Evolution of Vertical Profile Sampling and Measurement Methods for Contaminant Plume Characterization and Conceptual Modelling

As far back as the 1950’s, there is sScientific literature extending back to the 1950’s that shows  contaminant plumes in sandy aquifers delineated using various methods for obtaining hydrogeology and hydrochemistry data with depth,,,  or what we termed ‘vertical profiling ’ data profiles.  These studies have been essential for informing our professional judgment regarding the characteristics of groundwater plumes and the identification and importance of relevant physical, chemical and mircrobiologicalmicrobiological processes influencing their behavior.  Over the past decades, the science and practice of  high resolution vertical profiling has been evolveding evolvedas  with the development of new and varied tools are are  developed with improved resolution and measurement methods that addressforcapable of addressing different contaminant types and hydrogeologic environments. . Although vertical profiling techniques were  adopted early in contaminant hydrogeologyused early in the development of the contaminant hydrogeology profession, the collectionuse of these data sets to refine process-based site conceptual models (SCMs) is substantially underutilized.  This is the case even though continuous innovation has created versatility, reliability and cost savings. It is hypothesized that regulations and standardization of methods for compliance monitoring has short-circuited the importance of site characterization, , a distinct and important objective of the work that hinders progress toward development of informed SCMs, remediation system designs, performance evaluations and risk assessments.  . Although more awareness exists amongst  the groundwater industry professionals, there remain hurdles to  in modifying industry practice remain due to perceived costs, lack of experience and regulatory agency inflexibility. This isese hurdles are  causing a substantialignificant gap between methods applied in standard practice and  lag state of the science methods available for collection of apropriately-scaled, site- specific data, appropriately scaled, both in time and space, data. between state of the science and practice to gather appropriately scaled data, both in time and space, specific to the site conditions. A review of the science and how this has advanced most recently for contaminated sites in fractured sedimentary rock, an environment lacking rigorous field based research and method development until the past two decades, will be presented.  These fractured rock systems are important water supply aquifers and susceptible to contamination inputs, both from both above and from below, given societal needs for energy and waste disposal.