Pure Biodegradable plastics needed
By: Vijay Kumar H K
Compostable carry bags do not compost in all circumstances as per study. However, in order to compost these products, a separate composting facility with specific environmental conditions must be built in accordance with widely accepted international standards such as IS/ISO and ASTM.
The conditions required for the decomposition of compostable bags do not exist in the municipal landfills. Compostable plastic packaging is not a blanket solution, but rather one for specific, targeted applications.
Most compostable plastics are more expensive as compared to conventional plastics. As of now, raw material for compostable plastics is not available in sufficient quantities in India.
Further, there should be a clear identification of these products to distinguish from other conventional plastic products. Recycling of conventional plastic products gets adversely affected if conventional plastics and compostable plastics are mixed.
In another technology, plastic carry bags that are oxo degradable and biodegradable are manufactured by adding a small amount of ‘catalyst or pro-degradant additive’ to conventional grades of polyethylene/polypropylene and using the same process as conventional carry bags.
The degradation of these bags is evaluated in accordance with international ASTM standards. According to the industry, the base polymer degrades into lower molecular weight under favourable environmental conditions of heat, oxygen, and sunlight. It is claimed that low molecular weight degraded plastics will degrade biologically, releasing carbon dioxide, water, and biomass.
These claims have not been supported by scientific evidence. The final Report of the Commission to the European Parliament and the Council, Brussels, raised concerns about the potential toxic effects of oxidising additives, in addition to the resulting microplastics, in both land and marine environments. More scientific research is needed to validate the claimed oxo- and bio-degradability of these plastics.
(The author hails from Raichur, Karnataka and is an active environmentalist)
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