Maryborough (Victoria) – NDMA
2015/16 Maryborough NDMA 0.091ug/L
7 July 2016 Maryborough Clear Water Storage Outlet (Entry point to Marybrough system) NDMA – 0.22 μg/L Maryborough reticulation
Informed DHHS. Reviewed past history of NDMA trends. Conducted further extensive sampling of treated water concentrations and tested for precursor compounds in the raw water supply. Commenced a comprehensive investigation into potential formation pathways which included sampling throughout the treatment train and investigations into current water treatment chemicals and disinfection conditions. External experts
consulted to assist in complex investigations. NDMA formation potential tests completed on chemical dosing systems to ensure no contributions from plant components. Non-critical chemical dosing systems deactivated to determine NDMA response. System reactivated with compliant NDMA results. Routine NDMA test frequency increased on an ongoing basis to more closely monitor for any fluctuations.
1/9/16 Maryborough NDMA 180ng/L
1/9/16 Maryborough NDMA 210ng/L (Gladstone Street)
“Based on health considerations, the concentration of NDMA in drinking water should not
exceed 0.0001 mg/L (100 ng/L). Action to reduce NDMA is encouraged, but must not compromise disinfection, as non disinfected water poses significantly greater risk than NDMA.
NDMA is used as an industrial solvent, an anti-oxidant, a rubber accelerator, and in the preparation of polymers, where it may be used as an initiator or a plasticiser. The compound has been used in the production of rocket fuel, as a biocide for nematodes, and an intermediate for 1,1-dimethylhydrazine to inhibit nitrification of soils.
NDMA is formed under mildly acidic conditions by the reaction of natural and synthetic secondary, tertiary or quaternary amines with nitrate and nitrite. Precursor amines include alkylamines, dimethylamine (DMA), tetramethylthiuram disulfide (thiram) and polyelectrolytes used in water and wastewater treatment. NDMA is also produced as a by-product of chloramination of drinking water (due to the presence of dimethylamine in source waters subject to wastewater discharges or the oxidation of natural organic matter by chlorine in the presence of ammonia) and to a lesser extent by chlorination. NDMA formation can be facilitated in soils by biochemical pathways in micro-organisms, and this compound is resistant to microbial degradation under both aerobic and anaerobic conditions. Ozonation of drinking water contaminated with the fungicide tolyfluamide can also lead to the formation of NDMA…
TYPICAL VALUES IN AUSTRALIAN DRINKING WATER
There are no data in the public domain or peer reviewed literature on NDMA in Australian drinking water distribution systems and water treatment plants. Anecdotal evidence suggests a bi-modal distribution, with several water authorities indicating that NDMA is present at levels at or near the limit of determination of 1 to 2 ng/L, whereas preliminary sampling and analysis by other authorities indicates levels in the range of 60-90 ng/L. A recent report from South Australia has indicated that NDMA may originate from rubber components of newly commissioned drinking water pipelines, regardless of the disinfectant used. This
may account at least partly for the divergent results reported by different water suppliers…” ADWG 2011
Maryborough (Victoria) – Trihalomethanes
7 & 8 July 2008: Maryborough Customer Tap – Trihalomethanes 0.360mg/L. Commissioning of chloramination plant in November 2008 for water quality improvements. Informed DHS. One
Section 22 submitted for all THM non-compliances expected to occur until 30 August 2009.
7 October 2008: Maryborough Cutomer Tap Trihalomethanes 0.370mg/L. Commissioning of chloramination plant in November 2008. Informed DHS. One Section 22 submitted for all THM
non-compliances expected to occur until 30 November 2008.
11 November 2008: Maryborough Cutomer Tap Trihalomethanes 0.348mg/L. Commissioning of chloramination plant in November 2008. Informed DHS. One Section 22 submitted for all THM
non-compliances expected to occur until 31 December 2008.
2008/9 Maryborough Trihalomethanes 0.480mg/L (Highest Level)
2007/8 Maryborough Trihalomethanes 0.510mg/L (Highest Level)
Trihalomethanes Australian Guideline Level 0.25mg/L
Why and how are THMs formed?
“When chlorine is added to water with organic material, such as algae, river weeds, and decaying leaves, THMs are formed. Residual chlorine molecules react with this harmless organic material to form a group of chlorinated chemical compounds, THMs. They are tasteless and odourless, but harmful and potentially toxic. The quantity of by-products formed is determined by several factors, such as the amount and type of organic material present in water, temperature, pH, chlorine dosage, contact time available for chlorine, and bromide concentration in the water. The organic matter in water mainly consists of a) humic substance, which is the organic portion of soil that remains after prolonged microbial decomposition formed by the decay of leaves, wood, and other vegetable matter; and b) fulvic acid, which is a water soluble substance of low molecular weight that is derived from humus”. Source: https://water.epa.gov/drink/contaminants/index.cfm
Maryborough (Victoria) – Mercury
Highest Victorian Reading 2005-11: Maryborough 0.002mg/L Central Highlands Water 2009/10
Mercury: ADWG Guideline 0.001mg/L
Mercury, if it enters the ecosystem can transform into the more toxic methylmercury where it can bioaccumulate. Methylmercury is highly toxic to human embryos, fetuses, infants and children. Mercury has numerous sources including old gold mines, where mercury was used in gold recovery process. It has been estimated that 950 tonnes of mercury was deposited into Victorian soil, rivers and streams during the various gold rushes.
https://ntn.org.au/wp-content/uploads/2010/05/mercury_brief20101.pdf
Maryborough – Victoria – Turbidity
2008/09: Maryborough (Victoria) – Turbidity 6 NTU
2016/17: Maryborough Turbidity 13NTU
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.
Maryborough – Victoria – Total Dissolved Solids
2008/9: Maryborough (Victoria) – Total Dissolved Solids 1600 mg/L
2009/10: Maryborough (Victoria) – Total Dissolved Solids 850 mg/L
2010/11: Maryborough (Victoria) – Total Dissolved Solids 900 mg/L
2015/16: Maryborough Total Dissolved Solids 700mg/L
2016/17: Maryborough Total Dissolved Solids 700mg/L
GUIDELINE
“No specific health guideline value is provided for total dissolved solids (TDS), as there are no
health effects directly attributable to TDS. However for good palatability total dissolved solids
in drinking water should not exceed 600 mg/L.
Total dissolved solids (TDS) consist of inorganic salts and small amounts of organic matter that are dissolved in water. Clay particles, colloidal iron and manganese oxides and silica, fine enough to pass through a 0.45 micron filter membrane can also contribute to total dissolved solids.
Total dissolved solids comprise: sodium, potassium, calcium, magnesium, chloride, sulfate, bicarbonate, carbonate, silica, organic matter, fluoride, iron, manganese, nitrate, nitrite and phosphates…” Australian Drinking Water Guidelines 2011
Maryborough – Victoria – Hardness
2008/09: Maryborough (Victoria) – Hardness 780mg/L
2009/10: Maryborough (Victoria) – Hardness 380mg/L
2010/11: Maryborough (Victoria) – Hardness 440mg/L
2013/14: Maryborough Hardness 220mg/L
2014/15: Maryborough Hardness 280mg/L
2015/16 Maryborough Hardness 390mg/L
2016/17: Maryborough Hardness 380mg/L
2018/19: Maryborough Hardness 220mg/L
GUIDELINE
“To minimise undesirable build‑up of scale in hot water systems, total hardness (as calcium
carbonate) in drinking water should not exceed 200 mg/L.
Hard water requires more soap than soft water to obtain a lather. It can also cause scale to form on hot water pipes and fittings. Hardness is caused primarily by the presence of calcium and magnesium ions, although other cations such as strontium, iron, manganese and barium can also contribute.”
Australian Drinking Water Guidelines 2011
Maryborough – Victoria – Iron
2008/09: Maryborough (Victoria) – Iron 0.39mg/L (Highest level only)
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
Maryborough (Victoria) – pH (alkaline)
Average pH: 2017-18: 8.6 pH units
Average pH: 2018-19: 8.6 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.
Maryborough (Victoria) – Taste & Odour
18 November 2011 (13 days) Maryborough (All Localities) Widespread customer taste and odour complaints (45) Maryborough Reticulation (All Localities)
Maryborough (Victoria)
2019/20: Maryborough Gross Alpha Activity 0.46 (Bq/L)
2019/20: Maryborough Gross Beta Activity 0.45 (Bq/L)
Radionuclides (Other beta- and gamma-emitting)
GUIDELINE
No specific guideline values are set for beta- or gamma-emitting radionuclides.
Specific beta- or gamma-emitting radionuclides should be identified and determined only
if gross beta radioactivity (after subtracting the contribution of potassium-40) exceeds 0.5 Bq/L (27.6 Bq of beta activity per gram of stable potassium).
GENERAL DESCRIPTION
Several radionuclides that are classified as beta-particle or gamma-ray emitters may occasionally be present in drinking water. The significant long-lived nuclides in this group are the naturally occurring isotopes potassium-40, lead-210 and radium-228, and artificial radionuclides caesium-137 and strontium-90. Tritium, another nuclide in this group, is present in the environment both from natural sources and as a result of nuclear fall-out and nuclear power generation.
Levels of strontium-90 and caesium-137 in the Australian environment have decreased substantially since atmospheric testing of nuclear weapons ceased, and these radionuclides are not detectable in drinking water. In the absence of a nuclear power industry in Australia, these nuclides are likely to be present in significant concentrations in drinking water only as a result of transient contamination following an event such as a nuclear accident.
Potassium‑40 occurs naturally in a fixed ratio to stable potassium. Potassium is an essential element for humans, and is absorbed mainly from ingested food. Potassium-40 does not accumulate in the body but is maintained at a constant level independent of intake. The average concentration of potassium in an adult male is about 2 g/kg of bodyweight, which gives an activity mass concentration of potassium-40 of 60 Bq per kg of bodyweight. The corresponding value for females is slightly less.
Lead-210, like radium-226, is a decay product of the uranium-238 series. Food is the most important route by which lead-210 enters the human body, and the annual intake depends on diet: highest concentrations are found in fish and other aquatic species. Generally, lead-210 concentrations in drinking water are considerably less than concentrations of either radium-226 or radium-228.
TYPICAL VALUES IN AUSTRALIAN DRINKING WATER
Concentrations of potassium-40 in Australian drinking water supplies vary widely, from below 0.05 Bq/L in surface water sources to more that 1 Bq/L in some supplies drawn from groundwater.
There are only limited data on concentrations of other beta- or gamma-emitting radionuclides such as lead-210, strontium-90 and caesium-137 in Australian drinking water supplies. Lead-210 concentrations are probably below 0.05 Bq/L and concentrations of artificial radionuclides are negligible.