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Options & Tools Available in Addressing Historical Site Contamination Issues


Once you have documented your property is contaminated, what are your options?

Once you receive that Phase II Investigation report that shows your property has some contamination issues, don’t panic yet.

Everyone has heard the horror stories about millions spent on cleaning up site contamination that occurred half a century ago. Fortunately, we have come a long way in understanding behavior, fate and transport of chemicals in the environment.  Additionally, site cleanup decisions are almost entirely risk-based, meaning contaminated soil does not need to be remediated to background conditions, and groundwater does not always require treatment to potable water standards.

In Texas, most contaminated sites are subject to the technical regulations under the Texas Risk Reduction Program (TRRP) or the Petroleum Storage Tank (PST) rules. Both of these programs have evolved in pragmatic ways to rely heavily on evaluating individual exposure pathways and requiring response actions only for those pathways that suggest unacceptable risks to human or ecological receptors.

Here are some examples:

Alternate Cleanup Standards

Under the TRRP, the Texas Commission on Environmental Quality (TCEQ) has provided a number of tools that allow consideration of site-specific factors to better evaluate contaminate fate and transport.  For example, Tier 2 cleanup calculations allow for soil parameters specific to the Site area to be used.  Tier 3 calculations allow for even greater flexibility using more complicated fate and transport models and site-specific conditions.  Chemical-specific cleanup standards can be developed for complex petroleum mixtures using a spreadsheet model that inputs toxicological data for each carbon range present in the mixture.

Perhaps the most significant tool that has been made available to address groundwater contamination is the Municipal Setting Designation (MSD).  MSDs are simply restrictions on groundwater use such that water under the affected property cannot be used for potable purposes.  Of course, shallow groundwater in many urban settings in Texas is not used for potable purposes, and drinking water is obtained from deep wells or surface water reservoirs, so the MSD simply formalizes what already exists.  Since the zone of affected groundwater most often impacted by surface spills is a shallow (often perched) water-bearing unit, the MSD is a cost-effective solution.  MSDs are unique in the environmental remediation arena because they require local as well as TCEQ concurrence, and will often involve public meetings where the project is described to landowners and water well owners.  This amount of transparency is unusual for environmental projects, however, the benefits are significant, and can save hundreds of thousands on expensive groundwater remediation options.

Petroleum Storage Tank Program

Cleanups at filling stations are associated with releases of petroleum substances, such as gasoline or diesel fuel, from underground storage tanks (USTs) and/or aboveground storage tanks (ASTs). The most common chemicals of concern (COCs) found at LPST sites are petroleum hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX), and methyl tert-butyl ether (MTBE).

Did you know there have been over 26,000 leaking tank incidents reported in Texas?  The TCEQ’s Leaking Petroleum Storage Tank (LPST) Program has gained a wealth of information since the 1990s on how typical petroleum hydrocarbons behave in the environment.  As a result, we now know that natural biodegradation is a very effective mechanism for the attenuation of petroleum plumes, and therefore cleanup efforts can be reduced if no human or ecological receptors are harmed by the plume.  Consequently, LPST cleanup focus on environmental risk assessment (such as proximity to water wells and surface water bodies) and obtaining data to document that the plume is stable and declining over time.  Actual cleanup of the plume is seldom required except in sensitive aquifers where shallow groundwater is a local source of drinking water.

These are just a few of the tools and pragmatic approaches that can keep your contaminated site from ruining your project.   W&M Environmental has many years of experience in environmental cleanup and management.  For more information please contact Clay Snider or Frank Clark.

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