Interactions between precipitation and Scots pine canopies along a heavy-metal pollution gradient

Bulk precipitation and stand throughfall were collected during 1992-96 at d istances of 0.5, 4 and 8 km from the Harjavalta Cu-Ni smelter, southwestern Finland. The amounts of heavy metals (Cu, Ni, Zn, Fe) and mineral nutrient s in bulk precipitation and throughfall were highest at 0.5 km. Although th e canopy coverage was low at 0.5 km, the amounts of heavy metals intercepte d by the canopy were extremely high. The proportion of foliar leaching rela tive to the wash-off of dry deposition from the needle surfaces decreased o n moving towards the smelter for all elements, except for K. The high rate of K leaching from the needle tissues close to the smelter demonstrated tha t the K throughfall flux has been greatly altered by the heavy pollution lo ad. (C) 1999 Elsevier Science Ltd. All rights reserved.