The reader will also find presentations on molecularly imprinted polymeric nanocomposites, critical and comparative comments on Nano-biosensors and Nano-aptasensors and on applications of nanotechnology for the remediation and purification of water with a main focus on drinking water. The last chapter presents a comprehensive review on plasmonic nanoparticle based sensors whereby the authors have hypothesized the future applications in the environment which can be plausible in the near future.