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Humpage A.,Australian Water Quality Center | Falconer I.,University of Adelaide | Bernard C.,Australian Water Quality Center | Bernard C.,Central Queensland University | And 2 more authors.
Water Research | Year: 2012

A growing list of freshwater cyanobacteria are known to produce toxic agents, a fact which makes these organisms of concern to water authorities. A cultured strain of Limnothrix (AC0243) was recently shown to have toxic effects in invitro bioassays. It did not produce any of the known cyanobacterial toxins. The intrapertoneal toxicity of aqueous extracts of the material was therefore tested in mice to determine whether the observed effects might be of public health relevance to drinking water supplies. The results indicate that Limnothrix AC0243 is acutely toxic to mice, causing widespread cellular necrosis in the liver, kidneys and gastrointestinal tract within 24h of exposure. Sub-lethal effects lasted at least 7d. These results suggest that Limnothrix AC0243 produces a novel toxin ("Limnothrixin") and that further work is therefore urgently required to quantify the potential public health implications. © 2011 Elsevier Ltd.

Connolly R.M.,Griffith University | Gorman D.,South Australian Research And Development Institute | Hindell J.S.,Heidelberg VIC | Kildea T.N.,Australian Water Quality Center | Schlacher T.A.,University of The Sunshine Coast
Marine Pollution Bulletin | Year: 2013

Assessments of sewage pollution routinely employ stable nitrogen isotope analysis (δ15N) in biota, but multiple taxa are rarely used. This single species focus leads to underreporting of whether derived spatial N patterns are consistent. Here we test the question of 'reproducibility', incorporating 'taxonomic replication' in the measurement of δ15N gradients in algae, seagrasses, crabs and fish with distance from a sewage outfall on the Adelaide coast (southern Australia). Isotopic sewage signals were equally strong in all taxa and declined at the same rate. This congruence amongst taxa has not been reported previously. It implies that sewage-N propagates to fish via a tight spatial coupling between production and consumption processes, resulting from limited animal movement that closely preserves the spatial pollution imprint. In situations such as this where consumers mirror pollution signals of primary producers, analyses of higher trophic levels will capture a broader ambit of ecological effects. © 2013 Elsevier Ltd.

Al-Tebrineh J.,University of New South Wales | Merrick C.,Sydney Water | Ryan D.,Sydney Water | Humpage A.,Australian Water Quality Center | And 3 more authors.
Applied and Environmental Microbiology | Year: 2012

A cyanobacterial bloom impacted over 1,100 km of the Murray River, Australia, and its tributaries in 2009. Physicochemical conditions in the river were optimal to support a bloom at the time. The data suggest that at least three blooms occurred concurrently in different sections of the river, with each having a different community composition and associated cyanotoxin profile. Microscopic and genetic analyses suggested the presence of potentially toxic Anabaena circinalis, Microcystis flos-aquae, and Cylindrospermopsis raciborskii at many locations. Low concentrations of saxitoxins and cylindrospermopsin were detected in Anabaena and Cylindrospermopsis populations. A multiplex quantitative PCR was used, employing novel oligonucleotide primers and fluorescent TaqMan probes, to examine bloom toxigenicity. This single reaction method identified the presence of the major cyanotoxin-producing species present in these environmental samples and also quantified the various toxin biosynthesis genes. A large number of cells present throughout the bloom were not potential toxin producers or were present in numbers below the limit of detection of the assay and therefore not an immediate health risk. Potential toxin-producing cells, possessing the cylindrospermopsin biosynthesis gene (cyrA), predominated early in the bloom, while those possessing the saxitoxin biosynthesis gene (sxtA) were more common toward its decline. In this study, the concentrations of cyanotoxins measured via enzymelinked immunosorbent assay (ELISA) correlated positively with the respective toxin gene copy numbers, indicating that the molecular method may be used as a proxy for bloom risk assessment. © 2012, American Society for Microbiology.

Chessman B.C.,New South Wales Office of Environment and Heritage | McEvoy P.K.,Australian Water Quality Center
Water, Air, and Soil Pollution | Year: 2012

We present the concept of assemblage tolerance profiles (ATPs) as an aid to freshwater bioassessment, and illustrate it with a practical example. An ATP describes the proportion of taxa in an observed assemblage that is estimated to tolerate each level of a specific stressor within a defined range. We used an extensive compilation of biomonitoring field data to estimate the lower tolerances for pH and dissolved oxygen (DO) of common families of macroinvertebrates in rivers of south-eastern Australia. These limits were then used to establish ATPs for macroinvertebrate assemblages at 30 sites across six river systems with varying levels of exposure to drainage from disused mines and discharges from sewage treatment plants.We hypothesised that sites with more exposure to mine drainage would have ATPs indicating greater tolerance of low pH, whereas sites with more exposure to sewage discharges would have ATPs indicating greater tolerance of low DO, and found that these hypotheses were confirmed for five of the six river systems. We suggest that stressor-specific ATPs, based on tolerances derived from either field distributions or laboratory tests, can help to verify or eliminate candidate causes of inferred human impacts on aquatic ecosystems. © Springer Science+Business Media B.V. 2011.

Humpage A.R.,Australian Water Quality Center | Froscio S.M.,Australian Water Quality Center | Lau H.-M.,Australian Water Quality Center | Murphy D.,Melbourne Water Corporation | Blackbeard J.,Melbourne Water Corporation
Water Research | Year: 2012

Rapid tests for the microcystin-type cyanobacterial toxins that are designed to be able to be used in the field have recently become available. The tests provide a semi-quantitative result over a relatively narrow concentration range (10-fold) and are available with detection limits relevant for drinking water and recreational water compliance testing (1. μg/L and 10. μg/L, respectively). The aim of this research was to assess the applicability of these tests for the determination of microcystin-related toxicity in treated effluent from the Western Treatment Plant and potable source water from Tarago Reservoir, both near Melbourne, Australia. Accuracy, precision, cross-reactivity, matrix effects and inter-operator variability were assessed. The claimed mLR concentration response range of the tests was confirmed within reasonable limits, although the false negative and false positive rates were significant for spike concentrations below 2.5. μg/L (Recreational Strip Test). Inter-operator variability was reasonably high (CV = 23%) and this was exacerbated by the use of untrained scorers. Contributing to this was significant inter-assay variability in test band intensity (CV = 28%). The strip tests responded to all 8 microcystin analogues tested and also to a mixture of another 7 analogues contained in a Certified Bloom Material. Cross-reactivity was always greater than 50%. Matrix effects due to the test waters or to cyanobacterial cell material were also relatively minor, being of the order of 2-fold at the maximum. Overall, these Strip Tests were found to be reliable for relatively rapid detection of microcystins around the upper limits of their response ranges, as recommended by the manufacturer. While the Recreational Water Strip test was less reliable in the lower ranges, it can be used in conjunction with the Drinking Water Strip test to reduce uncertainty around the 1. μg/L concentration. Despite limitations, both strip tests provide near real-time information which can assist with day to day operational decisions. When results indicate microcystin concentrations near compliance limits it is recommended that use of the test kits should be supported by accurate quantitative toxin testing together with traditional algal cell counts, and possibly emerging qPCR methods for species and toxin gene detection. © 2011 Elsevier Ltd.

Leusch F.D.L.,Griffith University | Khan S.J.,University of New South Wales | Laingam S.,Australian Water Quality Center | Prochazka E.,Griffith University | And 4 more authors.
Water Research | Year: 2014

The growing use of recycled water in large urban centres requires comprehensive public health risk assessment and management, an important aspect of which is the assessment and management of residual trace chemical substances. Bioanalytical methods such as invitro bioassays may be ideal screening tools that can detect a wide range of contaminants based on their biological effect. In this study, we applied thirteen invitro assays selected explicitly for their ability to detect molecular and cellular effects relevant to potential chemical exposure via drinking water as a means of screening for chemical contaminants from recycled water at 9 Australian water reclamation plants, in parallel to more targeted direct chemical analysis of 39 priority compounds. The selected assays provided measures of primary non-specific (cytotoxicity to various cell types), specific (inhibition of acetylcholinesterase and endocrine receptor-mediated effects) and reactive toxicity (mutagenicity and genotoxicity), as well as markers of adaptive stress response (modulation of cytokine production) and xenobiotic metabolism (liver enzyme induction). Chemical and bioassay analyses were in agreement and complementary to each other: the results show that source water (treated wastewater) contained high levels of biologically active compounds, with positive results in almost all bioassays. The quality of the product water (reclaimed water) was only marginally better after ultrafiltration or dissolved air floatation/filtration, but greatly improved after reverse osmosis often reducing biological activity to below detection limit. The bioassays were able to detect activity at concentrations below current chemical method detection limits and provided a sum measure of all biologically active compounds for that bioassay, thus providing an additional degree of confidence in water quality. © 2013 Elsevier Ltd.

Roccaro P.,University of Catania | Korshin G.V.,University of Washington | Cook D.,Australian Water Quality Center | Chow C.W.K.,Australian Water Quality Center | Drikas M.,Australian Water Quality Center
Water Research | Year: 2014

This study investigated effects of pH, bromide and natural organic matter (NOM) level on yields and speciation of trihalomethanes (THMs) and haloacetic acids (HAAs) in chlorinated water. Experimental data were obtained using two water sources, one with a medium (DOC=1.4mg/L and SUVA=2.60Lmg-1m-1) and the other with higher (DOC=7.7mg/L and SUVA=4.26Lmg-1m-1) organic carbon level. The experiments employed the simulated distribution system (SDS) procedure at varying bromide concentrations and pH values of 7.0, 8.5 and 10. The speciation of THMs and dihalogenated HAAs (DHAAs) was interpreted based on the modelling of mixed halogenation yields via dimensionless ratios of bromination/chlorination reaction rates at each halogen incorporation node. The approach allowed precise modelling of the speciation of THMs and DHAAs at all examined pHs. In the case of DHAA, the dimensionless ratios of the bromination/chlorination reaction rates were not consistently affected by pH variations. For THMs, increase of pH caused the values of the dimensionless bromination/chlorination reaction rates to decrease in the case of halogenation of the initial reaction sites indicating a decreasing preference toward bromination at this reaction node. A similar trend was observed for the reactivity of dichlorinated reaction intermediate denoted as SCl2 whose formation precedes the release of CHCl3 and CHBrCl2. A similar but less consistent trend was observed for intermediate SBrCl whose halogenation yields both CHBrCl2 and CHBr2Cl. An opposite trend of increasing preference towards bromination at higher pHs was observed monobrominated intermediate SBr and in some extent dibrominated intermediate SBr2. These results help develop detailed DBP speciation models which needed to better understand the generation and potential health effects of THMs and HAAs at varying operating conditions and ultimately to adopt measure to minimize their levels in drinking water systems. © 2014 Elsevier Ltd.

Laingam S.,Australian Water Quality Center | Froscio S.M.,Australian Water Quality Center | Bull R.J.,MoBull Consulting | Humpage A.R.,Australian Water Quality Center
Environmental and Molecular Mutagenesis | Year: 2012

Disinfection by-products (DBPs) are of concern to both water industries and health authorities. Although several classes of DBPs have been studied, and there are regulated safe levels in disinfected water for some, a large portion of DBPs are not characterized, and need further investigation. Organic N-chloramines are a group of DBPs, which can be formed during common disinfection processes such as chlorination and chloramination, but little is known in terms of their toxicological significance if consumed in drinking water. Only a few in vitro studies using bacterial assays have reported some genotoxic potential of organic N-chloramines, largely in the context of inflammatory processes in the body rather than exposure through drinking water. In this study, we investigated 16 organic N-chloramines produced by chlorination of model amino acids and amines. It was found that within the drinking water-relevant micromolar concentration range, four compounds were both cytotoxic and genotoxic to mammalian cells. A small reduction of cellular GSH was also observed in the treatment with these four compounds, but not of a magnitude to account for the cytotoxicity and genotoxicity. The results presented in this study demonstrate that some organic N-chloramines, at low concentrations that might be present in disinfected water, can be harmful to mammalian cells. © 2011 Wiley Periodicals, Inc.

Li Z.,CAS Research Center for Eco Environmental Sciences | Yu J.,CAS Research Center for Eco Environmental Sciences | Yang M.,CAS Research Center for Eco Environmental Sciences | Zhang J.,CAS Research Center for Eco Environmental Sciences | And 3 more authors.
Harmful Algae | Year: 2010

A significant outbreak of odorous and toxic cyanobacteria occurred in Yanghe Reservoir, North China, in the summer of 2007. The dominant species was Anabaena spiroides and it was accompanied with the occurrence of very high concentrations of the odor metabolite geosmin. The event included two cycles of growth of A. spiroides: the first one of approximately 16 days between 21 June and 8 July, with the peak density 70,000cellsmL-1 on 2 July, and the second smaller bloom of over 50 days between 9 July and the end of August. The bloom also included a range of species of Microcystis, predominantly M. aeruginosa, as the second largest population, which varied from 5800cellsmL-1 to 28,000cellsmL-1 in the first cycle and from 2000cellsmL-1 to 11,000cellsmL-1 in the second. Geosmin reached the peak value of 7100ngL-1 on 3 July, which was the highest value ever reported. The average geosmin production potential for A. spiroides cells was approximately 0.1pgcell-1, which was also very high and 85-97% of geosmin was found within the cells and in addition the dissolved geosmin did not increase even during the cyanobacterial decay period. In addition to odor metabolites, three microcystin variants MC-LR, MC-RR, MC-YR and anatoxin-a, most of which were intracellular, were detected, with MC-RR being the dominant cyanotoxin. The highest cyanotoxin concentrations were: dissolved: MC-RR 1.56μgL-1, MC-YR 0.066μgL-1, MC-LR 0.544μgL-1, anatoxin-a 0.106μgL-1; intracellular: MC-RR 70.1μgL-1, MC-YR 3.76μgL-1, MC-LR 24.6μgL-1, anatoxin-a 0.184μgL-1, and these occurred on 2 July. The correlation between geosmin and A. spiroides was excellent (R2=0.912), however the correlation between anatoxin-a concentrations and Anabaena densities and between MCs concentrations and Microcystis densities was not as strong. This study demonstrated the relatively complex requirement for monitoring cyanobacterial blooms in this lake in China, where both the range of odors and cyanotoxins can be produced in concentrations which can change rapidly over a short time along with the bloom composition. It also demonstrated that both odor compounds and cyanotoxins should be considered in terms of the potential hazard to public water supply when a bloom was dominated by Anabaena and Microcystis occurs. © 2010 Elsevier B.V.

Humpage A.R.,Australian Water Quality Center | Magalhaes V.F.,Federal University of Rio de Janeiro | Froscio S.M.,Australian Water Quality Center
Analytical and Bioanalytical Chemistry | Year: 2010

The paralytic shellfish poisoning toxins (PSTs) were, as their name suggests, discovered as a result of human poisoning after consumption of contaminated shellfish. More recently, however, the same toxins have been found to be produced by freshwater cyanobacteria. These organisms have worldwide distribution and are common in our sources of drinking water, thus presenting another route of potential human exposure. However, the regulatory limits for PSTs in drinking water are considerably lower than in shellfish. This has increased the need to find alternatives to the mouse bioassay, which, apart from being ethically questionable, does not have a limit of detection capable of detecting the PSTs in water at the regulated concentrations. Additionally, the number of naturally occurring PSTs has grown substantially since saxitoxin was first characterised, markedly increasing the analytical challenge of this group of compounds. This paper summarises the development of chromatographic, toxicity, and molecular sensor binding methodologies for detection of the PSTs in shellfish, cyanobacteria, and water contaminated by these toxins. It then summarises the advantages and disadvantages of their use for particular applications. Finally it recommends some future requirements that will contribute to their improvement for these applications. © 2010 Springer-Verlag.

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