Foreshore Sand as a Source of Escherichia coli in Nearshore Water of a Lake Michigan Beach

Abstract

Swimming advisories due to excessive Escherichia coli concentrations are common at 63rd Street Beach, Chicago, Ill. An intensive study was undertaken to characterize the source and fate of E. coli in beach water and sand at the beach. From April through September 2000, water and sand samples were collected daily or twice daily at two depths on three consecutive days per week (water samples, n ‫؍‬ 1,747; sand samples, n ‫؍‬ 858); hydrometeorological conditions and bird and bather distributions were also recorded. E. coli concentrations in sand and water were significantly correlated, with the highest concentration being found in foreshore sand, followed by those in submerged sediment and water of increasing depth. Gull contributions to E. coli densities in sand and water were most apparent on the day following gull activity in a given area. E. coli recolonized newly placed foreshore sand within 2 weeks. Analysis of variance, correlation, cluster analyses, concentration gradients, temporal-spatial distribution, demographic patterns, and DNA fingerprinting suggest that E. coli may be able to sustain population density in temperate beach sand during summer months without external inputs. This research presents evidence that foreshore beach sand (i) plays a major role in bacterial lake water quality, (ii) is an important non-point source of E. coli to lake water rather than a net sink, (iii) may be environmentally, and perhaps hygienically, problematic, and (iv) is possibly capable of supporting an autochthonous, high density of indicator bacteria for sustained periods, independent of lake, human, or animal input.

Beach Sand and Sediments are Temporal Sinks and Sources of Escherichia coli in Lake Superior

“…In contrast, we and others have previously reported the survival of E. coli strains over the winter in riverine soils in Minnesota (6) and in foreshore (9) and backshore sands (20) in Lake Michigan. Ice on the DBC beach disappeared after mid-April 2005, allowing direct contact of lake water to beach sand by wave action.…”

“…Similarly, E. coli counts did not significantly vary according to the distance from shoreline in the May 2005 samples. While Whitman and Nevers (9) reported that E. coli concentrations decreased as the distance from the shoreline increased, they examined much longer distances than were used in our study.…”

“…Waterfowl may represent a major potential source of E. coli on beaches (9). However, since some waterfowl, such as Canada geese (Branta canadensis) are migratory, their contribution to water-and beach-borne E. coli may change seasonally.…”

“…However, since some waterfowl, such as Canada geese (Branta canadensis) are migratory, their contribution to water-and beach-borne E. coli may change seasonally. Sand may also serve as a reservoir for E. coli and fecal coliform bacteria (9,(20)(21)(22)(23). Whitman and Nevers (9) and Alm et al (22) reported that E. coli strains rapidly colonized, grew, and maintained their population in beach sand.…”

Influences of natural and anthropogenic factors on surface and groundwater quality in rural and urban areas

“…An adequate faecal indicator does not reproduce outside the animal host. E. coli and enterococci grow, survive and establish their populations in natural environments such as freshwater lakes and streams (Byappanahalli et al 2003;Power et al 2005), algal wrack (Olapade et al 2006;Whitman and Nevers 2003), beach sand (Byappanahalli, Whitman, Shively, Ting, et al 2006;Whitman et al 2005), soils and sediments (Anderson et al 2005;Byappanahalli and Fujioka 2004;Byappanahalli, Whitman, Shively, Sadowsky, et al 2006;Fujioka et al 1999;Ishii et al 2006;Solo-Gabriele et al 2000;Whitman et al 2005), and plant cavities (Whitman et al 2005).…”