As a geologist with more than two decades of environmental experience, I am admittedly biased, but I will tell you, without hesitation, that if you have any hope of succeeding in your environmental remediation efforts, you must spend the necessary time up front in assessing your site. In fact, if you have ever been to any of our seminars or webinars or have read any of our articles, you know that the Dragun culture is one based on being very meticulous.
While it may seem somewhat extreme, if you assume everything you do during site investigation and characterization (i.e., collection of soil samples, groundwater samples, etc.) will have to be defended in court, you approach this effort with a different “attitude.” But on those occasions when a simple phase two environmental assessment ends up in court, it’s comforting to know you have done your job in generating meaningful data.
With this said, briefly, here are some environmental site assessment essentials as they relate to obtaining subsurface soil and rock samples.
Environmental Site Assessments: Logging the Soil Sample
Take your time. Remember, when anyone is doing a subsurface investigation, they are taking a very small sample (each core is just a few inches in diameter) of the “larger geology” and, in a sense, connecting the dots. So the person “logging” the (soil or rock) core has a very important job; they must, with great accuracy, describe the soils in the proper geological terms. This accurate description of the soil begins to paint a picture of the subsurface conditions, and, if this description is wrong, it can stymie every other step in the process. In Ontario, all drilling activities should be conducted under the supervision of a Professional Geoscientist or a Professional Engineer who is experienced in geology.
Soil cores must be properly profiled to begin to understand site conditions
But … don’t take too much time. In the last paragraph, I mentioned how important it is to make sure the site investigation is done properly; however, that does not necessarily mean you need to spend an inordinate amount of time on each boring. After all, you are spending a lot of money to get these soil boring (or rock coring) logs. You want enough information to move onto the next step. These logs need to be detailed enough so you have the right information (such as where permeable zones begin), but it does not mean generalizing it just so you can get done and get out of the rain, snow, heat, etc. The soil logs need to properly document the underlying geology – no more and no less.
You are relying on the Geologist to provide you with good, quality data and to interpret the results. However, the log descriptions are still subjective and may vary, even between experienced geologists (depending on their personal experiences). It is necessary to provide hard proof (analytical data) for the descriptions so that you know you can rely on the data. Simple tests, such as grain-size analysis, can provide this “proof.”
Environmental remediation success rests on the first step
Knowing the geology under your site is an essential first step in understanding how your site may be impacted or in preparing effective soil or groundwater remediation methods. Unfortunately, far too often there is a rush to get to the latest and greatest environmental remediation technology, which is destined to fail if you don’t first understand your geological conditions.
If you have questions about environmental site assessments or environmental remediation, please feel free to contact me at 519-979-7300, ext. 126, or by email aainslie@dragun.com