The nutritional composition of six plant species after irrigation with treated wastewater and possible hazards by heavy metal accumulation

A field experiment was conducted investigating the possibility of using treated wastewater (TWW) on sites affected by water scarcity in summer, waterlogging during the wet season, and salinity. A corresponding pot experiment was conducted comparable to the field experiment in Kalaât Landelous. The same plant species (Atriplex nummularia Lindl., Eucalyptus gomphocephala DC., Acacia cyanophylla Lindl., Casuarina glauca Sieber ex Spreng., Cupressus sempervirens L., and Pinus halepensis Mill.) were grown with the same treatments. While, in the field the plants, elemental composition cannot be linked to inputs by TWW, this was studied under controlled conditions. Additionally, a control was established lower in salinity receiving tap water. The effect of TWW irrigation on macro- and microelement uptake by the six plant species was studied. The treatments were high soil salinity under drained saline (DS) conditions, high salinity under waterlogged saline (WS), and a drained non-saline control (DNS: EC = 3.0 dS/m, pH = 8.4). TWW application under DS treatment increased Na, Cl, Ca, Mg, N, P, and K in most plant tissues compared to the control. TWW application in WS treatment resulted in an increase in heavy metals. Cu and Zn showed the highest bioaccumulation factor (BAF). The BAF in different plant tissues followed the order: Cu > Zn > Mn > Cd > Ni > Co > Pb. The plants accumulated significant amounts of metals in their roots.