Acute toxicity of magnetite nanoparticles coated with oleic acid in the amphipod Hyalella curvispina

ESPERT, NURIA GUADALUPE; MORELL, MALENA; VILLANOVA, JORGELINA; MARDIROSIAN, MARIANA NOELIA; VEDELAGO, SOFÍA AYELEN; LASCANO, CECILIA INÉS; VENTURINO, ANDRÉS

Montevideo

Congreso; SETAC Latin America 15th Biennial Meeting; 2023

SETAC

The main productive activities in North Patagonia are oil and gas exploitation and fruit culture. Such activities may generate pollutants that can reach natural and artificial watercourses, affecting aquatic life. Due to the high quality of regional water resources, there is an environmental preservation requirement from different social actors. In this context, the presence of organic contaminants on aquatic environments require effective solutions and there is a worldwide growing necessity of techniques that minimize their concentration. Nowadays, the development of environmental remediation technologies using nanomaterials has emerged as an interesting alternative. However, prior to their application, it is necessary to carry out an initial toxicity evaluation of these materials. Our aim was to evaluate the acute toxicity of magnetite nanoparticles coated with oleic acid (NPOA), developed and synthesized by our group for the remediation of hydrocarbons-contaminated water. This study analyzed NPOA acute effects in adult individuals of the native amphipod Hyalella curvispina. Individuals were collected from a reference site in Mari Menuco Lake, Neuquén, Argentina. The amphipods were maintained and raised under laboratory conditions. Groups of 10 adults were exposed to a range of NPOA concentrations in 250 ml of filtered and dechlorinated water, during 96 hours at constant temperature of 23 ± 1°C and 16:8 h (L:D) photoperiod. The concentrations tested were 1, 5, 10, 25, 50, and 100 mg/l. Mortality and behavioral alterations were employed as endpoints to determine toxicological parameters. Significant differences were observed at 96 hs only between control and 5 mg/l with regards to mortality. The analysis of behavioral alterations show significant differences between control and all the NPOA concentrations tested, reaching up to 58% of exposed individuals. NPOA-exposed individuals showed alterations such as changes in reaction speed, locomotor behavior and increase in ventilation frequency. Our results suggest that the lethal effects of the NPOA could vary according to their aggregation state in the medium. NPOA aggregation starts at 10 mg/l, and is more visible as concentration increases. Hence, mortality does not show a linear relationship with concentration, while behavioral alterations do. Thus, behavioral alterations become more relevant in amphipod health status than direct lethal effects driven by NPOA exposure.