Aerial parts of Hypericum perforatum L. (Hypericaceae) were collected from five wild populations in Kosovo, with aim to investigate the chemical composition and natural variation of essential oils between wild populations. This species could be considered of economic potential as it is widespread in Kosovo, on the other hand H. perforatum is one of the best-known medicinal herbs used in Kosovo folk medicine. Essential oils were obtained by steam distillation and analysed by GC-FID and GC-MS. Sixty-seven components were identified. The yields of essential oils differed depending on the population and ranged from 0.04 to 0.26% based on dry weight. The aerial parts of H. perforatum were characterized by the following main constituents: 2-methyl-octane (1.1-15.5%), α-pinene (3.7-36.5%), β-caryophyllene (1.2-12.4%), caryophyllene oxide (3.3-17.7%) and n-tetradecanol (3.6- 10.4%). Hierarchical cluster analysis revealed that the concentration of components depends on the origin of the plant populations, thus α-pinene and 2-methyl-octane were present in the highest concentration in population originating from Gjakove, Prizren and Ferizaj, whereas in the populations originating from Peje and Prishtine the most abundant constituents were caryophyllene oxide, β-caryophyllene and n-tetradecanol. Further investigation is needed to establish the natural variability and chemopolymorphism of this species in the territory of Kosovo, which should be supported by molecular level analyses.

The purpose of this study was to determine the quality of water in lake Batllava, through which, a part of the population of the Pristina region is supplied with drinkable water. Lake Batlava is a lake built in the 1970s. This lake is located in the village of Batlava in the municipality of Podujeva. The supply of this lake with water is made from the Brvenica river. Monitoring was finished during the period from December 2020 to May 2021. The sample were taken in three championic places: at the entrance of the lake, in the middle and in the spill, on two levels, in the surface and at depth of 30 cm. The analyzed microbiological parameters are: total coliforms, fecal coliforms, fecal streptococci and aerobic mesophilic bacteria. The physical-chemical parameters are: dissolved oxygen, saturation with O 2 , water temperature, pH value, electrical conductivity, total soluble matter, total suspended matter, turbidity, chemical demand for oxygen, biochemical demand for oxygen, total organic carbon, nitrate, total solidity of calcium, magnesium, ammonia ion, chloride, sulphates, fluurite, M-alkalines, bicarbonates and heavy metals, such as: Fe, Pb, Mn, Cu, Cd. The results showed that most physical-chemical and microbiological parameters are within the limit allowed by the WHO and EPA, except in some cases where during the precipitation season there have been several overruns and for this reason, it is recommended to take monthly monitoring of the water of Lake Batllava to achieve a real assessment.

Through this research, we have carried out monthly water quality monitoring in Lake Badovci using microbiological, physico-chemical and diatomic indicators of algae, in order to provide credible data regarding the quality of water in Lake Badovci. The monitoring took place between December 2020 and May 2021. Three sample sites were selected: at the entrance, in the center and in the catchment area. Total coliforms, fecal coliforms, fecal streptococci, aerobic mesophyllic bacteria, and actinomycetes were all analyzed microbiologically. Dissolved oxygen, oxygen saturation, water temperature, pH value, electrical conductivity, total dissolved solids, total suspended solids, turbidity, chemical oxygen demand, biochemical oxygen demand, total nitrates organic carbon, total hardness, total hardness of calcium and magnesium, chlorides, fluorides, M-alkalinity, bicarbonates and heavy metals such as Fe, Pb, Mn, Cu and Cd. The highest levels of physicochemical and microbiological indices were found in January and lasted until February at the first sample location. This is due to the torrential rains that have resulted in increased inflows from the rivers that flow into this lake. According to diatomic indices (Descry, Rott SI, IDG, IPS, IBD, and CEE), water has an excellent ecological status and is oligo-mesotrophic, except for some indices that showed a moderate ecological status and mesotrophic level. The activities of monitoring, planning, and management of the waters in this lake, which is used for drinking water supply, washing, and fishing, have to be done regularly.