خيارات البحث
النتائج 2381 - 2390 من 62,084
Reactivity and fate of secondary alkane sulfonates (SAS) in marine sediments
Baena Nogueras, Rosa María | Rojas Ojeda, Patricia | Sanz, José Luis | González Mazo, Eduardo | Lara Martín, Pablo Antonio | Química Física
This research is focused on secondary alkane sulfonates (SAS), anionic surfactants widely used in household applications that access aquatic environments mainly via sewage discharges.We studied their sorption capacity and anaerobic degradation in marine sediments, providing the first data available on this topic. SAS partition coefficients increased towards those homologues having longer alkyl chains(from up to 141 L kg 1 for C14 to up to 1753 L kg 1 for C17), which were those less susceptible to undergo biodegradation. Overall, SAS removal percentages reached up to 98% after 166 days of incubation using anoxic sediments. The degradation pathway consisted on the formation of sulfocarboxylic acids after an initial fumarate attack of the alkyl chain and successive b-oxidations. This is the first study showing that SAS can be degraded in absence of oxygen, so this new information should be taken into account for future environmental risk assessments on these chemicals.
اظهر المزيد [+] اقل [-]Restoration of Vegetation in Relation to Soil Properties of Spoil Heap Heavily Contaminated with Heavy Metals
Marek Pająk | Ewa Błońska | Marta Szostak | Michał Gąsiorek | Marcin Pietrzykowski | Otmar Urban | Piotr Derbis
The main objectives of our study were to evaluate soil contamination on a zinc-lead spoil heap in the Upper Silesian Industrial Region in southern Poland using pollution indices, and to investigate the relation between soil properties and the natural succession of vegetation. Organic carbon and nitrogen, pH, soil texture, base cations, and heavy metal content were analyzed in soil samples at depths of 0–15 cm below the organic horizon over a regular grid of 14 sampling plots. The contents of Zn, Pb, and Cd exceeded by several times the acceptable thresholds. Measurements of soil enzyme activity were used to evaluate the progress of vegetation development in relation to soil chemical properties. The results indicate that heavy metals had a significant impact on soil enzyme activity and the development of vegetation cover. High contents of Pb and Cd reduced enzyme activity, while this activity increased with increasing amounts of soil organic matter. Further, the accumulative capacities of heavy metals in needles of Scots pine (Pinus sylvestris L.) and aboveground biomass of bladder campion (Silene vulgaris (Moench) Garcke) were examined. A high accumulation of Zn, Pb, and Cd in the aboveground tissues of S. vulgaris indicated an unusual tolerance of this species to heavy metals and the possibility of using this species in phytoremediation of post-industrial sites. | Soil contamination, Microbial activity, Phytoremediation, Silene vulgaris, Pinus sylvestris | 25 | 1-15 | 12
اظهر المزيد [+] اقل [-]Reclamation of coal mine spoil and its effect on Technosol quality and carbon sequestration: a case study from India
Jitendra Ahirwal | Adarsh Kumar | Marcin Pietrzykowski | Subodh Kumar Maiti
A field study was carried out to assess the impact of revegetation on Technosol quality in the post-mining sites (Central Coalfield Limited, India). The study evaluated community structure, biodiversity, Technosol quality, and carbon (C) dynamics in the postmining ecosystem (PME). The multivariate statistical tool was used to identify the key soil properties, and soil quality was evaluated by using Technosol quality index (TQI). One unreclaimed site (0 years) and four chronosequences revegetated coal mine sites (3, 7, 10, and 15 years) were studied and compared with an undisturbed forest as a reference site. Plant biodiversity indices [Shannon index of diversity (2.42) and Pielou’s evenness (0.97) and Patric richness (12)] were highest in 15-year-old revegetated sites. Soil physicochemical and biological properties were recovered with the revegetation age. Soil organic C (SOC) stock significantly increased from 0.75 Mg C ha−1 in 3 years to 7.60 Mg C ha−1 after 15 years of revegetation in top 15 cm of soils. Ecosystem C pool increased at a rate of 5.38 Mg C ha−1 year−1 . Soil CO2 flux was significantly increased from 0.27 μmol CO2 m−2 s −1 in unreclaimed sites to 3.19 μmol CO2 m−2 s −1 in 15-year-old revegetated site. Principal component analysis (PCA) showed that dehydrogenase activity (DHA), available nitrogen (N), and silt content were the key soil parameters that were affected by reclamation. A 15-yearold Technosol had a greater TQI (0.78) compared to the control forest soils (0.64) that indicated the suitability of revegetation to recuperate soil quality in mining-degraded land and to increase C sequestration potential. | Revegetation, Biodiversity, Dehydrogenase activity, Indicator, SoilCO2 flux | 30 | 27992-28003 | 28
اظهر المزيد [+] اقل [-]Protective effect of melatonin on cadmium-induced changes in some maturation and reproductive parameters of female Prussian carp (Carassius gibelio B.)
Ewa Drąg-Kozak | Magdalena Socha | Grzegorz Gosiewski | Ewa Łuszczek-Trojnar | Jarosław Chyb | Włodzimierz Popek
The aim of this study was to determine whether melatonin (Mel), which is a known antioxidant and free radical scavenger, could perform the role of a preventive agent against the toxic effects of cadmium (Cd2+) on mortality, fish growth, gonadosomatic index (GSI), luteinizing hormone (LH) secretion, the response to hormonal stimulation of spawning, and also tissue accumulation of Cd in Prussian carp females. These females received melatonin implants and were exposed to 0.4 or 4.0 mg/L of Cd (as CdCl2·2.5H2O) over either a 5- or 3-month period, followed by further 2 months of purification in clear water. Negative changes caused by exposure to cadmium in the water were as follows: higher fish mortality, lower body weight, increased accumulation of cadmium in the brain and ovary, lowered GSI, impaired spontaneous LH secretion during exposure, and impaired LH secretion during stimulation of spawning. All of these effects were observed in the group of fish exposed to 0.4 and/or 4.0 mg Cd/L but did not occur or were less pronounced in the groups exposed to cadmium in the presence of melatonin released from the implants. During depuration, in the group of fish which had been exposed to the highest Cd concentration, we observed a significant improvement in fish survival rate, body growth, inhibition of further cadmium accumulation in tissues, and gradual return of spontaneous LH secretion as well as normalization of the GSI value to the control group levels. In conclusion, these findings indicate that melatonin can be a preventive agent for some toxic effects on fish reproduction induced by environmental cadmium contamination. | Melatonin, Cadmium, LH, Bioaccumulation, Depuration, Prussian carp | 30 | 9915-9927 | 10
اظهر المزيد [+] اقل [-]Chemistry of Sulfur-Contaminated Soil Substrate from a Former Frasch Extraction Method Sulfur Mine Leachate with Various Forms of Litter in a Controlled Experiment
Justyna Likus-Cieślik | Marcin Pietrzykowski | Marcin Chodak
The impact of tree litter on soil chemistry leachate and sulfurous substrates of mine soils from former Jeziórko sulfur mine was investigated. Composites were used: soil substrate (less contaminated at mean 5090 mg kg−1 S or high contaminated at 42,500 mg kg−1 S)thinspace+thinspacebirch or pine litter and control substrate (no litter). The composites were rinsed with distilled water over 12 weeks. In the obtained leachate, pH, EC, dissolved organic carbon, N, Ca, Mg, Al, and S were determined. Physicochemical parameters of the substrates and their basal respiration rate were determined. Rinsing and litter application lowered sulfur concentration in high contamination substrates. Pine litter application decreased EC and increased pH of the low-contaminated substrate. The substrate pH remained at low phytotoxic level (i.e., below 3.0), resulting in the low biological activity of the composites. Birch litter application increased leaching of N and Mg, indicating the possibility of an intensification of soil-forming processes in contaminated sites. | Frasch method, Remediation, Sulfur contamination, Organic matter | 25 | 1-14 | 3
اظهر المزيد [+] اقل [-]Comparative Assessment of response to cadmium in heavy metal-tolerant shrubs cultured in vitro
Alina Wiszniewska | Ewa Hanus-Fajerska | Ewa Muszyńska | Sylwester Smoleń
Two species of Pb-adapted shrubs, Alyssum montanum and Daphne jasminea, were evaluated in vitro for their tolerance to elevated concentrations of cadmium. Shoot cultures were treated with 0.5, 2.5, and 5.0 μM CdCl2 for 16 weeks and analyzed for their organogenic response, biomass accretion, pigment content, and macronutrient status. Cadmium accumulation and its root-to-shoot translocation were also determined. In both species, rooted microplantlets, suitable for acclimatization, were obtained in the presence of Cd applied as selection agent. In A. montanum, low and moderate dose of Cd stimulated multiplication, rooting, and biomass production. Growth tolerance index (GTI) in Cd-treated shoots ranged from 120 to 215%, while in the roots 51–202%. In turn, in Cd-treated D. jasminea proliferation and rooting were inhibited, and GTI for shoots decreased with increasing doses of Cd. However, roots exposed to Cd had higher biomass accretion. Both species accumulated Cd in developed organs, and its content increased with increasing CdCl2 dose. Interestingly, D. jasminea accumulated higher amounts of Cd in the roots than A. montanum and immobilized this metal in the root system. On the contrary, A. montanum translocated some part of accumulated Cd to the shoots, but with low efficiency. In the presence of Cd, A. montanum maintained macronutrient homeostasis and synthesized higher amounts of phytosynthetic pigments in the shoots. D. jasminea accumulated root biomass, immobilized Cd, and restricted its translocation at the expense of nutrient balance. Considering remediation potential, A. montanum could be exploited in phytoextraction, while D. jasminea in phytostabilization of polluted substrate. | Alyssum montanum Daphne jasminea Metallophyte Toxicity Trace metal | 25 | 1-13 | 8, Article:304
اظهر المزيد [+] اقل [-]Factors and mechanisms affecting seasonal changes in the prevalence of microbiological indicators of water quality and nutrient concentrations in waters of the Białka river catchment, Southern Poland
Anna Lenart-Boroń | Anna Wolanin | Łukasz Jelonkiewicz | Mirosław Żelazny
This 3-year study was aimed to understand the factors and mechanisms that cause the temporal changes in the concentration of microbiological indicators of water quality and nutrient concentration in selected sites of the Białka river catchment (southern Poland) situated in direct vicinity of the largest ski station in the region. The analysis comprised 35 sampling campaigns conducted in five sites. Water temperature, pH, and electrical conductivity were measured during sampling, laboratory analyses included determination of the selected nutrients content (NH4, NO3, NO2, PO4); and the number of mesophilic and psychrophilic bacteria, coliforms, fecal coliforms, and Escherichia coli. Based on the cluster analysis, the collected samples were grouped into three to four groups, depending on the most characteristic features. Seasonal variation was evident, showing the predominance of either anthropogenic or natural-environment factors, depending on the considered season. On the other hand, principal component analysis revealed clear effect of various forms of land use in different sites. | Temporal changes, Land use, Coliforms, Escherichia coli, Nutrients | 25 | 1-10 | 9
اظهر المزيد [+] اقل [-]Effect of metal ions on the entomopathogenic nematode Heterorhabditis bacteriophora Poinar (Nematoda:Heterohabditidae) underlaboratory conditions
Magdalena Jaworska | Anna Gorczyca | Jadwiga Sepioł | Piotr Tomasik
Heterorhabditis bacteriophora, entemopathogenic nematodes,metal ion toxicity, nematode infectivity | 0 | 157-166
اظهر المزيد [+] اقل [-]The use of Callitriche cophocarpa Sendtn. for the reclamation of Cr-contaminated freshwater habitat: benefits and limitations
Joanna Augustynowicz | Ewa Sitek | Tomasz Bryniarski | Agnieszka Baran | Beata Ostachowicz | Małgorzata Urbańska-Stopa | Marek Szklarczyk
This work is the first attempt to evaluate suitability of Callitriche cophocarpa Sendtn. (water-starwort) to remove Cr under real-world conditions. Our earlier laboratory-scale studies demonstrated outstanding hyperaccumulation properties of this aquatic higher plant (macrophyte) toward chromium in solution. We introduced C. cophocarpa plants into the watershed with sediments heavily polluted (on average 1400 mg/kg d.w. of Cr) by a tannery. The plants grew vigorously and exhibited no physiological or anatomical disorders. Based on chemical fractionations of bottom sediments, we found low Cr bioavailability. The element was strongly associated with the sediments and could be classified into the following fractions (%): oxidizable III (68.2) > residual IV (28.8) > reducible II (1.6) > exchangeable I (1.4). Despite this, Cr content in plant organs at the contaminated sites was 33 up to 83 times greater than in the control leaf/stem and roots, respectively. Altering redox potential during, i.e., sediment deposition on land may change chemical forms of bound metals in a solid phase, and thus further increase Cr phytoextraction by plants. With this in mind, we concluded that the species, being an outstanding Cr accumulator under laboratory conditions, can be useful in the reclamation of Cr-polluted sediments under controlled, oxidizing conditions. | Callitriche cophocarpa, Chromium, Phytoremediation, Sediments, Tannery effluents, TXRF | 100 | 25510-25522 | 20
اظهر المزيد [+] اقل [-]Forest Humus Type Governs Heavy Metal Accumulation in Specific Organic Matter Fractions
Jarosław Lasota | Ewa Błońska | Stanisław Łyszczarz | Mark Tibbett
Soils have the potential to accumulate heavy metals and the capacity to do so is strongly related the properties of each soil. Soil organic matter is a key factor in the retention, release, and bioavailability of heavy metals, and here we have determined the accumulation of heavy metals in various types of humus in the Rybnik Forest District in southern Poland. In a novel approach, we analyzed relationships between heavy metals within soil organic matter fractions and evaluated the role of organic fractions in mediating metal mobility. Specifically, we tested whether (i) the type of forest humus determines the heavy metal accumulation; (ii) heavy metals accumulation is associated with soil organic matter fractions; and (iii) heavy metals have an inhibitory influence on biochemical properties especially enzymes activity in different humus types. Four types of humus were sampled (mor, moder, moder-mull, mull), physically fractioned, and a number of chemical and biochemical properties were analyzed. Calculated geo-accumulation index (Igeo) and enrichment factor (EF) confirmed soil pollution with Cd and Pb. The type of humus differed in the accumulation of heavy metals, which is associated to the variable concentration of organic matter remaining at each decay class. We found no relationship between enzymatic activity and heavy metals concentration except for a positive correlation between urease activity and nickel concentration. Considering wider evidence, we propose a biogeochemical link between nickel deposition and the production of soil-borne urease in these forest soils. | Enzyme activities, Forest soil, Light and heavy fraction of soil organic matter | 70 | 1-13
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