Zero in on Plastics
by Devina Anglingdarma • 19 November 2021

Muhammad Reza Cordova refused to be called a researcher despite his years-long experience at the Research Centre for Oceanography in the Jakarta-based National Research and Innovation Agency (BRIN). “I prefer that you call me a marine waste picker because I love cleaning and picking litter from the environment!” he said jokingly during our online interview.

Dr Cordova’s research interest in marine pollution, ecotoxicology, and environmental stress has led him to contribute to a study on plastic pollution in the Indonesian marine ecosystem. He has delved into the distribution, temporal and seasonal variations, dynamics, associations with other types of pollutants and their impacts, as well as solutions to problems of marine litter.

The scientist is also fluent in monitoring and estimating plastic leakage or known as the plastic footprint. In short, he tracks the plastic pathways from our landfill into the sea – from plastic production to its end cycle when the plastic has become a waste. He also estimates how much of our plastic end up in the ocean and beyond. Here is the excerpt of our conversation with our expert.

RKC-MPD ERIA: Could you describe briefly your research activities in leakage estimation and monitoring?

Dr Cordova: Since 2015, I have been interested in studying marine plastic pollution. When I am on the field, I take samples in the marine environment to see the impact of plastic. Additionally, I track the distribution of the plastic and see the microplastic, whether they are in the water or the sediment. Finally, I also research its impact on marine biota if they ingest these particles.

Why is it arduous to calculate leakage estimation? Could we use satellites to detect plastic debris?

Satellites can only detect plastic on the surface of the water but not ones that are buried in the soil or stuck in the water column. This will remain a challenge until we have someone who can write the algorithm to detect them sinking marine plastic.

What affects the estimation when calculating plastic leakage?

Estimation method to determine leakage variables is still a subject of debate. There is a consensus that marine plastic debris is predominantly caused by trash leakage. However, regionally, different variables originated from varied pathways, which also depends on local characteristics. For example, the population densities, the GDP, the cultural habit, and the effectiveness of the local infrastructure are amongst the variables we monitor that contribute to plastic leakage.

We now know that rivers are one of the major pathways that bring plastics and microplastic debris into the ocean. Can you tell us about the relationship between landfills and this major water pathway?

Landfills could be one of the sources of marine plastic debris. We found that microplastic rates found in the river after landfill area outlets are three to four times higher than the upstream. At first, we thought the culprit of these microplastic leakages was Galuga Landfill alone since it is the only open dumping site among the three landfills in the area.

This year, after monitoring the microplastic from the midstream of the Cisadane River to its downstream, we found that the leachate water from landfills also contributes gravely to the microplastic into the river.

What is leachate water? And why is it a problem?

Leachate water is the water that leaks from each garbage dumped in the landfill site. As an example of why it is a problem, we were monitoring Benoa Bay in the North of Bali in 2017 and 2018, and we wondered why the north area of this bay has the highest microplastic abundance. It turns out there are two pipes of leachate water outlet just next to our site from Suwung Landfill. That was when we first suspected that leachate water potentially releases microplastic into waterways and the sea.

What is the importance of harmonizing leakage monitoring and estimation?

Until today, there is no available methodology on how plastic pollution monitoring research must be carried out. Therefore, there needs to be a harmonized method. Several guidelines in monitoring plastic litter exist in UNEP, Japan, Korea, Europe, the United States, and Australia. Including our government in Indonesia. We have different approaches, sampling tools, different extraction methods, and lab conditions. Although we may all share the same objective, so long as we do not have a common technique, we could not compare the data from apple to apple.

Take the example of Indonesia. It is a big country with most cities having their own universities. The plastic litter data is critical scientific evidence to identify debris hotspots, as well as to predict future leakage and the debris’ movement. When we try to peer review their findings, the various adopted methodologies to estimate plastic leakage make this work difficult.

The method harmonization plays a role to make it easier to build an effective policy to tackle plastic litter. The characteristics of the debris in each area are different and using different rules could cause underestimation or overestimation of plastic leakage in a region.

How far do our plastics go, and what is the implication?

From our findings in the Jakarta Bay model, our debris tends to float toward the eastern part of Indonesia and the Indian Ocean in all seasons.

Consequently, the debris will pass the Sunda Strait before heading towards the Indian Ocean because the ocean current will bring all the water mass from the eastern part to the west.

Plastic litter do not have passports, so we know they could cross the border with ease. But before they cross the border, they would impact the local areas first. So, for instance, 60 per cent of the debris from Jakarta Bay are bound to land in the north of Java, in the Thousand Islands to Lampung and some areas in Enggano Island (Bengkulu Province, Indonesia).

The Ministry of Marine Affairs and Fisheries deployed ten drifters from Cisadane River. Three of them got stranded in Seribu Islands, and three others ended up in Jakarta and north of Java. One found its way to Lampung, another in Enggano Island, while two went directly to the Indian Ocean. The last time I saw the drifter checker was two months ago, and those two that went to the Indian Ocean were already in the south of Africa in less than one year.

So, some of the litter from Indonesia is accumulating in the Indian Ocean garbage patch. This patch stems from the rotating movement of the oceanic current called ‘gyres’ – where the ocean current never stops because of the wind, moon, and the earth’s rotation. That non-stop rotation makes the accumulation of litter in the middle of the sea.

The unwelcome news is, Indonesia is near the Indian Ocean gyre and the North Pacific gyre, which makes it even easier for not just domestic but also regional trash to accumulate near our country. And Indonesia is the place where the coral reef triangle exists. Imagine if our corals interact with the local debris on top of the trash from surrounding regions–it becomes a threat to our marine biodiversity.

What is the most prominent challenge in estimating our plastic leakage into the ocean?

See, the theoretical framework and the pathway are clear. But the problem is, again, the supporting data. The data variable and the data itself are essential, but most of the areas lack data availability. That is the challenge in forecasting plastic pollution into the ocean.

What does your organization do to harmonize monitoring and reduce plastic waste leakage into the ocean locally?

Now we are calibrating with other organizations or institutions at the regional level and on the global scale. We share the information about plastic pollution, try to estimate the amount, and harmonize the method.

But now, our primary concern is with waste management in Indonesia. So, to tackle this, our organization develop some policy papers and recommendations for Indonesian waste management policy.

One of our recommendations is to install the river trash boom (a netting system with floaters that blocks trash and plastic from making their way into the sea) in each river in Indonesia.

We are optimistic that this will help Indonesia to reach the Sustainable Development Goals. And hopefully, to tackle plastic debris that ends up in the ocean.

Lastly, could you tell us where you want to see the future of estimation and monitoring?

One of my dreams is to find out which areas in Indonesia emit how much debris in different months. For example, there are a lot of plastics that are stranded on the beach in the earlier months of the year in Kuta, Bali. But until today, we do not know the sources of these plastics. I want to know which area that excrete the most garbage leak, whether it is micro or macroplastics, before the debris goes to our beaches. And then, after we find these sources, we can provide data and suggest a research-based policy to local governments.

All photos are courtesy of Dr Muhammad Reza Cordova

Also read: Ocean Under Stress: The Insidious Effects of Microplastics on Our Coral Reef