Sr isotopic signature in plant-derived Ca in rain

The Sr-87/Sr-86 ratios in rain at three sites in Japan were about 0.706 to 0.712, whereas those at one site in central Korea were higher (0.711 to 0.7 16), reflecting the difference in geology between the two countries. Becaus e the Sr-87/Sr-86 ratios of exchangeable sites in soil minerals are indisti nguishable from those of associated plants, aerosol Sr originating from bot h can be grouped together as plant-derived Sr. Spatial and temporal variati ons in Sr-87/Sr-86 and Sr/Ca ratios in the rain suggest the presence of pla nt-derived Sr and Ca in addition to Sr and Ca derived from sea-salt, acid-s oluble aeolian carbonate from China, and cement-derived carbonate. However, systematic data on the Sr-87/Sr-86 ratios and elemental concentrations of soils, plants, fly-ash, and road dust are required to put reliable constrai nts on the provenance of atmospheric Ca.