Total Mn Research Articles

Dissolution of metals in NCM622 cathode through the Dissimilatory process with Na-lactate by Shewanella putrefaciens

Objectives:The objective of this study is to confirm the possibility of reduction and consequent dissolution of Li, Ni, Co, and Mn from NCM622 cathodes in spent Li-ion batteries through the anaerobic respiration with Na-lactate by Shewanella putrefaciens.Methods:The method involves using anaerobic microbial respiration to mimic dissimilatory metal oxide reduction, allowing metals to be leached from NCM622 cathodes (LiNi0.6Co0.2Mn0.2O2) under near-neutral pH conditions (~7.5).Results and Discussion:The results show that approximately 26 wt% of the total Li, Ni, Co, and Mn were successfully leached into the solution within two weeks. This approach differs significantly from conventional acidic leaching processes, offering a more environmentally friendly and sustainable alternative. In addition, we provide quantitative information regarding the dissolution of NCM622 when it is exposed in environmental systems.Conclusion:In conclusion, microbial-based metal leaching presents a novel, sustainable pathway for recovering metals from spent Li-ion batteries, addressing environmental concerns and reducing dependence on traditional energy-intensive recovery methods.

Welding techniques and manganese concentrations in blood and brain: Results from the WELDFUMES study

This study used whole-brain mapping to investigate the effect of different welding processes on manganese (Mn) accumulation in the brain. Exposure measurements were performed at the welders’ workplaces about 3 weeks before a magnetic resonance imaging (MRI) examination. The welders were categorized into three main groups based on welding method, and the T1-relaxation rate (R1) was measured using quantitative MRI (qMRI). Welders using shielded metal arc welding (SMAW) were found to have lower accumulations of total Mn in clusters encompassing white matter, thalamus, putamen, pallidum, and substantia nigra compared with welders using inert gas tungsten arc welding (GTAW) or continuous consumable electrode arc welding (CCEAW). A positive correlation was found between Mn in red blood cells (Mn-RBC) and R1 in a region encompassing pre-and post-central gyri. The results of this study show that the accumulation of free, bound, or compartmentalized Mn ions in the brain differed depending on the welding method used. These differences were predominately located in the basal ganglia but were also found in regions encompassing white matter. The level of Mn-RBC was correlated to the deposition of Mn in the left primary somatosensory and motor cortex and may therefore be linked to neurological and neurobehavioral symptoms.

Micronutrient and heavy metal bioaccumulation in Bermuda grass (Cynodon dactylon L. Pers) grown in calcareous soil using stabilized and dried sewage sludge

This study examines the micronutrients and heavy metal bioaccumulation in Bermuda grass (Cynodon dactylon L. Pers), grown in two different types of calcareous soil (CS) with the application of stabilized and dried sewage sludge (SS). At the end of the growth period, the Fe, Zn, Mn and Cu (micronutrients) concentrations in the substrate have increased. Furthermore, it was determined that the total Fe, Zn, Mn and Cu concentrations were higher in CS1 compared to CS2. For the heavy metals the concentrations of Ni and Cr have increased, and the concentration of total Cd has slightly but significantly decreased. The total Pb concentration was below the detection limit (DL for Pb <0.03 mg kg-1). It was determined that the total Ni, Cr and Cd concentrations were higher in CS1 than in CS2. In the aerial biomass of the Bermuda grass, the Fe and Zn concentrations have increased with increasing SS applications, whereas Mn concentrations have decreased. Ni, Cr, Cd and Pb concentrations were unaffected by SS applications for both types of CS. The bioconcentration factor (BCF) values for the shoot of the plant (BCFFe, BCFZn, BCFMn, BCFCu, BCFNi, BCFCr, BCFCd) were determined to be below the critical limit of 1. The application of sewage sludge has not resulted in bioaccumulation above critical limits in the shoot of the plant. However, considering Bermuda grass substrate, it can be suggested to add sewage sludge to the calcareous soil in amounts between 20–40 t ha-1, considering its long-term remanence.

Frequencies of chromosomal aberrations and related biochemical parameters in welders

Stainless steel welders are exposed to heavy filler metals. We evaluated the concentration of these metals in whole blood and urine, and the relevant biochemical parameters in relation to the total chromosomal aberrations (CAs), chromatid-type (CTA-type, CTAs) and chromosome-type (CSA-type, CSAs), in 117 welders and control individuals. Statistically higher concentrations of the total Cr, Ni and Mn were observed in whole blood and urine of welders, and the concentrations were higher in welders who smoked. On the contrary, concentrations of urinary heavy metals Cr and Mn adjusted for creatinine were significantly higher in the control groups. A statistically higher frequency of total CAs was observed in the whole group of welders, and also in the non-smoking welders, as compared to controls. The frequency of total CAs significantly correlated with the concentration of Cr, Ni and Mn in whole blood (R=0.61, P˂0.0001, R=0.33, P˂0.0001 and R=0.66, P˂0.0001, respectively), with urinary concentrations of Ni and Mn (R=0.27, P=0.003 and R=0.28, P=0.003, respectively) and with urinary concentrations of Cr, Ni and Mn adjusted for creatinine (R=0.22, P=0.029, R=0.26, P=0.005 and R=0.20, P=0.030, respectively). Likewise, the frequency of CTA-types significantly correlated with the concentration of Cr and Mn in whole blood (R=0.31, P=0.0007 and R=0.34, P=0.0002). The frequency of CSA-types significantly correlated with concentrations of Cr, Ni and Mn in whole blood (R=0.43, P˂0.0001, R=0.38, P˂0.0001 and R=0.46, P˂0.0001, respectively). The statistically higher values of serum creatinine and total bilirubin were detected in all welders, as well as in smokers when compared to the corresponding controls. The exposure to heavy metals in welders increased the frequencies of CAs and altered the balance between urinary excretion of heavy metals and their possible accumulation.

Heavy metal contamination and human health risk assessment in the soils grown field crops in Antalya, Türkiye

ABSTRACT Soil pollution results from heavy metals has become a severe environmental concern. Heavy metals pose a risk to human health by entering the food chain. The aim of this study was to determine the concentrations, sources and potential ecological and human health risks of heavy metals in soils which grown field crops in Antalya, Turkey. Soil samples were collected at depths of 0–30 cm from 292 fields and concentrations of cadmium (Cd), lead (Pb), nickel (Ni), chromium (Cr), cobalt (Co), iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) were determined. The mean concentrations of total Cd, Pb, Ni, Cr, Co, Fe, Mn, Cu and Zn were 4.73, 68.67, 152.74, 98.52, 24.77, 28098, 823, 42.72 and 62.85 mg kg−1, respectively. These results showed that the average concentrations of Cd, Pb, Ni, Cr, Co, Cu and Mn exceeded the Upper continental crust average. Enrichment factor (EF), geo-accumulation index (I geo) and contamination factor (CF) values of soils indicate serious enrichment for Cd. Principal component analyses (PCA) indicated that Co, Cr and Ni was lithogenic origins, but Fe and Pb concentrations were determined by lithological and anthropogenic sources. Hazard index (HI) values of heavy metals were < 1, suggesting that non-carcinogenic health risks to adult residents. In addition, the total carcinogenic risk (TCR) values except for Cr, suggesting that carcinogenic risks for residents were not expected. The results showed that children were more sensitive to the non-carcinogenic and carcinogenic effects of heavy metals.

Impact of Twig-Tip Dieback on Leaf Nutrient Status and Resorption Efficiency of Mango (Mangifera indica L.) Trees

Mineral nutrition is essential for plant growth and the interaction of plants with biotic and abiotic stresses. Mango twig-tip dieback (MTTD) is a new type of mango decline, but its impact on trees’ mineral nutrition is unknown. This study was conducted to determine the effect of MTTD infection on the nutrient status, balance, and resorption efficiency (RE) of mangoes. Leaf nutrient concentrations and deviation from the optimum percentage (DOP) indices of ‘Kensington Pride’ (KP) mango trees with low (LD) and high (HD) levels of MTTD infections were analyzed to compare the foliar nutrition status and nutrient balance between the LD and HD trees. Moreover, the nutrient resorption efficiency of MTTD-infected dried leaves (RED) was compared with the resorption efficiency of healthy (RES) leaves of KP mangoes. The concentrations of total Ca, Mg, Cu, Fe, Mn, and Zn were lower in the HD trees than in the LD trees. But the total K content was higher in the HD trees, and its DOP index was sufficient, while the total K concentration was of a low and deficient level in LD trees. Moreover, the DOP indices for total Ca, Mn, and Zn were less deficient in LD trees than in HD trees, and the overall nutrient imbalances were exacerbated in HD trees. The RED was significantly lower than RES for the total N, P, S, Cu, Fe, and Zn but significantly higher than RES for K. This study underscores the significant influence of MTTD on the mineral nutrition of KP mangoes, revealing distinct nutrient variations between trees with low and high MTTD infection levels. These findings have important implications for mango crop management, emphasizing the need for targeted nutrient interventions to address imbalances induced by MTTD and enhance the overall health and resistance of mango trees against MTTD infections.

Total and Extractable Micronutrients in Tropical Acid Soils of Lampung, Indonesia

ABSTRACT The study aimed to determine the total and available amounts of iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) in the humid tropical acid soils of Lampung, Indonesia, and to identify the key factors affecting them. Topsoil samples were taken from 10 agricultural fields and 6 natural fields in 16 sub-districts of Lampung, Indonesia. The average total contents of Fe (26.36 g kg−1), Cu (8.97 mg kg−1), and Zn (53.24 mg kg−1) are generally below the world-soil average contents and those in other acid soils, which may be due to eluviation of Fe, Cu, and Zn into subsoil induced by high rainfall and the low natural contents of especially Cu and Zn in the parent rocks (acid volcanic rocks and sandstone). In contrast, the average total Mn content (1.20 g kg−1) is 2 to 8 times higher than that commonly found in acid soils and the world-soil average content, indicating that the parent materials may contain high Mn-bearing minerals. The total Fe, Mn, and Zn are positively correlated to the clay content, exchangeable-Ca and -Mg, and exchangeable-Mg, respectively, whereas the total Cu has no correlation to any soil properties. The amounts of available Fe, Mn, Cu, and Zn account for on average 0.38%, 6.20%, 21.50%, and 4.40% of the total contents, respectively. Around 6%, 12.5%, and 56% of the soil samples exhibit Mn, Cu, and Zn deficiency, respectively, and 25% face Fe toxicity. Total Fe and Mn are the main factors determining available Fe and Mn, respectively, whereas exchangeable-Mg and organic-C content mainly control available Cu and Zn, respectively.

Occurrence, transport and sources of metals and metalloids in the Bangpakong River in the eastern economic corridor area of Thailand

The occurrence of elements in river water is affected by various factors, including mobility, weathering and transport processes and anthropogenic contributions. A total of six water sampling campaigns were conducted from 2021 to 2022 to study the factors affecting the occurrence of twelve elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Se) in the Bangpakong River. The total concentrations of all the elements were within the levels set by the national surface water quality standard. Comparisons of dissolved elemental concentrations in the study area with the global average for dissolved elemental concentrations in pristine rivers indicated contamination with Al, As, Co, Mn, Zn and Se in the river water. Based on the percentage of each element in particulates to the total concentration, Al (80.6 %), Cr (71.9 %), Cu (69.9 %), Fe (95.6 %), Mn (76.6 %), Pb (74.7 %), and Zn (70.6 %) were mainly transported in the particulate phase in both the dry and wet seasons. However, As (65.5 %), Co (60.3 %), and Se (77.6 %) were mainly transported in the dissolved phase in both seasons. The ratios of the dissolved Se concentration in river water to the Se concentration in the Earth's crust indicated significant and high mobility, especially in downstream sites, likely due to Se leaching from alluvial sediments. Seawater intrusion is likely the cause of As and Zn contamination in the dry season. Weathering of rocks and soils likely causes Al, Co, and Mn contamination in the wet season. The anthropogenic sources of contamination include the discharge of Mn and Zn from fertilizers in agriculture and the use of formulated feed in aquaculture. Approximately 52.98, 25.23, 5.68 and 0.63 tons of Fe, Al, Mn and Zn, respectively, are estimated to be transported from the river into the Gulf of Thailand each year.

Advances in assessing Ca, K, and Mn translocation in oak tree stems (Quercus spp.)

As a part of the biogeochemical cycle, nutrient translocation plays an important role in enhancing the capacity of perennial plants to grow in nutrient-poor soils. Although leaf translocation has been extensively studied, nutrient translocation between wood rings has received considerably less attention, primarily because of methodological constraints. This study aimed to (i) evaluate the effects of different drying techniques on Ca, K, and Mn concentrations, (ii) calibrate a semi-quantitative method for obtaining ring-to-ring nutrient concentrations along wood cores, and (iii) develop a complete calculation chain for nutrient translocation. Three pairs of cores per tree were extracted from nine oaks, and three drying methods—103 °C, 65 °C, and freeze-drying—were applied to each core pair. For each core pair, the first core was analyzed using ITRAX. The second core was analyzed using ICP-OES following the mineralization of a 20 mg wood sample. Ca, K, and Mn concentrations and wood density were not affected by the drying methods (p > 0.05 for Ca, K, and Mn). After upscaling at the stand level, the total translocation was 10.8 ± 5.5 kg ha−1, 14.8 ± 11.4 kg ha−1, and 2.6 ± 0.9 kg ha−1 for Ca, K, and Mn, respectively, after 45 growing years. The total Ca, K, and Mn translocation showed a strong tree effect, partly explained by tree diameter. The study findings suggest that similar measurements can be performed on all wood cores sampled in previous studies and stored after air-drying. These results provide a reference for future analyses of Ca, K, and Mn translocations in different species from wide geographic areas.

Influence of Mulberry Leaf Powder Additive on Chemical and Physical Characteristics of Wheat and Rice Flour Butter Cookies.

People of all age groups consume cookies every day. Consumers' preferences for cookies supplemented with functional plant raw materials have recently increased. Therefore, this research aimed to investigate the influence of a mulberry leaf additive on the proximate and mineral compositions, total phenolic and total chlorophyll content, antioxidant activity, and the hardness and color properties of butter cookies. Wheat and rice flour butter cookies were prepared by replacing the flour with mulberry leaf powder at 0, 4, 8, and 12% (w/w). The results revealed that the investigated chemical and physical characteristics of butter cookies depend on the flour used (rice or wheat) and the addition of mulberry leaf powder. Wheat and rice flour cookies with 12% mulberry leaf powder had the significantly highest contents of fiber (20.34 and 20.23%, respectively), ash (1.73 and 1.75%, respectively), K (170.22 and 160.22 mg 100 g-1, respectively), and Ca (170.45 and 160.68 mg 100 g-1, respectively). The rice flour cookies enriched with 12% leaf powder had the greatest amounts of total phenolics (1.48 mg 100 g-1), Zn (12.25 mg kg-1), Mn (6.28 mg kg-1), Cu (1.95 mg kg-1), and antioxidant activity (67.98%). However, the wheat cookies without mulberry leaf powder contained the most B (9.12 mg kg-1), while the no-added rice cookies contained the most Fe (14.30 mg kg-1). Replacing flour with leaf powder increased the cookies' hardness and decreased their lightness. In conclusion, enriching butter cookies with freeze-dried mulberry leaves can improve their nutritional value and antioxidant activity.

Advances in the Sustainable Production of Fertilizers from Spent Zinc-Based Batteries

Wastes from spent batteries are a secondary source of raw materials. To ensure this, it is mandatory to design sustainable and low-cost processes. In the case of alkaline and zinc–carbon-based batteries, the high content of Zn and Mn makes them of interest in the development of fertilizers. The main objective of this research is to study the fertilizers production from spent zinc-based batteries, using sulfuric acid, citric acid (CIT) and glycine (GLY) solutions as leaching agents. Leaching with glycine at alkaline pHs shows a high selectivity of Zn over Mn, whereas the use of citric and sulfuric solutions leads to recoveries of Zn and Mn. Solutions with the highest Zn recoveries were tested in sand columns. Commercial ZnSO4 heptahydrate was used as a control. For sulfuric acid, two solutions (H2SO4 2M and 0.25M) were used. The elution of leached Zn and Mn in sand columns depended on the solution added. The Zn-Mn-CIT treatment showed a slight but steady increase in the leachates, reaching 70% and 75% of the total leached Zn and Mn, respectively, in the medium term. The Zn-Mn-H2SO4 2M and ZnSO4 treatments showed a similar behavior in Zn release. Both Zn-Mn-GLY and Zn-Mn-H2SO4 0.25M treatments showed similar amounts of leached Mn in the medium term (77% of total leached Mn), differing in the leached Zn. Solutions from the leaching of spent black mass batteries, especially Zn-Mn-CIT or Zn-Mn-GLY, showed promising behavior as fertilizer from the point of view of Zn and Mn availability as nutrients.

Potential ecological and human health risk assessments of soil heavy metals in orchards of Antalya province in Türkiye

ABSTRACT Agricultural inputs containing heavy metals are used intensively in Türkiye. However, studies on the assessment of the effects of heavy metals on the environmental and human health risks of agricultural areas in Türkiye are very limited. The aim of this study was to determine the concentrations, sources and potential ecological and human health risks of heavy metals in soils from orchards in Antalya, Türkiye. A total of 127 soil samples were collected and analysed for cadmium (Cd), lead (Pb), nickel (Ni), chromium (Cr), cobalt (Co), iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn). The mean concentrations of total Cd, Pb, Ni, Cr, Co, Fe, Mn, Cu and Zn were found to be 4.54, 64.68, 145.80, 94.00, 23.92, 28264, 763.30, 44.91, and 63.67 mg kg−1, respectively. The mean concentrations of Cd, Co, Ni, Pb, Cu and Mn of soils were higher than the European soil mean values. Enrichment factor (EF) and contamination factor (CF) values of soils indicate serious enrichment for Cd, Pb and Ni. According to the principal component analysis, Cd concentration in the soil from was anthropogenic sources, Ni, Cr and Pb from both anthropogenic and lithogenic origin while other heavy metals from natural sources. Total hazard index (THI) values of heavy metals were <1, suggesting that there were currently absent non-carcinogenic health risks to residents through ingestion, inhalation and dermal contact. Hazard index (HI) indicated that children (3.75) were sensitive 9.4 times more than adults (0.40) to non-carcinogenic risks of heavy metals. The carcinogenic risk values of Cd, Cr, Co and Ni were acceptable range and not expected carcinogenic risks.

A method for studying the influence of Mn oxyhydroxides on the trace element content of aquatic bryophytes

The main objective of this study was to develop and test a method of separating externally deposited Mn oxyhydroxides and co-precipitated elements from samples of aquatic moss (the moss Fontinalis antipyretica). The method, which uses 0.1 M hydroxylamine to dissolve the oxyhydroxides, was tested with samples collected in rivers with slightly acidic, well‑oxygenated waters, where high rates of Mn precipitation occur. The method was effective (it extracted up to 84 % of the Mn) and selective (Fe oxyhydroxides were not extracted). The elements Ba, Cd, Zn and Ni were associated with the Mn oxyhydroxides, while Al, As, Cr, Cu, Fe, Hg and Pb were not. Deposition of Mn therefore increased the concentration of some elements in the moss samples. However, as Mn precipitation depends on Eh and pH, which are independent of the concentrations of the elements in water, the relationship between water and moss element concentrations is not clear (i.e. the data are noisy). This is a problem in biomonitoring studies, which assume a close relationship between element concentrations in moss and water. The value of the proposed extraction method is that it can be used to correct the effect of Mn deposition. We present an example of this correction applied to the Cd concentrations in the test data. We found that the noise introduced by the Mn, including age-related effects (observed by comparing concentrations in 0–2.5 and 2.2–5.0 cm sections from the shoot apex), can be reduced. Additionally, the correction revealed recent increases in Cd concentrations in one site that were not observed in the uncorrected data. Another finding of interest was the low content of total Mn and different extractability (of most elements) observed in moss samples collected in alkaline waters. Finally, we discuss how future studies designed for different environmental scenarios can benefit from application of the proposed method.

Divergent redistribution behavior of divalent metal cations associated with Fe(II)-mediated jarosite phase transformation

The Fe(II)/Fe(III) cycle is an important driving force for dissolution and transformation of jarosite. Divalent heavy metals usually coexist with jarosite; however, their effects on Fe(II)-induced jarosite transformation and different repartitioning behavior during mineral dissolution-recrystallization are still unclear. Here, we investigated Fe(II)-induced (1 mM Fe(II)) jarosite conversion in the presence of Cd(II), Mn(II), Co(II), Ni(II) and Pb(II) (denoted as Me(II), 1 mM), respectively, under anaerobic condition at neutral pH. The results showed that all co-existing Me(II) retarded Fe(II)-induced jarosite dissolution. In the Fe(II)-only system, jarosite first rapidly transformed to lepidocrocite (an intermediate product) and then slowly to goethite; lepidocrocite was the main product. In Fe(II)–Cd(II), -Mn(II), and -Pb(II) systems, coexisting Cd(II), Mn(II) and Pb(II) retarded the above process and lepidocrocite was still the dominant conversion product. In Fe(II)–Co(II) system, coexisting Co(II) promoted lepidocrocite transformation into goethite. In Fe(II)–Ni(II) system, jarosite appeared to be directly converted into goethite, although small amounts of lepidocrocite were detected in the final product. In all treatments, the appearance or accumulation of lepidocrocite may be also related to the re-adsorption of released sulfate. By the end of reaction, 6.0 %, 4.0 %, 76.0 % 11.3 % and 19.2 % of total Cd(II), Mn(II), Pb(II) Co(II) and Ni(II) were adsorbed on the surface of solid products. Up to 49.6 %, 44.3 %, and 21.6 % of Co(II), Ni(II), and Pb(II) incorporated into solid product, with the reaction indicating that the dynamic process of Fe(II) interaction with goethite may promote the continuous incorporation of Co(II), Ni(II), and Pb(II).

Eastern Canadian boreal forest soil and foliar chemistry show evidence of resilience to long-term nitrogen addition.

The boreal forest is one of the world's largest terrestrial biome and plays crucial roles in global biogeochemical cycles, such as carbon (C) sequestration in vegetation and soil. However, the impacts of decades of N deposition on N-limited ecosystems, like the eastern Canadian boreal forest, remain unclear. For 13 years, N deposition was simulated by periodically adding ammonium nitrate on soils of two boreal coniferous forests (i.e., balsam fir and black spruce) of eastern Canada, at low (LN) and high (HN) rates, corresponding to 3 and 10 times the ambient N deposition, respectively. We show that more than a decade of N addition had no strong effects on mineral soil C, N, P, and cation concentrations and on foliar total Ca, K, Mg, and Mn concentrations. In organic soil, C stock was not affected by N addition while N stock increased, and exchangeable Ca2+ and Mg2+ decreased at the balsam fir site under HN treatment. At both sites, LN treatment had nearly no impact on foliage and soil chemistry but foliar N and N:P significantly increased under HN treatment, potentially leading to foliar nutrient imbalance. Overall, our work indicates that, in the eastern Canadian boreal forest, soil and foliar nutrient concentrations and stocks are resilient to increasing N deposition potentially because, in the context of N limitation, extra N would be rapidly immobilized by soil micro-organisms and vegetation. These findings could improve modeling future boreal forest soil C stocks and biomass growth and could help in planning forest management strategies in eastern Canada.

Differences in soil chemistry between early and late succession of oak-hornbeam forest after grassland abandonment

Changes in C and nutrient cycling during succession are well studied, however, results can be contrasting for different nutrients and successional sequences. We analyzed soil chemical differences between early and late succession of oak-hornbeam forest. Late forest succession efficiently retained plant-available P, and total Mn, Zn, Fe, Cu, and Ni pools in the soil, as their concentrations were similar to those of early-successional grasslands. Available K, soil organic C, and organic matter content, as well as C:N and C:S ratios were higher in late than in early succession. Soil organic N and S concentrations did not differ between the stages.

MIGRATION OF HEAVY METALS FROM MINE WASTE ROCK DUMP END ENVIRONMENTAL IMPACT ON GROUNDWATERS AND SEDIMENTS

The environmental impact of mine waste rock dump, located in the region of Srednogorie, Bulgaria on groundwaters and sediments was studied. The acid mine drainage with low pH (2.43 - 3.53), high electrical conductivity (1500 - 4400 μS cm-1), content of Fe, Mn, Cu, Zn, Al, As and high concentration of sulfates (540 - 6905 mg L-1) are formed after heavy rainfall. The content of heavy metals, except manganese, in groundwater was significantly lower than that in the acid mine drainage, and the pH was in the range of 5.43 to 6.62. Sediments in the non-consequential vicinity of the mine waste rock dump had a pH in the range of 2.86 - 4.53 and contained heavy metals and As at concentrations higher than those in the mineral waste due to precipitation, co-precipitation and sorption reactions. An increase in the copper and zinc content in the exchangeable and organic matter fractions was found in the sediment sample. A relationship was found between arsenic and iron concentration in the sediments, which was mainly due to the retention of arsenic in the Fe and Mn oxides fraction. The concentration of total Mn in the sediments was lower than that in the mining waste due to the high mobility of manganese.

Factors regulating lignocellulolytic microbes, their degrading enzymes, and heterotrophic respiration in oil palm cultivated peatlands

Even though their role in mediating tropical peat decomposition and GHG emissions had been widely recognized, information concerning lignocellulolytic microbes, their degrading enzyme ability, and interconnection with soil physicochemical properties and peat heterotrophic respiration on mature oil palm plantation/OPP block level were rudimentary. This study evaluated the effect of sampling depth (0-30, 30-60, and 60-90 cm), OPP management zone (fertilization circle/FTC, frond stack/FRS, and harvesting path/HVP), and peat physicochemical properties on the lignocellulolytic bacteria and fungi, their degrading enzymes activities and peat heterotrophic respiration/Rh using principal component analysis/PCA, multiple linear regression/MLR, and generalized linear mixed effect models/GLMM. This study found that the soil microbiological and physicochemical properties varied widely. Dominant lignocellulolytic bacterial population and their cellulase enzyme activity were higher than fungi, regardless of sampling depth and management zone. PCA and GLMM analyses showed the significant importance of sampling depth and management zone in governing lignocellulolytic microbial population, their enzyme activities, and Rh. Microbial population and cellulase activity were also remarkably affected by the interaction of all studied factors. Peat chemical properties (pH and total Mn) controlled the natural variance of lignocellulolytic microbes and their enzymes, whereas total K regulate Rh. This study suggested that the research on microbiological-related GHG mitigation in OPP should be focused on managing the fungal population and cellulase enzyme activity at the peat surface (0-30 cm) and fertilization circle.

Soil Quality Index for Different Cropping Systems in Northwestern Himalaya Region of India

Background: A study was conducted to examine the impact of soil quality under different cropping systems in Mid hill conditions of Himachal Pradesh”. The study was carried out to ascertain the physical, chemical and biological properties of soils under prevalent cropping systems maize- wheat, rice- wheat and vegetable based in different in mid hill conditions of northwestern Himachal Pradesh.&#x0D; Methods: On the basis of representative 90 soil samples from two depths i.e. 0-0.15 m and 0.15-0.30 m were collected. Soil samples were analyzed for their physical, chemical and biological properties and key indicators were identified using multivariate statistical analysis for computing the soil quality index.&#x0D; Results: Soil reaction across various sites under present study was 5.30-6.70. Higher salt accumulation (EC) was observed under vegetable based cropping systems as compared to those of cereal based. Organic carbon was medium to high and available N, P and K contents were in low to medium range. DTPA Fe, Mn, Zn and Cu were observed sufficient, whereas total Fe, Mn, Zn and Cu were recorded higher in cereal and vegetable based cropping system. Microbial biomass carbon, microbial biomass nitrogen, potentially mineralizable nitrogen and soil respiration were low to medium in all cropping systems.&#x0D; Conclusion: Soil quality index was 1.00 under vegetable based cropping system as compared to the cereal based cropping systems.

Shortened Sequential Extraction Procedure: An Effective and Time-Saving Determination of Trace Metals Over Sediments

ABSTRACT In this work, the seven-step extraction procedure (SSEP) proposed by our laboratory team was modified to reduce the number of fractions from seven to five (FSEP) without affecting its effectiveness. By this way, the modified SSEP was investigated by comparing the quantity of trace (Cd, Co, Cr, Cu, Ni, Zn) and major (Ca, Fe, Mn) elements leached from two sediments (TH2 and T16). Compared to the SSEP, the shortened sequential test allows to reach the same results in terms of reproductibility. Results confirm that the water-soluble step is negligeable and can be omitted for the sediments. The percentage of the total leached elements Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn were 23%, 13%, 58%, 55%, 92%, 63%, 81%, 65% and 80%, respectively, for both procedures SSEP and FSEP. However, merging the reducible fractions revealed for some elements a little reduction of the leached quantities in comparison to the original SSEP. Over reducible fraction, the leached Fe element in T16, achieves 4% for SSEP and 3% for FSEP. This was explained by the partial dissolution of the amorphous and crystalline irons. Based on the reduced number of fractions, the used extraction filters (28 Vs 20) and the extraction time (18 h Vs 13.5 h), FSEP appeared to be easier for manipulation without loss of its effectiveness. However, the choice of the FSEP must be deduced from the physicochemical properties of the sample and the aim of the envisaged study.