نشریه علوم و تکنولوژی محیط زیست
سال بیست و چهارم شماره 10 (پیاپی 125، دی 1401)

In recent years, excessive use of agricultural inputs has increased energy consumption and greenhouse emissions. This study aims to investigate the energy flow and greenhouse gases emissions in the production systems of some crops in South Khorasan province.

In the current research, a questionnaire, as well as face-to-face interviews with the farmers in this region (2018), were used to collect the required information, including agricultural operations, the type and amount of consumed inputs and product performance. In the present research, input energy, output energy, net energy, specific energy, optimal energy consumption, energy efficiency indices, different forms of energy, and Global warming potential were calculated and evaluated.

The results showed that the process of alfalfa production had the highest energy consumption. On the other hand, Sugar beet (571,200 MJ.ha-1), fodder sorghum (391,920 MJ.ha-1) and alfalfa (120,870 MJ.ha-1) have the highest energy output, respectively. A comparison of the studied products showed that rapeseed (27.6 MJ.kg-1) and cotton (15.3 MJ.kg-1) have the maximum specific energy index. The ecosystems of alfalfa (41566 kg CO2eq.ha-1), sugar beet (29179 kg CO2eq.ha-1), fodder sorghum (27396 kg CO2eq.ha-1) had the maximum of global warming potential (GWP), respectively. Comparing the share of different inputs from the total global warming potential of the products showed that electricity, nitrogen fertilizer, and diesel play the greatest role in greenhouse gas emissions in all the studied products.

Since electricity and nitrogen fertilizer had the greatest role in the greenhouse gases emission from crops in South Khorasan province, management and optimization of irrigation performance and appropriate agricultural activities such as green manure crops or legumes cultivation to increase soil fertility, can be a solution to reduce greenhouse gas emissions in the South Khorasan region.

In the present time, land use changes are being conducted without clear and logical programming or regarding the environmental effects of the changes. Because land use changes occur in a large scale, remote sensing technique is a useful and valuable tool for monitoring the changes. The aim of this research is investigation of the effects of land cover changes on rangelands of Ghoorichay chatchment located in the north of Ardabil province using remote sensing technique.

In this investigation, TM images for year 1987, ETM images for year 2001 and OLI-TIRS images for year 2015 were collected and analyzed. After image pre-processing enhancements and corrections, the images were classified using maximum likelihood supervised classification method. Then, considering study area features, the images were classified into four land cover classes: dry land, range land, bare land and village. Moreover, NDVI index and slope layer were used to increase classification accuracy. At last, land cover changes and their effects on the range lands were detected. Overall accuracies and kappa coefficient were evaluated.

According to the results, during the studied period, 5885 hectare (49.7%) of study area had changed. The most land cover changes were related to range land with intensive decrease of 2540 hectares (21.4%) which was changed into bare land and dry land.

Additional information such as slope layer and NDVI index in assistant with supervised classification of satellite images can increase the accuracy of image classification to provide land cover maps.

Hepatotoxins are dangerous biological toxins produced by cyanobacteria. Because of the high consumption of cost and time in the extraction and detection procedure of these toxins, the main aim of the present study is to investigate the performance of a new extraction technique, termed dispersive liquid-liquid microextraction (DLLME) in the extraction of one hepatotoxin with the name Microcystin LR from water samples, using chlorinated organic extraction solvents.

In the first stage, the efficiency of the common method (solid phase extraction) was investigated. Then the mixture of disperser solvents (acetone, ethanol, methanol, and acetonitrile) and extraction solvents (chloroform, dichloromethane, carbon tetrachloride and tetrachloroethylene) were used to investigate the efficiency of DLLME.

The results showed that the efficiency of SPE using a C18 cartridge was 102 %. For high efficiency of DLLME, a cloudy solution should be formed (fine particles of extraction solvent which are dispersed entirely into the aqueous phase). In the present study, only in a mixture of acetone and tetrachloroethylene (with different ratios), a stable cloudy solution was found. The best-observed efficiency was 3 % for DLLME.   

The observations in this study suggest that although based on the obtained efficiency, the chlorinated organic solvents, could not be appropriate extraction solvents in MC-LR extraction, but the DLLME method using other solvents like Ionic liquid extraction solvents is a suitable technique for hepatotoxin extraction because of low consumption of cost, time and solvents in the extraction procedure.

One of the most important problems of modern society is water pollution.  Among these pollutants are organic dyes pollutant in industrial factories effluent, which the removal them is very important. The purpose of this study is to provide a solution to eliminate the methyl orange organic dye in industrial factories wastewater by Spark plasma.

In this study, the decolorization and degradation of methyl orange solution were investigated by electrical discharge plasma method at the water-gas interface. The electrical discharge device used in the present work is spark type plasma with needle-plate electrode structure, with effective voltage 1-12 KV and constant frequency 13 KHz.

The results show that decolorization and degradation of methyl orange dye solution begins at the air-gas-air interface, which can be due to ultraviolet radiation and production of OH radical and highly reactive species H2O2 at the air-gas interface. The effects of the discharge device parameters such as the applied voltage, electrode gap, treatment time and also chemical effects of the solution such as the concentration of the dye have a significant role on decolorization. The results showed that with increasing voltage and increasing treatment time, the amount of decolorization increases, and also by keep the electrical power of the device constant, the amount of decolorization decreases with increasing concentration. Selecting a distance of 2 cm between the electrodes, the highest amounts of decolorization in solution have been observed.   

In this reactor, the initial pH has no significant effect on decolorization efficiency. Also, the highest decolorization rate of 99.8% occurred at a concentration of 30 ppm, effective voltage 10 KV, electrode gap of 2 cm, initial pH = 3 and in 30 minutes treatment time.

Freshwater scarcity is leading the world to research into the reuse and recycling of industrial wastewater.

In this research, in order to improve the quality of the effluent of the treatment plant and the possibility of using it as a source of fire water, the effluent of the wastewater treatment plant of Gharb town was used as an analysis unit. On-site sampling and qualitative tests were performed on samples prepared in 20 liter containers in Tehran University Laboratory. In other words, the method of conducting the present study was laboratory. Data collection tools in this study consisted of pH meter, TDS meter, spectrophotometer DR5000, turbidimeter, and thermal reactor.

This research investigates on Electro-Coagulation and Hydraulic Retention time and the way that it effects on treated wastewater Quality, for so, 9 samples with 20 liters’ plastic pot has been taken and examined in different contact time including 1, 2, 5, 10, 24, 48, 72 hours. The results show that all goals parameters (pH, Total Dissolved Solid (TDS), Phosphate, chloride, Sulfate, total Hardness, Silica, suspended solid (SS), Iron (Fe) and Manganese (Mg) are in standard Range but there is in one sample the Chemical Oxygen Demand (COD) was not in standard Range. Also the experiment shows that all parameters concentration was decreased by time except Hardness and Sulfate which were increase. Also Biologic Parameters examined as well and they were on standard Range.

The results show that the treated wastewater Quality was in Standard Range till 72th hours and after this time due to rapid increasing of Sulfate and increasing of its smell it not suitable for use as water source in firefighting. Further more 9 other samples had been examined after using Electro-coagulation as an advanced treatment and disinfection aid fallowing by Sodium hypochlorite disinfection, the result shows that COD is decreased and all parameters got better for reuse, especially Biological parameters.

Hills, as one of the main components of the ecological structure in a hilly town, are influenced by human actions and affect them. The landscape Ecology Approach examines diverse ecosystems at different scales and balances human actions and natural processes. In this study, changes in the ecological structure of four significant hills in Sanandaj (Tosonozar, Nishtman, Mellat, and Didgah) were investigated using Google Earth images and two ecological metrics over 16 years (2020-2004).

The ecological structure of these hills was investigated by object-oriented method in six classification categories and their changes. Also, by using FRAGSTATS 4.2 software, the status of two ecological indicators, FRAC and CONTIGH, were calculated and checked in the hills until 6/20/2019.

Man-made elements have increased (19%) in all hills, especially in Nishtman. Also, rangeland cover has decreased (32%), especially in Tusunozar and Nazgah hills. The complexity of landscape spots in all hills except Toos-Nozar has increased. Also, the continuity Toos-Nozar has decreased except Toos-Nozar hill.

The elimination of pastures and plant species, the increase in recent fires and droughts, and the increase in human interventions such as construction and motorways, the cohesion and ecological flows of these hills have posed a severe threat. Simplification while homogeneity of landscape components in Toos-Nozar hill indicates the distance of landscape components from their natural state. The decrease in continuity in the three hills, including Mellat, Didgah, and Nishtman, indicates an increase in fragmentation and discontinuity in these hills' natural landscapes.