Impact of urbanization on the concentrations and distribution of organic contaminants in boreal lake sediments

Abstract

The main goal of this study was to evaluate the impacts of a middle-sized Finnish urban area on the quality of sediments in an adjacent boreal lake. We investigated the sources and distribution of organic pollutants (polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs)) in the sediments from urban stormwater traps and from Lake Vesijärvi. Grab surface sediment samples were taken from Lake Vesijärvi at various distances (25-2,000 m) from four major stormwater drainage outlets and at 15 urban stormwater traps in areas with different degrees of urbanization. These samples were analysed for 16 PAHs and 28 PCBs with gas chromatography-mass spectrometry. The concentrations of pollutants in the lake sediments were elevated in the vicinity of the urban shore (∑PAH 3-16, ∑PCB up to 0.02-0.3 mg/kg dw) and decreased as a function of distance (∑PAH 0.1-2.5, ∑PCB 0.01-0.3 mg/kg dw at a distance of more than 500 m from the shore), whereas contamination levels in suburban areas were notably lower (∑PAH 0.1-3, ∑PCB < LOQ-0.03 mg/kg dw; did not decline with distance). Possible sources and pathways of contamination were also investigated. The majority of stormwater trap sediments contained predominantly asphalt-derived PAHs due to pulverized pavement. PAHs in lake sediments were of pyrogenic origin, including the combustion of gasoline, diesel and coal. Suggested pathways of lake contamination are urban runoff discharge, boat traffic and atmospheric deposition.

The abundance of health-associated bacteria is altered in PAH polluted soils—Implications for health in urban areas?

“…PAH concentrations were determined using toluene extraction as described in Nordic Guidelines for Chemical Analysis of Contaminated Soil Samples [ 40 ] and analyzed as described earlier [ 41 ] with the exception that aqueous sodium pyrophosphate decahydrate solution (0.05 M) instead of hexane was used. The extracts were analyzed with Shimadzu GC–MS-QP5000 system equipped with AOC-20i autoinjector and 30-m ZB-5MS column (0.25 mm i.d., 0.25 μm film thickness).…”

Urban snow indicates pollution originating from road traffic

“…First, during snowmelt these pollutants get washed into roadside inlets to stormwater sewers and further to adjacent water bodies, where soluble nutrient pollutants in particular are readily available for biological uptake. Part of the particle-bound pollutants can get trapped to the sewage system and partly end up in the sediment of water bodies (Honkonen and Rantalainen, 2013). Also sedimenting, particle-bound material can become available for decomposition and biological uptake in the water column via resuspension, a characteristic feature of shallow areas in lakes.…”

Half-lives of PAHs and temporal microbiota changes in commonly used urban landscaping materials

“…PAH concentrations were determined using hexane and acetone mixture (1:1 v/v) extraction and analyzed as described by Honkonen & Rantalainen (2013) using gas chromatography-mass spectrometry (Shimadzu GC–MS-QP5000) system equipped with an AOC-20i autoinjector and a 30-m ZB-5MS column (0.25 mm i.d., 0.25 µm film thickness). The mass spectrometer interface temperature was set to 280 °C.…”