Accumulation of heavy metals during vermicomposting by earthworm Eisenia fetida

Earthworms form one of the major macrofauna among soil biota to maintain dynamic equilibrium and regulate soil fertility. Their existence depends on adequate moisture, soil texture, pH, electrolyte concentration and food source in the given ecosystem. The present study focusses primarily on the potential of Eisenia fetida Savigny to accumulate heavy metals from contaminated soil during vermicomposting. Samples of contaminated soil were collected from five different sites in the vicinity of Buddha Nullah at Ludhiana, and upon analysis Lead, Chromium and Nickel were recorded as the prominent metals of the area. The potential of bioaccumulation was tested by adding metals to artificial soil in ratios similar to those found at sites and earthworms were released into the trays. The results indicated that bioaccumulation of heavy metals (Pb, Cr, Ni) takes place in earthworm tissue. The percent remediation in soil with highest dose of lead was 5.54%, 4.53% for chromium and 48% for nickel indicated that as compared to other metals nickel was remediated easily.