PM07 Pollutant Chemistry Transport, Cycling and Fate
Exhibit Hall
8:00 AM - Monday
(PM079) Speciation of polycyclic aromatic hydrocarbons in sediment interstitial water using solid phase microextraction.
Zhou, J L1, King, A J1, Readman, J W2, 1 University of Sussex, Brighton, East Sussex, UK2 Plymouth Marine Laboratory, Plymouth, Devon, UK
ABSTRACT- Sediment porewater is an important sink for persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs). The solid-phase microextraction (SPME) technique based on the sorption of target analytes on the fibre of SPME has advantages over traditional extraction techniques. A robust SPME-GC/MS method has been developed to enable reliable and quantitative measurements of PAH concentrations in porewater. The influence of various key parameters on PAH extraction efficiency by SPME was thoroughly evaluated. Results show that the sufficient fibre exposure time and the use of agitation during exposure are essential in enhancing SPME performance; this is particularly true for low molecular mass PAHs. The presence of colloidal matter in porewater samples was shown to significantly reduce the extraction efficiency, suggesting that SPME primarily measures the truly dissolved compounds. The extraction efficiency was also affected by the sample volume, emphasising the need to maintain the same volume of sample and calibration standards for quantitative analysis. The method developed was then applied to extract PAHs from porewater samples from sediment cores collected from the Mersey Estuary and Brighton Marina, UK. In addition, the same set of samples were extracted by liquid/liquid extraction to determine the total PAH concentration (dissolved plus colloid-bound). The partition coefficients of PAHs between colloidal and dissolved phases were determined for unravelling the mechanism of such interactions.
Key words: PAHs, SPME, Colloids, Pore water