Modernizing the TRIAD ecological risk assessment framework. Part I: Analytical integration for an updated TRIAD framework

The TRIAD approach is a widely-used tool for site-specific ecological risk assessment (ERA), integrating three Lines of Evidence (LoE): chemical, ecotoxicological, and ecological. Calculating Integrated Risk (IR) requires determining the Weight of Evidence (WoE) for each LoE, a process heavily dependent on Expert Judgment (EJ). Originally developed to address limitations of generic chemical benchmarks that overlooked in situ contaminant interactions and bioavailability, TRIAD assessments now face criticism for relying on EJ protocols that lack transparency, leading to conflicting results that limit the framework’s utility and prevent cross-study data aggregation. The rising complexity of environmental contamination further demands new testing and analysis technologies, without which TRIAD cannot remain an ecologically relevant or viable tool. We propose a modernized TRIAD approach that: (1) employs Structured EJ protocols at every stage, to minimize and quantify expert uncertainty, (2) utilizes minimum datasets (MDS) of soil quality indicators (SQIs) to improve standardization and cost-efficiency, (3) integrates structured Multi-Criteria Decision Analysis (MCDA) protocols and multivariate analyses for criteria and test selection, weighting, and IR calculation – preserving complex environmental relationships, (4) develops machine learning (ML) models for processing large environmental datasets, rigorous integration of data among TRIAD LoEs, and predictive risk assessment across diverse field conditions, and (5) incorporates molecular ‘omic’ methods – sequencing, proteomics, and metabolomics – providing high-resolution biological indicators that address the critical lack of sensitive biological parameters in ERA. The first four proposals are developed here; proposal (5) is addressed separately in “Part II: Omic methods for high-resolution biological risk indicators” (Djomehri et al., 2026). These modernizations have the potential to elevate TRIAD into a comprehensive, versatile framework for contaminated site assessment and management, offering a robust foundation for EU soil health directives and remediation strategies.