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

In this research, the simulation and phase transfer of heavy metal solution in the river has been done by developing a one-dimensional qualitative model. Environmental parameters (T), temperature, dissolved oxygen, (DO) (pH) and salinity (EC) are considered as influencing parameters on the change in the concentration of the solution phase of heavy metals lead, cadmium and zinc in springs and wells of the displacement-diffusion equation. Became to determine the above hydrodynamic and environmental parameters for use in the developed model, Hec-Ras hydrodynamic model and Qual2kw qualitative model have been used. In decoupling the spring and well terms of the displacement-diffusion equation of the qualitative model developed using the measured data from the Sarouk River, various relationships were considered to relate the kinetic coefficient of the first-order reaction of the dissolved phase of heavy metals to the above environmental parameters. And to find the constant coefficients of these relations, the method of minimization of simulation errors and Vba coding was used, and the linear relation including all the above parameters is considered as the final relation. The kinetic coefficient of the reaction is different in different parts of the river, and to simulate and determine the concentration of the solution phase of heavy metals at each point, the kinetic coefficient of the reaction corresponding to the same point should be used. Also, there is a significant increase in the accuracy of the developed model if the above environmental parameters are used in the spring and well term of displacement-diffusion equations and the effect of other qualitative parameters is insignificant, which indicates its proper efficiency in simulating the dissolved phase of heavy metals in the river.

Today, one of the problems with drinking water from groundwater is its quality. Many substances dissolved in water are undesirable. Minerals, gases, and organic matter dissolved in water can cause unpleasant colors, tastes, and odors. Some chemical compounds may be toxic, and some soluble organic components have been shown to be carcinogenic. Of course, it should be noted that not all water-soluble substances are undesirable, but the amount of desirable water-soluble substances is very small. In this study, the water quality of Birjand plain aquifer is measured using an indicator called groundwater pollution index (PIG). This index evaluates the quality of groundwater chemically. The PIG index quantifies the concentration measured in water samples according to the limit in the World Drinking Water Standards (WHO). For this purpose, zoning maps of chemical parameters affecting the PIG index including chlorine, sodium, potassium, calcium, magnesium, TDS, pH, bicarbonate, sulfate were prepared using Arc GIS software (10.3); Then PIG index calculations were performed in GIS software and groundwater pollution index map was drawn.According to the classification, 43.25% of the total aquifer area is low and insignificant pollution, 47.9% of the areas are moderately polluted, 8.22% of the aquifer is highly polluted and 0.63% is highly polluted. This indicates that the pollution of the aquifer of Birjand plain is moderate to chemical elements and failure to observe the optimal use of groundwater can increase pollution in the aquifer.

Investigation of water quality variations in rivers is one of the important criteria for determining the health of watershed. Quantitative and qualitative monitoring plays an important role in sustainable management of river ecosystems. In this regard, the present study was carried out to evaluate the water quality of Ziarat River in Golestan Province, after water sampling from six stations along the river from December 2016 to July 2017 using NSFWQI index. Correlation analysis and cluster analysis were also used to find out the relationships between physical and chemical parameters of water. The results were compared with the standard values of the World Health Organization (WHO) and US Environmental Protection Agency (EPA). The results of this study shows higher values of BOD, Na, Ca and PO4 at the downstream station, as compared to the ones in the upstream stations due to reciving wastewater from different sources. Statistical analysis indicates that there is a significant and strong relationship between some physical and chemical parameters of the river. The results showed that the mean concentration of DO, TDS, Cl, Na, Po4 and NO3 are 5.4, 627.5, 110.02, 48.5 and 9.25 mg/l respectively, and the mean value of Electrical Conductivity was 1028 μs/cm. The comparison of NSFWQI values at the six stations of Ziarat River in different seasons indicated that the first station (Tolboneh, Upstream) had the highest value (55) in May, and the sixth station (Downstream) had the lowest value (35) in July. According to this index, the river water quality is medium in the upstream station and bad in the midstream and downstream stations. The results interpretation showed from upstream toward downstream stations, the pollution load increases and the water quality decreases. Therefore, in order to manage the river water quality, the focus should be done on emission control of point source and nonpoint sourec pollusions. The results of this study provide the opportunity for decision on monitoring and controlling pollutant sources and the proper measures for restoration of river ecosystem for effective use in various applications. Finally, according to the results obtained from NSFWQI index, it can be said that the NSFWQI index describes the quality of water resources easily and reliably and its application is usefull for water resources management of other rivers.

Extraordinary withdrawal of groundwater resources has caused severe damages to aquifers, and the country's plains are facing subsidence due to this situation. In this regard, following the encouragement of the government by offering financial supports, many of farmers have volunteered to run pressurized irrigation systems. Therefore, gathering proper quantitative and qualitative data of water resources is necessary for sustainable agriculture. In this study, water quality of 103 agricultural wells in Sarab plain, which owners are applying for the operation of pressurized irrigation system, was investigated. To determine the water quality conditions of these wells, the magnesium absorption ratio (MAR), permeability index (PI), salinity potential (PS), Kelley's Ratio (KR), sodium absorption ratio (SAR) and soluble sodium percentage (SSP) indices were evaluated along with some other chemical parameters in the studied plain. The EC, SAR, MAR, PS and chloride indices indicated a decline in water quality from east to west and from south to north of plain. Approximately, water in 50% of wells were in the C3S1 class and the average KR of all wells were in a suitable condition with the value of 0.46. Except for one case with the value of 15.52, the remaining wells water had non-alkaline water with the SAR values less than 15. Only 17% of wells water had SSP values over 40% and they were not suitable based on this indicator. Most of the samples were located below the standard limit of 50% for MAR. Finally, in this study condition the application of sprinkler and tape irrigation systemsfor 90% of wells is recommended and for 10% of the rest of wells gated the pipes irrigation system may be adapted.

Water quality river is important from the economic, social and environmental aspects, and its importance is felt in the planning of water resources management and health assessment of watersheds. The present study aimed to investigate the water quality of Qarasoo River in Golestan province by descriptive cross-sectional method using qualitative variables and biological parameters of water in hydrometric stations located on Qarasoo River during the period from 1380 to 1393. An overview of the relationship and sources of physicochemical variables provides. Based on the results of chemical analysis and plotting the Schoeller, Wilcox and Piper diagrams, the water quality of the river is not suitable due to the high concentrations of sulfate, sodium and chlorine ions according to the drug Schoeller diagram, and is agricultural according to the Wilcox In the C3S1 classification, which represents a moderate quality. Also, according to the Piper diagram, which shows the hydrothermal type of water, the qualitative water type is introduced as Calcium-Magnesium-Chloride type. For improving the quality of river water and its efficient, by creating suitable environmental conditions and improving the ecological conditions in the river, point and non-point pollutants entry into the river water especially urban sewage and industrial wastewater and agricultural pollutants should be prevented with long-term plans.

Change in land use and tillage practices has great influence on soil physical and chemical properties. The present study has focused on the effects of converting undisturbed soil to agricultural lands. Chemical and physical soil properties, infiltration, cation exchange capacity (CEC), electrical conductivity, pH, bulk density, porosity, sodium, potassium, total Ca + Mg, organic matter percentage, sodium adsorption ratio (SAR) and lime percentage were measured using standard frequently used methods. Fifty soil samples from agriculture land and other 50 soil samples from undisturbed land were collected from 0 – 30 cm depth and different statistical analysis were performed. Agriculture land is Cultivated for more than 20 years. The results showed that change in land use from undisturbed to disturbed soil did not significantly changed soil organic matter content. Also, soil electrical conductivity showed a huge increase whereas pH showed non-significant changes due to land use change. Unlike pH, SAR, organic matter percentage and lime percentage, some other soil parameters showed significant decrease in quality through land use change. Correlation coefficients of the effective factors were calculated to explain the main reason for lowering soil quality. The results showed that sodium in EC; bulk density in porosity and CEC; sodium and Ca+Mg in SAR; EC in soil infiltration and Ca+Mg in organic matter showed the most correlation.