Environmental risk assessment of accidental marine spills: A new approach combining an online dynamic Hazardous and Noxious substances database with numerical dispersion, risk and population modelling.

The foreseen rise on maritime transportation of Hazardous and Noxious Substances (HNS) increases the likelihood of accidents, leading to a higher risk of chemical spillage that can have severe ecological impacts. Considering the lack of information on HNS spills, the response to these events is less well established than those involving oil. Moreover, a paramount knowledge of the physicochemical and ecotoxicological properties of the substance involved is required for an effective environmental risk assessment and response to an HNS spill. In the present work, a new online interface, in which a dynamic HNS database feeds a chemical numerical dispersion model, was developed with the aim to improve predictions regarding the behaviour and environmental risk of HNS spills on marine ecosystems. Potential impacts to pelagic organisms were characterized by coupling model outputs with toxicity risk ratios. Furthermore, a simple population model was developed, foreseeing impacts at the ecological level. The integration of the developed tools establishes an innovative framework, which aims to improve predictions related to HNS plumes' behaviour and potential hazards to the marine environment and associated ecosystem services. Further, this new approach fosters an improved preparedness and response to coastal pollution incidents, enhancing effective decision making and management by competent authorities.