Geological Environment and Engineering
E. Ghadiri Soufi; S. Soltani Mohammadi; M. Yousefi; A. Aalianvari
Abstract
In mining areas, assessing toxic elements (e.g., arsenic) contamination in the soil and stream deposits is a critical issue. It is because mining activities release dangerous elements that enter the environment. In this paper, for modeling the spatial distribution of arsenic contamination in Sarduiyeh-Baft ...
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In mining areas, assessing toxic elements (e.g., arsenic) contamination in the soil and stream deposits is a critical issue. It is because mining activities release dangerous elements that enter the environment. In this paper, for modeling the spatial distribution of arsenic contamination in Sarduiyeh-Baft area, in Kerman Province, across an area of ca. 5000 km2, 1804 stream sediment samples were collected and analyzed. The recommended standard limit for arsenic in soil is 20 ppm, so samples showing arsenic concentration >20 ppm are contaminated samples, which need land reform processes. However, since the number of collected samples is limited, indicator Kriging method was used to identify the possibility of contamination. In the study area, there are 32 known occurrences of porphyry-Cu deposits. Thus, in order to estimate the arsenic contamination in the unsampled locations, indicator kriging method was used. The results indicate arsenic contaminations in north and northwest parts of the study area, which could be occurred by mining of the porphyry-Cu deposits. However, the results show that there is no arsenic contamination in the eastern part although there are several mining sites with high activities.
A.A Nadiri; F sadeghi Aghdam; A Asgharai Moghaddam
Abstract
This study presents an intelligence committee fuzzy logic (ICFL) model to estimate the concentration of total arsenic (III, V) in the area of the Sahand Dam basin, Iran. Because of a high concentration of arsenic (III, V) compared to WHO standard, Geolology Department of Tabriz University and East Azerbaijan ...
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This study presents an intelligence committee fuzzy logic (ICFL) model to estimate the concentration of total arsenic (III, V) in the area of the Sahand Dam basin, Iran. Because of a high concentration of arsenic (III, V) compared to WHO standard, Geolology Department of Tabriz University and East Azerbaijan Regional Water Authority have attempted to sampling and analysis of surface water and groundwater resources in the mentioned area. Hydrochemical parameters Including pH, SO42-, NO3--N, F-, Fe(II, III) and As used as input parameters for Mamdani fuzzy logic (MFL), Larsen fuzzy logic (LSL) and Sugeno fuzzy logic (SFL) to estimate arsenic concentrations. The results in train and test steps showed that all of these models have a similar fitting to the arsenic concentration data in the study area. The ICFL model was adopted to combine the output of the three single fuzzy models instead of the selecting superior single model. To reap advantage of all three models, the weighted combination of the output of fuzzy models used to create a committee fuzzy model. The mentioned model uses particles population algorithm, to obtain weight based on the output of the three fuzzy models to estimate the total arsenic concentration. The results of ICFL model shows, significant fitting improvement compare to individual fuzzy logic models.
SH Safari; A Asghari Moghaddam; A Nadiri; K Siahcheshm
Abstract
Arsenic is one of the most toxic and dangerous soluble substances in natural water. It has long-term ill effects on human health. Arsenic-contaminated water resources have been reported from many parts of the world and Iran, particularly from the Kurdistan province in the west of the country. The aim ...
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Arsenic is one of the most toxic and dangerous soluble substances in natural water. It has long-term ill effects on human health. Arsenic-contaminated water resources have been reported from many parts of the world and Iran, particularly from the Kurdistan province in the west of the country. The aim of this study is to identify the source of arsenic and mechanisms of its release into groundwater resources of the Chahardoli plain aquifers. Groundwater resources in this plain supply much of the water needs for drinking, agriculture and industry. Therefore, 31 water samples were collected from the plain aquifer and chemically analyzed for major and minor ions in the Hydrology Laboratory of Earth Sciences Department of the Tabriz University. Also, the trace elements were analyzed in the Kurdistan Waste Water Organization Laboratory. The results show high arsenic concentrations in the groundwater of the area. The highest arsenic concentration (270 µg/L) is related to a well located in the northwest part of the area which supplies water for agricultural purposes of Delbaran sector. According to the results obtained from multi-variable and graphical methods, there is a meaningful correlation between arsenic and major ions such as Na and K as well as silica, indicating that the source of arsenic is from volcanic rocks. It is therefore a geogenic rather than an anthropogenic phenomenon. The mechanism of arsenic releases into the water can be related to competitive adsorption of dissolved SiO2 in adsorption sites such as oxides of iron, aluminium and manganese.
Y Nazari; A Abbasnejad
Abstract
The Rayen plain, which is about 1900km2 in area is considered as a part of the Lut drainage basin and is located in the southwest of Lut and eastern slopes of the HezarMountain. This plain lies at the 110km southeast of Kerman city. Geographically, it is at 57˚, 13' to 57˚, 54' eastern longitude and ...
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The Rayen plain, which is about 1900km2 in area is considered as a part of the Lut drainage basin and is located in the southwest of Lut and eastern slopes of the HezarMountain. This plain lies at the 110km southeast of Kerman city. Geographically, it is at 57˚, 13' to 57˚, 54' eastern longitude and 29˚, 23' to 29˚, 52' northern latitude. The average height of this plain is about 2600m above msl. Given the location of the plain at the vicinity of the Urmiah- Dokhtar volcanic Belt and considering the role of eruptions as well as volcanic rocks and hydrothermal activities on the concentration of arsenic and the role of this element in environmental problems, this study was performed on the concentration of arsenic in groundwater. In order to determine the variations and source of arsenic, in all,29 samples were collected from the water points (springs, qanats and wells).Subsequently, the concentration of As, major cations and anions(Na+, K+, Ca2+ , Mg2+,Cl-,SO4-,HCO3-), NO3-,F-, as well as EC,TDS, alkalinity and total hardness were determined. Accordingly, isoconcentration map and correlation diagram were prepared and statistical analysis including Principal Component Analysis (PCA) and Cluster Analysis (CA)were carried out. The arsenic concentration in groundwater of this plain varies from 0.1 ppb up to 248.4 ppb with an average of 21.6 ppb. Based on the statistical analysis, arsenic concentration shows positive correlation with pH. The intrusion of hydrothermal waters into the aquifer and desorption from oxides and hydroxides of iron are considered as the main causes of high-arsenic level in some parts of this plain.
A Asghari Moghaddam; L Jalali
Abstract
The KhoyPlain is located in the north of West Azarbaijan province, northwest of Iran. The study area has a cold and arid climate with the annual mean precipitation of about 344 mm. The purpose of this study is evaluating of hydrochemical properties of groundwater and determination of arsenic contamination ...
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The KhoyPlain is located in the north of West Azarbaijan province, northwest of Iran. The study area has a cold and arid climate with the annual mean precipitation of about 344 mm. The purpose of this study is evaluating of hydrochemical properties of groundwater and determination of arsenic contamination at this plain. According to the hydrochemical analysis of 36 collected groundwater samples, in some zones of the area, arsenic contamination is exceed the world health organization (WHO) standard for drinking water. The arsenic concentrations of the water samples were increased in the east and southeast part of the study area. Based on the cluster analysis, the samples were posed in three clusters. Each of the clusters divided into subgroups based on heavy metals contain such as arsenic and iron. There is a positive correlation relationship between arsenic and iron, copper, sodium, chlorine, sulfate and EC. The high correlation of arsenic with iron and copper show the high impact of oxides and hydroxides of these elements in absorbing and accompanying in the sediments and consequently in the groundwater. The most saturation indices of arsenic were for FeAsO4:2H2O and Ca3 (AsO4)2:4H2O compounds, showing that change of saturation indices for these two compounds is similar and increasing from recharge to discharge area. Based on factor analysis method, three main effective factors were distinguished on hydrochemistry of the study area. In the first factor, chlorine, sodium, potassium, arsenic, copper, iron and electrical conductivity are effective elements, which have geogenic origin. Consequently, the origin of arsenic can be geogenicthatis related to geological factors, rocks and sediments that come from alteration of geological formations. Therefore, dissolution of minerals from the Miocene deposits such as marl, shale, sandstone and red conglomerate and the Pliocene conglomerate, and interbedded marl and sandstone are the effective sources of arsenic in the aquifer.
