Integrating three tools for the environmental assessment of the Pardo River, Brazil

Abstract

There is a growing need for strategic assessment of environmental conditions in river basins around the world. In spite of the considerable water resources, Brazil has been suffering from water quality decrease in recent years. Pardo River runs through Minas Gerais and São Paulo, two of the most economically important states in Brazil, and is being currently promoted as a future drinking water source. This study aimed at integrating three different tools to conduct a hydromorphological assessment focused on the spatial complexity, connectivity, and dynamism of the Pardo River, Brazil. Twelve sampling stretches were evaluated in four sampling campaigns, in dry and rainy seasons. In each stretch, permanent preservation areas (PPAs), hydromorphological integrity by rapid assessment protocol (RAP), and physicochemical parameters were qualified. The kappa coefficient was used to assess statistical agreement among monitoring tools. The PPA analysis showed that in all stretches, the vegetation was modified. RAP results revealed environmental deterioration in stretches located near human activities and less variability of substrates available for aquatic fauna and sediment deposition as well. Low values for dissolved oxygen in the river mouth were noted in the rainy season. Electrical conductivity was higher in stretches near sugarcane crops. The poor agreement (k<0.35) between the RAP and physicochemical parameters indicates that the tools generate different and complementary information, while they are not replaceable. Potential changes of the hydromorphological characteristics and variations in physicochemical indicators must be related to extensive PPA modification.

Avaliação toxicológica de ambientes aquáticos: importância da análise em sedimento

“…Além disso, sabe-se que ao longo do Rio Pardo há degradação das Áreas de Preservação Permanente (APP), o que favorece a contaminação difusa, devido ao carreamento de lixiviados em estações com altos índices de precipitação (Machado et al 2015). Cabe destacar que dentre os municípios pertencentes à Bacia Hidrográfica do Rio Pardo (UGRH 4), aproximadamente 20% não possuem nenhum tipo de tratamento de esgoto, e cerca de 10% possuem baixos índices (< 50%) de coleta de esgoto (CETESB 2017).…”

Biomonitoring of surface water toxicity related to urban and industrial wastewater release

“…Deforestation has been demonstrated to cause several changes in environment biodiversity, and influence litter accumulation in the remnant patches (MACHADO et al, 2015). Among various impacts of deforestation, there is the reduction of water infiltration into the soil and supply aquifers, increasing runoff and soil loss.…”

“…These protocols are a useful environmental management tool to compare various areas of the same hydrographic basin, characterizing them in a qualitative way (CALLISTO et al, 2002;MACHADO et al, 2015).…”

Avaliação do Índice de Estado Trófico e parâmetros de qualidade da água no reservatório da Usina Hidrelétrica de Sá Carvalho, Minas Gerais, Brasil

“…Os resultados mostraram que a carga de nitrogênio total alcançou o valor pico de 0,07mgN/L em SCLI01 na estação chuvosa, enquanto na estação seca foi de apenas 0,03mgN/L em SCLI01 e SCLI03F (Figura 3). Machado et al (2015) reforçam a interferência da pluviometria no incremento desse nutriente em função de diversos mecanismos, como a biofixação desempenhada por bactérias e cianobactérias presentes nos corpos hídricos, que incorporam o nitrogênio atmosférico em seus tecidos, contribuindo para a presença de nitrogênio orgânico nas águas; a fixação química, reação que depende da presença de luz, também acarreta a presença de amônia e nitratos nas águas, pois a chuva transporta tais substâncias, bem como o arraste das partículas contendo nitrogênio orgânico para os corpos hídricos. Figura 3.…”