Environmental risk assessment (ERA) is often considered as the most transparent, objective and reliable
decision-making tool for informing the risk management of chemicals and nanomaterials. ERAs are based on
the assumption that it is possible to provide accurate estimates of hazard and exposure and, subsequently, to
quantify risk. In this paper we argue that since the quantification of risk is dominated by uncertainties, ERAs
do not provide a transparent or an objective foundation for decision-making and they should therefore not be
considered as a “holy grail” for informing risk management