Anthropogenic Gadolinium Accumulation and Rare Earth Element Anomalies of River Water from the Middle Reach of Yangtze River Basin, China

Abstract

Anthropogenic rare earth elements (REEs), such as gadolinium (Gd), lanthanum (La), and samarium (Sm), have emerged as microcontaminants in surface waters. In this study, surface water samples were collected from the middle Yangtze River basin from the metropolitan region of central China (Wuhan). We further evaluated the REE characteristics and anthropogenic Gd contribution. The total dissolved REE concentration in the river ranged as 6.76–99.31 ng L–1, the lowest value globally. Furthermore, the Post-Archean Australian Shale-normalized REE patterns, the negative anomaly of Ce, and the positive anomaly of Sm, Eu, and Gd indicated that heavy REE enrichment occurred in the water body. The anthropogenic Gd (Gdanth) concentration in Fuhe River and Hanjiang River was higher than that in the other rivers, with the difference ascribed to wastewater treatment plant (WWTP) discharges. The total daily discharges of Hanxi WWTP (HX-W) and Sanjintan WWTP (SJT-W) effluent were 53.5 and 13.5 g Gdanth, respectively. These values equate to 31.1 and 12.7 g Gdanth d–1 for HX-W and SJT-W per million people. Therefore, the quantitative evaluation of Gdanth in natural water near large cities warrants more attention.

Geochemical and Seasonal Characteristics of Dissolved Iron Isotopes in the Mun River, Northeast Thailand

“…From upstream to downstream, the δ 56 Fe showed a downward trend as a whole. Compared with the δ 56 Fe in the wet These data are from [16,24,38,63].…”

“…Dissolved Fe in river water had different sources, mainly including rock weathering, anthropogenic sources (agriculture and industry activities) and other potential sources (groundwater and precipitation, etc.) [59,[62][63][64]. According to Han, Yang, Zeng and Zhao [40], the end-member of rock weathering had the highest Fe isotopes and a lower DFe/DAl ratio, the end-member of the anthropogenic source had a moderate Fe isotopes value (δ 56 Fe > 0) and the highest DFe/DAl ratio (anthropogenic input introduces extra Fe in river water) and the end-member of other potential sources had the lowest Fe isotopes value and a low DFe/DAl ratio (Chi River).…”

“…In summary, the chelation of organic matter with heavy Fe isotopes was one of the important sources of heavy Fe isotopes in river water in different climate zones. These data are from [16,24,38,63].…”

“…Figure 8. The relationship between Fe isotopes and DOC concentration in different climate zones.These data are from[16,24,38,63].…”

Effects of high Ca and Mg stress on plants water use efficiency in a Karst ecosystem

“…The N content was measured by a multi-element analyzer (Vario TOC Cube, Elementar, Langenselbold, Germany) ( Zeng et al, 2022 ). The samples were randomly measured again to ensure the recovery percentage from 95% to 105% ( Gao et al, 2021 ; Wang et al, 2021 ). All plant species and nutrients data were shown in Table S1 in the Supplemental File .…”