Message in a bottle: Open source technology to track the movement of plastic pollution

TLDR

Rivers worldwide act as major transport pathways for plastic pollution, discharging large quantities of waste into the ocean, yet the transport and fate of plastic through riparian systems remain largely unknown despite prior oceanographic modelling and drifter data. This proof‑of‑concept study applies open‑source GPS and satellite tracking technology to 500 ml PET bottles in the Ganges River system and Bay of Bengal to demonstrate feasibility and explore widespread use for monitoring plastic movement. The bottle tags, built with appropriate shape, size, and buoyancy, combine cellular GPS and satellite links to replicate true plastic bottle movement patterns and enable long‑range tracking. The tags were successfully tracked 2 845 km over 94 days from the Ganges to the Bay of Bengal, showing that this technology can monitor plastic dispersion and serve as a tool for behavior change, policy, and outreach.

Abstract

Rivers worldwide are now acting as major transport pathways for plastic pollution and discharge large quantities of waste into the ocean. Previous oceanographic modelling and current drifter data have been used to predict the movement and accumulation of plastic pollution in the marine environment, but our understanding of the transport and fate through riparian systems is still largely unknown. Here we undertook a proof of concept study by applying open source tracking technology (both GPS (Global Positing System) cellular networks and satellite technology), which have been successfully used in many animal movement studies, to track the movements of individual plastic litter items (500 ml PET (polyethylene terephthalate) drinks bottles) through the Ganges River system (known as the Ganga in India and the Padma and Meghna in Bangladesh, hereafter known as the Ganges) and the Bay of Bengal. Deployed tags were successfully tracked through the Ganges river system and into the Bay of Bengal. The “bottle tags” were designed and built (e.g. shape, size, buoyancy) to replicate true movement patterns of a plastic bottle. The maximum distance tracked to date is 2845 km over a period of 94 days. We discuss lessons learnt from the development of these plastic litter tags, and outline how the potential widespread use of this open source technology has the ability to significantly increase understanding of the location of accumulation areas and the timing of large inputs of plastic pollution into the aquatic system. Furthermore, “bottle tags” may act as a powerful tool for stimulating social behaviour change, informing science-based policy, and as valuable educational outreach tools for public awareness.