The levels and composition of particulate matter in Ash Meadows National Wildlife Refuge (NWR) that hosts the only population of the endangered Devil’s Hole pupfish (Cyprinodon diabolis) were examined to obtain baseline air quality information. PM₁₀ and PM₂.₅ mass concentrations were measured using continuous monitors over a period of 12 months. In addition, integrated PM₁₀ and PM₂.₅ filter samples were collected and a subset chemically analyzed for elements, ions, elemental carbon, and organic carbon. The average filter-based PM₁₀ (10.9 μg m⁻³) and PM₂.₅ (5.1 μg m⁻³) levels at Ash Meadows NWR are similar to those previously measured at rural and continental background sites in the southwestern USA. Mineral dust accounted for the largest percentage of aerosol mass, with the highest concentrations being measured during fall months of 2009. Elemental and organic carbon levels were generally low, except for August 29, 2009. During this event, transport of wildfire smoke was suggested, by the passage of air masses over wildfires in California, Utah, and Arizona. Ammonium sulfate varied with season, with the highest concentrations in spring and the lowest in fall and winter. Halite (NaCl) quantities were very low, except for the filter samples collected during a windy period on October 4, 2009 indicating the possible contribution of alkaline playa dust upwind of the site. Above average concentrations of crustal calcium compounds, including carbonates and gypsum, were measured in the PM₁₀ sample collected on November 9, 2009 as well as the two preceding months, ascribed to wind-driven dusty conditions prevailing throughout the late summer and fall of 2009.

Poly(vinyl alcohol)/maleic anhydride/acryloyl thioamide monomer (PVA/MA/ATM) nanofiber membranes (NFm) were synthesized by a combination of UV radiation and an electrospinning technique. The PVA/MA/ATM NFm were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), Brunauer–Emmert–Teller (BET) analysis, scanning electron microscopy (SEM), and energy dispersion spectrometry (EDS). These membranes were used for adsorption–desorption of platinum (Pt(IV)) and palladium (Pd(II)) from a fire assay (FA) leaching waste solution, and the effect of process parameters such as pH of solution, contact time, NFm dosage, temperature, and adsorption isotherms and kinetics studies on the recovery of Pt(IV) and Pd(II) from the waste solution were investigated. The adsorption equilibrium data fit better using the Langmuir model than the Freundlich model. Maximum adsorption capacities, Q ₘₐₓ, at 45 °C were found to be 69.93 and 112.36 mg/g for Pt(IV) and Pd(II), respectively. The activation energies (E ₐ) of Pt(IV) and Pd(II) were 27.90 and 20.29 kJ/mol, respectively. The best desorption reagent was a 1.0 M HCl–1.0 M thiourea (TU) solution for both Pd(II) and Pt(IV). Reusability studies showed that the adsorption capacity can remain up to 90 % after five times of usage. This study provides a promising NFm with an effective adsorption property for Pt(IV) and Pd(II) ions.

Methane production by methanogenic microbes under anaerobic condition is affected by the types of fertilizers, which determine carbon availability, used in rice fields. In addition, irrigation management controls oxygen availability in soil. Thus, irrigation management and types of fertilizers are major driving forces for methane emission in rice fields. While these factors affect paddy microbial communities over the course of cultivation, little is known about the effects of fertilizers and irrigation conditions on initial paddy microbial communities. In this study, we investigated the initial impacts of fertilizers and irrigation systems on paddy microbial communities and methane emission. At early stages of rice cultivation (2 weeks after transplanting 15-day-old rice seedlings), a high amount of methane was emitted from rice fertilized with swine manure. In addition, pre-transplantation flooding increased methane emission by 30 %. Although these conditions did not affect the overall paddy soil microbial communities, 126 operational taxonomic units (OTUs) were found to be significantly more abundant in paddy soils fertilized with swine manure. These OTUs included archaeal methanogenic species and bacterial substrate providers for biomethane production. Shared-OTU analysis with swine fecal microbial communities indicated swine manure as the origin of key methane-producing microbes. In conclusion, the applications of swine manure and permanent flooding irrigation introduce active methane producers and enhance methane emission, respectively, and should therefore be avoided.

The textile industry creates environmental problems due to the release of highly polluting effluents containing substances from different stages of dyeing that are resistant to light, water, and various chemicals, and most of them are difficult to decolorize because of its synthetic origin. The biological degradation of dyes is an economical and environmentally friendly alternative. The aim of this work was to use biofilms of basidiomycete fungi isolated from the Peruvian rainforest for the decolorization of synthetic reactive dyes, considering the advantages of these systems which include better contact with the surrounding medium, resistance to chemical and physical stress, and higher metabolic activity. Among several isolates, two were selected for their capacity of rapid decolorization of several dyes and their biofilm-forming ability. These strains were molecularly identified as Trametes polyzona LMB-TM5 and Ceriporia sp. LMB-TM1 and used in biofilm cultivation for the decolorization of six reactive dyes and textile effluents. Azo dyes were moderately decolorized by both strains, but Remazol Brilliant Blue R (anthraquinone) and Synozol Turquoise Blue HF-G (phthalocyanine) were highly decolorized (97 and 80 %, respectively) by T. polyzona LMB-TM5. Degradation products were found by HPLC analysis. Simulated effluents made of a mixture of six dyes were moderately decolorized by both strains, but a real textile effluent was highly (93 %) decolorized by T. polyzona LMB-TM5. In summary, T. polyzona LMB-TM5 was more efficient than Ceriporia sp. LMB-TM1 for the decolorization of textile dyes and effluents at high initial rates enabling the development of in-plant continuous biofilm processes.

The application of biochar as a sustainable material in biofilters to remove volatile compounds from the air provides a lot of advantages in relation to equipment maintenance and efficiency and ensures a zero-emission process. This work has analysed the morphology of biochar produced from birch and pine at different temperatures, its pore structure and changes depending on the type of pollutant and microorganisms used in biofiltrating media. Biochar morphology was investigated by scanning electron microscopy, while biochar pore structure was analysed by mercury intrusion porosimetry and nitrogen absorption at 77 K. Performed tests have shown that the biggest surface area of pores is in the biochar from pine that underwent thermal treatment at 750 °C. It has been determined that the pore volume of pine biochar decreases when acetone, xylene and ammonia pollutants are being removed from air during biofiltration. The biggest changes occurred in the pores with a diameter of 2–20 μm. Meanwhile, after the treatment with the studied volatile compounds, the surface area of pine biochar mesopores with a diameter smaller than 0.05 μm increased.

This work is a synthesis of a 5-year estimation of nitrogen balance at a semi-arid, semi-natural, undisturbed grassland site (Bugac). We measured the N input of atmospheric pollutants by wet and dry deposition of gases and aerosols, while we considered N output as NO and N₂O gases volatilized from soil. Besides measurements of soil fluxes, the denitrification-decomposition (DNDC) ecological model was also used and simulations were compared to and validated against the measured values. The daily flux simulations generally did not match well the measured data for N₂O and NO. In most cases, the mean fluxes were underestimated, though results of the comparison of monthly values suggest that model data, together with observed deposition data, are applicable to estimate the net N balance for grasslands. The calculated yearly N balance (net flux) between atmosphere and surface, without biological fixation and effect of grazing, ranged between −9.4 and −14 kg N ha⁻¹ year⁻¹as the sum of the measured deposition and emission terms, −11 to −15 and 0.9 to 2.9 kg N ha⁻¹ year⁻¹, respectively, between 2006 and 2010. Observed and modeled soil emissions were lower by one order of magnitude than atmospheric deposition. Considering the biological nitrogen fixation and the effect of grazing (effects of both grazed plant and excreta), the net nitrogen balance varies within −6.6 and −11 kg N ha⁻¹ year⁻¹. It seems — taking into account the high uncertainty in calculation due to the effect of grazing — that sources of nitrogen exceed the sinks; the surplus is probably mineralized in the soil.

Lichens absorb water, gases, dissolved substances, and especially pollutants by the entire surface, and they are considered to be the indicators of air quality. In our experiment, a sensitivity of Cladonia arbuscula subsp. mitis and Cladonia furcata lichens with the same photobiont Trebouxia was tested to nitrogen excess through a sensitivity of both the photobiont and mycobiont. Lichen ecophysiological parameters like chlorophyll a fluorescence, chlorophyll a integrity, the content of photosynthetic pigments, ergosterol, soluble proteins, thiobarbituric acid reactive substances, and secondary compounds were measured during two experiments that differed in time of nitrogen exposure. In the short-term experiment, also higher nitrogen concentrations were used to evaluate the dependence of different nitrogen concentrations. In the short-term experiment, lichens were soaked at the different solutions of ammonium nitrate (NH₄NO₃) for describing an immediate effect of range of NH₄NO₃ concentrations. In the long-term experiment, lichens were sprayed with low NH₄NO₃ concentrations for 3 months for evaluating the effect of naturally occurring low nitrogen concentrations. Results showed that lichens responded differently in spite of having the same photobiont. The mycobiont of C. arbuscula subsp. mitis was more sensitive than mycobiont of C. furcata. In higher nitrogen concentrations, the photobiont of C. furcata was more sensitive than C. arbuscula subsp. mitis photobiont. Both lichens exhibited signs of damage; therefore, we conclude that they are sensitive to nitrogen excess, while C. arbuscula subsp. mitis is more sensitive species. The secondary compound content did not change in neither of lichen species. Cladonia sp. response to nitrogen excess depends on length and nitrogen dose exposure.

This study proposes an improved activation for hydrogen peroxide and persulfate using Fe-modified diatomite (MD) to favorably lead the reaction to generate hydroxyl and sulfate radicals to degrade the contaminants phenanthrene and anthracene. Diatomite was modified by impregnating it with a mixture of ferrous (Fe²⁺) and ferric (Fe³⁺) ions in the form of precipitated iron oxides and hydroxides. The raw and synthesized materials were characterized by powder X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size by laser diffraction, chemical microanalysis of the elements by energy-dispersive X-ray, and scanning electron microscopy (SEM). Batch experiments were performed to compare the new activator material (modified diatomite) with traditional methods of activation for these oxidants and to statistically study the optimum ratio between the amount of this material and the concentration of one oxidant to the degradation of the contaminants phenanthrene and anthracene. The characterization results showed that the materials are amorphous and that the Fe ion concentration was 4.78 and 17.65 % for the raw and modified diatomites, respectively. This result shows a significant increase in the amount of iron ions after synthesis. Comparing the traditional activation method with the modified diatomite, the results of batch experiments showed that the synthesized material presents significant catalytic activity for the oxidation of these contaminants, using sodium persulfate and hydrogen peroxide as oxidants. The analysis of the variables results showed that the concentration of the oxidant has higher significance than the amount of the catalyst.

An erythromycin-degrading bacterium was isolated from the activated sludge of a sewage treatment plant (STP). Based on the morphological and physiological characteristics, the isolated strain was identified and named as Pseudomonas sp. ERY-E. In an inorganic salt medium inoculated at 1 % (v/v) of ERY-E strain containing 50 mg/L of erythromycin (ERY), the removal efficiency of ERY as high as 83.7 % was obtained under the optimum conditions with temperature of 30 °C, pH of 7.0, and 10 mg/L of yeast as the external carbon source. Subsequently, the ERY-E strain was used for bioaugmenting a biological aerated filter (BAF) to treat surface water containing low-concentration ERY. The influence of hydraulic retention time (HRT) and air-liquid ratio (A/L) on the performance of BAF was investigated. The average removal efficiencies of ERY and permanganate index (CODMₙ) were about 60.6 and 26.1 % in bioaugmented system (BAF₂) and 26.9 and 26.0 % in unbioaugmented system (BAF₁), respectively, under the optimum conditions with HRT of 4.0 h and A/L of 4:1 at steady state. Due to the stable removal of CODMₙ in BAF₂ as compared with BAF₁, it can be concluded that the introduction of ERY-E strain could collaborate with the indigenous microorganisms to attain a better ERY removal efficiency. As a result, the bioaugmented BAF method can be considered as an alternative technology for the treatment of surface water containing low-concentration emerging pollutants.

The presence of multicomponent nonaqueous phase liquid (NAPL) source zones in the subsurface can significantly complicate remediation efforts, transport predictions, and the development of accurate risk assessments. A series of flow-cell experiments was conducted to investigate the effectiveness of two different enhanced-solubilization agents for the removal of a multicomponent dense nonaqueous phase liquid (DNAPL) source zone from homogeneous porous media. The source zone consisted of an equal 1:1:1 mole mixture of cis-1,2-dichloroethene (DCE), trichloroethene (TCE), and tetrachloroethene (PCE) with NAPL saturation (Sn) targeted between 8 and 14 %. Solutions (5 wt%) of hydroxypropyl-β-cyclodextrin (HPCD) and sodium dodecyl sulfate (SDS) were flushed through the flow-cell system until nearly complete contaminant removal was achieved. Analysis of elution curves indicate that SDS was approximately 10 times more efficient at removing all three components from the system compared to HPCD. Although enhancement factor magnitudes vary for each specific contaminant component and enhanced-solubilization agent, the lowest-solubility contaminant component (i.e., PCE) consistently experienced the greatest relative solubility enhancement during flushing. SDS was generally superior when evaluated on a recovery basis; however, HPCD outperformed SDS for all contaminant components when compared based on moles-contaminant to moles-reagent removal efficiency analysis. Contaminant mass flux reduction analysis showed that enhanced-solubilization flushing (HPCD and SDS) resulted in general inefficient contaminant removal behavior. Raoult’s Law could be used to successfully predict aqueous contaminant concentrations from the multicomponent DNAPL source zone, indicating that dissolution processes were relatively ideal during both HPCD and SDS enhanced-solubilization flushing. These findings suggest that multicomponent NAPL source dissolution and removal depend upon the flushing agent itself and of the solubility and properties of the individual components of the NAPL mixture. The selection of a particular enhanced-flushing agent should be evaluated carefully prior to remediation as the dissolution, removal, and mass flux behavior of each component can vary significantly.