As agriculture uses more plastic, microplastics—smaller plastic particles that result from breakdown—are showing up in soil. To reduce pollution, biodegradable plastics are often used as alternatives. But how safe are they for crops and the environment?
This study tested biodegradable microplastics (BD-MPs) made from PBAT (a plastic-starch blend) on lettuce plants using a special climate-controlled system called CLIMECS.
Key findings:
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BD-MPs had minor negative effects on lettuce growth, such as:
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Lower dry weight
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Reduced leaf area
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Less carbon and nitrogen in the leaves
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More importantly, BD-MPs caused significant changes in plant biochemistry:
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Lower chlorophyll levels (important for photosynthesis)
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Increased signs of oxidative stress (a kind of cell damage)
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Activation of plant defense mechanisms to cope with stress
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Thus, even though marketed as environmentally friendly, biodegradable microplastics can still stress plants and affect their health. This highlights the need to study bioplastics more carefully before assuming they are completely safe for agriculture.