Cumulative hazard and risk assessment of complex mixtures and multiple stressors (MixRisk)

Organisms in the aquatic environment are exposed to mixtures of pollutants, natural stressors and stressors arising from global climate changes. Despite in-depth knowledge of biological effects of single pollutants and stressors, the combined effect of exposures to complex mixtures and multiple stressors are often not known, and even more rarely characterised. The MixRisk project aims to implement and evaluate cumulative hazard and risk assessment of complex mixtures of aquatic pollutants and multiple stressors under Norwegian environmental conditions. It will pinpoint critical exposure scenarios, identify risk drivers and critically explore different hazard and risk assessment approaches. A major goal of the project will be to provide recommendations for how to best perform cumulative hazard and risk assessment. A collaborative effort between 7 partners from Norway, UK and USA have addressed these challenges by assessing the collective contribution of pollutants, ultraviolet and ionizing radiation on marine organisms under typical Norwegian exposure scenarios along the coastline from Oslo in the east (urban pollution), Lillesand in the south (Rural pollution), Sørfjorden in the west (industrial pollution) and Svalbard in the North (Arctic pollution). Scientific development in the project period have included improvement of existing biological and chemical analysis methods, collection and quality assurance of data from various Norwegian exposure scenarios and further development of an exposure, impact and risk assessment database (NIVA RAdb, www.niva.no/radb). Cumulative risk assessment of 3 exposure scenarios are finalized, probabilistic distributional assessment tools for exposure have been developed, experimental evaluation of model predictions of combined toxicity of eco-relevant chemical mixtures and selected non-chemical stressors (e.g. UVB) have been conducted in a laboratory with a crustacean (copepod) model. The results from the different experimental and computational approaches reveal that use of combined toxicity models for additivity (e.g. concentration-addition) provide a fair approximation in initial tiers of risk assessment, but lack of high quality effect data for chemical and/or non-chemical stressors limit the applicability of more detailed cumulative risk assessment for organism and exposure scenarios relevant for Norwegian coastal regions. Increased access to concise effect data for representative marine organisms is expected to strengthen risk predictions and reduce uncertainty. Production of concise effects data through experimental studies and/or development of prediction models to extrapolate toxicity data from typical freshwater to marine species is anticipated to support both evolution and evaluation of such models. Its anticipated that increase in the experimental knowledge of how non-chemical interactions affect the combined effects of multiple-stressors will also strengthen such predictions. The project has hosted 3 PhD’ and one post doc, whereof 1 PhD has successfully completed their studies and the rest is in their final phases of education. Key researchers in the project have presented concepts and methodological approaches at several scientific meetings and have published scientific papers on the subject in different scientific journals.

Virkninger: Prosjektet har muliggjort storskala bruk av eksponeringsdata fra overvåkingsstudier i prediksjon av kumulativ (samlet risiko) for ulike miljøstressorer. Arbeidet har i stor grad vært fokusert på miljøgifter (eks. metaller og organiske stoffer), men har også vurdert bidrag fra stråling (radioaktiv stråling og UV-stråling). Prosjektarbeidet har medført videreutvikling av metodikk og verktøy, sikret en samarbeidsplattform for yngre forskere i rekrutteringsfasen (1 norsk phD fullfinansiert av Prosjektet, 2 engelske phD studenter samfinansiert av prosjektet og en post doc fullfinansiert av prosjektet) og videreutviklet et nasjonalt og internasjonalt forskernettverk innen området. Effekter: prosjektet har sikret videreutvikling av verktøy for vurdering av samvirkeffekter som i større grad inngår i prosjektpartnernes prosjekt, og som bidrar som en av flere verktøy i HEU prosjektet PARC-European Partnership for Risk Assessment of Chemicals (https://www.anses.fr/en/content/european-partnership-assessment-risks-chemicals-parc). Verktøyene og kompetansen utviklet benyttes også i dag i risikovurdering av plantevernmidler som del av Program for Jord- og vannovervåking i landbruket, JOVA (https://www.nibio.no/tema/miljo/jord-og-vannovervaking-i-landbruket). Forskningsresultatene antyder at tilsvarende metoder kan ha anvendelse i samlet miljøpåvirkning i andre forvaltningsorienterte overvåkingsprosjekt der kjemikalier og andre miljøstressorer måles.

Organisms in the aquatic environment are exposed to mixtures of pollutants,natural stressors and stressors arising from global climate changes. Despite in-depth knowledge of biological effects of single pollutants and stressors,the combined effect of exposures to complex mixtures and multiple stressors are often not known, and even more rarely characterised. Advancement of predictive modelling approaches currently allow assessment of combined toxicity of defined mixtures under controlled laboratory conditions, but have only to a limited degree been implemented in cumulative risk assessment of mixtures and multiple stressors under ecologically relevant exposure scenarios. The project aims to implement and evaluate cumulative hazard and risk assessment of complex mixtures of aquatic pollutants and multiple stressors under Norwegian environmental conditions. It will pinpoint critical exposure scenarios, identify risk drivers and critically explore different hazard and risk assessment approaches. A major goal of the project will be to provide recommendations for how to best perform cumulative hazard and risk assessment. These objectives will be achieved by 1) identifying relevant Norwegian exposure scenarios representing a risk to aquatic organisms, 2)experimentally assess combined toxicity of relevant stressors in a multi-trophic suite of regulatory relevant toxicity tests, 3) assess whether these experimental and theoretical approaches can be applied to multiple stressors, and 4) critically evaluate current experimental and predictive practices to propose Best Practice approaches that can be routinely used in research and regulatory frameworks. The project will host 3 post doc, 1 PhD and 4-5 Msc. students, assemble multiple national and international experts in combined toxicity assessment,and contribute to development of hazard/risk assessment through targeted communication, meetings, workshops, and peer-reviewed publications