Identification of subsurface microorganisms at Yucca Mountain; Fourth quarterly report

Bacteria isolated from water samples collected in a series of ground water springs have been isolated, enumerated, and identified from twenty six sites. Ten sites were sampled in Death Valley, California and sixteen sites were sampled in Ash Meadows, Nevada. Replicate samples were collected and tested from four locations. All water samples were collected in conjunction with the HRC chemistry group conducting ground water fingerprinting studies. The protocol for collection of samples, as described in the 3rd quarterly report, specified aseptic collection in sterile screw-capped containers and transportation on ice to the HRC microbiology laboratory. All samples were inoculated by spread plating onto R2A (Difco Laboratories, Detroit, MI) bacterial culture medium. the R2A plates were then incubated at 28{degrees} for 5--7 days and colonies wee counted with the aid of a grid template and magnifying lens