Hello Woody,
In Manaus, the city is very littered, trash everywhere. From what I've seen, though, they are better with eco-friendly transportation than the United States is. Mostly everyone there drives small cars and trucks or motorcycles. Also along the river we sometimes see plastic bags and bottles and cans in the river. I don't think the indigenous people of the Rio Negro understand all of the effects littering can cause to the river, as well a the plants and animals native to the river. It might help to educate these people about the consequences of polluting this amazing area.