Assessment of potential reference sites for evaluating the ecological status of subtropical and temperate Brazilian lotic systems using the epilithic diatom community.

Autor: Freitas NCW; Environmental Technology Graduation Program, University of Santa Cruz do Sul - UNISC, Avenida Independência, 2293, CEP, RS, 96815-900, Santa Cruz do Sul, Brazil., Heinrich CG; Environmental Technology Graduation Program, University of Santa Cruz do Sul - UNISC, Avenida Independência, 2293, CEP, RS, 96815-900, Santa Cruz do Sul, Brazil., Etges T; Water Resources Management and Regulation of ProfÁgua, Federal University of Rio Grande do Sul - UFRGS, Avenida Paulo Gama, 110, CEP, Porto Alegre, RS, 90040-060, Brazil., de Souza Celente G; Environmental Technology Graduation Program, University of Santa Cruz do Sul - UNISC, Avenida Independência, 2293, CEP, RS, 96815-900, Santa Cruz do Sul, Brazil., Lobo EA; Environmental Technology Graduation Program, University of Santa Cruz do Sul - UNISC, Avenida Independência, 2293, CEP, RS, 96815-900, Santa Cruz do Sul, Brazil. lobo@unisc.br.
Jazyk: angličtina
Zdroj: Environmental science and pollution research international [Environ Sci Pollut Res Int] 2021 Feb; Vol. 28 (7), pp. 8698-8708. Date of Electronic Publication: 2020 Oct 17.
DOI: 10.1007/s11356-020-11136-w
Abstrakt: This research aimed at determining reference sites in southern Brazilian lotic systems, using the Water Quality Trophic Index (WQTI), based on epilithic diatom communities. Within the period of 2012 and 2016, 140 epilithic diatom samples from seven sampling sites within the spring area of the Andreas Stream Hydrographic Basin, Vera Cruz County, RS, Brazil, were analyzed quarterly. Similarly, from 2012 and 2014, water samples in these sampling sites were collected for determination of physicochemical and microbiological parameters, such as water temperature, pH, turbidity, dissolved oxygen, biochemical oxygen demand, nitrate, phosphate, total dissolved solids, and fecal coliforms. The results indicated the occurrence of two diatom samples groups with significant differences (p < 0.05). Group 1 (sampling sites P1, P4, and P5) was classified in the oligotrophic category with an average WQTI of 1.3 ± 0.2, while group 2 (sampling sites P2, P3, P6, and P7) was classified in the β-mesotrophic category with an average value of 2.0 ± 0.4). Achnanthidium minutissimum and Platessa hustedtii the dominant species were classified as oligotrophic taxa. Thus, we proposed the upper limit of the first interval of the WQTI score scale, equal to 1.5, as a reference value to differentiate the limits between the "high" and "good" ecological status to determine "reference sites" for subtropical and temperate Brazilian aquatic systems. The physical, chemical, and microbiological water quality evaluation gives support to this proposal, as far as the results indicated a significant improvement in the water quality, classifying sampling sites P1, P4, and P5 as having good quality appropriate for multiple uses.
Databáze: MEDLINE
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