Heavy metal contents in whitefish (Coregonus lavaretus) along a pollution gradient in a subarctic watercourse

Abstract

Metallurgic industry is a source of serious environmental pollution related to the emission of heavy metals. Freshwater systems are focal points for pollution, acting as sinks for contaminants that may end up in fish and humans. The Pasvik watercourse in the border area between Finland, Norway and Russia is located in the vicinity of the Pechenganickel metallurgic enterprises, and the lower part of the watershed drains the Nikel smelters directly through Lake Kuetsjarvi. Heavy metal (Ni, Cu, Cd, Zn, Pb and Hg) concentrations in environment (water and sediments) and whitefish Coregonus lavaretus tissue (gills, liver, kidney and muscle) were contrasted between five lake localities situated along a spatial gradient of increasing distance (5-100 km) to the smelters. The heavy metal concentrations, in particular Ni, Cu and Cd, were highly elevated in Kuetsjarvi, but steeply declined with increasing distance to the smelters and were moderate or low in the other four localities. The study demonstrates that the majority of metal emissions and runoffs are deposited near the pollution source, and only moderate amounts of the heavy metal contaminants seem to be transported at further distances. Bioaccumulation of Hg occurred in all investigated tissues, and higher Hg concentrations in planktivorous versus benthivorous whitefish furthermore indicated that pelagic foraging is associated with higher levels of Hg biomagnification. Potential population ecology impacts of high heavy metal contaminations where mainly observed in whitefish in Kuetsjarvi, which showed depletions in growth rate, condition factor and size and age at maturation.

The Impact of a Nickel-Copper Smelter on Concentrations of Toxic Elements in Local Wild Food from the Norwegian, Finnish, and Russian Border Regions

“…The elevated Ni, Co, and Cd concentrations in whitefish and the elevated Co concentrations in pike that we observed in Kuetsjarvi Lake are in agreement with previous studies on Ni and Cd in different tissues of whitefish and perch [6,10,13], and suggest that the smelter is a source of these toxic elements. Indeed, Kuetsjarvi Lake receives wastewater from both the Ni-Cu smelter and the city of Nikel, and, due to their close vicinity, it is difficult to distinguish the proportion of toxic elements they emit individually.…”

“…Indeed, Kuetsjarvi Lake receives wastewater from both the Ni-Cu smelter and the city of Nikel, and, due to their close vicinity, it is difficult to distinguish the proportion of toxic elements they emit individually. We observed no spatial trend for Hg concentrations in fish, which is in agreement with previous studies from this area [10,13]. Still, concentrations in sediments have indicated Hg emission from the Ni-Cu smelter in addition to other local anthropogenic activities and long-range transport [3,5].…”

“…Although trace amounts of Cu are essential to humans, larger amounts can be hazardous [12]. Other toxic elements, such as arsenic (As), lead (Pb), cadmium (Cd), and mercury (Hg) are also emitted by the complex, but studies disagree on the magnitude of these emissions [1,3,4,5,6,7,10,13,14]. It is also likely that As, Pb, Cd, and Hg emissions are camouflaged by deposition from long-range transport and other local anthropogenic or geogenic sources [3,4,5].…”

“…Although not in the direction of the prevailing winds, a previous study has suggested that Ni and Cu emissions from the Pechenganickel complex may even travel as far as Greenland [16]. In addition to airborne pollution, wastewater discharge from the Ni-Cu smelter, as well as from the city of Nikel, conveys toxic elements into Kuetsjarvi Lake, located in the Pasvik watercourse (forming the border between Norway and Russia) close to the smelter [13,17,18,19]. …”

“…Elevated environmental concentrations of toxic elements such as Ni, Cu, and several others in these border regions, as well as several air pollution events [1,2,3,4,5,6,9,10,13,14,18,22,23,24,25,26,27], have given rise to concern among these residents [27], some of whom frequently use foods that grow wild in these regions. Therefore, knowledge of the concentrations of toxic elements in local wild foods is important, both to protect nature and to protect humans that consume local wild food.…”