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Hoyland Nether, United Kingdom

Watkins J.,CREH Analytical | Sartory D.P.,SWM Consulting
Letters in Applied Microbiology | Year: 2015

A modification of the UK reference and ISO 14189 TSCA medium for the enumeration of Clostridium perfringens from water coupled with a membrane filter transfer technique for testing for production of acid phosphatase was evaluated. The new tryptose cycloserine agar (TCA) medium, which lacks sodium metabisulphite but contains sodium pyruvate to improve recovery, allows the isolation and confirmation of Cl. perfringens within 18-24 h of sample processing. Data from a multilaboratory study analysed according to ISO 17994 showed that TCA was equivalent to TSCA for the enumeration of Cl. perfringens. The identification of acid phosphatase-negative isolates revealed a false-negative rate for the TCA method of 0·8%. The TCA membrane filter transfer procedure provides confirmed Cl. perfringens counts in half the time of the TSCA method and is simple to undertake. © 2014 The Society for Applied Microbiology. Source

Stapleton C.M.,Aberystwyth University | Kay D.,Aberystwyth University | Magill S.H.,Scottish Association for Marine Science | Wyer M.D.,Aberystwyth University | And 5 more authors.
Aquaculture Research | Year: 2011

Sanitary surveys of shellfish harvesting waters are now a routine component of regulatory monitoring. These provide a qualitative appraisal of potential pollutant sources impacting on shellfish microbial quality. The information provided by this type of screening level appraisal is very useful, but does not afford quantitative assessment of the different pollution sources and their complex dynamic relationships which result in a highly episodic flux of microbial parameters into shellfish harvesting waters. The potential fluxes derive from treated sewage and industrial effluents, intermittent discharges from the sewerage system and diffuse sources of pollution, principally from livestock farming areas, but also from urban surface water drainage. None of these sources are routinely monitored for the faecal indicator parameters used as compliance measures by regulators worldwide and almost no high-flow information is available with which to construct any quantitative flux estimates to provide a credible evidence base for the design of remediation strategies where there is a need to improve water quality within a harvesting area. This study was conducted at Loch Etive, near Oban, Scotland, UK. It applies an approach to Quantitative Microbial Source Apportionment developed to inform management and remediation of water quality at bathing water locations. The results suggested that, in this case study location, diffuse sources of microbial indicator organisms derived from livestock farming activities in catchments draining to the loch were the dominant high-flow contribution of bacterial loadings. This finding was unexpected by local managers who had perceived 'environmental' water quality as 'high quality' in this traditionally pristine area of west Scotland. The findings led to a series of recommendations for future management of Scottish shellfish harvesting waters directed at appropriate data acquisition, through a detailed sampling programme design, to acquire microbial flux data from all sources, particularly during high-flow event conditions. It was recommended that such data acquisition was essential to the design of any remediation strategies that need a credible evidence base directing appropriate investment in interventions designed to attenuate microbial flux from either the sewerage infrastructure and/or adjacent farming activities. The utility of this study could be further enhanced through microbial tracer studies to establish connectivity between the key hydrological inputs (both those studied here and potential sources outside of the lower basin) and the shellfish beds. © 2010 The Authors. Journal Compilation © 2010 Blackwell Publishing Ltd. Source

Wyer M.D.,Aberystwyth University | Kay D.,Aberystwyth University | Watkins J.,CREH Analytical | Davies C.,CREH Analytical | And 5 more authors.
Water Research | Year: 2010

Quantitative assessment of multiple sources to short-term variations in recreational water quality, as indexed by faecal indicator organism (FIO) concentrations, is becoming increasingly important with adoption of modern water quality standards and catchment-based water quality management requirements (e.g. the EU Water Framework Directive, Article 11 '. Programmes of Measures' and the US Clean Water Act, '. Total Maximum Daily Loads'). This paper describes a study combining microbial tracers, intensive FIO measurement, open channel hydrology and molecular microbial source tracking (MST) to enhance understanding of recreational water quality at Amroth in southwest Wales, UK. Microbial tracers were released from four stream inputs during a moderate hydrograph event. Tracers from two local streams impacted simultaneously with a period of maximum FIO concentrations at the near-shore compliance monitoring site. Connection between these inputs and this site were rapid (9-33. min). Water quality impairment from a more remote stream input followed, 12.85. h after tracer release, sustaining FIO concentrations above desired compliance levels. MST analysis showed dominance of ruminant Bacteroidales genetic markers, associated with agricultural pollution. This integration of tracers and MST offers additional information on the movement and individual sources causing water quality impairment. © 2010 Elsevier Ltd. Source

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