Fecal bacteria in the waters of an upland area in Derbyshire, England: The influence of agricultural land use

Long-term data on the dynamics of sanitary indicator bacteria in fresh waters is limited. This paper provides a data record of fluctuations in fecal bacterial concentrations in the waters of an upland area of northern England that can be examined in relation to agricultural land use practices and standards for contact recreation. Concentrations of fecal coliforms (FCs) were monitored in the waters of semi-improved sheep pasture on the edge of a limestone karst system in north Derbyshire, England for a 21-mo period. Data were obtained for three small streams and six water inflows to streams, comprising the end points of shallow subsurface tile drainage networks and natural, semi-permanent, channelized overland flows. All sites showed significant contamination by fecal indicator bacteria. A consistent pattern of seasonal FC concentration change was observed at all sites, with concentrations generally highest during the summer and lowest during the winter. This may be explained by land use factors, including higher summer sheep stocking densities and the application of farmyard manure and sewage sludge. Correlations between changes in bacterial concentration at inflow sites and downstream changes in streamwater concentration were generally highly significant, providing strong empirical evidence for the assumed causal relationship between inflow and streamwater quality. The degree of fecal bacterial contamination of the streams, particularly during summer months, may constitute a real health risk to recreational cavers using parts of the limestone karst system into which the streams drain.