Ecological risk assessment for the river basin of Göta Älv - A study according to the PETAR procedure

Examensarbete för masterexamen

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Type: Examensarbete för masterexamen
Master Thesis
Title: Ecological risk assessment for the river basin of Göta Älv - A study according to the PETAR procedure
Authors: Westerdahl, Jenny
Abstract: The ecological risks to the receptor organisms salmon and trout in the Göta älv river basin posed by five groups of pollutants; pharmaceuticals, nutrients, pesticides, metals and organic pollutants, have been studied in this thesis. The ecological risks were characterised with regard to both subareas within the river basin as well as with regard to the different pollutants. This study was performed according to the PETAR procedure, a procedure of ecological risk assessment, and the data used was obtained from both literature and model calculations. Two subareas were identified as being of higher risk than the others; one area around Trollhättan and one located at Älvängen. In both of these areas, there is a relatively large wastewater treatment plant located that emits large amounts of several pollutants. Regarding the risk characterisation of the different pollutants, pharmaceuticals were identified as being of the highest risk to the aquatic ecosystem. For the pharmaceuticals, both literature and model calculations indicate that the environmental concentrations in water are higher than the corresponding PNEC values. For the pharmaceutical propranolol, the model calculations showed that the environmental concentrations were six times higher than the PNEC value. T herefore, the pharmaceuticals in Göta älv may cause adverse effects to the aquatic ecosystem. The results for the pesticides and organic pollutants are inconclusive; there are large differences in expected concentrations between the literature and the model calculations. One explanation for this may be differences in dilution between the sites studied in the literature and the conditions in Göta älv. Concentrations of metals and nutrients are low, close to background concentrations, and are therefore believed not to pose a risk to salmon and trout. Due to the lack of data, both of site specific and general data for some of the pollutants, there are uncertainties within these results. The results from this study should therefore be seen as indicative and they can be used to prioritise the need for further studies. To confirm these results, site-specific measurements and/or more detailed model calculations are necessary. There is a need to perform more detailed risk assessments for pharmaceuticals, pesticides and organic pollutants since the knowledge about these pollutants is incomplete and regional studies like this one indicate that they may be problematic in the environment. Further studies can increase the understanding of the risks that they pose and how this risk is best managed.
Keywords: Miljöteknik;Environmental engineering
Issue Date: 2009
Publisher: Chalmers tekniska högskola / Institutionen för energi och miljö
Chalmers University of Technology / Department of Energy and Environment
Series/Report no.: Report - Division of Environmental Systems Analysis, Chalmers University of Technology : 2009:8
Collection:Examensarbeten för masterexamen // Master Theses

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