Nitrogen Removal from Municipal Landfill Leachate

The aim of this work was to investigate the efficiency of nitrogen removal from municipal landfill leachate with a microbial culture in 3 L batch bioreactor. The microbial culture, originating from landfill leachate, was prepared by an enrichment culture technique. Organic compounds measured as chemical oxygen demand (COD) of 400–600 mg L–1 and high concentrations of ammonium nitrogen (NH4 +-N) 270–312 mg L–1 characterized the landfill leachate as a mature leachate. The rate of ammonium nitrogen removal was 24.5 mg NH4 +-N L–1 h–1. Nitrification rate was 20.1 mg NOx–-N L–1 h–1. Denitrification was performed with the addition of sodium acetate as external carbon source in ratio C/N 2 and 4. Sodium acetate was insufficient for complete denitrification at C/N 2. Complete denitrification at C/N 4 was performed at denitrification rate 8.3 mg NO3–-N L–1 h–1

Nitrogen Removal from Municipal Landfill Leachate

The aim of this work was to investigate the efficiency of nitrogen removal from municipal landfill leachate with a microbial culture in 3 L batch bioreactor. The microbial culture, originating from landfill leachate, was prepared by an enrichment culture technique. Organic compounds measured as chemical oxygen demand (COD) of 400–600 mg L–1 and high concentrations of ammonium nitrogen (NH4 +-N) 270–312 mg L–1 characterized the landfill leachate as a mature leachate. The rate of ammonium nitrogen removal was 24.5 mg NH4 +-N L–1 h–1. Nitrification rate was 20.1 mg NOx–-N L–1 h–1. Denitrification was performed with the addition of sodium acetate as external carbon source in ratio C/N 2 and 4. Sodium acetate was insufficient for complete denitrification at C/N 2. Complete denitrification at C/N 4 was performed at denitrification rate 8.3 mg NO3–-N L–1 h–1

Speciation of nano and ionic form of silver with capillary electrophoresis-inductively coupled plasma mass spectrometry.

Research in the area of new nanomaterials has been given high priority as having an enormous economic potential. Due to marked antimicrobial effect, silver nanoparticles (AgNPs) are one of the most commercialized and successfully exploited nanomaterials in a wide range of medical and consumer products.In biological and environmental compartments, AgNPs undergo different transformations including interaction with organic molecules, such as proteins, and dissolution. Hyphenated systems consisting of capillary electrophoresis (CE) coupled to sensitive element detection like ICP-MS can be considered as the promising methods for speciation analysis of AgNPs. Here, we investigated applicability of different CE methods hyphenated to ICP-MS for speciation of AgNPs in biological systems.The paper presents approach to analyze species formed in interaction of AgNPs with metallothionein (MT) as model protein. As AgNPs might be coated by MTs in bio-fiuids, we installed first a CE-speciation method for MT-1 and MT-2. Although this separation was successful, no reproducible and well separated peaks for AgNPs or Ag* were achieved. Therefore, we focused on developing methods for separating MT-1, MT-2, Ag* and AgNPs. Several buffer conditions were tested to improve their separation and to minimize Ag-sticking to capillary walls. All compounds of interest in this paper, i.e. MT-1, MT-2, Ag+ and AgNPs, were well separated from each other using tetramethyl-ammoniumhydroxide as electrolyte. In mixed samples, we observed Ag+ being completely associated with MT-1, while Ag*-association with MT-2 was less: The highest quantity of Ag* was associated with a compound having low Cd-concentration, while another relevant fraction was bound to MT-2. Free Ag* was also seen in minor amounts whereas another Ag-peak at 8.13 min remains unknown. Most AgNPs remained free. AgNPs were only little associated with MT-1, the latter being split into two peak signals, whereas association with MT-2 was high. Only 15% of AgNPs remained unbound.We demonstrated CE hyphenated to the ICP-MS as promising and elegant technique to study AgNPs in biological systems. (C) 2018 Elsevier B.V. All rights reserved

Oxidative stress response in neural stem cells exposed to different superparamagnetic iron oxide nanoparticles

Igor M Pongrac,1 Ivan Pavičić,2 Mirta Milić,2 Lada Brkič Ahmed,1 Michal Babič,3 Daniel Horák,3 Ivana Vinković Vrček,2 Srećko Gajović1 1School of Medicine, Croatian Institute for Brain Research, University of Zagreb, 2Institute for Medical Research and Occupational Health, Zagreb, Croatia; 3Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic Abstract: Biocompatibility, safety, and risk assessments of superparamagnetic iron oxide nanoparticles (SPIONs) are of the highest priority in researching their application in biomedicine. One improvement in the biological properties of SPIONs may be achieved by different functionalization and surface modifications. This study aims to investigate how a different surface functionalization of SPIONs – uncoated, coated with D-mannose, or coated with poly-L-lysine – affects biocompatibility. We sought to investigate murine neural stem cells (NSCs) as important model system for regenerative medicine. To reveal the possible mechanism of toxicity of SPIONs on NSCs, levels of reactive oxygen species, intracellular glutathione, mitochondrial membrane potential, cell-membrane potential, DNA damage, and activities of SOD and GPx were examined. Even in cases where reactive oxygen species levels were significantly lowered in NSCs exposed to SPIONs, we found depleted intracellular glutathione levels, altered activities of SOD and GPx, hyperpolarization of the mitochondrial membrane, dissipated cell-membrane potential, and increased DNA damage, irrespective of the surface coating applied for SPION stabilization. Although surface coating should prevent the toxic effects of SPIONs, our results showed that all of the tested SPION types affected the NSCs similarly, indicating that mitochondrial homeostasis is their major cellular target. Despite the claimed biomedical benefits of SPIONs, the refined determination of their effects on various cellular functions presented in this work highlights the need for further safety evaluations. This investigation helps to fill the knowledge gaps on the criteria that should be considered in evaluating the biocompatibility and safety of novel nanoparticles. Keywords: superparamagnetic iron oxide nanoparticles, biocompatibility, oxidative stress, genotoxicity, murine neural stem cell

Association between arsenic exposure and biomarkers of type 2 diabetes mellitus in a Croatian population: A comparative observational pilot study.

Chronic exposure to high inorganic As levels in drinking water has been related to many diseases, including type 2 diabetes mellitus (T2D). The association with low and moderate As levels, however, remains controversial and has yet not been studied in European populations.This study aimed to investigate possible association between As exposure and biomarkers of T2D in Croatian population. Observation recruited 86 adults from Eastern Croatia, where groundwater is contaminated with inorganic As, and 116 adults from Western Croatia, where As levels in drinking water are low. Both populations were divided in patient groups (T2D or prediabetes) and healthy controls. Exposure was assessed by determining total As in blood and urine and As metabolites in urine.Eastern Croatian population had a significantly higher content of As in urine than Western, whereas the opposite was true for arsenobetain. Total As and As metabolites in urine positively correlated with hemoglobin A1c (HbA1c) and negatively with albuminuria.This study provides important preliminary data on the levels of As in urine and blood and their association with biomarkers of T2D in Croatian population exposed to low or moderate levels of As through drinking water as a solid basis for further research of the pathophysiological effects of such As exposure on the status and complications of diabetes

Procjena unosa bakra umjerenom konzumacijom vina

To estimate Cu exposure level from wine consumption and to assess possible health risk for moderate wine consumers, wine samples were collected from different wine-growing areas of Croatia. Median concentrations were 180 μg L-1, range (76 to 292) μg L-1, in commercial wines and 258 μg L-1, range (115 to 7600) μg L-1, in homemade wines (P>0.05). Maximum permitted level of 1000 μg L-1 was exceeded in three homemade wines. However, daily intake of Cu from wine (in the range from 0.02 mg d-1 to 1.52 mg d-1) estimated from Cu concentration in all wine samples is lower than the tolerable upper intake level of 5 mg d-1 proposed by the EU Scientifi c Committee on Food and does not present a risk to moderate wine consumers.Kako bi se procijenila razina izloženosti bakru prilikom konzumacije vina te utvrdili mogući zdravstveni rizici za umjerene potrošače vina, skupljeni su i ispitani uzorci vina iz različitih vinogradarskih područja Hrvatske. Koncentracije Cu bile su u rasponu od 76 μg L-1 do 292 μg L-1 (medijan 180 μg L-1) u komercijalnim vinima te od 115 μg L-1 do 7.600 μg L-1 (medijan 258 μg L-1) u vinima domaće proizvodnje (P>0,05). U tri ispitana vina domaće proizvodnje koncentracija Cu bila je iznad najviše dopuštene od 1000 μg L-1. Međutim, izračunani dnevni unos Cu u slučaju konzumacije ispitanih vina (u rasponu od 0,02 mg d-1 do 1,52 mg d-1) ne prelazi gornju granicu tolerancije unosa od 5 mg d-1 te nije zdravstveni rizik umjerenim potrošačima vina