Abstract
Urbanization has resulted in increased contaminant run-off in densely populated areas. Climate change is expected to result in a higher frequency of extreme weather events including torrential rainfall and storms. The contaminant levels of polycyclic aromatic hydrocarbons (PAH), chlorinated paraffins (CPF) and selected metals, in a small urban river were monitored during snow-melting and rainfall events to quantify the contribution to the contamination load of receiving waters of the inner Oslo fjord, Norway. Suspended particulate matter (SPM) was characterized with respect to levels of contaminants as well as toxic response using a battery of bioassays. The contaminant flux from the river to the fjord was quantified and assessed relative to sediment data. Historic data for near-shore sediment samples from the fjord were used to document urban input. The results show a clear episodic response in contaminant load emitted from the river to the fjord. The main historic input to the fjord was found to be PAH from pyrogenic sources like coal and wood burning as well as traffic. A significant reduction in the level of PAH was observed since the 1980s. The measured flux of CPF is consistent with on-going societal use despite a ban on the use of short chain CPF imposed in Norway from 2002.
Highlights
Expected climatic changes (CC) will lead to more extreme river discharges, extensive rainfall in the watershed and increased seawater levels (Hanssen-Bauer et al, 2017)
The objective of the present study was to investigate the transport of freely dissolved contaminants and contaminants associated with suspended particulate matter during events of MATERIALS AND METHODS
A complete overview over the monitoring data including, river flow, pH, electrical conductivity (EC), TOC and levels of nutrients is presented in Supplementary Figure S1
Summary
Expected climatic changes (CC) will lead to more extreme river discharges, extensive rainfall in the watershed and increased seawater levels (Hanssen-Bauer et al, 2017). Several nonatmospheric sources, such as tire wear, road dust and runoff from building facades, contribute to the contaminant load stored in the snow pack (Viklander, 1999). During a short snow melting period of a few weeks in spring (French and Binley, 2004), this contaminant load can be released to urban watersheds, which can result in peak concentrations. Meyer et al (2011) reported that transport of polycyclic aromatic hydrocarbons and pesticides increased considerably during snowmelt in an urban watershed near Toronto. The contaminant release was related to the intensity of the melting process as well as the properties of the organic chemicals (Meyer and Wania, 2011).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
