Many studies have proven that microplastics are transported from the terrestrial ecosystem to the marine ecosystem. Furthermore, it has been established that a significant quantity is added to the marine ecosystem through river transport and atmospheric deposition. Though several methods exist to estimate the concentration of microplastics in the marine ecosystem, it is very difficult to precisely quantify the pollutants and determine the amount transported from the land to the ocean. The data on the extent of microplastic pollution are influenced by the sampling methods and the time of sampling. An examination of the literature reveals that only limited studies have been conducted to examine the interaction of microplastics and their additives with the marine organisms. Hence, more such studies are warranted to shed light on these interactions. Few modeling studies have been conducted to estimate the future addition of plastics to the marine ecosystem. To obtain better output, appropriate models that consider the current scenario need to be developed. Models help us to understand the sources, transport, sinks, and risks of microplastic pollution. This will enable us to develop appropriate strategies and, measures to reduce plastic littering in the environment, thus marine plastic pollution is minimized in the future.

The estuarine ecosystem is under threat due to the addition of different anthropogenic pollutants. Among the various pollutants, microplastics(MPs), and antibiotics play a significant role in affecting estuarine organisms and human health by transport through the food chain. In the estuaries, microorganisms, including pathogens, colonise microplastics by the development of biofilms. Estuaries have long been home to MPs, served as novel hubs for the transmission of Antibiotic Resistance Genes (ARGs). As a result of their continual interactions with a variety of aquatic creatures, MP-associated bacterial communities will eventually present a transfer opportunity to organisms that consume MPs. To comprehend the presence of microplastics and ARGs in the estuaries, a thorough review is necessary. This review discusses the various sources of MPs and antibiotic pollution, as well as the transport of ARGs via biofilm formed on MPs. Furthermore, the factors affecting biofilm formation in estuaries are reviewed. In addition, the transport of ARGs by microbial populations within biofilm is discussed. The ARGs are transported into the food chain, which will be a threat to human health. Hence, the occurrence of antibiotic-resistant genes in fish is discussed.