To better understand the cause of high counts of potentially pathogenic fecal indicator bacteria (FIB) in the watersheds of the Mahaulepu Valley and Waikomo Stream in southeast Kauai, the Hawaii Department of Health (DOH) commissioned a study by Berkeley Lab microbial ecologists Gary Andersen and Eric Dubinsky.
Anderson is a senior scientist in Environmental Genomics and Systems Biology (EGSB); Dubinsky is a guest scientist in EGSB. The duo is frequently invited to lead microbial water assessment projects thanks to their expertise and the PhyloChip, a credit card-sized microbial detection technology invented by Andersen and others at Berkeley Lab.
“The PhyloChip is able to rapidly profile the entire microbial community present in the water samples and use this information to detect bacteria that are unique to specific animal or human sources,” said Dubinsky, who is also a project scientist in UC Berkeley’s department of Environmental Science, Policy & Management. “Unlike conventional fecal contamination tests, which use a handful or even just a single species to identify the potential for contamination, our approach uses a diverse set of hundreds of different bacteria that are characteristic of each fecal source.”
After analyzing samples from 13 inland and coastal sites taken over the course of one year, the scientists concluded that there was no detectable human sewage in the Mahaulepu watershed, nor was there a significant presence of livestock or avian wildlife fecal matter. They propose that the historically high FIB levels are a consequence of using old-school testing methods, none of which were designed for use in the tropics.
Read more in the Berkeley Lab News Center.