When remediation creates toxicological risk: transformation products and the soil exposome in contaminated...

Remediation is often considered successful when parent contaminants decline, visible pollution disappears, or extractable concentrations fall below target values. In contaminated agroecosystems, however, contaminant disappearance does not necessarily mean toxicological risk disappearance. Agricultural soils are reactive exposure interfaces where pollutants interact with minerals, organic matter, enzymes, microbes, and plant roots, often generating transformation products with different mobility, persistence, bioavailability, and toxicity from their parent compounds. This commentary proposes the soil exposome as a framework for evaluating remediated agroecosystems as dynamic exposure systems shaped by chemical mixtures, transformation pathways, microbial responses, plant uptake, and potential dietary exposure. We argue that remediation can create or obscure risk when assessment remains limited to removal efficiency or parent-compound monitoring. A toxicology-oriented evaluation should therefore integrate transformation-product profiling, effect-based bioassays, bioavailability testing, microbial and soil-function indicators, phytotoxicity assessment, and crop-safety verification. Moving from pollutant removal to verified exposure-system recovery is essential for ensuring that remediation reduces toxicological hazard while supporting soil function, crop safety, and long-term environmental sustainability.