BEAUFORT DELTA - Much of the mercury affecting marine life in the Arctic Ocean comes from the Mackenzie River, researchers have found.

A team of researchers from the University of Alberta and Simon Fraser University collected samples from the river over three months in 2004 that showed the amount of mercury in the river over that time was the same as the annual amount of mercury thought to flow from the river into the ocean, as published in previous studies.

Mercury continues to be a concern in the NWT. A new study shows the Mackenzie River is a major exporter of the toxic metal. Back In February Environment Canada said it had found increased levels of mercury in NWT caribou. - NNSL file photo

Those studies took short-term data and tried to extrapolate it over a year, whereas this research team was able to examine mercury in the river more closely.

The Science of the Total Environment Journal published their study in April. Two weeks ago, members of the team returned from a month-long trip to the Beaufort Delta region after collecting more data for further research.

Mercury has toxic effects on humans' nervous systems and high quantities of it can cause developmental deficiencies in unborn babies.

Jennifer Graydon, a University of Alberta post-doctoral fellow in biological sciences who is part of the research team, said concentrations of mercury in the Mackenzie "aren't alarmingly high."

"They're relatively not that high compared to, say, a contaminated site, but when you look at how much water and how many particles that river exports, it's a large source of mercury, of total mercury and methylmercury, to the Beaufort, which has implications once you start looking at food webs and things there," she said.

The concentration of mercury increases in animals when it is passed on through the food chain.

The study provides a clearer understanding of how much mercury is exported to the Arctic Ocean, but Graydon said the information they've collected so far is just an "initial glimpse."

"Mercury in the Arctic is a general concern because of its biomagnification through food webs to those top predators, so this was our attempt to put a few more pieces of the puzzle together for where the mercury sources are in the Arctic Ocean, and to better characterize inputs from rivers or at least try to start to."

As for how mercury gets into the Mackenzie River, a study currently undergoing peer review written by Jesse Carrie at the University of Manitoba suggests mineral soils from the Mackenzie Mountains may have been releasing mercury into the water since the Ice Age.

The next step for Graydon's team will be looking at ice jams in the Arctic and how the chemical make-up of nearby lakes change when water floods into them every spring.