Toxic heavy metal contaminants (HMCs) pose a serious threat to human health globally even at trace levels. Whether a cause of heavy metal contamination of drinking water is unintentional (natural disaster such as hurricanes, tornados, earth-quakes or tsunamis), unintentional-avoidable (such as aging of water supply infrastructure or usage of low quality materials) or aggressive-avoidable (usage of compromised water filters), such contamination will adversely affect people of all ages. Seniors and children are most vulnerable and therefore testing of HMCs in school and hospital drinking water supply systems is most critical. There is a strong need for developing a sensor technology for reliable, instant and sensitive detection of HMCs. Dr. Santra's team is developing hand-held sensor device prototype (comparable of a size of a business card holder) using quantum dot nanotechnology for instant detection of Cd, Hg, Pb, As and Cu contaminants in drinking water at trace level. This technology will allow for simple and rapid evaluation of HMCs before consumption.