Why not outlaw low density plastics that cause ocean pollution?

Question

I know it costs. But we got rid of chlorofluorocarbons and are preparing to eliminate stuff like coal! This in between.

Proposal: By international agreement get rid of floatable PE, HDPE and PP and the like, for single use small items. If you make bottles and bags of this, you know what happens.

Make that stuff out of PVC and other plastics that sink. As a side effect you sequester that carbon. At the bottom of the ocean with mud over it, it is gone for timescales that worry us.

This would all but wipe out ocean plastic pollution at modest cost. What am I missing?

Answer 1

Make that stuff out of PVC and other plastics that sink.

Yes, we should be sequestering petroleum-based products like plastics, but there are nicer ways to go about it than letting it sink to the bottom of the ocean. Animals live on the ocean floor, even in the deep recesses of the Mariana Trench, so any plastic finding its way down there is more likely to be eaten by fish & crustaceans, which would eventually make its way up the food chain into humans.

A better alternative would be to stop plastics from reaching the ocean in the first place. Similar to your suggestion about legislating away from floatable plastics - A few governments have simply begun banning single-use plastics altogether, mandating more eco-conscious alternatives instead:

• Australia-wide bag ban leads to 1.5 billion fewer plastic bags in the environment _news.com.au
• Ban on single-use plastics from 1 March 2021 _{South Australia Government | epa.sa.gov.au}
  
• Single-use plastic items ban _{Queensland Government | qld.gov.au}

In addition, there have been a few stories about people and companies attempting to tackle the plastic waste problem, by recycling more types of plastic into new products.