Detecting the presence of lead in potable water due to insufficient water treatment or transport through lead pipes is typically a time- and cost-intensive process performed by municipal utilities. To broaden the scope of water quality monitoring, University of Massachusetts researchers developed a device to bring such analytical capability into the hands of residential consumers. The handheld water-testing E-Tongue system has been evaluated through a citizen science project across four Massachusetts towns.

The device described in ACS Omega applies a voltage to a water sample, causing any lead ions present to adhere to the sensor’s gold electrode. Reversing the voltage frees the lead from the sensor and produces an electrical current, the strength of which indicates how much lead is in the water sample. If lead is present, a smartphone app linked to the device alerts the user with a color-coded reading and a concentration value that signals the severity of contamination. A green screen indicates that the lead concentration is below the U.S. Environmental Protection Agency’s (EPA) regulatory limits while a red screen denotes the lead concentration exceeds these limits.

During field trials, residents first combined a sample of their tap water with a premade buffer solution in a glass vial and then followed three steps on the smartphone app. Users clicked “start” after placing the sensor into the vial, selected “run” to begin the test and clicked “end” to save test results and share them with the researchers and local municipalities. In cases where lead concentrations exceeded the maximum allowed level of 10 ppb, the researchers verified the findings in the laboratory to confirm the accuracy of E-Tongue.

The project revealed that 10 of the 634 samples exceeded the EPA’s maximum allowed lead level of lead and confirmed that the E-Tongue’s readings were as accurate as traditional laboratory tests.