Evaluation of the ecological and environmental quality of the water from the Jequetepeque river in the San Juan - Chilete section of the department of Cajamarca

Abstract

The present research was focused on the analysis of the water quality of the Jequetepeque river in the department of Cajamarca, Peru. The analysis included the evaluation of the ecological and environmental water quality of the Jequetepeque river in the San Juan - Chilete section, where physicochemical parameters were analyzed (nitrates, nitrites, phosphates, pH, conductivity, temperature, dissolved oxygen (BOD5), fluorides, chlorides, bromides, sulfates, total dissolved solids and turbidity), microbiological parameters (nitrates, nitrites, phosphates, pH, conductivity, temperature, dissolved oxygen (BOD5), fluorides, chlorides, bromides, sulfates, total dissolved solids and turbidity), microbiological (thermotolerant and total coliforms), and the inventory of benthic macroinvertebrates for the application of biotic environmental quality indexes (BMWP/Col, BMWP/Bol and EPT) and the United States NSF environmental quality index. For the investigation, 4 samplings were carried out, 2 in time rain and 2 in dry season, in which a total of 28 samples were collected, in which the collection method of identification and analysis of biological communities of the Ministry of Environment for the collection of benthic macroinvertebrates and for the water sampling, the protocols and testing techniques of the Regional Water Laboratory, a testing laboratory accredited by the Peruvian accreditation body (INACAL), were applied. Additionally, the relationship between these parameters and the results of the biotic indices was analyzed. The water was characterized by an alkaline pH and the parameters showed an increasing trend from upstream to downstream. The pH and thermotolerant coliforms did not comply with the Peruvian national water quality standards environmental water quality standards Ds 004-2017 of the Peruvian Ministry of the Environment, in some sampling points (mostly in the Chilete area), in both seasons (low water and rain). Three classes, 11 orders and 30 families of benthic macroinvertebrates were found. The final average results of the indexes and AQI in low water and rainy season respectively are BMWP/Col- 67 and 51; BMWP/Bol 61 and 47; EPT 4 and 4; and NSF AQI 59 and 60. It was concluded that the water is moderately contaminated, and there is a concordance and relationship between the results of the physicochemical and microbiological parameters, biotic indexes and the NSF AQI. The main source of contamination in the area is organic pollutants from wastewater and solid waste.