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Don't Let Contaminated Fill Spoil Your Project

Land development today is changing for several reasons. Partly because of the heightened awareness toward environmental contamination, the litigious society we live in, and also the desire for greener, more sustainable developments. For example, redevelopment of Brownfields sites is on the rise, and the recycling of all types of building materials is increasing, including soil. As a result, there are fewer and fewer pristine sites without flaws left for development, and this can be true for borrow sources of soil as well.

A problem that is becoming more common today is associated with the “brokering” of fill. In an effort to find cheap fill, earthwork contractors often broker fill between project sites. Similarly, if excess excavated soil is leaving your site and being “brokered” without adequate controls in place, undue headaches, liabilities, and costs can result later.

Liabilities Associated with Borrow Soil
Project specifications will typically call for fill to be “material taken from approved sources to make up any deficit of excavated materials.” The engineering properties for suitable materials are often specified. However, when it comes to environmental contamination considerations you will often see language similar to “…material shall be clean,” “…free of other deleterious matter,” or “…not contaminated with hydrocarbons or other chemical contaminants.”

If the borrow soil has a strong chemical odor the user may suspect it is contaminated and check further. However, many types of chemical contamination have no visible signs, like lead or arsenic contamination. Unfortunately, there is no litmus paper test to determine if a soil is contaminated or not. Potential liability to owners, contractors, architects, engineers, and consultants resulting from uncontrolled fill is tremendous.

A Better Approach
Until appropriate measures have been taken or put in place to adequately manage the potential risk, every site and project should be approached as if there is a possibility of environmentally tainted fill material being brought onsite, or may leave the site. This starts with understanding the site data and its limitations, and then writing the earthwork specifications for borrow and off-site disposal of excess soil so that it adequately addresses your specific project scenario. Some tools Terracon has used successfully to manage these risks have included the following:

  • Requiring a Phase I environmental site assessment for the prospective borrow source(s). This is a non-intrusive study that looks at the environmental history of the site. This study can reveal a lot, including whether or not further concerns may be warranted.
  • Specifying the analytical testing to be performed, the testing frequency, and the concentration above which the fill soil would be considered unacceptable or contaminated. Again, it’s not about catching the gross contamination visible by the naked eye, but rather to catch metals contamination where there are no visible signs.
  • Developing a site-specific Soil Management Plan (SMP) when there will be soil leaving your site. The SMP addresses the characterization, handling, transportation, disposal/recycling, and documentation requirements of soil going off-site, and should be made a part of the contract documents. The additional cost is nominal and the peace of mind it provides is well worth it.

For land development projects, or any project involving earthwork or fill soil, if it is contaminated it is the last thing you want on your project site. Remember to consider how costly undocumented sources of fill can be, and know how to guard against it being used on your project.