A nationwide investigation of trace elements in rice and wheat flour in China: Levels, spatial distributions and implications for human exposure

Rises in trace element contents in rice and wheat flour, which are staple foods for almost all the Chinese population, associated with rapid economic development have raised major concerns. This study aimed to assess trace element concentrations in these foods nationwide in China and associated human exposure risks. For these purposes, nine trace elements were measured in 260 rice samples and 181 wheat flour samples with 17 and 12 widely scattered geographical origins in China, respectively. Mean concentrations (mg kg(-1)) of the trace elements declined in the following orders: Zn > Cu > Ni > Pb > As > Cr > Cd > Se > Co in rice, and Zn > Cu > Ni > Se > Pb > Cr > Cd > As > Co in wheat flour. Significant regional differences in levels of trace elements in both rice and wheat flour were detected (p < 0.05), which may be related to local economic indicators. The hazard index (HI) of trace elements in rice samples from all origins exceeded 1, mainly due to the contribution of As, suggesting a potential non-carcinogenic risk. The total carcinogenic risk (TCR) for rice and wheat flour of all origins exceeded the safe level.

Automated summary

Rises in trace element contents in rice and wheat flour in China, which are staple foods for the majority of the population, have raised concerns due to their potential health risks. This study assessed the concentrations of nine trace elements in rice and wheat flour samples from different regions in China and found significant regional differences. The results indicate that the levels of trace elements exceed safe limits, posing potential non-carcinogenic and carcinogenic risks to human health.