Snow and ice strata

Of great interest and value have been analyses of snow-formed ice in the polar regions. In these ice sheets, we find preserved records of aerosols from the marine atmosphere. Recent work on lead in Greenland and Antarctic snow strata (38) and on sulfate and mercury also in Greenland ice and snow (56-58), clearly show increases in these constituents in recent decades which might be attributable to man-made pollution. 

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