A review on state-of-the-art detection techniques for micro- and nano-plastics with prospective use in point-of-site detection

Following their initial discovery within seawater in 1972, concerns related to the abundance and occurrence of microplastics in our environment have increased exponentially since the beginning of this century. However, while several techniques have been used to analyze the plastic debris qualitatively and quantitatively, a robust, comprehensive, and reliable technique is yet to be discovered. In this chapter, a systematic review of over 200 research articles, government regulations and newsletters comprising of a brief historical background on plastics, a description of issues related to micro and nano plastics (MNPs), with an emphasis on the microscopic and spectroscopic techniques currently being used to detect them is presented. This is followed by a focus on the state of the art and potential use of point of site (POS) devices that can provide cost-effective real-time detection of MNPs including a summary on the collective use of smartphone and POS devices that meet the challenges and needs associated with MNP detection in the environment. The chapter is concluded by highlighting future aspects of MNPs research that need to be addressed, such as agreeing on global definition of MNPs, improving understanding of the degradation of plastics into smaller debris and their toxicological effect, and, most importantly, development of standardized methodologies for their quick and accurate detection, thereby facilitating tracing of their origins. This knowledge gap can be addressed by combined efforts of policy makers, researchers, scientists, industrialists, and manufacturers.