Rare earth elements as sediment contamination tracers in a coastal lagoon in the state of Rio de Janeiro, Brazil

Abstract

Background: This study aimed to evaluate the environmental quality of Padre Lagoon, an urban coastal lagoon in Southeastern Rio de Janeiro, Brazil, employing rare earth elements (REEs) as tracers. Aim: The present study aimed to quantify REEs contents from Padre Lagoon to better ascertain the antropogenic environmental impact Methods: Surface sediments and one sediment core were investigated using a mass spectrometer. 14C radiocarbon dating was performed in the sediment core. Particle size analysis were made in the sediment core and the surface sediments. The Igeo index was used to isolates anthropogenic pollution. All statistical analyses were performed using the R program. Results: Sediments varied between coarse sand at different amounts. All analyzed samples contained detectable REEs, with a higher accumulation observed at the sediment core from 60 cm depth below the surface (roughly 320 cal yr BP) and, more significantly, in the upper 10 cm depth. The geoaccumulation index determined in both in the sediment core and in the surface samples indicated the presence of anthropogenic activity in the studied area. The statistical analysis showed a integration between rare earth elements and sandy mud lithology. Conclusion: The determined elements presented Igeo values indicative of slight environmental contamination. No industrial development complex is present in the study area, indicating that the main REE source to this environment may be industries located in the city of Rio de Janeiro through intensified atmospheric transport, carrying particles over long distances, potentially leading to significant biota and human health impacts in coastal environments.

Keywords

• Rare elements
• Coastal area
• Atmospheric transport
• Environmental contamination