UNITED STATES (REUTERS) - 11-year-old Gitanjali Rao is "America's Top Young Scientist" with her invention of Tethys, a device that detects lead in water.

"Tethys, the Greek goddess of fresh water, is a lead detection tool. What you do is first dip a disposable cartridge, which can easily be removed and attached to the core device in the water you wish to test. Once you do that, that's basically the manual part. Then you just pull out an app on your phone and check your status and it looks like the water in this container is safe. So that's just very simple, about like a 10 to 15 second process." said Rao

Gitanjali Rao was affected by the Flint, Michigan water catastrophe when the city started using the Flint River for water in 2014, sparking a crisis that was linked to an outbreak of Legionnaires' disease, at least 12 deaths and dangerously high lead levels in children.

"I was most affected about Flint, Michigan because of the amount of people that were getting affected by the lead in water. And I also realised that it wasn't just in Flint, Michigan and there were over 5,000 water systems in the US alone. In the beginning of my final presentation at the event, I talked about a little boy named Opemipo, he's 10 years old and lives in Flint, Michigan. He has one per cent elevated lead levels in his blood and he's among the thousands of adults and children exposed to the harmful effects of lead in water. So it's a pretty big deal out there today." said Rao.

The seventh-grader said it took her five months to make Tethys from start to finish.

"My first couple of times when I was doing my experimentation and test, I did fail so many times and it was frustrating, but I knew that it was just a learning experience and I could definitely develop my device further by doing even more tests and getting advice from my mentor as well. So, never be afraid to try." said Rao.

Rao won the 2017 Discovery Education 3M Young Scientist Challenge, along with a US$25,000 (S$34,050) prize.