Making waves: The ecological risk illusion-chemical tools are not final arbiters

Accurate ecological risk assessment underpins environmental policy, yet current practice often over-relies on chemical exposure proxies. Passive sampling technologies, such as diffusive gradients in thin films (DGT), have transformed monitoring by estimating chemically labile fractions rather than total concentrations. However, an illusion persists: that DGT-measured "labile" concentrations can directly predict ecological outcomes. This assumption overlooks trophic transfer, physiological selectivity, and contaminant transformation processes that ultimately shape organismal and ecosystem responses. Here, we argue that DGT should be repositioned as an early-warning sentinel of pollutant accessibility, not a final arbiter of ecological risk. We highlight the conceptual mismatch between diffusion-based chemical proxies and active biological uptake and explain why this gap constrains predictive power, particularly for higher trophic organisms. Finally, we outline a next-generation framework integrating biomimetic samplers, mechanistic bioaccumulation models, and multi-trophic validation. By aligning chemical precision with biological reality, ecological risk assessment can evolve from static exposure indicators toward predictive, policy-relevant tools.