Contamination and oxidative stress biomarkers in estuarine fish following a mine tailing disaster

Abstract

Background The Rio Doce estuary, in Brazil, was impacted by the deposition of iron mine tailings, caused by the collapse of a dam in 2015. Based on published baseline datasets, the estuary has been experiencing chronic trace metal contamination effects since 2017, with potential bioaccumulation in fishes and human health risks. As metal and metalloid concentrations in aquatic ecosystems pose severe threats to the aquatic biota, we hypothesized that the trace metals in estuarine sediments nearly two years after the disaster would lead to bioaccumulation in demersal fishes and result in the biosynthesis of metal-responsive proteins. Methods We measured As, Cd, Cr, Cu, Fe, Mn, Pb, Se and Zn concentrations in sediment samples in August 2017 and compared to published baseline levels. Also, trace metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Se and Zn) and protein (metallothionein and reduced glutathione) concentrations were quantified in the liver and muscle tissues of five fish species (Cathorops spixii, Genidens genidens, Eugerres brasilianus, Diapterus rhombeus and Mugil sp.) from the estuary, commonly used as food sources by local populations. Results Our results revealed high trace metal concentrations in estuarine sediments, when compared to published baseline values for the same estuary. The demersal fish species C. spixii and G. genidens had the highest concentrations of As, Cr, Mn, Hg, and Se in both, hepatic and muscle, tissues. Trace metal bioaccumulation in fish was correlated with the biosynthesis of metallothionein and reduced glutathione in both, liver and muscle, tissues, suggesting active physiological responses to contamination sources. The trace metal concentrations determined in fish tissues were also present in the estuarine sediments at the time of this study. Some elements had concentrations above the maximum permissible limits for human consumption in fish muscles (e.g., As, Cr, Mn, Se and Zn), suggesting potential human health risks that require further studies. Our study supports the high biogeochemical mobility of toxic elements between sediments and the bottom-dwelling biota in estuarine ecosystems.

Cadmium, Lead, Copper, Zinc, and Iron Concentration Patterns in Three Marine Fish Species from Two Different Mining Sites inside the Gulf of California, Mexico

“…However, the relationship between trace metals concentration in fish tissue and mining activities has not been fully addressed in the scientific literature, especially regarding phosphorite mining and the comparisons between sites exploiting different minerals. The available reports suggest variable bioaccumulation patterns among fish sharing the same location [ 7 , 8 ]. In a site polluted by phosphorite mining on the coast of Togo, the highest metal concentration observed in fish were cadmium (1.68 µg g −1 ) in Chloroscombrus chrysurus , lead (8.49µg g −1 ) in Galeoides decadactylus , and zinc and iron (1.48 µg g −1 and 2.99 µg g −1 , respectively) in Ilisha africana [ 8 ].…”

“…In a site polluted by phosphorite mining on the coast of Togo, the highest metal concentration observed in fish were cadmium (1.68 µg g −1 ) in Chloroscombrus chrysurus , lead (8.49µg g −1 ) in Galeoides decadactylus , and zinc and iron (1.48 µg g −1 and 2.99 µg g −1 , respectively) in Ilisha africana [ 8 ]. In another study, the grass carp Ctenopharyngodon idellus thought to be affected by copper mining in the district of Purple Mountain, China, for over 30 years, recorded concentrations (dry weight) of up to 8.5 ± 0.75 µg g −1 of copper, 27.7 ± 2.7 µg g −1 of zinc, and 0.705 ± 0.155 µg g −1 of lead, and no detectable concentrations of cadmium [ 7 ]. In fish from a site affected by the collapse of an iron mining dam in the Rio Doce, Brazil, the highest concentration (dry weight) of lead and copper (8.55 and 1.15 µg g −1 , respectively) were recorded in Eugerres brasilianus , and the highest concentration of zinc (477 µg g −1 ) was recorded in Genidens genidens .…”

One Decade of Environmental Disasters in Brazil: The Action of Veterinary Rescue Teams

“…In the case of the Mariana disaster, even other states had been affected, for example, the State of Espírito Santo, where the mouth of the river Doce, sourced in Minas Gerais, is located. Some of these impacts were observed in estuarine fish, through tissue bioaccumulation and oxidative stress defenses observed in response to the contamination of the river Doce (11).…”

Manganese: The overlooked contaminant in the world largest mine tailings dam collapse

“…The tailings were transported approximately 600 km downstream and reached the estuary and the ocean 16 d after the dam collapse (de Gomes et al, 2017 ; Queiroz et al, 2021 ). The disaster represents one of the largest failures of a tailings dam ever recorded and the largest environmental disaster in Brazil’s mining history ( Carmo et al, 2017 ), also killing 19 people and causing extensive ecological (e.g., soil and water pollution; Bernardino et al, 2019 ; Gabriel et al, 2020b ; Queiroz et al, 2018 ), economic, social and cultural damages ( Fernandes et al, 2016 ).…”