The Ganges River – with the combined flows of the Brahmaputra and Meghna rivers – could be responsible for up to 3 billion microplastic particles entering the Bay of Bengal every day, according to new research.
The study represents the first investigation of microplastic abundance, characteristics and seasonal variation along the river and was conducted using samples collected by an international team of scientists as part of the National Geographic Society's Sea to Source: Ganges expedition.
Over two expeditions in 2019, 120 samples (60 each in pre- and post-monsoon conditions) were gathered at 10 sites by pumping river water through a mesh filter to capture any particles.
The samples were then analysed in laboratories at the University of Plymouth with microplastics found in 43 (71.6%) of the samples taken pre-monsoon, and 37 (61.6%) post-monsoon.
More than 90% of the microplastics found were fibres and, among them, rayon (54%) and acrylic (24%) – both of which are commonly used in clothing – were the most abundant.
Combining predicted microplastic concentration at the mouth of the river (Bhola, Bangladesh) with the discharge of the river, scientists estimate that between 1 billion and 3 billion microplastics might be being released from the Ganges Brahmaputra Meghna River Basin every day.
The research, published in Environmental Pollution, was led by researchers from the University of Plymouth’s International Marine Litter Research Unit, working with colleagues from the Wildlife Institute of India, University of Dhaka, WildTeam, University of Exeter, National Geographic Society and the Zoological Society of London.