Microplastics Are Chemically Active, and Could Cause Biological Harm

Nature & Climate Perspective

**Emerging evidence of microplastic chemical reactivity introduces acute ecotoxicity risks that undermine aquatic biodiversity and the long-term sequestration integrity of marine and coastal carbon sinks. **

• Chemically reactive surfaces on microplastics induce cellular oxidative stress and toxicity in marine primary producers, disrupting trophic chains and benthic biodiversity.
• The biological degradation of marine biotas impairs the ocean's biological carbon pump, destabilizing sediment carbon capture within vital Blue Carbon ecosystems.
• Toxic plastic interfaces compromise benthic layer biochemistry, challenging ecological baseline stability and permanence assumptions under coastal LULUCF accounting frameworks.

Market & Policy Outlook

**Heightened toxicity profiles will accelerate corporate supply-chain accountability under SBTi frameworks and force stricter do-no-harm safeguards under the ICVCM Core Carbon Principles. **

• Regulatory frameworks governing pollutant baselines will tighten, prompting the Article 6.4 Supervisory Body to integrate stringent chemical toxicity risk assessments into project verification mechanisms.
• Contrasting with the ICVCM Core Carbon Principles (CCPs), nature-based project developers lacking comprehensive contamination screening risk losing eligibility under CCP Safeguard standards, driving market bifurcations in project valuation.
• Corporate emitters face intensified Scope 3 scrutiny from stakeholder rating bodies, demanding circular-economy shifts to preserve sustainability credentials under SBTi and B Corp compliance standards.