The effect of a new sewage treatment plant on faecal indicator numbers, campylobacters and bathing water compliance in Morecambe Bay

Abstract

Until recently, sewage from Morecambe was macerated, but otherwise untreated, and discharged at high water via a short outfall pipe into Morecambe Bay adjacent to a recognized bathing water. In March 1997, a new biological sewage treatment plant came on‐line and the effluent was discharged via a longer outfall pipe into the Bay south of Heysham. The effect of the new sewage treatment on the quality of the bathing waters was monitored by testing sea water collected from the three EU designated bathing waters on Morecambe Bay: Morecambe North, Morecambe South and Heysham. After sewage treatment came on‐line, the numbers of faecal coliforms and faecal streptococci were lower at Morecambe North and Morecambe South but higher at Heysham. Although the changes in numbers were not always statistically significant, they were sufficient to affect compliance with the EU Bathing Water Directive Imperative (mandatory) standards. Compliance improved markedly at Morecambe North and South but declined at Heysham, the closest bathing site to the new outfall. Numbers of thermophilic campylobacters were similar in both years, which is suggestive of their sources being different from those of the indicator bacteria. Campylobacter lari and urease‐positive thermophilic campylobacters (UPTC) were the only species of Campylobacter isolated from Morecambe's bathing waters. Very low numbers of Salmonella were found, with Salm. arizonae the only species isolated.

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

“…4). Counts in foreshore sand were much higher than counts in water, a pattern seen in other studies (30,44,46). In water, E. coli counts were consistently higher in samples from a depth of 45 cm than in those from 90 cm, with counts decreasing in samples collected further from shore, a pattern that has also been shown in other lakes (50).…”

“…Bathing activities have been considered to be a potential source of E. coli through the shedding of indicator bacteria, resuspension of contaminated sediments, or transport of bacteria from the sand to the water (44,48). Surveys at 63rd Street Beach, however, found that there was no correlation between the number of bathers and bacterial counts in the sand or water.…”

“…When sampling began in early April, E. coli counts in sand were already elevated, an occurrence unlikely to be the result of early-season multiplication, given the high counts (April mean, 2,277 CFU/100 ml) and early-season temperatures (April mean, 4.9°C). Research has shown that fecal indicators can persist in sand throughout the year with little variation in counts (44); survival in cold temperatures is typically high for indicator bacteria such as E. coli (54), which provides an early spring source of E. coli to the nearshore water. With the onset of warm temperatures, E. coli counts increased dramatically between April and May, the period with the greatest increase in average air and water temperatures over the sampling period.…”

Campylobacter in the environment: A major threat to public health

“…C. lari and urease-positive thermotolerant campylobacters (UPTC) were the only species detected at Morecambe Bay, while in River Lune, C. jejuni, C. coli, C. lari and UPTC were detected. The sources of C. lari in the former site was found to be dense populations of gulls, knots and oystercatchers, whereas sewage effluents, runoff from agricultural land and dense populations of ducks were the source of C. jejuni, C. coli, C. lari and UPTC at the latter site [19,41]. Contamination of the River Leck (Netherlands) with Campylobacter sp.…”

“…Campylobacter species were readily detected from fecally contaminated drinking water [12], rivers [13,14], lakes [15], ponds [16], drainage channels [14], ground water [17,18], marine waters [19], rain-related and agricultural runoff [16], additionally, sewage effluents contain abundant concentrations of Campylobacter species [20,21]. Drinking untreated water plays an important role in Campylobacter epidemiology as it remains one of the most significant sources of campylobacteriosis worldwide [12].…”