Freshwater Arctic Fish in Russia Have Lower Mercury Levels than Expected

The economic downturn that fell upon the former Soviet Union in the 1990s may have had unexpected benefits for fish in Russian waters, according to a new study.

Atmospheric mercury, which enters ecosystems through industrial processes such as mining and ore smelting, is high in fish found in North American and European Arctic waters. It was presumed that fish in all Arctic waters would have similarly high mercury levels, but it turns out that is not the case, according to a new report in the journal Environmental Science and Technology.

Fish swimming in Russian Arctic waters have much lower mercury concentrations than expected, when compared to fish in North American and European Arctic waters.

"It turns out that the economic decline of the former Soviet Union, which collapsed in 1991, appears to have been good for the Arctic environment in that part of the world," said Leandro Castello, an assistant professor of fish and wildlife conservation in the College of Natural Resources and Environment at Virginia Tech.

Castello and his colleagues studied burbot, a cod-like fish found in fresh waters throughout the Arctic. Non-migratory burbot are long-lived and eat other fish, making them good candidates for measuring local mercury concentrations.

"The burbot fish was chosen because they are top predators that integrate many bio-geo-chemical processes in the river watersheds," said Castello. "The fish were collected downstream of the watersheds, so that they would present everything that happened upstream."

Alexander V. Zhulidov, of the South Russian Centre for Preparation and Implementation of International Projects, was a co-author of the research.

"We developed and led an initiative of biological monitoring of the water quality of major rivers of Russia in 1980 and continued to do it until 2001, because we knew it could provide useful information one day. In 2002 the funding was cut and the program was closed. Unfortunately we have no funding to continue collecting such interesting data," said Zhulidov.

Burbot sampled from the Mezen and Lena rivers tested for lower mercury concentrations, which the researchers said correlated with the economic collapse in the region. Burbot sampled in other regions around the world that did not experience a similar economic collapse had higher concentrations of mercury.

The researchers suggest further study of Russian Arctic ecosystems will provide a better understanding of how mercury moves through the environment.