The environmental impact of agricultural activity on the Reserva Biológica do Mato Grande – RS

Abstract

The Biological Reserve (REBIO) of Mato Grande is a Conservation Unit located in the municipality of Arroio Grande, in the south of Rio Grande do Sul. Its amortization zone has forty rural properties registered in the irrigation system of the State Foundation for Environmental Protection of RS (FEPAM), of which about 82%, use Roundup (original and transorb) whose active ingredient is glyphosate. The objective of this work was to analyze the environmental impact of rice growing in REBIO Mato Grande through pollutant markers in the environment and the benthic macroinvertebrate community in three points of the Arroio Moreira, as it is the one that most contributes to water volume. The indicator for the release of domestic effluents (linear sulfonated alkylbenzene – LAS) was not found in the collection stations analyzed, indicating that the impacts on aquatic fauna do not have a significant contribution from domestic activities. On the other hand, the glyphosate agricultural activity marker was found at one of the points (0.08 mg.L-1) being above the maximum allowed value (0.065 mg.L-1) by CONAMA Resolution No. 357/2005. There was a decrease in all biological metrics analyzed (Wealth, Shannon-Wiener diversity index and Abundance) and changes in abiotic parameters such as dissolved oxygen, conductivity, turbidity, and total dissolved solids, allowing us to conclude that rice farming contributes significantly to the disturbance of the analyzed environment.