To investigate the differential contribution of extracellular polymeric substances (EPS) to polycyclic aromatic hydrocarbon (PAH) degradation by fungi and bacteria, the PAH-degrading ability and characteristics of EPS from the bacterium Mycobacterium gilvum SN12 and the fungus Mucor mucedo were compared. The fungus degraded 11% more pyrene and 21% more benzo[a]pyrene (B[a]P) than the bacterium. The biodegradation of pyrene and B[a]P increased after EPS were introduced into the PAH degradation solution, and 5.0% more pyrene and 4.5% more B[a]P were achieved for the added EPS from the fungal compared with the bacterial isolate. The comparison of two EPS indicated that the amount of protein and carbohydrate in EPS from the fungus was greater than that from the bacterium and was especially enriched for tryptophan, which is positively related to the increase of PAH biodegradation by fungal EPS. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) further revealed that higher molecular weight (HMW) of proteins over 200 kDa only existed in EPS from the fungus, and the polymorphism of proteins in EPS from the fungus was more abundant than that from the bacterium. The HMW proteins with stronger hydrophobicity in the fungal EPS also enabled the fungus to absorb more PAH than the bacterium. The results demonstrated that the pronounced differences in the characteristics of EPS from the fungal and the bacterial sources are responsible for the differential effects on PAH biodegradation.

Two species of Pb-adapted shrubs, Alyssum montanum and Daphne jasminea, were evaluated in vitro for their tolerance to elevated concentrations of cadmium. Shoot cultures were treated with 0.5, 2.5, and 5.0 μM CdCl₂ for 16 weeks and analyzed for their organogenic response, biomass accretion, pigment content, and macronutrient status. Cadmium accumulation and its root-to-shoot translocation were also determined. In both species, rooted microplantlets, suitable for acclimatization, were obtained in the presence of Cd applied as selection agent. In A. montanum, low and moderate dose of Cd stimulated multiplication, rooting, and biomass production. Growth tolerance index (GTI) in Cd-treated shoots ranged from 120 to 215%, while in the roots 51–202%. In turn, in Cd-treated D. jasminea proliferation and rooting were inhibited, and GTI for shoots decreased with increasing doses of Cd. However, roots exposed to Cd had higher biomass accretion. Both species accumulated Cd in developed organs, and its content increased with increasing CdCl₂ dose. Interestingly, D. jasminea accumulated higher amounts of Cd in the roots than A. montanum and immobilized this metal in the root system. On the contrary, A. montanum translocated some part of accumulated Cd to the shoots, but with low efficiency. In the presence of Cd, A. montanum maintained macronutrient homeostasis and synthesized higher amounts of phytosynthetic pigments in the shoots. D. jasminea accumulated root biomass, immobilized Cd, and restricted its translocation at the expense of nutrient balance. Considering remediation potential, A. montanum could be exploited in phytoextraction, while D. jasminea in phytostabilization of polluted substrate.

Nanoscale zero valent iron (NZVI) was synthesized by the reduction of natural limonite under hydrogen conditions. The adsorption performance of the as-prepared NZVI on phosphate was evaluated through batch and column experiments. The removal of phosphate (PO₄³⁻) significantly decreased with an increase of pH from 2.0 to 11, whereas a remarkable increase of PO₄³⁻ removal was observed in the presence of SO₄²⁻ and S₂O₃²⁻. In addition, Cl⁻ and NO₃⁻ also improved phosphate removal at concentrations of more than 0.2 mmol/L. Kinetic studies indicated that the removal process of PO₄³⁻ on NZVI can be easily followed with the pseudo-second-order kinetic model. The removal of phosphate from the oxic system was significantly higher than that of the anoxic system, which was attributed to the formation of the secondary phase by the further oxidization of Fe²⁺. The adsorption capacity of the as-prepared NZVI of the oxic system was 16 mg/g, and the pH was 6.3. The column experiments further demonstrated that the as-prepared NZVI presented a high removal capacity for PO₄³⁻-P. These findings indicated that the as-prepared NZVI displayed an excellent ability to remove phosphate from aqueous solutions.

The aim of this work was to analyse the response of Rosa rubiginosa to salinity induced by different concentrations of sodium chloride and calcium chloride (0, 25, 50, 100, 150 and 200 mM). Besides salt accumulation and pH changes, other parameters were investigated including photosynthetic activity, leaf water content, the dynamics of necrosis and chlorosis appearance and leaf drying. The study was complemented with microscopic analysis of changes in leaf anatomy. R. rubiginosa was more sensitive to the salinity induced by calcium chloride than by sodium chloride. Plant response to salinity differed depending of the salt concentration. These differences were manifested by higher dynamics of necrosis and chlorosis appearance and leaf drying. CaCl₂ showed greater inhibition of the photosynthetic apparatus and photosynthetic activity. Treatment with CaCl₂ caused more visible deformation of palisade cells, reduction in their density and overall reduction in leaf thickness. The study demonstrated higher accumulation of CaCl₂ in the soil, and thus greater limitations in water availability resulting in reduced leaf water content and quicker drying of leaves as compared with NaCl-treated plants.

Water contamination has reached an alarming state due to industrialization and urbanization and has become a worldwide issue. Dyes contaminate water and are addressed extensively by researchers. Various technologies and materials have been developed for the treatment of contaminated water. Among them, adsorption has attracted great attention due to its ease and cost-effective nature. In recent years, graphene-based composites have shown great potential for the removal of contaminants from water. The literature reveals the usefulness of composites of graphene with metal oxides, carbon derivatives, metal hybrids and polymers for the removal of organic dyes from contaminated water. In this review, efforts have been made to compile the studies on the removal of cationic and anionic dyes from water using graphene-based composites.

The Pantanal is an extensive flooded plain, rich in biodiversity and considered a Biosphere Reserve and World Heritage Site. It has great complexity and can be divided into regions due to its each distinct characteristic. Nhecolândia is a very peculiar region because it is made up of thousands of freshwater and brackish ponds. The study objective was to evaluate the physical-chemical parameters of the Nhecolândia ponds and to analyze the vegetation indexes generated from UAV aerial photographs in order to identify what best distinguishes freshwater and brackish ponds and to differentiate study area features. The in-field and image data collection were performed on June 20, 2015. The aerial photographs were processed to obtain mosaic which served as a vegetation index basis. The indexes and wavelengths in the visible region analyses were performed for each of the area’s ponds. It was observed that bays and salines have a differentiated spectral behavior. The excess green and normalized excess green vegetation indexes presented results enough to separate freshwater from brackish ponds, plus to differentiate many study area features.

We present a study on the radioactivity of selected Croatian agricultural soils that vary considerably with respect to geological background; physical, chemical, and biological characteristics; soil type; land use; and soil management. Our investigation is focused on the main naturally occurring radionuclides (⁴⁰K, ²³⁸U, ²²⁶Ra, ²³²Th, ²³⁵U) and ¹³⁷Cs as the most threatening long-lived anthropogenic radionuclide. We find that the radioactivity level is not influenced by the application of different soil amendments, at least in moderate quantities, and that no effect of soil management can be detected as well. In contrast, geological and location-specific properties influence radionuclide content in soil, especially regarding the naturally occurring ones. Moreover, physical and chemical soil properties such as texture and soil adsorption complex, respectively, seem to be the main factors regarding fixation of ¹³⁷Cs in soil. Calculated dose rates for external exposure to the gamma radiation originating from soil have been found to be generally low, except for two locations where they are higher but not at a level that would lead to health problems for workers on the field.

The contamination of drinking water with arsenic has been a problem in a lot of countries around the world because of its toxicological and carcinogenic effects on human health. Porous materials modified with Fe₃O₄ nanoparticles (Fe₃O₄ NPs) represent convenient removers for that contaminant. A co-precipitation method of Fe(III) and Fe(II) in alkaline media was applied to obtain Fe₃O₄ NPs. In a first stage, single nanoparticles were synthesized and stabilized with carboxylic acids. A characterization with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, and X-ray diffraction (XRD) confirms a magnetite-type structure. Moreover, transmission electron microscopy (TEM) and calculations from XRD data using Scherrer’s equation indicate an average particle size of 13 nm and an average crystallite size of 10 nm, both independent of the stabilizer used. Then, the co-precipitation method studied was applied to modify kaolin, bentonite, diatomite, and silica and thus prepare magnetic composites having support-magnetite weight ratios of 2:1. Among them, silica-modified material presented the best hydraulic characteristics, an important aspect for large-scale applications such as removal under gravity. This composite has the capacity to remove up to 80 and 70% for initial concentrations of 25 and 50 μg/L, respectively, representing a convenient remover for processes developed in subsequent stages or in continuous flow.

This study aimed to quantify the water balance components at a grassland and a forest site representative of the Atlantic Forest biome in southern Brazil using drainage lysimeters. Since it was not possible to place mature trees on the forest lysimeter, it was planted with young trees and understory vegetation. Data from this lysimeter and computations with the water balance and the Penman-Monteith equation were then used to assess the values of the water balance components for the mature forest.Total precipitation during the study period was 2308 mm. In the forest environment, 46% thereof was intercepted by the canopy from where it later evaporated. Hence, much less rain reached the ground than under grassland. Runoff from both sites was <1% of precipitation and therefore not a significant factor in the water balance. Cumulative drainage amounted to 1136 mm from grassland: from the mature forest, it was estimated to be 389 mm. There were two reasons for this low value under forest: Interception prevented a lot of water from reaching the ground, and the actual evapotranspiration from the mature forest was much higher than from grassland (1231 mm compared to 1964 mm).

Carbon nanotubes (CNTs) synthesized by the catalytic decomposition of methane were used as the support for magnetic Fenton and photo-Fenton catalysts to treat real wastewater contaminated with dyes and Escherichia coli. The effect of methane flow, the use of diluent (N₂), and the reaction time in the production of CNTs were studied. An increase in the production of CNTs with increased CH₄ flow and a decrease over the reaction time were recorded. Catalysts with 1, 3, and 5% w/w Fe were obtained and characterized by several spectroscopic and microscopic techniques. Multi-walled CNTs and bamboo-like carbon nanofibers with average diameters of 44.0 nm and average lengths of 237.0 nm were obtained. The catalysts had Fe ₓ O y (oxide species) crystallite sizes between 10 and 18 nm and soft ferromagnetic properties. A factorial 3³ design was used for selecting variables for the catalytic tests, wherein the concentration of H₂O₂, the catalyst mass, and the percentage of iron were evaluated. Subsequently, kinetic experiments were performed. The photo-Fenton process (5% Fe, 200 mg, and 0.4 M H₂O₂) showed the best results in terms of total organic carbon (TOC) abatement, discoloration, and E. coli inactivation without leaching of Fe. Graphical Abstract ᅟ