The Water Authority (ADA) of the province of Buenos Aires issued a health alert due to the presence of cyanobacteria in water bodies of 14 municipalities. These blue-green algae pose a health risk and are especially detected in rivers and lagoons used for recreational purposes.
- General Madariaga: the only district on red alert, with high risk in the La Larga lagoon.
- Avellaneda, Balcarce, Benito Juárez, Bragado, Chacabuco, Chascomús, Daireaux, Lezama, Lobos, Monte, Navarro, Pehuajó, and Rivadavia: on orange alert, with moderate risk.
What are cyanobacteria
They are microorganisms that proliferate in warm, nutrient-rich waters, typical of summer. As they multiply, they generate blooms that tint the water blue-green and release dangerous toxins.
These toxins can accumulate in the water and affect both people and animals that come into contact with it.
Health risks
Contact with contaminated waters can cause:
- Dermatological: irritation, rashes, conjunctivitis, and blisters.
- Gastrointestinal: vomiting, diarrhea, abdominal pain, and nausea.
- Neurological: headaches, fever, joint pain, and in severe cases, muscle contractions or paralysis.
The most vulnerable groups are children, the elderly, pregnant women, and pets, who may suffer more severe consequences.
Preventive measures
The ADA and the Subsecretariat of Water Resources recommend:
- Consult the official cyanosemaphore (gba.gob.ar/cianobacterias) to check the risk level.
- Respect the health flag: if it is placed, do not enter the water or allow children or pets to do so.
- In case of contact, wash immediately with clean water and change clothes.
- Do not consume fish from lagoons with cyanobacteria blooms.
Permanent monitoring
The province’s Environmental Health Directorate conducts controls in lagoons such as Chis Chis, Lobos, Monte, and Sauce Grande, cross-referencing municipal reports with satellite monitoring. The goal is to keep the risk map updated and protect swimmers and athletes.
This surveillance system aims to anticipate proliferation peaks and issue quick alerts to prevent the population from being exposed to contaminated waters. Coordination between municipalities and the province is key to ensuring preventive measures are timely.
Environmental context
Cyanobacteria blooms have become more frequent in recent years due to:
- High temperatures associated with climate change.
- Excess nutrients in the water from agricultural and urban activities.
- Stagnation of water bodies during drought periods.
These factors create a favorable scenario for cyanobacteria to multiply and reach dangerous levels.
The presence of cyanobacteria in Buenos Aires waters is a recurring phenomenon in summer, but its impact on health requires extreme precautions. The red alert in General Madariaga and the orange alerts in 13 other municipalities highlight the need to inform oneself before entering the water and to respect preventive measures.
