Uptake and Metal Transfer from Biosolid-Amended Soil to Tomato (Solanum lycopersicum Mill L.) Plants

This study investigates the inputs of total and available metals from biosolid-amended soil, as well as their accumulation in tomato plants (Solanum lycopersicum Mill L.) and subsequent translocation. A greenhouse study with tomato seedlings grown in soil amended with two organic waste types (anaerobically digested thermal drying sludge and anaerobically digested municipal solid waste compost) was conducted. From an environmental viewpoint, the potential risk of metal uptake by crops must be considered. The results indicated significant increases in Cd, Cu and Zn in soil, even though their available fraction was not modified with Cu and Zn, and the Cd fraction significantly decreased. Roots showed the highest metal concentrations, but the differences between the plants grown in the biosolid-amended or control soils were not always significant. The root system acted as a barrier for Cr, Ni and Pb. No significant variations in the concentrations of the metals in the tomatoes grown in biosolid-amended or control soils were observed. Soil-to-plant metals transfer was in this order: Cu (1.14-2.85) > Cd (1.33-2.17) > Zn (1.4-1.48). The highest and lowest BAFs were observed in roots and tomatoes, respectively. According to the result obtained in the translocation and bioaccumulation factors, Cd was the heavy metal that indicated the greatest mo from soil. The canonical correlation analysis proved a highly significant relationship in the soil/ plant system, which was strongly and positively related with Cd, Cu and Zn. Biomass production was similar regardless of treatment, but some differences were found for aerial plant parts as regards metal accumulation, whereas the metal levels in tomatoes were negligible for all treatments.