The implications and health effects of microplastics (MPs) ingestion are still unclear, yet researchers and organizations around the world are increasingly examining the levels of microplastics and nanoplastics in the environment. This study investigated the presence and the quantity of microplastics in bottled and tap water from five regions in Saudi Arabia and estimated the dietary intake of microplastics. Thirty samples of drinking water were collected from the retail markets in Saudi Arabia. The samples included plastic bottled drinking water, 2 glass bottles, and 2 samples of tap water to represent ground water and desalinated seawater. Sample preparation in the laboratory involved a vacuum-assisted filtration with an inorganic filter membrane (0.2-µm pore size). Identification and classification of microplastics particles using Fourier-transform infrared microspectroscopy (FTIR microspectroscopy). The particle size range screened for in this study was 25-500 μm. Microplastics were identified in 17 out of 30 samples. The average of the detected microplastic particles was 1.9 pcs/L (lower bound estimate, LB) and 4.7 pcs/L (upper bound estimate, UB), respectively. The most frequently identified plastic type was polyethylene (PE), followed by polystyrene (PS), and polyethylene terephthalate (PET). Given an average recommended water intake of 3.7 and 2.7 L per day for men and women, respectively, the corresponding daily exposure to microplastics would result in 0.1-0.2 pcs/kg bw. The estimate for high water consumers increases to a daily exposure of 1.7-1.9 pcs/kg bw based on the recommended intake for water in hot weather by the WHO. From these results, we conclude that the level of dietary intake of microplastics from drinking water in Saudi Arabia is low, and according to current state of knowledge, microplastics from drinking water do not pose any concern to the consumers in Saudi Arabia.
Keywords: Bottled water; Dietary intake; Human health risks; Microplastics; Plastic pollution.