A low-cost microbial fuel cell (MFC) with a brush-shaped anode was constructed with low-cost materials and operated in a fed-batch mode using wastewater as a substrate. The operational performance of the MFC was evaluated considering the organic matter removal, coulombic efficiencies, and current and power densities. Its relative performance to cost was evaluated considering a MFC with platinum/carbon cathode. It was observed that the organic matter removal efficiency was up to 80 % and the coulombic efficiencies varied from 3.5 to 5.7 %. Maximum average voltages and power and current densities of 207 ± 30 mV, 9.2 ± 2.4 mW m-2, and 56.8 ± 14.9 mA m-2 were obtained, respectively. It was observed that the low-cost MFC produced higher power and current densities per dollar when compared to a MFC using platinum-catalyzed electrode. © 2013 Springer Science+Business Media Dordrecht.

High applications of P fertilizers and manure are general practice in intensive agriculture and may cause eutrophication in adjacent streams. Bioavailability of P can be estimated by sequential extractions commonly used for soil or sediment. A single combined method may facilitate more effective comparisons of topsoils and adjoining stream sediments, and enhance management decisions. In this study, the suitability of an established soil P sequential extraction was tested on stream bed sediments. The study was conducted in the Sumas River watershed in the agricultural Lower Fraser Valley, Canada. Sediment samples with differing land use (forest, low and high intensity agriculture) from 1993, 1994, 2008, and 2009 from 14 sites along the Sumas River and tributaries were used. Total sequential extraction concentrations were in agreement with aqua regia digestion (Rs = 0.96) and showed consistency over the study time sequence. P fractions released by 0.5 M NaHCO3 (median 14 %), 0.1 M NaOH (33 %), and 1.0 M HCl (38 %) were significantly (α = 0.05) higher than P released by other extractants. These three extraction steps provide a practical and time-effective assessment of P lability in stream sediments and may be used as a combined scheme for sediment and soil. Analytical results further revealed that land use has a major and characteristic impact on P lability. With a land use change from forest to intensive agriculture, results showed an increase in total P concentrations (30 to 4,000 ppm) and in P lability, in particular for the moderately labile NaOH-P fraction (20 to 50 %). © 2013 Springer Science+Business Media Dordrecht.

Textile industries use large amounts of water in dyeing processes and a wide variety of synthetic dyes. A small concentration of these dyes in the environment can generate highly visible pollution and changes in aquatic ecosystems. Adsorption, biosorption, and biodegradation are the most advantageous dye removal processes. Biodegradation occurs when enzymes produced by certain microorganisms are capable of breaking down the dye molecule. To increase the efficiency of these processes, cell immobilization enables the reuse of the immobilized cells and offers a high degree of mechanical strength, allowing metabolic processes to take place under adverse conditions. The aim of the present study was to investigate the use of Saccharomyces cerevisiae immobilized in activated sugarcane bagasse for the degradation of Acid Black 48 dye in aqueous solutions. For such, sugarcane bagasse was treated with polyethyleneimine (PEI). Concentrations of a 1 % S. cerevisiae suspension were evaluated to determine cell immobilization rates. Once immobilization was established, biodegradation assays for 240 h with free and immobilized yeast in PEI-treated sugarcane bagasse were evaluated by Fourier transform infrared spectrophotometry. The results indicated a probable change in the dye molecule and the possible formation of new metabolites. Thus, S. cerevisiae immobilized in sugarcane bagasse is very attractive for biodegradation processes in the treatment of textile effluents. © 2013 Springer Science+Business Media Dordrecht.

Although Cd concentrations in uncontaminated soils are usually low, pollution of soils by Cd from different sources of contamination pose problems. The application of soil amendments to increase plant production has been used as a viable alternative for recovery of soils contaminated with Cd. However, emphasis needs to be placed on the nature of Cd sorption processes in order that the amendments can be managed appropriately. A range of materials including vermicompost, sugarcane filter cake, palm kernel pie, lime, phosphate rock, and zeolite were used for the sorption studies. Total and nonspecific Cd sorption was estimated by batch experiments, and specific sorption was obtained by the difference between the former and the latter. Best adsorbents for specific Cd sorption from soil amendments were lime and zeolite. Langmuir adsorption isotherms fitted reasonably well in the experimental data, and their constants were evaluated, with R ² values from 0.80 to 0.99. The maximum adsorption capacity of Cd(II) was higher for mineral amendments than for organic amendments and ranged from 0.89 to 10.86 g kg⁻¹. The small value (0.08 L mg⁻¹) of the constant related to the energy of adsorption indicated that Cd was bound weakly to the palm kernel pie. Thermodynamic parameter, the Gibbs free energy, was calculated for each system, and the negative values obtained confirm that the adsorption processes were spontaneous. The values of separation factor, R L, which has been used to predict affinity between adsorbate and adsorbent were between 0 and 1, indicating that sorption was very favorable for Cd(II).

The evaluation of the contribution of natural sources to PM₁₀ and PM₂.₅ concentrations is a priority especially for the countries of European south strongly influenced by Saharan dust transport events. Daily PM₂.₅ concentrations and composition were monitored at an urban site at 14 m above ground level, at the National Technical University of Athens campus from February to December 2010. The typical dust constituents Si, Al, Fe, K, Ca, Mg, and Ti were determined by wavelength dispersive X-ray fluorescence spectrometry (WDXRF). Sulfur, a tracer of anthropogenic origin and major constituent of PM₂.₅, was determined by both WDXRF and ionic chromatography. The contribution of dust and sulfates in PM₂.₅ was calculated from the analytical determinations. An annual mean of 20 μg/m³ was calculated from the mean daily PM₂.₅ concentrations data. Twenty-two per cent of daily concentrations of PM₂.₅ reached or exceeded the EU annual target concentration of 25 μg/m³. The exceedances occurred during 13 short periods of 1–4 days. Back-trajectory analysis was performed for these periods in order to identify the air masses origin. From these periods, ten periods were associated to Saharan dust transport events. The most intense dust transport event occurred between February 17th and 20th and was responsible for the highest recorded PM₂.₅ concentration of 100 μg/m³ where the dust contribution in PM₂.₅ reached 96 %. The other dust transport events were less intense and corresponded to less pronounced enhancements of PM₂.₅ concentrations, and their contribution ranged from 15 to 39 % in PM₂.₅ concentrations. Air masses originated from northwest Africa while the influence of central Sahara was quite smaller.

Although many studies have examined effects of metal mine effluents (MMEs) on receiving environments, few have compared the roles of individual and mixed metals relative to whole effluents. The objective of the present set of studies was to examine whether Cu, Ni, or Se, alone or in a mixture, causes comparable effects to those observed in fathead minnows (Pimephales promelas) exposed to an environmentally relevant MME (45 % process water effluent [PWE]). Metal bioaccumulation, fathead minnow (FHM) morphometrics, and egg production were compared between treatments over a 21-day exposure. FHMs were exposed to similar waterborne concentrations and species of metals in single and mixed metal treatments relative to 45 % PWE. FHMs were also exposed to similar concentrations of metals in single and mixed metal treatments relative to 45 % PWE through the diet (Chironomus dilutus — a representative prey species). However, only FHMs exposed to 45 % PWE had reduced egg production (60–80 % less than controls). Our findings indicate that Cu, Ni, and Se exposures and bioaccumulation did not contribute to decreased reproductive output in FHMs under the conditions that were examined. We also found no evidence to believe that these metals were responsible for decreased egg production in PWE. It is therefore reasonable to suggest that these metals have limited potential to cause reproductive effects in MMEs with similar composition and water chemistry conditions. Overall, this study highlights the importance of examining single and mixed metal exposures prior to suggesting that adverse effects in fish exposed to MMEs occur due to bioaccumulation of metal(s).

Total atmospheric bulk mercury (Hg) concentration and deposition were measured from August 2008 to November 2010 at nine locations in the Northern Great Plains, USA using passive bulk mercury samplers. Monthly mercury concentrations ranged from 1.3 to 51.0 ng L⁻¹ with an overall volume weighted mean of 12.9 ng L⁻¹. Normalized daily Hg fluxes ranged from 0.43 to 110 ng m⁻² day⁻¹ with higher rates occurring during high precipitation months as rainfall during spring and summer. Annual deposition rates ranged from 5.82 to 9.21 μg m⁻² year⁻¹ and were comparable to studies performed at similar latitudes and to estimates from the Mercury Deposition Network (MDN). There was no significant difference (p > 0.05) between measured atmospheric mercury for one colocated bulk Hg sampler and an existing MDN wet-only sampler at Eagle Butte, South Dakota, demonstrating measurement unity between the two sampling techniques in this geographic area.

The development of human society entails increased industrial activity and consequently the release of a large number of chemical substances including solvents, detergents and pharmaceutical products which reach water bodies through the discharge of industrial effluents, damaging the organisms living in these ecosystems. This study aimed to determine oxidative stress induced on the common carp Cyprinus carpio by effluent from a pharmaceutical plant that manufactures nonsteroidal anti-inflammatory drugs. The median lethal concentration and subsequently the lowest observed adverse effect level were determined. Carp were exposed to the latter value (0.1173 %) for different exposure periods (12, 24, 48, 72 and 96 h), and the following biomarkers were evaluated in gill, brain, liver and blood: hydroperoxide content (HPC), lipid peroxidation (LPX), protein carbonyl content (PCC), and the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Statistically significant increases with respect to the control group (P < 0.05) were observed in HPC, LPX and PCC particularly in gill of effluent-exposed specimens. SOD, CAT and GPx activity in gill also increased with respect to the control group. This particular industrial effluent is therefore concluded to induce oxidative stress on C. carpio, this damage being most evident in gill. © 2013 Springer Science+Business Media Dordrecht.

Major incidents involving mine waste facilities and poor environmental management practices have left the legacy of thousands of contaminated sites like in the historic mining areas in the Carpathian Basin. Associated environmental risks have triggered the development of new EU environmental legislation to prevent and minimize the effects of such incidents. The Mine Waste Directive requires the risk-based inventory of all mine waste sites in Europe by May 2012. In order to address the mining environmental problems, a standard risk-based pre-selection protocol has been developed by the EU Commission. The protocol consists of 18 simple questions about contamination source, pathway and receptor. This paper evaluates the protocol by applying it to real-life cases, adopting it to local conditions, comparing to the similar method of the European Environmental Agency standard Preliminary Risk Assessment Model (PRAMS) and by carrying out uncertainty analysis. All together, 145 ore mine waste sites have been selected for scientific testing and evaluation using the EU Mining Waste Directive (MWD) Pre-selection Protocol as a case study from Hungary. The proportion of uncertain responses to questions in the protocol for the mine waste site gives an insight of specific and overall uncertainty in the data used. Questions of the EU MWD Pre-selection Protocol are linked to a GIS system, and key parameters such as the topographic slope and distance to the nearest surface and groundwater bodies to settlements and protected areas are calculated and statistically evaluated in order to adjust the RA models to local conditions in Hungary. Results show that the adjustment of threshold values to local conditions is necessary; however, the EU MWD Pre-selection Protocol is robust and is relatively insensitive to threshold values. Results of the EU MWD Pre-selection Protocol are consistent with the pre-screening European Environmental Agency PRAMS model which further confirms that the Protocol delivers reliable selection results that are not sensitive to the selected parameters. An interesting outcome of the study is that the highest uncertainty is associated with the engineering conditions of the waste facilities, such as the heights and size.

A laboratory-scale study was conducted to determine the removal efficiencies of nine contaminants from a tannery wastewater using a number of physicochemical processes. Coagulation–flocculation using bittern as coagulant, oxidation-utilizing ozone, and adsorption using activated carbon were applied separately and in different sequences. Jar tests were utilized to conduct the experimental work. Except for arsenic, the highest removal efficiencies were recorded when coagulation/flocculation was conducted on the alkalized samples using a bittern dose of 5 mL/L. Activated carbon adsorption improved removal efficiencies of several contaminants. The coagulation/flocculation–adsorption sequence using the optimum dose of 5 mL/L of bittern resulted in high removal efficiencies for total suspended solids (TSS) (97 % ± 1), apparent color (100 % ± 0), turbidity (97 % ± 1), total nitrogen (86 % ± 1), and chromium (100 % ± 0). On the other hand, the same sequence resulted in moderate removal efficiencies for chemical oxygen demand (COD) (72 % ± 7) and total phosphorus (74 % ± 5) and relatively low removals for biochemical oxygen demand (BOD) (55 % ± 10) and arsenic (42 % ± 14). The removal efficiencies for the different tested sequences demonstrated that each sequence did improve the removal efficiencies for most of the parameters tested and consequently, the quality of tannery effluent. However, no single optimum sequence was capable of attaining high removal efficiencies for all nine parameters.