Environmental Enlightenment #234
By Ami Adini -
Issued December 28, 2017

This is a SHORT, LIGHT and SIMPLE newsletter. Its purpose is to rekindle in the initiated concepts they have once learned, and enlighten the uninitiated on concepts they may have never heard of, but will understand once they are introduced to them.

Environmental Base Line (or Bench Mark)
in Real Estate Transactions

Absolutes do not exist, and values get established only by comparisons.

Suppose I said, “Three hundred.” Your immediate response could probably be, “Three hundred what?
     Light years?”

Suppose I said, “Three hundred dollars.”

Now we have a value that can be compared. We can buy so many almonds, rent a car for so many days, finance a date with a loved one, or do many other nice things. And when we look at the opportunities that three hundred dollars afford us, we shall undoubtedly arrive fast at the conclusion that five hundred dollars is more.



A “bench mark” is term used in the field of land surveying.

In establishing elevations of land features, the surveyor indicates feet above mean sea level. As it is impractical to run back and forth to the ocean every time we take a measurement, various bench marks are located throughout the land to indicate the altitude at their locations.

A typical bench mark is made of a round disk of metal embedded in a small monument of concrete with a punched point on the disk. The surveyor measures the elevations of the land features in that area relative to the known elevation of the point on the bench mark.


A “base line” is any line forming a side (A—B) of a triangle so that when the adjacent angles (alpha and beta) are measured, the relative position of a third point (C) (the tip of the triangle opposite the base line) is determined.



The principle of base line is used in land surveying and in navigation to locate various positions on the surface.



The concepts of bench mark and base line are same: establishment of an agreed-upon (arbitrary) value from which other, relative values are determined.




Certain real estate transactions take place in properties where subsurface contamination already exists or where an operation is planned that may cause contamination.

For example, an operator of refueling facility enters a lease agreement on the facility, or an industrial operation takes over a property.

In such cases, it would be prudent for all sides involved to establish an environmental base line (or bench mark) on the presence of pollutants in soil, soil-vapor, groundwater, sometimes indoor air, at the property.









A base line is established by collecting samples from certain locations and depths and analyzing for the chemicals of concern.

At the end of the lease, or in any time in the future, repeat samples can be taken, analyzed and compared.

The repeat sampling should be done in the same locations as the base line sampling.

There could be reasons for future sampling in other locations and analytical tests for other chemicals, as in the case where different operations enter the property, but such sampling does not belong in the context of base line sampling.

Happy New Year


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 Environmental Services, Inc.
Environmental Consultants & General Engineering Contractors
California Lic. #1009513 A B HAZ ASB
818-824-8102; mail@amiadini.com

Ami Adini is a veteran environmental practitioner with over 40 years of experience. He carries a Bachelor of Science degree (B.Sc.) in Mechanical Engineering including academic credits in Nuclear and Chemical Engineering and postgraduate education in these fields. His career includes design and construction of nuclear plant facilities, chemical processing plants and hazardous wastewater treatment systems. He is a former California Registered Environmental Assessor Levels I & II in the 1988-2012 registry that certified environmental professionals in the assessment and remediation of environmentally impacted land, and a Registered Environmental Professional (REP) since 1989 with the National Registry of Environmental Professionals (NREP). He is a California Business & Professions Code Qualifying Responsible Managing Officer (RMO) in the General Engineering Contractor classification with Hazardous Substance Removal and Asbestos certifications, and president of AMI ADINI ENVIRONMENTAL SERVICES, INC. (AAES), a general engineering contractor and consulting firm specializing in environmental site assessments, rehabilitation of contaminated sites and removal of environmental risks from real-estate transactions. (Contact Ami for a complete resume.) AAES provides practical solutions to environmental concerns using the highest standards of ethics and integrity while providing its clients with maximum return on their investments.