Rosignano Solvay-Castiglioncello (Italy) (AFP)

Turquoise waters and white sand. "I like to come here, even if it's a little disturbing," says a retired couple, in the midst of dozens of regulars from the Italian beach of Rosignano Solvay, named after the chemical plant behind this unprecedented phenomenon.

Mercury and heavy metals that can cause serious diseases or simply limestone on the bottom of the water? This 4 km long beach, 25 km south of the Tuscan port of Livorno, raises many questions.

Located in one of the most beautiful regions of the country, it seems straight out of a Caribbean postcard.

"I found it on Google Maps, I was told it's not dangerous, the color comes from the soda plant next door, and I brought all my family," says AFP. Lieuya, a Dutch tourist, confirming that "the white beaches" of Rosignano are one of the attractions of the coast.

Dark glasses in front of a blinding light, tourists stroll on the pristine sand, without wondering about the striking contrast with the nearby beach of Monte alla Rena.

"Every time I come, I think that if the bathing is authorized by local, regional and national authorities, we can believe them when they say that the water is clean," says Marina, an Italian teacher.

Indeed, at the entrance, a sign from the regional environmental protection agency, Arpat, certifies that the quality of the water is "excellent".

Rosignano Solvay was founded more than a century ago in 1912 by the Belgian Ernest Solvay, who set up a factory there and then had houses built there. His group is now a global chemistry giant present in 61 countries and employs 24,500 people.

- "Mamma" Solvay -

"Solvay was like a mother to this area of ​​Tuscany, called + the mamma +, the city bears his name (that of the founder), and he guaranteed the well-being of a school, a hospital, a theater. The unemployment rate has always been low, "told AFP Leonardo Martinelli, a journalist for the daily La Stampa, born in this locality and whose mother worked half a century at Solvay.

In the huge brick building of the early 20th century, the management multiplies the reassuring statements, without allowing access to its laboratories.

"We respect all the standards of a high-risk site", explains to AFP Davide Papavero, industrial director of the Solvay group and boss of the plant. Solvay produces bicarbonate for industrial and food use as well as advanced materials used in high technologies (automotive, construction, electricity, water treatment).

"The plant uses a large amount of seawater for cooling equipment but only releases limestone powder and plaster, only inert materials that are safe for the environment, but that explain the white color of the plant. sand, "says Papavero.

The blue of the sea "is explained by the reverberation of the light," said this engineer, repeating that the quality of the water is controlled "by Solvay, the regional authority Arpat, the Ministry of Environment and the Higher Institute for the Protection of the Environment ".

The mayor Daniele Donati knows the factory well and also ensures that the industrial processes do not "pose any problem for the health".

Maurizio Marchi, from the Medicina Democratica association, continues a fierce fight against the factory. "The reality is that for a century, this place is a dump of Solvay, an industrial dump," he argues.

For other environmental defenders, the most shocking are the limestone hills ripped open near San Vincenzo and a massive pre-emption of rock salt that exhausts the deposits of the area.

According to experts, Marchi's battle is obsolete: "In the 1980s it was a toxic beach, but the cycle of production that used mercury and heavy metals was changed," explains Manolo Morandini, of the daily newspaper. Il Tirreno, who has written a lot on the subject.

The "white beaches" are, for him, only an "artificial place". And for holidaymakers, a corner of paradise.

© 2019 AFP