NAIROBI, Kenya — The Kenya Wildlife Service (KWS) has raised alarm over a suspected chemical discharge flowing into Nairobi National Park through the upper Mlolongo drainage corridor, triggering fears of severe environmental contamination and threats to wildlife.
In a statement issued on Thursday, KWS said officers on patrol discovered abnormal inflows entering the park and the Athi Dam ecosystem.
“Officers on patrol observed abnormal inflows entering the park, characterised by white, effervescent bubbles, continuous flow and unnatural colouration consistent with possible chemical contamination,” the agency said.
The suspected pollution was first reported on the morning of April 30, prompting an immediate response from wildlife and environmental authorities.
Preliminary investigations indicate the runoff may have interacted with nearby industrial zones bordering the park, with KWS identifying areas near Orbit Chemical Industries Ltd as a possible source. However, the agency stressed that investigations are ongoing and no company has yet been formally held responsible.
Orbit Chemical Industries, founded in 1972 along the Mombasa-Athi River Road corridor, manufactures industrial and household chemical products, including sulphonic acid, sulphuric acid, and sodium lauryl ether sulphate.
The dam supports aquatic life, including hippos and crocodiles, and serves as a critical watering point for rhinos, lions, cheetahs, hartebeests, and waterbucks, particularly during dry seasons when water becomes scarce.
Conservationists warn that contamination of the water system could poison aquatic organisms, disrupt biodiversity, and threaten the wider ecosystem of the park.
KWS further warned that the contamination threat extends beyond the park boundaries because the affected drainage system connects to the Mbagathi and Athi rivers, potentially exposing downstream communities, livestock, and agricultural activities to health and environmental risks.
The Athi River basin has repeatedly been cited by parliamentary committees and environmental researchers as one of Kenya’s most polluted river systems due to industrial discharge, sewage, and agricultural runoff.
In response to the latest incident, KWS said it had activated a multi-agency intervention involving the National Environment Management Authority (NEMA) and the Water Resources Authority (WRA).
“We are conducting water sampling and laboratory analysis in collaboration with NEMA and WRA. Officers are also tracing upstream discharge points and evaluating containment measures to prevent further contamination,” the statement said.
The public has been advised to avoid contact with affected water bodies and refrain from fishing or using water from contaminated sections.
KWS said wildlife veterinarians and game wardens would closely monitor animals around Athi Dam in the coming days to assess any signs of poisoning or distress linked to the suspected contamination.
Established in 1946, Nairobi National Park is Kenya’s oldest national park and remains the only national park located within a capital city globally.
The 117-square-kilometre protected area plays a key role in biodiversity conservation, tourism, and ecosystem protection within the Nairobi metropolitan region.
KWS also warned industries operating within the catchment area against illegal discharge of untreated waste into rivers and protected ecosystems, saying violators risk prosecution, fines, closure of facilities, and liability for environmental restoration.
