Concentrations Of Mobile Elements Research Articles

Effects of pruning on mineral nutrients and untargeted metabolites in fresh leaves of Camellia sinensis cv. Shuixian.

Pruning is an important strategy for increasing tea production. However, the effects of pruning on tea quality are not well understood. In this study, tea leaves were collected from Wuyi Mountain for both ionomic and metabolomic analyses. A total of 1962 and 1188 fresh tea leaves were respectively collected from pruned and unpruned tea plants sampled across 350 tea plantations. Ionomic profiles of fresh tea leaves varied significantly between pruned and unpruned sources. For tea plants, pruning was tied to decreases in the concentrations of mobile elements, such as nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg), and dramatic increases in the concentrations of the immobile ions calcium (Ca), aluminum (Al), manganese (Mn), boron (B) and cobalt (Co). Clustering and heatmap analysis showed that pruning also affected tea leaf metabolism. Among 85 metabolites that were significantly impacted by pruning, 30 were identified through random forest analysis as characteristic differential metabolites with a prediction rate of 86.21%. Redundancy analysis showed that pruning effects on mineral nutrient concentrations accounted for 25.54% of the variation in characteristic metabolites between treatments, with the highest contributions of 6.64% and 3.69% coming from Ca and Mg, respectively. In correlation network analysis, Ca and Mg both exhibited close, though opposing correlations with six key metabolites, including key quality indicators 1,3-dicaffeoylquinic acid and 2-O-caffeoyl arbutin. In summary, large scale sampling over hundreds of tea plantations demonstrated that pruning affects tea quality, mainly through influences on leaf mineral composition, with Ca and Mg playing large roles. These results may provide a solid scientific basis for improved management of high-quality tea plantations.

Relationship of groundwater geochemistry and flow to volcanic stratigraphy in basaltic aquifers affected by magmatic CO2, Jeju Island, Korea

Groundwater from pristine volcanic rock aquifers on dormant Jeju Island, Korea, was investigated to identify sources and geochemical processes of dissolved inorganic carbon (DIC) and related solutes along with characteristics of groundwater flow using a multi-isotope approach. δ18O, δ2H, and 3H of groundwater indicated the water is of meteoric origin, and is mainly derived from recent recharge, except Na-rich mineral water which has a significant contribution of 3H-free old water. 87Sr/86Sr of dissolved Sr suggests that solutes in groundwater were mainly derived from old alkali basalt in the lower part of lava flows. δ13CCO2(g) calculated using δ13CDIC and measured hydrogeochemical parameters indicated that (1) biogenic soil CO2 is a dominant source of DIC in low mineralized water, (2) CO2-rich water had mostly mantle-derived magmatic CO2, and (3) mineral water contained both biogenic and magmatic CO2. δ13CCO2(g) in mineral water was affected by precipitation of calcite, which complicated the estimation of the contribution of CO2 sources to DIC. Concentrations of mobile elements were mainly controlled by the amount of magmatic CO2 and groundwater residence time. δ13CCO2(g) and 3H content were used to distinguish four types of groundwater with different spatial patterns of occurrence in relation to the volcanic stratigraphy of Jeju Island. Groundwater types I and II are low mineralized water with lower levels of DIC from biogenic CO2, composed of either recent recharge (<40years, type I) or older water with negligible 3H (>60years, type II). Type III is Mg-rich mineral water with significant recent recharge while type IV is Na-rich mineral water with older residence time. Types III and IV had somewhat elevated levels of DIC (up to 7.6mM) with mixed signatures of magmatic and biogenic CO2, while CO2-rich water (a subset of type III) had DIC up to 100mM with signatures of mantle-derived magmatic CO2. Groundwater in the eastern area of Jeju Island is mostly type I, which can be attributed to a lack of both low-permeability rocks and recent volcanic rocks in that area. Types III and IV were found in the western area where the latest volcanic rocks are distributed. In the southwestern area, type III is associated with permeable basaltic aquifers with a contribution of magmatic CO2 and type IV is from the younger lava flows dissected by older massive trachytic rocks and shallower hydrovolcanic tuffs, which led to the higher degree of mineralization. A conceptual model is proposed to integrate the chemical and isotopic constraints of groundwater with volcanic stratigraphy and suggest the processes that generated groundwater types with different residence times and chemical compositions. This study may contribute to understanding the processes of groundwater flow and mineralization in volcanic aquifers affected by deep-source CO2 and variable residence time of groundwater in both dormant and active volcanic areas.

Geochemical records in Holocene lake sediments of northern China: Implication for natural and anthropogenic inputs

Daihai Lake is located in a hydrologically closed basin within the transitional zone of the East Asian monsoon, which has experienced significant lake-level fluctuations. The sedimentary sequence of a 12.08 m core was analyzed for mobile (Ca, Mg, and Sr) and immobile elements (Al and Fe) and trace metals (e.g., Co, Ni, Cu, Zn, and Pb) in order to study the changes of natural chemical compositions and the potential influences of the historical mining and use of metals during the Holocene period. Climate changes have a significant influence on the concentrations of mobile elements in the Holocene lake sediment; high concentrations occurred during the times with high lake level, resulting from enhanced catchment weathering due to strong monsoon effects. Different from these mobile elements, the variation of immobile elements and trace metals in Daihai Lake sediment shows clear anthropogenic impact of the mining and use of metals in the last several millenniums. A gradual increase in the concentrations and fluxes of metals from ∼5000 cal. a B.P. is correlated well with the emergence of Chinese civilization. The concentrations and fluxes of these metals and immobile elements in the sediments increased rapidly between 2100 and 1250 cal. a B.P., indicating the extensive use of metals during the Warring States Period (475–221 B.C.), and the early Han Dynasty (206 B.C.–220 A.D.). Further increase of trace metals, such as Cu, Ni, Co, and Pb, after the Medieval Warm Period (1200–800 a B.P.) likely reflects the increased metal emissions associated with extensive mining and utilization activities. Similar patterns of sedimentary metals between Daihai Lake in northern China and Liangzhi Lake in central China further indicate significant environmental impacts of the mining and utilization of metals in the progress of Chinese civilization in the past several thousand years.

Changes in mobility of hazardous elements during coal combustion in Santa Catarina power plant (Brazil)

This paper reports about changes in mobility of hazardous elements contained in coal during combustion at a power plant in Santa Catarina (Brazil) and the environmental impact potential of ashes. Total and mobile element concentrations were determined by digestion and sequential extraction. Comparison of results within the mobile fraction showed that after combustion, oxidizable elements bound to organic matter and sulfides in coal were mostly transformed into elements easily soluble in water or slightly acidic conditions and, hence, most readily bioaccumulative in the environment in ashes, mainly U, Cr, and As. Capacity of ashes as a source of mobile pollutants was quantified by combining sequential extraction and annual production. Just considering the easily soluble fraction, coal ashes could leach up to 839tons of Al, 144tons of Fe, 100tons of Mn, 4.6tons of Zn, 3.1tons of Cr, 1.7tons of As, 1.5tons of Cu, 490kg of U, and 20kg of Pb every year. Bottom ashes are disposed of in landfill sites close to the plant. Fly ashes are recycled as construction material. Diagnostic processes do not consider checking for these highly mobile hazardous elements. Hence, uncontrolled dumping and use of these by-products may pose significant risks to environment and human health.

Phosphorus Fertilization Increased Macronutrient Concentrations in Leaves of Stockpiled Tall Fescue

Beef producers utilize stockpiled tall fescue (Festuca arundinacea Schreb. 'Kentucky 31') in the Midwest to extend the grazing season and reduce winter feeding costs. Previous studies indicated concentrations of some macronutrients in stockpiled tall fescue leaves were below those required by lactating beef cows in late winter and early spring. Our previous studies found P fertilization in late winter increased leaf Mg and Ca concentrations in early spring. Therefore, the objective of this study was to determine the effects of 2 years of P fertilization on leaf macronutrient concentrations of stockpiled tall fescue during late fall, winter, and early spring. Leaf concentrations of P, Mg, and Ca were higher with P fertilization than those of the untreated controls. During the second year, the highest P treatment maintained leaf P and Mg concentrations above the critical 0.2% required by lactating beef cows during peak lactation. The leaf concentrations of phloem mobile macronutrients declined from October to February with the exception of N, which reached its lowest concentration in January. Decreases in leaf concentration of mobile elements like P, Mg, N, and K may be the result of nutrient remobilization from leaves to roots during late fall and early winter as a strategy to provide support for next spring's growth. Producers should account for the possibility of low leaf macronutrient concentrations in tall fescue during late winter, especially when beef cattle are grazing pastures on soils with low plant-available P.

Use of Poisoned Land/Inland Seas for Low Level Radioactive Waste Disposal

It is widely known that certain areas of the earth are characterized by such high concentrations of toxic elements that their use by plants or animals is precluded. A water hole whose water contains potentially toxic quantities of As is a common example of such a naturally poisoned area. The dry salt basins of the Basin and Range Province in Nevada and western Utah are largely relict inland salt seas and, because many of the salt basins have total interior drainage of both surface and ground water, these basins represent unique geochemical environments for the entrapment and concentration of mobile elements. Through leaching, transport, and ultimate deposition from throughout the water shed, the closed salt basins are hydrologic sinks in which toxic materials such as As, Sb, Hg, and other heavy metals become concentrated in a relatively confined area.