Nanofabrication (2023), 8 https://doi.org/10.37819/nanofab.008.302 REVIEW A review on emerging micro and nanoplastic pollutants, heavy metals and their remediation techniques Gargi Mandal 1 , Sumit Mishra 1,* 1 Department of Chemistry, Birla Institute of Technology, Mesra, Ranchi, India. * Corresponding author: Email: smishra@bitmesra.ac.in; Mob: +918210629045. © The Author(s), 2023 ABSTRACT Plastics have become one of the most concerning pollutants today. They are non-biodegradable and potentially carcinogenic and lead to the generation of microplastics categorised as an emerging pollutant. Microplastics are plastic particles smaller than 5 microns in size. They are reported in various parts of the biosphere including human blood and tissues of various organs. Industrial and domestic effluents are two major contributing sources of microplastics in the ecosystem. A large volume of microplastics escape from the filtration processes of wastewater treatment plants (WWTP). This review studies the various removal methods for these pollutants in large-scale as well as lab-scale models and the present state of art facilities available to deal with it. Keywords: Microplastics, Emerging pollutants, Heavy metals, wastewater treatment plant Article history: Received: 18-11-2022 Revised: 18-03-2023 Accepted: 05-04-2023 INTRODUCTION With the constant industrial progress, new pollutants are being introduced into the environment. Emerging pollutants denote those pollutants which do not have any set standard limit or there are no regulations for monitoring these pollutants (Bell, 2011). The biggest problem faced with these pollutants is their impact on human health over a long period of time (Deblonde, 2011). Some of these pollutants include heavy metals, microplastics, pharmaceuticals and other persistent organic compounds. MICRO/ NANO PLASTICS Microplastics are defined as plastic fragments which are smaller than 5 mm in size. They are formed by the degradation of plastic and other synthetic waste disposed of in the ecosystem, mainly the lithosphere and hydrosphere. Microplastics are categorized into two parts based on the source of generation. They can enter the ecosystem directly, i.e., these plastic particles are originally produced in a size ranging from nanometres to micrometres. They are called primary microplastics and can be found in some industrial as well as domestic, cosmetics, and personal care products. Otherwise, they can be produced by the fragmentation and wearing down of bigger plastic pieces and are called secondary microplastics. They can form during the use or after the disposal of any plastic or synthetic product or textile (Kershaw, 2015) (Padervand, 2020). Plastic production or usage has become an important part of today's industry with the packaging industry contributing the maximum plastic waste generation of around 141 million tonnes per year. The majority of the plastic products in the packing industry have a very small 'in-use' lifetime of 6 months or less hence, resulting in a large amount of waste production. Other major industries with a huge plastic waste generation are textile, consumer & institutional products, transportation, building, and construction, etc (Ritchie, 2018). These sources generally lead to the secondary microplastic formation. Run-offs of washed clothes made of synthetic fibres consist of microfiber of the textile which generally comprises polyester and acrylics (Browne, 2011). One of the dominant causes of the degradation of plastic materials into secondary micro/nano plastic is UV radiation by the process called photodegradation. This facilitates the oxidative degradation of polymers such as polyethylene, polypropylenes, and polystyrene (Jiang, 2018). These worn-down secondary plastic particles can no longer be broken down by the natural physical and chemical phenomena and stay suspended in the waterbodies they are discharged in.