G. N. Koptsik

Heavy metals in soils near the nickel smelter: chemistry, spatial variation, and impacts on plant diversity

Air pollution induced changes were observed both in plant communities and in soil chemistry in forest ecosystems near the nickel-copper smelter in the Kola Peninsula, Russia. All measured forest plant community parameters describing their floristic composition and structure were affected by pollution. Heavy metals were significantly concentrated in organic horizons of forest soils. The concentrations of ammonium acetate-extractable nickel and copper in organic horizons near the smelter were approximately two orders of magnitude higher than the background levels in the region. Based on pH values, air pollution has not resulted in a detectable topsoil acidification near the smelter. However, concentrations of extractable magnesium, potassium and nitrogen in organic horizons tended to be lower towards the smelter. The spatial variability of data obtained results in necessity of the two complementary, macroscopic and microscopic, approaches to ecosystem investigation. The macroscopic approach better revealed the influence of pollution. The ordination of the major species diversity indexes was highly related to soil properties, suggesting that the content of heavy metals and nutrients is the best soil related predictor of species diversity in polluted areas. Besides direct input of pollutants from the atmosphere, soil contamination and nutritional disturbance contribute significantly to the observed vegetation damage in subarctic forest ecosystems.

Modern approaches to remediation of heavy metal polluted soils: A review

The main principles and approaches to remediation of in situ polluted soils aimed at the removal or control of heavy metals (washing, stabilization, phytoremediation, and natural restoration) are analyzed. The prospects of gentle methods of stabilization oriented at the reduction of the mobility and biological availability of heavy metals due to the processes of adsorption, ionic exchange, and precipitation are emphasized. The use of sorbents and the traditional application of liming and phosphates to fix metal pollutants in soils is considered. The necessary conditions for successful soil remediation are the assessment of its economic efficiency, the analysis of the ecological risks, and confirming the achievement of the planned purposes related to the content of available metals in the soils.

Problems and prospects concerning the phytoremediation of heavy metal polluted soils: A review

The current state, problems, and prospects of phymoremediation of heavy metal polluted soils are analyzed. The main attention is paid to the phytoextraction and phytostabilization as the most widespread and alternative methods of soil phytoremediation. The efficiency of phymoremediation is related to the natural capability of plants for the accumulation and translocation of metals, their tolerance to a high content of metals, the plant biomass, and the amendments applied. The advantages and disadvantages of phytoremediation as compared to other methods of remediation of polluted soils in situ are considered. Examples of successful phytoextraction and phytomining for cleaning up of contaminated soils in Rasteburg (South Africa) and the phytostabilization of technogenic barrens nearby the copper-nickel plants in Sudbury (Ontario, Canada) and in the Kola Subarctic (Russia) are presented.

Calculations of weathering rate and soil solution chemistry for forest soils in the Norwegian-Russian border area with the PROFILE model

Abstract Potential response of forest soils to S deposition in the Norwegian-Russian border area in the surroundings of the Pechenganikel smelters, the major S emitters in northern Europe, has been assessed with the PROFILE model. The release rate of base cations due to weathering range from 0.05 to 0.28 kmol c /ha/yr in the 0–50 cm soil layer, thus demonstrating the high sensitivity of the coarse and thin podzols studied. Calculated steady-state BC/Al values are significantly lower than the presumed critical value of 1, which indicate possible negative effect on vegetation through soil acidification. According to the model calculations future S deposition has to be very low in order to stop the ongoing acidification and prevent vegetation damage. However, model assumptions, uncertainty in input data and critical chemical values applied implies that modelling results must be interpreted carefully.

Effects of acid deposition on acidity and exchangeable cations in podzols of the Kola Peninsula

Response of soil and soil water of podzols in the Kola Peninsula to acid deposition was estimated under both field and laboratory conditions. A significant increasing trend of exchangeable acidity in organic (O) horizons and exchangeable Al in podzolic (E) horizons of podzols with distance from the nickel smelter was observed. The simulated rain at pH 4.5 did not alter chemical properties of soils and soil solutions. As much as 95–99% of the applied H+ ions were retained by soils and appeared in the percolates after a treatment period that depended on acid load and soil thickness. Ca and Mg in soil solutions were highly sensitive to acid loading. Simulated acid rain enhanced the leaching of exchangeable base cations out of root zone. Acid inputs resulted in decreased pH, amount of exchangeable base cations and base saturation, in elevated exchangeable acidity and its Al fraction in soil solid phase. The most significant changes occurred in O and E horizons. Substantial amounts of both Ca and Mg can be lost from the root zone of podzols in the north-western Kola, subjected to acid deposition, thus leading to forest productivity damage.

Ordination of Plant Communities in Forest Biogeocenoses under Conditions of Air Pollution in the Northern Kola Peninsula

The species diversity and structure of the tree, herb–dwarf shrub, and moss–lichen layers in the biogeocenoses (BGCs) of pine forests of the Kola Peninsula were analyzed in the zone affected by the Pechenganikel Combined Works. Relationships of the diversity of phytocenoses with the amount of atmospheric fallout and the concentrations of accessible compounds of polluting elements (nickel and copper) and nutrients (potassium, magnesium, and nitrogen) in forest litters were revealed.

Critical loads of acid deposition for forest ecosystems in the Kola Peninsula

We assessed critical loads of acid deposition and their exceedance for soils in the Kola Peninsula using a simple balance method and mapped them within 1.0° × 0.5° longitude/latitude grid cells. Critical loads of acidity vary from 200 to 800 molc/ha/y with the type of soil, parent rock, vegetation and climatic conditions. The critical deposition values are dominated by S contribution. Present sulphur depositions are higher than critical values in the large part of the Kola Peninsula (about 40% of total area). The greatest excess (800–1200 molc/ha/y) occur in north-western and western parts, especially in surroundings of nickel smelter in Nickel. Terrestrial ecosystems in the north-western Kola Peninsula are particularly susceptible to acid deposition damage due to relatively high soil sensitivity and heavy sulphur deposition.

Efficiency of remediation of technogenic barrens around the Pechenganikel works in the Kola Subarctic

Remediation of the technogenic barrens around the Pechenganikel works on the Kola Peninsula resulted in the improvement of the soil properties, namely, in a decrease in acidity and enrichment with nutrients, which continued for several years. However, the reaction of most of the treated soils remained strongly acid, and the concentrations of available calcium, magnesium, potassium, and phosphorus were much lower than their background levels and the demands of the plants for nutrients (especially, for magnesium and potassium). The soils were depleted in available manganese and zinc. Most of the treated soils contained the same (or higher) amounts of available nickel and copper compounds in comparison with their untreated analogues. The willow plantations on the remediated plots were in a satisfactory state, but they experienced a deficit of magnesium, manganese, and zinc; they consumed elevated amounts of nickel and copper. Recommendations on the nutrient regime of the soils aimed at decreasing the mobility and biological availability of heavy metals were made.

Emission of CO2 by soils in the impact zone of the Severonikel smelter in the Kola subarctic region

The intensity of the in situ soil respiration in the background northern taiga spruce forests of the Kola subarctic region reaches 120–290 mg C-CO2/m2 per h. In the impact zone of the Severonikel smelter, it decreases to 90–140, 30, and 15–30 mg C-CO2/m2 per h at the stages of spruce defoliation, spruce-birch woodland, and technogenic barrens of the technogenic succession, respectively. For the first time, the impact of the industrial pollution on root respiration has been assessed, and the dependences of the CO2 emission, the contribution of mineral soil horizons to this process, the microbial biomass, and root respiration on the concentrations of available nickel and copper compounds have been determined. The efficiency of two remediation technologies applied to technogenic barrens near the smelter has been evaluated on the basis of four parameters of the soil biological activity. The results indicate that remediation with the creation of a new filled soil layer is more efficient than chemical and phytoremediation methods.

Uptake of nutrients and heavy metals by pine trees under atmospheric pollution

Pollution-induced changes in concentrations of elements in pine needles, branches, stem bark, and wood were investigated on 12 plots along the pollution gradient at distances of 5 to 77 km from the Pechenganikel copper-nickel smelter on the Kola Peninsula (northwestern Russia), the largest emitter of sulfur and heavy metals in northern Europe. Close to the pollution source, concentrations of S, Ni, Cu, Pb, and Cd in all the pine compartments were higher as compared to their background levels, while the Zn concentrations were lower. The concentrations of Ni and Cd—the main metals emitted—were the highest in all the pine compartments. Age-related variations in the needle composition were comparable to those at the background plots. Branches and, especially, stem bark, were richer in heavy metals than other tissues and, in addition to wood, contributed significantly to the accumulation of metals in the biomass of the polluted pine forests. Changes in the chemical composition of plant tissues could be explained by changes in element concentrations in the soils and by direct element uptake from the air, as well as by the antagonistic relationships between the elements.