Showing 9 results for Khodaverdiloo
H. Khodaverdiloo, M. Homaee,
Volume 11, Issue 42 (winter 2008)
Abstract
Phytoremediation is a new technology that employs plants to remediate contaminated soils. This method compared to those that involve the use of large scale energy consuming equipments is an inexpensive method. Phytoremediation models are useful tools to further understanding the governing processes and also to manage the contaminated soils. A thorough literature review indicates that very few models have been developed for phytoremediation due to the complexity of the phenomena. The objective of this study was to develop a simple model for phytoremediation of lead and cadmium. A new formulation of phytoremediation was established based on soil and plant responses to heavy metal pollution. A large quantity of a sandy loam soil was thoroughly mixed to ensure homogeneous different concentration levels by lead and cadmium. These contaminated soils were transferred to some plastic pots. Land Cress (Barbarea verna) and Spinach (Spinacia oleracea L.) seeds were germinated in pots containing 8 kg of contaminated soil. Plants were harvested at five time intervals. The concentrations of Pb and Cd in the plant and soil samples were digested by wet oxidation and 4 M Nitric acid digestion methods, respectively, and were determined by flame and graphite furnace atomic absorption spectrometry methods. Proposed models then were calibrated using the collected data and validated quantitatively. The results indicated that the soil adsorption isotherms followed a linear form for both Pb and Cd concentrations. The results also indicated that the phytoremediation rate of Pb by Land Cress and Spinach are first-order function of Pb concentration in soil. In contrast, a zero-order function of soil Cd contaminations was obtained. Combining these two results of soil and plant responses to Pb and Cd pollution, a simple model with reasonable performance was derived to predict the time needed for remediation of soil Pb (R2 > 0.98). However, in the case of Cd, the derived models appeared to be useful to make only some overall estimations of the remediation (R2≈0.70).
M Davari, M Homaee, H Khodaverdiloo ,
Volume 14, Issue 52 (sumer 2010)
Abstract
Phytoremediation is a new, in-situ and emerging remediation technology for contaminated soils. This technology, compared to other methods, is a sustainable, natural, relatively cheap and applicable to large scale area. Modeling phytoremediation provides quantitative insight for the governing process as well as for managers to assess the remediated sites. The objective of this study was to introduce a macroscopic phytoremediation model for Ni and Cd- polluted soils. The proposed model assumes that relative transpiration reduction function can resemble total soilNi and Cd concentrations. Combining the related functions of soil and plant responses to soil Ni and Cd concentrations, the phytoremediation rate of Ni and Cd was predicted. In order to test the proposed model, large quantities of soil were thoroughly polluted with Ni and Cd. Upland Cress (Lepidum sativum) and Ornamental Kale (Brassica olerace var. Viridis) seeds were then germinated in the contaminated soils. The experimental pots were irrigated with fresh water to reach field capacity. Upland Cress and Ornamental Kale were harvested three and four times, respectively. At each harvest, relative transpiration, Ni and Cd contents of soil samples and plants were measured. Comparison of the maximum error, root mean square error, coefficient of determination, modeling efficiency and coefficient of residual mass indicated that the non-threshold non-linear model provide high efficiency to predict relative transpiration for Upland Cress and Ornamental Kale, respectively. The results also indicated that the proposed macroscopic model can well predict the phytoemediation rate of the Ni and Cd by Upland Cress (R2>0.83) and Ni by Ornamental Kale (R2=0.78).
M. Rahmanian, H. Khodaverdiloo, M. H. Rasouli Sadaghiani, Y. Rezaie. Danesh, M. Barin,
Volume 15, Issue 58 (winter 2012)
Abstract
Arbuscular mycorrhizae (AM) and Plant Growth Promoting Rhizobacteria (PGPR) associations are integral and functioning parts of plant roots. These associations have a basic role in root uptake efficiency as well as improvement of plant growth in degraded environments including heavy metals contaminated soils. This study was conducted to evaluate the effects of heavy metal-resistant soil microbe's inoculation on bio-availability of Pb and Cd in soil, plant growth as well as metal uptake by Millet (Pennisetum glaucum), Couch grass (Triticum repens) and wild alfalfa (Medicago sativa). A soil sample was treated by different levels of Pb and Cd (soil 1). Native microbial inoculums were obtained from alfalfa rhizosphere soils adjacent to Pb and Cd mines in Zanjan region (soil 2), then added with weight ratio of 1:5 (w/w) to soil 1. Host plants including millet, couch grass, and alfalfa were grown in pots and kept in greenhouse conditions. At the end of growing period, shoot dry matter and Pb and Cd concentrations in plant and soil were measured. Results indicated that plants yield and Pb uptake were significantly higher in non-inoculated treatments (p ≤ 0.05). However, Cd uptake by plants was greater in inoculated treatments (p ≤ 0.05). Couch grass showed the most accumulation potential of Cd and Pb among the studied plants.
R. Hamzenejad Taghlidabad, H. Khodaverdiloo, S. Rezapour, Sh. Manafi,
Volume 16, Issue 60 (Summer 2012)
Abstract
Soil contamination with heavy metals, including Cd and Pb, is of serious concern. The aim of this study was to investigate the efficiency of Atriplex verucifera, Salicornia europaea and Chenopodium album for simultaneous remediation of soil exchangeable sodium percentage and Cd and Pb contamination in two soils with different properties. Two soils, including a saline-sodic-calcareous (S1) and calcareous (S2) soil, were selected. Different concentrations of Pb and Cd were then added to the soils. The contaminated soils were incubated under a wetting-drying cycle for nearly seven months. The plants, seeds were grown in pots containing different treatments of polluted soils and in control treatment (no Cd and Pb contaminations). The plant yields and concentrations of Pb, Cd and Na in the soil and plant samples were measured. A considerable accumulation of soil Cd by Salicornia and Pb accumulation by Atriplex and Salicornia was observed under unsuitable conditions of the saline-sodic soil, whereas Atriplex and Chenopodium had high capability for Cd in the soil S2. Also these plants caused the reduction of ESP in soil S1. The results revealed that these plants could be used for remediation of Pb and Cd contaminated soils. In this study, Salicornia with lower rate of yield reduction had the highest tolerance to Cd-stress. Understanding the complex plant and soil (salinity-sodicity and soil metal concentration) factors controlling the metals concentrations in the plants will help to design phytoextraction technology for arid, salt-affected regions.
Sh. Ghorbani Dashtaki, S. Dehghani Baniani, H. Khodaverdiloo, J. Mohammadi, B. Khalilmoghaddam,
Volume 16, Issue 60 (Summer 2012)
Abstract
Saturated hydraulic conductivity (Kfs) and macroscopic capillary length of soil pores are important hydraulic properties for water flow and solute transport modeling. Measuring these parameters is tedious, time consuming and expensive. One way is using indirect methods such as Pedotransfer functions (PTFs). The objective of this research was to develop some PTFs for estimating saturated hydraulic conductivity and inverse of macroscopic capillary length parameters (*). Therefore, the coefficients, Kfs and * from 60 points of Azadegan plain in Shahrekord were measured using single ring and multiple constant head method. Also, some of the readily available soil parameters from the two first pedogenic layers of the soils were obtained. Then, the desired PTFs were developed using stepwise multiple linear regression. The accuracy and reliability of the derived PTFs were evaluated using root mean square error (RMSE), mean error (ME), relative error (RE) and Pearson correlation coefficient (r). The highest correlation coefficients of 0.92 and 0.72 were found between Kfs-bulk density and *-bulk density, respectively. There was no significant correlation between soil particle size distribution and Kfs and *. This can be related to the fact that most of the soil samples were similar in texture and macro pores. The most efficient PTFs in predicting Kfs and * could explain 85 and 66 percent of the variability of these parameters, respectively. All the derived PTFs underestimated the Kfs and * parameters.
H. Mirshekali, H. Hadi, H. Khodaverdiloo, R. Amirnia,
Volume 18, Issue 67 (Spring 2014)
Abstract
Heavy metals contamination of soil and plants has very important and vital role in relation to health and life of human
and other organisms. The aim of this study was to assess the efficiency of sorghum (Sorghum bicolor) and sommon
lambsquarter (Chenopodium album) in phytoremediation of Zn from soil. Efficiency of 0.01M CaCl2, 0.1M NaNO3, and
1M NH4NO3 for extraction of “bioavailable fraction of soil Zn was also compared. Correlation between the Zn
concentrations extracted by these methods and plants response (relative yield and shoot Zn concentration) to soil Zn
contamination was then evaluated. For this purpose, a calcareous soil sample was contaminated with different
concentrations of Zn. Sorghum and common lambsquarter, were grown in pots containing the contaminated soil and
were analysed for their Zn concentrations after harvest. Results of this study showed that, common lambsquarter was
more tolerant to low and medium concentrations (≤900 mg/kg), but sorghum tolerated high concentration of Zn. Also
sorghum was more capable in removal of Zn from soil in comparison to common lambsquarter, so that soils
contaminated with low Zn levels (≤900 mg/kg) can be remediated by sorghum. In addition, there was a significant
correlation between 1 M NH4NO3-extractable soil Zn and the plants response (relative yield and shoot Zn concentration)
to soil Zn contamination.
H. Khodaverdiloo, N. Hosseini Arablu,
Volume 18, Issue 67 (Spring 2014)
Abstract
Cation exchange capacity (CEC) is one of the important indices in soil fertility. Direct measurement of CEC is time consuming and expensive, especially in aridisols containing high amounts of carbonates and gypsum. Alternatively, CEC could be indirectly predicted through pedotransfer functions (PTF). The objective of this study was to predict CEC using class and continuous PTFs.A data set (n = 977) was classified according to the soil textural class and was used to derive the PTFs. Another independent set (n = 173) was used to test the reliability of the PTFs. The root mean of square error (RMSE), mean error (ME) and index of agreement (d) were applied to evaluate the PTFs. Within every textural class, we furthermore evaluated the relative improvement (RI) of the continuous PTFs over the corresponding class PTF. The continuous PTFs were more accurate than class PTFs for finer textural classes while the former showed higher reliability in coarser textural classes. With an increase in relative particle size, prediction bias of class PTFs decreased RMSE was 8.55 and 3.88 in clay and sandy loam textural classes, respectively. Consequently, according to the results obtained in this study, for the prediction of soil CEC, continuous PTFs are suggested to be used for silty loam and finer textural classes while for loam and coarser classes application of class PTFs is preferred.
M. H. Rasouli0-Sadaghiani, H. Khodaverdiloo, M. Barin, S. Kazemalilou,
Volume 22, Issue 1 (Spring 2018)
Abstract
The use of plants and soil microorganisms is a promising technique for the phytoremediation of heavy metal-contaminated soils. This study was carried out in order to evaluate the soil microbial potential with four Cd concentration levels (0, 10, 30 and 100 mg kg-1); the study also addressed the inoculation of arbuscular mycorrhizal fungi (AMF) species (a mixture of Glomus species including G. intraradices, G. mosseae and G. fasciculatum) as well as plant growth promoting rhizobacteria (PGPR) (a mixture of Pseudomonas species including P. putida, P. fluorescens, and P. aeruginosa) with the Centaurea cyanus plant. The soil sample was spiked uniformly with Cd nitrate salt to create different Cd concentrations. The contaminated soils were then sterilized and subsequently inoculated with AMF and PGPR. The results indicated that with increasing the soil Cd concentration, colonization percent, abundance of rhizobateria, shoot biomass, and shoot relative biomass were significantly decreased, while the proline content and the shoot Cd concentration were significantly increased (P≤0.05). The mean of Cd extracted in AMF and PGPR treatments was 1.8 and 2.8 and the translocation factor was 1.2 and 1.5 times higher, as compared to the corresponding control treatments, respectively. It could be concluded that microbial inoculation, in addition to improving plant growth, plays an important role in the Cd phytoremediation efficiency by plant.
M. H. Rasouli-Sadaghiani, H. Karimi, S. Ashrafi Saeidlou, H. Khodaverdiloo,
Volume 22, Issue 4 (Winter 2019)
Abstract
Because of the undesirable effects of lead on soil properties and human health, evaluation of its remediation methods seems to be essential. In order to evaluate the effect of humic acid (HA) on the decontamination of lead (Pb) spiked-soils in the presence of wormwood plant (Artemicia absantium), an experiment was carried out in a completely randomized block design with three replications. Experiment factors including different concentrations of Pb (Pb(NO3)2 in the solid form) (0, 250, 500 and 1000 mg kg-1) and levels of HA (0, 100 and 200 mg kg-1) were considered. At the end of the growing period of plants, some soil and plant properties were measured. According to the results, BR, MBC, root and shoot dry weights, RWC and Fe and Zn concentrations in the shoot were decreased by increasing the soil Pb concentration. So, the mean values of BR and MBC in Pb1000 treatment was 60 and 51.1 percent lower than those of Pb0, respectively. Pb accumulation in the root and shoot was enhanced as a result of the increase in the soil Pb concentration. The maximum Pb concentration of shoot (37.10 mg kg-1) and root (38.1 mg kg-1) was seen in the Pb1000 treatment. Also, the results suggested that humic acid had a positive effect on the shoot of Fe, Zn and Pb concentrations. So, the concentration of these elements in HA200 treatment showed an increase 1.25, 1.64 and 1.66 times more than that of HA0, respectively. Leaf proline amount was increased significantly by elevating the soil Pb concentration; however, application of 200 mg kg-1 humic acid decreased leaf proline by 54.5 percent, as compared to the control (HA0). Therefore, humic acid effect on increasing the plant Pb uptake, improving soil biological properties, and increasing availability and dissolution of Pb showed its ability in promoting the phytoremediation efficiency. According to the obtained results of this study, woodwarm plant (Artemicia absantium) is a non-accumulator that could not be used for phytoremediation purposes.
