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

In order to investigate the effect of using treated wastewater in agriculture on the chemical quality of groundwater at the northern region of Isfahan, an area of 6000 hectares was studied during the years 2018 and 2019 by sampling 46 wells. The location of the studied wells was in two areas under long-term irrigation with effluent for at least 10 years and the control area. Chemical parameters of the samples such as electrical conductivity (EC), chemical reaction (pH), anions including bicarbonate, sulfate, chloride, nitrate and cations including calcium, magnesium and sodium were measured. The results showed that the effect of using treated wastewater on groundwater quality of the region, in shallow and deep wells has a different behavior. Due to the long-term use of treated wastewater for irrigation of agricultural lands, none of the chemical parameters of the deep wells were significant in compared to the control area. But, in area with shallow groundwater, the chemical parameters of EC, bicarbonate (HCO3) and chlorine (Cl) were significant at 5% level as compared to the control. Most of the wells in this area are deep and only 8% of the wells are shallow. Therefore, according to the results, the use of treated wastewater for agriculture in this region has a negligible effect on the chemical quality of deep groundwater and therefore is recommended for use in agriculture.

This research investigates the factors affecting the quality and nitrate pollution of groundwater of Zeidoun plain in Khuzestan province. To this purpose, 25 agricultural wells were sampled and then the chemical parameters of water samples (including total dissolved solids, temperature, and cations and major anions) were measured. To investigate the factors influencing groundwater quality, compositiondiagrams, mineral saturation index and factor analysis method have been used.The results of this study showed that the groundwater has an unsuitable quality in the vast part of the study area. So that the salinity of groundwater is more than 3000 µmohs/cm in the middle and northern parts of the plain. Also, the concentration of sodium and chloride ions in these areas is more than 400 and 550 mg/l respectively. From the Nitrate pollution view point, groundwater contamination and pollution was occurred in central and northern parts of the study area. The concentration of nitrate in these regions varies from 15 to 100 mg/l. According to the results, the most important factors influencing the groundwater quality are water- rock interaction and pollution by agricultural activities and municipal wastes.

Necessity to use envelope (filter) in subsurface drainage systems is one of the important aspect that should be taken into consideration of the beginning of a drainage project. The first indicator of the need for a drain envelope is the percentage of clay in the soil. In this research، permeameter test was used to determine gradient ratio and evaluate the clogging potential and probability of soil particle passage through the drain plate openings in three clay and clay loam soils with 20-40 percent clay SAR 17 – 83، and EC 10 – 100dS/m. Treatments in this experiment were drainage systems with and w/o envelopes. In envelope d system two types of envelopes (granular and fiber) were used. Outflow variation، system permeability، gradient ratio and exit gradient were investigated. The results. showed that the gradient ratio in the system without envelope were greater than one implying a high clogging potential. Nonetheless، soil downfall was occurred when this index was bexceeded. The ratio of outflow from the systems with granular and fiber envelopes to systems w/o envelopes ranged 2. 0-3. 5 and 1. 4-1. 8، respectively. As hydraulic gradient was increased، system hydraulic conductivity decreased with the greater decrease occurring in the system w/o envelope. Resistance against pressure head was also studied with determining hydraulic gradient failure compared to exit gradient value at each gradient head. Results indicated that the without envelope system in soil no 2 and 3 had، receptively the minimum and maximum performance.