An Overlooked Potential Health Risk of Neonicotinoid: The Dietary Exposure from Rice in China

Neonicotinoids (neonics) are widely used seed treatment agents in agriculture due to their systemic property. They have been frequently detected in various fruits and vegetables, but the health risks of neonics resulting from rice consumption, the staple food for one-third of the world's population remain inadequately characterized. In this study, we analyzed 348 rice samples from 14 provinces covered at least 80% of rice production regions in China. The integrated concentrations of seven neonics in these samples were determined using a relative potency factor method. The geographical distribution and correlation of these neonics in rice were analyzed. Furthermore, we estimated the risk ranking for individual neonics and chronic exposure risk for rice consumptions. Results showed that at least one neonic was detected in 93.3% rice samples with the IMIRPF levels ranging from 44.2 to 236.6 mu g/kg across different provinces. The highest concentration of neonics was identified in rice from northeast China region. Simultaneously, a substantial correlation was observed among neonics. Among these, thiamethoxam was identified as the neonic posing the greatest risk to population health. Although children are more vulnerable to neonics exposure than adults, the estimated daily intake (EDI) for both groups stayed below the reference dose (RfD) of 0.057 mg/kg/day. This study highlights that rice consumption may be an overlooked pathway for neonic dietary intake compared to vegetables and fruits, emphasizing the need for greater attention to staple foods.