Copper-nickel Smelter Research Articles

Diversity but Not Overall Abundance of Moths and Butterflies (Insecta: Lepidoptera) Decreases around Two Arctic Polluters.

Alarming reports on the rapid decline of insects during the past decades call for the exploration of potential drivers of this process. Here, we test the hypothesis that the overall abundance and diversity of moths and butterflies (Lepidoptera) decrease under the impact of industrial pollution in the fragile arctic environment. For this purpose, experienced collectors netted adult Lepidoptera at five tundra sites located 0.5 to 45.3 km from the ore-roasting plant in Zapolyarnyy and at five forest sites located 1.4 to 37.8 km from the copper-nickel smelter at Nikel, in the Murmansk region of Russia. The analysis of the 100 samples collected from 2003 to 2008 and containing 2312 individuals of 122 species revealed that the diversity of Lepidoptera declined significantly near both of these polluters due to both decreases in species richness and changes in the abundance of individual species, whereas the overall abundance of moths and butterflies was independent of the pollution load. These patterns did not differ between Nikel and Zapolyarnyy, and they were consistent with patterns previously found near the copper-nickel smelter at Monchegorsk. The abundances of Lepidoptera species showed variable changes along pollution gradients, from significantly negative to significantly positive, but individual species showed similar density changes around these three polluters. Disproportional increases in the abundance of a few pollution-tolerant species change the community structure and explain why the overall abundance of moths and butterflies does not decline even in localities experiencing extreme loads of sulphur dioxide and heavy metals.

Pollution-Induced Changes in the Composition of Atmospheric Deposition and Soil Waters in Coniferous Forests at the Northern Tree Line

This study examines the dynamics of the composition of atmospheric precipitation and soil water in coniferous forests under the influence of atmospheric emissions from the Severonickel Copper–Nickel Smelter in Russia’s Murmansk region. We studied dwarf shrub-green moss spruce forests and lichen-shrub pine forests, the most common in the boreal zone. Our results showed a significant intra- (below and between the crowns) and inter-biogeocenotic (spruce and pine forests) variation in the composition of atmospheric precipitation and soil water in forests exposed to air pollution. The concentrations of main pollutants in atmospheric fallout and soil water are tens (sulfates) and hundreds (heavy metals) times higher than in the background areas and typically higher below the crowns. The long-term dynamics (between 1999 and 2020) of the composition of atmospheric fallout and soil water in coniferous forests in the background areas and defoliating forests demonstrates a significant increase in nickel concentrations in recent years. This may be due to an increase in nickel concentrations in aerosols propagating over considerable distances. In pollution-induced sparse forests, a trend was found toward a decrease in the concentration of pollutants, which may indicate a decrease in the fallout of pollutants in the composition of larger particles close to the smelter.

Recovery of moth and butterfly (Lepidoptera) communities in a polluted region following emission decline.

Environmental pollution is one of the major drivers of the present-day decline in global biodiversity. However, the links between the effects of industrial pollution on insect communities and the underlying species-specific responses remain poorly understood. We explored the spatial pattern in insect communities by analysing 581 samples of moths and butterflies (containing 25,628 individuals of 345 species) collected along a strong pollution gradient in subarctic Russia, and we recorded temporal changes in these communities during the pollution decline that occurred from 1992 to 2006. In the 1990s, the diversity of the Lepidoptera community was positively correlated with the distance from the copper-nickel smelter at Monchegorsk. The overall abundance of Lepidoptera did not change along the pollution gradient, although the abundance of many species decreased with increasing pollution. The responses of each individual species to pollution were associated with its life history traits. The abundances of monophagous species that fed inside live plant tissues and hibernated as imagoes or pupae were not affected by pollution, whereas the abundances of oligophagous and polyphagous species that fed externally on plants and hibernated as larvae generally declined near the smelter. Substantial decreases in aerial emissions from the smelter between 1992 and 2006 resulted in an increase in the diversity of moths and butterflies in severely polluted habitats, whereas their overall abundance did not change. This recovery of the Lepidoptera community occurred due to the reappearance of rare species that had been previously extirpated by pollution and was observed despite the lack of any signs of recovery of the vegetation in the heavily polluted sites. We conclude that the recovery trajectories of insect communities following emission control can be predicted from studies of their changes along spatial pollution gradients by using space-for-time substitution.

Choose your amendment wisely: Zero-valent iron nanoparticles offered no advantage over microparticles in a laboratory study on metal immobilization in a contaminated soil

The potential use of zero-valent iron (ZVI) nanoparticles (i.e., <100 nm in size) for the remediation of metal-contaminated soils has sparked a flurry of research in recent years. However, even reading a large number of these papers cannot completely dispel doubts that ZVI nanoparticles are indeed superior to ZVI microparticles (e.g., iron powder or grit) in immobilizing metals and metalloids in soils. Our primary objective was to compare the adsorption properties of iron-based amendments (ZVI micro- and nanoparticles, natural iron oxides) supplied in a biochar matrix in soils contaminated by a copper-nickel (Cu/Ni) smelter on the Kola Peninsula in Russia. The following iron-containing amendments were added to the studied soil: a composite of ZVI nanoparticles and biochar (synthesized by pyrolysis of iron-impregnated biochar), a mixture of iron powder (i.e., ZVI microparticles) with biochar, and a mixture of iron oxides (from natural ferromanganese nodules) with biochar. Perennial ryegrass (Lolium perenne L.) was grown in pots on untreated and amended soils for 21 days under laboratory conditions. In our time-limited study, ZVI nanoparticles did not prove superior to ZVI microparticles or natural iron oxides at immobilizing metals in copper- and nickel-contaminated soil. In other words, ZVI particles size was irrelevant under the experimental setup of this study in its effects on exchangeable metal concentrations, foliar elemental concentrations, and plant growth.

Foliar stable isotope ratios of carbon and nitrogen in boreal forest plants exposed to long-term pollution from the nickel-copper smelter at Monchegorsk, Russia

Long-term exposure to primary air pollutants, such as sulphur dioxide (SO2) and nitrogen oxides (NOx), alters the structure and functions of forest ecosystems. Many biochemical and biogeochemical processes discriminate against the heavier isotopes in a mixture; thus, the values of δ13C and δ15N (i.e. the ratio of stable isotopes 13C to 12C and that of 15 N to 14 N, respectively) may give insights into changes in ecosystem processes and identify the immediate drivers of these changes. We studied sources of variation in the δ13C and δ15N values in the foliage of eight boreal forest C3 plants at 10 sites located at the distance of 1–40 km from the Monchegorsk nickel-copper smelter in Russia. From 1939‒2019, this smelter emitted over 14,000,000 metric tons (t) of SO2, 250,000 t of metals, primarily nickel and copper, and 140,000 t of NOx. The δ13C value in evergreen plants and the δ15N value in all plants increased near the smelter independently of the plant mycorrhizal type. We attribute the pollution-related increase in the foliar δ13C values of evergreen species mainly to direct effects of SO2 on stomatal conductance, in combination with pollution-related water stress, which jointly override the potential opposite effect of increasing ambient CO2 concentration on δ13C values. Stomatal uptake of NOx and root uptake of 15N-enriched organic N compounds and NH4+ may explain the increased foliar δ15N values and elevated foliar N concentrations, especially in the evergreen trees (Pinus sylvestris), close to Monchegorsk, where the soil inorganic N supply is reduced due to the impact of long-term SO2 and heavy metal emissions on plant biomass. We conclude that, despite the uncertainties in interpreting δ13C and δ15N responses to pollution, the Monchegorsk smelter has imposed and still imposes a great impact on C and N cycling in the surrounding N-limited subarctic forest ecosystems.

The Fluctuating Asymmetry of the Butterfly Wing Pattern Does Not Change along an Industrial Pollution Gradient

The rapid and selective responses to changes in habitat structure and climate have made butterflies valuable environmental indicators. In this study, we asked whether the decline in butterfly populations near the copper-nickel smelter in Monchegorsk in northwestern Russia is accompanied by phenotypic stress responses to toxic pollutants, expressed as a decrease in body size and an increase in fluctuating asymmetry. We measured the concentrations of nickel and copper, forewing length, and fluctuating asymmetry in two elements of wing patterns in Boloria euphrosyne, Plebejus idas, and Agriades optilete collected 1–65 km from Monchegorsk. Body metal concentrations increased toward the smelter, confirming the local origin of the collected butterflies. The wings of butterflies from the most polluted sites were 5–8% shorter than those in unpolluted localities, suggesting adverse effects of pollution on butterfly fitness due to larval feeding on contaminated plants. However, fluctuating asymmetry averaged across two hindwing spots did not change systematically with pollution, thereby questioning the use of fluctuating asymmetry as an indicator of habitat quality in butterfly conservation projects.

Quantitative Methods to Support Data Acquisition Modernization within Copper Smelters

Sensors and process control systems are essential for process automation and optimization. Many sectors have adapted to the Industry 4.0 paradigm, but copper smelters remain hesitant to implement these technologies without appropriate justification, as many critical functions remain subject to ground operator experience. Recent experiments and industrial trials using radiometric optoelectronic data acquisition, coupled with advanced quantitative methods and expert systems, have successfully distinguished between mineral species in reactive vessels with high classification rates. These experiments demonstrate the increasing potential for the online monitoring of the state of a charge in pyrometallurgical furnaces, allowing data-driven adjustments to critical operational parameters. However, the justification to implement an innovative control system requires a quantitative framework that is conducive to multiphase engineering projects. This paper presents a unified quantitative framework for copper and nickel-copper smelters, which integrates thermochemical modeling into discrete event simulation and is, indeed, able to simulate smelters, with and without a proposed set of sensors, thus quantifying the benefit of these sensors. Sample computations are presented, which are based on the authors’ experiences in smelter reengineering projects.

Decline of Eulia ministrana (Lepidoptera: Tortricidae) in polluted habitats is not accompanied by phenotypic stress responses.

Environmental pollution is currently identified as one of the major drivers of rapid decline of insect populations, and this finding has revitalized interest in insect responses to pollution. We tested the hypothesis that the pollution-induced decline of insect populations can be predicted from phenotypic stress responses expressed as morphological differences between populations inhabiting polluted and unpolluted sites. We explored populations of the brassy tortrix Eulia ministrana in subarctic forests along an environmental disturbance gradient created by long-lasting severe impacts of aerial emissions of the copper-nickel smelter in Monchegorsk, northwestern Russia. We used pheromone traps to measure the population densities of this leafrolling moth and to collect specimens for assessment of three morphological stress indices: size, forewing melanization, and fluctuating asymmetry in wing venation. Wing length of E. ministrana increased by 10%, and neither forewing melanization nor fluctuating asymmetry changed from the unpolluted forest to the heavily polluted industrial barren. However, the population density of E. ministrana decreased 5 to 10 fold in the same pollution gradient. Thus, none of the studied potential morphological stress indicators signaled vulnerability of E. ministrana to environmental pollution and/or to pollution-induced environmental disturbance. We conclude that insect populations can decline without any visible signs of stress. The use of morphological proxies of insect fitness to predict the consequences of human impact on insect populations is therefore risky until causal relationships between these proxies and insect abundance are deciphered.

Assessment of the Composition of Rain Deposition in Coniferous Forests at the Northern Tree Line Subject to Air Pollution

This study is devoted to assessing the interbiogeocenotic and intrabiogeocenotic variation and long-term dynamics of the composition of rain deposition in coniferous forests that are exposed to contamination from the Severonikel Copper-Nickel Smelter Complex (Murmansk oblast), the largest source of pollutant emissions into the atmosphere in Northern Europe. Spruce forests with dwarf shrubs and green mosses and pine forests with dwarf shrubs and lichens, which are common in the boreal zone, are studied at different stages of pollution-induced degradation. The chemical composition of rainwaters is characterized by a significant intra- and intrabiogeocenotic variation. Long-term data confirm that the content of elements is significantly higher below the crowns than between them, with the concentrations and deposition of elements being significantly higher in spruce forests than in pine ones. This difference is determined by different sorption capacities of tree crowns and different levels of leaching of elements from them. The fallout of the main pollutants with rainwaters exceeded the critical levels even in the background areas and was significantly higher in defoliating forests and pollution-induced sparse forests. It is shown that the excess of the critical levels is much more pronounced in rainwaters than in snow ones. The determination of the intra- and interbiogeocenotic differences in the composition of atmospheric fallout allows an earlier and more accurate diagnosis for the excess of critical loads at all degradation stages. The long-term dynamics of the fallout of chemical elements with rainwaters in pine and spruce forests is characterized by a high variability both below and between tree crowns. An increase in nickel concentrations in the background areas from 2013 to 2017 is revealed, which is explained by the growth in the content of pollutants in aerosols spreading over considerable distances.

Water Chemistry of Arctic Lakes under Airborne Contamination of Watersheds

The data on the metal contents and acidification of small lakes caused by airborne contamination of the watershed in three industrial regions of the Arctic—European Russia (Kola region), Western (Yamal-Nenets region) and Eastern Siberia (Norilsk region)—have been presented for the first time. It has been proven that acidification and enrichment by metals of water connect with sulfur dioxide and metals emissions from copper–nickel smelters, contaminating the catchments, with associated gas burning during raw hydrocarbon production. To assess the effects of acid deposition, critical loads and their exceeds were calculated: exceeded by 56% and 12.5%, respectively, in lakes in the Kola region and in the north of Western Siberia; the catchments of the East Siberian region are resistant to acidification. Water enrichment factors (EF) by elements were calculated to show that the waters of the Norilsk and Kola regions are enriched with Ni, Cd, As, Sb and Se as a result of emissions from copper–nickel smelters. The oil and gas industry in the northern regions of Western Siberia lead to the increase in V, Pb and Mo concentrations in the waters. The high values of EF and excess of acidity critical loads for water are explained by the local and transboundary pollution impacts on the catchment of small lakes.

Geochemical Features of Elements Distributions in the Lake Waters of the Arctic Region

Abstract—Data on the water quality and the contents of a large group of elements in small lakes are reported for three regions of the Arctic basin: European Russia (Kola region), Western (Yamal–Nenets district) and Eastern (Norilsk region) Siberia. All studied waters are low-salinity and oligotrophic. The air pollution in the lake waters caused the elevated concentrations of many elements. The waters of the Norilsk and Kola regions are enriched in Ni, Cd, As, Sb and Se owing to the distribution of smoke emissions from copper–nickel smelters over long distances. The petroleum industry leads to increased concentrations of V, Pb, and Mo in water. The degree of anthropogenic influence on the lake waters of the Arctic regions was estimated using the Enrichment Factors (EF). The high values of EF for most part of analyzed elements are explained not only by anthropogenic dispersion of elements, but also by a change in the conditions of element migration and the geochemical features of ore occurrences. The calculations demonstrated the effect of anthropogenic dispersion on the enrichment of Arctic waters by a large group of elements, including toxic ones.

Aquatic environment and anthropogenic factor effects on distribution of trace elements in surface waters of European Russia and Western Siberia

The distribution of trace elements of anthropogenic origin, especially toxic metals, is an environmental problem. We present the first results of research into the geochemistry of lake waters and metallic pollution in European Russia (ER) and Western Siberia (WS), based on a survey of 367 lakes from the tundra to the steppe zones. The content of more than 80 elements in the lake water was studied; the influence of airborne contamination and the geochemistry of water were estimated. We found that the concentrations of alkaline and alkaline-earth elements, as well as As, V, Co, U, Nb, Sb, increase with a change in the climatic gradient. This fact is explained not only by airborne contamination, but also by the geochemistry of lakes and the climatic factor (increased evaporation concentration). Anthropogenic eutrophication leads to an increase in the content of Fe, Sr, Mo, and acidification—Zn, Cd, Ni, Cu, and especially Pb. There are industry-specific influences: the waters of the northern regions of ER are enriched by Ni, Cd, As, Sb and especially Se because of the emissions from copper-nickel smelters. The oil and gas industry (WS) leads to increased concentrations of V, Pb and Mo in water. We assess the metallic pollution status of surface water in the Eurasian region of Russia using an enrichment factor (EF). In surface waters of ER and WS, metal concentrations do not exceed the maximum permissible concentration, but we have established higher concentrations of many elements in the background, including toxic ones. Prolonged low doses of toxic elements can be a potential hazard to ecosystems and humans. The results showed that from the northern to the southern regions the EF increases for most of the analyzed elements. It can be assumed that with climate warming the concentration of metals in these bodies of water will increase and this is dangerous for the environment.

Assessment of Soil-Water Composition Dynamics in the North Taiga Forests upon the Reduction of Industrial Air Pollution by Emissions of a Copper—Nickel Smelter

This work is aimed at assessing the dynamics of the composition of soil waters in coniferous forests subjected to air pollution from the Severonikel’ copper-nickel smelter in Murmansk oblast. The objects of investigations are the most common in boreal zone spruce forests with dwarf shrubs + green mosses and pine forests with dwarf shrubs + lichens. The results show a significant intra- (below the crowns and between the crowns) and interbiogeocenotic (spruce and pine forests) variation in the composition of atmospheric deposition and soil waters in forests under pollution. The atmospheric deposition of pollutants and leaching of their compounds from all soil genetic horizons are tens (sulfates) and hundreds (copper and nickel) times higher than in reference sites and their fluxes below the crowns are usually more intense than between the crowns. Long-term dynamics (from 1993 to 2012) demonstrate reliable trends in the reduction of concentrations and leaching of sulfates and heavy metals from the soil. The molar ratio of basic cations to aluminum (BC/Al) in soil waters from all soil horizons does not drop to the level of critical, whereas for mineral nitrogen the lowest critical level (0.2 mg/L) was exceeded in waters from all horizons at all stages of digression. It was shown that, for the early detection of exceedances of the critical level for mineral nitrogen in soil waters, an evaluation of their composition is necessary not only between the crowns, but also below them.

Assessment of Soil Water Composition Dynamics in the North Taiga Forests at Reduction of Industrial Air Pollution by Emissions of Copper-Nickel Smelters

Assessment of Soil Water Composition Dynamics in the North Taiga Forests at Reduction of Industrial Air Pollution by Emissions of Copper-Nickel Smelters

Biogeochemistry of Cadmium: Anthropogenic Dispersion, Bioaccumulation, and Ecotoxicity

The article considers biogeochemical features of cadmium as one of the most dangerous elements. Data on its concentrations in waters of small lakes in the European Russia (from the tundra to deserts) and large river systems (Volga, Severnaya Dvina, Pechora) are given. It is shown that, despite the relatively low concentrations of the element in waters, its enrichment factor is hundreds and thousands of units, especially in the northern regions and regions subjected to the influence of non-ferrous metallurgy. Data are presented on the bioaccumulation of cadmium within fish body systems, which is determined by the concentration of the element in waters, as well as by the water pH and the calcium content. It is proved that the highest Cd concentrations are accumulated in kidneys and liver of whitefish and salmon, causing pathological disturbances. Data are reported on the accumulation of cadmium in kidneys and liver of human population of the industrially developed Northern region under impacts of copper–nickel smelters. The similarity in tendencies of the Cd accumulation and pathological disturbances in fish and the population consuming water from contaminated sources makes it possible to recommend fish as a bioindicator of the environmental pollution by cadmium.

Leaves, berries and herbivorous larvae of bilberry Vaccinium myrtillus as sources of metals in food chains at a Cu-Ni smelter site

Ericaceous dwarf shrubs, such as bilberry, Vaccinium myrtillus, have an important role in nutrient cycling of boreal forests, but in metal polluted environments they also form a link between heavy metal pool of the soil, primary consumers and upper trophic levels. From the viewpoint of metal transfer in a food chain, we document metallic element (As, Ca, Cd, Co, Cu, Mn, Mo, Ni, Pb, Se, Zn) concentrations in leaves, berries and herbivorous larvae of V. myrtillus around a Finnish copper-nickel smelter and compare those with levels in relatively unpolluted reference sites, and with levels documented in soil and feces (a proxy of dietary levels) of an insectivorous bird, the pied flycatcher, Ficedula hypoleuca. Herbivorous larvae of the autumnal moth, Epirrita autumnata (Lepidoptera: Geometridae), grown experimentally on V. myrtillus, showed slower growth rate but not higher mortality in the polluted area. In general, metal levels in leaves, berries and larvae were higher in the polluted area and comparable to those reported at other smelter sites in Europe. The levels of the main toxic metals (As, Cd, Cu, Ni, Pb) followed the general pattern: soil > bird feces > leaves > larvae = berries, and levels in V. myrtillus, E. autumnata and F. hypoleuca reflected soil metal levels. The lowest levels were found in those matrices that are most important sources of food for birds and humans, i.e. leaf-eating larvae and berries, reducing a risk of toxic effects.

Monitoring of Soil Contamination by Heavy Metals in the Impact Zone of Copper-Nickel Smelter on the Kola Peninsula

The results of landscape monitoring of the concentrations of acid-extractable Ni, Cu, Co, Mn, and Zn in soils of the local impact zone of the Severonikel industrial complex on the Kola Peninsula are discussed. The aim of monitoring studies was to reveal the spatial and temporal regularities of variation in the degree of soil contamination by heavy metals. In 2001–2011, the concentrations of acid-extractable compounds of the elements in the upper part of organic soil horizons around this plant exceeded their background concentrations by two orders of magnitude for Cu and Co and by three orders of magnitude for Ni. The degree of topsoil contamination with Ni, Cu, and Co generally corresponded to the distance of the plots from the contamination source and to the modern technogenic load. However, because of the long period of the emissions, their extreme amounts, and complex composition, indirect factors—the degree of technogenic soil degradation, the loss of soil organic matter, saturation of the surface soil layers by the contaminating metals, and competitive relationships between the elements—also affect soil contamination level. The concentrations of all the studied metals in the topsoil are characterized by considerable (1.5 to 7 times) variability in their long-term dynamics. The most important factors of this variability for Ni, Cu, and Co are the organic matter content of the samples and the amount of atmospheric precipitation in the year preceding the sampling. An inverse relationship between element concentrations in the soils and the amount of atmospheric precipitation attests to the dynamic nature and reversible character of the accumulation of heavy metals in the soils.

Rehabilitation of Industrial Barren in Arctic Region Using Mining Wastes

Background: This work has explored the possibility of applying mining waste-based ameliorants for the remediation of soil that has been transformed by copper-nickel smelter emissions by means of forming artificial phytocenosis. Objective: The aim of our work was to propose, develop and approbate a technique for the preservation of dumps polluted by heavy metals and prevention of their erosion by creating dense grass covers with the use of wastes from mining and processing enterprises to form a supporting substrate for herbaceous plants. Methods: The vegetative cover was cultivated on a supporting medium, consisting of mining waste, with a hydroponic vermiculite substrate and a mix of graminaceous plant seeds, indigenous to the study area and resistant to heavy metal pollution. The mining wastes, used in the experiment, contained acid-neutralizing minerals such as calcium and magnesium carbonate and hydrous magnesium silicate. Results: It is shown that, due to a large pool of Ca and Mg, these mineral substrates are alkaline (pH 8.4 – 9.2) and can perform successfully in optimizing of edaphic conditions for the plant communities grown on industrial barrens. In a pilot experiment without a proposed supporting medium, the plants did not form a stable grass cover and had died out by the beginning of the third growing season, whereas the experimental plots with a proposed supporting medium (waste-based substrate) developed a high-quality grass cover by the end of second vegetation seasons. Conclusion: The resulting plant communities grown on a proposed supportive medium is find to be resistant to aerotechnogenic pollutants and capable of independent survival, representing the initial stage of progressive succession in the presence of on-going pollution.

Influence of emission from copper–nickel smelters on the chemical composition of lake water: Acidification forecast

The influence of the emission of sulfur dioxide and solid substances from Pechenganickel and Severonickel copper–nickel combines (Murmansk oblast) on the chemical compositions of lake water and the development of acidification is analyzed. The temporal dynamics of ∼100 lakes, studied in 1990, 1995, 2000, 2005, 2009, and the response of the chemical composition of the lake water to the impact of acid-forming substances depending on the load level (the distance of combines), geologically controlled sensitivity of catchment areas of the lakes studied to acid deposition, and the lake areas is discussed. The likely further changes in sulfate concentration and pH value in the lake water under the scenarios of increase/decrease of sulfur dioxide emissions from smelter are estimated.

Polluted environment does not speed up age-related change in reproductive performance of the Pied Flycatcher

Environmental pollution can exacerbate deterioration in fecundity with advancing age, directly via the toxic effects of pollutants or indirectly via pollution-related resource (e.g. dietary antioxidants) constraints. Since there are very few studies on age-related changes in reproduction with regard to pollution, we analyzed a long-term (25 years) set of reproduction data from a small insectivorous and migratory passerine bird, the Pied Flycatcher Ficedula hypoleuca, to determine whether female birds showed a faster age-related decrease in average breeding parameters in a metal-polluted area around a copper–nickel smelter than in the control area. In our population-level analysis, all the breeding parameters (clutch size, hatching success, fledging probability, and fledgling number) were lower in the polluted area. Nevertheless, none of them indicated a faster decrease with age in the polluted area. Clutch size and fledgling number increased after the first breeding, but showed no significant change later on. Hatching probability decreased slightly after the second breeding, while fledging probability showed no significant age-dependent variation. Our results suggest that moderate long-term pollution does not reduce the viability of our study population via a faster age-related decrease in fecundity.