Bioavailable Environmental Pollutant Patterns in Sediments from Passive Equilibrium Sampling

Abstract

Sediment-associated risks depend on the bioavailable fraction of organic chemicals and cannot be comprehended by their total concentrations. The present study investigated contamination patterns of bioavailable chemicals in sediments from various sites around the globe by using passive equilibrium sampling. The extracts had been characterized previously for mixture effects by in vitro reporter gene assays and were in this study analyzed using gas chromatography-high resolution mass spectrometry for 121 chemicals including both legacy and emerging contaminants. The spatial distribution of the detected chemicals revealed distinct contamination patterns among sampling sites. We identified compounds in common at the different sites but most contaminant mixtures were site-specific. The mixture effects of the detected chemicals were predicted with a mixture toxicity model from effect concentrations of bioactive single chemicals and detected concentrations, applying a joint model for concentration addition and independent action. The predicted mixture effects were dominated by polycyclic aromatic hydrocarbons, and among the chemicals with available effect data, 17% elicited oxidative stress response and 18% activated the arylhydrocarbon receptor. Except for two sites in Sweden, where 11 and 38% of the observed oxidative stress response were explained by the detected chemicals, less than 10% of effects in both biological end points were explained. These results provide a comprehensive investigation of bioavailable contamination patterns of sediments and may serve as an example of employing passive equilibrium sampling as a monitoring technique to integrate the risk of bioavailable sediment-associated chemicals in aquatic environments.

Bioanalytical Tools in Water Quality Assessment

“…They compared the bioassay results with chemical analysis and indicated that the detected chemicals could not entirely explain the effects detected with the bioassays. Two more recent studies evaluated Chinese sediments (Niu et al, 2020) and world-wide sampled sediments (Jahnke et al, 2018;Muz et al, 2020) using both total accelerated solvent extraction and PDMS and confirmed that typically less than 10% of the effects and BEQ were bioavailable (Table 15.1).…”

“…The same bioassays can be applied and a lot of the developments with respect of mapping chemicals to modes of action and toxicity pathways and mixture effects modelling can be directly translated to these other matrices. Iceberg modelling, for instance, has already been applied to sediments (Muz et al, 2020;Niu et al, 2020) and to biota samples (Jin et al, 2015a).…”

“…Despite of this massive analytical effort only a small fraction of effects (BEQ chem /BEQ bio and TU chem /TU bio ) could be explained by the detected chemicals: 0.1%-28% in whole sediment and 0.009%-3.3% in the bioavailable fraction of the Chinese sediments (Niu et al, 2020). Similarly, less than 10% effect in the bioavailable fraction of the sediments sampled worldwide could be explained by the detected chemicals with the exception of only one site in Sweden, where benzo[a]pyrene and benzo[k]fluoranthene together explained more than 30% of the effect in AREc32 (Muz et al, 2020).…”

Cumulative Risk Meets Inter-Individual Variability: Probabilistic Concentration Addition of Complex Mixture Exposures in a Population-Based Human In Vitro Model

“…There has been considerable recent interest and work on CA and other mixture modeling approaches, particularly in the context of in vitro assays and whole-mixture testing. For instance, several studies have found that effects of bioavailable extracts from contaminated sediments are consistent with CA or a model combining CA and independent action [ 15 , 16 , 17 ]. Additionally, both non-targeted and effect-directed approaches have been proposed to identify components within mixtures [ 18 , 19 ].…”

Understanding Source Terms of Anthropogenic Uranium in the Arctic Ocean – First 236u and 233u Dataset in Barents Sea Sediments

“…It is well known that sediments may act as a repository for a variety of contaminants including radionuclides (Durrant et al, 2018;Knies et al, 2006;Muz et al, 2020;Zaborska et al, 2011). Sediments with high content of clay minerals (e.g.…”