Analysis of Tebuthiuron Environmental Impact Through the Use of Winogradsky Columns

Abstract

Tebuthiuron is a soluble and leachable herbicide that is highly used in crop fields in Brazil. Therefore, the aim of the present study was the analysis of the impact of tebuthiuron in the water. Through Winogradsky columns to replicate an aquatic environment contaminated with the xenobiotic compound, it was evaluated the toxicity of tebuthiuron in the microorganisms (bacteria, fungi, and algae). Phytotoxicity tests with Lactuca sativa seed were also done after eight weeks after the start of the assays with the columns. It was also carried out physicochemical characterization of the water from the columns throughout the experiments. The results proved that the herbicide did not affect the pH and the conductivity of the water. The microbiological assays showed that tebuthiuron affect directly the development and the number of cultivated bacteria, significantly reducing the number of CFU mL−1 and accelerating the death phase of the bacteria cells. Chlorophyll A results also confirmed the negative effect of the tebuthiuron in algae organisms, and the treatment with the highest concentration of tebuthiuron did not reach chlorophyll A values of the control even at the end of the eighth weeks of the tests. Even though diluted in water, tebuthiuron still showed to be harmful to L. sativa seeds, significantly inhibiting germination and root elongation when compared to the control. Therefore, it was possible to conclude that tebuthiuron affects the river and lake environments, eliminating algae, bacteria, and plant organisms present in this environment.