Identification of fecal pollution sources of karst waters by a combination of Bacteroidales genetic marker, bacterial indicators, and environmental variables

fecal contamination;karst;Bacteroidales-based microbial source tracking;bacterial indicators;springs;wells;environmental variables

Zhang, Ya ; Liu ; Wen-Tso

关键词: fecal contamination;    karst;    Bacteroidales-based microbial source tracking;    bacterial indicators;    springs;    wells;    environmental variables;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/34261/Zhang_Ya.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Fecal contamination in Midwestern karst regions was evaluated by a combination of Bacteroidales-based microbial source tracking (MST), traditional bacterial indicators, and environmental variables. Water samples from springs and wells were collected from Illinois, Wisconsin, Kentucky and Missouri quarterly. Quantitative PCR with seven primer sets targeting different members of Bacteroidales was used to discriminate human and livestock fecal pollution. The results suggested that contamination by both human and animal waste was the dominant type of pollution among all samples, and only a few samples showed pollution solely by human or animal. Furthermore, spring water tended to be more contaminated than well water, and urban spring systems were detected with a higher number of fecal biomarkers than rural spring systems. However, correlation between traditional bacterial indicators and fecal contamination determined by Bacteroidales-based MST was weak. Among all the environmental parameters examined, Escherichia coli, Cl-, and ORP were significantly correlated (p < 0.05) with level of Bacteroidales fecal biomarkers. Well samples were affected by ORP and Cl- the most, and samples from springs were influenced by all three parameters. The results illustrated that a large portion of karst groundwater systems in Midwestern regions was co-contaminated with human and livestock feces. The inclusion of traditional bacterial indicators and a variety of environmental variables in addition to Bacteroidales-based MST provided an effective toolbox for identifying fecal contamination in karst regions.