Publications

The occurrence of contaminants of emerging concern in Slovenian and Croatian wastewaters and receiving Sava river

Česen, M., Ahel, M., Terzić, S., Heath, D. J., Heath, E. The occurrence of contaminants of emerging concern in Slovenian and Croatian wastewaters and receiving Sava river. Science of the Total Environment, 2019, 650, 2446-2453, doi: 10.1016/j.scitotenv.2018.09.238. 

Abstract: This study investigated the occurrence of 48 contaminants of emerging concern (CECs) in wastewater effluents from three Slovenian and three Croatian waste water treatment plants (WWTPs) representing the major inputs into the upper and middle course of the Sava River and simultaneously in the Sava River itself. Two sampling campaigns were carried out (May and July 2017). Samples were extracted using solid-phase extraction and analysed by gas chromatography - mass spectrometry. In effluents, 23 CECs were >LOQ with caffeine and the UV-filter 4-hydroxybenzophenone (H-BP) present in the highest concentrations (<49,600 ng L−1and <28,900 ng L−1, respectively) and most frequently detected (detection frequency; DFr > 83.3%). Bisphenol B and E were detected for the first time in WW from Velika Gorica (May) and Zaprešić (July), respectively. In surface water (SW), 19 CECs were detected >LOQ with CAF again being the most abundant and most frequently detected (DFr = 92.9%). Bisphenols AP, CL2, P and Z were detected >LOQ for the first time in European SW. Active pharmaceutical ingredients naproxen, ketoprofen, carbamazepine and diclofenac; the preservative methyl paraben; CAF and UV-filter HM-BP were the most abundant CECs in SW and WW. An increasing trend in the total CEC load downstream was observed, indicating the cumulative effects of individual sources along the river. The Croatian Zaprešić, Zagreb and Velika Gorica WWTP effluents contributed the most towards the enhanced loads of the CECs studied probably due to their size or insufficient treatment. HM-BP was the only compound found at a levels exhibiting high environmental risk (RQ = 1.13) downstream from Ljubljana and Domžale-Kamnik WWTPs. Other SW samples that contained HM-BP, ibuprofen (API) and/or benzyl paraben (preservative) posed a medium risk to the environment. The results suggest the need for further monitoring of CECs in the Sava River Basin.

Sulfur (34S/32S) isotope composition in gypsum and implications for deep cave formation on the Nullabor Plain, Australia

Lipar, M., Ferk, M., Lojen, S., Barham, M. Sulfur (34S/32S) isotope composition in gypsum and implications for deep cave formation on the Nullabor Plain, Australia. International Journal of Speleology, 2019, 48, 2, 9 pp., https://doi.org/10.5038/1827-806X.48.1.2196. 

Abstract: Large deep caves with little relation to surface topography are distinctive karst features on the Nullarbor Plain of Australia. The presence of gypsum deposits and chemoautotrophic bacteria within the caves have been suggested as evidence for cave formation and (or) enlargement via sulfuric acid speleogenesis. To test this hypothesis, the stable sulfur isotope compositions (δ34S) of both cave gypsum and surface gypsum were measured. Analyses yielded relatively high, positive δ34S values from both cave gypsum and surface gypsum, arguing against gypsum genesis via microbial chemoautotrophy, and more broadly, sulfuric acid speleogenesis. Instead, the gypsum is interpreted as forming via evaporation of seawater during the Quaternary

Application of passive capillary samplers in water stable isotope investigations of snowmelt: a case study from Slovenia

Vreča, P., Brenčič, M., Torkar, A. Application of passive capillary samplers in water stable isotope investigations of snowmelt: a case study from Slovenia. Journal of Hydrology and Hydromechanics, 2019, 67, 32-40, doi: 10.2478/johh-2018-0017. 

Abstract: In this paper we describe the use of modified passive capillary samplers (PCSs) to investigate the water isotope variability of snowmelt at selected sites in Slovenia during winter 2011/2012 and during winter 2012/2013. First, PCS with 3 fibreglass wicks covering approximately 1 m2 were tested to determine sample variability. We observed high variability in the amount of snowmelt water collected by individual wick (185 to 345 g) and in the isotope composition of oxygen (δ18O −10.43‰ to −9.02‰) and hydrogen (δ2H −70.5‰ to −63.6‰) of the collected water. Following the initial tests, a more detailed investigation was performed in winter 2012/2013 and the variability of snowmelt on the local scale among the different levels (i.e. within group, between the close and more distant groups of wicks) was investigated by applying 30 fibreglass wicks making use of Analysis Of Variance (ANOVA) and a balanced hierarchical sampling design. The amount of snowmelt water collected by an individual wick during the whole experiment was between 116 and 1705 g, while the isotope composition varied from −16.32‰ to −12.86‰ for δ18O and from −120.2‰ to −82.5‰ for δ2H. The main source of variance (80%) stems from the variability within the group of wicks (e.g. within group) while other sources contribute less than 20% of the variability. Amount weighted samples for the 2012-2013 season show no significant differences among groups, but significant differences for particular sampling events were observed. These investigations show that due to the variability within the group of wicks, a large number of wicks (> 5) are needed to sample snowmelt.

Potentially toxic elements in water, sediments and fish of the Evrotas River under variable water discharges.

Milačič, R., Zuliani, T., Vidmar, J., Bergant, M., Kalogianni, E., Smeti, E., Skoulikidis, N., Ščančar, J. Potentially toxic elements in water, sediments and fish of the Evrotas River under variable water discharges. Science of the Total Environment, 2019, 648, 1087-1096, doi: 10.1016/j.scitotenv.2018.08.123. 

Abstract: Among different stressors like drought, hydro-morphological alterations, and pollution from agricultural activities, nutrients, organic compounds and discharges from wastewater treatment plants (WWTPs), potentially toxic elements (PTE) may also contribute to the overall pollution of the Evrotas River, Greece. Nevertheless, information on pollution of elements in water and sediments in this river is scarcely documented. There is also no information available on the impact of elemental pollution from the aquatic environmental compartments on biota. To fill these gaps, in this study, water, sediment and fish samples were collected from four sampling sites along the Evrotas River under variable flow regimes (July 2015, higher discharge; June 2016, low discharge and September 2016, minimum discharge). Total and dissolved element concentrations in water samples, total and acetic acid extractable contents in sediments, and element concentrations in fish samples were determined by inductively coupled plasma mass spectrometry and significant relationships between samples were established using correlation analysis. The concentrations of PTE (Ni, Cr, Cd, As, Pb, Zn and Cu) in water were generally low, while elevated Ni and Cr contents were found in sediments (up to 150 and 300 mg/kg, respectively), with total Cr concentration in water and sediment being positively correlated. The ecological risk posed by the simultaneous presence of PTE in sediments evaluated by calculating the Probable Effect Concentration Coefficient (PEC-Q), demonstrated that PEC-Qs, which were above the critical value of 0.34, derived mostly from Cr and Ni inputs. Since their mobile sediment fraction was extremely low, Cr and Ni origin is most probably geogenic. The analysis of elements in the target fish species, the Evrotas chub, showed low to moderate PTE concentrations, with Pb being positively correlated with total Pb concentration in water. Moderate Zn concentrations found in fish samples from the Evrotas are possibly derived from pesticides and fertilizers.

Lessons learned from inter-laboratory studies of carbon isotope analysis of honey

Dunn, P. J. H., Hill, S., Cowen, S., Goenaga-Infante, H., Sargent, M., Gören, A. C., Bilsel, M., Şimşek, A., Ogrinc, N., Potočnik, D., Armishaw, P., Hai, L., Konopelko, L., Chubchenko, Y., Chesson, L. A., van der Peijl, G., Blaga, C. Posey, R., Camin, F., Chernyshev, A., Chowdhury, S. A. Lessons learned from inter-laboratory studies of carbon isotope analysis of honey. Science and Justice, 2019, 59, 9-19, doi: 10.1016/j.scijus.2018.08.003. 

Abstract: Forensic application of carbon isotope ratio measurements of honey and honey protein to investigate the degree of adulteration with high fructose corn syrup or other C4 plant sugars is well established. These measurements must use methods that exhibit suitable performance criteria, particularly with regard to measurement uncertainty and traceability - low levels of adulteration can only be detected by methods that result in suitably small measurement uncertainties such that differences of 1‰ or less can be reliably detected. Inter-laboratory exercises are invaluable to assess the state-of-the art of measurement capabilities of laboratories necessary to achieve such performance criteria. National and designated metrology institutes from a number of countries recently participated in an inter-laboratory assessment (CCQM-K140) of stable carbon isotope ratio determination of bulk honey. The same sample material was distributed to a number of forensic isotope analysis laboratories that could not participate directly in the metrological comparison. The results from these studies have demonstrated that the majority of participants provided isotope delta values with acceptable performance metrics; that all participants ensured traceability of their results; and that where measurement uncertainties were reported; these were fit-for-purpose. A number of the forensic laboratories only reported precision rather than full estimates of measurement uncertainty and this was the major cause of the few instances of questionable performance metrics. Reporting of standard deviations in place of measurement uncertainties is common practice outside metrology institutes and the implications for interpretations of small differences in isotopic compositions are discussed. The results have also highlighted a number of considerations that are useful for organisers of similar inter-laboratory studies in the future.

Potentially toxic elements in muscle tissue of different fish species from the Sava River and risk assessment for consumers

Zuliani, T., Vidmar, J., Drinčić, A., Ščančar, J., Horvat, M., Nečemer, M., Piria, M., Simonović, P., Paunović, M., Milačič, R. Potentially toxic elements in muscle tissue of different fish species from the Sava River and risk assessment for consumers. Science of the Total Environment, 2019, 650, 1, 958-969, doi: 10.1016/j.scitotenv.2018.09.083. 

Abstract: Fish from the Sava River are consumed daily by the local people: therefore, concern has been raised about the health implications of eating contaminated fish. In the present study, potentially toxic elements (PTE), such as Zn, Cu, Cr, Ni, Cd, Pb, As, Hg, and methylmercury (MeHg), were determined in ichthyofauna that are commonly consumed. PTE were determined in the fish muscle tissue. Fish were sampled at 12 locations from the source of the Sava River to its confluence with the Danube River during two sampling campaigns, namely; in 2014 under high water conditions and in 2015 under normal water conditions. Due to the different water regimes, different fish species were collected for chemical analysis. We observed that the concentrations of elements analysed in the fish muscle tissue were generally very low, except for those of Hg. Moreover, more than 90% of Hg present in the fish was in its most toxic form, namely MeHg. Especially in fish from the 2015 sampling campaign, Hg and MeHg concentrations increased with fish size, trophic level, and in the downstream direction. In addition, for Pb and As, and to some extent for Cd and Cr, spatial differences were detected in both years. The highest concentrations of PTE were detected in fish from sites with intensive industrial and agricultural activities. The consumption of fish in general does not pose a health risk for the PTE studied, except for Hg/MeHg at selected contaminated sites.

The impact of moisture sources on the oxygen isotope composition of precipitation at a continental site in central Europe

Krklec, K., Domínguez-Villar, D., Lojen, S. The impact of moisture sources on the oxygen isotope composition of precipitation at a continental site in central Europe. Journal of Hydrology, 2018, 561, 810-821, doi: 10.1016/j.jhydrol.2018.04.045. 

Abstract: The stable isotope composition of precipitation records processes taking place within the hydrological cycle. Potentially, moisture sources are important controls on the stable isotope composition of precipitation, but studies focused on this topic are still scarce. We studied the moisture sources contributing to precipitation at Postojna (Slovenia) from 2009 to 2013. Back trajectory analyses were computed for the days with precipitation at Postojna. The moisture uptake locations were identified along these trajectories using standard hydrometeorological formulation. The moisture uptake locations were integrated in eight source regions to facilitate its comparison to the monthly oxygen isotope composition (δ18O values) of precipitation. Nearly half of the precipitation originated from continental sources (recycled moisture), and >40% was from central and western Mediterranean. Results show that moisture sources do not have a significant impact on the oxygen isotope composition at this site. We suggest that the large proportion of recycled moisture originated from transpiration rather than evaporation, which produced water vapour with less negative δ18O values. Thus the difference between the oceanic and local vapour source was reduced, which prevented the distinction of the moisture sources based on their oxygen isotope signature. Nevertheless, δ18O values of precipitation are partially controlled by climate parameters, which is of major importance for paleoclimate studies. We found that the main climate control on Postojna δ18O values of precipitation is the surface temperature. Amount effect was not recorded at this site, and the winter North Atlantic Oscillation (NAO) does not impact the δ18O values of precipitation. The Western Mediterranean Oscillation(WeMO) was correlated to oxygen stable isotope composition, although this atmospheric pattern was not a control. Instead we found that the link to δ18O values results from synoptic scenarios affecting WeMO index as well as temperature. Therefore, interpretation of δ18O values of precipitation in terms of climate is limited to surface temperature, although at least half of the variability observed still depends on unknown controls of the hydrological cycle.

Determination of polybrominated diphenyl ethers in human serum by gas chromatography - inductively coupled plasma mass spectrometry

Bergant, M., Milačič, R., Ščančar, J. Determination of polybrominated diphenyl ethers in human serum by gas chromatography - inductively coupled plasma mass spectrometry. Journal of Chromatography A, 2018, 1572, 112-118, doi: 10.1016/j.chroma.2018.08.043. 

Abstract: Polybrominated diphenyl ethers (PBDEs) are flame retardants that are added to a wide range of consumer products. Due to their extensive use in the past, their presence has been documented in multiple environmental compartments and living organisms, including humans. To assess the exposure of humans to PBDEs, a new simple, reliable, and sensitive method was developed for the determination of six PBDE congeners (BDE 28, BDE 47, BDE 99, BDE 100, BDE 153, BDE 154) in human serum by gas chromatography–inductively coupled plasma mass spectrometry (GC-ICP-MS). The PBDEs were extracted from 1 mL ofserum by 30 min of mechanical shaking with formic acid. Subsequently, 2 mL of iso-octane was added and 30 min of mechanical shaking was applied. For clean-up of the extract Florisil column was applied. The analytical method was validated by analysis of human serum standard reference materials SRM 1957 (Non-Fortified Human Serum) and SRM 1958 (Fortified Human Serum). Good agreement of the determined concentrations with those certified was found. The repeatability and reproducibility of the analytical method was within 5.9% and 6.1%, respectively, whereas the limits of detection (LODs) for the PBDEs analysed were between 0.0016 and 0.0039 ng mL−1 wet weight (ww). The feasibility of the method was tested by analysing human serum samples. In this study, the determined concentrations in sera were in a range similar to that of as those reported for certain other European countries.

The occurrence and source identification of bisphenol compounds in wastewaters

Česen, M., Lenarčič, K., Mislej, V., Levstek, M., Kovačič, A., Cimrmančič, B., Uranjek Ževart, N., Kosjek, T., Heath, D. J., Sollner Dolenc, M., Heath, E. The occurrence and source identification of bisphenol compounds in wastewaters. Science of the Total Environment, 2018, 616-617, 744-752, doi: 10.1016/j.scitotenv.2017.10.252. 

Abstract: This study reports the occurrence of eight bisphenols (BPs): bisphenol AF (BPAF), bisphenol AP (BPAP), bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), bisphenol F (BPF), bisphenol S (BPS) and bisphenol Z (BPZ) in wastewaters (WWs). Sample preparation involved pre-concentration with SPE cartridges (Oasis HLB), followed by derivatization using N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide with 1% tert-butyldimethylchlorosilane. Chemical analysis was based on gas chromatography–mass spectrometry. A validated method with limits of detection (LODs) at ng L− 1 range was applied to WWs collected at five Slovene wastewater treatment plants (WWTPs) and WW inflows from industrial, commercial and residential sources entering the sewerage systems of two catchments (Domžale-Kamnik (DK) and Ljubljana (LJ)). The presence of all BPs was confirmed in three inflows in DK and two inflows in the LJ catchments. High cumulative concentrations of all BPs were determined in WW from food processingfacilities (LJ: 3030 ng L− 1 and DK: 599 ng L− 1). A high detection frequency was observed in the WW from two textile cleaning companies (6 BPs for LJ and 8 BPs for DK). The analysis of WW from WWTPs revealed that only BPF (36.7 ng L− 1) and BPS (40.6 ng L− 1) were > LODs in the influents, whereas other BPs were detected also in the effluents. BPZ was found in the highest concentration (403 ng L− 1 at WWTP-DK). WW collected at this WWTP also contained the highest amount of BPE (238 ng L− 1). Although BPs removal could not be directly compared between the WWTPs, with the exception of BPAP and BPB in the case of two smaller WWTPs (6.39%–43.2%) bisphenols were in general highly removed (≥ 96.2%). Finally, levels of BPC > LOD are reported for first time (WWTP in the DK catchment: 1.01 ng L− 1–11.8 ng L− 1; LJ inflow from food processing plant up to 2560 ng L− 1).

Geochemistry of sedimentary organic matter and trace elements in modern lake sediments from transitional karstic land-sea environment of the Neretva River delta (Kuti Lake, Croatia)

Ivanić, M., Lojen, S., Grozić, D., Jurina, I., Škapin, S. D., Troskot-Čorbić, T., Mikac, N., Juračić, M., Sondi, I. Geochemistry of sedimentary organic matter and trace elements in modern lake sediments from transitional karstic land-sea environment of the Neretva River delta (Kuti Lake, Croatia). Quaternary International, 2018, 494, 286-299, doi:10.1016/j.quaint.2017.03.050. 

Abstract: This paper investigates recent sedimentation processes and geochemistry of sedimentary organic matter (SOM) and trace elements in a unique semi-enclosed lacustrine sedimentation system in a transitional land-sea environment of the Neretva River delta. The results have shown that the influence of the Neretva Riveron the lake sedimentation processes is limited to short-term flood events carrying terrigenous loads, while the authigenic formation of nanostructured calcite is the primary source of sediments in the recent past. The enhanced release of biogenic CO2 into the pore water, deriving from the decomposition of SOM, acts as a major contributor to this process. The occurrence of early formed syngenetic and diagenetic pyrite indicates the existence of oxygen-depleted conditions in the investigated system in the recent past. The input of terrigenous material was identified as the main source of trace elements (Pb, Cu, Zn, Sn) in the lake sediments. The distribution of redox sensitive elements (Mo, Tl, V) particularly depends on the oxygen deficiency and the formation of sedimentary pyrite. The human impact in the study area is negligible, although somewhat elevated concentrations of Sn were found in the surface sediment layers. Finally, the results obtained indicate that the Kuti Lake represents a unique lacustrine environmentwhich can be viewed as an isolated sedimentological and biogeochemical system in the Neretva River delta.

Authigenic mineralization in low-rank coals from the Velenje Basin, Slovenia

Kanduč, T., Vreča, P., Gregorin, Š., Vrabec, M., Vrabec, M., Grassa, F. Authigenic mineralization in low-rank coals from the Velenje Basin, Slovenia. Journal of Sedimentary Research, 2018, 88, 2, 201-213, doi: 10.2110/jsr.2018.7. 

Abstract: The purpose of this study is to characterize sedimentologically and isotopically authigenic mineralization and low-rank coals (lignite) from the Velenje basin, Slovenia. Six structural types of calcite mineralization in a fine lignite gelified matrix were recognized, namely: (A) laminae and thin beds, (B) small lenses and lenticular bodies, (C) dispersed mineral matter in minute detritus, (D) calcite-substituted xylite fragments, (E) encrusted xylite fragments, and (F) calcite-coated and calcite-filled pores. Scanning electron microscopy revealed that in parts the calcified lignite is almost pure calcite. The carbon (–4.3 to +16.4‰) and oxygen (–14.5‰ to –6.6‰) isotopic composition indicates a carbonate precipitation temperature of between 5.7 and 45.5°C. The δ¹³C_org. values and δ¹⁵N_bulk of organic compounds were from –29.4‰ to –23.7‰ and from +1.8‰ to +5.9‰, respectively. The lower δ¹³C_org. values (up to –29.4‰) in the Velenje lignite indicate a high degree of gelification, while the δ¹⁵N_bulk values (up to +5.9‰) are indicative of intense mineralization. Furthermore, a carbon isotope fractionation factor (ε_TOC) of more than 32% suggests that unlike in recent lake sediments from Slovenia, Croatia, and Argentina, where oxic processes dominate, there was intense microbial activity (methane formation in anoxic conditions). In addition, the ε_TOC values in the Velenje samples are unrelated to mineralization type but are related to the degree of gelification (bacterial activity). The investigation of mineral occurrence is important since cleat-filling minerals reduce coal permeability, which in turn can trigger gas outbursts and inhibit gas extraction.

Seasonal and spatial variations in the occurrence, mass loadings and removal of compounds of emerging concern in the Slovene aqueous environment and environmental risk assessment

Česen, M., Heath, D. J., Krivec, M., Košmrlj, J., Kosjek, T., Heath, E. Seasonal and spatial variations in the occurrence, mass loadings and removal of compounds of emerging concern in the Slovene aqueous environment and environmental risk assessment. Environmental Pollution, 2018, 242 A, 143-154, doi: 10.1016/j.envpol.2018.06.052. 

Abstract: This study reports the development of a multi-residue method for determining 48 compounds of emerging concern (CEC) including three diclofenac transformation products (TP) in Slovenian wastewater (WW) and surface water (SW). For solid-phaseextraction (SPE), Oasis™ Prime cartridges were favoured over Oasis HLB™. The validated method was then applied to 43 SW and 52 WW samples collected at nine locations. Ten bisphenols in WW and 14 bisphenols in SW were traced in Europefor the first time. Among all of the 48 targeted CEC, 21 were >LOQ in the influents and 20 in the effluents. One diclofenac TP was also quantified in WWs (3.04–78.1 ng L−1) for the first time. As expected, based on mass loads in the wastewater treatment plant influents, caffeine is consumed in high amounts (105,000 mg day−11000 inhab.−1) in Slovenia, while active pharmaceutical ingredients (APIs) are consumed in lower amounts compared to other European countries. Removal was lower in winter in the case of four bisphenols (17–78%), one preservative (36%) and four APIs (-14–91%), but remained constant for caffeine, one API, two UV-filters and three preservatives (all >85.5%). Overall, a constructed wetland showed the lowest (0–80%) and most inconsistent removal efficiencies (SD > 40% for some CECs) of CECs including caffeine, two UV-filters, two preservatives and two APIs compared to other treatment technologies. The method was also able to quantify Bisphenol S in SW (<36.2 ng L−1). Environmental risk was assessed via risk quotients (RQs) based on WW and SW data. Two UV-filters (oxybenzone and dioxybenzone), estrone and triclosan, despite their low abundance posed a medium to high environmental risk with RQs between 0.282 (for HM-BP) and 15.5 (for E1).

Ion microprobe δ18O analyses to calibrate slow growth rate speleothem records with regional δ18O records of precipitation

Domínguez-Villar, D., Lojen, S., Krklec, K., Kozdon, Richard, E., Lawrence R., Cheng, H. Ion microprobe δ18O analyses to calibrate slow growth rate speleothem records with regional δ18O records of precipitation. Earth and Planetary Science Letters, 2018, 482, 367-376, doi: 10.1016/j.epsl.2017.11.012. 

Abstract: Paleoclimate reconstructions based on speleothems require a robust interpretation of their proxies. Detailed transfer functions of external signals to the speleothem can be obtained using models supported by monitoring data. However, the transferred signal may not be stationary due to complexity of karst processes. Therefore, robust interpretations require the calibration of speleothem records with instrumental time series lasting no less than a decade. We present the calibration of a speleothem δ18O record from Postojna Cave (Slovenia) with the regional record of δ18O composition of precipitation during the last decades. Using local meteorological data and a regional δ18O record of precipitation, we developed a model that reproduces the cave drip water δ18O signal measured during a two-year period. The model suggests that the average water mixing and transit time in the studied aquifer is 11 months. Additionally, we used an ion microprobe to study the δ18O record of the top 500 μm of a speleothem from the studied cave gallery. According to U–Th dates and 14C analyses, the uppermost section of the speleothem was formed during the last decades. The δ18O record of the top 500 μm of the speleothem has a significant correlation (r2=0.64; p-value <0.001) with the modelled δ18O record of cave drip water. Therefore, we confirm that the top 500 μm of the speleothem grew between the years 1984 and 2003 and that the speleothem accurately recorded the variability of the δ18O values of regional precipitation filtered by the aquifer. We show that the recorded speleothem δ18O signal is not seasonally biased and that the hydrological dynamics described during monitoring period were stationary during recent decades. This research demonstrates that speleothems with growth rates <50 μm/yr can also be used for calibration studies. Additionally, we show that the fit of measured and modelled proxy data can be used to achieve annually resolved chronologies in speleothems that were not actively growing at the time of collection and/or that do not record annual laminae.

Suspect and untargeted screening of bisphenol S metabolites produced by in vitro human liver metabolism

Gys, C., Kovačič, A., Huber, C., Yin Lai, F., Heath, E., Covaci, A. Suspect and untargeted screening of bisphenol S metabolites produced by in vitro human liver metabolism. Toxicology Letters, 2018, 295, 115-123, doi: 10.1016/j.toxlet.2018.05.034. 

Abstract: Bisphenol S (BPS) is increasingly used as substitute for bisphenol A, resulting in higher potential of human exposure to this compound. Yet, information on the human metabolism of BPS is limited. Hence, current biomonitoring studies rely only on the measurement of BPS itself, leading to a potential underestimation of assessing human exposure to this emerging contaminant. The aims of this study were to investigate the in vitro metabolic pathways of BPS using human liver microsomes and cytosol fractions and propose in vitro metabolites for evaluation in pharmacokinetics studies. Liquid chromatography coupled to quadrupole time-of-flight high-resolution mass spectrometry was used for the screening, identification, and structural elucidation of Phase I and II metabolites of BPS for the first time. Metabolite identification was performed using two complementary workflows: suspect and untargeted screening. Two Phase I metabolites were formed through hydroxylation of the phenolic rings. Four Phase II metabolites were formed through conjugation with glucuronic acid or sulfate. Three of these metabolites, namely dihydroxy-BPS, hydroxy-BPS-glucuronide and hydroxy-BPS-sulfate were identified and structurally elucidated for the first time. As such, we provide an expanded set of in vitro biotransformation products of BPS, which can potentially support a reliable assessment of BPS exposure in future biomonitoring studies.

Environmental status of the NE Adriatic Sea, Istria, Croatia: insights from mussel Mytilus galloprovincialis condition indices, stable isotopes and metal(loid)s.

Kanduč, T., Šlejkovec, Z., Falnoga, I., Mori, N., Budič, B., Kovačić, I., Pavičić Hamer, D., Hamer, B. Environmental status of the NE Adriatic Sea, Istria, Croatia: insights from mussel Mytilus galloprovincialis condition indices, stable isotopes and metal(loid)s. Marine Pollution Bulletin, 2018, 126, 525-534, doi: 10.1016/j.marpolbul.2017.09.052. 

Abstract: The environmental status of the marine environment in the NE Adriatic Sea was assessed, using as a bioindicator species the Mediterranean mussel Mytilus galloprovincialis Lamarck, 1819. Samples were collected seasonally from mariculturesites and from major Istrian ports between the years 2010 and 2013. The condition indices of mussels ranged from 13.3 to 20.9% at mariculture sites and from 14.3 to 23.3% at port locations. The seasonally δ13CDIC values of seawater varied between − 10.9 to 0.7‰. Pollution by sewage sludge (based on δ15N values) was confirmed only in two ports. Tissue concentrations of Mn, Co, Ni, Cu, Zn, Se, Cd, and Pb were significantly higher in the tissue of the mussels collected from the ports (polluted sites). Arsenobetaine was the major As compound present in the samples and there was no significant difference in the levels of total As in mussel tissues from mariculture and port sites.

Ensuring food integrity by metrology and FAIR data principles

Rychlik, M., Zappa, G., Anorga, L., Belc, N., Castanheira, I., Donard, O. F. X., Kouřimská, L., Ogrinc, N., Presser, K., Zoani, C., et al. Ensuring food integrity by metrology and FAIR data principles. Frontiers in Chemistry, 2018, 6, 49-1-49-7, doi: 10.3389/fchem.2018.00049. 

Abstract: Food integrity is a general term for sound, nutritive, healthy, tasty, safe, authentic, traceable, as well as ethically, safely, environment-friendly, and sustainably produced foods. In order to verify these properties, analytical methods with a higher degree of accuracy, sensitivity, standardization and harmonization and a harmonized system for their application in analytical laboratories are required. In this view, metrology offers the opportunity to achieve these goals. In this perspective article the current global challenges in food analysis and the principles of metrology to fill these gaps are presented. Therefore, the pan-European project METROFOOD-RI within the framework of the European Strategy Forum on Research Infrastructures (ESFRI) was developed to establish a strategy to allow reliable and comparable analytical measurements in foods along the whole process line starting from primary producers until consumers and to make all data findable, accessible, interoperable, and re-usable according to the FAIR data principles. The initiative currently consists of 48 partners from 18 European Countries and concluded its “Early Phase” as research infrastructure by organizing its future structure and presenting a proof of concept by preparing, distributing and comprehensively analyzing three candidate Reference Materials (rice grain, rice flour, and oyster tissue) and establishing a system how to compile, process, and store the generated data and how to exchange, compare them and make them accessible in data bases.

Investigation of the behaviour of zero-valent iron nanoparticles and their interactions with Cd+2 in wastewater by single particle ICP-MS

Vidmar, J., Oprčkal, P., Milačič, R., Mladenovič, A., Ščančar, J. Investigation of the behaviour of zero-valent iron nanoparticles and their interactions with Cd+2 in wastewater by single particle ICP-MS. Science of the Total Environment, 2018, 634, 1259-1268, doi: 10.1016/j.scitotenv.2018.04.081. 

Abstract: Zero-valent iron nanoparticles (nZVI) exhibit great potential for the removal of metal contaminants from wastewater. After their use, there is a risk that nZVI will remain dispersed in remediated water and represent potential nano-threats to the environment. Therefore, the behaviour of nZVI after remediation must be explored. To accomplish this, we optimised a novel method using single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) for the sizing and quantification of nZVI in wastewater matrices. H2 reaction gas was used in MS/MS mode for the sensitive and interference-free determination of low concentrations of nZVI with a low size limit of detection (36 nm). This method was applied to study the influence of different iron (Fe) loads (0.1, 0.25, 0.5 and 1.0 g L−1) and water matrices (Milli-Q water, synthetic and effluent wastewater) on the behaviour of nZVI, their interactions with Cd2+ and the efficiency of Cd2+ removal. The aggregation and sedimentation of nZVI increased with settling time. Sedimentation was slower in effluent wastewater than in Milli-Q water or synthetic wastewater. Consequently, Cd2+ was more efficiently (86%) removed from effluent wastewater than from synthetic wastewater (73%), while its removal from Milli-Q water was inefficient (19%). The trace amounts of Cd2+ that remained in the remediated water were either dissolved or sorbed to residual nZVI. The results of the nanoremediation of effluent wastewater with varying Fe loads showed that sedimentation was faster at higher initial concentrations of nZVI. After seven days of settling, low concentrations of Fe remained in the effluent wastewater at Fe loads of 0.5 g L−1 or higher, which could indicate that the use of nZVI in nanoremediation under the described conditions may not represent an environmental nano-threat. However, further studies are needed to assess the ecotoxicological impact of Fe-related NPs used for the nanoremediation of wastewaters.

Is the Kornati National Park still an acceptable reference area for environmental studies?

Ilenič, A., Lojen, S., Župan, I., Šarić, T., Šikić, Z., Vrhovnik, P., Dolenec, M. Is the Kornati National Park still an acceptable reference area for environmental studies? Geosciences, 2018, 8, 11, 1-12, doi: 10.3390/geosciences8110385. 

Abstract: The Kornati National Park (Croatia) is considered an environment with minimal anthropogenic input. The purpose of this study was to determine the isotopic characteristics of the sediment and muscle tissues of the banded dye-murex Hexaplex trunculus. We selected locations in the park according to their estimated risk of anthropogenic pollution (large, lower, and minimal). Isotopic analyses of the sedimentary organic carbon (δ¹³C_org values) showed that the sedimentary organic matter in locations with P. oceanica meadows (Piškera, Vrulje) was enriched in ¹³C compared to that of locations with the influx of terrestrial organic matter. The δ¹³C and δ¹⁵N values of the muscle tissues of H. trunuclus were the highest in the two locations with the highest possible anthropogenic impact (−14.47‰ and −15.66‰ for δ¹³C_org, +8.87‰ and +10.4‰ for δ¹⁵N). The high δvalues may indicate the presence of the pigment indirubin (C₁₆H₁₀O₂N₂) and other derivatives that cause the purple coloration but are also elevated because of the discharge of untreated sewage from a nearby marina and village.

Lead concentrations and stable lead isotope ratios in moss in Slovenia and Switzerland

Schnyder, E., Štrok, M., Kosonen, Z., Skudnik, M., Mazej, D., Jeran, Z., Thöni, L. Lead concentrations and stable lead isotope ratios in moss in Slovenia and Switzerland. Ecological Indicators, 2018, 95, 1, 250-259, doi: 10.1016/j.ecolind.2018.06.072. 

Abstract: Using moss as a biomonitor is an established technique for monitoring atmospheric deposition of trace elements, including lead (Pb), a metal that is toxic for most organisms. Lead enters the environment during production and combustion processes and during the use of leaded gasoline. There are four stable isotopes of Pb, and the isotopic composition can be used to determine sources and pathways of atmospheric Pb pollution.

Stable isotope analysis of major bioelements, multi-element profiling, and discriminant analysis for geographical origins of organically grown potato

Mahne Opatić, A., Nečemer, M., Budič, B., Lojen, S. Stable isotope analysis of major bioelements, multi-element profiling, and discriminant analysis for geographical origins of organically grown potato. Journal of Food Composition and Analysis, 2018, 71, 17-24, doi: 10.1016/j.jfca.2018.04.005.

Abstract:  The traceability of food products in terms of their geographical origins is getting more and more public attention. To be certain of the origin of organically grown potato (Solanum tuberosum L.), samples were subjected to stable isotope analysis of the major bioelements (δ13C, δ15N, δ18O, δ34S) and to element profiling (Na, Mg, P, S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn, Mo, Br, Rb, Sr), which included the rare earth elements (Sc, Y, Nb, La, Ce, Pr, Nd, Dy, Er). The present study was performed at the scale of Slovenia, which has diverse geographical characteristics. Using supervised pattern recognition statistical analysis (i.e., multivariate discriminant analysis), the characterisation and classification of organically grown potatoes were defined in terms of four Slovenian macro-regions: the Alpine, Dinaric, Mediterranean and Pannonian regions. The proposed model showed that 100% of the samples were correctly classified. However, an important prerequisite for official monitoring of the origin of a commodity is the availability of national and/or international databanks. As no databank exists for potato to date, the present study was performed to initiate the collection of data at the national level, to build a relevant and up-to-date databank. Once established, a reliable traceability model can be created.

Determination of hexavalent Cr in river sediments by speciated isotope dilution inductively coupled plasma mass spectrometry

Drinčić, A., Zuliani, T., Ščančar, J., Milačič, R. Determination of hexavalent Cr in river sediments by speciated isotope dilution inductively coupled plasma mass spectrometry. Science of the Total Environment, 2018, 637/638, 1286-1294, doi: 10.1016/j.scitotenv.2018.05.112. 

Abstract: During a sampling campaign in September 2015, elevated chromium (Cr) concentrations were observed in sediments of industrially exposed sites of the Sava River (stainless steel production and impact of metallurgic industry). To verify if sediments also contained hazardous hexavalent Cr (Cr(VI)), there was a need to develop a sensitive and reliable analytical procedure for its determination. In the determination of Cr(VI) in environmental samples, it is necessary to evaluate the suitability of the applied analytical methodology for each individual sample matrix. In these studies, the use of isotopically enriched Cr tracers importantly contribute to the validity of the obtained results. In the present work, an analytical procedure was optimised for the extraction of total Cr(VI) from sediments and the content of Cr(VI) determined by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). To leach the total amount of Cr(VI) from sediments, an ultrasound-assisted extraction procedure was applied at 80 °C, using 2% NaOH + 3% Na2CO3 as the extraction solution. The addition of 0.4 mol L−1 MgCl2 prevented oxidation of Cr(III) during the extraction step. To control for species interconversion and for an accurate calculation of Cr(VI) concentration by speciated isotope dilution (ID)-ICP-MS, the alkaline extract was doubly spiked with enriched 50Cr(VI) and 53Cr(III). The accuracy of the determination of Cr(VI) was verified by analysing the certified reference material CRM 041 (Cr(VI) in soil), and by spike recovery test. Low limits of detection (LOD) and quantification (LOQ) (1.25 and 4.0 μg Cr(VI) kg−1, respectively) and good repeatability of measurement (relative standard deviation better than ±4.8%) were obtained. The analytical data revealed that Cr(VI) concentrations in sediments of the Sava River did not represent any known environmental hazard.

Atmospheric and geogenic CO2 within the crown and root of spruce (Picea abies L. Karst.) growing in a mofette area

Vodnik, D., Thomalla, A., Ferlan, M., Levanič, T., Eler, K., Ogrinc, N., Wittmann, C., Pfanz, H. Atmospheric and geogenic CO2 within the crown and root of spruce (Picea abies L. Karst.) growing in a mofette area. Atmospheric Environment, 2018, 182, 286-295, doi: 10.1016/j.atmosenv.2018.03.043. 

Abstract: Mofettes are often investigated in ecology, either as extreme sites, natural analoguesto future conditions under climate change, or model ecosystems for environmental impact assessments of carbon capture and storage systems. Much of this research, however, inadequately addresses the complexity of the gas environment at these sites, mainly focusing on aboveground CO2-enrichment. In the current research, the gaseous environment of Norway spruce (Picea abies (L) Karst.) trees growing at the Stavešinske slepice mofette (NE Slovenia) were studied by measuring both soil([CO2]soil) and atmospheric CO2 concentrations ([CO2]air). Within the studied site (800 m2), soil CO2 enrichment was spatially heterogeneous; about 25% of the area was characterized by very high [CO2]soil (>40%) and hypoxic conditions. Aboveground gas measurements along vertical profiles not only revealed substantially elevated [CO2]air close to the ground (height up to 1.5 m), but also in the upper heights (20–25 m; crown layer). On the basis δ13C of CO2, it was shown that elevated CO2 relates to a geogenic source. Trees grown in high [CO2]soil were characterized by decreased radial growth; the δ13C of their wood was less negative than in trees growing in normal soil. Unfavorable gaseous soil conditions should generally be accepted as being by far the most important factor affecting (i.e. disturbing) the growth of mofette trees.

87Sr/86Sr isotope ratio and multielemental signatures as indicators of origin of European cured hams: the role of salt

Epova, E., Berail, S., Zuliani, T., Malherbe, J., Sarthou, L., Valiente, M., Donard, O. F. X. 87Sr/86Sr isotope ratio and multielemental signatures as indicators of origin of European cured hams: the role of salt. Food Chemistry, 2018, 246, 313-322, doi: 10.1016/j.foodchem.2017.10.143. 

Abstract: We have examined the potential of discriminant inorganic constituents (trace-, ultra-trace elements and Sr isotope ratios) to assess the origin of world famous brands of European dry-cured hams. The variation of the multielemental composition with principal component analysis allowed to discriminate the origin of Bayonne hams. Determined ratio 87Sr/86Sr was recognized as a strong additional distinctive parameter. The ratio 87Sr/86Sr allowed to better separate all the different categories of hams in addition to the multi-elemental detection. The major contribution of the value 87Sr/86Sr for the Bayonne ham is directly related to its curing due to the salt used in process coming from the nearby salt mine Salies-de-Béarn. Since the salt represents around 4% of the final product, it will therefore strongly influence the elemental and isotopic composition of hams. The overall discrimination potential of strontium isotope ratio is evidenced in the final statistical discrimination of the origin of hams.

Primary and secondary metabolites as a tool for differentiation of apple juice according to cultivar and geographical origin

Bat, K., Mozetič Vodopivec, B., Eler, K., Ogrinc, N., Mulič, I., Masuero, D., Vrhovšek, U. Primary and secondary metabolites as a tool for differentiation of apple juice according to cultivar and geographical origin. Lebensmittel-Wissenschaft + Technologie, 2018, 90, 238-245, doi: 10.1016/j.lwt.2017.12.026. 

Abstract: The presented study addresses the use of primary and secondary metabolites to differentiate apple juice according to the cultivar and geographical origin. Three apple cultivars were included: Idared and Golden Delicious from integrated/conventional agriculture practice and Topaz, which was produced organically from five different geographical regions in Slovenia: Alpine, Dinaric, Pannonian, Mediterranean and Submediterranean. Especially the minor phenolic compounds flavanols and flavonols, were confirmed as unambiguous and reliable markers of authentic apple juice for geographical origin differentiation including: flavanols (catechin, epicatechin, procyanidin B1 and procyanidin B2+B4); flavonols (quercetin-3-rhamnoside and quercetin-3-glucoside + quercetin-3-galactoside) and the levels of trans-piceid. The overall prediction ability was 60.9%, where only samples of apple juice from the Alpine region were sufficiently separated from the Mediterranean ones. Complete separation between three apple cultivars was achieved, when all the detected metabolites (with the exception of glucose and malic acid) were included in the Liner Discriminant Analysis (LDA).

Determination of geographical origin of commercial tomato through analysis of stable isotopes, elemental composition and chemical markers

Mahne Opatić, A., Nečemer, M., Lojen, S., Masten, J., Zlatić, E., Šircelj, H., Stopar, D., Vidrih, R. Determination of geographical origin of commercial tomato through analysis of stable isotopes, elemental composition and chemical markers. Food Control, 2018, 89, 133-141, doi: 10.1016/j.foodcont.2017.11.013. 

Abstract: In recent years, the geographical authentication of different agro-products, including vegetables, has gained an increasing amount of attention. This study investigated different approaches, both independently and in combination, to assign the country of origin to commercial tomato samples from Slovenia, Italy, Spain and Morocco. To create a model for their traceability, three sets of parameters were used: stable isotopes of the major bioelements (δ13C, δ15N, δ18O, δ34S), macro and micro elements (P, K, Ca, S, Cl, Zn, Br, Rb, Sr), and chemical markers (total antioxidant potential, total phenolic compounds, ascorbic acid, lutein, nitrates and nitrites, ammonium). The data obtained were analysed using the supervised pattern-recognition technique of multivariate discriminant analysis. The statistical analysis based on leave-one-out cross-validation revealed that the best overall success rate was achieved when using either the combination of all three sets of parameters, or only the elemental content data. In both cases, correct classification was obtained for 80% of the samples. Moreover, the present study highlights the first characterisation and classification of commercial tomato samples using the combination of the methodologies proposed.

Critical evaluation of the use of different nanoscale zero-valent iron particles for the treatment of effluent water from a small biological wastewater treatment plant

Oprčkal, P., Mladenovič, A., Vidmar, J., Mauko Pranjić, A., Milačič, R., Ščančar, J. Critical evaluation of the use of different nanoscale zero-valent iron particles for the treatment of effluent water from a small biological wastewater treatment plant. The Chemical Engineering Journal, 2017, 321, 20-30, doi: 10.1016/j.cej.2017.03.104. 

Abstract: Nanoremediation procedures are usually designed so that only one contaminant or similar class of contaminants is being considered. In the present work, a holistic approach was applied towards processes which simultaneously occur after the treatment of real effluent water from a small biological wastewater treatment plant (SBWTP) with different nanoscale zero-valent iron (nZVI) particles. Three different types of nZVI particles were tested: in-house nZVI, commercially available Nanofer STAR and Nanofer25 slurry, which differ in reactivity and their methods of synthesis. In order to optimise the conditions for the efficient removal of selected elements, nitrogen species, and pathogenic bacteria (Coliform bacteria, Escherichia coli, Intestinal Enterococci and Clostridium perfringens), effluent water samples were treated with different iron loads from each of the investigated nZVI at various mixing and settling times.

The results demonstrated that in-house nZVI, which is the most reactive of the nanoparticles tested, most effectively removed metals and inactivated pathogenic bacteria. However, the application of in-house nZVI is restricted, as it contaminates the remediated water with B, which originated from the reagents used in its synthesis. To a certain extent, all of the investigated types of nZVI reduced nitratesand nitrites to ammonium cations. The additional formation of ammonium nitrogen was the result of the interactions of the nZVI with the organic nitrogen present in the effluent water. At an optimised iron load, mixing time, and settling time, the most efficient removal of elements and disinfection of pathogens was achieved when Nanofer25 slurry was applied.

Development of an analytical method for the determination of polybrominated diphenyl ethers in mussels and fish by gas chromatography : inductively coupled plasma mass spectrometry

Novak, P., Zuliani, T., Milačič, R., Ščančar, J. Development of an analytical method for the determination of polybrominated diphenyl ethers in mussels and fish by gas chromatography : inductively coupled plasma mass spectrometry. Journal of Chromatography A, 2017, 1524, 179-187, doi: 10.1016/j.chroma.2017.09.059. 

Abstract: Six congeners of polybrominated diphenyl ethers (PBDEs): BDE 28, BDE 47, BDE 99, BDE 100, BDE 153 and BDE 154, were determined by a reliable and sensitive analytical method based on gas chromatography coupled to inductively coupled plasma mass spectrometry (GC-ICP-MS) in mussel and fish tissue samples. For their extraction, 30 min of ultrasound-assisted extraction with a 25% aqueous solution of tetramethylammonium hydroxide (TMAH) and an additional 2 h of mechanical shaking with tris(hydroxymethyl)aminomethane (Tris)-citrate buffer and iso-octane were applied. An effective cleaning, with minor solvent consumption, was achieved by passing the extract through a column filled with Florisil. PBDEs in the organic phase were quantified by GC-ICP-MS. Accuracy checks were performed by analyzing reference materials NIST SRM 2974a (freeze-dried mussel tissue) and SRM 1946 (fresh fish tissue homogenate) samples with a standard addition calibration method and by comparative analysis with species-specific isotope-dilution GC-ICP-MS. Good agreement of results between the determined and certified values were obtained (recoveries lied between 94 and 105%). Limits of detection (LODs) expressed on wet weight (ww) basis were 0.003 ng g−1 for BDE 28, 0.006 ng g−1 for BDE 47, 0.008 ng g−1 for BDE 99, 0.004 ng g−1 for BDE100, 0.005 ng g−1 for BDE 153 and 0.009 ng g−1 for BDE 154. The analytical method was applied for the determination of PBDEs in marine mussels and fish samples from the northern Adriatic Sea and fish samples from the Sava River. Among the six PBDEs congeners determined, BDE 47, BDE 100 and BDE 99 were commonly detected in the samples analysed.

Geographical origin characterization of Slovenian garlic using stable isotope and elemental composition analyses

Mahne Opatić, A., Nečemer, M., Kocman, D., Lojen, S. Geographical origin characterization of Slovenian garlic using stable isotope and elemental composition analyses. Acta Chimica Slovenica, 2017, 64 (4), 1048-1055, doi: 10.17344/acsi.2017.3476.

Abstract: In the present research, the applicability of stable isotope (δ13C, δ15N, δ34S, δ18O) and multi-element (P, S, Cl, K, Ca, Si, Zn, Br, Rb, Sr) data for determining the geographical origin of garlic (Allium sativum L.) at the scale of Slovenia was examined within the framework of EU “ISO-FOOD” project for food quality, safety and traceability. Slovenia is a rather small country (20273 km2) with significant geological and biological diversity. Garlic, valued for its medicinal properties, was collected from Slovenian farms with certified organic production and analyzed by Elemental Analyzer Isotope Ratio Mass Spectrometry combined with Energy Dispersive X- ray Fluorescence Spectrometry. Multivariate discriminant analysis, revealed a distinction between four Slovenian macro-regions: Alpine, Dinaric, Mediterranean and Pannonian. The model was validated through a leave-10%, 20% and 25% out cross validation. The overall success rate of correctly reclassified samples was 77% (on average), indicating that the model and the proposed methodology could be a promising tool for rapid, inexpensive and robust screening to control the provenance of garlic samples.

Simultaneous speciation of chromate, arsenate, molybdate and vanadate in alkaline samples by HPLC-ICP-MS at different concentration levels of vanadate

Drinčić, A., Ščančar, J., Zuliani, T., Nikolić, I., Milačič, R. Simultaneous speciation of chromate, arsenate, molybdate and vanadate in alkaline samples by HPLC-ICP-MS at different concentration levels of vanadate. Journal of Analytical Atomic Spectrometry, 2017, 32 (11), 2200-2209, doi: 10.1039/C7JA00273D. 

Abstract: Flay ash, cement and electric arc furnace (EAF) dust are frequently mixed in building composites. From them, chromium (Cr), arsenic (As), molybdenum (Mo) and vanadium (V) may be leached. Concentrations of V in leachates may be significantly higher than those of Cr, As and Mo, making simultaneous speciation analysis particularly difficult. In this work, a high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) procedure was used for simultaneous speciation of chromate, arsenate, molybdate and vanadate. First, the behaviour of Cr, As, Mo and V species in different oxidation states was studied during their separation under acidic (pH 5) and alkaline (pH 12) conditions. At alkaline pHs chromate, arsenate, molybdate and vanadate were simultaneously separated and eluted at retention times from 390 to 450 s, 230 to 270 s, 340 to 430 s and 270 to 380 s, respectively and detected on-line by ICP-MS, recording m/z 52, 75, 95 and 51, respectively. When V species were leached in significantly higher concentrations than Cr, Mo and As, their detection was possible at the low abundance (0.25%) 50V isotope, which is also the mass of the 50Cr isotope (abundance 4.345%), due to selective separation between V and Cr species. Good repeatability of measurement (RSD better than ±3.0%) and quantitative elution of elemental species (column recoveries 99–105%) were obtained. Finally, the procedure was applied in the simultaneous speciation analysis of chromate, arsenate, molybdate and vanadate in highly alkaline aqueous leachates from composites consisting of fly ash, cement and EAF dust that contained a wide range of concentrations of vanadate.

Potentially toxic elements in water and sediments of the Sava River under extreme flow events

Milačič, R., Zuliani, T., Vidmar, J., Oprčkal, P., Ščančar, J. Potentially toxic elements in water and sediments of the Sava River under extreme flow events. Science of the Total Environment, 2017, 605/606, 894-905, doi: 10.1016/j.scitotenv.2017.06.260. 

Abstract: River ecosystems are exposed to various stressors. Among them, elements may contribute to overall pollution of riverine environments, in particular during the extreme flow events. To evaluate the influence of variable river flow conditions on the mobilization of potentially toxic elements (PTE) (Cr, Ni, Cd, Zn, Pb, As and Cu) from sediments into the overlaying waters of the Sava River, samples were collected in September 2014, during extremely high water discharges and in September 2015, under low water discharge conditions. In water samples the total element concentrations and the dissolved element contents (< 0.45 μm) were determined. Sediment pollution was estimated by determination of the total element concentrations and mobile element fraction (0.11 mol L− 1 acetic acid). Anthropogenic inputs of elements to sediments were evaluated by normalizing elemental against Al concentration. The results showed that concentrations of PTE in water were in general higher during high water discharges, while the soluble concentrations were higher during low water level conditions. Concentrations of PTE in the Sava sediments collected in 2015 were lower than those collected in 2014, mainly because during the extreme floods a mixture of bank sediment material and contaminated soil was sampled. Partitioning coefficients between suspended particulate matter (SPM) and soluble content of elements in the water under high and low flow conditions, indicated on different affinity of elements to SPM in relation to different flow regimes. The potential ecological risk posed by the simultaneous presence of PET in sediments was evaluated by Probable Effect Concentration Coefficient (PEC-Q) approach. Under high water level conditions, PEC-Qs were all above critical value 0.34 and derived mostly from anthropogenic inputs of Cr and Ni. Overall sediment toxicity was much lower under low water discharges. The data from this study importantly contribute to the knowledge regarding the behaviour of PTE under extreme flow events.

Sizing and simultaneous quantification of nanoscale titanium dioxide and a dissolved titanium form by single particle inductively coupled plasma mass spectrometry

Vidmar, J., Milačič, R., Ščančar, J. Sizing and simultaneous quantification of nanoscale titanium dioxide and a dissolved titanium form by single particle inductively coupled plasma mass spectrometry. Microchemical Journal, 2017, 132, 391-400, doi: 10.1016/j.microc.2017.02.030. 

Abstract: As a consequence of their widespread use, titanium dioxide nanoparticles (TiO2NPs) have been released into the environment where they can act as stressors towards biota. For the assessment of the environmental impact of these NPs it is important to quantitatively determine their concentration, size distribution and the dissolved Ti fraction in different water samples. In the present work, a new analytical approach was applied for sizing and quantitative determination of TiO2NPs (anatase and rutile) and dissolved Ti in aqueous samples by the use of single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). The accuracy of the quantification of TiO2NPs by SP-ICP-MS was verified by calculating the recoveries between the determined and expected Ti concentrations (90–100%). The size distributions of TiO2NPs calculated by SP-ICP-MS (108 ± 10 nm for rutile, 29 ± 2 nm for anatase) were in a good agreement with data obtained by TEM (96–106 nm for rutile, 21–38 nm for anatase) and DLS (117 ± 22 nm for rutile, 42 ± 30 nm for anatase). The influence of different dwell times on the sizing and quantification of nanoscale titanium dioxide was also examined. Low limits of detection for NP diameter (37 nm) and NP concentration (3.69 × 10− 3 ng Ti mL− 1 for rutile and 0.058 × 10− 3 ng Ti mL− 1 for anatase) were obtained. In order to apply the procedure developed for the sizing and quantification of TiO2NPs in environmental waters, the severe Ca isobaric interference at m/z 48 was overcome by measuring the Ti on m/z 47. It was demonstrated that the procedure optimized for the determination of Ti in environmental waters can be applied in the sizing and quantification of TiO2NPs in river water samples spiked with nanoscale anatase and rutile.

Nickel speciation in cocoa infusions using monolithic chromatography: post-column ID-ICP-MS and Q-TOF-MS

Peeters, K., Zuliani, T., Žigon, D., Milačič, R., Ščančar, J. Nickel speciation in cocoa infusions using monolithic chromatography: post-column ID-ICP-MS and Q-TOF-MS. Food Chemistry, 2017, 230, 327-335, doi: 10.1016/j.foodchem.2017.03.050. 

Abstract: Nickel (Ni) is considered to be a potentially harmful element for humans. Its levels in foodstuffs are normally low (below 0.2mgkg-1), but sensitive individuals may develop allergy to Ni as a result of dietary consumption. Cocoa contains relatively high Ni concentrations (around 3mgkg-1). Ni bioavailability, its role in the flavour of food and its potential impact on human health depends primarily on its chemical species. However, there is a lack of information about Ni speciation in cocoa. In this work Ni species were separated on a weak convective interaction media diethylamine (CIM DEAE) monolithic chromatographic column and quantified by the post-column isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). The Ni binding ligands in the separated fractions were identified "off line" by quadrupole time-of-flight mass spectrometry (Q-TOF MS). Ni was found to be present in the cocoa infusions as Ni2+ and Ni-gluconate and Ni-citrate complexes

Stable isotope ratio and elemental composition parameters in combination with discriminant analysis classification model to assign country of origin to commercial vegetables: a preliminary study

Mahne Opatić, A., Nečemer, M., Lojen, S., Vidrih, R. Stable isotope ratio and elemental composition parameters in combination with discriminant analysis classification model to assign country of origin to commercial vegetables: a preliminary study. Food Control, 2017, 80, 252-258, doi: 10.1016/j.foodcont.2017.05.010. 

Abstract: Recently, increased public attention has been paid to the geographical authentication of food, including vegetables, which are considered to be one of the major health-promoting components in a balanced diet. The purpose of the present study was to investigate the suitability of the use of isotopic compositions of light elements (δ13C, δ15N, δ18O, δ34S) in combination with multi-elemental fingerprinting (P, S, Cl, K, Ca, Mn, Fe, Zn, Br, Rb, Sr) to provide rapid, robust and inexpensive screening methods for distinguishing lettuce, sweet pepper, and tomato samples according to their given country of origin (i.e., Slovenia, Austria, Spain, Morocco, Italy, Greece), and thus ensuring their traceability in terms of their authenticity. The classification efficiency of the proposed multivariate statistical models using supervised pattern-recognition analysis, namely multivariate discriminant analysis, was sufficient for rapid and robust screening purpose. The predictions of the suggested discriminant analysis models per kind using cross-validation leave-one-out were 86.2%, 71.1% and 74.4% for lettuce, sweet pepper and tomato, respectively. The first use of the proposed methodology on vegetable samples on European and Mediterranean scales provides a valuable and necessary contribution to the development and implementation of a new national surveillance system that can be used to trace the geographical origins of vegetables.