A new bathing bulletin released this Thursday (22) by the Environmental Company of the State of São Paulo (Cetesb) points out that 86% of the beaches on the coast of São Paulo are suitable for swimming.
Of the 175 beaches monitored, 151 were classified as suitable and 24 as unsuitable. Between restricted points
The purpose of monitoring is to detect Enterococci — microscopic bacteria, invisible to the naked eye — which act as warning signs for fecal contamination and whose concentration determines whether the beach is considered suitable for swimming or not.
“Apparently clean water may be unsafe. Therefore, monitoring is essential to guide the population and support public management”, explains Claudia Lamparelli, manager of Cetesb’s Coastal Water Sector.
How does the assessment work?
The process is carried out every week, throughout the year. The teams collect at the same point and at a depth of approximately one meter, ensuring standardization. In the laboratory, samples are analyzed to count Enterococci. The classification follows the following technical criteria:
- Own: results within the safety standard;
- Improper: when two or more samples from the last five weeks exceed 100 colonies of Enterococci per 100 mL, or when the most recent collection exceeds 400 colonies per 100 mL.
The five-week history is used to reflect a true water quality trend, not a one-off change.
Furthermore, Cetesb reinforces that the recommendation is to avoid swimming for at least 24 hours after heavy rain, even on beaches classified as suitable. Canals, rivers and streams that flow onto the beach should also be avoided, as they may receive irregular sewage.
