Surabaya, November 2025 — Surabaya, November 2025 — A recent study led by the Ecological Observation and Wetlands Conservation (Ecoton) Foundation reveals that rainwater across all monitoring sites in Surabaya is contaminated with microplastics. This finding reinforces earlier reports on airborne microplastics in 18 cities across Indonesia, which ranked Surabaya sixth with a contamination level of 12 particles per 9 cm² per 2 hours.
This follow-up research on microplastics in rainwater was conducted on 11–14 November 2025 by Ecoton in collaboration with the East Java Gen Z Network Against Single-Use Plastics (Jejak), the GrowGreen Community, and River Warrior. Samples were collected at five locations across Surabaya using aluminum trays, stainless steel containers, and glass bowls with diameters of 20–30 cm, placed more than 1.5 meters above the ground for 1–2 hours.
“All sampling locations showed microplastic contamination. This is alarming and could pose a serious threat to public health. We urge residents not to consume rainwater directly, as doing so may increase microplastic exposure in the body,” said Shofiyah, GrowGreen researcher and Unesa student.
She added that this pollution should serve as a strong warning for Surabaya residents to reduce open waste burning, stop disposing of trash into rivers, and limit the use of single-use plastics.
Highest Contamination Levels: Pakis Gelora and Tanjung Perak
The study found that the highest concentration of microplastics was recorded in Pakis Gelora, with 356 microplastic particles (MP) per liter, followed by Tanjung Perak with 309 MP/L.
“The high contamination level in Pakis Gelora is influenced by open waste burning activities as well as the area’s proximity to markets and main roads,”explained Alaika Rahmatullah, Coordinator of the Surabaya Microplastic Research Team at Ecoton.
He emphasized that microplastics found in rainwater largely originate from the burning of plastic waste, friction between vehicle tires and asphalt, and the degradation of plastic waste in urban environments.
Fiber Dominant in Surabaya Rainwater Samples
The study found that the most dominant type of microplastic was fiber. “Only two types of microplastics were identified, and fibers were found to be significantly dominant,” said Sofi Azilan Aini, an Ecoton researcher.
These findings are consistent with previous research in Sidoarjo, which showed that areas near waste-burning sites produce large amounts of fiber-type microplastics.
Rainwater Contaminated by Polluted Seas
Ecoton researcher Ridha Fadhillah explained that microplastics in rainwater can also originate from the ocean. In the hydrological cycle, water vapor from microplastic-polluted seas can rise through evaporation and then condense into clouds. “The higher the level of microplastic pollution in the ocean, the greater the likelihood that microplastics are carried into the atmosphere and fall along with rainwater,” he said.
Main Sources of Microplastics in Surabaya
- Open burning of plastic waste
- Friction between vehicle tires and asphalt
- Laundry activities (washing and drying clothes)
- Piles and leakage of plastic waste
- Industrial emissions
- Motor vehicle exhaust
Recommendations from Ecoton and Community Networks
- Stop open burning of plastic waste
- Stop discarding plastic waste into rivers and coastal areas
- Reduce and eliminate the use of single-use plastics
- Implement public disclosure and social sanctions for individuals who burn or dump plastic waste
- Conduct routine microplastic monitoring of air and rainwater in Surabaya
Ecoton (Ecological Observation and Wetlands Conservation) is a foundation focused on the conservation of river ecosystems and wetlands in Indonesia. We conduct scientific research, environmental education, and awareness campaigns to improve water quality and protect biodiversity.
