This study aims to assess the potential environmental risks posed by sediments in five lakes affected by present or historical metallurgy. Special attention is paid to the lakes Dammsjön and Värlingen in mid Sweden, where the sediments were contaminated after a breach in a nearby tailings dam used for storing residue from a metal processing plant. The sediments were examined for their metal content by X-ray fluorescence spectroscopy (XRF) analysis of loose powder samples. A subset of the samples from Dammsjön and Värlingen was also used for a simple pH-analysis and an experimental XRF analysis of evaporated leachate. To obtain a larger variety of samples for the XRF analysis of evaporated leachate, loose powder sediment and leachate from three additional lakes affected by extractive metallurgy, Tisken, Gruvsjön and Storjuktan, were likewise examined with XRF. The sediments from all lakes contained high levels of metals, and environmental standards for Pb (in all lakes) and Cd (in Storjuktan) were exceeded. The leachate tests showed that metals can be extracted using this method, including Cu and Ni in lake Tisken. This might indicatehigher bioavailability, but further studies are needed to confirm this interpretation. Dammsjön andVärlingen are contaminated by several metals, including Hg and As. The pH-analysis indicated that the deposited sediment is not the source of the prolonged low pH in Dammsjön, and that another source, possibly continued leaks from the tailings dam, needs to be found. The results call for close environmental monitoring, to minimise further contamination and damage to the environment.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:umu-133405 |
| Date | January 2017 |
| Creators | Raninen, Linn |
| Publisher | Umeå universitet, Institutionen för ekologi, miljö och geovetenskap |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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