Arctic springtime depletion of mercury

The Arctic ecosystem is showing increasing evidence of contamination by persistent, toxic substances, including metals such as mercury, that accumulate in organisms. In January 1995, we began continuous surface-level measurements of total gaseous mercury in the air at Alert, Northwest Territories, Canada (82.5° N, 62.5° W). Here we show that, during the spring (April to early June) of 1995, there were frequent episodic depletions in mercury vapour concentrations, strongly resembling depletions of ozone in Arctic surface air, during the three-month period following polar sunrise (which occurs in March),.