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The link between descriptors 8 and 9 of the Marine Strategy Framework Directive: lessons learnt in Spain
2014
Gago, J. | Viñas, L. | Besada, V. | Bellas, J.
The aim of this note is to discuss the relevance of the interaction/integration of monitoring of contaminants for the protection of the marine environment and for human health safety (descriptors 8 and 9, respectively) within the Marine Strategy Framework Directive (MSFD). The identification of possible relations between contaminant levels in sediments and tissues of fish and other seafood, as well as the association of those levels to pollution sources, are major challenges for marine researchers. The Spanish initial assessment in the North-East Atlantic marine region was used as an example to show some gaps and loopholes when dealing with the relationship between descriptors 8 and 9. The main problem to deal with is that monitoring programmes intended for the assessment of marine environmental quality and for human health safety usually apply different approaches and methodologies, and even different tissues are analysed in some species (mainly fish). It is therefore recommended to make a profound revision of current sampling strategies, procedures and methodologies, including the selection of target species and tissues and to improve the traceability of samples of fish and other seafood for human consumption. On the other hand, despite the scope of descriptor 9 which is limited to commercially relevant species, this fact should not be an obstacle in the application of the ‘ecosystem approach’ within the MSFD. In order to appropriately solve these shortcomings, an information exchange system between authorities dealing with descriptors 8 and 9 should be strongly encouraged for the next steps of the MSFD’s implementation.
Show more [+] Less [-]Organochlorine pesticides and polychlorinated biphenyls in Tibetan forest soil: profile distribution and processes
2014
Wang, Xiaoping | Xue, Yonggang | Gong, Ping | Yao, Tandong
Tibetan forests are located in the southeastern Tibetan Plateau, where the climate is dominated by the Indian monsoon. Due to the affinity to pollution sources and high organic carbon stocks, the fate of persistent organic pollutants in the Tibetan forests should be given more attention. In this study, seven soil profiles were investigated to obtain the vertical distribution of the organochlorine pesticides and polychlorinated biphenyls (PCBs) in the Tibetan forest soil. The results indicate that the DDTs are highly stable in the soil, with limited volatilization and leaching, while the more volatile PCBs were found in the deeper mineral layer, which means that they can translocate through the organic layer and move farther downward into the deep soil. The air-to-ground fluxes (estimated by the age of the organic layer) of the DDTs are one magnitude higher than those reported in a study on the Alps, suggesting the higher accumulation of DDTs by the Tibetan forest.
Show more [+] Less [-]Comparative quantification of oxygen release by wetland plants: electrode technique and oxygen consumption model
2014
Wu, Haiming | Liu, Jufeng | Zhang, Jian | Li, Cong | Fan, Jinlin | Xu, Xiaoli
Understanding oxygen release by plants is important to the design of constructed wetlands for wastewater treatment. Lab-scale systems planted with Phragmites australis were studied to evaluate the amount of oxygen release by plants using electrode techniques and oxygen consumption model. Oxygen release rate (0.14 g O₂/m²/day) measured using electrode techniques was much lower than that (3.94–25.20 gO₂/m²/day) calculated using the oxygen consumption model. The results revealed that oxygen release by plants was significantly influenced by the oxygen demand for the degradation of pollutants, and the oxygen release rate increased with the rising of the concentration of degradable materials in the solution. The summary of the methods in qualifying oxygen release by wetland plants demonstrated that variations existed among different measuring methods and even in the same measuring approach. The results would be helpful for understanding the contribution of plants in constructed wetlands toward actual wastewater treatment.
Show more [+] Less [-]Adsorption and desorption of 2,4,6-trichlorophenol onto and from ash as affected by Ag⁺, Zn ²⁺, and Al ³⁺
2014
Chen, Guangcai | Wang, Yusheng | Pei, Zhiguo
Metal cations and organic pollutants mostly co-exist in the natural environment. However, their interactions in adsorption processes have yet to be adequately addressed. In the current study, the effect of inorganic cations with different charges (Ag⁺, Zn²⁺, and Al³⁺) on the adsorption and desorption of 2,4,6-trichlorophenol (TCP) onto and from processed ash derived from wheat (Triticum aestivum L.) straw was investigated. The adsorption and desorption of TCP were both nonlinear; the isotherm and kinetics curves fitted well using the Freundlich equation and a pseudo-second-order model, respectively. The presence of Ag⁺ promoted TCP adsorption, while Zn²⁺ and Al³⁺ reduced TCP adsorption onto ash. The desorption of TCP from ash showed obvious hysteresis, and the presence of Ag⁺, Zn²⁺, and Al³⁺ caused the desorption to be less hysteretic. The suppression of TCP adsorption by Zn²⁺ and Al³⁺ was ascribed to the partial overlapping of adsorption groups between TCP and metal ions. Al³⁺ had a stronger inhibition effect than that of Zn²⁺ due to its higher binding capacity and larger hydrated ionic radius than those of Zn²⁺. Enhanced adsorption of TCP onto ash by Ag⁺ was ascribed to its ability to reduce the competitive adsorption of water molecules on ash surface by replacing the original ions, such as Na⁺ and Ca²⁺, and compressing the hydrated ionic radius of these metal ions. In addition, Ag⁺ was able to bind with the aromatic organic compounds containing π-electrons, which resulted in a further increase of TCP adsorption by ash.
Show more [+] Less [-]Nutrient and enzymatic changes of hydrolysed tannery solid waste treated with epigeic earthworm Eudrilus eugeniae and phytotoxicity assessment on selected commercial crops
2014
Ravindran, B. | Contreras-Ramos, S. M. | Wong, J. W. C. | Celvam, Ā. | Sekaran, G.
Animal fleshing (ANFL) is the predominant proteinaceous solid waste generated during processing of leather and it is confronting disposal problems. The aim of this study was to assess the potential of epigeic earthworm Eudrilus eugeniae to utilize and transform the fermented ANFL in the solid state (SSF) and submerged state (SmF) into a value added product along a low residence period (25 days). A total of six treatment units containing different waste mixture compositions were established. Fifty healthy and non-clitellated earthworms were introduced in three different treatment containers: control, SSF, and SmF (+worm). Another set of treatment mixtures (control, SSF, SmF) was established without earthworms (−worm) to compare the results. The products were characterized for physico-chemical, enzymatic analysis and seedling growth parameters to compare the differences in the process with and without earthworms. The changes observed in the analytical parameters were in the following order: SSF > SmF > control mixtures (p < 0.05). The vermicompost showed a significant reduction in heavy metals, total organic carbon and an increase in total Kjeldhal nitrogen as compared to the product untreated by earthworms. The maximum enzymatic activities were observed after 21 days of vermicomposting. The relative seed germination of vermicompost extracts were in the order of tomato (Lycopersicon esculentum) > green gram (Vigna radiata) > cucumber (Cucumis sativus) > bottle gourd (Lagenaria siceraria (Mol.) Standl.) and showed no phytotoxicity effects. The results indicated that the combination of both ANFL hydrolysis through fermentation and vermicomposting is a good alternative to the management of this kind of waste.
Show more [+] Less [-]Biodegradation potential of cyano-based ionic liquid anions in a culture of Cupriavidus spp. and their in vitro enzymatic hydrolysis by nitrile hydratase
2014
Neumann, Jennifer | Pawlik, Magdalena | Bryniok, Dieter | Thöming, Jorg | Stolte, Stefan
Biodegradation tests with bacteria from activated sludge revealed the probable persistence of cyano-based ionic liquid anions when these leave waste water treatment plants. A possible biological treatment using bacteria capable of biodegrading similar compounds, namely cyanide and cyano-complexes, was therefore examined. With these bacteria from the genera Cupriavidus, the ionic liquid anions B(CN)₄⁻, C(CN)₃⁻, N(CN)₂⁻combined with alkaline cations were tested in different growth media using ion chromatography for the examination of their primary biodegradability. However, no enhanced biodegradability of the tested cyano-based ionic liquids was observed. Therefore, an in vitro enzymatic hydrolysis test was additionally run showing that all tested ionic liquid (IL) anions can be hydrolysed to their corresponding amides by nitrile hydratase, but not by nitrilase under the experimental conditions. The biological stability of the cyano-based anions is an advantage in technological application, but the occurrence of enzymes that are able to hydrolyse the parent compound gives a new perspective on future cyano-based IL anion treatment.
Show more [+] Less [-]Phytomanagement of Cd-contaminated soils using maize (Zea mays L.) assisted by plant growth-promoting rhizobacteria
2014
Moreira, Helena | Marques, Ana P. G. C. | Franco, Albina R. | Rangel, António O. S. S. | Castro, Paula M. L.
Zea mays (L.) is a crop widely cultivated throughout the world and can be considered suitable for phytomanagement due to its metal resistance and energetic value. In this study, the effect of two plant growth-promoting rhizobacteria, Ralstonia eutropha and Chryseobacterium humi, on growth and metal uptake of Z. mays plants in soils contaminated with up to 30 mg Cd kg⁻¹was evaluated. Bacterial inoculation increased plant biomass up to 63 % and led to a decrease of up to 81 % in Cd shoot levels (4–88 mg Cd kg⁻¹) and to an increase of up to 186 % in accumulation in the roots (52–134 mg Cd kg⁻¹). The rhizosphere community structure changed throughout the experiment and varied with different levels of Cd soil contamination, as revealed by molecular biology techniques. Z. mays plants inoculated with either of the tested strains may have potential application in a strategy of soil remediation, in particular short-term phytostabilization, coupled with biomass production for energy purposes.
Show more [+] Less [-]Severe particulate pollution from the deposition practices of the primary materials of a cement plant
2014
Kourtidis, K. | Rapsomanikis, S. | Zerefos, C. | Georgoulias, A. K. | Pavlidou, E.
Global cement production has increased twofold during the last decade. This increase has been accompanied by the installation of many new plants, especially in Southeast Asia. Although various aspects of pollution related to cement production have been reported, the impact of primary material deposition practices on ambient air quality has not yet been studied. In this study, we show that deposition practices can have a very serious impact on levels of ambient aerosols, far larger than other cement production-related impacts. Analyses of ambient particulates sampled near a cement plant show 1.3–30.4 mg/m³total suspended particulates in the air and concentrations of particles with a diameter of 10 μm or less at 0.04–3 mg/m³. These concentrations are very high and seriously exceed air quality standards. We unequivocally attribute these levels to outdoor deposition of cement primary materials, especially clinker, using scanning electron microscopy/energy-dispersive X-ray spectroscopy. We also used satellite-derived aerosol optical depth maps over the area of study to estimate the extent of the spatial impact. The satellite data indicate a 33 % decrease in aerosol optical depth during a 10-year period, possibly due to changing primary material deposition practices. Although the in situ sampling was performed in one location, primary materials used in cement production are common in all parts of the world and have not changed significantly over the last decades. Hence, the results reported here demonstrate the dominant impact of deposition practices on aerosol levels near cement plants.
Show more [+] Less [-]Biodegradation of organic pollutants in saline wastewater by halophilic microorganisms: a review
2014
Castillo-Carvajal, Laura C. | Sanz-Martín, José Luis | Barragán-Huerta, Blanca E.
Agro-food, petroleum, textile, and leather industries generate saline wastewater with a high content of organic pollutants such as aromatic hydrocarbons, phenols, nitroaromatics, and azo dyes. Halophilic microorganisms are of increasing interest in industrial waste treatment, due to their ability to degrade hazardous substances efficiently under high salt conditions. However, their full potential remains unexplored. The isolation and identification of halophilic and halotolerant microorganisms from geographically unrelated and geologically diverse hypersaline sites supports their application in bioremediation processes. Past investigations in this field have mainly focused on the elimination of polycyclic aromatic hydrocarbons and phenols, whereas few studies have investigated N-aromatic compounds, such as nitro-substituted compounds, amines, and azo dyes, in saline wastewater. Information regarding the growth conditions and degradation mechanisms of halophilic microorganisms is also limited. In this review, we discuss recent research on the removal of organic pollutants such as organic matter, in terms of chemical oxygen demand (COD), dyes, hydrocarbons, N-aliphatic and N-aromatic compounds, and phenols, in conditions of high salinity. In addition, some proposal pathways for the degradation of aromatic compounds are presented.
Show more [+] Less [-]A fingerprint analysis method for characterization of dissolved organic matter in secondary effluents of municipal wastewater treatment plant
2014
Tang, Xin | Wu, Qian-Yuan | Zhao, Xin | Huang, Huang | Shi, Xiao-Jie | Hu, Hong-Ying
Dissolved organic matter (DOM) in wastewater and reclaimed water is related to water quality, safety, and treatability. In this study, DOM was characterized through a fingerprint analysis method for DOM characterization using resin fractionation followed by size exclusion chromatography (SEC). Resin fractionation was used in the first step to divide the DOM in water samples into six resin fractions, namely, hydrophobic acids (HOA), hydrophobic bases (HOB), hydrophobic neutrals (HON), hydrophilic acids (HIA), hydrophilic bases (HIB), and hydrophilic neutrals (HIN). SEC analysis was then performed to separate each resin fraction into several (n) subfractions with different molecular weights (MW). Thus, the total DOM in the water sample was fractionated into 6n subfractions. After quantification of each subfraction by dissolved organic carbon (DOC), a fingerprint graph was constructed to express the distribution of DOM in the subfractions. The fingerprint analysis method was applied to a secondary effluent sample during ozonation. Ozonation (dose of 10 mg L⁻¹) removed the DOC only by 8 % and reduced UV₂₅₄of the sample by 36 %. Fingerprint graphs also revealed that the resin fractions changed quite limitedly but transformation of subfractions occurred notably.
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