Characterization of sources and loadings of fecal pollutants using microbial source tracking assays in urban and rural areas of the Grand River Watershed, Southwestern Ontario.

Sources of fecal water pollution were assessed in the Grand River and two of its tributaries (Ontario, Canada) using total and host-specific (human and bovine) Bacteroidales genetic markers in conjunction with reference information, such as land use and weather. In-stream levels of the markers and culturable Escherichia coli were also monitored during multiple rain events to gain information on fecal loadings to catchment from diffuse sources. Elevated human-specific marker levels were accurately identified in river water impacted by a municipal wastewater treatment plant (WWTP) effluent and at a downstream site in the Grand River.

Quantitative identification of fecal water pollution sources by TaqMan real-time PCR assays using Bacteroidales 16S rRNA genetic markers.

PCR-based analysis of Bacteroidales 16S rRNA genes has emerged as a promising tool to identify sources of fecal water pollution. In this study, three TaqMan real-time PCR assays (BacGeneral, BacHuman, and BacBovine) were developed and evaluated for their ability to quantitatively detect general (total), human-specific, and bovine-specific Bacteroidales 16S rRNA genetic markers. The detection sensitivity was determined to be 6.

Repetitive element (REP)-polymerase chain reaction (PCR) analysis of Escherichia coli isolates from recreational waters of southeastern Lake Huron.

Repetitive element-polymerase chain reaction (REP-PCR) DNA fingerprinting and library-based microbial source tracking (MST) methods were utilized to investigate the potential sources of Escherichia coli pollution in recreational waters of southeastern Lake Huron. In addition to traditional sources such as humans, agriculture, and wildlife, environmentally persistent E. coli isolates were included in the identification library as a separate library unit consisting of the E.

Genetic relatedness of Escherichia coli isolates in interstitial water from a Lake Huron (Canada) beach.

Research was undertaken to characterize Escherichia coli isolates in interstitial water samples of a sandy beach on the southeastern shore of Lake Huron, Ontario, Canada. A survey of the beach area revealed the highest abundance of E. coli in interstitial water of the foreshore beach sand next to the swash zone.

Influence of temperature on Cryptosporidium parvum oocyst infectivity in river water samples as detected by tissue culture assay.

Cryptosporidium parvum oocysts were stored in 1-ml aliquots of filtered river water at -20, 4, 10, and 21-23 C in the dark. Oocysts were also added to filter-sterilized river water samples and stored at 21-23 C. The infectivity of oocysts stored under different conditions was assayed at weekly intervals through infection of human adenocarcinoma ileocecal (HCT-8) cell monolayers.

Efficacy of common laboratory disinfectants on the infectivity of Cryptosporidium parvum oocysts in cell culture.

Nine liquid disinfectants were tested for their ability to reduce infectivity of Cryptosporidium parvum oocysts in cell culture. A 4-min exposure to 6% hydrogen peroxide and a 13-min exposure to ammonium hydroxide-amended windshield washer fluid reduced infectivity 1,000-fold. Other disinfectants tested (70% ethanol, 37% methanol, 6% sodium hypochlorite, 70% isopropanol, and three commercial disinfectants) did not reduce the infectivity after a 33-min exposure.