Metal Bioaccumulation, Antioxidant Responses and Histological Changes in Gill of Fat Snook Fish (Centropomus Parallelus) to Metallic Atmospheric Particul ate Matter

RAFAELLA MONTEIRO; IARA SOUZA; MARIANA MOROZESK; MICHELLY SOARES; CAROLINA DE ANGELIS; NATHAN VIEIRA; FABIANO BENDHACK; MAGDALENA MONFERRAN; DANIEL WUNDERLIN; MARISA FERNANDES

Montevideo

Congreso; SETAC Latin America 15th Biennial Meeting; 2023

SETAC Latin America

Metallic smoke released by steel industries is constitute by a mixture of fine and gross particles containing metals, including the emerging ones, which sedimentation contaminates soil and aquatic ecosystems and put in risk the resident biota. This study determined the metal/metalloids in the settleable particulate matter (SePM) from a metallurgical industrial area and evaluated metal bioconcentration, antioxidant responses, oxidative stress and the histopathology in the gills of fat snook fish (Centropomus paralellus) exposed to different concentrations of SePM (0.0, 0.01, 0.1 and 1.0 g/L), for 96 h. From the 27 metals (Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, Sn, Ba, La, Ce, W, Hg, Pb, Bi) analyzed, 18 were quantified in SePM and dissolved in seawater. The higher (>200 µg/g) metal concentrations in SePM were Fe>Al>Ti>Mn>Zn while metals dissolved in water were Al>Zn>Ba>Fe. The metals having higher bioconcentration in the gills were Fe>Sr>Zn>Al. The activity of superoxide dismutase (SOD) decreased in the gills of fish exposed to 0.1 g/L, catalase (CAT), glutathione peroxidase (GPx) and glutathione-Stransferase (GST) as well the level of glutathione were unchanged. The unchanged levels of lipidperoxidation indicate that the antioxidant responses were efficient to avoid oxidative stress. Organ lesion indices were higher in the gills of fish exposed to 0.01 and 1.0 g/L SePM. Pavement cell hypertrophy on lamellar epithelium increased taken from 50 to 75% of epithelium and epithelial lifting were more frequent; changes in blood circulation were characterized by blood congestion in the pillar cell system (11-25%).Hyperplasia of filament epithelium resulted in total or partial lamellar fusion. Focal necrose (irreversible lesion) was identified in fish exposed to 0.1 g/L SePM at very low frequency (< 10%). Although at sublethal levels, the SePM seawater contamination affects fish gills. Cellular/organ morphology changes reduce the animal performance facing new environmental challenges and implies in energy expenditure to restored cell structure. Financial support: FAPESP Grant 2019/08491-0, CNPq Grant 306818/2020-5, FONCYT, PICT- 2015-2819, SECyT-UNC, 411/18. Scholarship awards: R. Monteiro (CAPES, Finance code 1); FAPESP Pos-Doctoral fellowship I.C Souza (Grants 2016/025257-2) and M Morozesk (Grant 2021/02906-3)