Magnetic particles precipitated onto wheat husk for removal of methyl blue from aqueous solution

Magnetic particles prepared via co-precipitation and impregnated onto wheat husk (MN-WH) were used for the removal of methyl blue (MB) from aqueous solution. Experiments were conducted in a batch mode for optimization regarding pH, contact time, adsorbent dose, initial dye concentrations, and temperature. Maximum adsorption (98%) was achieved at pH 5. The adsorption data were fitted into pseudo-first, pseudo-second, intraparticle diffusion, and Elovich equation revealing that adsorption followed pseudo-second-order kinetics. The four most common isotherm models, i.e. the Langmuir, Freundlich, Tempkin, and Dubinin–Radushkevich (D–R), were used to evaluate the data, with the best fit to a Langmuir isotherm (R² = 0.996), followed by a Freundlich isotherm (R² = 0.995), indicating monolayer adsorption of MB on the surface of MN-WH. Thermodynamic parameters calculated from the Van't Hoff equation revealed that the adsorption is exothermic (ΔHº = ?19.7 kJ mol^?1).     

Global assessment of the non-equilibrium concept in rangelands

The non-equilibrium concept of rangeland dynamics predicts that the potential for grazing-induced degradation is low in rangelands with relatively variable precipitation. To date, evidence in support of the non-equilibrium concept has been inconsistent. Using a standardized protocol, including a newly developed global map of rainfall variability, we reviewed the incidence of degradation in relation to rainfall variability across 58 published studies. We distinguished between (1) zonal degradation (i.e., degradation independent of water and key resources), (2) degradation in the presence of key resources, and (3) degradation in the presence of water. For studies not affected by proximity to permanent water or key resources, we found strong support for the non-equilibrium concept for rangelands. Zonal degradation was absent at CV (coefficient of variation) values above 33%, which has been proposed as a critical threshold. Grazing degradation was almost entirely restricted to areas with relatively stable annual precipitation as expressed by a low CV, or to rangelands with key resources or water points nearby. To better understand rangeland dynamics, we recommend that future studies use globally comparable measures of degradation and rainfall variability. Our work underlines that rangelands with relatively stable rainfall patterns, and those with access to water or key resources, are potentially vulnerable to degradation. Grazing management in such areas should incorporate strategic rest periods. Such rest periods effectively mimic natural fluctuations in herbivore populations, which are a defining characteristic of non-degraded rangelands occurring under highly variable precipitation regimes.     

New epizooic symbioses between sponges of the genera Plakortis and Xestospongia in cryptic habitats of the Caribbean

Three new cases of sponge symbiosis between species of Plakortis and Xestospongia were found in reef caves and mesophotic reef habitats of the Caribbean. Plakortis sp. 1 from the Bahamas associates exclusively with Xestospongia deweerdtae which was originally described living freely on the deep fore-reef and caves of Jamaica. In addition, we found Plakortis sp. 2 from Puerto Rico which associates with both X. deweerdtae and a different Xestospongia sp. Sponge specimens were identified using cytochrome oxidase subunit 1, 28S rRNA and 18S rRNA gene sequence fragments, spicule analysis, and histological sections with SEM. Unlike previous sponge pairs, Xestospongia spp. not only grew as a thin veneer of tissue over the Plakortis host sponge but through the mesohyl, forming inner channels (0.1–1 cm) that may provide a benefit by facilitating more efficient water transport through the dense Plakortis tissue. Symbioses with both Plakortis spp. were documented from an early recruit stage through adulthood. Spicule measurements conducted on symbiotic versus free-living X. deweerdtae revealed significantly smaller spicule sizes for symbiotic individuals, suggesting a cost in terms of silicon availability, or a benefit in terms of a lower investment in skeleton synthesis for support. This study reveals new specialized symbiotic associations between distantly related sponge genera that likely represent an alternative strategy of adaptation for life in reef caves and mesophotic reefs.     

Industrial organic contaminants: identification,toxicity and fate in the environment

Industrialization and urbanization in the more economically developed countries and also in emerging and developing nations have led to an intensive and still increasing use of water resources. The involved chemical contamination led to a deterioration of aquatic systems in many areas. Industries are important pollution sources and the discharged wastewaters may contain very diverse and potentially harmful organic compound groups. We therefore present here a comprehensive review of the current state of knowledge of organic contaminants from industrial wastewaters. The available studies proved the heterogenic chemical composition of industrial wastewaters, even from the same industry branches, and the presence of heterogenic organic contaminant mixtures from industrial sources in aquatic systems. We conclude that our knowledge of the chemical composition of industrial wastewaters and the occurrence of industrial organic contaminants in the environment is as yet very limited. A combination of chemical and toxicological methods enabled the identification of toxic organic constituents in industrial wastewaters. Chemical evaluations of industrial contamination linked to surveys of environmental impacts could relate toxic effects of field samples to the presence of specific contaminants. Exposure experiments in the field proved the bioaccumulation and toxicity of several industrial compounds. Ecological surveys in industrial areas combined with a comprehensive chemical characterization and toxicity evaluation are so far missing. Some of the identified organic contaminants are related to characteristic industrial production processes, and their presence in water, sediment or biota indicates the input of specific industrial wastewaters. Accordingly, these compounds can be used as industrial markers. We suggest the proceeding application of the marker concept, as markers are useful to verify the input of specific industrial wastewaters to aquatic systems and to investigate the spatial distribution of the emission. Such information helps to disentangle different emission sources for the subsequent investigation of potential impacts in the environment.     

On possibilities to estimate local concentration variations with CFD-LES in real urban environments

Environmental Fluid Mechanics - Applied studies with Large Eddy Simulation (LES) of hazardous gas dispersion around buildings in cities have become increasingly feasible due to rapid advancements...     

Artificial lightweight aggregates as utilization for future ashes - A case study

In the future, more electricity in the Netherlands will be produced using coal with co-combustion. Due to this, the generated annual ash volume will increase and the chemical composition will be influenced. One of the options for utilization if present markets are saturated and for use of fly ashes with different compositions, is as raw material for lightweight aggregates. This was selected as one of the best utilizations options regarding potential ash volume to be applied, environmental aspects and status of technology. Because of this, a study has been performed to assess the potential utilization of fly ash for the production of lightweight aggregate. Lightweight aggregate has been produced in a laboratory scale rotary kiln. The raw material consisted of class F fly ash with high free lime content. An addition of 8% clay was necessary to get green pellets with sufficient green strength. The basic properties of the produced lightweight aggregate and its behaviour in concrete have been investigated. The concrete has a good compressive strength and its leaching behaviour meets the most stringent requirements of Dutch environmental regulations. The carbon foot print of concrete will be negatively influenced if only the concrete itself is taken into account, but the reduction of the volume weight has advantages regarding design, transport emissions and isolation properties which may counteract this. In the Dutch situation the operational costs are higher than expected potential selling price for the LWA, which implies that the gate fee for the fly ash is negative.     

Short term effects of copper, sulfadiazine and difloxacin on the anaerobic digestion of pig manure at low organic loading rates

Antibiotics of inorganic and organic origin in pig manure can inhibit the anaerobic process in biogas plants. The influence of three frequently used antibiotics, copper dosed as CuSO₄, sulfadiazine (SDZ), and difloxacin (DIF), on the anaerobic digestion process of pig manure was studied in semi-continuous experiments. Biogas production recovered after every Cu dosage up to a sum of 12.94 g Cu kg⁻¹ organic dry matter (ODM), probably due to Cu precipitation following the formation of sulphide from sulphate. Complete inhibition was found at the very high Cu concentration of 19.40 g Cu kg⁻¹ ODM. Inhibitory effect of SDZ and DIF was observed at concentrations as high as 2.70 g kg⁻¹ ODM and 0.54 g kg⁻¹ ODM, respectively. It seems very unlikely that the antibiotics tested would inhibit the anaerobic process in a full-scale biogas plant.     

Large-scale diversity and biogeography of benthic copepods in European waters

A large-scale database concerning benthic copepods from the Arctic, Baltic Sea, North Sea, British Isles, Adriatic Sea and Crete was compiled to assess species richness, biodiversity, communities, ecological range size and biogeographical patterns. The Adriatic showed the highest evenness and the most species-rich communities. Assemblages from the North Sea, British Isles, Baltic and Crete had a lower evenness. The British Isles were characterised by impoverished communities. The ecological specificity of copepod species showed two diverging trends: higher specificity of species in more diverse assemblages was observed in the Adriatic, North Sea and Baltic. A uniformly high species specificity disregarding sample diversity was found on Crete and in the British Isles. Benthic copepod communities showed distinct patterns that clearly fit the predefined geographical regions. Communities were distinguishable and β-diversity was found to be high around Europe, indicating a high species turnover on the scale of this investigation. The British Isles and the North Sea were found to be faunistic links to the Baltic and the Arctic.     

Differential deposition of antimicrobial proteins in blue tit (Cyanistes caeruleus) clutches by laying order and male attractiveness

Female birds can influence offspring fitness by varying the relative quantities of egg components they deposit within and between clutches. Antimicrobial proteins (lysozyme, ovotransferrin, and avidin) are significant components of the avian albumen and likely aid in defense of embryos from microbial infection. Within clutches, females may enhance antimicrobial defense of early-laid eggs to protect them from the high risk of infection incurred before the onset of incubation. Among entire clutches, females may invest more resources in young sired by more attractive males because they have higher reproductive value. We tested these hypotheses by quantifying antimicrobial protein distribution within and among clutches in blue tit eggs. Contrary to our hypothesis, clutches showed no differential deposition of lysozyme or avidin within clutches, but eggs laid in the middle of the sequence had higher concentrations of ovotransferrin than eggs in the beginning and end. Consistent with our second hypothesis, we found that females produced eggs with higher concentrations of lysozyme (although not ovotransferrin or avidin) when mated to more attractive (more UV-reflective) males. Furthermore, females mated to polygynous males deposited less lysozyme than those mated to monogamous males. These data suggest that allocation of lysozyme at the clutch level may be a maternal effect mediated by male qualities.