Levels of rare earth elements, heavy metals and uranium in a population living in Baiyun Obo, Inner Mongolia, China: A pilot study

Abstract

h i g h l i g h t sRepresenting the first human biomonitoring study carried out in Baiyun Obo deposit. Levels of urinary REE, HMs and U were obtained in a population living in Baiyun Obo. HMs and U in the population increased concomitantly with increasing REE levels. Individual factors such as gender and age contributing to the inter-individual variation. Males and people in the young group were more sensitive to REE, HMs and U exposure. t r a c tThe Baiyun Obo deposit is the world's largest rare earth elements (REE) deposit. We aimed to investigate levels of REE, heavy metals (HMs) and uranium (U) based on morning urine samples in a population in Baiyun Obo and to assess the possible influence of rare earth mining processes on human exposure. In the mining area, elevated levels were found for the sum of the concentrations of light REE (LREE) and heavy REE (HREE) with mean values at 3.453 and 1.151 lg g À1 creatinine, which were significantly higher than those in the control area. Concentrations of HMs and U in the population increased concomitantly with increasing REE levels. The results revealed that besides REE, HMs and U were produced with REE exploitation. Gender, age, educational level, alcohol and smoking habit were major factors contributing to inter-individual variation. Males were more exposed to these metals than females. Concentrations in people in the senior age group and those with only primary education were low. Drinking and smoking were associated with the levels of LREE, Cr, Cu, Cd and Pb in morning urine. Hence this study provides basic and useful information when addressing public and environmental health challenges in the areas where REE are mined and processed.

Rare-earth elements in human colostrum milk

“…Recent human biomonitoring studies have reported that urine and hair contain detectable levels of all REEs (Wei et al 2013;Hao et al 2015;Wang et al 2017), and one could expect a similar result for breast milk. The mammary gland is, however, known to regulate concentrations of essential elements to avoid their deficiency or excess in milk, both harmful to a newborn (Lönnerdal 2007), and that such concentrations are not associated with maternal status (Domellöf et al 2004).…”

“…Although the significantly increased concentration of Nd observed for currently smoking women is worth further attention, one should bear in mind the small group size (n = 3). A human biomonitoring study conducted in 2010 in China did not find any association between the smoking habit and Nd levels though current and former smokers had higher concentrations of LREEs (of which Nd is one of seven representatives) in morning urine (Hao et al 2015). As evidenced experimentally, exposure to Nd can cause cytotoxicity and genetic damage through oxidative stress (Palmer et al 1987;Jha and Singh 1995;Huang et al 2011), although it is unknown whether Nd poses any threat in the concentrations found in the colostrum milk of smoking women.…”

“…Considering that important sources of REEs are emissions from vehicles (Wang et al 2001), a reasonable approach was to compare their concentrations in milk collected from mothers inhabiting urban and rural areas. The increased REEs concentrations in human have been so far associated with mining and smelting areas (Wei et al 2013;Hao et al 2015;Wang et al 2017). However, urban populations have been shown to reveal elevated levels of certain pollutants such as arsenic, mercury, platinum group elements, cadmium, and lead in blood, tissue, urinary, and hair (Iavicoli et al 2007;Rzymski et al 2015;Roca et al 2016;Rzymski et al 2016b).…”

“…The data concerning the toxicity of REEs is mostly limited to Nd, La, Ce, and Gd, and is based predominantly on animal studies and observations of occupational human exposures with no comprehensive observation on the effects of long-term exposure (Pagano et al 2015). It is however known that REEs can accumulate in humans at increased levels in certain populations at higher exposure risk, e.g., those residing in the vicinity of mining areas Wei et al 2013;Hao et al 2015;Rzymski et al 2017a). A recent study linked REE levels in hair with higher a risk of hypertension in women .…”

Atmospheric Signature and Potential Sources of Rare Earth Elements in Size-Resolved Particulate Matter in a Megacity of China

“…REEs can accumulate in the human body and be deposited in organs via ingestion of food, inhalation of ambient PM and dermal contact (Koeberl and Bayer, 1992;Hao et al, 2015). Several studies have noted that REEs follow hermetic, concentration-related trends, implying stimulatory or protective effects at low concentrations and detrimental effects at high concentrations (Zhao et al, 2008;Pagano et al, 2015).…”