Macroinvertebrados bentônicos como ferramenta de análise biológica de qualidade ambiental da bacia hidrográfica do Rio Santo Antônio (MG)

Abstract

Most water bodies suffer impacts from human actions, such as disordered use and occupation of soil, which comes from the disorderly growth of urban centers, considered one of the main causes of degradation of rivers and lakes due to waste dumping, industrial and sanitary sewage without correct treatment. Aware of this problem, this study aims to evaluate the use of benthic macroinvertebrates as bioindicators of environmental quality, in the Rio Santo Antônio/MG watershed. Benthic macroinvetebrates were collected in 8 points distributed along the Santo Antônio river watershed. In addition to identifying macroinvertebrates, physical, chemical and microbiological analyzes of the water were carried out at the collection points in order to better understand the results acquired by the bioindicators, in addition to the application of the Rapid Assessment Protocol (PAR), to classify the environmental characteristics of each location. collected. Results such as land use and occupation in the basin and its percentage of each use were acquired along with the representative map. By using the Rapid Assessment Protocol it was possible to determine that collection point number 4 located in the municipality of Carmésia/MG and collection point 8 in the municipality of Naque/MG, were classified as impacted and the others classified as natural. From the samples of benthic macroinvetedrates collected, 134 individuals were identified in total, being classified into 3 phyla, Arthopoda, Annelida and Mollusca, 4 classes being: Bivalvia, Gastropoda, Insecta and Oligochaeta, totaling 6 orders. The presence of the Oligochaeta class stands out, in addition to Diptera and Bivalvia, these are considered organisms that live in environments where environmental disturbances occur, with a high gradient of tolerance to pollution, indicating contamination in the points that were found. For water quality analysis, several parameters did not meet the standards for class 2 waters, such as Escherichia coli, total phosphorus, dissolved oxygen, turbidity and pH. The studies conducted point out that the area under study suffers environmental impacts due to poor basic sanitation, contributing to the discharge of sewage directly into water bodies, causing the degradation of water in the Santo Antônio River watershed.