MARINFORSK-Marine ressurser og miljø

Plastics and microplastics pollute the marine environment and as the field of microplastic research eveolves more data are available on their levels in the environment. On a global scale for both urban and pristine areas, it is now evident that microplastics are in the water phase, in and on sediments and interacting with biota. Microplastics are often defined as plastic particles smaller than 5 mm, and current understanding is that the smaller microplastics are the most dominant in the environment. Because of their small size, microplastics can interact with all levels of the food web from algae to large mammals. Ingestion is the most probable interaction with biota and at least 331 species are known to ingest microplastics. However, minimal data are available on the impact of microplastics on Norwegian marine biota. Therefore, the MIME project is aiming to increase the knowledge base on levels in the Norwegian biota, as well as investigating if there is any harm to marine organisms. In this project, we have thus far studied levels of microplastics in Atlantic cod (Gadus morhua) from the Norwegian coast, where a total of 3% of the fish individuals had ingested plastics. For bivalves, for example blue mussels (Mytilus edulis), there are very limited data available, and since blue mussels are important both ecological and as a food source for humans, it is important to get more knowledge on microplastic in Norwegian mussels. Therefore, we are currently studying ingestion in blue mussels, after optimizing methods to be able to do this. How ingestion might affect the biota that contain mircroplastic is still unknown. From controlled laboratory studies however, it can negatively affect organisms. For example, their energy reserves and fitness have been found to be impacted, since they do not efficiently take up nutrition. We have also conducted such controlled laboratory studies on blue mussels with plastic particles from toothpaste. The mussels did ingest these particles, and that they took up more particles that had been in the environment than ?clean? particles. This is probably due to growth of microorganisms on the plastic particles. In our study, we also found alterations in their tissue following uptake of microplastics. Effects seen from ours and other microplastic laboratory exposures, are hard to extrapolate to the environment. The marine environment is much more complex than a laboratory scale study and it is thereby hard to establish a causal relationship. Despite the uncertainties on negative effects from microplastic uptake, it is a consensus that microplastics are unwanted in the environment and that the precautionary principle should be used.

Over the past decade there has been a realisation that plastic in the form of very small particles, so-called ?microplastics?, pollutes much of the marine environment. These microplastics occur due to the release of manufactured microplastics in various p roducts and the breakdown of larger plastic litter. It is known that ingested microscopic plastic translocates to the circulatory system in blue mussels, which retain the plastics for over 48 days. What is unclear is whether the presence of microplastic a t both the micro- and nano-scale is having an impact on marine organisms. This project will seek to establish whether the presence of micro- and nano-sized plastic particles in the marine environment impact on marine organisms. This will be evaluated for both the particles themselves and the additives and adhered chemicals that may be associated with them. There will be special focus placed on establishing where microplastics enter the food-chain and whether they will be translocated. Experiments will be performed that are pertinent to both Arctic and bordeal species. Additives can account for up 20% of a plastic and their presence and the environmental factors that control their release and persistence will be evaluated. An important factor regarding the presence of microplastics in the environment is that they will interact with other contaminants and a kep part of this project will be to evaluate how the environment affects the interactions of microplastics with known hazardous substances and whether m icroplastic vectors may pose an as yet unrecognised risk to seafood safety by affecting hazardous substance uptake.