Sampling of glacier ice

Summary

As part of the "Ice and water export project", sampling of glacier ice in front of the glacier Narsap Sermia in the inner part of Nuup Kangerlua (Godthåbs Fjord) has been carried out in July 2008. Before the field survey, three persons were interviewed in Nuuk in order to evaluate the access conditions based on personal experience. The area is covered with sea ice from November to May and access is only possible with ice classed vessels. After the sea ice breaks up, the area is filled with ice bergs and growlers, but the situation varies during the summer due to wind and current conditions. Often it is possible to navigate along the northern coast to the boundary of the ice filled area. Some years, it is also possible to navigate almost to the front edge of the glacier. The sampling from ice growlers took place in mid July from M/V Masik, equipped with a crane. Three ice growlers about 1 m³ in size were collected from various locations. Each ice growler was lifted by crane on to the deck of the ship and allowed to equilibrate for one hour with the ships machinery and engine turned off. Each ice growler was cut in half, and four samples were taken from the surface to the centre from each half section. A sea water sample from each location was collected at the same time as each ice growler. Samples for chemical analysis were thawed out, poured into sampling containers and placed in cooler boxes. Samples for microbiological analysis at the laboratory of Nuuk hospital were kept frozen in a chest freeze onboard the ship. Samples of the seawater for microbiological analyses were filtered on board, and the filters were placed on MacConkey agar plates for later analysis. All samples were analysed on board for conductivity and pH. The centre samples were analysed for inorganic components, NVOC (nonvolatile organic carbon), Clostridium perfringens spores and Pseudomonas aeruginosa at MILANA laboratory in Denmark. The ice samples between the surface and the centre and the sea water samples we analysed for conductivity, pH, and chloride at MILANA in Denmark and for colony counts, total coliforms, E. coli, faecal streptococcus and Clostridium perfringens at the Nuuk hospital laboratory. Both the field and laboratory results demonstrate that no penetration of sea water into the ice growlers occurs. The results of the chemical analysis are compared with the Greenlandic, Danish and EU quality criteria for drinking water. The analyses demonstrate that the water quality is characterised by a very low content of inorganic components and has no buffer capacity. The water quality is generally acceptable as Sampling of glacier ice – field investigations 2008 3 drinking water, but conductivity and hydrogen carbonate are too low compared with Greenlandic quality requirements for drinking water from the tab, but not with respect to quality requirements for bottled water. The iron content is too high in some samples, and it is undesirable since this can cause precipitation and discolouration. Iron is however not considered a health problem, and WHO has no guideline value for iron. The microbiological quality of the ice samples was generally very good and well below criteria for colony counts. One sample, however, showed an aberrant result of 1 germ for Clostridium perfringens, but the result is assessed as unlikely as no other bacterial contamination was determined in the sample or in the other samples. An earlier investigation of ice samples from the side of Narsap glacier in 2006 had shown no content of heavy metals, polycyclic aromatic hydrocarbons (PAH), pesticides, and polycyclic biphenyls (PCB). For this reason, the present study has not included analyses for these components. However, the earlier analytic results of the samples showed a much higher content of total solids and NVOC and higher turbidity, which is presumably attributable to the shallow depth and location of sample collection on the glacier. The present 2008 investigation has demonstrated that water quality in ice growlers fished-up in front of the glacier is suitable for production of bottled water or ice products. For commercial use, a fishing trawler with equipment and facilities for the hygienic storage and treatment of foodstuff will be required. By collecting the ice growlers from a confined area with no mixing of ice from other glacier sources, a more uniform product can be produced. This method is considered to be the most sustainable, as it has no effect on the glacier itself or the land along the glacier.