A passive sampler based on solid phase microextraction (SPME) for sediment-associated organic pollutants: Comparing...

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Analytical Chemistry

Background:

• Estuarine sediments accumulate hydrophobic organic chemicals (HOCs), including polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCBs), and organochlorine pesticides.
• Challenges persist in regulating sediment quality due to discrepancies between predictive models and measured bioaccumulation and toxicity.
• Accurate assessment of HOC bioavailability is crucial for protecting aquatic ecosystem health.

Purpose of the Study:

• To evaluate the efficacy of solid phase microextraction (SPME) passive samplers in measuring freely dissolved HOC concentrations (Cfree).
• To determine if SPME-derived Cfree can serve as a reliable proxy for bioaccumulation (Cb) in estuarine organisms.
• To reduce uncertainty in sediment quality regulations by improving bioavailability assessments.

Main Methods:

• Laboratory and field studies were conducted using SPME passive samplers to measure Cfree of target HOCs.
• SPME samplers were deployed alongside bivalves (Macoma spp.) and invertebrates (Nereis spp.) in spiked and naturally contaminated sediments.
• In situ deployment of SPME samplers in an estuarine field site for up to one month.

Main Results:

• SPME-derived Cfree for organochlorines showed a strong correlation with organism tissue concentrations (Cb) in laboratory experiments.
• This positive association between Cfree and Cb was also observed in field deployments with endemic bivalves.
• Concordance for PAHs was more variable, potentially due to invertebrate biotransformation.

Conclusions:

• SPME passive samplers are suitable proxies for assessing organochlorine bioaccumulation from sediments in both laboratory and field settings.
• This method enhances the accuracy of bioavailability estimations, reducing uncertainty in sediment quality assessments.
• SPME offers a valuable tool for developing more effective, science-based sediment quality regulations for impaired waterbodies.