THE EFFECT OF EMISSIONS FROM CU-NI SMELTERS AT NIKEL, NW RUSSIA, ON THE QUALITY OF BULK DEPOSITION, STAND THROUGHFALL AND PERCOLATION WATERIN 4 SCOTS PINE STANDS IN NORTHERN NORWAY AND FINLAND

The effects of industrial emissions from Nikel, NW Russia, on the chem ical composition of bulk deposition, stand throughfall and percolation water (depth 5 cm) were studied in four Scots pine stands. The plots were located on dry sites with genetic horizons characteristic of iron -humus podsol. The ground vegetation consisted of Calluna vulgaris and Cladonia spp.. The highest S concentrations in bulk deposition and in stand throughfall were recorded on the sample plot (14 km) closest to Nikel. The S concentration in stand throughfall decreased gradually w ith increasing distance from Nikel. The pH of stand throughfall was so mewhat lower on the plots located at 14, 33 and 58 km from Nikel compa red to that at 132 km. There was no clear gradient in the percolation water pH or S concentrations with respect to the point source. The cop per and nickel concentrations in percolation water were very low, even at the plot (14 km) closest to the point source. The lowest pH values and highest Al, Ca and Mg concentrations in percolation water were re corded on the plot where the DOC concentrations were also the highest. (C) 1998 Elsevier Science Ltd.