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Chromium toxicity in plants 总被引:56,自引:0,他引:56
Due to its wide industrial use, chromium is considered a serious environmental pollutant. Contamination of soil and water by chromium (Cr) is of recent concern. Toxicity of Cr to plants depends on its valence state: Cr(VI) is highly toxic and mobile whereas Cr(III) is less toxic. Since plants lack a specific transport system for Cr, it is taken up by carriers of essential ions such as sulfate or iron. Toxic effects of Cr on plant growth and development include alterations in the germination process as well as in the growth of roots, stems and leaves, which may affect total dry matter production and yield. Cr also causes deleterious effects on plant physiological processes such as photosynthesis, water relations and mineral nutrition. Metabolic alterations by Cr exposure have also been described in plants either by a direct effect on enzymes or other metabolites or by its ability to generate reactive oxygen species which may cause oxidative stress. The potential of plants with the capacity to accumulate or to stabilize Cr compounds for bioremediation of Cr contamination has gained interest in recent years. 相似文献
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Rachel L. McDaniel Michelle L. Soupir Ross B. Tuttle Amy E. Cervantes 《Journal of the American Water Resources Association》2013,49(2):319-327
Abstract: Water‐quality standards have been placed on fecal indicator organisms such as Escherichia coli in an attempt to limit the concentrations in water bodies. Cattle can be a significant source of bacteria to water systems, particularly when they are allowed direct access to streams. A flume study was conducted to quantify the effect and understand the transport of E. coli from directly deposited cattle manure. Five steady‐state flows, ranging from 0.00683 to 0.0176 m3/s, were studied and loads from a single cowpie exceeded the U.S. Environmental Protection Agency’s recommended water‐quality standards (235 CFU/100 ml) at each flow over the hour study period. Average E. coli concentrations ranged from 102 to 105 CFU/100 ml over the hour sampling period for all flows. High spatial variations in E. coli concentrations were often seen at each sampling time, with higher concentrations typically at the bottom of the flume. E. coli resuspension was initially greater at 0.5 min after deposition, for the lowest flow (105 CFU/m2/s); however, resuspension rates became similar over time, on the order of 103 CFU/m2/s. This study demonstrates that the concentrations of E. coli can vary over the water column, and therefore grab samples may inaccurately measure bacteria concentrations and loads in streams. In addition, resuspension rates were often high, so the incorporation of this process into water‐quality models is important for bacteria prediction. 相似文献
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Cervantes FJ Enríquez JE Galindo-Petatán E Arvayo H Razo-Flores E Field JA 《Chemosphere》2007,68(6):1082-1089
The effect of high concentrations of sulphate on the reductive decolourisation of different azo dyes by anaerobic sludge was studied in batch cultures. Sludge cultures were pre-incubated under sulphate-reducing conditions prior addition of dyes. Little or no effects of sulphate (5-10 g sulphate l(-1)) on the rate of decolourisation of Reactive Orange 14 (RO14), Direct Blue 53 (DB53) and Direct Blue 71 (DB71) were observed when no external redox mediator was provided. However, an increase in sulphate concentration, in the presence of riboflavin (20 microM), enhanced the decolourisation of all dyes. The first-rate constant of decolourisation (k) was increased up to 2-, 3.6- and 2-fold for RO14, DB53 and DB71, respectively, by supplying high sulphate concentrations, compared to the controls lacking sulphate, in the presence of the redox mediator. Sulphate reduction did not take place during the course of azo reductions, but was only evident before dye addition and after complete decolourisation, suggesting azo dyes reduction out-competed sulphate reduction for the available reducing equivalents. The experimental data suggest that reduction of azo dyes by riboflavin, which had been reduced by biogenic sulphide, was the major mechanism implicated during decolourisations, which was corroborated by abiotic incubations. Riboflavin greatly accelerated the abiotic reduction of RO14, so that the k value was increased up to 44-fold compared to the control lacking riboflavin. 相似文献
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Mendoza-Cantú A Heydrich SC Cervantes IS Orozco OO 《Journal of environmental management》2011,92(7):1706-1713
The oil industry is one of the main productive activities in Mexico and has a huge infrastructure, including a wide pipeline network that crosses urban, industrial, agricultural and natural areas. The threat of crude oil spills is greatest in those regions with a high concentration of oil extraction and refining activities, as in the case of the Coatzacoalcos and Tonalá Rivers Low Basin. This study ranked the geosystems of the basin in terms of vulnerability to pipeline crude oil spills. Very high vulnerability (level I) was assigned to the water bodies (lakes and rivers) and their margins of influence, including surfaces that flood during normal hydraulic load. High vulnerability areas (level II) comprised surfaces that can flood during extraordinary hydraulic load related with extreme hydrometeorological events. The remaining three vulnerability levels were defined for areas with low or negligible flooding potential, these were ranked according to physical (slope, relief and permeability), biological (richness, singularity and integrity) and socio-economic (social marginalization index and economic activities index) conditions. These results are presented on a map for better visualization and interpretation. This study will be useful to establish preventive and effective emergency management actions in order to reduce remediation costs and adverse effects on wild species. It also can help local and national authorities, oil industry and civil protection corps to better protect ecosystems, natural resources and human activities and goods. 相似文献
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Optimizing the APC residue washing process to minimize the release of chloride and heavy metals 总被引:1,自引:0,他引:1
Chimenos JM Fernández AI Cervantes A Miralles L Fernández MA Espiell F 《Waste management (New York, N.Y.)》2005,25(7):686-693
An optimization of the air pollution control (APC) residue washing process was carried out to minimize the release of chloride and heavy metals. Taking into account economic parameters such as the consumption of water and reaction time, the best relation found was a S/L ratio of 1/3 during 1 h. At a laboratory scale and according to the values obtained for chloride and heavy metals, the APC residue is classified as non-special according to Catalonian Regulations (Spain). Moreover, the pH of the solution, when MgSO(4) is added during the washing process, may be controlled by the formation of gypsum. In these conditions, the concentration of heavy metals will decrease as a consequence of the formation of their respective insoluble hydroxides. Therefore, the counter-current batch washing process with the addition of small amounts of MgSO(4) is revealed as an economically feasible treatment of the APC residue. This washed residue is ready to be used as secondary material or to be landfilled safely. 相似文献
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Impacts of intensive agricultural irrigation and livestock farming on a semi-arid Mediterranean catchment 总被引:1,自引:0,他引:1
Emi Martín-Queller David Moreno-Mateos César Pedrocchi Juan Cervantes Gonzalo Martínez 《Environmental monitoring and assessment》2010,167(1-4):423-435
Irrigation return flows (IRF) are a major contributor of non-point source pollution to surface and groundwater. We evaluated the effects of irrigation on stream hydrochemistry in a Mediterranean semi-arid catchment (Flumen River, NE Spain). The Flumen River was separated into two zones based on the intensity of irrigation activities in the watershed. General linear models were used to compare the two zones. Relevant covariables (urban sewage, pig farming, and gypsum deposits in the basin) were quantified with the help of geographic information system techniques, accompanied by ground-truthing. High variability of the water quality parameters and temporal dynamics caused by irrigation were used to distinguish the two river reaches. Urban activity and livestock farming had a significant effect on water chemistry. An increase in the concentration of salts (240–541 μS·cm???1 more in winter) and nitrate (average concentrations increased from 8.5 to 20.8 mg·l???1 during irrigation months) was associated with a higher level of IRF. Those river reaches more strongly influenced by urban areas tended to have higher phosphorus (0.19–0.42 mg·l???1 more in winter) concentrations. These results support earlier research about the significant consequences to water quality of both urban expansion and intensive agricultural production in arid and semi-arid regions. Data also indicate that salinization of soils, subsoils, surface water, and groundwater can be an unwelcome result of the application of pig manure for fertilization (increase in sodium concentration in 77.9 to 138.6 mg·l???1). 相似文献
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YOAN PAILLET LAURENT BERGÈS JOAKIM HJÄLTÉN PÉTER ÓDOR CATHERINE AVON MARKUS BERNHARDT‐RÖMERMANN RIENK‐JAN BIJLSMA LUC DE BRUYN MARC FUHR ULF GRANDIN ROBERT KANKA LARS LUNDIN SANDRA LUQUE TIBOR MAGURA SILVIA MATESANZ ILONA MÉSZÁROS M.‐TERESA SEBASTIÀ WOLFGANG SCHMIDT TIBOR STANDOVÁR BÉLA TÓTHMÉRÉSZ ANNELI UOTILA FERNANDO VALLADARES KAI VELLAK RISTO VIRTANEN 《Conservation biology》2010,24(4):1157-1160
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Tovar-Sánchez E Cervantes LT Martínez C Rojas E Valverde M Ortiz-Hernández ML Mussali-Galante P 《Environmental science and pollution research international》2012,19(5):1677-1686