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The aim of this paper was to investigate whether changes in the quantity and structure of humic acids (HA) occur during bioremediation of waste mazute (heavy residual fuel oil). The effects of humification on the structure of HA were evaluated by Fourier Transform Infrared Spectroscopy (FT-IR), potentiometric titrations, the ratio of absorbances at 465 and 665 nm (E4/E6 ratio) and the ratio. Also, the quality of humification was monitored by determining parameters which are important for measuring the evolution of humic substances (HS), such as CHA/CFA (the humic acidifulvic acidratio), the rate of extraction (TE) and the index of polymerization (IP). An increase of the content of HA from 0.23% to 0.70% was observed during the bioremediation process. The FT-IR spectra and 04 ratio of HA extracted at the beginning and the end of the process indicate structural changes during the bioremediation process. The groups containing aromatic and carboxylic carbon increased, resulting in HA structures of higher aromaticity. An increase of the B4/E6 ratio during bioremediation treatment implied the enrichment of HA with functional oxygen groups. Potentiometric titrations of HA solution showed increases in the buffering and the redox capacities of HA during the bioremediation process. The results of parameters of humification showed an increase of the compositional carbon in HA at the end, compared to at the start, of bioremediation, while the carbon that belonged to fulvic acids (FA) reduced by 44%. Transformation into HA is the likely cause of this observed reduction. The TE and the IP demonstrated that humification occured during the bioremediation process. According to the available data, this is the first report on synthesis of HS during bioremediation of petroleum hydrocarbons. (C) 2017 Published by Elsevier Ltd.

A survey was made to analyze the geostatistical (GIS) distribution of the health risk of toxic trace metal(loid)s in the industrial soil located in the facility of an abandoned paints manufacturing company. A total of eighty surface soil samples were collected, and their concentrations determined. The mean concentration values of the elements were 7.8; 2.7; 55; 49; 0.21; 56; 114; and 239 mg/kg for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively. There was no non-carcinogenic health risk from the soil samples for adults, but it was hazardous soil for children with the excess lifetime cancer risk (ELCR) values exceeding the reference value of 10-4 for all studied samples. Most contributing toxic metal(loid)s to non-carcinogenic risk were Cr and As, whereas Pb and As were most responsible for cancer risk. Geospatial mapping of the hazard index (HI) and ELCR localized different hotspots seriously polluted by toxic metal(loid)s, which pose a significant risk in the area. These hotspots coincided with the evidence of transport-related activities and spillage of chemicals in the past. This GIS spatial distribution study could be a valuable aid in remediation planning.

The survey results of an atmospheric deposition of major, minor and trace elements using the moss biomonitoring technique are given for the vicinity of the largest thermal power plant in Serbia. The mosses of genus Brachythecium sp. and species Kindbergia praelonga (Hedw) Ochyra, both pleurocarpous, were favoured. The concentrations of 22 elements were determined in moss samples using different spectrometric techniques depending on the sensitivity needed. Elevated concentrations of As, Cd, Co, Hg, Ni and V were found in the vicinity of the thermal power plant. The results obtained were chemometrically treated by cluster analysis, which grouped the elements into three clusters based on common patterns in their concentrations.

The content of trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn) in surface soils in the area surrounding the largest coal-fired power plant in Serbia was determined to assess the contribution of emissions to pollution. Analysis of mutual associations between the trace elements and their correlation with soil particle size fractions indicated anthropogenic origin at most sampling sites. Enrichment factor analysis confirmed these findings. Common patterns in trace element concentrations of the analysed soils were identified by hierarchical cluster analysis. Explanatory spatial analysis, used for characterization and mapping of spatial variability patterns, revealed the highest concentrations of trace elements in areas in predominant wind directions. (C) 2012 Elsevier B.V. All rights reserved.

The Mediterranean blue mussel Mytilus galloprovincialis was used as a pollution level indicator in the Boka Kotorska Bay of the southeastern Adriatic on the Montenegrin coast. The ever-increasing urbanization and industrialization, combined with a poor sewage system, an increase in both marine and inland traffic, as well as insufficient water circulation in the Bay itself have resulted in some level of pollution. Since heavy metals are extremely toxic and do not easily undergo biodecomposition, the results of this study supply valuable information concerning the metal pollution of the marine environment in Boka Kotorska Bay. The concentrations of the investigated metals and nonmetals accumulated in the mussels were determined during the fall of 2007 using Atomic Absorption Spectroscopy (AAS) for Cr, Mn, Co, Ni, Cu, Cd, Hg, Pb, Sn and V, and Energy Dispersive X-ray Fluorescence (ED-XRF) to determine the concentrations of Fe, Zn, Si, P, S, Cl, K and Ca. ED-XRF was also used to determine the levels of non-metals and elements present in high concentrations. Comparing the data from this study in relation to data from other regions for Mytilus galloprovincialis, the mussel sampled from the Boka Kotorska Bay showed a moderate level of pollution.

The specific activities of natural radionuclides ((40)K, (226)Ra and (232)Th) and Chernobyl-derived (137)Cs were measured in soil profiles representing typical soil types of Belgrade (Serbia): chernozems, fluvisols, humic gleysols, eutric cambisols, vertisols and gleyic fluvisols. The influence of soil properties and content of stable elements on radionuclide distribution down the soil profiles (at 5 cm intervals up to 50 cm depth) was analysed. Correlation analysis identified associations of (40)K, (226)Ra and (137)Cs with fine-grained soil fractions. Significant positive correlations were found between (137)Cs specific activity and both organic matter content and cation exchange capacity. Saturated hydraulic conductivity and specific electrical conductivity were also positively correlated with the specific activity of (137)Cs. The strong positive correlations between (226)Ra and (232)Th specific activities and Fe and Mn indicate an association with oxides of these elements in soil. The correlations observed between (40)K and Cr, Ni, Pb and Zn and also between (137)Cs and Cd, Cr, Pb and Zn could be attributed to their common affinity for clay minerals. These results provide insight into the main factors that affect radionuclide migration in the soil, which contributes to knowledge about radionuclide behaviour in the environment and factors governing their mobility within terrestrial ecosystems.

Bone char powder, composed mainly of poorly crystalline hydroxyapatite (Ca(10)(PO(4))(6)(OH)(2)), carbon and CaCO(3), has potential applicability in the removal of Co(2+) ions from contaminated effluents. In the present study, the influence of process parameters: particle size, agitation speed, initial pH and initial sorbate concentration, onto kinetics and mechanism of Co(2+)sorption was studied and discussed. In order to describe and compare time evolution of the process under different conditions, the experimental data were analyzed using pseudo-first, pseudo-second and Vermeulen's kinetic models. Generally, experimental results were best fitted with the pseudo-second-order model, which accurately predicted the equilibrium sorbed amounts. The pseudo-second-order rate constant was the most influenced by variations in initial metal concentration and pH, in the investigated ranges. The conclusions about sorption mechanism were derived based on Co(2+) amounts sorbed during time, as well as considering solution pH changes, changes of Ca(2+) amounts released into liquid phase and Ca(2+)/Co(2+) molar ratios. It was concluded that rapid sorption stage was governed by surface complexation reactions, whereas the contribution of the ion-exchange mechanism increased with time and became more significant in the second, slower phase. Experimentally determined maximum sorption capacity towards Co(2+), under optimal conditions, was found to be 0.38 mmol/g. The results show that bone char represents cost-effective alternative to synthetic hydroxyapatite sorbent.