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Phytoremediation is an in situ, low-cost strategy for cleanup of the sites contaminated with heavy metals. Experiments were conducted to assess the impact of synthetic chelators and plant growth-promoting rhizosphere bacteria (Herbaspirillum sp. GW103) on heavy metal lead (Pb) uptake in Z. mays cultivated in Pb-contaminated soil. The present study investigated the Pb phytoaccumulation rate and plant antioxidant enzyme activities in Z. mays exposed to 100 mg/kg of PbNO3. The combination of gluconic acid (GA) with Herbaspirillum sp. GW103 treatment showed higher Pb solubility (18.9 mg/kg) compared with other chelators. The chemical chelators showed the significant difference in phytoaccumulation as well as antioxidant enzyme activities. The antioxidant enzymes such as catalase, peroxidase and superoxide dismutase activities changed under Pb stress. The study indicated that increased activity of antioxidant enzymes may play as signal inducers to fight against Pb.

We present a novel and in-situ strategy to synthesize silver nanoparticles (AgNPs) onto cotton, leather, and silk fabrics by three different methods: a green method, a chemical method, and a composite of the green and chemical methods. The in-situ green synthesis was achieved with Aegle marmelos fruit pulp extract while the chemical synthesis utilized NaOH. To validate the green synthesis of AgNPs, various instrumental techniques were used including UV–Vis spectrophotometry, HR-TEM, FTIR, and XRD. The chemical and composite methods reduce Ag+ onto cotton, leather, and silk fabrics upon heating, and alkaline conditions are required for bonding to fibers; these conditions are not used in the green synthesis protocol. The composite technique used to bond AgNPs onto various fabrics provides significant color coordination, color fastness, bulk properties of the leather, and excellent antibacterial activity. In addition, FE-SEM images show the binding patterns of AgNPs on the fabric specimens.

The aim of the study was to isolate and characterize potential multi-metal-resistant bacteria from ore soils. A total of three bacteria were isolated and assayed for resistance to arsenic (As), copper (Cu), and lead (Pb). Isolate Halomonas sp. MG exhibited maximum resistance to 1000 mg Pb/L, 800 mg As/L, and 500 mg Cu/L and it was identified as Halomonas sp. based on the partial 16S rDNA sequences. The metal(loid)s resistance mechanisms were further confirmed by amplification of arsC (As) copAU (Cu), and pbrT (Pb) genes. Biological transmission electron micrographs and XRD studies showed that the isolate Halomonas sp. MG transformed and/or biomineralized the metals either intracellularly or extracellularly. These results suggest that the isolate could be used as a potential candidate for the bioremediation of As, Cu, and Pb.

Previous studies have demonstrated that somatosensory stimuli influence dopamine transmission in the mesolimbic reward system and can reduce drug-induced motor behaviors, craving and dependence. Until now, the central links between somatosensory and brain reward systems are not known. Here, we show that the dorsal column (DC) somatosensory pathway contains projections that convey an inhibitory input from the periphery to mesolimbic reward circuits. Stimulation of the ulnar nerve under HT7 acupoint suppressed psychomotor response to cocaine, which was abolished by disruption of the DC pathway, but not the spinothalamic tract (STT). Low-threshold or wide-dynamic range neurons in the cuneate nucleus (CN) were excited by peripheral stimulation. Lesions of dorsal column or lateral habenula (LHb) prevented the inhibitory effects of peripheral stimulation on cocaine-induced neuronal activation in the nucleus accumbens (NAc). LHb neurons projecting to the ventral tegmental area (VTA)/rostromedial tegmental nucleus (RMTg) regions were activated by peripheral stimulation and LHb lesions reversed the inhibitory effects on cocaine locomotion produced by peripheral stimulation. These findings suggest that there exists a pathway in spinal cord that ascends from periphery to mesolimbic reward circuits (spino-mesolimbic pathway) and the activation of somatosensory input transmitted via the DC pathway can inhibit the psychomotor response to cocaine.

Heavy metal contamination of soil and water from industrial sources remains a worldwide environmental concern. Concentrations of toxic metals were measured in soil from banks of the Han and Anyang rivers. Pre-monsoon samples contained the highest heavy metal concentrations (Cu > As > Pb > Cd > Cr 6+ ; up to 57.80, 38.23, 25.43, 2.21, 0.32 mg/kg, respectively), but concentrations decreased at all sites during the monsoon and post-monsoon seasons. Higher heavy metal concentrations in pre-monsoon samples may be attributed to dust pollution, especially from roads near the river. A gradual reduction in heavy metal concentrations during the rainy season may be due to washing out. The high concentration of metals could cause health problems, especially in residential areas.

The effectiveness of nanoscale zero-valent iron (nZVI) to remove heavy metals from water is reduced by its low durability, poor mechanical strength, and tendency to form aggregates. A composite of zeolite and nanoscale zero-valent iron (Z–nZVI) overcomes these problems and shows good potential to remove Pb from water. FTIR spectra support nZVI loading onto the zeolite and reduced Fe 0 oxidation in the Z–nZVI composite. Scanning electron micrographs show aggregation was eliminated and transmission electron micrographs show well-dispersed nZVI in chain-like structures within the zeolite matrix. The mean surface area of the composite was 80.37 m 2 /g, much greater than zeolite (1.03 m 2 /g) or nZVI (12.25 m 2 /g) alone, as determined by BET-N 2 measurement. More than 96% of the Pb(II) was removed from 100 mL of solution containing 100 mg Pb(II)/L within 140 min of mixing with 0.1 g Z–nZVI. Tests with solution containing 1000 mg Pb(II)/L suggested that the capacity of the Z–nZVI is about 806 mg Pb(II)/g. Energy-dispersive X-ray spectroscopy showed the presence of Fe in the composite; X-ray diffraction confirmed formation and immobilization of Fe 0 and subsequent sorption and reduction of some of the Pb(II) to Pb 0 . The low quantity of Pb(II) recovered in water-soluble and Ca(NO 3 ) 2 -extractable fractions indicate low bioavailability of the Pb(II) removed by the composite. Results support the potential use of the Z–nZVI composite in permeable reactive barriers.

Pollution due to heavy metals and dyes has become a major global environmental issue. Simultaneous removal of heavy metals and dyes from wastewater remains a major challenge. In this study, a zeolite supported nano-scale zero-valent iron (Z-nZVI) composite was innovatively used for the simultaneous removal of Cr(VI) and Reactive Black 5 from aqueous solution. Experiments were carried out at different pH values (2–8) and adsorbent dosages (0.2–1 g L−1). The maximum removal was found to be 99% for both Cr(VI) and Reactive Black 5 (RB5) at pH 3 with initial RB5 concentration 85 mg L−1, Cr(VI) concentration 23 mg L−1 and adsorbent dosage 1 g L−1. A Freundlich model showed a satisfactory fit to the equilibrium adsorption data of a Z-nZVI composite with a correlation coefficient R 2 = 0.9790 for RB5 and R 2 = 0.9726 for Cr(VI). The kinetics of adsorption followed a pseudo-first-order model. The results of the study indicated that a Z-nZVI composite could potentially be used for the simultaneous removal of metals and dyes from wastewater.

A complex Remazol dye effluent, comprised of Remazol Brilliant Blue R, Remazol Black, Remazol Violet, Remazol Orange, sodium chloride, sodium carbonate, sodium hydroxide, and acetic acid, was decolorized using polyaniline/extracellular polymeric substance (Pn/EPS) composite. Scanning electron micrograph showed that the surface of the composite was rough with granular appearance, providing a good possibility for dyes adsorption. X-ray diffractogram (XRD) of the composite showed the main reflections of both Pn and EPSs (2θ = 6.0, 20.1 and 26.2, 30.4, and 40.8). Experiments were carried out as a function of contact time, pH, and adsorbent dose. Under optimized conditions, the maximum percentage removal was found to be 99.8% for the complex Remazol effluent. The Freundlich isotherm model and pseudo first-order rate expression showed satisfactory fit to the equilibrium biosorption data of Pn/EPS composite. Fourier transform infrared spectroscopy, XRD, and desorption studies confirmed the involvement of aromatic, amino, hydroxyl, and carboxylic groups in dye adsorption. The results indicate that composite is suitable as an adsorbent material for the enhanced removal of dyes from complex Remazol effluent.