Heavy Metal Pollution and Biota-to-soil Accumulation Factor (BSAF) of in Situ Earthworms in Western Zone of Punjab, India

Earthworms are a key species in the terrestrial ecosystem as their responses to contaminated soil reflects the health of ecosystem functioning. The present study was undertaken to ascertain the effect of heavy metal pollution on in situ earthworm communities of Punjab, India. The presence of heavy metals in both soil and earthworm samples collected from all three districts of western zone of Punjab (Fazilka, Ferozepur, Bathinda). The content of heavy metal in soil samples and in earthworms collected from different locations followed the trend: Mn>Zn>Cu>Cr>Ni>Pb>As>Cd and Zn>Mn>Cu>As>Cr>Ni>Pb>Cd respectively. The heavy metal contents were higher in earthworms in comparison to soil samples. The oxidative stress in earthworms was highly significant and positive correlation for enzyme glutathione reductase with cadmium and chromium while negative correlation was observed of glutathione S transferase and glutathione peroxidise with chromium and manganese and copper, respectively. The biota-to-soil accumulation factor (BSAF) followed the trend: Cd>As>Zn>Cu>Pb>Ni>Cr>Mn. The current study is a step forward in the direction of in-situ study of earthworms and to understand the complex relations of various factors that together operate as determinants of bioaccumulation as opposed to the widely prevalent and controlled laboratory studies.