Estimates of soil ingestion in a population of Chinese children

Introduction It is widely recognized that soil contamination in China is of serious concern (Chen et al. 2014; Larson 2014; Yang et al. 2014). Unintentional soil ingestion is a potentially [...]
Background: China's soil pollution poses serious health risks. However, data regarding the soil ingestion rate (SIR) of the Chinese population, which is critical to assessing associated health risks, are lacking. Objectives: We estimated soil ingestion of 177 Chinese children from Guangdong, Hubei, and Gansu Provinces. methods: We conducted this investigation by employing a tracer mass-balance method. We collected a duplicate of all food consumed and all feces and urine excreted on 1 d (n = 153) and over 3 consecutive d (n = 24), as well as soil samples from play areas and drinking-water samples. We analyzed concentrations of the tracer elements Al, Ba, Ce, Mn, Sc, Ti, V, and Y in these samples using ICP-AES and ICP-MS and estimated the SIR for each subject. Results: The estimated SIR data based on each tracer element were characterized by a skewed distribution, as well as higher inter-tracer and intersubject variation, with several outliers. After removing the outliers, daily SIR median (range) values in milligrams per day were Al, 27.8 (-42.0 to 257.3); Ba, 36.5 (-230.3 to 412.7); Ce, 35.3 (-21.2 to 225.8); Mn, 146.6 (- 1259.4 to 1827.7); Sc, 54.8 (-4.5 to 292.0); Ti, 36.7 (- 233.7 to 687.0); V, 92.1 (10.4 to 308.0); and Y, 59.1 (- 18.4 to 283.0). Daily SIR median/95th percentile (range) values based on the best tracer method (BTM) were 51.7/216.6 (- 9.5 to 297.6) mg/d. Conclusions: Based on the BTM, recommended SIR values for the general population of Chinese children (2.5 to 12years old) are 52 mg/d for the central tendency and 217 mg/d for the upper percentile. We did not differentiate between outside soil and indoor dust. Considering the lower concentration of tracer elements in indoor dust than outside soil, actual soil and dust ingestion rates could be higher. https://doi.org/10.1289/EHP930