Mengieng commenced her career as an Environmental Scientist, focusing on the impacts of climate change on drinking water quality along Cambodia's Mekong and Tonle Sap rivers. As she transitioned into Geography, her research broadened to encompass global health challenges, particularly emphasizing the health impacts of climate change and adaptation strategies in coastal Cambodia. Her interdisciplinary expertise extends to digital health, communicable diseases (HIV/AIDS and tuberculosis), maternal and child health, and non-communicable diseases. At SDGHI, she is a Research Fellow working with the Planetary Health Team.