The sensitive Persian Gulf region, consisting of Iran and Arab countries (Iraq, Kuwait, Saudi Arabia, Bahrain, Qatar, the United Arab Emirates, and Oman), faces with the triple challenge of inefficient waste management, arid climate conditions, and fragile aquatic ecosystems. This study aimed to systematically review the available evidence on microplastic pollution, with a special emphasis on the dynamics of transboundary transport through microdust, groundwater flows, and marine environments. Findings indicate that microplastic pollution has been widely confirmed in the region. Studies in Iran face multi-environmental challenges (soil, water, air), while studies in Arab countries focus more on the marine environment. The main common sources include wastewater, waste, and tire erosion. Strong evidence of transboundary transport was identified from three pathways: 1) by dust: prevailing northwest-southeast winds carry microplastics from the arid regions of Iraq and Saudi Arabia to Iran and the Persian Gulf; 2) by marine currents: water cycles in the Persian Gulf spread pollution from coastal sources to the entire basin; 3) by groundwater: although data are limited, shared aquifers (such as between Iran and Iraq) could be a potential transport pathway. microplastic pollution in the Persian Gulf is therefore a transboundary crisis that requires a transboundary solution. No country can stand alone against this pollution crossing its borders. Establishing a regional monitoring network, developing common standards and implementing environmental cooperation agreements is urgently needed.

Keywords