A researcher from the Hebrew University found for the first time the mechanism that causes the unusual concentrations of mercury in the Dead Sea and in fish

The Dead Sea is a unique research arena for understanding the way in which active mercury is created, because it is the only place in the world where the level of active mercury is high enough to allow measurements and monitoring of it and the factors that lead to its creation

Researchers from the Hebrew University and the USA have for the first time found the mechanism responsible for the accumulation of harmful mercury in the Dead Sea and in certain types of fish in the seas and oceans.

The researchers, Prof. Menachem Luria from the Earth Research Institute at the Hebrew University and Dr. Daniel Obrist from the University of Nevada, found in their research that bromine compounds that are emitted into the atmosphere from the sea, and are emitted in particularly large quantities from the Dead Sea, create a chemical reaction with passive mercury found in the Earth's atmosphere and make it active .

The Dead Sea is a unique research arena for understanding the way in which active mercury is created, because it is the only place in the world where the level of active mercury is high enough to allow measurements and monitoring of it and the factors that lead to its creation. "All over the world, the amount of active mercury constitutes about one percent of the general amount of mercury in the atmosphere," explains Prof. Luria, "in the atmosphere over the Dead Sea, on the other hand, abnormal levels of active mercury were found up to about 50% of all the mercury in the atmosphere."

The researchers found that this phenomenon is caused by a reaction between the mercury and the bromine compounds in the air above the Dead Sea. The proportion of the bromine compound in the Dead Sea is 200 times higher than other seawater, and its evaporation is accelerated due to the high temperature in the area. According to the researchers, a similar process of mercury becoming active occurs over all the seas and oceans around the world, but at a much lower intensity.

As you know, the world's health authorities warn from time to time against eating certain fish that contain particularly high levels of harmful active mercury. However, until now the mechanism causing the phenomenon was unknown. The research revealed that in fact the active mercury that is created in the atmosphere sinks into the seas and oceans and is absorbed into the tissues of marine populations. The researchers concluded that this is the main mechanism that causes high levels of active mercury in certain fish to the point of health risks.

"No easy way has yet been found to lower the levels of mercury compounds whose main source is the burning of coal in the atmosphere. This is a problem that needs to be dealt with globally, similar to dealing with the problem of greenhouse gases," claims Prof. Luria.

The research was conducted with the support of the United States National Science Foundation (USNSF), and was recently published in the Nature Geoscience Journal. "This discovery joins other discoveries in the Dead Sea basin, which serves as a natural laboratory for the study of a long series of biological-chemical and geophysical processes," says Prof. Luria.