History[ edit ] In , iodine was discovered by French chemist Bernard Courtois ,   who was born to a manufacturer of saltpeter an essential component of gunpowder. At the time of the Napoleonic Wars , saltpeter was in great demand in France. Saltpeter produced from French nitre beds required sodium carbonate , which could be isolated from seaweed collected on the coasts of Normandy and Brittany. To isolate the sodium carbonate, seaweed was burned and the ash washed with water. The remaining waste was destroyed by adding sulfuric acid. Courtois once added excessive sulfuric acid and a cloud of purple vapour rose.
The Larsen C Ice Shelf growing rift
What is happening around the Antarctic Peninsula? This is a region of very rapid warming, and this has resulted in a whole suite of glaciological changes. What are the implications of this change for us? How do glaciers respond to climate change, how are they related and linked, and what is driving these changes? This article summarises glaciers and climate change around the Antarctic Peninsula.
Temperatures are rising Figure 2.
The Larsen B Ice Shelf, shown in Figure 5, has been stable throughout the Holocene and this is the first time it has collapsed in the last 10, years.
Antarctic Peninsula ice shelves Ice shelf collapse on the Antarctic Peninsula Rifting on Larsen C Impact of calving the large iceberg Sea level rise following ice-shelf collapse References Comments Antarctic Peninsula ice shelves The Antarctic Peninsula is fringed by floating ice shelves. They are floating extensions of the glaciers on land, and receive mass by snowfall and marine freeze-on. They lose mass by melting at their base and by calving icebergs. Larsen C Ice Shelf, the largest ice shelf on the Antarctic Peninsula, is currently being closely watched.
Following a series of high-profile ice-shelf collapse events on the Antarctic Peninsula over the last few decades, all eyes are watching Larsen C and wondering when, and if, it will collapse. This could destabilise the ice shelf, making it more susceptible to a total collapse. The ice shelf, which is approximately the size of Wales, can be seen in the embedded Google Maps below.
Glacier change in Antarctica
Hoke, Q, Xu, W. Sentinel-1 observations of the Menyuan earthquake: Structure and geometry of the Aksay restraining double bend along the Altyn Tagh Fault, northern Tibet, imaged using magnetotelluric method. Geophysical Research Letters, 44, , doi:
For most human activities involving minerals and raw materials, the levels of exposure to these radionuclides are not significantly greater than normal background levels and are not of concern for radiation protection.
NORM results from activities such as burning coal, making and using fertilisers, oil and gas production. Uranium mining exposes those involved to NORM in the uranium orebody. Radon in homes is one occurrence of NORM which may give rise to concern and action to control it, by ventilation. All minerals and raw materials contain radionuclides of natural origin. The most important for the purposes of radiation protection are the radionuclides in the U and Th decay series. For most human activities involving minerals and raw materials, the levels of exposure to these radionuclides are not significantly greater than normal background levels and are not of concern for radiation protection.
However, certain work activities can give rise to significantly enhanced exposures that may need to be controlled by regulation. Material giving rise to these enhanced exposures has become known as naturally occurring radioactive material NORM. NORM is the acronym for Naturally Occurring Radioactive Material, which potentially includes all radioactive elements found in the environment. However, the term is used more specifically for all naturally occurring radioactive materials where human activities have increased the potential for exposure compared with the unaltered situation.
Long-lived radioactive elements such as uranium, thorium and potassium and any of their decay products, such as radium and radon are examples of NORM. These elements have always been present in the Earth’s crust and atmosphere, and are concentrated in some places, such as uranium orebodies which may be mined. However from the perspective of radiation doses to people, such a distinction is completely arbitrary.
However certain industries handle significant quantities of NORM, which usually ends up in their waste streams, or in the case of uranium mining, the tailings dam.
Courtois once added excessive sulfuric acid and a cloud of purple vapour rose.