Spatio-temporal distribution of cadmium levels in Chinese population and its potential risk factors

Abstract

Cadmium (Cd), a ubiquitous heavy metal, exists in numerous environmental matrices and has severe adverse effects on various human organs and tissues. This research evaluates blood and urine Cd levels in the Chinese population through data mining using Monte Carlo simulation (MCS). A total of 168 scientific studies (120 on urine and 48 on blood) published between January 1980 and December 2020, reflecting a population of 109,743 individuals in China, were included in the study. The results indicate that the blood and urine Cd levels in the Chinese population exhibited a peak from 1990 to 1995 and remained stable after 1995, averaging 1.21 μg/L of blood Cd (BCd) and 0.61 μg/L of urine Cd (UCd). The spatial trend of Cd levels varied significantly. Shandong, Zhejiang, Heilongjiang, and Guangdong provinces were identified as the top provinces with high Cd levels, which were related to factors such as tobacco sales, E-waste amounts, and contaminated rice. Additionally, the study highlights that BCd concentrations are highest among preschool-aged individuals, whereas school-age and adolescent groups exhibit the lowest levels. However, no significant difference existed among the different age groups. Males showed significantly higher Cd levels than females in the general population. Moreover, exposure to smoking, drinking, and staple food preferences had an impact on Cd levels. Furthermore, this comprehensive study, using biological monitoring and data mining, provides valuable information on Cd pollution levels in the Chinese population. It presents a statistical analysis that can aid decision-makers in implementing effective measures to control potential Cd pollution and improve the health of vulnerable populations.

Keywords: Blood cadmium; Cadmium exposure; Chinese population; Monte Carlo simulation; Urine cadmium.

Fig. 1

Flow diagram of the study selection process.

Fig. 2

The temporal trend of BCd and UCd of Chinese general population was based on 105,260 simulated subjects from 148 studies.

Fig. 3

The spatial distributions of BCd of Chinese general population.

Fig. 4

The BCd levels are in different subgroups according to relevant factors. a: Age; b: Sex; c: Smoking; d: Drinking; e: Dietary preference. The numerical values depicted above the bar chart represent the sample size of each group. ***P < 0.001.

Fig. 5

The population BCd levels and environmental factors associated with Cd pollution in Cd exposed provinces. a: A graphic summary of 27 provinces. b: Correlation analysis between BCd and tobacco sales, Cd pollution waste water, Cd content in soil, Cd content in rice, and the amount of e-waste. c: The spatial distribution of BCd and tobacco sales, Cd polluted waste water, Cd content in soil, Cd content in rice, and the amount of e-waste.