Effects of metal contaminated soils on Eisenia fetida (Savigny) at Ludhiana (Punjab), India

Abstract

The soil in the vicinity of stream of Buddah Nullah in Ludhiana, Punjab has been found to be contaminated with heavy metals. The objective of this paper was to conduct studies with earthworm Eisenia fetida (Savigny) exposed to five soil samples collected from different sites around the stream of Buddah Nullah, since no such work has been done using earthworm as bio- indicator of soil pollution in that area to check the hazardous effects of heavy metals on soil organisms. Metal levels were recorded higher in contaminated soil samples than threshold concentration in soil of campus field. Adult E. fetida were exposed for a period of 80 days to evaluate the effects of elevated levels of heavy metals i.e.0.29 ppm, 4.18 ppm and 2.29 ppm for cadmium, lead and nickel respectively on survival, growth, morphology and reproduction. Significant effects were observed on survival, growth and reproduction of the tested organisms along with various morphological abnormalities such as tail shedding, body fragmentation and extrusion of coelomic fluid. But no such deformity was observed in worms reared in reference soil of university campus field. Detrimental effects on rates of cocoon production and hatchling emergence were observed and a significant delay was also recorded in production of cocoons and emergence of hatchlings. Results of the study indicated that reproductive end points were more sensitive to elevated metal levels in contaminated soil than survival or weight change.