Microplastic in the food chain – Food Safety and Environmental aspects

Abstract

Plastic is ubiquitous in our environment. It has been an incredibly useful and indispensable material in all aspects of human life and without it many advances in medicine, technology or industry would not have been possible, however, the accessibility and low cost of this material has led to global misuse. The chemical makes up of plastic has made it very easy to manufacture but unfortunately difficult to reuse or recycle and the result is that it is thrown away as litter, incinerated or disposed of in landfill. Hence the rise of “single use plastics”, of the plastic waste produced between 1950 and 2015 only 9% was recycled. There are multiple sources of plastic pollution in the environment, from direct littering, drainage systems, landfill waste, ocean dumping, blow off etc. The plastic, once in the environment begins to degrade through weathering and exposure to UV light eventually reaching very small sizes. Many animals mistake these particles for food and so the plastic enters a marine, terrestrial or freshwater food web. These microplastic particles although chemically inert have been shown to act as tiny “biosponges” for harmful chemicals found in the environment such as PBP (Penicillin binding proteins), fire retardants, microbial drugs etc. changing the nature of a plastic particle from chemically harmless to potentially toxic if ingested in large quantities. Initially it was believed that these particles would simply pass through the GI tract of animals and humans with no biological effect, however studies have shown that they are sometimes taken up and distributed throughout the circulatory system and lymphatic system and may in fact be stored in the fatty tissues of birds, plankton, mussels, fish and even humans. The result of the uptake of these toxins showed potential carcinogenic effects, liver dysfunction and endocrine disruption in many laboratory experiments. In this literature review the main focus will be on micro- and nanoplastics and how these tiny particles make their way into marine and freshwater food webs with particular attention to microplastic trophic transfer, their toxic side effects and how they may influence the human consumer in health and safety in the future.