Integrated analysis of water quality from two rivers used for public supply in southern Brazil

Abstract

Aim This study aimed to evaluate the water quality of streams that are used for public supply, through an integrated analysis using a biotic index, as well as physicochemical and microbiological parameters. Methods The data were obtained monthly, from November 2014 to April 2015, at eight locations in two rivers in the south of Brazil. The landscape is predominantly rural, with the occurrence of small reforested areas, as well as yerba mate and grape cultivations. Macroinvertebrate samples were collected monthly using a Surber sampler. Water temperature and dissolved oxygen concentration were measured in the field using a portable oximeter. The following parameters were measured in the laboratory: pH, Turbidity, BOD, Conductivity and Nitrate. Results The evaluation carried out in the rivers revealed good water quality, but some sample sites presented reduced water quality. The waters of the Leãozinho River were classified as doubtful at site 1 and as good at sites 2, 3 and 4. Ligeirinho River presented an acceptable rating at sites 1 and 4 and was classified as good at sites 2 and 3. The BMWP’ index was significantly correlated with the abundance of macroinvertebrates, EPT richness and BOD. The abundance and richness of macroinvertebrates in Leãozinho and Ligeirinho Rivers were associated with the physical, chemical and microbiological parameters. Conclusion This study reinforces the importance of biomonitoring in the evaluation of water quality for human consumption, considering that environmental management and monitoring practices should integrate physicochemical, microbiological and biological parameters.

Pesticide Determination in Water Samples from a Rural Area by Multi-Target Method Applying Liquid Chromatography-Tandem Mass Spectrometry

“…33 A study performed in two rivers at the Rio Grande do Sul State showed conductivity values lower than 90 µS cm -1 for samples considered as natural waters. 35 Values higher than 100.00 µS cm -1 , as in cases of SP 3, SP 4 and SP 9 with results in the range of 120.30 to 421.00 µS cm -1 , may indicate environmental impact in natural water. SP 5 conductivity stands out due to the raised levels observed in the samplings in September and December ( Table 2) with an increase more than 600 times the value of 1200.00 µS cm -1 , pointing out pollution.…”

“…The pH value is one of the most important physicochemical parameters evaluated in this work since the persistence and the partitioning of the pesticides molecules in the aqueous media is directly related to it. 35 The pH range observed was 5.6 to 7.44, of which six samples were considered outliers accordingly to the limit range (6.00-9.00). 21 In this pH range, several compounds still persist on their non-ionized form due to the pKa value, promoting their association with the organic matter available.…”

Impact of urbanization on the water quality of the Uberaba River and tributaries

“…The life cycle of macroinvertebrates is affected by environmental disturbances, fact that enables the easy identification of adverse effects caused by such disturbances on the environment (BUSS, BAPTISTA;NESSIMIAN, 2003). Several researchers have recently used benthic macroinvertebrates as water-quality bioindicators (BLAKE;RHANOR, 2020;CHAGAS et al, 2017a;MEZGEBU;LAKEW;LEMMA, 2019;NASCIMENTO;ALVES-MARTINS;OCHIENG;ODONG;OKOT-OKUMU, 2020, PEREIRA et al, 2020SUDARSO et al, 2021).…”