1 Source, distribution and emerging threat of micro- and nanoplastics to marine organism and human health: Socio-economic impact and management strategies M. Mofijur 1,2 , S.F. Ahmed 3,* , S.M. Ashrafur Rahman 4 , SK. Yasir Arafat Siddiki 5 , A.B.M. Saiful Islam 6 , M. Shahabuddin 7 , Hwai Chyuan Ong 1 , T.M. Indra Mahlia 1 , F. Djavanroodi 2,8 , Pau Loke Show 9,* 1 School of Information Systems and Modelling, Faculty of Engineering and Information Technology, University of Technology, Sydney, NSW, 2007, Australia 2 Mechanical Engineering Department, Prince Mohammad Bin Fahd University, Al Khobar, 31952, Saudi Arabia 3 Science and Math Program, Asian University for Women, Chattogram 4000, Bangladesh 4 Biofuel Engine Research Facility, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia 5 Department of Chemical Engineering, Khulna University of Engineering and Technology, Khulna, 9203, Bangladesh 6 Department of Civil and Construction Engineering, College of Engineering, Imam Abdulrahman Bin Faisal University, Dammam 31451, Saudi Arabia 7 Carbon Technology Research Centre, School of Engineering, Information Technology and Physical Sciences, Federation University, 3842 Churchill, VIC, Australia 8 Mechanical Engineering Department, Imperial College, London, SW7 2AZ, UK 9 Department of Chemical and Environmental Engineering, University of Nottingham, Malaysia, 43500 Semenyih, Selangor Darul Ehsan, Malaysia *Corresponding author: showpauloke@gmail.com (Pau Loke Show); shams.f.ahmed@gmail.com (S.F. Ahmed) Abstract The nature of micro- and nanoplastics and their harmful consequences has drawn significant attention in recent years in the context of environmental protection. Therefore, this paper aims to provide an overview of the existing literature related to this evolving subject, focusing on the documented human health and marine environment impacts of micro- and nanoplastics and including a discussion of the economic challenges and strategies to mitigate this waste problem. The study highlights the micro- and nanoplastics distribution across various trophic levels of the food web, and in different organs in infected animals which is possible due to their reduced size and their lightweight, multi-coloured and abundant features. Consequently, micro- and nanoplastics pose significant risks to marine organisms and human health in the form of cytotoxicity, acute reactions, and undesirable immune responses. They affect several sectors including aquaculture, agriculture, fisheries, transportation, industrial sectors, power generation, tourism, and local authorities causing considerable economic losses. This can be minimised by identifying key sources of environmental plastic contamination and educating the public, thus reducing the transfer of micro- and nanoplastics into the environment. Furthermore, the exploitation of the potential of microorganisms, particularly those from marine origins that can