Variations on copper bioavailability in soil treated with copper-enriched sewage sludge

Abstract

Copper behavior and bioavailability in a red Latosol treated with Cu-enriched sewage sludge were investigated. Results showed that sewage sludge increases nutrient and organic matter concentration in the soil. In sludge-amended treatments, bioavailability to lettuce plants was reduced due formation of organic complexes. In this case, plant productivity was affected only by soil acidity. Phytotoxicity was noticed in treatments without sludge and with high amounts of copper. Metal levels in roots, instead of in plant shoots, show a good fit with bioavailable copper estimated using the Mehlich-1 solution, commonly used in routine analyses, even at high metal levels.