When the concrete weathers, will the plastic in the bricks turn into micro-plastic?
Properly designed landfills don't exist in most of the world (Africa, Asia, most of South America).
See this report: https://wedocs.unep.org/bitstream/handle/20.500.11822/21134/...
Rapid urbanisation and comparatively high poverty (lack of access to clean drinking water, so plastic bottles are used) lead to more and more waste without proper waste management catching up.
Almost all plastic in the ocean comes from 10 rivers - 2 in Africa (Nile and Niger) the rest in Asia [0]
[0] https://www.dw.com/en/almost-all-plastic-in-the-ocean-comes-...
Plus if you ever want to modify the building you’ve got an environmental hazard on your hands.