جستجوی مقالات مرتبط با کلیدواژه "ریسک اکولوژیکی" در نشریات گروه "علوم پایه"

Soil pollution and accumulation of heavy metals in soil are one of the most important environmental issues that threaded the life of plants, animals and humans. Heavy metals due to their toxicity, stability and bioaccumulation are the serious environmental pollutions. This study aimed to evaluate heavy metals pollution of landfill soil of Zahedan city in Sistan and Baluchestan province.Measurement of heavy metals performed in April 2016 at 10 sites based on common standards, by using of random sampling method. 20 composite samples were collected from surface and depth of the soil. After sample preparation, total amount of Chromium, Cadmium, Lead and Arsenic in the soil samples were extracted by nitric acid and for statistical analysis used the SPSS software version 23.The results of ANOVA on samples of the surface and depth of the soil for these elements have been suggested that there is a significant difference at different stations. The results of PLI study showed that the soil of landfill of Zahedan with PLI value less than 2, has low pollution and the highest pollution in surface and depth of the soil is respectively related to station 2 and 1. The results also showed that heavy metals, Chromium, Cadmium, Lead and Arsenic in surface and depth of the soil with Ecological Risk 203.855 and 236.93 respectively which is located in the category of moderate contamination of Ecological Risk.

The aim of this study was to investigate the contamination of deposited dust binding and soil surface (5-10 cm) to heavy metals cadmium, lead and zinc in the prevailing wind direction (North West - South East) Khash city's landfill. First, by observing the status of the current landfill deals and Dust samples of 10 stations in the study area was prepared in January 2013. After preparation of the samples, the concentrations of heavy metals using atomic absorption were measured. Igeo, CF and ecological risk calculated using the formula were determined. The average concentration of cadmium, lead and zinc, respectively, 3.28, 83.1, 1190.65 mg/kg and in soil surface 3.65, 140.71 and 1304.02 mg/kg respectively was achieved. The Igeo index was classified as moderate to severe pollution, pollution factor of very high degree of pollution and ecological risk was significant. The results of data analysis and estimate that 1 almost no pollution control stations and other stations strong have pollution of heavy metals zinc, lead and cadmium.

The aim of this study was to investigate the contamination of deposited dust binding and soil deep (10-25 cm) to heavy metals cadmium, lead and zinc in the prevailing wind direction(North West – South East) Khash city's land fill. First, by observing the status of the current landfill deals and Dust samples of 10 stations in the study area was prepared in January 2013. After preparation of the samples, the concentrations of heavy metals using atomic absorption were measured. Igeo, CF and ecological risk calculate dosing the formula were determined. The average concentration of cadmium, lead and zinc, respectively, 3.28, 83.1, 1190.65 mg/kg and in soil deep 3.98, 114.21 and 1885.32 mg/kg respectively was achieved. The Igeo index was classified as moderate to severe pollution, pollution factor of very high degree of pollution and ecological risk was significant. The results of data analysis and estimate that 1 almost no pollution control stations and other stations strong have pollution of heavy metals zinc, lead and cadmium.

The aim of this study was to measure the concentration of heavy metals (Hg, Cd, Cu, Pb, Ni and V) in marine sediments as well as to determine the potential harmful effects of these heavy metals using Combined Pollution Index (CPI) and Potential Ecological Risk Index (PERI) at seven stations in Chabahar Bay. From each station, 3 samples of surface sediments (0-5 cm) were collected using Van Veen Grab and samples were extracted and analyzed according to the standard methods. The concentration levels of measured heavy metals were in the order of V>Ni>Pb>Cu>Cd>Hg . Contamination assessment based on CPI shows that the sediment samples in the study area were heavily contaminated with the CPI>1 except for Pozm Station. The potential ecological risk indices of Pb, Cu, Ni, were lower than 40, which indicated slight potential ecological risk of all stations. The results showed that the ecological risk level of heavy metals in the sediments of Chabahr Bay were low to very high.

IntroductionStreet dusts are suspended particle matters in the air from different natural and anthropogenic sources that may fall down because of their size and density. The growth of population, industrial activities and vehicles, has recently increased urban systems pollution. Therefore, it has recently been focused on the assessment of street dust contamination as a major source of urban environment pollution, all over the world. Heavy metals in street dusts are among major environmental pollutants that may be originated either from anthropogenic sources such as high traffic loads, industrial activities, building erosions, corrosion of tires and car parts, mineral activities and fossil fuel burnings or from natural sources such as local soil. During recent years huge amounts of atmospheric dust have entered Tehran, crossing national western borders of Iran and settled on the surfaces of urban areas.Assessing heavy metal contents of street dusts which can make serious human health risks seems to be important in this highly populated city. In this study, fifty street dust samples were collected from streets of southern and eastern parts of Tehran, the capital of Iran. The concentrations of nine metals (i.e., Cu, Cr, Pb, Ni, Cd, Zn, Fe, Mn and Li) were determined in samples. Probable natural or anthropogenic sources of metals were identified using multivariate statistical analyses. Enrichment factors and Hakanson’s ecological risk assessment method were also applied.Materials and MethodsFifty locations were selected for sampling. The distribution of sampling points is as follows: ten samples from each Resalat, Baghery and Hengam streets, five samples from Esteghlal Street which are main streets in eastern parts of Tehran. Fourteen samples were collected from the South terminal of Tehran which is located in one of the high polluted areas in the south of Tehran and the last sample was collected from the campus of Iran University of Science and Technology. Dust samples were collected during summer under dry and stable weather conditions, using broom and suction from the edge of pathways in streets and terminal. The samples were kept in special bags and were taken to laboratory. In the laboratory, the samples were air dried at room temperature until they were constantly weighted. Thereafter, they were passed through sieving sets of numbers 10, 35, 60 and 230 (63 µm). The particles with sizes lower than 63 µm can easily become suspended and emitted in the air. Therefore, their entrance into human’s respiratory system and causing serious effects are more probable than larger ones. Dust particles with the size of less than 63 µm were subjected to chemical analyses. Dust samples were acid digested (HCl, HNO3, HClO4). The metal contents of the samples were determined using Atomic Absorption Spectrometer (Buck Scientific model 210 VGP model).By using of Hakanson’s method and RI the ecological risks of each sampling location were calculated. Cluster and principal component analyses were used to identify probable sources of pollutants. In addition, possible effects of human activities on the concentrations of heavy metals were evaluated, using enrichment factor (EF).