International Science Community Association Research Journal of Chemical Sciences 16 2 2026 06 18 Assessment of sedimentary Phosphorus mobility in Zone II of the Ébrié Lagoon system using an Optimized Sequential extraction method 42 52 EN Gupta Swaroopa Rani N. 1 Department of Chemistry, Brijlal Biyani Science College, Amravati, Maharashtra India Chaudhari Harshida G. 1 Department of Chemistry, Shree Jayendrapuri Arts and Science College, Bharuch, Gujarat, India Vashi Rajendra T. 2 Chemistry Department, Navyug Science College, Rander Road, Surat, Gujarat, India Sakhare D. T. 1 Department of Chemistry, Shivaji, Art’s, Comm. & Science College Kannad. Dist. Chhatrapti Sambhajinagar-431103, MS, India Gupta Swaroopa Rani N. 1 Department of Chemistry, Brijlal Biyani Science College, Amravati, Maharashtra, India Hicham Abbas Cheick 1 Doctoral School of Science, Technology and Sustainable Agriculture (ED-STAD), 01 BPV 34 Abidjan, Côte d'Ivoire and Laboratory of Reaction and Constitution of Matter (LCRM), UFR SSMT, Félix Houphouët-Boigny University, 22 BP 582 Abidjan 22, Côte d'Ivoire Konan Yao Marcel 2 Laboratory of Reaction and Constitution of Matter (LCRM), UFR SSMT, Félix Houphouët-Boigny University, 22 BP 582 Abidjan 22, Côte d'Ivoire Soumahoro Sangaré Naminata 3 Doctoral School of Science, Technology and Sustainable Agriculture (ED-STAD), 01 BPV 34 Abidjan, Côte d'Ivoire Arthur Konan Kouadio Fabrice 4 Laboratory of Reaction and Constitution of Matter (LCRM), UFR SSMT, Félix Houphouët-Boigny University, 22 BP 582 Abidjan 22, Côte d'Ivoire Jean-Claude Drida Bi Bénié 5 Doctoral School of Science, Technology and Sustainable Agriculture (ED-STAD), 01 BPV 34 Abidjan, Côte d'Ivoire and Laboratory of Reaction and Constitution of Matter (LCRM), UFR SSMT, Félix Houphouët-Boigny University, 22 BP 582 Abidjan 22, Côte d'Ivoire > Research Paper 2026 2 4 2026 06 18 The present study aims to assess the mobility of sedimentary phosphorus in Zone II of the Ébrié Lagoon system by employing an optimized sequential extraction method specifically adapted to these sediments. Five samples were collected monthly over a one-year (January to December 2024), yielding a total of 60 samples. The seasonal mobility of sedimentary phosphorus in this estuary was assessed using the method proposed by Abbas et al. The results highlight a predominance of phosphorus bound to iron, followed by phosphorus bound to aluminum, with mean seasonal concentrations ranging respectively from 366.7 ± 14.5 to 493.3 ± 5.3 mg/kg and from 271.5 ± 5.1 to 351.9 ± 6.8 mg/kg. In contrast, phosphorus associated with (oxy) hydroxides, authigenic phosphorus, and detrital phosphorus exhibited the lowest mean seasonal concentrations, all below 10 mg/kg. Overall, sedimentary phosphorus mobility proved to be substantial during the study period and is likely to exert a significant influence on the trophic status of the estuarine waters. Copyright@ International Science Community Association