The growing consumption of materials in our digital society represents an ever increasing waste stream containing novel and complex mixtures of chemicals, including many oxyanion forming contaminants (OFCs, e.g. As, B, Cr, Mo, Sb, V, Se, Sb, Te, etc.) that threaten freshwater security. Current industrial innovations (e.g. electric vehicles, domestic power storage, the internet of things) and policy drivers (e.g. acceleration of Energy from Waste (EfW) in UK/EU) will increase future usage of these elements, which gives rise to potential releases from cycles of production and consumption into the environment. Ecosystem health in lakes and rivers are underpinned by complex relationships between environmental drivers (e.g. nutrients, weather, contaminants etc.), and can be highly degraded by inputs of OFCs such as P and As. These effects can be persistent over decades as a result of interactions with sediments and biota under varying pH and redox. This project will produce a large scale assessment of key environmental pathways for key OFCs and combine field and experimental approaches to comprehensively study the effects of established OFCs across ecological scales (i.e. from molecular processes to impacted ecosystems). Data from these approaches can be used to inform ecotoxicological risk assessments and predictive models, with which future management and policy approaches, developed to mitigate the effects of future waste stream scenarios, can be evaluated.
OFCs can be released from a wide range of industrial sources, including EfW incinerator ashes, petroleum combustion residues, and many different mining and metal processing wastes (e.g. iron and aluminium ore processing). A common factor across all sources is the occurrence of multiple different oxyanion contaminants present in elevated concentrations, which are often then readily mobilised in associated leachates and leaching tests [1-2]. This has helped define a short list of oxyanion contaminants, including toxic OFCs such as As, V, and Se for inclusion in this project. Specific objectives:
1. Utilising available data and literature, develop a conceptual model of OFE risk including waste streams, critical exposure pathways, transformation processes, ecosystem effects and risk assessment from catchment to global scales, with a focus on the UK scale. 2. Investigation of actively polluted rivers and lakes, to establish relationships between OFE composition and behaviour in the field, catchment scale flux models, and net ecosystem effects in control versus impacted sites. 3. Produce experimental and molecular level data to quantify the drivers of interactions between OFEs (as individual components and mixtures) and other chemical components of receiving waters to define the potential for significant ecotoxicological effects in affected environments.