Twin Threats in the Deepest Ocean: Novel PFAS Drive Exposure While Legacy PFAS Drive Risk
Jingqian Xie1, Mei Liu2, Gaoxin Zhang2
1College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai 201306, China.
Environmental Science & Technology
|April 7, 2026
Summary
Per- and polyfluoroalkyl substances (PFAS) were found in hadal amphipods, not seawater or sediment. Long-chain PFAS pose a higher risk than short-chain ones, showing structural changes don't eliminate hazards.
Area of Science:
- Environmental Chemistry
- Ecotoxicology
- Marine Biology
Background:
- Per- and polyfluoroalkyl substances (PFAS) are globally distributed contaminants.
- The hadal zone's PFAS contamination and novel compound presence are largely unknown.
- Understanding PFAS in deep-sea organisms is crucial for ecological risk assessment.
Purpose of the Study:
- To investigate PFAS occurrence and characteristics in hadal amphipods from three ocean trenches.
- To analyze PFAS bioaccumulation patterns and assess associated risks.
- To evaluate the impact of structural modifications on PFAS hazards in the hadal environment.
Main Methods:
- Detection and quantification of 15 PFAS in amphipods, seawater, and sediment samples.
- Organism-water partitioning, structural analysis (COSMO-RS), and bioaccumulation prediction (neural networks).
- Prioritization of PFAS risks using a persistence-bioaccumulation-toxicity (PBT) framework.
Main Results:
- PFAS detected in amphipods from Mariana, Mussau, and New Britain Trenches (0.4-37.5 ng g-1 dw); seawater and sediment below detection limits.
- Short-chain PFAS (PFBA, PFPeA) were abundant but posed minimal risk; long-chain PFAS (PFTrDA, PFUnDA) were less abundant but higher risk.
- Novel compound F-53B detected exclusively in Mariana amphipods; accumulation patterns influenced by exposure and partitioning.
Conclusions:
- Hadal amphipods accumulate diverse PFAS, with varying risk potentials based on chain length.
- Structural modifications in PFAS do not guarantee reduced environmental hazards.
- Hadal organisms must be included in global chemical risk evaluations to ensure comprehensive assessment.
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