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Showing 4 results for Soil Contamination
Biological Removal of Propylene Glycol from Wastewater and its Degradation in Soil by the Activated Sludge Consortia
M Farzadkia, R Rezaee Kalantari, S Jorfi, A.r Talaee, G.r Moussavi,
Volume 2, Issue 1 (7-2009)
Abstract

Background and Objectives : Propylene glycol is the main compound of anti-freezing chemicals. A significant amount of propylene glycol is released to the environment after application and contaminates the soil. The main objective of this study was to determine the biological removal of propylene glycol from wastewater and its degradation in soil by the isolated bacteria from activated sludge process.
Materials and Methods: In the present study, the sludge taken from the return flow in a local activated sludge treatment system was used as the initial seed. The performance of the bioreactor in treating the wastewater was evaluated at four different retention times of 18, 12, 6 and 4 h all with the inlet COD concentration of 1000 mg/L. This phase lasted around 4 months. Then, a part of the adapted microorganisms were transported from the bioreactor to the soil which was synthetically contaminated to the propylene glycol.
Results: The average of propylene glycol removal efficiency from the wastewater in detention times of 18, 12, 8 and 4 h in steady state conditions was 98.6%, 97.1%, 86.4% and 62.2% respectively. Also, the maximum degradation in soil was found to be 97.8%.
Conclusion: According to the results obtained from this study, it appears that propylene glycol is inherently well biodegradable and can be biodegraded in liquid phase and soil after a short period of adaptation.


Evaluation of Geoaccumulation Index, Contamination Factor, and Principal Component Analysis for Estimating Soil Contamination
N Ravankhah, R Mirzaei, S Masoum,
Volume 8, Issue 3 (12-2015)
Abstract

Background and purpose: Soil contamination resulted from either natural or anthropogenic factors reduces environmental quality. The aim of this study was to evaluate the geoaccumulation, contamination factor, and principal component analysis indices to estimate topsoil contamination in Aran-Bidgol town.

Materials and methods: 135 topsoil samples were collected from Aran-Bidgol town and the metal concentrations of Cd, Pb, Ni, Cu, and Zn in each sample were determined. The index of geoaccumulation (Igeo), contamination factor (CF), and principal component analysis (PCA) techniques were applied to determine  the status and trends of soil contamination in this region. The inverse distance weighting (IDW) was then used to map these soil contamination indices.

Results: The research found that the means concentrations of Cd, Pb, Ni, Zn, and Cu were 0.72, 11.41, 29.87, 48.59, and 14.82 mg/kg respectively all exceeded the background values. Mean Igeo and CF of elements followed the order: Cu> Cd> Ni> Zn≈ Pb. The Igeo and CF maps showed higher values of Cd, Pb, and Zn in areas near industrial estates, brick kilns, and urban areas whereas higher levels of Cu and Ni occurred in urban and agricultural areas. According to the PCA index, two principal components were identified that Cu, Ni and Zn were highly loaded in PC1 and Cd and Pb occurred in PC2.

Conclusion: Results indicated that the concentration of Pb and Cd are mostly affected by human activities, whereas Ni, Zn, and Cu contents are controlled by both anthropogenic and natural sources.


Analysis of polycyclic aromatic hydrocarbons in surface soil of agricultural lands in Hamedan, Iran
Azim Rabieimesbah, Soheil Sobhanardakani, Mehrdad Cheraghi, Bahareh Lorestani,
Volume 15, Issue 1 (4-2022)
Abstract
Background and Objective: Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants produced by anthropogenic activities that contaminate all environmental matrices, including soils, and can enter the food chains. Therefore, this study was conducted for the analysis of PAHs compounds content in agricultural soils of Hamedan city, west of Iran, in 2021.
Materials and Methods: a total of 36 surface soil specimens were collected from 12 sampling sites in agricultural soils and after extraction of analytes based on the soxhlet method, the gas chromatography/mass spectrometry (GC–MS) method was used for the determination of PAHs compounds in the samples. Furthermore, soil samples were further analuzed for the amounts of pH, electrical conductivity (EC), and total organic carbon (TOC). Statistical analysis was performed using SPSS software.
Results: Results showed that 16 PAHs (∑16PAHs) total concentrations ranged from 435 to 3292 µg/kg with an average value of 1806 µg/kg. PAHs with higher molecular weight (≥ 4 rings) were dominant in PAHs profiles accounting for 78%. Based on the results, the mean concentrations of all 16 PAHs were lower than MPC established by MHWaS. Furthermore, the mean concentrations of Pyr, B(a)A, Chy, B(b)F, B(k)F­, B(a)P, and B(ghi)P were higher than the MPC established by the Iranian Department of Environment.
Conclusion: Based on the results obtained, as the mean contents of some PAHs were higher than the MPC, therefore, periodic monitoring of soil contamination with PAHs is recommended for the environmental and human health aspects.
 

Identification and determination of amounts of polycyclic aromatic hydrocarbons in the surface soil of Nuruddin Abad in Garmsar
Zahra Lotfi,
Volume 15, Issue 3 (12-2022)
Abstract
Background and Objective: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants with teratogenic, mutagenic and carcinogenic potential, which can pose potential risks to the environment and human health. Therefore, this study was conducted for the analysis of PAHs compounds content in surface soil samples of the disposal site of the wastes resulting from the activity of oil refining units (Nuruddin Abad, Garmsar) in 2022.
Materials and Methods: In this research, surface soil samples were collected from 8 sampling sites in the study area. After the extraction of analytes based on the soxhlet method, the gas chromatography/flame ionization detector (GC-FID) method was used for the determination of PAHs compounds in the samples. Statistical analysis was performed using SPSS software.
Results: The results showed that the concentrations of Naphthalene (Nap), Acenaphthene (Ace), Benzo[b]fluoranthene (BbF), Dibenz[a,h]anthracen (DBA), Benzo[g,h,i]perylene (BP) and Indeno[1,2,3‐c,d]pyren (Ind) were less than the quantification limit of the measurement method <0.01 mg/kg. total concentrations of 16 PAHs compounds ranged from 56.55 to 92.06 mg/kg.
Conclusion: The results showed that the concentrations of Acenaphthylene (Acy), Fluorene (Flu), Phenanthrene (Phen), Anthracene (Ant), Fluoranthene (Flt), Pyrene (Pyr), Chrysene (Chr), Benz[a]anthracene (BaA), Benzo[k]fluoranthene (BkF), Benzo[a]pyrene (BaP) were higher than MPC established by the Iranian Department of Environment. Also, the concentrations of Acy, Flu, Phen, Ant, Pyr, Chr, BaA, BkF, and BaP were higher than MPC established by MHWS. As the mean contents of some PAHs were higher than the MPC, therefore, periodic monitoring of soil contamination with PAHs is recommended for the environmental and human health aspects.
 

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