A Paleolimnological Perspective on Arctic Mountain Lake Pollution

Abstract

The chemical composition of sediments from the Arctic mountain Lake Bolshoy Vudjavr, situated in the western part of the Russian Arctic zone, was studied. The lake has been under intense anthropogenic load for more than 90 years since the development of the richest apatite–nepheline deposits in the world started. A 27 cm thick sediment core was sampled in the central part of the lake at the maximum depth of 37.4 m. The concentrations of more than 50 elements were analyzed by the mass spectral method, ICP-MS. The lake sedimentation rate established from the change in the content of the radioactive isotope 210Pb was 2.3 mm/yr. The effluent from apatite–nepheline production and atmospheric fallout enrich the sediments of Lake Bolshoy Vudjavr with alkali and alkaline earth metals, N, P, Mn, Fe, Al compounds, rare earth elements, and trace elements (Sb, Cu, Zn, Pb, Bi, Nb, Ta, Th). Analysis of the forms of elements in the lake sediments showed that the studied elements are mainly found in stable fractions—mineral, acid-soluble, and associated with organic matter. The pollution of the sediments of Lake Bolshoy Vudjavr was assessed by the integral index PLI (Pollution Load Index) and CF (contamination factor). The PLI value sharply increased after the “Apatite” Plant had been launched and a large amount of wastewater from the mines had been released into the lake. The highest PLI values were detected in the sediment layers accumulated during the period 1990s–2000s. Sb (18.2), P (10.3), Sr (7.8), and La (6.0) have the maximum CF values among all the studied elements.

Geochemical Indicators for Paleolimnological Studies of the Anthropogenic Influence on the Environment of the Russian Federation: A Review

“…Sediments most polluted with these metals were found in Lake Kuetsjarvi (the area of the Norway-Russia border) and Lake Nudjavr (the central part of the region). In Murmansk Region, paleolimnological studies of the impact of the mining enterprises determined the increased concentrations of P, Ca, Sr, and rare earth elements in recent sediments, as all these elements are included in produced ore entering water bodies with mine waters and dust [39].…”

“…Studies reported that wastewater and dust emissions from Apatit JSC played a significant role in the pollution of lakes located near this enterprise and its mines. The paleolimnological studies of Lake Bolshoi Vudjavr and Lake Imandra are the most illustrative [37][38][39]. Lake Bolshoi Vudjavr is the largest water body of the Khibiny Massif.…”

“…There were the increases in concentrations of P (up to ~15000 mg/kg, while background level is less ~1000 mg/kg), Ca (up to ~76500 mg/kg, background is ~1500 mg/kg), Sr (up to ~2900 mg/kg, background is ~400 mg/kg), Pb (up to 45.9 mg/kg, background is 9.7 mg/kg), and Cu (up to 225 mg/kg, background is 55 mg/kg) in upper layers of sediments of Lake Bolshoi Vudjavr [37,[39][40][41], which is related to the composition of apatite-nepheline ore and also the influence of the city and the long-range transport of pollutants, including those from the metallurgical combine in Monchegorsk located ~45 km from this lake [42]. Recent studies of sediments of Lake Bolshoi Vudjavr have confirmed previously received data, broadened the range of identified elements, and specified the sedimentation rate in the lake [39,41]. Based on the data on the vertical distribution of the 210 Pb isotope, the sedimentation rate in the water body was 2.3 mm/year.…”

“…Additionally, increased contents of Sb and W in the sediments are related to the operations of the thermal power plant located ~10 km from the lake using coal as fuel [41]. Besides the anthropogenic impact on Lake Bolshoi Vudjavr, paleolimnological studies determined the natural geochemical anomaly of Mo in sediments of the studied lake [39,43]. It was shown that the sediment cores were enriched with Mo both in upper layers (up to 9.9 mg/kg) due to the influence of mine waters and lower layers (up to 15.1 mg/kg) due to the influence of underlying rocks with increased concentrations of this metal.…”

“…The highest concentrations of rare earth elements (up to ~240 mg/kg for La (background is 56.5 mg/kg) and up to ~400 mg/kg for Ce (background is 80.6 mg/kg)) in studied sediments date back to the 1970s, the period of the most active ore production (Figure 10) [38]. Even higher concentrations of rare-earth elements due to the activities of JSC Apatit were found in the upper layers of the sediments of Lake Bolshoi Vudjavr [39]. For instance, the detailed analysis of the sediment core of this lake revealed a tendency towards increased concentrations of La (up to 535 mg/kg, while minimum in the core is 84 mg/kg), Ce (up to 802 mg/kg, while minimum in the core is 128 mg/kg), Sm (up to 44 mg/kg, while minimum in the core is 7.3 mg/kg), and Eu (up to 13 mg/kg, while minimum in the core is 2).…”