THE TRACE-METAL DISSOLUTION KINETICS OF 3 RURAL ATMOSPHERIC AEROSOLS IN A RANGE OF NATURAL FRESH-WATER TYPES

The dissolution kinetics of Pb, Zn and Cu from three rural atmospheric aerosols were studied in a range of natural fresh waters and a synthetic analogue, employing two different experimental systems and analytical techniques (AAS and ASV). The experiments showed that high proportions (27-87% by mass) of the metal contents were rapidly (minutes) released into true solution (i.e. ASV labile), and that after 30 min there was little or no further dissolution, even after 1 week. The extent of Zn (74 +/- 8%) dissolution was invariably greater than that of Pb (41 +/- 15%) and Cu (47 +/- 11%), and dissolution of Pb and Zn increased with decreasing pH. There was no evidence for any increased dissolution associated with dissolved organics.