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The variations of aluminium species in mountainous forest soils and its implications to soil acidification
2015
Bradová, Monika | Tejnecký, Václav | Borůvka, Luboš | Němeček, Karel | Ash, Christopher | Šebek, Ondřej | Svoboda, Miroslav | Zenáhlíková, Jitka | Drábek, Ondřej
Aluminium (Al) speciation is a characteristic that can be used as a tool for describing the soil acidification process. The question that was answered is how tree species (beech vs spruce) and type of soil horizon affect Al speciation. Our hypotesis is that spruce and beech forest vegetation are able to modify the chemical characteristics of organic horizon, hence the content of Al species. Moreover, these characteristics are seasonally dependent. To answer these questions, a detailed chromatographic speciation of Al in forest soils under contrasting tree species was performed. The Jizera Mountains area (Czech Republic) was chosen as a representative mountainous soil ecosystem. A basic forestry survey was performed on the investigated area. Soil and precipitation samples (throughfall, stemflow) were collected under both beech and spruce stands at monthly intervals from April to November during the years 2008–2011. Total aluminium content and Al speciation, pH, and dissolved organic carbon were determined in aqueous soil extracts and in precipitation samples. We found that the most important factors affecting the chemistry of soils, hence content of the Al species, are soil horizons and vegetation cover. pH strongly affects the amount of Al species under both forests. Fermentation (F) and humified (H) organic horizons contain a higher content of water extractable Al and Al³⁺ compared to organo-mineral (A) and mineral horizons (B). With increasing soil profile depth, the amount of water extractable Al, Al³⁺ and moisture decreases. The prevailing water-extractable species of Al in all studied soils and profiles under both spruce and beech forests were organically bound monovalent Al species. Distinct seasonal variations in organic and mineral soil horizons were found under both spruce and beech forests. Maximum concentrations of water-extractable Al and Al³⁺ were determined in the summer, and the lowest in spring.
显示更多 [+] 显示较少 [-]Biodegradation of polycyclic aromatic hydrocarbons by Trichoderma species: a mini review
2015
Zafra, German | Cortés-Espinosa, Diana V.
Fungi belonging to Trichoderma genus are ascomycetes found in soils worldwide. Trichoderma has been studied in relation to diverse biotechnological applications and are known as successful colonizers of their common habitats. Members of this genus have been well described as effective biocontrol organisms through the production of secondary metabolites with potential applications as new antibiotics. Even though members of Trichoderma are commonly used for the commercial production of lytic enzymes, as a biological control agent, and also in the food industry, their use in xenobiotic biodegradation is limited. Trichoderma stands out as a genus with a great range of substrate utilization, a high production of antimicrobial compounds, and its ability for environmental opportunism. In this review, we focused on the recent advances in the research of Trichoderma species as potent and efficient aromatic hydrocarbon-degrading organisms, as well as aimed to provide insight into its potential role in the bioremediation of soils contaminated with heavy hydrocarbons. Several Trichoderma species are associated with the ability to metabolize a variety of both high and low molecular weight polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, phenanthrene, chrysene, pyrene, and benzo[a]pyrene. PAH-degrading species include Trichoderma hamatum, Trichoderma harzianum, Trichoderma reesei, Trichoderma koningii, Trichoderma viride, Trichoderma virens, and Trichoderma asperellum using alternate enzyme systems commonly seen in other organisms, such as multicooper laccases, peroxidases, and ring-cleavage dioxygenases. Within these species, T. asperellum stands out as a versatile organism with remarkable degrading abilities, high tolerance, and a remarkable potential to be used as a remediation agent in polluted soils.
显示更多 [+] 显示较少 [-]Dioxin risk assessment: mechanisms of action and possible toxicity in human health
2015
Tavakoly Sany, Seyedeh Belin | Hashim, Rosli | Salleh, Aishah | Rezayi, Majid | Karlen, David J | Razavizadeh, Bi Bi Marzieh | Abouzari-lotf, Ebrahim
Dioxin-like compounds (DLCs) have been classified by the World Health Organization (WHO) as one of the most persistent toxic chemical substances in the environment, and they are associated with several occupational activities and industrial accidents around the world. Since the end of the 1970s, these toxic chemicals have been banned because of their human toxicity potential, long half-life, wide dispersion, and they bioaccumulate in the food web. This review serves as a primer for environmental health professionals to provide guidance on short-term risk assessment of dioxin and to identify key findings for health and exposure assessment based on policies of different agencies. It also presents possible health effects of dioxins, mechanisms of action, toxic equivalency factors (TEFs), and dose–response characterization. Key studies related to toxicity values of dioxin-like compounds and their possible human health risk were identified through PubMed and supplemented with relevant studies characterized by reviewing the reference lists in the review articles and primary literature. Existing data decreases the scope of analyses and models in relevant studies to a manageable size by focusing on the set of important studies related to the perspective of developing toxicity values of DLCs.
显示更多 [+] 显示较少 [-]Biofouling of marbles by oxygenic photosynthetic microorganisms
2015
Karaca, Zeki | Öztürk, Ayten | Çolak, Emel
Phototrophic microorganisms disfigure the surfaces of different types of stone. Stone structure is damaged by the activity of photoautotrophic and other microorganisms. However, to date few, investigations have been undertaken into the relationship between microorganisms and the properties of different types of marble. In this study, biological activity of photoautotrophic microorganisms on three types of marble (Yatagan White, Giallo Anticato and Afyon White) was investigated under laboratory conditions over a short period of time. The three types of marble supported the growth of phototrophic microbial communities on their outer and inner layers, turning their original colour from white to a yellowish green colour. The porosity of the marble types facilitated filamentous microbial growth in the presence of water. Scanning electron microscope analysis revealed the accumulation of aggregates such as small spherical, fibrillar, calcified globular bodies on the inner surfaces of the marbles. This suggests that the microscopic characteristics of particular marble types may stimulate the growth of certain types of microorganisms.
显示更多 [+] 显示较少 [-]Calcium affecting protein expression in longan under simulated acid rain stress
2015
Pan, Tengfei | Li, Yongyu | Ma, Cuilan | Qiu, Dongliang
Longan (Dimocarpus longana Lour. cv. Wulongling) of uniform one-aged seedlings grown in pots were selected to study specific proteins expressed in leaves under simulated acid rain (SiAR) stress and exogenous Ca²⁺ regulation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results showed that there was a protein band specifically expressed under SiAR of pH 2.5 stress for 15 days with its molecular weight of about 23 kD. A 17 kD protein band specifically expressed after SiAR stress 5 days. Compared with pH 2.5, the pH 3.5 of SiAR made a less influence to protein expression. Two-dimensional electrophoresis (2-DE) results showed that six new specific proteins including C₄ (20.2 kD pI 6.0), F (24 kD pI 6.35), B₃ (22.3 kD pI 6.35), B₄ (23.5 kD pI 6.5), C₅ (21.8 kD pI 5.6), and C₆ (20.2 kD pI 5.6) specifically expressed. C₄ always expressed during SiAR stress. F expressed under the stress of pH 2.5 for 15 days and expressed in all pH SiAR stress for 20 days. The expression of proteins including B₃, C₅, and C₆ was related to pH value and stress intensity of SiAR. The expression of B₄ resulted from synergistic effects of SiAR and Ca. The expression of G₁ (Mr 19.3 kD, pI 4.5), G₂ (Mr 17.8 kD, pI 4.65), G₃ (Mr 16.6 kD, pI 4.6), and G₄ (Mr 14.7 kD, pI 4.4) enhanced under the treatment of 5 mM ethylene glycol tetraacetic acid (EGTA) and 2 mM chlorpromazine (CPZ). These proteins showed antagonistic effects and might be relative to the Ca-calmodulin (Ca-CaM) system of longan in response to SiAR stress.
显示更多 [+] 显示较少 [-]Fate of parasites and pathogenic bacteria in an anaerobic hybrid reactor followed by downflow hanging sponge system treating domestic wastewater
2015
Tawfik, A. | El-Zamel, T. | Herrawy, A. | El-Taweel, G.
Treatment of domestic wastewater in a pilot-scale upflow anaerobic hybrid (AH) reactor (0.9 m³) in combination with downflow hanging sponge (DHS) system (1.3 m³) was investigated. The combined system was operated at a hydraulic retention time (HRT) of 6.0 h for AH and 3.2 h for DHS system. The total process achieved a substantial reduction of CODₜₒₜₐₗ resulting in an average effluent concentration of only 39 ± 12 mg/l. Moreover, 90 ± 7 % of ammonia was eliminated in the DHS system. Nitrate and nitrite data revealed that 49 ± 3.2 % of the ammonia removal occurred through nitrification process. The removal efficiency of total coliform (TC), fecal coliform (FC), and fecal streptococci (FS) was relatively low in the AH reactor. The major portion of TC, FC, and FS was removed in the DHS system resulting to an average count of 1.7 × 10⁵ ± 1.1 × 10²/100 ml for TC, 7.1 × 10⁴ ± 1.2 × 10²/100 ml for FC, and 7.5 × 10⁴ ± 1.3 × 10²/100 ml for FS in the final effluent. Likely, the combined system was very efficient for the removal of protozoological species such as sarcodins (Entamoeba cysts), flagellates (Giardia cysts), and ciliates (Balantidium cysts). This was not the case for coccidia (Cryptosporidium oocysts), where 36.4 and 27.3 % were detected in the effluent of AH and DHS system, respectively. Only 10 % of intestinal nematode and cestode ova were recorded in the effluent of AH reactor and were completely removed in the DHS system.
显示更多 [+] 显示较少 [-]Influence of alum on cyanobacterial blooms and water quality of earthen fish ponds
2015
Dawah, Aida | Soliman, Ashraf | Abomohra, Abd El-Fatah | Battah, Mohamed | Anees, Doaa
Eruption of blue-green algal blooms occurs frequently in eutrophic lakes and fish ponds, with associated unpleasant odor and horrid scums. In the present study, we conducted a pre-test experiment in 3 m³ outdoor concrete ponds to determine the optimum concentration of aluminum sulfate (alum) required for reduction of the cyanobacterial blooms without negative effect on fish growth. As a consequence, 10 mg L⁻¹ alum was named as the optimum concentration that was applied in 1000 m³ earthen fish ponds. Obtained results showed that Secchi disc values significantly increased from 10 to 24 cm after 14 days of alum application. Alum-treated ponds showed a reduction in total phytoplankton counts by 94 and 96 % compared to the corresponding controls after 10 and 14 days, respectively. Abundance of blue-green algae in the treated ponds was decreased by 98 % compared to the corresponding control after 14 days of alum application. Consequently, dissolved oxygen, pH, total phosphorus, orthophosphate, and chlorophyll “a” content declined significantly. Our study revealed that using 10 mg L⁻¹ of alum is an effective way to control cyanobacterial blooms in eutrophic waters, especially in fish ponds, without negative effect in water quality.
显示更多 [+] 显示较少 [-]Dioxin formation and control in a gasification–melting plant
2015
Kawamoto, Katsuya | Miyata, Haruo
We investigated dioxin formation and removal in a commercial thermal waste treatment plant employing a gasification and melting process that has become widespread in the last decade in Japan. The aim was to clarify the possibility of dioxin formation in a process operation at high temperatures and the applicability of catalytic decomposition of dioxins. Also, the possible use of dioxin surrogate compounds for plant monitoring was further evaluated. The main test parameter was the influence of changes in the amount and type of municipal solid waste (MSW) supplied to the thermal waste treatment plant which from day to day operation is a relevant parameter also from commercial perspective. Here especially, the plastic content on dioxin release was assessed. The following conclusions were reached: (1) disturbance of combustion by adding plastic waste above the capability of the system resulted in a considerable increase in dioxin content of the flue gas at the inlet of the bag house and (2) bag filter equipment incorporating a catalytic filter effectively reduced the gaseous dioxin content below the standard of 0.1 ng toxic equivalency (TEQ)/m³ N, by decomposition and partly adsorption, as was revealed by total dioxin mass balance and an increased levels in the fly ash. Also, the possible use of organohalogen compounds as dioxin surrogate compounds for plant monitoring was further evaluated. The levels of these surrogates did not exceed values corresponding to 0.1 ng TEQ/m³ N dioxins established from former tests. This further substantiated that surrogate measurement therefore can well reflect dioxin levels.
显示更多 [+] 显示较少 [-]Assessment of metal pollution associated with an alteration area: Old Gümüşhane, NE Black Sea
2015
Vural, Alaaddin
The objective of this study was to determine the potential environmental risks associated with the Kirkpavli (Old Gümüşhane in northern Turkey) alteration area by quantifying pollution in soil. The Kirkpavli (Old Gümüşhane) alteration area is situated at the south of the deposit with the same name of gold-silver-bearing lead, zinc, and copper in the southern part of the Black Sea Tectonic Unit (Eastern Pontides). In this study, 28 soil samples acquired from the alteration area were analyzed for contents of some main elements including lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd), cobalt (Co), manganese (Mn), nickel (Ni), and arsenic (As). Contents of the elements in the area were determined, and high values were obtained such as 1,171 mg/kg for As, 12.4 mg/kg for Cd, 77.3 mg/kg for Co, 341 mg/kg for Cu, 1,172 mg/kg for Mn, 51.9 mg/kg for Ni, 3,725 mg/kg for Pb, and 880 mg/kg for Zn. Soil contamination was appraised on the basis of Geoaccumulation Index (Igₑₒ), Enrichment Factor (EF), Pollution Index, and Integrated Pollution Index. The calculated results of Igₑₒ, EF, and PI of the elements can be shown in descending order of parameters as As > Pb > Cd > Zn > Cu > Co > Mn. The parameters for some of these elements indicated extremely high contamination (Igₑₒ > 5), extremely high enrichment (EF > 40), and high pollution (PI > 3). High Igₑₒ, EF, and PI values of As, Pb, and Cd in the soil samples mean that soil pollution is typically associated with alteration area. Considering its location and the results of this study, the Kirkpavli alteration area is a significant source of pollution and may have ecotoxicological effects on terrestrial, groundwater, and aquatic ecosystems in the region.
显示更多 [+] 显示较少 [-]Respective contributions of diet and medium to the bioaccumulation of pharmaceutical compounds in the first levels of an aquatic trophic web
2015
Orias, Frédéric | Simon, Laurent | Perrodin, Yves
Nowadays, pharmaceuticals (PCs) are ubiquitous in aquatic ecosystems. It is known that these compounds have ecotoxic effects on aquatic organisms at low concentrations. Moreover, some of them can bioaccumulate inside organisms or trophic webs exposed at environmental concentrations and amplify ecotoxic impacts. PCs can bioaccumulate in two ways: exposure to a medium (e.g., respiration, diffusion, etc.) and/or through the dietary route. Here, we try to assess the respective contributions of these two forms of contamination of the first two levels of an aquatic trophic web. We exposed Daphnia magna for 5 days to 0, 5, and 50 μg/L ¹⁵N-tamoxifen and then fed them with control and contaminated diets. We used an isotopic method to measure the tamoxifen content inside the daphnids after several minutes’ exposure and every day before and after feeding. We found that tamoxifen is very bioaccumulative inside daphnids (BCF up to 12,000) and that the dietary route has a significant impact on contamination by tamoxifen (BAF up to 22,000), especially at low concentrations in medium.
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