Researchers thought it only happened at the poles; new research between Israel and the US shows that bromine above the sea can make mercury way more toxic in fish.
A joint US/Israel study funded by the National Science Foundation has found that the Dead Sea has measurable effects on the chemistry of the air above it, in a paper just published at Nature: Geoscience.
The research, led by scientist Daniel Obrist and colleagues at Nevada’s Desert Research Institute with a group of Israeli researchers at Hebrew University, found that mercury was concentrated into the most toxic form in the air above the Dead Sea.
The atmosphere over the Dead Sea, researchers found, is laden with oxidized mercury, a much more toxic form of Mercury than the elemental form. The finding was surprising, as such high levels of oxidized mercury have only been found at the polar regions.
“We’ve found near-complete depletion of elemental mercury – and formation of some of the highest oxidized mercury levels ever seen – above the Dead Sea, a place where temperatures reach 45 degrees Celsius,” Obrist noted.
The findings are a concern because oxidized mercury threatens the food supply more readily than the elemental form. That is because, once oxidized in what scientists call elemental mercury depletion events – it is then readily deposited on a surface such as the ocean, and can then find its way into the food chain.
This happens in polar regions and is a concern because these mercury depletion events increase mercury loads to sensitive arctic environments by hundreds of tons of mercury each year. But it was not thought to convert so readily in warm regions.
The researchers found that the high levels of Bromine in the Dead Sea that was responsible for the conversion of mercury to the dangerous oxidized form.
“Elemental mercury is somewhat resistant to oxidation, so it’s been difficult to explain levels of oxidized mercury measured in the atmosphere outside polar regions,” says Alex Pszenny, director of the Atmospheric Chemistry Program of the National Science Foundation. “These new results provide an explanation.”
The study is interesting because the two groups of researchers share similarities. While the study was carried out at the Dead Sea, Nevada’s Great Salt Lake has similarities with the Dead Sea. Both are internal seas with no outflow to the ocean, both are in hot desert climates, and both are very salty seas that evaporate in the great heat to further concentrate their chemistry.
More on the Dead Sea:
Irony at the Dead Sea, Too Much Water at the Southern Portion
Palestinians Support Dead Sea for Wonder of the World
Unprecedented Climate Change Research Rig Starts Drilling At Dead Sea
Image: Marina Bond
Was a study performed on Nevada’s lake? Did it also have concentrated oxidized mercury in the air?
Does this make it dangerous for people to swim there?