Search Results (176)

Wheat (Triticum aestivum L.) is a strategic food crop for arid, hot regions such as the Arabian Peninsula, the Middle East, and North Africa. In these areas, production is limited by extreme environmental and agronomic conditions, leading to heavy dependence on imported wheat. Irrigation is often essential for successful cultivation, but available water sources are frequently saline. This study evaluated the comparative effects of irrigation salinity and genotype on agronomic performance, physiological responses, and grain quality. Nine Syrian wheat genotypes and one French bread-making cultivar, Florence Aurora, were grown in sandy soil under three irrigation salinity levels (2.6, 10, and 15 dS m⁻¹) across two seasons at the International Center for Biosaline Agriculture (Dubai, UAE). Salinity strongly negatively impacted yield, which decreased by 61% from the control to 15 dS m⁻¹, along with key yield components such as thousand grain weight and total biomass. Physiological traits, including carbon isotope composition (δ¹³C) and Na concentrations in roots, shoots and grains, increased significantly with salinity, while chlorophyll content showed a modest decline. Effects on grain quality were relatively minor: total nitrogen concentration and most mineral levels increased slightly, mainly due to a passive concentration effect associated with reduced TGW. Genotypes varied significantly in yield, biomass, TGW, physiological traits, and grain quality. The highest-yielding genotypes under control conditions (ACSAD 981 and ACSAD 1147) also performed best under saline conditions, and no trade-off was observed between yield and grain quality parameters (TGW, nitrogen, zinc, and iron concentrations). Separate analyses conducted for control and saline treatments identified different drivers of genotypic variability. Under control conditions, chlorophyll content, closely linked with δ¹³C, was the best predictor of genotypic differences and was positively correlated with yield across genotypes. Under salinity stress, grain magnesium (Mg) concentration was the strongest predictor, followed by grain δ¹³C, with both traits positively correlated with yield. These findings highlight key physiological traits linked to salinity tolerance and offer insights into the mechanisms underlying genotypic variability under both optimal and saline irrigation conditions. Full article

Background/Objectives: There are substantial beneficial health effects from a diet rich in whole grains. However, a high intake of whole grain, and hence a high intake of the iron absorption inhibitor phytate, may result in the impaired bioavailability of non-heme iron. The study examined non-heme iron absorption in healthy women from two portions (80 g and 120 g) of identical whole grain bread, baked with or without phytate-degrading techniques. Methods: The study included two single-blinded iron isotope trials. Subjects were served meals containing whole grain rye bread, which was either baked from scalded flour or sourdough-fermented flour labeled with ⁵⁵Fe or ⁵⁹Fe. The absorption of non-heme iron from the meals was measured through the erythrocyte incorporation of radioiron isotopes. Results: Iron absorption from the 80 g high-phytate bread was 7.0 ± 4.1% (mean ± SD, n = 8). Iron absorption from the 80 g dephytinized bread was 19.1 ± 15.1% (mean ± SD) and thus on average 2.8 times higher compared to the absorption from the high-phytate bread (p = 0.001). Iron absorption from the 120 g high-phytate bread was 4.6 ± 2.9% (mean ± SD, n = 17). Iron absorption from the 120 g dephytinized bread was 15.0 ± 9.2% (mean ± SD) and thus on average 3.5 times higher compared to the absorption from the high-phytate bread (p = 0.001). Conclusions: Iron uptake was significantly higher from dephytinized bread compared to scalded bread. And the higher the amount of phytate, the higher the beneficial effects on iron absorption from dephytinization. Full article

In the early Paleoproterozoic, the Earth’s atmosphere–ocean system shifted from a reducing to an oxidizing state, triggering the extensive deposition of banded iron formations (BIFs) in the Siderian period (2.5–2.3 Ga). As a key sedimentary formed during the hydrospheric oxidation stage, BIFs are expected to preserve abundant microbial fossils or organic carbon. However, evidence for contemporaneous widespread biological activity remains limited. This paper focuses on C-O isotopes and the trace element geochemistry of the 2.5 Ga Jining BIF to constrain the redox state of paleo-oceans and associated biogeochemical cycling during BIF deposition. The δ¹³C_carb values of the BIF samples range from −18.6‰ to −9.6‰, with an average of −12.7‰, exhibiting a notable negative value, and TOC contents (0.04–0.19 wt.%) are extremely low. This suggests the incorporation of oxidized organic carbon to pore water via ferrihydrite reduction during early diagenesis process. The globally negative δ¹³C_carb value of BIFs and iron-rich carbonates reflect enhanced biological activity at ~2.5 Ga. REE patterns reveal negative Ce/Ce*_(SN) and Eu/Eu*_(CN) anomalies, and the presence of primary hematite mesobands together indicate that the Jining BIF records a redox transition in seawater from reducing to oxidizing conditions. Full article

Background: Radioactive colloids are considered the standard of care for sentinel lymph node (SLN) detection. An alternative detection method using superparamagnetic iron oxide (SPIO) nanoparticles is well documented in breast cancer but poorly studied for gynecological tumors, including vulvar cancer (VC). Objective: Our aim was to evaluate the feasibility, accuracy, and safety of SPIO nanoparticles for SLN mapping in patients with VC as a stand-alone technique compared with the combination of two methods: the standard of care using a radioactive isotope (technetium-99; Tc-99) and SPIO as a new tracer. Methods: We conducted a prospective and observational study of SLN mapping in patients with stage IB VC and tumor size ≤ 4 cm. We calculated detection and malignancy rates per patient and per groin in both study groups. During the 36-month follow-up, the groin recurrence rate was estimated for positive and negative SLNs. Kaplan–Meyer curves were used to analyze the probability of survival, depending on disease-free survival. Results: A total of 110 groins assessed by SLN in 60 patients included in this study were analyzed (70 groins from 40 patients in the group with a single tracer and 40 groins from 20 patients in the group of combined tracers). At least one sentinel lymph node was detected in every patient while the bilateral detection rate was 92.3% for the SPIO group and 88.2% for the Tc-99 and SPIO group. The groin detection rate was 94.3% and 90%, respectively. SLN mapping failure was similar in both groups (2.8% and 2.5%, respectively). During a 3-year follow-up, the isolated groin recurrence rate was 2.1% for negative groins and for disease-free survival it was 28.9 months in the combined tracer group versus 32.8 months in the SPIO group. The Kaplan–Meyer curves showed the increased probability of survival for the SPIO group (87.5%); however, it was insignificant. Conclusions: SLN mapping using the SPIO technique in patients with VC is non-inferior to the combined SPIO and Tc-99 method. Full article

Thorium-rare earth-iron oxide deposits of the Lemhi Pass district, Idaho and Montana, are enriched in the middle rare earth elements (REE), and particularly neodymium (Nd). Overall, thorium (Th) and total rare earth oxide (TREO) grades of the deposits are sub equal at 0.4 wt. % but locally exceed 1 wt. % TREO. Nd-monazite, the major REE phase (35 wt. % Nd₂O₃) occurs in hydrothermal Th-REE mineralized quartz veins and biotite-rich shear zones of enigmatic origin. Hosted in Mesoproterozoic metasedimentary rocks, the deposits are modest in size but present over a large area with no obvious source pluton exposed. This paper documents the geochemistry of the monazite and provides the first geochronological data to constrain its origin. Elemental mapping and U-Th-total Pb EPMA dating of the monazite and thorite document a Paleozoic age for mineralization centered in the Late Devonian at approximately 355 Ma ± 20 Ma. A second period of volumetrically minor Th and REE remobilization is dated as Mesozoic (ca. 100 Ma). For context, a reactivated passive continental margin was present during the Devonian in eastern Idaho, while the Mesozoic was a time of major accretionary tectonics and arc magmatism further west. Nd and Pb isotopic data require a significant interaction of the fluids with an ancient crustal component represented by regional Mesoproterozoic metasedimentary rocks and granitoids. A source–transport–deposition model is hypothesized with metasomatic fractionation and enrichment of Nd during regional hydrothermal circulation. The aqueous fluids were hot, oxidizing, and likely saline, but the exact source of the Th and REEs and the mechanism of enrichment remains problematic. Additional analytical work and increased knowledge of the regional and district geology will improve this unconventional hypothesis for formation of Lemhi Pass’ unusual Nd-rich Th-REE-Fe mineralization. Full article

The Puebla Metropolitan Area, one of the most industrialized regions in Mexico, shows severe contamination of both surface and groundwater. In this study a multi-tracer approach combining hydrochemistry with environmental isotopes (δ²H, δ¹⁸O, ³H) was applied to evaluate groundwater–surface water (GW–SW) interactions and their role in water quality degradation. Elevated concentrations of aluminum, iron, zinc, and lead were detected in the Alseseca and Atoyac Rivers, exceeding national standards, while arsenic, manganese, and lead in groundwater surpassed Mexican and WHO drinking water limits. The main sources of contamination include volcanic inputs from Popocatepetl activity (e.g., arsenic) and untreated discharges from industrial parks (e.g., lead), which together introduce significant loads of Potentially Toxic Elements (PTEs) into surface and groundwater. Isotopic analysis identified three sources for aquifer recharge: (1) recharge from high-altitude meteoric water, (2) mixed GW–SW water recharged at intermediate elevations with heavy metal presence, and (3) recharge from lower altitudes (evaporate water). Tritium confirmed both modern and old recharge, while isotope-based mixing models indicated surface water contributions to groundwater ranging from 18% to 72%. These interpretations were derived from the integrated analysis of hydrochemical and isotopic data, allowing the quantification of recharge sources, residence times, and mixing processes. The results demonstrate that hydraulic connectivity, enhanced by fractures and faults, facilitates contaminant transfer from polluted rivers into the aquifer. Full article

The Kavokta deposit in Russia contains gray and black dolomite-type nephrite, which is in high demand commercially. Although the fact that black nephrite has been found in several deposits, the reasons for its color are not well understood. The present study aims to identify the localization and mineral composition of gray and black nephrite, and to determine the reasons for its dark coloration. The mineral composition of nephrite was studied using a scanning electron microscope with energy-dispersive microanalysis (SEM-EDX) and X-ray phase analysis. Also, the isotopic composition of carbon in graphite in nephrite and in carbonates associated with nephrite in the surrounding strata was determined. The gray–black color in most samples from the southeastern part of the Kavokta deposit (lodes 17 and 28 of the nephrite-bearing zone 4 of the Medvezhy section and lode 6-1 of the nephrite-bearing zone 6 of the Levoberezhny section) is due to the presence of graphite. Syngenetic graphite formed both by the organic matter buried in dolomites and by the decomposition of carbon dioxide that is released during decarbonation under the influence of deep-seated hydrogen. The color of nephrite also depends on the iron content, changing from white to light green as the iron content increases. The gray color of tremolite–diopside nephrite is due to the development of chlorite aggregates that replace diopside and/or tremolite. The gray-green to black color of the nephrite in the northwestern part of the Kavokta deposit (lode 1 of the nephrite-bearing zone 1 of the Prozrachny section) is due to the high iron content in the tremolite–actinolite at the contact with the epidote–tremolite skarn formed after amphibolite. The identified patterns of black nephrite localization can be used in the process of geological exploration of similar deposits elsewhere in Russia and abroad. Full article

Skarn-type iron ore is economically significant, and numerous skarn ore deposits have been identified in the North China Craton. The newly discovered orbicular diorite in this region is distinguished from other analogous rocks due to the accumulation of large magnetite particles, which may shed new light on the genesis of this ore type. The magnetite in different parts of the orbicular structure exhibits distinct compositional differences. For example, magnetite at the edge has a small particle size (200 μm) and is associated with the minerals plagioclase and hornblende, indicating that it crystallized from normal diorite magma. By contrast, magnetite in the core has a relatively large particle size (>1000 μm), is associated with apatite and actinolite, and contains apatite inclusions as well as numerous pores. The size of magnetite in the mantle falls between that of the edge and the core. The syngenetic minerals of magnetite in the mantle include epidote and plagioclase. The magnetites in the cores of orbicules have a higher content of Ti, Al, Ni, Cr, Sc, Zn, Co, Ga, and Nb than those in the rim. The δ⁵⁶Fe value of the core magnetite (0.46‰–0.78‰) is much higher than that of the mantle and rim magnetite in orbicules. Moreover, the δ⁵⁶Fe value of magnetite increases as the V content of magnetite gradually decreases. This large iron isotope fractionation is likely driven by liquid immiscibility that forms iron-rich melts under high oxygen fugacity. The reaction between magma and carbonate xenoliths (Ca, Mg)CO₃ during magma migration generates abundant CO₂, which significantly increases the oxygen fugacity of the magmatic system. Under the action of CO₂ and other volatile components, liquid immiscibility occurs in the magma chamber, and Fe-rich oxide melts are formed by the melting of carbonate xenoliths. Iron oxides (Fe₃O₄/Fe₂O₃₎ will crystallize close to the liquidus due to high oxygen fugacity. These characteristics of magnetite in the Tanling orbicular diorite (Wuan, China) indicate that diorite magma reacts with carbonate xenoliths to form “Fe-rich melts”, and skarn iron deposits are probably formed by the reaction of intermediate-basic magma with carbonate rocks that generate such “Fe-rich melts”. A possible reaction is as follows: diorite magma + carbonate → (magnetite-actinolite-apatite) + garnet + epidote + feldspar + hornblende + CO₂↑. Full article

The Hugushan banded iron formation (BIF) is one of the most representative iron ore deposits in the central part of the North China Craton, and its ore formation mechanism remains highly controversial. This study presents whole-rock and Fe–Si–O isotope geochemical evidence, offering a new perspective on the ore formation mechanism of the Hugushan BIFs. The samples from the upper and lower parts of the Hugushan BIFs are characterized by slight enrichment of heavy and light Fe isotopes, respectively. Additionally, the samples from the upper part of the Hugushan BIFs show characteristics of slightly positive Ce anomalies and negative La anomalies, suggesting that the shallow ancient seawater was in a partially oxidized state, whereas the deep seawater remained in a reductive environment during the depositional period. The low Al₂O₃ and TiO₂ concentrations, as well as the depletion of Zr and Hf in the Hugushan BIFs, suggest that the contribution of terrestrial detrital materials to deposition is extremely limited. The BIFs all exhibit positive Eu anomalies, and the quartz in the BIFs is depleted in ³⁰Si, a characteristic similar to that observed in siliceous rocks formed in hydrothermal vent environments and during hydrothermal plume activity. Additionally, the δ¹⁸O values of quartz in Hugushan BIFs are similar to the O isotope compositions of hydrothermal sedimentary siliceous rocks, further suggesting that the silicon in BIFs originates primarily from seafloor hydrothermal activity. The combination of Eu/Sm, Sm/Yb, and Y/Ho ratios indicates that the major components (iron and silica) of the Hugushan Iron Ore Deposit originated from the mixing of high-temperature hydrothermal fluids with seawater, with the hydrothermal fluid contributing slightly less than 0.1%. The magnetite and quartz bands in the BIFs exhibit inhomogeneous and covariant δ⁵⁶Fe and δ³⁰Si isotope characteristics, suggesting that the alternating siliceous and ferruginous layers are products of original chemical deposition in the ocean. Periodic hydrothermal activity and ocean transgression caused the recurring deposition of siliceous and ferruginous layers, resulting in the characteristic banded structure of the Hugushan Iron Ore Deposit. Full article

It is generally believed that the ancient oceans during the “boring billion” (1.85–0.8 Ga) lacked the capacity to form large-scale iron formations (IFs), though localized small-scale IFs deposition persisted. The Altyn region of China hosts abundant IFs, with the Dimunalike IFs being the largest and most representative, characterized by typical banded iron–silica layers. Detailed fieldwork identified a tuff layer conformably contacting the IFs at the roof rocks of IFs and a ferruginous mudstone layer at the floor rocks of IFs in drill core ZK4312. Geochemical and zircon U-Pb-Hf isotopic analyses were performed. The tuff has a typical tuff structure, mostly made of quartz, and contains a significant amount of natural sulfur. It also has high SiO₂ content (77.90%–80.49%) and sulfur content (0.78%–3.06%). The ferruginous mudstone has a volcanic clastic structure and is mainly composed of quartz and chlorite, with abundant coeval pyrite. It shows lower SiO₂ content (53.83%–60.32%) and higher TFe₂O₃ content (10.29%–16.24%). Both layers share similar rare earth element (REE) distribution patterns and trace element compositions, with light REE enrichment and negative Eu, Nb, and Ti anomalies, consistent with arc volcanic geochemistry. Zircon U-Pb ages indicate crystallization of the tuff at 1102 ± 13 Ma and maximum deposition of the mudstone at 1110 ± 41 Ma. These data suggest formation during different stages of the same volcanic–sedimentary process. The ε_Hf(t) values (3.60–12.35 for tuff, 2.92–8.19 for mudstone) resemble those of Algoma-type IF host rocks, implying derivation from re-melted new crust. The Dimunalike IFs likely formed in a submarine volcanic–sedimentary environment. In conclusion, although the Mesoproterozoic ocean was generally in a low-oxygen state, which was not conducive to large-scale IF deposition, localized submarine volcanic–hydrothermal activity could still lead to IF formation. Full article

Abiotic processes have ramifications in wastewater treatment, in situ degradation of organic matter, and cycling of nutrients in wetland ecosystems. Experiments were conducted to investigate abiotic oxidation of organic compounds (lactate) as a function of electron acceptors (ferric citrate and hydrous ferric oxide (HFO), media composition, and pH under anaerobic conditions, using sodium bicarbonate as the buffering agent. Dissolved inorganic carbon (DIC) was used as a proxy for the oxidation of substrates. HFO media generated more DIC compared to ferric citrate containing media. Light and pH had major roles in the oxidation of lactate in the presence of ferric iron. Under dark conditions in the presence or absence of Fe(III), the DIC produced was low in all pH conditions. Inhibition of DIC production was also observed upon photo exposure when Fe (III) was absent. Isotopically, the system showed initial mixing between the bicarbonate and the carbon dioxide produced from oxidation later being dominated by carbon isotope value of lactate used. These redox conditions align with previous studies suggesting cleavage of organic compounds by hydroxyl radicals. The slower redox processes observed here, compared to previous studies, could be due to the scavenging effect of chloride ion on the hydroxyl radical. Full article

Superior-type iron formations (IFs) represent a globally significant source of iron ore; yet, their origin remains a subject of ongoing debate. Early models proposed a continental weathering source for the iron, whereas later interpretations—mainly supported by positive europium (Eu) anomalies—favored a hydrothermal source. However, the hydrothermal model largely relies on REE systematics, and whether iron and REEs in Superior-type IFs share the same source remains uncertain. As iron isotopes directly trace the sources and fractionation history of iron, a spatial co-variation between Fe isotopes and Eu anomalies would shed new light on the iron source issue of IFs. In this study, we present new Fe isotope and REE data from the drill core WILDD004 at Wilgena Hill and integrate them with reported data for two additional drill cores: HKDD4 (Hawks Nest) and GWDD1 (Giffen Well). All three cores are stratigraphically equivalent to the Wilgena Hill Jaspilite Formation but span a lateral distance of ~100 km across the Gawler Craton, South Australia. While the Hawks Nest and Giffen Well samples exhibit both positive Eu anomalies and elevated δ⁵⁶Fe values, the Wilgena Hill samples show positive yet smaller Eu/Eu* (1.17–2.41) and negative δ⁵⁶Fe values (−0.60‰ to −1.63‰). The consistent presence of Eu anomalies and the systematic spatial correlation between δ⁵⁶Fe and Eu/Eu* across all three locations provide direct, Fe-based geochemical evidence for a hydrothermal source of iron in this Superior-type IF. Full article

The Qieliekeqi siderite deposit, located in the Tashkurgan block of western Kunlun, is a carbonate-hosted iron deposit with hydrothermal sedimentary features. This study integrates whole-rock geochemistry, stable isotopes, and zircon U–Pb–Hf data to investigate its metallogenic evolution. Coarse-grained siderite samples, formed in deeper water, exhibit average Al₂O₃/TiO₂ ratios of 29.14, δEu of 2.69, and δCe of 0.83, indicating hydrothermal fluid dominance with limited seawater mixing. Banded samples from shallower settings show an average Al₂O₃/TiO₂ of 17.07, δEu of 3.18, and δCe of 0.94, suggesting stronger seawater interaction under oxidizing conditions. Both types are enriched in Mn, Co, and Ba, with low Ti and Al contents. Stable isotope results (δ¹³C_PDB = −6.0‰ to −4.6‰; δ¹⁸O_SMOW = 16.0‰ to 16.9‰) point to seawater-dominated fluids with minor magmatic and meteoric contributions, formed under open-system conditions at avg. temperatures of 53 to 58 °C. Zircon U–Pb dating yields an age of 211.01 ± 0.82 Ma, with an average εHf(t) of −3.94, indicating derivation from the partially melted ancient crust. These results support a two-stage model involving Late Cambrian hydrothermal sedimentation and Late Triassic magmatic overprinting. Full article

The Huoqiu Group is located in the southern margin of the North China Craton and is considered an Archean geologic body. Its supracrustal rocks are divided into the Huayuan, Wuji, and Zhouji formations in ascending order. The Wuji and Zhouji formations contain large BIF-type iron deposits. The BIFs show geological and geochemical features of Paleoproterozoic Lake Superior-type rather than Archean Algoma-type. The study of the formation ages and evolutionary history of the Huoqiu Terrane will provide significant guidance for the mineralization and exploration of the Huoqiu iron deposits. In this paper, we collected all available isotopic ages and Hf isotopic compositions obtained from the Huoqiu Terrane and reassessed their accuracy and geological meanings. We conclude that the Wuji and Zhouji formations were not older than 2343 Ma. Therefore, the BIFs hosted in the Wuji and Zhouji formations must be of Paleoproterozoic age. The magmatic zircons from the TTG gneisses and granite yield U-Pb ages of Neoarchean Era, indicating that the Wuji and Zhouji formations of the Huoqiu Group were deposited on an Archean granitic basement that mainly comprises the trondhjemite-tonalite-granodiorite (TTG) gneisses and granites of the “Huayuan Formation”. The Early Precambrian crystalline basement in the Huoqiu area can be divided into the Huayuan Gneiss Complex and the Huoqiu Group, comprising the Wuji and Zhouji formations. The tectonic scenario of granitic complexes overlain by supracrustal rocks in the Huoqiu Terrane has been recognized in the Songshan, Zhongtiao, Xiaoshan, and Lushan Early Precambrian terranes in the southern margin of the North China Craton. As indicated by the zircon U-Pb ages and εHf(t) data, the crustal growth of the Huoqiu Terrane occurred mainly at ~2.9 Ga and ~2.7 Ga. Based on the sedimentary age, environment, and rhythm, the BIFs in the Huoqiu region are considered to be of Lake Superior type and of great potential for Fe ore exploration. Full article

Arsenic (As) contamination in groundwater represents a major global public health threat, particularly in alluvial aquifer systems where redox-sensitive geochemical processes facilitate the mobilization of naturally occurring trace elements. This study investigates groundwater quality, particularly focusing on the origin of arsenic contamination in shallow and deep alluvial aquifers of the Lower Sakarya River Basin, which are crucial for drinking, domestic, and agricultural uses. Groundwater samples were collected from 34 wells—7 tapping the shallow aquifer (<60 m) and 27 tapping the deep aquifer (>60 m)—during wet and dry seasons for the hydrogeochemical characterization of groundwater. Environmental isotope analysis (δ¹⁸O, δ²H, ³H) was conducted to characterize origin and groundwater residence times, and the possible hydraulic connection between shallow and deep alluvial aquifers. Mineralogical and geochemical characterization of the sediment core samples were carried out using X-ray diffraction and acid digestion analyses to identify mineralogical sources of As and other metals. Pearson correlation coefficient analyses were also applied to the results of the chemical analyses to determine the origin of metal enrichments observed in the groundwater, as well as related geochemical processes. The results reveal that 33–41% of deep groundwater samples contain arsenic concentrations exceeding the WHO and Turkish drinking water standard of 10 µg/L, with maximum values reaching 373 µg/L. Manganese concentrations exceeded the 50 µg/L limit in up to 44% of deep aquifer samples, reaching 1230 µg/L. On the other hand, iron concentrations were consistently low, remaining below the detection limit in nearly all samples. The co-occurrence of As and Mn above their maximum contaminant levels was observed in 30–33% of the wells, exhibiting extremely low sulfate concentrations (0.2–2 mg/L), notably low dissolved oxygen concentration (1.45–3.3 mg/L) alongside high bicarbonate concentrations (450–1429 mg/L), indicating localized varying reducing conditions in the deep alluvial aquifer. The correlations between molybdenum and As (rdry = 0.46, rwet = 0.64) also indicate reducing conditions, where Mo typically mobilizes with As. Arsenic concentrations also showed significant correlations with bicarbonate (HCO₃⁻) (rdry = 0.66, rwet = 0.80), indicating that alkaline or reducing conditions are promoting arsenic mobilization from aquifer materials. All these correlations between elements indicate that coexistence of As with Mn above their MCLs in deep alluvial aquifer groundwater result from reductive dissolution of Mn/Fe(?) oxides, which are primary arsenic hosts, thereby releasing arsenic into groundwater under reducing conditions. In contrast, the shallow aquifer system—although affected by elevated nitrate, sulfate, and chloride levels from agricultural and domestic sources—exhibited consistently low arsenic concentrations below the maximum contaminant level. Seasonal redox fluctuations in the shallow zone influence manganese concentrations, but the aquifer’s more dynamic recharge regime and oxic conditions suppress widespread As mobilization. Mineralogical analysis identified that serpentinite, schist, and other ophiolitic/metamorphic detritus transported by river processes into basin sediments were identified as the main natural sources of arsenic and manganese in groundwater of deep alluvium aquifer. Full article