DO NOT CONSUME
Avoca (Tasmania) – Cadmium
October 2013: Avoca – Cadmium 2.2ug/, 4ug/L at Avoca in November 2011 – caused by flooding which washed cadmium from mining areas upstream into water supply.
14/6/16; Avoca (Tasmania) – Cadmium 2.3ug/L
Cadmium: ADWG Guideline. 0.002mg/L (2ug/L), The primary route of exposure of cadmium is via contaminated water or food. Fertiliser can be a source of excessive cadmium as can
rainwater tanks. It has been linked to cancer, lung disorders, kidney disease and autoimmune disease.
Australian Drinking Water Guideline (ADWG) Cadmium: 2ug/L
Avoca (Tasmania) – Lead
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.
November 2013: Avoca – Lead 59.9ug/L
Australian Drinking Water Guideline (ADWG) Lead: 10ug/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
Avoca (Tasmania) – Dichloroacetic Acid
August 8 2015 Avoca (Tasmania) – Dichoroacetic Acid 150ug/L
June 14 2016 Avoca (Tasmania) – Dichoroacetic Acid 200ug/L
June 22 2015 Avoca (Tasmania) – Dichoroacetic Acid 170ug/L
2016/17: Avoca (Tasmania) – Dichloroacetic Acid 130 ug/L
Avoca (Tasmania) – Trichloroacetic Acid
November 18 2015 Avoca (Tasmania) – Trichoroacetic Acid 160ug/L
June 14 2016 Avoca (Tasmania) – Trichoroacetic Acid 180ug/L
June 22 2015 Avoca (Tasmania) – Trichoroacetic Acid 180ug/L
2016/17: Avoca (Tasmania) – Trichloroacetic Acid 222 ug/L
Australian Guideline Level: Dichloroacetic Acid 0.100mg/L
“Chloroacetic acids are produced in drinking water as by-products of the reaction between chlorine and naturally occurring humic and fulvic acids. Concentrations reported overseas range up to 0.16mg/L and are typically about half the chloroform concentration. The chloroacetic acids are used commercially as reagents or intermediates in the preparation of a wide variety of chemicals. Monochloroacetic acid can be used as a pre-emergent herbicide, dichloroacetic acid as an ingredient in some pharmaceutical products, and trichloroacetic acid as a herbicide, soil sterilant and antiseptic.” Australian Drinking Water Guidelines – National Health and Medical Research Council
Avoca (Tasmania) – Aluminium
2013-14 (Average): Avoca – Aluminium 225.6ug/L
14/6/16: Avoca – Aluminium 1300ug/L
According to the ADWG, no health guideline has been adopted for Aluminium, but that the issue is still open to review. Aluminium can come from natural geological sources or from the use of aluminium salts as coagulants in water treatment plants. According to the ADWG “A well-operated water filtration plant (even using aluminium as a flocculant) can achieve aluminium concentrations in the finished water of less than 0.1 mg/L.
The most common form of aluminium in water treatment plants is Aluminium Sulfate (Alum). Alum can be supplied as a bulk liquid or in granular form. It is used at water treatment plants as a coagulant to remove turbidity, microorganisms, organic matter and inorganic chemicals. If water is particularly dirty an Alum dose of as high as 500mg/L could occur. There is also concern that other metals may also exist in refined alum.
While the ADWG mentions that there is considerable evidence that Aluminium is neurotoxic and can pass the gut barrier to accumulate in the blood, leading to a condition called encephalopathy (dialysis dementia) and that Aluminium has been associated with Parkinsonism dementia and amyotrophic lateral sclerosis, the NHMRC, whilst also acknowledging studies which have linked Aluminium with Alzheimer disease, has not granted Aluminium a NOEL (No Observable Effect Level) due to insufficient and contradictory data. Without a NOEL, a health guideline cannot be established. The NHMRC has also stated that if new information comes to hand, a health guideline may be established in the future.
In communication with Aluminium expert Dr Chris Exley (Professor in Bioinorganic Chemistry
The Birchall Centre, Lennard-Jones Laboratories, Keele University, Staffordshire UK) in March 2013 regarding high levels of Aluminium detected in the South Western Victorian town of Hamilton
“It is my opinion that any value above 0.5 mg/L is totally unacceptable and a potential health risk. Where such values are maintained over days, weeks or even months, as indeed is indicated by the data you sent to me, these represent a significant health risk to all consumers. While consumers may not experience any short term health effects the result of longer term exposure to elevated levels of aluminium in potable waters may be a significant increase in the body burden of aluminium in these individuals. This artificially increased body burden will not return to ‘normal’ levels when the Al content of the potable water returns to normal but will act as a new platform level from which the Al body burden will continue to increase with age.
Avoca – (Tasmania) – Colour
August 12 2015: Avoca – Colour 29 PCU
November 18 2015: Avoca – Colour 40 PCU
June 14 2016: Avoca – Colour 127 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…”
Australian Drinking Water Guidelines 2011
Avoca – Tasmania – Iron
August 12 2015: Avoca (Tasmania) – Iron 0.314mg/L
November 18 2015: Avoca (Tasmania) – Iron 0.347mg/L
March 9 2016: Avoca (Tasmania) – Iron 0.336mg/L
June 14 2016: Avoca (Tasmania) – Iron 0.966mg/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
Avoca (Tasmana) – pH (acidic)
Average pH: 2015 July-2016 June: 6.445 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, and can irritate skin if the water is used for ablutions.
Avoca – Tasmania – Temperature
November 24 2015: Avoca (Tasmania) – Temperature 20.5C
December 1 2015: Avoca (Tasmania) – Temperature 21.1C
December 8 2015: Avoca (Tasmania) – Temperature 20.9C
December 15 2015: Avoca (Tasmania) – Temperature 21.4C
December 22 2015: Avoca (Tasmania) – Temperature 24.7C
December 29 2015: Avoca (Tasmania) – Temperature 24C
January 5 2016: Avoca (Tasmania) – Temperature 20.8C
January 12 2016: Avoca (Tasmania) – Temperature 25.3C
January 19 2016: Avoca (Tasmania) – Temperature 24.3C
January 27 2016: Avoca (Tasmania) – Temperature 22.3C
February 2 2016: Avoca (Tasmania) – Temperature 24.4C
February 9 2016: Avoca (Tasmania) – Temperature 25.8C
February 16 2016: Avoca (Tasmania) – Temperature 21C
February 23 2016: Avoca (Tasmania) – Temperature 22.7C
March 1 2016: Avoca (Tasmania) – Temperature 21.5C
March 8 2016: Avoca (Tasmania) – Temperature 22.6C
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).
Avoca – Tasmania – Turbidity
2016/17: Avoca Turbidity 14.8 NTU (max), 1.57 NTU (mean)
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.