South Australia Water Corporation

Adelaide, Australia

South Australia Water Corporation

Adelaide, Australia
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Gaget V.,South Australia Water Corporation | Lau M.,South Australia Water Corporation | Sendall B.,39 Health | Froscio S.,South Australia Water Corporation | Humpage A.R.,South Australia Water Corporation
Water Research | Year: 2017

The presence of toxigenic cyanobacteria (blue-green algae) in drinking water reservoirs poses a risk to human and animal health worldwide. Guidelines and health alert levels have been issued in the Australian Drinking Water Guidelines for three major toxins, which are therefore the subject of routine monitoring: microcystin, cylindrospermopsin and saxitoxin. While it is agreed that these toxic compounds should be monitored closely, the routine surveillance of these bioactive chemicals can be done in various ways and deciding which technique to use can therefore be challenging. This study compared several assays available for the detection of these toxins and their producers in environmental samples: microscopy (for identification and enumeration of cyanobacteria), ELISA (Enzyme-Linked ImmunoSorbant Assay), PPIA (Protein phosphatase inhibition assay), PSI (Protein synthesis inhibition), chemical analysis and PCR (Polymerase Chain Reaction). Results showed that there was generally a good correlation between the presence of potentially toxigenic cyanobacteria and the detection of the toxin by ELISA. Nevertheless data suggest that cell numbers and toxin concentrations measured in bioassays do not necessarily correlate and that enumeration of potentially toxic cyanobacteria by microscopy, while commonly used for monitoring and risk assessment, is not the best indicator of real toxin exposure. The concentrations of saxitoxins quantified by ELISA were significantly different than those measured by LC-MS, while results were comparable in both assays for microcystin and cylindrospermopsin. The evaluation of these analytical methods led to the conclusion that there is no “gold standard” technique for the detection of the aforementioned cyanotoxins but that the choice of detection assay depends on cost, practicality, reliability and comparability of results and essentially on the question to be answered, notably on toxin exposure potential. © 2017 Elsevier Ltd

Gaget V.,University of AdelaideSouth Australia | Humpage A.R.,South Australia Water Corporation | Huang Q.,South Australia Water Corporation | Monis P.,University of AdelaideSouth Australia | And 2 more authors.
Water Research | Year: 2017

Cyanobacteria represent a health hazard worldwide due to their production of a range of highly potent toxins in diverse aquatic environments. While planktonic species have been the subject of many investigations in terms of risk assessment, little is known about benthic forms and their impact on water quality or human and animal health. This study aimed to purify isolates from environmental benthic biofilms sampled from three different drinking water reservoirs and to assess their toxin production by using the following methods: Enzyme-Linked Immunosorbent Assay (ELISA), High-Performance Liquid Chromatography (HPLC), Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS) and quantitative PCR (qPCR). Microscopic observation of the isolates allowed the identification of various filamentous cyanobacterial genera: Anabaena (benthic form), Calothrix and Nostoc from the Nostocales and Geitlerinema, Leptolyngbya, Limnothrix, Lyngbya, Oxynema, Phormidium and Pseudanabaena representing non-heterocystous filamentous cyanobacteria. The Phormidium ambiguum strain AWQC-PHO021 was found to produce 739 ng/mg of dry weight (d/w) of cylindrospermopsin and 107 ng/mg (d/w) of deoxy-cylindrospermopsin. The Nostoc linckia strain AWQC-NOS001 produced 400 ng/mg (d/w) of a microcystin analogue. This is the first report of hepatotoxin production by benthic cyanobacteria in temperate Australian drinking water reservoirs. These findings indicate that water quality monitoring programs need to consider benthic cyanobacteria as a potential source of toxins. © 2017

Su M.,CAS Research Center for Eco Environmental Sciences | Gaget V.,South Australia Water Corporation | Gaget V.,University of Adelaide | Giglio S.,South Australia Water Corporation | And 3 more authors.
Water Research | Year: 2013

Geosmin has often been associated with off-flavor problems in drinking water with Anabaena sp. as the major producer. Rapid on-site detection of geosmin-producers as well as geosmin is important for a timely management response to potential off-flavor events. In this study, quantitative polymerase chain reaction (qPCR) methods were developed to detect the levels of Anabaena sp. and geosmin, respectively, by designing two PCR primer sets to quantify the rpoC1 gene (ARG) and geosmin synthase one (GSG) in Anabaena sp. in freshwater systems. The ARG density determined by qPCR assay is highly related to microscopic cell count (r2=0.726, p<0.001), and the limit of detection (LOD) and limit of quantification (LOQ) of the qPCR method were 0.02pg and 0.2pg of DNA, respectively. At the same time, the relationship between geosmin concentrations measured by gas chromatography-mass spectrometry (GC-MS) and GSG copies was also established (r2=0.742, p<0.001) with similar LOD and LOQ values. Using the two qPCR protocols, we succeeded in measuring different levels of ARG and GSG copies in different freshwater systems with high incidence environmental substrata and diverse ecological conditions, showing that the methods developed could be applied for environmental monitoring. Moreover, comparing to the microscopic count and GC-MS analytical methods, the qPCR methods can reduce the time-to-results from several days to a few hours and require considerably less traditional algal identification and taxonomic expertise. © 2013 Elsevier Ltd.

Shaw J.L.A.,University of Adelaide | Shaw J.L.A.,CSIRO | Monis P.,South Australia Water Corporation | Weyrich L.S.,University of Adelaide | And 3 more authors.
Applied and Environmental Microbiology | Year: 2015

Drinking water assessments use a variety of microbial, physical, and chemical indicators to evaluate water treatment efficiency and product water quality. However, these indicators do not allow the complex biological communities, which can adversely impact the performance of drinking water distribution systems (DWDSs), to be characterized. Entire bacterial communities can be studied quickly and inexpensively using targeted metagenomic amplicon sequencing. Here, amplicon sequencing of the 16S rRNA gene region was performed alongside traditional water quality measures to assess the health, quality, and efficiency of two distinct, full-scale DWDSs: (i) a linear DWDS supplied with unfiltered water subjected to basic disinfection before distribution and (ii) a complex, branching DWDS treated by a four-stage water treatment plant (WTP) prior to disinfection and distribution. In both DWDSs bacterial communities differed significantly after disinfection, demonstrating the effectiveness of both treatment regimes. However, bacterial repopulation occurred further along in the DWDSs, and some end-user samples were more similar to the source water than to the postdisinfection water. Three sample locations appeared to be nitrified, displaying elevated nitrate levels and decreased ammonia levels, and nitrifying bacterial species, such as Nitrospira, were detected. Burkholderiales were abundant in samples containing large amounts of monochloramine, indicating resistance to disinfection. Genera known to contain pathogenic and fecal-associated species were also identified in several locations. From this study, we conclude that metagenomic amplicon sequencing is an informative method to support current compliance-based methods and can be used to reveal bacterial community interactions with the chemical and physical properties of DWDSs. © 2015, American Society for Microbiology.

PubMed | University of Adelaide and South Australia Water Corporation
Type: | Journal: Journal of applied microbiology | Year: 2016

Benthic Cyanobacteria produce toxic and odorous compounds similar to their planktonic counterparts, challenging the quality of drinking water supplies. The biofilm that benthic algae and other micro-organisms produce is a complex and protective matrix. Monitoring to determine the abundance and identification of Cyanobacteria, therefore, relies on molecular techniques, with the choice of DNA isolation technique critical. This study investigated which DNA extraction method is optimal for DNA recovery in order to guarantee the best DNA yield for PCR-based analysis of benthic Cyanobacteria.The conventional phenol-chloroform extraction method was compared with five commercial kits, with the addition of chemical and physical cell-lysis steps also trialled. The efficacy of the various methods was evaluated by measuring the quantity and quality of DNA by UV spectrophotometry and by quantitative PCR (qPCR) using Cyanobacteria-specific primers. The yield and quality of DNA retrieved with the commercial kits was significantly higher than that of DNA obtained with the phenol-chloroform protocol.Kits including a physical cell-lysis step, such as the MO BIO Power Soil and Biofilm kits, were the most efficient for DNA isolation from benthic Cyanobacteria.These commercial kits allow greater recovery and the elimination of dangerous chemicals for DNA extraction, making them the method of choice for the isolation of DNA from benthic mats. They also facilitate the extraction of DNA from benthic Cyanobacteria, which can help to improve the characterization of Cyanobacteria in environmental studies using qPCRs or population composition analysis using next-generation sequencing.

PubMed | Australian Water Quality Center and South Australia Water Corporation
Type: | Journal: Water research | Year: 2014

Protozoan pathogens present a significant human health concern, and prevention of contamination into potable networks remains a key focus for drinking water providers. Here, we monitored the change in Cryptosporidium concentration in source water during high flow events in a multi-use catchment. Furthermore, we investigated the diversity of Cryptosporidium species/genotypes present in the source water, and delivered an oocyst infectivity fraction. There was a positive and significant correlation between Cryptosporidium concentration and flow ( = 0.756) and turbidity ( = 0.631) for all rainfall-runoff events, despite variable source water pathogen concentrations. Cell culture assays measured oocyst infectivity and suggested an overall source water infectious fraction of 3.1%. No infectious Cryptosporidium parvum or Cryptosporidium hominis were detected, although molecular testing detected C. parvum in 7% of the samples analysed using PCR-based molecular techniques. Twelve Cryptosporidium species/genotypes were identified using molecular techniques, and were reflective of the host animals typically found in remnant vegetation and agricultural areas. The inclusion of molecular approaches to identify Cryptosporidium species and genotypes highlighted the diversity of pathogens in water, which originated from various sources across the catchment. We suggest this mixing of runoff water from a range of landuses containing diverse Cryptosporidium hosts is a key explanation for the often-cited difficulty forming strong pathogen-indicator relationships.

Swaffer B.A.,South Australia Water Corporation | Swaffer B.A.,Flinders University | Holland K.L.,CSIRO | Doody T.M.,CSIRO | And 2 more authors.
Hydrological Processes | Year: 2014

The flow of precipitation from the surface through to groundwater in karst systems is a complex process involving storage in the unsaturated zone and diffuse and preferential recharge pathways. The processes associated with this behaviour are not well understood, despite the prevalence of karst aquifers being used as freshwater supplies. As a result, uncertainty regarding the ecohydrological processes in this geological setting remains large. In response to the need to better understand the impact of woody vegetation on groundwater recharge, annual evapotranspiration (ET) rates and tree water sources were measured for two years above a shallow, fresh karst aquifer. Water use strategies of the co-occurring Eucalyptus diversifolia subsp. diversifolia Bonpl. and Allocasuarina verticillata (Lam.) L. Johnson were investigated using a monthly water balance approach, in conjunction with measurement of the stable isotopes of water, leaf water potentials and soil matric potentials. The results suggest that it is unlikely groundwater resources are required to sustain tree transpiration, despite its shallow proximity to the soil surface, and that similarities exist between ET losses and the estimated long-term average rainfall for this area. Irrespective of stand and morphological differences, E. diversifolia and A. verticillata ET rates showed remarkable convergence, demonstrating the ability of these co-occurring species to maximise their use of the available precipitation, which avoids the requirement to differentiate between these species when estimating ET at a landscape scale. We conclude that the water holding capacity of porous geological substrates, such as those associated with karst systems, will play an important role in equilibrating annual rainfall variability and should be considered when assessing ecohydrological links associated with karst systems. © 2013 John Wiley & Sons, Ltd.

Swaffer B.A.,South Australia Water Corporation | Swaffer B.A.,Flinders University | Holland K.L.,CSIRO
Ecohydrology | Year: 2015

Invasion by exotic plant species into water-limited environments has the potential to change the ecosystem water balance and may further exacerbate water scarcity issues. Here, we compared ecophysiological traits related to tree water use (sap flux, sapwood density, leaf and soil water potentials) and actual evapotranspiration (ETa) of the invasive Pinus halepensis to native tree and shrub species. We hypothesized that the invasive pine species would possess traits that are consistent with the potential to use more water than native species, which would be supported by higher ETa in areas invaded by pine. We found higher rates of sap flux for the invasive P.halepensis (5.5cmh-1) per unit sapwood area compared with the native species (<3.5cmh-1). In addition, P.halepensis sapwood was significantly less dense than the sapwood of the native species, suggesting higher sapwood conductivity facilitated the faster sap flux. Comparison of remotely sensed ETa before and after P.halepensis removal within a Eucalyptus camaldulensis stand demonstrated a reduction in ETa by an average of 50(±11 SE)mmyear-1 in the 2years after removal, relative to the ETa from an undisturbed, intact E. camaldulensis stand. This study suggests that active management of this invasive species should reduce overall ETa losses and thereby exert a positive influence on the availability of soil moisture for groundwater recharge. © 2014 John Wiley & Sons, Ltd.

Morran J.,South Australia Water Corporation | Drikas M.,South Australia Water Corporation
Journal - American Water Works Association | Year: 2011

The formation of nitrosamines in drinking water was first reported in the early 1990s. These compounds are classified as probable human carcinogens, so their control presents a challenge to authorities in providing a safe water supply to the public. Generally, nitrosamines in water supplies are the result of disinfection by chlorine or chloramines, and the standard control strategy has been to minimize their formation by changing treatment processes, often including the addition of an ultraviolet irradiation stage. This problem has now been exacerbated by the discovery that high levels of N-nitrosodimethylamine (NDMA) in newly constructed pipelines result from NDMA leaching from the rubber sealing rings used to connect the pipes. This study strongly suggests that NDMA and other nitrosamines could be present for several years in distribution systems with rubber components. Furthermore, the occurrence of nitrosamines in drinking water was independent of both the type and presence of disinfectant.2011 © American Water Works Association.

Dixon M.B.,South Australia Water Corporation | Lasslett S.,South Australia Water Corporation | Pelekani C.,South Australia Water Corporation
Desalination | Year: 2012

In preparation for the operation of the 300. ML/day Adelaide Desalination Plant, a pilot plant was constructed to evaluate anticipated operational challenges, such as biofouling. Various methods for the control of biofouling have been proposed, however, in-situ early tools for detection of biofouling conditions in spiral wound reverse osmosis elements remain elusive. The current study investigated the use of novel methods for assessment of biofouling potential, using process stream samples obtained from the Adelaide Desalination Pilot Plant (ADPP). Non-destructive methods, including flow cytometry (FCM) and bacterial regrowth potential (BRP) analysis were used. X-ray photoelectron spectroscopy (XPS) and Time of Flight-Secondary Ion Mass Spectroscopy (ToF-SIMS) analyses were employed during destructive membrane autopsy to compliment the findings of the FCM & BRP. 16S rRNA analysis was undertaken on seawater samples and autopsied membrane elements to evaluate whether sampling of bulk process streams could provide early warning of potential RO membrane biofouling bacteria. BRP analysis allowed for calculation of whether had assimilable organic carbon (AOC) was consumed by biofilm on the membrane or being sloughing from the surface. XPS and ToF-SMIS analysis facilitated detection of polysaccharides and proteins adhered to the membrane surface. ToF-SIMS also allowed for the detection of foreign chemical contaminant (i.e. organosilicone). 16S rRNA analysis identified the bacteria species within the biofilm. It also allowed for non-destructive analysis of the biofilm microbial composition via swabbing of the RO element's exterior case. 16S rRNA analysis of biofilm on the exterior surface of an RO element correlated well with the microbial composition of internal membrane surface biofilm. This finding could assist utilities as a rapid, non-destructive assessment of potentially biofouling species. © 2012 Elsevier B.V.

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