[Occurrence Characteristics and Associated Factors of Alzheimer's Disease Drugs in Wastewater in China]

Alzheimer's disease (AD) is a common neurodegenerative disease. The usage of its therapeutic drugs is increasing with the intensification of population aging. These drugs cannot be completely metabolized in the human body and enter wastewater systems in the form of the originals or metabolites. In-depth investigation of the occurrence characteristics of these drugs in wastewater is of great significance for effective control and management. The concentrations and associated factors of four main AD drugs (donepezil, rivastigmine, galantamine, and memantine) and their metabolites in the influent of 210 wastewater treatment plants across 31 Chinese provinces were analyzed. The results indicated that detection rates of the above drugs in wastewater were high, with concentrations ranging from 7.47-21.60 ng·L^-1. Among them, the concentration of donepezil was significantly higher in East China and the Northwest and Northeast regions than that in Central China; the concentrations of rivastigmine and galantamine in Southwest China were significantly higher than those in East China; and the concentrations of memantine in Northwest and North China were significantly higher than those in East China. The above results indicated that the occurrence of these drugs showed a significant regional difference. Further, the AD drugs and metabolites with detection rates above 90% and excretion rates exceeding 20% (donepezil, rivastigmine metabolite, galantamine metabolite, and memantine) were chosen as biomarkers to evaluate AD prevalence. The prevalence of AD in different regions was estimated by wastewater-based epidemiology method, and the results were highly consistent with official statistical data. These results showed that the concentrations of AD drugs in wastewater influent were closely related to the AD prevalence. Additionally, correlation analysis also found that socioeconomic factors (such as stress, aging population, level of economic development, and health care services) had a significant positive correlation with the AD prevalence, indicating that socioeconomic factors may influence the occurrence of AD drugs in wastewater by affecting the AD prevalence. These results provide a scientific basis for further understanding of the characteristics of AD drugs in wastewater treatment plants and the development of corresponding control measures.