North County High School students Jack Andraka and Chloe Diggs recently captured the gold medal and $50,000 in the Siemens We Can Change the World Challenge, which encourages student teams to identify an environmental issue that has global impact and provide a viable, replicable solution.

Teams were required to select an environmental topic relating to energy, biodiversity, land management, water conservation or cleanup. The two students created a biosensor to monitor water contaminants rapidly and inexpensively, and also developed an inexpensive water filter made from plastic water bottles and amino acids.

The biosensor is simpler to use than current sensors and costs slightly more than 1/200,000th of the price, while the filter is 1/42nd the price of current filters.

The two students are competing this week in the I-SWEEEP, the International Sustainable World (Energy, Engineering, Environment) Project Olympiad, this weekend in Houston, Texas. The pair will also compete in the Stockholm Junior Water Prize, which recognizes work in water and environmental science, in Sweden this summer.