The pollution of environmental components by metallic trace elements around many mining sites is known around the world. This metallic pollution constitutes a serious public health problem and the bioaccumulation of these metallic trace elements by food plants is a major concern. This study highlighted the level of pollution by metallic elements in edible products of three plant species (zea mays, corchorus olitorius and manihot esculenta) regularly grown in the Tokpli limestone mining area. The analysis of metallic trace elements in soil and plant samples is respectively carried out by inductively coupled plasma microwave atomic emission spectrometer (ICP-AES 4200) and inductively coupled plasma atomic emission spectroscope (the Optima 80,000 ICP). The contents of various metallic trace elements were analyzed in the grains of zea mays, the leaves and stems of corchorus olitorius and tubers of manihot esculenta. The results show a high accumulation of most of these elements in edible products and in soils. These metallic elements in the soil would come from mining activity, the degradation of soils and other ecosystems, and the misuse of chemical fertilizers and pesticides. Their presence in edible products would be linked to the process of bioaccumulation by root and/or aerial ways.The pollution factors are of metallic trace elements (Hg, Fe, Pb, Al, Se…) in edible products such as zea mays (Hg: 2806.29; Fe: 1667.62; Pb: 1622.99), corchorus olitorius (Hg: 3463.24; Al: 2715.78; Fe: 1882.98) and manihot esculenta (Fe: 964.51; Hg: 670.13; Se: 539.26) plants grown around the Tokpli mining area are much higher than the thresholds recommended by the World Health Organization (WHO). Consumption of these products could expose consumers to chronic poisoning.

Zio River catchment drains many cities that it receives waste, domestic and industrial effluents and its waters used to supply drinking water from downstream to upstream. Some schools use it in school canteens without treatment. Meanwhile, no study on tools of water resources management is done in this basin and whole of Togo. To fill this gap, the environmental variables and benthic macroinvertebrates assemblages were investigated to assess ecological integrity of the Zio River and its tributaries that varied in disturbance from upstream to downstream. Macroinvertebrates were sampled during four campaigns from 42 sites selected to correspond with different human activities in the catchment. The AFNOR methods were used for physicochemical analysis. Multivariate analyses (PCA) were applied to characterize sites typology and FCA for similarity between sites or taxa. The result showed that physicochemical variables of downstream sites, with the lower level of dissolved oxygen (0.6mgO2/L) and high contents of ion NH4 (5.6mg/L), KMn (30.7mgO2/L) and high Conductivity (10670