Proposal of a Water-Quality Index for High Andean Basins: Application to the Chumbao River, Andahuaylas, Peru

David Choque-Quispe,Miriam Calla-Florez,Antonieta Mojo-Quisani,Edward E Barboza-Palomino,Henry Palomino-Rincón,Aydeé Kari-Ferro,Diego E Peralta-Guevara,Gloria I Barboza-Palomino,Lourdes Magaly Zamalloa-Puma,Yudith Choque-Quispe,Edgar L Martínez-Huamán,Aydeé M Solano-Reynoso,Edgar G Aronés-Medina,Sandro Froehner,Miluska M Zamalloa-Puma

doi:10.3390/w14040654

Abstract

The water from the high Andean rivers is peculiar due to its composition and the geomorphology of its sources, and naturally or anthropogenically contamination is not discarded along its course. This water is used for agriculture and human consumption, therefore knowing its quality is important. This research aimed to proposing and formulate a water-quality index for high Andean basins through the Delphi method, and its application in the Chumbao River located in Andahuaylas-Peru. Forty-three water-quality parameters were evaluated through the Delphi method, and the water-quality index (WQIHA) was formulated with a weighted average of the weights of the selected parameters, it was compared with the WQI Dinius. For this purpose, ten sampling points were considered along the Chumbao River located between 4274 and 2572 m of altitude and the WQIHA was applied. In addition, field and laboratory analyses were carried out in 2018, 2019, and 2021, in dry and rainy seasons. Twenty parameters were grouped in the physicochemical sub-index (SIPC), heavy metals sub-index (SIHM), and organic matter sub-index (SIOM). Each group contributed with weights of 0.30, 0.30, and 0.40, respectively, for the WQIHA formulation. The SIPC and SIOM showed that the areas near the head of the basin presented excellent and good quality, while the urbanized areas were qualified as marginal to poor; SIHM reported good quality in all points and seasons. Regarding the WQIHA, the index shows good quality in the zones above 3184 m of altitude, contrasting with poor quality downstream, decreasing notably in both seasons, suggesting continuous degradation of the water body.

Highlights

The headwaters from the High Andean Rivers are located in the Andes Mountains above 4000 m of altitude
It was observed that the parameters temperature, turbidity, pH, conductivity, hardness, nitrates, phosphates, zinc, Dissolved oxygen (DO), BOD5, thermotolerant, and total coliforms had an appreciation of 100% (Table 6), whereas the parameters TDS, color, nitrites, ammonium, lead, and iron showed a coincidence of 85.7%, and the remaining with 71.4%
This is an important indicator in surface and river water quality [10,12,14,17,29,40,51]

Summary

Introduction

The headwaters from the High Andean Rivers are located in the Andes Mountains above 4000 m of altitude. Those are forming water bodies due to the melting of glacial ice caps [1,2,3]. The problem can be aggravated when rivers pass through urbanized areas where contamination with organic matter stormwater runoff contributes further [8,9,10,11]. Rivers in urban areas are affected by untreated wastewater discharges from clandestine landfills, sanitary landfills, and industrial waste [12,13,14,15,16].

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Results

Conclusion