Plastic waste originating from Indonesia can easily travel its way through the nation's rivers and into the Indian Ocean, ending up as far as the south of Africa within a year. This shows the study of where our plastic waste ends up and how it got there is a key element in the battle against maritime pollution.
Dr Muhammad Reza Cordova's strong research interest in marine pollution, ecotoxicology, and environmental stress led him to contribute to a study on plastic pollution in the Indonesian marine ecosystem. His long experience as a researcher at the Research Centre for Oceanography at the Jakarta-based National Research and Innovation Agency (BRIN) has seen him delve into the distribution, temporal and seasonal variations, dynamics, associations with other types of pollutants and their impacts, and solutions to the marine litter problem.
Our team recently spoke with him about his expertise in monitoring and estimating plastic leakage, also known as the plastic footprint, whereby he tracks the plastic pathways from our landfills into the sea – from plastic production to its end cycle when it has become waste. He also estimates how much of our plastic ends up in the ocean and beyond.
Since 2015, I have been interested in studying marine plastic pollution. When I am in 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 in the water or the sediment. Finally, I also research its impact on marine biota if they ingest these particles.
Satellites can only detect plastic on the surface of the water, but not plastic 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 sinking marine plastic.
The 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 originate from varied pathways, which also depend on local characteristics. For example, population densities, GDP (gross domestic product), cultural habits, and the effectiveness of the local infrastructure are among the variables we monitor that contribute to plastic leakage.
Landfills are 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 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 passing into the river.
Leachate water is the water that leaks from 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 leachate water outlet pipes 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.
There is no available methodology on how plastic pollution monitoring research must be carried out. Therefore, there needs to be a harmonised method. Several guidelines in monitoring plastic litter exist in UNEP (United Nations Environment Programme), 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 cannot 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 debris movement. When we try to peer review their findings, the various adopted methodologies to estimate plastic leakage make this work difficult.
Method harmonisation makes 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.
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 toward the Indian Ocean, because the ocean current will bring all the water mass from the eastern part to the west.
Plastic litter does not have passports, so we know it can cross the border with ease. But before it crosses the border, it impacts the local areas first. So, for instance, 60% of the debris from Jakarta Bay is 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 Maritime Affairs and Fisheries deployed 10 drifters from Cisadane River. Three of them got stranded in the Seribu Islands, and three others ended up in Jakarta and north of Java. One found its way to Lampung, another 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 causes 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 where the coral reef triangle exists. Imagine if our corals interact with the local debris on top of the trash from surrounding regions – this becomes a threat to our marine biodiversity.
The theoretical framework and the pathway are clear. But the problem is, again, the supporting data. The data variables 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.
Now we are calibrating with other organisations or institutions at the regional level and on the global scale. We share the information about plastic pollution, try to estimate the amount, and harmonise the method.
But now, our primary concern is with waste management in Indonesia. So, to tackle this, our organisation has developed 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 this will help Indonesia achieve the (United Nations') Sustainable Development Goals. And hopefully, to tackle plastic debris which ends up in the ocean.
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 stranded on the beach in the earlier months of the year in Kuta, Bali. But we do not know the sources of these plastics. I want to know which area excretes the most garbage leaks, 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
Researcher at the Research Centre for Oceanography, the Indonesian National Research and Innovation Agency (BRIN)
Plastic waste originating from Indonesia can easily travel its way through the nation's rivers and into the Indian Ocean, ending up as far as the south of Africa within a year. This shows the study of where our plastic waste ends up and how it got there is a key element in the battle against maritime pollution.
Dr Muhammad Reza Cordova's strong research interest in marine pollution, ecotoxicology, and environmental stress led him to contribute to a study on plastic pollution in the Indonesian marine ecosystem. His long experience as a researcher at the Research Centre for Oceanography at the Jakarta-based National Research and Innovation Agency (BRIN) has seen him delve into the distribution, temporal and seasonal variations, dynamics, associations with other types of pollutants and their impacts, and solutions to the marine litter problem.
Our team recently spoke with him about his expertise in monitoring and estimating plastic leakage, also known as the plastic footprint, whereby he tracks the plastic pathways from our landfills into the sea – from plastic production to its end cycle when it has become waste. He also estimates how much of our plastic ends up in the ocean and beyond.
Since 2015, I have been interested in studying marine plastic pollution. When I am in 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 in the water or the sediment. Finally, I also research its impact on marine biota if they ingest these particles.
Satellites can only detect plastic on the surface of the water, but not plastic 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 sinking marine plastic.
The 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 originate from varied pathways, which also depend on local characteristics. For example, population densities, GDP (gross domestic product), cultural habits, and the effectiveness of the local infrastructure are among the variables we monitor that contribute to plastic leakage.
Landfills are 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 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 passing into the river.
Leachate water is the water that leaks from 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 leachate water outlet pipes 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.
There is no available methodology on how plastic pollution monitoring research must be carried out. Therefore, there needs to be a harmonised method. Several guidelines in monitoring plastic litter exist in UNEP (United Nations Environment Programme), 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 cannot 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 debris movement. When we try to peer review their findings, the various adopted methodologies to estimate plastic leakage make this work difficult.
Method harmonisation makes 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.
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 toward the Indian Ocean, because the ocean current will bring all the water mass from the eastern part to the west.
Plastic litter does not have passports, so we know it can cross the border with ease. But before it crosses the border, it impacts the local areas first. So, for instance, 60% of the debris from Jakarta Bay is 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 Maritime Affairs and Fisheries deployed 10 drifters from Cisadane River. Three of them got stranded in the Seribu Islands, and three others ended up in Jakarta and north of Java. One found its way to Lampung, another 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 causes 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 where the coral reef triangle exists. Imagine if our corals interact with the local debris on top of the trash from surrounding regions – this becomes a threat to our marine biodiversity.
The theoretical framework and the pathway are clear. But the problem is, again, the supporting data. The data variables 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.
Now we are calibrating with other organisations or institutions at the regional level and on the global scale. We share the information about plastic pollution, try to estimate the amount, and harmonise the method.
But now, our primary concern is with waste management in Indonesia. So, to tackle this, our organisation has developed 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 this will help Indonesia achieve the (United Nations') Sustainable Development Goals. And hopefully, to tackle plastic debris which ends up in the ocean.
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 stranded on the beach in the earlier months of the year in Kuta, Bali. But we do not know the sources of these plastics. I want to know which area excretes the most garbage leaks, 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
Researcher at the Research Centre for Oceanography, the Indonesian National Research and Innovation Agency (BRIN)
