Developing a policy roadmap for emerging contaminants in drinking water of Thailand

Safe access to drinking water is critical for community health outcomes; however, Thailand remains challenged by the ongoing chemical contamination of its water resources. This mixed methods study aims to develop a strategic roadmap for sustainable drinking water quality control in Thailand. First, a systematic scoping review of peer-reviewed publications was conducted to evaluate the state of chemical contamination in water resources in Thailand. Concurrently, a non-targeted analysis (NTA) of water samples taken from two representative water treatment plants in Bangkok was conducted to generate the primary data to inform the development of the roadmap. The systematic scoping review has revealed the presence of various contaminants across multiple water sources, including pesticides, per- and polyfluoroalkyl substances, metals, and other inorganic chemicals. These contaminants are frequently associated with agricultural runoff, industrial activities, and inadequate waste management. NTA further annotated hundreds of suspected compounds, with pharmaceuticals and pesticides being the most prominent classes, many of which are not currently regulated in Thailand. Although Thailand’s national regulations usually match the international standards, there are still considerable gaps in the total number of regulated chemicals, enforcement strategies, and monitoring of emerging contaminants. The proposed roadmap addresses these gaps in five integrated phases: comprehensive assessment, regulatory enhancement, infrastructure upgrades, capacity building, and long-term sustainability measures. It also emphasizes the needs for public engagement and improved waste management to improve the drinking water quality. This study lays the groundwork for evidence-based policy reform and underscores the need for a unified framework to ensure the safety of drinking water in Thailand.