Influences of sewage sludge-amended soil on heavy metal accumulation, growth and yield of rocket plant (Eruca sativa)

Abstract

The application of sewage sludge (SS) in agriculture is a wastewater recycling method for soil fertilization. The aim of this study was to assess the influences of SS amendment rates (0, 10, 20, 30, 40 and 50 g kg−1) on the green-salad leafy plant Eruca sativa. The SS amendment increased soil salinity and organic matter and decreased soil pH. The heavy metal (HM) contents were below the permissible limits as recommended by the Council of the European Communities. An increase in E. sativa morphometric parameters was detected. The leaf, root and total biomasses of E. sativa increased at amendment rates 10, 20 and 30 g kg−1 . The applications of 40 and 50 g kg−1 negatively affected the biomass. The highest concentration of the measured HMs in the plant was detected at the 50 g kg−1 amendment rate. The bioaccumulation factors of Cd, Co, Cr, Fe, Mn, Ni, Pb and Zn were < 1.0, whereas those of Cu and Mo were > 1. The translocation factors for all HMs were < 1.0 except for Cd and Pb. Even though, SS increased the biomass of E. sativa, SS is not recommended as a fertilizer for E. sativa, since translocation factors of Cd and Pb were >1.