03/25/2013—In the end, it call came down to fracking, disease, 70,000 bottle caps, and a few other major eco-related topics.

Last week, the Lexus Eco Challenge awarded 10 winners the last of this year’s $500,000 prize money (in scholarships and grants). For those unfamiliar, the Lexus Eco Challenge, sponsored by Lexus and Scholastic, invites middle school and high school teams to devise inventive ways to make a difference in their communities—and then inspire environmental action around the world.

More than 400 teams entered this year’s contest before 32 were chosen to compete in the final round. Just a few ideas from this year’s winners:

Disease prevention: For their entry in this year’s Land & Water challenge, the Grand Prize-winning team from Arlington High School, in New York, took on the abnormally high number of Lyme disease cases in its community. (Lyme disease, carried by ticks, is serious business; if not caught early, it can lead to chronic neurological problems.) The team went big, leaning on the Center for Disease Control and Prevention to re-issue the Lyme disease vaccine.

Just where do you put 70,000 plastic bottle caps?: The other Grand Prize-winning team, the Eco Hawks from South Carolina’s Hanahan Middle School, used their state’s reportedly low enthusiasm for recycling as an incentive to get the word out. The results are quite inspiring: The team partnered with dozens of local organizations and spoke to the House of Representatives; their program yielded a 16 percent increase in local curbside recycling, and the students collected nearly 70,000 plastic bottle caps for recycling.

Attacking fracking: While the practice of fracking (drilling and firing liquid into the ground to extract natural gas from rocks) threatens water and air safety for the West Geauga High School’s community, the school’s Lexus Eco Challenge team found that the same problems are affecting people in Guatemala. They partnered with the Social Entrepreneur Corps and Community Enterprise Solutions to distribute water filtration units and cook stoves to families and schools in rural Guatemala.

Drilling down to DNA: For the purpose of supporting reforestation efforts, the Riptides team, from Clark Magnet High School in California, qualified for the final challenge by cultivating a native plant garden that conserves a whopping 336 gallons of water per week. For the final challenge, though, the team went micro by exploring native plant DNA sequences with researchers at Coastal Marine Biolabs.