Method efficiency and signal quantification of bacteria for a groundwater transport experiment

摘要

Bacterial transport is a key process in delivery of microbes to contaminated sites for bioremediation of chemicals. However, relatively little is known about the geochemical and hydrologic factors controlling the mobility of bacteria and viruses within subsurface systems. Laboratory-scale column studies have provided useful information (Harvey et al, 1989, 1993). However, successful application to in situ remediation will require that one identify and understand properties relevant to transport in aquifers. Only through field experiments can one evaluate the scales of physical and chemical heterogeneity in natural aquifers that affect the transport of microbiota in ways not predicted from experiments conducted at the laboratory-scale. Bacterial transport field experiments cannot be replicated as can column experiments. Rigorous testing of experimental hypotheses will require comparisons of the mobility of multiple strains with contrasting transport properties under identical field conditions. Consequently, a technique is needed to permit the transport of multiple strains of bacteria to be monitored simultaneously in a single field experiment. Molecular techniques can also detect very low levels of injected bacteria. Polymerase chain reaction (PCR) has been used successfully for the detection of microorganisms. This paper explores the use of PCR for identifying and enumerating the arrival of several individual strains of bacteria at monitoring wells downgradient of an experimental tracer injection well.