Environmental Enlightenment #66

By Ami Adini - Reissued December 10, 2014

This is a SHORT, LIGHT and SIMPLE newsletter. Its purpose is to rekindle in the initiated terminology they have once learned, and enlighten the uninitiated on terms they may have heard but never known the meaning of.

Finding Buried Objects

Real estate transactions happen in times to hinge on the potential presence of buried objects such as historical underground storage tanks, chemical storage drums, pipelines and others. In another line of activity, safety of construction projects depends on exact knowledge of buried objects in the planned excavation areas. Hitting an unknown, high pressure gas line can and has caused loss of lives.

We need tools to assist us in the exploration of buried objects, and such tools should be capable of doing the work without disturbing the surface.

The field of geophysics comes to our need.

Geophysics is a compounded word: geo plus physics.

Geo is earth in Greek, from Gaia, the mythological goddess personifying earth. GAIA was Mother Earth, an ancient primeval goddess who emerged at the creation of the universe, second only to Khaos (Air). She was depicted as a buxom, matronly woman, shown half risen from the earth, unable to completely separate herself from her element.

Physics derives from Latin physica: natural science, from Greek physika: of nature.

Physics is the science that deals with matter and energy and their interactions. Physics includes such fields of mechanics, optics, heat, electricity, magnetism, atomic structure, and others. It is the study of how objects (from the very tiny to the very big) behave.

Geophysics is the study of the physical properties of the earth and the composition and movement of its component layers of rock.

Geophysics is applied to mining exploration to detect zones that could be characterized by physical properties such as magnetism, gravity or conductivity. It studies the physics of the Earth, using the physical principles underlying such phenomena as seismic waves, heat flow, gravity, and magnetism to investigate planetary properties. It is the study of the physical properties of rocks and minerals.

Assessment of contamination in the subsurface is done by advancing test holes to the desired depths and collecting samples of soil and/or groundwater. Drilling involves the inherent hazard of colliding with unknown buried objects such as gas lines, power lines, petroleum pipelines, fiber-optic arteries, water mains, underground storage tanks and connected gasoline lines. Such encounters involve great risks of explosions and attendant losses in life and property.

It is crucially important to identify buried utilities in areas of intended excavations. Tools are needed that will identify underground targets without actually intruding on the subsurface world.

Also, in the exploration for environmental liabilities in real estate transactions, it is not uncommon to find records of historic existence of underground tanks with no information on their ultimate fate: Have they been removed? Are they still there? Where?

We need a tool that, with minimal interference with the current conditions of the property will help us find buried objects.

The science of Geophysics has long used non-destructive methods to identify subsurface characteristics of underlying rocks, formations, minerals and groundwater. These tools are used today extensively to assist in our environmental needs for the exploration of subsurface features and buried objects.

In this and forthcoming articles we shall look at the features and uses of these tools.

In assembling the articles we relied on information gleaned from several sources on the World Wide Web. A major source has been a U.S. EPA publication. All information copied, to the best of our knowledge, has not been copyrighted. For lack of space, a general credit and gratitude is hereby expressed to all other sources without identifying any. They are easy to locate through key words in a good search engine. We are biased to Google and a hearty appreciation to the creators of this engine is hereby expressed.

Surface geophysical methods are generally non-intrusive and can be employed quickly to collect subsurface data.

Data collected with geophysical tools are often difficult to interpret because a given data set may not indicate specific subsurface conditions. Instead, data provided by these tools indicate anomalies which can often be caused by numerous features. As a result, geophysical methods are most effectively used in combination with other site information (e.g., data from different geophysical methods, sampling and analytical tools, geological and historic records, anecdotal information). A combination of these sources is often necessary to resolve ambiguities in geophysical plots (i.e., the graphical representation of data produced by a specific method).

The most appropriate geophysical methods for UST site investigations are:

  • ground penetrating radar (GPR);
  • electromagnetic methods;
  • electrical resistivity;
  • metal detection;
  • seismic methods; and
  • magnetometry.

All geophysical methods have limitations that will affect their applicability at specific sites.

In the next articles we shall deal with each of these methods.

You can find past issues of our  "Environmental Enlightenment" at amiadini.com Wealth of information about environmental site assessments in the real estate transactions and issues concerning assessment and cleanup of contamination in the subsurface soil and groundwater.

Call me if you have any questions. There are no obligations.

Ami Adini
Ami Adini & Associates, Inc.
Environmental Consultants
Underground Storage Tank Experts
818-824-8102; 818-824-8112 fax

Ami Adini is a mechanical engineer, California Registered Environmental Assessor, Level II (Exp.), and president of AMI ADINI & ASSOCIATES, INC. (AA&A), an environmental consulting firm specializing in all phases of environmental site assessments and rehabilitation of contaminated sites. AA&A specializes in practical solutions to environmental concerns using the highest standards of ethics and integrity while providing its clients with maximum return on their investments.