Garbage along creeks in the GTA has multiple causes:
Poverty - ie tenants being evicted, homeless persons junk collections
Teenagers - those old video cassettes are probably a porn stash. I come across socks, underwear, condoms.
1950s-1990s rural property redeveloped - some farmers and property developers left their old houses abandoned and eventually they were knocked down w/ garbage left on site
SA dumping: it's sad but even in my apartment complex, many SA immigrants refuse to dispose their garbage, eg leaving it in the hallway rather than putting down the chute, throwing it off their balconies, or my neighbors simply storing it on their balcony.
And now you see this in rural Ontario: Woolwich Dam has a 7.5km trail around it, just north of Elmira. I've been walking it for decades and literally since 2022 it's suddenly becoming a litter magnet, so much so the region has put up huge No Dumping signs everywhere. So who's doing this? Well, recently on a walk I came across a large group of TFW types tossing their fast food waste. FU!
In Northern Ontario and especially the Prairies, I associate this dumping problem with FN/poverty.
I am looking forward to my camping/hiking trip to rural Quebec and New Hampshire/Vermont, where locals respect nature and keep it clean.