Contents: 1.Assessment of heavy metal pollution in river Tawi and its effect on proximate quality of fish/Monika Sharma, Roopma Gandotra and Sapnajangra. 2. Histological changes in larvicidal fish due to organophosphate/Sabiha Khan. 3. Effect of methyl parathion (an Organophosphate)on biochemical contents of fresh water cat fish heteropneustes fossilis (Bloch)/Bheem Rao. T, Thirupathi. K and Venkaiah. 4. Acute toxicity of detergent D1 and D2 Powder on a catfish mystus Seenghala from Manjara River Near Kollam, Dist. Osmanabad (M.S.)/Kamble S. M., Bhagwan H. K., Chinte D. N.,Biradar S. R. and A. H. Kamble. 5. Screening of traditional medicinal plants against aedes aegypti Linn. (Diptera: Culicidae), a dengue fever vector/A.N. Anoop kumar, Sreedev Puthur, Sharrel Rebello, Embalil Mathachan, Aneesh, Prabha Kumari,Vijay Laxmi Saxena. 6. Comparative seasonal estimation of heavy metalsin two different lotic water bodies of Jammu (J&K)/Roopma Gandotra, Sapana Jangral and Monika Sharma. 7. A natural alternative approach to synthetic Insecticides/B.S.Chandel. 8. Effect of pyrethroid on physiology of Biofauna/Prafullata V. Kolkhede. 9. Scindapus officinalisan eco-friendly arsenal against Aedes aegyptia potential dengue fever vector(Diptera: Culicidae)/Sreedev Puthur, A.N Anoop Kumar, Sharrel Rebello, Embalil Mathachan Aneesh, Prabha Kumari, Vijay Laxmi Saxena. 10. Passage of ammonia through the mitochondrial membranes and the blood–rain barrier in Ctenopharyngodon idella due to ammonia toxicity/M.Vasantha Lakshmi and B. Chakravarthi. 11. Study of Biochemical parameters of Eudriluseugeniae (Kinberg) in various organic wastes supplemented with Probiotics/Mujeebunisa, M., Saravanan,S., Divya, V.,Vasanthakumar, D and Aruna, D. 12. Isolation and Molecular typing of Aeromonas Isoltes from river Ganga and Mandakini/Mitali Dhiman, S.S. Mishra, R.C Tripathy and B.K. Dwivedi. 13. Effect of Phosphomidon in Summer Season on Protein Alterationin Fresh Water Snail Viviparus bengalensis/Sopan L Erande. 14. Influence of various organic wastes on certain biochemical parameters of carbohydrate metabolism in Eudrilus eugeniae (Kinberg)/Divya. V., Mujeebunisa. M., Saravanan.S.,Vasanthakumar D and Aruna. D. 15. The dietary effect of Melia dubia leaf on Biochemical-Protein Parameter of Tilapia (Oreochromis mossambicus)/Jansi.A and Rosaline Mary.16. Effect of sewage water and sago effluent dueto Thirumanimuthar river and haematological and SEM analysis in the freshwater fish Cirrhinus mrigala/J.Vasanthi. 17. Histopathological effect of endosulfan on testes of Swiss Albino Mice and Bioremediation through amla/Kailash Kumar, Poonam Kumari and Bindu Kumari Singh.18. Laboratory selection and Detoxification enzymeanalysis of Carbofuran resistant line of Culex quinquec fasciatus Say, the filarial vector/Aneesh E M, Sharel Rebello1, Vijayan V A, Prabha Kumari C, Vijay Laxmi Saxena. 19. Toxicity of tannery effluent on biochemical parameters of the fresh water fish Oreochromis mossambicus/T. Manimegalai1, A. Arunachalam, Soorya Sukumaran, K. Raguvaran, R. Maheswaran. 20. Protective Role of green tea extract against cypermethrin in fresh water fishes Heteropneustes fossilis/Kannez Zahra, Akanksha Singh and Surbhi Yadav. 21. Effect of lambda-cyhalothrin and Imidaclopridon oxygen consumption of the freshwater Bivalve, Lamellidens marginalis/Poonam Ahire, Pramila Bhamre, Ashok Desai. 22. Histopathological changes in Liver of fish nemacheilus botia exposed to sublethal concentrations of organophosphorous in secticide monocrotophos/J.D.Vasait. Toxicology is a discipline involved adverse effects of chemical substances on living organisms, dose of chemical substances and its effect on exposed organisms. With rapid growth in industrialization, urbanization, pesticides usage in irrigation resulted in environmental pollution (air, water, soil pollution).Due to this, mainly water bodies get contaminated as they receives the effluents from industries, domestic waste, agricultural runoff which directly effects the aquatic organisms. The material in this book brings together all the information on comparative, seasonal estimation of heavy metals and its effects on the aquatic organisms, toxicological studies of detergents on cat fish, ammonia toxicity, effect of medicinal plants against dengue fever vector, natural insecticides influences of organic waste on metabolic activity of aquatic organisms and bio-remedial studies. We are thankful to all the authors and other contributors for giving their valuable time and data. They are responsible for the work presented in the paper and if any plagiarism question arises they are answerable.