7 Unlikely Threats to the Planet Mobile phones and concrete are on the list By John Johnson, Newser Staff Posted Apr 22, 2010 4:21 PM CDT 30 comments Comments A 1996 image from the space shuttle Endeavour. (Getty Images) (Newser) – Environmental hazards lurk everywhere, says LiveScience, which rounds up 7 "secret polluters." A sampling: Cell phones: They use a rare mineral called coltan, which mainly comes from Congo via unsound mining methods. Plus, the phones have toxic chemicals that can pollute upon disposal. Concrete: The way it's manufactured is "carbon intensive." Worse, all that concrete in cities keeps rain water from entering the soil, which means it ends up in municipal systems and often overwhelms them. Public parks: As weird as it sounds, these parks require lots of watering, fertilizer, and maintenance and may actually contribute to climate change. Pets: Rover "contributes as much greenhouse gas to the atmosphere as a large car." Read the full list here.