Ingham (Queensland) – E.coli

No E. Coli has been detected in the water samples since 1995, with 3 instances occurring in March 1995. A summary of the findings is below: The bacterial testing for E. Coli in the reticulated system for scheme 1 shows that the water supply has meet ADWG 99.54% between 1982 to 2011 with 2188 samples being taken. It is  also evident that no breaches of the guideline have occurred since 1995.

“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

Ingham (Queensland) – Fluoride

The raw water sources for Scheme 1 have low presence of fluoride, but an abnormal result was recorded for the  Herbert River in 2006. It is thought that this is operator error when entering the sampling data into a spreadsheet. The result showed a reading of 9.1 mg/L of fluoride in the raw water sample which is much higher than the average of 0.4 mg/L in the 28 samples that are available for the river. Fluoride levels in treated water  are well below the ADWG. Reticulated water also shows low levels of fluoride in the system

“Fluoride occurs naturally in seawater (1.4 mg/L), soil (up to 300 parts per million) and air (from volcanic gases and industrial pollution). Naturally occurring fluoride concentrations in drinking water depend on the type of soil and rock through which the water drains. Generally, concentrations in surface water are relatively low (<0.1–0.5 mg/L), while water from deeper wells may have quite high concentrations (1–10 mg/L) if the rock formations are fluoride-rich.” 2011 ADWG. Health Guideline: 1.5mg/L

Ingham (Queensland) – Turbidity

2013/14: Ingham (Queensland) – Turbidity. 5NTU (max), 1NTU (av.)

2014/15: Ingham (Queensland) – Turbidity. 6NTU (max), 1.04NTU (av.)

Turbidity in the Herbert is quite high and increases during the wet season and has been designated as a backup  supply. As the Herbert source is not often used, the turbidity was a maximum of 18 NTU in the past 5 years.  Turbidity in the groundwater is usually <1.0 NTU and therefore is used as the primary supply. Prior to 1996 the  Herbert River was the only source water for Scheme 1 until the bore fields south of Ingham were constructed. A result of 8 NTU was recorded at Hunter Street on 14th July 2003. Operational controls are planned to ensure
raw water sources are selected based on turbidity QCP and CCP limits.

Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment
process to address identified risks from Cryptosporidium and Giardia, it is essential
that filtration is optimised and consequently the target for the turbidity of water leaving
individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with
chlorine unless a higher value can be validated in a specific context.

Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the
consumer’s tap.