S. V. 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.

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.

On the calculation of the surface area of different soil size fractions

Abstract A model that accounts for contributions to the total surface area (SA) by different size fractions of the soil is considered from a theoretical point of view. Calculations, based on continuous particle sizes and forms, explain SA mainly as a geometric SA. It is common for coarse soils to have a discrepancy between the measured SA, say inferred from adsorption of gases, and the calculated geometric area of up to two orders of magnitude. This discrepancy is removed by the present method. Size distribution is the main factor influencing the SA; taking particle forms into account resulted in a 2–3 times increase of SA. The several orders of magnitude range of grain sizes leads to crucial variations in the contributions that soil fractions make to weight, SA and number of grains. The fundamental lower limit of variation of soil properties, originating from the discrete nature of soils, is introduced. Despite the deterministic physical origin of SA, high sensitivity to the finest fractions can be considered on the environmental scale as a cause of the dual—stochastic and deterministic—nature of SA. Small variations of weight within experimental error and the fundamental limit may result in significant variations of SA, close to the same order of magnitude for coarse soils. An empirical equation ( Sverdrup, 1990 ) relates textural data to SA at landscape scale. It is applicable to a collection of samples, while individual samples must be characterised on a probabilistic basis.

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.

Efficiency of Remediation of Technogenic Barrens around the Severonikel Factory on the Kola Peninsula

The soil of the technogenic barrens formed under the impact of long-term air pollution around the Severonikel factory is acidic, depleted in nutrients, contaminated with heavy metals, and strongly eroded. Remediation by coating the topsoil with a fertile layer developed based on organic and mineral compounds is accompanied by decreasing the soil acidity and enrichment with carbon and nutrients (nitrogen, phosphorus, potassium, calcium, magnesium, manganese, and zinc). However, under the existing operational conditions, the surface layers of most treated soils accumulate nickel and, especially, copper. The efficiency of remediation depends on the composition and thickness of the constructed layer, as well as the related measures, which should be supplemented by repeated liming.

Analysis of the Relationship between Soil and Vegetation in Forest Biogeocenoses by the Principal Component Method

Coordinated soil–geobotanical studies revealed a close correlation between the species diversity of phytocenoses and soil properties in the Russkii Sever National Nature Park (Vologda oblast). Soil acidity, together with the concentrations of exchangeable calcium, potassium, and magnesium, is a factor determining variations of species diversity indices for vascular plants and bryophytes in forest biogeocenoses.

Pine Needle Chemistry Near a Large Point SO2 Source in Northern Fennoscandia

Air pollution induced changes in pine needle chemistry were observed at sample sites in the surroundings of the Pechenganikel smelter. Close to the smelter, elevated concentrations of Ni, Cu and S were found (Ni: 0.7–1 mmol/kg, Cu: 0.4–0.5, and S 40–60 mmol/kg). Close to the pollution source, needles were enriched in Ni and Cu by needle age. Correlation and principal component analyses show that changes in the element composition of pine needles depended on air pollution and on natural factors as well. The contribution from air pollution increased with needle age. Besides direct input of pollutants from atmosphere, soil contamination and nutritional disturbance contributed significantly to the observed changes.

Input and migration of dissolved organic carbon in soils of forest ecosystems in the subzone of deciduous–coniferous forests

The results of four-year monitoring of natural waters in forest ecosystems of the Zvenigorod Biological Station (Moscow State University, Moscow oblast) show regular changes in the concentrations and fluxes of dissolved organic carbon (DOC) within the atmospheric precipitation–throughfall–soil waters system. Precipitation passing through the tree canopy is enriched with DOC (2–3 and 9–24 mg/L). The average carbon concentration in soil waters reaches 100–110 mg/L in complex spruce and pine–spruce forests and does not exceed 40–60 mg/L in spruce–birch forests.The DOC concentration in natural waters is subject to high spatial and temporal variability expressed both in seasonal and long-term cycles. The lack of coordination between temporal peaks confirms that air-borne or canopy-derived DOC has little impact on DOC in soil waters. DOC leaching from the upper 40-cm soil layer during the growing period is higher than throughfall input. The highest DOC losses are observed in weakly derno–shallow podzolic soil in the complex spruce forest, which has the most coarse-grained texture.

Assessment of the risk of excess sulfur input into terrestrial ecosystems of the Kola Peninsula

The tolerance of terrestrial ecosystems of the Kola Peninsula to atmospheric deposition of acid-forming sulfur compounds and the risk of their excess input into these ecosystems have been assessed on the basis of the critical load concept. The most sensitive ecosystems (critical sulfur load <400 equiv/ha per year) occupy 58% of the total area of the peninsula. These are mainly pine, spruce, and birch forests (including open and crooked birch forests) growing on podzols formed on sandy boulder-pebble glacial deposits. The zones of ecological risk cover the northwestern and central parts of the peninsula near the Pechenganikel and Severonikel combined works (20% of the total area).