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Heavy metal pollution of aquatic ecosystems is worldwide problem with consequences on the aquatic organisms. The concentrations of selected heavy metals (Fe, Mn, Zn, Cu, Cd and Pb) were determined in liver, kidney, gills, muscle and bone of barbel (Barbus rebeli) and chub (Squalius squalius) from the river Crn Drim in Macedonia. In general, liver and kidney in both fish species contained the highest concentration of the investigated metals, while muscle showed lowest bioaccumulation of heavy metals. Analyses supported significant seasonal differences in some organs for some metals: highest value in spring-summer compared to autumn-winter period. Generally, metal concentration was higher in the barbel than chub. The concentration of metals in muscle are bellow permissible value and do not constitute any threat for human health due to the consumption of metal loaded fish.

During several botanical expeditions in the Republic of Serbia (Mts Šar-Planina and Mts Homoljske Planine), two species of the genus Viola (V. sect. Viola) were found as new for the flora of Serbia: Viola chelmea Boiss. & Heldr. in Mt. Ošljak and V. jooi Janka in Mt. Vukan. The last taxon represents a new species also for the flora of the Balkan Peninsula. The taxonomic positions, phytogeographic importance and conservation statuses of the two new plants is discussed within the scope of their newly established distribution patterns both in the Carpathians and the Balkan Peninsula.

On the basis of morphometric and karyological analysis, a new taxonomic treatment of the endemic orophytes Viola aetolica and V. elegantula is presented and two new species, V. pseudaetolica and V. kopaonikensis from the central part of the Balkan Peninsula, are described. The Balkan endemic V. pseudaetolica differs from the similar Southern Balkan endemic V. aetolica by its rather large bright yellow flowers, conspicuously denticulate and pubescent sepals and longer spur; it also shares some features with V. elegantula and V. kopaonikensis. V. kopaonikensis is a Serbian endemic plant, morphologically well separated from the closest Balkan endemic species V. elegantula by denser indumentum, relatively longer middle leaves, smaller and strictly yellow petals and relatively shorter spur. The differences among these four species are particularly pronounced when considering the ratios between petals and sepals, petals length/width and spurs length/width. Ecology, distribution and nomenclature of these two new species are also presented and discussed.

During two botanical expeditions in the Republic of Macedonia in 2017 (Mts Šar Planina and Mt. Jakupica), two plants were found that are new for the flora of this country: Campanula wanneri Rochel in Mt. Jakupica and Carduus ramosissimus Pančić in Mts Šar Planina. The plant species habitats and phytogeographic importance of these new findings were discussed within the scope of their newly established distribution patterns in the Balkan Peninsula.

The results of the investigation of radial distribution of some nutrients and heavy metals (Mg, K, Ca, Na, Fe, Cu, Cd, and Mn) in the wood of Turkey Oak (Quercus cerris L.) are presented. The goal of the presented work was to analyze the radial patterns of several bioelements and heavy metals as well as to assess the impact of the iron mining and flotation pond. For that purpose, accumulation of above mentioned metals in the tree rings of oak trees in the unpolluted and affected area was analyzed. Several series of tree rings (three consecutive years as an average) were analyzed from the period of active mining (from 1950s to late 1980s). The same analysis was performed in the tree rings in the period after the mining activities were stopped.

The paper presents the results of the rapid assessment of stream integrity of stream segments in the upper Vardar watershed in Skopje region, with an emphasis on the Vardar as the biggest and the most important watercourse in Macedonia. The river Vardar is under significant anthropogenic pressure, especially in Skopje and its surroundings. The aim of this study is to evaluate stream segments integrity by estimating the land use impact on adjacent riparian habitats, and the impact that multiscale environmental properties have on subbasin features. The results have principally been derived from field data, combined with satellite images and Corine Land Cover, which have been computer-processed with ArcGIS software and set in a model build up on Watershed Habitat Evaluation and Stream Integrity Protocol (WHEBIP). The upper Vardar basin in Skopje region has been divided into 323 subbasins and 323 stream segments as appropriate; 41 of these have been rated as streams with excellent integrity, 53 as very good, 61 as good, 72 as fair and 96 as poor. The results obtained in this study can contribute towards setting priorities for integrated management and a conservation plan for watersheds and streams in Skopje region, which is crucial since the area is characterized by a high rate of urbanization.