Hot springs in Greenland have no breaking news value. There are thousands of them, and they have been known ever since the first Scandinavians emigrated to Greenland about a thousand years ago. On the Island of Disko alone there are over 2000 hot springs. The most famous and one of the warmest of them all are however situated on the Uunartoq Island near the village of Alluitsup Paa (in my youth known as Sydprøven in Danish). Over the last 150 years it has been regularly studied by biologists, and over this period measurements at the bottom have constantly shown temperatures ranging from 40°C to 41.9°C, and there is no reason to believe that this temperature range has changed over the last thousand years. Compared with the around 800 hot springs in Iceland with an average water temperature of around 75°C this is not extremely hot - but more like warm, I would say. The difference lies in the volcanic activity in Iceland -- the Greenlandish hot springs are not related to any volcanic activity. Geothermal springs without any connections to volcanoes or hot magmas are however not at all unusual. The water issuing from a hot spring is heated by geothermal heat. In general, the temperature of rocks within the earth increases with depth. If water percolates deeply enough, it will be heated as it comes into contact with hotter rocks, The now warmer water will seek its way upwards through cracks and faults and, if still hot enough, emanate as a hot spring. The water from hot springs in non-volcanic areas is heated in this manner and such springs are known all over the world. Some authors make a distinction between hot springs with water above 37°C and warm springs with water below 37°C (normal human body temperature). There is however no universally accepted definition of a hot spring, so that a hot spring may just mean any spring with water temperatures above its surroundings. Probably the most general definition of a hot spring is that it has the same temperature all year round and is warmer than the location's average temperature.
There are ruins of a nunnery built near the hot springs on the Uunartoq Island after Greenland was Christianized, around 1000, the choice of construction site may have been related to the hot springs. The surface water is usually between 34 and 38 °C and thus well suited for bathing. That the water should contain radium and for that reason have healing properties is a myth however. Radium has never been found in the water, so if it makes you feel well it is rather because of its temperature. Gas bubbles of pure nitrogen are however rising from the bottom. The nitrogen feeds a.o. nitrogen fixating cyanobacteria, that form thick gelatinous microbial mats.
Before the second world war there were plans to utilize the hot water for various purposes, and they even started digging with the intention of building a public swimming bath, but the war made an end to that.
By the way the Greenlandic word uunartoq means something like “is warming”.