ON DEMAND - Leveraging Site Groundwater Data and Statistical Methods to Derive Background Concentrations in Groundwater

A key consideration in the assessment of contaminated groundwater is the background concentration of analytes that may occur naturally in the groundwater system. Desktop review of publicly available data or installation and sampling of an upgradient groundwater monitoring well are routinely undertaken for smaller contaminated sites, particularly in metropolitan areas. However, assessment of background groundwater quality becomes more difficult at many sites, particularly those that are larger, have a long operating history or are in naturally mineralised areas, such as mining sites. Leveraging existing site groundwater data and adopting statistical methods is one way to derive background concentrations at such sites.

This webinar will compare and contrast the statistical approach adopted for two sites, both of which are large and have a long history of operation, but very different histories of groundwater monitoring. The approach adopted for both sites is generally consistent with recent guidance published by the Victorian Environment Protection Authority, with guidance from Queensland Department of Science, Information, Technology, and Innovation (DSITI), the United States Environment Protection Agency (USEPA), US Navy and Interstate Technology & Regulatory Council (ITRC) all referenced. For one site example presented, a similar approach was also used to assess background conditions in soils, allowing comparison with groundwater data for the same site and further reinforcing the conclusions.

These examples highlight the power of using statistical assessment of existing data appropriate to the form and scale of the monitoring records, combined with conceptual site hydrogeological understanding, to improve site assessment outcomes.

ABOUT THE SPEAKERS

Dana Windle
Technical Director (Hydrogeology)
ERM Melbourne

Dana has more than 13 years of experience as a hydrogeologist working in environmental consulting. Her experience with contaminated groundwater projects across Australia ranges from mining, chemical and manufacturing and power through to oil and gas sites, both large and small. Dana’s technical focus is on-site and hydrogeological assessments, conceptual site model development, fate, and transport of contaminants in groundwater, geochemical modelling, and groundwater remediation. Much of her work focuses on assessing groundwater at large sites and using complex datasets to develop robust hydrogeological conceptualisations, with an understanding of background groundwater quality often the key to this assessment.

Dr Tamie Weaver
Technical Fellow (Hydrogeology) and Partner
ERM Melbourne

Tamie has more than 30 years of experience as a hydrogeologist and has provided hydrogeological advice and technical leadership in site investigations. Her focus is on the assessment of fate and transport of organic and inorganic contaminants at operating and closed mine sites, power stations and industrial facilities. For over a decade Tamie was a lecturer at the University of Melbourne, teaching undergraduate, postgraduate and professional short courses in hydrogeology, hydrogeochemistry, and contaminant behaviour. She has been a consultant for over 15 years, with ERM for the last decade and is a co-author of EPA Publication 668, Hydrogeological Assessment (Groundwater Quality) Guidelines.