Investigation & Remediation
Circumstances that warrant environmental investigation and/or remediation differ from site to site and will involve varying levels of complexity.
Conducting such activities at sites of environmental concern is to ultimately assess if/what risks exist and to determine if conditions at the site are protective of human health and safety, and the environment. Response actions are driven by a state’s environmental regulations and guidelines – this requires an expertise to navigate and implement them effectively. Whether working within a state’s voluntary cleanup program, a leaking underground storage tank (LUST) program, or another program where the state’s environmental agency or EPA has mandated action, Certus can help devise an appropriate work plan and implement necessary investigative/remedial activities, and we are experienced in collaborating with state/federal regulators to devise a strategy that is appropriate to satisfy the intended project objectives whether it be to achieve closure or a form of no further action.
The basis for performing investigative activities is to determine if/what impacts exist in environmental media (soil, groundwater, surface water, sediments, and/or air), and if present, to characterize the nature [i.e the originating source(s) of contamination] and extent (i.e. degree contamination existing vertically and horizontally). Remedial actions may subsequently be taken to eliminate or reduce grossly-impacted source material; for example, this includes, but is not limited to, soil and/or groundwater with non-aqueous phase liquids (NAPL) – sometimes referenced as “product”. The number of sampling locations, and number and type of environmental media to be sampled, varies for each site – this warrants consideration of the different investigative tools and technologies utilized today. Certus devises a strategy that effectively targets the identiﬁed concern(s) and utilizes approaches and technologies that are most cost-efﬁcient for our clients.
Prior to conducting any onsite investigative or remedial activities, its imperative that your consultant’s planning and coordination include important tasks that should not be overlooked. For example, an adequate review of the available site information for the preparation of a site-specific scope of work; procurement of competent contractors; preparation of a health and safety plan (HASP) – this includes identifying appropriate level of personal protection equipment (PPE) for site workers; notifying MissDig a minimum of 72 hours to identify and/or clear utilities prior to initiating site activities; and complete applicable site notifications (e.g. regulatory agency onsite work notices) and permitting [e.g. local unit of government (LUG) and/or Department of Transportation (DOT)].
As important as the initial planning and coordination is, it may be as equally important that your consultant has the the ability to adapt to the unforeseen circumstances that may arise while afield – managing unexpected USTs, strategically adjusting soil boring locations due to previously unknown physical obstructions, unfavorable/unstable hydrogeologic (soil and groundwater) conditions , encumbered site access, etc. – Certus is experienced in adapting to these types of situations.
Vapor Intrusion (VI) has become a significant point of emphasis within the past decade or so, specifically with regard to anthropogenic chemicals such as volatile organic compounds (VOCs) and select semi-VOCs (SVOCs) – most notably, petroleum hydrocarbons, chlorinated solvents, elemental mercury, and select polychlorinated biphenyls (PCBs).
Some state regulatory agencies have reviewed historic files and “re-opened” previously closed sites that have demonstrated environmental impairments potentially characteristic of VI concerns. Although VI is currently an evolving concept, it’s not new and may be recognizable to many when thinking of radon gas infiltrating residential basements through sump basins or cracked foundations. VI essentially occurs when the vapor phase of certain chemicals migrate through subsurface soils (i.e. soil gas) and infiltrate buildings, potentially putting us at risk when unacceptable concentrations accumulate in indoor air. Regardless of whether these vapors originate from impacted soil and/or groundwater sources onsite or offsite, the risk may exist nonetheless because vapors can migrate along utility trenches and through sewers, and infiltrate indoor air spaces via utility openings or cracks in foundation walls and slabs. In order for VI to be considered a complete exposure pathway posing a health risk, the following must be present: 1) a VI source, 2) migration route(s), and 3) a human receptor – if one variable is absent, the pathway is not considered relevant.
It’s important to initiate a VI assessment by first understanding all site-specific conditions to the extent feasible. Developing a conceptual site model (CSM) is a critical part of the initiation process – a CSM is essentially the compilation of information including, for example, the nature (e.g. petroleum hydrocarbons, chlorinated solvents, and/or other), location, and concentration of source material(s); hydrogeologic conditions at the site; building characteristics; and identification of potential receptors. Not to be overlooked, it’s just as important to recognize a CSM may require modification as new information becomes available during a VI assessment.
The VI concept isn’t devoid of challenges. Indoor air quality may also be influenced by building materials and products we utilize in our daily routines. Such products may include cleaners, adhesives, and fuels that produce vapors as well as or other products that off-gas chemical vapors similar in nature to those commonly of concern. However, whether the vapors originate from products we commonly use or from contaminated soil and/or groundwater, it’s imperative that you yourself, your employees, and/or patrons are not exposed to unacceptable health risks resulting from VI.
It may be reasonable to rule out VI as a concern utilizing screening tools or through an investigative approach (i.e. soil gas and/or sub-slab sampling). Whether using the tiered approach outlined in the American Society for Testing and Materials (ASTM) standard ASTM E 2600-10, Standard Guide for Vapor Encroachment Screening on Property involved in Real Estate Transactions or regulatory agency environmental guidance and practices, Certus will evaluate and implement the most efficient strategy to assist you in performing a VI assessment/investigation at your site.