Quality of the aquatic environment of high Andean rivers evaluated through environmental indicators: a case of the Cunas River, Peru

Abstract

The quality of the aquatic environment of the Cunas River was evaluated through environmental indicators,
in two contrasting climatic periods. Anthropogenic pressures on the aquatic environment were identified, and
the BOD5 load contributed by the wastewater was determined. Water samples and benthic macroinvertebrates
were collected, and water quality and trophic status were determined. The BOD5 load contributed by
wastewater from fish, livestock, and urban activities was 23,27kg/ day, 284,31 kg/day and 349,70 kg/day.
The water quality of sectors S1, S2 and S3, according to the EPT, (Ephemeroptera, Plecoptera, Trichoptera),
BMWP (Biological Monitoring Working Party) and H’ (Shannon-Wiener diversity index) was good, regular
and poor, respectively. According to the INSF (National Sanitation Foundation Index of the United States
of America), the S1 and S2 presented good water quality and the S3 average water quality. According to the
chlorophyll a, the three sectors had low trophic levels. Therefore, the quality of the aquatic environment
supports significant anthropogenic pressures that have an impact on water quality and trophic status.