Biotic aspects of suspended solid reduction in sedimentation ponds.

The reduction of suspended solids is an important aspect of water management, especially in the mining industry. The ecological potential of sedimentation ponds has been identified, but many aspects of the coexistence of ecological and technological functions of these reservoirs are still unresolved. The aim of the study was to determine the effectiveness of suspended solid reduction in an open pit mine drainage system under the influence of biotic factors, including fish, taking into account the hydrochemical background. The dynamics of biotic factors and the sedimentation process were identified using the normalized total suspended solid reduction index (TE) and the trophic group status (TGS) indices of planktivorous, benthivorous, and carnivorous fish. The hydrochemical background in both ponds provided similar habitat conditions for biota and suspended solid reduction. Although a moderately trophic ecosystem has developed, the typical relationship between water transparency (SDD) and chlorophyll a concentration characteristic of natural waters was not observed. The sedimentation complex was found to be highly effective in reducing total suspended solids by 89-93%. Spatial variation of sedimentation rates was related to the ichthyobiotic factor, mainly to the biomass of bentophages and the status of this trophic group in the fish community. Stable relationships in the structure of the ichthyofauna with a balanced proportion of planktivorous fishes favored the sedimentation process. The results obtained are part of the development of research on the possibility of combining the technological function of artificial ponds with other applications and ecological benefits for industrialized areas.