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31.
Calcium alginate hydrogel was prepared and used as a biosorbent for the removal of oil from aqueous solutions. Calcium alginate hydrogel was further chemically modified by esterification with maleic anhydride. The changes in the physicochemical properties of maleic anhydride modified calcium alginate were investigated via multiple techniques (FTIR, SEM, BET and DSC/TGA). Adsorption batch experiments were carried out to compare the oil adsorption capacities of native and modified calcium alginates. Adsorption experiments were carried out as a function of solution pH, temperature and ionic strength to determine the optimal conditions for the adsorption of oil. Equilibrium and kinetic studies were conducted for the modified alginate. Results revealed that the maleic anhydride modification of calcium alginate improved its adsorption capacity towards oil. Higher adsorption capacities of modified alginate were attained at lower temperatures (20 °C), higher ionic strengths (1.0 M NaCl) and within the pH range of 5–9. The oil adsorption data obtained for modified alginate could be better described by the first order kinetic model (R2?=?0.981) and the BET equilibrium isotherm (R2?=?0.984). The maximum monolayer adsorption capacity predicted by the BET model for the modified calcium alginate was found to be 143.0 mg/g.  相似文献   
32.
The aim of this work was to investigate for Sarpa salpa the seasonal trend in the food sources, heavy metals bioaccumulation and the oxidative stress in the organs. In addition, the toxicity was assessed by mouse bioassay of extract of the fish's organs collected in autumn, the peak of occurrence of hallucinatory syndrome. The toxicity was further studied for compounds present in epiphyte collected from the sea at the end of spring and in summer that are digested by the S. salpa in these seasons. We observed a higher lipid peroxydation in different tissues of S. salpa compared to the control fish Diplodus annularis. Furthermore, heavy metals accumulation in organs of these fish showed a significant variation between the two species (P?<?0.05). The lethal dose (LD50%) determined for crude ciguatoxin (neurotoxins) extracts of viscera, liver, brain and muscle of S. salpa were as follows: 1.217, 2.195, 14.395, 18.645 g/kg mouse, respectively. We noticed a significant correlation (P?<?0.05) between the total amount of toxic dinoflagellates and the level of TBARS in the liver, the brain and the muscle, this for all seasons and all sizes. Moreover, the cytotoxic effect observed for epiphytes extract confirms the transfer of toxins originating from toxic dinoflagellates, which live as epiphytes on P. oceanica leaves, to the fish by grazing. Our work indicates that, toxic phytoplanktons and heavy metals accumulation are responsible for the increase of oxidative stress in the organs of S. salpa. Hence, the edible part of S. salpa, especially the viscera and liver, can cause a threat to human health, and consumption should, for this reason, be dissuaded.  相似文献   
33.
The present study illustrates an analysis of histological changes; cadmium (Cd), copper (Cu) and zinc (Zn) accumulation; and metallothionein (MT) levels in normal and deformed Mediterranean killifish, Aphanius fasciatus (Pisces, Cyprinodontidae), collected from unpolluted (S1) and polluted areas (S2) in the Gulf of Gabes in Tunisia. Metal determination in water and sediment showed that the concentrations were significantly higher (p?Histopathological investigations revealed greater changes in gills, kidney, liver, and bone tissues of fish from the polluted area than those recorded in fish from the reference area. In comparison to normal fish of the polluted area (S2), tissue alterations were more developed in deformed specimens of this site. A possible relationship between metallic pollution, incidence of spinal deformities, and histological changes in A. fasciatus in the polluted site was discussed.  相似文献   
34.
Rai V  Khatoon S  Bisht SS  Mehrotra S 《Chemosphere》2005,61(11):909-1650
The pollution is increasing in the environment by different kinds of human activities, which results in the accumulation of heavy metals including cadmium in the soil and water and it causes different types of problems to living beings. As the plants are utilized by human being as food and medicine, therefore, it is mandatory to see the effect of metals on plants. In this context, efforts have been made to observe the effect of different concentration of Cadmium (Cd) on Phyllanthus amarus Schum. and Thonn., because Cd is the widespread metal and the plants response to low and high level of exposure is a complex phenomenon. P. amarus is mostly grown as weed in agricultural and waste lands. It is a reputed plant used in Indian indigenous systems of medicine with hepatoprotective, diuretic, stomachic properties and is recently being used for the treatment of hepatitis B. The study revealed that Cd causes significant decrease in fresh and dry weight, length of root and shoot, protein, chlorophyll, carotenoids and sugar and increase in starch content. It is interesting to note that the therapeutically active compounds—phyllanthin and hypophyllanthin, enhanced at certain levels of Cd due to abiotic stress. Besides, the ultramorpholical changes were also observed in stomatal opening and wax deposition on both the surfaces of leaves.  相似文献   
35.
Samples of atmospheric particulate matter obtained from representative areas of the city of Baghdad were collected on glass fiber filters using a high-volume sampler. Atomic absorption techniques were used to analyze the total suspended particulates (TSP) for the following trace metals; Fe, Cu, Zn, Pb, Mn, Cr, Cd, Co, and Hg. Sulfates were measured by turbidemetric method. Ion-selective electrodes was used for chloride analysis. It is concluded that the major components of TSP in the ambient air of Baghdad consist of mineral dust. Pb and Cd gave high enrichment factor values, which implies enrichment of these two metals from anthropogenic sources. High enrichment factors were also obtained for Zn and Cu. It is also concluded that in this arid area, the black smoke reflectance method is not suitable for measuring total suspended matter gravimetrically.  相似文献   
36.
37.
Mussels (Mytilus galloprovincialis), collected from the Bizerta lagoon, were acclimated for four days to various conditions of temperature, salinity, photoperiod and food supply and then exposed to lindane at a concentration of 40 microg l(-1). Catalase activity, which is a biomarker of exposure to an oxidative stress, was measured in the whole soft tissues of control and assay groups. In control mussels, high temperature, high salinity and light duration significantly increased catalase activity whereas this activity decreased when food, composed of freeze-dried, algae was available. When mussels were treated with lindane, catalase activities were higher than in controls. This increase was significant with temperature, salinity and light duration. The food supply did not change catalase activity, which was always higher compared to controls. Oxidative stress was shown in mussels exposed to lindane. The results highlight the need of considering abiotic parameters in biomonitoring studies, and especially when using catalase as a biomarker.  相似文献   
38.
Chromium pollution is a serious environmental problem with few cost-effective remediation strategies available. Crambe abyssinica (a member of Brassicaseae), a non-food, fast growing high biomass crop, is an ideal candidate for phytoremediation of heavy metals contaminated soils. The present study used a PCR-Select Suppression Subtraction Hybridization approach in C.?abyssinica to isolate differentially expressed genes in response to Cr exposure. A total of 72 differentially expressed subtracted cDNAs were sequenced and found to represent 43 genes. The subtracted cDNAs suggest that Cr stress significantly affects pathways related to stress/defense, ion transporters, sulfur assimilation, cell signaling, protein degradation, photosynthesis and cell metabolism. The regulation of these genes in response to Cr exposure was further confirmed by semi-quantitative RT-PCR. Characterization of these differentially expressed genes may enable the engineering of non-food, high-biomass plants, including C.?abyssinica, for phytoremediation of Cr-contaminated soils and sediments.  相似文献   
39.
Water quality and bacterial diversity in the surface water of Rawal Lake was investigated for a period of 8 months to evaluate the pollution load from anthropogenic effects of surrounding areas. Rawal Lake in Islamabad, Pakistan is an artificial reservoir that provides the water needs for the residents of Rawalpindi and Islamabad. Grabbed water samples were collected according to standard protocols from ten different locations of the lake and tributaries keeping in view the recharge points from adjacent areas. Temperature, pH, electrical conductivity, dissolved oxygen, total dissolved solids, hardness, alkalinity, and turbidity of water samples were determined to study the water quality characteristics. The physicochemical parameters showed higher values at the tributaries as compared to the sampling locations within the lake such as values of hardness and alkalinity were 298 and 244 mg/L, respectively, at the tributary of the Nurpur stream. Bacterial strains were isolated by streaking on differential and selective growth media by observing colony morphology and other biochemical tests such as Gram reaction, oxidase, and catalase test. Template DNA was prepared from pure cultivated bacteria and 16S rRNA gene analysis was performed using universal primers for bacteria. Sequencing was performed by using BigDye terminator cycle sequencing kit. Sequences of nearest relative microbial species were identified by using basic local alignment search tool and used as reference sequences for phylogenetic analysis. Phylogenetic trees were inferred using the neighbor-joining method. Sequencing and phylogenetic characterization of microbes showed various phylotypes, of which Firmicutes, Teobacteria, and Proteobacteria were predominant.  相似文献   
40.
Environmental Science and Pollution Research - The objective of the study is to conduct the socio-economic and environmental survey about the feasibility of Saudi Arabia-China-Pakistan Economic...  相似文献   
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