Lake in Argentina turns shocking pink; here's why

The compound flows into the lagoon from the Chubut river, where numerous fish factories have been set up upriver in Trelew. According to Argentinian law, the effluent must be treated before being dumped into water bodies. Locals in the nearby settlement of Rawson have been complaining of pollution and blocked the roads for trucks carrying processed fish waste to the water treatment facility on the edge of the town.

Pablo Lada, an environmental activist, said, "We get dozens of trucks daily, the residents are getting tired of it."

The provincial authorities reportedly allowed the trucks to dump the untreated waste into the river and lagoon due to the protests.

The authorities are looking to minimise the environmental impact of the incident.

"The reddish colour does not cause damage and will disappear in a few days," Juan Micheloud, the environmental control chief for Chubut, told AFP.

The head of the Rawson Environmental Sociedad Anónima (RASA), the organisation responsible for the handling effluent, said the bright pink colour was not due to any contamination but due to a lack of oxygen, in a local radio interview. He added that RASA was not responsible for the lagoon’s unusual appearance.

However, activists and residents do not share that opinion.

"It is not possible to minimise something so serious," said Sebastian de la Vallina, planning secretary for the city of Trelew.

"Those who should be in control are the ones who authorise the poisoning of people," Lada added to AFP.

While the fishing industry provides plenty of jobs to the 600,000 residents of the Chubut province, locals often suffer due to the effluent discharged by the factories.

"Fish processing generates work... it's true. But these are multi-million-dollar profit companies that don't want to pay freight to take the waste to a treatment plant that already exists in Puerto Madryn, 35 miles away, or build a plant closer," said Lada.