Concentration of rare earth elements in Escravos River bottom sediments and associated ecological risk on aquatic organisms

Abstract

Rare earth elements concentration in environmental media is currently attracting global attention due to its toxic nature when accumulated above threshold levels. This research aims to provide updated information on the concentration levels, sources, and distribution patterns of rare earth elements in the Escravos River Channel, located in the Niger Delta region of Nigeria. Bottom sediment samples were collected from nine stations along a 28.5 km stretch of the Escravos River Channel. The samples were air-dried, prepared, and analyzed using an Inductively Coupled Plasma Mass Spectrometer. The results show that Lanthanum had the highest concentration, ranging from 46.28 to 113.14 mg/kg. In contrast, Terbium and Holmium had concentrations at or below the threshold value of 1 mg/kg. Average concentrations were ≤ 5 mg/kg for Gadolinium, ≤ 3 mg/ kg for Dysprosium, and ≥ 1 mg/kg for Europium. Geospatial maps revealed that REE concentrations in the Escravos River bottom sediments were predominantly distributed according to source, with anthropogenic inputs being the primary con tributor. Cluster analysis and correlation matrix analysis of the rare earth elements indicated a strong positive correlation (r = 0.999, p < 0.05) among the elements. Overall, the quality of Escravos River bottom sediments is poor, raising urgent environmental concerns due to the bioaccumulative nature of toxic metals like rare earth elements and their potential harm to biota through the food chain. Keywords Blue economy · Economic minerals · Gbaramatu · High-tech mineral · Marine science · Toxicology