Assessment of nutrients and heavy metals content in soil and some vegetables cultivated in agricultural land around El-Khashab canal (Helwan-El Saff area)

Abstract

This investigation was conducted on nine sites at Helwan–El Saff area, Cairo, and Giza governorates (polluted area), and on three sites, in Metrabeaa village, Monofia governorate (control). This study aimed to assess the impact of wastewater irrigation on soil and plants. Water, soil, and plants samples were collected from El-Khashab canal (polluted water) and from Al-Bagoria canal (Nile water) and from the cultivated land sites adjacent to them. The values of EC, SAR, available N, OM and most of heavy metals (Fe, Mn, Zn, Cu, Co, Cr, and Pb) were significantly higher, in wastewater samples and soil under wastewater irrigation than control. There were significant differences regarding shoot and / or root content of N, P, K, crude protein, ash, heavy metals in all studied plants grown in the different sites. Garlic and onion accumulated most of studied heavy metals in their roots, while cabbage, lettuce and turnip accumulated high concentration of metals in their different organs, especially in their shoot; so, they could be used as phytoextractors. The heavy metals concentration in most of the studied plants exceeded the permissible level. This research declared that wastewater of El-Khashab canal improved soil fertility and OM content, but with risks as heavy metals may threaten sustainable agriculture. The agricultural lands in this area are not suitable for growing vegetables, especially leafy ones, due to their high ability to absorb, translocate and accumulate high concentrations of heavy metals in their edible parts. However, other plants might be cultivated in this area .