The impact of changes in physical-chemical conditions and selected treatments on the mobility of metals in sediment / water systems

U radu je ispitana distribucija metala u sistemu sediment/voda na najugroženijim vodotocima u AP Vojvodini. Na osnovu dobivenih podataka urađena je procena rizika na osnovu analize porne vode, kiselog volatilnog sulfida i simultano ekstrahovanih metala i sekvencijalne ekstrakcione procedure. Procena mobilnosti metala u sistemu sediment/voda određena je promenom fizičko-hemijskih uslova u realnom sistemu (vodotok) i u laboratorijskim uslovima. Ispitana je efikasnost in-situ (aeracijom sistema sediment/voda) i ex-situ remedijacije sedimenta metodama termičkog tretmana i solidifikacije/stabilizacije. Rezultati su ukazali da u svakom vodotoku i zaštićenoj zoni postoji lokacija u kojoj je sediment barem po jednom metalu klasifikovan (holandski sistem klasifikacije sedimenata) kao zagađen (klasa 3) ili izuzetno zagađen sediment (klasa 4). Generalno, kvalitet sedimenta manjih vodotoka (Krivaja, Nadela, Kudoš, Veliki Bački kanal i Begej) je lošiji u odnosu na ostale ispitivane vodotoke. Procena dostupnosti metala u sedimentu Velikog Bačkog kanala ukazala je da na svakom ispitivanom profilu postoji minimum jedan metal i jedna metoda koja definiše sediment kao visoko rizičan. Takođe je zaključeno da je sediment na delu od 2+000 do 4+900 km zagađeniji, jer postoji veći broj metala i metoda koji ga definišu kao visoko rizičnim. Ovako dobijeni rezultati ukazuju da nije dovoljan jednostavan i samo jedan pristup u oceni kvaliteta sedimenta i proceni rizika koji metali mogu da ispolje u akvatičnom ekosistemu. Ukazano je da pomeranje sedimenta (npr. otvaranja ustave), dovodi do promene fizičkohemijskih uslova u sistemu sediment/voda, resuspenzije i transporta sedimenta. Usled ovih promena povećava se dostupnost metala i dolazi do povećanja njihove koncentracije u vodenoj fazi čime se znatno povećava rizik i mogućnost ispoljavanja negativnih efekata na akvatični ekosistem. U slučaju resuspenzije sedimenta u sistemu sediment/voda pronađena je zavisnost između koncentracije metala u suspendovanim materijama i vodi od sadržaja određenih frakcija u suspendovanim materijama (sadržaj organskih materija i frakcije do 63 μm). Remedijacione tehnike često su ekonomski neprihvatljive zbog velike zapremine zagađenog sedimenta. Ukazano je da primena in-situ aeracije, omogućava smanjenje količine sedimenta (čime se smanjuju troškovi eventualno naknadnog tretmana sedimenta), a da je tretman solidifikacije/stabilizacije sedimenta sa glinom i termičke remedijacije zadovoljavjući sa aspekta izluživanja metala. Dobijeni rezultati izvedenih testova izluživanja ukazali su na moguću primenu ovih tretmana u pogledu rešavanja problema sedimenta koji je zagađen metalima, bilo u pogledu sigurnog odlaganja na deponiju ili u smislu njegove upotrebe kao dodatka pri proizvodnji građevinskog materijala (opeke), osnove za puteve, uređenje obale (nasipa) itd. Na taj način mogu se znatno umanjiti troškovi izmuljivanja i manipulacije kontaminiranog sedimenta, a sama remedijacija učiniti mnogo prihvatljivijomThis work investigates the distribution of metals in the sediment / water systems of the most endangered rivers in Vojvodina. Utilizing the data obtained, risk assessments are carried out based on analysis of pore water, acidic volatile sulphides and simultaneously extracted metals and sequential extraction procedure. The assessment of metal mobility in the sediment / water system is determined by the changing physical and chemical conditions in real systems (waterways) and under laboratory conditions. The effectiveness of in-situ (aeration of sediment / water) and ex-situ remediation of sediment by thermal treatment methods and solidification / stabilization are investigated. The results show that in each waterbody and protected area, certain locations have sediment which for at least one metal, is classified (by the Dutch system of sediment classification ) as polluted (class 3) or highly polluted (class 4). In general, the quality of sediment in smaller rivers (Krivaja, Nadela, Kudoš, Veliki Bački canal and Begej) is inferior to the other rivers studied. Assessment of the metals availability in the sediments of the Veliki Bački canal indicates that in each profile examined, at least one metal and one method defines the sediment as very hazardous. It is also shown that the sediment at the section from 2 +000 to 4 +900 km is the most polluted, with a number of metals and methods that define it as a high risk. The results indicate that it is inadequate to have a simple singular approach to sediment quality assessment and the assessment of the risks posed by metals detected in aquatic ecosystems. This work shows that sediment movement (e.g. from opening a sluice gate) leads to changes in the physical-chemical conditions of the sediment / water system, with resuspension and sediment transport. These changes increase metals availability and increase their concentrations in the aqueous phase, significantly increasing the posed risk and the possibility of adverse effects on aquatic ecosystems. In the case of sediment resuspension in the sediment / water system, a relationship was found between the concentration of metals in suspended matter and the concentration in the water for certain fractions of suspended matter (organic matter content and the fraction up to 63 μm). Remediation techniques are often not economically viable due to the large volume of contaminated sediments involved. It is shown that the implementation of in-situ aeration reduces the amount of sediment (which reduces the costs of subsequent sediment treatment), and that solidification / stabilization treatment with clay and thermal remediation results in satisfactory remediation with respect to metals leaching. Leaching test results show the potential of these treatments to solve the problem of sediments which are contaminated with metals, either in terms of safe disposal in landfill or in terms of its use as a supplement in the production of building materials (brick), as road foundation, or for river bank reinforcement (dams), etc.. Thus, the costs of dredging and manipulating contaminated sediments can be significantly reduced, making remediation itself much more applicable

Adsorption kinetics and mechanism analysis of cyan printing dye on polyethylene microplastics

Printing on polymer materials might result with generation of coloured wastewater, enriched with a certain amount of microplastics in a form of polyethylene or polypropylene. In that way, microplastics may acquire the function of carriers of synthetic dyes, heavy metals and other polluting substances. In this paper, kinetics and adsorption mechanism of printing Cyan dye on polyethylene (powdered and granulated), as one of the most common types of microplastics, were investigated. The experiments were performed in a batch mode, in laboratory conditions. Based on the obtained results, a similar adsorption rate degree of selected printing dye was determined on granulated (adsorbed amount was 48.04 µg/g) and powdered material (adsorbed amount was 44.32 µg/g). The adsorption data were fitted well by pseudo-second-order kinetics, while isotherm studies were evaluated using two models: Langmuir and Freundlich. Freundlich and Langmuir equations showed similar performances to fit the solid/liquid distribution of Cyan dye on powdered polyethylene (R2 = 0.987), whereas Langmuir equation showed slightly better performances for granulated polyethylene than Freundlich equation

Characterization of natural zeolite (clinoptilolite) as one of the high cation exchange capacity geopolymer material

The aim of this research is to subject one of the specific and locally used natural zeolite (clinoptilolite) from Vranjska Banja, Serbia with high cation exchange capacity. Mineralogical - X-Ray Diffraction Analysis (XRD), Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) and determination of cation exchange capacity (CEC) were investigated. Results showed homogenous structure with dominant clinoptilolite - heulandite type zeolites as most abundant minerals. The important aspect of this research is possibility of wider usage of natural zeolite-clinoptilolite due to cost-efficiency aspects of this natural material that can be exploited in large amount from several Serbian deposits e.g. “Zlatokop” (Vranjska Banja) and “Igroš Vidojević” (Brus), Serbia. The present of higher, but also extremely concentration of heavy metals in Pannonian, Internal Dinarides and wider European region lead us to boost novel high performance but economically viable techniques. The starting points are geochemical characterization of novel geo- materials before further water-treatment implementation

The impact of changes in physical-chemical conditions and selected treatments on the mobility of metals in sediment / water systems

U radu je ispitana distribucija metala u sistemu sediment/voda na najugroženijim vodotocima u AP Vojvodini. Na osnovu dobivenih podataka urađena je procena rizika na osnovu analize porne vode, kiselog volatilnog sulfida i simultano ekstrahovanih metala i sekvencijalne ekstrakcione procedure. Procena mobilnosti metala u sistemu sediment/voda određena je promenom fizičko-hemijskih uslova u realnom sistemu (vodotok) i u laboratorijskim uslovima. Ispitana je efikasnost in-situ (aeracijom sistema sediment/voda) i ex-situ remedijacije sedimenta metodama termičkog tretmana i solidifikacije/stabilizacije. Rezultati su ukazali da u svakom vodotoku i zaštićenoj zoni postoji lokacija u kojoj je sediment barem po jednom metalu klasifikovan (holandski sistem klasifikacije sedimenata) kao zagađen (klasa 3) ili izuzetno zagađen sediment (klasa 4). Generalno, kvalitet sedimenta manjih vodotoka (Krivaja, Nadela, Kudoš, Veliki Bački kanal i Begej) je lošiji u odnosu na ostale ispitivane vodotoke. Procena dostupnosti metala u sedimentu Velikog Bačkog kanala ukazala je da na svakom ispitivanom profilu postoji minimum jedan metal i jedna metoda koja definiše sediment kao visoko rizičan. Takođe je zaključeno da je sediment na delu od 2+000 do 4+900 km zagađeniji, jer postoji veći broj metala i metoda koji ga definišu kao visoko rizičnim. Ovako dobijeni rezultati ukazuju da nije dovoljan jednostavan i samo jedan pristup u oceni kvaliteta sedimenta i proceni rizika koji metali mogu da ispolje u akvatičnom ekosistemu. Ukazano je da pomeranje sedimenta (npr. otvaranja ustave), dovodi do promene fizičkohemijskih uslova u sistemu sediment/voda, resuspenzije i transporta sedimenta. Usled ovih promena povećava se dostupnost metala i dolazi do povećanja njihove koncentracije u vodenoj fazi čime se znatno povećava rizik i mogućnost ispoljavanja negativnih efekata na akvatični ekosistem. U slučaju resuspenzije sedimenta u sistemu sediment/voda pronađena je zavisnost između koncentracije metala u suspendovanim materijama i vodi od sadržaja određenih frakcija u suspendovanim materijama (sadržaj organskih materija i frakcije do 63 μm). Remedijacione tehnike često su ekonomski neprihvatljive zbog velike zapremine zagađenog sedimenta. Ukazano je da primena in-situ aeracije, omogućava smanjenje količine sedimenta (čime se smanjuju troškovi eventualno naknadnog tretmana sedimenta), a da je tretman solidifikacije/stabilizacije sedimenta sa glinom i termičke remedijacije zadovoljavjući sa aspekta izluživanja metala. Dobijeni rezultati izvedenih testova izluživanja ukazali su na moguću primenu ovih tretmana u pogledu rešavanja problema sedimenta koji je zagađen metalima, bilo u pogledu sigurnog odlaganja na deponiju ili u smislu njegove upotrebe kao dodatka pri proizvodnji građevinskog materijala (opeke), osnove za puteve, uređenje obale (nasipa) itd. Na taj način mogu se znatno umanjiti troškovi izmuljivanja i manipulacije kontaminiranog sedimenta, a sama remedijacija učiniti mnogo prihvatljivijomThis work investigates the distribution of metals in the sediment / water systems of the most endangered rivers in Vojvodina. Utilizing the data obtained, risk assessments are carried out based on analysis of pore water, acidic volatile sulphides and simultaneously extracted metals and sequential extraction procedure. The assessment of metal mobility in the sediment / water system is determined by the changing physical and chemical conditions in real systems (waterways) and under laboratory conditions. The effectiveness of in-situ (aeration of sediment / water) and ex-situ remediation of sediment by thermal treatment methods and solidification / stabilization are investigated. The results show that in each waterbody and protected area, certain locations have sediment which for at least one metal, is classified (by the Dutch system of sediment classification ) as polluted (class 3) or highly polluted (class 4). In general, the quality of sediment in smaller rivers (Krivaja, Nadela, Kudoš, Veliki Bački canal and Begej) is inferior to the other rivers studied. Assessment of the metals availability in the sediments of the Veliki Bački canal indicates that in each profile examined, at least one metal and one method defines the sediment as very hazardous. It is also shown that the sediment at the section from 2 +000 to 4 +900 km is the most polluted, with a number of metals and methods that define it as a high risk. The results indicate that it is inadequate to have a simple singular approach to sediment quality assessment and the assessment of the risks posed by metals detected in aquatic ecosystems. This work shows that sediment movement (e.g. from opening a sluice gate) leads to changes in the physical-chemical conditions of the sediment / water system, with resuspension and sediment transport. These changes increase metals availability and increase their concentrations in the aqueous phase, significantly increasing the posed risk and the possibility of adverse effects on aquatic ecosystems. In the case of sediment resuspension in the sediment / water system, a relationship was found between the concentration of metals in suspended matter and the concentration in the water for certain fractions of suspended matter (organic matter content and the fraction up to 63 μm). Remediation techniques are often not economically viable due to the large volume of contaminated sediments involved. It is shown that the implementation of in-situ aeration reduces the amount of sediment (which reduces the costs of subsequent sediment treatment), and that solidification / stabilization treatment with clay and thermal remediation results in satisfactory remediation with respect to metals leaching. Leaching test results show the potential of these treatments to solve the problem of sediments which are contaminated with metals, either in terms of safe disposal in landfill or in terms of its use as a supplement in the production of building materials (brick), as road foundation, or for river bank reinforcement (dams), etc.. Thus, the costs of dredging and manipulating contaminated sediments can be significantly reduced, making remediation itself much more applicable

Impact assessment wastewater discharge on water quality DTD canal Bečej-Bogojevo

Pressure and impact analysis requires information on the main drivers and changes in conditions. In order to analyze such pressures and impacts, each river basin requires: an analysis of its characteristics, a review of the impact of human activity on the status of the surface water and an economic analysis of water use. Pressure and impact analysis plays a central role in the planning of river basin management. The quality of the stream at any point depends on several major factors: lithology of the basin, weather conditions, climate, and human impacts. Most of the polluters are located in the big cities next to canal DTD Bečej-Bogojevo canal (Odzaci,Vrbas, Srbobran, Becej). Per year, 2900000 m3 of wastewater was discharged into the Bečej-Bogojevo section of the DTD canal: 1,4 tCOD, 0,8 0tBOD, 260 kg of nitrogen, 19 kg of phosphorus and 282 kg of suspended solids. Of the total volume of wastewater, 20% comes from industry and 80% from municipal wastewater. Most of the wastewaters from the studied polluters is discharged untreated or insufficiently treated (only primary treatment). This poor quality wastewater threatens the receipients into which its is discharged. Comparison of the wastewater quality results to the Decree on emission limits and deadlines for their achievement, shows that many polluters exceed the limits for all parameters (COD, BOD, nitrogen, phosphorus, suspended solids). On the basis of the physico-chemical analysis of the water from the DTD Bečej-Bogojevo canal it can be concluded that the water quality is unsatisfactory. According to the national legislation, the water quality exceeds the values for good potential streams for most parameters at all sampling locatio dissolved oxygen, organic matter and nutrients). Thus, we can conclude that the water in the studied section of the DTD Bečej-Bogojevo canal does not meet the criteria for "good ecological potential". The most vulnerable locations are downstream of the Vrbas and downstream of the Bečej, while the best quality canal water is at the furthest upstream location (CS Bogojevo). Risk assessment based on monitoring results indicates that the water of the studied section of the DTD Bečej-Bogojevo canal is probably at risk of failing to meet the objectives of the Water Framework Directive, as 33% of the analyzed parameters to calculate specific risk ratios were greater than 1, and thus fall into the category of pollutants medium risk. In order to achieve the quality (to achieve good status and good potential), there must be a response from industrial producers, which consists primarily of comprehensively understanding the problems and implementing measures to minimize the impact of these problems. [Projekat Ministarstva nauke Republike Srbije, br. TR37004

A contribution towards improving the applicability of the Myriophyllum aquaticum sediment contact test

Abstract Background Whole sediment contact tests provide realistic exposure scenarios, but the inherent properties of sediments may play a significant role in organism’s response and interfere with result interpretation. Recently, a sediment contact test with a rooted aquatic macrophyte Myriophyllum aquaticum has been standardized. The present study aims to distinguish between effects of basic sediment properties and sediment-bound pollutants on M. aquaticum growth and evaluate the method as a tool in sediment quality assessment. Tests with artificial sediments with different organic matter, sand and clay content, as well as freshwater sediments with different levels of contamination were conducted. Results Results were based on comparison to the standard artificial control sediment. Organic matter content and grain size distribution in different variants of artificial sediments significantly affected M. aquaticum growth. Growth was impaired in formulations with low (1%) and high (10%) organic matter content, while better growth of plants compared to control was recorded in artificial samples with higher fine particles content. Because of the presence of unmeasured pollutants in freshwater sediments and inherent sediment properties, results of the M. aquaticum sediment contact tests were not always in accordance with the results of chemical analysis. Whorl, shoot and root parameters had different variability and showed a particular growth pattern in natural sediments. If the threshold of 20% for sediment toxicity is applied, then about 60% of tested natural sediments may be considered as toxic. As sediment structure may influence plant growth, this interpretation may be false as the physico–chemical properties of the control sediment used for comparison are considerably different from the properties of natural sediments. Conclusions Since inherent properties showed a significant effect on plant growth, the use of suitable controls more similar to tested natural sediments is advisable. To avoid over-, but also under-estimations, the use of the strict toxicity threshold of 20% or even higher inhibition for this test can be recommended, provided the statistical power of the test is high. The results of this study might contribute to the ongoing process of including effect-based methods in water quality monitoring under the Water Framework Directive

Solidification/stabilization of metal polluted sediment of Krivaja river

The Krivaja River is the longest natural water body (109 km) that flows completely within the borders of Serbian province of Vojvodina. In the absence of national legislation, the sediment quality was assessed in accordance with the Dutch classification methodology. It was found that the river sediment is highly contaminated with copper and zinc (192 mg kg-1 and 1218 mg kg-1 respectively), and as such is an extreme risk to the environment and human health. The solidification/stabilization (S/S) treatment with local clay, that has high capacity of cation exchange 70.2 meq/100 g and specific surface area of 630 m2 g-1, was employed for remediation of the contaminated sediment. The sequential extraction procedure showed that the copper and zinc have medium risk for the environment, with the percentage in the carbonate fraction of 18 and 22% respectively. The results of sequential extraction are not in full agreement with the results of pseudo-total metal concentration in the sediment, which only confirms that the total metal concentration is not sufficient to define the real danger to the environment. Based on the pseudo-total metals concentration, the sediment is of Class 4 (Dutch standards). However, judging from the results of sequential extraction, the metals show medium risk. Obviously, these results have to be taken into account in the assessment of the sediment quality, remediation procedures and sediment disposal in general. After the treatment, the proportion of these two metals in the first fraction is significantly reduced (Cu less than 2%, Zn 10%) in most of samples. In order to determine the long-term behavior of S/S mixtures, leaching tests were conducted in accordance with semi-dynamic ANS diffusion test for 90 days. The results indicated that clay can effectively immobilize Cu and Zn: the cumulative leached fraction of copper in mixtures with clay was in the range from 0.001% (mixture with 80% clay) to 0.15% (mixture with 10% clay), and the cumulative leached fraction of zinc in the range of 0.06% (mixture with 80% clay) to 0.10% (mixture with 10% clay). The diffusion coefficients, ranging from 1.5×10-12 cm2s-1 to 3.7×10-14 cm2s-1, showed an effective immobilization of both metals which suggests that these metals are practically immobilized in S/S mixtures even if the level of clay is low. From the point of LX values, all S/S mixtures can be used for the controlled utilization, because the leaching indices ranged from 11.8 to 13.4 for both metals. In all clay and sediment mixtures the dominant leaching mechanism is diffusion (slope values of 0.35 to 0.60), which once again confirms the effectiveness of the applied treatment and can be expected that only a very small amount of contaminants would leach into the environment over time. Future research is heading in the direction of troubleshooting the accumulation of used natural adsorbent after treatment, the possibility of permanent disposal, its regeneration or the possibility of its application as construction material

Removal of As(III) and Cr(VI) from aqueous solutions using “green” zero-valent iron nanoparticles produced by oak, mulberry and cherry leaf extracts

Abstract The production of nano zero-valent iron nanoparticles, using the extract from natural products, increased in recent years as it represents green and environmentally friendly method. Synthesis of green zero-valent iron nanoparticles (nZVI) using oak, mulberry and cherry leaf extracts (OL-nZVI, ML-nZVI and CH-nZVI) proved to be a promising approach for As(III) and Cr(VI) removal from aqueous solutions. The oak, mulberry and cherry leaves were chosen because of their high oxidant capacity as an important property for the production of the nZVIs. Also, oak, mulberry and cherry trees are widely distributed and easy to find in Vojvodina, the north province of Serbia. Characterization of produced green nZVI materials confirmed the formation of nanosize zero-valent iron particles within the size of 10–30 nm. Nanoparticles were spherical in shape and represented stable material with minimum agglomeration observed by TEM and SEM morphology measurements. Batch experiments revealed that the adsorption kinetics followed pseudo-second order rate equation. The obtained adsorption isotherm data could be well described by the Freundlich model. In addition, investigated pH effect showed that varying the initial pH value had a great effect on As(III) and Cr(VI) removal. This study indicated that nZVI could be produced by low cost and non toxic method with oak, mulberry and cherry leaf extracts and potentially be used as a new green material for remediation of water matrices contaminated with As(III) and Cr(VI)

Identification of significant pressures and assessment of wastewater discharge on Krivaja River water quality

One of the key stages of the process of preparing management plans for the river basin is the analysis of pressures and impacts, as well as the risk assessment of failing to achieve the environmental objectives. DPSIR framework (Driving Forces-Pressure-State-Impact-Response) was developed by the European Agency for the environmental protection, and makes the conceptual basis for the pressures and impacts analysis, taking into account the complexity of the interactions in the environment and represents the tool for their analysis. Impact assessment of the water body requires some quantitative information to describe the condition of the water body and/or the pressures that act on it. The aim of the study was to determine the effect of wastewater discharge on Krivaja watercourse. Impact assessment is carried out based on data of polluters’ wastewater and monitoring information for water in Krivaja. For each site at which sampling was performed, the specific risk quotients for surface water were calculated, as the ratio of the each pollutant concentration in surface water at the sampling point and environmental quality standards for pollutants, as well as their sum that represents the risk index. In order to have the integrated perceive of processes in the Krivaja River, taking into account cumulative effects from point sources, the concept of total maximum daily load was applied, using which the pollution amount, that can be discharged daily in a water body without degrading his prescribed/required quality, was calculated. Comparison of emitted loads from pollution point sources with maximum allowable ones was performed. Wastewaters of different polluters located on Krivaja are, due to insufficient treatment, very loaded with organic matter and nutrients. Krivaja receives daily 1332 m3 of wastewater, 999 kg COD, 722 kg BOD, 144 kg of nitrogen, 4.3 kg of phosphorus and 627 kg of suspended solids. Of the total wastewater volume, the majority (69%) originates from municipal wastewater, 81% of the total amount of organic matter comes from the industry, while nutrients mostly originate from municipal wastewater. Loading of Krivaja with wastewater is major, uneven and unbalanced. Water quality of Krivaja is unsatisfactory. According to national legislation there is the exceedance of maximum permissible values for Class II for watercourse (good status) for most parameters, in all sampling locations and in both sampling periods. Parameters that exceeded the value for the Class II are dissolved oxygen, organic matter content, suspended solids, nutrients. Water flow in the river is not sufficient to receive the total amount of the pollutant load from point sources. Risk assessment, based on the monitoring results, indicates that the river Krivaja is possibly at risk of failing to meet the required water quality because the most of the values exceeded the limit values. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR37004