KOCHI: The expedition team ‘Sea to Source: Ganges’ of the National Geographic is spearheading mammoth documentation and assessment of the microplastics in the entire length of the main Ganga river. In an email interview with Express, National Geographic Fellows Heather Koldewey and Jenna Jambeck who is leading the expedition team talk about their attempts to scientifically document plastic waste in a watershed and develop holistic and inclusive solutions. The river expedition is in partnership with The Wildlife Institute of India (WII), the University of Dhaka and WildTeam. Excerpts from the interview.
Q. What is the purpose of the ‘Sea to Source: Ganges’ river expedition? Why is it important?
Single-use plastic waste is a menacing global problem. The ocean is clogged with an estimated 8 million metric tonnes of plastic every year and rivers play a significant role, often acting like conveyor belts for plastic debris into the ocean. The river expedition is part of National Geographic’s journey to better understand and document how plastic waste travels from source to sea and to fill critical knowledge gaps around plastic flow, load and composition. The expedition will scientifically document plastic waste in a watershed and develop holistic and inclusive solutions. The more we understand about how plastic moves through our waterways, the more effective we will be at preventing plastic waste from entering the environment in the first place.
Q. Why have you chosen the Ganges for the expedition?
This is the first of several international river expeditions planned as part of National Geographic’s ‘Planet or Plastic?’ initiative, which aims to significantly reduce the amount of single-use plastic that reaches the ocean. The Ganges river was selected because it is one of the most iconic waterways in the world and supports more than 600 million people.
Q. Who all constitute the expedition team? And why an all-women expedition team?
We picked the expedition team from the top scientists around us in this field. The majority of these scientists happened to be women and so this aspect of the expedition came about organically.
Q. When does the expedition start and how will you go about studying the level of microplastics. What kind of work will you be doing?
The expedition began in early May and will last through the end of June. The expedition will focus on plastic pollution in three key areas: Land, water and people. The team working on the land portion are collecting data on the input and use of plastic in communities, how waste is collected and managed, and are quantifying the movement and type of plastic in the environment. The water team is studying plastic pollution in the air, water, sediment and the threats to species in and around the river. The socioeconomic team are surveying local communities along the expedition route to better understand awareness and perceptions of plastic pollution, household plastic waste management and local solutions for addressing the issue. During the expedition, the team will work with local stakeholders to translate its scientific findings using storytelling to raise awareness about plastic pollution and drive behavioural change.
Q. Can you elaborate on the four-dimensional investigation of plastic pollution which is being implemented during the expedition?
This is the first time there has been a four-dimensional comprehensive investigation of the plastic pollution issue at this scale across sediment, water, air and land. Data are being simultaneously collected from the same sites in four dimensions - from the air, water, sediment and people. The human component includes the types and quantities of waste generated, the types of waste management in place, and the amount of plastic waste leaking from land into water. This unique approach brings together people from different disciplines - microplastic scientists, engineers, social scientists, ecologists and materials scientists.
Q. How is the technology used for analysing the microplastics?
Microplastics are small fragments of plastic less than 5 mm in size. They are a mix of particles generated when larger plastic items break down or come from the shedding of fibres from clothes and carpets to tires. We are allowing microplastics to settle from the air into a simple collection device over a 24-hour period which is then washed and filtered onto a fine mesh. A set volume of water is pumped over a fine mesh from the middle of the river at each site, and sediment samples are collected from the riverbed. The complex analysis takes place in the laboratory after the expedition where the samples are analysed under highly controlled conditions that avoid contamination, initially to extract the microplastics from the samples and then using spectroscopy to identify the type of plastic and possible source.
Q. What do you intend to do after the expedition?
After the initial expedition this spring, the team plans to replicate the expedition to the same sites in the Ganges in fall 2019 to capture seasonal variation pre and post-monsoon. Our hope is to continue these expeditions in other major global river systems after we have successfully completed and reviewed the findings from this first expedition.