The purpose of this chapter is to review the latest trends in the use of nanomaterials (nanoparticles, quantum dots, nanotubes, etc.) as well as miniaturization and lab-on-a-chip technologies for nucleic acid based biosensing systems with interest for environmental applications. Although most of the principles of nanomaterial-based sensors have been addressed earlier, in this chapter we aim to focus on the DNA and nanomaterial-based systems that are of interest for environmental applications. In addition to nanomaterials the chapter will also consider lab-on-a-chip systems involving DNA as a novel trend in environmental monitoring. Due to the lack of relevant reports in the literature on specific DNA-based systems, other analytes will be also discussed for some of the detection modes reviewed here, keeping in mind future extension of these methods as possible alternatives for DNA-based environmental monitoring.