International Science Community Association Research Journal of Chemical Sciences 2231 - 606X 7 5 2017 05 18 Zinc toxicity and sequential extraction in water and sediments of tropical lake: A case study of Ahémé Lake in Benin 23 30 EN Haware Devendra J. 1 Food safety and Analytical Quality Control Laboratory, CSIR-CFTRI, Mysuru, India Kumar Ravi 2 Maharishi Markandeshwar University, Mullana, Ambala, Haryana, India D.S. Ramteke 3 EIRA Division, CSIR-NEERI, Nagpur, India Inam Farin 4 Department of Chemistry, Institute of Science, Nagpur, India Audi Deepa M. 1 Dhempe College of Arts and Science, Miramar, Panaji, Goa-403 001, India Saxena Reena 1 Department of Nanotechnology, Dr. K.N. Modi University, Newai, Rajasthan, India . Rahul 2 Chemical Engineering Department, Lakshmi Narain College of Technology, Bhopal, MP, India CHOUTI Waris Kéwouyèmi 1 Laboratory of Inorganic Chemistry and Environmental, Faculty of Sciences and technologies (FAST), University of Abomey-Calavi, Benin and Laboratory of Applied Hydrology, National Institute of Water (NIW), University of Abomey-Calavi, Benin BOCODAHO Lucinde 2 Laboratory of Applied Hydrology, National Institute of Water (NIW), University of Abomey-Calavi, Benin ADANDEDJI Firmin M. 3 Laboratory of Applied Hydrology, National Institute of Water (NIW), University of Abomey-Calavi, Benin KPAKO Boris Boniface 4 Laboratory of Applied Hydrology, National Institute of Water (NIW), University of Abomey-Calavi, Benin Dèdjiho Achille 5 Laboratory of Inorganic Chemistry and Environmental, Faculty of Sciences and technologies (FAST), University of Abomey-Calavi, Benin and Laboratory of Applied Hydrology, National Institute of Water (NIW), University of Abomey-Calavi, Benin TOMETIN Lyde 6 Laboratory of Applied Hydrology, National Institute of Water (NIW), University of Abomey-Calavi, Benin MAMA Daouda 7 Laboratory of Inorganic Chemistry and Environmental, Faculty of Sciences and technologies (FAST), University of Abomey-Calavi, Benin and Laboratory of Applied Hydrology, National Institute of Water (NIW), University of Abomey-Calavi, Benin > Research Paper 2017 4 11 2017 05 18 The presence of trace metals in surface water at concentrations above natural standards becomes a situation of increasing concern. Lake Ahémé, the second lake in Southern Benin with an area of 78km2 during the dry season and 126km2 during floods with a maximum depth of 2.35m did not remain on the fringe of this crucial situation. In fact, over half a century, we witness poor management of this ecosystem through activities that ensure little its ecological health. To understand this situation, water and sediment sampling work was carried out on four stations to characterize the chemical-toxicological standpoint Lake Aheme-Guezin. In order to better characterize the pollution degree of the ecosystem, we also evaluated the risk of toxicity in the water by the seeding method of Onion roots. Meanwhile, a study on the chemical speciation of zinc in sediment was carried out by the sequential extraction method of Tessier. Data processing was performed by the spreadsheet Microsoft Office Excel 2013; the collection card has been completed and digitized through the Google Earth and Arc-Gis software. Geographic coordinates were determined through Geodata conversion software. The toxicity tests results indicate a high toxicity degree in water and those of speciation gives much higher concentration standards on all the sampling points. These results show that human activities around the lake and within the complex asphyxiated by toxic metals from household waste with waste water (domestic and valves). Copyright@ International Science Community Association