Bioaccumulation of Cobalt and Lead by Earthworm Eisenia fetida from Sewage Sludge with Different Cattle Dung during Vermicomposting

The aim of the present study was to investigate the heavy metals accumulated by earthworm Eisenia fetida from sewage sludge (SS) with different animal's dung during vermicomposting. The cobalt (Co) and lead (Pb) were significantly decrease in vermicompost from all the combination of SS; maximum decreased Co (84.83%), and Pb (83.69%) from the SS as combination of BD+SS (in ratio 1:1) and HD+SS (in ratio 1:3) respectively. The Co and Pb was significantly increase (4.34% and 7.14%) in earthworm body (10.127±0.003 and 14.319±0.005 mg/kg) when treated in the combination of PD control and BD+SS in 1:3 ratio respectively. The Pb was also observed in the earthworm body after treatment of SS with different combination of animal dung. The Co and Pb conc. were observed in earthworm body before inoculation at the level of (9.687±0.003 mg/kg) and 13.296±0.011 mg/kg respectively. These metals concentration were decreased in vermicompost resulted from as significantly increase in earthworm body as zooaccumulation during vermicomposting. The earthworm Eisenia fetida also important macro-organism was responsible for the reduction of heavy metals due to the accumulation in their body tissue.