Seasonal assessment of water quality parameters in Mirim Lagoon, Rio Grande do Sul State, Brazil

Abstract

This paper aimed at to evaluate the qualitative effects of climatic seasonality in a subtropical lagoon, using Discriminant Analysis, as well to identify the most sensitive and responsible parameters for these changes. The Mirim Lagoon watershed is one of the main transboundary basins in South America and is of great economic importance for the region because its waters are used for irrigation of rice fi elds and for the potable water supply to populations close to it, in this way, these uses may affect the quality of the basin waters. The data used in the study were provided and collected by the Mirim Lagoon Development Agency. Water quality parameters were selected in a fi ve-year database and submitted to statistical tests that demonstrated their distinctions throughout the climatic seasons. The results showed that the parameters temperature, pH, dissolved oxygen, biochemical oxygen demand, total nitrogen and total phosphorus differ statically between the four climatic seasons. Were also identifi ed four discriminative parameters between the seasons, being them dissolved oxygen, biochemical oxygen demand, total nitrogen and total phosphorus. In this way, it can be concluded that the seasonality mainly affects anthropogenic pollution sources such as agricultural activities and domestic discharges.

Water quality assessment of the Educandos basin in Manaus, Brazil: use of the water quality index and multivariate statistical techniques.

“…A sazonalidade é um fator que geralmente influência na modificação do OD. A tendência é o regime maior de chuvas influenciar negativamente esse parâmetro (Girardi et al, 2016;Pinto et al, 2020). Para os resultados médios da bacia de Educandos podemos verificar modificações nesse parâmetro, principalmente, quando comparamos os resultados médios de OD no mês de julho de 2020 (20,35), com o mês de outubro de 2021…”

Análise da Influência de Fatores Climáticos na Concentração de Ferro e Manganês em Água Bruta Destinada a um Sistema de Tratamento de Água

“…Thus, with the objective of verifying if meteorological variables (temperature and rainfall) cause significant variation in the chemical variables (iron and manganese) studied, the significant test was carried out. For these analyzes, for p-value <0.05 the null hypothesis will be rejected, resulting in a significant variation (Pinto et al, 2020).…”

Water quality monitoring and assessment in coastal lagoons: Developing a protocol using a case study in Sainthamaruthu lagoon, Sri Lanka

“…Notably, Pinto et al. (2020) evaluated the surface water quality of Mirim Lagoon using multivariate statistical methods and discriminant analysis and identified dissolved oxygen, biochemical oxygen demand, total nitrogen, and total phosphorous as the key variables of water quality to be monitored. Meanwhile, CA helps select the key monitoring stations by grouping the stations with similar characteristics (Basatnia et al., 2018; Miyittah et al., 2020; Prusty & Farooq, 2020).…”