Spatial distribution and source appointment of rare earth elements in paddy soils of Jiulong River Basin, Southeast China

Abstract

Abstract Seventy-one samples of paddy soils and some potential sources (parent materials, fertilizers, coal combustion, vehicle exhaust and atmospheric dust) were collected from Jiulong River Basin. The concentrations of rare earth elements (REEs) were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to investigate the spatial distribution and the main sources of REEs. The average total concentration of REEs was 266.86\u202fmg·kg −1 , which was higher than the local soil background (198.37\u202fmg·kg −1 ), Chinese soil background (163.86\u202fmg·kg −1 ) and World s crust (153.80\u202fmg·kg −1 ). The spatial distributions of rare earth elements in paddy soils of Jiulong River Basin indicated a spatially homogeneous pattern respected to the concentrations. The concentrations of ΣLREEs and ΣHREEs and the ratio of LREE/HREE, (La/Yb) N , (La/Sm) N and (Gd/Yb) N indicated that the distribution patterns of REEs in paddy soils was LREE-enriched, whereas the LREEs showed a significant fractionation and the HREE showed no significant fractionation. Significant negative Eu anomalies and no significant Ce anomalies were observed in the soils according to the values of δCe and δEu. The results of enrichment factor indicated that all of the REEs were slightly enriched in the soils. The correlation analysis, REE distribution patterns, (La/Yb) N -∑REEs diagram and (La/Yb) N -(La/Sm) N -(Gd/Yb) N in the paddy soils and some potential sources were chosen to identify the source of REEs in soils. The results of source appointments indicated that the REEs accumulated in the paddy soils may be related to natural sources (in which Fujian granite may be the originator) and anthropogenic activities such as coal combustion and the application of chemical fertilizers.