SURABAYA RAINWATER CONTAMINATED WITH MICROPLASTICS, ECOTON Urges Residents Not to Open Their Mouths When It Rains

An Ecoton Reseacher points to fiber-typr microplastics found in
Surabaya's rainwater. The analysis was conducted at the Ecoton Microplastic
Laboratory on Friday (14/November/2025)

Findings on microplastics in the air across 18 cities in Indonesia place Surabaya in 6th position, with contamination levels reaching 12 particles per 90 cm² per 2 hours. Continuing the research on airborne microplastics, the East Java Gen Z Network Against Single-Use Plastics (Jejak), the GrowGreen community, River Warrior, and the Ecological and Wetlands Conservation Study Institute (Ecoton) conducted a study on microplastic contamination in rainwater.

The research was carried out from 11–14 November 2025 at five locations. “All sampling locations were contaminated with microplastics. This condition is alarming and will become a serious threat to public health. Therefore, we urge residents not to open their mouths or swallow rainwater, as doing so will increase microplastic contamination in the body,” said Sofi Azilan Aini. Ecoton researcher further explained that microplastic pollution must serve as a warning for Surabaya residents to stop open burning of waste, avoid dumping trash into rivers, and reduce excessive consumption of single-use plastics.

The research was conducted by placing aluminum containers, stainless-steel containers, and glass bowls with a diameter of 20–30 cm at a height of more than 1.5 meters for 1–2 hours at five locations, with results shown in the graph below.

Graphic 1 Microplastic Abudance in Surabaya rainwater Microplastic Particle
Per Liter rainwater. The Research was conducted in 7 urban villages and one
Control (Kontrol) outside the city  (11/14/2025)

From the graph above, it can be seen that the most microplastic-contaminated location is Pakis Gelora, with 356 microplastic particles (MP)/liter, followed by Tanjung Perak in second place with 309 MP/L. “The high level of microplastic pollution is influenced by environmental conditions. For example, Pakis Gelora shows a high microplastic concentration because of open waste-burning activities and its proximity to markets and main roads,” explained Alaika Rahmatullah. The coordinator of the Surabaya Microplastic Research further noted that microplastics in rainwater originate from the burning of plastic waste and road activities, such as the friction between tires and asphalt.

The research was conducted in seven urban villages and one control location outside the city.

Surabaya Rainwater Microplastics Linked to Marine Plastic Pollution

Alaika Uses a vacuum pump to separate microplastic from rainwater
(ecoton Laboratorium Friday November 14'2025)

“Burning plastic waste produces fiber-type microplastics. Previous research conducted near waste-incineration sites in Sidoarjo showed that fibers dominate the microplastics present in the air around burning areas,” said Sofi Azilan Aini. She further explained that the microplastic study on Surabaya rainwater showed that the most common type found was fiber. “Only two types of microplastics were found in Surabaya’s air: fiber and filament types,” Sofi concluded.

The main sources of microplastics include:

1. Burning of plastic waste
2. Friction between vehicle tires and road asphalt
3. Laundry activities, including washing and drying clothes
4. Accumulated plastic waste
5. Industrial pollution
6. Exhaust emissions from motor vehicles

“Another factor contributing to microplastics in Surabaya’s rainwater is marine plastic pollution. In the water cycle, seawater evaporates into water vapor and condenses into clouds. Therefore, the higher the level of plastic or microplastic pollution in seawater, the greater the microplastic contamination in rainwater,” said Ridha Fadhillah.

Recommendations

1. Stop open burning of waste
2. Stop dumping plastic waste into rivers and coastal areas
3. Stop using single-use plastics
4. Impose public exposure or social sanctions, such as displaying photos of residents who burn plastic waste or dump plastic into rivers or coastal zones
5. Conduct regular microplastic monitoring of Surabaya’s air quality