Reducing Costs and Improving Results through Comprehensive Site Remediation

Owners of sites with subsurface contamination know how time-consuming and challenging it can be to eliminate VOCs or other hazardous materials from groundwater or soil. For many, it seems like just when one area has been remediated, another area becomes problematic, causing additional rounds of investigation and clean-up efforts, which are always accompanied by increased costs. In my experience, some consultants will treat each instance of hazardous contamination at a site as an isolated event, leading to a game of remediation whack-a-mole, in which the root of the issue never actually gets addressed. Remediation efforts that take a comprehensive approach and consider the big-picture as well as the individual components of contamination make a much larger impact on the environment and save money for site owners in the long run.

Developing a conceptual site model

Soil and groundwater can be highly transmissive media depending on the contaminants, which is why it can be problematic to treat contamination issues as isolated events. Site owners may not be aware of the extent to which groundwater affects the transport of certain contaminations both on and off-site, and in order to get a full picture of conditions, a conceptual site model (CSM) must be generated. The CSM is a living construct that should be updated and revised as investigations throughout the site provide further information that details contaminant distributions, exposure pathways, and potential receptors. Identifying these key pieces of information are fundamental in formulating an appropriate remediation response.

When beginning an investigation, it can be easy to dive into your own inquiries without looking at existing site data, but to skip this step might cause unnecessary expenditures and redundant research efforts. State soil surveys, historical records, aerial photographs, information from past site investigations, and information from other contaminated sites in the region can all be crucial in developing a CSM. Once this information has been compiled and organized, you can use the CSM to identify your data gaps and guide the necessary remaining investigative measures at the site and any surrounding areas that might influence or be impacted by present contaminants.

Acting on site-specific needs

Each site has its own unique set of challenges to face, and taking the time to develop a detailed CSM will allow you to identify those. If you haven’t been working with an expert to develop your CSM, it is always helpful to solicit the opinion of someone with experience in hydrogeological contamination at this point, as you will likely be required to make important decisions about the investigation and cleanup of your site based on your CSM and subsequent models.

Creating a groundwater flow or fate and transport model can be helpful in various ways: determining potential impacts to nearby wells or surface waters, estimating vapor intrusion from groundwater and soils into buildings, and identifying potential key data gaps you may have overlooked when investigating your site. However, there are variations on these types of models, and the process of choosing the best one for your site should include an analysis of any given model’s applicability to the specific needs of your site. These models can be highly useful for simulating the ways in which contaminants are moving through and interacting with the subsurface at your site, but using them without a thorough understanding of the natural system you’re dealing with will result in a less accurate and effective end result.

Site contamination can be much more complex than many property owners imagine. At times, it may seem that a quick fix approach will allow you to solve an isolated contamination problem and carry on with business as usual. While this might help in the short-term, the chances of having to deal with continued issues increases as long as events are treated as one-offs that are unrelated to previous and future areas of ecological or environmental concern. Working with a consultant to gain a comprehensive understanding of the ways in which your soil and groundwater contamination might impact the surrounding environment and surface water will ultimately reduce costs. This approach allows you to effectively and efficiently deal with the root cause of the problem rather than multiple manifestations of that same cause individually resulting from an ineffectual or incomplete remedy. A comprehensive approach to site remediation will also boost the resulting effectiveness of your efforts, preventing problems before they ever start.

Author

Jason House Practice Leader Hydrogeology

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