Study reveals impacts of microplastics generated from polypropylene bottles

UNSW SMaRT Centre researchers have had published a study revealing the impacts of microplastics generated from polypropylene (PP) bottles commonly used for infants and re-usable drinking.

The study - just published in the prestige Elsevier journal Environmental Nanotechnology, Monitoring & Management - investigated microplastic effects of PP, widely used for food and beverage storage.

PP has a propensity to release microplastics (MPs) and nanoplastics (NPs) under routine use conditions, and the SMaRT team investigated impacts of PP infant feeding bottles and water bottles under controlled thermal and mechanical stresses.

Supported with funding from the Australian Government under the National Environmental Science Program's Sustainable Communities and Waste Hub, headed by SMaRT and Prof Veena, the study found:

• That polypropylene bottles used for drinking water and infant feeding release substantial quantities of microplastics under conditions simulating real use.
• Particles were predominantly flake-like and irregular, with crystalline–amorphous transitions and multilayer breakdown observed.
• Baby bottles released more MPs under thermal stress, whereas surface and mechanical stresses predominated in water bottles.
• These results provide new mechanistic insights into PP degradation pathways and highlight the importance of advanced, multi-modal analytical approaches for future evaluation of nanoscale plastic release.
• Out of multiple plastic polymers, microplastics generated from PP have been identified as the dominant type in adult stool samples, comprising 62.8 % of the detected MPs.
• PP accounts for approximately 20 % of global non-fibre plastic production, making it a widely manufactured polymer.
• Due to its durability, chemical resistance, and versatility, PP is generally regarded as safe plastic, commonly used across various industries, including packaging, medical applications, and consumer goods.
• Such uses of PP pave the way for direct human exposure and environmental contamination. 

Read the research report

This report builds other recent microplastics research by SMaRT on behalf of the SCaW Hu,:

Microplastics in coastal and marine environments research

Study reveals extent of microplastics pollution in Australia