By Anthony Clark, Plastics & Rubber Weekly
A new study has shed light on the sustainable credentials of bio-based plastics. It indicates that no bio-based plastics are sustainable, owing to practices including pesticide use.
However, this could change with further technological development, according to the authors of 'Sustainability of bio-based plastics: general comparative analysis and recommendations for improvement,' published in the Journal of Cleaner Production.
The researchers measure the evidence for the sustainability of bio-based plastics. These assessments were based on the materials' environmental, health and safety impacts throughout their lifecycle.
The study considered possible sustainability issues to be those that arise from using genetically modified food and hazardous pesticides to cultivate the feedstock (such as corn and soya), the use of hazardous chemicals during production and processing, the use of harmful additives or untested materials for which health effects are not well known, potential hazards in workplaces, as well as efficiency in the use of resources including water, energy and materials.
According to the authors, although in some aspects bio-based plastics are more sustainable than traditional plastics, their analysis identified several environmental and occupational health and safety hazards in their production.
Some bio-based plastics are preferable from a health and safety perspective; these include polyhydroxyalkanoates (PHAs), poly-lactic acid (PLA) and starch. However, they also have some potential hazards, for example, production of PHA may expose workers to chemicals that are possibly carcinogenic, and PLA production uses a tin-based chemical that could have toxic effects on the hormonal system.