Microbial Source Tracking Project - Cuckmere, Sussex

High nutrient inputs into water bodies, such as reservoirs, can result in an increase in algal blooms and costs associated with water treatment. Cyanobacteria (often known as blue-green algae) can be harmful to human health due to the production of harmful toxins. Legislative requirements, the need to predict risk to human health, and the implications of source on the selection of appropriate remediation measures, have led to the development of the field of microbial source tracking (MST).

MST encompasses techniques that aim to distinguish source(s) of faecal contamination in surface and ground waters. One relatively simple, low-cost and effective technique, successfully used to discriminate human from non-human faecal contamination, involves the detection and enumeration of bacteriophages (viruses) capable of infecting anaerobic bacteria (Bacteroides spp.) present in human waste. Certain strains of Bacteroides spp. that are demonstrably restricted to human faeces have been isolated from different geographical regions (including strain GB124 in Southeast England), and have been used successfully to distinguish human faecal contamination of surface waters from non-human sources.

Arlington reservoir in the River Cuckmere catchment in Sussex is at risk from increased levels of cyanobacteria posing a potential risk to users. The problem sources of faecal contamination are currently ambiguous and it is necessary to distinguish between human and non-human sources. This study aimed to determine, if bacteriophages infecting a human-specific host strain (GB124) could distinguish human-faecal inputs from small scale inputs such as those expected from individual septic tanks and small feeder streams.