DEVELOPMENT OF A RAPID C-14 BASED FIELD METHOD FOR ASSESSING POTENTIAL BIODEGRADATION OF ORGANIC-COMPOUNDS IN SOIL AND SEDIMENT SAMPLES

The objective of this investigation was to develop and implement a bio degradation assay that could be completed within hours in a mobile fie ld laboratory. We sought to identify portable instruments that could f unction as alternatives to a standard beta-scintillation counter which , itself, is not readily transportable to a field setting. A beta-scin tillation type survey meter responded linearly and with 29% efficiency in the laboratory when calibrated with standard C-14-bicarbonate solu tions spotted and dried onto copper disks. Efficacy of the beta-probe/ copper disk procedure in quantifying microbial mineralization activity was examined in laboratory incubations of sediment amended with both C-14-p-hpdroxy-benzoate and naphthalene. The procedure was implemented in a field setting in which four field samples were processed in a mo bile laboratory. Six percent of the C-14 naphthalene was mineralized i n 2 1/2 h by naphthalene-contaminated samples, while no activity was d etected in samples from adjacent uncontaminated locations.