2005/23 – Laanecoorie (Victoria) – E.coli, Anabaena Circinalis, Lead, Trihalomethanes, NDMA, Hardness, Total Dissolved Solids, Sodium, Chloride, Turbidity, Manganese, Iron

Laanecoorie (Victoria) – Anabaena circinalis

9/3/07: Laanecoorie Anabaena circinalis count is at 5830 cells/mL
Increase general surveillance and PAC dosing commenced. Increased BGA testing until clear.

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.
GENERAL DESCRIPTION
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).

AUSTRALIAN SIGNIFICANCE
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

Laanecoorie (Victoria) – E.coli

18/4/07: Laanecoorie (Victoria) 2org/100mL. (sample at customer tap)

No known cause. All possible bird entry points checked. Chlorine residuals checked and seem OK. Re-sampling completed showing no further E.Coli.

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

Laanecoorie  (Victoria) Lead

2011/12 Laanecoorie Lead 0.08mg/L

Lead Australian Drinking Water Guideline 0.01mg/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…ADWG 2011

Laanecoorie (Victoria) – Trihalomethanes

19/2/16 Laanecoorie THM  0.3mg/L

4/3/20: Laanecoorie THM 0.25mg/L. The concentration of Total Trihalomethanes (THMs) exceeded the health-based guideline value (i.e. 0.25 mg/L) specified in the ADWG in samples
collected in the Laanecoorie water supply system between March and April 2020. The raw water for the Laanecoorie WTP is sourced from the Loddon River. Historically, raw water from the
Loddon River is high in Natural Organic Matter (NOM) and bromide. The water age in the
Laanecoorie system is also high due to the size of storage tanks and lengthy water mains. The
high-water age, along with the high levels of NOM and bromide, leads to the formation of excessive disinfection by products (DPBs). To manage this issue, primary disinfection at the Laanecoorie WTP is achieved through chlorination, and then the treated water is chloraminated. Nitrification is a common problem for chloraminated water supply
systems, which causes difficulties in maintaining adequate disinfectant residual. Therefore,
the disinfection process at the Laanecoorie WTP was changed from chloramination to chlorination to manage nitrification issue in the distribution network for a short
period of time (i.e. between 17 February 2020 to 14 April 2020).
The elevated THM results were due to a combination of the following: the temporary switch to
chlorination; high concentrations of NOM and bromide in the raw water; and the high-water age in the system. The non-compliant results that were recorded are as follows: 04/03/2020
Customer tap Laanecoorie 0.27 mg/L 12/03/2020. Bealiba Tank Outlet 0.26 mg/L; Tarnagulla Tank Outlet 0.31 mg/L; and  Customer tap Tarnagulla. 0.30 mg/L 29/04/2020 Bealiba Tank outlet 0.28 mg/L; and Customer tap Bealiba 0.31 mg/L

15/6/23 Laanecoorie, Bealiba, Dunolly & Tarnagulla. A routine sample collected from the Laanecoorie contact point had a THM’s result of 0.26 mg/L, which exceeded the ADWG health-based guideline value (0.25 mg/L).
The Laanecoorie WTP was optimised to manage the raw water quality it was receiving.
Additional sampling was arranged for the Tarnagulla, Bealiba and Dunolly, as the Laanecoorie WTP supplies all these towns. There were no non complaint results in these localities.

Trihalomethanes Australian Guideline Level 250μg/L (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”. US EPA

Laanecoorie (Victoria) – NDMA

1/6/20 Laanecoorie NDMA 290ng/L (customer tap)

1/6/20 Laanecoorie NDMA 160ng/L (WTP Storage Tank)

Since June 2020, the concentration of NNitrosodimethylamine (NDMA) has exceeded the health-based guideline value (i.e. 0.0001 mg/L) specified in the ADWG in samples collected from the Laanecoorie water supply system. NDMA is a disinfection by-product (DBP) of chloramination.
The non-compliant results that were recorded are as follows:
01/06/2020  Laanecoorie Water Treatment Plant Storage tank 0.00016 mg/L; Customer tap, Laanecoorie 0.00029 mg/L; and Customer tap Tarnagulla 0.00017 mg/L 24/06/2020 Customer tap Dunolly 0.00011mg/L

Given the health risks associated with DPBs, including NDMA, are based on life time exposure, occasional exceedances are considered low risk from a public health perspective. However, the
following corrective actions have been completed:
1. Checked and confirmed the chlorine: ammonia ratio that was being used to achieve chloramination was appropriate.
2. Increased the final water pH to ≥ 8.5. The samples tested for the presence of NDMA after the implementation of the corrective actions indicate that the actions were effective in reducing the
concentration of NDMA in the treated drinking water. Further investigations are currently
underway to better understand the root cause of the issue

“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