HISTORY OF ATMOSPHERIC LEAD DEPOSITION SINCE 12,370 C-14 YR BP FROM APEAT BOG, JURA MOUNTAINS, SWITZERLAND

A continuous record of atmospheric Lead since 12,370 carbon-14 years b efore the present (C-14 yr BP) is preserved in a Swiss peat bog. Enhan ced fluxes caused by climate changes reached their maxima 10,590 C-14: y, BP (Younger Dryas) and 8230 C-14 yr BP. Soil erosion caused by for est clearing and agricultural tillage increased Lead deposition after 5320 C-14 yr BP. Increasing lead/scandium and decreasing Lead-206/lead -207 beginning 3000 C-14 yr BP indicate the beginning of Lead pollutio n from mining and smelting, and anthropogenic sources have dominated L ead emissions ever since. The greatest Lead flux(15.7 milligrams per s quare meter per year in A.D. 1979) was 1570 times the natural, backgro und value (0.01 milligram per square meter per year from 8030 to 5320 C-14 yr BP).