Mixture risks threaten water quality: the European Collaborative Project SOLUTIONS recommends changes to the WFD and better coordination across all pieces of European chemicals legislation to improve protection from exposure of the aquatic environment to multiple pollutants

Abstract

Evidence is mounting that chemicals can produce joint toxicity even when combined at levels that singly do not pose risks. Environmental Quality Standards (EQS) defined for single pollutants under the Water Framework Directive (WFD) do not protect from mixture risks, nor do they enable prioritization of management options. Despite some provisions for mixtures of specific groups of chemicals, the WFD is not fit for purpose for protecting against or managing the effects of coincidental mixtures of water-borne pollutants. The conceptual tools for conducting mixture risk assessment are available and ready for use in regulatory and risk assessment practice. Extension towards impact assessment using cumulative toxic unit and mixture toxic pressure analysis based on chemical monitoring data or modelling has been suggested by the SOLUTIONS project. Problems exist in the availability of the data necessary for mixture risk assessments. Mixture risk assessments cannot be conducted without essential input data about exposures to chemicals and their toxicity. If data are missing, mixture risk assessments will be biassed towards underestimating risks. The WFD itself is not intended to provide toxicity data. Data gaps can only be closed if proper feedback links between the WFD and other EU regulations for industrial chemicals (REACH), pesticides (PPPR), biocides (BPR) and pharmaceuticals are implemented. Changes of the WFD alone cannot meet these requirements. Effect-based monitoring programmes developed by SOLUTIONS should be implemented as they can capture the toxicity of complex mixtures and provide leads for new candidate chemicals that require attention in mixture risk assessment. Efforts of modelling pollutant levels and their anticipated mixture effects in surface water can also generate such leads. New pollutant prioritization schemes conceived by SOLUTIONS, applied in the context of site prioritization, will help to focus mixture risk assessments on those chemicals and sites that make substantial contributions to mixture risks. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

A holistic approach is key to protect water quality and monitor, assess and manage chemical pollution of European surface waters

“…The diagnostic methods are summarized and characterized in the other SOLUTIONS Policy Briefs. For example, methods can be selected for early-stage exploratory assessments on the presence of chemicals [19], via refined component-and effect-based diagnostic approaches of impacts [20,21] to specific biological quality elements [22] and the ecological status [13], up till integrated modeling [23]. The methods cover the full array of the DPSIR-causal approach (Fig.…”

The RiBaTox web tool: selecting methods to assess and manage the diverse problem of chemical pollution in surface waters

“…Amongst others, this involves an analysis of pressures and impacts [6] and the classification of the chemical and ecological status on the basis of chemical and ecological monitoring data and the quality standards [7,8]. The current approach does not sufficiently cover the chemical pollution problem, as both societal concerns and scientific research asks consideration of far more chemicals and their mixtures [9,10]. The results of the research encompass a suite of tools to characterize the pollution problem, as described in associated Policy Briefs of the SOLUTIONS-project.…”

“…The web tool supports the recommended changes of chemical pollution protection, assessment and management that have been proposed in associated Policy Briefs (e.g. on using holistic approaches considering chemical pollution from a water-system level point of view [5], for vastly more chemicals and their mixtures [10][11][12], via both monitored and modelled environmental concentrations of chemicals [15], with early consideration of the 'solution space' [16,17], and with associated improvements on, e.g. monitoring data management [18]).…”

Solutions for present and future emerging pollutants in land and water resources management. Policy briefs summarizing scientific project results for decision makers

“…A better protection of water quality from mixture risks requires not only conceptual and technical innovation in monitoring and assessment but may also demand for changes to the WFD and a better coordination across the pieces of European chemical legislation [19] as well as an increase in coherence, cooperation and cross-compliance of chemicals and water regulations [20]. To finally meet the European policy goals for achieving a sustainable, nontoxic environment, European collaborative environmental research should be strengthened to mobilize the extensive European research capacities and competences required to address the enormous challenges we are facing to reduce modern society's footprints in general and toxic risks in particular [21].…”