Förekomsten av sura sulfatjordar i Mälardalen: -en pilotstudie utförd åt SGU
Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
Acid sulphate soils is a wide spread problem along the northern coast of Sweden. This is causing great damage through low pH and leaching of metals out into the streams. These soils are estimated to be found in several places in Sweden but also in many other areas in the world. One of these areas in Sweden that are believed to contain these sediments is Mälardalen. The purpose of this study is to evaluate the extension of the acid sulphate soils in this area. This has been accomplished through measurements of pH in the field as well as laboratorial work such as measuring the organic substance in the soil. The soils sulphur content was also analysed in a number of the samples. A total of 29 places has been visited in the area. The examination has been done as a pilot survey for the SGU. The study wanted to confirm if the acid sulphate soils are a problem in Mälardalen and if there is a connection between the soils that has a high organic matter and by what time they were deposited, and that those attributes would be a link to a low pH. The results is indicating that there is some correlation, mainly when it comes to soils with high organic content that has been deposited around 1000 years ago. With these quality’s the probability is going to be higher to find a soil that has a low pH. When examining diagrams showing these relations, we get an R-square value for the trend lines from both cases showing a correlation of 30%. This give us the indication that there are also other factors which will affect the pH. In this study the pH has been used as an indicator to where acid sulphate soils could be located. One cannot say that a high pH will exclude the possibility for a soil to become an acid sulphate soil, in the cases where the oxidized zone is small or absent. To ensure this fact, the soil will need to be oxidized as well as analysed to establish the sulphur content in the sample.
This thesis has not shown any difference when it comes to the potential of acidification caused by these soils and the event of different kinds of sulphur compounds in Norrland and Mälardalen. According to our fulfilled literature studies the main difference are supposed to lay in the variation of the grain size in the different kinds of sediments. Air diffuse slower into a soil with a high content of clay compared to a soil with more silt. Clay may also have a bigger buffer system though high CaCo3 content or a high cation exchange capacity.
The samples from the sites of Brantshammar, Kungsängen and Hova got time to oxidize as well as going through a sulphur analysis. Though these examinations as well as evaluations in the field, these sites could be confirmed to be acid sulphate soils. The number of parameters that was analysed for the other sites in this study are said to be too few, and gave inadequate results, and not the amount of information needed to be able to confirm the soils as acid sulphate soils. However, the correlation and the probability did increase with the number of consistent variables. The area would need another survey when there have been findings of acid sulphate soils as well as potential acid sulphate soils in this area. Further investigations can supplement the results from this current study and give a more apparent picture of the area, due to the fact that only a smaller amount of places could be reached within the time range of this survey.
Place, publisher, year, edition, pages
2014. , 74 p.
, Självständigt arbete, 92
Sura sulfatjordar, Gyttjelera, pH, Svavelanalys, Organisk halt
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:uu:diva-227060OAI: oai:DiVA.org:uu-227060DiVA: diva2:729374
Sveriges Geologiska Undersökning
Bachelor Programme in Earth Science
2014-06-04, Hambergsalen, Innstitutionen för geovetenskaper, Villavägen 16, Uppsala, 09:20 (Swedish)
Sohlenius, Gustav, PhD
Hellqvist, Magnus, PhD