Case Study Comparing Effects of Microplastic Derived from Bottle Caps Collected in Two Cities on <i>Triticum aestivum</i> (Wheat)

• Main Authors: Stephan Pflugmacher, Saila Tallinen, Simon M. Mitrovic, Olli-Pekka Penttinen, Young-Jun Kim, Sanghun Kim, Maranda Esterhuizen
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Environments
• Subjects: microplastic; polyethylene; weather; heat; plastic pollution
• Online Access: https://www.mdpi.com/2076-3298/8/7/64

As plastic has become an integral component of daily life, microplastic has become a ubiquitous, unavoidable constituent of nearly all ecosystems. Besides monitoring the amount and distribution of microplastic in the environment, it is necessary to understand the possible direct effects, especially toxicity and how it is affected by environmental factors where it is discarded. The present study investigated how microplastic derived from high-density polyethylene bottle caps collected in two climatically different cities, i.e., Singapore (tropical rainforest climate) and Lahti, Finland (continental climate), affected the essential agricultural grain crop, <i>Triticum aestivum</i> (L.). Wheat seedlings were exposed to microplastic derived from these collected bottle caps, as well as new and artificially aged caps, for seven days. Morphological parameters, such as root and shoot length and oxidative stress development, were measured. Exposure to microplastic derived from the caps resulted in reduced seedling root and shoot lengths compared to the controls, as well as enhanced lipid peroxidation and catalase activity. With all parameters tested, microplastic derived from Lahti bottle caps exhibited more severe effects than Singapore, which was similar to that elicited by new microplastic. The Singapore microplastic had possibly leached its toxic substances before collection due to accelerated degradation promoted by the prevailing warmer climate conditions.