Pollution Evaluation of the El Pueblito River in Queretaro, Mexico, Using the Water Quality Index

Abstract

This study evaluated the water pollution of the El Pueblito River by employing physicochemical parameters and biological indicators. Monitoring was conducted weekly during three months at seven sampling sites. To ease the representation of the results of this analysis, the water quality index (WQI) was calculated. The results obtained by the physicochemical analysis show the same trends as those of the analyses performed with bioassays using Daphnia magna and the WQI. The obtained values showed a deterioration of water quality from upstream to downstream due to the discharges into the river that occurred as it went through the city of Corregidora. The WQI values shifted from good water quality (83.00 ± 7.40) upstream to poor water quality (27.00 ± 0.85) downstream. This study also shows the utility of the WQI and how a Daphnia magna toxicity test can be an affordable and fast tool used to indicate high levels of pollution, such as in the case of El Pueblito River.