The Remediation of Dysprosium-Containing Effluents Using Cyanobacteria Spirulina platensis and Yeast Saccharomyces cerevisiae

Dysprosium is one of the most critical rare earth elements for industry and technology. A comparative study was carried out to assess the biosorption capacity of cyanobacteria Spirulina platensis and yeast Saccharomyces cerevisiae toward dysprosium ions. The effect of experimental parameters such as pH, dysprosium concentration, time of contact, and temperature on the biosorption capacity was evaluated. Biomass before and after dysprosium biosorption was analyzed using neutron activation analysis and Fourier-transform infrared spectroscopy. For both biosorbents, the process was quick and pH-dependent. The maximum removal of dysprosium using Spirulina platensis (50%) and Saccharomyces cerevisiae (68%) was attained at pH 3.0 during a one-hour experiment. The adsorption data for both biosorbents fitted well with the Langmuir isotherm model, whereas the kinetics of the process followed the pseudo-second-order and Elovich models. The maximum biosorption capacity of Spirulina platensis was 3.24 mg/g, and that of Saccharomyces cerevisiae was 5.84 mg/g. The thermodynamic parameters showed that dysprosium biosorption was a spontaneous process, exothermic for Saccharomyces cerevisiae and endothermic for Spirulina platensis. Biological sorbents can be considered an eco-friendly alternative to traditional technologies applied for dysprosium ion recovery from wastewater.

Geochemical Responses to Natural and Anthropogenic Settings in Salt Lakes Sediments from North-Eastern Romanian Plain

Chemical analysis was performed on sediment core samples collected from three salt lakes, Amara Lake, Caineni Lake, and Movila Miresii Lake, located in the northeast of the Romanian Plain. The concentration of 10 main elements, 6 heavy metals (HMs), 8 rare earth elements (REEs), and 10 trace elements (TEs)-determined using neutron activation analysis (NAA)-showed variability dependent on the depth sections, lake genesis and geochemical characteristics (oxbow, fluvial harbor/liman and loess saucer type). The assessment of pollution indices (contamination factor, pollution load index, geoaccumulation index, and enrichment factor) highlighted low and moderate degrees of contamination for most of the investigated elements. Principal component analysis (PCA) extracted three principal components, explaining 70.33% (Amara Lake), 79.92% (Caineni Lake), and 71.42% (Movila Miresii Lake) of the observed variability. The principal components extracted were assigned to pedological contribution (37.42%-Amara Lake, 55.88%-Caineni Lake, and 15.31%-Movila Miresii Lake), salts depositions (due to the lack of a constant supply of freshwater and through evaporation during dry periods), atmospheric deposition (19.19%-Amara Lake, 13.80%-Caineni Lake, and 10.80%-Movila Miresii Lake), leaching from soil surface/denudation, rock weathering, and mixed anthropogenic input (e.g., agricultural runoff, wastewater discharges) (13.72%-Amara Lake, 10.24%-Caineni Lake, and 45.31%-Movila Miresii Lake).

Determination of Multi Elements in Tobacco Plant of Northeast India by Neutron Activation Analysis and Atomic Absorption Spectrometry

Even when cultivated in uncontaminated soils, tobacco plant has higher propensity to extract and accumulate trace elements. The concentrations (mass fractions) of essential elements (K, Ca, Mg, Na, Cl, Mn, Fe, Cu, and Zn) and 28 non-essential elements in tobacco plant (leaves, stem, and root) of Northeast India and their respective soils were quantitatively measured. Hg mass fraction in all samples analyzed were found to be < 10 mg/kg. The heavy element mass fractions of tobacco are weakly correlated to different soil parameters. The bioconcentration factor values indicated that Cd (7) is selectively absorbed and translocated in the tobacco leaves compared to Zn (1.7), Cu (1.5), Ni (0.12), and Pb (0.1). Under acidic soil conditions, tobacco plant efficiently absorbed and translocated Cl- ion with great ease, whereas it may be a very low accumulator of rare-earth elements. The mass fractions of Mn, Cu, Sb, Cs, Rb, and Pb are very similar to the "reference plant," whereas significantly higher mass fractions of Al, Sc, Ti, Zr, Hf, Ta, Th, and U are present in the roots of tobacco plant relative to the "reference plant." Principal component analysis has revealed that Northeast Indian tobacco can be clearly differentiated from other varieties of tobaccos used in different countries because of their element profiles.

Moss Biomonitoring of Atmospheric Trace Element Pollution in the Republic of Moldova

The moss biomonitoring technique was used for the assessment of air pollution in the Republic of Moldova, in the framework of the UNECE ICP Vegetation Programme. The content of 11 chemical elements (Al, V, Cr, Fe, Ni, Zn, As, Sb, Cd, Cu, and Pb) was determined by neutron activation analysis and atomic absorption spectrometry in samples collected in spring 2020. Distribution maps were built to identify the most polluted sites. The highest concentrations of elements in mosses were determined in the north-eastern, central, and western parts of the country. The main element associations were identified using factor analysis. Three factors were determined, of which one of mixed geogenic-anthropogenic origin and two of anthropogenic origin. A comparison of the data obtained in 2020 and 2015 showed a significant decrease in the concentrations of Cr, As, Sb, Cd, Pb, and Cu in 2020. The state of the environment was assessed using Contamination Factor and Pollution Load Index values, which characterized it as unpolluted to moderately polluted. Possible air pollution sources in the Republic of Moldova are resuspension of soil particles, agricultural practices, vehicles, industry, and thermal power plants.

Moss Biomonitoring of Atmospheric Pollution with Trace Elements in the Moscow Region, Russia

For the first time, moss biomonitoring covering the territory of the entire Moscow region, without including Moscow, was performed in 2020. Moss Pleurozium schreberi collected at 156 sampling sites were analyzed using neutron activation analysis and atomic absorption spectrometry. A total of 34 elements were determined in moss samples. Obtained data were compared with the results of the moss surveys performed in the Vladimir and Yaroslavl regions in 2018 and with the data of moss surveys conducted in the Moscow region on a limited number of sampling sites in 2004 and 2014. The Moscow region showed to be more polluted than the Vladimir and Yaroslavl regions. In the the Moscow region, the decrease of the content of the main part of the elements over time was noted. Trace elements emission sources were identified and characterized using factor analysis. Contamination Factor, Pollution Load Index, and Ecological Risk were calculated to assess the level of the region contamination and elements effect on human health. In general, the Moscow region can be characterized as unpolluted to moderately polluted with a low ecological risk of human exposure. The cities satellites around Moscow were determined to experience particular environmental stress, even in the period of the COVID-19 restrictions.

Comparison of non-destructive techniques and conventionally used spectrometric techniques for determination of elements in plant samples (coniferous leaves)

Conventionally used spectrometric techniques of inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma optical emission spectrometry (ICP-MS) usually involve time-consuming sample preparation procedure of a sample dissolution which requires the usage of aggressive and toxic chemicals. The need for suitable and sustainable analytical methods for direct multi-elemental analysis of plant samples has been increased in recent years. Spectrometric techniques for direct sample analysis, instrumental neutron activation analysis (INAA) and X-ray fluorescence (XRF) have been applied in environmental studies and various fields of screening tests. Nevertheless, these techniques are not commonly used for plant sample analysis and their performances need to be evaluated. This research aimed to assess how reliable non-destructive techniques are in the determination of elements in plants compared to conventionally used spectrometric techniques. A total of 49 plant samples of four conifer species (Pinus nigra, Abies alba, Taxus baccata and Larix decidua) were measured using two conventionally applied (ICP-MS, ICP-OES) and two non-destructive techniques (wavelength dispersive XRF (WD-XRF), INAA). The comparison was performed by investigation of relative ratios of concentrations and by correlation analysis. Moreover, precision of the techniques was examined and compared. The quality control included analysis of NIST pine needles certified reference material (1575a) using all examined techniques. Our results suggest that additional analytical and quality control steps are necessary for reaching the highest accuracy of multi-elemental analysis.

The Effect of TiO2 Nanoparticles on the Composition and Ultrastructure of Wheat

The present work aims to follow the influence of TiO2 nanoparticles (TiO2 NPs) on bioactive compounds, the elemental content of wheat, and on wheat leaves' ultrastructure. Synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and transmission electron microscopy (TEM). The concentration of phenolic compounds, assimilation pigments, antioxidant capacity, elemental content, as well as the ultrastructural changes that may occur in the wheat plants grown in the presence or absence of TiO2 NPs were evaluated. In plants grown in the presence of TiO2 NPs, the amount of assimilating pigments and total polyphenols decreased compared to the control sample, while the antioxidant activity of plants grown in amended soil was higher than those grown in control soil. Following ultrastructural analysis, no significant changes were observed in the leaves of TiO2-treated plants. Application of TiO2 NPs to soil caused a significant reaction of the plant to stress conditions. This was revealed by the increase of antioxidant capacity and the decrease of chlorophyll, total polyphenols, and carotenoids. Besides, the application of TiO2 NPs led to significant positive (K, Zn, Br, and Mo) and negative (Na, Mn, Fe, As, Sr, Sb, and Ba) variation of content.

Effect of zinc-containing systems on Spirulina platensis bioaccumulation capacity and biochemical composition

Cyanobacteria Spirulina platensis due to its high biosorption and bioaccumulation capacity toward metal ions can be considered as an excellent candidate for environmental bioremediation. The effect of Zn and in different combinations on the accumulation capacity of Spirulina platensis biomass and its biochemical composition was investigated. Four Zn-containing systems with a different combination of metal ions (Zn; Zn/Cu/Sr; Zn/Cu/Ni; Zn/Cu/Sr/Ba) and different metal concentrations were modeled. Studied systems were introduced in the cultivation medium on the fifth day of biomass grow and experiments were performed in three variants, which differed by metal ions concentrations. Metal uptake by biomass was traced using neutron activation analysis. Spirulina platensis showed a high accumulation capacity for all metal ions present in the analyzed system. Because the metals were added at the beginning of the stationary growth phase, the contact with the biomass was only 24 h, even at the highest metal concentration in the systems, the accumulation of Spirulina platensis biomass was reduced by no more than 11.2%. Spirulina platensis biomass grown in a mono-metallic system expressed two biochemical indicators of stress: decrease of phycobiliprotein content and increase of malondialdehyde content. In biomass grown in the presence of Zn-containing multi-metallic systems, three indicators of stress were expressed: decrease of protein content, reduction of phycobiliprotein content, and increase of malondialdehyde content. Spirulina platensis biomass can be considered as an effective accumulator for the treatment of zinc-containing industrial effluents.

The Effect of Heavy Industry on Air Pollution Studied by Active Moss Biomonitoring in Donetsk Region (Ukraine)

The active moss biomonitoring technique was applied to assess the environmental pollution in the Donetsk region and to compare the biomonitoring capacity of acrocarpous (Ceratodon purpureus) and pleurocarpous (Brachythecium campestre) moss transplants. Moss bags were exposed for 6 months in the surroundings of two steelworks, a power station, and two parks. The concentrations of 19 elements were determined in the moss transplants by neutron activation analysis and atomic absorption spectrometry. Various environmental indices-relative accumulation factor, contamination factor, pollution load index, enrichment factor, and ecological risk index-were used to quantitatively assess the degree of ambient contamination. The RAF values indicate that the most prevalent elements in Brachythecium campestre and Ceratodon purpureus were Na, Al, Ca, Fe, Ti, V, Cr, Mn, Co, Ni, Zn, Ba, Sr, Pd, and Cd. The results showed a significant difference between metal accumulation by Ceratodon purpureus and Brachythecium campestre indicating various mechanisms of uptake. All elements were highly correlated in Ceratodon purpureus. The main air pollution sources in the region are the Zuivska power station (Zuivska TES), Donetsk Metallurgical Plant, and Yenakiieve Iron and Steel Works.

Characterization of Trace Elements in Atmospheric Deposition Studied by Moss Biomonitoring in Georgia

The present work was conducted to obtain and highlight the first comprehensive baseline data on atmospheric deposition of trace elements and to evaluate the air quality in Georgia. A total of 120 moss samples were collected over accessible territories in Georgia in the period from 2014 to 2017. Hylocomium splendens (Hedw.) Schimp., Hypnum cupressiforme (Hedw.), and Pleurozium schreberi (Brid.) Mitt. moss species were analyzed by two complementary analytical techniques: instrumental neutron activation analysis and atomic absorption spectrometry. Concentrations of 41 elements in mg/kg were determined. The concentrations were compared with the corresponding values in the literature and are in a good agreement, except for the concentration of Mg, Al, K, Ca, Ti, and Fe, which were higher than those reported for other countries. The principal component and discriminant analyses were implemented to extract information about the similar geochemical features and to decipher the provenance of the studied elements. The analysis showed that a considerable association of crustal elements and the provenance of elements can be considered as a mixture of geogenic and anthropogenic sources. In addition, the influence of different latitudinal climate zones on the distribution of elements in the atmospheric deposition was observed. The enrichment factor shows considerable values for Th and Zr. The spatial distribution of the pollution load index identifies four zones (#12, 38, 53, and 64). The potential ecological risk index and the risk index were calculated and it does not pose significant risk except As and Cd. The data obtained can be used as the first dataset of metal characterization of air pollution in Georgia.

Environmental pollution influence to soil-plant-air system in organic vineyard: bioavailability, environmental, and health risk assessment

This study was performed in organic vineyard to assess integrated pollution in soil-plant-air system by potentially toxic elements (PTE). Concentrations of 26 PTE were determined in soil, grapevine, and air biomonitors (moss bags) using ICP-OES and ICP-MS. Environmental implication assessment of soil did not show pollution by PTE, except for B in samples collected in the middle of grapevine season (July). Despite low total Cd concentrations in soil, it has the highest influence on increase of environmental risk. Based on biological accumulation concentration (BAC), grapevine is not hyperaccumulator of PTE from soil. Advanced classification algorithm, Kohonen self-organizing map (SOM), was applied to compare environmental implications in organic with conventional vineyards. PTE concentrations were significantly lower in organic than conventional grapevine. PTE concentrations were higher in the outer (leaf and petiole) than in the inner grapevine parts (skin, pulp, and seed). Some airborne elements have an influence on outer grapevine parts, especially on leaves (ratio factor-RF > 1). Moss bag technique testified about lower enrichment of airborne elements compared with the conventional vineyard and urban microenvironments. Environmental and health risk assessments confirmed that organic production is harmless for field workers and grape consumers.

Metal Removal from Nickel-Containing Effluents Using Mineral-Organic Hybrid Adsorbent

Nickel is one of the most dangerous environmental pollutants and its removal from wastewater is an important task. The capacity of a mineral–organic hybrid adsorbent, consisting of Shewanella xiamenensis biofilm and zeolite (clinoptilolite of the Chola deposit), to remove metal ions from nickel-containing batch systems under different experimental conditions was tested. The obtained biosorbent was characterized using neutron activation, SEM, and FTIR techniques. It was established that maximum removal of cations, up to 100%, was achieved at pH 6.0. Several mathematical models were applied to describe the equilibrium and kinetics data. The maximum adsorption capacity of the hybrid biosorbent, calculated using the Langmuir model, varied from 3.6 to 3.9 mg/g. Negative Gibbs energy values and positive ∆H° values indicate the spontaneous and endothermic character of the biosorption process. The effects of several parameters (pH and biosorbent dosage) on Ni(II) removal from real effluent, containing nickel with a concentration of 125 mg/L, were investigated. The optimal pH for Ni(II) removal was 5.0–6.0 and an increase of sorbent dosage from 0.5 to 2.0 led to an increase in Ni(II) removal from 17% to 27%. At two times effluent dilution, maximum Ni(II) removal of 26% was attained at pH 6.0 and sorbent dosage of 1.0 g. A 12-fold effluent dilution resulted in the removal of 72% of Ni(II) at the same pH and sorbent dosage values. The obtained hybrid biosorbent can be used for Ni(II) removal from industrial effluents with low Ni(II) concentrations.

The Recovery of Soybean Plants after Short-Term Cadmium Stress

Background: Cadmium is a non-essential heavy metal, which is toxic even in relatively low concentrations. Although the mechanisms of Cd toxicity are well documented, there is limited information concerning the recovery of plants after exposure to this metal. Methods: The present study describes the recovery of soybean plants treated for 48 h with Cd at two concentrations: 10 and 25 mg/L. In the frame of the study the growth, cell viability, level of membrane damage makers, mineral content, photosynthesis parameters, and global methylation level have been assessed directly after Cd treatment and/or after 7 days of growth in optimal conditions. Results: The results show that exposure to Cd leads to the development of toxicity symptoms such as growth inhibition, increased cell mortality, and membrane damage. After a recovery period of 7 days, the exposed plants showed no differences in relation to the control in all analyzed parameters, with an exception of a slight reduction in root length and changed content of potassium, magnesium, and manganese. Conclusions: The results indicate that soybean plants are able to efficiently recover even after relatively severe Cd stress. On the other hand, previous exposure to Cd stress modulated their mineral uptake.

Heavy Metal Atmospheric Deposition Study in Moscow Region, Russia

The air quality in north-eastern part of Moscow region was evaluated by trace metals atmospheric deposition using moss Pleurozium schreberi as bioindicator. Thirty six elements were determined in analyzed samples by Neutron activation analysis and Atomic absorption spectrometry. Principal component analysis was used to identify and characterize different pollution sources. Maps showing the geographical distribution of the factor scores were built using ArcGis software. Median values of the elements studied were compared with data obtained for other regions in Russia. The present survey showed that industrial activity, thermal power plants and transport still have the largest anthropogenic impact on air pollution in studied region.

The first survey of airborne trace elements at airport using moss bag technique

Air traffic represents an important way of social mobility in the world, and many ongoing discussions are related to the impacts that air transportation has on local air quality. In this study, moss Sphagnum girgensohnii was used for the first time in the assessment of trace element content at the international airport. The moss bags were exposed during the summer of 2013 at four sampling sites at the airport 'Nikola Tesla' (Belgrade, Serbia): runway (two), auxiliary runway and parking lot. According to the relative accumulation factor (RAF) and the limit of quantification of the moss bag technique (LOQ_T), the most abundant elements in the samples were Zn, Na, Cr, V, Cu and Fe. A comparison between the element concentrations at the airport and the corresponding values in different land use classes (urban central, suburban, industrial and green zones) across the city of Belgrade did not point out that the air traffic and associated activities significantly contribute to the trace element air pollution. This study emphasised an easy operational and robust (bio)monitoring, using moss bags as a suitable method for assessment of air quality within various microenvironments with restriction in positioning referent instrumental devices.

Air Pollution Study in the Republic of Moldova Using Moss Biomonitoring Technique

Moss biomonitoring using the species Hypnum cupressiforme (Hedw.) and Pleurocarpous sp was applied to study air pollution in the Republic of Moldova. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Cd, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Hf, Ta, W, Pb, Th, and U) were determined by instrumental epithermal neutron activation analysis and atomic absorption spectrometry. Principal component analysis was used to identify and characterize different pollution sources. Geographical distribution maps were prepared to point out the regions most affected by air pollution and relate this to potential sources of contamination. Median values of the elements studied were compared with data from the European moss biomonitoring program. The cities of Chisinau and Balti were determined to experience particular environmental stress.