Affiner votre recherche
Résultats 4401-4410 de 4,937
Study of the accumulation of contaminants by Cyperus alternifolius, Lemna minor, Eichhornia crassipes, and Canna × generalis in some contaminated aquatic environments Texte intégral
2019
Shirinpur-Valadi, Ali | Hatamzadeh, Abdollah | Sedaghathoor, Shahram
Today, environmental pollution, especially heavy metal pollution, is known as a new and possibly more dangerous pollutant than other environmental ones. For this purpose, the uptake of four aquatic plants in different environments was chosen. In this experiment, four macrophytes, i.e., umbrella palm (Cyperus alternifolius), duckweed (Lemna minor), water hyacinth (Eichhornia crassipes), and canna (Canna × generalis), were studied in five contaminated aquatic environments, i.e., Gohar Rood river, Zarjoob river, Eynak lagoon, Anzali lagoon, and control solution (containing Cd, Cr, Pb, and Zn). The results showed that the highest uptake rates of cadmium, cobalt, vanadium, chromium, zinc, nickel, and lead were observed for duckweed fronds. The highest bioconcentration factor (BCF) of nickel was related to duckweed stem and water hyacinth root, and the highest BCF of cadmium belonged to duckweed fronds and canna root. The highest rate of uptake of cadmium, chromium, zinc, and lead was related to control. The least amount of uptake of several metals by plants was obtained from the water of Gohar Rood and Zarjoob. Generally, based on the results of this study, it can be stated that duckweed is suitable for the uptake of most heavy metals.
Afficher plus [+] Moins [-]Green consumerism: the influence of antioxidant parameters and socio-economic values on Tarhana consumption patterns Texte intégral
2019
Gurbuz, Ismail Bulent | Yıldız, Elif
This study aimed to examine the production and consumption patterns of the tarhana as a green food product and its content in terms of health value in the socio-economic framework by comparing urban and rural households. To be able to assess the tarhana’s health value, the addition of antioxidative parameters was analysed. We obtained the data as a result of a two-part study. The first part of the research included a structured survey conducted between September and December 2015. In the second part, three types of tarhana samples evaluated in terms of their antioxidant capacity and total phenolic content as extractable, hydrolysable, and bioaccessible phenolics to support the claim that homemade tarhana offers higher nutritional potential and healthier content than commercially produced tarhana. Organic and additive-free homemade tarhana samples have great antioxidative potential, also depending on the content and the production pattern. The results of the antioxidant capacity, total phenolic content analyses, and their bioaccessibility revealed that non-fermented homemade tarhana and cranberry-added tarhana stand out, according to production process and content. Our findings showed that participants mostly produced the tarhana at home. In cases where they could not produce it themselves, they supplied it from their family and friends. This result showed us that participants preferred homemade tarhana over industrial tarhana sold in markets. Rural areas mostly consumed tarhana for its economic value. However, tarhana consumption did not decrease in cities. Only the consumption mode and the times have changed.
Afficher plus [+] Moins [-]The ameliorative effect of quercetin on bisphenol A-induced toxicity in mitochondria isolated from rats Texte intégral
2019
Shirani, Maryam | Alizadeh, Saeid | Mahdavinia, Masoud | Dehghani, Mohammad Amin
Recent studies have demonstrated that bisphenol A (BPA) has an adverse or toxic effect on the kidney. This study was designed to evaluate the ability of quercetin (QUER) to prevent BPA-induced mitochondrial dysfunction. Thirty-two healthy adult male Wistar rats were randomly divided into four groups, as follows: control group (olive oil), BPA group (250 mg/kg), BPA þ QUER group (250 mg/kg + 75 mg/kg), and QUER group (75 mg/kg). All treatments were orally administered for 14 days. Kidney mitochondria were isolated by administration of the different centrifugation method. Uric acid and creatinine were considered to be biomarkers of nephrotoxicity. The ameliorative effects of QUER on BPA toxicity were evaluated by determining the glutathione (GSH) content, CAT, the damage to the mitochondrial membrane, the reactive oxygen species (ROS), and lipid peroxidation (LPO). Administration of BPA significantly decreased kidney weight. In the kidney, BPA can deplete GSH content and CAT activity, increase the mitochondrial ROS formation, and enhances LPO and mitochondrial membrane damage. The pretreatment of mitochondria with QUER has the ability to reduce the toxic effects of BPA in isolated mitochondria. These findings suggest a potential role for QUER in protecting mitochondria from oxidative damage in kidney tissue.
Afficher plus [+] Moins [-]Effects of modified sediments from a eutrophic lake in removing phosphorus and inhibiting phosphatase activity Texte intégral
2019
Liu, Wenli | Zhang, Liangjie | Zhang, Jibiao | Liu, Xing | Huang, Wei | Huang, Deying | Zheng, Zheng
Phosphorus is one of the main limiting and strong influencing factors of eutrophication, and phosphorus controlling in lake is of great significance for eutrophication. To do this, sediment materials were taken from Dianchi Lake, a typically eutrophic lake, and modified by hexadecyltrimethylammonium bromide (CTAB) and ZnSO₄ to remove phosphorus and inhibit alkaline phosphatase activity (APA). Results indicated that phosphorus removal efficiencies of sediments modified by CTAB (S-CTAB), ZnSO₄ (S-Zn), and oxidized sediments (OS) were higher than that of the raw sediment (RS). Ability to absorb phosphorus varied, following the order S-Zn>S-CTAB>OS>RS. Sorption was influenced by ionic strength, with the former decreasing with the increase of the latter. Freundlich model well described the sorption isotherm, with an R² ranging from 0.9168 to 0.9958. Furthermore, compared with the raw sediments, the maximum phosphorus sorption capacities of S-Zn and S-CTAB increased by 12.2% and 124.5%, respectively. Results of desorption studies suggest that the desorption rate of S-Zn was from 3.88 to 13.76%, lower than that of other sediment materials. APA was inhibited by S-CTAB and S-Zn at the same time, with inhibition rates from 29.6% and 61.0% when the concentrations of S-CTAB and S-Zn were 10 nmol L⁻¹ and 0.2 nmol L⁻¹, respectively. This study provides new insights into phosphorus removal and phosphatase activity inhibition in water treatment.
Afficher plus [+] Moins [-]Soybean isoflavone ameliorates cognitive impairment, neuroinflammation, and amyloid β accumulation in a rat model of Alzheimer’s disease Texte intégral
2019
Essawy, Amina E. | Abdou, Heba Mohamed | Ibrahim, Hania M. | Bouthahab, Najya M.
Oxidative stress and neuroinflammatory changes appear to be the early events involved in AD’s development and progression. The present study was designed to assess the effect of soybean isoflavone extract (SIFE) against colchicine-induced cognitive dysfunction and oxidative stress in male rats.Fifty adult male Wistar albino rats were divided into five groups: control, ACSF-treated group, soybean isoflavones (SIF)-treated group, colchicine (COL)-treated group, and SIF + COL-treated group. We found that an intracerebroventricular (icv) injection of a single dose of colchicine (7.5 μg/rat bilaterally) resulted in learning deficits in rats subjected to the Morris water maze task associated with marked oxidative damage and decreased acetyl cholinesterase (AChE) activity. In addition, COL caused significant increase in amyloid beta peptide 1-42 (β, amyloid 1-42) interleukin-1β (IL-1β), tumor necrosis factor-α (TNFα), cyclooxygenase-2 (COX-2) and TNF-α genes expression in the brain, and glial fibrillary acidic protein (GFAP) in cortical astrocytes in the brain cortex.Treatment with SIFE (80 mg/kg b.wt) daily for 14 days followed by a single dose of COL significantly reduced the elevated oxidative stress parameters and restored the reduced antioxidant activities. Besides, the administration of SIFE reversed the overproduction of β, amyloid 1-42, pro-inflammatory cytokines, and GFAP in the brain. The obtained results were confirmed by histological observations that clearly indicate a neuroprotective effect of SIF against AD.
Afficher plus [+] Moins [-]Contributions of egg production and egg hatching to the total toxicity of teflubenzuron in Yuukianura szeptyckii (Collembola) in soil toxicity test Texte intégral
2019
Lee, Yun-Sik | Son, Jino | Wee, June | Kim, Yongeun | Kim, Du Yung | Kwon, Jung-Hwan | Cho, Kijong
In the standard ISO soil toxicity test using Collembola, adult survival and juvenile production are the only endpoints that can be attainable. The information on egg production and egg hatching cannot be investigated in the ISO test. To overcome this limitation, in this study, the effects of teflubenzuron on life history parameters of Yuukianura szeptyckii (Collembola) were investigated with a compressed soil test. Teflubenzuron is an insect growth regulator and has a negative effect on egg production, and egg hatching process of arthropods. LC₅₀ decreased with increases in exposure period from 6.97 mg/kg in the third week to 3.60 mg/kg in the fourth week. The EC₅₀ for egg and juvenile production was 0.57 mg/kg and 0.26 mg/kg, respectively. The hatching rate decreased significantly from 46 to 7% as the concentration increased from 0.25 to 1.00 mg/kg, respectively, and the molting frequency was significantly affected only at > 4 mg/kg. The toxic contribution rate (TCR) was defined as the ratio of juvenile production at an exposure concentration compared with the control, and a simple life history model was developed for TCR estimations. At the lower concentrations (< 0.3 mg/kg), the hatching rate reduction was a main contributor to the total toxicity, but the adult mortality and egg production reduction were the main contributors at the higher concentrations (> 2.0 mg/kg). The contribution of egg production reduction remained relatively constant. Since collembolan populations in the soil can be composed of various developmental stages, the differences in the sensitivity to chemicals depending on the developmental stages should be included in the assessment of the toxic impact on soil ecosystems.
Afficher plus [+] Moins [-]Effects of the co-disposal of lignite fly ash and coal mine waste rocks on AMD and leachate quality Texte intégral
2019
Qureshi, Asif | Maurice, Christian | Öhlander, Björn
Lignite fly ash (FA) and waste rocks (WRs) were mixed in three different ratios (1:1, 1:3 and 1:5) and studied to compare the effects of adding FA on acid mine drainage generation from coal mining WRs, leachability of elements and the potential occurrence of the secondary minerals. FA mixed with WRs showed significant differences in pH levels compared to previous research. The 1:1 mixture performed best of all the three mixtures in terms of pH and leachability of elements, mainly due to the higher proportion of FA in the mixture. The pH in the 1:1 mixtures varied between 3.3 and 5.1 compared to other mixtures (2.3–3.5). Iron and SO₄²⁻ leached considerably less from the 1:1 mixture compared to the others, indicating that the oxidation of sulphides was weaker in this mixture. Aluminium leached to a high degree from all mixtures, with concentrations varying from mg L⁻¹ to g L⁻¹. The reason behind this increase is probably the addition of FA which, due to acidic conditions and the composition of the FA, increases the availability of Al. For the same reason, high concentrations of Mn and Zn were also measured. Geochemical modelling indicates that the 1:1 mixture performs better in terms of precipitation of Al³⁺ minerals, whereas Fe³⁺ minerals precipitated more in mixtures containing less FA. These results suggest that, with time, the pores could possibly be filled with these secondary minerals and sulphate salts (followed by a decrease in sulphide oxidation), improving the pore water pH and decreasing the leachability of elements. Since grain size plays a crucial role in the reactivity of sulphides, there is a risk that the results from the leaching tests may have been influenced by crushing and milling of the WR samples.
Afficher plus [+] Moins [-]Prediction of cadmium concentration in brown rice before harvest by hyperspectral remote sensing Texte intégral
2019
Zhou, Weihong | Zhang, Jingjing | Zou, Mengmeng | Liu, Xiaoqing | Du, Xiaolong | Wang, Qian | Liu, Yangyang | Liu, Ying | Li, Jianlong
Cadmium (Cd) contaminated rice has become a global food security issue. Hyperspectral remote sensing can do rapid and nondestructive monitoring of environmental stress in plant. To realize the nondestructive detection of Cd in brown rice before harvest, the leaf spectral reflectance of rice exposed to six different levels of Cd stress was measured during the whole life stages. In addition, the dry weight of rice grain and Cd concentrations in brown rice were measured after harvest. The impact of Cd stress on the quantity and the quality of rice grain and on the leaf reflectance of rice was analyzed, and hyperspectral estimation models for predicting the Cd content in brown rice during three growth stages were established. The results showed that rice plants can impact the quality of the brown rice seriously, even if the impact on the quantity was not significant. All the established models had the capability to estimate Cd concentrations in brown rice (R² > 0.598), and the best performance model, with the R² value of 0.873, was use first derivative spectrum of booting stage as variable. It was concluded that the hyperspectral of rice leaves provides a new insight to predict Cd concentration in brown rice before harvest.
Afficher plus [+] Moins [-]Degradation of tetracyclines in manure-amended soil and their uptake by litchi (Litchi chinensis Sonn.) Texte intégral
2019
Shi, Hui | Bai, Cuihua | Luo, Donglin | Wang, Wei | Zhou, Changmin | Meharg, Andrew A. | Yao, Lixian
The environmental and human health risk posed by veterinary antibiotics is of global concern. Antibiotic uptake by herbal plants has been studied, but little is known about perennial woody fruit crops. Litchi (Litchi chinensis Sonn.), a longevial fruit tree, is routinely fertilized with animal manure and, therefore, may be at risk of antibiotic uptake into its fruits. This study investigated the degradation of chlortetracycline and doxycycline present in manure used to amend orchard soil, and their subsequent assimilation by litchi plant, as affected by manure application rate. The results show that half-lives of chlortetracycline and doxycycline in soil were decreased by increased manure rate, with an average of 27 and 59 days, respectively. Chlortetracycline was readily transported to litchi shoots and increased with the growth of litchi plants. Doxycycline predominantly remained in the roots, and underwent growth dilution in the plants. The two tetracyclines could not be detected in fruits from litchi trees when applied with manures, at various rates, over 2 years. For litchi, chlortetracycline may pose human health risk through manure application, but doxycycline is unlikely to do so. Long-term field experiments are required to monitor antibiotic accumulation in fruits of perennial fruit trees fertilized with animal manure.
Afficher plus [+] Moins [-]Dryland cyanobacterial exopolysaccharides show protection against acid deposition damage Texte intégral
2019
Gao, Xiang | Liu, Li-Tao | Liu, Bin
Soil surface-dwelling cyanobacteria constitute an important part of the dryland ecosystem. The exopolysaccharide (EPS) matrix they establish plays multiple roles in helping cells cope with harsh environments and also improves soil physicochemical properties. Anthropogenic atmospheric nitrogen or sulfur depositions have arisen as an important environmental change in drylands. The acid moisture derived from the depositions will be absorbed by cyanobacterial EPS matrix and thus may pose a threat to cells. In this communication, we evaluated this potential impact in a dryland cyanobacterium, Nostoc flagelliforme, which is a representative polysaccharide-rich species and shows remarkable resistance to desiccation stress. A strong and resilient pH buffering property was found for the EPS matrix, mainly of the polysaccharide’s role, and this could protect the cells from acid damage of pH 4–6, a general acidity range of rainwater in the world. Unlike in acid aquatic environments, terrestrial xeric environments ensure N. flagelliforme unlikely to undertake lasting severe acidification. Thus, protection of the EPS matrix for dryland cyanobacteria would be conducive to sustain their growth and ecological roles in face of atmospheric acid pollution.
Afficher plus [+] Moins [-]