Analysis of air and snow samples in Antarctica for isotope analysis

Snow samples were collected over a number of seasons for analysis of fission products (deuterium and oxygen isotopes), tritium and sulphur isotope contents. The information would provide the basic data on nuclear products occurring both naturally and as the result of nuclear explosions. Concise methods are used in sampling so that the right density of snow is collected. For fission product samples, 21 lbs of snow at the right density will yield a full 2 gallon sample. Samples are melted in containers and a carrier chemical is added. The quantity of snow meltwater required for tritium samples is one gallon which is roughly 10lbs of snow. The quantity of snow meltwater required for sulphur isotope analysis is five gallons which is approximately 52 lbs. Samples for different analysis results in different collecting containers but in all cases, snow is left in a warm room and allowed to melt before put into storage containers for movement back to a laboratory for testing. Air samples were analysed for CO2. The project involves the exposure of a tray of potassium hydroxide to the air for a period of approximately 7 days. During this time the potassium hydroxide absorbs a certain amount of carbon dioxide from the atmosphere and it is essential that the tray be kept free from local CO2 contamination during this period. The purpose of the final sample is to study the isotopic ratios of the carbon (obtained from the carbon dioxide absorbed by the potassium hydroxide) rather than the total amount of CO2 absorbed during the exposure of the trays contents. Snow sampling began in the 1961-62 field season and samples were mainly collected near Scott Base (snow pit (NZGS 16) and NZGS 13) and from inland Antarctic stations; South Pole and Byrd Station. Opportunistic samples were collected from the western slopes of Mt Erebus at an altitude of approximately 5,500 ft, the Balleny Islands, from several New Zealand and USAP field project sites, the Beardmore Glacier and the HMNZS Endeavour collected samples every 3 degrees of latitude. Potassium hydroxide trays were set out for CO2 sampling at Arrival Heights in most years.