Schiedek, D., Asmund, G., Johansen, P., Rigét, F., Johansen, K., Strand J., & Mølvig, S. 2009: Environmental monitoring at the former lead-zinc mine in Maarmorilik, Northwest Greenland, in 2008. National Environmental Research Institute, Aarhus University. 70. pp. – NERI Technical Report no. 737.
From 1973 to 1990 lead and zinc ore was mined at Maarmorilik in the municipality of Uummannaq by the mining company Greenex A/S. The ore was primarily found in the mountain called “Black Angel”. It was mined at an altitude of about 600 metres above sea level and transported in cable cars across the Affarlikassaa fjord to a processing plant in Maarmorilik. The produced lead and a zinc concentrate was loaded on ships and transported to smelters in Europe.
During mining different sources of pollution were identified. Ore crushing and transport of concentrate created dust that was dispersed into the environment. Waste rock dumps were another source for dust but also for the release of lead and zinc to the aquatic environment (e.g. the surrounding fjords). The most important pollutant source, however, were the mine tailings that were discharged into the Affarlikassaa fjord and settled there. In addition, after mine closure, a waste rock dump was excavated and dumped into the Affarlikassaa Fjord on top of the tailings.
Since 1972, environmental studies have been conducted in the vicinity of the mine and the fjords around Maarmorilik by monitoring lead and zinc content in seawater, sediments and biota (seaweed, mussels, fish, prawns and lichens). This report presents and assesses the results of the environmental studies conducted in 2008 as well as temporal trends based on the data collected since 1972.
The lead and zinc dispersal with dust around Maarmorilik has been monitored using the lichen Cetraria nivalis. It is a good indicator for dispersal of metals in the atmosphere, since it takes up water, nutrients and contaminants solely via its surface. Lichens, transplanted in 2007 from a reference site to locations near Maarmorilik showed in 2008 increased levels of lead and zinc. Clearly elevated lead concentrations were found in lichens from Affarlikassaa, Qaamarujuk and Qeqertanguit with levels between about 2 to 10 ?g/g dry weight above background. Zinc concentrations were not elevated to as high levels as lead and were elevated only within a short distance from Maarmorilik. There is no indication that dusting with lead and zinc has changed since 1996, when we introduced a study to evaluate temporal changes.
During mine operation, lead and zinc concentrations in the Affarlikassaa fjord were high, particularly in the bottom water, mainly due to the discharged tailings. After mine closure, metal concentrations in the water have declined significantly. Since 1995, lead concentration has been about 1000 times lower than in 1988-89 during mining. This was also the case in 2008. Zinc concentrations have also decreased but to a lower degree and were in 2008 only about 8 times lower than in 1988-1989.
Seaweeds (Fucus vesiculosus and Fucus distichus) are common in the tidal zone and known to take up metals from the surrounding water and to be a good indicator of metal pollution. Seaweeds have been monitored since 1981 and their lead and zinc concentrations have decreased significantly, especially after mine closure (lead more than zinc). However, in 2008 lead and zinc concentrations are still elevated in seaweed from Affarlikassaa, Qaamarujuk and the northern coast of Perlerfiup kangerlua.
Blue mussels are suited to monitor metal pollution since they take up and accumulate metals from seawater, sediments and organic particles. Lead and zinc concentrations in blue mussels have declined significantly after mine closure, but lead levels only slowly, because the mussels cannot eliminate all the lead accumulated in the tissues. In 2008 lead concentrations were elevated in all of the studied fjords: Affarlikassaa, Qaamarujuk and Perlerfiup kangerlua. Zinc concentrations were elevated in a smaller area. Until 2005 the lead concentration in blue mussels was so high, that people were advised not to collect and eat blue mussels from these fjords. Studies conducted since 2005 show that the lead contamination of blue mussels has declined significantly, and the area with restrictions has been narrowed down to Affarlikassaa, Qaamarujuk and the area west of here.
Shorthorn sculpin (Myoxocephalus scorpius) is a common, rather stationary fish species, and therefore suited as indicator of metal contamination in fish. In both liver and bone tissue the lead concentration has decreased over the monitoring period. In 2008, lead concentrations were not elevated in muscle tissue compared to the reference site. Generally, concentrations are decreasing towards levels close to those found at the reference station, but they are still elevated (c. by factor of about 2).
Northern shrimp (Pandalus borealis) is another useful indicator to assess spatial and temporal trends of lead contamination. Over the monitoring period, lead concentrations have decreased in shrimps (head, shells and meat). In 2008, lead concentrations were slightly elevated.
The elevated lead concentrations found in the fjords at Maarmorilik have been a cause of concern for public health, when people consume fish and other biota, but except for blue mussels as mentioned above lead concentrations in 2008 were below guidelines set to protect human health.
The environmental studies conducted in 2008 document that the fjords at Maarmorilik are still affected by pollution 18 years after mine closure. However, over a number of years lead and zinc levels in seawater and biota have decreased, in particular after the mine closed, and the area affected by pollution with lead and zinc has become smaller and smaller over the years. Now an impact can be seen primarily in the Affarlikassaa and Qaamarujuk fjords.
Tailings and waste rock deposited on the bottom of the Affarlikassaa fjord are still a source of zinc release to the bottom water of the fjord. Waste rock dumps left on the slopes of the Black Angel Mountain are also a main pollution source of lead and zinc not only for the aquatic environment but also for dust dispersal to the terrestrial environment.
Full report in PDF-format (4.4 MB).
