A solution to single use plastic bags.

Sandra Pascoa in her laboratory with sheets of biodegradable natural plastic produced from the nopal. 
EFE / Carlos Zepeda

The Nopal Cactus may provide a solution to the plastic bag pollution problem.

In 2018 Australia banned the use of single use plastic bags. These bags were provided free to shoppers at supermarkets and by 2016 it had been estimated that 5 billion of these bags were used annually in Australia alone and that around 150 million of these ended up as roadside litter (1) with as much as 8 million tons ending up in the ocean worldwide annually (2). Worldwide use of these bags amounted to around 1 trillion bags annually (3). These bags presented a number of problems to wildlife, particularly oceanic wildlife, as the bags that found their way into the sea caused either death by entanglement (4) or presented a danger to larger sea creatures such as dolphins, whales and seals who mistook them for food and consumed them (5). It has also been estimated that annually around 1 million birds die from plastic bags as well (6). These problems are exacerbated by the fact that it may take as little as 10 to 100 years (7), or as long as 1000 years (8) for these bags to breakdown and each bag has the potential to kill or injure many animals in its lifetime. Most of these bags don’t biodegrade but simply breakdown into smaller particles known as microplastics (9) which cause further environmental and health issues (10).

In June 2018 Mariana González published that Sandra Pascoe from the University of Valle de Atemajac in Guadalajara was in the process of providing a potential solution to the problem of replacing these non-biodegradable single use plastic bags. Since 2014 she has been developing a “plastic” from the juice of the nopal species Oputina ficus-indica and Opuntia megacantha. The nopal cactus is noted for its “baba” or viscous juice which it exudes during the cooking process. This juice is composed of monosaccharides, polysaccharides, pectin and organic acids. Sandra has developed a method of combining the nopal juice with gylcerin, natural waxes, proteins and dyes to produce thin, durable sheets. The material produced can be denatured by water and decomposes readily when buried in earth. Current tests are in the process of performing the thermal and density tests of the plastic to know how much weight it can resist if it is transformed into bags and hardness and resistance tests have indicated that it can be melted and put into moulds and that it may be used to create low density materials such as containers for cosmetics, bases for scientific prototypes, costume jewellery or toys (11).

  1. Cormack, Lucy (9 April 2016). “Australia falling behind third world on global map of plastic bag bans”. The Sydney Morning Herald. Fairfax Media. 13 September 2017.
  2. https://www.marineconservation.org.au/ocean-plastic-pollution/
  3. https://www.reusethisbag.com/articles/plastic-bag-bans-worldwide/
  4. Approximately 100,000 marine creatures a year die from plastic entanglement. http://oceancrusaders.org/plastic-crusades/plastic-statistics/
  5. https://www.wwf.org.au/news/blogs/plastic-in-our-oceans-is-killing-marine-mammals#gs.fi5p8g
  6. http://oceancrusaders.org/plastic-crusades/plastic-statistics/
  7. http://business-ethics.com/2010/09/17/4918-plastic-grocery-bags-how-long-until-they-decompose/
  8. http://storage.neic.org/event/docs/1129/how_long_does_it_take_garbage_to_decompose.pdf
  9. Small pieces of plastic, less than 5 mm (0.2 inch) in length, that occur in the environment as a consequence of plastic pollution. https://www.biologicaldiversity.org/programs/population_and_sustainability/sustainability/plastic_bag_facts.html
  10. https://www.marineconservation.org.au/ocean-plastic-pollution/
  11. https://www.efeverde.com/noticias/mexico-plastico-biodegradable-jugo-nopal/

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