Application of surrogate methods for assessing the bioavailability of PAHs in sediments to a sediment ingesting bivalve

Abstract

The usefulness of two surrogate methods for rapidly determining the bioavailability of PAHs in hydrocarbon-contaminated marine sediments was assessed. Comparisons are made between the PAHs accumulated by the benthic bivalve, Tellina deltoidalis, and the extractable-PAHs determined using a 6-h XAD-2 resin desorption method and a 4-h gut fluid mimic (GFM) extraction method. There were significant positive relationships between PAH bioaccumulation by the bivalves and sediment PAH concentrations. These relationships were not improved by normalising the sediment PAH concentrations to the organic carbon concentration. The average percentage lipid content of the bivalves was 1.47+/-0.22% and BSAFs for total-PAHs ranged from 0.06 to 0.80 (kgOC/kg lipid). The XAD-2 and GFM methods both extracted varying amounts of PAHs from the sediments. Low concentrations of PAHs were extracted by the GFM method (0.2-3.6% of total-PAHs in sediments) and the GFM results were inadequate for generalising about the bioavailability of the PAHs in the sediments. The XAD-2 method extracted greater amounts of PAHs (3-34% of total-PAHs in sediments), however, the total-PAH concentrations in the sediments provided a better, or equally good, prediction of PAH bioaccumulation by T. deltoidalis. The results indicated that these methods required further development before they can be applied routinely as surrogate methods for assessing the bioavailability of PAHs in sediments. Future research should be directed towards lowering detection limits and obtaining comparative data for a greater range of sediment types, contaminant classes and concentrations, and organisms of different feeding guilds and with different gut chemistry.

Polycyclic Aromatic Hydrocarbons in Seawater, Sediment, and Rock Oyster Saccostrea cucullata from the Northern Part of the Persian Gulf (Bushehr Province)

“…The extracted lipids were weighed after desiccation to determine percentage lipid content. Percent moisture content of bivalve tissues was determined by gravimetry after drying the soft tissue of the bivalves in the oven (110°C) overnight (Simpson et al 2006).…”

Chemical techniques for assessing bioavailability of sediment-associated contaminants: SPME versus Tenax extraction

“…Ideally, differing sorbents other than Tenax might be used for compounds with different polarity, but the authors are unaware of any research completed in this area except of the use of XAD-2 absorbents. 62,63 Conversely there are more choices of the SPME fibers and suites of coatings in polarity have been commercialized 30 and theoretically more selective and specific SPME coatings could be developed. Additionally, SPME fibers can be exposed simultaneously with the organisms in the laboratory or may be used in situ which may better mimic organism exposure in the field.…”

Impact of hydrocarbons from a diesel fuel on the germination and early growth of subantarctic plants

“…Arguably two of the most important factors in determining the toxicity of petroleum hydrocarbons in soil are the level of organic matter in the soil and the duration or age of contamination. The ameliorating effect of OC on hydrocarbon bioavailability is well established, with hydrocarbon content generally normalised to the OC concentration in sediment toxicity assessments [28].…”