Third-Generation (3G) Site Characterization: Cryogenic Core Collection and High-Throughput Core Analysis - An Addendum to Basic Research Addressing Contaminants in Low Permeability Zones - A State of the Science Review SERDP Project ER-1740
Modern contaminant hydrology has brought us to the realization that decisions regarding management of subsurface contamination at need to be based on an understanding of all contaminant phases (i.e., aqueous, non-aqueous-liquid, sorbed, and vapor) and the biogeochemical conditions in which the contaminants are present. The practical approach for collection and analysis of frozen-cores presented here represents an important new tool for improving that understanding. Uniquely, core samples frozen in situ before recovery can preserve pore fluids, volatile compounds, dissolved gases, redox conditions, mineralogy, microbial ecology, and pore structure. Furthermore, in situ freezing improves quality of recovered core by preventing materials from dropping out of sample liners during recovery to ground surface. Collectively, steps followed for collecting frozen cores are referred to here as cryogenic core collection (C3).
Because freezing provides effective field preservation, frozen cores can be processed efficiently under controlled laboratory conditions to resolve a broad spectrum of chemical, physical and biological characteristics. Critically, processing core in the laboratory simplifies field work and improves the resources (e.g., anaerobic chambers) that can be utilized in preparation of samples for analysis. Furthermore, laboratory processing frozen cores allows “production line” processing and analysis of large quantities of samples, referred to here as high-throughput core analysis.