Source origin of Polycyclic Aromatic Hydrocarbons (PAHs) in sediment, and fate of organic contaminants in dragonfly larvae (Aeshnidae) from highway sedimentation ponds and natural ponds
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- Avhandlinger 
Road and tunnel wash runoff contain a mixture of organic and inorganic contaminants that threatens the quality of natural water bodies, and the health of the organisms dependent on these waters. A variety of treatment solutions can be established to reduce potential runoff impact. The most common mitigation adopted in Norway is the installation of nature-based sedimentation ponds. A variety of organisms migrate to these ponds over time, and are thus at risk of exposure to high levels of traffic-related contaminants. Dragonflies, with their aquatic life stage, can potentially transfer these substances back to the terrestrial environment. This aim of this study was to assess the source origin and fate of polycyclic aromatic hydrocarbons (PAHs), and two types of organobromine compounds used as flame retardants, polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) in three natural and seven highway sedimentation ponds in Norway. Sediment samples were used to determine source origin of PAHs. The concentrations of organic contaminants were analyzed in dragonfly larvae to investigate their potential role as pollutant vectors across ecosystems. Parent and alkylated PAHs in sediment were measured, and the results were used to characterize the source of PAHs. Distribution patterns of selected PAHs showed similar patterns in all sedimentation ponds, and distinct patterns in natural ponds. Specific PAH ratios indicated that sedimentation ponds are dominated by petrogenic PAHs, whereas natural ponds showed pyrogenic dominance. Moreover, the addition of alkylated PAHs resulted in significant changes in the environmental quality standard values related to sediment pollution. PAHs, PBDEs and HBCD were quantified in sediment, and larval exuvia and tissue. Haemolymph was also analyzed for PAH metabolites. The results indicated that dragonfly larvae accumulate PAHs in the exuvia, but not sufficiently enough to avoid bioaccumulation. 1-hydroxypyrene was detected only in some of the samples and at very low concentrations, and thus it is not clear whether larvae are able to metabolize PAHs at low levels or if the metabolite has come from others sources. Nevertheless, the results suggest that metabolites are not suitable biomarkers for PAH exposure in dragonfly larvae. Levels of BFRs were detected at very low concentrations, and the results were qualified. Overall, there was no indication of bioaccumulation of BFRs.
Master thesis in toxicology. University of Oslo. Department of Biosciences. Faculty of Mathematics and Natural Sciences.