MICROPLASTICS IN LANDFILL LEACHATE - CHARACTERISTICS AND COMMON METHODS OF IDENTIFICATION

According to estimates, around 40 % of the world\u27s plastic waste production is buried in landfills, which are still a widely used approach for waste disposal. Waste undergoes a number of physical, chemical, and biological changes after being landfilled, producing landfill leachate, a highly contaminated effluent. These complex physical, chemical, and biological processes that occur in landfills also cause plastics to break into smaller fragments called microplastics (MPs) which are accumulated in landfill leachate due to their small size. Depending on waste type, the degree of degradation, the climate, the characteristics of the landfill sites, socioeconomic factors, and the applied landfilling technology, leachate composition differs between landfills. Microplastics are now emerging particle anthropogenic contaminants, and their study is generating more and more attention from the scientific community and the general public. Even though landfills have taken steps to decrease the severity of this problem, MPs continue to be produced by plastics in both current and former landfills. In this way, humans and biota may be adversely affected by landfill leachate that has been released into the environment. In order to comprehend the patterns of microplastics degradation and the most typical forms of polymers that they contain, identification and characterization of MPs from landfills is highly required. These efforts will contribute to a better understanding of how MPs from landfills affect the environment

CHEMICAL SENSORS FOR OUTDOOR AIR QUALITY MONITORING

Air pollution is a global threat leading to large impacts on human health and ecosystems. Emissions and concentrations have increased in many areas and worldwide. In some areas of Europe, air quality remains very poor, despite reduced emissions and concentrations in the environment. Currently, the most important environmental risk to human health is air pollution, and Europeans are considered the second biggest concern for the environment, right after climate change. Major problems related to air quality have an impact on human health, and in particular on respiratory diseases. In response to the problems of poor air quality, there is political, media and public interest in air quality issues. The growing public influence over air pollution challenges, including ongoing civic scientific initiatives involved in supporting air quality monitoring and targeted initiatives to raise public awareness and change behavior, has led to increasing support and demand for measures to improve air quality. Due to increasing air pollution, great efforts are being made to develop various chemical methods and chemical sensors used to measure air quality. Cheaper gas-based sensors based on the Arduino system are available today. Given their simplicity and given that they are more cost-effective, these sensors have proven to be very useful in some situations where it is necessary to detect certain gases in the air in a very short time. Several chemical methods have been developed that can also detect certain gases in the air. In this paper, only some methods by which gases and particles can be detected will be mentioned

Entrepreneurship in Međimurje

Izučavanje poduzetništva važno je zbog svoje ekonomske, socijalne i političke dimenzije, stoga se u ovom radu polazi od pojmovnog određenja poduzetništva te podjele poduzetništva. Postati poduzetnikom i osnovati vlastito poduzeće san je mnogih ljudi. Osnivanje vlastitog poduzeća donosi brojne prednosti, štoviše, nekima se poduzetništvo čini kao uzbudljiv, zanimljiv, koristan, izazovan i financijski isplativ način života, ali pošto uvijek postoji i druga strana medalje, tako je i u poduzetništvu, pa ulaskom u poduzetništvo treba snositi i određene rizike, te pokušati nadvladati nedostatke. Poduzetništvo predstavlja izraz inovativnosti određenog društva, što u tržišnim uvjetima poslovanja znači stalan stvaralački nemir. Traženje novih proizvoda, kojima će se u jakoj konkurentskoj borbi pokriti određene potrebe na tržištu i time ostvariti ciljevi poduzeća, vodi stalnom razvoju. U ovome radu se kroz povijest prikazuje razvoj poduzetništva. Poticanje poduzetništva jedan je od važnih čimbenika razvoja gospodarske strukture države, pa stoga država mora ustrajati u njezinom razvoju. Međimurje se s obzirom na „gospodarski tloris” županije, kao najsjevernija županija Hrvatske, može opisati kao „gospodarska struktura pretežno tradicionalnog, radno intenzivnog i izvozno orijentiranog karaktera”. Od samih početaka industrije u Međimurju pa do danas, kreativnost i sposobnost međimurskih poduzetnika sve više jača, a kao nagrada tome je visoka konkurentnost u odnosu na druge županije, što upućuje na pozitivne faktore dugoročnog razvitka

Monitoring of some dissolved heavy metals in surface waters of north-west Croatia from year 2016 to 2018

Heavy metals have a negative impact on environment and wildlife. In waters, heavy metals appear in two forms, as dissolved and bioavailable; and as solid and non-soluble. We monitored the concentration of dissolved copper, nickel, manganese and iron in water samples at five river locations of north-west Croatia from 2016 to 2018. Concentrations of dissolved nickel measured at Melačka river, near Vularija in Međimurje county and HE Čakovec dam, near Štefanec in Međimurje county were below 5 µg/l and could be considered as not polluted. Concentrations of dissolved copper measured at Plitvica river, near Zbela in Varaždinska county and Horvatska, near Veliko Trgovišće in Krapinsko-Zagorska county were mostly below 5 µg/l and could be considered as not polluted. At Kosteljina river near Jalšje at the Krapinsko-Zagorska county concentrations of dissolved copper were mostly below 5 µg/l; concentrations of dissolved manganese and iron were higher especially during second part of the year, with some fluctuations. For this reason, Kosteljina river could be considered as medium polluted

Application of Spectrophotometric Fingerprint in Cluster Analysis for Starch Origin Determination

Botaničko podrijetlo škroba je od velike važnosti za primjenu u industriji i proizvodnji hrane jer može bitno utjecati na svojstva krajnjeg proizvoda. Trenutno dostupne mikroskopske metode za određivanje podrijetla škroba su dugotrajne. Škrob se sastoji od amiloze i amilopektina, čiji omjer ovisi o njegovom botaničkom podrijetlu. Trijodidni ioni se obično vežu za amilozu i amilopektin, a njihovo vezivanje ovisi o podrijetlu škroba. U ovom je istraživanju mjeren apsorpcijski spektar kompleksa škrob-trijodid različitih vrsta, kao što su pšenica, krumpir, kukuruz, raž, ječam, riža, tapioka i škrob nepoznatog podrijetla, te različitih sorata iste vrste. Svaki je uzorak škroba imao specifične parametre: maksimalnu valnu duljinu pika za kompleks škrob-trijodid (λmax/nm), maksimalnu promjenu apsorbancije pri λmax (ΔA) i pomak λmax prema uzorku škroba nepoznatog botaničkog podrijetla. Vidljivi je dio apsorpcijskog spektra (500-800 nm) za svaki uzorak škroba dao jedinstveni otisak, koji je zatim obrađen klaster analizom. Tom su analizom podaci razdvojeni u dva klastera, jedan klaster žitarica i drugi klaster krumpira, tapioke i riže. Unutar klastera škrobova žitarica u podklastere su se izrazito razdvojili škrobovi pšenice, ječma i raži od kukuruznih škrobova. Podaci o sortama dobro su se grupirali unutar istog podklastera. Predložena metoda, koja kombinira klaster analizu i podatke dobivene mjerenjem apsorbancije vidljivog dijela spektra kompleksa škrob-trijodid, uspješno je razvrstala škrobove na osnovi njihove pripadnosti vrstama te sortama unutar iste vrste. Metoda je jednostavnija i praktičnija za uporabu od standardnih dugotrajnih metoda.The botanical origin of starch is of importance in industrial applications and food processing because it may influence the properties of the final product. Current microscopic methods are time-consuming. Starch consists of an origin-dependent amylose/amylopectin ratio. Triiodide ions bind characteristically to the amylose and amylopectin depending on the botanical origin of the starch. The absorbance of the starch-triiodide complex was measured for wheat, potato, corn, rye, barley, rice, tapioca and unknown origin starch, and within the different cultivars. Each starch sample had specific parameters: starch-triiodide complex peak wavelength maximum (λmax/nm), maximum absorbance change at λmax (ΔA) and λmax shift towards the unknown origin starch sample values. The visible absorption spectra (500-800 nm) for each starch sample were used as a unique fingerprint, and then elaborated by cluster analysis. The cluster analysis managed to distinguish data of two clusters, a cereal type cluster and a potato/tapioca/rice starch cluster. The cereal subclusters extensively distinguished wheat/barley/rye starches from corn starches. Data for cultivars were mostly in good agreement within the same subclaster. The proposed method that combines cluster analysis and visible absorbance data for starch-triiodide complex was able to distinguish starch of different botanical origins and cultivars within the same species. This method is simpler and more convenient than standard time-consuming methods

DYNAMICS OF NITRATES, PHOSPHATES AND DETERGENTS IN THE UNDERGROUND WATER OF MEDJIMURJE COUNTY WATER SUPPLY SYSTEM

Na području Međimurja nalaze se izdašna nalazišta podzemnih voda visoke kakvoće. Podzemne vode crpe se za pitku vodu na dva vodocrpilišta – Nedelišće (šest zdenaca) i Prelog (dva zdenca). U radu su istraživani pokazatelji antropogenog utjecaja na podzemne vode: sadržaj nitrata, fosfata i deterdženata. Analizirani su podaci o laboratorijski utvrđenom sadržaju nitrata, fosfata i deterdženata u podzemnoj vodi od 2006. – 2014. godine na vodocrpilištima Nedelišće i Prelog, prikupljeni podaci o količini oborina i razini podzemnih voda. Voda iz vodocrpilišta Nedelišće sadrži manje koncentracije nitrata u odnosu na onu iz vodocrpilišta Prelog. Od 2006. do 2010. godine koncentracija nitrata bila je u stalnom opadanju. Poslije otkupa zemljišta i uzgoja djeteline na vodocrpilištu Nedelišće došlo je do značajnog smanjenja koncentracije nitrata u vodi. Poplave i oborine 2011. do 2014. godine imale su za posljedicu povećanje koncentraciju nitrata (do 12 mg/L). Blizina naselja (zdenac 2, Nedelišće) i intenzivna poljoprivreda (Prelog) povećavaju razinu nitrata. Utvrđene vrijednosti svih analiziranih pokazatelja nalaze se ispod maksimalno dozvoljene koncentracije.Medjimurje county is rich in ground waters. Ground waters are exploited within two water wells – Nedelišće (six wells) and Prelog (two wells). In this paper we investigated some of the main parameters of anthropogenic origin in ground waters: nitrates, phosphates and detergents. We analysed these parameters in a period from 2006 to 2014, on both water wells; Nedelišće and Prelog. We also analysed the influence of the precipitation (quantity and distribution) and flood on ground waters and their correlation with measured parameters. Nitrate concentrations in water well Nedelišće obtained lower concentration compared to water well Prelog. In a period from 2006 to 2010 nitrate concentrations were constantly decreasing. From 2011 to 2014 floods and precipitations caused increase of nitrate concentrations (up to 12 mg/L). The highest nitrate concentrations were observed in well closest to the inhabited area (Nedelišće) and in the area with the intensive agricultural production (Prelog). All investigated parameter concentrations were below maximum acceptable – tolerant concentration

Wastewater treatment in the city of Koprivnica

Based on the concept of sustainable development, water must be stored and protected for present and future generations. This also means saving the water through wastewater treatment. The primary role of the wastewater treatment plants is to treat wastewaters up to a satisfactory level of quality as close as possible to the natural state. The central wastewater treatment plant (WWTP) of the City of Koprivnica treats wastewater including the tertiary wastewater. Due to considerable fluctuations in wastewater volumes and loads, sequential batch reactor (SBR) technology was selected as the best solution for wastewater treatment. The final stage of treatment at the WWTP of the City of Koprivnica is the process of sludge treatment by aerobic stabilization, dehydration and MID-MIX technology, which produces a chemically inert powder – solidificate. Solidificate can be used in civil engineering or it can be disposed to landfill without environmental impact. This paper analyses the physical-chemical indicators of wastewater quality (chemical oxygen demand - COD, biological oxygen demand - BOD5, total nitrogen, total phosphorus, suspended matter) on wastewater samples from the WWTP of the City of Koprivnica in a period from 2014 to 2016. The results indicate that the treated wastewater has a satisfactory quality and that the WWTP of the City of Koprivnica works efficiently

Farmaceutski ksenobiotici u okolišu

Farmaceutski ksenobiotici su tvari koje su strane u okolišu jer ne nastaju prirodnim putem već u okoliš dolaze kroz antropogene aktivnosti. Prilikom proizvodnje, korištenja i biotransformacije raznih vrsta farmaceutika u medicini i agronomiji, veliki dio istih u nekom obliku završi u okolišu te na taj način postaju prijetnja okolišu. S obzirom na različite izvore i načine na koji farmaceutici dospijevaju najčešće u vodu, zemlju i zrak, njihove koncentracije variraju te su za njihovo određivanje potrebne analitičke metode kojima se mogu određivati niske koncentracije. Na određenim rizičnim točkama potrebna je sanacija kontaminiranoga područja, vode i tla. Sanacija se vrši kroz remedijacijske pristupe i napredne oksidacijske procese

Surfactants: Methods for determination and removal of surfactants in environment

Površinski aktivne tvari ili tenzidi su tvari koje smanjuju površinsku napetost tekućina. Iako je danas većina tenzida biorazgradiva i ekološki prihvatljiva važno ih je kvantificirati jer lako dospijevaju u okoliš i zbog svojih svojstava imaju toksično djelovanje na organizme, sprječavaju razmjenu kisika na površini, te se akumuliraju u mikroorganizmima, biljkama, životinjama, sedimentu i tlu. Analitičke metode kojima se određuju tenzidi mogu se podijeliti u nekoliko skupina: titracijske (vizualne, potenciometrijske, tenzidimetrijske, turbidimetrijske), spektrofotometrijske (MBAS-metoda), kromatografske (tekućinska kromatografija visoke djelotvornosti-HPLC, tankoslojna kromatografija, plinska), analiza injektiranjem u protok i dr. Uklanjanje površinski aktivnih tvari iz vode provodi se na uređajima za pročišćavanje otpadnih voda fizikalno-kemijskim i biološkim postupcima dok se u kanalizacijskom sustavu i okolišu odvija se biorazgradnja tenzida.Surfactants reduce the surface tension of liquids. Surfactants are mostily biodegradable and environmentally friendly, it is still important to quantify them because they can easily reach the environment and couse toxic effects in organisms, they are a barier for surface oxygene exchange, and they accumulate in microorganisms, plants, animals, sediment and soil. Analytical methods usualy used for surfactant analysis are: titrations (visual, potentiometric, tensidimetric, turbidimetric), spectrophotometric (MBAS-method), chromatographic (high performance liquid chromatography-HPLC, thin layer chromatography), flow-injection methods, etc. Removal of surfactants from waters is carried out on wastewater treatment plants by physico-chemical and biological processes and trough the biodegradation in the sawage system and in environment

Biosenzori za praćenje teških metala i toksičnih spojeva u okolišu

Praćenje zagađenja okoliša bitan je zadatak u njegovom očuvanju, a pojednostavljenje metodologije za praćenje polutanata imperativ. Teški metali i različiti toksični spojevi posebno su opasni jer se tijekom vremena akumuliraju u biljkama i životinjama. Iz tog su razloga razvijene različite metode pomoću kojih se određuje njihova koncentracija u okolišu. Biosenzori danas predstavljaju brzo i pouzdano rješenje za praćenje zagađenja okoliša uzrokovanog različitim toksičnim spojevima i metalima. Minijaturizacija senzora omogućila je in situ mjerenja, čime se isključuju dugotrajna i ponekad skupa mjerenja u laboratorijima. U radu je prikazan kratak pregled nekih biosenzora te njihova primjena u detekciji i praćenju teških metala i toksičnih spojeva u okolišu