Use of passive samplers for improving oil toxicity and spill effects assessment

- Methods to quantify dissolved hydrocarbons needed to link oil exposures to toxicity.
- Solid phase microextraction (SPME) fibers used to measure dissolved hydrocarbons.
- SPME results reliably predicted acute toxicity for range of dispersed oils.
- Oil droplets and chemical dispersant did not significantly contribute to toxicity.
- SPME analysis improves oil exposure assessment in lab and field studies.

Methods that quantify dissolved hydrocarbons are needed to link oil exposures to toxicity. Solid phase microextraction (SPME) fibers can serve this purpose. If fibers are equilibrated with oiled water, dissolved hydrocarbons partition to and are concentrated on the fiber. The absorbed concentration (Cpolymer) can be quantified by thermal desorption using GC/FID. Further, given that the site of toxic action is hypothesized as biota lipid and partitioning of hydrocarbons to lipid and fibers is well correlated, Cpolymer is hypothesized to be a surrogate for toxicity prediction. To test this method, toxicity data for physically and chemically dispersed oils were generated for shrimp, Americamysis bahia, and compared to test exposures characterized by Cpolymer. Results indicated that Cpolymer reliably predicted toxicity across oils and dispersions. To illustrate field application, SPME results are reported for oil spills at the Ohmsett facility. SPME fibers provide a practical tool to improve characterization of oil exposures and predict effects in future lab and field studies.