E.F.A. I
Geological Characterization
The geologic characterization component of a site investigation provides insight regarding contaminant
distribution and transport. Components of a geologic investigation usually include:
Drilling and logging of the boreholes and/or trenches
Soil retrieval for textural classification and/or physical testing
Soil sampling for chemical analysis
The first step is to acquire and review the original field borings and/or trench logs. Compare the information on
the field logs and final logs in the report for consistency. If geologic cross-sections or fence diagrams are included
in the report, examine them for consistency with the field log/trench descriptions.
When reviewing boring logs, examine their placement relative to historical information, especially areas of known
or suspected contamination. This review often provides insight as to whether additional borings and/or sampling
are necessary. Given that site access agreements among multiple parties are usually required in order to perform
additional sampling, the sooner the data sufficiency of the geologic information is identified, the sooner the site
access agreements and sampling can proceed.
The sufficiency of existing geologic information can be determined via the following steps:
Ascertain whether the drilling method employed allows an accurate description of the subsurface.
Determine whether the number of soil borings is sufficient to characterize the geologic environment
relative to litigation allegations.
Decide whether the borings are sufficiently deep to characterize the geology of interest.
Decide whether the borings are spatially located so as not to preclude developing useful information for
geologic characterization.
The drilling technology impacts the geologist’s ability to describe the soil and/or geologic setting. Reliance solely
on mixed drill cuttings from air or mud rotary drilling, for example, precludes the ability to provide detailed
descriptions of stratigraphic changes. Continuous hollow stem augering and/or most push technologies that
retrieve an in situ soil sample provide this level of detail.
Groundwater Characterization
The hydraulic properties of an aquifer are commonly estimated or measured as part of a groundwater
characterization investigation. The determination of how these properties are measured and their reliability is one
factor in evaluating contaminant transport and risk assessment models.
Hydraulic properties and their definitions include:
1. Hydraulic conductivity: The rate of flow of water in gallons per day through a cross-section of 1 ft 2 under a
unit hydraulic gradient at a prevailing temperature.
1 Forensic Techniques Used in Environmental Litigations | Environmental
Forensic Analysis I
Geological Characterization
The geologic characterization component of a site investigation provides insight regarding contaminant
distribution and transport. Components of a geologic investigation usually include:
Drilling and logging of the boreholes and/or trenches
Soil retrieval for textural classification and/or physical testing
Soil sampling for chemical analysis
The first step is to acquire and review the original field borings and/or trench logs. Compare the information on
the field logs and final logs in the report for consistency. If geologic cross-sections or fence diagrams are included
in the report, examine them for consistency with the field log/trench descriptions.
When reviewing boring logs, examine their placement relative to historical information, especially areas of known
or suspected contamination. This review often provides insight as to whether additional borings and/or sampling
are necessary. Given that site access agreements among multiple parties are usually required in order to perform
additional sampling, the sooner the data sufficiency of the geologic information is identified, the sooner the site
access agreements and sampling can proceed.
The sufficiency of existing geologic information can be determined via the following steps:
Ascertain whether the drilling method employed allows an accurate description of the subsurface.
Determine whether the number of soil borings is sufficient to characterize the geologic environment
relative to litigation allegations.
Decide whether the borings are sufficiently deep to characterize the geology of interest.
Decide whether the borings are spatially located so as not to preclude developing useful information for
geologic characterization.
The drilling technology impacts the geologist’s ability to describe the soil and/or geologic setting. Reliance solely
on mixed drill cuttings from air or mud rotary drilling, for example, precludes the ability to provide detailed
descriptions of stratigraphic changes. Continuous hollow stem augering and/or most push technologies that
retrieve an in situ soil sample provide this level of detail.
Groundwater Characterization
The hydraulic properties of an aquifer are commonly estimated or measured as part of a groundwater
characterization investigation. The determination of how these properties are measured and their reliability is one
factor in evaluating contaminant transport and risk assessment models.
Hydraulic properties and their definitions include:
1. Hydraulic conductivity: The rate of flow of water in gallons per day through a cross-section of 1 ft 2 under a
unit hydraulic gradient at a prevailing temperature.
1 Forensic Techniques Used in Environmental Litigations | Environmental
Forensic Analysis I
