The Cerro Lagoon in the Paraguayan city of Limpio is sharply divided into two parts: one purple, one blue. One part emits a foul odour, the other doesn’t.
The lagoon was split by construction of an embankment and roadway to carry trucks to and from local factories.
Several months ago, people began noticing that the water had changed on one side of the roadway and that fish and birds were dying. They went to local environmental authorities who took water samples.
“Three months ago all the fish died in the lagoon, thousands and thousands of them,” said one resident, Herminia Meza. “The smell was unbearable and we were overwhelmed by flies. About a month ago the herons died and it turned a reddish color.”
Francisco Ferreira, a technician at the National University Multidisciplinary Lab who took samples, said Wednesday that the colour of the water is due to the presence of heavy metals like chromium, commonly used in the tanning of animal skins to produce leather.
The Waltrading SA tannery stands on the lagoon's banks.
“We will do the analysis (of water samples taken) and I will pass my report to the Legal Department," Rosa Morel, an inspector with the Ministry of the Environment and Sustainable Development, told local ABC media outlet. "There is a tannery and it is definitely the tannery that pollutes.”
Morel said on a previous visit experts found a pipe, presumably from the tannery, dumping untreated waste into the lagoon. She said authorities' main demand is that the company build a treatment plant for the waste.
The company has declined to speak to the media about the issue, ABC reported.