Showing 22 results for Risk
Mansour Zibaei, Gholam Reza Soltani, Ahmad Ali Keykha,
Volume 2, Issue 4 (1-1999)
Abstract
The production and acreage of corn in Iran and in Fars Province, in particular, are expanding at an increasing rate. The impacts of this event was studied by a risk programming model (MOTAD). The results indicated that the optimal cropping patterns with corn had less variance than the optimal patterns without corn in all income levels. The results also showed that with the introduction of corn into cropping pattern, the use of land and water were increased, but the rate of increase in the use of land was more than the rate of increase in the use of water. By determining risk - aversion coefficient for the sample farmers, their sensitivity to corn price changes were studied. The results indicated that the relationship between corn and wheat is complementary but it is competing with barley, sugarbeet, cotton, cucurbits and legumes.
A. Abdeshahi, G. Soltani,
Volume 4, Issue 1 (4-2000)
Abstract
Successful implementation of socio-economic projects depends on the degree of planners’ awareness of farmers’ risk coefficient. Because agriculture is a risky activity, knowledge about the farmers’ attitudes toward risk in each area is essential. This research investigated the farmers’ risk behavior in Homayjan district in Sepidan township. Cross-section and time series data were collected from a random sample of farmers and from Agricultural Department of Fars Province, respectively. In this study, the Safety First Rule (SFR), Generalized Stochastic Production Function (GSPF) and Target Motad models were used.
The results indicated that in this area, farmers are risk averse in crop production, but they have a low risk coefficient in the use of modern inputs. Signs of GSPF revealed that the use of modern resource input reduces risk. Target Motad risk programming model confirmed that farmers are risk averse because with increasing risk, crops like wheat that have relatively stable prices and yield enter the model, while crops like onion that have high instability in price and yield are omitted from the model.
J. Torkamani,
Volume 5, Issue 2 (7-2001)
Abstract
The main objective of the present study is to analyze the effects of agricultural crop insurance on farmers’ technical efficiency and risk attitude. Required data came from questionnaires that were completed by the Institute for Planning and Agricultural Economics of the Ministry of Agriculture. Farmers’ technical efficiency and attitude toward risk were estimated using stochastic frontier production function and equally likely certainty equivalent method for both insured and non-insured groups. Results revealed that effects of agricultural insurance on farmers’ technical efficiency were significantly positive in the three study regions.
Results of estimating risk aversion coefficients of study farmers showed a positive effect of insurance on risk aversion coefficients. However, this effect was significant only in two of the climatic regions under study.
A. R. Nikooie, J. Torkamani,
Volume 6, Issue 2 (7-2002)
Abstract
Agricultural insurance is one of the appropriate ways to overcome the risk in agricultural production and to increase farmers’ income security. In this study, the influence of wheat insurance, as personal-free insurance, and sugar beet insurance, as group-forcible insurance, on farmers’ risk attitudes in Fars Province were investigated as a case study. Data were collected using stratified multi-stage cluster sampling method and interviews in the years 1375-1376. The sample included wheat and sugar beet farmers in three different climates including Mediterranean, warm sub-desert and cold mountainous in Fars Province.
Results of estimating risk aversion coefficients of farmers, using Safety First Rule (SFR), showed that sugar beet forcible insurance along with giving inputs, mechanization services, lookout of farms by sugar plants led to continuous insurance purchase by farmers in consecutive years. Therefore, sugar beet farmers tended to welcome insurance and the effect of insurance on their risk aversion coefficients was positive. However, discontinuity of insurance purchase by wheat farmers in consecutive years and farmers’ lack of confidence in insurace system caused the influence of insurance on wheat farmers’ risk aversion coefficient to be insignificant. Thus, sugar beet insurance type is closer than wheat insurance type to one of the main aims of agricultural insurance system, which is increasing farmers’ tendency to take risks.
J. Torkamani, Sh. Shajari,
Volume 10, Issue 4 (1-2007)
Abstract
This paper investigates the effects of wheat production risk and other socio-economic factors on the probability of adopting new seed technologies. Also, the effects of production inputs and production conditions are examined on wheat production yield and risk. Moreover, the relative risk of new seed varieties will be examined under different scenarios. To carry out the study, farm-level data was collected from a sample of 187 wheat farms located in Fars province, and selected by multi stage random sampling method during the years 2001 and 2002. A generalized stochastic production function by a three-stage estimation procedure was used to determine the influential factors on the production yield and risk. The results showed that yield uncertainty could not be sufficiently explained by the level of input use in the cultivation of both wheat varieties. The comparison of two wheat varieties cultivation indicated that in the absence of suitable production conditions, on the average, the cultivation of new wheat varieties ensures greater yield than traditional wheat varieties, but involves greater risk, as measured by yield variance. Accordingly, the farmers’ risk aversion attitude could be a major factor inhibiting speedy diffusion of new wheat varieties, which besides having greater average yield than traditional wheat varieties, it has less production risk. The results indicated that the risk associated with seed has negative effect on the adoption of new seed technologies.
J. Torkamani, M. Sabohi,
Volume 11, Issue 1 (4-2007)
Abstract
The endogenous selection and determination of return reference level is important in specifying risk efficient set. Thus, using multi-objective programming, Target–MOTAD in the framework of Mean-PAD and maximin parametric analysis models was established to obtained reference level of return endogenously. To determine non–inferior set for the farmers understudy, at first, the pay-off matrix was obtained through maximizing objectives under consideration. Then, upper and lower bounds of non-inferior set were determined using non- inferior set estimation (NISE) technique. The results obtained from maximin model indicated that Min and Max of maximin model were 270252 and 217753 thousands Rials, respectively. Furthermore, a subset of non-inferior set was obtained using different return reference levels. Comparing the results of model and the current farmers' plan showed that the current acreage of crops, except for sugar beet was approximately placed in the range determined by the model. In addition, the results also indicated that farmers' plan could be a non- inferior set. Considering the importance and also scarcity of water in the study area, average water return in the farmers' plan was compared to non-inferior set which included all the upper and lower non-inferior set. The results showed that farmers obtained 18150 Rials per hours of used water. However, average water return changed the range of 19100 to 30200 Rials for non-inferior set, indicating that farmers are able to use water more efficiently. The results also showed that changing farmers' cropping pattern is a complicated task and that it is necessary to have a systematic view in ordere to achieve desirable change.
H Faghih, M Kholghi, S Kochekzadeh,
Volume 12, Issue 46 (1-2009)
Abstract
Overtopping is one of the main factors responsible for dam failure. To avoid overtopping, dam is equipped with one or some spillways to release the water impounded in the reservoir. The number and size of these spillways are determined on the basis of design flood. Determination of design flood of dam spillway can be formulated as a multiobjective risk problem. This problem can be solved by Quantitative Risk Analysis Methods. Here, four economical design methods which are based on risk analysis including, United States National Research Council (NRC), US Civil Engineering, Unit Curve and Partitioned Multiobjective Risk (PMR) were studied. In order to compare these methods, Risk Analysis was performed for re-determining design flood of Pishin Dam Spillway. This Dam has been constructed on the Sarbaz River. Owing to the fact that the integrals of the expected damage relations in the two methods, i.e., Civil Engineering, and Partitioned Multiobjective Risk are analytically unsolvable, Romberg numerical integration technique and Excel software were utilized for the related calculations and drawing graphs. Also, in order to select suitable distribution, the flood analysis was done using Smada software. The findings of the study indicated that design flood determined by the three methods, i.e., Civil Engineering, National Research Council and Unit Curve was almost the same, and that the amount of flood was less than the 10,000-year-old flood while design flood determined by Partitioned Multiobjective Risk Method, was larger than the 10,000- year-old flood.
M Kopahi, H Sadat Barikani, M Kavoosi Kelashomi, M Sasoli,
Volume 13, Issue 48 (7-2009)
Abstract
Risk and uncertainty have an important role in determining farmers' goals and their decision making. Risk affects optimal use of inputs and production efficiency. Using production inputs especially new inputs is one of the effective factors in production risk hence, it is necessary to obtain information about inputs use risk in order to find solution to risk management. For investigating effect of inputs use on production risk of rice crop in Gilan province, a quadratic form of production function was applied. Mean production function indicates constant return to scale. Also, risk production function shows increasing acreage and use of fertilizer cause increase in production risk of rice crop. Therefore, consolidating program of rice acreages and policy of paying subsidies to fertilizer input should be managed by considering producers' conditions.
S. Ghaseminejad, S. Soltani, A. Soffianian,
Volume 18, Issue 68 (9-2014)
Abstract
Drought is a one of the most important natural disasters that have high socio-economic and environmental impacts.
However, drought is more than a physical phenomenon or natural event. Its impact results from the relation between a natural event and demands on the water supply, and it is often exacerbated by human activities. The traditional approach to drought management has been reactive, relying on crisis management. Due to the drawbacks of crisis management, employing proper risk management techniques has been suggested. In order to move from crisis management to risk management, in this study, risk of drought in Isfahan province was evaluated. Drought hazard index and vulnerability index are components of the drought risk management. Standardized Precipitation Index (SPI) was used as the index of drought hazard. For the calculation of SPI, the monthly rainfall data in 47 meteorological stations during the period of 1975-2007 were collected. The time series of rainfall data were prepared and for calculation of the standardized precipitation index in a 12 month timescale they were imported to SPI program. Percentage of drought occurrence in each severity was calculated and then the drought index map was obtained. Vulnerability index was calculated through socio-economic indicators (population density and percentage of people involved in agriculture), and physical indicators (available water capacity of soil and land use). Weighted Linear Combination (WLC) technique was applied for combination of vulnerability indicators. To assign weights to the criteria, an Analytical Hierarchy Process (AHP) was used. After providing the maps, fuzzy membership functions for every criterion were used for their standardization. For the weighting of the criteria, a questionnaire was prepared and criteria comparison was done using the participatory approach by a group of experts. Finally, the drought risk index was calculated by multiplying the drought hazard index and vulnerability index. The results showed that hazard of very severe drought is mainly concentrated in the central part of province. The North and North East of Isfahan province could experience condition of severe drought. South West of Isfahan province is under moderate drought condition compared to the other parts of the province. Map of drought vulnerability index showed that the most vulnerability is in the West, South and North-East of province. Map of drought risk index showed that the Northern Province demonstrated high risk. To reduce the drought risk in Isfahan province, improving monitoring, early warning, increasing environmental awareness, and promoting water resource management practices should be considered.
M. Ebrahimi, M. Jafari, E. Rouhimoghaddam,
Volume 19, Issue 72 (8-2015)
Abstract
The present study was conducted to increase phytoextraction efficiency of Festuca ovina L. in lead contaminated soil in the EDTA-assisted (0, 1.5, 3, 1.5+1.5, 3+3, 6 mmol kg−1), assess the best time of plant harvesting to increase Pb uptake and method of EDTA application to reduce Pb leaching risk. The results revealed that the greatest Pb uptake was observed in 3EDTA treatment. Therefore, 3mmolkg-1 was used in the second step for assessing harvest time for 15, 30 and 45 days. Results showed that the concentration of Pb in plant tissues was increased with the passage of time and the best harvest time to achieve maximum removal of Pb was 60 days of the first harvest. In the third step to reduce leaching of Pb-chelate, 3mmolkg-1 EDTA in five ways of single, double, triple, quadruplet, quintuplet were added to the soil. The results indicated that under quintuplet application, Pb content reached its minimum concentration in the soil and in the plant organs, the Pb concentration was maximum and metal concentration in the plant organs did not vary significantly when triple, quadruplet and quintuplet dosages were added (p<5%). Overall, optimum phytoextraction of F. ovina L. and Pb leaching reduction were achieved when 3mmol kg−1 EDTA was added in quintuplet dosage and the plant was harvested at the end of growth stage.
H. Kheirabadi, M. Afyuni, S. Ayoubi, A. Soffianian,
Volume 19, Issue 74 (1-2016)
Abstract
Heavy metals are known to have deleterious effects on human health. The main route of human exposure to heavy metals is the daily intake of food. This study was designed to investigate the heavy metal concentrations (Cu, Zn, Mn, Fe, Cr, Ni and Cd) in soil and major food crops (wheat, potato and corn) and estimate the health risks of metals to humans via soil and the crops consumed in Hamedan Province, using the total non-cancer hazard quotient. Daily metal intakes were estimated for three receptor groups and then compared with health guideline values. The non-cancer risk estimations showed that chromium, manganese, cadmium, zinc, Iron, Nickel and copper have oral Hazard Quotient values less than a value of one. The Hazard Index values were greater than 1 for all age groups, suggesting that adults and children in the study area may experience a potential non-cancer risk due to diet of heavy metal via wheat, corn and potato consumption and soil ingestion. Consumption of plant foods particularly wheat was found to be the major route of human exposure to heavy metal. The soil ingestion route is also important.
M. Touzandejani, A. Soffianin, N. Mirghafari,
Volume 22, Issue 2 (9-2018)
Abstract
Among the heavy metals, arsenic is known as a carcinogen material and its high concentrations in the ecosystem can be a major concern for public health and environment. The aim of this study was to evaluate the risk map of arsenic contamination and the possibility of its entering into the food chain using the fuzzy method in the central part of the Hamedan-Bahar plain. For this purpose, arsenic concentration in 94 points of groundwater and 49 points of surface soil was analyzed and evaluated in the study area. Soil physico-chemical parameters (clay, organic matter and pH), soil and groundwater contamination probability map, and land use map were selected as the input of this method. In the fuzzy method, two operators (and & or) were used. In order to standardize the parameters, the fuzzy linear function was used. Comparing the classified risk assessment using these operators showed that the results of the operator had the maximum trust. So in areas where concentrations of arsenic in soil and groundwater were high, the physico-chemical parameters such as pH, organic matter and clay content of the soil were low and agriculture products had a high ability to absorb heavy metals and ensure its better to use for the operator.
H. Babaei, N. Ghanavati, A. Nazarpour,
Volume 22, Issue 3 (11-2018)
Abstract
Dust particles are suspended particles created from various natural and anthropogenic sources. Dust particles contain toxic metals, such as mercury (Hg), which can have harmful effects on the human health. In this study, to investigate the contamination level of Hg in the street dust in Ahvaz, 95 dust samples were collected from the pavements in the main streets. The concentration of Hg in the collected samples was determined by the atomic absorption method (ASS). The contamination level was estimated based on indicators such as contamination factor (Cf), enrichment factor (EF), geo-accumulation index (Igeo) and ecological risk index (Er). The concentration value of mercury ranged from 0.02 to 8.75 mg/kg with an average of 2.53 mg/kg. The results of pollution indicators showed that the level of Hg contamination in the street dust of Ahvaz was a high level of contamination. In addition, the results of ecological risk assessment indicated that the ecological risk of Hg in the study area was very high. Spatial distribution pattern of Hg concentration showed that in areas with high population density, high traffic volume and industrial activities, there was a high pollution level of Hg.
K. Nosrati, M. Heydari, M. Hoseinzadeh, S. Emadoddin,
Volume 22, Issue 3 (11-2018)
Abstract
Ziarat drainage basin, in the southern part of Gorgan city, is exposed to mass movement, especially landslide occurrence, due to geologic, geomorphologic, and anthropogenic reasons. The objectives of this study were to predict landslide susceptibility and to analyze the effective factors using rare events logistic regression. In view of this, the map layers of the variables including geology, land use, slope, slope aspect, distance of road, distance of fault and distance of river were prepared using topographic and geologic maps and aerial photo interpretation. In addition, the map layers of the soil variables including the percent of clay, silt, sand, and saturation water as well as plasticity limit index were determined based on the laboratory analysis of 32 soil samples collected from landslide sites and 32 soil samples obtained from non-occurrence landslide sites. The controlling factors of landslide were determined using rare events logistic regression analysis; then based on their coefficients, the landslide risk zoning map was prepared and validated. The landslide risk zoning map was classified in five different hazard classes ranging from very low risk to very high risk; the very high risk class with 16.8 km2 was assigned as the having the highest percent of the catchment area. The results of the model validation showed that the rare events logistic regression model with the receiver operating characteristic (ROC) of 0.69 could be a suitable prediction model for the study area. The results of this study could be, therefore, useful for corrective actions and watershed management landslide high-risk zones.
B. Atashpaz, S. Rezapour,
Volume 23, Issue 2 (9-2019)
Abstract
The present study was conducted to evaluate the ecological risk indices of Zn, Cu, Cd, Pb and Ni in the soils from Urmia region (Ghahramanloo village), as irrigated with treated wastewater. Accordingly, six different soil sites (five soil sites under wastewater irrigation and one soil site under well water irrigation as the control) were selected and sampled (AP horizon, 0-30 cm depth). Soil samples were air dried, passed through a 2-mm sieve, and analysed to determine the chemical properties and the studied heavy metals. The results showed that irrigation with the treated wastewater significantly increased the total elements in the order of Cd (228%)> Zn (118.5%)> Ni (81.5%)> Pb (54.2%)> Cu (23.5%). Nevertheless, with the exception of cadmium, other elements were within the admissible range based on the national and international standards. Ecological risk index (min = 125, max = 152, mean = 140) showed a considerable risk in all studied soils and Cd could be regarded as the major metal affecting the index yield.
A. Jamal, A. Parvan, D. Valizadeh,
Volume 23, Issue 4 (12-2019)
Abstract
Today, the preparation of flood zoning maps is one of the basic and important issues in the study of development projects in the world; it is considered before any investment by the related organizations. In this paper, flood zoning was performed using the two-dimensional model HEC-RAS and GIS in order to assess the risk of the construction of a railway station near the bank of the Iranshahr River, in a range of 2500 meters. Two-dimensional hydraulic application could create a more accurate flow pattern in comparison to the one-dimensional model used in the previous studies, especially in the flood plain areas. In this paper, due to the important role of the topography of the area in ensuring the accuracy of the calculation, a Digital Elevation Model (DEM) was used with very high precision (about 2 meters), as obtained from aerial photos. The results of this study indicated the onrush of flood, depth and flow velocity in different return periods. Based on the comparison of water surface profiles in the floodplains with the return period of 100 and 25 years, the maximum difference between the water levels was 0.5 m, which seemed to be reasonable by considering the low slope of the studied area. The results of this paper, therefore, showed that the location of the railway station was in medium risk and the outskirt of floodplain.
N. Alian, M. M. Ahmadi, B. Bakhtiari,
Volume 23, Issue 4 (12-2019)
Abstract
One of the most important problems in flood manegment is the damages induced by this phenomenon. Expected annual damage (EAD) is an important index for basin vulnerability against flood. Prediction of flood damages requires the analysis of spatial and temporal risk and must be calculated by the combination of hydrologic, hydraulic and economic models. In this research, the uncertainty was considered in the flood risk analysis. The probability of flood occurrence was calculated by the parabolistic model. By using the river analysis systems software (HEC-RAS) and the geographic information system (GIS) and utilizing the Google-Earth software, the floodplains of Zayande Roud river in Esfahan province were investigated with the return period of 25, 50, 100, 200 and 500 years. The Monte Carlo method was also sed to perform the uncertainty analysis in the proposed method. The logarithmic persion type III was selected as the best distribution of flood. The damage-stage relationship was calculated as well. Based on the uncertinity analysis, the river discharge could be regarded as the major parameter in the uncertainty of EAD.
F. Moradian, N. Ghanavat, A. Nazarpour,
Volume 24, Issue 3 (11-2020)
Abstract
Dusts contain heavy metals such as Pb, Zn, Cu, Cr, Cd and As that can threat human's health and environment. Therefore, the spatial distribution of heavy metals concentration and soil pollution monitoring and environmental quality protection seem to be essential. To assess heavy metals pollution level in Ahvaz street dust, 115 street dust samples were collected from main pedestrians. The samples were analyzed by Atomic Absorption (AAS). The pollution level was estimated based on the geo-accumulation index (Igeo), contamination factor (CF) and the enrichment factor (EF). The average concentration values of Pb, Zn, Cu, Cr, Cd and As were found to be 197.6, 150.1, 179.7, 101, 5.6 and 14.2 mg/kg, respectively. Pearson's correlation coefficient also indicated that Pb, Zn, Cu and Cr had a significant correlation showing similar possible anthropogenic sources. On the other hand, Cd and As showed a lower correlation with other metals, indicating that they belonged to the geogenic sources. The results of contamination factor, enrichment factor and geo-accumulation index also indicated that Pb, Zn, Cu and Cd had a high contamination level. Also, areas with high population density, heavy traffic volume, and industrial activities exhibited a high level of heavy metals contamination.
Z. Ghorbanpour, O. Abessi, F. Kardel,
Volume 24, Issue 4 (2-2021)
Abstract
Drilling material from the tunnel of the Tehran-Shomal highway was estimated to be about 2.5 Million Cubic Meters by the project authorities. Sadly, from the beginning, the drilling materials had been deposited on the open space in the floodplain of the Chaloos river with slightest environmental considerations. During the previous years, weathering and leaching from the drilled materials besides the discharge of drain water from the tunnel had led to seriouse contaminations and the deterioration of the water quality of the Chaloos river. In this paper, the ecological risk of nonorganic pollutants due to drilled materials was investigated. The sampling was done from the excavated materials and river sediment in five different locations throughout a complete year. From the many pollutants, Nickel, Cadmium and Copper were chosen to be investigated. The results showed that almost 15 percent of the samples had a high degree of pollution, while 60 percent of them were clean and the other 25 percent included the highly contaminated ones. All samples were also estimated to have a low to high ecological risk.
B. Khalilimoghadam, A. Siadat, A. Yusefi,
Volume 25, Issue 1 (5-2021)
Abstract
Dust deposited on the leaves of trees can be effectively used as the monitors of polycyclic aromatic hydrocarbons (PAHs). The dust deposited on the leaves can be used as an appropriate index for evaluating PAHs in the atmosphere. This research was conducted to determine the origin and health risk assessment of PAHs accumulated on the leaves of trees in the city of Ahvaz. For this purpose, samples were taken at leaves on 10 points with different land uses including industrial, recreational, high-traffic and residential ones. After preparation, to determine the type and concentration of PAHs, the compounds were analyzed by GC-MS. The results showed that 15 types of PAHs had been identified from 16 important compounds identified by EPA in the dust samples. The concentration of compounds was the range of 3.3-110 microgram per kilogram. The maximum and minimum of PAHs carcinogenic in particles trapped on leaves were in the Kut-Abdolah with 530 ppb and Shahrvand Park Station with 5.13 ppb, respectively. Also, the average relative of LMW/HMW in the aromatics contained in the deposition of particles on trees was 0.5; further the analysis of the main components of aromatic hydrocarbons (PAHs) showed that there was no specific source for these compounds in Ahvaz, and these compounds could be from fossil fuels, urban traffic, natural gas, generally showing a pyrogenic origin.
