Non-point source pollution: Determination of replication versus persistence of Escherichia coli in surface water and sediments with correlation of levels to readily measurable environmental parameters

Abstract

Racine, Wisconsin, located on Lake Michigan, experiences frequent recreational water quality advisories in the absence of any identifiable point source of pollution. This research examines the environmental distribution of Escherichia coli in conjunction with the assessment of additional parameters (rainfall, turbidity, wave height, wind direction, wind speed and algal presence) in order to determine the most probable factors that influence E. coli levels in surface waters. Densities of E. coli were highest in core samples taken from foreshore sands, often exceeding an order of magnitude greater than those collected from submerged sands and water. Simple regression and multivariate analyses conducted on supplementary environmental data indicate that the previous day's E. coli concentration in conjunction with wave height is significantly predictive for present-time E. coli concentration. Genetic fingerprinting using repetitive element anchored PCR and cellular fatty acid analysis were employed to assess the presence of clonal isolates which indicate replication from a common parent cell. There were relatively few occurrences of clonal patterns in isolates collected from water, foreshore and submerged sands, suggesting that accumulation of E. coli, rather than environmental replication, was occurring in this system. Non-point source pollution, namely transport of accumulated E. coli from foreshore sands to surface waters via wave action, was found to be a major contributor to poor recreational water quality at the Lake Michigan beaches involved in this study.

Microbial Source Tracking

“…It is necessary to discard these unmatched isolates; identifying them based on similarity to, rather than identity with, known isolates results in incorrect classifications. This observation fits with evidence that environmentally-adapted, rather than fecal, genotypes of FIB dominate extra-intestinal habitats (87,107,128).Library-independent, culture-dependent methods.…”

Indigenous Microbiota and Habitat Influence Escherichia coli Survival More than Sunlight in Simulated Aquatic Environments

“…Relatively low rates of protozoan grazing have been reported for the sediments (68)(69)(70)(71)(72)(73)(74)(75), providing a possible mechanism for FIB persistence in such habitats. Maintenance of elevated FIB concentrations in sediments is of practical importance and has public health implications, as previous studies indicated that resuspension can lead to increased bacterial concentrations in the water column (76)(77)(78)(79)(80)(81)(82). A recent study (43), which manipulated indigenous microbiota by adding kanamycin to reduce competition from prokaryotic community, found that inclusion of the antibiotic extended E. coli survival in the river water and sediments, corroborating our results.…”

Fecal indicator organism density in beach sands: Impact of sediment grain size, uniformity, and hydrologic factors on surface water loading

“…Previous studies conducted in Racine, Wisconsin indicated that the foreshore beach sands served as a reservoir for the fecal indicator bacteria E. coli (Kinzelman et al 2004b) and more recent studies also suggest that beach sands may harbor pathogens, hence a risk of illness upon contact (Heaney et al 2009, Whitman et al 2009). Densities of E. coli in foreshore beach sands were significantly greater than that of submerged sands and back shore sands located within the same beach transects (Kinzelman et al, 2004b, Kinzelman 2005. High E. coli densities could be explained, in part, by the constant accumulation of fecal material deposited by the large population of resident gulls (Kinzelman et al, 2004b).…”