Ecohydrological systemic solutions for reduction of siltation, eutophication and dioxin-induced toxicity. The pilot study of the Asella BioFarm Park lake, Ethiopia

This study introduced the spatial pattern of PCDD, PCDF and dl-PCB concentration in the sediments of Ethiopian small river-lake system. Among the analyzed samples the highest contamination was observed in the lake littoral (222.11 ng kg−1 d.w.). The lowest concentration was noted at the outflow from the lake (26.65 ng kg−1 d.w.). The WHO-TEQ concentrations showed decreasing trend along the river-lake system with highest value in the inflow (2.32 ng TEQkg−1 d.w.) and the lowest at the outflow (0.55 ng TEQ kg−1 d.w.). The concentration of PCDD, PCDF and dl-PCB in the lake causes diseases among local population and prevents of use of water resources except from the outflow. Moreover the lake persistence and its ecosystem services provided for the local community were endangered by erosion of land and nutrient load from pastoral landscape, which could generate toxic algal blooms. For reversing the lake pollution the ecohydrological systemic solutions which integrated methodology to prevent all those threats to sustainable water and ecosystems was designed and implemented.