Effect of Earthworm on Bio-availability of Pb and Cd in Soil

On the basis of the experiment raising earthworms in contaminated soil,analysis was made on the bioavailability of Pb and Cd in soil and the accumulation of Pb and Cd in earthworm.The results showed that the activities of earthworms significantly increased the contents of acid extractable Pb and Cd,however,it did not affect the fractions of Pb or Cd for the oxidizable form.The earthworm and the vermicompost exhibit strong accumulation ability on Cd,and the Cd accumulation of earthworm increases gradually with the increased Cd concentration;the lead accumulation of unit weight of earthworm is significant with lead concentration grads.The contents of acid extractable Pb and Cd in vermicompost were higher than them in the soil.