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To detect effects of Cu pollution, the Cu tolerance of soil bacterial communities extracted from several vineyards located in NW Spain was measured. Bacterial community tolerance was estimated by means of the thymidine (TdR) and leucine (Leu) incorporation techniques using either IC(50) values (the log of the metal concentration that reduced incorporation to 50%) or the percentage of activity at one specific Cu concentration (10(-6) mol L(-1)). The tolerance measurements by the TdR incorporation technique were similar to those obtained by the Leu incorporation method, indicating that the two methods were equivalent in terms of suitability for detecting the toxicity of Cu to soil bacterial communities. The two tolerance indices considered (IC50 values and percentage of activity) were closely correlated (r = 0.975, P < 0.001), showing that both were equally good in measuring Cu tolerance of the bacterial community. An increased bacterial community tolerance to Cu, indicating a pollution effect, was observed in vineyard soils with more than 100 mg Cu kg(-1) soil. Thus, the long-term use of Cu in vineyards has a toxic effect on the soil bacterial community, resulting in an increased tolerance. An effect of increased levels of Cu could not be detected when measuring bacterial community activity, pointing to the increased sensitivity to detect toxicity in field studies using tolerance measurements. 相似文献
886.
Soil microbial biomass parameters give useful information about the restoration degree and quality of contaminated soils. These parameters were studied in a field experiment where the effect of two organic amendments on the bioavailability of heavy metals in an agricultural soil and on their accumulation in Beta vulgaris and Beta maritima was assessed. The soil was a calcareous Xeric Torriorthent and the total metal levels were (mg kg(-1)): 2706 Zn, 3235 Pb, and 39 Cu. The treatments were: fresh cow manure, olive husk, and inorganic fertilizer as a control. Two successive crops (B. vulgaris and B. maritima) were grown on the treated and untreated plots. The soil was sampled before each planting and after each harvest over a 15-mo period. Biomass C and N increased in all plots, especially in the organically amended ones. The ratio CO(2)-C/biomass C decreased in olive husk and manure-treated plots, in comparison with the control, and also during the experiment, suggesting a beneficial effect of the organic amendments. In olive husk-treated plots a significant increase in the ratio of biomass C/total organic carbon (TOC) with time was observed. This indicated a reduction of heavy metal stress on the microbial population. The amendments showed, in general, a beneficial effect on soil quality and fertility, while microbial biomass parameters were found to be useful indicators of the evolution of the remediation processes. 相似文献
887.
El-Shafey EI 《Journal of environmental management》2007,84(4):620-627
A carbonaceous sorbent was prepared from peanut shell via sulphuric acid treatment. Se(IV) removal from aqueous solution on the sorbent was studied varying time, pH, Se(IV) concentration, temperature and sorbent status (wet and dry). Se(IV) removal was faster using the wet sorbent than the dry sorbent following a pseudo-first-order model. Se(IV) removal increases at low pH values, and decreases as pH increases until pH 7. Sorption was found to fit the Langmuir equation and sorption capacity for the wet sorbent was higher than that for the dry one. Both sorbents showed an increased selenium sorption by rising the temperature. Redox processes between Se(IV) and the carbon sorbent are involved. Analysis by scanning electron microscope and X-ray powder diffraction for the sorbent after the reaction with acidified Se(IV) confirmed the availability of elemental selenium as particles on the sorbent surface as a result of Se(IV) reduction. Physicochemical tests showed an increase in sorbent acidity, cation exchange capacity (CEC) and surface functionality after the reaction with acidified Se(IV), indicating the oxidation processes occurring on the sorbent surface. Due to its reduction properties, the sorbent seems efficient for Se(IV) removal from aqueous solution. 相似文献
888.
The soils formed on fortifications around the sites of ancient settlements 1500 and 2700 years old were studied in the Endyr archaeological landmarks (West Siberia, central taiga). It was shown that podzolic soils with morphological characteristics identical to those of the background soils were formed during these time periods. An attempt was made to estimate the characteristic times for some chemical characters. The greatest values of this parameter were about 8000 years. 相似文献
889.
Pöllänen R Ikäheimonen TK Klemola S Vartti VP Vesterbacka K Ristonmaa S Honkamaa T Sipilä P Jokelainen I Kosunen A Zilliacus R Kettunen M Hokkanen M 《Journal of environmental radioactivity》2003,64(2-3):133-142
Projectiles suspected to be composed of depleted uranium (DU) were found in Kosovo. Their properties were analysed using alpha and gamma ray spectrometry, mass spectrometry and electron microscopy. They were found to be composed of DU with small amounts of other elements such as Ti. 236U was detected in the penetrators, reflecting the use of reprocessed fuel. No transuranium elements were detected. The typical external dose rate meter is not the best option for mapping the location of penetrators from the ground. Monte Carlo calculations were performed in estimating possible skin doses. Penetrators in long-lasting contact with skin may cause a notable equivalent dose to skin. 相似文献
890.
Clemens Gros Evan Easton-Calabria Meghan Bailey Kadirbyek Dagys Erin Coughlan de Perez Munguntuya Sharavnyambuu Andrew Kruczkiewicz 《Disasters》2022,46(1):95-118
This paper presents evidence relating to a forecast-based cash and non-food item distribution among vulnerable herder households during the 2017–18 dzud (extreme winter) season in Mongolia, and analyses the results of a quasi-experimental study evaluating its impacts. An innovative approach in disaster risk reduction, forecast-based financing (FbF) can have short- and long-term benefits to vulnerable households but remains understudied. The paper contributes information on a multimodal FbF programme offering one-off cash grants and in-kind veterinary kits. The data found significant effects of reduced mortality and increased offspring survival in some types of livestock, and that the timing of FbF assistance is crucial, as reported early assistance correlated to positive outcomes in terms of reduced animal mortality. These findings can be used to design more effective FbF interventions, to understand better the appropriateness of FbF designs, and to use early warnings and early actions to help people prepare and withstand disasters such as dzuds. 相似文献