Time filter

Source Type

Port Adelaide, Australia

Liu Z.,CAS Research Center for Eco Environmental Sciences | Yan X.,CAS Research Center for Eco Environmental Sciences | Drikas M.,South Australia Water Corporation | Zhou D.,Beijing Waterworks Group | And 3 more authors.
Journal of Environmental Sciences | Year: 2011

The contamination of surface and ground water by bentazone has attracted increasing global concern in recent years. We conducted a detailed investigation using MIEX resin to eliminate bentazone from waters. Batch experiments were carried out to evaluate the effect of process parameters, such as retention time, resin amount, and initial pesticide concentration, on removal efficiency of bentazone. Results showed the sorption process was fast and bentazone could be efficiently removed in 30 minutes. The kinetic process of bentazone sorption on MIEX resin was well described by pseudo second-order model and intraparticle diffusion was the rate controlling step. The MIEX resin possessed the highest sorption capacity of 0.2656 mmol/mL for bentazone according to Langmuir fitting. Bentazone is a hydrophobic ionizable organic compound, and both ionic charge and hydrophobic aromatic structure governed the sorption characteristics on MIEX resin. The different removal efficiencies of ionic and non-ionic pesticides, combined with the charge balance equations of bentazone, SO4 2-, NO3 - and Cl-, indicated that removal of bentazone using MIEX resin occurred primarily via ion exchange. © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

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.

Zamyadi A.,Ecole Polytechnique de Montreal | McQuaid N.,Ecole Polytechnique de Montreal | Dorner S.,Ecole Polytechnique de Montreal | Bird D.F.,University of Quebec at Montreal | And 4 more authors.
Journal - American Water Works Association | Year: 2012

The applications of in vivo probes that can detect the fluorescence of cyanobacterial phycocyanin are emerging and widely used for cyanobacterial detection in source waters. The objectives of this project were to study the sources of interferences involved with the readings of five probes (three commercially available probes and two prototype probes) using laboratory cultures and field samples. To compare the direct readings of different probes, the probe readings were presented in the form of a biovolume equivalent of cyanobacteria. Inorganic turbidity and the presence of algal biomass interfered with probe readings. A correction factor was developed for the cyanobacteria probes using simultaneous chlorophyll a measurements. The field data demonstrate that the potential underestimation of cyanobacterial biomass that corresponds to alert levels is a major issue with the application of in vivo probes. These alert levels are used to trigger monitoring and management actions. This study shows that the correlation between a probe's reading and cell count is almost meaningless, and that the correlation to biovolume is a relevant option for management purposes. Results show that probe users should be fully aware of the sources of interferences when applying and interpreting the results. In addition, the authors offer a novel procedure that corrects for chlorophyll a interference. © 2012 American Water Works Association.

Discover hidden collaborations