4 ms·

Animals come in all sizes, and the big ones depend on the little ones. And so, ad infinitum.

• smsm42 11y ago
  This is true, but what I am trying to understand is why sand and dust does not hurt these animals but microbead particles of the same size do.
  • rleigh 11y ago
    Two factors. 1) Density. Sand and dust settle out. Plastic has a lower or similar density to water, so will collect at the surface or float in the water column. 2) Structure and surface properties. Plastic is hydrophobic and usually not completely solid--it is more of a sponge at the microscopic level. This means it can adsorb and absorb oils, which in turn can absorb biologically active chemicals from the water, effectively concentrating them. This basically means that small organisms at the lower end of the food chain can end up ingesting these, including all the nasty stuff, and these cause problems up the food chain, either by killing or reducing the turnover of the lower organisms, starving the higher organisms of nutrition, and also by concentrating the toxins up the food chain.
    • smsm42 11y ago
      I wonder if density issue can be fixed - i.e. if it's possible to make microbeads with density/specific gravity that would make them sink. AFAIK, there are plastics/compounds like that. Not sure how hard is to fix the absorption issue.