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Port Adelaide, Australia

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. Source

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. Source

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. Source

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. Source

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. Source

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