Golding Christopher J, Gobas Frank A P C, Birch Gavin E
School of Geosciences, University of Sydney, New South Wales 2006, Australia.
Environ Toxicol Chem. 2007 May;26(5):829-36. doi: 10.1897/06-378r.1.
It is well documented that the bioavailability of hydrophobic organic chemicals (HOCs) can vary substantially among sediments. This makes risk assessments based on total sediment concentrations problematic. The present study investigates the application of thin-film solid-phase extraction to measure bioavailable concentrations of phenanthrene in estuarine sediment by comparing concentrations of phenanthrene in the amphipod Corophium colo and in thin ethylene/vinyl acetate films at different concentrations in three geochemically different sediments. For all sediment types, concentrations of phenanthrene in sediments and thin films followed linear relationships, indicating first-order exchange kinetics. Organism/thin-film concentration ratios did not vary systematically among sediment types but dropped significantly with increasing phenanthrene concentration in the sediments. While at low phenanthrene concentrations in the sediment fugacities of phenanthrene in the amphipods approached the fugacities in the thin films, they were significantly lower than those in the sediments at higher concentrations. While phenanthrene concentrations in the three sediment types were identical, biota sediment accumulation factors and concentrations in amphipods and thin films were consistently lower in sediments enriched with black carbon than in sediments with sedimentary organic matter bearing a more diagenetic organic signature. It is concluded that, for the range of concentrations tested, thin-film solid-phase extraction can be a useful tool in the characterization of differences in bioavailability of HOCs among sediment types.
有充分文献记载，疏水性有机化合物（HOCs）在沉积物中的生物有效性在不同沉积物之间可能有很大差异。这使得基于沉积物总浓度的风险评估存在问题。本研究通过比较三种地球化学性质不同的沉积物中不同浓度下，双壳类动物Corophium colo和乙烯/醋酸乙烯酯薄膜中菲的浓度，研究了薄膜固相萃取法在测定河口沉积物中菲的生物可利用浓度方面的应用。对于所有沉积物类型，沉积物和薄膜中菲的浓度呈线性关系，表明存在一级交换动力学。生物/薄膜浓度比在不同沉积物类型之间没有系统变化，但随着沉积物中菲浓度的增加而显著下降。当沉积物中菲浓度较低时，双壳类动物中菲的逸度接近薄膜中的逸度，但在较高浓度时，它们显著低于沉积物中的逸度。虽然三种沉积物类型中的菲浓度相同，但与具有更多成岩有机特征的沉积有机质沉积物相比，富含黑碳的沉积物中生物沉积物积累因子以及双壳类动物和薄膜中的浓度始终较低。结论是，在所测试的浓度范围内，薄膜固相萃取法可成为表征不同沉积物类型中HOCs生物有效性差异的有用工具。
