Twelve-year-old science enthusiast Gitanjali Rao invented a lead detector that works in moments, inspired by the Flint water crisis. She received $25,000 in prize money for her ingenuity when she won the 2017 Discovery Education 3M Young Scientist Challenge.
"Imaging living day in and day out drinking contaminated water with dangerous substances like lead. Introducing ‘Tethys,’ the easy to use, fast, accurate, portable and inexpensive device to detect lead in water," Rao said during her contest presentation.
This seventh-grader from STEM School in Highlands Ranch, Colorado won a 3-month mentorship with Plastics Researcher Kathleen Shafer after pitching her topic to the science contest for grades 5-8. With Shafer’s help, her prototype evolved from a cardboard box to a 3D-printed device with unique software – Rao developed the app herself.
Rao’s Tethys is named after the Greek Titan Goddess of Fresh Water. It uses carbon nanotubes, tiny cylindrical carbon molecules that are very thin and strong and which are used in many applications in nanotechnology, optics, electronics and other fields. Rao first discovered them when she learned that MIT uses them for hazardous gas detection. She tells CNN that if lead is present in water, “special atoms” in Tethys’ nanotube sensor react with the lead, slowing the flow of water through the device. The resistance is then measured, sent over Bluetooth to a smartphone app, and presented in a “user-friendly scale.”
In 2014, drinking water for residents of Flint, Michigan began to be sourced from the Flint River. Over the next few years, bacteria, various other contaminants and dangerous levels of lead were detected in residents’ drinking water. About 100,000 people drank unsafe water. This was the public health crisis that inspired Rao to develop a cheap and easy-to-use lead detector.
Lead is a metal that is toxic to humans. It can damage the heart, nervous system and kidneys and is especially harmful to children, for whom it can cause developmental delays. The Environmental Protection Agency (EPA) sets the safe level of consumption at zero, but because lead is present in so many old pipes in the U.S., its admissible level is 15 parts per billion (ppb). 
Citizens, the local and state government, EPA and civil rights groups such as the American Civil Liberties Union (ACLU) become involved in a drawn-out and contentious process of securing safe water for Flint that involved numerous rounds of water testing, votes and lawsuits. In January 2016, the Michigan National Guard was called on to distribute bottled water to residents. Multiple government officials have since been charged with crimes, including manslaughter for at least 12 deaths during the crisis from Legionnaires,' a respiratory bacterial infection that typically spreads through mist from a water source. In March 2017, the EPA announced a $100 million award to Flint for upgrades to its drinking water infrastructure.
Current lead testing options include home kits or lab results, which can cost from around $10 to $100. Home tests are quick but not high in accuracy, while lab tests take several days. Roa’s prototype works in seconds. It costs about $20 to make but she thinks the production cost for a commercial version will be much lower.
"I am so confident that she will be able to take it to the market if we keep providing her help, Rao’s Teacher Simi Basu tells CBS, adding that she is a "risk taker -- she's not afraid to fail."
Rao intends to use some of her prize money to further refine her invention, to donate a portion to some of the organizations she volunteers for, and to place the remainder into her college savings fund.
