eng Science and Education Publishing American Journal of Environmental Protection 2328-7233 2015-06-29 3 4 145 150 10.12691/env-3-4-5 ENV2015345 article Ayah M. a8yann@hotmail.com 1 Grybos M. 2 Bawa L. M. 2 Bril H. 2 Djaneye-Boudjou G. 2 Laboratoire de Chimie des Eaux, Faculté Des Sciences, Université de Lomé, Lomé, Togo Groupement de Recherche Eau Sol Environnement, Faculté des Sciences et Techniques, Université de Limoges, Limoges Cedex, France The aims of study is to distinguish the different origins of dissolved organic matter and emphasizes the spatial variations of dissolved organic matter quality in Lomé lagoon system composed by three lakes and Equilibrium canal. The results showed that, the three lakes of Lomé are dominated by biological dissolved organic matter (HIX < 4) except the site O11 (HIX = 5.75) with high biological activity (BIX included between 0.8 and 1). This high biological activity could due to the water contribution from north plateau and offshore bar. Apart from O11 and C4 the information brought by the ratio Iγ/Iæ shows that the dissolved organic matter of the lagoon is autochthonous and composed by labile organic compounds. Lomé lagoon system is composed in majority by humic substances with a small amount of microbial products. http://pubs.sciepub.com/env/3/4/5/env-3-4-5.pdf dissolved organic carbon aromaticity 3D fluorescence fluorescence indexes