Outokumpu’s deep hole water smells-The study revealed the cause of VOCs

”Outokumpu The bedrock revealed a smelly surprise, ”says a bulletin at the University of Helsinki.

A deep hole was reached by the surprise, the Geology Research Center (GTK) drilled for scientific research in an area that became famous for its ore resources 20 years ago.

The hole reaches a depth of 2.5 kilometers and is full of water. Water samples raised from depths smell.

Sniffers have described the scent as maritime, sewer, even a little sweet, says the assistant professor of the University of Helsinki Riikka Kietäväinenwho has been responsible for geochemical research in water samples.

When Kietäväinen himself applied for a ground -based counterpart, he ended up in an Asian fish sauce, which is also sold in Finnish supermarkets.

“Not really fresh scent,” Kietäväinen says.

Samples have now been analyzed and the results have been published Communications Earth & Environment -in leaf. The cause of the smell was not just the fact that Water has been lying in Kallio for tens of millions of years.

Surprisingly, more than forty VOCs, or volatile organic compounds, were found in the waters. Substances were found in every depth between 500 and 2,300 meters.

The most common were butane, benzene and dimethyl sulphide. There were also other hydrocarbons, alcohols, ketones and aldehydes.

Many smell at very low concentrations, such as aromatic carbon water and sulfur compounds.

Monet VOCs are harmful to humans. They have not been determined by safety in the breathing air.

VOCs are created in industrial processes and can also be released into the air from various materials such as paints and corrosion inhibitors.

Due to its water solubility, VOCs are also a threat to groundwater. According to Kietäväinen, the discovery of Outokumpu reminds us how a thin layer of fresh groundwater in Finland can be.

“In a deep hole, at a depth of a few tens of meters, the water is drinkable without spoiling man. Not all natural is healthy and good. ”

In the wild VOCs are created in marshes, forests, volcanoes and hot springs.

Finding them deep in the bedrock was new and surprising, says Kietäväinen.

An essential part of the compounds is carbon. In Outokumpu’s old bedrock, it should be very low in carbon, as it was baked in 500-600 degrees Celsius with a mountain range of 1.9 billion years ago.

In heat and pressure, carbon became graphite. An even harder pressure would have squeezed diamonds from it.

Carbon -rich VOCs also found an explanation in the study. Deep biosphere microbes can produce them from low carbon.

Bacteria and fungi, in particular, play an important role as producers and decomposers of VOC compounds.

“In deep bedrock, microbes have little food and carbon sources available, and the results of the study show that these VOCs bring new opportunities to the microbial dining table,” VTT senior researcher Mari Nyyssönen says in the bulletin.

Research results may play a role in understanding carbon circulation and building underground spaces.

Microbes can affect air quality in the mine and corrosion of structures, for example, in a nuclear waste cave or in a geo -energy well.