Nematode Community Structure and Efficacy of the Free-Living Nematode Metarhabditis andrassyana as a Toxicological Assay Organism

A survey of agricultural fields around Yamuna river in Faridabad, Haryana was conducted to study the community structure of the soil inhabiting nematodes. A total of 32 genera belonging to 8 orders and 21 families were recorded. In terms of number of genera, order Rhabditida was most frequent. The trophic diversity index (TDI) ranged from 1.2–1.4 (1.32 ± 1.11), Shanon's Diversity Index (H^’) varied from 1.1–2.9 (2.70 ± 0.15) and the maturity index (MI) ranged from 1.23–1.45 (1.36 ± 0.23). The low MI value indicated that it is a less stable and disturbed ecosystem. The efficacy of the free-living nematode Metarhabditis andrassyana as a toxicological assay organism was studied using lead, mercury, cadmium and copper as test substances. Testing of the toxic effect of the four heavy metals revealed that lead was the most toxic among all tested metals.