Ppm Pb Research Articles

The effects of developmental sub-chronic low-level lead exposure on microglia and a test of possible mitigation by apigenin in C57BL/6/J young mice

Developmental chronic low-level lead (Pb) exposure disrupts central nervous system function and diminishes neurocognition. Microglial cell activation might contribute to these deficits. The present study evaluated the effects of developmental sub-chronic low-level lead exposure on microglial cells and the possible effectiveness of a natural anti-inflammatory intervention with apigenin to mitigate these effects. From PND 0 to 28, 87 C57BL/6 J mice were exposed to one of six treatment conditions: 0 ppm Pb; 30 ppm Pb; 430 ppm Pb; 30 ppm Pb + 400 ppm apigenin; 430 ppm Pb + 400 ppm apigenin; or 400 ppm apigenin, via dam's drinking water. Following sacrifice, brain tissue was harvested and microglial cells were labeled via immunohistochemistry and counted within the dentate gyrus (DG) using unbiased stereology methods. It was hypothesized that developmental sub-chronic low-level lead exposure would increase microglial cell numbers within the DG and that apigenin treatment may mitigate these effects. A significant effect of treatment group was found and post-hoc analyses revealed that Pb-exposure generated an increased number of microglial cells as compared to controls. Interestingly, the 30 ppm Pb with apigenin treatment group did not generate microglial cell numbers different from the control group unexposed to Pb. These results suggested that developmental sub-chronic low-level lead exposure increased microglial cell activation within the DG and that, at low-levels of Pb exposure, apigenin treatment may mitigate these effects. These results provided the groundwork for studies that could identify an effective intervention to alleviate the effects of developmental chronic low-level lead exposure in child neurocognition.

Metallic Impurities in Electrolysis: Catalytic Effect of Pb Traces in Reductive Amination and Acetone Reduction.

The electrochemical hydrogenation (e-hydrogenation) of unsaturated compounds like imines or carbonyls presents a benign reduction method. It enables direct use of electrons as reducing agent, water as proton source, while bypassing the need for elevated temperatures or pressures. In this contribution, we discuss the active species in electrocatalytic reductive amination with the transformation of acetone and methylamine as model reaction. Surprisingly, lead impurities in the ppm-range proved to possess a significant effect in e-hydrogenation. Accordingly, the influence of applied potential and cathode material in presence of 1 ppm Pb was investigated. Finally, we transferred the insights to the reduction of acetone manifesting comparable observations as for imine reduction. The results suggest that previous studies on electrochemical reduction in the presence of lead electrodes should be re-evaluated.

Responses to exogenous elicitor treatment in lead-stressed Oryza sativa L.

Heavy metal toxicity adversely affects plants by changing physiological, biochemical, and molecular mechanisms. Lead (Pb) is one of the most common heavy metal pollutants. Hence this study investigated changes caused by exogenous methyl jasmonate (MeJA; 20 and 100 µM) and salicylic acid (SA; 2 and 20 mM) elicitors in local Karacadağ rice exposed to Pb stress (0, 100, and 400 ppm). The effects of elicitors on photosynthetic pigment content (chlorophyll a, chlorophyll b, and total carotenoid), proline, malondialdehyde (MDA), total phenolic and flavonoid, Pb, and total protein contents in stressed plants were evaluated. All parameters studied increased and decreased at varying rates in the treatment groups compared to the Pb-free group (control), indicating that rice plants were affected by Pb stress. The elicitors (MeJA, SA, and MeJA + SA) were applied by foliar spraying. The elicitor treatments increased photosynthetic pigment content, total protein, proline, total flavonoid, and phenolic contents depending on the elicitor type and concentration. MDA and Pb contents, increasing with Pb toxicity, decreased with elicitor treatments, and the stress degree was reduced. When the elicitors were compared, SA was more effective than MeJA in total flavonoid content at 400 ppm Pb toxicity. However, MeJA was more effective in photosynthetic pigment contents, MDA, total protein, Pb, total phenolic, and proline contents. The best results for all parameters examined in rice plants exposed to Pb toxicity were obtained from the 400 ppm Pb + 2 mM SA + 20 µM MeJA treatment group. In conclusion, this study showed that the combined application of MeJA + SA alleviated the harmful effects of Pb by reducing MDA and increasing photosynthetic pigments, total protein, proline, and secondary metabolites, especially at high Pb concentrations. Consequently, this study demonstrated that the combined use of MeJA and SA in rice plants eliminated the negative effects of stress quite effectively, even at high Pb concentrations. Therefore, future studies should focus on the synergistic application of different elicitors to better understand the effects of heavy metal toxicity on plant growth and development.

Adsorption of Pb(II) ions using a biosorbent derived from pineapple peel

Abstract The potential of pineapple peel as a biosorbent for a heavy metal, Pb(II), was investigated. The experiment was carried out at various contact times, doses of adsorbent, and pH of the solution. Results obviously showed that pineapple peel biosorbent has potential for removing Pb(II) ions from aqueous solutions. The adsorption of Pb(II) ions depended on the pH of the solution. No significant difference was observed when the adsorption was performed at pH of 4.0 and 5.0. The scanning electron microscope (SEM) evaluation indicated that the surface of pineapple peel (PP) biosorbent is arranged like flakes and fractures, in addition some pores are also present. The biosorbent made from pineapple peel showed a cloud-like layer in the SEM image after adsorption, showing that the Pb(II) ions were successfully adsorbed. About >90% of 100 ppm Pb(II) ions were adsorbed within 5 minutes, indicating that the biosorbent derived from pineapple peel has a fast adsorption capacity. In conclusion, our investigation clearly showed the potential of biosorbent-derived pineapple peel to remove heavy metals, including Pb(II) ions, from solutions.

Spraying or fertigation? looking for the better method in terms of the lower concentration of Pb and Ni in greenhouse cucumber.

This study was conducted to investigate the status of Lead (Pb) and Nickel (Ni) in greenhouse cucumber affected by fertigation and spraying as a factorial split plot arrangement based on a randomized complete block design (RCBD) with three replications at Soil and Water Research Institute, Karaj, Iran in 2023. The main and sub-plots were respectively fertigation and spraying that was applied in two levels [the minimum permissible concentration of these metals in granular triple super phosphate fertilizer (five ppm Pb and five ppm Ni) as the control treatment, and the maximum permissible concentration of Pb and Ni in granular triple super phosphate fertilizer (50 ppm Pb and 100 ppm Ni)]. Spraying was done in three modes (spraying leaves, leaves + fruit, and fruit). Based on the results, the highest concentration of Pb in the fruit (fruit peel + fruit flesh) (0.295 mg/kg DW) was recorded in the fertigation + spraying with the maximum permissible concentrations of Pb and Ni treatments. A general comparison between the two fertilization methods showed that the sprayingmethod accumulated a higher concentration of Pb in the fruit (i.e., peel + flesh) than the fertigation method. The reverse of this status happened for Ni, so the fertigation method accumulated a higher concentration of Ni in the fruit (skin + flesh) compared to the spraying method. On average, the order of Pb concentration in different organs was as follows: leaf (0.765mg/kg) > fruit peel (0.232mg/kg) > fruit peel + flesh (0.174mg/kg) > fruit flesh (0.129mg/kg). This order for Ni was as follows: fruit flesh (0.597mg/kg) > fruit peel + flesh (0.345mg/kg) > leaf (0.3mg/kg) > fruit peel (0.175mg/kg). These orders show that the status of the heavy metals in plant tissues is related to the nature of the metal, the type of the organ, and the method of fertilization.

Bioremoval of Pb2+ by Aspergillus niger D1RA, A heavy metal-resistant fungus isolated from an illegal gold mining site

Abstract. Nofiani R, Mu’in R, Hafizah, Ardiningsih P. 2024. Bioremoval of Pb2+ by Aspergillus niger D1RA, A heavy metal-resistant fungus isolated from an illegal gold mining site. Biodiversitas 25: 2504-2511. Heavy metal pollution can cause serious problems for the environment and human health. One of the methods to eliminate this pollution is to use heavy metal-resistant fungi isolated from heavy metal-polluted environments. This study aimed to investigate the ability of heavy metal-resistant fungi to remove Pb2+ in liquid media, Potato Dextrose Broth (PDB). Samples were collected from two locations, namely an abandoned illegal gold mining site and illegal gold mine, Samalantan, Bengkayang District, West Kalimantan, Indonesia. Each sample was inoculated on two different agar media (PDA= Potato Dextrose Agar and MEA= Malt Extract Agar) supplemented with 7.5 ppm HgCl2. All fungal species that grew on the surface media were isolated, identified (based on spore morphology and Internal Transcribed Spacer [ITS]), evaluated (tolerance index [TI] against Hg2+, Pb2+, and Zn2+), and assessed for their bioaccumulation capacity and Pb2+removal efficiency. Four isolates (Aspergillus sp. OK2A, Aspergillus sp. OEA, Aspergillus sp. OEB and OEC) were successfully isolated from the abandoned illegal gold mine, while only one isolate (Aspergillus niger D1RA) was isolated from the illegal gold mining site. On the eighth day of incubation, the high tolerance level of each fungus to various selected metal concentrations was Aspergillus sp. OK2A in 40 ppm HgCl2 and 300 ppm ZnCl2; Aspergillus sp. OEA in 40 ppm HgCl2 and 1,200 ppm ZnCl2; Aspergillus sp. OEB in 800 ppm Pb(NO3)2; OEC in 20 ppm HgCl2; A. niger D1RA in 40 ppm HgCl2, 1,200 ppm Pb(NO3)2, 300 ppm ZnCl2. Only A. niger D1RA showed a high tolerance for three metals and was further analyzed to determine the bioaccumulation capacity and removal efficiency of Pb2+. The best bioaccumulation capacity and removal efficiency of Pb2+ in PDB medium supplemented with 100 ppm Pb(NO3)2 at pH 4 were 237.776 mg/g dried biomass and 93.266 %, respectively. In conclusion, A. niger D1RA has the potential as a bioremediation agent to remediate Pb2+ environments.

Demyelination and impaired oligodendrogenesis in the corpus callosum following lead exposure.

The corpus callosum is an oligodendrocyte-enriched brain region, replenished by newborn oligodendrocytes from oligodendrocyte progenitor cells (OPCs) in subventricular zone (SVZ). Lead (Pb) exposure has been associated with multiple sclerosis, a disease characterized by the loss of oligodendrocytes. This study aimed to investigate the effects of Pb exposure on oligodendrogenesis in SVZ and myelination in the corpus callosum. Adult female mice were used for a disproportionately higher prevalence of multiple sclerosis in females. Acute Pb exposure (one ip-injection of 27 mg Pb/kg as PbAc2 24 hr before sampling) caused mild Pb accumulation in the corpus callosum. Ex vivo assay using isolated SVZ tissues collected from acute Pb-exposed brains showed a diminished oligodendrogenesis in SVZ-derived neurospheres compared with controls. In vivo subchronic Pb exposure (13.5 mg Pb/kg by daily oral gavage 4wk) revealed significantly decreased newborn BrdU+/MBP+ oligodendrocytes in the corpus callosum, suggesting demyelination. Mechanistic investigations indicated decreased Rictor in SVZ OPCs, defective self-defense pathways, and reactive gliosis in the corpus callosum. Given the interwined pathologies between multiple sclerosis and Alzheimer's disease, the effect of Pb on myelination was evaluated in AD-modeled APP/PS1 mice. Myelin MRI on mice following chronic exposure (1,000 ppm Pb in drinking water as PbAc2 for 20wk) revealed a profound demyelination in the corpus callosum compared with controls. Immunostaining of the choroid plexus showed diminished signaling molecule (Klotho, OTX2) expressions in Pb-treated animals. These observations suggest that Pb caused demyelination in the corpus callosum, likely by disrupting oligodendrogenesis from SVZ OPCs. Pb-induced demyelination represents a crucial pathogenic pathway in Pb neurotoxicity, including multiple sclerosis.

Mixed lead sources in tin metal: Implications for using lead isotopes to study tin artifacts

Methods for provenancing copper, lead, and silver using the isotopic composition of lead are well-established. Lead isotope analysis holds promise for the study of tin metal as well, as long as one accounts for the U-Th-Pb systematics of cassiterite (SnO2) and chaîne opératoire of tin production. Although Precambrian cassiterite may contain 10s of ppm Pb or more (predominantly radiogenic 206Pb), Phanerozoic examples typically contain only a few parts per million Pb. However, all but one of the 133 raw tin ingots excavated from European Bronze Age shipwrecks contains more Pb than could have come from cassiterite alone, as do six of the twelve analyzed tin objects interpreted to have been derived from the ores of southern Africa. Accordingly, almost all tin objects must contain Pb from external cassiterite sources and interpretation of LIA must account for this contamination. The nature of the contaminant (sulfides, U-Th-bearing minerals, silicates) can be inferred from patterns in Pb concentration and LI values. The 3 major sources of Pb that can typically be identified in tin artifacts are original Pb from the tin ore, radiogenic Pb produced in-situ due to U decay, and external Pb added during the cassiterite smelting and ingot production. As cassiterite has high U/Pb but low Th/Pb, the 208Pb/204Pb may be representative of the initial Pb incorporated in the mineral. This is assuming either that no external Pb is added during the ore processing or that the added Pb is from coeval sulfides from the same Pb ore provenance. In such cases 208Pb/204 Pb can be used to estimate a Pb model age, which in turn can be used for provenance estimate of the ingots. If the addition of Pb is from U-Th-mineral contaminants to the ore concentrate, then this will also increase 208Pb/204Pb and point to erroneously young model Pb ages. In such cases, the problem would be evident in positively correlated values of 206Pb/204Pb and 208Pb/204Pb. If Pb concentrations are above a certain threshold (approximately 5 ppm). LIA typical common Pb isotope ratios will be clear indication that external, non-cassiterite Pb, is added to the tin artifact. This tin could be from impurities in the ore (e.g., inclusions in cassiterite, impurities in the ore concentrate, or added during ore smelting and/or metal processing. Overall, elevated Pb concentrations accompanied with non-radiogenic Pb isotopes typical for common Pb, is a clear indication that significant amount of external (contaminant) Pb is added to the tin artifact.

Utilizing Date Palm Leaf Biochar for Simultaneous Adsorption of Pb(II) and Iodine from Aqueous Solutions

This study addresses the environmental and health hazards posed by Pb(II) and iodine, two significant contaminants. The objective was to explore the adsorption of these substances from aqueous solutions using biochar derived from the leaf midribs of the date palm through a slow pyrolysis process. The pyrolysis was conducted in two stages within a vacuum furnace: initially at 300 °C for 1 h followed by overnight cooling, and then at 600 °C with a similar cooling process. The resulting biochar was characterized for its microstructural features and functional groups using scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. It exhibited a porous structure with large numbers of pores (20 to 50 μm in size) and functional groups including O-H, C-H, and C=C, which are integral to its adsorption capabilities. For the adsorption studies, a 100 ppm Pb(II) ion solution was treated with varying amounts of biochar (20, 40, 60, and 80 mg) for 24 h. In parallel, iodine adsorption was tested, with biochar quantities ranging from 0.1 to 0.4 g/50 mL. Both treatments were followed by filtration and analysis using atomic absorption spectroscopy to determine the remaining concentrations of Pb(II) and iodine. The study also explored the effect of varying incubation periods (up to 30 h) on iodine adsorption. The results were significant; 100% adsorption of Pb(II) was achieved with the addition of 60 mg of biochar per 10 mL of solution. In contrast, for iodine, a maximum adsorption of 39.7% was observed with 30 mg or 40 mg of biochar per 50 mL. These findings demonstrate the potential of date palm-derived biochar as an effective and sustainable material for the removal of Pb(II) and iodine from contaminated water, offering valuable insights for environmental remediation strategies.

Offsetting pb induced oxidative stress in Vicia faba plants by foliar spray of chitosan through adjustment of morpho-biochemical and molecular indices

In the course of their life, plants face a multitude of environmental anomaly that affects their growth and production. In recent decades, lead (Pb) gained an increasing attention as it is among the most significant contaminants in the environment. Therefore, in this study the effects of Pb concentrations (0, 50 and 100 ppm) on Vicia faba plants and attempts to alleviate this stress using chitosan (Chs; 0 and 0.1%) were performed. The results validated that with increasing Pb concentrations, a decline in growth, pigments and protein contents was observed. In the same time, a significant upsurge in the stress markers, both malondialdehyde (MDA) and H2O2, was observed under Pb stress. Nonetheless, foliar spraying with Chs improves the faba bean growth, pigment fractions, protein, carbohydrates, reduces MDA and H2O2 contents and decreases Pb concentrations under Pb stress. Pb mitigation effects by Chs are probably related with the activity of antioxidant enzymes, phenylalanine ammonia lyase (PAL) and proline. The application of Chs enhanced the activities of peroxidase, catalase and PAL by 25.77, 17.71 and 20.07%, respectively at 100 ppm Pb compared to their control. Plant genomic material exhibits significant molecular polymorphism, with an average polymorphism of 91.66% across all primers. To assess the genetic distance created among treatments, the dendrogram was constructed and the results of the similarity index ranged from 0.75 to 0.95, indicating genetic divergence. Our research offers a thorough comprehension of the role of Chs in lessening the oxidative stress, which will encourage the use of Chs in agricultural plant protection.

Synthesis of Chitosan Silica Membrane from Petung Bamboo (<i>Dendrocalamus asper</i>) Leaves and Its Application as Pb(II) Metallic Adsorbent

Membrane synthesis through a phase inversion method using chitosan and sodium silicate solutions has been conducted. This research aims to characterize the silica chitosan membrane (SCM) of petung bamboo leaves and determine the synthesized product's adsorption capacity for Pb(II) ions. The XRF characterization showed the silica content of petung bamboo leaves with a percentage of 78.03%. SEM analysis before adsorption is around 13.0 μm, and the pore diameter after adsorption is around 9.7 μm. The results of adsorption analysis of Pb(II) metal using AAS showed that the SCM variation A at an initial concentration of 10.0000 ppm Pb(II) metal adsorbed was 9.8101 ppm, and at an initial concentration of 25.0000 ppm Pb(II) metal was 22.3421 ppm. The variation B at an initial concentration of 10.0000 ppm Pb(II) metal adsorbed was 9.8870 ppm and at an initial concentration of 25.0000 ppm Pb(II) metal adsorbed was 23.5806 ppm. The variation C at an initial concentration of 10.0000 ppm Pb(II) metal adsorbed was 9.9639 ppm, and at an initial concentration of 25.0000 ppm Pb(II) metal was 24.1855 ppm. The results of this research conclude that the highest SCM adsorption power is variation C (2%:22.95%) with a percentage of 99.63%.

Determination of Heavy Metal Contents in some Medicinal Plants from The Region of Oran from Algeria

Background: Some heavy metals found in our environment are toxic; once absorbed by plants, they build up in tissues and are phased out. Other heavy metals are trace elements needed for human health, but they can be toxic in excess concentrations. Objective: The purpose of this study is both to confirm the necessary metals' recognized medicinal virtues and to raise awareness of the presence of harmful non-essential metals that could harm humans and the environment. Methods: This study depicts a profile of existence of heavy metals (Zn, Cu, Cd, Pb, Fe) in some important herbal plants used in some parts of the country as a food condiment like (Moringa oleifera, Artemesia campestis, Nigella sativa, Asparagus stipularis, Sesamum indicum, Ruta montana, Rhamnus alaternus, Pistacia lentiscus using atomic absorption spectrophotometer. Results: The heavy metals in these medicinal plants were in the range of 0.38-0.56ppm of Zn, 0.00- 0.69 ppm of Cu, 0.13-0.16 ppm of Cd, 0.26-0.52 ppm of Pb, 1.10-8.89 ppm of Fe. Of the eight medicinal plants/products examined, the prescribed limits were respected. For each plant, a test sample of 2 grams of powder is mineralized. Each mineral is analyzed by injection. For each element, a calibration curve is generated. Assay with atomic absorption devices (lead, copper, cadmium, nickel, manganese) is carried out. The results are expressed in mg/L for different species. The highest value is lead. Copper content is present in various extracts and is considered a good source. Conclusion: The obtained results are promising for human health. The zinc contained in Moringa is very valuable. The presence of iron in the species Rhamnus alaternus confirms its use in traditional medicine as an anti-anemic.

Insight into the mechanisms of efficient selective removal of Pb2+ from wastewater by nano-flowered MoS2/NHCS electrodes

The shortage of clean water resources has become a major challenge to global sustainable development, and lead (Pb) pollution in natural water has made the issue even more severe. Efficiently removal of Pb2+ is a severe challenge to Lead-containing sewage disposal. Here, efficiently selective removal of Pb2+ from wastewater was tested over hollow nano-flowered MoS2/N-doped hollow carbon spheres (MoS2/NHCS) cathodes by capacitive deionization (CDI) process. The MoS2/NHCS electrodes exhibited an excellent removal efficiency of 96.9 % in 20 ppm Pb(NO3)2 solution at U = 1.2 V, pH = 6, and 40 mL/min of flow rate. In addition, MoS2/NHCS electrodes showed excellent regeneration ability in 10 ppm Pb2+ solution and still could reach 97.7 % after 20 cycles, especially the good selective removal efficiency in the mixed solution. In situ Raman spectrum and DFT calculations indicate that efficient selective removal of Pb2+ was attributed to Pb2+ directly combined with partially negatively charged S2- to generate PbS, and some S ions transformed into S2-2 by received electrons, which further combines with Pb2+ to form PbS2. Hence, this work proposes an innovative adsorption mechanism for selective capacitive removal of Pb2+ and provides the potential practical application for treating Lead-containing wastewater.

Lead-based paint detection using perovskite fluorescence and X-ray fluorescence

BackgroundIngestion of flakes of Pb-based paint by infants remains a global health hazard with life-long consequences. Pb-based paint was banned for residential use in the US and Western Europe decades ago but is still sold in many countries. This study evaluates the performance of a new kit for detecting exposed Pb-based paint relying on the formation of Pb-halide perovskite that fluoresces bright green under a UV flashlight after spraying a non-toxic reagent. ResultsTests with the Lumetallix kit were conducted in parallel with X-fluorescence and inductively-coupled plasma atomic emission analysis upon acid digestion using paint currently sold in Côte d'Ivoire and samples of older US paint. Comparison of the three different methods indicates a detection limit for the Lumetallix kit of approximately 500 mg kg−1 (ppm) Pb in paint, with a sensitivity of 95 % and selectivity of 94 % relative to that threshold (n = 76). This detection limit is an order of magnitude below the US definition of Pb-based paint of 0.5 % (5,000 ppm) Pb by weight. SignificanceBecause the kit is easy to use, exposed paint posing a risk could reliably be screened at scale by the general public. Any follow-up for confirmation and mitigation based on XRF measurements will need to consider that Pb-based paint covered with low-Pb paint will not respond to the kit but will be detected by XRF through the overpainted layer.

Copper Oxide Anchored Carbon Nanofibers: A Versatile Platform for Multiplex Detection of Antibiotics, Heavy Metals and Pesticides.

Electrochemical sensors offer promising prospects for real-time pollutant monitoring. In this study, copper oxide-dispersed graphitic carbon nanofibers (CuO-CNFs) grown via chemical vapour deposition were employed as a robust platform for detecting a variety of environmental pollutants. This array-based sensor adeptly identifies three different classes of analytes, i. e., antibiotics (chloramphenicol (CP) and tylosin tartrate (TT)), heavy metals (cadmium (Cd) and lead (Pb)), and pesticides (quinalphos (QP) and imidacloprid (IP)). Electron collection is facilitated by a glassy carbon electrode, while various physico-electrochemical methods delve into the properties of CuO-CNFs. The CuO-CNF-modified GCE array rapidly discerns (<15 sec) a broad linear range: 1-20 ppm for CP, 1-13.33 ppm for TT, 0.66-11.66 ppm for Cd, 20-33.33 ppm for Pb, 1.6-11.6 ppm for QP, and 5-25 ppm for IP, boasting quantification limits of 1.0, 1.0, 0.66, 20.0, 1.6, and 5.0 ppm for CP, TT, Cd, Pb, QP, and IP, respectively. Notably, this sensor achieves simultaneous identification of mixed analytes, including CP and TT, Cd and Pb, and QP and IP, within real tap water. Furthermore, the electrochemical sensor exhibits robustness; heightened sensitivity, selectivity, and stability; a swift response; and impressive reproducibility in detecting CP, TT, Cd, Pb, QP, and IP within aqueous samples. Consequently, this array-based electrochemical sensor has emerged as a rapid and simultaneous detection tool for diverse pollutant residues in surface and groundwater samples.

Mitigation of lead toxicity in Brassica juncea L. by sulphur application – Via various biochemical and transcriptomic strategies

The present study was designed to elucidate whether exogenously applied sulphur (S) (S1; 100 ppm, S2; 200 ppm S) alleviate lead (Pb)-induced (Pb1; 100 ppm, Pb2; 200 ppm and Pb3; 300 ppm Pb) stress in the leaves of Brassica juncea. To study this effect, oxidative stress biomarkers (hydrogen peroxide and malondialdehyde), enzymatic antioxidants (ascorbate peroxidase (APX), glutathione reductase (GR)), non-enzymatic antioxidants (chlorophyll and carotenoids) and S-metabolic enzymes like adenosine triphosphate sulfurylase (ATPS), O-acetylserine(thiol)lyase (OASTL) were studied. Pb treatment dramatically inhibited plant development by increasing lipid peroxidation and hydrogen peroxide (H2O2) accumulation by 34.82 and 238.89 % respectively at 90 days plant. The overproduced oxidative biomarkers alter plant cell homeostasis. In contrast, APX (25.56 %) and GR (32.45 %) activities, chlorophyll (15.51 %) and carotenoids (30 %) contents increased under similar Pb treatments and regulated ROS-antioxidant balance. Exogenous S application, maintained the redox status of cell by further increasing the enzymatic activities. Pbtreatment increased S assimilation in Brassicaby elevating enzyme activities of ATPS andOASTL, which was further augmented by S supplementation toPb-stressed plants. Besides gene expression of BjSULT, BjOASTL and BjGR1 exhibited slight increase under Pb stress, S application to the stressed plants doubled the expression and assisted the stress resistance. Overall, our findings demonstrate that S protect Pb-stressed Brassica seedlings, implying that S could be an ideal choicefor reducing Pb toxicity in crops.

Tracing Detrital Epidote Derived from Alteration Halos to Porphyry Cu Deposits in Glaciated Terrains: The Search for Covered Mineralization

Abstract Distal alteration related to porphyry Cu mineralization is typically characterized by an abundance of green minerals, such as epidote, tremolite, and chlorite, within the propylitic and sodic-calcic alteration zones and extends far outside (&amp;gt;1 km) the mineralized zone(s). Glacial erosion and dispersal derived from rocks affected by propylitic and sodic-calcic alteration have resulted in the development of extensive dispersal trains of epidote in till (glacial sediment) that can reach 8 to 330 km2 as observed at four porphyry Cu study sites in the Quesnel terrane of south-central British Columbia: Highland Valley Copper, Gibraltar, Mount Polley, and Woodjam deposits. At each of these sites, epidote is more abundant in heavy mineral concentrates of till collected directly over and down-ice from mineralization and associated alteration. Epidote grains in till with &amp;gt;0.6 ppm Sb and &amp;gt;8 ppm As (as determined by laser ablation-inductively coupled plasma-mass spectrometry) are attributed to a porphyry alteration provenance. There is a greater abundance of epidote grains with high concentrations of trace elements (&amp;gt;12 ppm Cu, &amp;gt;2,700 ppm Mn, &amp;gt;7 ppm Zn, and &amp;gt;37 ppm Pb) in each porphyry district compared to background regions. This trace element signature recorded in till epidote grains is heterogeneously distributed in these districts and is interpreted to reflect varying degrees of metal enrichment from a porphyry fluid source. Tracing the source of the epidote in the till (i.e., geochemically tying it to porphyry-related propylitic and/or sodic-calcic alteration), coupled with porphyry vectoring tools in bedrock, will aid in the detection of concealed porphyry Cu mineralization in glaciated terrains.

Spatial distribution of paddy field’s heavy metals diversity contamination in Samarinda using remote sensing imagery

Abstract. Palupi NP, Hardi EH, Fahrunsyah, Rahayu DE, Nugroho RA, Darma S, Idris SD. 2023. Spatial distribution of paddy field’s heavy metals diversity contamination in Samarinda using remote sensing imagery. Biodiversitas 24: 6743-6752. The adverse effects of heavy metal contamination on rice fields posing a significant threat to food safety. This study, conducted from May to July 2023 in Samarinda East Kalimantan, Indonesia, aims to determine the distribution of active rice fields and heavy metal contamination through Kriging's interpolation method. Aerial photographic interpretations, facilitated by ArcGIS 10.4, were performed with 144 sample points within 4 Districts. The content of heavy metals was assessed by Atomic Absorption Spectroscopy at specific wavelengths: 248.3 nm for Fe, 228.8 nm for Pb, 283.3 nm for Cd, 357.9 nm for Cr, 279.5 nm for Mn, 213.9 nm for Zn, and 324.7 nm for Cu, following guidelines of SNI 8910:2021. The research showed that existing rice fields were concentrated in North Samarinda District (380,416 ha), Loa Janan Ilir District (210,133 ha), Sambutan District (404,682 ha), and Palaran District (188,617 ha) with Fe content ranged from 4.976,45 ppm to 16.800,485 ppm, exceeding the critical Fe limit in soil of 500 ppm set by SNI. Mn content ranged from 22.65 ppm to 564.88 ppm, surpassing the critical soil threshold of 0.15 ppm for Mn according to SNI. Cu content varied from 3.32 ppm to 121.75 ppm, exceeding critical Cu limit of 0.04 ppm. Zn content ranged from 8.61 ppm to 223.12 ppm, surpassing the critical limit of Zn's pollution in the soil (0.06 ppm). Pb content ranged from 10.72 ppm to 32,84 ppm, categorized as intermediate compared to the threshold of 0.07 ppm for Pb in soil. Cd content ranged from 0.04 ppm to 0.739 ppm, exceeding the critical limit of 0.01 ppm set by SNI. Cr content was detected to be less than 0.032 ppm, falling into a very low category, with the critical limit for Cr content in soil set at 0.5 ppm according to SNI.

Pb (II) Adsorption over Activated Carbon Prepared from Cedrus Deodara Bark by Na2CO3 Activation: Optimal Design for Modelling and Process Optimization

AbstractCedrus deodara is an evergreen cone‐bearing tree and its bark is a common timber industry waste. Activated carbon (CDAC) was prepared from Cedrus deodara bark through Na2CO3 – activation for efficient adsorption of Pb (II) ions. D‐optimal design based on RSM revealed that optimum conditions for preparation of activated carbon involved impregnation ratio=1.02 : 1 (w/w) and pyrolysis temperature=604.7 °C. Using 0.1 g CDAC in 200 ml of 10 ppm Pb (II) solution provided 99.4 % removal at pH 6. D‐optimal design was also employed to optimize the adsorption process and to examine influence of operational parameters including pH, initial Pb (II) concentration and contact time. CDAC was characterized using FE‐SEM, EDS, FTIR, XRD and BET analysis. Adsorption followed pseudo‐second‐order kinetic model and Langmuir isotherm model with maximum monolayer adsorption capacity 236.41 mg g−1. The free energy change (▵G̊=−12.66 kJ mol−1), entropy change (▵S̊=0.28 kJ K−1 mol−1), and enthalpy change (▵H̊=72.07 kJ mol−1) revealed spontaneous and endothermic characteristics of adsorption. For evaluating the performance of CDAC, river water samples from Sangam, a pilgrimage site of India, were treated using a vertical column packed with CDAC. Additionally, the effective cost of CDAC was also evaluated.

Genesis of sediment‐hosted copper and silver mineralization at the Omatapati prospect, Kaoko Belt, Opuwo district, Kunene region, Namibia

AbstractThe Omatapati copper and silver prospect within the Kaoko Belt is located in the Opuwo district, Kunene region, Namibia. The prospect is hosted by dolomite and interbedded argillites of the Neoproterozoic Devede Formation, the Ombombo Subgroup. An ore body is exposed in shallow artisanal mining pits and drill‐cores of the prospect have grades of 0.4 to 5.2 wt% Cu, and 23 to 312 g/t Ag. The prospect was formed by both hypogene and supergene mineralization processes. The hypogene mineralization occurred in three stages. Stage 1 is represented by calcite veins containing chalcopyrite, bornite, sphalerite and galena. Stage 2 consists of quartz and calcite veins with chalcopyrite and bornite. Stage 3 consists of quartz‐calcite‐barite veins with chalcopyrite. The veins of stages 1 and 2 are subparallel or discordant to the foliation of argillites, and those of Stage 3 are NE‐striking and steeply dipping in the brecciated dolostone and argillite. The mineralization stages 1, 2, and 3 are overprinted by supergene chalcocite, digenite, annite, covellite, malachite, delafossite, hematite, and goethite. The supergene process forms a semi‐massive chalcocite‐covellite zone, which extends from the surface to ~50 m depth. The veins show average concentrations of 2.1 wt% Cu, 80 ppm Ag, and 532 ppm Pb for the stage 1, 3.1 wt% Cu, 118 ppm Ag, and 66 ppm Pb for the stage 2, and 18.6 wt% Cu, 675 ppm Ag, and 565 ppm Pb for the Stage 3 with supergene overprinting. Silver occurs as impurity in supergene chalcocite (6303 ppm Ag), digenite (4425 ppm Ag), and covellite (3060 ppm Ag). Fluid inclusions in quartz and calcite revealed that the hypogene mineralization occurred under a pressure &gt;7–8 MPa. Temperatures of ore formation of the stages 1, 2, and 3 were &gt;145–155 °C, &gt;290–300 °C, and &gt;190–230 °C, respectively. Large variation of salinities in each fluid inclusion assemblage suggests fluid mixing and dilution processes. Fluid inclusion gas compositions in the Stage 3 have weighted means of 98.98 mol% H2O, 0.75 mol% N2, 0.52 mol% CO2, 0.02 mol% CH4, 0.0021 mol% Ar, 0.0009 mol% H2S, and 0.00006 mol% He and indicate a signature of magmatic fluids mixed with meteoric waters or seawater. δ34SCDT values of sulfides in the stages 1, 2, and 3 in the prospect have three data clusters, (1) near 0 ‰ of chalcopyrite in the stages 1 and 2, (2) near −11 ‰ of bornite in the stage 2, and (3) +5 to +11 ‰ of the supergene chalcocite and covellite. Modes of occurrence of ores, fluid inclusions and sulfur isotope data show that the prospect is likely the same type as sediment‐hosted copper‐silver deposits with veining found in the Central African Copperbelt.