A miniature device was developed for measuring trace levels of toxic lead in sediment at the bottom of harbors, rivers, and other waterways within minutes — far faster than currently available laboratory-based tests, which take days. The affordable lab-on-a-chip device could also allow municipalities, water companies, universities, schools, daycare facilities, and homeowners to easily and swiftly test their water supplies.
In addition to detecting lead contamination in environmental samples or water in pipes, a user could check whether the fish they ordered at a sushi bar has lead or mercury in it. Detecting toxic metals like lead, mercury, and copper normally requires collecting samples and sending them to a lab for costly analysis, with results returned in days. The new sensitive, inexpensive device can easily be carried and analyzes samples on-site within minutes to rapidly identify hot spots of contamination.
The research focused on analyzing lead in sediment samples. Many river sediments in New Jersey and nationwide are contaminated by industrial and other waste dumped decades ago. Proper management of contaminated materials dredged from navigational channels is important to limit potential impact on wildlife, agriculture, plants, and food supplies. Quick identification of contaminated areas could enable timely and cost-effective programs to manage such materials.
The new device extracts lead from a sediment sample and purifies it, with a thin film of graphene oxide as a lead detector (graphene is an atom-thick layer of graphite — the writing material in pencils). More research is needed to further validate the device's performance and increase its durability so it can become a viable commercial product.