Macroinvertebrados bentônicos como bioindicadores da qualidade da água do rio lontra em área urbana em, Salto do Lontra - PR

Abstract

In urban environments, the clearing of riparian vegetation, the inadequate disposal of liquid and solid waste, and changes in land use are the main causes of water quality degradation. Such anthropogenic actions lead to a reduction in the quantity and quality of water available for use and to the loss of habitats for fauna and flora. Pollution, in turn, can make water unfit for use, compromising animal and human consumption. In this way, we evaluated the influence of the urban area on the water quality of the Lontra River, using aquatic invertebrates as bioindicators in association with the analysis of physical and chemical variables. We carried out four sampling collections between June and October 2023 at three sampling sites, one upstream, one in the urban area, and one downstream of the urbanized area. Aquatic organisms were collected using a Surber sampler with a mesh opening of 0.3 mm and an area of 1.0 m². Concomitantly with the collection of invertebrates, we measured the physical and chemical variables: pH, water temperature (°C), dissolved oxygen (mg.L-¹). To determine the water quality, the bioindicator method was used through the index "Biological Monitoring Working Party" (BMWP). 1.103 individuals distributed in 40 taxa were collected. The value of the "BMWP" index revealed water quality from class IV (doubtful) to VI (very critical) at all sampling points. Therefore, no significant difference was found between the upstream, urban, and downstream points. The study demonstrated pollution and the dominance of tolerant groups in the sampled section. In this way, it can be seen that the analyzed section suffers from different types of influences, both urban and rural, which is responsible for the low values of the "BMWP". However, it is important to emphasize that forest environments can maintain a better balance of biotic and abiotic variables, emphasizing the maintenance of riparian forests, especially in urbanized environments and permanent preservation areas.