Flux of dissolved inorganic nitrogen (DIN—primarily nitrate) from terrestrial ecosystems has been considered an important contributor to acidification of linked aquatic systems. The basis of this concern is the nitrogen (N) saturation hypothesis, positing that additions of N to terrestrial ecosystems in excess of biological requirements will result in DIN leaching. There is a consensus (implicit hypothesis) in the literature that atmospheric deposition of DIN in excess of a threshold of approximately 10 kg ha−1 year−1 leads to significant flux. Diverse data from USA indicate that DIN flux is highly variable both in space and time; the spatial uncertainty as measured by the pooled coefficient of variation is about 0.95, and the temporal (inter-year) uncertainty is about 0.75. The relationship between atmospheric deposition of DIN and annual flux is near-linear within the range of current deposition for US sites (≤8 kg ha−1 year−1 wet deposition). If wet and dry depositions are approximately equal, over 85 % of total DIN deposition is retained. This is nearly equal to the retention reported by the US Geological Survey National Water-Quality Assessment Program, which considered all nonpoint sources of N as inputs and both DIN and organic N as fluxes. Although input–output data have high uncertainty, the 85 % retention of atmospheric DIN by terrestrial watersheds casts doubt on its importance as a contributor to aquatic acidification. There is no obvious threshold of deposition leading to DIN leaching. The nitrogen saturation hypothesis may not fully explain N behavior in terrestrial ecosystems.

In the transition from a fossil to a bio-based economy, it has become an important challenge to maximally recuperate and recycle valuable nutrients coming from manure and digestate processing. Membrane filtration is a suitable technology to separate valuable nutrients in easily transportable concentrates which could potentially be re-used as green fertilizers, in the meantime producing high quality water. However, traditional membrane filtration systems often suffer technical problems in waste stream treatment. The aim of this study was to evaluate the performance of vibratory shear enhanced processing (VSEP) in the removal of macronutrients (N, P, K, Na, Ca, Mg) from the liquid fraction of digestates, reducing their concentrations down to dischargeable/re-usable water. In addition, the re-use potential of VSEP-concentrates as sustainable substitutes for fossil-based mineral fertilizers was evaluated. Removal efficiencies for N and P by two VSEP filtration steps were high, though not sufficient to continuously reach the Flemish legislation criteria for discharge into surface waters (15 mg N l−1 and 2 mg P l−1). Additional purification can occur in a subsequent lagoon, yet further optimization of the VSEP filtration system is advised. Furthermore, concentrates produced by one membrane filtration step showed potential as N–K fertilizer with an economic value of <euro>6.3 ±â€‰1.1 t−1 fresh weight (FW). Further research is, however, required to evaluate the impact on crop production and soil quality by application of these new potential green fertilizers.

Increasing environmental pollution is connected with broad applications of dyes and imperfection of dyeing technology. Decolourization of triphenylmethane brilliant green and disazo Evans blue by bacterial and fungal strains and toxicity (phyto- and zootoxicity) of degradation by-products were investigated. Influence of incubation method on dyes removal was evaluated (static, semi-static, shaken). Dead biomass was used for sorption estimation. Toxicity of treated dyes was measured to estimate possible influence on aquatic ecosystems. The zootoxicity test was done with Daphnia magna and phytotoxicity with Lemna minor. Samples were classified according to ACE 89/BE 2/D3 Final Report Commission EC. The best results of removal for all tested strains were reached in shaken samples. In opposite to fungi, bacterial strains decolourized brilliant green more effectively than Evans blue. The most effective bacterial strain was Erwinia spp. (s12) and fungal strains were Polyporus picipes (RWP17) and Pleurotus ostreatus (BWPH and MB). Decolourization of brilliant green was connected with decrease of zootoxicity (D. magna) and phytotoxicity (L. minor). Removal of Evans blue was connected with no changes in zootoxicity and decrease of phytotoxicity in most of samples.

With the development of the textile industry, there has been a demand for dye removal from contaminated effluents. In recent years, attention has been directed toward various natural solid materials that are capable of removing pollutants from contaminated water at low cost. One such material is sugarcane bagasse. The aim of the present study was to evaluate adsorption of the dye Acid Violet Alizarin N with different concentrations of sugarcane bagasse and granulometry in agitated systems at different pH. The most promising data (achieved with pH 2.5) was analyzed with both Freundlich and Langmuir isotherms equations. The model that better fits dye adsorption interaction into sugarcane bagasse is Freundlich equation, and thus the multilayer model. Moreover, a smaller bagasse granulometry led to greater dye adsorption. The best treatment was achieved with a granulometry value lower than 0.21 mm at pH 2.50, in which the total removal was estimated at a concentration of 16.25 mg mL−1. Hence, sugarcane bagasse proves to be very attractive for dye removal from textile effluents.

The present work focused on treatment of eosin (EO) by photocatalysis (PC) combined with electrocatalysis (EC) process. Bismuth oxychloride/titanium dioxide (BiOCl/TiO₂) hybrid particles, which were used as new heterogeneous photocatalysts, were exploited in a reverse microemulsion approach and were characterized by XRD, UV–Vis diffuse spectra, BET, and SEM technologies. All degradation experiments were performed using a self-assemble experimental setup, in which PC and EC could be carried out simultaneously or individually. The results indicated that BiOCl/TiO₂ showed enhanced photocatalytic performance under UV irradiation, and 50% BiOCl/TiO₂ exhibited the best photoactivity due to its high degree of crystallization, the mesoporous structure and corresponding large special surface area, improved absorption ability in UV region, and the heterojunction formed between two coupling particles. The combined degradation process displayed synergistic effect on the degradation of EO owing to the generation of H₂O₂ at graphite cathode. The parameters such as, pH, reaction current, and initial concentration of EO were monitored in order to optimize the operating conditions. Pseudo-first-order kinetics was proposed and roughly fitted the combined degradation of EO. The combined system in this work suggested a new research idea for the degradation of dye wastewater.

This review addresses the quantification of anthropogenic pollutants in lacustrine sediments by multidisciplinary analyses including: chronostratigraphy using radioisotopes (¹³⁷Cs) and radiocarbon dates (¹⁴C), trace metal analysis, faecal indicator analysis, as well as antibiotic-resistant genes by molecular analysis. Sediment cores from lakes Lucerne and Geneva that are located at a distance of 150 km from each other reveal a synchronous increase in anthropogenic trace metals (Pb, Cu, Zn, and Mn) following the industrial revolution in Europe about 1850. In both lakes, the peak of water pollution by toxic metals due to discharge of industrial wastewaters was reached in the middle of the twentieth century. During the second part of the twentieth century, both sites show a decrease in metal pollution following the implementation of wastewater treatment plants. On the contrary, the Vidy Bay of Lake Geneva where the treated wastewaters from the city of Lausanne are released since 1964 points out a dramatic increase in trace metal deposition. Later, a high increase in organic matter deposition, in bacteria (Escherichia coli and Enterococcus faecalis) activity as well as antibiotic-resistant genes and bacteria occurred into the bay, simultaneously with the eutrophication of the large and deep perialpine lakes in the 1970s due to excessive external nutrient loading.

Compositions of the xylem fluid of arsenic (As)-stressed hydroponic barley (Hordeum vulgare L. cv. Minorimugi) were investigated. The seedlings were treated with 0, 6.7, 33.5, and 67 μM As in the form of arsenite. The xylem fluids were collected from the cut surface of plants 14 days after treatments and analyzed. Arsenic toxicity reduced the flow rate of xylem fluid. Mineral concentrations of the xylem fluid were measured with particle-induced X-ray emission system, but organic solutes were measured with high-performance liquid chromatography. Arsenic did not influence the concentrations of phosphorus (P), potassium (K), magnesium (Mg), and iron (Fe) very much. However, the concentrations of manganese (Mn), zinc (Zn), and copper (Cu) increased resulting in fairly stable translocation of the elements. The concentration and translocation of Ca decreased in the xylem fluid with increasing As concentrations in the medium. Arsenic concentration increased with increasing As in the nutrient solution, but its translocation decreased. Arsenic treatments did not affect phytosiderophore concentration very much, but their translocation decreased. The concentration of citrate increased but that of malate and succinate decreased in 33.5 μM As-treated plants.

Field management is expected to influence nitrous oxide (N₂O) production from arable cropping systems through effects on soil physics and biology. Measurements of N₂O flux were carried out on a weekly basis from April 2008 to August 2009 for a spring sown barley crop at Oak Park Research Centre, Carlow, Ireland. The soil was a free draining sandy loam typical of the majority of cereal growing land in Ireland. The aims of this study were to investigate the suitability of combining reduced tillage and a mustard cover crop (RT–CC) to mitigate nitrous oxide emissions from arable soils and to validate the DeNitrification–DeComposition (DNDC) model version (v. 9.2) for estimating N₂O emissions. In addition, the model was used to simulate N₂O emissions for two sets of future climate scenarios (period 2021–2060). Field results showed that although the daily emissions were significantly higher for RT–CC on two occasions (p < 0.05), no significant effect (p > 0.05) on the cumulative N₂O flux, compared with the CT treatment, was found. DNDC was validated using N₂O data collected from this study in combination with previously collected data and shown to be suitable for estimating N₂O emissions (r ² = 0.70), water-filled pore space (WFPS) (r ² = 0.58) and soil temperature (r ² = 0.87) from this field. The relative deviations of the simulated to the measured N₂O values with the 140 kg N ha⁻¹ fertiliser application rate were −36 % for RT–CC and −19 % for CT. Root mean square error values were 0.014 and 0.007 kg N₂O–N ha⁻¹ day⁻¹, respectively, indicating a reasonable fit. Future cumulative N₂O fluxes and total denitrification were predicted to increase under the RT–CC management for all future climate projections, whilst predictions were inconsistent under the CT. Our study suggests that the use of RT–CC as an alternative farm management system for spring barley, if the sole objective is to reduce N₂O emissions, may not be successful.

The mining exploitation of metallic sulphides, together with the activities associated to the mineral treatment and smelting, when maintained through centuries due to the wealth of the ores, generate important accumulations of wastes in structures of different kind of tailing dams and ponds, for instance. When no previous corrective steps are taken, as usually happens in old exploitations, this means a serious risk of environmental pollution, due to the mobilisation of heavy metals. The present study has been carried out in a mining district, actively exploited during the last two millennia, that was the first world’s producer of lead during some periods (Linares-La Carolina, southern Spain). In this district, the mining activity was associated to a philonian network of metallic sulphurs and ended by the 1980s of the past century. The ancient mining operations, mostly subterranean, have generated large accumulations of residues without any prior corrective action. Therefore, this work intends to characterise these mining dams and determine the influence of these mining wastes on the quality of surface and ground waters. With this goal, three structures that store the mining refuse of different mineralogical origin have been selected. First, a geochemical characterisation of the soil was performed in the area surrounding each of the structures. In all cases, high levels of trace elements (including Pb, Zn, Cu, Cd, Mn, As, Sb and Ba) were observed. A hydrochemical study revealed the mobilisation through the aqueous medium of certain contaminants from the leachate of these ancient accumulations; these contaminants will flow to the streams that drain the area or to the aquifers of the sector. The internal characterisation of these structures was performed with geophysical techniques, specifically electrical resistivity imaging (ERI). The six generated resistivity models have allowed the identification of the morphology of the structures, variations in the vertical and horizontal distribution of the deposited material, fracture zones, water content and reload–unload zones and the contact of the mining wastes with the substrate. Thus, the ERI study confirms the lack of impermeabilisation measures for the terrain in the spill zones in all three cases, which indicates a high risk of contamination of the soil and waters. The obtained images also permit the identification of the ideal positions to conduct future borehole controls.

Filamentous fungi derived from marine environments are well known as a potential genetic resource for various biotechnological applications. Although terrestrial fungi have been reported to be highly efficient in the remediation of xenobiotic pollutants, fungi isolated from the marine environment may possess biological advantages over terrestrial fungi because of their adaptations to high salinity and pH extremes. The present study describes the production of ligninolytic enzymes under saline and non-saline conditions and the decolorization of Remazol Brilliant Blue R (RBBR) dye by three basidiomycetes recovered from marine sponges (Tinctoporellus sp. CBMAI 1061, Marasmiellus sp. CBMAI 1062, and Peniophora sp. CBMAI 1063). Ligninolytic enzymes were primarily produced by these fungi in a salt-free malt extract and malt extract formulated with artificial seawater (saline condition). CuSO₄ and wheat bran were the best inducers of lignin peroxidase and manganese peroxidase activity. RBBR was decolorized up to 100% by the three fungi, and Tinctoporellus sp. CBMAI 1061 was the most efficient. Our results revealed the biotechnological potential of marine-derived basidiomycetes for dye decolorization and the treatment of colored effluent as well as for the degradation of other organopollutants by ligninolytic enzymes in non-saline and saline conditions that resemble the marine environment.