Nitrogen- heterocyclic polycyclic aromatic hydrocarbons (N-PAHs) are ubiquitous constituents of contaminated sites in which their high water solubility and lower k ₒw values imply greater mobility and impacts. Biodegradation is a major route of loss for organic contaminants in soil. In this study, microbial degradation was investigated in soil artificially contaminated with N-PAHs and monitored for over 200 days. The results showed that all the aromatic chemicals exhibited loss with increasing incubation time; however, only 0.05 ± 0.04 mg kg day⁻¹ loss was observed for N-PAHs at 10 mg kg⁻¹ amendments over the first 30 days incubation, with the exception of 4,7-phenanthroline which recorded 0.19 ± 0.03 mg kg day⁻¹. The study showed that soil microflora have the potential to degrade N-PAHs since all of the aromatics recorded chemical losses under aerobic condition. However, degradation rates varied between chemicals and this was attributed to N-atom position and/or number of N-substituents. Further, relatively little or no biodegradation was observed in B[h]Q amended soils with increasing concentration; indicating that B[h]Q is more resistance to biodegradation in soil.

Sorption of four ionizable organic amines, n-hexylamine, trimethylamine, 1-naphthylamine, and phenylamine, on a soil sample were measured, and their effects on the sorption of phenanthrene (PHE) to the same adsorbent were studied. The aim of this study was to better clarify sorption mechanisms of chemicals with different polarity and ionization characteristics in a single-solute system and in a polar/nonpolar binary system. In the single system, cationic organic amines exhibited greater sorption than those in a neutral form, and the sorption increased with hydrophobicity for amines with the same form. In the binary system, the sorption of PHE was promoted in the presence of n-hexylamine and the solid-water distribution coefficient (K d) increased with increasing amine concentrations. This may be explained by the elevated amount of hydrophobic organic sites provided by the head-on adsorption of cationic n-hexylamine to the negatively charged sorbent surface, which are probably more favorable for the sorption of PHE compared with natural organic matters. Contrarily, the neutral amine, 1-naphthylamine, might compete with PHE for the mutually available hydrophobic sites and hence inhibited PHE sorption. On the other hand, both trimethylamine and phenylamine had little effects on PHE sorption due to their relatively high solubility and weak hydrophobicity. Therefore, either in single or binary system, both the form and the solubility/hydrophobicity of the compound play important roles in the sorption of ionizable organic amines and their effects on the sorption of nonpolar co-solute.

Arbuscular mycorrhizal fungi (AMF) can alter the dynamics of soluble nitrogen in paddy field soils by promoting nitrogen assimilation by rice. However, it is unknown whether this affects N₂O emissions from rice paddies. This study was designed to assess the effects of AMF on N₂O emissions by analyzing the relationships between AMF and the parameters affecting N₂O emissions. Path analysis was used to quantitatively partition the direct and indirect effects of different parameters on N₂O emissions. Results showed that N₂O emissions were controlled by environmental pathways (transpiration, evaporation, and precipitation affecting soil water content) and biotic pathways (soluble nitrogen assimilation by the rice, which varies according to rice biomass). Under different water conditions, the contributions of the two pathways to N₂O emissions varied strongly. During the flooding stage, the environmental pathways were dominant, but inoculation with AMF promoted the contribution of the biotic pathway to the reduction of N₂O emissions. During the draining stage, the environmental pathways were dominant in the non-inoculated treatment, but inoculation made the biotic pathways dominant by increasing the biomass of rice. During the growing stage, N₂O emissions from inoculated soil (17.9–492.9 μg N₂O-N m⁻² h⁻¹) were significantly lower than those in non-inoculated soil (22.1–553.1 μg N₂O-N m⁻² h⁻¹; p < 0.05). Consequently, inoculating with AMF has the potential for mitigating N₂O emissions from rice paddies.

The selected strains of microscopic fungi, Haematonectria haematococca (BwIII43, K37) and Trichoderma harzianum (BsIII33), decolorized the following monoathraquinone dyes with different efficiency: 0.03 % Alizarin Blue Black B, 0.01 % Carminic Acid, 0.01 % Poly R-478, and 0.2 % post-industrial lignin. The most effective was the removal of 0.03 % Alizarin Blue Black B (50–60 %) and 0.01 % Carminic Acid (55–85 %). The principal component analysis (PCA) method was applied to determine the main enzyme responsible for the biodecolorization process of the dye substrates and indicated that horseradish-type (HRP-like), lignin (LiP), and manganese-dependent (MnP) peroxidases were responsible for the decolorization of anthraquinone dyes by the strains tested. The participation of particular enzymes in the decolorization of monoanthraquinone dyes ranged from 44.48 to 51.70 % for 0.01 % Carminic Acid and from 38.46 to 61.12 % for Poly R-478. The highest precipitation in decolorization of these dyes showed HRP-like peroxidase, respectively, 54–74 and 70–95 %. The degree of decolorization of 0.2 % post-industrial lignin by the selected strains of H. haematococca and T. harzianum amounted to 58.20, 61.38, and 65.13 %, respectively. The rate of 0.2 % post-industrial lignin decolorization was conditioned by the activity of HRP-like (71–90 %) and LiP (87–94 %) peroxidases.

P(Acrylamide) (p(AAm)) cryogel with superporous structure was synthesized by employing a cryopolymerization technique under freezing conditions. The prepared cryogels were modified by amidoximation to generate new functional groups as amid-p(AAm) cryogel, that binds metal ions, and the metal nanoparticles of those ions were prepared via in situ reduction method. The prepared amid-p(AAm)-M cryogel composites (M: Cu, Ni, and Co) were used as superporous reactor for the catalytic reduction of toxic phenol compounds 2- and 4-nitrophenol (2- and 4-NP) and some dyes methylene blue (MB) and Eosin Y (EY). P(AAm) cryogels and their metal composites were characterized by using FT-IR analysis, SEM images, and AAS measurements. The impact of porosity, the types and amount of metal catalyst, temperature of reaction medium, and so on were investigated for toxic 2-NP reduction by amid-p(AAm)-M cryogel composites. Very high total turnover frequencies (TOF) and low activation energy (Ea) values of 2.46 (mole 2-NP) (mole Cu. min)⁻¹and 20.2 kJmol⁻¹were obtained for catalytic reduction of 2-NP compound catalyzed by amid-p(AAm)-Cu cryogel composites. Consequently, superporous p(AAm) cryogel is the perfect support material for metal nanoparticle preparation and use in catalytic reduction reactions.

This paper presents the results of a study on mercury distribution in urban wells from the town of Almadén (central Spain), a site that not only hosted the world’s largest mercury mine but also a large roasting plant for cinnabar (HgS). The study includes data on Hg contents in the underground waters and also quality and physical-chemical parameters such as pH, conductivity, oxidation-reduction potential (ORP), dissolved oxygen, and water temperature from 27 wells and 2 monitoring drill holes. An important proportion of the wells (16 %) display Hg concentrations above the European Union Commission (EUC) and Spanish threshold (at 1 μg L⁻¹) and only 10 % exceeded the US EPA recommendation (at 2 μg L⁻¹). As expected, the highest concentrations of dissolved and total Hg are found in wells near to the mine. Hydrochemical water types depend on geogenic and anthropogenic factors, for example, higher mercury concentrations are linked to water-rock interactions (e.g., oxidation, leaching) in sectors where soluble mercury compounds have formed. Hg concentrations show a decrease from 2013 to 2015, a fact that may be due to the encapsulation of the main calcines waste dump or to dilution effects related to strong rainfall events previous to the sampling survey.

Phytoremediation employs plants to sequester, degrade, and transform contaminants. This remediation technology depends on sufficient plant growth, often not achievable with high contaminant concentrations. One way to improve plant growth on impacted soils is by using plant growth-promoting rhizobacteria (PGPR). PGPR are naturally occurring soil microbes that stimulate plant growth through variety of means. We examined what changes in gene expression occurred in a grass species Secale cereale treated with PGPR, Pseudomonas putida PGPR (UW4), grown in petroleum hydrocarbon (PHC) impacted soil. UW4 promoted plant growth on the PHC impacted soil. Using differential display polymerase chain reaction (ddPCR), six genes were identified based on their altered expression as an effect of PHC exposure and plant PGPR treatment. The changes in levels of expression of selected genes were measured using quantitative PCR (qPCR). There was upregulation of all six genes examined, two of which were statistically significant. In roots, two genes were upregulated significantly and one gene appeared to be downregulated.

Changes in crude oil production and distribution have increased the incidence of oil spills throughout the world. Oil spills often cause destructive effects on aquatic and land ecosystems. The oil spill cleanup and recovery techniques are challenging and usually involve complex mechanical, chemical, and biological methods. Usually, mechanical removal of free oil is utilized as an effective strategy for cleanup in aquatic and terrestrial environments; however, they are expensive and need specialist personnel and equipment. The other commonly used method is the application of chemical materials such as dispersants, cleaners, demulsifiers, biosurfactants, and soil oxidizers. Nevertheless, these reagents can have potential harmful environmental impacts, which may limit their application. As an alternative, bioremediation can offer reduced environment risk; however, the limitations of microbial activity in the soil can make this option unsuitable. One area of bioremediation is phytoremediation, which offers potential for restoring large areas of contaminated ground. Plants are able to remove pollutants through processes such as biodegradation, phytovolatilization, accumulation, and metabolic transformation. This review presents the fate of crude oil spills in aquatic and land ecosystems and their environmental effects. Furthermore, the paper focuses on crude oil phytoremediation and its applications in polluted ecosystems.

The removal of fluoride from water by an aluminum-modified hematite and a zeolitic tuff using column adsorption techniques, as well as the effects of temperature, were investigated. Column experiments were carried out using aqueous solutions and drinking water with different bed depths. The dynamics of the adsorption process were fitted to Adams–Bohart, Thomas and bed depth service time (BDST) models. The Thomas model was found suitable for the description of breakthrough curve at all experimental conditions, while Adams–Bohart model was only useful for an initial part of dynamic behavior of the removal of fluoride from water by aluminum-modified hematite and zeolitic tuff columns. The highest uptake capacities (3.24 and 2.37 mg/g for the modified zeolitic tuff and hematite respectively) were obtained with a 4-cm bed depth column, an inlet 10 mg/L fluoride solution, and a flow rate of 1 mL/min, but the adsorption capacities decreased when drinking water were used. Experimental data were good fitted to both models, and the parameters of the processes calculated indicated that these materials are suitable for removal of fluoride from water in column systems. Thermodynamic parameters (ΔS, ΔG, and ΔH) were calculated for the aluminum-modified hematite and zeolitic tuff from the sorption data at temperatures between 287 and 333 K, indicating spontaneous and thermodynamically favorable adsorption and suggest that the sorption of fluoride ions by both adsorbents is an endothermic process and the mechanism is physical sorption.

This paper analyzes the implications for children’s health of shortcomings in the methods and results of a study of lead in the environment, “Quantity of Lead Released to the Environment in New Jersey in the Form of Motor Vehicle Wheel Weights,” by the New Jersey Department of Environmental Protection (Aucott and Caldarelli, Water, Air, & Soil Pollution, 223, 1743–1752, 2012). The study significantly understates the amount of lead deposited in New Jersey streets as 12 metric tons per year and incorrectly concludes that only 40 kg per year of the lead from wheel weights is abraded into small particles. The 2012 New Jersey Department of Environmental Protection (NJDEP) study misleads regulators and the public into believing that little toxic particulate lead from abraded wheel weights occurs on the streets of New Jersey and by implication that little occurs elsewhere in the United States, thus minimizing the potential health risk that lead wheel weights may have to our nation’s children and indeed all of us.