Today a pile of trash is 50% plastic and will linger around for centuries
Today, we separate them, but in the not so distant past (our family's house in West Virginia, not excepted, didn't get telephone or electricity until the 1970s), you just dug a new outhouse when it got full.
When I asked if that meant the rare bottles he dealt in had been fished out of former toilets, the antique dealer just gave me an amused smile.
Plastic degrades to microplastics and goes into the water cycle and the air, where we breathe it in and drink it. There is suspicion that microplastics could contribute to cancer, autism, obesity, and gender dysphoria. Partly directly, partly because some of the chemicals in plastics resemble hormones, changing prenatal hormone levels, affecting the development of kids as they grow up.
This stuff is hard to study academically, as microplastics is everywhere nowadays. Particularly in household dust due to textiles made out of synthetic fibers.