Untreated Gaza sewage suspected in algae bloom that halted most Israeli desalination plants
Scientists are investigating whether wastewater discharged from Gaza contributed to a large algae bloom that forced the temporary shutdown of five of Israel's six major desalination facilities.
A massive algae bloom spreading along Israel's Mediterranean coast forced the temporary closure of five of the country's six major seawater desalination plants, which supply about two-thirds of Israel's drinking water. The bloom was first reported by the national water company Mekorot, which said the plants at Ashkelon, Ashdod, Palmachim, Sorek A and Sorek B were taken offline.
Mekorot spokesperson Lior Gutman described the incident as unprecedented in Israel. The water authority responded by increasing supplies from the Sea of Galilee, groundwater wells and reservoirs while limiting some irrigation uses.
Researchers are examining several possible causes. Avner Gross, head of Ben-Gurion University's Climate Change Laboratory, noted that Gaza's wastewater infrastructure has been heavily damaged in the conflict, with estimates of up to 40,000 cubic metres of untreated sewage entering the sea each day. He said satellite images show similar algae growth near Egypt's Nile Delta, where agricultural runoff adds phosphorus and nitrogen to the water.
"In our case, I currently have no other explanation except a pollution source in the southern Gaza Strip," Gross told Ynet.
Environmental group Zalul's chief executive Noga Armi also said untreated Gaza sewage was a contributing factor, while marine ecologist Tamar Guy-Haim cautioned that the likelihood of it being the primary driver is relatively low. The bloom has been identified as a cyanobacterium of the genus Synechococcus, though the exact species and trigger remain under study.
Scientists cited warm Mediterranean temperatures, strong sunlight, ocean currents and a recent storm that increased water turbidity as additional factors. Or Bialik of the Israel Oceanographic and Limnological Research institute said the water appeared unusually green and turbid, limiting visibility of instruments.
Edo Bar-Zeev of Ben-Gurion University warned that similar events could become more common as regional sea temperatures rise.
The investigation continues, with experts considering a combination of climate-related warming, natural currents, regional pollution and the influx of untreated sewage as possible contributors to the unprecedented bloom.