Phase II Environmental Site Assessments & Phase III Site Characterization

Based on the findings of the Phase I ESA, APES associates may recommend that a Phase II investigation be conducted to determine whether the recognized environmental conditions identified in the Phase I ESA have in fact adversely impacted the site resources (soil, groundwater, soil vapor, indoor air) or pose a risk to human health. The APES Team has completed hundreds of Phase II environmental assessments across California. These subsurface investigations can be initiated for multiple reasons, but are most often conducted in response to recognized environmental conditions identified during an initial Phase I ESA. Investigation strategies vary from site to site, but are designed by incorporating a multitude of site-specific factors including: identified current or former underground structures, current or former hazardous materials storage areas, site-specific high risk locations identified at the property, suspected contaminants of concern originating both on and offsite, site soils and geology, site hydrogeology, depth to groundwater, and groundwater gradient, site infrastructure, future land use changes or development plans, and many more.

After an initial Phase II Site Assessment discovers contamination at a Site, the next step is to continue subsurface investigations to fully characterize the contamination both on- and offsite and complete a Conceptual Site Model. Site characterization is an essential next step in addressing known or suspected contamination. APES associates will likely employ a variety of subsurface investigation techniques to determine the vertical and lateral extent of contaminants impacting the site, as well as assess the subsurface geology that will determine how contaminants migrate beneath the surface across the site. By determining the vertical and lateral extent of contaminants, and having an understanding of how the site geology will affect the behavior of contaminants in the subsurface, APES professionals are able to develop a detailed Conceptual Site Model (CSM) that will help guide future investigations and remedial actions. A detailed CSM allows us to develop the most efficient and cost-effective approach to site remediation. At APES, we don’t subscribe to a one-size-fits-all approach, and instead customize our approach to meet our client’s goals.

Vapor Intrusion/Vapor Encroachment: 

When vapors from on or off site releases have the potential to migrate into the air we breathe, the path to closure can be difficult to navigate. At APES we work diligently and collaboratively with our clients and regulators to develop efficient and cost effective mitigation strategies for vapor intrusion that minimize business risks while protecting human health. Our team stays up to date on current research and the ever evolving regulatory guidance to help ensure safe, cost effective solutions to vapor intrusion concerns. By staying up to date on current research and novel approaches to vapor intrusion mitigation, the APES team has an ever growing understanding of strategies to employ to avoid excessive costs and find the least intrusive vapor intrusion solutions.