It wasn't just escherichia coli that caused a kilometer and a half of Poetto to be "closed" on Friday, where from the Marino hospital to the Ottagono (excluding the plant), for two days, you couldn't even soak your feet. "Fecal contamination", was the verdict of the tests. Also exceeding the limit was "the concentration of intestinal enterococci", explains Nicoletta Ornano, general director of Arpas.

" Absence of wind and great heat are climatic conditions that favor the proliferation of these microorganisms," emphasizes Sofia Cosentino, professor of Hygiene at the University of Cagliari, in the Department of Medical Sciences and Public Health. This means that "contamination is a repeatable phenomenon," the two experts agree.

The hypothesis

Therefore, the exposure of the Sardinian sea to the risk of new pollution from fecal bacteria seems destined to become a habitual condition, in times of over-tourism and bad environmental habits. "The way in which, over the course of three days, the values of escherichia coli and intestinal enterococci returned to normal - continues Ornano - leads us to think that the polluting source was not fixed, like a sewer pipe, even an illegal one. Presumably the contamination was caused by the waste released by the boats".

Values and circumstances

Escherichia coli is a cause for alarm when the mpn, the method used to measure the bacterial load, exceeds 500 in 100 milliliters taken from the sea. With intestinal enterococci the maximum limit drops to 200 mpn. "To exceed 500 and 200 means that there was a lot of waste present (and discharged) in front of Poetto," explains Cosentino.