Department of Agriculture, Yadegar-e-Imam Khomeini (RAH), Shahre Rey Branch, Islamic Azad University Tehran, Tehran, Iran.
Zahedan Branch, Islamic Azad University, Zahedan, Iran.
Environ Geochem Health. 2020 Dec;42(12):4269-4280. doi: 10.1007/s10653-020-00697-x. Epub 2020 Sep 8.
With respect to water crisis, using urban wastewater to irrigate urban green spaces is an upcoming strategy. The pollution of lands irrigated with wastewater is one of the upcoming challenges. The main purpose of the present study was to investigate contamination indices of soils irrigated with wastewater. In this study, field experimental method in statistical form of totally random blocks with three reiterations for considered treatments was employed. To this end, one piece of three-hectare grass irrigated with wastewater and one piece of land irrigated with well water (control sample) were selected out of the green spaces of Zahedan refinery. Then, 30 compound samples were randomly taken from the depth of 0-50 cm of three lands' soil. The refinery wastewater outlet and wall water were also sampled. Physicochemical and biological features of wastewater, wall water and soil samples irrigated with the refinery wastewater and well water were measured according to the standard methods. The obtained data were analyzed using MSTAT-C software. Based on the obtained results, the modified degree of contamination (mCd) of highly and lowly used elements in the considered soils in the experiment was less than 1, indicating a low-contamination status. PLI index of the mentioned elements in the surface soil of grass irrigated with wastewater was higher than 1 and by wall water was less than 1. The concentration of sulfur in surface soil of the two treatments under investigation was in a highly severe enrichment factor (EF ≥ 50). In addition, the concentration of nitrogen, magnesium, zinc and manganese in the surface soil of palm trees and that of manganese, copper and manganese in the surface soil of the grass irrigated with wastewater had a high enrichment factor (5 ≤ EF < 25). Geoaccumulation index (I) of sulfur in the surface soil of the pieces irrigated with wall water (control) and that of potassium in the surface soil of the grass irrigated with wastewater were in no-contamination or average-contamination statuses (0 < I ≤ 1). Other elements were in non-contaminated status (I ≤ 0) in terms of I. The results of investigation of soil contamination indices showed that the soil contamination status of the study area due to wastewater irrigation was low to medium. Therefore, periodic and more accurate monitoring of wastewater treatment plant of Zahedan can be used from this wastewater for landscapes irrigation.
关于水资源危机，利用城市污水灌溉城市绿地是一种即将出现的策略。污水灌溉土地的污染是即将面临的挑战之一。本研究的主要目的是研究污水灌溉土壤的污染指数。在这项研究中，采用了完全随机区组的田间试验方法，重复三次。为此，从扎黑丹炼油厂的绿地中选择了一块灌溉污水的三公顷草地和一块灌溉井水（对照样本）。然后，从三块土地的 0-50cm 深度随机抽取了 30 个复合样本。还对炼油厂废水出口和墙壁水进行了采样。根据标准方法测量了炼油厂废水、墙壁水和灌溉污水和井水的土壤样本的理化和生物特性。使用 MSTAT-C 软件分析所得数据。根据所得结果，实验中考虑土壤中高使用和低使用元素的修正污染度（mCd）小于 1，表明污染程度低。污水灌溉草地表层土壤中所述元素的 PLI 指数高于 1，而墙壁水的 PLI 指数低于 1。两种处理方式下表层土壤中硫的浓度富集因子（EF≥50）较高。此外，调查中两种处理方式下油棕表层土壤中的氮、镁、锌和锰以及污水灌溉草地表层土壤中的锰、铜和锰的浓度均具有高富集因子（5≤EF<25）。灌溉墙壁水的两块土地表层土壤中的硫的地质累积指数（I）（对照）和灌溉污水的草地表层土壤中的钾的地质累积指数处于无污染或平均污染状态（0<I≤1）。其他元素根据 I 处于无污染状态（I≤0）。土壤污染指数的研究结果表明，由于污水灌溉，研究区域的土壤污染状况处于低到中等水平。因此，可以从扎黑丹污水处理厂定期更准确地监测这种污水，以用于景观灌溉。
