Bioavailability of polycyclic aromatic hydrocarbons in field‐contaminated Anacostia River (Washington, DC) sediment

Abstract

Sediment-water partitioning behavior and bioavailability of five polycyclic aromatic hydrocarbons (PAHs; phenanthrene, pyrene, chrysene, benzo[k]fluoranthene, and benzo[a]pyrene) were measured in field-contaminated sediment collected from moderately polluted regions of the Anacostia River (Washington, DC, U.S.A.). Much of the sediment PAH burden was resistant to desorption: Effective partition coefficients were 2- to 10-fold greater than expected from literature values, and more than 80% of PAHs remained sorbed after treatment of the sediment with a nonionic polymeric adsorbent (Amberlite XAD-2) for 20 h. Bioaccumulation, elimination, and assimilation of each PAH in the deposit-feeding tubificid oligochaete Ilyodrilus templetoni were measured and compared with the equivalent measurements from laboratory-inoculated sediment. Ilyodrilus templetoni effectively accessed the desorption-resistant fraction of these organic contaminants, as exhibited by high single-gut passage assimilation efficiencies (ASEs) of the five PAHs (60% < ASE < 90%). However, steady-state accumulations of PAHs by I. templetoni were very low and consistent with low pore-water concentrations. The present results suggest that steady-state accumulation of PAHs is controlled by pore-water concentrations and is not necessarily related to route of uptake or assimilation efficiencies.

Demonstration and Evaluation of Solid Phase Microextraction for the Assessment of Bioavailability and Contaminant Mobility

“…The goal is demonstration of a tool that can provide an assessment of the bioavailable contaminants at a particular site and thus provide a tool that can help set cleanup levels that are neither overly conservative nor lead to unacceptable exposure and risks at a site. 4 …”

“…One advantage of the sorbent exposure for two different times or two different size fibers is that there is no additional analytical complexity. In addition, if the compounds of interest represent a wide range of hydrophobicities such as PAH 16 , PAH 34 or PCB congeners, data from all compounds over the entire range of hydrophobicities can be used to calibrate the model and yield higher accuracy estimates of the required non-equilibrium corrections. The approach can be applied to any passive sampling device using PDMS, POM, PE or e.g.…”

“…bulk sediment concentration) is unreliable and often provides poor predictions 31 . Sediment porewater concentration of HOCs, particularly the freely dissolved porewater concentration, however, has been shown to be a good indicator of bioavailability 32,33,34,35 . Predicted porewater concentration was also used to develop equilibrium partitioning benchmarks for protecting benthic organisms in PAH contaminated sediments by the U.S. EPA 36 although this approach is limited by the ability to estimate porewater concentrations in sediments.…”

“…Our previous studies2 , 4 have shown that measurement of porewater concentrations via conventional approaches can be used to predict bioaccumulation and bioavailability of sedimentassociated PAHs. In this study, this hypothesis will be further tested with a broader range of chemicals and sediments, and use of matrix-SPME to measure the porewater concentration.…”

Polyethylene passive samplers to determine sediment–pore water distribution coefficients of persistent organic pollutants in five heavily contaminated dredged sediments

“…The behaviour of real decades-weathered sediment could be notably different in terms of native contaminant desorption (Chai et al, 2006). In fact, the presence of separate phases would be a function of the oil content but also of the type and the amount of organic carbon (Jonker and Barendregt, 2006) and the presence of clay-humic complexes (Lu et al, 2006). This reveals the need for a better assessment of the CSPC value used to define the applicability limits of the model.…”