A systematic review of non-dietary human risks of neonicotinoids in China: environmental concentrations, human exposure and risk assessment.

Neonicotinoids (NEOs) are extensively used in China and become a national concern due to their prevalence in the environment and human bodies. However, the non-dietary exposure to NEOs and their health risks to Chinese population remained unclear. This review compiled a comprehensive national dataset, comprising 39 studies on environmental concentrations across surface water, soil and indoor dust, as well as 20 studies on human internal exposure. Our analysis revealed that six NEOs, namely imidacloprid, acetamiprid, thiacloprid, dinotefuran, thiamethoxam and clothianidin, were widely distributed across all environmental media with distinct regional characteristics. Imidacloprid and acetamiprid exhibited relatively higher concentrations, while thiacloprid showed the lowest concentrations. Subsequently, people's non-dietary exposure to NEOs based on NEO environmental concentrations was investigated, considering routes including oral intake, dermal contact and inhalation. Surface water was the primary source of non-dietary exposure, accounting for 65.1 %-98.2 %, followed by indoor dust and soil. Regionally, Hainan, Zhejiang, Hebei exhibited relatively high non-dietary chronic daily intake values. Additionally, NEO concentrations in human blood and urine were analyzed across different populations, and total daily intakes of NEOs were estimated accordingly. Non-dietary exposure to NEOs contributed only 0.2 %-7.6 % of the total NEO exposure, with children experiencing higher proportions. Although the carcinogenic and non-carcinogenic risks from non-dietary exposure to NEOs were relatively low, children faced significantly higher risks. Future studies should target on NEO management and control in aquatic environments, the combined health effects of NEOs and other contaminants, and strategies for protecting children from NEO exposure.