New data has shown that the Philippines accounts for one-third of the total ocean plastic globally. In a study by Lourens J. J. Meijer, Tim van Emmerik, Ruud van der Ent, Christian Schmidt, and Laurent Lebreton with the title “More than 1000 rivers account for 80% of global riverine plastic emissions into the ocean” published at ScienceAdvances on April 30, 2021. The Philippines is found to be the largest contributing country to ocean plastic waste.
The Summary of the Study
According to the study, 80% of the global ocean plastic comes from rivers and coastlines and only 20% are coming from marine sources like fleets, fishing nets, and ropes. On this premise, the study was done to determine which rivers are the highest contributor to plastic emissions into the oceans. Previous similar studies were done in 2017 and the findings were that huge rivers like the Amazon, Ganges, and the Yangtze rivers were the biggest contributors to ocean plastic pollution. However, in a recent study, it was found that small rivers play a significant role in ocean plastic pollution.
The Differences of the old and new studies
The old study relied on a simpler model taking into main consideration the waste generation the world’s river basin, the factors are based on the following:
- Amount of mismanaged waste within the world’s river basins
- The population density in the area
- Correlative models of plastic concentrations in surface rivers
These factors were then used to model the amount of pollution from basins where data on the number of river plastics is not available.
This model will yield that the biggest emitter of plastic into the world’s ocean is very large river basins with a large population and poor waste management. Rivers such as The Yangtze, Xi, and Huangpu rivers in China; the Ganges in India; Cross in Nigeria; and the Amazon in Brazil were the big rivers that topped the list.
The new study, on the other hand, improves on the basis of the old study by adding higher resolution data. Higher-resolution factors include:
- deterministic drivers of how plastic is transported using wind and precipitation patterns and river discharge data
- plus factors such as proximity of populations to the river
- distance to the ocean
- slope to the terrain
- types of land use
Rivers that contribute most to ocean plastic
According to the data gathered, the seven rivers in the Philippines are in the top 10 rivers that emit plastic into the ocean. Two are in India and one in Malaysia. Out of the 7 rivers in the Philippines, the Pasig river accounts for a 6.3% share of ocean plastics.
Characteristics of Rivers that emit the most plastic to the ocean
The study has identified the characteristics of rivers that emit the most plastic in the ocean and these are the following:
- Poor local waste management practices
- Presence of a nearby city, which means there are lots of paved surfaces that facilitate the flow of water and plastic that drains into the river.
- High precipitation rates
- Proximity to the ocean coast.
The study further identified that the Philippines contributes 36% of ocean plastic inputs. The result was said to be unsurprising because 7 of the 10 rivers considered as largest emitters of plastics to the ocean are in the Philippines and the majority of the population lives near the coast.
Factors that determine each country’s contribution to ocean plastics
- Amount of plastic a country generates
- How plastic waste is managed
- The probability that mismanaged plastic reaching river networks
While the Philippines was found to have a lower percentage of plastic generated compared to first world countries, the poor management of plastic waste along with the high probability of the plastic wastes reaching the river networks and then the ocean. The climate, terrain, land use, and distances within river basins affect the probability that mismanaged plastic waste is emitted to the ocean.1