Assessment of metformin, nicotine, caffeine, and methamphetamine use during Chinese public holidays.

Metformin, nicotine, caffeine, and methamphetamine are widely used in China. However, the consumption pattern of these substances among the general population during Chinese public holidays may be different. Influent wastewater samples were collected from a municipal wastewater treatment plant in Yingkou, China on public holidays (n = 6) and working days (n = 20) to examine the changes in metformin, nicotine, caffeine, and methamphetamine consumption. The consumption of metformin in the city ranged from 1.94 to 14.4 g d-1 1000 people-1, while that of nicotine, caffeine, and methamphetamine ranged from 0.46 to 2.18 g d-1 1000 people-1, 31.8-89.8 g d-1 1000 people-1, and 87.0-657 mg d-1 1000 people-1, respectively. The highest consumption of metformin, caffeine, and methamphetamine was observed during the Spring Festival. The results indicated that the consumption of these substances showed almost the same trend and was higher during the Spring Festival, which may be influenced by personal habits and traditional festival reunions. There is a correlation between the consumption of nicotine and caffeine. Moreover, there are correlations between the consumption of metformin and nicotine, caffeine, as well as methamphetamine. The information based on wastewater epidemiology and consumption behavior, suggests that drug use in the region requires more attention or monitoring during holidays.