**1. Introduction**

Due to the permanence and robustness, plastic has infiltrated every aspect of life like in clothing, electronics, cleaning products as well as in building materials [1]. World production of synthetic organic polymer plastic has skyrocketed from 1950 to 2013, showing an escalation from 1.5 to 299 million tons. Around 8-16 million tons plastic waste invades sea and oceans annually, substantial section of which comes from land borne sources [1, 2]. In the very beginning more attentiveness was towards large plastic debris; however prevalence of smaller plastic particles in the marine environment elucidated in early 1970's [3, 4]. Due to minuscule proportion of microplastics they are ingested by protozoans to marine mammals and by many filter feeders [5]. Amphipods, polychaete worms, barnacles and sea cucumber ingest microplastic which gets accumulated in food web [6]. According to Setälä et al. [7] and Green et al. [8] microplastics are omnipresent in nature and possess high potential to interrelate with environment (biotic and abiotic) thus menacing with biogenic domain of flora and fauna. Presences of microplastics were perceived more in aquatic ecosystems, surface waters, sediments and water column. Deep seas and mountain lakes were also sullied by the presence of microplastics and thus scrutinized as global pollutant [9, 10]. Worldwide pollution provoked by plastic is dispersed maximum across seas and oceans. Longevity and buoyancy are some properties that have led these pollutants fall under the category of hazardous waste [11–13]. In the environment microplastics are present in heterogeneous group,

according to varying size and shape, specific density and composition. Prodigious plastic wastes are easily perceptible [14, 15]. Although microplastics are inconspicuous, their dissemination into the oceans has profound repercussions leading to cumulative effect in the food chain [16].

Microplastics may pose a risk to aquatic environments due to their documented ubiquity in marine ecosystems, long residence time, and propensity to be ingested by biota. As Microplastics from different sources ultimately reaches water bodies and from here microplastics disperse into surface water, underground water, and benthic sediment, etc. and their bioavailability gets affected [17]. After consumption or ingestion, microplastics can remain in the digestive tracts of aquatic organisms for periods of days to weeks before excretion. The more time of excretion likely allows the transfer of microplastics both up the food web and to new geographic locations. Exposure of individual aquatic organisms to microplastics may negatively impact feeding, growth, reproductive capabilities, or survival [18]. While studies and reviews on plastic pollution in the marine environment are increasingly common, to date, few studies have assessed the sources, fate and impact of microplastics in freshwater as well as marine environment. Thus, the present article has been made in order to fill the lacuna in this regard.
