Water scarcity is one of the greatest global environmental challenges of the 21st century. Use of wastewater for irrigation of agricultural and green lands in arid and semi-arid areas has therefore been received special attention to overcome the water shortage in these areas, which in turn can significantly affect the soil quality characteristics. Soil quality is defined the capacity of the soil to perform its roles in the ecosystem to maintain fertility and biological survival in order to improve the health of plants, animals and humans. Isfahan University of Technology (IUT) has been using treated wastewater to irrigate the green space area of the university for about 10 years. This research was conducted to investigate the effect of wastewater irrigation on some soil quality parameters in green space of IUT. Based on the irrigation history, three sites were selected for soil sampling: site A) alternately irrigated with wastewater and fresh water, site B) irrigated with wastewater during the last 10 years, and site c) alternately irrigated with wastewater and fresh water. The soil sampling was performed from 0-10 and 10-30 cm depths. Control unirrigated soil samples were also taken from each site. Chemical indicators of the soil quality including pH, electrical conductivity, organic matter, total nitrogen, available phosphorus, available potassium, soluble sodium, total heavy metals, and soluble calcium and magnesium ions; soil physical quality indicators including saturated water content, field capacity, wilting point, available water, relative soil air capacity, relative filed capacity, ventilation indices, bulk density, and hydraulic conductivity; and a soil biological quality indicator (basic microbial respiration) were measured in the samples by the standard methods. The obtained results showed that the electrical conductivity, organic carbon, total nitrogen, available phosphorus, available potassium, soluble calcium and magnesium, and microbial respiration were significantly increased in the soils irrigated with wastewater compared to the corresponding control soil samples and those irrigated intermittently with wastewater and fresh water. Moreover, significant increases were detected for the total concentrations of Pb, Zn, Cd, Cr and Cu in wastewater-irrigated soils, with the concentration of the two latter metals being higher than the regulatory guideline levels. On the contrary, soluble sodium concentration and sodium adsorption ratio in the soils irrigated with wastewater were lower than those in the soils irrigated with fresh water and the control. Most of soil physical quality attributes, however, did not show significant changes due to the wastewater irrigation. Overall, the use of wastewater for irrigation in green space of in IUT has been beneficial to most soil quality indices; however, the build-up of some metals and other possible hazardous materials should be considered for further eva‎luation.

عليرضا گوهري

عليرضا گوهري , محمدعلي حاج عباسي جورتاني

عليرضا گوهري , محمدعلي حاج عباسي جورتاني