Alfalfa nanoparticles: a rapid and sustainable method for detecting mercury in water

Mercury is a naturally occurring element; however, the majority of mercury found in the environment originates from human activities, such as coal-fired power plants, mining, and waste incineration. In aquatic systems, mercury transforms into persistent forms, such as methylmercury, which bioaccumulates in food webs and poses a risk to the development of fetuses and children. Chronic exposure to persistent mercury can lead to impaired cognitive development and cause long-term health issues such as cancer. While conventional colorimetric and electrochemical sensors are effective at detecting mercury, their reliance on non-biodegradable, potentially hazardous materials raises environmental concerns. To address this limitation, we propose a novel, biodegradable fluorescent nanosensor derived from alfalfa. Alfalfa biomass, when repurposed into the nanoscale, has a natural affinity for mercury ions. After exposure to mercury, the fluorescence of alfalfa particles is quenched. This enables simple, rapid detection at concentrations ranging from 7.3 to 80 ppm in water. This research is a proof of concept for using plant-based materials as a sustainable alternative for detecting heavy metals in water environments.