جستجوی مقالات مرتبط با کلیدواژه "soil pollution" در نشریات گروه "زمین شناسی"

Polycyclic aromatic hydrocarbons (PAHs) are of greater concern among petroleum hydrocarbons due to their toxicity, low evaporation, resistance to microbial degradation, and high tendency to form deposits. Oil spills usually hurt soil biodiversity. Most soils containing bacteria that can absorb high amounts of hydrocarbons may have the ability to reduce aliphatic and aromatic hydrocarbons. Researchers have concluded that soil containing 2-3% crude oil has the highest number of microorganisms compared to typical soils. It is also reported in research that 8 months after soil contamination with oil, oil-degrading bacteria grew 10 times and accounted for about 5% of the soil microbial population. The presence of petroleum hydrocarbons in the soil leads to major changes in its physicochemical and biological properties. For example, with the entry of sewage, the TDS of the soil usually increases, which leads to a decrease in soil fertility. According to Aniagor et al., oil pollution remains in the soil for more than a hundred years. Soil pollution with petroleum substances is considered one of the world's environmental problems. The accumulation of oil pollutants in the environment has caused a lot of challenges because the soil contaminated with these compounds is unfavorable for agricultural, industrial, or recreational purposes, and it is also considered a potential source for polluting surface and underground water. Therefore, this research was conducted to investigate the level of contamination and assess the biological risk of soil to polycyclic aromatic compounds in the Ahvaz oil field using ERL, ERM, and TEF indices.

The current descriptive-applied research was conducted in 1402. The studied area includes the soil of 4 oil centers (an oil exploitation, a desalination unit, an oil rig, and an oil pump house) in the southwest of Iran. Samples were taken from 20 locations within 4 oil centers (5 samples within each oil center) with three repetitions. For this purpose, topsoil was removed from 20 stations in the study area using a grab van with a cross-sectional area of 0.1 square meters using a winch tool from a depth of 10 to 14 cm.

Results of Concentration of PAH in soil samples

The total amount of PAHs among the sampling areas ranges from 9.87 to 2632.688 μg/kg, with an average of 2373.44 μg/kg. The average concentration of compounds with low molecular weight (LMW two and three rings) is 347.152 μg/kg and the average concentration of compounds with high molecular weight (HMW four, five, and six rings) is 60.24 μg/kg. In general, the classification based on the total concentration for PAHs in sediments includes 3 groups: if the total concentration is more than 500 μg/kg as highly polluted, the total concentration is between 250 and 500 μg/kg is moderately polluted and if the concentration is less than 250 μg/kg If it is a kilogram, the pollution is insignificant. Qualitative effects guidelines are also used to correlate effects and total and individual PAH chemical concentrations. Based on this, 30.4% of the stations had very high pollution, 15.17% of the stations had moderate pollution and the rest had low pollution levels.
It was determined that the cyclic aromatic Indene[1,2,3-cd]pyrene (IndPy) with 13.47 has the lowest average PAH and the cyclic aromatic Phenanthrene (Phen) has the highest average PAH with 721.54 μg/kg in the studied area. Also, it was found that Fluoranthene (Flu) and Acenaphthene (Ace) have the lowest ERM. It should be noted that the ERM index could not be calculated for the rest of the cyclic aromatics. Based on the results, Anthracene (Ant) and Acenaphthene (Ace) have the lowest ERL. It should be noted that the ERL index could not be calculated for the rest of the cyclic aromatics. High concentrations of PAHs in soil can have harmful effects on the environment and human health. Due to their lipophilic properties, these compounds are easily accumulated in fat tissues and are transferred to living organisms through the food chain. Studies have shown that some PAHs can be carcinogenic and increase the risk of various types of cancer by causing genetic changes in cells. In addition, the presence of PAHs in aquatic environments can lead to a decrease in water and soil quality and affect aquatic life by affecting biological processes such as photosynthesis and cellular respiration.

Continuous and accurate monitoring of PAH concentration in soils and waters near oil centers is of great importance. This monitoring can help identify sources of pollution and assess environmental risks. Also, the development and implementation of pollution management programs that include the use of cleaner technologies, improvement of wastewater treatment processes, and leakage control can help reduce the pollution load of PAHs. Education and increasing public awareness about the dangers of PAHs and the importance of protecting the environment are also other necessary measures in this field.

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.

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

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.

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.

Today, the pollution of Rangeland soils by various destructive pollutants has become one of the human-environmental problems. Lacking proper management of organic matter discharge can also increase the concentration of salts, heavy metals, and pathogenic microorganisms. In this study, to investigate and measure the concentration of toxic elements, 128 soil samples of Chadegan region were selected to distinguish the concentration extent of these metals and also high-risk and polluted areas. Based on the obtained results in the sampled points, the average soil pollution by cobalt, copper, and chromium elements was observed which its origin can be considered as pollution with a geologic origin. The other elements observed in the soil have little enrichment or no pollution.

Soil pollution as a part of land degradation is caused by the presence of synthetic chemicals or other changes in the soil environment. The heavy metal pollution of soils has been very widespread and there is a risk of transmission of these toxic and accessible metals to humans, animals, and agricultural products. Heavy metals due to their non-degradability and physiological effects on living organisms are also very important in low concentrations. The soil pollution from toxic elements is different from water or air pollution because the toxic elements remain in the soil longer than the other parts of the biosphere and are more durable in the soil. The objectives of this study are to investigate the distribution of toxic elements and to assess the environmental pollution of a part of Chadegan’s soil which has been tried to be studied by using the accumulation land indices, pollution coefficient, pollution load, enrichment coefficient, heavy metals pollution zoning, and the statistical analyses.

In order to conduct this study, in-field inspections, 128 samples from the soil of the studied area have been taken from a depth of 30cm. After doing the initial preparation process, the samples up to the dimensions of less than four millimeters were firstly crushed by using the crusher machine in the laboratory and then pulverized in the disk mill up to 75 microns size (200 meshes). To weigh the samples, Teflon pipes were used in the 4-Acids Digest method.After weighing the samples in a Teflon tube; hydrochloride, pre chloridic, nitric, and chloride acids each added up to a certain amount and then all of them were placed in the Hot Box. After performing the complete digest operation, the samples were cooled at the ambient temperature and reached to sufficient volume with distilled water, and finally, the chemical analysis performed in the ICP-MS method by using Agilent Series 4500 machine made in the United Stutes. Due to the changes in the concentration of the elements in the soil of the region; Ba, Co, Sc, Pb, Y, Cu, B, Zn, Ni, Sr, Cr metals were selected. To determine and construe the extent of pollution of the soil samples studied; the enrichment factor, the pollution load index has been used here due to the concentration of the elements. The ArcGIS software was used to prepare the spatial distribution. Because Kriging methods (normal, simple, and discrete) have high potentials for determining the spatial distribution of the heavy metals of soil; hence they have been proposed as appropriate methods for interpolation and preparing the pollutants map.

The result of calculating the accumulation land index for the soil samples taken from different station show that Igeo extent of all elements is less than one or less than one or less than zero thus have little or no pollution. The result of the pollution coefficient analysis indicates that pollution is law and soil is non-polluted in all sampled areas except for some station that has low and average pollution in terms of cobalt, copper, and chromium elements. Regarding the pollution load index and due to the standard values of P.L.I; the soil of the studied area is free of pollution. The obtained results of calculating the enrichment coefficient of the studied soil samples show that apart from cobalt, chromium, copper, nickel, lead and zinc elements which have average enrichment and its origin can be considered as pollution with anthropogenic pollution; the rest of the present elements have low enrichment and are non-polluted. The zoning map of the concentration of the toxic elements from the area soil indicates that the elements of cobalt, nickel, copper, and strontium in the southwest of the region and also boron, barium, and yttrium elements in the southeast of the area have average to low concentration and the other elements have very low concentration. Based on histogram diagrams, the elements of boron, chromium, nickel, lead, strontium, and yttrium have symmetrical distribution and the elements of barium, cobalt, copper, and scandium have asymmetrical distribution and positive skewness.

According to the result of the accumulation land index, it was found that the studied soils have little or no pollution. The results of the pollution coefficient suggest that except for the elements of cobalt and lead which have average enrichment in some stations, the other elements have poor enrichment. The pollution load index shows that the studied samples have no pollution and also have appropriate concentration and this is while that the enrichment extent of cobalt, chromium, copper, and lead is near average and this enrichment extent can be considered as pollution with an anthropogenic origin.

The Hired mining area south of Birjand, South Khorasan province has been identified as the center of mineral pollution accumulation and it has been attempted to map the soils of the study area from their geochemical and environmental map. The maximum concentrations of Arsenic and Antimony were 5550 and 910 ppm, respectively. The enrichment factor (EF) for Arsenic, Antimony and Cadmium are 1.89, 2.05 and 0.03, respectively. This indicates the average contamination of the two elements Arsenic and Antimony and the lack of contamination of the area with Cadmium. According to the I-geo index, the degree of contamination of Arsenic and Antimony elements was 1, indicating a moderate contamination of the two elements in the region and less than 1 for Cadmium. Pollution Index (PI) for the Arsenic and Antimony elements in the area was moderate and for the Cadmium element, indicating that the soils of the study area were classified as non-polluted to moderately contaminated and most of this contamination is in the adjacent soils of the mine. In general, the soils of the study area have high levels of trace elements (above the natural background value) and if not controlled in the future, the pollution will reach a critical level and cause many problems for the inhabitants of the area.

The farmlands area in the south of Torbate Heydariyeh city has been irrigated by sewage for over 30 years. In this study, the chemical composition and physicochemical properties of soils irrigated by sewage and heavy metal concentration of vegetables cultivated in these soils are determined and compared with unpolluted samples. The polluted soils have a lower pH (7.5- 7.8) and higher organic content (more than 2.3%) than other soils (with pH>8 and organic component < 1%). All soil samples show similar major oxide composition and the same rare earth element (REE) patterns indicative similar parental materials. However, the trace elements composition is completely different between polluted and unpolluted soils. The soils irrigated by sewage show intense enrichment of many elements, especially heavy metals. These soils have lower 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb, 206Pb/207Pb and higher 208Pb/206Pb ratios than other soils which indicate the role of anthropogenic sources in their genesis. The bioavailability values in the polluted soils are very higher than unpolluted samples which led to increasing of transfer factor and heavy metal concentration in the vegetables. The concentration of Cd, Cr, and Pb in the polluted vegetables is more than the maximum permitted concentration.

Today, the Environmental studies on the quaternary regions of sediment are becoming increasingly for various purposes. In this study first Lithological units including the Ophiolite zone of Nosrat-Abad were separated by Remote Sensing. Then, using geochemical data of drainage sediments (350 specimen), in order to better identify the contaminated or exposed areas of heavy metals elements of Nickel , Lead, Zinc, Copper and Molybdenum beginning to preparing maps distribution of pollution index (Igeo) and contamination factor (CF). Also, the method of correlation coefficient and cluster analysis, which is a multivariate statistical method, was used in this study for the statistical analysis of the elements. For this purpose, first developed the appropriate change model theory for each of the calculated indices, the Kriging method was used. In order to identify pollution regions on a local scale, especially high and low density, the inverse weighting method of IDW distance is more appropriate. For each of the indices calculated in this study, the inverse distance method (IDW) was used in the GIS environment and the statistical parameters of SPSS software were used. The results showed that the region of ​​Nosrat-Abad has a high contamination in the presence of nickel in the southeast, and the lead element also has a moderate pollution in the south. As a result of separation the Ophiolite units of the region were identified by Remote Sensing of the rocks with the nature Basic (Gabbros and Basalts) as the source and inclusive Ni and Cu Elements Available in the region.

Extraction of mineral resources and mining can be lead to soil contamination by heavy metals. To determination of the origin of the metals in the sediments in Forumad chromite mine, the sediment samples were taken and analyzed using the sequential extraction method. Analysis of soil samples showed that the concentration of chromium and nickel in sediment is higher than that of global shale. Chromium and nickel in soil distribution map of the region shows that the highest concentration of chromium and nickel in samples from inside the mine tailings deposits of chromite Forumad been harvested according to the average concentration of chromium and nickel in the global shale, the top the amount of chromium in the sediment was attributable to mining activities. Our study shows that Nickel and Chromium with more than 45% concentration are interchangeable phase, which indicating anthropogenic source. Mining activity plays an important role in increasing the concentration of these elements as interchangeable phase. Cd, Pb, Zn and Fe with more than 30% concentration in residual phase, are related to lithogenic source. The results of the sequential extraction method are compatible with the pollution index in the area.