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Sediment je nevezan i neučvršćen materijal istaložen na dnu vodenog ekosustava. Sedimenti, kao i zajednice mikrofita (alge i cijanobakterije) u različitim tipovima sedimenata, imaju važnu ulogu u održavanju strukture i funkcije, odnosno procesa koji se odvijaju u vodenim ekosustavima. Mikrofiti u sedimentu pridonose primarnoj proizvodnji, kemijskim transformacijama, zadržavanju hranjivih tvari u sustavu, fizičkoj stabilizaciji podloge te osiguravaju staništa drugim organizmima. Svojte iz skupine Bacillariophyceae (dijatomeje) posebno su dobro zastupljene u sedimentu. Istraživanje dijatomeja u sedimentu na području Kopačkog rita provedeno je na dvije postaje – u Sakadaškom i Kopačkom jezeru u razdoblju plavljenja u veljači i nakon poplave u ožujku 2021. godine. Istraživane postaje su se razlikovale s obzirom na fizikalno-kemijske parametre vode i granulometrijski sastav sedimenta. Dubina vode u Sakadaškom jezeru bila je veća u odnosu na Kopačko jezero i u vrijeme plavljenja dosegla je 720 cm. Tijekom plavljenja u Sakadaškom jezeru zabilježena je visoka koncentracija amonijevih iona (0, 134 mg/L), dok je u Kopačkom jezeru bio visok sadržaj ukupnog dušika (4, 230 mg/L). Nakon poplave, u Sakadaškom jezeru zabilježena je visoka koncentracija ukupnog fosfora od 0, 270 mg/L, dok je u isto vrijeme u Kopačkom jezeru utvrđena vrlo mala koncentracija nitrata (0, 570 mgN/L). Na obje istraživane postaje utvrđena je velika raznolikost dijatomeja u sedimentu. Najzastupljenije su bile svojte rodova Cyclotella, Stephanodiscus, Aulacoseira, Navicula, Nitzschia i Fragilaria. U pjeskovitom sedimentu Sakadaškog jezera dominirale su Aulacoseira granulata u veljači i Stephanodiscus hantzschii u ožujku dok su u pjeskovitom siltu Kopačkog jezera ove vrste bile dominantne tijekom cijelog istraživanja. Rezultati ukazuju da se unatoč razlikama u ekološkim uvjetima i granulometrijskom sastavu sedimenta na obje postaje razvijaju slične zajednice dijatomeja.

Fitoplankton je jedan od pet bioloških elemenata kakvoće vode prema Okvirnoj direktivi o vodama, a njegove su promjene značajan pokazatelj općeg ekološkog stanja vodenih sustava. Dosadašnja istraživanja fitoplanktona u Kopačkom ritu su uglavnom obuhvaćala vegetacijsku sezonu, a nedovoljno je istraženo zimsko razdoblje koje izuzetno značajno može utjecati na razvoj proljetne i ljetne zajednice. Stoga je cilj ovog istraživanja utvrditi strukturu i dinamiku fitoplanktona u Sakadaškom jezeru tijekom zimskog razdoblja. Uzorci su prikupljeni u tjednim intervalima u razdoblju od siječnja do ožujka 2020. godine tijekom stabilnih hidroloških uvjeta. Utvrđeno je 55 svojti koje su svrstane u 20 funkcionalnih grupa fitoplanktona, a najzastupljenije i stalno prisutne su bile vrste iz D, X3, X2 i K grupe koje su karakteristične za plitka jezera. Vrste iz D funkcionalne grupe činile su udio od 4, 86 % do 32, 81 % ukupnog broja jedinki, a najzastupljenija je bila vrsta Stephanodiscus hantzschii, dok je X3 grupa činila udio između 16, 57 % i 26, 33 % s predstavnikom Chrysococcus rufescens. Dominantne vrste iz X2 skupine su bile Plagioselmis nannoplantica i Plagioselmis lacustris, a zastupljenost skupine je varirala između 7, 8 % i 20, 36 %. Aphanocapsa plantonica pojavljivala se tijekom cijelog istraživanja i kao jedini predstavnik K skupine njena je zastupljenost varirala od 3, 57 % do 21, 62 %.

U ovom radu istražena je mogućnost korištenja lignoceluloznog proizvodnog ostatka iz industrije piva, pivskog tropa (PT), kao adsorbensa za uklanjanje sintetskih bojila metilenskog modrila (MM) i kongo crvenila (KC) iz vodenih otopina šaržnim postupkom. Provedena je karakterizacija PT koja je uključivala fizikalno-kemijsku karakterizaciju, određivanje elementnog sastava (CHN-analiza), morfološku karakterizaciju primjenom skenirajuće elektronske mikroskopije (SEM) te analizu funkcijskih skupina infracrvenom spektroskopijom s Fourierovom transformacijom (FT- IR). Po završenoj karakterizaciji istražen je utjecaj različitih čimbenika koji utječu na proces adsorpcije: veličine čestica i koncentracije adsorbensa, vremena adsorpcije i početne koncentracije bojila te pH, temperature i ionske jakosti. Eksperimentalni podatci dobiveni provođenjem šaržnih adsorpcijskih eksperimenata analizirani su primjenom ravnotežnih adsorpcijskih modela (Freundlich i Langmuir) te primjenom odgovarajućih kinetičkih modela (model pseudo- prvog reda i model pseudo-drugog reda) te modela unutarčestične difuzije. Rezultati su pokazali kako se PT može primijeniti kao jeftini adsorbens za uklanjanje MM i KC iz vodenih otopina, pri čemu su veći postotci uklanjanja i veći adsorpcijski kapacitet postignuti za uklanjanje MM. Nadalje, ispitana je mogućnost biološke obrade obojenog pivskog tropa, koji zaostaje nakon uklanjanja bojila, pomoću gljive Trametes versicolor u uvjetima uzgoja na čvrstim nosačima, na osnovu praćenja gubitaka na masi supstrata i promjene boje uzoraka nakon 28 dana uzgoja. Provedeno je i određivanje akutne toksičnosti uzoraka biološki obrađenog obojenog PT, određivanjem imobilizacije slatkovodnog račića D. magna. Dobiveni rezultati upućuju na biotehnološki potencijal gljive T. versicolor za primjenu u procesima biološke obrade obojenih lignoceluloznih materijala, odnosno biorazgradnje sintetskih bojila u uvjetima uzgoja na čvrstim neinertnim nosačima.

Makrofitska vegetacija se razvija u različitim vodenim ekosustavima te predstavlja dobru podlogu za razvoj obraštaja, posebno u plićim vodenim biotopima karakteriziranim manjom dubinom i brzinom vode. Istraživanje mikrofita u obraštajnim zajednicama na različitim tipovima prirodnih podloga: Ceratophyllum demersum L., Lemna spp., Nuphar lutea (L.) Sm., Nymphaea alba L., provedeno je u melioracijskim kanalima na području Baranje na dvije postaje - u blizini farme Eblin i u Dardi, u lipnju i rujnu 2016. godine. Koncentracije hranjivih tvari bile su najviše na drugoj postaji (ukupni dušik: 8, 233 mg/L ; ukupni fosfor: 2, 651 mg/L ; nitrati: 4, 875 mgN/L ; kjeldahl N: 3, 360 mg/L) u lipnju, dok su u rujnu na prvoj postaji zabilježene visoke vrijednosti koncentracije klorofila-a u vodi (4, 613 µg/L) te mase anorganskih i organskih tvari. Raznolikost mikrofita bila je velika na svim tipovima istraživanih podloga (ukupno 201 svojta). Najveći broj svojti (100) zabilježen je na vrsti C. demersum u lipnju na prvoj postaji, a najmanji (42) u rujnu na Lemna spp. na drugoj postaji. U oba istraživana razdoblja na oba lokaliteta i na svim tipovima podloga u obraštaju najveći je broj svojti pripadao skupinama Bacillariophyceae i Chlorophyta, ali su brojem jedinki uz Bacillariophyceae (Fragilaria construens, Cocconeis placentula) dominirale svojte Heteroleibleinia sp. i Tolypothrix sp. iz skupine Cyanobacteria. Rezultati ukazuju da se zajednica mikrofita u obraštaju u eutrofnim sustavima razvija ovisno o ekološkim uvjetima unutar vodenog biotopa, a posebice ovisi o svojstvima same podloge.

Macrophytic vegetation present in various aquatic ecosystems provide a good substrate for the development of epiphytic algae and cyanobacteria. A macrophyte Ceratophyllum demersum is particularly well developed and has great coverage in channels characterised by low water velocity. The research on microphyte diversity and abundance on C. demersum was conducted in three drainage channels in Baranja (Eastern Croatia) in September 2016. Different values of physico- chemical water properties were found in investigated biotopes. Higher concentrations of oxygen (9.72 mg/L), total phosphorus (0.88 mg/L) and higher conductivity were found in the shallowest channel in Jagodnjak, while two other channels (near Eblin and Darda) had a higher concentration of nitrogen compounds. The highest content of chlorophyll a in water (41.61 μg/L) and epiphyton (Chl-a: 509.19 ± 67.88 µg/gDW), as well as high microphyte diversity (94) and abundance (555 672, 05 x 10 3 ± 49 261, 11 x 10 3 cell/gDW) was found in the channel near Eblin. Cyanobacteria Heteroleibleinia ucrainica was the most abundant at all localities accompanied by Tolypothrix sp. in the channel near Darda. An invasive and potentially toxic cyanobacteria Cylindrospermopsis raciborskii was found near Eblin. The results indicate that despite differences in the physico-chemical environment and channel hydro-morphology, the substrate type is one of the most important factors conditioning epiphyton development and structure in eutrophic aquatic biotopes.

The Drava is 725 km long river located in central Europe, with basin size of 40 150 km². It is a tributary of Danube, its source is in Italy and flows through Italy, Austria, Slovenia, Croatia and Hungary, and flows into Danube 2.5 km northwest from Aljmaš (Croatia). The Drava passes through several large settlements in Austria, Slovenia, Croatia and Hungary, and is a collector of wastewater from these settlements (areas with intensive industrial agricultural production). Since wastewaters are usually loaded with nutrients, the aim of this study was to collect and analyse concentration of nitrogen and phosphorus compounds and BOD5 and COD (whose concentration in water must comply with the permissible limit value in order to avoid nutrient overload of environment and eutrophication) in surface waters. Samples were taken twice a month over the period of ten years (year 2004 and 2013), at two locations – upstream from Osijek and in Donji Miholjac. Obtained results show that during analysed period concentration of total nitrogen was in the range of 0.325–4.59 mg/L (Osijek) and 0.74– 2.763 mg/L (Donji Miholjac), concentration of nitrites was 0.001–0.03 mg/L (Osijek) and 0.001– 0.078 mg/L (Donji Miholjac), and concentration of nitrates was 0.41¬–4.068 mg/L (Osijek) and 0.50¬–2.43 mg/L (Donji Miholjac). Concentration of orthophosphates was in the range of 0.005– 1.06 mg/L (Osijek) and 0.002–0.07 mg/L (Donji Miholjac), and total phosphorus was in the range of 0.030–2.15 mg/L (Osijek) and 0.018–0.406 mg/L (Donji Miholjac). Biological oxygen demand (BOD5) was in the range of 0.1–6.8 mgO2/L (Osijek) and 0.4–3.9 mgO2/L (Donji Miholjac). Chemical oxygen demand (COD-Mn) was in the range of 1.5–6.9 mgO2/L (Osijek) and 1.6–9.8 mgO2/L (Donji Miholjac). COD-Cr was in the range of 3.5–74.9 mgO2/L (Osijek) and 3–27.1 mgO2/L (Donji Miholjac). According to current regulations in Croatia, surface water quality of Drava River with regard to physico-chemical parameters can be characterized as good. Further continuous monitoring of water quality is necessary in order to improve reliability of water quality categorization, for which purpose specific polluting particulate matter should also be taken into consideration.

U ovom radu istražena je mogućnost upotrebe micelijskih peleta gljive bijelog truljenja Trametes versicolor CCBAS AG 613 s ciljem uklanjanja sintetskog bojila malahitnog zelenila iz vodene otopine. Istraživan je utjecaj početne koncentracije biomase, koncentracije malahitnog zelenila i dodatka glukoze u otopinu bojila na postotak uklanjanja bojila. U gotovo svim provedenim pokusima postotak uklanjanja bojila nakon 24 h iznosio je preko 80 %. Povećanjem početne koncentracije biomase došlo je do povećanja postotka uklanjanja bojila; dok je povećanje koncentracije bojila, neovisno o početnoj koncentraciji biomase, imalo suprotan učinak. Dodatak glukoze u vodenu otopinu bojila rezultirao je manjim postotkom uklanjanja bojila. Nadalje, istražena je mogućnost ponovnog korištenja peleta u drugom ciklusu. U ponovljenom testu peleti su zadržali sposobnost uklanjanja bojila iz vodene otopine malahitnog zelenila, ali u nešto manjem postotku nego prilikom prvog korištenja. Ovi preliminarni rezultati upućuju na mogućnost korištenja micelijskih peleta T. versicolor CCBAS AG613 za biološku obradu otpadnih voda obojenih malahitnim zelenilom. The aim of this study was to investigate the malachite green removal (decolourisation) ability of white rot fungus Trametes versicolor CCBAS AG613 mycelial pellets. The effect of initial biomass concentration, malachite green concentration and glucose addition on dye percentage removal was investigated. The dye percentage removal of more than 80% was achieved after 24 h in almost all runs. An increase in the initial biomass concentration positively affected the removal, resulting in higher dye percentage removal. However, the increase in dye concentration had the opposite effect. The addition of glucose to the dye solution resulted in slightly lower dye percentage removal. Furthermore, the longevity of pellets’ decolourisation activity was tested in repeated-batch mode. When used in repeated-batch mode, pellets still exhibited the malachite green decolourisation activity but to a slightly lower extent. These preliminary results indicate that T. versicolor CCBAS AG613 mycelial pellets could be effectively used for bioremediation of malachite green coloured wastewaters.

Pollution of the environment is one of the major problems of today. Main causes of pollution are anthropogenic and can be classified in three groups: waste water (industrial and agricultural, domestic, communal waste waters), atmospheric pollutants distributed to soil and water by precipitation or sedimentation (industrial emissions, fossil fuel combustion emissions, traffic emissions, emissions from landfills and waste incineration), and solid waste (communal, industrial, agricultural). The faith of pollutants, once they are deposited in the environment, depends on various physical, chemical and biological factors. Inorganic pollutants, unlike organic pollutants, cannot be degraded and are accumulated in the soil and sediment, what further complicates the problem. From the soil, they can enter the plants and participate in the food chain, or the can get into the ground waters, and eventually surface waters, where they pose a serious health threat. Hence, in order to improve current state of the environment and to stop further pollution nowadays different measures are applied (remediation). Modern day remediation methods can be generally grouped into four groups (biological, chemical, physical, thermal), but are often combined. Their main aims are to reduce the pollutant concentration at an acceptable level, isolate pollution, and reduce pollutant bioavailability. The choice of the technology depends on several factors, such as the type of the pollution, soil type and purpose, spatial component of the pollution (surface, volume, location, proximity of surface or ground water), and the time component of the pollution (time frame of exposure to the pollutant). Great significance have remediation technologies that allow preservation original form of soil, such as phytoremediation or electrochemical remediation. The aim of this study was to give an overview and analysis of advantages and disadvantages of advanced remediation methods for soil and water purification.

Cilj ovog rada bio je istražiti mogućnost biološke obrade otpadnog lignoceluloznog materijala pivskog tropa obojenog sintetskim bojilima metilenskim modrilom i kongo crvenilom pomoću gljive Trametes versicolor TV8 u uvjetima uzgoja na čvrstim nosačima. T. versicolor TV8 dobro je rasla na obojenom pivskom tropu, što je, osim vidljivog bijelog micelija, potvrđeno gubitkom mase supstrata te povećanjem udjela vlage i proteinskog dušika nakon 21 dana fermentacije, u usporedbi s abiotičkom kontrolom. Promjene parametara boje (određivani kromametrijski) obojenih uzoraka tropa dobivenih na kraju fermentacije u odnosu na abiotičku kontrolu, upućuju na promjenu nijansi analiziranih boja tj. razgradnju gljivom T, versicolor TV8. Dobiveni rezultati upućuju na biotehnološki potencijal gljive T. versicolor TV8 za primjenu u procesima biološke obrade obojenih lignoceluloznih materijala, odnosno biorazgradnje sintetskih bojila u uvjetima uzgoja na čvrstim neinertnim nosačima.

Nitrogen is one of the most abundant elements in nature, present in (in)organic forms of which most dominant ones are elementary nitrogen, nitrate, nitrite and ammonia, which are interconnected by the nitrogen cycle. Which of the nitrogen compounds will be present in the nature depends on chemical, physical and biological conditions, while agriculture is one of their main sources. Water pollution caused by agriculture is usually a result of over fertilisation, where the excess nitrogen is flushed by leachate into the underground and surface waters, polluting them and reducing sources of drinking water. Due to weak (or none) binding of nitrates to the soil particles, nitrates are nitrogen compounds that are most intensely flushed. Processes that lead to nutrient accumulation in surface waters are surface run-off, drainage water, soil erosion, and even direct input. The concentration of nutrients in the water depends on several factors, such as the type, amount, way and time of fertilisation ; soil type ; amount of precipitations ; type of crops, etc. The aim of this study was to give an overview of sources of nitrogen compounds, processes in which they take part, and their impact on the health and the environment. Though nitrogen is an important nutrient for plant growth and development, its excess has a negative impact on the environment and leads to eutrophication of the surface waters, especially pronounced in the lowland European rivers. This transformation of the aquatic ecosystem refers to the accumulation of nutrients which leads to the accelerated plant growth, eventual disruption of the equilibrium and other adverse changes of the aquatic ecosystem. Finally, ecosystem biodiversity and water quality, as well as its use, are drastically reduced, defining anthropogenic eutrophication one of the major problems of today. Also, increased nitrates concentration has a negative effect on health. Though nitrates toxicity is low, and nitrates are readily eliminated, about 5% of ingested nitrates is metabolised in nitrites, which are about 10 times more toxic than nitrates. Nitrites oxidise haemoglobin iron to methaemoglobin, a compound that cannot transfer oxygen thus causes cyanosis and a condition called methaemoglobinemia. Increased concentration of nitrates in drinking water is linked with the development of various illnesses, such as respiratory illnesses, reproductive problems and some types of cancer.

Mur River (Croatian: Mura) is a 464 km long river located in Međimurje region in Croatia, and it is Croatia’s most northern river. Originating in Austria, it flows through Slovenia and Hungary, continues its flow in Croatia where it flows into the Drava River. Mur River is one of the last significantly preserved lowland rivers, thus the aim of our study was to analyse the Mur River water quality to determine whether water quality has changed over the time and how. To that purpose, concentration of nitrogen and phosphorus compounds in the Mur River surface waters was analysed. Samples were taken at location Goričan, once to twice a month over the period of ten years (2004–2013). During analysed period concentration of total nitrogen was within the range of 0.48–3.771 mg/L, concentration of nitrites was 0.001–0.175 mg/L, while concentration of nitrates was 0.75–3.06 mg/L. Concentration of orthophosphates was within the range of 0.005–0.141 mg/L, and concentration of total phosphorus was 0.025–1.01 mg/L. The highest concentration of total nitrogen was measured in water samples collected in March of 2006, nitrates in December of 2008, while the highest concentration of nitrites was measured December of 2012. The highest concentration of total phosphorus was measured in May of 2006, and orthophosphates in January of 2007. Analysed nutrients show a decrease in value during 2013, with lowest measured value of nitrites of 0.007 mg/L, nitrates 0.97 mg/L, total nitrogen 0.48 mg/L, orthophosphates 0.015 mg/L, and total nitrogen of 0.025 mg/L.

Pollution of the environment has become one of significant problems of today, especially air pollution due to the negative impact of air pollutants on health of people, animals and plants. Several test have been developed in order to examine and assess the impact of air pollution on the quality of life, such as Tradescantia micronucleus test (Trad-MCN) which uses plants and clones of the Tradescantia genus as model organisms. Trad-MCN test has been developed to study the effect of the gaseous mutagens, and nowadays is one of the most often used plant toxicity tests in studies of genotoxic impact of various mutagenic substances related to soil pollution, heavy metals, traffic gas emission, waste water, petrochemical gas emission, smog, etc. The aim of our study was to give an overview of the advantages and disadvantages of Trad-MCN test, and to determine whether the test should be further improved. Data base composed of results of up to now conducted studies with Trad-MCN test allows further research of the degree of genotoxicity in specific environmental situations (studies of combined effect of various specific substances), comparison of obtained results, and design of further research and strategic defence against the negative impact of pollutants. Research on heavy metals show strong positive reaction of potential carcinogenic metals with Trad-MCN test, while non-carcinogenic metals don’t show such reaction. Results of additional research indicate that the test can be used in monitoring of the effect of heavy metals, pesticides, radionuclides, and other substances. The limitation of the test is in its inapplicability in the studies of specific substances for which cooperation of several enzymes is necessary, thus in future research a combination of plant toxicity tests with other available tests will be necessary. Such approach will result in higher quality of the ecological studies, and will give a more complete characterisation of the environment condition.

The 7th International Scientific and Professional Conference Water for all is organized to honour the World Water Day by the Josip Juraj Strossmayer University of Osijek, European Hygienic Engineering & Design Group (EHEDG), Danube Parks, Croatian Food Agency, Croatian Water, Faculty of Food Technology Osijek, Faculty of Agriculture in Osijek, Faculty of Civil Engineering Osijek, Josip Juraj Strossmayer University of Osijek Department of Biology, Josip Juraj Strossmayer University of Osijek Department of Chemistry, Nature Park “Kopački rit”, Osijek- Baranja County, Public Health Institute of the Osijek- Baranja County and „Vodovod-Osijek“ -water supply company in Osijek. The topic of World Water Day 2017 was "Wastewater" emphasizing the importance and influence of wastewater treatments on global environment. The international scientific and professional conference Water for all is a gathering of scientists and experts in the field of water management, including chemists, biologists, civil and agriculture engineers, with a goal to remind people about the significance of fresh water and to promote an interdisciplinary approach and sustainability for fresh water resource management. The Conference has been held since 2011. About 300 scientists and engineers submitted 95 abstracts to the 7th International Scientific and Professional Conference Water for all, out of which 33 was presented orally and 62 as posters. 47 full papers were accepted by the Scientific Committee. 38 full papers became the part of the this Proceedings while 9 papers were accepted for publication in Croatian Journal of Food Science and Technology and Electronic Journal of the Faculty of Civil Engineering Osijek - e-GFOS.

Microphytes (algae and cyanobacteria) in the sediment of aquatic biotopes greatly influence its stabilization capacity, regulate nutrient cycling (benthic-pelagic) and primary production. Moreover, they represent one of the main quality elements for the assessment of the ecological status of aquatic ecosystems according to the European regulation. The research on sediment-associated microphytes was conducted in the Danube River and Lake Sakadaš in autumn of 2016. Due to the low Danube water level (0, 71-2, 54 m) different ecological conditions were established in the two investigated biotopes. Higher concentrations of nutrients (total nitrogen: 3, 0731 mg/L ; total phosphorus: 0, 4697 mg/L ; nitrites: 0, 0107 mgN/L) and surface water chlorophyll concentrations, as well as a greater amount of sediment inorganic and organic matter were found in Lake Sakadaš. On the contrary, higher water nitrate concentration (1, 372 mgN/L) and higher sediment chlorophyll content (Chl-as: 9, 64±1, 34 µg/cm2 ; Chl-bs: 2, 76±0, 52 µg/cm2 ; Chl-cs: 3, 69±1, 59 µg/cm2) were recorded in the Danube. The research found high microphyte diversity in the sediment of both the river (63) and its floodplain lake (99). Two representatives of cyanobacteria, an invasive species Cylindrospermopsis raciborskii and Heteroleibleinia ucrainica, as well as green alga Monoraphidium contortum and diatom Navicula cryptocephala were the most common microphytes at both sites. The established microphyte community structure suggests that both aquatic ecosystems have characteristics of eutrophic waters.

In freshwater environments, zooplankton influences the functioning of an ecosystem through its species composition and biomass which affects the structure of other food web components. By using a zooplankton functional groups viewpoint, species can be arranged into classes with distinct ecological roles. The aim of the study was to evaluate the change in zooplankton taxonomical and functional feeding groups among different habitat types, following season and hydro regime replacement. Six sampling sites were chosen: two river stations (Danube, Site 1 ; Drava, Site 2), one floodplain lake (Lake Sakadaš, Site 3), and three channels placed close to the farm areas (Sites 4-6). Samples were collected on two occasions in 2016: in June during flood and September in low water period. A total of 73 zooplankton species were recorded (53 Rotifera, 14 Cladocera and 6 Copepoda). Among measured environmental variables, water depth and conductivity values varied significantly among sites, while transparency values and concentrations of total nitrogen and total phosphorous oscillated between seasons. All zooplankton taxonomical groups differed significantly among sites, while functional classification revealed spatial oscillation in microphagous species. During low water period cladocerans and copepods strongly correlated with dinophytes and cryptophytes, with the dominance of small-bodied microcrustaceans (Ceriodaphnia sp., Thermocyclops sp.) known to prefer these algae in their diets. Following flooding condition, rotifers correlated with several phytoplankton groups, especially chrysophytes, chlorophytes and xanthophytes. At sites 3 and 5 significant proportion of cyanobacteria during September influenced the development of bacteria‐detritus suspension and minute algae feeding zooplankton species (Anuraeopsis fissa, Brachionus angularis) with occasional occurrence of raptorials. Algivorous zooplankton species, especially those feeding on algae ranging in size from 20-50 µm, like Synchaeta genera, prevailed at sites where chlorophytes, diatoms and cryptophytes were abundant. The raptorial way of feeding characterised high-flow environments, especially during low water period, while microfilter-feeders marked channel environments. The results of our study point to the significant spatial oscillation of zooplankton functional groups and indicate proper diagnostics of the applied approach in describing the lower trophic levels, in all types of studied environments.

Synthetic dyes, widely used in many industries, are a heterogeneous group comprised of structurally very diverse compounds. Coloured industrial effluents represent the most common sources of water pollution with dyes. The most often used method for the removal of dyes from industrial effluents is adsorption, which is efficient but costly method due to the price of conventional adsorbents. Therefore, different lignocellulosic waste materials have been examined, as possible adsorbents. Dye-loaded lignocellulosic materials after adsorption process has to be adequately disposed of, so the treatment through solid state fermentation (SSF) by white-rot fungi is proposed in order to degrade both the material and dye. To measure the extent of the Congo Red (CR) dye degraded from biosorbent for future analysis of samples after SSF, individual solvents were used to extract CR adsorbed onto brewers’ spent grain (BSG). Nonpolar solvents (dichloromethane, benzene, chloroform, toluene, and xylene), polar aprotic solvents (ethyl acetate, acetone, tetrahydrofuran, dimethylformamide, acetonitrile, dimethyl sulfoxide), and polar protic solvents (water, ethanol, methanol, and amyl alcohol) were used. A two-component solvent system and three- component solvent system were also tested. Taking into account the new solvents introduced in the last decades as an alternative to traditional organic solvents, deep eutectic solvents (DESs) were also evaluated in the present study. The effect of molar ratio choline chloride and different hydrogen bond donor in DESs on extraction efficiency of CR from dye-adsorbed BSG was investigated. Out of the tested polar protic solvents, methanol showed the highest extraction efficiency of CR from dye-loaded BSG. When polar aprotic solvents were used, the highest extraction efficiency was achieved using acetonitrile. Compared to individual solvents, the extraction efficiency was significantly increased when multicomponent solvents were used. DESs were less efficient than both the polar protic and polar aprotic solvents.

U ovom radu istražena je mogućnost upotrebe micelijskih peleta gljive bijelog truljenja Trametes versicolor CCBAS AG 613 s ciljem uklanjanja sintetskog bojila malahitnog zelenila iz vodene otopine. Istraživan je utjecaj početne koncentracije biomase, koncentracije malahitnog zelenila i dodatka glukoze u otopinu bojila na postotak uklanjanja bojila. U gotovo svim provedenim pokusima postotak uklanjanja bojila nakon 24 h iznosio je preko 80 %. Povećanjem početne koncentracije biomase došlo je do povećanja postotka uklanjanja bojila ; dok je povećanje koncentracije bojila, neovisno o početnoj koncentraciji biomase, imalo suprotan učinak. Dodatak glukoze u vodenu otopinu bojila rezultirao je manjim postotkom uklanjanja bojila. Nadalje, istražena je mogućnost ponovnog korištenja peleta u drugom ciklusu. U ponovljenom testu peleti su zadržali sposobnost uklanjanja bojila iz vodene otopine malahitnog zelenila, ali u nešto manjem postotku nego prilikom prvog korištenja. Ovi preliminarni rezultati upućuju na mogućnost korištenja micelijskih peleta T. versicolor CCBAS AG613 za biološku obradu otpadnih voda obojenih malahitnim zelenilom.

Adsorption is the method most often used for the removal of dyes from industrial effluents. However, due to the high-cost of conventional adsorbents, a wide range of lignocellulosic waste materials are being extensively investigated as a possible novel adsorbents. Many of them proved to be very effective. Dye-loaded lignocellulosic material cannot be directly discarded to the environment, so one of the alternatives is to ferment it using fungi that are capable of degrading the dye. For the purpose of future analyses of fermented dye-loaded lignocellulosic material, i.e. the quantification of the dye degradation extent, a series of organic solvents were used to extract the methylene blue (MB) adsorbed onto brewers’ spent grain (BSG). Both unfermented and fermented (solid-state fermentation using T. versicolor) dye-adsorbed BSG samples were tested. The individual solvents used in this study included nonpolar slovents (benzene, toluene, chloroform, dichloromethane and xylene), polar aprotic solvents (tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, acetonitrile, dimethyl sulfoxide), and polar protic solvents (ethanol, methanol, amyl alcohol and water). Furthermore, a two-component solvent system (methanol : water 1 : 1) and three-component solvent system (methanol : chloroform : water 1 : 1 : 1) were also used. To stress the importance of the principles of green chemistry, ultrasonic-assisted extraction of MB from BSG with deep eutectic solvents (DES), choline chloride/hydrogen bond donor (ChCl/HBD) was also explored. The results showed that the highest desorption of MB from BSG was achieved using polar protic solvents, out of which methanol was the best. The lowest desorption was achieved using non-polar solvents. The results of the MB extraction from BSG using deep eutectic solvents indicated that some of the tested eutectic solvents could be used as an “green” alternative to organic solvents. However, they were far less efficient than the polar protic solvents.

Proceedings contains articles presented at Conference divided into sections: open lecture (1), chemical analysis and synthesis (3), chemical and biochemical engineering (8), food technology and biotechnology (8), medical chemistry and pharmacy (3), environmental protection (11) and meeting of young chemists (2).

Polyphenols are micronutrients with various health promoting effects, and as such have an important role in the prevention of degenerative diseases, for instance cancer and cardiovascular diseases. To this date, there are over 8 000 identified polyphenols found in plants and plant products, such as fruit, tea, coffee, etc. Polyphenol content in food has been determined by various analytical methods (over several hundred scientific publications) and compiled in the Phenol-Explorer database (more than 35 000 content values for 500 different polyphenols in over 400 foods). Our aim was to evaluate the content of polyphenols in selected foods (fruit and derived products) to identify the richest sources of polyphenols among them, in order to determine which of them contribute significantly to the polyphenol intake. Total polyphenol content was calculated as the sum of the contents of all individual polyphenols (determined by chromatography) and was compared with the content of antioxidants, which was extracted from the same database. Based on data obtained by comprehensive queries in the Phenol-Explorer database, the ranking of the polyphenol content in selected foods was made. Our results indicate that polyphenol content in selected food items varies from 3 448 mg per 100 g in cocoa powder to 10 mg per 100 ml in wine.

U ovom radu istražena je mogućnost upotrebe micelijskih peleta gljive bijelog truljenja Trametes versicolor CCBAS AG 613 s ciljem uklanjanja sintetskog bojila malahitnog zelenila iz vodene otopine. Istraživan je utjecaj početne koncentracije biomase, koncentracije malahitnog zelenila i dodatka glukoze u otopinu bojila na postotak uklanjanja bojila. U gotovo svim provedenim pokusima postotak uklanjanja bojila nakon 24 h iznosio je preko 80%. Povećanjem početne koncentracije biomase došlo je do povećanja postotka uklanjanja bojila ; dok je povećanje koncentracije bojila, neovisno o početnoj koncentraciji biomase, imalo suprotan učinak. Dodatak glukoze u vodenu otopinu bojila rezultirao je manjim postotkom uklanjanja bojila. Nadalje, istražena je mogućnost ponovnog korištenja peleta u drugom ciklusu testa obezbojenja. U ponovljenom testu obezbojenja peleti su zadržali sposobnost obezbojenja vodene otopine malahitnog zelenila, ali u nešto manjem postotku nego prilikom prvog korištenja. Ovi preliminarni rezultati upućuju na mogućnost korištenja micelijskih peleta T. versicolor CCBAS AG613 za biološku obradu otpadnih voda obojenih malahitnim zelenilom.

U ovom radu istražena je sposobnost obezbojenja sintetskih bojila (malahitno zelenilo MZ, kristal violet KV, fuksin F i metilensko modrilo MM) pomoću četiri vrste gljiva bijelog truljenja: P. chrysosporium CCBAS 570, T. versicolor CCBAS AG613, T. versicolor TV6 i C. subvermispora. Gljive su uzgajane pri 27 ⁰C 9 (10) dana na agarnim pločama s dodatkom bojila u koncentracijama 50, 100 i 150 mg L\(^{-1}\). Zona rasta kolonija te zona obezbojenja (promjene boje) mjerene su (u dva međusobno okomita smjera) svaka 3 dana. MZ je snažno inhibiralo rast svih vrsta, ali su sve pokazale dobru sposobnost obezbojenja ovog bojila, što je vidljivo iz velikog indeksa obezbojenja (promjer obezbojenja/promjer kolonije) u rasponu od 2,42 do 6,04. Sposobnost djelomičnog obezbojenja KV pokazale su sve vrste gljiva, pri čemu je rast vrsta P. chrysosporium i C. subvermispora bio snažno inhibiran ovim bojilom. F je inhibirao rast odabranih gljiva samo tijekom prvih dana uzgoja. Sposobnost obezbojenja F pokazale su sve vrste, ali indeks obezbojenja nije bio velik (0,24 – 1). Inhibicija rasta ovim bojilom primijećena je samo u prvim danima uzgoja. MM nije inhibiralo rast gljiva, ali je djelomičnu sposobnost obezbojenja ovog bojila pokazala jedino vrsta T. versicolor TV6. Utvrđeno je kako primijenjene koncentracije bojila u podlozi statistički značajno utječu na rast kolonija gljiva, ali nije utvrđena statistički značajna razlika u sposobnosti obezbojenja. Four white rot fungi P. chrysosporium CCBAS 570, T. versicolor CCBAS AG613, T. versicolor TV6 and C. subvermispora were tested for their ability to decolourise synthetic dyes (Malachite Green MG, Crystal Violet CV, Fuchsine F and Methylene Blue MB). Fungal species were cultivated at 27 °C for 9 (10) days on Potato dextrose agar plates containing dyes at final concentrations of 50, 100 and 150 mg L\(^{-1}\). The colony radial growth and the decolourisation zone (in two perpendicular directions) were measured every three days. Although all fungal strains were strongly inhibited by MG, high decolourisation index (decolourisation diameter/mycelial diameter) ranging from 2.42 to 6.04 for all tested species indicated very good decolourisation ability. CV strongly inhibited the growth of all fungi except P. chrysosporium. However, all species partially decolourised CV. F was also decolourised by all strains but the decrease in decolourisation efficiency was observed (decolourisation index ranging from 0.24 to 1). Inhibitory effect of F to fungal growth was observed only during the first cultivation days. Only T. versicolor TV6 partially decolourised MB, even though this dye did not inhibit the mycelial growth of the tested fungal strains. The influence of agar plate dye concentration on fungal growth was statistically significant, while no statistical significance was observed regarding the decolourisation ability.

Epidemiological studies have shown that polyphenols, biologically active compounds present in herbs, as well as in fruit and vegetables, have various health beneficial effects. However, due to the fact that polyphenols generally have low bioavailability (nM range), their biological activity can be ascribed to their colon catabolites, which are present in the circulation in higher concentrations (μM range). The majority of structurally complex polyphenols undergo colon metabolism, and produce a common set of simple phenols and hydrobenzoic acids, which are also widely present in the plant kingdom. The antioxidant activity of selected polyphenols (apigenin, luteolin, and quercetin) and their catabolites (caffeic acid, hydrocaffeic acid, protocatechuic acid, homoprotocatechuic acid, 4-methylcatechol, catechol) was studied in silico using the DFT approach. The geometry optimizations and frequency calculations were carried out using the M05-2X functional and the 6-311++G(d, p) basis set, in conjunction with the SMD continuum solvation model. Two radical scavenging mechanisms were studied, the hydrogen atom transfer (HAT) and the sequential proton loss electron transfer (SPLET). The obtained results indicate the selected polyphenols, originally present in herbs (angelica, celery, chives, coriander, common verbena, dill, fennel, fenugreek, oregano, marjoram, rosemary, anise, sage, lemon balm, wild marjoram, spearmint, tarragon, to name a few), and their catabolites as excellent free radical scavengers, with the average BDE values of 336.39 kJ/mol (BDE1) and 310.45 kJ/mol (BDE2), and the average ETE values of 321.75 kJ/mol (ETE1) and 316.31 kJ/mol (ETE2). The Gibbs free energy change for the HAT/SPLET mechanism of the studied compounds with a particular free radical was also calculated. The obtained results indicate these compounds as efficient deactivators of various free radicals, with the average ΔrGBDE1 for scavenging of the HOO∙ radical of -22.26 kJ/mol and the ΔrGBDE2 of -48.54 kJ/mol, and the averageΔrGPA1 of -34.39 kJ/mol and the ΔrGPA2 of -63.55 kJ/mol.

The Karašica-Vučica River catchment area is located in eastern Croatia in the Pannonian Plain, and extends from Papuk and Krndija mountains in the south to Drava River in the north, and from the Municipality of Petrijevci in the east to the town of Slatina and the Municipality of Voćin in the west. It is located in the territory of Osijek-Baranja and Virovitica-Podravina Counties, which is a fertile agricultural and forested land with a total area of 2, 352.63 km2 (1, 419.87 km2 of which is agricultural land). The aim of this study was to collect and analyse data on concentration of heavy metals: copper, zinc, cadmium, chromium, nickel, lead, mercury, arsenic, manganese and iron, in Karašica-Vučica River surface waters. Samples were taken in the period 2010–2015 and cover several locations: Karašica Črnkovci, Karašica downstream from Valpovo, Vučica Marijančaci, Vučica Petrijevci and Vučica Beničanci. Mean annual value of heavy metals concentration was within legally defined boundaries, except in the year 2011 at location Črnkovci, where concentration of arsenic in surface water was elevated and amounted to 12.134 µg/L. Analysis of collected data regarding surface water of Karašica River points out to a slight increase in value of concentration of analysed metals, which are still within legally defined boundaries. One observed exception was concentration of arsenic, which by the year 2015 decreased to the value of 8.26 µg/L. Analysis of data regarding concentration of heavy metals in Vučica River surface water points out to a decrease in value, with highest observed concentrations measured at locations Beničanci and Marjančaci, and lowest at location Petrijevci. The exception was concentration of arsenic for which in 2012 higher value was measured at location Petrijevci (7.9 µg/L, in compare to 3.5 µg/L, measured at location Marjančaci, and 3.6 µg/L measured at location Beničanci).

Selenium is a widely distributed element generally found in low concentrations in the environment. Anthropogenic activities contribute to elevated content of selenium in aquatic ecosystems, while its accumulation, especially in floodplain systems, is under-investigated. The physico-chemical water properties, selenium concentration in water, sediment and biota as well as the composition and abundance of phytoplankton and periphytic algae were investigated in July 2016, in the Danube River, Sakadaš Lake and the channel located near the farm Eblin (Kopački Rit floodplain). In the conditions of high water level more comparable concentrations of nutrients were found between river and lake water (total nitrogen: 7.57 - 9.31 mg/L, total phosphorus: 2.77 to 2.82 mg/L, nitrates: 5.87 - 6.77 mg N/L). Low selenium content in water and sediment was found in all localities, with the highest concentration in the river sediment (0.256 ± 0.012 mg/kg). Higher selenium concentrations were found in plankton samples (Danube River: 0.385 ± 0.013 mg/kg, Sakadaš Lake: 0.332 ± 0.098 mg/kg). At all localities the diatoms dominated in phytoplankton, while cryptophytes, green algae and cyanobacteria were abundant in the lake and the channel. Selenium concentration in metaphyton, macrophytes (white water-lily, yellow pond-lily, fringed water-lily, common frogbit, common reed, cattail) and periphyton on different substrates varied considerably, while the lowest value was recorded in cattail leaves (0.014 ± 0.004 mg/kg), and the highest in metaphyton (0.277 ± 0.012 mg/kg). The variations in selenium content in different components of aquatic systems indicate the importance of investigating the distribution of selenium in water biotopes.

Gaboška Vučica is a 16.118 km long tributary of Vuka River (the Markušica municipality, Vukovar- Srijem County). The part of the Vuka River between the border with Osjek-Baranja County and its confluence into the Danube River (in Vukovar) has two tributaries: the Bobota Canal, which merges with the Vuka River in Vukovar, and Gaboška Vučica, which collects water from Nuštarska Greda and Krndija mountain. Gaboška Vučica is a collector of wastewater from municipality of Markušica (an area with intensive agricultural production) and since wastewaters are usually loaded with nutrients the aim of this study was to collect and analyse concentration of nitrogen and phosphorus compounds (whose concentration in water must comply with the permissible limit values in order to avoid nutrient overload of environment and eutrophication) in surface water of Gaboška Vučica. Samples were taken once a month during 2014 and 2015. Obtained results show that during analysed period concentration of total nitrogen ranged 0.405–6.43 mg/L, concentration of nitrites 0.007–0.02 mg/L, and concentration of nitrates 0.13¬–6.1 mg/L. Concentration of orthophosphates and total phosphorus ranged 0.016–0.15 mg/L. The highest concentration of total nitrogen and nitrites was measured in the sample collected in March of 2015, while samples collected in summer months of the same year had the lowest concentration of these nutrients. The highest concentration of nitrites was measured in sample collected in October of 2014, and the lowest in July of the same year, when also the highest concentration of total phosphorus and orthophosphates was measured. Concentration of total phosphorus and orthophosphates decreases during 2015, with lowest values measured in the spring months of that year (April, May). According to current regulations in Croatia, surface water quality of Gaboška Vučica with regard to chemical parameters can be characterized as good. Further continuous monitoring of water quality is necessary in order to improve reliability of water quality categorization, for which purpose specific polluting particulate matter should also be taken into consideration.

Karašica River (tributary of the Danube) is a 81 km long river located in Hungary and Croatia, with catchment area of 910 km2. Originating in Hungary (east of Pecs), it flows towards the south. It crosses the Hungarian-Croatian border near the village of Luč (Municipality of Petlovac, Osijek-Baranja County) and continues its flow in an eastward direction, until it flows into the Danube River near Batina. Industrial pollution decreased notably throughout Croatia since 1991, so the aim of our study was to analyse Karašica River water quality to determine whether water quality has changed because of the pollution. For this purpose, concentration of nitrogen and phosphorus compounds in Karašica River surface waters was analysed. Samples were taken once a month in the period 2010–2015. During analysed period, concentration of total nitrogen ranged 1.434–5.683 mg/L, concentration of nitrites 0.007–0.126 mg/L, while concentration of nitrates ranged 0.114–5.42 mg/L. Concentration of orthophosphates ranged 0.018–0.299 mg/L, and concentration of total phosphorus ranged 0.05– 0.421 mg/L. The highest concentration of analysed nutrients was measured in the water samples collected at location Batina – total nitrogen (February of 2015), total phosphorus (October of 2014) and orthophosphates (May of 2015). The highest concentration of nitrites was measured in a water sample from location Branjin Vrh, in May of 2012. Analysed nutrients show a decrease in value during 2015, with lowest measured value of nitrites of 0.007 mg/L, nitrates 0.7 mg/L, total nitrogen 1.96 mg/L, orthophosphates 0.01 mg/L, and total phosphorus of 0.05 mg/L. According to current regulations in Croatia, based on chemical parameters surface water quality of Karašica River can be characterized as moderate. Further continuous monitoring of water quality is necessary in order to improve reliability of water quality categorization.

Planktonic, epiphytic and benthic cyanobacteria were investigated in June and September 2016 in the floodplain Lake Sakadaš (Kopački Rit Nature Park, Croatia). The hydrological regime strongly influenced the physico-chemical environment of the lake, as well as the diversity and abundance of cyanobacteria. Higher transparency (1.21 m) and nutrient concentrations (nitrates 6.77 mgN/L ; total phosphorus 2.823 mg/L and total nitrogen 9.31 mg/L) were observed in June during the flooding, while higher algal abundance and surface water chlorophyll concentrations (116.33 µg/L) were found in the conditions of low water level in September. Species of the genera Heteroleibleinia, Tolypothrix and Phormidium were the most abundant on metaphyton mats and sediment in June, accompanied by an invasive and potentially toxic Cylindrospermopsis raciborskii in epiphytic communities on Ceratophyllum demersum and sediment in September. Among planktonic cyanobacteria, Pseudanabaena, Planktothrix and Phormidium prevailed during the flooding, while in September, C. raciborskii bloom was observed. Due to their tolerance to a wide range of temperature, light and nutritional conditions, ability of cyanobacteria to colonize available niches in freshwater biotopes can be one of the strategies to cope with or adapt to changing climatic conditions.

This study investigates water quality and hazardous substances toxic to aquatic life in a small lowland stream under different hydrological conditions. The objective was to explore links among hydrology, water chemistry and microbial contamination in a stream predominantly impacted by structural degradation of stream morphology (channelization and straightening), agricultural land use in the catchment, and by a high load of treated wastewater. Sampling was carried out during spring high (HWL, > 200 cm), summer low (LWL

Brewers’ spent grain (BSG), being the food industry lignocellulosic waste, was tested for its ability to adsorb azo dye Congo red (CR) from aqueous solutions. Effects of the initial dye concentration (30, 50, 100 and 150 mg L-1), contact time, adsorbent concentration (5, 10, and 15 g L-1), and pH (7, 8, 9 and 10) on dye removal were investigated. Dye removal was rapid within the first 60 min of the contact time. The percentage of dye removal increased with the increase in the adsorbent concentration and decrease in the initial dye concentration. The increase in pH caused reduction of the percentage removal. The percentage of CR adsorptive removal after 240 min contact time was over 85% for all runs. Dye-adsorbed biosorbent was further used as a substrate for solid-state fermentation (SSF) by the white rot fungus Trametes versicolor CCBAS AG613. Prior to solid-state fermentation experiment four white rot fungi strains, Phanerochaete chrysosporium CCBAS 570, T. versicolor CCBAS AG613, T. versicolor TV6 and Ceriporiopsis subvermispora, were screened for their ability to decolourise CR during cultivation (9 days at 27 ⁰C) on agar plates containing dye at final concentrations of 50, 100 and 150 mg L-1. Radial growth and the zone of colour change on agar plates were measured (at two perpendicular directions) every three days. Fungus T. versicolor CCBAS AG613 showed the highest decolourisation index (decolourization diameter/mycelial diameter) and was chosen for further SSF experiment. SSF of dye-adsorbed BSG (250 g BSG soaked in 350 mL of 150 mgL-1 dye solution) was carried out in a horizontal cylindrical glass flask at an ambient temperature. Temperature and weight were monitored on-line, while moisture, protein content, and colour of samples were measured after 7, 14 and 21 days of fermentation. Continuous protein content increase and weight loss were observed as a result of fungal growth and material biodegradation. Complete decolourisation of samples was not observed. However, colour determination showed the continuous increase of total colour change and colour intensity change of fermented samples, compared to their abiotic controls.

The ability of poplar sawdust, a lignocellulosic waste material, for the adsorption of cationic dye malachite green from aqueous solution was studied. Batch experiments were carried out at 25 °C and contact time of 300 min. The effects of the initial dye concentration (15, 25, 35 and 50 mg/dm3), adsorbent concentration (5, 10, 15 and 20 g/dm3), temperature (25 and 35 °C) and solution pH (2.5, 4.4 and 6.4) on dye removal were investigated. Adsorption efficiency (dye removal) was higher than 90% in all runs. The percentage of dye removal increased with increase in adsorbent concentration and decrease in the initial dye concentration. This was the most obvious within the first 30 min of contact time. The temperature had no significant effect on the percentage removal, while the decrease in pH caused the reduction of percentage removal of malachite green during the first 90 min of contact time. After 150 min of contact time, the difference of percentage dye removal was insignificant for all the experiments. The results demonstrated that poplar sawdust could be considered as effective, low-cost, environmentally friendly adsorbent for malachite green removal.