Spatial-temporal Distribution Patterns of Urinary Cadmium Levels in the General Population in China

Cadmium (Cd) is a heavy metal element and toxic to humans. Urinary Cd is an important indicator for assessing the exposure risk of Cd. To understand the Cd exposure of Chinese population, this study analyzed spatial and temporal distribution characteristics of urinary Cd concentrations of Chinese population by using 234 references from 1980 to 2022. The results show that the mean value of urinary Cd concentration of Chinese population was 1.30 μg·g^-1(calculated based on urine creatinine). There were significant differences in urinary Cd concentration among different age groups. The mean urinary Cd concentration in children (≤14 years old) was 0.72 μg·g^-1, lower than that in adolescents and adults (>14 years old) (1.44 μg·g^-1). The urinary Cd concentration in females (1.34 μg·g^-1) was slightly higher than that in males (1.21 μg·g^-1). The urinary Cd concentration in smokers (1.24 μg·g^-1) was slightly higher than that in non-smokers (0.97 μg·g^-1). The urinary Cd concentrations of Chinese population were significantly different in both time and space. Overall, urinary Cd concentration showed decreasing trend in the time dimension. The urinary Cd concentration of females and males increased and then decreased. And the decrease rate of urinary Cd in the non-smoking population was significantly higher than that in the smoking population. Urine Cd concentration was different among regions, with higher in the south and east regions, but lower in the north and west, and the spatial distribution characteristics were affected by time. Urine Cd concentration in Hunan and Liaoning provinces showed increasing trends with time. While Jiangsu and Guangxi showed declining trends. The results of this study emphasize that the strengthening of environmental monitoring, the implementing of soil remediation and green agriculture strategies, the enhancing of public awareness of Cd pollution and prevention in high urine Cd areas are important. This study will provide a scientific basis for the development of effective Cd pollution prevention and control measures.