Effect of wastewater on transfer heavy metals and chemical compounds in soil column under basil

Although using of wastewater in agriculture have advantages, but these waters may be contain pathogenic microorganisms, heavy metals or other harmful organic and inorganic compounds. Therefore this elements can be undesirable environmental impacts such as pollution water sources (especially groundwater), soil and plants. Therefore efforts for obtain proper disposal of wastewater in the environment is essential. Therefore the purpose of this study is investigate the effect of wastewater on transfer of heavy metals and chemical compounds in soil column under basil cultivation
This study was conducted based on a completely randomized designed with three treatment watering and triplicates under lysimeter condition. The applied treatments consisted of watering included raw wastewater (W1), treated wastewater (W2) and a composition of 50% raw wastewater and 50% fresh water (W3). For this purpose, 9 cubic (30 cm × 30 cm × 126 cm) metal lysimeters containing a three-layer soil were used. The soil texture from top to bottom of lysimeters were clay, clay loam and 40 cm sandy loam, respectively. After lysimeters preparing, basil was planted in the lysimeter. Pb, Ni, Cu, Zn, Nitrate, phosphate and potassium concentration in leachate were measured after each watering.
The results indicate that soil columns (under basil cultivation) ability to keep Pb, Ni, Cu, Zn, Nitrate, phosphate and potassium concentration in wastewater. So Mean values of each of the above mentioned parameters were lower in the leachate compared to the wastewaters entering the lysimeter. Although during the use of wastewater, amounts of Pb, Ni, Cu, Zn, Nitrate, phosphate and potassium concentration in drainage increased but the value of this parameter is below the limits. The results showed the effect of type watering on mean values of all parameters (exception of Pb and Ni) was significantly. In terms of magnitude and significant, pattern of Zn, potassium, nitrate and phosphate were W3 =W2
According to the upward trend of heavy metals and nitrates in leachate, special care must be taken in using of wastewater (especially in raw wastewater). Because in future, with decomposition of organic matter, these elements can enter in groundwater and environment and be dangerous to humans