A study carried out by H C Agarwal, P K Mittal, K B Menon and M K K Pillai of the department of zoology, University of Delhi, published in August 1985, traced DDT residues in water, bottom sediments and certain organisms from four different sites in the river. Total DDT residues ranged from 0.04 to 3.42 microgram per litre in water; 0.007 to 5.63 milligram per kg (mg,kg) in bottom sediments; 0.05 to 15.24 mg,kg in various invertebrates and 0.54 to 56.31 milligram per kg in fish.