Climate change extreme and seasonal toxic metal occurrence in Romanian freshwaters in the last two decades—case study and critical review

The relationship between metal levels in the Olt River ecosystem in southern Romania (measured during 2018‒2019, with 1064 sediment and water samples) and daily climate data were explored to assess the need for targeted source identification and mitigation strategies. In 2018, there was a strong relationship between the sediment Pb, As, Cd, and Hg contents and temperature (r > 0.8, p < 0.001). Mercury in sediments had a positive correlation with precipitation, and Hg in the water correlated with minimum temperature in May 2018 (p < 0.01). In July 2019, heavy metals were positively correlated with precipitation and negatively correlated with temperature. According to nonsymmetrical correspondence analysis, the four climate parameters analyzed were linearly correlated with the frequency of metal detection (p < 0.001) in both years. The statistical analysis showed strong relationships between heavy metal levels and climatic factors and attributed the discrepancies in elemental concentrations between 2018 and 2019 to climate warming.

The stability of major and trace element concentrations from musts to Champagne during the production process

Thirty-nine Champagnes from six different brands originating from the AOC Champagne area were analyzed for major and trace element concentrations in the context of their production processes and in relation to their geographical origins. Inorganic analyses were performed on the must (i.e., grape juice) originating from different AOC areas and the final Champagne. The observed elemental concentrations displayed a very narrow range of variability. Typical concentrations observed in Champagne are expressed in mg/L for elements such as K, Ca, Mg, Na, B, Fe, A, and Mn. They are expressed in µg/L for trace elements such as Sr, Rb, Ba, Cu, Ni, Pb Cr and Li in decreasing order of concentrations. This overall homogeneity was observed for Sr and Rb in particular, which showed a very narrow range of concentrations (150 < Rb < 300 µg/L and 150 < Sr < 350 µg/L) in Champagne. The musts contained similar levels of concentration but showed slightly higher variability since they are directly influenced by the bedrock, which is quite homogenous in the AOC area being studied. Besides the homogeneity of the bedrock, the overall stability of the concentrations recorded in the samples can also be directly linked to the successive blending steps, both at the must level and prior to the final bottling. A detailed analysis of the main additives, sugar, yeast and bentonite, during the Champagne production process, did not show a major impact on the elemental signature of Champagne.

Size-Segregated Elemental Profile and Associated Heath Risk Assessment of Road Dust along Major Traffic Corridors in Kolkata Mega City

Particle size distribution (PSD) of road dust has significant repercussions on atmospheric pollution by road dust resuspension. The PSD of road dust at a few major commercial, traffic, and residential sites in Kolkata mega city was analyzed in the size range of <28–2000 µm. Predominance of the coarse size range (212–600 µm followed by 106–212 µm) was observed. In size-segregated road dust, Fe (4.02–31.2 g kg−1) dominated other elements and was followed by Mg (2.13–10.9 g kg−1), Mn (79.2–601 mg kg−1), Li (395.8–506.8 mg kg−1), and others. Fine particles (<28 μm) had higher elemental concentrations than coarser ones. Cd and Li showed the highest degree of enrichment compared to the Earth’s crust, but only Cd posed significant ecological risk due to its high ecological toxicity. Individual elements did not post significant non-cancer health risks, except for Li in children. However, the cumulative non-cancer risk from all toxic elements for children was almost four times higher than the acceptable level. Lifetime exposure to carcinogenic elements at the current level may pose 5 to 6 times higher cancer risk in the adult population than the acceptable risk of one in a million.

The use of different concentrations of Nickel and Lead for the inhibition growth of some types of soil microorganisms

Three types of Mycorrhiza has been chosen R. rosulus, S. varigatus and P. involutus in removing and lowering the ascending concentration of nickel and lead elements during three incubation and contact periods (5,7 and 10 days), and comparing the isolated growth with control sample. Type of P. involutus is the most efficient in the removal by observing the growth of isolates by increasing it's diameter compared to the control samples and the concentration of nickel and lead, and for all the days of incubation, while the type S. varigatus was the highest growth at low concentration of nickel and lead only for all periods of incubation, for type R. rosulus, the diameter was smaller as compared to control samples and for all elements concentration of nickel and lead, except at concentration (2.5ppm), which showed increase in diameter for nickel, and is generally observed increase diameters of the isolates of the three types by increasing periods of incubation and all elemental concentrations of nickel and lead, and this increase is less than at high concentrations of these elements and of all species studied.

Hydroclimate change in the Garhwal Himalaya, India at 4200 yr BP coincident with the contraction of the Indus civilization

High-resolution analysis of a 3.80 m sediment core recovered from Deoria Tal, a mid-elevation lake located at 2393 m a.s.l. in the Garhwal Himalaya, documents long-term and abrupt hydroclimate fluctuations in northern India during the mid- to late Holocene. The sediment chronology, based on ten 14C dates, indicates the core spans 5200 years. Non-destructive, radiological imaging approaches (X-ray fluorescence (XRF), X-ray imaging, and CT scans) were used to assess the response of the lake system to changing hydroclimatic conditions. Variations in elemental concentrations and sediment density evidenced notable hydroclimate change episodes centered at 4850, 4200, and 3100 cal yr BP. Elevated detrital input, greater sediment density, decreased lake ventilation, and lower autochthonous productivity reflects lake deepening between 4350 and 4200 cal yr BP. An abrupt shift in elemental concentrations and sediment density indicated the onset of lake drawdown at 4200 cal yr BP and a negative hydroclimate anomaly between 4200 and 4050 cal yr BP. Lower detrital flux, decreased sediment density, increased oxygenation, and higher autochthonous productivity, reflects a reduction in lake volume between 3200 and 3100 cal yr BP. The potential link between abrupt climate change at 4200 cal yr BP and the contraction of the Indus civilization is explored.

Strain-hardening properties of the high-entropy alloy MoNbTaTiVZr processed by high-pressure torsion

An equiatomic MoNbTaTiVZr refractory high-entropy alloy (HEA) produced by arc melting was processed by high-pressure torsion (HPT) at room temperature. Thermodynamic calculations and experimental results indicated a dual-phase microstructure composed of about 85% BCC Zr-depleted and 15% BCC Zr-rich phase in the as-cast condition. HPT causes grain refinement and an increase in dislocation density without the formation of new phases. After four revolutions, the Zr-depleted phase was hardened to $$\sim $$ ∼ 540 HV, while the Zr-rich phase exhibited softening with a decrease in hardness to $$\sim $$ ∼ 480 HV. The occurrence of a vortex-like microstructure and the analysis of elemental concentrations indicated a shear-induced mechanical homogenization, which was supposed to be the cause of the observed softening.

Stable Isotope, Major and Trace Element Chemistry of Modern Snow from Evans Piedmont Glacier, Antarctica: Insights into Potential Source Regions and Relationship of Glaciochemistry to Atmospheric Circulation and Vigour

<p>This thesis presents a sub-seasonally resolved, decade long record of snow pack chemistry from Evans Piedmont Glacier (EPG), southern Victoria Land coast, Antarctica. Snow chemistry measurements were made at ca. 20 analyses per year for stable isotope ratios [delta to the power of 18]O and [delta]D, major ions Ca+, Cl-, K+, Mg+, MS-, Na+, NO3-, SO42- by ion chromatography (IC), and major and trace element chemistry by inductively coupled plasma mass spectrometry (ICP-MS). Na, Mg, Al, Fe, Mn and Ba were measured by ICP-MS using a hydrogen flushed collision cell to reduce the formation of polyatomic ion interferences, whereas Ti, V, Cr, Ni, Cu, Zn, As, Rb, Sr, Y, Zr, Sb, Cs, Ba, La, Ce, Pb, Bi, Th and U were measured in non-collision cell mode to increase count sensitivity. ICP-MS analytical precision is typically 5 to 10 % (2 rsd) that is two orders of magnitude at minimum below natural variability (e.g. samples range between Na = 10 to 18031 ppb and Al = 5 to 3856 ppb). The presence of undigested mineral dusts in weakly acidified samples, however, complicates the measurement of elemental concentrations in snow samples by randomly entering the ICP-MS. Despite this, the range of sample concentrations (Zr = 3.0 to 5630 ppb) is still orders of magnitude higher than sample reproducibility. The dominant source regions of element chemistry transported to EPG snow are identified as marine (Na, Mg, SO4, Cl, K, As and Sr) and terrestrial derived aerosol (Al, Mn, Fe, Ba, Ti, V, Ni, Cr, Zn, Rb, Y, Zr, Cd, Sb, Cs, Ba, La, Ce, Pb, Th and U), with minor contributions from anthropogenic (V, Cr, Ni, Cu, Zn, As, Sb and Pb) and volcanic emissions (Bi, SO4 and K). This is based on both elemental ratio modelling and ICP-MS time resolved analysis that identifies elements present in particulate form (mineral dusts). EPG snow chemistry is related to measured meteorological conditions at nearby Cape Ross. Winter maxima of elemental concentrations is consistent with maximum winter wind speed and low precipitation rates. Furthermore, winter snow samples that are depleted in SO42- relative to other marine derived elements (e.g. Na), indicate the sea ice surface is an important source of marine aerosol transported to EPG in addition to an open ocean source. Annual maximum chemistry concentrations of terrestrial derived elements (e.g. Zr) are significantly correlated to maximum annual wind speed measured at Cape Ross (r2 = 0.68, p< 0.01). Lower correlation of marine derived chemistry (e.g. Na) and maximum wind strength reflects additional controls of source region and other meteorological parameters such as storm duration on marine derived chemistry. In contrast to elemental concentrations, elemental ratios are less sensitive to extreme wind conditions. Rather elemental ratios provide a more robust signature of changes in mean atmospheric circulation related to delivery of aerosol from different source regions and via different transport fractionation processes. Al/Na is controlled by variable delivery of terrestrial (Al) and marine (Na) aerosol to EPG, although the longer term trend is driven primarily by changes in Na. Al/Na is significantly higher between winter 2000 and summer 2006/07 with a mean value of Al/Na = 0.15 compared to Al/Na = 0.02 prior to 2000. Although sea ice extent was highly variable over this time period, there is no clear relationship between Al/Na and sea ice. Rather, Al/Na is significantly correlated to mean summer wind speed measured at Cape Ross (r2 = -0.51, p<0.01). This demonstrates the sensitivity of Al/Na to changes in the average transport of marine aerosol to EPG during summer, when an open ocean source is most proximal. The shift in Al/Na is also concurrent with a shift in the relationship between [delta]18O and d excess, indicative of a changing precipitation source region to EPG. The observed changes in EPG chemistry are concurrent with shifts in mean Southern Oscillation Index (SOI), a measure of the El Nino Southern Oscillation (ENSO) strength and polarity. Al/Na is low when SOI is predominantly negative (El Nino), associated with increased summer wind strength. This is in accordance with a strong Amundsen Sea Low, positioned directly north of the Ross Sea as previously reported during El Nino years. Although the establishment of a statistically significant relationship between SOI and EPG Al/Na ratios is inhibited by the brevity of this record, this study highlights the potential for the 180 m firn core also extracted from EPG to track long-term changes in SOI. Elemental chemistry of EPG provides a high resolution tool to reconstruct atmospheric circulation changes within the southern Ross Sea region.</p>

Stable Isotope, Major and Trace Element Chemistry of Modern Snow from Evans Piedmont Glacier, Antarctica: Insights into Potential Source Regions and Relationship of Glaciochemistry to Atmospheric Circulation and Vigour

<p>This thesis presents a sub-seasonally resolved, decade long record of snow pack chemistry from Evans Piedmont Glacier (EPG), southern Victoria Land coast, Antarctica. Snow chemistry measurements were made at ca. 20 analyses per year for stable isotope ratios [delta to the power of 18]O and [delta]D, major ions Ca+, Cl-, K+, Mg+, MS-, Na+, NO3-, SO42- by ion chromatography (IC), and major and trace element chemistry by inductively coupled plasma mass spectrometry (ICP-MS). Na, Mg, Al, Fe, Mn and Ba were measured by ICP-MS using a hydrogen flushed collision cell to reduce the formation of polyatomic ion interferences, whereas Ti, V, Cr, Ni, Cu, Zn, As, Rb, Sr, Y, Zr, Sb, Cs, Ba, La, Ce, Pb, Bi, Th and U were measured in non-collision cell mode to increase count sensitivity. ICP-MS analytical precision is typically 5 to 10 % (2 rsd) that is two orders of magnitude at minimum below natural variability (e.g. samples range between Na = 10 to 18031 ppb and Al = 5 to 3856 ppb). The presence of undigested mineral dusts in weakly acidified samples, however, complicates the measurement of elemental concentrations in snow samples by randomly entering the ICP-MS. Despite this, the range of sample concentrations (Zr = 3.0 to 5630 ppb) is still orders of magnitude higher than sample reproducibility. The dominant source regions of element chemistry transported to EPG snow are identified as marine (Na, Mg, SO4, Cl, K, As and Sr) and terrestrial derived aerosol (Al, Mn, Fe, Ba, Ti, V, Ni, Cr, Zn, Rb, Y, Zr, Cd, Sb, Cs, Ba, La, Ce, Pb, Th and U), with minor contributions from anthropogenic (V, Cr, Ni, Cu, Zn, As, Sb and Pb) and volcanic emissions (Bi, SO4 and K). This is based on both elemental ratio modelling and ICP-MS time resolved analysis that identifies elements present in particulate form (mineral dusts). EPG snow chemistry is related to measured meteorological conditions at nearby Cape Ross. Winter maxima of elemental concentrations is consistent with maximum winter wind speed and low precipitation rates. Furthermore, winter snow samples that are depleted in SO42- relative to other marine derived elements (e.g. Na), indicate the sea ice surface is an important source of marine aerosol transported to EPG in addition to an open ocean source. Annual maximum chemistry concentrations of terrestrial derived elements (e.g. Zr) are significantly correlated to maximum annual wind speed measured at Cape Ross (r2 = 0.68, p< 0.01). Lower correlation of marine derived chemistry (e.g. Na) and maximum wind strength reflects additional controls of source region and other meteorological parameters such as storm duration on marine derived chemistry. In contrast to elemental concentrations, elemental ratios are less sensitive to extreme wind conditions. Rather elemental ratios provide a more robust signature of changes in mean atmospheric circulation related to delivery of aerosol from different source regions and via different transport fractionation processes. Al/Na is controlled by variable delivery of terrestrial (Al) and marine (Na) aerosol to EPG, although the longer term trend is driven primarily by changes in Na. Al/Na is significantly higher between winter 2000 and summer 2006/07 with a mean value of Al/Na = 0.15 compared to Al/Na = 0.02 prior to 2000. Although sea ice extent was highly variable over this time period, there is no clear relationship between Al/Na and sea ice. Rather, Al/Na is significantly correlated to mean summer wind speed measured at Cape Ross (r2 = -0.51, p<0.01). This demonstrates the sensitivity of Al/Na to changes in the average transport of marine aerosol to EPG during summer, when an open ocean source is most proximal. The shift in Al/Na is also concurrent with a shift in the relationship between [delta]18O and d excess, indicative of a changing precipitation source region to EPG. The observed changes in EPG chemistry are concurrent with shifts in mean Southern Oscillation Index (SOI), a measure of the El Nino Southern Oscillation (ENSO) strength and polarity. Al/Na is low when SOI is predominantly negative (El Nino), associated with increased summer wind strength. This is in accordance with a strong Amundsen Sea Low, positioned directly north of the Ross Sea as previously reported during El Nino years. Although the establishment of a statistically significant relationship between SOI and EPG Al/Na ratios is inhibited by the brevity of this record, this study highlights the potential for the 180 m firn core also extracted from EPG to track long-term changes in SOI. Elemental chemistry of EPG provides a high resolution tool to reconstruct atmospheric circulation changes within the southern Ross Sea region.</p>