Some Chemical Properties of Soil Affected by Long-Term Application of Primary Treated Wastewater

Abstract

Effect of irrigation with primary treatedwastewater on some chemical properties of soil was the main purpose of' this investigation. Eight soil profiles were chosen fromAbou-Rawash farm (Giza Governorate)those profiles represent soils under different periods ofsewage water utilization (0, 10, 20, 25 and 50 years), respectively. The chemical analysis ofprimary treated wastewater showed that total salt concentration and heavy metal content was within the safe limits. Thus, wastewater remained within permissible limits for use as irrigation water. Soil analysis revealed that nitrogen, phosphorus and potassium content were high in primary treatedwastewater irrigated soils compared to non-wastewater irrigated soils. The soil pH and EC decreased as a result of wastewater irrigation. Data indicate that the availability of Fe, Mn, Zn and Cu in soil increased by irrigation with primary treatedwastewater compared to control soil; the highestaccumulation of micronutrients were found in the surface layer in soil irrigated with primary treated wastewater for fifty years and the lowest in the sub-surface layers of control soil. Based on our study, the concentration of heavy metals (Pb, Ni, Mo, Cd, and B) was higher in top layers of primary treatedwastewater irrigated soil compared to those not irrigated with wastewater (control soil). It has been reported that high concentration of heavy metals in primary treatedwastewater leads to an increase of their content in soil. Also, the enrichment factor of the heavy metals in soil irrigated with primary treatedwastewater were higher and taken this sequence of Ni >Pb> Cd > Mo > B.