Argus is a living plant with DNA nanosensors inside it that detects lead (Pb2+ Heavy Metal). Irregularities in industrial waste management has lead to depletion of water quality in rivers in many regions. Current processes of monitoring the water quality are not realtime (taking a week or longer) or require special systems that are not off-the-shelf. Through Argus, we propose a novel water monitoring method where plants provide an optical readout of lead in water. A DNAZyme is used as sensor assay—double stranded DNA that breaks into single stranded on contact with Pb2+ and binds to single walled carbon nanotubes. This sensor assay can be injected inside the leaf of a plant and stays within the intercellular space.