Elham Noshadi; Mehdi Homaee; Mohammad Mahmoudian Shoushtari
Volume 15, Issue 2 , July 2017, , Pages 111-128
Abstract
Introduction:
Contamination from agricultural inputs, particularly herbicides, is one of the most important environmental challenges and the use of modern technologies such as herbigation has intensified this problem. Thus, employing optimal management strategies based on knowledge of herbicide behaviour ...
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Introduction:
Contamination from agricultural inputs, particularly herbicides, is one of the most important environmental challenges and the use of modern technologies such as herbigation has intensified this problem. Thus, employing optimal management strategies based on knowledge of herbicide behaviour and processes in soil is necessary. The objective of this study was to assess quantitatively the herbicide adsorption-desorption behaviour in soil in the laboratory and under real field conditions.
Materials and methods:
Consequently, metribuzin was applied to the experimental plots using the herbigation (HRB) and conventional spraying (CS) methods, and to laboratory samples. After inspecting the adsorption and desorption behaviour of herbicide by batch and centrifugal methods, different models of equilibrium adsorption were fitted to the data.
Results and discussion:
Results indicated that, due to the low amount of organic matter and clay in the soil, herbicide adsorption was generally weak in all three types of treatment and that the overall process followed the Freundlich model. The results further showed that in all three treatments because of the adsorption mechanism’s weak hydrogen bond, a large portion of the adsorbed molecules desorbed after four washing cycles. However, in the laboratory and herbigation treatments, the amount desorbed was relatively less and, due to the diffusion of molecules into inter-aggregate pores, a small hysteresis can be seen.
Conclusion:
In conclusion the results show, the adsorption amount in laboratory and herbigation treatments is greater than conventional spraying treatments due to a higher moisture level in the soil and increased hydrophilic sites on organic matters and diffusion within the inter-aggregate pores. Therefore, the methods of pesticide application affect the adsorption and desorption behaviour of it. So pesticide application by herbigation is suggested in order to reduce losses and increase efficiency in the field.
Mansour Chatrenour; Mehdi Homaee; Safoora Asadi Kapourchal; Mohammed Mahmoodian Shoshtari
Volume 14, Issue 1 , April 2016, , Pages 29-38
Abstract
Quantitative description of soil hydraulic properties is crucial for preventing organic contaminations entering into the soil and groundwater. In order to assess hydraulic behavior of Perchloroethylene, as a toxic chlorinated contaminant in soil, retention curves of Perchloroethylene and water were determined. ...
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Quantitative description of soil hydraulic properties is crucial for preventing organic contaminations entering into the soil and groundwater. In order to assess hydraulic behavior of Perchloroethylene, as a toxic chlorinated contaminant in soil, retention curves of Perchloroethylene and water were determined. The Saturated hydraulic conductivity of both examined fluids was determined by constant head method. The Perchloroethylene and water hydraulic conductivities were obtained to be 492.84 and 450.27 cm day-1, respectively. The porous medium retention parameters is obtain based on van Genuchten, Brooks-Corey and Kosugi retention models. Further, the unsaturated hydraulic conductivity for both fluids were obtained based on Mualem-Brooks-Corey, Mualem-van Genuchten and Mualem-Kosugi models. The accuracy performance of models were assessed by some statistics including ME, RMSE, EF, CD and CRM. Results indicated that the van Genuchten model providing better estimations than other models when the studied fluid was Perchloroethylene. The results further indicated that the magnitudes of the pore-size distribution parameters and the bubbling pressure parameters are reduced in water-air system compares to Perchloroethylene -air system. This can be attributed to high viscosity of water and its considerable resistance against flow. This implies that more suction is needed to drain out water from porous medium than Perchloroethylene. Consequently, porous medium provides less retention for Perchloroethylene at a given quantity of fluid than water. Owing to less amount of Perchloroethylene viscosity, the saturated and unsaturated porous medium hydraulic conductivity of Perchloroethylene was more than that of water. Since Perchloroethylene has lower retention and larger hydraulic conductivity than water, its infiltration into porous medium would lead to faster movement towards groundwater.
Donya Mottaghi; Mehdi Homaee; Rasoul Rahnemaie
Volume 13, Issue 2 , July 2015, , Pages 75-88
Abstract
Soil contamination is one of the most recent and important environmental challenges worldwide. The so-called phytoremediation is one of the reclamation technologies used to decontaminate polluted soils. Application of some chelate agents can increase the efficiency of phytoremediation. However, this ...
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Soil contamination is one of the most recent and important environmental challenges worldwide. The so-called phytoremediation is one of the reclamation technologies used to decontaminate polluted soils. Application of some chelate agents can increase the efficiency of phytoremediation. However, this technology has not been evaluated for decontamination of heavy metals under multicropping system. The objective of this study was to evaluate the phytoremediation capability of cress and radish, as a mixed-culture by using some natural and synthetic chelates in Cd-contaminated soils. Consequently, a factorial experiment in a completely randomized design with 20 treatments and three replications was conducted. The experimental factors were consisted of five levels of cadmium (0, 3, 10, 25, 50 mg Cd kg-1 soil, added as Cd(NO3)2, EDTA and NTA chelates, and chelate concentrations of 1 and 2.5 mmol kg-1 soil. Results indicated that the Cd phytoextraction potential in multicropping culture is higher than the single-cropping system. Phytoextraction of cadmium from contaminated soils for both cress and radish plants, in EDTA2.5 and Cd50 treatments was 7.7 and 5.7 kg Cd ha-1 in multicropping system and was 4 and 5.4 kg Cd ha-1 in the single-cropping system. Furthermore, radish could phytoextract more cadmium than cress from the contaminated soils. The results further indicated that EDTA could enhance more Cd phytoextraction than NTA and can better assist to transfer cadmium from roots to shoots.
Mahnaz Eskandari; Mehdi Homaeei; Shahla Mahmoodi
Volume 11, Issue 3 , October 2013
Abstract
Landfill siting is a complicated landuse planning task. For optimized site selection, several environmental, technical, economical and socio-cultural criteria must be considered. This study presents a method for landfill site selection based on using the multi criteria decision analysis (MCDA) and geographic ...
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Landfill siting is a complicated landuse planning task. For optimized site selection, several environmental, technical, economical and socio-cultural criteria must be considered. This study presents a method for landfill site selection based on using the multi criteria decision analysis (MCDA) and geographic information system (GIS) combined with related experts opinions. The proposed method was then tested for siting of Municipal solid waste (MSW) landfill in Marvdasht. In the intelligence stage of the decision making, based on sampling and questionnaire results of 40 experts in MSW domain, some evaluation criteria were determined. Suitable maps were then obtained and digitized to make a GIS database of the study area. In decision making design step, two stages were employed. In the first stage, 13 constraints based on Iran’s environmental protection organization were determined. The Boolean map of spatial constraint was obtained with AND operation. In the second stage, the suitable site that was obtained in the first-stage analysis was evaluated in details based on 16 factors. The criteria were standardized and then the relative importance weight of them was estimated with rank ordering method based on different expert’s opinions. The obtained results of firs step indicated that only 11.12 percent of the whole region is suitable for landfill siting. Therefore, shortage of land is an important limiting factor in the study area. The obtained results of second step indicated that almost 4.4 percent of the whole region can be considered as best suitable place for landfill site. Keywords: GIS, Landfill Siting, Multi Criteria Decision Analysis, Municipal Solid Waste
