Health Risks Raise Alarm After Cisadane River Contaminated by Pesticides

Jakarta — The Cisadane River has been contaminated with pesticides following a warehouse fire belonging to PT Biotek Saranatama in South Tangerang, raising significant health risks in the aftermath.

The pesticide factory, located in the Setu sub-district of South Tangerang, caught fire on Monday (9/2/2026). Firefighters required two sand trucks to extinguish the blaze, which originated from chemical materials. The fire was only brought under control after seven hours.

The blaze not only caused material losses but also left a trail of water contamination in the Cisadane River. Large numbers of fish died after the river water was allegedly contaminated by the pesticide factory, with the water turning white following the pollution.

Minister of Environment Hanif Faisol Nurofiq called on PT Biotek Saranatama, as the owner of the chemical pesticide warehouse, to take responsibility for environmental restoration. He said the measure was taken as a firm stance by the government against environmental offenders.

“They must take responsibility because the impact is significant. Additionally, in terms of administration and technical matters, we will request the area manager to conduct a precise environmental audit to take the necessary steps,” said Hanif.

Warehouse Owner Pledges to Restore Water Quality

PT Biotek Saranatama, the pesticide warehouse owner, has pledged to restore water quality in the river channels contaminated by chemicals following the fire. The restoration involves the dispersal of pesticide adsorbents to neutralise the contamination impact.

Luki, the Operations Manager of PT Biotek Saranatama, said the water quality restoration efforts were undertaken as part of the company’s responsibility. “For the air, we are using products supplied by the Ministry of Agriculture, and for the river, we have provided pesticide adsorbents to neutralise the pesticides,” he said.

According to him, the dispersal of pesticide adsorbents in the Jeletreng River — an upstream tributary feeding into the Cisadane River — could help bind and remove pesticide residues. He said the company had coordinated with the South Tangerang Environmental Agency.

“We have also coordinated with the South Tangerang Environmental Agency to carry out neutralisation of air quality and the river,” he said.

The company is also working to restore the river ecosystem, including the release of 5,000 fish fingerlings comprising catfish, tilapia and gourami. Luki said the company would coordinate with the relevant ministry regarding the fish fingerling dispersal.

“Today we are also restoring the biota ecosystem in the river by releasing around 5,000 fish — catfish, gourami and tilapia. But the restoration of biota and ecosystems is not related to the chemicals, so we are doing that ourselves. It will be periodic. We also conduct regular water checks, and we will have a team handling that as well,” he said.

Risks of Pesticide Contamination

Ignasius Sutapa, a researcher at the Limnology and Water Resources Research Centre of the National Research and Innovation Agency (BRIN), outlined the potential impacts of pesticide contamination in the Cisadane River following the warehouse fire.

Ignas said the chemical spill could pose risks of chronic health effects. He explained there was potential for bioaccumulation and biomagnification caused by the transfer of pesticide residues or metabolites that accumulate in the tissue of aquatic organisms, then move to higher-level predators, including humans who consume fish from the river.

“This risk means the contamination does not only have short-term impacts but also has the potential to cause chronic health effects,” said Ignas.

Ignas said the contamination could also reach the river’s bottom sediment and become a source of secondary toxin release over a longer period.

Toxins May Settle in Sediment

This means that even if the surface water appears clear again, the toxic threat may still be stored in the sediment layer and could be released back into the water column under certain conditions.

From a public health perspective, Ignas continued, pesticide exposure could occur through direct contact such as bathing and washing, as well as indirectly through the consumption of raw water or contaminated fish.

He noted that certain types of pesticides, particularly neurotoxic ones, could cause acute symptoms such as nausea, dizziness, nerve damage and even death depending on the exposure dose.

“In the long term, chronic exposure has the potential to trigger endocrine disruption, organ damage and even carcinogenic risk,” Ignas said.

For short-term mitigation, he recommended the temporary closure of PDAM (regional water utility) raw water intakes in affected zones, enhanced real-time water quality monitoring, and rapid public education urging communities not to use river water for any purpose until it is declared safe. In-situ neutralisation or remediation efforts also need to be carried out if the source of contamination is still identified.

Ignas emphasised the importance of long-term strategies, ranging from strengthening oversight and law enforcement against hazardous waste polluters, developing early warning systems based on online water quality sensors, to diversifying raw water sources to enhance water resilience during crises. He said river ecosystem restoration through rehabilitation of riparian zones was also a crucial step to enhance the river’s natural capacity to filter pollutants.

“We urge the public not to panic but to remain vigilant and follow official instructions from the government and PDAM. Do not use river water for cooking, drinking, washing or bathing until a statement is issued confirming the water is safe. Avoid consuming fish from the affected area during the crisis period,” he concluded.