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Environmental Science & Technology
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Potential health impact of environmentally
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released micro- and nanoplastics in the human
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food production chain: experiences from
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nanotoxicology
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Hans Bouwmeester*, Peter C.H. Hollman, Ruud J.B. Peters
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*Corresponding author:
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Hans Bouwmeester
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RIKILT Wageningen UR,
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P.O. Box 230, Akkermaalsbos 2, 6700 AE, Wageningen, The Netherlands
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E-mail:
[email protected] 11
phone: +31317 480282
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Fax: +31-317 417717
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Keywords: Nanoplastic, microplastic, detection methods, food, toxicology
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Abstract.
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High concentrations of plastic debris have been observed in the oceans. Much of the recent concern has
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focussed on microplastics in the marine environment. Recent studies of the size distribution of the plastic
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debris suggested that continued fragmenting of microplastics into nano-sized particles may occur. In this
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review we assess the current literature on the occurrence of environmentally released micro- and
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nanoplastics in the human food production chain and their potential health impact. The currently used
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analytical techniques introduce a great bias in the knowledge, since they are only able to detect plastic
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particles well above the nano-range. We discuss the potential use of the very sensitive analytical
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techniques that have been developed for the detection and quantification of engineered nanoparticles. We
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recognize three possible toxic effects of plastic particles: firstly due to the plastic particles themselves,
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secondly to the release of persistent organic pollutant adsorbed to the plastics, and thirdly to the leaching
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of additives of the plastics. The limited data on microplastics in foods do not predict adverse effect of
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these pollutants or additives. Potential toxic effects of microplastic particles will be confined to the gut. The
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potential human toxicity of nanoplastics is poorly studied. Based on our experiences in nanotoxicology we
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prioritized future research questions.
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TOC/Abstract art:
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INTRODUCTION
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The plastic industry expanded yearly by 8.7% from 1950 to 2012, resulting in an approximate worldwide
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production of 288 million tonnes of plastics in 2012. These high production volumes, its intense use and
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rapid disposal are leading to an accumulation of plastic debris all over our planet. High concentrations of
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plastic debris have been observed in the oceans, especially in the subtropical ocean gyres,
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rural) lakes
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beaches. The discovery of the so-called plastic soup in the middle of the Pacific and Atlantic Ocean
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generated concern that these plastics could choke and starve (through accumulation in stomachs) wildlife.
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In addition, concern was raised that the plastic debris could carry a wide variety of non-indigenous and
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potentially harmful organisms around the planet
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Much of the recent concern, however, has focussed on microplastics formed by fragmentation of this
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floating plastic debris. Microplastics are dominated by plastic particles smaller than 1 cm in diameter
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~ 20 µm diameter fibrous materials.
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pollutants
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have been reported as carriers of these organic contaminants in marine and freshwater environments.
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1
4-6
and even in distinct (arctic) regions.
3, 7, 8
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in (very
Part of the plastic debris is highly visible on
2, 3, 7, 8
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12-14
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or
These plastic particles are known to absorb persistent organic
and may contain up to 4% of their weight as additives such as plasticizers.
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Microplastics 3, 16-
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Recent studies suggest that millimetre-sized particles can be nano-fragmented to even smaller 2
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particles, the so-called nanoplastics. This poses analytical challenges as the lower size limits of the most
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frequently used sampling and detection techniques are in the low micron range.
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whether nano-sized plastics can be detected with the currently used analytical methods. If nanoplastics
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are present in the human food production chain, potential health risks should be carefully evaluated,
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similar to engineered nanoparticles.
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micro- and, if available, nano-sized plastics in the environment in relation to their potential occurrence in
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the human food production chain. In order to allow for an assessment of potential adverse effects on
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human health, current detection and characterisation methods are discussed, together with indications of
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potential toxicity of nano- as well as microplastics. Our recent experience from nanotoxicological studies
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will be applied to try to advance this field of micro- and nanoplastics. Directions for future research
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priorities by merging these separated research domains will be proposed.
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10, 20, 21
It is questionable
This review summarizes current knowledge on the presence of
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PRODUCTION, USE AND ENVIRONMENTAL FATE OF PLASTICS
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Plastic production has strongly increased during the last 50 years, in 2012 world production reached a
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new record of 288 million tonnes(Figure 1).
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Europe reached about 100 kg per capita per year in 2005 and is expected to increase to around 140 kg
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per capita per year by 2015, whereas in Asian countries a growth from 20 to 36 kg is predicted.
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Use of plastic materials in North America and Western
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Figure 1. Plastics production, 1950 – 2012 adopted from PlasticsEurope.
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Plastics in the marine environment. A major part of the yearly plastic production comprises disposable
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packaging materials and other short-lived products that are discarded within a year of manufacture.
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Therefore, waste management but also improper human behaviour are important determinants of the
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amount of plastic litter in the environment. Plastic recycling and re-use varies greatly, even in Northern
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America and between European countries. As an example, in 2009 a number of European countries
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recycled more than 84% of used plastics, whereas other European countries only recycled 25% or less. In
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many other countries, only a small percentage of the plastic produced is recycled. Recently it was
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estimated that 4.8 million tonnes of plastic waste entered the oceans in 2010 from 192 coastal countries.
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Land-based sources of plastic litter in the oceans are numerous: poorly managed burials in landfills,
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riverine transport, untreated sewage, inadequate industrial control, storm discharges, wind-blown debris,
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recreational use of coastal areas, and tourist activities,
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litter is found closer to population centres, and the proportion of consumer plastic items such as bottles,
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shopping bags and personal hygiene products is higher here. In addition to land-based sources, ocean-
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based sources such as shipping and fisheries are important sources in the East Asian Seas region and
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the southern North Sea. In addition, recreational vessels, cruise liners, merchant shipping, oil and gas
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platforms and aquaculture contribute to the plastic litter in oceans.
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but important regional variations exist.
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More
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3
The buoyancy and persistence of the plastic material together with ocean circulation greatly
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affects the distribution of plastic litter over the oceans. The occurrence of macroplastics (items >5 mm in
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diameters) on the sea floor, sea surface and shorelines has been summarized by Lambert and colleagues
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(2014).
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sub-tropical convergence zones or gyres. Therefore, it may turn up thousands of miles away from
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civilization. Computer model simulations, based on satellite-tracked floats since the early 1990s, suggest
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that the plastic litter may remain in the gyres for many years.
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Plastic debris is transported by ocean currents and will tend to accumulate in a limited number of 2
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Plastic particles in the terrestrial environment. Direct release of micro (nano) meter-sized plastic
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particles into the environment is getting an important source of plastic occurrence in the environment. The
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Nanotechnology Consumer Products Inventory of the Woodrow Wilson Institute now contains 12
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consumer products containing polymer nanoparticles.
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micrometre are used in personal care products like facial cleansers,
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of toothpastes also contain micro-sized plastic particles, mostly consisting of polyethylene (see Figure
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2). Microplastics are also found in cleaning agents (scrubbers),
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clothes during washing.
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are currently not able to remove these materials because they escape the filtering process.
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not all sewage water will pass through a sewer treatment plant on its way to rivers and oceans. An
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estimation of the per capita use of microplastics in personal care products in the US population is about 1
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g per year.
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derived from washing-clothes, rather than from cleaning agents or personal care products. This is
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Microplastics with a modal size of
