In this blog post, Dr. Laís Silva talks about the latest published article from the major project she took part in during her doctorate in Brazil, which so far has 42 related scientific articles.
In a global scenario where large-scale food production is required, Brazil has the space and favorable climate to do so, a factor that has led the country to become the largest sugarcane producer in the world with a planted area of around 8 million hectares. Growing this monoculture requires the application of herbicides and insecticides to guarantee productivity. One of the points to be highlighted is that one of the insecticides used on this crop is the insecticide fipronil, banned in the European Union since 2013 for posing risks to human health.
In addition, for ethanol production, vinasse, a highly acidic residue, is generated in the distillation stage and used as a fertilizer. In this background, based on concern about the environmental impacts that large-scale agriculture can have on natural ecosystems, experiments with ecosystem models were carried out (Figure 1). The article published by Dr. Bianca Goulart mainly deals with the chemical aspects of contaminants, their dynamics, fate, and degradation. Considering the results of the group’s previously published articles, the environmental risk of contamination of the aquatic system was calculated.
The ecotoxicological studies cited in this article represent the efforts of a team that involved at least seven doctoral theses, two master’s dissertations, two post-doctoral projects, and more than eight undergraduate students. For this reason, one of the main challenges was to reconcile all the experiments with the different groups of species for simultaneous exposure (Figure 2). About the chemical analysis of the application of pesticides and vinasse, the results obtained from 11 samples taken up to 150 days after contamination showed differences in the fate of contaminants in isolated applications and mixtures.
For example, the half-life of the herbicide 2.4-D ranged from 18.2 days in the individual application to 50.2 and 9.6 days in combination with fipronil and fipronil and vinasse, respectively. The variations in half-life were related to the different turbidity levels in the treatments and the hypothesis of high microbial activity due to the high level of organic matter in the vinasse. Vinasse also caused significant changes in pH and dissolved oxygen levels. The dynamics of the pesticides in the surface water resulted in the deposition of these compounds in the sediment, a factor that influences their bioavailability and ecotoxicity.
The risk assessment conducted in the article showed a potential risk to environmental health, a result that corroborates the team’s previous articles that showed ecotoxicological effects for the different trophic levels of the aquatic chain.
Conclusion
Intensive agriculture poses a risk to the biodiversity of aquatic ecosystems, considering the potential for contamination by pesticides, fertilizers, or production waste. On the other hand, with global demand for food production and alternatives to the use of fossil fuels, solutions are needed to mitigate these risks so that we can guarantee a future that reconciles environmental preservation and economic development.
Continue reading the publication “Fate and toxicity of 2,4-D and fipronil in mesocosm systems” by Bianca V. Goulart, Beatriz C. Vizioli, Thandy J. S. Pinto, Juliane S. Freitas, Raquel A. Moreira, Laís C. M. Silva, Maria Paula C. Yoshii, Laís F. P. Lopes, Allan P. Ogura, Theodore B. Henry, Evaldo L. G. Espindola and Cassiana C. Montagner. Published in Chemosphere