خيارات البحث
النتائج 361 - 370 من 6,548
Wood vinegar and biochar co-application mitigates nitrous oxide and methane emissions from rice paddy soil: A two-year experiment النص الكامل
2020
Feng, Yanfang | Li, Detian | Sun, Haijun | Xue, Lihong | Zhou, Beibei | Yang, Linzhang | Liu, Jiayou | Xing, Baoshan
Both biochar (BC) and wood vinegar (WV) influence the nitrous oxide (N₂O) and methane (CH₄) emissions from agricultural systems. However, the impacts of BC and WV co-application on rice production, N₂O and CH₄ emissions are not well documented. We here conducted a two-year soil columns experiment with four treatments: WV (5 t WV ha⁻¹), BC (7.5 t BC ha⁻¹), WV + BC (5 t WV ha⁻¹ +7.5 t BC ha⁻¹) and a control (no treatment). The results showed that BC and WV + BC produced higher rice grain yield than the control by 14.1–15.9% in 2016 and by 4.1–5.2% in 2017, respectively. While WV increased rice grain yield by 11.2% in 2016, it had no significant influence on yield in 2017. Both WV and BC significantly mitigated N₂O emissions by 22.4–41.8% in 2016 and 22.4–36.9% in 2017, respectively. Interestingly, WV + BC treatment showed the highest N₂O mitigation efficiency, with a 52.9–62.8% mitigations in 2016 and 2017. Furthermore, the co-application of WV and BC significantly mitigated CH₄ emissions by 42.6% in 2016 and 35.3% in 2017, respectively, while applying WV or BC alone had no annually-consistent mitigation effect on CH₄ emissions. Overall, GWPt of rice growth cycle was most significantly suppressed by WV + BC with a 48.7–56.1% reduction, followed by WV and BC with 20.4–28.0% and 19.7–35.7% reductions, respectively. Consequently, the WV + BC treatment had the highest GHGI mitigation effect, averaging with 56.7% over two consecutive rice growth cycles. In conclusion, co-application of WV and BC is recommended for rice cultivation, which can both improve rice yield and minimize GHG emissions.
اظهر المزيد [+] اقل [-]What is the most suitable native bee species from the Neotropical region to be proposed as model-organism for toxicity tests during the larval phase? النص الكامل
2020
Rosa-Fontana, Annelise | Dorigo, Adna Suelen | Galaschi-Teixeira, Juliana Stephanie | Nocelli, Roberta C.F. | Malaspina, Osmar
Currently, Brazil has a full framework for pesticide risk assessment established for Apis mellifera, based on the North American approach. However, the use of Apis mellifera as model-organism as a surrogate for Brazilian native species of stingless bees has been questioned. Assessments on other stages of development than adult individual are essential. Our study aimed to standardize in vitro larval rearing method for the stingless bee species Scaptotrigona postica and Tetragonisca angustula, comparing the results to those obtained for M. scutellaris (previously described), for proposing the most suitable one for using in toxicological larval tests. We used the most efficient method for determining the toxicity of dimethoate on S. postica larvae. We presented the first comparative approach of responses to in vitro larval rearing methods among native bee species from Neotropical region, for use in risk assessment. Our results showed that S. postica was the most suitable native species to be proposed as model-organism. In addition, our results are also very useful for a ring test to validate the method, in accordance to OECD.
اظهر المزيد [+] اقل [-]Remediation of hexavalent chromium in contaminated soil using amorphous iron pyrite: Effect on leachability, bioaccessibility, phytotoxicity and long-term stability النص الكامل
2020
Li, Yunyi | Tian, Xiaoyu | Liang, Jialiang | Chen, Xinlei | Ye, Jiangyu | Liu, Yangsheng | Liu, Yuanyuan | Wei, Yunmei
A large amounts of arable land is facing a high risk of hexavalent chromium (Cr(VI)) pollution, which requires remediation using a low toxic agent. In this study, the remediation effect of amorphous iron pyrite (FeS₂₍ₐₘ₎) on Cr(VI) in Cr(VI)-contaminated soil was evaluated by systematically analyzing the variation of the leachability, bioaccessibility, phytotoxicity, and long-term stability of the remediated soil. The effectiveness of FeS₂₍ₐₘ₎ on the leachability was assessed by alkaline digestion and the toxicity characteristic leaching procedure (TCLP); the effect on the bioaccessibility was evaluated via the physiologically based extraction test (PBET) and the Tessier sequential extraction; the effect on the phytotoxicity was assessed via phytotoxicity bioassay (seed germination experiments) based on rape (Brassica napus L.) and cucumber (Cucumis Sativus L.), and the long-term stability of the Cr(VI)-remediated soil was appraised using column tests with groundwater and acid rain as the influents. The results show that FeS₂₍ₐₘ₎, with a stoichiometry of 4× exhibited a high efficiency in the remediation of Cr(VI) and decreased its leachability and bioaccessibility during the 30-day remediation period. In addition, seed germination rate, accumulation and translocation of Cr, and root and shoot elongation of rape and cucumber of remediated soil are not significantly different from those of clean soil, illustrating that FeS₂₍ₐₘ₎ is suitable for remediating Cr(VI) contaminated arable soil. The stabilization of Cr(VI) in contaminated soil using FeS₂₍ₐₘ₎ was maintained for 1575 days. The long-term effectiveness was further confirmed by the increasing amount of free Fe and Mn in the effluent and the decreasing redox potential. In summary, FeS₂₍ₐₘ₎ has an excellent efficiency for the remediation of Cr(VI), demonstrating it is a very promising alternative for use in the contaminated arable soil.
اظهر المزيد [+] اقل [-]Long-term impact of fertigation with treated sewage effluent on the physical soil quality النص الكامل
2020
Coelho, Anderson Prates | Silva, Matheus Flavio da | Faria, Rogério Teixeira de | Fernandes, Carolina | Dantas, Geffson de Figueiredo | Santos, Gilmar Oliveira
In agriculture, wastewater is used as an alternative source to meet the water and nutritional requirements of plants. However, long-term application of wastewater may degrade soil attributes. This study aimed to evaluate the soil physical quality of Oxisol fertigated with treated sewage effluent (TSE). The experiment was conducted in an area under TSE application for 4 years in Oxisol (625 g kg⁻¹ clay) cultivated with Urochloa brizantha. The treatments consisted of six levels of TSE in irrigation depth, 0%, 11%, 31%, 60%, 87%, and 100%, with four repetitions. Undisturbed and disturbed soils samples were collected in three layers (0.00–0.10 m; 0.10–0.20 m, and 0.20–0.30 m). Aggregation, porosity and water infiltration attributes were evaluated. This work concludes a long-term study on the effects of TSE application on soil properties and on the Urochloa brizantha crop. In other works, carried out in the experimental area of the present study, it was found that TSE fertigation increases the yield and quality of Urochloa brizantha, increases soil fertility and does not lead to soil heavy metal contamination. We note the TSE fertigation does not change the aggregation, porosity, water infiltration rate and organic carbon content in the soil. Irrigation with TSE is recommended in areas with clayey soil and those cultivated with perennial grasses as it does not cause any damage to the physical quality of the soil. Thus, the TSE fertigation can be used on many crops as a source of water and nutrients, reducing the environmental contamination potential.
اظهر المزيد [+] اقل [-]Temporal variation analysis and risk assessment of neonicotinoid residues from tea in China النص الكامل
2020
Li, Shaohua | Ren, Jun | Li, Lifeng | Chen, Rongbing | Li, Jingguang | Zhao, Yunfeng | Chen, Dawei | Wu, Yongning
The extensive use of neonicotinoids (NEOs) has caused the release of wide-ranging of residues to the environment and food, and their potential health risks are now receiving more attention. In this study, three surveys were conducted to obtain the overall profiles of NEO residue levels (seven NEOs and one metabolite) in Chinese tea over a period of seven years. A total of 726 tea samples were tested, and nearly 87% of the samples were found to have detectable NEO residues. The overall average detection frequency of acetamiprid was the highest, reaching 73%. Imidacloprid residues in 4.6% of the samples exceeded the Chinese maximum residue limits, whereas clothianidin and nitenpyram had been detected in Chinese tea samples since 2014. The applications of thiacloprid and thiamethoxam gradually increased, and some tea samples with high residue levels appeared in China. These findings signal the replacement of new and old varieties of NEOs in China. Both long- and short-term cumulative exposures to NEOs were calculated based on optimistic and pessimistic models recommended in the EFSA guidelines. In the three survey periods, the average total imidacloprid-equivalent concentrations were 484.63, 1713.36, and 1148.34 μg/kg, respectively. Combined with the refined point estimates and probabilistic models used in this study, the hazard quotients of NEO residues in tea for Chinese tea consumers were found to be low and within the bounds of safety.
اظهر المزيد [+] اقل [-]Morphological deformation of Daphnia magna embryos caused by prolonged exposure to ibuprofen النص الكامل
2020
Grzesiuk, Malgorzata | Pijanowska, Joanna | Markowska, Magdalena | Bednarska, Anna
The effect of chronic exposure of freshwater cladoceran Daphnia magna to low, environmentally relevant concentrations i.e 4 μgL⁻¹of ibuprofen (a nonsteroidal anti-inflammatory drug) in a laboratory experiment was studied. We observed the key life history traits of first and fifth generation individuals: age and size at first reproduction, number of first clutch eggs and individual growth rate. Moreover, chosen molecular/subcellular markers of experimental animals stress response such as triglyceride content, heat shock proteins (HSP) expression and DNA:RNA ratio were collected. Overall, chronic exposure to ibuprofen had no significant effect on the molecular markers nor on the life history parameters of the Daphnia. It did, however, caused lethal morphological deformities in embryos and juvenile daphnids. Depending on the clonal affiliation, exposure to a low dosage of ibuprofen over five generations resulted in the deformation of ∼3%–∼10% of the first clutch of offspring. Also, up to 90% of females carried at least one deformed embryo. This is the first time that research has revealed such an effect of ibuprofen on D. magna.
اظهر المزيد [+] اقل [-]Co-occurrence and distribution of organophosphate tri- and di-esters in indoor dust from different indoor environments in Guangzhou and their potential human health risk النص الكامل
2020
Hu, Qiongpu | Xu, Liang | Liu, Yi | Zeng, Xiangying | Yu, Zhiqiang
In this study, 45 indoor dust samples and four particulate samples from air-conditioner filters were collected from four different indoor environments in Guangzhou, China, and the concentration and composition of organophosphate tri-esters (OPEs) and organophosphate di-esters (Di-OPs) were determined. Eight of the 10 target OPEs were detected in indoor dust at different detection frequencies (DFs), with tris(2-chloroisopropyl) phosphate and tris(2-chloroethyl) phosphate being the main components. Seven target Di-OPs were detected at different DFs, with diphenyl phosphate being the dominant compound. The total OPEs (∑8 OPEs) and total Di-OPs (∑7 Di-OPs) concentrations varied from 726 to 39,312 ng/g and 68.8–14,766 ng/g, respectively. The ∑8 OPEs concentrations in instrumental houses were significantly higher (p < 0.001) than in three other indoor environments. The varying strengths of the correlation between Di-OPs and their respective parent OPEs was suggestive of their emission sources (e.g., direct application, impurities in OPE formulas, and OPE degradation). The hazard index (HI) values of individual OPEs in residential house were lower than 1, the results suggested a limited human health risk from individual OPEs. However, the total HI value (∑HIs) of OPEs was approximately 1 based on a high exposure scenario and suggested a low risk for toddlers.
اظهر المزيد [+] اقل [-]Influence of long-term biosolid applications on communities of soil fauna and their metal accumulation: A field study النص الكامل
2020
Li, Simin | Zhu, Li | Li, Jin | Ke, Xin | Wu, Longhua | Luo, Yongming | Christie, Peter
Amendment with sewage sludge or biosolids can increase soil fertility but may also transfer biosolid-borne pollutants to the soil and the possible effects on the soil ecosystem are poorly understood, especially long-term effects. A long-term experiment was therefore established to assess the effects of repeated applications of different types of biosolids (fresh domestic, dried domestic and fresh industrial sludges) in field conditions. Nine years of sludge application led to changes in soil chemical and biological properties and generally contributed little to soil nutrient status. However, soil concentrations of potentially toxic elements (PTEs) were elevated by amendment, especially with industrial biosolids. Soil fauna are usually used to decipher the underlying effects of biosolid applications on the soil ecosystem. Here, collembolans (50.9%), nematodes (41.6%) and enchytraeid worms (7.50%) were collected and differentiated into different ecological and trophic groups and their body lengths and PTE concentrations in the body tissues were investigated. The animals showed different responses to the biosolids at population and individual levels. There were substantial changes in epigeic collembolan communities and bacterivorous nematodes increased significantly after biosolid amendment. Biosolid-borne PTEs were major factors and Redundancy (RDA) analysis indicates that collembolan communities were strongly influenced by zinc (Zn). The three groups of soil animals showed similar trends in accumulation of PTEs in the sequence cadmium (Cd) > Zn > copper (Cu), and the bioaccumulation factor (BAF) values of the PTEs were significantly higher in the industrial sludge treatment than in other two treatments with a similar trend of decreasing body length of nematodes. The results indicate that it is potentially risky to use industrial biosolids in the long term, and different species and ecological groups of collembolans and different trophic groups of nematodes should be examined when assessing soil health.
اظهر المزيد [+] اقل [-]Disentangling effects of river inflow and marine diffusion in shaping the planktonic communities in a heavily polluted estuary النص الكامل
2020
Sun, Yi | Li, Hongjun | Yang, Qing | Liu, Yongjian | Fan, Jingfeng | Guo, Hao
Estuarine ecosystems are important in terms of biodiversity processes because there are intense interactions between the river and sea environments. Phytoplankton and zooplankton have been shown to be ecological indicators of the water quality status in estuary ecosystems. Therefore, a comprehensive evaluation of the effects that multiple pressures have on the phytoplankton and zooplankton communities in estuarine ecosystems is essential. In this study, water samples from 29 stations were collected from the Liaohe Estuary over three different seasons, and biotic factors (i.e., phytoplankton and zooplankton) were obtained and compared. The results showed that there were significant temporal and spatial variations in the phytoplankton and zooplankton communities from the Liaohe Estuary. The correlation analyses showed that water temperature was the most important factor regulating the variation in phytoplankton communities, whereas the main driving force for the zooplankton was nutrient concentrations. Large amounts of nutrients entered the estuary in spring and summer due to intensive human activities in the Liaohe River basin. The inflows by the Liaohe River introduced some phytoplankton and zooplankton into the estuary, such as Coscinodicus asteromphalus, Chaetoceros decipiens, and Schmacheria poplesia. The impacts of Liaohe inflows on the estuary region gradually decreased as the distance from the inlet increased and this change was mediated by marine diffusion. The results from this study will improve knowledge about planktonic communities in estuarine ecosystems and provide a theoretical foundation for estuary environmental management.
اظهر المزيد [+] اقل [-]Effects of cadmium, inorganic mercury and methyl-mercury on the physiology and metabolomic profiles of shoots of the macrophyte Elodea nuttallii النص الكامل
2020
Cosio, Claudia | Renault, David
Effects of cadmium, inorganic mercury and methyl-mercury on the physiology and metabolomic profiles of shoots of the macrophyte Elodea nuttallii النص الكامل
2020
Cosio, Claudia | Renault, David
Macrophytes are known to bioaccumulate metals, but a thorough understanding of tolerance strategies and molecular impact of metals in aquatic plants is still lacking. The present study aimed to compare Hg and Cd effects in a representative macrophyte, Elodea nuttallii using physiological endpoints and metabolite profiles in shoots and cytosol.Exposure 24 h to methyl-Hg (30 ng L⁻¹), inorganic Hg (70 ng L⁻¹) and Cd (280 μg L⁻¹) did not affect photosynthesis, or antioxidant enzymes despite the significant accumulation of metals, confirming a sublethal stress level. In shoots, Cd resulted in a higher level of regulation of metabolites than MeHg, while MeHg resulted in the largest number of regulated metabolites and IHg treatment regulated no metabolites significantly. In cytosol, Cd regulated more metabolites than IHg and only arginine, histidine and mannose were reduced by MeHg exposure. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of data suggested that exposure to MeHg resulted in biochemical changes including aminoacyl-tRNA biosynthesis, glycine, serine and threonine metabolism, nitrogen metabolism, arginine and proline metabolism, cyanoamino acid metabolism, while the treatment of Cd stress caused significant variations in aminoacyl-tRNA biosynthesis and branched-chain amino acids pathways. Data supports an impact of MeHg on N homeostasis, while Cd resulted in an osmotic stress-like pattern and IHg had a low impact. Marked differences in the responses to MeHg and IHg exposure were evidenced, supporting different molecular toxicity pathways and main impact of MeHg on non-soluble compartment, while main impact of IHg was on soluble compartment. Metabolomics was used for the first time in this species and proved to be very useful to confirm and complement recent knowledge gained by transcriptomics and proteomics, highlighting the high interest of multi-omics approaches to identify early impact of environmental pollution.
اظهر المزيد [+] اقل [-]Effects of cadmium, inorganic mercury and methyl-mercury on the physiology and metabolomic profiles of shoots of the macrophyte Elodea nuttallii النص الكامل
2020
Cosio, Claudia | Renault, D | Stress Environnementaux et BIOsurveillance des milieux aquatiques (SEBIO) ; Institut National de l'Environnement Industriel et des Risques (INERIS)-Université de Reims Champagne-Ardenne (URCA)-Université Le Havre Normandie (ULH) ; Normandie Université (NU)-Normandie Université (NU)-SFR Condorcet ; Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS) | Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO) ; Université de Rennes (UR)-Institut Ecologie et Environnement - CNRS Ecologie et Environnement (INEE-CNRS) ; Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des sciences de l'environnement de Rennes (OSERen) ; Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Experiments were performed at Geneva University during CC previous position. Authors thank Rebecca Beauvais-Fluck, Floriane Larras, Beatriz Lobo, Nicole Regier and Debora Tanaami for their help in the management of cultures, sampling of water and the preparation of cytosol extracts. The Swiss National Science Foundation (contracts n°205321_138254 and 200020_157173).
International audience | Macrophytes are known to bioaccumulate metals, but a thorough understanding of tolerance strategies and molecular impact of metals in aquatic plants is still lacking. The present study aimed to compare Hg and Cd effects in a representative macrophyte, Elodea nuttallii using physiological endpoints and metabolite profiles in shoots and cytosol. Exposure 24 h to methyl-Hg (30 ng L), inorganic Hg (70 ng L) and Cd (280 μg L) did not affect photosynthesis, or antioxidant enzymes despite the significant accumulation of metals, confirming a sublethal stress level. In shoots, Cd resulted in a higher level of regulation of metabolites than MeHg, while MeHg resulted in the largest number of regulated metabolites and IHg treatment regulated no metabolites significantly. In cytosol, Cd regulated more metabolites than IHg and only arginine, histidine and mannose were reduced by MeHg exposure. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of data suggested that exposure to MeHg resulted in biochemical changes including aminoacyl-tRNA biosynthesis, glycine, serine and threonine metabolism, nitrogen metabolism, arginine and proline metabolism, cyanoamino acid metabolism, while the treatment of Cd stress caused significant variations in aminoacyl-tRNA biosynthesis and branched-chain amino acids pathways. Data supports an impact of MeHg on N homeostasis, while Cd resulted in an osmotic stress-like pattern and IHg had a low impact. Marked differences in the responses to MeHg and IHg exposure were evidenced, supporting different molecular toxicity pathways and main impact of MeHg on non-soluble compartment, while main impact of IHg was on soluble compartment. Metabolomics was used for the first time in this species and proved to be very useful to confirm and complement recent knowledge gained by transcriptomics and proteomics, highlighting the high interest of multi-omics approaches to identify early impact of environmental pollution.
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