After serious fecal contamination was recorded at the end of July, samples taken over the weekend have shown normal sea quality. The latest sample is being analyzed in Dubrovnik.
Following the microbiological contamination that led to a recommendation to ban swimming at Bili Žal beach in Lumbarda on July 30, 2026, the sea is once again safe for swimming. This was confirmed for the JUGInfo portal by Dolores Grilec, BSc in chemistry, head of the Environmental Department at the Public Health Institute of the Dubrovnik-Neretva County, after the results of samples taken over the weekend arrived.
"A colleague took samples on both Saturday and Sunday. Both results are normal. A new sample was also taken today and is on its way to the laboratory in Dubrovnik for analysis. The results will be published on the Institute's official website as soon as they are ready," Grilec stated on Monday, August 3, 2026.
Although the sea has been clean for days, the warning is not lifted automatically. Regulations require repeated sampling and laboratory analyses to confirm with certainty that bacterial levels have returned to within permissible limits. Only after consecutive results confirm satisfactory quality is the contamination officially declared over and the warning lifted on the system's website.
Grilec explains that analyzing Escherichia coli requires 24 hours of incubation, while results for intestinal enterococci are obtained after 48 hours. If the latest sample, taken on Monday, also comes back normal, the short-term contamination warning is expected to be lifted on Wednesday, August 5, 2026.
The initial finding from late July showed extremely high concentrations of fecal bacteria. The limit value for E. coli is 300 bacteria, and for intestinal enterococci 200, while the values at Bili Žal were measured in the thousands. Consequently, the Institute immediately conducted additional sampling at three locations, although routine samples are taken at one or two.
"The sea across the entire area must be of satisfactory quality. It doesn't matter whether the sample is taken a few meters left or right of the sampling point. When we're talking about such high concentrations of bacteria, such small distances don't change the overall picture," Grilec explained.
Despite the alarming numbers, the department head warns that health risks cannot be assessed solely based on them. "Any microbiological contamination can pose a risk. Whether someone develops health issues depends on a range of factors: the person's immune status, how they swim, whether there's an open wound, or if water gets into the eyes or ears. That's why we don't want to cause additional alarm by just releasing the numbers," she emphasized.
The official cause of the contamination is still being determined, but the expert assumption points to a local, one-time source of fecal water. "Since we no longer recorded elevated bacterial concentrations by Saturday, I assume there was a one-time discharge, for example from a black or septic tank. However, this is an expert assumption, not an officially established cause," Grilec noted.
It is unlikely that the contamination came from cruise ships or other vessels. "The sea has a very high dilution factor. Values like the ones we measured here most often indicate a source in the immediate coastal area, i.e., local seepage or discharge. I should remind you that samples taken on July 2 and 16 showed normal sea quality. Whether this is the same source or a different one-time discharge is something we cannot say with certainty at this point," Grilec concluded for JUGInfo.
