This weekend, volunteers both alive and undead scoured the downtown area and local waterways to clean up trash.

It was a frightening sight, and we’re not talking about the volunteers who were dressed as zombies for the Halloween-themed afternoon cleanup. We’re talking about the massive haul of trash that was cleaned off of our roadways and rivers.

Morning volunteers gathered three shopping carts, roughly a dozen tires, a 14-foot-long saw horse and 50 other trash bags full of trash from in and near the waterways.

The zombie-fied volunteers who came out for the afternoon cleanup collected more than 40 trash bags of trash from gutters and street corners. Wayne Jones of Keep Suffolk Beautiful said there were lots of beverage containers and fast food trash plucked from the streets.

While we’re pleased that so many people were willing to take time out of their weekends to help clean up our city — although it seems some of them didn’t mind, since it gave them an excuse to dress as zombies — it’s an abysmal reflection on our city that their services were needed.

While we’re willing to concede that some trash does escape humans’ control accidentally, that sadly is likely not the major reason for all of this trash and other debris that wound up on our streets, sidewalks and rivers. The primary reason is shameful people who deliberately discard their fast-food cups, used tires, cigarette butts and other items they no longer need out into the environment rather than disposing of it in the proper manner.

There’s probably nothing we can write that would convince these selfish, ill-raised humans to behave in a manner that reflects the fact that they live in a civilized society.

However, we do thank all those who participated on Saturday — whether zombies or regular people — who helped make our city and waterways cleaner for all of the humans, animals and plants who live here. And a frighteningly big thanks goes to Keep Suffolk Beautiful for regularly organizing these events and coming up with fun themes to encourage participation.