## 2 Study Area  
The study area covers 6200 ha and is located directly at the eastern border of the Arcelor Mittal (formerly W. Lenin) steelworks in the Krakow area (southern Poland, Central Europe). The study area was subjected to almost 70 years of the direct impact of the steelworks. The steelworks mainly emit dust-gas pollutants, which reach the ground surface in the form of wet and dry precipitation (Figure 1). The main pollutants are gaseous sulphur compounds and heavy metals (Cr, Cu, Fe, Mn, Ni, Pb, Zn) occurring in various chemical forms (including elemental form). The technological development of the steelworks and changes in the volume of steel production directly affected the emission of pollutants. In the initial years of the steelworks existence (mainly 1950s to 1980s), the emission of pollutants to the environment was very high. At present, the modern technologies applied have considerably reduced it. However, the pollutants emitted during many years of the steelworks existence still constitute a serious environmental problem and the explanation of the processes they undergo in the water and soil environment is a key issue for the assessment of the condition of the natural environment in the studied area. Among the pollutants emitted by the steelworks, heavy metals are potentially the greatest hazard to the environment. The following were selected for detailed analyses: Cr, Cu, Fe, Mn, Ni, Pb and Zn, while the main source of these metals in the study area was/is the emission from the steelworks. The study area is characterised by high homogeneity of soil types--the parent rocks of soils are mainly Quaternary loess sediments related to the Vistula glaciation. Soils developed on outcrops of Cretaceous marls (Figure 2) occur only subordinately in small areas of the NE part of the study area. Besides the mentioned primary loess deposits, alluvial and deluvial deposits occur in narrow stream valleys. Very small fragments of stream valleys are occupied by mud and peat deposits. The areas of particular types and subtypes calculated on the basis of planimetric measurements (Table 1) confirm the domination of soils developed on loess. There is also an underground water intake located in the immediate vicinity of the steelworks, which is used as a source of drinking water. This intake consists of 13 wells exploiting a shallow valley water-bearing horizon. The aquifer is mainly composed of alluvial sediments of various grains. Within the studied area, the aeration zone of the aquifer is formed mainly by poorly permeable loess sediments with a thickness of several metres on average. Consequently, the aeration zone is characterised by high retention capacity due to its considerable thickness and poor permeability properties, which determines the relatively long infiltration time of rainwater. The average infiltration velocity value obtained on the basis of interpretation of natural (SO\({}_{4}\)\({}^{2-}\) ions) and artificial (Br\({}^{-}\) ions) tracer movements in the aeration zone profile is 0.53 m-year\({}^{-1}\)[42; 43; 44; 45; 46; 47]. As a result, at least some part of heavy metals may be absorbed. It is significant because infiltration waters are the basic source of supply for the aquifer system in the study area. The study area is predominantly used for agricultural purposes. Arable fields cover the vast majority of the area. The agricultural character of land use has a major impact on soil conditions, especially on pH and humus content. This determines the ability of the soil to retain contaminants. Heavy metals are subject to a number of different physical and chemical reactions in the soil layer, which can cause significant delays in their migration into the aquifer system and often even stop their migration [30]. Heavy metal concentrations in soils also depend on the type of soil itself. In the studied area the soils are mainly characterised by neutral and alkaline reactions, which favour retention of heavy metal migration [48].