TY - JOUR
T1 - Tracing fecal pollution sources in karst groundwater by Bacteroidales genetic biomarkers, bacterial indicators, and environmental variables
AU - Zhang, Ya
AU - Kelly, Walton R.
AU - Panno, Samuel V.
AU - Liu, Wen Tso
N1 - Funding Information:
This work was funded by the Midwest Technology Assistance Center (MTAC), which supports U.S. Environmental Protection Agency's Strategic Plan Goal 2 of Clean and Safe Water, Objective 2.1: Protect Human and Sub-Health Objective 2.1.1: Water Safe to Drink under Grand No. USEPA EM-83444901. We are especially grateful for the assistance of local officials in identifying contaminated sites and securing permission to sample. The authors thank Peiying Hong for providing reference DNAs and comments on the research project. Chemical analyses were done at the Illinois State Water Survey Public Service laboratory in Champaign, IL, and bacterial indicator analyses were done at the Illinois Department of Agriculture Animal Disease Laboratory in Centralia, IL, and the Wisconsin State Laboratory of Hygiene in Madison, WI.
PY - 2014/8/15
Y1 - 2014/8/15
N2 - Fecal contamination in Midwestern karst regions was evaluated by simultaneously measuring traditional bacterial indicators (coliforms and Escherichia coli), Bacteroidales-based biomarkers, and environmental variables. Water samples from springs and wells were collected from karst regions in Illinois (IL), Wisconsin (WI), Kentucky (KY), and Missouri (MO). Quantitative PCR (Q-PCR) with seven primer sets targeting different members of Bacteroidales was used to determine the origin of fecal contamination (i.e., from human waste, livestock waste, or both). Most samples were contaminated by both human and animal waste, with a few samples showing pollution solely by one or the other. Spring water tended to have higher levels of contamination than well water, and higher concentrations of fecal biomarkers were detected in urban springs compared to rural spring systems. However, there were discrepancies on contamination profile determined by Bacteroidales-based biomarkers and by traditional bacterial indicators. Among all the environmental parameters examined, E. coli, sulfate, total dissolved solids (TDS), and silicon were significantly correlated (p<0.05) with the level of Bacteroidales-based fecal indicators. A rapid screening method using total nitrogen (TN) and chloride (Cl-) concentrations to determine fecal contamination was shown to be effective and correlated well with Bacteroidales-based MST. The results suggest that human and livestock feces co-contaminated a large portion of karst groundwater systems in Midwestern regions, and the inclusion of traditional bacterial indicators, environmental variables, and Bacteroidales-based MST is an effective approach for identifying fecal contamination in karst regions. •Bacteroidales-based biomarkers are used for tracking fecal contamination in karst regions.
AB - Fecal contamination in Midwestern karst regions was evaluated by simultaneously measuring traditional bacterial indicators (coliforms and Escherichia coli), Bacteroidales-based biomarkers, and environmental variables. Water samples from springs and wells were collected from karst regions in Illinois (IL), Wisconsin (WI), Kentucky (KY), and Missouri (MO). Quantitative PCR (Q-PCR) with seven primer sets targeting different members of Bacteroidales was used to determine the origin of fecal contamination (i.e., from human waste, livestock waste, or both). Most samples were contaminated by both human and animal waste, with a few samples showing pollution solely by one or the other. Spring water tended to have higher levels of contamination than well water, and higher concentrations of fecal biomarkers were detected in urban springs compared to rural spring systems. However, there were discrepancies on contamination profile determined by Bacteroidales-based biomarkers and by traditional bacterial indicators. Among all the environmental parameters examined, E. coli, sulfate, total dissolved solids (TDS), and silicon were significantly correlated (p<0.05) with the level of Bacteroidales-based fecal indicators. A rapid screening method using total nitrogen (TN) and chloride (Cl-) concentrations to determine fecal contamination was shown to be effective and correlated well with Bacteroidales-based MST. The results suggest that human and livestock feces co-contaminated a large portion of karst groundwater systems in Midwestern regions, and the inclusion of traditional bacterial indicators, environmental variables, and Bacteroidales-based MST is an effective approach for identifying fecal contamination in karst regions. •Bacteroidales-based biomarkers are used for tracking fecal contamination in karst regions.
KW - Bacterial indicators
KW - Bacteroidales-based microbial source tracking
KW - Environmental variables
KW - Fecal contamination
KW - Karst
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U2 - 10.1016/j.scitotenv.2014.05.086
DO - 10.1016/j.scitotenv.2014.05.086
M3 - Article
C2 - 24922611
AN - SCOPUS:84902118088
SN - 0048-9697
VL - 490
SP - 1082
EP - 1090
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -