Sharks gathering off Israel’s Mediterranean coast near the Hadera power plant may serve as real-time indicators of environmental contamination in the marine ecosystem, according to a University of Haifa study that found unusually high concentrations of industrial and rare earth elements in their blood.
Lead researcher Danny Morik told The Press Service of Israel that the findings raise new questions about the long-term impact of industrial activity, desalination plants and power stations on marine life in one of the world’s most environmentally stressed seas.
“We found heavy metals such as arsenic, mercury and lead. The levels in the sharks’ blood here were higher than levels found in sharks elsewhere in the world,” Morik told TPS-IL. “Because sharks are apex predators, they go through a process of bioaccumulation and store metals in their bodies. Sharks also live many years, so this gives us information about the environment. They serve as a bioindicator. Taking a sample from the water, with all its solubility and currents, cannot show any of it,” he added.
According to Morik, the findings in sharks could also point to the presence of these metals in smaller fish species that are commonly consumed by humans.
The study, published in the peer-reviewed Environmental Pollution, examined blood samples from 27 adult dusky sharks and sandbar sharks that gather seasonally near Hadera, where warm water discharged from the nearby power plant attracts large numbers of sharks every winter.
Researchers from the University of Haifa’s Morris Kahn Marine Research Station, together with scientists from Brazil and the Bahamas, analyzed the blood samples using advanced laboratory methods capable of identifying dozens of chemical elements at varying concentrations.
“There is a fully trained team with all the permits required to study them. We catch them, attach them to the boat, carry out various tests and swabs, and one of the tests is taking blood samples,” Morik said.
The Mediterranean Sea is one of the world’s most vulnerable marine environments due to its relatively enclosed structure, slow water exchange and dense concentration of industrial and urban activity along its coastline. Morik said these conditions can amplify the accumulation of pollutants within marine ecosystems.
The findings do not prove direct harm to the sharks, and Morik stressed that many of the detected substances also occur naturally in marine environments. However, the combination of industrial discharge, desalination activity and natural environmental processes likely contributes to how such materials accumulate and disperse in the ecosystem, he said.
Morik added that another significant find was REEs, or Rare Earth Elements, in the sharks’ blood.
“The whole world depends on these materials. These are 15 substances used in advanced industries, in solar panels, batteries and LEDs,” he said. “In the past there was less need for them; now everyone wants them. They are essential for new technologies. We still do not know whether they are toxic or not. It opens many questions.”
