Environmental risk assessment (ERA) has evolved significantly over the past decades, transitioning from a qualitative approach to a structured, science-based process that informs regulatory decisions. In the European Union (EU) and Switzerland, ERA is embedded in environmental regulations governing chemicals, particularly under frameworks such as REACH, the Water Framework Directive, and specific pesticide and biocide regulations. These frameworks aim to balance economic activity with environmental protection by assessing and mitigating risks to aquatic ecosystems. Despite regulatory advancements, several challenges remain in implementing timely and comprehensive risk assessments.

Following a brief introduction to this background, this presentation will summarise some aspects that the Risk Assessment Group at Ecotox Centre is currently involved with in national and international projects: One pressing issue is the delay in ERA of pesticides, where slow regulatory processes hinder effective environmental protection, and the difficulty in establishing robust feedback loops between evidenced environmental risks and approval conditions. Additionally, the assessment of persistent pollutants such as per- and polyfluoroalkyl substances (PFAS) and microplastics presents scientific and regulatory challenges due to their complex characteristics and data gaps regarding long-term ecological impacts. In this context, I will briefly touch on the importance of risk communication. Another critical aspect is the consideration of endocrine-disrupting chemicals (EDCs) in the derivation of environmental thresholds, where traditional risk assessment approaches struggle to capture the non-monotonic and low-dose effects of such substances.