Abstract
The objective of this study was to evaluate the water quality of Carahá River in Lages (Brazil), using the concept of pollutant load and comparing the results with the water quality index. Thirteen points along the river were selected and eight collections were carried out over a period of 16 months. The parameters analysed were those required for the calculation of the water quality index (WQI). Flow measurements were also carried out, which enabled the calculation of the polluting load. The results showed that the WQI score ranges between 24.95 at the source and peaks at 40 at the outlet. The water classification, therefore, ranges from “very bad” to “bad”. The calculation of the pollutant load showed a constant disposal of contaminants into the river, which demonstrates that the quality of the water is continuously degraded. This information could not be obtained by analysing only the WQI, which presented a nearly constant quality at point 4 and beyond. The use of the calculation of pollutant load for Carahá River is, therefore, a tool for assessment of pollution that can provide more appropriate information for the water resources management.
Highlights
One of the most widely used tools for the assessment of water quality in rivers is the water quality index (WQI)
Water quality index The results of the WQI showed that water quality at point 1 is classified as “very bad” and at points 2 to 13 as “bad” (Table 1)
Even the point at the source (Point 1) is strongly impacted mainly by domestic sewage disposal. As this point presents the lowest water flow, there is a minimal effect of dilution, and the WQI was on average 24.89, classifying the water at this point as “very bad”
Summary
One of the most widely used tools for the assessment of water quality in rivers is the water quality index (WQI) This index was developed from a mathematical relationship that transforms the result of various analyses of physical, chemical and microbiological parameters into a single number. This simplifies the quality evaluation of the fresh waters (Maane-Messai et al, 2010). As an example of preliminary work, Egborge and Benka-Coker (1986) carried out their studies in the Warri River, Nigeria More recent studies, such as the Hou et al (2016) study of the Yellow River and Sun et al (2016) of the Courtyard River, both in China, and Abdel-Satar et al (2017) study of the Nile River in Egypt, highlight that WQI is still a useful tool for water quality assessment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
