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801.
Sabrine Hatt Boutheina Dridi Lassad Chou Mohamed Ben Kheder Hamadi Bousetta 《环境科学学报(英文版)》2009,21(11):1552-1556
The present work aimed to study the physiological e ects of cadmium (Cd) and copper (Cu) in pea (Pisum sativum). Pea plants were
exposed to increasing doses of cadmium chloride (CdCl2) and copper chloride (CuCl2) for 20 d. The examined parameters, namely root
and shoot lengths, the concentration of photosynthetic pigments and the rate of photosynthesis were a ected by the treatments especially
with high metals concentrations. The analysis of heavy metals accumulation shows that leaves significantly accumulate cadmium for
all the tested concentrations. However, copper was significantly accumulated only with the highest tested dose. This may explain the
higher inhibitory e ects of cadmium on photosynthesis and growth in pea plants. These results are valuable for understanding the
biological consequences of heavy metals contamination particularly in soils devoted to organic agriculture. 相似文献
802.
Ramzi Khiari Sonia Dridi-Dhaouadi Chadlia Aguir Mohamed Farouk Mhenni 《环境科学学报(英文版)》2010,22(10):1539-1543
Sodium carboxymethylcellulose (CMCNa) is an anionic water soluble polyelectrolyte widely used in many industrial sectors
including food, textiles, papers, adhesives, paints, pharmaceuticals, cosmetics and mineral processing. CMCNa was produced by
chemical modification of cellulose, and represents many advantages: natural, renewable, non-toxic and biodegradable. In this study,
di erent kinds of CMCNa, prepared from an agricultural waste date palm rachis, were tested as eco-friendly flocculants for drinking
water treatment and their performances as flocculants in turbidity removal enhancement were assessed. The prepared materials were
characterized by the degree of substitution (DS) and polymerisation (DP). The study of the e ect of some experimental parameters
on the coagulation-flocculation performance, using the prepared materials combined with aluminium sulphate (as coagulant), showed
that the best conditions for turbidity treatment were given for pH 8, coagulant dose 20 mg/L, flocculant concentration of 100 mg/L
and stirring velocity (during the flocculation step) of 30 r/min. Under the optimum conditions, the turbidity removal using CMCNa,
prepared from raw material, was about 95%. A comparison study between the flocculation performance of a commercial anionic
flocculant (A100PWG: polyacrylamide) and that of the prepared CMCNa showed that the performance of the waste-based flocculant
with a DS of 1.17 and a DP of 480 was 10% better than that achieved by the commercial one. 相似文献
803.
Abdul Ghaffar Memon Xiaohong Zhou Yunpeng Xing Ruoyu Wang Lanhua Liu Mohsin Khan Miao He 《Frontiers of Environmental Science & Engineering》2019,13(1):12
804.
Nongrum Ridaphun Kharkongor Mattilang Nongthombam Geetmani Singh Rani Jims World Star Rahman Noimur Kharmawlong George Kupar Nongkhlaw Rishanlang 《Environmental Chemistry Letters》2019,17(3):1325-1331
Environmental Chemistry Letters - The demand for a cleaner environment has led chemists to develop greener protocols, notably by using catalysts. Encapsulation of an active substance on a solid... 相似文献
805.
Asokan S Ali AM Nagarajan R 《Journal of environmental biology / Academy of Environmental Biology, India》2008,29(3):393-396
The nest construction pattern at different stages of nest and variations in the nest microclimate, i.e., temperature and light intensity were assessed in different nests of Baya weaver (Ploceus philippinus) between November 2002 and March 2003 in Nagapattinam and Tiruvarur District of Tamil Nadu, India. The Baya weaver constructed nests in palm (Borassus flabellifer), coconut (Cocos nucifera) and date palm trees (Phoneix psuilla) and majority of the nests were found in the solitary palm. The male bird only involved in the construction and took 18 days to construct a single nest. The birds spent different amount of working hours (in terms of days) for completing various stages of nests viz., wad, ring and helmet stage and in which the 'helmet stage took a maximum of eight days. Furthermore, totally eight active nests were selected and once in a week the variations in the nest microclimate was investigated with reference to atmospheric temperature and light intensity (two active nests) across day throughout the study period. The mean temperature of the nests ranged from 25 degrees C to 29 degrees C and light intensity varied between 25 Lux and 625 Lux. The analysis of variance (ANOVA and ANCOVA) indicated that the nest microclimate varied among the nests in different hr of a day 相似文献
806.
Phytoaccumulation prospects of cadmium and zinc by mycorrhizal plant species growing in industrially polluted soils 总被引:2,自引:0,他引:2
The natural vegetation growing along a wastewater channel was subjected to analyze the uptake of Cadmium (Cd) and Zinc (Zn)
and their subsequent accumulation in aboveground and underground plant parts. Species which were mycorrhizal and growing in
soils receiving industrially contaminated wastewater were collected along with their rhizospheric soil samples. The nearby
uncontaminated control (reference) area was also subjected to sampling on similar pattern for comparison. Both Cd and Zn concentrations
were significantly higher in soils of the study area as compared to the reference site. Five plant species i.e. Desmostachya bipinnata, Dichanthium annulatum, Malvastrum coromandelianum, Saccharum bengalense, and Trifolium alexandrinum were analyzed for metal uptake. The maximum phytoaccumulation of Cd was observed in Desmostachya bipinnata (20.41 μg g−1) and Dichanthium annulatum (15.22 μg g−1) for shoot and root tissues, respectively. However, Malvastrum coromandelianum revealed maximum Zn accumulation for both the shoot and the root tissues (134 and 140 μg g−1, respectively). The examination of cleared and stained roots of the plants from both the areas studied revealed that all
of them were colonized to a lesser or a greater degree by arbuscular mycorrhizal (AM) fungi. The Cd hyperaccumulating grasses
i.e. Desmostachya bipinnata and Dichanthium annulatum, from study area had smaller root:shoot (R/S) ratio as compared to those growing on reference area indicating a negative
pressure of soil metal contamination. The lower R/S ratio in the mycorrhizal roots observed was probably due to increased
AM infection and its mediatory role in soil plant transfer of heavy metals. Furthermore, comparatively lower soil pH values
in the study areas may have played a key role in making the overall phytoavailability of both the metals. Consequently variations
in Cd and Zn tissue concentration among species were observed that also indicate the phytoaccumulation potential of the native
species. 相似文献
807.
Thymol, the main phenolic compound in Thymus vulgaris, has been shown to have various biological effects. The main objective of this study was to investigate the efficacy of thymol on counteracting hexavalent chromium-induced oxidative damage in rat erythrocytes in vitro. The radical scavenging activity of thymol was examined using the 1, 1-diphenyl-2-picrylhydrazyl assay. Erythrocytes resistance to oxidative damage, lipid peroxidation, osmotic pressure, hemolysis as well as morphological alterations were evaluated in the presence of 2.5 µg thymol mL?1 with or without 5 µmol hexavalent chromium mL?1 of the incubation media. Results from the 1,1-diphenyl-2-picrylhydrazyl assay denoted good radical scavenging activity of thymol. Thymol caused a significant increase in superoxide dismutase and catalase activities and reduced glutathione content in erythrocytes intoxicated with hexavalent chromium. In contrast, the presence of thymol resulted in markedly less-elevated malondialdehyde levels, hemolysis, and destabilization of erythrocytes exposed to hexavalent chromium. Microscopically, thymol markedly reduced hexavalent chromium-induced morphological alterations in rat red blood cells. Conclusively, thymol counteracted hexavalent chromium-induced oxidative damage in rat erythrocytes. 相似文献
808.
Mohamed Abd Elaziz Okbah 《Chemistry and Ecology》2013,29(2):97-105
Surface and bottom water samples were collected on a monthly basis from six locations in the Alexandria Western Harbour between April 2002 and March 2003. Total nitrogen, ammonia, nitrite, nitrate, total phosphorus, reactive phosphate and silicate were analysed. The average content of total nitrogen ranged from 81.1 to 65.7?µmol?l?1 in the surface and bottom waters, respectively, while ammonia ranged from 13.77 to 15.79?µmol?l?1 in surface and bottom waters, respectively. Also, the average concentration of nitrite was relatively higher in surface waters than in bottom waters (0.89 and 0.61?µmol?l?1, respectively). The results of this study also indicated a considerable temporal variation in nitrate concentrations which ranged from 1.12 to 13.83?µmol?l?1. Total phosphorus displayed an irregular pattern throughout the year, ranging from 1.9 to 11.8?µmol?l?1 in surface waters and from 1.7 to 9.1?µmol?l?1 in bottom waters. The results of PO4-P analysis showed higher values in surface waters (0.28–2.75?µmol?l?1) than in bottom waters (0.10–1.70?µmol?l?1). The average concentration of silicates was relatively lower in the surface than in the bottom waters (8.97 and 10.1?µmol?l?1, respectively). The analysis of variance (ANOVA) among seasons and sites revealed significant differences for ammonia, total nitrogen and phosphate, while nitrate showed no significant differences among stations. Finally, silicate did not show any significant variance among sites and seasons (ANOVA, P?>?0.05). 相似文献
809.
L. A. Mohamed 《Chemistry and Ecology》2013,29(5):381-386
Presence of Tributyltin (TBT) in Alexandria’s coastal water areas has been demonstrated by measuring concentrations of this compound. The TBT was measured in sediments from three docking areas namely: Western Harbour, Eastern Harbour and Abu Qir Bay. The sediment of those areas has been affected by marine traffic and other industrial activities. This is reflected by the distribution of TBT in the sediments nearby the shipyards in the three docking areas of the region where the average values of 258.6 ηg TBT/g for Western Harbour; 126.4 ηg TBT/g dw for Abu Qir Bay and 42.3 ηg TBT/g dw for the Eastern Harbour were recorded. This fact reflects the effect of industry and marine traffic on the marine environments of the Alexandria region. 相似文献
810.
Julian E. Spallholz PhD L. Mallory Boylan J. David Robertson Linda Smith Mohammad M. Rahman Jason Hook 《毒物与环境化学》2013,95(2):203-210
Arsenic (As) contamination of the available domestic drinking water from shallow aquifers to villagers in Bangladesh often exceeds the newest WHO standard of <10 µg As L?1 and the older Bangladeshi standard of <50 µg As L?1. An estimated 9.2 million shallow tube wells in Bangladesh deliver water to 97% of the rural population, placing an estimated 57 million people at risk for arsenicosis. The contamination of drinking water by As extends to W. Bengal, India and Nepal. The same shallow aquifers used for domestic water are also used to irrigate food crops, particularly rice. Irrigation adds As to soils and increases exposure of the population to additional As via foods consumed. Selenium (Se), an essential trace mineral found in soils, is absorbed by plants, entering the human food chain. It was suggested that a low dietary intake of Se may be contributing to the problem of human arsenicosis in Bangladesh. Dietary Se acts as a natural antidote to As by (1) accelerating As excretion, (2) sequestering As by complexation and (3) as an antioxidant component of the enzyme glutathione peroxidase that may counteract the prooxidant effects of As that contribute to arsenicosis and cancer. Analysis of 70 agricultural soil samples from Bangladesh by fluorimetry, ICP-AES and Neutron Activation Analysis showed the soils analyzed to be high in As (~33 µg g?1) and biologically low in soluble Se (~0.02 µg g?1). A low dietary intake of Se related to low soil content and this mineral in foods may be contributing to human arsenicosis in the Ganges–Brahmaputra delta. 相似文献