Toxicity and uptake of heavy metals of sewage sludge by beans (Phaseolus vulgaris L.) were evaluated in green house experiments. Treatments consisted of 1,0 ; 2,0 and 5,0% (m/m) of dry sewage sludge, collected from Londrina (Bom Retiro and ETE-Sul) and Curitiba (ETE-Belém and RALF). Bean ( variety IAPAR 57) was sown three times at 0, 120 and 240 days after the treatments have been applied. Contents of Cd, Cr, Co, Cu, Ni, and Pb in bean tissues cultivated with 5,0% (m/m) of all sewage sludge were similar to the control and Ba contents were reduced by increasing the quantity of sewage sludge in the soil. The Zn content in tissue bean incresed from 86 mg kg-1 of control to 462 mg kg-1 by applying 5% (m/m) of sewage sludge in soil, but plant beans did not show toxicity symptons. The addition of 5% (m/m) of sewage sludge increased Mn content in plants, from 193 mg kg-1 of control to 1.960 mg kg-1, showing toxity in bean leaves when the contents were more than 500 mg kg-1. The addition of sewage sludges in soils increased only available Zn carbonate and Cu organic species.
Phaseolus vulgaris L.; heavy metal; metal toxicity; metal fractionation
