JWSS - Journal of Water and Soil Science

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.