فلزات سنگین

The present study was initiated to assess the concentration and contamination level of arsenic, chromium, nickel, copper, zinc and lead in the soils and native plant species around the Foromad mining area (Eastern Meyamay, Semnan province). 15 surface soil samples and 5 dominant plant species were randomly collected from study area and their total concentration of metals along with the physicochemical parameters of the soil samples were measured using standard methods. The mean concentrations of arsenic, chromium, nickel, copper, zinc and lead in the soils are found as 9.90, 1182.5, 697.75, 32.10, 60.73 and 6.51 mg/kg, respectively. The maximum concentration of chromium, nickel and arsenic was measured in the mining area where the extracted mine wastes are piled. Based on the calculated geochemical indices (enrichment factor, geoaccumulation factor and pollution load index), the soils of Foromad mining area are heavily contaminated in terms of chromium and nickel. The results of multivariate statistical methods (correlation analysis and principal component analysis) indicated that chromium, nickel, arsenic and copper were derived mainly from anthropogenic sources. The calculation of source proportion of metals in the soils also confirmed that more than 70% of nickel and chromium, 67% of arsenic and 53% of the copper contents are roughly contributed from the anthropogenic sources. Comparing the average concentration of heavy metals in plant samples with their corresponding toxic ranges in plants also showed that chromium, arsenic and lead are within the safe and the normal range, respectively, while copper and zinc are within the toxic range and nickel metal is far beyond its toxic range. Based on the calculated biogeochemical indices (BCF and TF), Artemisia species among others can be considered as a potential candidate to remediate the nickel-contaminated soils.

The present study aims to evaluate the concentration, level of pollution, source, and health risk induced by heavy metals and microplastic particles in the agricultural soils of the Gorgan city suburb. For this purpose, 21 topsoil samples (0-30 cm) were collected. Soil’s physicochemical parameters, concentration of heavy metals, and the quantity and general characteristic of microplastic particles (were investigated using standard methods. The obtained results show that the texture of the samples is clay-sand loam and sandy loam. pH of the samples is slightly alkaline to moderately alkaline, the average contents of carbonate and organic matter are 19.8 % and 1.2 %, respectively, and the average cation exchange capacity of the samples is 18.7 meq/100g. While the average concentration of Cu, Zn, Cr, Mn, Co, Fe, Ni, and Sb are higher than the world soil average composition, the average contents of As, Pb, and Cd are comparable or lower than the standard values. Human health risk assessment shows that among the studied elements, Cr has the highest carcinogenic and non-carcinogenic risks through ingestion, inhalation, and dermal contact routes, for both children and adults. Microplastics are present in all soil samples in the form of fibrous, pellet, fragmental and spherical, and and most particles are bigger than 1000 μm. FT-IR analysis indicates that micrometers are polymers that are mainly composed of polyethylene, pointing to the agricultural source of microplastics particles. The results of this study show that agricultural activity is the most important source of soil pollution in the suburbs of Gorgan city and can induce health risks to the residents of the study area.

Contamination of soil and sediments with heavy metals causes the destruction of organisms in ecosystems.The Sources of sediments and soil of Jovein plain from ophiolites. Therefore, it is important due to the existence of geogenic pollutants, especially chromium and nickel . In this study, some indicators of heavy metal pollution in the soil and sediments, were evaluated .The purpose of this research was to evaluate the degree of soil and sediment pollution. 107 surface soil samples were collected from the depth of 0-30 cm and sent to the laboratory for analysis. Soil samples were digested by 4 acid method and the concentration of the heavy metals was measured by the ICP-OES device. Results showed that the metal pollutants could be classified into two groups. The first group includes nickel and chromium, which are 6 and 3 times higher than the average shale values in all samples, respectively. The second group, which includes arsenic, cobalt, copper, lead and zinc, is almost equal to the global average of shale. The western side of the plain has low level ofpollution. Most likely, the cause of environmental geochemistry abnormality can be chromite mines and its processing activities, which are located in this area. The northern area of the ferrochrome factories, the sugar and citric acid factories of Jovein, which are downstream of the above industries, is very high in terms of the possibility of toxicity to heavy metals with a high risk level, and also the percentage of possible toxicity is between 50-75%.

The abandoned kaolin mine under study is situated near Rahatabad village in the southwest of Naein county, Isfahan province, Iran. Samples were collected from the brine and efflorescent salts of two ponds formed by excavation in the mine, and the pH, Eh, and heavy metals concentration in the samples were determined. Efflorescent salts were identified via XRD analysis after being separated by color. Minerals found in the efflorescent salt samples include tamarugite, rhomboclase, szomolnokite, metasideronatrite, gypsum, ferricopiapite, magnesiocopiapite, bloedite, and konyaite. Cu, Mn, Ni, and Co are concentrated in bloedite and konyaite minerals, Cu, Mn, and Zn in kopiapite group minerals, Cu, Mn, and Co in szomolnokite, Pb and Zn in gypsum, and Zn and Mn in rhomboclase. Enrichment factor calculations indicate that Cu has extremely high enrichment, Co and Ni have high enrichment, while Pb, Mn, Zn, and Cd have low enrichment in the efflorescent salts. Moreover, all heavy metals exhibit very high enrichment in the efflorescent salts compared to the brine. With regards to the Pollution Load Index (PLI) in the efflorescent salts, the yellow and gray efflorescent salts are categorized as contaminated, while the other samples are non-contaminated. The Geoaccumulation Index (Igeo) categorizes the samples as highly to heavily contaminated for Cu, slightly contaminated for Co, not contaminated to slightly contaminated for Ni, and non-contaminated for the other heavy metals.

This study aims to investigate the content, geochemical speciation and mobility of heavy metals as well as mineralogical characteristics of wastes in a coal washing plant (Alborz-e-Sharghi Company). The obtained results revealed that coal wastes as compared to world coal mean are normal to enriched in terms of Pb, Cu, Ni, Cr and As while are depleted with respect to Cd and Zn. XRD analysis indicated that quartz, kaolinite, illite, calcite, calcite, siderite, gypsum and pyrite are present in the studied samples. The results obtained from speciation analysis showed that Pb, As, Cu, Ni and Cr were mainly associated with phases 6 and 5 (sulfide and silicate bound fractions) while Zn and Cd were mostly retrieved from phase 1 (water soluble fraction). The mobility factors also confirms that Zn and Cd with 53.32 and 44.12 % are the most mobilizable elements. This is particularly prominent for 30 years aged coal wastes. This study generally concludes that most mobilized metals such as Zn and Cd have the high potential to find their ways into the surrounding environments and this should be considered in future assessments and management of coal waste produced in the study area.

Urmia Lake, with more than 51,000 Km2 area​​, is one of 6 main Iran’s catchments. Nazluchai, Shaharchai, Bazandozchai, Gadarchi, Mahabadchai and Siminehroud located in west and southwest of Urmia Lake are among the most important rivers supplying the lake. This study aims to evaluate heavy metals health risk including cadmium, lead, nickel, cobalt, arsenic and chromium in surface sediments of western and southwestern rivers of Urmia Lake, for which 22 sediment samples from depth of 0-10 cm was randomly taken and after analyzing by ICP-OES method, non-carcinogenic risk for all studied elements and carcinogenic risk for elements with definite carcinogenicity (cadmium, nickel and chromium) were calculated. According to results, the highest concentrations of nickel, cobalt and chromium were recorded in Baranduzchai and Gadarchai, the highest arsenic concentration was recorded in delta and downstream of Nazluchai and Mahabadchai and the highest cadmium concentration was recorded in Nazluchai delta and downstream of Siminehrood. In mentioned cases, heavy metals concentration is much more than the other parts. Average daily doses of studied heavy metals for children and adults were measured as follows: cadmium <lead <arsenic <cobalt <chromium <nickel. Results also showed that the highest non-carcinogenic risk for children was related to cobalt, chromium and nickel, respectively, while non-carcinogenic risk of cobalt (0.51) and chromium (0.215) is close to the threshold. The overall risk (HI) of all studied heavy metals for children is also close to threshold. Total risk of chromium and cobalt is close to the threshold in 5 and 4 samples, respectively, and in only one sample located in downstream of Baranduzchai, total risk of cobalt has exceeded threshold value. Carcinogenic risk of cadmium and nickel in studied samples does not threaten human health, while carcinogenic risk of chromium is close to threshold and consequently total carcinogenicity risk is close to threshold.

Mining is a necessary activity for the development of countries, but it imposes direct and indirect negative impacts on the exploited areas and their surroundings. Sangan iron mine is one of the largest iron ore deposits in the Middle East, where the ore is extracted by open pit mining. The present study aims to investigate the soil’s concentration of heavy metals and to assess the level of soil’s contamination in the Sangan mining area. For these purposes, 44 samples of the soils (including both topsoils and subsoils) of the Sangan mining area were collected, and were analyzed by an ICP-MS device. The obtained data were analyzed by calculating the geochemical indices and statistical methods. On the basis of descriptive statistics of the analytical data, Pb with an average content of 138.39 mg/kg and Cd with an average concentration of 0.19 mg/kg had the highest and lowest concentrations in top soils, respectively. Moreover, Cr with an average value of 102.19 mg/kg, showed the highest, and Cd with an average of 0.2 mg/kg showed the lowest concentrations in subsoils. The average concentrations of As, Cr and Fe in the study area were higher than their respective values in the World-Soil Average composition. Among the elements, Pb had very high and severe enrichment in two stations with enrichment factor values of 149 and 23.85. The results indicated no severe soil pollution and ecological risk in the study area, except in some sampling sites. The most polluted soils were collected near the placer extraction units and tailing ponds of Ehya-Sepahan Company, as well as the waste rock pile of Sanabad Comprehensive Development Industrial and Mining Company.

The infiltration of leachate resulting from waste disposal into the ground and reaching the groundwater aquifers leads to the pollution of groundwater resources. Considering the importance of water resources in the critical situation of Iran, it is necessary to carry out serious research to protect the existing resources. This research is a case study to simulate the process of leakage and transfer of leachate from landfill to groundwater and the spread and migration of four heavy metals (lead, iron, zinc and cadmium) in the unconfined alluvial aquifer of Babolsar city. The 5 ha landfill investigated in this study receives 150 tons of solid waste per day from Babolsar city. Infiltration and transfer of leachate to this aquifer is simulated using finite difference technique and MODFLOW, MT3DMS codes in GMS software. After the implementation and calibration of the quantitative model, the qualitative model was implemented for four heavy metals (lead, iron, zinc and cadmium). By applying the processes of convection, hydrodynamic dispersion and absorption, the natural cleaning potential of each element was investigated and the qualitative model of pollutant transport was calibrated and the amount and rate of absorption in the studied range were determined for each element. Based on the simulation results, the structure and geological material have had the greatest impact on the transfer of leachate from municipal solid waste in the traditional landfill in Babolsar. Due to their low permeability and high capacity to absorb contaminants, clay and organic matter in the soil of the studied area have prevented the transmission and spread of pollution plume in the alluvial aquifer of Babolsar. In order to predict the potential of natural cleaning of the aquifer in the coming years and determine the fate of these elements, the graph of changes in the concentration of these elements until they reach the standard allowed concentration was drawn with respect to time and the equation for each element was determined. The cleaning equations obtained from the qualitative model are a suitable tool for predicting the development of the pollution plume in the aquifer and determining the natural changes in the concentration of these elements with time for the optimal management of the aquifer in the hands of experts.

Burial of urban waste is one of the main problems of the current century. To the extent that it has affected the vital resources of human life. Langrod City in Gilan province, like any other city in the world, is involved in the problem of urban waste. Failure to set up the compost plant of this city in the Atakor region has caused a huge amount of waste to be stored and the infiltration of toxic leachate for more than a decade and many problems for the residents. The purpose of this study is to investigate the pollution status of Quaternary soils in the region. The method of this study is based on eight pollution indices including land accumulation index (Igeo), enrichment factor (Ef), modified pollution degree (mCd), pollution factor (CF), pollution load index (PLI), toxic risk index (TRI). , modified hazard quotient (mHQ) and potential environmental risk (RI). The results show that the quaternary soils of the region are contaminated with heavy metals. Both earth-born and man-born factors have played a major role in these pollutions. Erosion of metamorphic units is the main factor in the accumulation of some heavy metals in the form of ground deposits. The location of the waste depot can be considered the only man-made factor of pollution in the region. It should be noted that, except for the two metals lead and zinc, the contribution of man-made pollution is much lower than the earth-made factor. Setting up a compost factory and building a sewage drainage network can have a significant impact on reducing the rate of pollution.

The Persian Gulf is an incredibly important and sensitive ecosystem that has garnered increased attention in the 21st century due to ongoing changes in international relations. There is an evident need for marine geological studies in this area, given the development plans, limited understanding of the seabed's geological condition, abundant oil resources, environmental concerns, and pollution of potentially toxic elements along the Persian Gulf's shores. The Persian Gulf holds a significant global importance as a water body with a delicate ecological balance. Given the sensitivity of the Persian Gulf and the detrimental impacts it endures from diverse polluting industries, environmental monitoring of this region is essential. This study presents a comprehensive analysis of geochemical changes, origin, and environmental and ecological risk assessment of potentially toxic elements in 140 sediment samples collected from the Iranian waters of the northeastern Persian Gulf.

We examined 140 surface sediment samples collected from varying depths of the waters under Iran's jurisdiction in the northeastern Persian Gulf during the MG-PG-2008 cruise. Our goal was to assess the level of contamination and ecological risk posed by elements such as As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, V, and Zn. The concentrations of these elements in the sediment samples were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to provide a comprehensive understanding of their presence. Additionally, we quantified the pollution intensity in the sediments using indicators such as the geo-accumulation index (Igeo), enrichment factor (EF), and modified degree of contamination (mCd). Furthermore, we evaluated the ecological risk of potentially toxic elements in the sediment samples based on the potential ecological risk index (RI) and determined the toxicity risk of trace elements using the toxic risk index (TRI).

The sediment samples indicate significant enrichment of elements such as As, Cd, and Mo. Elements like Fe, Pb, Ni, Cr, and Mn fall into the medium enrichment category, while Cu, Zn, Ba, V, and Co are classified as having low enrichment. Comparatively, Fe, Ba, V, Zn, Pb, and Cu in the sediment samples show lower concentrations than their corresponding values in the upper continental crust. The enrichment factor (EF) values for these elements are less than 1.5, suggesting a terrestrial source for these elements. Additionally, the modified degree of pollution (mCd) values indicate very low levels of pollution at almost all stations.The ecological risk evaluation of potentially toxic elements in the surface sediments of the northeastern Persian Gulf reveals that Cd poses a medium ecological risk, while other elements exhibit a low ecological risk. The overall average ecological risk potential index (RI) at all sampling stations indicates a low level of ecological risk. Cd has the greatest influence on the ecological risk potential index, accounting for 61% of the total index, followed by As with 27%. The average toxicity risk index (TRI) suggests no toxicity risk, with Nickel being the most influential, contributing 52%, while Chromium has a 19% share.Notably, the significant enrichment of As and Cd in the northeastern Persian Gulf suggests their predominantly anthropogenic origin. This high concentration of arsenic may stem from the release of wastewater from urban and agricultural sources, various industries, gas and oil fields, and dust particles. Likewise, the presence of cadmium can be attributed to sources like oil tankers' transportation and industrial wastewater from factories.The significant correlation between aluminum, nickel, chromium, and vanadium (Al, Ni, Cr, V) indicates their terrestrial origin, mainly attributed to riverside erosion, weathering, and atmospheric precipitation. While the average enrichment of chromium and nickel can be linked to their high natural concentrations in the soil of southern Iran, industrial processes, including oil refining, can also contribute to their sediment concentrations.

The ecological risk assessment indicates medium-level risk for cadmium and low-level risk for other elements. The overall average potential ecological risk index (RI) suggests a low level of ecological risk across all sampling stations. The average toxicity risk index (TRI) indicates no toxicity risk, with nickel contributing the largest share (52%) followed by chromium (19%). Chromium and nickel concentrations in sediments are primarily of geogenic origin, evidenced by their strong correlation with aluminum. The average enrichment of these elements is attributed to their high natural concentration in the soil of southern Iran, although some man-made sources also contribute. The significant enrichment of As and Cd in sediments suggests their predominant human origin, possibly from wastewater discharge, industrial activities, and oil and gas fields. Cadmium in the Persian Gulf may originate from anthropogenic sources such as oil tanker transportation and industrial wastewater discharge.

In the last few decades, pollution caused by heavy metals in groundwater sources has been recognized as a major environmental problem. In this research, the ability of clinoptilolite zeolite as a low-cost adsorbent for the removal of heavy metal ions specifically lead, cadmium, and cobalt (which have a higher concentration than the permissible limit of drinking standard indicators in the Varamin region) in continuous absorption systems was investigated. XRD, XRF, ICP-MS, BET, and FESEM tests were carried out to check the characteristics of the absorbent materials, to determine the crystal structure, type, and percentage of minerals, and to check the concentration of elements. Equilibrium sorption studies were carried out using discontinuous experiments to analyze the sorption capacity of clinoptilolite. Langmuir and Freundlich adsorption models were fitted to the data and the effect of the initial concentration of the solution at different pH was determined using adsorption experiments to validate the measured data, fitting statistical parameters such as root mean square error (RMSE) and regression coefficient (R2) were used and the Langmuir model showed a better fit to the absorption data of the above elements. In continuous experiments, the height of the fixed layer of clinoptilolite was 40 cm, the column diameter was 4 cm, the particle size was 0.42 to 0.84 mm, and the volumetric flow rate, was 1.65 ml/min. The breakthrough curves generated fromthe laboratory data were in good agreement with the Thomas model and Yoon-Nelson model. This research demonstrates that clinoptilolite can be an effective adsorbent for the removal of heavy metals such as lead, cadmium, and cobalt and has the potential to be used in the development a new in-situ remediation approach for the removal of these metals from polluted groundwater.

In order to investigate urban soil areas of Isfahan for heavy metals, in the summer of 2022 from 23 sampling stations and after preparation, the samples were chemically analyzed by ICPOES method with 4-acid digestion. The soil accumulation index shows that CdA metals have a large consumption rate. The results of the enrichment factor of all metals indicated that the origin of all the metals except Pb, Cd, and As studied in the soil of urban areas was terrestrial and their accumulation was terrestrial. The pollution factor results showed the highest pollution factor for Pb and Cr metals. The results of the pollution load index showed that 8 samples have pollution and 15 samples have no pollution in the soil of the urban areas of esfahan. The results of the study of ecological risk and environmental risk of heavy metals showed that all the studied samples, except for 9 samples for Cd metal and 1 sample for Pb metal, have low ecological risk. Also, the findings of the study of the environmental risk index according to the values obtained for the soil of the urban areas of Isfahan showed that the environmental risk of heavy metals is low. According to the results, it was found that the risk potential of heavy metals in the soil of the studied areas to cancerous and non-cancerous diseases is higher in children than in adults.

The aim of present work is the assessment of source of heavy metals,and polycyclic aromatic hydrocarbons in the dust streets of Mahshahr city. Samples were collected from areas with different utility (e.g., industrial, commercial, educational, high traffic, hospitals, residential, and park). Heavy metals concentration like, Sb, Pb, Zn, Cu, Co, Cr, Mn, Ni, Mo, V, Fe and PAHs were measured using ICP-OES and GC-MS analyses; respectively. The average values of enrichment factor for Fe, Cu, Zn and Pb is intermediate. Calculation of geoaccumulation index (Igeo) indicate that heavy metals such as Fe, Cu, Zn and Pb in the dust samples belong to contaminated to medium contaminated categories, while other heavy metals (i.e., Co, Sb Cr, Mn, Ni, Mo, and V) belong to uncontaminated class. Statistical analyses such as principal component analyses (PCA) and clustering analyses (CA) was used to assess the natural and/or anthropogenic origin of pollutions. The results of these analyses indicate that heavy metals and polycyclic aromatic hydrocarbons mostly originated from anthropogenic sources, owing to the presence of petrochemical industries, and vehicles traffic. PAHs with high molecular weight (HMW) are dominant in all selected dust street samples. Also, it is confirmed that PAHs in dust have a pyrogenic origin. Importantly, the sum of carcinogenic PAHs in all sampling sites is higher than sum of non-carcinogenic PAHs. The ratios of IND/(IND+BghiP) vs. (BaA/(BaA + Chr) proved that biomasses, together with oil and coal combustion could be considered as the source of PAHs in the dust street samples of Mahshahr.

This research was conducted in order to evaluate the level of heavy metal contamination of the soils in the vicinity of the Yellow Flower lead and zinc mine. For this purpose, heavy metals of 33 surface soil samples of the mining area were analyzed with AAS flame atomic absorption spectrometer. The indices of origin and determination of the degree of pollution including enrichment index (Ef), accumulation index (Igeo) and pollution index (Cf) were calculated to evaluate soil contamination with heavy metals. According to the results, the average concentration of heavy metals including scandium, arsenic, yttrium, cadmium, copper, nickel, vanadium, chromium, lead, barium, manganese and zinc are 20.93, 28.19, 35.84, 56.2, and 90 respectively. 63/69, 71/69, 141/39, 176/39, 197/22, 404/87, 475/55, 492/27 mg/kg, where zinc is the highest and scandium is the lowest. Also, the results showed that the studied area has no general pollution with heavy metals. The concentration of some heavy metals such as lead, zinc and cadmium is very high in some places, which has caused the soil pollution to increase. This issue is due to the type of minerals in the mining area, including sphalerite and galena

The present study aims to determine the concentration of heavy metals and toxic metalloids in rice of Sari paddy fields in the Mazandaran province of Iran. In this study, sampling was performed from 32 stations of the rice seed section. The soil-plant relationship was investigated in 6 stations using samples taken from rice soil and other plant parts such as roots, stems, leaves, and bran. Soil and plant samples were prepared using ICP-OES and ICP-MS methods, respectively, and then analyzed chemically. The results of the chemical analysis of rice samples showed that the mercury (Hg) concentration is usually about 0.07 ppm. However, it reaches about 0.09 ppm in some points (30% of the samples). The mean concentration of lead (Pb) is 0.91 ppm, which is close to its allowable limit. In some samples, elements arsenic (As), cadmium (Cd), nickel (Ni), and zinc (Zn) are different from normal concentrations. The study results attribute the origin of lead elements to the use of chemical zinc fertilizer in rice fields and paddy fields, as Pb concentration in areas with zinc (Zn) fertilizer consumption is about 3.99 ppm. The as concentration in Isa Khandagh is 1.15 ppm, suggesting a high deviation from the normal level. In addition, the concentration of trace elements in rice crops in different regions of Sari city compared with rice crops in some foreign cities shows a high correlation for chromium (Cr), cobalt (Co), Arsenic (As), magnesium (Mg), manganese (Mn), sodium (Na), and Zinc (Zn).

Considering the development of industry and technology, the accumulation of inviromental contaminants,especially heavy metals in the soil led to increasing concern about food security.The aim of  this study was to investigate the concentration of heavy metals in the surface soils of agricultural lands south of Bardaskan located in Khorasan Razavi. The soil samples were taken from depth of 10 to 30 cm soil by filed assessment.The dominant soil texture is gravelsandy and PH 7.3 and subalkaline. Mean total concentration of Cd,Cu,Mn and Mo were0.66,251,2176,6.67(ppm).The highest values of Igeo,EF and CF indicators were found for Cu(0.6),Mo(6.26) ,Mo(4.44).Pollution index calculated using the average of total CF was 2.36,indicating the medium contamination class in the area. High concentration of heavy metals Cu,Mo,Mn and Cd in the south of Bardaskan can be a threat to agricultural land in this area. geological structures such as faults, and human activities such as mining, agriculture, and industry can provided the necessary grounds  for soil  contamination with heavy metals and increase the concentration of heavy metals in the agricultural soil of the region. Monitoring the pollutants concentration in the agricultural soils as well as in agriculutral products is essential to conserve natural resources and ensure the food security.

In this study, in order to investigate the contamination of surface sediments in west and southwest rivers of Lake Urmia, 20 surface samples were taken from a depth of 0-10 cm. After passing the samples through a 2 mm sieve, the total amount of heavy metals was obtained by ICP-OES. Then the geo-accumulation index (Igeo), enrichment index (EF) and pollution index (PI) of metals was calculated. Based on the results, geo-accumulation indices of nickel, cobalt, chromium, arsenic and cadmium in all sediments are in the risk range of extremely high (1<I_geo<2) or high (I_geo>2). Nickel enrichment coefficient in Barandozchai and Gadarchai sediments is extremely high (EF>40) and in Shahrchai, Mahabadchai, Nazluchai and Simineh rivers in very high pollution range (20<EF<40). Arsenic enrichment coefficient in all sediments shows very high pollution. The enrichment index for cadmium, copper, cobalt and chromium indicates high pollution in almost all rivers and it is moderate to high for zinc. Arsenic shows the highest average for contamination index in Nazluchai deposits. Statistical correlation matrix shows the highest correlation between cobalt and chromium with nickel because of their common geogenic origin and the significant correlation between nickel and sand indicates the natural origin of the element. The correlation between zinc and organic matter and clay is significant and probably due to zinc uptake by clay and organic matter. There is a significant relationship between arsenic and cadmium. Principal component analysis indicates 4 sources for the studied heavy metals, the first 4 components with specific values higher than 1, determine more than 85% of data variance. In the first component, nickel and chromium along with sand have the highest weight. Zinc and copper are in second component along with pH, cadmium and arsenic in third component and organic matter and lead in fourth component have the highest weight.

This study was conducted to investigate the heavy metal contamination and their region in Jafar Abad, southwest of Kashmar in Khorasan Razavi province. For this purpose, heavy metals of surface soil samples 32 (10- 30 cm) were analyzed in the Jafar Abad, southwest Kashmar by ICP-MS origin indices and degree of contamination including enrichment factor (Ef) and its percentage, geoaccumulation index (Igeo), contamination factor (Cf) were calculated to evaluate soil contamination. Based on the results, in between heavy metals, Manganes has the highest and Cadmium the lowest average contamination. Maximum and minimum enrichment factors are also Molybdenum and lead respectively. The results show that the study area is almost contaminated with respect to copper and molybdenum metals. The results of this study indicate that heavy metals contamination is lithogenic and mainly due to the lithology of the region such as shale, sandstone, conglomerate, gypsum marls, granite and volcanic rocks, and anthropogenic contaminants, except from limited mining activities and some agricultural activities did not play a significant role in the contamination of this region. Based on cluster analysis and principal component analysis, the presence of some metal such as copper, molybdenum and manganese together indicates their common origin.

The aim of this study is to determine the ambient concentration, content of heavy metals and morphology and mineralogy of PM2.5 samples collected from air pollution monitoring station in Haft-Tir square (central Tehran). For this purpose, PM2.5 samples were collected by means of low-volume sampling device during five months (April-August 2019). Based on the obtained results, there is more loading of PM2.5 on June higher that 10 μgm−3 and showed high to very high pollution level. Variations in metal concentration in the sampling months were relatively similar, showing order of Zn>Ni>Pb>Cr>Cu>Cd. Comparing the mean concentration of metals with international permissible limits the concentration of Pb and Cr in PM2.5 samples was lower than that of recommended by the WHO while the average concentration of Cd and Ni was higher than those of USEPA recommended limit. Calculations of enrichment factor and results of principal component analysis revealed that Cr is of geogenic origin, Cd and Zn are derived from anthropic sources and Pb, Cu and Ni are probably of mixed sources. Based on scanning electron microscopy images, PM2.5 are observed as a shapeless or irregular, rod-shaped, irregular spherical, completely spherical, sheeted, as well as long chain aggregates or single crystals. According to the results of X-ray diffraction analysis, clay minerals, quartz and calcite were found as major minerals, gypsum and dolomite minerals were identified as minor minerals and wüstite and halite minerals were identified as rare mineral phases.

The study area is located in Chaharmahal and Bakhtiari province and includes Shahrekord and its villages. The highest outcrop of the region is related to the Mesozoic limestone formations in which the Upper and Lower Cretaceous limestones have the largest extent, and Precambrian sediments have a limited extent. The existence of different age facies along with mining, industrial, and agricultural activities can provide the necessary grounds for soil contamination with heavy elements. In the present research, considering the importance of soil health from the perspective of environmental geochemistry, the presence and distribution of these elements in the region’s soil were investigated. The present study aimed to determine the distribution of heavy metals based on zoning maps of elements and the correlation between them in the soil environment.

For this purpose, the results of the chemical analysis of 61 soil samples were taken from a depth of 0-25 cm (after removing surface contaminants). The concentration of heavy metals was analyzed using the ICP-MS method in Zarazma Company and was evaluated and interpreted using multivariate statistical methods. Also, geoaccumulation index (Igeo), Nemerow integrated pollution index (NIPI), pollution index (PI), and enrichment factor (EF) of elements were calculated.

The average concentration of total heavy elements in the soils of the study area was 4.39, 13.34, 91.82, 32.18, 70.57, 11.70, and 81.64 for arsenic (As), cobalt (Cb), chromium (Cd), copper (Cu), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn), respectively. The average concentration of heavy metals in the surface soil of Shahrekord for different elements was in the following order: As

Therefore, there is no significant environmental concern. This result is in line with the results of the present study. In all sampling sites, the PI is in the allowable category. Besides, the concentration of heavy metals such as Pb, Zn, and Cu is less in the soil of Shahrekord than in the soil of other cities, but Ni has a higher concentration. Also, since the EF was less than 10 for the study area’s soils, these elements’ natural or geogensis origin is confirmed