Conclusions and Future Needs

Abstract

Currently, plastic is considered as one of the widely used synthetic polymers around the globe. Due to its extensive usage, some billion tons of litter/waste (plastic-based) gets accumulated in the environment in different parts of the world per annum. Most of the generated plastic-based waste was reported along the coastal lines. Jambeck et al. (2015) reported percent of mismanaged plastic waste generated per year in coastal area of China (76%), Bangladesh (89%), the United States (2%), Pakistan (88%), Indonesia (83%), and India (87%) in 2010. Based on the literature survey, it can be concluded that the main cause of plastic pollution is its very slow rate of degradation process as it needs about 1000 years to degrade in nature (Shah et al. 2008; Sangale et al. 2012; Mukherjee and Chatterjee 2014). In the marine environment, due to ingestion of plastic waste or entanglement with the plastic waste, about one million deaths of marine biota per annum were recorded (Azzarello and Van Vleet 1987; Rutkowska et al. 2002; Shah et al. 2008). It was also documented that direct sunlight results in the release of some toxic chemicals from the plastic waste, e.g., phthalates (Giam et al. 1978; Teuten et al. 2009). Phthalates was reported to have deteriorating effects on the normal functioning of the mammalian endocrine glands (Li et al. 2004). In most of the metropolitan cities, during monsoon, the littered plastic waste was found responsible for choking of drainage systems and leads to create flood-like situations, e.g., Mumbai floods. Besides causing flood-like situations in the cities across the globe, it was also observed that at dumping sites, the thrown off plastic carry bags with discarded food material were ingested by terrestrial animals and were found responsible for their death. Besides the macroplastic, a new term, microplastic, is reported in literature (Thompson et al. 2004). As per the guidelines of the US National Oceanic and Atmospheric Administration (NOAA), microplastics (MPs) cover all types of plastic material with size ranging from 1 nanometer to <5 mm (Arthur et al. 2009; Andrady 2011). Microplastics are of two types based on their source, viz., primary microplastic and secondary macroplastic. Primary microplastics are the minute plastic particle with size ranging from 1 mm to 5 mm (Cole et al. 2013; Boucher and Friot 2017), directly generated from the primary source, and are used in soap, shampoo, toothpaste and other cosmetics, medicine (Boucher and Friot 2017), air-blasting technology, etc. (Derraik 2002). The plastic particle generated by the degradation or littering of the macroplastic due to various environmental forces or anthropogenic activities is said to be secondary microplastic. At the global level, seven key sources of the microplastic are identified as city dust, marine coatings, personal care products, plastic pellets, road markings, synthetic textiles, and tyres. As per report in 2014, around 15–51 trillion microplastic pieces (equivalent to 93 thousand to 236 thousand metric tons) were estimated in the oceans at the global level (Boucher and Friot 2017). Compared to macroplastics, microplastics were reported to be more detrimental and lead to deaths of millions of marine animals of belongs to different 180 species (Cole et al. 2013; Wang et al. 2016).