Hundreds of millions of people are at risk from drinking arsenic (As)-contaminated groundwater in the world, making As removal from aquatic systems of utmost importance. However, characteristics of As removal by bacteria-induced ferrihydrite and coupled with redox processes are still not clear. Two-line ferrihydrite was formed in the presence of aerobic Fe(II)-oxidizing bacterium, Pseudomonas sp. strain GE-1. Arsenic co-precipitation with and adsorption onto ferrihydrite induced by Pseudomonas sp. strain GE-1 and redox processes of As were investigated. Results demonstrated that co-precipitation performed better in As(V) removal than As(III) removal, while adsorption showed higher capacity for As(III) removal. X-ray absorption near-edge spectroscopy (XANES) indicated that As(III) oxidation occurred in solid phases during co-precipitation and adsorption. Detection of As species in solution showed that As(V) was reduced to As(III) during co-precipitation, although no As(V) reduction occurred during adsorption. Arsenic immobilization by Pseudomonas sp. strain GE-1-induced ferrihydrite in the presence of the strains may be applied as an alternative remediation strategy.

Calcium alginate beads entrapping a mixture of Fe(0) and nanosized magnetite (NMT) were prepared and evaluated for their capability to reduce nitrate in groundwater. Microscopic and spectroscopic analyses of the beads revealed that clusters of Fe(0)/NMT were entirely embedded in alginate polymer matrix containing a large number of carboxylic and hydroxyl functional groups. The extent of nitrate reduction increased with increasing content of Fe(0) and NMT in the beads, but there was a critical NMT mass limit relative to Fe(0) mass where no further increase in nitrate reduction occurred. The beads showed slower nitrate reduction kinetics than bare Fe(0)/NMT but had comparable capacity in overall nitrate removal. Nitrate reduction increased proportionally with an increase in bead dosage to give a maximum removal of 94.5 % at 37.5 g L⁻¹ in 48 h. Nitrate reduction with 50 g L⁻¹ beads achieved completion of two reduction cycles in 72 h to reduce 2.19 mM nitrate to less than 0.71 mM (10 mg-N L⁻¹) in each cycle. The overall results demonstrated that the beads developed in this study have a potential utility in remediation of nitrate in groundwater.

This work describes the experimental determination of the major degradation and sorption parameters of polycyclic aromatic hydrocarbons (PAHs) in a sensitive marine environment, the Northern Adriatic Sea (Mediterranean Sea). The persistence and sorption of complex PAH mixtures were analysed in the laboratory in conditions mimicking open-sea and coastal sediments, which differ in grain size and organic carbon content and are characterized by different oceanographic conditions including abiotic influences. The study investigated how sediment type and texture and salinity, temperature and solar irradiation conditions affect the partitioning of low molecular weight (LMW) and high molecular weight (HMW) PAHs into aqueous and solid phase, which critically influence their behaviour. With regard to the change from offshore to coastal conditions, HMW PAHs were found to be more sensitive to the increased salinity (from 21 to < 37 parts per thousand), whereas LMW PHAs were more sensitive to the temperature increase (from 11 to 22 °C). HMW PAHs were more affected by sediment type changes in terms of distribution coefficient (K d). Since the physicochemical properties of organic pollutants affect their distribution, transport, bioavailability and toxicity, analysing the accumulation and persistence of dissolved pollutants can provide useful information for environmental risk assessment and management.

Bacteria that harbor the mer operon in their genome are able to enzymatically reduce mercury (II) to the volatile form of mercury Hg (0). Detoxification of contaminated waste by using these bacteria may be an alternative to conventional methods for mercury removal. Residual glycerol from the biodiesel industry can be used as a carbon source to accelerate the process. This work shows for the first time the feasibility of using residual glycerol as a carbon source for Hg removal by bacteria prospected from contaminated environments. Eight bacterial isolates were able to remove mercury and degrade glycerol in mineral medium and residual glycerol. Mercury removal was monitored by atomic absorption spectroscopy and glycerol degradation by high performance liquid chromatography. The best results of mercury removal and glycerol degradation were obtained using isolates of Serratia marcescens M25C (85 and 100 %), Klebsiella pneumoniae PLB (90 and 100 %), Klebsiella oxytoca (90 and 100 %), and Arthrobacter sp. U3 (80 and 75 %), with addition of 0.5 g L⁻¹ yeast extract. The Arthrobacter sp. U3 isolate is common in soils and has proven to be a promising candidate for environment applications due to its low pathogenicity and higher Hg removal and glycerol degradation rates.

Fluorene belongs to the polycyclic aromatic hydrocarbons (PAHs) which are potentially carcinogenic or mutagenic. However, very few studies on biodegradation of three-ring fluorene were investigated as compared to other three-ring PAHs such as phenanthrene and anthracene. The aim of this work is to evaluate fluorene degradation by fungal strain isolated from the decayed wood in tropical rain forest, Malaysia, and examine the effectiveness of the strain for degrading fluorene in liquid culture supplemented with the nonionic surfactants. Detailed taxonomic studies identified the organisms as Pestalotiopsis species and designated as strain Pestalotiopsis sp. W15. In this study, fluorene was totally degraded by Pestalotiopsis sp. W15 after incubation for 23 days. Various analytical studies confirmed the biotransformation of fluorene by detection of two metabolites in the treated medium: indanone (R f 0.45; λ ₘₐₓ 240 and 290 nm; t R 7.1 min and m/z 132) and salicylic acid (λ ₘₐₓ 205, 235, 290 nm; t R 9.4 min and m/z 382). Based on these products, a probable pathway has been proposed for the degradation of fluorene by Pestalotiopsis sp. W15. None of the intermediates were identified as dead-end metabolites.

The diversity and spatial structure of soil fungi (SF) and arbuscular mycorrhizal fungi (AMF) communities in the southern taiga forest litter were studied in sites with two contrasting contamination levels with copper smelter emissions. The operational taxonomic unit richness and evenness in the communities of both target groups decreased under contamination. The community structure of contaminated and control areas differed for SF, whereas they were similar for AMF. According to spatial structure analysis results on a scale of tens of meters, a gradual change of composition with distance was revealed for the SF community within 30-m intervals in the control sites. No spatial autocorrelation was found for AMF in the control sites. However, pronounced patchiness was characteristic of both SF and AMF communities within 10 m of contaminated sites. In the contaminated area, no specific spatial structure determinants of the studied communities was found among environmental factors such as water content, heavy metal concentrations in the forest litter, sample plot localization relative to canopy density, and herb vegetation diversity and abundance. However, in the control sites, AMF richness depended on herb abundance and litter chemistry.

Accumulations of mass loads of selected chemicals in roadside snowbanks were studied at five sites with various traffic densities in the city of Trondheim (Norway) by collecting snow samples throughout the winter period and analyzing them for 13 water quality constituents: pH, electrical conductivity (EC), alkalinity, Cl, Na, total suspended solids (TSS), Cd, Cr, Cu. Ni, Pb, W, and Zn. The resulting dataset was then supplemented by similar data collected earlier in the city of Luleå (Sweden). Regression analyses for individual sites indicated linear trends in unit-area constituent accumulations with time (0.65 < R ² < 0.95) and supported the assumption of linearity in further analyses. Principal component analysis (PCA) of the combined Luleå/Trondheim data revealed cause-effect relationships between the chemical mass loadings (TSS and trace metals) and three predictors: snow age (snow residence time (SRT)), traffic density (annual average density of traffic (AADT), and cumulative traffic volume (CTV = SRT × AADT). Cl and Na loads, originating from road salt applications in Trondheim only, did not display this trend. Two types of parsimonious models for predicting trace metal accumulations in winter-long roadside snowbanks were developed: (a) a linear regression model using CTV as a single predictor and predicting metal accumulations with a moderate certainty (0.37 < R ² < 0.66) and (b) multiple regression models using SRT, AADT, and snow water equivalent (SWE) as predictors. The latter models indicated good correlations between the mass loads and the predictors (0.64 < R ² < 0.77) and produced slightly better prediction accuracies (0.44 < R ² < 0.67) than the simpler model.

Integrating vegetation into architecture has become widely recognized as a multi-beneficial practice in architecture and engineering design to combat an array of environmental issues. Urban areas have microclimates that are different than the climates of their surrounding rural areas. Patterns in these differences over the years have shown that urban microclimates tend to be significantly warmer in comparison. This phenomenon is now recognized as the urban “heat island” effect. While the associated consequences of this urban heating are far reaching, excess energy expenditure, air pollution emissions, and threats to human health are among the most critical for evaluation. The integration of vegetative green space in urban planning, coupled with highly reflective materials in place of conventional paved surfaces on roads and rooftops have proven to be effective methods of urban heat island mitigation. While as separate entities these methods are effective, innovative technology has brought forth greening roofs which allows vegetation to compensate where other roof-cooling strategies fall short. Substantially, vertical greenery systems compensate where greening roofs fall short. This paper explores both integrated vegetation as an optimal mitigation strategy for urban heat islands and vertical plant walls as an optimal design.

Effects of pH, As species, and Fe/Mn minerals on the fractions of adsorbed As in aquifer sediments were evaluated. Kinetic data showed that As adsorption was controlled by diffusion through the external film. Isothermal data of both As(III) and As(V) fitted the Langmuir isotherm well, revealing a monolayer adsorption process. Sequential extraction demonstrated that water-soluble As and non-specifically sorbed As were the major fractions of adsorbed As. Assessing the relationship between the Freundlich K F and the increases in the amounts of As fractions showed that the pH played a key role in weakly adsorbed As, especially water-soluble As. Although inorganic As species converted each other during the adsorption processes, more non-specifically sorbed As was adsorbed in As(V)-treated sediment than in As(III)-treated sediment, showing that the electrostatic selectivity controlled the non-specific adsorption. Additionally, specifically sorbed As and As associated with the amorphous phases were predominated by Fe/Mn minerals, especially Fe(III) (hydr)oxides. These results suggested that pH, As species, and Fe/Mn minerals would regulate the As fractions in aquifer sediments, and therefore control As cycling in aquifer systems.

The presence of pharmaceuticals and personal care products (PPCPs) as trace pollutants in natural surface water bodies, ground water and drinking water has recently led to some concern. Advanced oxidation processes (AOPs), which utilize free radical reactions to degrade chemical contaminates, are an alternative to traditional water treatment. Anti-inflammatory drug balsalazide (as model compounds) besides actual wastewater samples were UV photodegraded using suspended titanium silicon oxide (TiSiO₄) or UV/H₂O₂/O₂ systems. The photodegradation was favourable in the pH 8–12.8 range. The effect of various parameters such as photocatalyst amount, balsalazide (BSZ) concentration, pH of aqueous solution, irradiation time, addition of H₂O₂ and temperature on photocatalytic oxidation was investigated. The kinetics of the photocatalytic oxidation of BSZ in aqueous TiSiO₄ suspensions was investigated as a function of catalyst loading (2–12 mg/L) and the concentration of BSZ (0.01–0.05 mg/mL) at pH 11.5. The optimum conditions for the degradation of the BSZ have been found as 0.045 mg/mL drug concentration, pH 11.5 and 0.1 g/L catalyst dose. The results indicated that the photocatalytic degradation of BSZ was well described by pseudo-first-order kinetics according to the Langmuir–Hinshelwood model. The effect of temperature on the efficiency of photodegradation of BSZ was also studied in the range 278–298 K. The activation energy was calculated according to Arrhenius plot and was found equal to 24 ± 1 kJ mol⁻¹ for TiSiO₄. Decolourization and mineralization of BSZ in the absence of light and/or catalyst were performed to demonstrate that the presence of light and catalyst is essential for the decolourization of this BSZ. This work adds to the global discussion on the role of the advanced oxidation processes in water treatment.