-Abstract-

Following a request from the German Federal Institute for Risk Assessment (BfR), the EFSA Panel for Contaminants in the Food Chain was asked to deliver a statement on the presence of microplastics and nanoplastics in food, with particular focus on seafood. Primary microplastics are plastics originally manufactured to be that size, while secondary microplastics originate from fragmentation. Nanoplastics can originate from engineered material or can be produced during fragmentation of microplastic debris. Microplastics range from 0.1 to 5,000 μm and nanoplastics from approximately 1 to 100 nm (0.001?0.1 μm). There is no legislation for microplastics and nanoplastics as contaminants in food. Methods are available for identification and quantification of microplastics in food, including seafood. Occurrence data are limited. In contrast to microplastics no methods or occurrence data in food are available for nanoplastics. Microplastics can contain on average 4% of additives and the plastics can adsorb contaminants. Both additives and contaminants can be of organic as well of inorganic nature. Based on a conservative estimate the presence of microplastics in seafood would have a small effect on the overall exposure to additives or contaminants. Toxicity and toxicokinetic data are lacking for both microplastics and nanoplastics for a human risk assessment. It is recommended that analytical methods should be further developed for microplastics and developed for nanoplastics and standardised, in order to assess their presence, identity and to quantify their amount in food. Furthermore, quality assurance should be in place and demonstrated. For microplastics and nanoplastics, occurrence data in food, including effects of food processing, in particular, for the smaller sized particles (< 150 μm) should be generated. Research on the toxicokinetics and toxicity, including studies on local effects in the gastrointestinal (GI) tract, are needed as is research on the degradation of microplastics and potential formation of nanoplastics in the human GI tract.

-Summary-

Following a request from the German Federal Institute for Risk Assessment (BfR), the EFSA Panel for Contaminants in the Food Chain (CONTAM Panel) was asked to deliver a statement on the presence of microplastics and nanoplastics in food, with particular focus on seafood.

With regard to additives and chemical contaminants, this statement includes information up to the possible transfer of these substances into edible tissues and an estimation of the human exposure.

Although there is no legislation for microplastics and nanoplastics as contaminants in food, there are a broad range of European Union (EU) policies and legislation with regard to marine litter, covering sources and impacts and a number of EU initiatives, relevant to marine litter, including microplastics.

Microplastics

There is no internationally recognised definition of microplastics. For this statement, they are defined as a heterogeneous mixture of differently shaped materials referred to as fragments, fibres, spheroids, granules, pellets, flakes or beads, in the range of 0.1?5,000 μm. A distinction can be made between primary and secondary microplastics. Primary microplastics are plastics that were originally manufactured to be that size while secondary microplastics originate from fragmentation of larger items, e.g. plastic debris.

Methods for identification and quantification of microplastics in food, including seafood, have been reported in literature. However, in some of the studies, quality assurance to avoid contamination from the air and equipment is not described, and it is not always clear how a particle is identified as being a ‘plastic’. The methods described for microplastics include one or more of the following steps: (i) extraction and degradation of biogenic matter; (ii) detection and quantification (enumeration); and (iii) characterisation of the plastic. Some of the described methods for degradation of the biogenic matter have the drawback that some plastics are degraded to a certain degree. Enumeration is performed by examining the samples with the naked eye or with the aid of a microscope. In the literature, microplastics have been classified or named in several ways, including microfibres, film spherule, and fragment bead, film. Advanced techniques for the characterisation and identification of the type of plastic are by Fourier transform infrared spectrometry (FT-IR) and Raman spectrometry. Another technique to obtain structural information of the plastic is pyrolysis-gas chromatography/mass spectrometry (GC/MS). Identification is performed by comparison with standard spectra or pyrograms of plastic.

There is no available literature on the fate of microplastics during the processing of seafood. Humans will most often eat cleaned seafood, e.g. fish, where the gastrointestinal tract (GI) is not included. As most of the microplastics will be found in the GI tract, gutting will decrease the exposure compared to eating whole fish. This does not apply to shellfish and certain species of small fish.

Microplastics are likely to originate from other sources than the food itself, e.g. processing aids, water, air or being release from machinery, equipment and textiles, although there is no available literature on this issue. It is therefore possible that the amount of microplastics increases during processing. The effect of other processes, e.g. cooking and baking, on the content of plastics is not known.

Experimental evidence in marine organisms indicates that microplastics have the potential to be transferred between trophic levels. Fish meal has some use in poultry production and pig rearing, hence, microplastics may end up in non-marine foods. Limited data are available on the occurrence of microplastics in foods. Available data are from seafood species, such as fish, shrimp, and bivalves, and also in other foods such as honey, beer and table salt. In studies where the content of microplastics in seafood species has been determined, the microplastic content is given in different units, e.g. number of particles/marine organism or number of particles/g wet weight so it is not always possible to compare results. The concentration of microplastics in marine species is determined in the stomach, GI or the whole digestive tract. In fish, the average number of particles found per fish is between 1 and 7. In shrimp, an average of 0.75 particles/g is found. In bivalves, the average number of particles is 0.2?4 (median value)/g. Average content of microplastics reported for honey are 0.166 fibres/g and 0.009 fragments/g. In beer, fibres, fragments and granules have been found at the following amounts 0.025, 0.033 and 0.017 per mL, respectively. For table salts, microplastic content of between 0.007 and 0.68 particles/g have been found.

Microplastics can contain on average 4% of additives and the plastics can adsorb contaminants. Both additives and contaminants can be of organic as well of inorganic nature and they can be determined using universally accepted analytical methods. Trophic transfer of contaminants, e.g. persistent organic pollutants (POPs), has been reported and biomagnification has been shown. The main plastic additives and adsorbed contaminants for which some information is available comprise phthalates, bisphenol A, polybrominated diphenyl ethers, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Concentrations of up to 2,750 ng/g of PCB and 24,000 ng/g of PAHs have been found in microplastic deposited at beaches. Information on metals is scarce and data on other chemical contaminants are lacking.

Bivalves, such as mussels, are eaten without removal of the digestive tract, and thus represent a conservative scenario of microplastic exposure for all fish and other seafood. As an example, the exposure to microplastics was calculated after consumption of a 225 g portion of mussels. Using the highest amount of microplastics found in mussels, this would give an exposure of 900 pieces of microplastic. Assuming spherical microplastics with a diameter of 25 μm and density of 0.92 g/cm3, the exposure would be 7 μg of plastics. Based on the above estimate and considering the highest concentrations of additives or contaminants in the plastics reported and complete release from the microplastics, the portion of mussels would have a small effect on the exposure to PCBs (increase < 0.006%), PAHs (increase < 0.004%) and bisphenol A (increase < 2%).

There is a lack of information on the fate of microplastics in the GI tract. The available data on toxicokinetics only include absorption and distribution, whereas no information is available on metabolism and excretion. Only microplastics smaller than 150 μm may translocate across the gut epithelium causing systemic exposure. The absorption of these microplastics is expected to be limited (≤ 0.3%). Only the smallest fraction (size < 1.5 μm) may penetrate deeply into organs. There is a lack of knowledge about the local effects of microplastics in the GI tract, including microbiota. Toxicological data on the effects of microplastics as such are essentially lacking for human risk assessment.

For microplastics, it is recommended that analytical methods should be further developed and standardised, in order to assess their presence, identity and to quantify their amount in food. Quality assurance should be in place and demonstrated. Occurrence data in food, including effects of food processing, in particular, for the smaller sized particles (< 150 μm) should be generated in order to assess dietary exposure. Research on the toxicokinetics and toxicity, including studies on local effects in the GI tract, are needed, in particular, for the smaller sized particles. Research on the degradation of microplastics and potential formation of nanoplastics in the human GI tract are needed.

Nanoplastics

Based on the internationally recognised definition of nanomaterials, nanoplastics can be defined as a material with any external dimension in the nanoscale or having internal structure or surface structure in the nanoscale (0.001?0.1 μm).

In general, there is very little or no information with regard to nanoplastics for all the areas covered in this Statement.

Nanoplastics can be produced during fragmentation of microplastic debris and can originate from engineered material used, for example in industrial processes.

No analytical methods exist for identification and quantification of nanoplastics in food, thus data on the occurrence in foods are completely lacking. It is expected that the analytical strategy that applies to nanomaterials in general will be applicable.

There is no available literature on the fate of nanoplastics during the processing of seafood. Nanoplastics are likely to originate from other sources than the food itself, e.g. processing aids, water, air or being release from machinery, equipment and textiles, although there is no available literature on this issue. It is therefore possible that the amount of nanoplastics increases during processing. The effect of other processes, e.g. cooking and baking, on the content of plastics is not known.

There is a lack of information on the fate nanoplastics in the GI tract. The available data on toxicokinetics only include absorption and distribution, whereas no information is available on metabolism and excretion. It is not known whether ingested microplastics can be degraded to nanoplastics in the GI tract. Some engineered nanomaterials have shown toxic effects, however, toxicity data for nanoplastics are essentially lacking for human risk assessment and it is not yet possible to extrapolate data from one nanomaterial to the other. Nanoplastics can enter cells; the consequences for human health are unknown.

For nanoplastics, it is recommended that analytical methods should be developed and standardised, in order to assess their presence, identity (including shape) and to quantify their amount in food. Quality assurance should be in place and demonstrated. Occurrence data in food should be generated in order to assess dietary exposure. Research on the toxicokinetics and toxicity are needed.

http://www.efsa.europa.eu/en/efsajournal/pub/4501