To investigate and assess the effects of land use and its changes on concentrations of heavy metals (Pb, Zn, Cd, Cu, Mn, Ni, Fe) in the tributary of drinking water reservoir catchment, soils of different land use types (forest, arable land, meadows and pastures, residential areas), suspended sediment and bottom sediment were collected. Heavy metals were analyzed using atomic absorption spectrophotometry (AAS). The metal distribution pattern was observed, where Zn and Cd could be considered as main metal contaminants. The variation in the concentration level of Zn and Cd in studied soils showed the impact of pollution from anthropogenic activities. Also some seasonal variations were visible among the suspended sediment and bottom sediment samples which could be associated with land agricultural practices or meteorological conditions. The sediment fingerprints approach used for determining sources of the suspension in the catchment showed (Kruskal-Wallis H test, p<0.05), that only Mn and Ni were not able to be distinguished among the potential sediment sources. A multiple linear regression model described the relationship between suspended sediment and 4 types of soil samples. The results related suspended composition mostly to the samples from the residential land use. Considering the contemporary trend of observed changes in land use resulting in conversion of agricultural areas into residential and service structures these changes can be essential for the contamination of aquatic environment. This situation is a warning sign due to the rapid industrialization, urbanization and intensive agriculture in this region what can significantly affect the drinking water quality.

FA discharged from the wastewater treatment plant were extracted from purifi ed effl uents for the quantitative

and qualitative analysis. The treated sewage from municipal treatment plants was acidifi ed to pH <2 and extracted

with ion exchange resins in a laboratory column. After desorption with NH4

OH, the fulvic acids were condensed

under vacuum and tested for mass performance, UV-VIS light spectra, IR absorption spectra, elementary composition

and other elements. Their structure was analysed and compared to FA present in surface waters and in sewage treated

in other sewage treatment plants based on the authors’ own research and the literature data. The concentration of

FA in the treated sewage was 5.2 mg/L. There is a high interdependence between the IR spectrum analysis in the

visible light and the elementary composition of FA extracted from different environments, confi rming the conclusions

pertaining to the structure and properties of the acids being tested. The longer sewage is subjected to a biological

treatment process, the greater the degree of aromatic condensation and humus maturity of the FA contained within it.

FA contained in the sewage treated in the three biological sewage treatment plants have the ratio A2

/A3

(the ratio of the

absorbance of light with the wavelength of 250 and 300 nm) equal to the value 1.7. There is a high interdependence

between the IR spectrum analysis in the visible light and the elementary composition of FA extracted from different

environments, confi rming the conclusions pertaining to the structure and properties of the acids being tested.