Dietary exposure to neonicotinoids of the Hong Kong population through a total diet study

Neonicotinoids (neonics) are a class of insecticides with a similar structure to nicotine and have been used in agriculture since the late 1990s, gradually replacing organophosphorus pesticides and carbamates as the most widely used insecticides. Dietary exposure assessment of the Hong Kong adult and younger populations to neonics was included in the second Hong Kong Total Diet Study (TDS). A total of 187 commonly consumed food items were collected and prepared "as consumed". A total of 374 composite food samples were analysed for neonics by a QuEChERS method and combined liquid chromatography-tandem mass spectrometry (LC-MS/MS). Dietary exposure to 11 neonics was estimated based on the analytical results and the food consumption data of the local residents. The results showed that 183 out of 374 composite TDS samples tested positive for neonics, a detection rate of 49%. The five most commonly detected residues of neonics were imidacloprid (37%), clothianidin (37%), thiamethoxam (36%), acetamiprid (26%) and dinotefuran (21%). Neonics were mainly found in the four plant-based food groups, (i.e. "cereals and their products", "vegetables and their products", "legumes, nuts and seeds and their products" and "fruits"). The upper-bound exposure estimates for both average and high consumers (90th percentile) of adult and younger populations were all <1% of their respective acceptable daily intake (ADI) values. Hence, the findings of this study indicate dietary exposure to these 11 neonics is unlikely to pose significant health risks for the average and high consumer of adults and younger population in Hong Kong.