Toward Refined Environmental Scenarios for Ecological RiskrnAssessment of Down-the-Drain Chemicals in FreshwaterrnEnvironments

摘要

Current regulatory practice for chemical risk assessment suffers from the lack of realism in conventional frameworks. Despiternsignificant advances in exposure and ecological effect modeling, the implementation of novel approaches as high-tier optionsrnfor prospective regulatory risk assessment remains limited, particularly among general chemicals such as down-the-drainrningredients. While reviewing the current state of the art in environmental exposure and ecological effect modeling, we proposerna scenario-based framework that enables a better integration of exposure and effect assessments in a tiered approach. Globaltorncatchment-scale spatially explicit exposure models can be used to identify areas of higher exposure and to generaternecologically relevant exposure information for input into effect models. Numerous examples of mechanistic ecological effectrnmodels demonstrate that it is technically feasible to extrapolate from individual-level effects to effects at higher levels ofrnbiological organization and from laboratory to environmental conditions. However, the data required to parameterize effectrnmodels that can embrace the complexity of ecosystems are large and require a targeted approach. Experimental effortsrnshould, therefore, focus on vulnerable species and/or traits and ecological conditions of relevance. We outline key researchrnneeds to address the challenges that currently hinder the practical application of advanced model-based approaches to riskrnassessment of down-the-drain chemicals.