Geochemistry and origin of inorganic contaminants in soil, river sediment and surface water in a heavily urbanized river basin

Understanding the geochemistry and contamination of rivers affected by anthropogenic activities is paramount to water resources management. The Asopos river basin in central Greece is facing environmental quality deterioration threats due to industrial, urban and agricultural activities. Here, the geochemistry of river sediments and adjacent soil in terms of major and trace elements (Al, Ca, Mg, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and the geochemical composition of surface water in terms of major ions, trace elements and nutrients along the Asopos river basin were determined. In addition, this study characterized potential nitrate sources through the analysis of stable isotope composition of NO3- (δ15Ν-ΝΟ3- and δ18Ο-ΝΟ3-). Results indicated that specific chemical constituents including nutrients (NO2-, NH4+, PO43-) and major ions (Na+, Cl-) were highest in the urban, industrialized and downstream areas. On the other hand, nitrate (NO3-) concentration in river water (median 7.9 mg/L) showed a decreasing trend from the upstream agricultural sites to the urban area and even more in the downstream of the urban area sites. Ionic ratios (NO3-/Cl-) and δ15Ν-ΝΟ3- values (range from +10.2 ‰ to +15.7 ‰), complemented with a Bayesian isotope mixing model, clearly showed the influence of organic wastes from septic systems and industries operating in the urban area on river nitrate geochemistry. The interpretation of geochemical data of soil and river sediment samples demonstrated the strong influence of local geology on Cr, Fe, Mn and Ni content, with isolated samples showing elevated concentrations of Cd, Cu, Pb and Zn, mostly within the industrialized urban environment. The calculation of enrichment factors based on the national background concentrations provided limited insights into the origin of geogenic metals. Overall, this study highlighted the need for a more holistic approach to assess the impact of the geological background and anthropogenic activities on river waters and sediments.

Circulating Copper Is Associated with Inflammatory Biomarkers in Greek Older Adults with Osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis, that causes a significant decrease in the quality of life of the afflicted and constitutes a great burden for the socioeconomic system. Trace elements and heavy metals are implicated in the pathophysiology of OA, exacerbating inflammatory and oxidative stress responses. The aim of this cross-sectional study was to quantify metals in plasma samples of Greek OA patients and explore their link with disease related parameters, health status or quality of life, as well as epigenetic OA markers. This is the first study on plasma metal levels in Greek knee OA patients. To achieve precision in plasma metal and miRNA measurements, high-quality samples were selected from a subset of 34 participants (NCT04783792). Demographic, quality of life, clinical, biochemical, inflammation, oxidative stress, and anthropometric parameters, as well as microRNA levels were assessed. Significant correlations were found between circulating metals with OA related parameters or with measured microRNAs. Also, significant positive associations between plasma copper (Cu) levels and CRP (p = 0.033) or IL-6 (p = 0.001) occurred when adjusting for age, gender, BMI, physical activity level, smoking, disease severity, total arthroplasty, and dietary intake of the respective metal. Cu's role in OA is bidirectional, and this study confirms the findings that in OA, Cu is positively associated with inflammation. Such relationships between lifestyle, environment and OA enhance our understanding and encourage further study on metals related to OA inflammation.

Use of Unmanned Surface Vehicles (USVs) in Water Chemistry Studies

Unmanned surface vehicles (USVs) equipped with integrated sensors are a tool valuable to several monitoring strategies, offering enhanced temporal and spatial coverage over specific timeframes, allowing for targeted examination of sites or events of interest. The elaboration of environmental monitoring programs has relied so far on periodic spot sampling at specific locations, followed by laboratory analysis, aiming at the evaluation of water quality at a catchment scale. For this purpose, automatic telemetric stations for specific parameters have been installed by the Institute of Marine Biological Resources and Inland Waters of Hellenic Centre for Marine Research (IMBRIW-HCMR) within several Greek rivers and lakes, providing continuous and temporal monitoring possibilities. In the present work, USVs were deployed by the Athens Water and Sewerage Company (EYDAP) as a cost-effective tool for the environmental monitoring of surface water bodies of interest, with emphasis on the spatial fluctuations of chlorophyll α, electrical conductivity, dissolved oxygen and pH, observed in Koumoundourou Lake and the rivers Acheloos, Asopos and Kifissos. The effectiveness of an innovative heavy metal (HM) system installed in the USV for the in situ measurements of copper and lead was also evaluated herewith. The results obtained demonstrate the advantages of USVs, setting the base for their application in real-time monitoring of chemical parameters including metals. Simultaneously, the requirements for accuracy and sensitivity improvement of HM sensors were noted, in order to permit full exploitation of USVs' capacities.

Vanadium, cobalt, zinc, and rubidium are associated with markers of inflammation and oxidative stress in a Greek population with obesity

Introduction

The prevalence of obesity is rising globally, with negative effects on the socioeconomic system. As a result of its drivers which include low-grade chronic inflammation, oxidative stress, and fatty acid metabolism, this phenotype develops metabolic anomalies that exacerbate its pathogenesis. It has been discovered that metals and metalloids have substantial effects on both the immune system and metabolism and are influenced by factors connected to obesity. Although there is a known connection between metals, obesity, and related metabolic disorders, it is still under research.

Methods

We determined the plasma levels of 16 metals and metalloids in 76 individuals with obesity and investigated the relationships with inflammatory and oxidative stress biomarkers in order to clarify the processes by which metals/metalloids exhibit their effects.

Results

After adjusting for age, gender, BMI, physical activity level, smoking, the existence of metabolic abnormalities, and dietary intake of the corresponding metal, regression analysis revealed the following statistically significant associations; vanadium was negatively associated with oxLDL (Beta ± SE= -0.014 ± 0.005, p=0.007), zinc was negatively associated with leptin (Beta ± SE= -12.390 ± 5.226, p=0.025), cobalt was associated negatively with adiponectin (Beta ± SE= -0.030 ± 0.012, p=0.001) and positively with MPO (Beta ± SE= 0.002 ± 0.001, p=0.023), and rubidium was negatively associated with oxLDL (Beta ± SE= -1.139 ± 0.411, p=0.008) and positively with MPO (Beta ± SE= 0.324 ± 0.102, p=0.003).

Discussion

The aforementioned associations highlight the need for further research, demonstrating the importance of inflammation and oxidative stress in the association between metals/metalloids and obesity-related metabolic abnormalities.

Artemisia arborescens and Artemisia inculta from Crete; Secondary Metabolites, Trace Metals and In Vitro Antioxidant Activities

BACKGROUND

Currently, the use of medicinal plants has increased. Artemisia species have been used in several applications, including medicinal use and uses in cosmetics, foods and beverages. Artemisia arborescens L. and Artemisia inculta are part of the Mediterranean diet in the form of aqueous infusions. Herein, we aimed to compare the secondary metabolites of the decoctions and two different extracts (methanolic and aqueous-glycerolic) of these two species, as well as their antioxidant capacity and trace metal levels.

METHODS

Total phenolic, total flavonoid, total terpenes, total hydroxycinnamate, total flavonol, total anthocyanin contents and antioxidant/antiradical activity were determined, and GC/MS analysis was applied to identify and quantify phenolics and terpenoids. Trace metals were quantified with ICP-MS.

RESULTS

Aqueous-glycerolic extracts demonstrated higher levels of total secondary metabolites, greater antioxidant potential and higher terpenoid levels than decoctions and methanolic extracts. Subsequently, the aqueous-glycerolic extract of a particularly high phenolic content was further analyzed applying targeted LC-MS/MS as the most appropriate analytic tool for the determination of the phenolic profile. Overall, twenty-two metabolites were identified. The potential contribution of infusions consumption to metal intake was additionally evaluated, and did not exceed the recommended daily intake.

CONCLUSIONS

Our results support the use of these two species in several food, cosmetic or pharmaceutical applications.

Assessment of natural and anthropogenic contamination sources in a Mediterranean aquifer by combining hydrochemical and stable isotope techniques

The Atalanti basin is an intensively cultivated area in central Greece, facing groundwater quality deterioration threats due to natural and anthropogenic-related contamination sources. A combination of statistical and hydrogeochemical techniques, and stable isotope compositions (δ²H-H₂O and δ¹⁸Ο-Η₂Ο, δ¹⁵Ν-ΝΟ₃^- and δ¹⁸Ο-ΝΟ₃^-, δ³⁴S-SO₄^2- and δ¹⁸O-SO₄^2-) were applied to elucidate the origin of salinity and nitrate contamination, and shed light on the potential associations between geogenic Cr(VI) and NO₃^- sources and transformations. Nitrate and Cr(VI) concentrations reached up to 337 mg L^-1 and 76.1 μg L^-1, respectively, exceeding WHO threshold values in places. The cluster of samples with the high salinity was mostly influenced by irrigation return flow and marine aerosols, and less by seawater intrusion, as evidenced by the ionic ratios (e.g., Na⁺/Cl^-) and the stable isotopes of oxygen and hydrogen in water, and sulphur and oxygen in sulphates. The δ¹⁵Ν-ΝΟ₃^- and δ¹⁸O-NO₃^- values ranged from +2.0 ‰ to +14.5 ‰ and + 0.3 ‰ to +11.0 ‰, respectively. We found that the dominant sources of NO₃^- in groundwater were fertilizers in the central part of the area and sewage waste in the northern part around the residential area of Livanates. The occurrence of denitrification was evident in the northern part of the basin, where the DO levels were lowest (≤ 2.2 mg L^-1), whereas nitrification of NH₄⁺-fertilizers prevailed in the central part. Elevated Cr(VI) values (≥ 20 μg/l) were associated with the lowest deviation of the measured from the theoretical nitrification δ¹⁸Ο-NO₃^- values, whereas the lowest Cr(VI) values were observed in the denitrified water samples. Our isotope findings revealed the strong influence of redox conditions on the biogeochemical transformations of N species and the mobilization of Cr(VI) that will help improve the understanding of the fate of these contaminants from the unsaturated zone to the groundwater in areas of agricultural and urban land use.

Clinical and inflammatory biomarkers of inflammatory bowel diseases are linked to plasma trace elements and toxic metals; new insights into an old concept

Background

Inflammatory bowel diseases (IBD) are chronic immune-mediated diseases, mainly represented by Crohn's disease (CD) and ulcerative colitis (UC). Several environmental factors have been proposed to contribute to disease pathogenesis, amongst which are metals. These can affect the immune system and may be associated with IBD. The aim of the present cross-sectional study was to investigate blood levels of metals in IBD patients and to examine possible associations with clinical and inflammatory disease markers.

Methods

In total, 76 CD patients, 39 UC patients and 38 healthy controls were included. Blood and stool samples were collected. Metals were quantified in plasma samples using inductively coupled plasma mass spectrometry.

Results

There were more abnormalities of circulating metals in CD than in UC when compared to healthy controls. CD: Concentrations of the essential trace elements zinc and selenium were lower in CD patients than the controls. Chromium was negatively associated with serum IL-6 (Beta: -3.558, p = 0.011), and caesium with fecal calprotectin (Beta: -0.481, p = 0.038) and serum IL-10 (Beta: -1.912, p = 0.050). In contrast, copper was positively associated with C-reactive protein (Beta: 2.548 × 10², p = 0.033). UC: In UC, a negative association of iron with serum myeloperoxidase levels (Beta: -1.270 × 10³, p = 0.044) was detected. Thallium, a hazardous metal, however, was positively associated with disease activity (Beta: 3.899, p = < 0.01).

Conclusion

In conclusion, our study offers new insights into the relations of metals with IBD. Further research should focus on the evaluation of the above associations and potential underlying mechanisms.

Human serum elements' levels and leukemia: A first pilot study from an adult Greek cohort

BACKGROUND

The present study focuses on the evaluation of potential relationships between trace elements and acute and chronic types of leukemia, via the determination of their levels in human blood serum.

METHODS

A total of 199 serum samples from a Greek cohort were examined, including both leukemia cases and controls. Elements' analysis was carried out using inductively coupled plasma mass spectrometry (ICP-MS) and demographic features such as age, gender, smoking habits and area of residence were recorded and statistically treated applying Shapiro-Wilk, Kolmogorov-Smirnov, Mann Whitney and Kruskal Wallis tests (p < 0.05). Spearman correlation and principal component analysis (PCA) were also performed to investigate possible associations.

RESULTS

The results demonstrated significantly higher (p < 0.05) trace elements concentrations in cases' serum compared to that of controls excluding Ba, with Cu (median concentration 1295 μg L^-1) being the most abundant in cases. Additionally, concentration of toxic Pb and Cd were found at seven and four fold higher concentrations in cases, respectively. Among the trace elements examined, only Rb (164 μg L^-1) was detected in higher concentrations in controls. Ba, Cd and Co presented the lowest concentrations (lower than 1 μg L^-1). PCA was performed for overall and classified data, indicating a stronger relation among the toxic As, Cd, Ni and Pb in cases than controls, particularly referring to smokers and industrial sites' residents. Hematological parameters and factors such as age and gender did not present any significant outcome or correlation.

CONCLUSIONS

The findings from this pilot study suggest a potential relationship between metals and leukemia, especially concerning the toxic ones. Results from the employed source apportionment tools imply that smoking and atmospheric degradation may be positively related with higher metal serum levels in leukemia patients.

Trace metals accumulation in the eco-system water - soil - vegetation (Agropyron cristatum) - common voles (Microtus arvalis) - parasites (Hymenolepis diminuta) in Radnevo region, Bulgaria

BACKGROUND

Coal and coal processing industries provoke trace metal pollution, which has a negative effect on the water - soil - vegetation - small mammals eco-system, constituting part of the food chain and exerting a serious impact on human health.

OBJECTIVES

Assessment of the environmental impact of Maritza iztok coal complex, situated east of Radnevo town, Bulgaria, by tracking the dynamics and accumulation of trace metals in the eco-system water - soil - vegetation - common voles - parasites.

METHODS

Samples from surface waters, their nearby uncultivated soils, meadow uncultivated vegetation (Agropyron cristatum) and field common voles (Microtus arvalis) were collected. In situ measurements and laboratory extraction procedures and analyses were performed. Accumulation and mobility indices were calculated. The distribution of dissolved Mn, Ni, Cu, Zn and Pb chemical species in water-soil extracts was calculated using a thermodynamic approach. Two thermodynamic models were applied - the classical ion-association model for calculating the inorganic trace metal species and the Stockholm Humic Model (SHM) accounting for the complexation reactions of trace metals with organic matter. Visual Minteq computer program, Version 3.1 was used. The relationship chemical species - bioaccumulation was discussed.

RESULTS

Pb and Mn, together with SO₄^2- and PO₄^3- were found to be the main pollutants of waters in the region. The soils studied exhibited low concentrations of trace metals, not exceeding the specified MACs. The content of Mn was the highest, followed by Zn, Pb, Cu and Ni. The highest phytoaccumulation coefficients in the studied uncultivated grass vegetation were calculated for Cu and Zn, being 1-2 orders of magnitude higher than those of Mn and Ni. The accumulation of trace metals was explained on the basis of ions mobility and chemical species distribution. In the case of the host-parasite system Microtus alvaris - Hymenolepis diminuta, Zn displays the highest accumulation coefficient, followed by those of Cu and Pb. The parasite showed a higher bioaccumulation compared to infected common voles, with the highest bioaccumulation found for Ni.

CONCLUSIONS

The bioaccumulation of trace metals depends on their mobility, concentration and chemical forms in water-soil solutions. Metal-organic species stimulate the phytoaccumulation of trace metals while inorganic ones suppress it. The sequence of trace metals bioaccumulation in common voles is analogous to that of soil contamination. The parasite exhibited higher bioaccumulation levels compared to infected common voles.

Modelling of chemical species of Al, Mn, Zn, and Pb in river body waters of industrial areas of West Rhodope Mountain, Bulgaria

The assessment of the ecological status of natural surface water, in terms of dominant trace metals, within an area subject to various sources of pollution including a non-ferrous metal ore mining, such as the West Rhodope Mountain, Bulgaria, is significant. The present study estimates the ecological status of river body waters at industrial areas of the West Rhodope Mountain, Bulgaria, simultaneously evaluating the possibility of state forecasting, together with assessing the potential risks, through the study of scenarios focusing on (i) possible variations of physicochemical parameters such as pH, concentration levels of trace metals, sulphates, and dissolved organic carbon (DOC) of surface water and (ii) consideration of potential spontaneous precipitation reactions in the studied waters. The ecological status of river body waters was assessed through a combination of experimental field, laboratory, and computational techniques. Al, Mn, Zn, and Pb were found to be the dominant pollutants with a variety of chemical species and distribution. The most significant difference characterizing the chemical species distribution in light of total spontaneous crystallization in the systems was found for Pb, followed by Zn and Mn, with the differences being more significant at lower trace metal levels. The calculated species were discussed on the basis of HSAB (hard and soft acids and bases) principle.

Heart Failure and PAHs, OHPAHs, and Trace Elements Levels in Human Serum: Results from a Preliminary Pilot Study in Greek Population and the Possible Impact of Air Pollution

Cardiovascular diseases (CVDs) have been associated with environmental pollutants. The scope of this study is to assess any potential relation of polycyclic aromatic hydrocarbons (PAHs), their hydroxylated derivatives, and trace elements with heart failure via their direct determination in human serum of Greek citizens residing in different areas. Therefore, we analyzed 131 samples including cases (heart failure patients) and controls (healthy donors), and the respective demographic data were collected. Significantly higher concentrations (p < 0.05) were observed in cases' serum regarding most of the examined PAHs and their derivatives with phenanthrene, fluorene, and fluoranthene being the most abundant (median of >50 μg L-1). Among the examined trace elements, As, Cd, Cu, Hg, Ni, and Pb were measured at statistically higher concentrations (p < 0.05) in cases' samples, with only Cr being significantly higher in controls. The potential impact of environmental factors such as smoking and area of residence has been evaluated. Specific PAHs and trace elements could be possibly related with heart failure development. Atmospheric degradation and smoking habit appeared to have a significant impact on the analytes' serum concentrations. PCA-logistic regression analysis could possibly reveal common mechanisms among the analytes enhancing the hypothesis that they may pose a significant risk for CVD development.

Evaluation of Polyurea-Crosslinked Alginate Aerogels for Seawater Decontamination

Polyurea-crosslinked Ca-alginate (X-Ca-alginate) aerogel beads (diameter: 3.3 mm) were evaluated as adsorbents of metal ions, organic solvents, and oils. They were prepared via reaction of an aromatic triisocyanate (Desmodur RE) with pre-formed Ca-alginate wet gels and consisted of 54% polyurea and 2% calcium. X-Ca-alginate aerogels are hydrophobic nanoporous materials (90% v/v porosity), with a high BET surface area (459 m²/g⁻¹), and adsorb Pb^II not only from ultrapure water (29 mg/g⁻¹) but also from seawater (13 mg/g⁻¹) with high selectivity. The adsorption mechanism involves replacement of Ca^II by Pb^II ions coordinated to the carboxylate groups of the alginate backbone. After treatment with a Na₂EDTA solution, the beads can be reused, without significant loss of activity for at least two times. X-Ca-alginate aerogels can also uptake organic solvents and oil from seawater; the volume of the adsorbate can be as high as the total pore volume of the aerogel (6.0 mL/g⁻¹), and the absorption is complete within seconds. X-Ca alginate aerogels are suitable for the decontamination of aquatic environments from a broader range of inorganic and organic pollutants.

A DPSIR Approach to Selected Cr(VI) Impacted Groundwater Bodies of Central Greece

The holistic approach of Driver-Pressure-State-Impact-Response (DPSIR) methodology was applied to selected Cr(VI) impacted groundwater bodies of Central Greece. The main driving forces in the study areas are agricultural activities, urban and industrial development as well as tourism. The main pressures induced by the anthropogenic activities are fertilizer use, uncontrolled urban sewage disposal and industrial effluents discharges. Groundwater stress is caused by the qualitative degradation due to Cr(VI), NO₃^-, Cl^- and SO₄^2- contamination. Hexavalent chromium occurrence is attributed to both geogenic and anthropogenic sources. The maximum Cr(VI) concentration (11.7 mg/L) was measured in Oinofyta area. Important impacts are the deterioration of groundwater body chemical status as well as the decline of groundwater use efficiency. Based on the applied DPSIR, a management framework is proposed in order to address the complex environmental issue of Cr(VI) in the study areas.

Trace elements, polycyclic aromatic hydrocarbons, mineral composition, and FT-IR characterization of unrefined sea and rock salts: environmental interactions

Unrefined sea salt originates from seawater, typically by natural evaporation. Being minimally processed, it contains the natural minerals and impurities of seawater. Despite the wide applications of salt for culinary and food preservation purposes, the available composition data is particularly limited. Since seawater often contains various harmful substances at a trace or ultra-trace level, their determination in unrefined salt is significant in terms of quality control and food safety. Twenty-four (24) samples of unrefined sea and rock salts retailed in Greece were studied in terms of their trace metals and polycyclic aromatic hydrocarbon (PAH) content, which constitute the usual pollutants examined in seawater. In addition, samples' color and mineralogy were recorded and their attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectra were obtained. No statistically significant differences were found between sea and rock salts regarding their trace metal (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) content (excluding V) and the 15 PAHs examined. ATR FT-IR succeeded to discriminate among sea, rock, flower, and underground salty water salts. Compared with the typical trace metal concentrations in seawater, quite high Pb values were determined in both sea and rock salts, whereas outliers in the rest of the trace elements examined were scarce. Median values of the sum of PAH (ΣPAHs) concentrations were calculated equal to 2.1 and 2.6 ng g^-1 for sea and rock salts, respectively. Environmental interactions of salt production with trace elements and PAHs are also discussed.

Dynamics of trace metals in the system water - soil - plant - wild rats - tapeworms (Hymenolepis diminuta) in Maglizh area, Bulgaria

BACKGROUND

The impact of chemical elements on the biosphere is a function of their concentration and chemical form. Elucidation and prognosing of the latters in water basins and soil extracts is of particular significance for the assessment of their bioaccumulation in plants and animals.

OBJECTIVES

Trace metals dynamics in the system water - soil-plant-wild rats - Hymenolepis diminuta in two agro-industrial zones (East and West) around Maglizh city, Bulgaria were investigated through experimental studies and thermodynamic modelling of the chemical species.

METHODS

Samples from surface waters of rivers, their nearby uncultivated soils, meadow uncultivated vegetation (Ranunculus acris and Gramineae) and field rats were collected. In situ measurements and laboratory analyses were performed for the determination of the physico-chemical characteristics and total concentrations of Al, Fe, Mn, Ni, Cu, Zn and Pb. The distribution of their dissolved chemical species in water samples and in the aqueous soil extracts was calculated using a thermodynamic approach. The relationship chemical species - bioaccumulation was discussed.

RESULTS

Waters and soils in the East zone of Maglizh area were found to be more polluted compared to those in the West one, regarding Ni, Mn, Zn, Pb and Cu, while Mn and Cu displayed the highest mobility in West zone soils. Trace metals contents in Ranunculus acris exceed that in Gramineae, since the highest accumulation factors were calculated for Cu and Zn. The highest accumulation in rats was found for Zn followed by Cu, being higher in the West zone. Thermodynamic modelling shows that Mn²⁺ free ions are dominant in both waters and aqueous soil extracts. Ni²⁺ and Zn²⁺ ions followed by metal-organic complexes are dominant in waters of East zone while metal-organic complexes followed by free ions are dominant in waters of West zone and both soil extracts. Metal-organic complexes are dominant for Fe, Cu and Pb in all samples studied, while mainly hydroxy forms (Al(OH)₄^-) followed by metal-organic complexes are typically for Al depending on pH.

CONCLUSIONS

Experimentally established bioaccumulation of trace metals in the studied vegetation and rats is a consequence of the total concentration of trace metals in waters and soils, their mobility and chemical species. The dominance of organic complexes of trace metals is a prerequisite for their bioaccumulation in plants. Rats are in direct contact with the soil solution and therefore, of importance is the content of free ions of Mn²⁺, Ni²⁺, Zn²⁺, which are easily absorbed through the skin. The host-helminth system wild rat/H. diminuta could be used as a bioindicator for trace metals pollution.

Copper Complexing Capacity and Trace Metal Content in Common and Balsamic Vinegars: Impact of Organic Matter

Complex formation is among the mechanisms affecting metal bioaccessibility. Hence, the quantification of organic metal complexation in food items is of interest. Organic ligands in solutions of environmental and/or food origin function as buffering agents against small changes in dissolved metal concentrations, being able to maintain free metal ion concentrations below the toxicity threshold. Organic matter in vinegars consists of bioactive compounds, such as polyphenols, Maillard reaction endproducts, etc., capable of complexing metal ions. Furthermore, transition metal ions are considered as micronutrients essential for living organisms exerting a crucial role in metabolic processes. In this study, differential pulse anodic stripping voltammetry (DPASV), a sensitive electrochemical technique considered to be a powerful tool for the study of metal speciation, was applied for the first time in vinegar samples. The concentrations of Cu complexing ligands (L_T) in 43 vinegars retailed in Greece varied between 0.05 and 52 μM, with the highest median concentration determined in balsamic vinegars (14 μM), compared to that of common vinegars (0.86 μM). In 21% of the vinegar samples examined, L_T values were exceeded by the corresponding total Cu concentrations, indicating the presence of free Cu ion and/or bound within labile inorganic/organic complexes. Red grape balsamic vinegars exhibited the highest density of Cu ligands per mass unit of organic matter compared to other foodstuffs such as herbal infusions, coffee brews, and beers. Among the 16 metals determined in vinegars, Pb is of particular importance from a toxicological point of view, whereas further investigation is required regarding potential Rb biomagnification.

Nutrient Composition and Fatty Acid and Protein Profiles of Selected Fish By-Products

Processing of fish in aquaculture generates considerable amounts of by-products that remain underused and/or unexploited. We evaluated the nutritive content of fish by-products (head, gills, intestines, trimmings, bones, and skin) from meagre and gilthead sea bream fish species reared in Greece in order to estimate their nutritional value for future development of high added-value products. The proximate composition of the fish samples (total protein, total lipid, ash, moisture, and macro-element content) was determined using the Association of Official Analytical Chemists (AOAC) and International Organization for Standardization (ISO) official methods. The content of fatty acids was determined using capillary gas chromatography, and the protein profile was estimated employing scientific orbitrap mass spectrophotometer methodology. The nutrient composition of fish by-products presented fluctuations among the different by-products. Skin was the most significant protein source, trimmings and bones were high in calcium, and the head, intestines, and bones were a good source of lipids. The most abundant lipid acids found in by-products were oleic, palmitic, linoleic, and eicosenoic acids, whereas the most abundant proteins were adenosine triphosphate (ATP) synthase subunit epsilon, mitochondrial nicotinamide adenine dinucleotide (NADH) dehydrogenase, and mitochondrial cytochrome b-c1 complex subunit 8. These data suggest that by-products constitute valuable sources of nutrients and could therefore be exploited in accordance with the principles of a circular economy.

Evaluation of Plasma Trace Elements in Different Stages of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is considered as the hepatic manifestation of metabolic syndrome. Its global prevalence is estimated between 25 and 45%, occurring mainly in overweight individuals with unhealthy dietary habits and low levels of physical activity. Many studies have investigated the association of trace elements with liver diseases, though not with NAFLD. In this work, we investigated trace element levels in plasma of patients and not-patients and their possible association with various stages of the disease. Inductively coupled plasma mass spectrometry (ICP-MS) was employed for the determination of As, Ba, Cd, Co, Cs, Cu, Fe, Rb, Sr, Tl, and Zn in the plasma of 189 free-living residents of Athens, Greece, either healthy or patients with mild, moderate, or severe NAFLD. The disease was diagnosed by abdominal ultrasound; blood samples were analyzed for total, HDL and LDL cholesterol, triglycerides, fasting glucose, fasting insulin, and liver enzymes, namely aspartate aminotransferase (AST), alanine transaminase (ALT), and γ-glutamyltransferase (Gamma-GT); insulin resistance was determined by the homeostatic model assessment (HOMA-IR). Zinc exhibited a statistically significant negative association with the severity of the disease, while cesium showed a statistically significant positive association. Moreover, thallium and iron were inversely associated with insulin levels. Trace element determination in plasma could be useful for establishing relationships with NAFLD status of patients. Further research is required for the verification and interpretation of these findings.

On the Characterization and Correlation of Compositional, Antioxidant and Colour Profile of Common and Balsamic Vinegars

Commercially available common and balsamic vinegars were examined, using a combination of spectrophotometric, chromatographic, colorimetric and spectroscopic methods. Total phenolic content, antioxidant activity, radical scavenging capacity, phenolic profile, colour parameters, Fourier Transform Infrared (FT-IR) absorbance spectra and Nuclear Magnetic Resonance (¹H NMR) spectra were comparatively studied. The main scope was the assessment of vinegar antioxidant and metabolic profiles and the identification of the most appropriate features influencing their type and subtypes. Red grape balsamic vinegars exhibited the strongest antioxidant profile. High total phenolic content and radical scavenging-antioxidant activity of vinegars was strongly correlated with high hue-angle and colour density values and low lightness and a* values. FT-IR spectra analysis confirmed the presence of organic acids and carbohydrates and, in combination with Gas Chromatography-Mass Spectrometry (GC-MS), the occurrence of phenolic compounds. NMR spectroscopy enabled the identification of 27 characteristic metabolites in each type of vinegar. The combination of all applied techniques provides critical information on compositional differences among the vinegars and could serve as an application tool for similar fermentation products.

Trace metals pollution of waters and soils in Kardjali region, Bulgaria

Trace metals pollution of surface waters and their nearby soils in the metallurgically polluted Kardjali region, Bulgaria, were studied. Thermodynamic modeling including the dissolved organic carbon (DOC) was carried out for evaluating the distribution of metal species in waters and soil solutions. Zn was found to be the most widespread pollutant in the water samples, followed by Cu, Mn, and Cd. Geoaccumulation indices of trace metals for the tested soils were calculated, indicating that regarding Al, Fe, Co, Ni, and Cu all soils are "uncontaminated". The most significant soil pollutant was found to be Cd, with all soils being either "extremely contaminated" by this metal or close to the limit, followed by Pb and Zn. The dynamics of trace metal chemical species distribution in surface waters and in the water-soluble soil fractions, as a result of possible spontaneous precipitations, was calculated by applying different thermodynamic models. Regarding Mn, Co, Ni, and Cd in waters and aqueous soil extracts and Zn in aqueous soil extracts, their free ion species prevailed, being more labile and hence toxic for the ecosystem. In the case of Al, Fe, Cu, Cd, and Pb in the waters and aqueous soil extracts and of Zn in waters, stable organic complexes with bidentate bonds, Me(OH)₄^- or Me(OH)⁰₂ prevailed.

Organic complexation of copper in throughfall and open field bulk deposition: Influence of the tree canopy of Mediterranean forest ecosystems

The complexing capacity for Cu ions (L_T) and the apparent stability constant values (logK_app) were measured in throughfall (TF) and open field bulk deposition (BD), at two Mediterranean forest ecosystems of western Greece. L_T was measured for the first time in the TF of natural forests. Concentrations of L_T were three-to-four-fold higher in TF (mean ± st.dev: 2014 ± 769 nM for Varetada and 1565 ± 595 nM for Karpenissi) compared to those in BD (531 ± 517 nM and 468 ± 321 nM, respectively). In all TF and BD samples, L_T concentrations were significantly higher than the corresponding total Cu concentrations, indicating that Cu was fully complexed. The L_T/TOC ratios in TF were found comparable between the two study sites (235 ± 149 nM mg^-1 C for Varetada and 256 ± 233 nM mg^-1 C for Karpenissi) and with those of BD (226 ± 257 and 163 ± 163 nM mg^-1 C, respectively). The determined mean logK_app values were almost identical in TF (6.8 ± 0.7 at Varetada; 6.8 ± 0.6 at Karpenissi) and BD (6.5 ± 0.6 at Varetada; 6.8 ± 0.3 at Karpenissi), pointing to the fact that regardless of the enrichment of TF in ligands (L_T(TF) > L_T(BD)) the type of binding sites remain the same. The logK_app values which were obtained herewith are similar to those obtained for humic-like substances (HULIS), indicating them as the most widespread type of ligands in BD and TF.

Predictors of cadmium and lead concentrations in the blood of residents from the metropolitan area of Athens (Greece)

The Cd and Pb blood contents of healthy adult subjects who are non-occupationally exposed and living in the metropolitan area of Athens (Greece) have not been assessed thus far. Additionally, Greeks rank first among EU27 in terms of smoking habits. To fill the existing gap, we aimed to evaluate the predictors and propose reference values (RVs) of the Cd (CdB) and Pb (PbB) blood concentrations in residents of the metropolitan area of Athens (Greece). Age, sex, smoking, alcohol drinking, educational status and nutritional habits were used as variables, with an emphasis on smoking. CdB and PbB determinations were performed directly by graphite furnace atomic absorption spectrometry (GFAAS) following the appropriate dilution of the samples with Triton-X-100. The RVs of CdB and PbB proposed for the general adult population of the Metropolitan area of Athens, Greece (upper limit of the 95% CI of the 95th percentile of the distribution of values), were 2.3 and 88μgL(-1) (P95: 1.8 and 77μgL(-1); 95% CI (P95): 1.5-2.3 and 70-88μgL(-1)), respectively. Males had a higher median CdB (0.69μgL(-1)) than females (0.55μgL(-1)). Subjects aged <40years had a lower median CdB (0.51μgL(-1)) than the elderly (≥60years; 0.60μgL(-1)). The CdB in smokers (1.2μgL(-1)) was almost threefold higher than in non-smokers (0.46μgL(-1)). The PbB levels were higher in males (31μgL(-1)) than females (20μgL(-1)). Subjects aged <40years had a lower median PbB (17μgL(-1)) than the elderly (≥60years; 32μgL(-1)). A multiple linear regression analysis demonstrated that the predictor variables for the CdB levels were the standardized beta weight, smoking, age, alcohol consumption, and intake of leafy vegetables, whereas for the PbB levels they were sex and age.

Electrochemical Evaluation of the Organic Matter Content of Edible Sea and Rock Salts Retailed in the Greek Market

The release of copper-complexing ligands in 14 sea and 10 rock edible salts retailed in the Greek market has been examined. The concentration of ligands (LT) and the copper-binding strength (logKapp) of salt solutions were determined with Differential Pulse Anodic Stripping Voltammetry (DPASV). The tested salt samples were found to have Cu complexing ligands, at concentrations ranging from <0.1 to 61.2 nmol g-1. In none of the salt samples examined (except a single one) were LTvalues exceeded by the corresponding total copper concentrations, indicating that Cu is fully complexed. Aiming to partially characterize the physico-chemical properties of the organic material contained in salts, the surface active substances (SAS) and catalytically active compounds (CAC) were measured, for the first time, in salt solutions by sensitive electrochemical techniques. Higher concentrations of organic carbon and SAS were determined in sea samples compared to rock salts.

Levels of perfluorinated compounds in raw and cooked Mediterranean finfish and shellfish

Perfluorinated compounds (PFCs) were analyzed in several species of small Mediterranean fish and shellfish, all of which are popular in Greek diet. Analysis was conducted in raw samples and in samples cooked by the two ways preferred in Greek cuisine, i.e. fried in olive oil and grilled. PFCs above the detection limit were found in all raw samples except sardine, mussel and squid. The predominant PFC was PFOS (perfluorooctane sulfonate), the highest concentration of which was measured in picarel (20.4 ng g(-1) fresh weight). The PFOS values for the rest of the samples were between <LOD and 5.66 ng g(-1) fw. The concentrations of the detected PFCs were in most cases higher after frying or grilling, this increase being statistically significant. Based on these results, the Tolerable Daily Intake for PFOS and PFOA (perfluorooctanoic acid) through consumption of fish and seafood was well below the values proposed by EFSA.

Copper complexing properties of exudates and metabolites of macroalgae from the Aegean Sea

Macroalgae are a significant source of extracellular organic material in the coastal areas of the Mediterranean, including organic ligands which serve as modulators of metal complexing capacity. This paper examines the release of copper-complexing ligands by 24 macroalgal species, including chlorophyta, rhodophyta, ochrophyta as well as Posidonia oceanica, common throughout the Mediterranean. Metabolites isolated from the algae Dictyota dichotoma and Pterocladiella capillacea were examined for the first time regarding their Cu-complexing properties. The concentration of ligands (LT) and the copper-binding strength (logKapp) of exudates and metabolites were determined by electrochemical methods. All algal species released ligands giving LT concentrations ranging from 109 to 744 nM in unfiltered samples. An increase in the concentration of ligands up to 15 times in comparison to the blank was observed after 48 h of culturing macroalgae in artificial seawater. The binding strength (log Kapp) varied among species from 7.0 to 8.6, except for the metabolites for which it was lower (log Kapp=6). Most of the ligands released were in the dissolved phase, with the contribution of particulate and/or colloidal organic matter (up to 46% of total ligands) appearing to be important only in specific macroalgal species.

Bioaccumulation of metals (Cd, Cu, Zn) by the marine bivalves M. galloprovincialis, P. radiata, V. verrucosa and C. chione in Mediterranean coastal microenvironments: association with metal bioavailability

The concentrations of Cd, Cu and Zn in both the whole soft tissue and separate organs (gills, mantle, muscle and digestive gland) of wild bivalves (Mytilus galloprovincialis, Pinctada radiata, Venus verrucosa and Callista chione) from three different coastal microenvironments of Greece were monitored from 2003 to 2004. In parallel, by employing appropriate analytical protocols for metal partitioning, the labile fraction of the metals was determined in the dissolved phase, suspended particulate matter and sediments. Differences in the metal levels were detected both among the study areas as well as among the bivalves examined. Significant bioaccumulation was demonstrated regarding Zn in M. galloprovincialis specimens from the highly industrialized Gulf of Elefsis and Cd in P. radiata and V. verrucosa from the Maliakos Gulf, which is influenced by extended agricultural activity occurring at the neighbouring area and a river outflow. Data of the metal levels in the various environmental phases were correlated with their concentrations in bivalves' tissues. The clear relationships obtained in many cases among the labile metal concentrations and the bioaccumulated concentrations in bivalves point out that the labile fraction of a metal is the most bioavailable. The lack of positive correlation for C. chione confirms the occurrence of effective mechanisms of internal regulation of metal concentrations.

Heavy metals in raw, fried and grilled Mediterranean finfish and shellfish

The effect of domestic pan-frying and grilling on Cd, Cr, Cu, Fe, Hg, Ni, Pb and Zn content of popular small Mediterranean finfish and shellfish was studied. The species selected -namely anchovy, bogue, hake, picarel, sardine, sand smelt, stripped mullet, Mediterranean mussel, shrimp and squid- are among the most commonly marketed and consumed in Greece and most of the Mediterranean countries. Both culinary practices examined resulted in increased metals concentrations compared to those of raw samples, the increment being inversely related to fish size and -in most cases- being more extended in pan-frying. The consumption of cooked seafood is expected to provide significant amounts of Fe and Zn followed, in decreasing order, by Cr, Cu and Ni. In addition, the estimation of (a) weekly intakes and (b) target hazard quotients for the toxic elements Cd, Hg and Pb revealed that the cooked fish and shellfish do not pose any health risk for the consumers.

Cadmium content in foodstuffs from the Greek market

Determinations of the cadmium content of a wide variety of foodstuffs from the Greek market were carried out. The values detected ranged from <0.1 ng x g(-1) in alcoholic beverages to 1595.8 ng x g(-1) in large snails. The highest values were observed in molluscs and crustaceans (117.4 ng x g(-1)), followed by leafy vegetables (28.3 ng x g(-1)), potatoes (22.3 ng x g(-1)) and organs and offal (20.7 ng x g(-1)), whereas the other food categories had a lower cadmium content. The results are comparable with those from the rest of Europe. Preliminary analytical data on the cadmium content of food samples of organic cultivation showed significantly lower values compared with those of samples of conventional produce.