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A Whole Cell Bioreporter Approach to Assess Transport and Bioavailability of Organic Contaminants in Water Unsaturated Systems
Published on: December 24, 2014
PAH bioavailability in field sediments: comparing different methods for predicting in situ bioaccumulation.
Stephan A Van der Heijden1, Michiel T O Jonker
1Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80177, 3508 TD Utrecht, The Netherlands. s.a.vanderheijden@uu.nl
Environmental Science & Technology
|June 24, 2009
Summary
Site-specific bioavailability assessments for polycyclic aromatic hydrocarbons (PAHs) are crucial. In situ solid-phase microextraction (SPME) and laboratory-based polyoxymethylene solid-phase extraction (POM-SPE) show promise for predicting chemical exposure in aquatic worms.
Area of Science:
- Environmental Chemistry
- Ecotoxicology
- Analytical Chemistry
Background:
- Bioavailability of sediment-bound chemicals is key to assessing ecological risk.
- Existing laboratory methods for measuring bioavailability often fail to predict in situ conditions.
- Site-specific factors significantly influence chemical exposure and risk in aquatic ecosystems.
Purpose of the Study:
- To evaluate the effectiveness of various analytical methods in predicting in situ bioavailability of polycyclic aromatic hydrocarbons (PAHs).
- To compare the predictive power of in situ and laboratory-based extraction techniques.
- To advocate for site-specific risk assessment approaches over generic methods.
Main Methods:
- In situ exposure of solid-phase microextraction (SPME) fibers and aquatic worms (Lumbriculus variegatus) at three field locations.
- Laboratory analysis of sediments using SPME, polyoxymethylene solid-phase extraction (POM-SPE), hydroxypropyl-beta-cyclodextrin (HPCD), and 6h-Tenax extraction.
- Calculation of biotic PAH levels using equilibrium partitioning and comparison with measured concentrations in field-exposed worms.
Main Results:
- In situ SPME and laboratory-based POM-SPE provided the most accurate predictions of PAH concentrations in aquatic worms, within a factor of 10.
- Generic risk assessment approaches overpredicted biotic PAH concentrations by 10-100 fold.
- In situ SPME-derived distribution coefficients and biota-to-sediment accumulation factors differed significantly from generic values.
Conclusions:
- In situ SPME and laboratory-based POM-SPE are promising tools for site-specific risk assessment of PAHs in sediments.
- Current generic risk assessment methods overestimate exposure and risk, highlighting the need for site-specific evaluations.
- Accurate prediction of in situ bioavailability requires methods that account for site-specific sediment characteristics.
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