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Batch experiments were performed to evaluate the combined effects of ionic activity, pH, and contact time on the cadmium sorption in three different minerals, vermiculite, zeolite, and pumice, commonly employed as substrata in nurseries and recently considered for their potential use in remediation methods. The extent of cadmium sorption was vermiculite>zeolite>pumice, as shown by the Langmuir and Freundlich parameters, and it was highly dependent on mineral characteristics. The percentage of cadmium sorption in zeolite and vermiculite did not depend on cadmium concentration, while in pumice this percentage was positively correlated to the initial cadmium concentration. At low cadmium concentrations (30-120 microM), the metal sorbed on zeolite was mainly present in the nonexchangeable form (70%) at levels much higher than those found for vermiculite and pumice. The primary variable responsible for determination of cadmium mobility in these minerals was confirmed to be pH. The ionic concentrations of Hoagland nutrient solution were significantly modified by both pH and mineral composition, while the presence of cadmium caused no changes. With vermiculite and zeolite, the time-course of cadmium sorption was related to mineral composition to a greater extent than to cadmium concentration. While with pumice, the percentage of cadmium sorbed after 6 weeks was lower than with the other two minerals, and it was inversely correlated to the initial cadmium concentration. 相似文献
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Rosaria Acquaviva Luca Vanella Valeria Sorrenti Rosa Santangelo Liliana Iauk Alessandra Russo Francesca Savoca Ignazio Barbagallo Claudia Di Giacomo 《Environmental science and pollution research international》2012,19(9):3850-3858
Exposure to chemical pollution can cause significant damage to plants by imposing conditions of oxidative stress. Plants combat oxidative stress by inducing antioxidant metabolites, enzymatic scavengers of activated oxygen and heat shock proteins. The accumulation of these proteins, in particular heat shock protein 70 and heme oxygenase, is correlated with the acquisition of thermal and chemical adaptations and protection against oxidative stress. In this study, we used Pinus pinaster Ait. collected in the areas of Priolo and Aci Castello representing sites with elevated pollution and reference conditions, respectively. The presence of heavy metals and the levels of markers of oxidative stress (lipid hydroperoxide levels, thiol groups, superoxide dismutase activity and expression of heat shock protein 70, heme oxygenase and superoxide dismutase) were evaluated, and we measured in field-collected needles the response to environmental pollution. P. pinaster Ait. collected from a site characterized by industrial pollution including heavy metals had elevated stress response as indicated by significantly elevated lipid hydroperoxide levels and decreased thiol groups. In particular, we observed that following a chronic chemical exposure, P. pinaster Ait. showed significantly increased expression of heat shock protein 70, heme oxygenase and superoxide dismutase. This increased expression may have protective effects against oxidative stress and represents an adaptative cellular defence mechanism. These results suggest that evaluation of heme oxygenase, heat shock protein 70 and superoxide dismutase expression in P. pinaster Ait. could represent a useful tool for monitoring environmental contamination of a region and to better understand mechanisms involved in plant defence and stress tolerance. 相似文献
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Iesce MR della Greca M Cermolal F Rubino M Isidori M Pascarella L 《Environmental science and pollution research international》2006,13(2):105-109
Background N-methylcarbamate insecticides are widely used chemicals for crop protection. This study examines the hydrolytic and photolytic
cleavage of benfuracarb, carbosulfan and carbofuran under natural conditions. Their toxicity and that of the corresponding
main degradation products toward aquatic organisms were evaluated.
Methods Suspensions of benfuracarb, carbosulfan and carbofuran in water were exposed to sunlight, with one set of dark controls,
for 6 days, and analyzed by 1H-NMR and HPLC. Acute toxicity tests were performed on Brachionus calyciflorus, Daphnia magna,
and Thamnocefalus platyurus. Chronic tests were performed on Pseudokirchneriella subcapitata, and Ceriodaphnia dubia.
Results and Discussion Under sunlight irradiation, benfuracarb and carbosulfan gave off carbofuran and carbofuran-phenol, while only carbofuran
was detected in the dark experiments. The latter was degraded to phenol by exposure to sunlight. Effects of pH, humic acid
and KNO3 were evaluated by kinetics on dilute solutions in the dark and by UV irradiation, which evidenced the lability of
the pesticide at pH 9. All three pesticides and phenol exhibited acute and higher chronic toxicity towards the aquatic organisms
tested.
Conclusion Investigation on the hydrolysis and photolysis of benfuracarb and carbosulfan under natural conditions provides evidence
concerning the selective decay to carbofuran and/or phenol. Carbofuran is found to be more persistent and toxic.
Recommendations and Outlook The decay of benfuracarb and carbosulfan to carbofuran and the relative stability of this latter pesticide account for many
papers that report the detection of carbofuran in water, fruits and vegetables. 相似文献
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Seasonal Fluctuations in the Nutritional Value of Particulate Organic Matter in A Lagoon 总被引:2,自引:0,他引:2
Water samples were collected on a fortnightly basis in the lagoon of S. Gilla (Sardinia, Mediterranean Sea) in order to study seasonal nutritional fluctuations of particulate organic matter. the lagoon is characterized by high quantities of suspended matter throughout the year. Thermohaline conditions had no effect on particulate matter quantity and composition, but the quantity as well as quality of suspended particles was drastically affected by the wind, the major effecter of sediment resuspension. As a result of sediment resuspension, seston was always richer in inorganic fraction. However, throughout the year of investigation, most particulate organic carbon was quite appealing for filter feeding communities, although the best POM quality was available during phytoplankton blooming. the phytoplankton pool of suspended matter was just a small fraction of the bulk, accounting for only 13% on average of particulate organic carbon. in terms of energy available in the seston, the highest amount was stored in organic matter heterotrophic fraction, whilst the smallest was to be found in living phytoplankton. 相似文献
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Chiara Guarisco Giovanni Palmisano Giuseppe Calogero Rosaria Ciriminna Gaetano Di Marco Vittorio Loddo Mario Pagliaro Francesco Parrino 《Environmental science and pollution research international》2014,21(19):11135-11141
Sensitized P25 TiO2 was prepared by wet impregnation with a home-prepared perylene dye, i.e., N,N′-bis(2-(1-piperazino)ethyl)-3,4,9,10-perylene-tetracarboxylic acid diimide dichloride (PZPER). Energy levels of PZPER were found to be compatible with those of TiO2 allowing fast electron transfer. The obtained catalyst has been characterized and used in the gas-phase partial oxidation of aliphatic primary and secondary alcohols, i.e., methanol, ethanol, and 2-propanol. The reaction was carried out under cut-off (λ?>?400 nm) simulated solar radiation in O2 atmosphere. The perylene derivative allowed a good absorbance of visible radiation thanks to its low optical energy gap (2.6 eV) which was evaluated by cyclic voltammetry. The optimal organic sensitizing amount was found to be 5.6 % w/w in terms of yield in carbonyl derivatives. Moreover, no change in reactivity/selectivity was observed after 10-h irradiation thus confirming the catalyst stability. Yields into formaldehyde, acetaldehyde, and acetone were 67, 70, and 96 %, respectively. No significant amounts of organic byproducts were detected but for methanol oxidation, whereas a minor amount of the substrate degraded to CO2. 相似文献