The use of simulated whole effluents in toxicity assessments: A review of case studies from reverse osmosis desalination plants

Seawater desalination is an increasingly common means to meet the demand for freshwater. Resulting wastewater discharges can, however, impact biota of the surrounding environment. Concern exists that interactive effects specific to the outputs of each desalination plant may result in unique impacts difficult to predict by studying existing plants or assessing the effects of individual chemicals found in waste streams. Given this, we highlight an alternative approach to assess potential toxicity of desalination outfalls. Specifically, we review three recent case studies from Australia in which simulated whole effluents were used in toxicity assessments before desalination plants were constructed. This approach enabled potential toxic effects of wastewater to be considered before the plants became operational and, in one case, even facilitated consideration of potential effects of different treatment processes and suppliers. As in many whole effluent toxicity assessments, the time required for testing and restricted range of species considered were limitations. Given the benefits of this method, however, the use of simulated whole effluents is a development that could facilitate an improved capacity to forecast impacts of proposed desalination plants

No harm, no foul?: Expert views on the future direction of marine antibiofouling technologies

The colonisation of submerged surfaces by marine fouling organisms is a global problem with impacts ranging from clogged pipelines and aquaculture nets through to hull fouling that increases fuel costs and green-house gas emissions and provide potential habitats for invasive species. Marine antibiofouling techniques, such as copper plates on ships and functional coatings that release toxic biocides, were historically developed in order to reduce the frequency and expense of the physical removal of fouling organisms. For a time the solution was thought to be tributyltin self-polishing coatings, but these were later proven to be detrimental to the marine environment and subsequently banned. Today, the 'state-of-the-art' general-use coatings are based on the release of biocidal copper and booster biocides, but environmental concerns exist regarding their impacts on marine life and future legislation may put restrictions on their use. While non-biocide based alternatives include non-stick or foul-release coatings, these generally work best on fast moving vessels with little stationary time, even if recent developments seem to reduce this demand on speed. We utilised a targeted questionnaire to a range of experts that work with, or are affected by, marine anti-biofouling to assess their views about potential antifouling technologies of the future. The paper provide insights into the expectations and demands that need to be addressed in development and implementation of future marine anti-biofouling technologies and indicate how those views differ between professional roles

Cryptic sympatric species across the Australian range of the global estuarine invader Ficopomatus enigmaticus (Fauvel, 1923) (Serpulidae, Annelida)

Ficopomatus enigmaticus (Fauvel, 1923) is a reef-building serpulid polychaete that has invaded estuaries worldwide, causing environmental and economic harm. Although Australia has long been suggested as a place of origin for the species, this remains unclear. We tested for genetic patterns across the range of F. enigmaticus in southern Australia, predicting that if the species is an Australian native, it would show evidence of (east-west) phylogeographic patterns often observed in native marine species in southern Australia. Unexpectedly, concordant patterns from mitochondrial (Cyt B) sequencing and nuclear marker (iSSR) profiles suggested the presence of at least three genetic groups (putative species), not distributed simply as “east” or “west”. Two common (and closely related) groups were present across Australia and were often found together in the same aggregations. A third group was only found in southeast Australia and was morphologically similar to F. uschakovi (Pillai, 1960), a species previously reported from tropical areas. The discovery of multiple cryptic species with overlapping ranges means that more work is needed to resolve whether any of the F. enigmaticus sensu lato group has an Australian origin and to determine how they are related to invasive populations of F. enigmaticus elsewhere

Integration of environmental aspects in modelling and optimisation of water supply chains

Climate change becomes increasingly more relevant in the context of water systems planning. Tools are necessary to provide the most economic investment option considering the reliability of the infrastructure from technical and environmental perspectives. Accordingly, in this work, an optimisation approach, formulated as a spatially-explicit multi-period Mixed Integer Linear Programming (MILP) model, is proposed for the design of water supply chains at regional and national scales. The optimisation framework encompasses decisions such as installation of new purification plants, capacity expansion, and raw water trading schemes. The objective is to minimise the total cost incurring from capital and operating expenditures. Assessment of available resources for withdrawal is performed based on hydrological balances, governmental rules and sustainable limits. In the light of the increasing importance of reliability of water supply, a second objective, seeking to maximise the reliability of the supply chains, is introduced. The epsilon-constraint method is used as a solution procedure for the multi-objective formulation. Nash bargaining approach is applied to investigate the fair trade-offs between the two objectives and find the Pareto optimality. The models' capability is addressed through a case study based on Australia. The impact of variability in key input parameters is tackled through the implementation of a rigorous global sensitivity analysis (GSA). The findings suggest that variations in water demand can be more disruptive for the water supply chain than scenarios in which rainfalls are reduced. The frameworks can facilitate governmental multi-aspect decision making processes for the adequate and strategic investments of regional water supply infrastructure

Optimisation approaches for the synthesis of water treatment plants

Efficient water treatment design has progressively been growing in importance as the usage of water resources increases with population rise and industrial development. Their availability has been reduced with the more evident effects of climate change. Addressing this challenge necessitates more and efficient purification plants which can be realised by optimal design at conceptual stage. In this work, a mixed integer nonlinear programming (MINLP) model for the synthesis and optimisation of water treatment processes is proposed. Due to its numerous non-linearities and consequently, its non-stability, various linearisation, approximation and reformulation techniques have been implemented. Consequently, two improved formulations are derived, i.e. a partially linearised MINLP (plMINLP) and a mixed integer linear fractional programming (MILFP) models. The applicability of the mathematical formulations are investigated in case studies of seawater desalination and surface water treatment for the production of potable water. Finally, the models performance is analysed and compared against each other

Sperm motility of oysters from distinct populations differs in response to ocean acidification and freshening

Species' responses to climate change will reflect variability in the effects of physiological selection that future conditions impose. Here, we considered the effects of ocean acidification (increases in pCO2; 606, 925, 1250 µatm) and freshening (reductions in salinity; 33, 23, 13 PSU) on sperm motility in oysters (Crassostrea gigas) from two populations (one recently invaded, one established for 60+ years). Freshening reduced sperm motility in the established population, but this was offset by a positive effect of acidification. Freshening also reduced sperm motility in the recently invaded population, but acidification had no effect. Response direction, strength, and variance differed among individuals within each population. For the established population, freshening increased variance in sperm motility, and exposure to both acidification and freshening modified the performance rank of males (i.e. rank motility of sperm). In contrast, for the recently invaded population, freshening caused a smaller change in variance, and male performance rank was broadly consistent across treatments. That inter-population differences in response may be related to environmental history (recently invaded, or established), indicates this could influence scope for selection and adaptation. These results highlight the need to consider variation within and among population responses to forecast effects of multiple environmental change drivers

Realising a vision of no net loss through marine biodiversity offsetting in Australia

Biodiversity offsets are increasingly used in policy frameworks to regulate the environmental impacts of development including projects located in marine environments. Scientific knowledge gaps and other practical challenges have necessitated flexibility concerning the manner in which key offsetting principles are implemented in policy frameworks relevant to such environments. The potential trade-off of such flexibility is that consequent marine offsetting practice may not be compatible with the ultimate objective of no net loss of biodiversity. Here we present a systematic review of marine and coastal development projects in Australia, examining how offsetting is being implemented in practice. Forty-two (42) projects were assessed, predominantly located in Queensland and Western Australia and associated with the development and operation of ports. We find that application of key biodiversity offsetting principles (e.g. ecological equivalence) was frequently incomplete or absent. For approximately 50% of reviewed projects we were unable to identify public information concerning how offsetting requirements were established. The current environmental outcomes of marine biodiversity offsetting in Australia are unclear but there are indications that it is unlikely to achieve no net loss of biodiversity

Data-Driven Approaches to Measuring a Social Licence to Operate

Companies in the energy and resources sectors often conduct surveys to understand their acceptance within the community. Such surveys generate rich data, yet sometimes key insights can be missed using conventional plots of average responses for each question. Here, we investigated how multivariate statistics might be used to analyse and communicate information from a Social Impact Assessment of an Australian coal seam gas (LNG) project. The drivers of community acceptance were complex and impacts with the greatest/least average scores were not necessarily those most correlated with acceptance. For example, while housing affordability and availability were consistently seen as negative impacts, individuals’ views on employment and economic opportunities were better correlated with acceptance - even though these were, on average, not seen as positive or negative impacts of development. Consistent with previous statistical (path analysis) assessment of the same data, a perceptual map based on r-mode analyses suggested relational factors such as trust and perceptions of good environmental regulation were the most important drivers of acceptance of the LNG industry. Community response maps created using q-mode analyses represented the diversity of opinions for multiple drivers, highlighting that “the community” is not a uniform entity. For example, although those involved in (non-LNG) industry generally reported greater levels of acceptance and trust than others in the community, there were still some individuals within this group that did not trust or accept the LNG industry. While a SLO can be complex and is likely to constantly change, our study shows multidimensional scaling may be a useful tool for communicating social survey results to engineers and managers in a way that encapsulates some of the important details of a SLO, yet still be intuitive enough to include in reporting dashboards

Nonequilibrium Conditions Explain Spatial Variability in Genetic Structuring of Little Penguin (Eudyptula minor)

Factors responsible for spatial structuring of population genetic variation are varied, and in many instances there may be no obvious explanations for genetic structuring observed, or those invoked may reflect spurious correlations. A study of little penguins (Eudyptula minor) in southeast Australia documented low spatial structuring of genetic variation with the exception of colonies at the western limit of sampling, and this distinction was attributed to an intervening oceanographic feature (Bonney Upwelling), differences in breeding phenology, or sea level change. Here, we conducted sampling across the entire Australian range, employing additional markers (12 microsatellites and mitochondrial DNA, 697 individuals, 17 colonies). The zone of elevated genetic structuring previously observed actually represents the eastern half of a genetic cline, within which structuring exists over much shorter spatial scales than elsewhere. Colonies separated by as little as 27 km in the zone are genetically distinguishable, while outside the zone, homogeneity cannot be rejected at scales of up to 1400 km. Given a lack of additional physical or environmental barriers to gene flow, the zone of elevated genetic structuring may reflect secondary contact of lineages (with or without selection against interbreeding), or recent colonization and expansion from this region. This study highlights the importance of sampling scale to reveal the cause of genetic structuring

Low sensitivity of reproductive life-stages in the Pacific oyster (Crassostrea gigas) to abamectin

Hard surfaces submerged in the marine environment often become colonised by macro-organisms unless the surfaces have some form of biofouling protection. While protective paints that contain tributyltin or copper work well to prevent biofouling, release of these materials into the environment has been shown to have wider negative impacts. Consequently, new low-release antifouling paints are being developed with alternative active ingredients, such as avermectins, yet little is known about their potential effects on non-target organisms in marine environments. Here we investigated the toxicity of a key avermectin, specifically abamectin, on several aspects of reproduction (sperm motility, fertilisation success, early larval development) in the Pacific oyster, Crassostrea gigas. Oyster reproduction was generally insensitive to the low concentrations of abamectin, although greater concentrations of abamectin did negatively affect all three endpoints – LOECs were 1000 μg l−1, 500 μg l−1, and 100 μg l−1 abamectin for sperm motility, fertilisation success, and larval development, respectively. A similar pattern was found in the EC50s of the three endpoints (mean ± SE) 934 ± 59 μg l−1, 1076.26 ± 725.61 μg l−1, and 140 ± 78 μg l−1 abamectin (sperm motility, fertilisation success, and larval development, respectively). Together, these results clearly indicate that of the three endpoints considered, larval development was more sensitive to abamectin (lower LOEC, EC50) than fertilisation success and sperm motility. Although more data are needed from a wider range of marine species and environments to fully assess potential toxicity effects on non-target organisms, our results highlight the potential utility of abamectin in low-release antifouling paints