Surface Water Quality along the Central John Muir Trail in the Sierra Nevada Mountains: Coliforms and Algae

摘要

Ursem, Carling, Scott Evans, Kemal Ali Ger, John R. Richards, and RobertW. Derlet. Surface water quality alongnthe central John Muir Trail in the Sierra Nevada Mountains: Coliforms and algae. High Alt. Med. & Biol. 10:349–n355, 2009.—The John Muir Trail ( JMT) in the Sierra Nevada Mountains of California is one of the most popularnalpine wilderness trails in the United States, where backpackers depend on trailside water sources for morenthan 335 km (208 miles). This study addressed the risk of acquiring waterborne disease by analyzing prevalencenand changes in coliform bacteria and Escherichia coli (E. coli) in lakes and streams adjacent to the central JMT.nChlorophyll-a levels were also measured as an indicator of high elevation eutrophication. Categories of envi-nronmental land use which might affect water quality were defined as: Pristine areas rarely traversed by humans;nBackpack off-trail areas not traversed by pack or stock animals; and Multiuse areas with backpacker and ani-nmal use. We analyzed surface water at 36 different sites three separate times over an eight week period in thensummer of 2008. Chlorophyll-a concentration increased significantly in Backpack and Multiuse sites over thensummer months, but not in Pristine sites. Similar results were obtained for coliforms, with prevalence alsonincreasing significantly over the summer months in Backpack and Multiuse sites. There was a much highernprevalence of E. coli in Multiuse sites compared to Pristine and Backpack sites. Our study provides evidencenpack and stock animals serve as a source of microbial contamination of water along this section of trail.