Priority Pollutants Effects on Aquatic Ecosystems Evaluated through Ecotoxicity, Impact, and Risk Assessments

As water management is still a problem of international concern, scientists and practitioners are collaborating to develop new tools and methods to improve and help in the decision-making process. When addressing the priority pollutant monitoring and impact assessment, the ecotoxicity effects, carcinogenic and non-carcinogenic, should be considered together with the exposure factor and health hazards. The main goals of this study were to assess the ecological and health hazards and to apply integrated impact and risk assessment based on the ecotoxicity and exposure factors of each priority pollutant present in the aquatic ecosystem. This study used as a database the measured concentrations of 5 inorganic and 14 organic priority pollutants from the Siret river basin from NE Romania, from 18 river sections monitored in the period 2015–2020. The USEtox methodology and a new integrated index for environmental impact and risk assessment were developed and applied to evaluate the ecological and health hazards and environmental impacts and risks within the river basin. The total impact scores for heavy metals ranged from 2 × 10³ to 2.25 × 10⁹, and those for organic pollutants ranged from 2.72 × 10⁻¹ to 2.95 × 10⁶. The environmental risk in the case of inorganic priority pollutants ranged between 5.56 and 3136.35, and that in the case of organic pollutants was between 4.69 and 4059.17. The results revealed that there is a major to catastrophic environmental impact in almost all monitored river sections (10 out of 18), and the overall risk exposure was found to be at a significant to a major level. This study proved the harmful effects that the priority pollutants may have, even in very small concentrations, on non-target organisms and suggests that greater control over the pollution sources and mitigation of environmental impacts and risks should be applied.