Anthropogenic Rare Earth Elements: Gadolinium in a Small Catchment in Guizhou Province, Southwest China

Abstract

Rare earth elements (REEs), known as “industrial vitamins”, are widely used in medical treatment, industry, agriculture, etc. However, with the increasing demand for REEs, excess REEs, such as gadolinium (Gd), are considered micropollutants in the environment. In this paper, the distributions of dissolved REEs were analyzed in three small streams, in order to determine the extent and occurrence of Gd anomalies. The shale-normalized REE patterns in the three streams were less smooth with heavy REEs higher than light REEs, for a weak reaction of the heavy REE complexes. A negative Ce (cerium) anomaly and positive samarium (Sm) and europium (Eu) anomalies were observed in the three streams and the negative Ce anomaly was affected by the pH of the alkaline rivers. However, a positive Gd anomaly was found in only a typical urban small stream, Jinzhong. With a population of approximately 60,000, Jinzhong runs by a hospital and through wastewater treatment plants (WWTPs). The concentrations of Gd in Jinzhong ranged from 1.54 to 86.65 ng/L with high anthropogenic Gd proportions (63.64%–98.07%). Anthropogenic Gd showed significant seasonal variations and distinct spatial disparities from upstream to downstream, and it was associated with certain ions such as Cl−. Anthropogenic Gd could be attributed to gadopentetic acid (Gd-DTPA), which is used in magnetic resonance imaging (MRI) in hospitals. This type of Gd was shown to be correlated with municipal wastewater. Due to the high stability and low particulate reactivity in water, anthropogenic Gd has great potential to serve as a tracer to prove the presence of medical wastewater.

Multivariate statistical evaluation of dissolved heavy metals and a water quality assessment in the Lake Aha watershed, Southwest China

“…The lowest pH value in the YR exhibited an influence of acid mine drainage. The JR was the most typical urban tributary impacted by human activities in our study, and the Jinyang Wastewater Treatment Plant with limited capacity and damaged sewer networks provided an amount of pollutant input (Huang et al, 2009;Song et al, 2011;Zhang et al, 2019). The peak value in BR-14 (a groundwater well) could attribute to the contamination of domestic sewage through karst conduits.…”

“…Among three tributaries, Ba, V and Sb show higher concentrations in BR and JR than YR. Previous investigation and the scene observation found that BR and JR are influenced by human activities more than YR, with a higher percentage of residential and commercial land (Huang et al, 2009;Song et al, 2011; Zhang et al, 2019). Considering that Ba, V and Sb are widely used in industrial and medical (Filella, Belzile & Chen, 2002;Hope, 2008;Kravchenko et al, 2014;Wilson et al, 2010), these heavy metals could be attributed to anthropogenic sources.…”

Distribution, water quality, and health risk assessment of trace elements in three streams during the wet season, Guiyang, Southwest China

“…The study area is shown in Figure 1, including Baiyan Stream (BY), Jinzhong Stream (JZ), and Youyu Stream (YY) at Lake Aha Catchment (26 34 0 N, 106 43 0 E; Han et al, 2019;Zhang et al, 2019). The continental climate of the study area is subtropical humid, monsoon climate, which is characterized by significant summer rainfall.…”

Lifecycle of Gadolinium‐Based Contrast Agents

“…Based on the protocol outlined by Bau and Duski 20 using inductively coupled plasma mass spectrometry (ICP‐MS), groups studying densely populated and industrialized areas in Australia, 22,23 the USA, 24,25 Czech, 26 Sweden, 20 South Korea, 27 Germany, 28,29 France, 30,31 England, 29 Japan, 32,33 Brazil, 34 China, 35 Turkey, 36 and West Africa 37 have shown Gd anomalies in their rivers, lakes, and oceans. Groups 20,23,31,38–43 have compared samples from waters upstream and downstream of WWTPs and confirmed that Gd anomalies originate in WWTP effluents and are therefore of anthropogenic origin.…”

“…Although Gd is used in many industries 24,27 as well as agriculturally, 35 anomalies are most likely the result of GBCAs excreted from patients receiving contrast‐enhanced MRI studies 20,26,43 . This is corroborated by the weekly cycle of [Gd ant ] corresponding to the application of GBCAs during the working week, 22,26,43,45,46 measured [Gd ant ] loads corresponding to the estimates of GBCA applications based on enquiries at hospitals feeding wastewater treatment plants, 26 [Gd ant ] loads corresponding to geographic locations of hospitals offering Gd‐based MRI studies, 26,31,42,43 and speciation of the GBCAs themselves 38,46,47 …”