Ah summer — the time of camps and family reunions where every person gets the same cheap T-shirt to wear. If you've wondered what the environmental impact of all those T-shirts are, here's a video from clothing recycler USAgain that may shock you. Turns out, those freebie T-shirts are responsible for chemical fertilizers, pesticides, carbon emissions and a whole lot of water pollution.

Opting for eco-friendlier T-shirts made locally will lower those numbers. But I've said it before and I'll say it again: Opt for pre-loved fashions before buying new — even if the new duds you want are from eco-friendly companies! According to the video, the water used during the lifecycle of a single T-shirt is a whopping 700 gallons, a lot of which could be saved simply by buying a more affordable, just-as-cute pre-loved T-shirt at your nearest Crossroads or Buffalo Exchange.

That used T-shirt will still require water to wash and power to dry, but hopefully you've got a hand-washing, line-drying, or energy efficient laundry system to reduce that environmental impact.

And of course, the greenest T-shirt of all is the one already in your closet. How long have you had your oldest T-shirt — that you still wear on a regular basis?

Also on MNN: Your T-shirt's life story (before it met you)

The eco-impact of a T-shirt
Watch this video to see just how much a single T-shirt can affect the environment.