Bioaccumulation of heavy metals by earthworms from contaminated soils of vegetable fields in the vicinity of Buddha Nullah, Ludhiana, Punjab

The present study was aimed to analyse the status of heavy metals viz, Lead, Manganese, Cadmium, Nickel, Zinc, Chromium and Arsenic in soils and tissues of earthworms at vegetable crop fields in the vicinity of Buddha Nullah (a seasonal water stream highly contaminated with domestic and industrial wastes), Ludhiana district, Punjab. Three species of earthworms viz; Metaphire posthuma (Vaillant), Metaphire peguana (Rosa) and Lampito mauritii (Kinberg), inhabiting in these areas were found to accumulate certain amount of metals in their tissues. Three replicates each of soil and earthworm samples were collected from four study sites in the vicinity of Buddha Nullah (as contaminated sites) and one site at PAU (as reference site). The heavy metal concentrations in soil samples and tissues of earthworms collected from vegetable fields lying near Buddha Nullah site were significantly higher than that obtained from the reference site. Bioaccumulation factor for heavy metals was found to be higher in the L.mauritii as compared to other two species of earthworms, indicating it could serve as a possible bio-indicator of heavy metal contamination.