Long term effects of different irrigation methods with wastewater on heavy metals accumulation in soil

Demand for water resources in different parts of the world, necessitate the use of wastewater. In using wastewater the soil health must be considered. This study was carried out at Green Space Zob Ahan in the years 1382 to 1385. In this study, the effects of urban and industrial wastewater irrigation on some chemical properties of soil for three years by using five different irrigation treatments were examined. The treatments were as follows: surface irrigation (FI), surface drip irrigation (SDI), subsurface drip irrigation in 30 cm depth (SDI30), Sub surface drip irrigation in 60 cm depth (SDI60) and irrigation procedures babbler (BI). At the end of the experiments, solid samples were taken of the soil of zero to 30, 30 to 60 and 60 to 90 cm depth in order to measure the heavy metal. Lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn) and manganese (Mn) were measured by using atomic absorption in soil samples. Results showed that the density of heavy metals in urban and industrial wastewater is in an allowable range and heavy elements of soil are not limiting factor. And also concentration of heavy metals was higher in the zone of wastewater injection and as whole treatments SDI60 and BI respectively had the highest and least amounts of heavy metals.