جستجوی مقالات مرتبط با کلیدواژه « pollution » در نشریات گروه « آب و خاک »

Rivers play a crucial role as a primary water source for societies, emphasizing the need for continuous monitoring of their quality. In this article, we focus on the assessment of water quality in Dinachal River, located in Gilan province. The evaluation was conducted through field studies, sampling, and laboratory methods. Specifically, we measured and analyzed five hydraulic parameters and thirteen water quality parameters, including nitrate, phosphate, temperature, and acidity. The study encompassed seven selected sections along a 25 km stretch of Dinachal River in September 2021. To analyze the data, we employed various methods such as Schoeller, Piper, and Wilcox, along with the FAO and WQI indices. Spatially comparing the river water quality revealed a consistent increase in most parameters from the upstream section, with a steeper rise observed from the station near SafarMahaleh village (section4) towards the river's end. Notably, three parameters electrical conductivity, nitrate, and total dissolved solids experienced significant increases. Electrical conductivity rose from 315.67 µS/cm to 712 µS/cm, total dissolved solids increased from 202.03 to 455.68 mg/l, and nitrate levels elevated from 11.27 mg/l to 69.47 mg/l along the river. Conversely, nitrate levels rose from 19.4 mg/l to 21.4 mg/l, and electrical conductivity increased from 328 µS/cm to 416µS/cm. When comparing data between 1996and2016, specifically for the months of July and June, we noted that agricultural drains had caused nitrates to exceed the permissible limit. The findings indicate an overall deterioration in certain parameters, particularly in relation to electrical conductivity, nitrate levels, and total dissolved solids. These results emphasize the need for effective measures to mitigate pollution sources and preserve the river's water quality for the well-being of the surrounding communities.

Today, groundwater pollution has become a serious environmental problem. On the other hand, climate change affected the quality of aquifers. The results showed that the quality of groundwater resources changed over the time and some cations such as arsenic, chromium and some anions like mercury, fluoride, and nitrate penetrated into the water sources. Research showed that there were various methods to eliminate pollution in groundwater, including traditional and cheap techniques also, chemical precipitation methods, ion exchange, absorption, and membrane filtration. Therefore, in the present study, with analytical and descriptive investigation, some common pollutants in polluted aquifers and various methods to reduce pollutants from water were stated. Also, since nanotechnology guarantees long-term access to safe drinking water, some methods of nanoparticle synthesis and their wide applications in reducing aquifer pollution were investigated. The results of these studies showed that nanomaterials can increase the rate of chemical reaction, compatibility with the environment, and selectivity in reducing pollutants from water.

The main purpose of this article is to investigate the issue of human health due to the continuous consumption of nitrate-contaminated underground water among people of different age groups in the vicinity of Lahijan depot. Therefore, in this study, 34 groundwater samples were collected during the wet (November) and dry (September) seasons, and the main ions were analyzed in the laboratory. Nitrate concentration in the wet season varied from 18 to 30 mg/L with an average of 24.2 mg/L and in the dry season from 8 to 24 mg/L with an average of 14.5 mg/L. The amount of NPI nitrogen pollution index showed that in the wet season, 23% of the samples are healthy and 77% of the sample locations have low pollution, and in the dry season, 82% of the samples are healthy and 18% of the samples have low pollution. The noncarcinogenic risk assessment model showed that health issues are among different age groups, including infants, children, youth, adults, and the elderly. The results of the carcinogenic risk showed that in the wet season, 65% of the underground water samples and in the dry season, 18% of the samples are unsuitable for drinking by the age group of 6 to 12 months. Identified sources of nitrates include nitrate sources found in the study area, anthropogenic activities such as Lahijan landfill and village residents' waste. Therefore, periodic water inspection, health check-up and common treatment plant in rural areas are corrective measures that should be taken to reduce the severe effects of nitrate-contaminated drinking water in the study area.

The relationship between the concentration of heavy metals and physicochemical factors was studied in the fine-grained sediments of the tidal section of the Mehran delta where mangrove trees have grown. Surface sediments of the tidal zone of the Mehran delta were sampled. The grain size distribution, calcium carbonate, organic matter contents, pH/Eh, and heavy metals concentration were determined in the mud fraction of the sediments. The presence of high calcium carbonate in sediments is an effective factor in the abundance of Mn, Cd, and Pb. Clay and organic matter as adsorptive have contributed to the high concentration of Zn, Cu, while Fe oxy-hydroxides have affected the concentration of Co, Cr, and Ni. According to the index of Enrichment Factor (EF), the average enrichment of the elements in the studied sediments from high to low order is Cr, Ni, Cd, Zn, Mn, Pb, Co, and Cu. According to the Pollution Load Index (PLI), none of the delta sediments including sediments from inside and outside of the mangrove forestare classified as polluted to the heavy metals. According to the Igeo Index, most samples, and only Cd, Cr, and Ni show slight pollution in some samples. Accordingly, there is no current threat of contamination of potentially toxic elements of natural and anthropogenic origins to the mangrove environment and Mehran delta.

The rapid growth of the world's population in recent decades has led to growing problems in terms of water supply and agricultural resources, and limited water resources are one of the major problems in the agricultural sector. The treated urban and industrial wastewater, which its pollution load is reduced by adding amendments, can be a suitable way to provide plant water and nutritional requirements. Thus, this research aimed to investigate the effect of different amendments on soil properties irrigated with wastewater from Bu-Ali industrial region in the Hamadan province.

For this study, treated wastewater was collected from Bu-Ali Industrial town, Hamadan Province. The greenhouse experiment in the Bu Ali Sina University was conducted in a completely randomized design with three replicates with loamy soil irrigated with wastewater. In this research, nine treatments including citric acid, compost, manure, gypsum, composite treatments (gypsum+ manure, gypsum+ compost, citric acid+ manure, citric acid+ compost), and control (27 sample) were used to investigate the effect of these amendments on some chemical properties. Soil properties were measured before and after the application of treatments. These properties included pH, electrical conductivity, cation exchange capacity, organic matter, total phosphorus, and available phosphorus and heavy metal concentrations such as lead, nickel, cadmium, and micronutrient such as zinc, copper, iron, and manganese were also measured.

The results showed that the applied wastewater was considered to be unsuitable water with large quantities of sodium. The application of various amendments such as compost, manure, and citric acid in soil irrigated with wastewater can significantly reduce soil salinity (from 2.53 in the control treatment until 2.16 in the compost treatment). The effect of amendments on some chemical properties revealed that the addition of different amendments to the soil irrigated with wastewater resulted in significant changes in pH, electrical conductivity, cation exchange capacity, organic matter, carbonate equivalent calcium, Ca, Mg, and Na cations, total phosphorus, and Olsen phosphorus. The lowest total copper content was observed in the control treatment with an average of 13.84 mg kg-1, whereas the highest content of this element was seen in the treatment of 50% gypsum + 50% compost with an average of 14.93 mg kg-1.

Furthermore, the total and available concentration of heavy metals (Pb, Ni and Cd) in soil treated by amendments was mostly higher than the control soil. However, their values were lower than those in the soil and therefore, it had no adverse effect on the soil in this respect. There is also no problem with other soil characteristics such as salinity. In general, the results demonstrated that the use of these amendments can be a useful way to reduce pollution levels and the absorption of heavy metals in the plant.

Considering the plant's positive response to nitrogen, farmers consume nitrogen fertilizers as much as possible. Excessive consumption of nitrogen fertilizers imposes additional costs on farmers, environmental pollution and direct negative impact on human health. Therefore, it is important to determine the amount of nitrogen-nitrate in the soil, plant and irrigation water in order to use nitrogen fertilizers optimally. In addition, according to the nitrogen balance, the amount of nitrogen deficiency is calculated and given to the plant, therefore the overuse of fertilizer is avoided. Most of the usual methods for nitrate measurement are time-consuming and expensive, spectroscopic measurement (spectrophotometer) makes it possible to determine the amount of nitrogen-nitrate in each of the soil, water and plant in the shortest time, inexpensively and accurately. In this research, we introduced a quick method of measuring the amount of nitrate in each of the water, soil and plant. The results are presented in terms of practical units in the field and soil for farmers and students, including kilograms of nitrogen per ton of product and the amount of nitrogen given through irrigation or nitrogen available in the soil in kilograms per hectare.

The aim of this study is to investigate water pollution in the reservoirs of seasonal river dams and to provide management suggestions to reduce pollutions. In order to establish future management strategies, we examined the quality control of water parameters in seasonal rivers. Ghadruni dam basin is one of the sources of supplying the drinking water of two cities and has a special geographical position. With the increase in the population of the region due to its industrial nature, pollution can enter the reservoir in the near future. Due to using large amounts of chemical fertilizers in the lands around the seasonal rivers, we expect that runoffs from agricultural lands, which flow into seasonal watercourses, affect the quality of their water more than permanent rivers. Rural residential areas are located near these two rivers (Hotkan and Ghadruni). For this purpose, sampling of 6 stations on the dam feeding streams and the reservoir itself has been done. We measured the biological and chemical properties of the water; because they may change due to the entry of agricultural runoff. We measured chemical and biological parameters such as dissolved solids, Temperature, EC, PH, Turbidity, chloride, sulfate, nitrite, nitrate, ammonium, DO, COD, and nitrogen for one year, The obtained results were evaluated and analyzed. The results of studies show that the most important reasons for pollution in the Ghadruni dam basin is the impact of agricultural effluents and domestic and industrial sewage left in the system. Parameters such as EC - dissolved solids, nitrite, nitrate, sulfate, and chloride at the sampling stations had relatively high values. Also, PH values and water temperature were highly different, The problem of pollution in the dam, which is fed by the Ghadrun and Hotkan rivers, can be solved by collaboration between the respected organizations and water resources management plan in this basin.

Since water and soil are important components of the ecosystem ‎and their quality reduction affects the environment and agriculture, it is necessary to determine ‎the effects of pesticides on soil and water resources and determine their residual concentration ‎levels in the land. Agriculture, especially paddy fields, should be controlled and managed. ‎Therefore, the purpose of this study is to determine and evaluate the level of residual ‎concentrations of organophosphate pesticides in soil and water samples of Rudbar County and to ‎investigate their ecotoxicological status.‎

In this study, the multiplicity of 12 stations was determined using a ‎systematic random method in the paddy lands of Rudbar County. In total, 24 samples including ‎‎12 water samples and 12 soil samples were collected. Water sampling was performed in 1-liter ‎dark-colored bottles and soil sampling was performed from the surface layer according to the ‎standard method. All samples were transferred to a laboratory in a freezer containing dry ice. ‎Organophosphate pesticides were measured using the EPA 8041b standard method. All analyzes ‎were performed by gas chromatography with the mass detector in Aria Shimi Sharif Company. To ‎study the ecotoxicological status of pesticides, two databases named National Pesticide ‎Information Center and Pesticide Properties Database were used. The two databases are affiliated ‎with Oregon State University, the US Environmental Protection Agency, and the University of ‎Hertfordshire. Statistical analysis of the data included analysis of variance using one-way ‎ANOVA test, comparison of means using Duncan's test, correlation using Pearson's method, and ‎analysis of principal components using the covariance method.‎

Based on the results, 11 organophosphate pesticides were identified in water and soil ‎samples of Rudbar paddy fields. Ethion in soil and Diazinon in the water had the highest residual ‎concentrations. Sheikh Ali Tues 1 and 2 and Mirzagolband 1 stations with the values of 4.55, ‎‎3.99 and 3.49 ug/kg had the highest amount of Ethion toxin residues in the soil. In addition, ‎Sheikh Ali Tues 2, Mirzagolband 1, and Halimeh-Jan stations with 3.96, 1.71, and 1.68 ug/L, ‎respectively, had the highest amount of Diazinon pesticide in water samples. The results showed ‎that the downstream lands in the area of Imamzadeh-Hashem compared to the upstream lands in ‎Rudbar city have a higher concentration and load of pollution. The mean concentration remaining ‎in soil samples (0.987 ug/kg) was higher than in water samples (0.304 ug/L). Based on the results ‎of pesticides Diazinon, Methyl Parathion, Azinphos Methyl, Malathion, and Ethion in the studied ‎stations showed a significant difference. A comparison of the mean residual concentrations of ‎pesticides with their physicochemical and ecotoxicological properties showed that in terms of ‎potential risk and toxicity for aquatic organisms, the concentrations of BetaMevinephos, ‎Malathion, and Azinphos Methyl pesticides were 0.043, 0.573, and 0.272 ug/kg, respectively. Has ‎been very high, which has put these pesticides in a situation of high and toxic danger to aquatic ‎organisms in the region.‎

Extreme use of pesticides on agricultural land has caused environmental problems. ‎As a result, monitoring and evaluation of pesticide residues in paddy fields are very important ‎because contaminated effluents are discharged directly from rice fields into rivers, depending on ‎several factors. Due to the high levels of residual concentrations of some organophosphate ‎pesticides in the region, it is necessary to hold training courses on farmers' familiarity with the ‎dangers of pesticides to prevent, control, and reduce pollution under the supervision of experts. ‎Also, to fight non-chemically against pests, it is suggested to use the Trichogramma bee in the ‎form of Trichocart to fight the rice stem-eating worm, colored traps, and attractants in paddy ‎fields.‎

The entry of pollutants from agricultural land into water bodies is one of the most environmental issues connected to the tile drainage systems. Also leaching of drain water may cause the required nutrients for crop growth becomes out of reach. Thus, applying Best Management practies (BMPs) to relief the side effects of agricultural tile drainage systems is crucial. Over the past few decades, several BMPs have been introduced and studied with the aim of manage and control the volume and pollutants amount of tile drain water in agricultural lands, of which Controlled Tile Drainage (CTD) is one of them. Due to difficulty and costly nature of long-term monitoring programs, which is often used to assess impacts of applying BMPs on non-point source pollution, the AnnAGNPS model developed by USDA is a reliable alternative to simulate an effect of applying CTD at the watershed scale. AnnAGNPS, a comprehensive computational model that evolved from AGNPS, was designed for evaluating non-point pollutant loadings in agricultural watersheds and river basins. Briefly, AnnAGNPS is a distributed parameter simulation model that subdivides a watershed into small, homogeneous subwatersheds called “cells.” Cells are interconnected by stream channels called “reaches” In this study, an impact assessment of applying CTD on Total Suspended Sediment (TSS), Total Nitrogen (N total), Dissolved Nitrogen (N dissolved) and Surface Runoff were evaluated by AnnAGNPS at the Qharesu Watershed.

Qharesu watershed with an area of about 1670 square kilometers is one of the watersheds of Golestan province, which is surrounded by the Gorganrud watershed area from the north and east, Nekarud watershed in the south and the Gorgan Bay from the west. Finally, it is discharged into this bay. An average meteorological data of 5 statistical years of 2016 to 2020, used as a model input data in order to further adapt to the climatic conditions of the region in future, when tile drainage system is operated. The surface runoff data and suspended sediment load were also obtained from the Siah-Ab hydrometric station (outlet point of Qharesu watershed). Calibration and validation of the model performed by runoff and TSS observation data, in which the degree of confirmity between observation data and model output data performed by using three indices of Nash-Sutcliffe, RSR, and PBIAS.Two tile drain depth scenarios were examined in detail to mimic tile drainage control: The depth of 0.2m (CTD0.2) as an extensive controlled drainage and the depth of 0.6m (CTD0.6) as the recommended depth in the growing season for controlled drainage. The depth of the drainage base considered 1.1m as a reference condition as well.

The results showed that the model is reliable for simulating the studied parameters. The indices of E, RSR and PBIAS for runoff were 0.85, 0.48 and -2.6 for the calibration period and 0.76, 0.44 and -10.9 for the validation period respectively. These numbers were 0.73, 0.43 and -31.7 (calibration) and 0.66, 0.54 and -29.1 (validation) for sediment data.The AnnAGNPS model predicted a slight decrease in runoff and total nitrogen and a moderate decrease in dissolved nitrogen at the outlet of the Qharaesu River under the CTD0.6 scenario (during the growing season). Also, the increase in sediment load due to CTD0.6 was almost negligible. Based on the model results, Controlled drainage to a depth of approximately 0.6m below ground level is a suitable equilibrium point for reducing nitrogen and sediment loads at the watershed scale. Considering the importance of the outlet point of Gharesu, which is discharged to Gorgan bay, and since a significant part of tile drainage system in this watershed has not been impelemented yet, applying controlled tile drainage system is possible at a lower cost and more comfortable. Therefore, the possibility of applying CTD0.6 scenario should be on the agenda of authorities.

This study was conducted to investigate the effects of vegetation type (Alfalfa and Wheat) and slope (5% and 20%) on runoff and drainage pollution in clay loam soil. Sampled soils were repacked in the box with one soil drainage outlet and one surface flow outlet and were cultivated by wheat or alfalfa. A solution containing 0.05 M KCl was poured quickly and uniformly, over the surface of each box, after plant growth. Simulated rainfall was applied to the soil box with the intensity of a constant rate of 64 mm h-1 for 2 hours immediately. Then the concentration of Cl- and K+ were measured in the collected samples of runoff and the drainage outlet. Results showed that the measured concentration of K+ was lower than the Cl- concentration as a result of its absorbable property. The breakthrough curves (BTCs) of Cl- and K+ showed that slope and vegetation type affected the transport of Cl- and K+. The peak of the BTCs for Cl- and K+ in runoff ranked in the order of wheat and 20% slope> alfalfa and 20% slope> wheat and 5% slope> alfalfa and 5% slope, and in the drainage changed to alfalfa and 5% slope> wheat and 5% slope> alfalfa and 20% slope> wheat and 20% slope. For each slope, the intensive vegetation cover of alfalfa than wheat considerably reduces Cl- or K+ pollution in runoff; whereas drainage development of larger and deeper root systems was the cause of higher leached concentrations for both tracers. Based on our research changes in soil surface vegetation cover from wheat to alfalfa are suggested in slope land to prevent surface water pollution; although other factors such as the climate, soil texture, and structure should also be considered.

Chromium is one of the heavy and toxic metals for microorganisms, animals, and plants, which the use of the sources that contain them may lead to serious environmental pollutants. High concentrations of chromium are considered a stress factor for plants that can affect plants' physiological and biochemical properties as a growth-limiting factor. Due to an active chromite mine in the Forumad area of ​​Mayamey city, Semnan province, this research is to determine the status of chromium contamination in water resources, the soil of the region, and plant samples. Regarding the mentioned issue and for the identification, simultaneously sampling of all water resources in the region, including wells, springs, and aqueducts, are implemented. Besides the qualitative analysis and determination of ions (anions and cations), the total chromium concentration is investigated in the Soil and Water Research Institute. The results indicate pollution centers in the areas of Forumad, Pole Abrisham, Estarband, Kalateh-ye Sadat. A sampling of crops, horticulture, and medicinal plants in the region showed that the amount of chromium adsorption in pepper as a national index product of the region was less than the allowable limitation (less than 1 mg/kg), and the initial concerns were largely resolved. The absorption of total chromium in pistachio and pear crops is also within the allowable range, considered in the region's cultivation program. Since the absorption of chromium in sesame seeds, wheat, alfalfa, figs, and some crops is higher than the allowable level, incentive policies should be implemented to improve the cultivation pattern and replace it with contaminated crops. Contamination of soil sources in the region with chromium was investigated at 32 points. The results showed that almost all soil samples are more contaminated with chromium (range 386-142 mg/kg). The results showed that the concentration of total chromium in the four samples sent from Forumad and the Pole Abrisham before treatment was 123.5, 107.2, 127, and 110.6 μg / l after treatment of zero, 6.7, zero, and 4.2 μg / l, which indicates the use of reverse osmosis in drinking water.

Dust is one of the most important environmental pollutants, containing particulate matter and heavy metals. The aims of this study were to determine the pollution level and to identify the distribution pattern of heavy metals in dust samples collected around the Hoveyzeh - Khorramshahr dust center. Thirty points from different urban and rural areas were taken using marble sediment traps to examine the heavy metals contents of the dust particles. The results showed that the concentrations of heavy metals in dust particles follows the order Mn > Zn >Cr > Ni > Pb > Cu > Co. Also, the highest values of enrichment factor were found in the southern parts of the study area, where the oil fields activities are predominant. The lowest concentrations of heavy metals were also observed in rural areas. In most of the stations, both values of enrichment factor and geo-accumulation index were higher in dust samples compared to those of soil samples. The values of geo- accumulation index for Hg, Pb, and Mn elements in dust particles and soil samples were in the range of medium to high pollution (2 ≥ I geo ˂ 3), indicating the impact of various human resources on distribution of these elements. The result of cluster analysis is fully consistent with the results of Principal Component Analysis (PCA), indicating several sources deriving from human activities including oil, industrial and traffic on heavy metals distribution in dust samples.

The river is one of the most important water sources for drinking and agriculture. Therefore, evaluating and modeling the water quality of rivers and examining its qualitative effects on human life, living things, and the environment is undeniable. In this study, the water quality of the Beheshtabad River was simulated using the QUAL2Kw simulation model. The water quality of this river in its two tributaries was analyzed by designing two scenarios to improve it downstream. The simulated qualitative parameters (temperature, Ec, TS, DO, BOD, COD, pH, nitrate, orthophosphate, ammonium, and fecal coliform) were simulated in two scenarios with different flow rates. The results show that by preventing the discharge of water from the upstream rivers (Kiar and Juneqan) due to high pollution and also the addition of water from Bagh-e-Rostam spring along the route, the water quality of this river will improve downstream. Including BOD concentration will improve from 7.32 to 4.23 mg /L, COD parameter concentration will improve from 19.30 to 12 mg/L, DO parameter concentration from 4.9 to 5.9 mg/L, and fecal coliform parameter concentration from 1500 to MPN/100 mL160.

Sediments are the most important sources in the study of aquatic ecosystems. Bottom marine sediments are sensitive indicators for monitoring pollutants as they act as a sink and a carrier for contaminations in aquatic environment. The objective of this research was to evaluate the degree of heavy metal contamination in Kalan Malayer dam and the extent of sediment quality according to three indices. In this study, heavy metals such as As, Cd, Cu, Cr, Mn, Hg, Ni and Zn in 12 station were measured of lake bed sediments. Then, sediment quality was analyzed by calculating of geo-accumulation index, pollution index and enrichment factor. The highest amount of pollution index respectively belonged to As (2.520), Ni (1.225) and Hg (1.138). The results obtained from pollution index, geo-accumulation index and enrichment factor indicated that the As, Ni and Hg were high in 9 to 12 stations. Multivariate principal component analysis (PCA) was performed on the indices data, and two components were extracted which explain 85% of the total variance, and the eigenvalues >1. All heavy metals (except Mn) had positive coefficients with each other. The stations 9 to 12 were located near agricultural farms and the high concentration of some heavy metals in these stations can be due to human and natural resources such as excessive use of agricultural field, the intensive use of pesticides and the entrance of chemical fertilizers aquifers.

Microplastics are plastic particles smaller than 5 mm that are known as emerging contaminants. Most research about microplastics has been performed in aquatic ecosystems and there is limited information about the effects of these particles on soil biological and enzymatic properties. Therefore, the aim of this research was to evaluate the effect of Microplastic particles on some soil properties included basal and cumulative respiration, microbial biomass carbon as well as soil acid and alkaline phosphatase activity. For this purpose, Low-density polyethylene (LDPE) microplastic particles (diameter 0.5 - 1 mm) added to the soil (1, 2 and 4 % w/w). Incubation times for investigation of soil properties and enzymes activity were 87 and 45 days, respectively. The results showed that the microplastic particles increased the soil basal and cumulative respiration rate. Soil microbial biomass carbon increased during the 3th to 17th days of incubation, but decreased after that when compared to control treatment. LDPE Microplastic particles had a negative effect on the activity of acid and alkaline phosphatase and decreased them. The highest decline was related to the microplastic level of 4%. The rate of decrease in acid phosphatase activity was more than alkaline phosphatase activity. Briefly, the results of the present study showed that the microplastic particles can increase soil respiration, but it has a negative effect on phosphatase activity.

In drip irrigation systems, the low surface reactivity of the sand filter for physical-chemical treatment led to the use of other filter media that increase the retention capacity of wastewater contaminants along with the sand. The purpose of this study was firstly to compare the application of sand and geotextile with zeolite in filters to reduce nitrate pollution in wastewater and secondly to compare the quality parameters of Shahrekord University effluent with international standards.

This research was conducted at Shahrekord University in 2014-2015. The wastewater used in this project was prepared from an observation well located near the east door of Shahrekord University. In order to investigate the nitrate status, a factorial experiment was performed in a completely randomized design with three replications. Treatments include control treatment Ctrl (sand without application of zeolite), geotextile without application of zeolite J, sand-geotextile without application of zeolite SJ, sand with zeolite SZ, geotextile with zeolite JZ, and geotextile sand with zeolite. The treatments were poured into cylindrical columns made of PVC tubes. Inlet effluent nitrate and wastewater were measured with a spectrophotometer. The total suspended solid, EC, pH, sodium, calcium and magnesium in the effluent were determined and compared with the standards. Statistical analysis was performed using SAS software.

The results showed that the filters had a significant effect on the effluent nitrate passed from the columns (P<0.01). JZ, SJZ, and SZ treatments showed the highest nitrate reduction with 57, 55, and 52%, respectively. Sand treatment did not affect nitrate as expected. Measurements showed that the amount of nitrate in Shahrekord University effluent for irrigation was less than the allowable amount of some organizations, but was not suitable for irrigation according to the FAO standard. Also, the amount of EC (1.02 dS/m) and suspended solid (109.6 mg/L) was too much for irrigation according to most standards, but the pH and SAR of the effluent were sufficient to be used for irrigation. The minimum and maximum pH values were 7.2 and 8.03, respectively, which were lower than the maximum value of all standards. The measured SAR of the effluent entering the filters was 2.14, which was allowed according to the standards in terms of application in irrigation.

This study showed that sand filters alone did not affect the amount of suspended load in the effluent, but using geotextiles and zeolite in sand filters can reduce nitrate pollution from effluent. The amount of sodium, and total calcium and magnesium in the effluent was higher than the allowable amount for use in irrigation according to the standards of the US Environmental Protection Agency. But the amount of sodium absorption ratio was less than the allowable amount for use in irrigation according to all standards.

Zn-Pb mine tailings of Zanjan (province of Iran) contain high concentrations of toxic metals, especially arsenic that can potentially release into the surrounding soils and water pathways. These tailings create leachate due to their connection with water, which is very dangerous to the environment and to the masses of animals and human beings. Unfortunately the geochemical and mineralogical processes that control arsenic release from tailings are not fully studded. Therefore this research aimed to assess the leaching characteristics of arsenic under different environmental conditions to recognize the parameters and factors controlling its concentration in the leachate.

Leaching of arsenic from Zn-Pb mine tailing was investigated in various environmental scenarios. In order to determine the amount of leached arsenic in different conditions, four leaching protocols, including toxicity leaching procedure test (TCLP), synthetic precipitation leaching procedure test (SPLP), field leach test (FLT) and leachate extraction procedure (LEP) were used. Also, to study the effect of various factors such as pH, contact time, particle size and solid to liquid ratio on leaching of arsenic from Zn-Pb mine tailings batch leaching experiments were carried out. Risk assessment code (RAC) based on fractionation method was also applied to evaluate the environmental risk of arsenic mobility.

The results indicated that in both samples of tailings ,the highest amount of arsenic was measured in the residual fraction that is relatively stable under natural environmental situations. According to RAC index, the tailings in term of arsenic placed in the low-risk tailings group. In TCLP, LEP, FLT and LEP test the concentrations of leached arsenic were low and the highest leaching concentration of arsenic occurred in the LEP test and sample S1. According to SPLP analysis, Zn-Pb tailings will have a high potential for contamination of surface and underground water. The mobility of arsenic in the tailings was entirely influenced by pH, contact time, particle size and solid to liquid ratio. The leaching of arsenic enhanced in acidic and alkaline condition and the amount of arsenic leached in acidic condition was much higher than that leached in alkaline condition. In fact, pH-dependent leaching behavior of arsenic from Zn-Pb mine tailing was amphoteric. Actually pH-dependent leaching behavior of arsenic from Zn-Pb mine tailings was amphoteric. In sample S1, the highest amount of arsenic was released from particles with the size of 500-600 µm, while in the sample S2 particles with the size of 150-250µm released the highest amount of arsenic.

By considering the results of leaching protocols, and arsenic fractionation and also with regards to factors affecting the concentration of arsenic in leaching water, reducing the pore water and contact time, and controlling the pH and preventing the spreading of tailings in the environment are the most important factors in preventing and managing the spread of pollution in the environment.

Nowadays, due to the reduction of water resources, the use of unconventional water sources such as wastewater has been given special attention in the world. The presence of some heavy metals in wastewater particularly in industrial wastewater limits the application. This study was carried out in order to investigate the efficiency of some organic and nano oxide adsorbents in the removal of zinc (Zn) and cadmium (Cd) from industrial wastewater.

The study was done at four steps including the effects of 1), adsorbent mass, 2) exposure time, 3) concentration of heavy metals, and 4) pH on the removal of Zn and Cd from wastewater. At first, an artificial wastewater was created based on 40 mg l-1 Zn and 25 mg l-1 Cd. Four adsorbents including wheat straw and palm fiber as organic adsorbents and titanium nano oxide and iron nano oxide as nano adsorbents each at five doses (0.2, 0.5, 1, 1.5 and 2 g l-1) were applied. Different time durations were implemented in order to assess time effect in addition to the equilibrium time. In addition, the influence of pH in a range of 3 to 6 on the efficiency of adsorbents was examined. Moreover, in order to study the effect of different concentrations of Zn and Cd on the efficiency of adsorbents, three levels of pollution concentrations were generated by the combinations of 40, 80 and 120 mg l-1 Zn and 25, 50 and 75 mg l-1 Cd.

The result showed that the adsorption of heavy metals increased with increasing the dose of each adsorbent in the wastewater. As the application rate of palm fiber, wheat straw, titanium nano oxide and iron nano oxide increased from 0.2 to 2 g l-1, the adsorption of Zn increased by 49.4%, 17.1%, 13.1% and 11.4 %, and the adsorption of Cd increased by 41.1%, 3.8%, 18.0% and 1.5%, respectively. Overall, palm fiber with the optimal level of 1.5 g l-1 exhibited the best efficiency in the removal of Zn (87.2%) and Cd (46.2%). The equilibrium time for the adsorption of both Zn and Cd using wheat straw, palm fiber, titanium nano oxide and iron nano oxide was 300, 120, 30 and 30 minutes, respectively. In fact, the nano adsorbents reached the equilibrium conditions faster than the organic adsorbents. The applied organic adsorbents at pH of 6 and the nano oxide adsorbents at pH 4 had the highest efficiency in Zn adsorption. In the case of Cd adsorption, wheat straw at pH 5, date fibers at pH values of 6 and 3, iron nano oxide at pH values of 4 and 5, and titanium nano oxide at pH values of 4 and 3 showed the highest efficiency. The organic adsorbents at lower levels of pollution and the nano adsorbents at higher levels of pollution found to be more effective to remove the heavy metals from the wastewater.

The findings of this study revealed that during the removal process of Zn and Cd from wastewater, the organic adsorbents had higher adsorption, whereas the nano adsorbents reached the equilibrium conditions sooner.

Mine tailings dams, as one of the important and unavoidable parts of any mine, are considered as a sources of environmental pollution in the areas adjacent to each mine, which has received less attention from an environmental point of view. The present study was conducted to investigate the environmental effects of the tailings dam of Chahar Gonbad copper mine on changes in quantities of some soil pollutants adjacent to the tailings dam of this mine. In this study, according to the location of the region, six samples of sediment from the tailing dam and nine samples of topsoil were collected and the amounts of Pb, Sb, Zn, Cd, As and Cu; as well as soil pollution indices of each element (enrichment factor (EF), Geo-accumulation factor (Igeo), and contamination factor (CF)) were measured and compared with the environmental protection standard. The results of pollutants in sediments showed significant enrichment of Cu and Sb elements in tailings dam sediment samples. Based on the standard values ​​of soil pollution, with the exception of high levels of Cu (38-135 mg kg-1) and As (7.2-17.8 mg kg-1) in some samples, the observed levels of Pb, Zn, Cd and Sb in all soil samples were lower than the environmental protection standards. According to the results of soil pollution indices, the two elements Sb and As had higher EF and Igeo than the other elements, which shows the effect of anthropogenic factors (tailings dam) on amounts of these elements. The results of this study showed, despite the high amounts of Cu in the soil surface samples (due to the nature of the Cu vein deposit in the region), the area adjacent to the dam is not contaminated with other pollutants, although EF of As (4-15.3) and Sb (3-5.9) can be a serious alarm to pollute the area with these elements in the coming years. Based on the obtained results, it is suggested that changes in the pollution of tailings dams as one of the sources of environmental pollution in the areas adjacent to the mines, be continuously assessed and appropriate management measures be applied.