Nanomaterials for sustainable remediation: efficient removal of Rhodamine B and lead using greenly synthesized novel mesoporous ZnO@CTAB nanocomposite.

This study explores the dual applications of a greenly synthesized ZnO@CTAB nanocomposite for the efficient remediation of Rhodamine B (RhB) and lead (Pb). The synthesis method involves a sustainable approach, emphasizing environmentally friendly practices. FT-IR, XRD, FESEM, zeta potential, and particle size analyzer (PSA), BET, and UV-VIS were used to physically characterize the zinc oxide and CTAB nanocomposite (ZnO@CTAB). The size and crystalline index of ZnO@CTAB are 77.941 nm and 63.56% respectively. The Zeta potential of ZnO@CTAB is about - 22.4 mV. The pore diameter of the ZnO@CTAB was 3.216 nm, and its total surface area was 97.42 m2/g. The mechanism of adsorption was investigated through pHZPC measurements. The nanocomposite's adsorption performance was systematically investigated through batch adsorption experiments. At pH 2, adsorbent dose of 0.025 g, and temperature 50 °C, ZnO@CTAB removed the most RhB, while at pH 6, adsorbent dose of 0.11 g, and temperature 60 °C, ZnO@CTAB removed the most Pb. With an adsorption efficiency of 214.59 mg/g and 128.86 mg/g for RhB and Pb, the Langmuir isotherm model outperforms the Freundlich isotherm model in terms of adsorption. The pseudo-2nd-order model with an R2 of 0.99 for both RhB and Pb offers a more convincing explanation of adsorption than the pseudo-1st-order model. The results demonstrated rapid adsorption kinetics and high adsorption capacities for RhB and Pb. Furthermore, there was minimal deterioration and a high reusability of ZnO@CTAB till 4 cycles were observed.

Effect of oxygen-containing functional group contents on sorption of lead ions by acrylate-functionalized hydrochar.

The surface functional groups of hydrochar are crucial to its surface properties, and their contents are strongly positively correlated with the adsorption performance. In this study, acrylate-functionalized hydrochar (AHC) with varying contents of O-containing functional groups (OFGs) was synthesized via hydrothermal carbonization (HTC) of bamboo, acrylic acid and an initiator, and then deprotonated with NaOH. The AHCs were analyzed by various characterization techniques. During HTC, the higher amount of acrylic acid added led to higher carbon, oxygen and carboxyl contents, and to the larger specific surface area and pore volume of AHC. The adsorption kinetics, isotherms, thermodynamic, ionic strength and pH effects of Pb(II) on AHC were studied. Adsorption isotherms and kinetics obeyed Langmuir and pseudo-second-order models, respectively, indicating adsorption is monolayer chemical process. The adsorptive ability was well linearly related to the OFG contents of AHC. When acrylic acid was added to 25 mL during HTC, the adsorbing ability of AHC over Pb(II) reached 193.90 mg g-1. Hence, direct HTC of acrylic acid, biomass and an initiator can prepare hydrochar with controllable OFG contents, which is a prospective adsorbent for treating metal cations.

Synthesis of surface-modified porous polysulfides from soybean oil by inverse vulcanization and its sorption behavior for Pb(II), Cu(II), and Cr(III).

Guided by efficient utilization of natural plant oil and sulfur as low-cost sorbents, it is desired to tailor the porosity and composition of polysulfides to achieve their optimal applications in the management of aquatic heavy metal pollution. In this study, polysulfides derived from soybean oil and sulfur (PSSs) with improved porosity (10.2-22.9 m2/g) and surface oxygen content (3.1-7.0 wt.%) were prepared with respect to reaction time of 60 min, reaction temperature of 170 °C, and mass ratios of sulfur/soybean oil/NaCl/sodium citrate of 1:1:3:2. The sorption behaviors of PSSs under various hydrochemical conditions such as contact time, pH, ionic strength, coexisting cations and anions, temperature were systematically investigated. PSSs presented a fast sorption kinetic (5.0 h) and obviously improved maximum sorption capacities for Pb(II) (180.5 mg/g), Cu(II) (49.4 mg/g), and Cr(III) (37.0 mg/g) at pH 5.0 and T 298 K, in comparison with polymers made without NaCl/sodium citrate. This study provided a valuable reference for the facile preparation of functional polysulfides as well as a meaningful option for the removal of aquatic heavy metals.

Powdered and beaded sawdust materials modified iron (III) oxide-hydroxide for adsorption of lead (II) ion and reactive blue 4 dye.

The problems of lead and reactive blue 4 (RB4) dye contamination in wastewater are concerns because of their toxicities to aquatic life and water quality, so lead and RB4 dye removals are recommended to remove from wastewater before discharging. Sawdust powder (SP), sawdust powder doped iron (III) oxide-hydroxide (SPF), sawdust beads (SPB), and sawdust powder doped iron (III) oxide-hydroxide beads (SPFB) were synthesized and characterized with various techniques, and their lead or RB4 dye removal efficiencies were investigated by batch experiments, adsorption isotherms, kinetics, and desorption experiments. SPFB demonstrated higher specific surface area (11.020 m2 g-1) and smaller pore size (3.937 nm) than other materials. SP and SPF were irregular shapes with heterogeneous structures whereas SPB and SPFB had spherical shapes with coarse surfaces. Calcium (Ca) and oxygen (O) were found in all materials whereas iron (Fe) was only found in SPF and SPFB. O-H, C-H, C=C, and C-O were detected in all materials. Their lead removal efficiencies of all materials were higher than 82%, and RB4 dye removal efficiencies of SPB and SPFB were higher than 87%. Therefore, adding iron (III) oxide-hydroxide and changing material form helped to improve material efficiencies for lead or RB4 dye adsorption. SP and SPB corresponded to Langmuir model related to a physical adsorption process whereas SPF and SPFB corresponded to the Freundlich model correlated to a chemisorption process. All materials corresponded to a pseudo-second-order kinetic model relating to the chemical adsorption process. All materials could be reused more than 5 cycles with high lead removal of 63%, and SPB and SPFB also could be reused more than 5 cycles for high RB4 dye removal of 72%. Therefore, SPFB was a potential material to apply for lead or RB4 dye removal in industrial applications.

Highly Luminescent, Stable, and Red-Emitting CsMgxPb1-xI3 Quantum Dots for Dual-Modal Imaging-Guided Photodynamic Therapy and Photocatalytic Activity.

In this study, for the first time, red-emitting CsMgxPb1-xI3 quantum dots (QDs) are prepared by doping with magnesium (Mg) ions via the one-pot microwave pyrolysis technique. The X-ray diffraction and X-ray photoelectron spectroscopy results have confirmed partial substitution of Pb2+ by Mg2+ inside the CsPbI3 framework. The as-synthesized CsMgxPb1-xI3 QDs have exhibited excellent morphology, higher quantum yield (upto ∼89%), better photostability and storage stability than undoped CsPbI3. Next, the bioavailability of as-synthesized hydrophobic CsMgxPb1-xI3 QDs is improved by encapsulating them into gadolinium-conjugated pluronic 127 (PF127-Gd) micelles through hydrophobic interactions (PQD@Gd). The optical properties of perovskite quantum dots (PQDs) and the presence of Gd could endow the PQD@Gd with fluorescence imaging, magnetic resonance imaging (MRI), and phototherapeutic properties. Accordingly, the MRI contrasting effects of PQD@Gd nanoagents are demonstrated by employing T1 and T2 studies, which validated that PQD@Gd nanoagents had superior MR contrasting effect with a r2/r1 ratio of 1.38. In vitro MRI and fluorescence imaging analyses have shown that the PQD@Gd nanoagents are internalized into the cancer cells via a caveolae-mediated endocytosis pathway. The PQD@Gd nanoagents have exhibited excellent biocompatibility even at concentrations as high as 450 ppm. Interestingly, the as-prepared PQD@Gd nanoagents have efficiently produced cytotoxic reactive oxygen species in the cancer cells under 671 nm laser illumination and thereby induced cell death. Moreover, the PQD@Gd nanoagent also demonstrated excellent photocatalytic activity toward organic pollutants under visible light irradiation. The organic pollutants rhodamine b, methyl orange, and methylene blue were degraded by 92.11, 89.21, and 76.21%, respectively, under 60, 80, and 100 min, respectively, irradiation time. The plausible mechanism for the photocatalytic activity is also elucidated. Overall, this work proposes a novel strategy to enhance the optical properties, stability, and bioapplicability of PQDs. The multifunctional PQD@Gd nanoagents developed in this study could be the potential choice of components not only for cancer therapy due to dual-modal imaging and photodynamic therapeutic properties but also for organic pollutant or bacterial removal due to excellent photocatalytic properties.

Open Reading Frame 1 Protein of the Human Long Interspersed Nuclear Element 1 Retrotransposon Binds Multiple Equivalents of Lead.

The human long interspersed nuclear element 1 (LINE1) has been implicated in numerous diseases and has been suggested to play a significant role in genetic evolution. Open reading frame 1 protein (ORF1p) is one of the two proteins encoded in this self-replicating mobile genetic element, both of which are essential for retrotransposition. The structure of the three-stranded coiled-coil domain of ORF1p was recently solved and showed the presence of tris-cysteine layers in the interior of the coiled-coil that could function as metal binding sites. Here, we demonstrate that ORF1p binds Pb(II). We designed a model peptide, GRCSL16CL23C, to mimic two of the ORF1p Cys3 layers and crystallized the peptide both as the apo-form and in the presence of Pb(II). Structural comparison of the ORF1p with apo-(GRCSL16CL23C)3 shows very similar Cys3 layers, preorganized for Pb(II) binding. We propose that exposure to heavy metals, such as lead, could influence directly the structural parameters of ORF1p and thus impact the overall LINE1 retrotransposition frequency, directly relating heavy metal exposure to genetic modification.

The Connection between Czc and Cad Systems Involved in Cadmium Resistance in Pseudomonas putida.

Heavy metal pollution is widespread and persistent, and causes serious harm to the environment. Pseudomonas putida, a representative environmental microorganism, has strong resistance to heavy metals due to its multiple efflux systems. Although the functions of many efflux systems have been well-studied, the relationship between them remains unclear. Here, the relationship between the Czc and Cad systems that are predominantly responsible for cadmium efflux in P. putida KT2440 is identified. The results demonstrated that CzcR3, the response regulator of two-component system CzcRS3 in the Czc system, activates the expression of efflux pump genes czcCBA1 and czcCBA2 by directly binding to their promoters, thereby helping the strain resist cadmium stress. CzcR3 can also bind to its own promoter, but it has only a weak regulatory effect. The high-level expression of czcRS3 needs to be induced by Cd2+, and this relies on the regulation of CadR, a key regulator in the Cad system, which showed affinity to czcRS3 promoter. Our study indicates that the Cad system is involved in the regulation of the Czc system, and this relationship is important for maintaining the considerable resistance to cadmium in P. putida.

Cesium Lead Bromide (CsPbBr3) Perovskite Quantum Dot-Based Photosensor for Chemiluminescence Immunoassays.

Chemiluminescence immunoassays have been widely employed for diagnosing various diseases. However, because of the extremely low intensity chemiluminescence signals, highly sensitive transducers, such as photomultiplier tubes and image sensors with cooling devices, are required to overcome this drawback. In this study, a hypersensitive photosensor was developed based on cesium lead bromide (CsPbBr3) perovskite quantum dots (QDs) with sufficient high sensitivity for chemiluminescence immunoassays. First, CsPbBr3 QDs with a highly uniform size, that is, 5 nm, were synthesized under thermodynamic control to achieve a high size confinement effect. For the fabrication of the photosensor, MoS2 nanoflakes were used as an electron transfer layer and heat-treated at an optimum temperature. Additionally, a parylene-C film was used as a passivation layer to improve the physical stability and sensitivity of the photosensor. In particular, the trap states on the CsPbBr3 QDs were reduced by the passivation layer, and the sensitivity was increased. Finally, a photosensor based on CsPbBr3 QDs was employed in chemiluminescence immunoassays for the detection of human hepatitis B surface antigen, human immunodeficiency virus antibody, and alpha-fetoprotein (AFP, a cancer biomarker). When compared with the conventionally used equipment, the photosensor was determined to be feasible for application in chemiluminescence immunoassays.

Dietary risk of milk contaminated with lead and cadmium in areas near mining-metallurgical industries in the Central Andes of Peru.

The mining-metallurgical industry in the central Andes of Peru is a source of lead (Pb) and cadmium (Cd) contamination in milk, and there are no studies on the impact of their ingestion. Using flame atomic absorption spectrometry, we quantified the concentration of these metals in raw milk produced in agroecological zones near these industries, and estimated the exposure and dietary risk in people aged 2-85 yr with minimum, average and maximum daily milk intake. In 2018, 40 raw milk samples were collected from 20 cows at two times of the year. The mean Pb and Cd concentrations were 577 ± 18.2 and 18.35 ± 5.4 µg/kg, all samples exceeded the maximum limits (ML). Children aged 2-5 and 6-15 yr, with average milk consumption, had Pb weekly intakes (WI) of 2019 and 2423 µg, exceeding the risk value; values for Cd 64 and 77 µg were below the risk values. In those older than 20 years the WI for both metals are below the risk values. The Dietary Risk Coefficient (DRC) to Pb in children younger than 8 years was >3 due to higher milk consumption in relation to body weight; for children aged 9-19 years it was 1.7 and 2.9, being <1 for those older than 20 yr. Cd RDCs were <1 at all ages, with the exception of 2-year-olds in the high milk consumption scenario (RDC > 1). There was notable evidence of Pb and Cd exposure risk from consumption of milk produced near mining-metallurgical activities, predominantly for children under 19-year-olds. In Peru there are no regulations for Pb and Cd in fresh milk and milk products, we recommended that ML for heavy metals in food be established.

Soil cadmium and lead affecting biochemical properties of Matricaria chamomilla L. at different growth stages in the greenhouse and field.

Heavy metals bioremediation by medicinal plants is an important research issue, which has yet to be investigated. Matricaria chamomilla accumulation of soil cadmium (Cd, 0, 10 and 40 mg/kg) and lead (Pb, 0, 60 and 180 mg/kg) affecting plant biochemical properties L. at different growth stages in the greenhouse and field was investigated. The 10-kg experimental pots (located in the greenhouse and field with 80% of field capacity moisture) were filled with the treated soils, and were planted with M. chamomilla L. seeds (three replicates). Plants were sampled to determine their biochemical properties including Cd and Pb contents, pigments, proline (Pro), leaf relative water (LRW), lipid peroxidation (LX), and superoxide dismutase (SOD, EC 1.15. 1.1), and catalase (CAT, EC 1.11.1.6) activities. Soil final concentration of Cd and Pb was also determined. Heavy metal stress significantly decreased plant pigment contents; however, it significantly increased plant PRO, LRW, LX and SOD, and not CAT. Heavy metal, growth stage, growth location, and their interactions significantly affected plant heavy metal concentrations. Interestingly, although significantly higher concentration of Cd was observed in plant aerial part under greenhouse conditions, plant roots had significantly higher concentrations of Cd under field conditions, and it was reverse for Pb. Increased concentration of Cd and Pb significantly enhanced plant Pro content and the highest one was resulted by Pb3 (913.46 mg/g fresh weight) significantly higher than other treatments including Cd3 (595.34 mg/g fresh weight). M. chamomilla is a suitable species for the bioremediation of soils polluted with Cd and Pb.

Evaluation of monoxide film-based dosimeters for surface dose detection in electron therapy.

Generally, electron therapy is applied to tumors on or close to the skin surface. However, this causes a variety of skin-related side effects. To alleviate the risk of these side effects, clinical treatment uses skin dosimeters to verify the therapeutic dose. However, dosimeters suffer from poor accuracy, because their attachment sites are approximated with the help of naked eyes. Therefore, a dosimeter based on a flexible material that can adjust to the contours of the human body is required. In this study, the reproducibility, linearity, dose-rate dependence, and percentage depth ionization (PDI) of PbO and HgO film-based dosimeters are evaluated to explore their potential as large-scale flexible dosimeters. The results demonstrate that both dosimeters deliver impressive reproducibility (within 1.5%) and linearity (≥ 0.9990). The relative standard deviations of the dose-rate dependence of the PbO and HgO dosimeters were 0.94% and 1.16% at 6 MeV, respectively, and 1.08% and 1.25% at 9 MeV, respectively, with the PbO dosimeter outperforming the 1.1% of existing diodes. The PDI analysis of the PbO and HgO dosimeters returned values of 0.014 cm (-0.074 cm) and 0.051 cm (-0.016 cm), respectively at 6 MeV (9 MeV) compared to the thimble chamber and R50. Therefore, the maximum error of each dosimeter is within the allowable range of 0.1 cm. In short, the analysis reveals that the PbO dosimeter delivers a superior performance relative to its HgO counterpart and has strong potential for use as a surface dosimeter. Thus, flexible monoxide materials have the necessary qualities to be used for dosimeters that meet the requisite quality assurance standards and can satisfy a variety of radiation-related applications as flexible functional materials.

Changes induced by lead in root system architecture of Arabidopsis seedlings are mediated by PDR2-LPR1/2 phosphate dependent way.

As sessile organisms, plants respond to changing environments modulating their genetic expression, metabolism and postembryonic developmental program (PDP) to adapt. Among environmental stressor, lead (Pb) is one of the most hazardous pollutants which limits crop productivity. Here, we describe in detail the effects of a wide range of concentrations of Pb on growth and development and a possible convergence with phosphate (Pi) starvation response. We found that the response to Pb presents a biphasic curve dose response in biomass accumulation: below 400 µM show a stimulatory effect meanwhile at Pb doses up to 600 µM effects are inhibitory. We found that +Pb (800 µM) modifies root system architecture (RSA) and induces acidification media, according to in silico ion interaction, in the growing medium Pb and Pi coprecipitate and plants grow in both Pi deficiency and Pb stress at the same time, however in spite of seedlings are under Pi starvation AtPT2 expression are Pb downregulated indicating that in addition to Pi starvation stress, Pb regulates physiological responses in root system. Using the mutants stop1, lpr1/2 and lpi3, which are affected in Pi starvation response, we found that changes in RSA by +Pb is genetically regulated and there are shared pathways with Pi starvation response mediated by PDR2-LPR1/2 and LPI3 pathways since lpr1/2 and lpi3 mutants are insensitive to +Pb and Pi starvation. Taking together, these results indicate that similar changes in RSA induced by independent environmental stimuli +Pb and Pi starvation are due to similar mediated response by PDR2-LPR1/2 pathway.

Effect of modified fly ash on environmental safety of two soils contaminated with cadmium and lead.

In this study, a low-temperature roasting and hydrothermal methods were used to modify the fly ash resulting in two new types of adsorption materials - modified fly ash (MFA) and artificial zeolite (ZE). These modified fly ashes, as well as a natural zeolite (ZO) were applied to two types of contaminated soils to explore their effects and mechanisms on the behavior of Cd and Pb through leaching column experiments. The bioavailable of Pb, Cd, pH, dissolved organic carbon (DOC), organic matter, as well as the microbial community changings were detected. The results showed that, 2% ZE has a significant stabilizing effect on Cd and the bioavailable fraction contents in Guanzhong (GZ) and Hunan (HN) soils decreased by 40.5% and 53.2%, respectively. However, for Pb, the 2% MFA showed a better result than that of ZE and ZO; the contents of bioavailable Pb in HN and GZ decreased by 48.3% and 30%, respectively. Furthermore, based on the Illumina NovaSep sequencing platform, 18 soil samples of GZ and HN were sequenced for microbial communities. As compared to the control blank(CK) treatment, the abundance of soil microbial communities was significantly improved in the amended soils.

Bacterial synthesis of PbS nanocrystallites in one-step with L-cysteine serving as both sulfur source and capping ligand.

The green bacterial biosynthesis of lead sulfide nanocrystallites by L-cysteine-desulfurizing bacterium Lysinibacillus sphaericus SH72 was demonstrated in this work. Nanocrystals formed by this bacterial method were characterized using the mineralogical and morphological approaches. The results revealed that the microbially synthesized PbS nanocrystals assume a cubic structure, and are often aggregated as spheroids of about 105 nm in size. These spheroids are composed of numerous nanoparticles with diameter 5-10 nm. Surface characterization of the bacterial nanoparticles with FTIR spectroscopy shows that the L-cysteine coats the surface of PbS nanoparticle as a stabilizing ligand. The optical features of the PbS nanocrystallites were assessed by UV-Vis spectroscopy and PL spectroscopy. The maximum absorption wavelength of the bacterial PbS particles occurs at 240 nm, and the photoluminescence emission band ranges from 375 to 550 nm. The band gap energy is calculated to be 4.36 eV, compared to 0.41 eV for the naturally occurring bulk PbS, with this clear blue shift attributable to the quantum size effect.

Colorimetric sensing of chloride in sweat based on fluorescence wavelength shift via halide exchange of CsPbBr3 perovskite nanocrystals.

Considering the high importance of the rapid detection of chloride ion (Cl-) in sweat for the diagnosis of fibrotic cysts, we have investigated the heterogeneous halide exchange between CsPbBr3 perovskite nanocrystals (PNCs) in n-hexane and Cl- in aqueous solution. The results show that CsPbBr3 PNCs could achieve fast halide exchange with Cl- in the aqueous phase under magnetic stirring at pH = 1, accompanied by a significant wavelength blue shift and vivid fluorescence color changes from green to blue. Therefore, a fluorescence wavelength shift-based colorimetric sensing of Cl- based on the halide exchange of CsPbBr3 PNCs has been developed to realize the rapid detection of Cl- in sweat. Compared with the conventional fluorescence intensity-based method, this method is of high convenience since the whole procedure could be achieved within 5 min without any sample pretreatment (even no dilution), demonstrating promising application prospects. Graphical Abstract Fluorescence wavelength-shift based colorimetric sensing of chloride in sweat via halide exchange of CsPbBr3 perovskite nanocrystals.

Simultaneous determination of cadmium, lead and copper in chocolate samples by square wave anodic stripping voltammetry.

In this work, an effective and simple method is proposed for the simultaneous determination of cadmium, lead and copper in chocolate samples by Square Wave Anodic Stripping Voltammetry (SWASV). An ultrasonic bath was used for the extraction of cadmium, lead and copper from fourteen chocolate samples using HNO3 solution (7 mol L-1). The electrochemical system consisted of a cell with three electrodes and HCl solution (10 mmol L-1) as the supporting electrolyte. An efficient extraction of the metals (~100%) was attained after 1 h of ultrasonic pre-treatment. Quantitative analysis was carried out by the standard addition method. Good linearity, precision and accuracy were obtained in the range of concentrations examined. The accuracy was evaluated by means of a reference sample of spiked skim milk powder (BCR 151) to prove the reliability of the method. Detection limits (LOD) of 0.089, 0.059 and 0.018 µg g-1 were found for cadmium, copper and lead, respectively, in the chocolate samples. Concentrations in chocolate samples were 4.30-138 µg g-1 for Cu and 0.83-27.9 µg g-1 for Pb, with no significant Cd. The simultaneous determination brings advantages to other methods already reported for chocolate analysis and the samples preparation proposed avoids the traditional sample mineralization step. These characteristics show this new method is especially attractive for case studies and routine analysis.

Sorption mechanisms of lead on soil-derived black carbon formed under varying cultivation systems.

The knowledge about lead (Pb) sorption on soil-derived black carbons (SBCs) under different cultivation intensities of soils is limited. In this study, chemical and spectroscopic methods were applied to investigate the Pb sorption mechanisms on SBCs in soils from a forest land, a rubber plantation area, and a vegetable farm with none, less and highly intensive cultivation, respectively, that are located in the Hainan Island of China. Results showed that the specific surface area and cation exchange capacity of the SBCs from the less and highly intensive cultivation soils were 4.5- and 2.7-fold, and 1.3- and 1.8-fold higher compared to that of SBC from the no-cultivation soil, which subsequently enhanced the Pb sorption capacities of SBCs in iron exchange fraction. Ion exchange and hydrogen bonded Pb fractions together accounted for about 80% of total Pb sorbed on all SBCs at an externally added 1000 mg L-1 Pb solution concentration. The OC-O groups also played key roles in Pb sorption by forming complexes of OC-O-Pb-O and/or OC-O-Pb. Overall, SBCs in soils under all studied cultivation intensities showed high potential to sorb Pb (with the maximum absorbed Pb amount of 46.0-91.3 mg g-1), and increased Pb sorption capacities of the studied soils by 18.7-21.1 mg kg-1 in the stable fraction (complexation). Therefore, SBC might be a potential environment-friendly material to enhance the Pb immobilization capacity of soil.

Health risk indices and zooplankton-based assessment of a tropical rainforest river contaminated with iron, lead, cadmium, and chromium.

Oil exploration's devastation on health and the environment may far outweigh its economic benefits. An oil spill occurred at Egbokodo River in Delta State, Nigeria, thereby polluting the land and water bodies. The study was therefore aimed at evaluating the impacts of iron, lead, cadmium, and chromium on the zooplankton community structure of Egbokodo River and the potential health risks. Zooplankton and surface water samples were collected to investigate the concentrations of trace metals and zooplankton abundance. The associated carcinogenic and non-carcinogenic effects of the metals in the water were analyzed. Trace metal concentrations in the surface water were determined using atomic absorption spectroscopy (Philips model PU 9100) and zooplankton samples were collected using a hydrobios plankton net (mesh size 25 µm). Total petroleum hydrocarbons (TPH) and oil and grease (OG) were determined using Agilent 7890B gas chromatography coupled to flame ionization detector (GC-FID) and volumetric analysis respectively. The trend of the abundance of zooplanktons cross the river was 18 individuals (Station A) < 100 individuals (Station B) < 155 individuals (Station C). Cyclopoida proved to be the most resilient to the impacts of the oil spill. On a taxa basis, the order of abundance among Calanoida, Cyclopoida, Cladoceran, and Harpacticoida was Station C > Station B > Station A, except in Amphipoda where Station B > Station C > Station A was observed. Iron and lead posed significant carcinogenic risks that are liable to be inflicted by the ingestion of the water. The cumulative non-carcinogenic health risk in the male was the only significant (> 1) among the age groups. Total petroleum hydrocarbons (TPH), oil and grease (OG), iron, and lead had notable impacts on the general abundance of zooplankton in the aquatic habitat. The dominance of the Cyclopoida in the river buttressed the impact of the oil spill which warrants a prompt remediation measure. The pollution had notable ecological impacts on the zooplankton community structure of the aquatic habitat. The adults in the nearby human populations are liable to elicit carcinogenic health challenges associated with lead and iron ingestion. The males are at risk of non-carcinogenic illnesses which are associated with the combined toxicity effects of all the metals. The study suggests that the pollution in Egbokodo River was validated by the dominance of the Cyclopoida in the aquatic habitat. The study confers bioindicator reputation on the Cyclopoida for future biomonitoring studies.

Highly luminescent biocompatible CsPbBr3@SiO2 core-shell nanoprobes for bioimaging and drug delivery.

The encapsulation of lead halide perovskite nanocrystals (PNCs) with an inert protective layer against moisture and the environment is a promising approach to overcome hinderances for their practical use in optoelectronic and biomedical applications. Herein, a facile method for synthesizing highly luminescent and biocompatible CsPbBr3@SiO2 core-shell PNCs with a controlled SiO2 thickness, which are suitable for both cell imaging and drug delivery, is reported. The synthesized CsPbBr3@SiO2 core-shell PNCs exhibit bright green emission at 518 nm upon excitation of 374 nm. Interestingly, a significant increase in the photoluminescence intensity is observed with an increase in the SiO2 shell thickness, which varies with the increasing reaction time. Cytotoxicity results indicate that the CsPbBr3@SiO2 core-shell PNCs are nontoxic, making them suitable for in vitro cell imaging using HeLa cells. Furthermore, doxorubicin physically adsorbed on the surface of CsPbBr3@SiO2 core-shell PNCs is efficiently released in cells when the drug-loaded perovskite nanoprobes are injected in the cells, indicating that these core-shell nanoparticles can be used for drug loading and delivery. The results of this study suggest that the CsPbBr3@SiO2 core-shell PNCs can pave the way for new biomedical applications and processes.