The effects of nickel smelters on water quality and littoral fish species composition in small watercourses in the border area of Finland, Norway and Russia

The Pechenganickel smelters in Nikel and Zapoljarnyi, northwestern Kola Peninsula, have been among the world's largest point sources of SO 2 , Ni and Cu emissions. In order to examine the effects of airborne emissions, the water quality of 35 small lakes and brooks in Finland, Norway and Russia, 1-50 km from the smelters, was surveyed, and fish of stony shores of these lakes and brooks were sampled by electrofishing in 2004 or 2005. The results demonstrated that in the study area the airborne emissions of the smelters have not caused any widespread damage to fish populations even in the most sensitive small waters. The small waters close to the smelters (roughly within a 10 km radius) are well buffered against the effects of high sulphate deposition. Extremely high concentrations of the heavy metals Ni and Cu, however, are a local threat to biota in small waters there, and a few lakes that have apparently lost their fish populations were found. In the border area of Russia, Norway and Finland, acidification is currently only a problem in some very small and sensitive waters located in the local highland areas, 15-50 km from the smelters. There, lakes with a low buffering capacity (alkalinity < 0.05 mmol 1 -1 ) can be found and some fish populations, mainly minnows, have probably been lost. The SO 2 emissions from the smelters have declined to approximately one third of the maximum level in the late 1970s, and this can be seen in a general recovery of the buffering capacity of small lakes such as those in the Finnish border region, 40-50 km west of the smelters.