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Результаты 2901-2910 из 3,208
An endophytic bacterium Acinetobacter calcoaceticus Sasm3-enhanced phytoremediation of nitrate–cadmium compound polluted soil by intercropping Sedum alfredii with oilseed rape Полный текст
2015
Chen, Bao | Ma, Xiaoxiao | Liu, Guiqing | Xu, Xiaomeng | Pan, Fengshan | Zhang, Jie | Tian, Shengke | Feng, Ying | Yang, Xiaoe
Intensive agricultural system with high input of fertilizer results in high agricultural output. However, excessive fertilization in intensive agricultural system has great potential to cause nitrate and heavy metal accumulation in soil, which is adverse to human health. The main objective of the present study was to observe the effects of intercropping and inoculation of endophytic bacterium Acinetobacter calcoaceticus Sasm3 on phytoremediation of combined contaminated soil in oilseed rape (Brassica napus L.). The results showed that with Sasm3 inoculation, the biomass of rape was increased by 10–20 % for shoot, 64 % for root, and 23–29 % for seeds while the nitrate accumulation in rape was decreased by 14 % in root and by 12 % in shoot. The cadmium concentration in rape increased significantly with mono-inoculating treatment, whereas it decreased significantly after intercropping treatment. By denaturing gradient gel electrophoresis (DGGE) and real-time quantitative PCR analysis, the diversity of bacterial community and the number of nirS and nirK gene copies increased significantly with inoculation or/and intercropping treatment. In conclusion, the endophytic bacterium Sasm3-inoculated intercropping system not only improved the efficiency of clearing cadmium from soil without obstructing crop production, but also improved the quality of crop.
Показать больше [+] Меньше [-]Pointing to potential reference areas to assess soil mutagenicity Полный текст
2015
Meyer, D. D. | Da Silva, F. M. R., Jr | Souza, J. W. M. | Pohren, R. S. | Rocha, J. A. V. | Vargas, V. M. F.
Several have been performed to evaluate the mutagenicity of soil samples in urban and industrial areas. The use of uncontaminated reference areas has been an obstacle to the study of environmental mutagenesis. The study aimed to indicate a methodology to define reference areas in studies of environmental contamination based on “Ambient Background Concentration” of metallic elements associated with the Salmonella/microsome assay. We looked at three potential reference areas, two of them close by the industrial sources of contamination (São Jerônimo reference, near the coal-fired power plant, and Triunfo reference, near the wood preservative plant), but not directly influenced by them and an area located inside a protected area (Itapuã reference). We also carried out chemical analyses of some metals to plot the metal profile of these potential reference areas and define basal levels of these metals in the soils. After examining the mutagenicity of the inorganic extracts using strains TA98, TA97a, and TA100, in the presence and absence of S9 mix, we indicated the São Jerônimo reference and the Itapuã reference as two sites that could be used in future studies of mutagenicity of soils in southern Brazil. The association between a mutagenicity bioassay and the “Ambient Background Concentration” seems to be a useful method to indicate the reference areas in studies of contamination by environmental mutagens, where these results were corroborated by canonical correspondence analysis.
Показать больше [+] Меньше [-]Assessment of cadmium (Cd) concentration in arable soil in China Полный текст
2015
Zhang, Xiuying | Chen, Dongmei | Zhong, Taiyang | Zhang, Xiaomin | Cheng, Min | Li, Xinhui
Cadmium (Cd) concentration in arable soil has drawn broad public attention due to its direct effect on Cd concentration in food. However, there have been few studies of surveying Cd accumulation on the national scale in China. This paper collected 486 studies of Cd concentrations in Chinese arable soil. The results showed that the average Cd concentration was 0.27 mg/kg, higher than its background value, indicating that Cd had been introduced into arable soil by human activity. The Cd concentrations in areas of mining and smelting, urban areas, and areas irrigated by wastewater were obviously higher than that in remote areas. Spatially, Cd concentrations were lower in the north than those in the south, and many hotspots existed throughout China due to mining and smelting activities. Most Cd in the arable soil were accumulated from external sources in all investigated provinces except Ningxia Hui Autonomous Region.
Показать больше [+] Меньше [-]Evaluation of zinc accumulation, allocation, and tolerance in Zea mays L. seedlings: implication for zinc phytoextraction Полный текст
2015
Bashmakov, Dmitry I. | Lukatkin, Alexander S. | Anjum, Naser A. | Aḥmad, Iqbāl | Pereira, Eduarda
Evaluation of zinc accumulation, allocation, and tolerance in Zea mays L. seedlings: implication for zinc phytoextraction Полный текст
2015
Bashmakov, Dmitry I. | Lukatkin, Alexander S. | Anjum, Naser A. | Aḥmad, Iqbāl | Pereira, Eduarda
This work investigated the accumulation, allocation, and impact of zinc (Zn; 1.0 μM–10 mM) in maize (Zea mays L.) seedlings under simulated laboratory conditions. Z. mays exhibited no significant change in its habitus (the physical characteristics of plants) up to 10–1000 μM of Zn (vs 5–10 mM Zn). Zn tolerance evaluation, based on the root test, indicated a high tolerance of Z. mays to both low and intermediate (or relatively high) concentrations of Zn, whereas this plant failed to tolerate 10 mM Zn and exhibited a 5-fold decrease in its Zn tolerance. Contingent to Zn treatment levels, Zn hampered the growth of axial organs and brought decreases in the leaf area, water regime, and biomass accumulation. Nevertheless, at elevated levels of Zn (10 mM), Zn²⁺ was stored in the root cytoplasm and inhibited both axial organ growth and water regime. However, accumulation and allocation of Zn in Z. mays roots, studied herein employing X-ray fluorimeter and histochemical methods, were close to Zn accumulator plants. Overall, the study outcomes revealed Zn tolerance of Z. mays, and also implicate its potential role in Zn phytoextraction.
Показать больше [+] Меньше [-]Evaluation of zinc accumulation, allocation, and tolerance in Zea mays L. seedlings: implication for zinc phytoextraction Полный текст
2015 | 1000
Bashmakov, Dmitry I. | Lukatkin, Alexander S. | Anjum, Naser A. | Ahmad, Iqbal | Pereira, Eduarda
This work investigated the accumulation, allocation, and impact of zinc (Zn; 1.0 μM–10 mM) in maize (Zea mays L.) seedlings under simulated laboratory conditions. Z. mays exhibited no significant change in its habitus (the physical characteristics of plants) up to 10–1000 μM of Zn (vs 5–10 mM Zn). Zn tolerance evaluation, based on the root test, indicated a high tolerance of Z. mays to both low and intermediate (or relatively high) concentrations of Zn, whereas this plant failed to tolerate 10 mM Zn and exhibited a 5-fold decrease in its Zn tolerance. Contingent to Zn treatment levels, Zn hampered the growth of axial organs and brought decreases in the leaf area, water regime, and biomass accumulation. Nevertheless, at elevated levels of Zn (10mM), Zn2+ was stored in the root cytoplasm and inhibited both axial organ growth and water regime. However, accumulation and allocation of Zn in Z. mays roots, studied herein employing X-ray fluorimeter and histochemical methods, were close to Zn accumulator plants. Overall, the study outcomes revealed Zn tolerance of Z. mays, and also implicate its potential role in Zn phytoextraction.
Показать больше [+] Меньше [-]Cd accumulation and subcellular distribution in two ecotypes of Kyllinga brevifolia Rottb as affected by Cd treatments Полный текст
2015
Hao, Xiaoqing | Li, Tingxuan | Yu, Haiying | Zhang, Xizhou | Zheng, Zicheng | Chen, Guangdeng | Zhang, Shujin | Zhao, Li | Pu, Yong
The Cadmium (Cd) accumulation capacity and subcellular distribution in the mining ecotype (ME) and non-mining ecotype (NME) of Kyllinga brevifolia Rottb were investigated in pot experiments. The results showed that average Cd contents in shoots of the two ecotypes of K. brevifolia were higher than those in roots, whereas Cd concentrations in roots were greater than those in shoots. Also, shoot Cd contents in NME of K. brevifolia were 1.65–45.45 times greater than those in ME when the plants were grown at 5, 25, 50, and 100 mg Cd kg⁻¹soil. Moreover, Cd contents in the roots in NME were 1.75–45.45 times higher than those in ME. Subcellular distribution of Cd demonstrated that the majority of Cd in the two ecotypes of K. brevifolia was distributed in the cell walls and soluble fraction, and a small percentage of Cd existed in organelle fraction. In addition, proportions of Cd distributed in shoots and roots cell walls of NME were greater than those in ME. It could be assumed that compared with ME, NME of K. brevifolia has better Cd accumulation capacity, and the subcellular distribution of Cd might be one of the mechanisms to explain such phenomena.
Показать больше [+] Меньше [-]Occurrence and potential risk of currently used pesticides in sediments of the Alqueva reservoir (Guadiana Basin) Полный текст
2015
Palma, P. | Köck-Schulmeyer, M. | Alvarenga, P. | Ledo, L. | de Alda, M López | Barceló, D.
The evaluation of sediments, concerning to pesticides, constitutes an important step for the understanding of the principal sources of contamination of the surface water. Hence, the purpose of this study was to evaluate for the first time the occurrence, distribution and risk of pesticides in sediments of the Alqueva reservoir, the largest reservoir in the Europe. For this purpose, the occurrence of 22 pesticides and some of their degradation products was determined in surficial sediments of the Alqueva reservoir. To assess the potential risk on ecosystem, the measured concentrations of pesticides were compared with regulatory and toxicological benchmarks. Of the 22 pesticides analysed, only 8 were detected. Diuron was the pesticide detected in greater concentration, followed by terbuthylazine and chlortoluron. The sediments most polluted by pesticides were from Lucefécit, constituted totally by fine particles (<0.063 mm) and with high values of organic matter, and are located nearby large agricultural fields. The risk assessment allowed us to conclude that the sediments from the Alqueva reservoir presented low risk, concerning to pesticides, for the various communities that integrate the aquatic ecosystems. However, some of the compounds detected present a high potential for bioaccumulation that may lead to their bioamplification in the trophic chain, reaching concentrations higher than their acceptable daily intake, putting, in this way the populations at risk.
Показать больше [+] Меньше [-]Impact of insecticide exposure on the predation activity of the European earwig Forficula auricularia Полный текст
2015
Malagnoux, Laure | Capowiez, Yvan | Rault, Magali
Impact of insecticide exposure on the predation activity of the European earwig Forficula auricularia Полный текст
2015
Malagnoux, Laure | Capowiez, Yvan | Rault, Magali
The European earwig Forficula auricularia is an effective predator in apple orchards. It is therefore crucial to study whether insecticides affect this natural pest control agent. Predation activity, i.e., the number of aphids eaten in 24 h, was determined under laboratory conditions after exposure of fourth-instar nymphs and adult earwigs to widely used insecticides (acetamiprid, chlorpyrifos-ethyl, deltamethrin, and spinosad), which were applied at the normal application rates. Inhibition of acetylcholinesterase and carboxylesterase activities were also measured as indicators of pesticide exposure. Predation activity decreased significantly in nymphs exposed to spinosad (62 %) and chlorpyrifos-ethyl (98 %) compared with controls. A similar response was found for both esterase activities. Spinosad had a stronger effect on AChE (−33 %) whereas chlorpyrifos-ethyl affected CbE activity preferentially (−59 %). Spinosad (20 % of controls), acetamiprid (28 %), and chlorpyrifos-ethyl (66 %) also significantly decreased the predation behavior of adult male but not female (5 to 40 %) earwigs. Adult AChE and CbE activities were also significantly reduced (28 to 67 % of controls) in pesticide-exposed earwigs. Our results suggest that earwigs should be included in the environmental risk assessment framework for authorization of newly marketed plant protection products. Their predation behavior appears to be a sensitive and complementary biomarker.
Показать больше [+] Меньше [-]Impact of insecticide exposure on the predation activity of the European earwig Forficula auricularia Полный текст
2015
Malagnoux, Laure | Capowiez, Yvan | Rault, Magali | Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE) ; Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS) | Abeilles et environnement (AE) ; Institut National de la Recherche Agronomique (INRA) | Unité de recherche Plantes et Systèmes de Culture Horticoles (PSH) ; Institut National de la Recherche Agronomique (INRA) | Provence-Alpes-Cote d'Azur Region (France)
International audience | The European earwig Forficula auricularia is an effective predator in apple orchards. It is therefore crucial to study whether insecticides affect this natural pest control agent. Predation activity, i.e., the number of aphids eaten in 24 h, was determined under laboratory conditions after exposure of fourth-instar nymphs and adult earwigs to widely used insecticides (acetamiprid, chlorpyrifos-ethyl, deltamethrin, and spinosad), which were applied at the normal application rates. Inhibition of acetylcholinesterase and carboxylesterase activities were also measured as indicators of pesticide exposure. Predation activity decreased significantly in nymphs exposed to spinosad (62 %) and chlorpyrifos-ethyl (98 %) compared with controls. A similar response was found for both esterase activities. Spinosad had a stronger effect on AChE (-33 %) whereas chlorpyrifos-ethyl affected CbE activity preferentially (-59 %). Spinosad (20 % of controls), acetamiprid (28 %), and chlorpyrifos-ethyl (66 %) also significantly decreased the predation behavior of adult male but not female (5 to 40 %) earwigs. Adult AChE and CbE activities were also significantly reduced (28 to 67 % of controls) in pesticide-exposed earwigs. Our results suggest that earwigs should be included in the environmental risk assessment framework for authorization of newly marketed plant protection products. Their predation behavior appears to be a sensitive and complementary biomarker.
Показать больше [+] Меньше [-]Determination of natural and synthetic glucocorticoids in effluent of sewage treatment plants using ultrahigh performance liquid chromatography-tandem mass spectrometry Полный текст
2015
Isobe, Tomohiko | Sato, Kentaro | Joon-Woo, Kim | Tanabe, Shinsuke | Suzuki, Go | Nakayama, Kei
A sensitive and comprehensive analytical method for glucocorticoids (GCs) in water samples was developed and applied to effluent of sewage treatment plants (STPs). In the present study, totally 10 natural and synthetic GCs, including cortisol, betamethasone valerate, clobetasol propionate, clobetasone butyrate, difluprednate, betamethasone, dexamethasone, betamethasone dipropionate, methylprednisolone, and prednisolone, were targeted. Analytes were extracted and concentrated using an OASIS HLB solid phase extraction cartridge. Chromatographic separation and quantification were achieved using an ultrahigh performance liquid chromatograph coupled with a tandem mass spectrometer (UHPLC-MS/MS). Method detection limits were 0.05 to 0.89 ng/L, which were 1–2 orders of magnitude more sensitive than in the previous reports. Cortisol was detected in more than half of (27 out of 50) analyzed effluent samples at concentrations in the range of ND-1.36 ng/L, indicating continuous discharge of natural GC via STP effluent. On the other hand, dexamethasone + betamethasone, prednisolone, betamethasone valerate, and clobetasol propionate were detected in 25, 8, 20, and 9 samples among 50 effluent samples, respectively, suggesting not extreme but significant administration of synthetic GCs.
Показать больше [+] Меньше [-]Which coastal and marine environmental contaminants are truly emerging? Полный текст
2015
Maruya, Keith A. | Dodder, Nathan G. | Tang, Chi-Li | Lao, Wenjian | Tsukada, David
To better understand the past and present impact of contaminants of emerging concern (CECs) in coastal and marine ecosystems, archived samples were analyzed for a broad suite of analytes, including pharmaceuticals and personal care products (PPCPs), flame retardants (including PBDEs), perfluorinated compounds (PFCs), and current-use pesticides. Surface sediment, mussels (Mytilus spp.) and sediment core samples collected from the California (USA) coast were obtained from environmental specimen banks. Selected CECs were detected in recent surface sediments, with nonylphenol (4-NP), its mono- and di-ethoxylates (NP1EO and NP2EO), triclocarban, and pyrethroid insecticides in the greatest abundance. Alkylphenols, triclocarban, and triclosan were present in sediment core segments from the 1970s, as well as in Mytilus tissue collected during the 1990s. Increasing concentrations of some CECs (e.g., miconazole, triclosan) were observed in the surface layers (ca. 2007) of a sediment core, in contrast to peak concentrations of 4-NP and triclocarban corresponding to input during the 1970s, and an apparent peak input for PBDEs during the 1990s. These results suggest that chemicals sometimes referred to as “emerging” (e.g., alkylphenols, triclocarban) have been present in the aquatic environment for several decades and are decreasing in concentration, whereas others (e.g., miconazole, triclosan) are increasing.
Показать больше [+] Меньше [-]Lead removal in rats using calcium alginate Полный текст
2015
Savchenko, Olga V. | Sgrebneva, Marina N. | Kiselev, Vladimir I. | Khotimchenko, Yuri S.
Lead (Pb) exposure, even at low levels, causes a variety of health problems. The aims of this study were to investigate the tissue distribution of lead in the bodies of rats, to evaluate lead removal from the internal organs and bones using calcium alginate in doses of 500, 200 and 100 mg/kg per day for 28 days and to assess the impact of calcium alginate on the level of essential elements. Lead (Pb), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu) and zinc (Zn) levels in the blood, hearts, kidneys, livers and femurs of the experimental animals were measured using mass spectrometry with inductively coupled plasma. The results revealed that lead acetate exposure increased the levels of Pb in the blood and organs of the animals and significantly reduced contents of Ca, Mn, Fe, Cu and Zn. Treatment with calcium alginate in dose 500 mg/kg contributed to significant decreases in the amount of lead in the kidney, heart and bones of animals and a slight increase in the content of essential elements in the liver, kidneys and heart, although these changes were not significant. Decreasing of lead was not significant in the internal organs, bones and blood of animals treated with calcium alginate 200 and 100 mg/kg. Consequently, calcium alginate dose of 500 mg/kg more efficiently removes lead accumulated in the body. Calcium alginate does not have negative effect on level of essential elements quite the contrary; reducing the levels of lead, calcium alginate helps normalize imbalances of Ca, Mn, Fe, Cu and Zn. The results of this study suggest that calcium alginate may potentially be useful for the treatment and prevention of heavy metal intoxications.
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