High levels of mercury in fish has been a concern for many years now. While eating fish is considered healthy, the effects of mercury – a metal which accumulates in the body – are not and can include damage to the nervous system and liver functions.
Yet the exact cause for high levels of mercury in fish are still unclear. For years scientists thought the mercury could come from fish swimming in water near industrial plants. But a new research by Professor Menahem Luria from the Institute of Earth Science in the Hebrew University in Jerusalem and in cooperation with the University of Nevada tells a different story. According to them, the mercury polluting the water actually comes from the air, through coal burning power stations, when large amounts of mercury are released into the atmosphere.
“Mercury, in its elementary form is not dangerous,” Luria, whose research was published in Nature Geoscience Journal, told Israel’s NRG. “The problem begins when it merges with another chemical, then it becomes highly toxic. In the air above the water concentrations there are high concentration of bromine compounds, when a reaction is created between the mercury and the bromine, a heavy compound is formed which sinks into the water and the fish drink it,” Luria previously explained.
The research was conducted in the Dead Sea area, where concentrations of bromine are about 200 times higher than elsewhere.“The mercury accumulates in the fishes’ tissue and from there it is passed on to us. The older the fish is, the higher the chances are that it accumulated large quantities of mercury in its body.” That is why health authorities recommend limiting intake of older fish, like Tuna.
Photo by Jason Bagley