Analysis of pyrethroids in sediment pore water by solid-phase microextraction

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Ecotoxicology

Background:

• Pyrethroid insecticides pose an emerging water quality concern due to sediment toxicity.
• Their toxicity is linked to freely dissolved concentrations in pore water, driven by hydrophobicity.

Purpose of the Study:

• Evaluate Solid-Phase Microextraction (SPME) for analyzing free pyrethroid concentrations in sediment pore water.
• Compare SPME measurements with conventional Liquid-Liquid Extraction (LLE) for total pore-water concentrations.

Main Methods:

• Solid-phase microextraction (SPME) was used to determine free pyrethroid concentrations.
• SPME measurements were compared against total concentrations obtained via liquid-liquid extraction (LLE).
• The SPME method's detection limits and reproducibility were assessed.

Main Results:

• Free pyrethroid concentrations (C(w-SPME)) ranged from 4.1–37% (freshwater) and 3.2–13.3% (marine) of total concentrations (C(w-LLE)).
• Pyrethroids predominantly partitioned into dissolved organic matter in pore water.
• SPME method detection limits were below lethal concentrations for aquatic organisms, with high reproducibility.

Conclusions:

• SPME is a sensitive, reproducible, and practical method for screening pyrethroid contamination in sediments.
• The phase distribution of pyrethroids is influenced by sediment type and environmental conditions.
• SPME aids in assessing sediment toxicity risks from pyrethroid contamination.