Dharambir SinghRenu2018-11-142018-11-142018http://krishikosh.egranth.ac.in/handle/1/5810083416Earthworms are important components of the soil ecosystem, because their burrowing and feeding activities contribute notably to increase water infiltration, soil aeration and the stabilization of soil aggregates. Recent years have witnessed the contamination of soil ecosystem by heavy metals, which are considered as one of the major environmental issue. Presence of heavy metals in the soil environment adversely affects the earthworm populations resulting in an imbalance of the normal functioning of the various components of the ecosystem and due to this reason; the present study was carried out to investigate the effect of heavy metals on biomolecules and immune cells of earthworm, E. eugeniae. The results obtained showed the acute toxicity of two heavy metals individually as well as in combination of different concentrations on earthworms in terms of survival rate, growth (length and weight), reproductive efficacy, cocoon production, bio-molecules and coelomocytes. Maximum reduction in length (4.47 cm) and weight (0.41 g) of earthworm was seen in case of soil treated with Pb-0.06ppm as compared to control. Similar decrease in the survivability of earthworms was 43.35% and number of cocoons reduced upto 24.67 in case of Pb-0.06ppm contaminated soil. The maximum reduction in bio-molecules i.e. 16.23% in crude protein 28.55% in carbohydrate and 44.74% in crude lipid concentration was seen in earthworms treated with Pb-0.06ppm. In case of coelomocytes, there was a significant reduction in the total number of coelomocytes (67.39 %) in worms exposed to Pb (0.06 ppm). Similarly significant reduction in eleocytes, amoebocytes-I, amoebocytes-II, granulocytes-I and granulocytes- II was seen. Thus the study proves that Lead is more toxic and detrimental to earthworms as compared to Nickel.ennullThesis