The Kvarntorp area, some 200 km SW of Stockholm, Sweden, is a former mining site for alum shale. Kvarntorpshögen is a refuse dump from the hydrocarbon extraction during 1940-1965. The area is also dotted by abandoned quarries, which most are water filled today. The area is divided into two watersheds; the central and the eastern. Frommestabäcken is the main watercourse flowing out of the central watershed while Frogestabäcken is the corresponding watercourse in the eastern watershed. These two watercourses have been sampled annually since 1994 by consulting companies for the municipality of Kumla. The sampling sites at Ulftorpsbäcken (main inlet to the central watershed) and at the outlet from Serpentindammssystemet (the water treatment system in the central watershed) was added to the sampling program in 1997 and 1996 respectively. Other consulting companies have sampled the groundwater around Kvarntorpshögen (in 2004) and the water in the lake Norrtorpssjön (in 2004), which is an old water filled quarry. The lake Norrtorpssjön has also been sampled as part of a project performed by Örebro University. This thesis is a compilation and evaluation of all this data but the main part will be given focused on seasonal variations. Samples have been analysed with regard to the metals Na, K, Ca, Mg, Fe, Al, Li, B, As, Cu, Ni, Zn, Co, Cr, Cd, Pb, Mo, Sr and U. Other analysed parameters were tot-N, tot-P, bicarbonate (alkalinity), sulphate, chloride and the parameters pH, electrical conductivity and COD(Mn). Samples of bottom fauna have also been collected in Frommestabäcken. Concentration of most metals increased in the surface water while passing the Kvarntorp area. High metal concentrations were found for example in some of the groundwater samples. Such high concentrations were not observed in the samples from Frommestabäcken or Frogestabäcken, indicating for example dilution of metals or immobilisation through precipitation or adsorption. Seasonal effects on the dissolution and precipitation/adsorption of compounds were observed at all annually sampled watercourses. One of these effects was the spring- and autumn circulation of the lake Norrtorpssjön. The lake forms a thermocline during summer which causes higher concentrations of metals beneath the thermocline. During circulation these concentrations mixes throughout the depth profile which affects the amount of elements that is transported from the lake via Frogestabäcken. During winter the highest concentrations of metals are expected near the surface of the lake since the surface is colder than the rest of the water mass.