RA aka ESA

After reading chapter 14, there was one section in particular that stuck out to me; this section struck a chord after my recent involvement with an out of state project at work. Section 14-2 discusses hazard identification and the sources that can supply information that will create the most complete picture of a contaminated site’s history. This section essentially describes the work I do on a daily basis. As a hazardous materials specialist (fancy title for what I actually do), I spend most of my time completing Phase I Environmental Site Assessments (ESAs) in Arizona. Up to this point in my career, most of the sites I encountered have been fairly benign with a minimal amount of contamination usually occurring from leaking underground storage tanks at current or former gas stations. While for the sake of Mother Earth I am usually content not to uncover Love Canal on a regular basis, sometimes the monotony can take over and I wish I’d find something just a little more exciting than what I normally encounter.
Earlier this month I was able to work on a project in Dallas, TX involving the installation of new sewer line in the southern part of the city. While sewer lines are not exactly my forte, I was excited to work on a project out of state with different concerns and risks associated. While table 14-2 is specifically discussing the types of data that should be reviewed when working on a known contaminated site, the process for ESAs is very similar. In order to sufficiently assess the site, most of the items listed in the table must be reviewed for the complete identification of possible risks associated with the site, which may not be obvious. The text explains that by performing a site investigation, which parallels an ESA, a great deal of information can be gathered and ultimately “facilitate subsequent analysis.”
Due to the nature of the projects I usually work on (DOT projects with minimal subsurface disturbance), depth to groundwater in AZ (generally several hundred feet below ground surface (bgs)), the size and geology of the project areas I work on, any contamination I may encounter does not pose much of a risk to the project scope or surrounding area. In Texas however, there were several characteristics of the area which could affect how contaminants might impact the site: the depth to groundwater near the site was approximately 20 feet bgs, the geology and soils in the area differed greatly from the types I usually encounter in AZ and there was a creek which was located downgradient from the project area. Understanding the environmental characteristics of the site contributed to assessing the potential pathway for contamination, particularly important with the creek located only feet away and downgradient. The geologic and hydrogeologic assessment were important for painting a clear and complete picture to the client of why any contamination we found could pose a risk to the site and surrounding area. It was an important part of providing opinions to the client on what steps might be necessary if any contaminated sites were encountered.
Also important for adequately assessing the site for risk was understanding past land use and the history of the project area. The majority of the project area consisted of undeveloped, wooded land along the creek so at first glance, it didn’t appear that land use should be an issue. Obviously, if the site had been a former industrial plant, the investigation would have been geared toward that. This project taught me an important lesson on being thorough, however, no matter what the site may look like on paper. While finishing up the site reconnaissance I happen to notice something off in the distance which looked similar to 55-gallon metal drum. My sweet, naïve brain thought, “that can’t be a drum; we’re in the middle of the woods!” My Erin Brockovich brain, however, thought “That’s obviously a drum of a highly toxic chemical, likely contaminated the entire surrounding area and poisoning school children!” Turns out the truth was somewhere in the middle. Approximately 800 feet from the end of the project, an area of uncontrolled dumping was discovered. There were 55-gallon drums partially buried and rusted through along with other white goods and debris. One of the drums that was visible, contained the Dow Chemical logo and a partial label reading, “Hi-T” which after some Internet investigation was determined to be “Hi-Tri”, the shelf name for trichloroethylene. Because much of the debris was buried, it was not possible to uncover the extent of the dumping.

By performing a thorough site investigation and understanding the environmental characteristics and potential for the contaminants pathway, the client was given the information it will need in order to decide their next step. Understanding and informing the client that the geology and hydrogeology of the area will impact how any contamination associated with the dumping will migrate throughout the area is exactly what this type of risk assessment should provide. Like all risk assessments, a key factor is looking at all details and being thorough. If all of the possibilities are not investigated, details can be overlooked and risks may not be avoided. In this case, the client has been made aware of the dumping and will decide how extensive they’d like their phase II investigation to be.