Analysis of Achyranthes aspera leaf extract and environmental safety evaluation to 1

25 Background: Although plant molluscicides are biodegradable and less toxic to higher 26 animals, unregulated applications could affect other non target aquatic species. Eco 27 toxicological studies are required to evaluate whether they are safe to those economically 28 and ecologically important fish species. According to previous studies, Achyranthes 29 aspera is a molluscicidal plant with LC 90 of 96.5 mg/L and the current study is to 30 investigate its toxic effect to Nile tilapia fish fingerlings, Oreochromis niloticus . 31 Methods: Seven fish fingerlings were exposed to serial dilutions of A. aspera leaf 32 aqueous extract for 96 hours in duplicate setup. Phytoconstituents were identified by GC- 33 MS and lethal concentrations were determined by probit model. The NOAEC was 34 determined by hypothesis testing on the survival data. 35 Results: The respective piscicidal LC 1 , LC 10 and LC 50 values were 897.4, 1063.9 and 36 1310.74 mg/L. The NOAEC was 1100 mg/L (p>0.05). GC-MS analysis revealed 12 37 phytoconstituents including a monoterpene. 38 Conclusion: The result shows that A. aspera is non toxic and hence is safe to Nile tilapia 39 fish especially at its molluscicidal dose limit (96.5 mg/L LC 90 ) corroborating to the plant’s 40 target specific molluscicidal potential. 45 46 47