جستجوی مقالات مرتبط با کلیدواژه « cadmium » در نشریات گروه « منابع طبیعی »

Accurate expression of the solute transport in porous media is critical for evaluating and remediating pollutants in soils and aquifers. An important aspect of the transport of solutes and pollutants is the use of appropriate models to describe their transport behavior. In this study, the concentration of the heavy metal cadmium in the column of undisturbed loamy soil was measured using the miscible displacement experiment. This experiment was repeated in three initial concentrations (50, 100, and 150 mg/L). Then, Cd metal transport was simulated by fractional advection-dispersion equation (FADE). The breakthrough curves obtained from the simulation of FADE and the results of the experiments were fitted and the effect of C0 on its performance was investigated. The order of fractional differentiation (α), dispersion coefficient (D) and retardation factor (R) in all three initial concentrations were estimated and compared using the inverse modeling. The results showed that the FADE model simulates cadmium transport well with r2=0.98 and RMSE=0.05. The comparison of BTSs fitted by the FADE model and the observed laboratory data also confirms this issue. The order of fractional differentiation (α) obtained by the FADE model for Cd was almost the same and equal to 1.7, which indicated the anomalous and non-Fickian transport of cadmium metal in loamy soil columns. It seems that the lack of effect of C0 on α, which is the main parameter of the FADE model, has caused the performance of FADE to have no special trend with the changes of  C0 and can be ignored. The hydrodynamic dispersion coefficient in the transport of Cd was increased by increasing C0 and its process is non-linear and unpredictable and the relationship between R and initial concentration is inverse.

Soil is a natural environment for plant growth and due to its importance, the study of heavy metal distribution for soil contamination monitoring and environmental quality maintaining is necessary. This investigation was performed to study the spatial variability of some heavy metals in some surface soils of the Shazand City. A total of 76 soil surface samples were randomly collected from a depth of 0-30 cm in the study area. After preparation of the samples, some physico-chemical characteristics and the total amount of, lead (Pb), cadmium (Cd), nikel (Ni), zinc (Zn) and copper (Cu) were measured. Mean concentrations of Pb, Cd, Ni, Zn and Cu were 31.20, 54.12, 23.11, 2.05 and 59.36 mgkg-1, respectively. Significant correlations were found between Ni with Cu (r= 0.41, p<0.01) and Zn (r= 0.5, p<0.01). Also, a significant correlation was obsrved between Cu and Zn (r= 0.4, p<0.01). The spatial variability of these variables was examined by variogram models and ordinary kriging. The results of geostatistical analysis showed that the spherical model was the best model for describing the spatial variability of all studied elements. Strong spatial dependence (the ratio of nugget to sill less than 0.25) was obtained for the lead element. According to the standard limits, Pb and Cd showed the highest pollution in rangeland and agricultural land use in the study area, respectively. It’s recommended to increasing soil quality and reduces it’s degradation from pollutants applied proper environmental proceeding.

A greenhouse investigation was performed to examine the influence of salicylic acid and brassinolide on growth and cadmium accumulation of spinach under cadmium stress conditions at Nutrition Research Center, Department of Food Hygiene and Quality Control, Shiraz University of Medical Sciences during 2020 using a factorial as randomized complete block design with three replications. Experimental treatments were including salicylic acid (0, 0.5 and 0.75 mM), and brassinolide (0, 0.5 and 0.75 μM) and cadmium (0, 300 and 600 μM). The results showed that cadmium stress enhanced the concentrations of malondialdehyde (MDA), hydrogen peroxide (H2O2) and electrolyte leakage (EL) as well as reduced the spinach biomass. Under Cd stress conditions, the activities of antioxidant enzymes and the concentrations of proline and carbohydrates increased. Also, application of SA and Br considerably reduced the MDA and H2O2 content and EL, in contrast, elevated the activities of antioxidant enzymes and osmolytes content in Cd-stressed spinach plants, however; the positive effects of SA were high when applied with Br. It was found that the cadmium content in the root was greater than that of spinach leaves. Under 600 μM cadmium stress conditions, application of 0.5 mM salicylic acid, 0.75 mM salicylic acid, 0.50 μM brassinosteroid, 0.75 μM brassinosteroid, 0.5 mM salicylic acid+ 0.5 μl brassinosteroid, 0.5 μM salicylic acid /0 0 mM+ 0.75 μM brasinosteroid, 0.75 μM salicylic acid+ 0.50 μM brasinosteroid and 0.75 μM salicylic acid reduced the cadmium content 12.68, 13.68, 13.93, 22.13, 25.37, 30.09, 30.34 and 45.02% respectively in leaf, as well as 6.53, 10.13, 11.76, 18.30, 26.30, 32.67, 33.34 and 42.81% respectively in root compared to the non-use of these hormones. In conclusion, alleviation of Cd stress by seed priming and foliar application of Br and SA was associated partially with enhanced the activity of the antioxidant system, increase the accumulation of proline and carbohydrates, as well as improve cell membrane stability. Generally, supplementation with Br and SA had a significant effect on reducing the accumulation of cadmium and improving quality and quantity of spinach under Cd-stress.

The aim of this study was to determine the concentrations of heavy metals nickel and cadmium in muscle tissues of Liza klunzingeri in Bushehr seaport during 2017. 30 samples of Liza klunzingeri were caught completely at random from Bushehr seaport by the area local fishermen should be omitted. After biometry based on the MOOPAM procedure. The muscle tissues of the samples were separated and chemical digestion of the samples was done nickel and cadmium accumulation levels in tissues were measured using Graphite furnace atomic absorption instrument (VARIAN AA 100). Based on the results, the mean concentrations of nickel and cadmium in muscle tissues of Liza klunzingeri were 6.638 ± 0.611 and 3.201 ± 0.292 mgkg-1 dry weight, respectively. Findings of this study revealed that nickel and cadmium concentrations in edible tissues (muscle) of Liza klunzingeri captured from Bushehr port are more than the levels permitted within the standards of WHO, FAO, NHMRC and UK(MAFF).

Phytoremediation is the use of plants to remove contaminants from the environment and their safe transfer utilizing the accumulation of heavy metals in plant organs. In this study, in order to compare the ability of plants to absorb cadmium and lead, two tree species of Thuja orientalis and Cupressus arizonica in Alborz industrial town were randomly selected. Thirty trees of each species were selected and different parts of each tree including leaf, stem and root were sampled. Extraction and chemical analysis of all samples were done by Digesdhal device, and then the heavy metals (Lead, Cadmium and Nickel) rate was measured by ICP. The results show that Thoja orientalis can absorb more cadmium and nickel than Cupressus arizonica. Cadmium and nickel rate in the leaves of both species is higher than roots and stems. The comparison of lead absorption rate in organs of two species shows that there was no significant difference between two species, but leaves of two species in comparison with their roots and stems had more lead in their organs. It was concluded that to remove environment contaminant the species selection has to be highly considered.

Cadmium is one of heavy metals which causes high toxicity. In addition, it can be accumulated in plants and make anatomic changes in them. Finding out these changes in industrial woody plants exposed to various extends of cadimum are important, as anatomical changes have direct effect on wood quality and quantity. Therefore, in this research we investigated the effect of different soil cadmium concentrations (0, 30, 60, 120 mg/ kg soil) on anatomical characteristics of leaf in Quercus Castaneifolia such as stomatal density and stomatal pore length. The experiment was performed in completely randomized design and each treatment was replicated 5 times. The results showed that the used cadmium levels had no significant (P<0.05) effect on stomatal length and stomatal density. Therefore, it can be concluded that the concentrations of cadmium used were too low to change the anatomical characteristics of leaves in mentioned seedlings.