Towards regulatory measures for microplastics in soils: further challenges and QA/QC guidelines for harmonized workflows

Plastic pollution is increasingly recognized as a threat to terrestrial environments, particularly soil. As plastics enter agricultural, roadside, urban, natural, and forest soil with potential adverse effects, understanding and managing their occurrence is a top environmental priority. The absence of harmonized methodologies challenges the comprehensive quantification of plastics, hinders data comparability and therefore identification of plastic entry routes and pollution hotspots in the soil environment. Methodological discrepancies hinder the generation of comparable data and risk assessments, ultimately limiting the effectiveness of regulatory and remedial measures. This article aims to support accurate assessment and informed soil protection strategies by critically examining existing legal regulations, highlighting regional best-practice examples. It sets out the complexity and obstacles, as well as possible solutions, in individual areas to combat the plastic problem. Further, special attention is given to quality assurance and quality control (QA/QC), as the risk of inaccurate conclusions is high, and the consequences are significant, ranging from misguided policy to flawed risk assessments. A QA/QC-focused framework is provided to improve the reliability and comparability of plastic analysis in soil. Emphasizing these challenges will help push the field toward method harmonization, credibility, and scientific maturity, ensuring that research findings are actionable and trustworthy.