21/6/20 – Boisdale (Victoria) – E.coli

21/6/20: Boisdale (Vic) – E.coli.
Boisdale drinking water reticulation sample point. Detection of E. Coli at a concentration of 1 org/100mL in routine drinking water sampling program. Resampling of the Boisdale reticulation system including the water storage tanks and all available sampling points. Asset inspections and risk assessment of the Boisdale water system. Spot dosing of the Boisdale water tanks and flushing of the reticulation system
Two repeat sampling events of the Boisdale reticulation 24 hrs apart.Minor repairs to the one
water storage tank.
All water quality indicators including residual free chlorine were within our CCPs for system
protection and immediate risk determined to be very low

“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