Delivery of microbial indicator organisms to coastal waters from catchment sources

Abstract

The introduction of ultraviolet disinfection of sewage effluent in Jersey has served to focus attention on other sources of faecal pollution responsible for subsequent compliance failures in coastal water quality in St Aubin's Bay. Studies of microbial concentrations (total coliforms, faecal coliforms and faecal streptococci) in streams draining to the bay showed concentrations to be elevated by an order of magnitude or more following rainfall. Detailed monitoring of indicator organisms during hydrograph events showed rapid increases in concentration with flow associated with the rising limb of the hydrograph and transport of suspended solids. Microbial budget estimates suggested that between 42 and 97% of microbial delivery was associated with high flows, which account for just 20% of the total discharge. Budgets also revealed the relative importance of different catchment inputs, revealing the low bacterial input associated with UV treated effluent which provided 48% of the total volume discharged to the bay. Implications for water quality standards are discussed with reference to catchment management planning.

Development of a risk-based index for source water protection planning, which supports the reduction of pathogens from agricultural activity entering water resources

“…Distributed or unconfined sources include faeces deposited by pastured animals and wildlife, together with recognised organic amendments, such as manure and sewage biosolids. Partially confined sources include animal feedlots, animal housing and manure storages, and on-site wastewater treatment systems (Wyer et al, 1996;Jones and Obiri-Danso, 1999). Many sources are subject to some level of control depending on decisions of the farmer.…”

Quantitative catchment profiling to apportion faecal indicator organism budgets for the Ribble system, the UK's sentinel drainage basin for Water Framework Directive research

“…Routine samples were taken at two to three day intervals to characterise base flow conditions. Opportunistic sampling in response to rainfall was implemented to target riverine sampling during hydrograph events, when faecal indicator organisms have been observed to increase (Crowther et al, 2002(Crowther et al, , 2003McDonald and Kay, 1981;Wilkinson et al, 2006;Wyer et al, 1996Wyer et al, , 1998. Sampling under these conditions also included stormwater surcharged FE flows and intermittent sewage effluent discharges from storm tank overflows (STOs) and CSOs.…”

“…Hourly flow records for the riverine sites were separated into base flow and rainfall-induced high flow hydrograph events (Wyer et al, 1996) using a combination of bespoke computer programmes (Pascal) and visual inspection of individual hydrograph events.…”

Respective contributions of point and non-point sources of E. coli and enterococci in a large urbanized watershed (the Seine river, France)

“…Fecal pollution brought to the rivers through surface runoff and soil leaching represents the non-point source; its origin can be the wild animals and grazing livestock feces and also cattle manure spread on cultivated areas (Atwill et al, 2002;Collins and Rutherford, 2004;Tyrrel and Quinton, 2003). Quantification of fecal contamination of rivers through land sources is relatively difficult and consequently there are only a few publications on this subject (Wyer et al, 1996(Wyer et al, , 1997Avery et al, 2004).…”