A researcher using an atomic absorption spectrometer at the British Antarctic Survey (BAS) headquarters in Cambridge, England. Atomic absorption spectrometry makes it possible to measure extremely small concentrations of about 40 different metals in a sample. At BAS, for instance, the instrument is used to measure the concentrations of metals like lead in samples of snow & ice from Antarctica. It is possible to identify one part of lead in a million million parts, making the instrument a highly sensitive method of investigating heavy metal & other forms of pollution. Photographed 1987.