Microplastics (plastics less than 5 mm) with their ubiquitous presence and distribution is a newly recognized potential threat to aquatic ecosystems because of their direct toxicity to organisms or from the toxic pollutants, they transport. However, the majority of the research has focused on microplastic load and toxic effect on marine ecosystems rather than on the freshwater aquatic ecosystems that are more closely connected to terrestrial microplastic contamination sources.
River Ganga is the largest river in India and is a lifeline for millions of people as well as aquatic flora and fauna. However, excessive use of plastics in various sectors complemented with the scarcity of land for waste disposal and poorly developed waste management infrastructure makes River Ganga an uncontrolled dumping ground for plastics load, that may eventually put the health of its aquatic system into jeopardy. To best manage this microplastic contamination and minimize their exposure to aquatic organisms in River Ganga, it becomes highly imperative to develop comprehensive risk assessment and mitigation strategies. A well-defined monitoring strategy and quantification of microplastics contamination load, both spatially and temporally, will help to identify at-high risk zones, and thereafter accordingly develop effective monitoring and mitigation strategies. This study attempts for the first time, the spatiotemporal variation in the microplastic contamination of sediment from entire river Ganga as it passes through five Indian states starting from the rocky Himalayas to the heavily populated and industrialized plain lands. Sediments samples were collected from 55 sampling locations across the entire 2525 Km stretch of river Ganga through two seasons viz post monsoon and post-winter (2017-2018). Identification of the microplastics is performed using a Celestron Handheld Digital Microscope (Model:44308) and characterization is performed using μ-FTIR. The polymer types of particles are identified by comparing their spectra with the KnowItAll database.
The results of the study will provide a first time account on occurrence and levels of microplastic contamination for the most holy river of India i.e. river Ganga which will help decision makers in policy formulation for managing pollution sources and combating their distribution.
Key words: Ganga, Microplastic, Sediment, FTIR