期刊名称：Journal of Natural and Environmental Sciences
印刷版ISSN：1309-7474
出版年度：2012
卷号：3
期号：1
页码：9-18
语种：English
出版社：Journal of Natural and Environmental Sciences
摘要：Bacteria of fecal origin are the primary cause of surface water contamination in the US. E. coli is used as an indicator of fecal contamination and detection of E. coli in a water body above regulatory standards poses a potential health hazard. Various sources contribute to the bacterial contamination of a water body and these sources need to be identified and quantified to estimate bacteria loads in the waterbody accurately. In-situ re-growth is also believed to be a considerable source of E. coli in many cases. Also re-growth of E. coli in landscapes due to favorable environmental conditions (e.g., rainfall after dry weather conditions) is one of the major phenomena affecting E. coli concentration in streams. The objective of this study was to identify, characterize, and quantify E. coli concentration from feces of four different animal species and monitor survival, growth and re-growth at four different temperatures and moisture contents over a period of seven days. Wildlife and range cattle fecal samples from the Cedar Creek watershed in East Central TX were identified and feces from four species out of those were quantified for the E. coli concentrations. No significant difference was found while comparing the E. coli concentration for each species between the genders. Sub-adult cattle feces had significantly higher E. coli concentrations than those from adult cattle. Growth and die-off rates of E. coli were measured at different temperatures (0°C, 10°C, 25°C, and 50°C) in creek water and moisture conditions (4%, 25% 56.5% and 83%; volumetric basis) in soil. E. coli concentrations in cattle and raccoon feces showed the highest survivability and growth at 20°C. There was no survival of E. coli from either species at 50°C after 24 h. E. coli in cattle and raccoon fecal samples exhibited greater growth at lower, nearly aerobic soil moisture content (25%) for all days compared to nearly anaerobic soil moisture content (83%).
关键词：Environmental Sciences and Engineering;Water Quality
