Geometry of Zn(II) complexes with dissolved organic matter: X-ray studies at variable pH

The structure of Zn(II) complexes with dissolved organic matter (DOM) is an important consideration in developing molecular-level models of Zn(II) speciation, but recent reports favoring the tetrahedral geometry differ from earlier findings that geometry was largely octahedral. In general, the presence of thiolate ligands favors the tetrahedral geometry, while O and N ligands favor the octahedral geometry. This work presents extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) spectroscopic results, indicating an octahedral geometry over the pH range of 5–9 for a freshwater DOM isolate. Changes in XANES derivatives as a function of pH can be explained in terms of ligand protonation and/or changing ligand groups. Tetrahedral Zn(II)–DOM geometry may be restricted to binding environments containing thiol groups.     

Geochemical fractions and phytoavailability of Zinc in a contaminated calcareous soil affected by biotic and abiotic amendments

Many studies have conducted to determine the best management practice to reduce the mobility and phytoavailability of the trace metals in contaminated soils. In this study, geochemical speciation and phytoavailability of Zn for sunflower were studied after application of nanoparticles (SiO₂ and zeolite, with an application rate of 200 mg kg^?1) and bacteria [Bacillus safensis FO-036b(T) and Pseudomonas fluorescens p.f.169] to a calcareous heavily contaminated soil. Results showed that the biotic and abiotic treatments significantly reduced the Zn concentration in the aboveground to non-toxicity levels compared to the control treatment, and the nanoparticle treatments were more effective than the bacteria and control treatments. The concentration of CaCl₂-extractable Zn in the treated soils was significantly lower than those of the control treatment. The results of sequential extraction showed that the maximum portion of total Zn belonged to the fraction associated with iron and manganese oxides. On the contrary, the minimum percent belonged to the exchangeable and water-soluble Zn (F₁). From the environmental point of view, the fraction associated with iron and manganese oxides is less bioavailable than the F₁ and carbonated fractions. On the basis of plant growth promotion, simultaneous application of the biotic and abiotic treatments significantly increased the aboveground dry biomass yield and also significantly reduced the CaCl₂-extractable form, uptake by aboveground and translocation factor of Zn compared to the control treatment. Therefore, it might be suggested as an efficient strategy to promote the plant growth and reduce the mobile and available forms of toxic metals in calcareous heavily contaminated soils.     

Molecular and serological study on congenital toxoplasmosis in newborn of Shiraz,Southern Iran

Environmental Science and Pollution Research - Toxoplasmosis is a zoonotic disease caused by an obligatory intracellular parasite, Toxoplasma gondii. The congenital form of the disease is a...     

Characterization and antiinflammatory properties of fractionated pyroligneous acid from palm kernel shell

Environmental Science and Pollution Research - Pyroligneous acid (PA) obtained from slow pyrolysis of palm kernel shell (PKS) has high total phenolic contents and exhibits various biological...     

Characterization of Lipopeptides Biosurfactants Produced by a Newly Isolated Strain Bacillus subtilis ZNI5: Potential Environmental Application

Journal of Polymers and the Environment - Aiming the production of lipopeptides biosurfactants (BioS), we isolated a new strain identified as Bacillus subtilis ZNI5 from a hydrocarbon contaminated...     

The dynamic nexus between air transport,technological innovation,FDI, and economic growth: evidence from BRICS-MT countries

Environmental Science and Pollution Research - This study examines the endogenous growth theory for technological innovation and economic growth with the role of foreign direct investment (FDI) and...     

Microplastics in urban waters and its effects on microbial communities: a critical review

Environmental Science and Pollution Research - Microplastic (MP) pollution is one of the emerging threats to the water and terrestrial environment, forcing a new environmental challenge due to the...     

Research trends and emerging physical processing technologies in mitigation of pesticide residues on various food products

Environmental Science and Pollution Research - The application of pesticides enhances food production vastly, and it cannot be prevented; longer fresh produce is contaminated with...     

Orange Juice Processing Waste as a Biopolymer Base for Biodegradable Film Formation Reinforced with Cellulose Nanofiber and Activated with Nettle Essential Oil

Journal of Polymers and the Environment - Concerns about environmental problems have led to the development of biodegradable packaging. Food wastes as a byproduct could be a good source for...