Deciphering the complex mechanisms of action of lead detoxification by the green microalga Chlorella vulgaris.

Recent advances in photovoltaic technologies have established lead halide perovskites as benchmark materials for optoelectronic applications, but serious concerns persist regarding the toxicity of lead, their principal constituent element. In this context, bismuth-based perovskite-inspired materials have emerged as a promising lead-free alternative, offering comparable electronic characteristics. Here, we explore the structural, electronic and transport properties of Cs3Bi2I9 and Cs3Bi2Br9, two perovskite-inspired materials with significant potential for photovoltaic and photocatalytic applications. With state-of-the-art first-principles calculations, we investigate the subtle effects of iodine/bromine (I/Br) mixing on the materials' physico-chemical properties. We predict a change in phase stabilities around 40% Br content: below 30% Br, the iodine-dominant P63/mmc phase is stable, while beyond 40% Br, the bromine-dominant P-3m1 phase becomes energetically favorable, consistent with experimental observations. The electronic bandgap increases with Br content, and effective mass calculations indicate that electrons exhibit lower effective masses and higher mobility compared to holes, with hole localization intensifying as the Br content increases. Overall, our findings underscore the critical role of halogen composition in modulating the structural, electronic, and transport properties of these materials, providing valuable insights for optimizing halide contents in perovskite-inspired systems for next-generation optoelectronic applications.

Rapid and highly selective surfactant-free lead(II) ion-imprinted nanoparticles for preconcentration with negligible memory effect.

Lead remediation in contaminated soils using magnetic biochar hydrogel beads via swelling-driven hydraulic gradients and Fe3+-mediated acidification.

The molecular design of functional organic dyes as fluorescent chemosensors represents a dynamic frontier in materials chemistry, bridging synthetic dye chemistry with practical analytical applications. This review summarizes recent progress in the molecular design and photophysical properties of fluorescent sensors for metal ion detection, with particular emphasis on lead (Pb 2+ ) ions. The first part focuses specifically on Pb 2+ -responsive sensors, considering the high toxicity of lead and the need for selective chelation strategies. The second part systematically surveys diverse fluorophore backbones, including quinoline, pyrazoloquinoline, fluorescein, rhodamine, coumarin, pyrene, and Schiff base derivatives. Special attention is given to how specific structural modifications and the strategic incorporation of chelating units influence fluorescence responses and coordination selectivity. Key analytical parameters of sensor–ion systems, such as detection limits, binding constants, and complex stoichiometry, are compared across representative fluorophore-based sensorsFinally, the underlying metal-ligand interactions and fluorescence sensing mechanisms, including photoinduced electron transfer (PET), intramolecular charge transfer (ICT), chelation-enhanced fluorescence (CHEF), chelation-enhanced quenching (CHEQ) and excited state intramolecular proton transfer (ESIPT), are discussed. The review concludes with an outlook on current challenges and future perspectives in the development of selective, sensitive, and practically applicable fluorescent sensors for Pb 2+ detection. • Comprehensive review of organic dye-based fluorescent sensors for metal ion detection, with a specific focus on highly toxic Pb 2+ ions. • Comparison of sensors with different fluorophore cores (fluorescein, rhodamine, quinoline, pyrene, coumarin, Schiff base), including their detection limits, complex stoichiometry, and binding constants. • Detailed overview of the coordination chemistry of Pb 2+ -selective sensors. • Insight into the fluorescence detection mechanism (PET, ICT, CHEF, CHEQ, ESIPT) as a key design element for improving sensor selectivity and sensitivity.

Lead is a toxic heavy metal with significant health risks, as maternal lead exposure during pregnancy disrupts fetal neural development through placental transfer, leading to persistent neurological, developmental, and long-term health consequences in the progeny. Lead exposure typically affects the central nervous system, which is especially harmful during fetal development and early infancy. This review emphasizes the impact of early developmental exposure leading to disruption of neurotransmitter mechanisms. Mechanistically, lead disrupts neurodevelopment through various pathways, including alterations in myelin proteins, synaptic function, and neuroinflammatory responses, by interfering with the regulatory action of calcium, as lead mimics and replaces calcium. Alterations caused by lead, particularly in the dopaminergic, cholinergic, glutamatergic, and GABAergic pathways, increase the risk of neurodevelopmental disorders such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and cognitive disabilities in children. Lead is known to induce cellular, molecular, and epigenetic changes that impair neuronal connectivity, synaptic plasticity, and network functionality, ultimately leading to the disruption of neurodevelopmental pathways. The cumulative evidence highlights various aspects of lead neurotoxicity and emphasizes its role in the etiology of neurodevelopmental impairments. Understanding these pathways is critical for early intervention strategies to mitigate the long-term cognitive and behavioral consequences of lead exposure during sensitive developmental periods.

Plant stress responses are shaped by both the plant genome and its associated microbial communities, which together form the plant holobiont. Given the rapid adaptive potential of plant-associated microbes, we hypothesised that directed evolution under selective pressure can accelerate the development of holobiont-level stress tolerance. Directed evolution of the plant-associated bacterium Bacillus subtilis MR21 produced three evolved strains (EV1-EV3) with distinct plant-beneficial traits. These strains enhanced coriander growth under conditions of lead (Pb) toxicity and micronutrient deficiency. The evolved bacteria improved rhizosphere conditions by reducing Pb availability and increasing the availability of essential nutrients, including phosphorus, iron and zinc, thereby enhancing plant holobiont stress tolerance. In addition, rhizosphere detoxification and elevated production of organic acids, such as succinic and glutamic acid, contributed to improved soil chemical conditions. Together, these processes promoted a by-product mutualism within the rhizosphere, in which detoxifying bacteria indirectly supported less beneficial members of the microbial community. We conclude that directed evolution of plant-associated bacteria provides a natural and efficient strategy to enhance plant stress tolerance at the holobiont level, offering a complementary approach to conventional breeding and genetic engineering.

Lead contamination of groundwater remains a serious environmental and public health concern, particularly in urban regions where borehole water serves as a major domestic water source. Conventional analytical techniques such as atomic absorption spectroscopy (AAS) and inductively coupled plasma-based methods provide excellent sensitivity for trace metal determination but are often limited by high cost, technical expertise requirements, and infrastructural constraints in many developing regions. In this study, a simple Schiff-base ligand derived from salicylaldehyde (0.01mol) and ethylenediamine (0.01mol) was synthesized under reflux for 2h and evaluated as a low-cost colorimetric sensor for Pb2+ detection in borehole water collected from Kaduna metropolis, Nigeria. The ligand was obtained as a yellow crystalline product with a percentage yield of 78.4% and melting point of 189-191°C. FT-IR analysis confirmed successful azomethine formation with ν(C=N) band at 1624cm-1, while 1H NMR spectroscopy showed characteristic azomethine proton resonance at δ 8.31ppm, aromatic proton signals at δ 6.82-7.45ppm, methylene linker protons at δ 3.76ppm, and phenolic OH resonance at δ 12.94ppm, confirming ligand formation. Coordination of Pb2+ through azomethine nitrogen and phenolic oxygen donor sites was accompanied by a shift of the ν(C=N) band to 1598cm-1 and formation of a probable distorted hemidirected Pb(II) coordination geometry, producing a visible color change from pale-yellow to orange with the emergence of an absorption band at 445nm. Good linearity was obtained over the investigated concentration range with correlation coefficient (R2 = 0.995), slope-based sensitivity of 0.126 AU mg-1 L, limit of detection (LOD) of 0.82mg/L, and limit of quantification (LOQ) of 2.49mg/L. Selectivity studies showed stronger response toward Pb2+ relative to competing ions such as Cu2+, Zn2+, Ni2+, Fe3+, and Cd2+ tested at 50mg/L under identical conditions. Application to twelve borehole water samples produced recovery values of 92-98% with relative standard deviations below 3.0%, indicating satisfactory precision and analytical applicability. Although not intended to replace ultra-trace instrumental methods, the developed sensor offers a simple, rapid, and affordable approach for preliminary groundwater lead monitoring and may serve as an early-warning screening tool for potentially contaminated water sources in resource-limited settings.

Lead (Pb) and cadmium (Cd) are pervasive toxicants that bioaccumulate and cause multisystem injury. Two controlled experiments were conducted in quails, subdivided into co‑exposure (ascorbic acid (AA) given concurrently with Pb or Cd for four weeks) and post‑exposure (AA administered for three weeks after one week of metal exposure). Birds received Pb acetate or Cd chloride (500 ppm) with AA (1000 ppm). In the Pb experiment, co‑exposure with AA significantly reduced tissue burdens compared with Pb alone: liver (16.7 ± 0.8 vs. 29.0 ± 1.3 ppb), thigh (3.2 ± 0.6 vs. 10.6 ± 1.3 ppb), brisket (2.4 ± 0.4 vs. 13.7 ± 0.5 ppb), brain (21.7 ± 3.3 vs. 36.0 ± 3.9 ppb), bone (567.2 ± 81.6 vs. 1411.2 ± 9.8 ppb), and blood (15.1 ± 1.4 vs. 36.9 ± 3.7 ppb; all p < 0.001). Post‑exposure AA also lowered concentrations: liver (3.9 ± 1.4 vs. 12.3 ± 0.3 ppb), thigh (1.9 ± 0.3 vs. 11.3 ± 1.0 ppb), brisket (1.2 ± 0.1 vs. 6.4 ± 0.5 ppb), brain (5.7 ± 0.2 vs. 25.4 ± 1.4 ppb), bone (109.9 ± 23.6 vs. 384.5 ± 35.7 ppb), and blood (9.2 ± 0.9 vs. 19.9 ± 1.7 ppb; all p < 0.001). In the Cd experiment, co‑exposure with AA reduced tissue levels: liver (4381.5 ± 281.2 vs. 9291.1 ± 278.3 ppb), thigh (47.2 ± 1.0 vs. 116.6 ± 1.7 ppb), brisket (50.6 ± 3.6 vs. 82.8 ± 2.3 ppb), brain (31.4 ± 1.1 vs. 66.1 ± 2.7 ppb), bone (416.7 ± 11.0 vs. 562.3 ± 10.9 ppb), and blood (174.1 ± 7.9 vs. 298.5 ± 6.6 ppb; all p < 0.001). Post‑exposure AA likewise lowered burdens: liver (1109.5 ± 156.8 vs. 3200.6 ± 324.4 ppb), thigh (5.3 ± 0.5 vs. 32.6 ± 4.1 ppb), brisket (3.8 ± 0.7 vs. 30.4 ± 2.3 ppb), brain (6.5 ± 0.9 vs. 44.5 ± 5.8 ppb), bone (43.5 ± 3.1 vs. 187.6 ± 14.6 ppb), and blood (63.3 ± 1.1 vs. 143.5 ± 15.4 ppb; all p < 0.001). Across both paradigms, co‑exposure with AA generally produced larger relative reductions in tissue burdens compared with post‑exposure treatment, although both approaches were effective. Given its safety, availability, and low cost, AA may be incorporated into strategies for populations at risk of heavy metal exposure.

Drought and heavy metal (HM) contamination severely constrain maize productivity in dryland agriculture. While ascorbic acid (AA) and salicylic acid (SA) are recognized as protective agents against abiotic stress, their comparative efficacy and synergistic potential under combined stress remain poorly understood. This study evaluated individual and combined applications of AA (100 mg·L-1, equivalent to 0.57 mM) and SA (0.5 mM) on maize ('Zhengdan No. 16') subjected to four water regimes: well-watered (WW 100%), mild water stress (MWS 75%), moderate water stress (MoWS, 50%), and severe water stress (SWS, 30% field capacity), with or without Pb (200 μM) or Cd (100 μM) exposure. Photosynthetic pigments, gas exchange, phytohormones (ABA, IAA), oxidative stress markers (H2O2, SOD), and macronutrient uptake (N, P, K) were quantified. The Pb concentration (200 μM) was selected based on preliminary dose-response experiments (0, 100, 200, 400 μM), where 200 μM caused significant but non-lethal growth inhibition (30%-40% biomass reduction), allowing assessment of AA/SA mitigation without complete growth arrest. Under WW conditions, AA increased chlorophyll a by 11.0% and SA by 14.5% versus controls. Combined AA+SA + Cd improved selected nutrient responses, including a 2.8% increase in leaf N and a 4.5% increase in leaf K relative to Cd alone under WW conditions; however, leaf P did not increase under all water regimes. AA reduced Cd-triggered H2O2 by approximately 30% and Pb-triggered H2O2 by approximately 18% (P < 0.05). Under SWS, combined treatments improved selected photoprotective responses, including a 14.3% increase in carotenoid content, although Chl a responses were treatment and metal-specific. Exogenous AA and SA, particularly in combination, enhance dryland maize resilience to combined drought and HM stress through improved photosynthesis, reduced oxidative damage, and optimized nutrient acquisition. These findings support antioxidant biostimulants as sustainable tools for crop stress.

Heavy metals are widely recognized as potent teratogenic agents capable of inducing congenital malformations by disrupting normal embryonic development. The present study investigated the teratogenic potential of lead (Pb) and copper (Cu) on chick embryos using two exposure methods: immersion and in Ovo injection. A total of 100 fertile eggs were randomly allocated into five experimental groups: control (CT), lead immersion (Pb-IM), lead injection (Pb-INJ), copper immersion (Cu-IM), and copper injection (Cu-INJ). Eggs were incubated under conventional conditions and treatments were given on the first day. On day 19, embryos were examined for morphological, morphometric, and histological alterations. Control embryos developed normally whereas treated groups exhibited significant abnormalities including reduced body weight, decreased crown rump length, shortened biparietal distance and craniofacial and limb deformities. Multivariate analysis revealed a highly significant overall effect of treatment on developmental parameters (Pillai's Trace = 0.988, p < 0.001). Subsequent univariate ANOVA showed significant differences (p < 0.05) across all measured variables. Post hoc comparisons confirmed that lead injected embryos exhibited the most severe reductions. Histological examination revealed normal hepatic and cardiac architecture in the control group. In contrast, treated embryos showed marked pathological changes. Liver sections demonstrated hepatocellular degeneration, disrupted architecture, and elongated sinusoidal spaces while heart tissues exhibited myofibrillar degeneration and formation of swollen vacuoles. Overall, both Pb and Cu demonstrated significant teratogenic effects with lead showing comparatively greater toxicity. Injection exposure resulted in more pronounced structural and histological abnormalities than immersion indicating that direct embryonic exposure poses a higher developmental risk.

Microbial community restructuring and transcriptional responses to acute stress in duckweed enhance lead phytoremediation.

Ureolytic microbially-induced carbonate precipitation and ureolytic enzymatically-induced carbonate precipitation have been proposed in recent years as emerging environmentally friendly techniques for heavy metal fixation. However, they rely on the hydrolysis of urea for generating carbonate ions needed to immobilize heavy metal cations. In this study, for the first time, a novel alternative is proposed, and its feasibility for lead removal in aqueous solutions is examined. The method relies on direct CO2 biocementation. Where contaminated solutions are exposed to CO2, and CO2 hydration and formation of carbonate ions is biologically facilitated through (I) microbial strains capable of producing carbonic anhydrase enzyme (i.e., microbially-facilitated carbonation, MFC), and (II) an enzymatic solution containing bovine CA enzyme (i.e., enzymatically-facilitated carbonation, EFC). The results of atomic absorption spectrophotometry indicate up to 99% Pb removal achieved in both MFC and EFC, comparable to the control ureolytic test (98%). However, the former (proposed) techniques are ammonium-free and more environmentally benign. Furthermore, they provide a dual environmental benefit: a method for carbon capture through biomineralization and its utilization for heavy metal removal. The use of Tris buffer considerably enhanced the efficiency of enzymatically-facilitated carbonation for Pb removal (i.e., increasing it from 78% to 99%). The results of microfabric analysis of precipitates (i.e., SEM imaging, XRD, FTIR, and Raman spectroscopy) confirmed the formation of calcium and lead carbonates such as calcite, cerussite, and hydrocerussite, indicating potential removal mechanisms such as lead carbonate precipitation as well as Pb trapping inside calcium carbonate crystals.

Lead exposure remains a major global health concern, contributing to an estimated 1.5% of annual deaths worldwide and causing widespread, irreversible neurodevelopmental and cardiovascular damage, particularly in children. A central challenge in understanding and mitigating lead toxicity is the determination of its chemical speciation in complex biological and environmental systems, where conventional Pb LIII-edge X-ray absorption spectroscopy (XAS) is fundamentally limited by severe core-hole lifetime broadening. Here we show that Pb Lα1 high-energy-resolution fluorescence-detected X-ray absorption spectroscopy (HERFD-XAS) provides a practical and experimentally accessible route to overcoming this limitation. Pb Lα1 HERFD-XAS yields an approximately 2-fold improvement in spectral resolution relative to conventional XAS, enabling enhanced sensitivity for quantitative speciation in heterogeneous and dilute systems. The method shows negligible chemical shifts (<0.06 eV) in the emission energy, simplifying implementation, distinguishes holodirected and hemidirected Pb(II) coordination environments, resolves biologically relevant Pb binding modes in zinc-finger model peptides, and identifies hemidirected Pb-substitution in hydroxyapatite, a key long-term reservoir of lead in humans. These results establish Pb Lα1 HERFD-XAS as a sensitive and experimentally accessible tool for determining Pb speciation in environmental and biological systems.

Doping Mn2+ ions into all-inorganic cesium lead halide perovskite nanocrystals (PNCs) offers a unique pathway for inducing a new emission channel and reducing lead toxicity. However, concentration quenching at high Mn2+ levels degrades the photoluminescence quantum yield (PLQY), posing a formidable challenge for reconciling a high Pb substitution rate with a high Mn2+ emission PLQY. In this study, we report an efficient approach for simultaneously achieving 100% PLQY of Mn2+ emission and an 18.58% Pb substitution rate in Mn2+/Sr2+ co-doped CsPbCl3 NCs.This balance between a high PLQY and a high Pb substitution rate is realized by reducing defect density and mitigating lattice distortion through Sr2+ doping, thus enhancing energy transfer efficiency from excitons to Mn2+ (70.85% vs. 87.88%) and alleviating the microstrain induced by lattice distortion to facilitate the occupation of Pb2+ sites. The stability-enhanced Mn/Sr-CsPbCl3@PMMA nanocrystal-polymer composite film was further fabricated for the construction of a white light-emitting diode (WLED), which achieved desirable white-light coordinates (0.338, 0.346). This work not only enriches the understanding of the luminescence properties of Mn2+-doped PNCs but also provides new insights for developing low-toxicity light-emitting devices.

Correlation analysis of lead stress-induced alterations in root metabolome and rhizosphere microbiome of Cuminum cyminum L.

Soil lead (Pb) contamination represents a global environmental challenge, with well-documented adverse effects on both ecosystems and human health. Although Pb-containing nanoparticles (Pb NPs) constitute a significant, yet poorly characterized, fraction of Pb in soils, their origins remain difficult to ascertain due to the chemical complexity of soil matrices and the heterogeneity of Pb contamination sources. In this study, we developed a comprehensive strategy for the characterization and source tracing of Pb NPs in soils using single-particle inductively coupled plasma-mass spectrometry (spICP-MS). First, we established a robust protocol for the qualitative and quantitative characterization of tetrasodium pyrophosphate (TSPP)-extracted Pb NPs from soil samples using spICP-quadrupole-MS (spICP-Q-MS). Then, by leveraging quasi-instantaneous, multi-isotope Pb measurements (206Pb, 207Pb, and 208Pb) at the single-particle level via spICP-time-of-flight-MS (spICP-TOF-MS), we identified the region-specific sources of soilborne Pb NPs across four representative Chinese cities (Beijing, Shaoguan, Xiong'an, and Zhuzhou) by integrating isotopic fingerprinting (208Pb/206Pb and 206Pb/207Pb) with the MixSIAR Bayesian mixing model. Our results demonstrate that Pb NPs can serve as highly sensitive tracers for assessing the extent of soil Pb pollution and for distinguishing geographically distinct Pb contamination sources. We anticipate that this approach will advance the mechanistic understanding of Pb biogeochemistry and improve source apportionment in soil ecosystems.

Lead (Pb2+) toxicity disrupts cellular redox homeostasis and photosynthesis, highlighting the need to uncover the mechanisms underlying Pb2+ tolerance in phytoremediation. In this study, we characterized SlABH15, an α/β-hydrolase gene enhancing Pb2+ tolerance in tomato. SlABH15 was strongly Pb2+-induced (∼30-fold at 24 h) and was localized to the plasma membrane, acting as a methyl jasmonate esterase converting methyl jasmonate (MeJA) to jasmonic acid (JA). Co-immunoprecipitation (Co-IP) revealed that SlABH15 interacts with KAT2, a key peroxisomal enzyme in JA biosynthesis, and this interaction was strongly enhanced by Pb2+ and JA. SlABH15 overexpression improved Pb2+ tolerance, reduced ROS accumulation, sustained photosynthesis, and decreased tissue Pb2+ content. Conversely, silencing SlABH15 reduced JA levels, exacerbated oxidative damage, and repressed genes involved in JA and chlorophyll biosynthesis. Collectively, our results demonstrate that SlABH15 acts as a critical positive regulator integrating MeJA hydrolysis and JA biosynthesis to maintain plant defense and photosynthetic homeostasis under Pb2+ stress.

Dion-Jacobson (DJ) hybrid perovskites are considered as highly promising X-ray detection materials due to their high stability and short interlayer spacing. However, the large-scale commercial development of these materials is challenged due to severe ion migration at high voltage and lead toxicity. Here, we successfully obtained a DJ-type polar lead-free green hybrid perovskite (4AMPY)2AgBiBr8 (1) by inserting 4-aminomethylpyridine (4AMPY) aromatic diamine into 3D Cs2AgBiBr6, and achieved efficient and stable self-powered X-ray detection. Specifically, owing to the insertion of 4AMPY, 1 crystallizes in polar space group P21 and exhibits a significant bulk photovoltaic effect. Additionally, strong hydrogen-bonding interactions between 4AMPY and adjacent inorganic layers lead to an ultranarrow interlayer spacing of 3.09 Å. Meanwhile, the enhanced electron cloud density in aromatic diamines improves the charge transfer channel of 1 and enhances its X-ray detection performance. Therefore, among all DJ-type lead-free hybrid perovskites, 1 achieves record-breaking sensitivities of 661.4 and 9465.2 µC Gy-1 cm-2 at 0 and 100V, respectively. Importantly, 1 exhibits excellent storage stability, with its sensitivity remaining at 97.5% (0V) and 96.6% (100V) of the initial value after three months. This work will greatly promote the development of polar DJ-type lead-free perovskite-based self-powered X-ray detectors.

Childhood lead toxicity remains a nationwide problem, despite significant progress in reducing exposure sources in the United States since the 1970s. Neurodevelopmental sequelae of lead exposures often persist into adulthood, with limited reversibility. These include long-lasting deficits in intelligence, impulse control, and emotional and behavioral regulation, which can increase one's propensity for aggression and criminality. Yet, despite the strong association between lead poisoning and criminality, there is little agreement thus far among U.S. jurisdictions about how to apply such knowledge to criminal legal proceedings. Here, we explore forensic considerations of childhood lead toxicity for evaluation, sentencing, and staff support in the criminal justice system. We cite both clinical science and case law in navigating this complex intersection of forensic psychiatry, public health, and the environment. We aim to provide preliminary guidance on how forensic psychiatrists can approach and refer to lead toxicity in their medicolegal work. This article may hopefully inspire further forensic research on the topic and the eventual creation of standardized, lead-related guidelines for criminal legal proceedings.