The need for ecologically realistic studies on the health effects of microplastics

Abstract Plastic pollution is now so widespread that microplastics are consistently detected in every biological sample surveyed for their presence. Despite their pervasiveness, very little is known about the effects of microplastics on the health of terrestrial species. While emerging studies are showing that microplastics represent a potentially serious threat to animal health, data have been limited to in vivo studies on laboratory rodents that were force fed plastics. The extent to which these studies are representative of the conditions that animals and humans might actually experience in the real world is largely unknown. Here, we review the peer-reviewed literature in order to understand how the concentrations and types of microplastics being administered in lab studies compare to those found in terrestrial soils. We found that lab studies have heretofore fed rodents microplastics at concentrations that were hundreds of thousands of times greater than they would be exposed to in nature. Furthermore, health effects have been studied for only 10% of the microplastic polymers that are known to occur in soils. The plastic pollution crisis is arguably one of the most pressing ecological and public health issues of our time, yet existing lab-based research on the health effects of terrestrial microplastics does not reflect the conditions that free-ranging animals are actually experiencing. Going forward, performing more true-to-life research will be of the utmost importance to understand the impacts of microplastics and maintain the public’s faith in the scientific process.