Sugarcane vinasse provokes acute and chronic responses and bioaccumulation of metals in benthic macroinvertebrates

Abstract

Abstract Due to increases in demand and global interest in bioenergy production, Brazil has stood out in the world production of sugarcane bioethanol. The intensification in the use of this alternative energy draws attention to the environmental impacts of sugarcane cultivation and industrial processes on ethanol production, highlighting the generation of a by-product with a high pollution potential called vinasse. When vinasse reaches watercourses, it may affect the biological communities such as the aquatic macroinvertebrates, which include species sensitive to environmental contamination. Thus, this study aimed to evaluate the ecotoxicological effects of sugarcane vinasse on tropical benthic macroinvertebrates (Allonais inaequalis, Chironomus sancticaroli, Strandesia trispinosa, and Hyalella meinerti). For this, the study was separated into three phases. In the first one, acute toxicity tests were carried out with the four species. The species A. inaequalis (average LC50 = 0.460% confidence interval - CI 0.380-0.540%) was more sensitive to vinasse than C. sancticaroli (LC50 0.721%, CI 0.565-0.878%), H. meinerti (EC50 0.781%, CI 0.637-0.925%), and S. trispinosa (EC50 1.283%, CI 1.045-1.522%). In the second phase, the consequences of chronic exposure to vinasse were assessed in the two more sensitive species. Effects in reproduction and population growth rates for A. inaequalis and on development, metamorphosis, and growth of C. sancticaroli larvae occurred. Finally, the metal residuals in the body residue after chronic exposure to the two species were determined in the third phase. Vinasse provoked decreases in body residue of the essential metals Zn and Mn and the accumulation of Cd, Pb, and Cr with risks of biomagnification throughout the food webs. Low doses of vinasse provoked lethal and sublethal effects on benthic organisms, with several cascade effects on aquatic environments, given the ecological importance of this group in aquatic and terrestrial ecosystems.