Applicability of Chronic Multiple Linear Regression Models for Predicting Zinc Toxicity in Australian and New Zealand Freshwaters.

Bioavailability models, for example, multiple linear regressions (MLRs) of water quality parameters, are increasingly being used to develop bioavailability-based water quality criteria for metals. However, models developed for the Northern Hemisphere cannot be adopted for Australia and New Zealand without first validating them against local species and local water chemistry characteristics. We investigated the applicability of zinc chronic bioavailability models to predict toxicity in a range of uncontaminated natural waters in Australia and New Zealand. Water chemistry data were compiled to guide a selection of waters with different zinc toxicity-modifying factors. Predicted toxicities using several bioavailability models were compared with observed chronic toxicities for the green alga Raphidocelis subcapitata and the native cladocerans Ceriodaphnia cf. dubia and Daphnia thomsoni. The most sensitive species to zinc in five New Zealand freshwaters was R. subcapitata (72-h growth rate), with toxicity ameliorated by high dissolved organic carbon (DOC) or low pH, and hardness having a minimal influence. Zinc toxicity to D. thomsoni (reproduction) was ameliorated by both high DOC and hardness in these same waters. No single trophic level-specific effect concentration, 10% (EC10) MLR was the best predictor of chronic toxicity to the cladocerans, and MLRs based on EC10 values both over- and under-predicted zinc toxicity. The EC50 MLRs better predicted toxicities to both the Australian and New Zealand cladocerans to within a factor of 2 of the observed toxicities in most waters. These findings suggest that existing MLRs may be useful for normalizing local ecotoxicity data to derive water quality criteria for Australia and New Zealand. The final choice of models will depend on their predictive ability, level of protection, and ease of use. Environ Toxicol Chem 2023;42:2614-2629. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Probabilistic risk assessment of mine-derived copper in the Ok Tedi/Fly River, Papua New Guinea.

The Ok Tedi mine discharges waste rock and tailings into the Ok Tedi River in Papua New Guinea. This has resulted in elevated copper concentrations throughout the Ok Tedi/Fly River system, which can potentially impact aquatic biota. Ten years of measured copper and toxicity monitoring data were used to assess the risk of chronic effects from the mine-derived copper. Cumulative probability plots of dissolved and labile copper were compared to a species sensitivity distribution (SSD) of published copper toxicity data for four regions of the river. The Cu-SSD was used to estimate the risk of chronic effects to aquatic organisms in the Ok Tedi/Fly River at a range of potential copper exposure scenarios. The risk to species at the median labile copper concentration for each region showed a gradient effect with distance downstream from the mine and only the most sensitive (0.2-11%) species were at risk. There were copper exceedances of the region-specific guideline values (GV) and default guideline value (DGV) 88% and 74% of the time, respectively, in the Ok Tedi region (closest to the mine) and this is considered a high risk of chronic effects. Measured copper concentrations in the middle Fly River, lower Fly River (farthest downstream of the mine) and the river at Kiunga (reference site) exceeded the region-specific GVs and DGVs less frequently to rarely and present a lower risk of chronic effects from copper. The risk was supported using toxicity tests with the local microalgal species Chlorella sp. Comparison of recent (2010-2020) and historical (1996-2004) copper monitoring data from the Ok Tedi/Fly River indicates a decrease in the labile copper concentrations (30-76%) at key sites from impacted regions and a subsequent decrease in risk. This coincides with improved mining practices aimed at reducing the copper load into the Ok Tedi/Fly River.

Estimation of policy-relevant reference conditions throughout national river networks.

A method for objectively estimating reference states for suspended fine sediment (turbidity) is presented. To be fit for water policy development and implementation the method had to satisfy four requirements: (1) the method must not be dependent on data from minimally-disturbed reference sites; (2) the method must facilitate characterization of reference states throughout heterogeneous river networks, given patchy data; (3) the classification of reference states must be relevant and legitimate to end-users; (4) the method should provide several classifications of reference states at different spatial resolutions allowing selection of the resolution yielding the most parsimonious classification of reference states throughout the network. Implementing the method involves two stages: (1) Development of a river classification based on sediment supply and retention regimes (defining 'turbidity classes') at multiple spatial resolutions. (2) At each resolution, for each turbidity class, estimation of a reference state based on relationships between turbidity and anthropogenic stressors, then objective selection of the resolution yielding the most parsimonious classification of reference states throughout the network. Implementing the method requires a river network GIS and turbidity data within classes, preferably from monitoring sites spanning the domains of the anthropogenic stressor variables used for model-based estimation of reference states.•A method is presented for estimating reference states for suspended fine sediment (turbidity) throughout spatially heterogeneous river networks.•Development of the method was guided by the requirements of policy analysts during reform of water policy in New Zealand.•The method presented was used to develop fine sediment regulatory thresholds of national water policy.

Localizando a criticidade na política: a contínua luta por justiça social na agenda da educação física escolar / Locating criticality in policy: the ongoing struggle for a social justice agenda in school physical education / Ubicando la criticidad en la política: la continua lucha por justícia social en la agenda de la educación física escolar

Há um sentimento de promessa não realizada quando se analisa o progresso do projeto crítico da Educação Física desde a virada da segunda década do século XXI. Estudos de qualidade continuam a emergir em torno da pedagogia crítica da Educação Física, evidenciando o prolongado comprometimento com sua promessa de fornecer aos aprendizes recursos pessoais e intelectuais que são necessários na orientação de produtivos futuros sadios num mundo cada mais complexo. Neste artigo nós discutimos destacados exemplos de investigações contemporâneas que demonstram as contínuas lutas em contextos práticos e revisita barreiras que continuam a restringir as aspirações dos estudos críticos. Focando na Educação Física como uma prática cultural e curricular nas escolas australianas, nós damos primazia aos modos pelos quais políticas diretivas podem ser melhor mobilizadas para capacitar a agenda crítica

There is a sense of unfulfilled promise as one reflects on the progress of the critical project in Physical Education (PE) at the turn of the second decade of the 21st century. Quality scholarship continues to emerge around critical pedagogy in PE, evidencing sustained commitment to its promise to provide learners with personal and intellectual resources needed in navigating productive healthy futures in an increasingly complex world. In this paper we discuss select examples of contemporary research to demonstrate ongoing struggles in practice-based contexts and revisit barriers that continue to restrict the translational aspirations of critical scholars. Focusing on PE as a cultural and curriculum practice in Australian schools, we give primacy to the ways in which policy directives might be better mobilised to enable the critical agenda

Hay un sentimiento de promesa no cumplida cuando se analiza el progreso del proyecto crítico de la Educación Física desde el giro de la segunda década del siglo XXI. Estudios de calidad continúan a emerger en torno a la pedagogía crítica de la Educación Física, evidenciando el prolongado compromiso con su promesa de ofrecer a los aprendices recursos personales e intelectuales que son necesarios en la orientación de productivos futuros saludables en un mundo cada vez más complejo. En ese artículo discutimos destacados ejemplos de investigaciones contemporáneas que demuestran las continuas luchas en contextos prácticos y revisita barreras que continúan restringiendo las aspiraciones de los discursos críticos. Con foco en la Educación Física como una práctica cultural y curricular en las escuelas australianas, priorizamos los modos por los cuales políticas directivas pueden ser mejor movilizadas para capacitar la agenda crítica

Validation of the nickel biotic ligand model for locally relevant species in Australian freshwaters.

Australian freshwaters have relatively low water hardness and different calcium (Ca) to magnesium (Mg) ratios compared with those in Europe. The hardness values of a substantial proportion of Australian freshwaters fall below the application boundary of the existing European nickel biotic ligand models (Ni BLMs) of 2 mg Ca/L. Toxicity testing was undertaken using Hydra viridissima to assess the predictive ability of the existing Ni BLM for this species in extremely soft waters. This testing revealed an increased competitive effect of Ca and Mg with Ni for binding to the biotic ligand in soft water (<10 mg CaCO3 /L) than at higher water hardness. Modifications were made to the Ni BLM by increasing the binding constants for Ca and Mg at the biotic ligand to account for softer waters encountered in Australia and the more important competitive effect of Ca and Mg on Ni toxicity. To validate the modified Ni BLM, ecotoxicity testing was performed on 5 Australian test species in 5 different natural Australian waters. Overall, no single water chemistry parameter was able to indicate the trends in toxicity to all of the test species. The modified Ni BLMs were able to predict the toxicity of Ni to the test species in the validation studies in natural waters better than the existing Ni BLMs. The present study suggests that the overarching mechanisms defining Ni bioavailability to freshwater species are globally similar and that Ni BLMs can be used in all freshwater systems with minor modifications. Environ Toxicol Chem 2018;37:2566-2574. © 2018 SETAC.

How do aquatic communities respond to contaminants? It depends on the ecological context.

Context dependency refers to variation in ecological patterns and processes across environmental or spatiotemporal gradients. Research on context dependency in basic ecology has focused primarily on variation in the relative importance of species interactions (e.g., competition and predation) among communities. In this Focus article, the authors extend this concept to include variation in responses of communities to contaminants and other anthropogenic stressors. Because the structure of communities varies naturally along environmental gradients, their responses to contaminants may also vary. Similar to the way in which aquatic toxicologists assess abiotic factors associated with contaminant bioavailability, observations about context dependency could be used to test hypotheses about ecological mechanisms responsible for differences in sensitivity among communities.

Enhancing the ecological significance of sediment contamination guidelines through integration with community analysis.

The underlying basis of sediment quality guidelines needs to be accepted both by the international scientific community and socially before they can be of use. Increasingly, this means that just saying that a certain number of species will be affected is not sufficient. Instead guidelines need to be related to changes in community composition and predicted changes in biodiversity and ecosystem function. This study derived guidelines for copper, zinc, and lead, from field-based SSDs, that predicted a 50% decrease in abundance of 5% of the taxa, well below present management guidelines. However, a multivariate model of effect demonstrated considerable changes in community composition occur at levels below these derived guidelines. Changes in the degree of rarity also occurred signaling potential changes to meta-community structure and resilience of the region. Furthermore, the most sensitive taxa indicated by the multivariate analysis were frequently of large size and those likely to affect oxygen, carbon, and nutrient exchanges between the water column and the seafloor, leading to ecological effects beyond the obvious change in composition. We suggest that guidelines should preferentially be field derived, backed where possible by experimental work. Community and functional responses should be calculated, from the same field studies, and explicitly mentioned whenever the guidelines are used to allow environmental costs to be more realistically determined.

In situ methods of measurement--an important line of evidence in the environmental risk framework.

A tiered framework provides a structured approach to assess and manage risk and underpins much of the legislation concerning chemicals and environmental management. Management decisions regarding appropriate controls can have high cost implications to the regulated community. The risk framework provides an evidence-based approach to reduce uncertainty in decision making. Traditional assessment is heavily dependent on laboratory-generated toxicity test data and estimations of exposure and effect. Despite many well documented demonstrations of in situ methodologies, they are rarely used by regulators to help improve assessment or to validate risk. Emerging legislation puts greater emphasis on environmental outcomes and represents a significant shift from the reliance on chemical measures alone toward biological responses that improve assessment and demonstrate ecological benefit. Diagnostic methods, that could include in situ-based measures, will help assess and manage environments failing to achieve good status and it is likely that a weight of evidence approach will be needed to help inform management decisions. The potential application of such measures in the risk framework is reviewed in the context of current and emerging legislation concerning chemicals. Effect measures on the basis of in situ methods provide an alternative line of evidence and can help reduce uncertainty in decision making. Criteria are presented to help select appropriate methods in a multiple-line, weight of evidence approach.