June 5, 2019

expert reaction to human consumption of microplastics

Research published in Environmental Science & Technology demonstrates that in approximately 15% of Americans’ caloric intake, annual microplastics consumption ranges from 39000 to 52000 particles depending on age and sex. 

Prof Richard Lampitt, leader of the Microplastic Research Team, National Oceanography Centre, said:

“I think that the press release is largely well balanced and reflects the conclusions of the paper. Furthermore, I think the paper is a careful assessment of the data which has to date been published and that the conclusions are sound.

“My major criticism of this paper (and many others) is that there is no definition of the term microplastics. Specifically; the measure of abundance is highly dependent on the lower size boundary selected (1, 10 or 100 micron) and to a lesser degree on the upper boundary (1mm or 5mm). Particle size is only mentioned in passing in the first paragraph and then again in the semi-final paragraph and yet this has a massive effect on the data presented and the conclusions reached. That being said, it is likely that the estimates of exposure presented in this paper will be a minimum as many of the studies on which they build their data base will have failed to detect very small particles such as in the range 1-10 micron which some people consider to be within the definition of the term microplastics which others consider these to be nanoplastics and outside of this present study.”

Prof Alastair Grant, Professor of Ecology, University of East Anglia (UEA), said:

“The authors calculate consumption of microplastics from measured concentrations in food and air. They calculate that an adult male consumes 142 plastic particles per day by mouth and inhales another 170. The rather large numbers that are given most prominence are annual estimates. No evidence is presented that these rates of consumption are a significant danger to human health.

“The figure for inhalation is calculated by multiplying particle concentrations in air by daily respiration rates but does not take into account the systems that our bodies have to remove particles from the air that we breathe.  One of the two sources for particle concentrations in air says that the observed fibers are too large to be inhaled so, the numbers of particles that actually reach our lungs will be much smaller than the numbers quoted.”

Dr Stephanie Wright, Research Associate, King’s College London (KCL), said:

“There has been an awareness of microplastic contamination of dietary products and air for several years. This study reiterates what is already known of microplastic exposure, synthesizing the existing evidence.

“Some of the included studies should be interpreted with caution, especially those which only rely on visual means to identify microplastics. Size is an important parameter when considering the implications of (any) particle exposure. Without this information, it is difficult to interpret the current findings beyond the fact that we consume microplastics.

“These current estimates suggest microplastic exposure is relatively low compared to other particles. For example, it has previously been estimated that the average Western diet exposes consumers to billions of titanium dioxide microparticles, a common additive, each day. However, what (comparatively) low microplastic exposures mean for health is unknown.

“Further research to quantify exposures to smaller microplastics, for example in air, is now needed.”

‘Human Consumption of Microplastics’ by Cox et al. was published in Environmental Science & Technology at 13:00 UK time on Wednesday 5^th June 2019.

Declared interests

Prof Richard Lampitt: “No conflict of interest.”

Prof Alastair Grant: “I don’t have any conflicts of interest.”

Dr Stephanie Wright: “I have no COIs.”