phase of a project or development, and the nature of services required will vary according to the project phase, scale, and type. From a development perspective there are two types of environmental studies: (1) those aimed at natural and historic characteristics of a site such as archaeology flora, fauna, habitat, and surface and groundwater, and (2) those aimed at evaluating, characterizing, or mitigating contamination of soil or groundwater by hazardous substances.
The first type of environmental study is generally reserved for large-scale and federally funded projects. These studies should be initiated, and in some cases completed, during the feasibility and planning phases of a project to identify and avoid conditions that may prohibit or unduly delay a project (snail darter). Multi-disciplinary expertise, a thorough understanding of regulatory and project requirements, and "strong" project management are needed. The scope and nature of these studies vary but commonly follow the outline of an environmental impact statement.
The second type of environmental study has three phases (I, II, and III). Simply, phase I is an evaluation of the likelihood of contamination; phase II is a characterization of the nature and extent of contamination, and phase Ill is development of a plan for mitigation. After each phase, the necessity for further work is evaluated. Because of the severe penalties and liabilities associated with contaminated sites, a phase I assessment should be performed during feasibility and planning of any project regardless of size or type.
A phase I assessment has three components (research! reconnaissance and analysis), and the "study area" generally includes the subject property and neighboring properties within a reasonable distance. All activities should be performed or directed by a registered professional. Details regarding each component are presented in the following paragraphs.
The scope and components of phase II assessments vary immensely but are initially guided by the results of the phase I assessment. When soil or groundwater contamination is suspected or exists, the practices and theories employed for geotechnical exploration and analysis are ideally suited for the phase II characterization and many aspects of the phase Ill mitigation. Drill rigs, backhoes, geotechnical soil sampling methods, geophysical methods, and monitoring wells are common exploration practices, and theories regarding seepage and groundwater hydrology are used for quantitative evaluation of migration paths and rates of soluble and liquid contaminants.
- Research: The primary research activity is review of accessible public records and documents such as or regarding the following:
- State and federal superfund sites
- Underground storage tanks
- Current and historical maps and aerial photographs
- Generators, transporters, storers, disposers, and spills of hazardous waste or materials
- Active and closed landfills
- Discharge permits for air, surface water, and groundwater.
Other research activities include interviewing knowledgeable persons and reviewing property records. Examples of knowledgeable persons are past and current property owners, managers, tenants, neighbors, site development consultants and contractors, and government or agency personnel. Examples of property records are development plans, title records, and site material, operation and equipment data.
- Reconnaissance: This component consists of a relatively thorough visual inspection of the subject property and a cursory visual inspection of the subject neighborhood. Also, appropriate site interviews and inspection of suspect areas or items noted during research are performed. Occasionally, samples of soil, water, or building materials are obtained for laboratory analysis.
- Analysis: This component consists of evaluating the research and reconnaissance data to determine if contamination is likely and a phase II assessment is warranted and preparing a report. TEC's phase I reports detail and summarize assessment activities and discoveries, delineate environmental hazards noted in the "study area", and provide conclusions and recommendations regarding whether further assessment is necessary and what type of assessment activities are suitable.
Before phase II activities are initiated, safety and sampling protocol issues must be addressed. Many of these issues are outlined in OSHA, EPA, and state regulations. The regulations commonly require OSHA safety training, a safety and health plan, limited site access. monitoring equipment, and personal protective equipment before the phase II assessment is performed. Most of these requirements will remain in effect during phase III.
Phase Ill activities are almost completely site specific and are controlled by site and subsurface conditions, the nature and extent of contamination, safety and environmental regulations, local practices and capabilities, and economics. Most solutions fit into one of two categories:
Excavation and replacement of contaminated materials, which are commonly treated or disposed of by incineration, landfilling, or bioremediation
In situ treatment by vapor extraction and volatilization, bioremediation, groundwater extraction with treatment and recharge, encapsulation, solidification.