Evaluation of known or potential releases of hazardous substances and/or petroleum products to the subsurface completed by way of varying exploratory methods including but not limited to drilling, test-pitting, trenching, hand augering or other labor, vadose zone or groundwater monitoring wells, geophysical surveying, etc.
Soil, groundwater and/or soil gas/sub-slab vapor (see vapor intrusion section above) are sampled by way of appropriate methodology at targeted discrete depths or zones and analyzed for one or more contaminants of potential concern which may include metals, chlorinated solvents, petroleum hydrocarbons, polyfluoroalkyl substances (PFAS) and other organic or inorganic substances. The investigation approach is designed to evaluate the type, severity, and extent of contamination, and the controlling subsurface geologic or hydrogeologic pathways. Real-time soil, groundwater and/or soil gas/sub-slab vapor analyses may also be warranted if project decisions are required on a more rapid basis.
Data obtained during assessment work are used for a myriad of purposes including but not limited to understanding of fate and transport of contaminants, estimates of volume or mass of contaminants, environmental budget estimation, generation of site-specific, risk-based corrective action levels, development of conceptual site models and remedial specification and design evaluation/preparation.