Seawater can no longer be suitable for bathing for different reasons, almost always linked to the entry of contaminated waste into the marine ecosystem. In Portugal, two episodes in August, one in Nazareth and one in the Algarve, showed how bacteria can reach the bathing areas and force the authorities to erect red flags.
According to the observer newspaper, in Nazaré the interdiction occurred after a technical failure at a wastewater treatment plant (WWTP), which led to the discharge of unlocked water. Already in the Algarve, the specific cause was not confirmed, but the laboratory tests revealed very high levels of Enterococcus at Praia Verde and Alagoa Beach.
Human failures and natural phenomena
According to the same source, mechanical damage in the WWTP are one of the most common reasons for the presence of bacteria such as They exhibited chill and Enterococcus in the water. These stations receive and treat wastewater, preventing pollutants from reaching the sea. When a failure, part or all water occurs can be released without proper treatment.
Adds the publication that phenomena, such as precipitation peaks, may also be at the source of the problem. Intense rain can overload the sanitation systems and lead to the flow of rainwater mixed with waste to the sea.
Improper discharges and other sources
The discharges of vessels near the coast are another factor to consider. A simple wastewater eviction of a ship can introduce fecal matter into the sea, creating a favorable environment for the development of harmful bacteria.
According to the presence of animals in water or waste that reach the sea through chains or floods can also contribute to contamination. Even on a smaller scale, these factors may be enough for water quality tests to exceed safety limits.
Detection and recovery time
The newspaper explains that the detection of bacteria is done through periodic laboratory analysis, intensified in summer due to the greater influx of bathers. Bacteria can also be suspected from visual signs such as water color change, or olfactory, as a bad smell.
There is no chemical method to “clean” water. Recovery depends on the natural movement of the sea, which disperses pollutants until the levels return to safe values. This process may take a few hours or several days, depending on the dimension of contamination and weather conditions.
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