2/3/12 Echuca E. coli 4 org/100 mL Reticulation 3 org/100 mL Tank
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
Echuca (Victoria) – Anabaena circinalis
29/12/06: Echuca A.Circinalis 9500 cells/mL Increased monitoring and general surveillance. PAC considered but not used.
Due to the lack of adequate data, no guideline value is set for concentrations of saxitoxins.
However given the known toxicity, the relevant health authority should be notified
immediately if blooms of Anabaena circinalis (Dolichospermum circinalis)1 or other producers
of saxitoxins are detected in sources of drinking water.
There are three types of cyanobacterial neurotoxins: anatoxin a, anatoxin a-s and the saxitoxins. The saxitoxins include saxitoxin, neosaxitoxin, C-toxins and gonyautoxins (Chorus and Bartram 1999 Chapter 3). The anatoxins seem unique to cyanobacteria, while saxitoxins are also produced by various dinoflagellates under the name of paralytic shellfish poisons (PSPs). A number of cyanobacterial genera can produce neurotoxins, including Anabaena (Dolichospermum), Oscillatoria, Cylindrospermopsis, Cylindrospermum, Lyngbya and Aphanizomenon, but to date in Australia, neurotoxin production has only been detected from Anabaena circinalis (Dolichospermum circinalis), and the Australian isolates appear to
produce only saxitoxins (Velzeboer et al. 1998). As with most toxic cyanobacteria, A. circinalis (D. circinalis) tends to proliferate in calm, stable waters, particularly in summer when thermal stratification reduces mixing. The toxicity of individual populations of A. circinalis (D. circinalis) is variable, and one extensive survey of the toxicity across the Murray-Darling Basin indicated that 54% of field samples tested were neurotoxic (Baker and Humpage, 1994). A natural population may consist of a mixture of toxic and non-toxic strains and this is believed to explain why population toxicity may vary over time and between samples (Chorus and Bartram 1999 Chapter 3). The saxitoxins are a group of carbamoyl and decarbamoyl alkaloids that are either non-sulfated (saxitoxins), singly-sulfated (gonyautoxins), or doubly-sulfated (C-toxins). The various types of toxins vary in potency, with saxitoxin having the highest toxicity. The prevalent toxins in Australian blooms of A. circinalis are the C-toxins. These can convert in the environment or by acidification or boiling to more potent toxins (Negri et al. 1997, Ravn et al. 1995). The half-lives for breakdown of a range of different saxitoxins in natural water have been shown to vary from 9 to 28 days, and gonyautoxins may persist in the environment for more than three months (Jones and Negri, 1997).
Blooms of A. circinalis (D. circinalis) have been recorded in many rivers, lakes, reservoirs and dams throughout Australia, and A. circinalis (D. circinalis) is the most common organism in riverine blooms in the Murray-Darling Basin (Baker and Humpage 1994). In temperate parts of Australia blooms typically occur from late spring to early autumn. The first reported neurotoxic bloom of A. circinalis (D. circinalis) in Australia occurred in 1972 (May and McBarron 1973). The most publicised blooms occurred in the Murray-Darling System in 1991, 2009 and 2010 (NSWBGATF 1992, NSW Office of Water 2009, MDBA 2010). The first bloom extended over 1,000 kilometres of the Darling-Barwon River system in New South Wales (NSWBGATF 1992). A state of emergency was declared, with a focus on providing safe drinking water to towns, communities and landholders. Stock deaths were associated with the occurrence of the bloom but there was little evidence of human health impacts. The blooms in 2009 and 2010
affected several hundred kilometres of the River Murray on the border between NSW and Victoria and included Anabaena, Microcystis and Cylindrospermopsin. Alerts were issued about risks to recreational use, primary contact by domestic users, livestock and domestic animals. A bloom of A. circinalis (D. circinalis) in a dam in New South Wales was shown to have caused sheep deaths (Negri et al. 1995). Relatively low numbers of A. circinalis (D. circinalis) (below 2,000 cells/mL) can produce offensive tastes and odours in drinking water due to the production of odorous compounds such as geosmin… ADWG 2011
Echuca (Victoria) – Aluminium
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.
Echuca – Victoria – Total Dissolved Solids
2005/06: Echuca (Victoria) – Total Dissolved Solids 1100 μS/cm (max), 1000μS/cm (min)
“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
Taste – Echuca
21/3/12 Echuca Taste Flooding upstream of the raw water supply caused very high levels of taste and odour compounds in the raw water, exceeding the treatment capacity for some taste and odour compounds
Echuca (Victoria) Nickel
7/8/17: Echuca Nickel 0.05mg/L
A sample, collected from the distribution system, as part of Coliban Water’s sampling program, had an elevated level of nickel (0.05 mg/L), exceeding the health-based guideline value for
nickel (0.02mg/L) in the ADWG. The investigation concluded that the nickel exceedance was an
anomaly. No obvious cause of the exceedance was found, and the investigation showed this was an isolated incident and not an ongoing issue.
Nickel: ADWG Health Guideline 0.02mg/L. A chemical element and silvery white corrosion resistant metal with a golden tinge. 60% of nickel production is used in nickel steel (particularly stainless steel). In water, mainly a problem with nickel plated fittings. Main releases to the environment are from the burning of fossil fuels and in waste discharges from electroplating industries.