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.

A coupling technique is developed to predict the behavior of a buoyant river plume in a lake. The model incorporates a 3D hydrodynamic model (POMGL) and a 3D particle tracking model (Partic3D) for the far-field transport computations. The source conditions for the particle tracking model are obtained from a near-field model derived from the characteristics of the plume analyzed from extensive field studies on the Grand River plume, Lake Michigan. The empirical near-field model was developed to predict the geometry of the plume, dilution, and centerline trajectory near the river mouth, and to provide the concentration and location of the particles to be released in the far field. The coupled empirical-numerical model shows improved predictions in the near field versus the single numerical model. The present results strongly advocate the use of model combinations in order to improve coastal diffusion and transport processes. The primary application of the technique is in recreational water early-warning and forecasting systems that will estimate the immediate and short-term risk of exceeding pathogen indicator concentration criteria in lakes and coastal areas.

Eutrophication related to excess phosphorus (P) loadings continues to be an important issue for watersheds in North Carolina and other regions. Identifying the contributing sources of P in nutrient-sensitive waters is important for improving water quality. Prior studies have indicated that onsite wastewater treatment systems (OWS) can be a contributing source of P to surface waters, but more information is needed regarding their contribution relative to other wastewater treatment technologies. The goal of this study was to determine if P concentrations in groundwater and surface water were significantly different in a coastal plain watershed served by OWS in comparison to a watershed served by a municipal sewer system (MWS). Groundwater P concentrations were monitored at ten residential sites (five5 OWS and five MWS) once during each season (four times), and stream P concentrations and watershed exports were monitored monthly for 1 year (August 2011–August 2012). Groundwater in the OWS watershed had higher P concentrations than the MWS watershed. Stream P concentrations and P exports were also elevated in the OWS watersheds. However, the OWS were more efficient at reducing P prior to surface water discharge than the wastewater treatment plant that served the MWS watershed. The site-scale and watershed-scale P treatment efficiencies of OWS were between 73 and 99 %, whereas P treatment efficiency for the wastewater treatment plant was 54 %. While the OWS were efficient at reducing P concentrations and loads, OWS were still significant sources of P exports from the studied watershed. Potential contributions of P from OWS should be included in watershed nutrient management strategies along with other known sources such as agriculture and urban runoff if the strategies are to be considered comprehensive.

Lignin is the major polluting and colouring constituent present in pulp and paper mill effluent. To degrade lignin and its derivatives, bacterial enzymes can play an important role due to stability at extreme environmental conditions. This study explored the degradation of pulp and paper mill effluent by a rod-shaped Gram-positive bacterial strain RJH-1, isolated from sludge, based on its efficiency to reduce COD, colour, AOX and lignin content. This bacterial isolate was able to grow in nitrogen-free Jensen medium. Further, RJH-1 was identified as Brevibacillus agri strain after 16 s rRNA gene sequencing. Degradation potential of this isolated bacterial strain was evaluated by batch and semi-continuous reactor study. In batch study, the isolate reduced 69 % COD, 47 % colour, 37 % lignin and 39 % AOX after 5 days whereas in control flask, 40 % COD, 26 % colour, 19 % lignin and 22 % AOX reduction was observed by the indigenous bacteria present in wastewater. During semi-continuous reactor study, it reduced 62 % COD, 37 % colour, 30 % lignin and 40 % AOX of effluent at a retention time of only 32 h whereas the reduction in control reactor was 36 % COD, 21 % colour, 18 % lignin and 29 % AOX. This study confirmed that the B. agri has the potential to degrade the lignin and reduce the colour and COD of the pulp and paper mill waste water.

The aim of this study was to describe the mechanisms that native Bacillus cereus M6 isolated from heavy crude oilᵒAPI gravity 11.5 uses to tolerate and/or resist toxic metals. Metal tolerance and removal of Pb(II), Cr(VI), and As(V) was determined. In addition, we evidenced the subcellular distribution of metals, the efflux pump kinetics, and morphological changes in metal-tolerant bacteria. B. cereus M6 exhibited strong tolerance and resistance to the metals evaluated and efficiently removed the metal content by operating efflux pumps and accumulating mainly in membrane fraction. Also, it was found that the model that best fit the efflux corresponds to an equation for resonant oscillations. B. cereus M6 uses mechanisms, including efflux pumps, intracellular and extracellular accumulation in parallel in order to maintain metal levels below a toxic threshold and overcome the effects of high concentrations. These findings are an approach of an energy-dependent efflux system to eliminate excessive amounts of crude oil-associated metals in Bacillus. B. cereus M6 may potentially be useful in designing improved strategies for the bioremediation of soils polluted with metals. Additionally, the prediction model developed would be useful for improving the monitoring of in vitro and in vivo bioremediation processes.

Catalytic ozonation process (COP) is a promising advanced oxidation process for petrochemical wastewater (PCW) treatment. However, the lack of economical and effective catalysts limits its application. Manganese sand ore (MSO) was utilized as a heterogeneous catalyst for ozonation of organic contaminants in PCW in this study. The calcined MSO-assisted COP (cMSO-COP) of aniline exhibited greater degradation than natural MSO-assisted COP or single ozonation process (SOP). The cMSO significantly promoted hydroxyl radical-mediated oxidation, decreased the ozonation activation energy by about 20 %, and doubled the reaction rates in comparison with SOP. The cMSO-COP increased the chemical oxygen demand (COD) removal of PCW twofold relative to SOP. The number of polar organic contaminants decreased by 50 % after cMSO-COP treatment. This study demonstrated the potential use of cMSO for efficient ozonation of petrochemical-derived contaminants at low cost.

We investigated the magnetic and chemical properties of the roadside soil samples collected from five European and Asian countries. Spots in which cars slowed down and/or accelerated due to the traffic organization (speed limits, junctions, and traffic lights) were selected for sampling. Apart from the Zabrze site (Poland), the magnetic susceptibility and heavy metal contents decreased with increasing distance from the road edge. The highest mass-specific magnetic susceptibility values (χ) were observed in the samples collected from Mumbai (India) and Zabrze (Poland). Moreover, the high contents of Fe, Ni, Mn, and Co were observed in Mumbai, whereas in Zabrze, all the examined elements demonstrated high contents, except for Co. Analyses revealed that magnetite was the main magnetic mineral in the roadside soil samples. The high correlation coefficients (r = 0.87) between the magnetic susceptibility values and the total Fe content demonstrated that Fe occurred mainly as ferrimagnetic particles of technogenic origin resulting from traffic emissions. The traffic origin of the pollutants was also confirmed by the increased contents of the typically anthropogenic metals (Pb, Zn, Cd, and Cu) and a good correlation (r = 0.83) between the Ti and Mo contents, which do not occur in natural associations. The ratio between particular polycyclic aromatic hydrocarbons (PAHs) and high content of PAHs typical for car exhaust also implied traffic as their main source.

Problems associated with mining are the disposal of wastes on tailing disposal facilities (TDFs). The aim of this study was to determine the ecotoxicity of gold mine tailings by using earthworm bioassays, earthworm biomarkers and enzymatic analyses. End points included changes in biomass, reproduction, lysosomal membrane stability, tissue metal concentrations, and selected enzymatic activities. Results indicated high concentrations of Ni in the material as well as bioaccumulation of lead and arsenic in the earthworm body tissue after exposure. Enzymatic activity was higher in revegetated tailings than in unrehabilitated tailings. It was concluded that TDF and surrounding areas have an acidic pH which affects earthworms and metal bioavailability. Soil enzymatic activities were a sensitive indicator of metal pollution in mining areas. Growth, reproduction and lysosomal membrane stability of earthworms have also been shown to be sensitive end points to assess the ecotoxic effects of gold TDF.

The soils found in urban remnant patches may be considered anthropogenic inner urban soils—soils within the administrative boundaries of a municipalities influenced by activities adding artefacts into the soils. Such activities include housing, trading, traffic, production, and disposing. The objective of this study is to determine the scope to which field spectroscopy methods can be used to extend the knowledge of urban soils features and components. The spectroscopy techniques are used broadly for determining specific components or for differentiating between known ones. Moreover, this technique is able to determine low concentration in various phases and to trace hazardous material, and most studies are keen on quantification of those hazardous. In this paper, a top–down analysis for detecting the presence of minerals, organic matter, and pollutants in mixed soil samples is developed and presented. The developed method applies spectral activity (SA) detection in a structured hierarchical approach to quickly and, more importantly, accurately identify dominant spectral features. The developed method is adopted by multiple in-production tools including continuum removal normalization, guided by polynomial generalization, and spectral-likelihood algorithms: orthogonal subspace projection (OSP) and iterative spectral mixture analysis (ISMA).

Bioflocculation occurs in both engineered and natural systems and plays an important role in several water treatment processes as well as in pathogen transport and survival. In this study, bioflocculation was simulated in the laboratory to allow for well-controlled experiments. Escherichia coli and latex particles of varying sizes (3.2, 11 and 25 μm) were spiked into a buffer solution and were bioflocculated by adding alginate and varying amounts of calcium (0, 5, 10 and 15 mM). The extent of flocculation was determined by the calcium concentration, and the floc structure was modified by varying the particle size. The bioflocculation process was monitored with a dynamic particle analyzer, and the flocs formed were analyzed with respect to size, shape and porosity parameters. Larger flocs were observed to have a more heterogeneous structure with higher variation in shape and porosity compared to smaller flocs. Circularity and porosity parameters were shown to be strongly correlated with the calcium concentration. In addition, ultraviolet (UV) irradiation experiments were performed on flocculated and non-flocculated samples, and the inactivation data were assessed in light of floc characteristics determined with the particle analyzer.