Microplastics have been accumulating in the environment for nearly half a century and are found in oceans worldwide, including in the Antarctic . Despite this worldwide dissemination of plastic fragments, the global load of plastics on the open ocean surface has been estimated to be far less than might be expected, but nevertheless increasing. Thus, the potential effects of microplastics on marine ecosystems are still far from being well understood . It is believed that the virging MPs are not chemical contaminants to marine organism, but they can produce physical problems such as digestive congestion. However, they can be loaded with many substances to fit the virgin MPs to industry and consumer demand (e.g. additives, preservatives, etc.). In addition, these MPs can also adsorb contaminants present in the environment and act as vectors.
One of the most important factors affecting microplastic distribution in marine waters is the density of the materials. Materials whose specific density is less than that of marine water (∼1.02) may be located on the surface, while materials with a specific density greater than that of marine water may be sink.
Microplastics in the aquatic environment have been demonstrated to be a significant problem. The great amount of research on this topic, as well as the quantity of the results that describe the problem of MPs and their effects on fishes and aquatic life, have thrown some light on this issue. Among the effects that MPs have are stress, intestinal obstruction and the alteration of health, while further studies are in progress to ascertain the full potential risks of MPs in aquatic organisms with special attention paid to fish. A huge number of substances are added to plastics, which can bioaccumulate throughout the trophic chain. Besides the problems that MPs represent for marine life in general, the MPs could begin act as disruptors of the welfare and health of fishes, both wild and cultivated. This is clearly a growing problem not only for the environment but also for human health. For these reasons, further efforts are needed to know the exact effects that microplastics, and their constitutive and adsorbed contaminants, may have on aquatic environments.