EFFECT OF ACID DEPOSITION ON SOIL ACIDIFICATION AND METAL MOBILIZATION

Simulated acid rain treatments of pH 5.6, 4.0 and 2.5 in the laborator y produced marked acidification and Al and Zn mobilisation in columns of an homogenised incipient podsolic soil. Exposure of monoliths of th e same soil and an acid brown earth to ambient levels of acid depositi on in the U.K. for 3 a, resulted in soil acidification at higher rainf all and slightly contaminated sites, whilst the drier but more contami nated sites exhibited a more variable response. Changes in DTPA-extrac table Zn did not conform to any obvious pattern, although at 5 of the 6 sites the acid brown earth monoliths underwent a decrease in Zn conc entration. (C) 1996 Elsevier Science Ltd