“…Of greater concern, increasing concentrations of nitrate (NO3-N) in soil solution due to TWW irrigation have often been reported (Polglase et al, 1995;Smith and Bond, 1999;Gwenzi and Munondo, 2008), representing one of the main challenges for the sustainable land application of effluents (Bond, 1998;da Fonseca et al, 2007a). Otherwise, the soil-plant system, if adequately managed, encourages retention of TWW components mainly due to the incorporation of elements in the dry matter (DM) of plants (Bouwer and Chaney, 1974;Vaisman et al, 1981), leading to decreasing element concentrations in ground and surface waters (Feigin et al, 1978). Harvest and removal of plant material withdraw the accumulated elements, which further contribute to prevent leaching of elements, mainly nitrogen (N) and enrichments in the subsoil solution and the groundwater concentrations ( Quin and Forsythe, 1978;Hook, 1981).…”