Triple-mixture of Zn, Mn, and Fe increases bioaccumulation and causes oxidative stress in freshwater neotropical fish.

Abstract

Metal bioaccumulation and oxidative stress biomarkers were determined in Prochilodus lineatus to understand the effects of short-term exposure to a triple-mixture of Zn, Mn, and Fe. Three independent tests were carried out, in which fish were exposed to 3 concentrations of Zn (0.18, 1.0, and 5.0 mg L-1 ), Mn (0.1, 0.5, and 5.0 mg L-1 ), and in the mix test to Fe (5.0 mg L-1 ) and a mixture of Zn (1.0 mg L-1 ) + Mn (0.5 mg L-1 ), with and without Fe. After exposure for 96 h, tissues were removed for metal bioaccumulation analysis and oxidative stress biomarkers were determined in liver, along with DNA damage in blood cells. Our results revealed that Zn and Mn were bioaccumulated in fish tissues after exposure to 5.0 mg L-1 , whereas Fe only bioaccumulated in muscle and gills after mixture exposure. Results indicated that 1 metal interfered with the other's bioaccumulation. In P. lineatus, 5 mg L-1 of both Mn and Fe were toxic, because damage was observed (lipid peroxidation [LPO] in liver and DNA damage in blood cells), whereas Zn induced liver responses (metallothionein [MT] and reduced glutathione [GSH] increases) to prevent damage. In terms of bioaccumulation and alterations of oxidative stress biomarkers, we showed that Zn, Mn, and Fe triple-mixture enhances individual metal toxicity in Neotropical fish P. lineatus. Environ Toxicol Chem 2018;37:1749-1756. © 2018 SETAC.