No abstract

The concentrations of As, Cd, Cr, Co, Cu, Ni, Pb, and Zn in water and sediment samples from Trepça and Sitnica rivers were determined to assess the level of contamination. Six water and sediment samples were collected during the period from April to July 2014. Most of the water samples was found within the European and Kosovo permissible limits. The highest concentration of As, Cd, Pb, and Zn originates primarily from anthropogenic sources such discharge of industrial water from mining flotation and from the mine waste eroded from the river banks. Sediment contamination assessment was carried out using the pollution indicators such as contamination factor (CF), degree of contamination (Cd), modified degree of contamination (mCd), pollution load index (PLI), and geo-accumulation index (Igeo). The CF values for the investigated metals indicated a high contaminated nature of sediments, while the Cd values indicated a very high contamination degree of sediments. The mCd values indicate a high degree of contamination of Sitnica river sediment to ultrahigh degree of contamination of Trepça river sediment. The PLI values ranged from 1.89 to 14.1 which indicate that the heavy metal concentration levels in all investigated sites exceeded the background values and sediment quality guidelines. The average values of Igeo revealed the following ranking of intensity of heavy metal contamination of the Trepça and Sitnica river sediments: Cd > As > Pb > Zn > Cu > Co > Cr > Ni. Cluster analysis suggests that As, Cd, Cr, Co, Cu, Ni, Pb, and Zn are derived from anthropogenic sources, particularly discharges from mining flotation and erosion form waste from a zinc mine plant. In order to protect the sediments from further contamination, the designing of a monitoring network and reducing the anthropogenic discharges are suggested.

The aim of this study was to extract the wood biomass fly ash fractions by a three-stage sequential extraction method for acetic acid and ion exchangeable (BCR 1), hydroxylamine hydrochloride reduction (BCR 2), and hydrogen peroxide oxidation (BCR 3) fractions in order to access the leaching behavior of this residue. The fly ash was collected as a by-product from the processing of mixed wood biomass in Udbina combustion facility, Croatia. Concentrations of several elements (As, Cd, Cr, Cu, Ni, Pb and Zn) in all extracts were determined by inductively coupled plasma atomic emission spectrometry. The acidic exchangeable form of the metals was used to evaluate the potential ecological risk of biomass fly ash. According to calculated potential ecological risk index, it is confirmed that mobility of Ni and As has major environmental impact. However the results of potential ecological risk show that biomass fly ash had a low risk.

Abstract. Jarosite waste, originating from zinc extraction industry, is considered hazardous due to the presence and the mobility of toxic metals that it contains. Its worldwide disposal in many tailing damps has become a major ecological concern. Three different methods, namely modified Synthetic Precipitation Leaching Procedure (SPLP), three-stage BCR sequential extraction procedure and Potential Ecological Risk Index (PERI) Method were used to access the ecological risk of jarosite waste disposal in Mitrovica Industrial Park, Kosovo. The combination of these methods can effectively identify the comprehensive and single pollution levels of heavy metals such as Zn, Pb, Cd, Cu, Ni and As present in jarosite waste. Moreover, the great positive relevance between leaching behavior of heavy metals and F1 fraction was supported by principal component analysis (PCA). PERI results indicate that Cd showed a very high risk class to the environment. The ecological risk of heavy metals declines in the following order: Cd>Zn>Cu>Pb>Ni>As.

During the zinc production process from sulfidic ores, the jarosite residue is produced within the precipitate containing ammonia, iron, zinc and other metal sulfates. The process yield jarosite which has been dumped as a waste despite its acidity presents environmental hazard while high content of iron, zinc, lead, cadmium and other heavy metal compounds additionally presents further utilization possibilities. In this paper, the thermal decomposition of jarosite tailing waste collected in Mitrovica Industrial Park situated in Kosovo is investigated in order to get better understanding of its possible utilization as a source of valuable raw materials. Samples of jarosite tailing waste were taken at depths of 0.2, 1 and 2 m. The samples were characterized by means of powder X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectrometer (SEM/EDS), thermogravimetric analysis (TG) and differential thermal analysis (DTA). The results obtained from XRD confirmed the presence of ammonium jarosite in the investigated tailing waste samples. Results of TG-DTA indicated that the decomposition of jarosite samples occurs in four consecutive stages up to the temperature of 500°C. On behalf of SEM/EDS analysis, jarosite samples yield poorly defined micron-sized morphology associated with high content of Fe and S, but also Pb, Cd, Zn and As. Composition of jarosite tailing waste was found depth dependent which should facilitate jarosite waste reuse at the investigated site. Graphical Abstract 10 20 30 40 50 60 70 80 2θ°/CuKα CPS/a.u. S1 S2 S3 Jarosite sample 1, depth= 20 cm Jarosite sample 2, depth= 1 m Jarosite sample 3, depth= 2 m Jarosite,