12 March 2018 – Little Mountain (Queensland) – E.coli
Incident Description: There was an E. coli detection from a routine sample taken on 12/3/2018 at Raintree Blvd, Little Mountain from sample tap CL12DS. The result was 1mpn/100ml.
Corrective & Preventative Actions: Localised reactive flushing of the supply main and the affected sample tap. Sampling observations were reviewed along with weather conditions on the day of the detection. It was identified that the sample tap is located under tree foliage and it had been raining prior to the sample being taken. A review of the systems gave no reason to suggest that network integrity had been compromised at the time of sampling.
Follow up sample results: A follow up sample was taken on the same day and returned a result of <1mpn/100ml.
“Coliforms are Gram-negative, non-spore-forming, rod-shaped bacteria that are capable of aerobic and facultative anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are found in large numbers in the faeces of humans and other warm-blooded animals, but many species also occur in the environment.
Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG 2011