JWSS - Journal of Water and Soil Science

To assess the effects of different levels of soil lead on mineralization of organic carbon and nitrogen, a factorial pot experiment was conducted using litter bag method. The factors examined were different levels of soil lead (0, 25, 50, 100, and 200 mg kg^-1soil) and incubation periods (1, 2, 3 and 4 months) in three replications. At the end of incubation periods, the litter bags were pulled out of the pots and the weights of plant residues remained in bags were measured. The plant residues were also analyzed for organic carbon and nitrogen. Organic carbon and nitrogen losses were calculated by subtracting the remaining amounts of organic carbon and nitrogen in one incubation time interval from those of former one later incubation time interval. The results showed that the losses of organic carbon from wheat residues and carbon decomposition rate constant decreased as the levels of soil lead increased over than 25 and 50 mg/kg of soil respectively. The losses of organic nitrogen was more affected by lead pollution and decreased as the levels of soil lead increased, but nitrogen decomposition rate constant decreased as the levels of soil lead increased over than 25 mg/kg. The losses of organic carbon and nitrogen in 200 mg Pb/ kg of soil were 3.2 and 11.7 % lower than control treatment. The results of this research indicate that contamination of soil by lead increases residence time of organic carbon and nitrogen in soils and slows down the cycling of these elements.

Siderophores are low molecular weight iron-binding ligands produced by aerobic soil microorganisms and some plants roots. They may also develop complexes with other metals such as Cd, thereby influencing the bio-availability, toxicity and mobility of Cd in the soils and aqueous environments. The main objective of this study was to investigate the effects of desferal siderophore (DFOB) on the adsorption of Cd on muscovite. The adsorption of Cd on muscovite was studied as a function of pH (Cd concentration: 5.0 mg L^-1) in the range of 3.0-8.0, as a function of metal concentration (Cd concentration in the range of 1.5-10.0 mg L^-1); this was done in the absence and presence of siderophore (DFOB concentration 250 μM) using a 24h batch equilibration experiment. The results of pH dependent experiments showed that the siderophore deceased the adsorption of Cd onto muscovite at pH ≥5. The results of the isotherms experiments also showed that the removal of Cd from solution was affected by siderophore in all equilibrium concentrations of Cd at both pHs. Siderophore decreased the adsorption of Cd by the mineral. The Freundlich and Langmuir isotherms described the equilibrium data satisfactorily. The values of Freundlich (K_F) and Langmuir (K_L) bonding constants were greater in the suspensions without siderophore, as compared to those containing siderophore, thereby indicating the low adsorption affinity of Cd on muscovite in the presence of the siderophore.

The purpose of this research was to study the effects kerosene by a factorial experiment in the nested design in three replications. The factors included region (Shush, Dezful and Bavi), plant (parsley, dill, coriander and carrot), and management practice (control, contaminated field with kerosene 1, contaminated field with kerosene 2). Heavy metals concentration (Pb, Zn, Cu and Cd) was measured in soil (DTPA extraction method) and plants samples. The results indicated that the average values of the heavy metals concentration in both soil and plants samples subjected to kerosene contaminated treatments were greater than those of the control treatment in all of the regions. The Bavi region had the highest Cd (14.29 in soil; 11.9 in Dill) and Pb (40.46 in soil; 35.53 in Coriander) and the lowest Zn (34.75 in soil ; 28.44 in Carrot) and Cu(22.30 in soil; 16.96 in Carrot) concentration values in  both soil and plants subjected to kerosene contaminated treatments. Also, the lowest concentration values of Cd (9.33 in soil; 8.01 in Carrot) and Pb (30.36 in soil; 23.54 in Carrot) and the highest values of Zn (109.08 in soil; 86.33 in Dill) and Cu (47.71 in soil; 38.57 in Dill) were recorded in Shush and Dezful regions, respectively. Based on these findings, kerosene usage could lead to a significant increase in the heavy metals (Cd, Cu and Pb) uptake, exceeding the critical level for the vegetables. This might increase the transformation risk of the mentioned heavy metals in the food chain
 

In this study, the distribution of heavy metals pollution including arsenic, antimony, nickel, copper, cadmium, cobalt, bismuth, lead and zinc in the stream sediments of Zarshuran- Aghdarreh area was investigated by using statistical techniques and the geometric integration of each sample basin. For this purpose, the degree of pollution in 154 stream sediment samples was analyzed and the distribution maps for enrichment factors were prepared by using a combination technique, pixel estimation, and statistical and geostatistical methods. The results of calculating the enrichment factors indicated that the higher enrichment was related to arsenic, antimony, bismuth, cadmium and lead. Furthermore, the concentration of zinc, copper, lead, arsenic, antimony, cadmium and bismuth in the stream sediment samples was higher than the global average. Application of the principal component analysis on the data led to the recognition of 9 main components for the dataset; the first 5 were components with eigen values greater than 1 and a cumulative percentage more than 85%. Arsenic, antimony, cadmium, lead and zinc in the first component, cobalt in the second component, bismuth in the third component, copper in the fourth component and nickel in the fifth component had the highest values.

Alginate biopolymer, due to possessing a high capacity and affinity for heavy metals, is a suitable material for the removal of metals from polluted waters; however, the weak structural consistency of alginate hydogels limits the practical application of this natural polymer in water purification practices. In this study, sepiolite clay mineral was used as a solidifier of alginate hydrogel to produce hybrid materials with different clay:alginate ratios (1:2, 1:4 and 1:8). Subsequently, the sorption of Pb by the prepared hybrid materials was studied in different Pb concentrations (25 to
2000 mg/L) and temperatures (15, 25, 35 and 45 °C). The results showed that the Langmuir and freundlich equations could significantly describe Pb sorption data on the sorbents. Based on the Langmuir model estimation, alginate showed and sepiolite showed the highest and lowest capacities for Pb sorption, respectively; also, the hybrids were intermediates in this respect. The capacity and affinity of all sorbents were enhanced with increasing the temperature from 15 to 45 °C. Standard enthalpy changes (ΔH°) were found to be positive, confirming that the process of Pb sorption on the sorbents was endothermic. Positive values were also obtained for the standard entropy changes (ΔS°), suggesting increased randomness at the solid-solution interface during the sorption of Pb ions on the sorbents. The values of the standard free energy change (ΔG°) were negative for all different temperatures, thereby indicating that sorption on the sorbents was spontaneous and favorable. Overall, it could be concluded that modification of alginate with sepiolite might cause the decreased sorption capacity of alginate; however, the hybrid materials are good candidates for the Pb removal from aqueous solutions because of their high sorption capacities.

High concentrations of heavy metals in street dust are considered to be a serious risk to the human health and the environment. In this study, 30 dust samples were collected from the pavements in the main streets of Abadan to determine the level of pollution of heavy metals in the street dust. Heavy metal concentrations were analyzed by inductively coupled spectroscopy (ICP-OES) method. The level of heavy metals pollution was estimated based on enrichment factor, pollution index and Nemro Integrated Pollution Index. The average concentrations of heavy metals such as Pb, Zn, Cu, Cr, Cd, Ni, V, As and Co were 59.13, 287.50, 112.97, 50.03, 0.52, 56.77, 35.83, 7.10 and 7.53 mg/kg, respectively. Based on the average enrichment factor (EF), Ni, Cu and Pb had high levels of contamination and Zn contamination was high. According to the mean of pollution index (PI), heavy metals of Zn and Pb had a high contamination. According to the Nemro Integrated Pollution Index (NIPI), 96.66% of the samples had a high degree of contamination. The spatial distribution pattern of the heavy metals concentration showed that in the areas with high population densities, high traffic volumes and urban shopping centers, heavy metal pollution was severe.

Trees decline is a complex physiological disease that results from the interactions between several factors, one of which is heavy metal stress that ultimately leads to the death of trees. This experiment, which was conducted during 2016-2017 at the campus facility of the Department of Horticulture at Isfahan University of Technology, was conducted to investigate the effects of inoculation with arbuscular mycorrhizal fungi (AMF) (Rhizophagus intraradices and Funneliformis mosseae inoculated, and the combination of both species) and plant growth promoting rhizobacteria (PGPR), Pseudomonas Flourescens, on the growth responses of Arizona cypress (Cupressus arizonica G) to different concentrations of cadmium (0, 5, 10, 15, 20); this was done as a factorial experiment based on a completely randomized design, with three replications. The interactions between AMF, PGPR, and cadmium on potassium and iron concentration, height, and dry weight of Arizona cypress seedlings were significant. By increasing the concentration of cadmium in most of the treatments, the colonization, phosphorus, potassium and iron concentrations, height and dry weight of the shoot Arizona cypress seedlings were decreased, while the percentage of electrolyte leakage and proline content were increased. The AMF-inoculated plants increased phosphorus, potassium and iron concentrations, Height, shoot dry weight, proline content and reduced electrolyte leakage percentage, as compared to non-mycorrhizal (control) plants. In plants inoculated with both microorganism (mycorrhizal fungi and Pseudomonas), there was a positive effect regarding the concentration of nutrients such as potassium and iron; there was also the improvement of growth characteristics such as height and dry weight of the seedlings, as well as the appearance and freshness of the plant. The results, therefore, showed that inoculation of Arizona cypress seedlings with the combination of mycorrhizal fungi and Pseudomonas fluorescens bacteria could have a positive effect on the growth and survival of this tree under Cadmium stress condition.

The present study was conducted to evaluate the ecological risk indices of Zn, Cu, Cd, Pb and Ni in the soils from Urmia region (Ghahramanloo village), as irrigated with treated wastewater. Accordingly, six different soil sites (five soil sites under wastewater irrigation and one soil site under well water irrigation as the control) were selected and sampled (AP horizon, 0-30 cm depth). Soil samples were air dried, passed through a 2-mm sieve, and analysed to determine the chemical properties and the studied heavy metals. The results showed that irrigation with the treated wastewater significantly increased the total elements in the order of Cd (228%)> Zn (118.5%)> Ni (81.5%)> Pb (54.2%)> Cu (23.5%). Nevertheless, with the exception of cadmium, other elements were within the admissible range based on the national and international standards. Ecological risk index (min = 125, max = 152, mean = 140) showed a considerable risk in all studied soils and Cd could be regarded as the major metal affecting the index yield.

Heavy metals in street dust, as one of the most important environmental consequences of human activities, have attracted many researchers' attention in recent years due to their toxicity and sustainability. Therefore, this study aimed to investigate the hazard of heavy metals (lead, zinc, copper, chrome, cadmium, nickel, vanadium, arsenic and cobalt) on human health in street dust in Dezful. To this end, 30 dust samples collected from sidewalks of main streets of Dezful were analyzed by Atomic Absorption (AAS). The level of heavy metals pollution was estimated based on the pollution index and Nemro Integrated Pollution Index. Moreover, the spatial pattern of the concentrations of metals in street dust was prepared in GIS. The average concentrations of heavy metals in Pb, Zn, Cu, Cr, Cd, Ni, V, As and Co were 54.2, 223.6, 50.6, 44.4, 0.4, 45.8, 37.8, 3.3 and 7.6 (mg/kg), respectively. The average concentration of all heavy metals except As, V and Co in the samples of dust in the city of Dezful was several times higher than that of the background one. Based on the average EF and PI in the target area, heavy metals of Zn and Pb have high contamination. Based on the evaluation of NIPI, 100% of samples have high degree of contamination. The results showed that the source of pollution of the studied metals such as urban transport and burning of fossil fuels was anthropogenic.

Long- term exposure to street dust because of the potential toxicity of heavy metals can cause harmful effects on the human's health by inhalation, ingestion and dermal contact. In this study, 25 dust samples were collected from the sidewalks of the main streets of Ilam and analyzed by inductively coupled spectroscopy (ICP- OES) method. The mean concentration of the studied metals was: Pb (58.80), Zn (213.24), Cu (63.12), Cr (45.84), Cd (0.37), Ni (43.73) V (30.92) and As (5.00) (mg / kg). Based on the average value of the potential ecological risk (Er), the heavy metals of Pb, Zn, Cu, Cr, Ni and V had a low ecological risk and Cd showed a moderate one. The highest non- carcinogenic risk (HQ) in children and adults was related to As through ingestion and Cr through the dermal contact pathway; on the other hand, the lowest amount was due to the Cd via the inhalation. Cumulative non- carcinogenic hazard (HI) of all heavy metals in the street dust have been found to be higher for children rather than adults. In both age groups, Cr and Pb had the highest and lowest risk of carcinogenicity (RI), respectively. The obtained results, therefore, indicate that the main source of heavy metals in the study area is anthropogenic sources such as traffic, industrial facilities and fossil fuels burning.

Sediments are the sink where various contaminants accumulate; they are an inseparable component of ecosystems; among heavy metals are very important because of their harmful effects on the ecosystems and their long extremely long persistency. The present study was conducted to determine the concentration and contamination degree of heavy metals (Iron, Zinc, Copper, Manganese and Nickel) in the coastal sediments of Bushehr Port. In order to sampling sediments, a distance of 10 km was considered. Acid digestion method was used to prepare the samples for metal analysis. Also, the physical properties of the sediments were measured using the standard methods. The metal enrichment and contamination status in the sediments were determined using the contamination degree (Cd), the modified degree of contamination (mCd), the contamination factor (CF), the enrichment factor (EF), and the geoaccumulation index (Igeo). Based on the results, the distribution of heavy metals in sediments were obtained as Ni Fe> Mn > Zn > Cu >. In the present study, due to the distance between Asalouyeh and Bushehr port, a low nickel concentration was obtained. The results of Igeo and other indices showed that the surface sediments of the study were uncontaminated. Comparison of heavy metals in Bushehr Port sediments with sediment quality standards showed that the concentration of metals in this study was less than the standard levels. As a result, the Coastline of Bushehr port was not contaminatied with iron, zinc, copper, manganese, and nickel metals. The study, therefore, indicated that although there were slight changes in these indices, the combination of the indices could give us a comprehensive cognition of heavy metals risks in the surface sediments of the Bushehr Port.

Shortage of water resources and deterioration of water quality have urged the need to develop new technologies for the removal of contaminants from water. Heavy metals produced by municipal and industrial activities are among the most toxic contaminants present in the natural and waste waters. Different methods have been developed for the elimination of heavy metals from water resources and industrial waste waters. Adsorption is an effective and economic method for the water purification purposes. Nowadays, clays and natural polymers have been widely used as the adsorbents for heavy metals, due to their eco-friendly nature, natural abundance, low cost and high specific surface area. If these adsorbents are used as a hybrid material, some of their physical and chemical restrictions would be alleviated. In this study, polyacrylic acid–bentonite hybrids and natural bentonite were compared in terms of Pb adsorption in the batch and fixed-bed column systems. Besides, the effect of pH on Pb retention was investigated in both systems. The results of the batch studies showed that Langmuir and Freundlich isotherm models were appropriate in ing quilibrium Pb sorption data. Pb sorption by the sorbents was increased with the rise in solution of pH from 4 to 6, showing the greatest Pb sorption capacity at pH values of 4 (83.29 mg g^-1) and 6 (103.3 mg g^-1). Different indices of filtration and adsorption, including average relative effluent concentration, relative adsorption index, relative transmitted index, and filtration coefficient, were calculated from the break-through curves, indicating that the polyacrylic acid-bentonite nanocomposite was superior in the Pb sorbtion, as compared to bentonite. Also, a higher pH value resulted in the greater Pb removal from the solutions.  

Soil pollution by heavy metals is a serious environmental problem that threatens the human health. The present study was carried out to investigate and detect the contamination of heavy metals of arsenic, copper, lead, zinc and iron due to human and natural activities in the sediment of lake bed and the surface soils of the eastern part of Urmia Province, West Azarbaijan Province. A total of 20 soil samples and surface deposition from the depths of 0 to 30 cm were collected randomly from the studied areas. After preparing the samples, extraction was carried out to determine the concentration of the heavy metals in the soil by using hydrochloric acid and nitric acid, and the total concentration of metals was measured using ICP-OES. The results of the calculation of the contamination factor showed that copper, iron, zinc and lead in the class of low and medium pollution and arsenic in 65.5% of the samples were very high in the class. The high concentrations of copper, lead and zinc contamination in the margin of the city and the contamination of arsenic in the lake bed were observed. The analysis of the contamination factor maps and contamination index with land use and geological map showed that copper, lead and zinc were mostly affected by human activities and arsenic influenced by the maternal materials in the region.

Dusts contain heavy metals such as Pb, Zn, Cu, Cr, Cd and As that can threat human's health and environment. Therefore, the spatial distribution of heavy metals concentration and soil pollution monitoring and environmental quality protection seem to be essential. To assess heavy metals pollution level in Ahvaz street dust, 115 street dust samples were collected from main pedestrians. The samples were analyzed by Atomic Absorption (AAS). The pollution level was estimated based on the geo-accumulation index (I_geo), contamination factor (CF) and the enrichment factor (EF). The average concentration values of Pb, Zn, Cu, Cr, Cd and As were found to be 197.6, 150.1, 179.7, 101, 5.6 and 14.2 mg/kg, respectively. Pearson's correlation coefficient also indicated that Pb, Zn, Cu and Cr had a significant correlation showing similar possible anthropogenic sources. On the other hand, Cd and As showed a lower correlation with other metals, indicating that they belonged to the geogenic sources. The results of contamination factor, enrichment factor and geo-accumulation index also indicated that Pb, Zn, Cu and Cd had a high contamination level.  Also, areas with high population density, heavy traffic volume, and industrial activities exhibited a high level of heavy metals contamination.

Drilling material from the tunnel of the Tehran-Shomal highway was estimated to be about 2.5 Million Cubic Meters by the project authorities. Sadly, from the beginning, the drilling materials had been deposited on the open space in the floodplain of the Chaloos river with slightest environmental considerations. During the previous years, weathering and leaching from the drilled materials besides the discharge of drain water from the tunnel had led to seriouse contaminations and the deterioration of the water quality of the Chaloos river. In this paper, the ecological risk of nonorganic pollutants due to drilled materials was investigated. The sampling was done from the excavated materials and river sediment in five different locations throughout a complete year. From the many pollutants, Nickel, Cadmium and Copper were chosen to be investigated. The results showed that almost 15 percent of the samples had a high degree of pollution, while 60 percent of them were clean and the other 25 percent included the highly contaminated ones. All samples were also estimated to have a low to high ecological risk.

Due to the importance of nickel (Ni), and the effect of common soil additives on Ni fractions distribution, the present study was conducted to evaluate the effect of zeolite and vermicompost on nickel fractions over time. The experimental design consisted of a factorial combination of two levels of vermicompost (zero and 2% by weight), three levels of zeolite (zero, 4% by weight of Firoozkooh zeolite, and 4% by weight of Semnan zeolite), and two soil texture (clay and sandy loam) in a completely randomized design in triplicates. Treatments were contaminated with 50 and 100 mg nickel/kg soil. Ni fractions were extracted and measured at 20 and 60 days. The results showed that in initial soils, Car-Ni in sandy loam soil was higher than in clay soil, while the content of Fe, Mn- Ox Ni, OM-Ni, and Res-Ni in the clay soil was higher. In sandy loam soil, more nickel was recovered in Exch- and Car-fractions, while nickel recovery was higher in Mn, Fe-Ox Ni, OM-Ni, and Res-Ni in the clay texture. Zeolite addition caused a significant decrease of Exch- and Car-Ni in the clay soil on 60d and 100 mg/kg Ni level. Exch-Ni was reduced due to vermicompost application. Vermicompost application caused the decrease in Fe, Mn Ox-Ni in both studied soils and times, and OM-Ni increased by vermicompost application. Aging generally reduces the Exch-Ni but changes in Car-Ni over time depending on the soil texture. Aging did not affect Mn, Fe-Ox Ni, and Res-Ni, while OM-Ni increased over time in clay soil.