Benthic Macroinvertebrates as Bioindicators for Assessing Water Quality in the Cañipia River, Cusco, Peru

Introduction. Benthic macroinvertebrates (BMIs) serve as bioindicators of water quality due to their sensitivity to physicochemical alterations from pollution. Objective. This study assessed water quality in the Cañipia River, Cusco, Peru, using BMIs as bioindicators.
Materials and Methods. Four monitoring stations were sampled in dry and wet seasons. BMIs were identified at the family level to calculate diversity and biotic indices. Physicochemical parameters and heavy metal concentrations in water and sediment were also analyzed.
Results. Elmidae and Chironomidae were the most abundant families. The BMWP/Col index classified water quality from critical to doubtful, the ABI index ranged from poor to good, and the EPT index indicated poor to moderate quality. The Simpson index showed fluctuating diversity (low to high in the low-flow season, moderate to high in the high-flow season), while the Shannon index indicated low to moderate diversity. The DMg index was higher in the wet season. Only the RCañi1 station, upstream of the formal mining area, exceeded Peruvian regulatory limits for Ba, Cu, Mn, and Zn in water. Canonical Correspondence Analysis (CCA) revealed seasonal relationships between metal concentrations and biotic indices.
Conclusions. The three biotic indices suggest moderate water quality impact in the Cañipia River, likely influenced by anthropogenic factors.