2011 +2015/16: Gormanston (Tasmania). E.coli, Lead, Colour, Iron, pH, Temperature, Turbidity

BOIL WATER ALERT

Gormanstone (Tasmania) – E.coli

September 27 2015: Gormanston (Tasmania) Mongomery St – E.coli 2 MPN100/mL

October 6 2015: Gormanston (Tasmania) Mongomery St – E.coli 3.1 MPN100/mL

November 3 2015: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

November 10 2015: Gormanston (Tasmania) Mongomery St – E.coli 1.5 MPN100/mL

November 24 2015: Gormanston (Tasmania) Mongomery St – E.coli 2.6 MPN100/mL

December 8 2015: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

December 29 2015: Gormanston (Tasmania) Mongomery St – E.coli 2 MPN100/mL

January 5 2016: Gormanston (Tasmania) Mongomery St – E.coli 2 MPN100/mL

January 12 2016: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

January 19 2016: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

January 21 2016: Gormanston (Tasmania) Mongomery St – E.coli 1.5 MPN100/mL

January 27 2016: Gormanston (Tasmania) Mongomery St – E.coli 2 MPN100/mL

February 2 2016: Gormanston (Tasmania) Lyell Hwy – E.coli 1 MPN100/mL

February 2 2016: Gormanston (Tasmania) Mongomery St – E.coli 6.3 MPN100/mL

February 2 2016: Gormanston (Tasmania) Mongomery St – E.coli 5.2 MPN100/mL

February 9 2016: Gormanston (Tasmania) Lyell Hwy – E.coli 6.5 MPN100/mL

February 9 2016: Gormanston (Tasmania) Mongomery St – E.coli 7.5 MPN100/mL

February 23 2016: Gormanston (Tasmania) Mongomery St – E.coli 3.1 MPN100/mL

March 1 2016: Gormanston (Tasmania) Mongomery St – E.coli 8.5 MPN100/mL

March 8 2016: Gormanston (Tasmania) Mongomery St – E.coli 4.1 MPN100/mL

March 15 2016: Gormanston (Tasmania) Mongomery St – E.coli 9.7 MPN100/mL

March 30 2016: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

April 5 2016: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

May 3 2016: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

May 17 2016: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

May 24 2016: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

June 28 2016: Gormanston (Tasmania) Mongomery St – E.coli 1 MPN100/mL

Escherichia coli should not be detected in any 100 mL sample of drinking water. If detected
in drinking water, immediate action should be taken including investigation of potential
sources of faecal contamination.

“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

Gormanston (Tasmania) – Lead

Lead has also breached ADWG’s at Queenstown and Gormanston in south west Tasmania. Breaches occurred three times in Gormanston in 2011 (highest reading 0.0295mg/L) and twice in Queenstown (highest reading 0.0.0118mg/L). In 2009-11, the following Tasmanian communities also had lead readings above the ADWG, Whitemark 0.017mg/L, Pioneer 0.015mg/L & 0.0109mg/L and Avoca 0.0106mg/L.

May 4 2016: Gormanston (Tasmania) – Lead 14.3ug/L

Based on health considerations, the concentration of lead in drinking water should not
exceed 0.01 mg/L.

“… Lead can be present in drinking water as a result of dissolution from natural sources, or from household plumbing systems containing lead. These may include lead in pipes, or in solder used to seal joints. The amount of lead dissolved will depend on a number of factors including pH, water hardness and the standing time of the water.

Lead is the most common of the heavy metals and is mined widely throughout the world. It is used in the production of lead acid batteries, solder, alloys, cable sheathing, paint pigments, rust inhibitors, ammunition, glazes and plastic stabilisers. The organo-lead compounds tetramethyl and tetraethyl lead are used extensively as anti-knock and lubricating compounds in gasoline…

Lead can be absorbed by the body through inhalation, ingestion or placental transfer. In adults,
approximately 10% of ingested lead is absorbed but in children this figure can be 4 to 5 times higher. After absorption, the lead is distributed in soft tissue such as the kidney, liver, and bone marrow where it has a biological half-life in adults of less than 40 days, and in skeletal bone where it can persist for 20 to 30 years.

In humans, lead is a cumulative poison that can severely affect the central nervous system. Infants, fetuses and pregnant women are most susceptible. Placental transfer of lead occurs in humans as early as the 12th week of gestation and continues throughout development.

Many epidemiological studies have been carried out on the effects of lead exposure on the intellectual development of children. Although there are some conflicting results, on balance the studies demonstrate that exposure to lead can adversely affect intelligence.

These results are supported by experiments using young primates, where exposure to lead causes significant behavioural and learning difficulties of the same type as those observed in children.

Other adverse effects associated with exposure to high amounts of lead include kidney damage, interference with the production of red blood cells, and interference with the metabolism of calcium needed for bone formation…” ADWG 2011

Gormanston (Tasmania) – Colour

August 6 2015: Gormanston (Tasmania) – Colour Apparent 17 PCU

December 1 2015: Gormanston (Tasmania) – Colour Apparent 38 PCU

January 19 2016: Gormanston (Tasmania) – Colour Apparent 187 PCU

April 19 2016: Gormanston (Tasmania) – Colour Apparent 120 PCU

Based on aesthetic considerations, true colour in drinking water should not exceed 15 HU.

“… Colour is generally related to organic content, and while colour derived from natural sources such as humic and fulvic acids is not a health consideration, chlorination of such water can produce a variety of chlorinated organic compounds as by-products (see Section 6.3.2 on disinfection by-products). If the colour is high at the time of disinfection, then the water should be checked for disinfection by-products. It should be noted, however, that low colour at the time of disinfection does not necessarily mean that the concentration of disinfection by-products will be low…

Gormanston – Tasmania – Iron

january 19 2016: Gormanston (Tasmania) – Iron 13700ug/L

February 2 2016: Gormanston (Tasmania) – Iron 4390ug/L

April 4 2016: Gormanston (Tasmania) – Iron 3020ug/L

April 19 2016: Gormanston (Tasmania) – Iron (dissolved) 380ug/L

May 4 2016: Gormanston (Tasmania) – Iron 4900ug/L

May 11 2016: Gormanston (Tasmania) – Iron 755ug/L

Based on aesthetic considerations (precipitation of iron from solution and taste),
the concentration of iron in drinking water should not exceed 0.3 mg/L.
No health-based guideline value has been set for iron.

Iron has a taste threshold of about 0.3 mg/L in water, and becomes objectionable above 3 mg/L. High iron concentrations give water an undesirable rust-brown appearance and can cause staining of laundry and plumbing fittings, fouling of ion-exchange softeners, and blockages in irrigation systems. Growths of iron bacteria, which concentrate iron, may cause taste and odour problems and lead to pipe restrictions, blockages and corrosion. ADWG 2011

Gormanston (Tasmania) – pH (acidic)

Average pH: 2015 July-2016 June: 5.789 pH units

Based on the need to reduce corrosion and encrustation in pipes and fittings, the pH of
drinking water should be between 6.5 and 8.5.

New concrete tanks and cement-mortar lined pipes can significantly increase pH and
a value up to 9.2 may be tolerated, provided monitoring indicates no deterioration in
microbiological quality.

pH is a measure of the hydrogen ion concentration of water. It is measured on a logarithmic scale from 0 to 14. A pH of 7 is neutral, greater than 7 is alkaline, and less than 7 is acidic.

One of the major objectives in controlling pH is to minimise corrosion and encrustation in pipes and fittings. Corrosion can be reduced by the formation of a protective layer of calcium carbonate on the inside of the pipe or fitting, and the formation of this layer is affected by pH, temperature, the availability of calcium (hardness) and carbon dioxide. If the water is too alkaline (above pH 8.5), the rapid deposition and build-up of calcium carbonate that can result may eventually block the pipe.

When pH is below 6.5 or above 11, the water may corrode plumbing fittings and pipes. This, however, will depend on other factors such as the material used, the concentration and type of ions in solution, the availability of oxygen, and the water temperature. Under some conditions, particularly in the presence of strong oxidising agents such as chlorine, water with a pH between 6.5 and 7 can be quite corrosive.

Chlorine disinfection efficiency is impaired above pH 8.0, although the optimum pH for monochloramine disinfectant formation is between 8.0 and 8.4. In chloraminated supplies chlorine can react with ammonia to form odorous nitrogen trichloride below pH 7.

Chlorination of water supplies can decrease the pH, while it can be significantly raised by lime leached from new concrete tanks or from pipes lined with asbestos cement or cement mortar. Values of pH above 9.5 can cause a bitter taste in drinking water. (ADWG 2011)

Gormanston – Tasmania – Temperature

January 27 2016: Gormanston (Tasmania) – Temperature 22.2C

GUIDELINE

“No guideline is set due to the impracticality of controlling water temperature.
Drinking water temperatures above 20°C may result in an increase in the number of
complaints.

Temperature is primarily an aesthetic criterion for drinking water. Generally, cool water is more palatable than warm or cold water. In general, consumers will react to a change in water temperature. Complaints are most frequent when the temperature suddenly increases.

The turbidity and colour of filtered water may be indirectly affected by temperature, as low water temperatures tend to decrease the efficiency of water treatment processes by, for instance, affecting floc formation rates and sedimentation efficiency.

Chemical reaction rates increase with temperature, and this can lead to greater corrosion of pipes and fittings in closed systems. Scale formation in hard waters will also be greater at higher temperatures…

Water temperatures in major Australian reticulated supplies range from 10°C to 30°C. In some long, above-ground pipelines, water temperatures up to 45°C may be experienced…

The effectiveness of chlorine as a disinfectant is influenced by the temperature of the water being dosed. Generally higher temperatures result in more effective disinfection at a particular chlorine dose, but this may be counterbalanced by a more rapid loss of chlorine to the atmosphere (AWWA 1990).

Gormanston – Tasmania – Turbidity

December 16 2015: Gormanston (Tasmania) – Turbidity 6.49 NTU

January 19 2016: Gormanston (Tasmania) – Turbidity 12.7 NTU

January 27 2016: Gormanston (Tasmania) – Turbidity 20.5 NTU

February 2 2016: Gormanston (Tasmania) – Turbidity 5.74 NTU

February 2 2016: Gormanston (Tasmania) – Turbidity 7.08 NTU

February 9 2016: Gormanston (Tasmania) – Turbidity 7.95 NTU

February 23 2016: Gormanston (Tasmania) – Turbidity 27.5 NTU

March 1 2016: Gormanston (Tasmania) – Turbidity 50.3 NTU

March 8 2016: Gormanston (Tasmania) – Turbidity 40.1 NTU

March 10 2016: Gormanston (Tasmania) – Turbidity 48.7 NTU

March 10 2016: Gormanston (Tasmania) – Turbidity 8.33 NTU

March 30 2016: Gormanston (Tasmania) – Turbidity 11 NTU

April 12 2016: Gormanston (Tasmania) – Turbidity 10.5 NTU

April 19 2016: Gormanston (Tasmania) – Turbidity 6.52 NTU

April 26 2016: Gormanston (Tasmania) – Turbidity 22.9 NTU

May 3 2016: Gormanston (Tasmania) – Turbidity 128 NTU

May 4 2016: Gormanston (Tasmania) – Turbidity 176 NTU

May 10 2016: Gormanston (Tasmania) – Turbidity 55.1 NTU

May 11 2016: Gormanston (Tasmania) – Turbidity 51.2 NTU

 

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.