Occurrence and trophodynamics of rare earth elements and co-existing heavy metals in a terrestrial food web from REE mining areas in South China

Li, W.; Qiu, H.; Gestel, C.A.M. van; Peijnenburg, W.J.G.M.; He, E.

doi:doi:10.1016/j.jhazmat.2026.141735

High concentrations of trace metals, including rare earth elements (REEs) and co-existing heavy metals (HMs), have been widely observed in soils surrounding mining activities. However, there remains a paucity of field evidence regarding their trophic transfer risks. Here, we collected a diverse array of soil food web components, comprising 60 species of soil organisms from 16 orders, to quantitatively assess the trophodynamic patterns of trace metals in contaminated agricultural soils near the REEs mining areas in southern China. A simplified soil food web consisting of three trophic levels (TLs) was constructed using stable nitrogen isotopes. Organisms at the second TL exhibited the highest concentrations of REEs and non-essential metals (As, Pb, and Cr), while those at the third TL showed the highest concentrations of essential metal Cu. Notably, the biomagnification potential of REEs was predominantly observed between the first and second TLs, with corresponding biomagnification...Show moreHigh concentrations of trace metals, including rare earth elements (REEs) and co-existing heavy metals (HMs), have been widely observed in soils surrounding mining activities. However, there remains a paucity of field evidence regarding their trophic transfer risks. Here, we collected a diverse array of soil food web components, comprising 60 species of soil organisms from 16 orders, to quantitatively assess the trophodynamic patterns of trace metals in contaminated agricultural soils near the REEs mining areas in southern China. A simplified soil food web consisting of three trophic levels (TLs) was constructed using stable nitrogen isotopes. Organisms at the second TL exhibited the highest concentrations of REEs and non-essential metals (As, Pb, and Cr), while those at the third TL showed the highest concentrations of essential metal Cu. Notably, the biomagnification potential of REEs was predominantly observed between the first and second TLs, with corresponding biomagnification factors (BMFs) exceeding 1 for these transitions. Similarly, non-essential metals, including As, Pb, and Cr, exhibited biomagnification from the first to second TL but displayed biodilution when transferred from the second to third TL. In contrast, Cu and Cd showed a consistent biomagnification trend, with their BMFs increasing progressively across ascending TLs. Additionally, REEs with higher atomic numbers demonstrated greater BMFs along terrestrial food chains, indicating an enhanced transfer potential for heavy REEs compared to light REEs. This observation was supported by variations in REE profiles across different TLs. Overall, our study offers field-based evidence and novel insights into the trophodynamics of trace metals within terrestrial food webs, highlighting the potential ecosystem risks in agricultural soils surrounding REE mining areas in southern China.Show less

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Occurrence and trophodynamics of rare earth elements and co-existing heavy metals in a terrestrial food web from REE mining areas in South China