Monographs of the Boreal Environment Research


Sarja sisältää tieteellisen Boreal Environment Research -sarjan monografiat, pääasiassa SYKEn väitöskirjoja.

Publications in this series are mainly dissertations of the Finnish Environment Institute.

Serien innehåller för det mesta doktorsavhandlingar av Finlands miljöcentral.

Uusimmat julkaisut

  • Asmala, Eero (Suomen ympäristökeskus, 2014)
    Monographs of the Boreal Environment Research No. 45
    The pool of riverine dissolved organic matter (DOM) results from integration of complex catchment processes, and links the terrestrial and coastal systems by transporting organic matter from watersheds to estuaries. In this thesis, field samplings and laboratory experiments were combined to assess the spatio-temporal variation in riverine DOM quantity and quality in three Finnish estuaries discharging to the Baltic Sea. Also, the biogeochemical transformation and removal processes influencing the composition of the DOM pool were studied. Large-scale catchment characteristics were linked to the properties of the riverine DOM. Throughout the work the DOM quality was assessed using multiple analytical approaches: C/N stoichiometry, colored DOM (CDOM) absorption, CDOM fluorescence, molecular weight and iron content. Estuarine DOM was subjected to heterotrophic degradation in factorial experiments to quantify the role of salinity, inorganic nutrients and predegradation to DOM bioavailability. Additionally salt-induced flocculation of DOM was studied by combining field samplings, laboratory experiments and modeling. The selected three study catchments differed markedly in their land-use, and these differences were reflected on the riverine DOM quantity and quality. The experiments provided evidence that increasing proportion of forests and peatlands were linked to the increase of carbon loading from the catchment, and to decreases in the subsequent quantities of bioavailable dissolved organic carbon (DOC) and bacterial growth efficiencies (BGE). A higher proportion of agricultural land in the catchment indicated an increase of the amount and bioavailability of dissolved organic nitrogen (DON) in the DOM pool. A larger proportion of lakes in the catchments were related to decreased bioavailable DON. Replete inorganic nutrients did not influence the DOM bioavailability, although did increase BGE on average from 11 to 40%. Increasing predegradation, i.e. DOM subjected to heterotrophic degradation for varying times before the actual bioassays, decreased BGE from 65 to 25% on average. Flocculation caused deviations from conservative mixing of DOM variables in the study estuaries, and the quantity and quality of flocculated DOM was studied in a laboratory experiment. The maximum deviation from conservative mixing of DOC in estuaries was -16% at salinities between 1 and 2, indicating significant flocculation within a relatively narrow salinity range. Both processes, biodegradation and flocculation, removed riverine DOM before reaching the open sea (so-called marginal filter), but also changed the properties of the remaining DOM pool. Also, both processes increased the humic-like fluorescence and DOC-specific absorbance of the DOM pool, which suggests that the refractory DOM pool reaching the sea is a result of multiple, interacting processes along the hydrological path. All in all, both biodegradation and flocculation remove riverine DOM in estuaries, and also transform the remaining DOM pool that ultimately reaches the open sea. Findings from this thesis show that DOM quality has a pivotal role in the functioning of both of these essential and ubiquitous mechanisms.
  • Fronzek, Stefan (Suomen ympäristökeskus, 2013)
    Monographs of the Boreal Environmental Research No. 44
    Palsas are mounds with a permafrost core covered by peat. They occur in subarctic palsa mires, which are ecologically valuable mire complexes located at the outer margin of the permafrost zone. Palsas are expected to undergo rapid changes under global warming. This study presents an assessment of the potential impacts of climate change on the spatial distribution of palsa mires in northern Fennoscandia during the 21st century. A large ensemble of statistical climate envelope models was developed, each model defining the relationship between palsa occurrences and a set of temperature- and precipitation-based indicators. The models were used to project areas suitable for palsas in the future. The sensitivity of these models to changes in air temperature and precipitation was analysed to construct impact response surfaces. These were used to assess the behaviour of models when extrapolated into changed climate conditions, so that new criteria, in addition to conventional model evaluation statistics, could be defined for determining model reliability. A special focus has been on comparing alternative methods of representing future climate, applying these with impact models and quantifying different sources of uncertainty in the assessment. Climate change projections were constructed from output of coupled atmosphere-ocean general circulation models as well as finer resolution regional climate models and uncertainties in applying these with impact models were explored. New methods were developed to translate probabilistic climate change projections to probabilistic estimates of impacts on palsas. In addition to future climate, structural differences in impact models appeared to be a major source of uncertainty. However, using the model judged most reliable according to the new criteria, results indicated that the area with suitable climatic conditions for palsas can be expected to shrink considerably during the 21st century, disappearing entirely for an increase in mean annual air temperature of 4°C relative to the period 1961-1990. The risk of this occurring by the end of the 21st century was quantified to be between 43% (for the B1 low emissions scenario) and 100% (for the A2 high emissions scenario). The projected changes in areas suitable for palsas are expected to have a significant influence on the biodiversity of subarctic mires and are likely to affect the regional carbon budget.
  • Metsämäki, Sari (Suomen ympäristökeskus, 2013)
    Monographs of the Boreal Environment Research 43
    This thesis focuses on the determination of fractional snow cover (FSC) from optical data provided by satellite instruments. It describes the method development, starting from a simple regionally applicable linear interpolation method and ending at a globally applicable, semi-empirical modeling approach. The development work was motivated by the need for an easily implementable and feasible snow mapping method that could provide reliable information particularly for forested areas. The contribution of the work to the optical remote sensing of snow is mainly associated with accounting for boreal forest canopy effect to the observed reflectance, thus facilitating accurate fractional snow retrievals also for ground beneath the tree canopies. The first proposed approach was based on a linear interpolation technique, which relies on a priori known reference reflectances at a) full snow cover and b) snow-free conditions for each calculation unit-area. An important novelty in the methodology was the utilization of a forest sparseness index determined from AVHRR reflectance data acquired at full dry snow cover conditions. This index was employed to describe the similarity between different unit-areas. In practice, the index was used to determine the reference reflectances for such unit-areas for which the reflectance level could not be determined otherwise, e.g. due to frequent cloud cover. This approach was found to be feasible for Finnish drainage basins characterized by fragmented landscape with moderate canopies. Using a more physical approach instead of linear interpolation would allow the model parameterization using physical quantities (reflectances), and would therefore leave space for further model developments based on measuring and/or modeling of these quantities. The semi-empirical reflectance model-based method SCAmod originates from radiative transfer theory and describes the scene-level reflectance as a mixture of three major constituents: opaque forest canopy, snow and snow-free ground, which are interconnected through transmissivity and snow fraction. Transmissivity, in turn, can be derived from reflectance observations under conditions that highlight the presence of forest canopy, namely the presence of full snow cover on the ground. Thus, SCAmod requires a priori information on transmissivity, but given that it can be determined with the appropriate accuracy, it enables consideration of the obstructing effects of forests in fractional snow estimation. In continental-scale snow mapping, determination of the transmissivity map becomes a key issue. The preliminary demonstration of transmissivity generation using global land cover data was a part of this study. The first implementations and validations for SCAmod were presented for AVHRR data at Finnish drainage basin scale. In subsequent work, determination of the feasible reflectance constituents was addressed, followed by a sensitivity analysis targeting at selection of optimal spectral bands to be applied with SCAmod. Feasibility of the NDSI-based approach in FSC-retrievals over boreal forests is also discussed. Finally, the implementations and validations for MODIS and AATSR data are presented. The results from relative (using high-resolution Earth Observation data to represent the truth) and absolute validation (using in situ observations) indicate a good performance for both forested and non-forested regions in northern Eurasia. Accounting for the effect of forest canopy in the FSC-retrievals is the key issue in snow remote sensing over boreal regions; this study provides a new contribution to this research field and provides one solution for continental scale snow mapping.
  • Lipponen, Annukka (Finnish Environment Institute, 2006)
    Monographs of the Boreal Environment Research 25
    The main objective of this study is to evaluate selected geophysical, structural and topographic methods on regional, local, and tunnel and borehole scales, as indicators of the properties of fracture zones or fractures relevant to groundwater flow. Such information serves, for example, groundwater exploration and prediction of the risk of groundwater inflow in underground construction. This study aims to address how the features detected by these methods link to groundwater flow in qualitative and semi-quantitative terms and how well the methods reveal properties of fracturing affecting groundwater flow in the studied sites. The investigated areas are: (1) the Päijänne Tunnel for water-conveyance whose study serves as a verification of structures identified on regional and local scales; (2) the Oitti fuel spill site, to telescope across scales and compare geometries of structural assessment; and (3) Leppävirta, where fracturing and hydrogeological environment have been studied on the scale of a drilled well.The methods applied in this study include: the interpretation of lineaments from topographic data and their comparison with aeromagnetic data; the analysis of geological structures mapped in the Päijänne Tunnel; borehole video surveying; groundwater inflow measurements; groundwater level observations; and information on the tunnel's deterioration as demonstrated by block falls. The study combined geological and geotechnical information on relevant factors governing groundwater inflow into a tunnel and indicators of fracturing, as well as environmental datasets as overlays for spatial analysis using GIS. Geophysical borehole logging and fluid logging were used in Leppävirta to compare the responses of different methods to fracturing and other geological features on the scale of a drilled well.Results from some of the geophysical measurements of boreholes were affected by the large diameter (gamma radiation) or uneven surface (caliper) of these structures. However, different anomalies indicating more fractured upper part of the bedrock traversed by well HN4 in Leppävirta suggest that several methods can be used for detecting fracturing.Fracture trends appear to align similarly on different scales in the zone of the Päijänne Tunnel. For example, similarities of patterns were found between the regional magnetic trends, correlating with orientations of topographic lineaments interpreted as expressions of fracture zones. The same structural orientations as those of the larger structures on local or regional scales were observed in the tunnel, even though a match could not be made in every case. The size and orientation of the observation space (patch of terrain at the surface, tunnel section, or borehole), the characterization method, with its typical sensitivity, and the characteristics of the location, influence the identification of the fracture pattern. Through due consideration of the influence of the sampling geometry and by utilizing complementary fracture characterization methods in tandem, some of the complexities of the relationship between fracturing and groundwater flow can be addressed.The flow connections demonstrated by the response of the groundwater level in monitoring wells to pressure decrease in the tunnel and the transport of MTBE through fractures in bedrock in Oitti, high­light the importance of protecting the tunnel water from a risk of contamination. In general, the largest values of drawdown occurred in monitoring wells closest to the tunnel and/or close to the topographically interpreted fracture zones. It seems that, to some degree, the rate of inflow shows a positive correlation with the level of reinforcement, as both are connected with the fracturing in the bedrock.The following geological features increased the vulnerability of tunnel sections to pollution, especially when several factors affected the same locations: (1) fractured bedrock, particularly with associated groundwater inflow; (2) thin or permeable overburden above fractured rock; (3) a hydraulically conductive layer underneath the surface soil; and (4) a relatively thin bedrock roof above the tunnel. The observed anisotropy of the geological media should ideally be taken into account in the assessment of vulnerability of tunnel sections and eventually for directing protective measures.
  • Alhola, Katriina (Finnish Environment Institute, 2012)
    Monographs of the Boreal Environment Research 40
    Green public procurement (GPP) is about setting environmental criteria in the public procurement process alongside the traditional purchasing criteria, e.g. price, quality and technical features of products, services and works. GPP is considered to be one of the key policies that could be used to promote the change of unsustainable patterns of consumption and production.The use of environmental procurement criteria has increased during this decennium, as it has been promoted by many international and national policies and programmes. Nevertheless, how does this push for greener public procurement comply with the primary aims of public procurement legislation – guaranteeing the best value for taxpayers’ money and the operability of the internal market? The challenge is to combine economic and environmental issues so that purchasing decisions are compliant with law and jurisprudence. In this thesis, this issue is analyzed by examining the relations of environmental and economic aspects as well as environmental and legal aspects in public procurement.This thesis uses several methods and tools to assess the greenness of public procurement; an analysis of purchasing criteria, life cycle assessment and eco-label criteria. Environmental criteria found in the tender documents are mirrored to the existing European procurement directives and case law. The relation between economy and environment is studied within the concept of the most economically advantageous tender as defined in the EU’s public procurement directives. Its content and applicability in the assessment of economic and environmental performance of a purchase is opened for discussion.The results of this thesis suggest that economical, environmental and legal aspects can be combined in public procurement, though the linking of green criteria is specific to a single contract. Despite the increased amount of green criteria in tender documents (i.e. calls for tenders and contracts), they mainly focus on those aspects that are undoubtedly covered by the procurement directives – possibly excluding some of the important environmental impacts of the product or service from a life cycle perspective. However, systematically presented green criteria in calls for tenders could give a signal to the manufacturers of the demand for environmentally preferable solutions, and encourage them to invest in developing green products, i.e. eco-design.
  • Ahtiainen, Jukka (Finnish Environment Institute, 2002)
    Monographs of the Boreal Environment Research 22
    New chemicals are produced in increasing numbers. In Finland every year about 28 000 different products are manufactured or imported which can be classified as harmful. These products contain about 5000 different harmful substances. We also receive harmful compounds in airborne emissions. Substances are further transformed in industrial processes, in waste management and in the environment by human activities and natural processes. However, only rather limited monitoring data is available about the environmental concentrations of these compounds (concerning about 20–40 substances). The environmental risks of harmful substances can be recognized, assessed and managed by : 1) measuring concentrations in the environment, 2) testing the effects on biota in toxicity tests and 3) monitoring ecosystem changes in the environment. Microbes have a key role in the environment as degraders in the carbon and nutrient cycles. They also have the capability to transform and degrade many harmful man-made substances. Microbes have a strong effect on the exposure of other biota to chemical substances. Hence they can be regarded as primary targets for harmful effects of chemicals or active transformers of chemicals in the environment.The objective of this study was to evaluate the usefulness and applicability of microbial toxicity tests, biodegradation tests and microbial biomass and activity measurements in the environment for the environmental hazard identification and risk assessment of chemicals, effluents and contaminated soils. The study considers both aquatic and soil environments. The effects of modern pulp mill bleaching effluents on biota were assessed by a set of different biotests and by chemical analysis. The effluents and their long term effects on aquatic microbial processes were also studied in outdoor mesocosms. In one part the biodegradation kinetics of carbon-14-labeled model compounds in standard tests and in environmental conditions were measured and compared. The effects of several pesticides on soil microbes were tested and assessed in laboratory tests and in field trials. The applicability of microbial toxicity tests in the assessment of soil pollution and bioremediation processes was also studied in comparison with chemical analysis. The results of the study can support the development and selection of test methods for environmental risk management and regulatory decisions.
  • Mannio, Jaakko (Finnish Environment Institute, 2001)
    Monographs of the Boreal Environment Research 18
    The present work provides a national scale assessment of the trace metal contamination of small headwater lakes and the recent development of acidified lakes in Finland. The information is needed as a scientific basis for further actions in air pollution policy. The study is based on observations in a national monitoring network of lake acidification.Anthropogenic, atmospheric deposition is primarily responsible for the increase of Cd, Hg, Pb and As in headwater lake sediments. However, a decline of 20 to 40% of the accumulation of these elements within the last decades was observed, indicating a relatively fast response to the decline in the atmospheric deposition, and that the accumulated stores of atmospheric trace metals in the catchment soils are not dominating the supply of trace elements to lakes.Lake waters reflected atmospheric trace metal pollution as well, but it was not as clearly quantifiable. Acidity controls in particular the level of Cd and Zn, while organic matter (humus) controls more the level of Cr, Fe, Cu and Ni in headwater lakes. Lead, Mn and Al concentrations are affected by both these factors. Humus acts as a carrier for trace metals from catchments soils to surface waters, irrespectively of their original source.Based on comparable chemical data sets, the risks of biological effects in lakes due to trace metals are lower in Finland than in Sweden and Norway. Trace metal levels in lake waters are less critical for the biota than acidity and inorganic (labile) aluminium levels.Due to acidification, there where estimated to be 2200-4400 damaged fish populations in southern and central Finland. Most of these populations are roach in lakes smaller than ten hectares. Sulphate concentrations have declined in all types of small lakes throughout Finland in the 1990s, indicating a clear response to the sulphur emission reductions. Base cation concentrations are still declining in lakes especially in southern Finland, but to a lesser extent than sulphate.There are presently no indications of elevated nitrate levels in forested headwater lakes. The increase in buffer capacity (chemical recovery) was relatively uniform throughout the country, except that the changes were not as significant statistically and by magnitude in the dilute lakes in northern Finland.Nearly 5000 headwater lakes larger than four hectares were estimated to be recovering from acidification at present. The chemical conditions were found to be improving throughout Finland, and first perch population recoveries in southern Finland were observed.The monitoring and survey results presented here are an example of an approach, where both spatial and temporal data from several sources are aggregated. This facilitates the estimation of regional changes and quantifies the changes on national scale. The consistent monitoring provides also sound basis for further modelling of recovery processes and scenario assessment.A new challenge is the interaction of acidification/recovery processes and trace metals with possible trends in temperature and hydrology due to global climate change. This should be taken into account when assessing long-term surface water quality and developing future monitoring networks. Empirical data in space and time is needed to judge, whether the emission reduction measures have been efficient.
  • Hildén, Mikael; Lepola, Jukka; Mickwitz, Per; Mulders, Aard; Palosaari, Marika; Similä, Jukka; Sjöblom, Stefan; Vedung, Evert (Finnish Environment Institute, 2002)
    Monographs of the Boreal Environment Research 21
    This research-based evaluation of environmental policy Instruments in Finland is focussed on regulatory instruments based on the Water Act, the Air Pollution Control Act and the Chemicals Act, on electricity taxation and on voluntary environmental management systems. The examined policy instruments have had several positive effects. They have directed major industrial point source polluters towards solving environmental problems. The transparency has been an important factor ensuring the success of the policy instruments and in avoiding the regulatory capture that could have thrived in a system largely based on negotiations between operators and authorities. The transparency has made it easy for Finnish firms to adopt environmental management systems and an open attitude to environmental reporting. The permit conditions have not directly resulted in innovations, but they have contributed to the diffusion of end-of-pipe technology and have contributed to innovations by expanding the market for environmentally better technical solutions. The permit systems have also indirectly contributed to innovations by creating a demand for environmental experts and environmental education.Networks have clearly developed as a consequence of and in response to regulatory instruments. These networks appear to have had their greatest significance prior to the permit procedures. The trend has been towards a greater emphasis of the communication in the networks prior to the presentation of an application in order to ensure a smoothly functioning permit process. In the networks contributing to innovations and the diffusion of innovations authorities have largely been outsiders, except when an innovation has become a de facto standard for permit conditions.The different kind of effects, the complexity of consequences and the uncertainties with respect to causes and effects mean that studies aiming at evaluating the overall worth and merit of an environmental policy instrument should never be structured from a single point of view using only one method. Multiple criteria should be used. The drawback of the multiple approach principle in evaluation is that the evaluations will run into data problems and all the difficulties of multi- and transdisciplinary research, but the multidisciplinarity is a necessary condition for developing an informed view of the functioning and effects of environmental policy instruments.This publication is the result of a project financed by the environmental cluster research programme.
  • Antikainen, Riina (Finnish Environment Institute, 2007)
    Monographs of the Boreal Environment Research 27
    Nitrogen (N) and phosphorus (P) are essential elements for all living organisms.However, in excess, they contribute to such environmental problems as aquatic and terrestrial eutrophication (N, P), acidification (N), global warming (N), groundwater pollution (N), depletion of stratospheric ozone (N), formulation of tropospheric ozone (N) and poor urban air quality (N). Globally, human action has multiplied the volume of N and P cycling since the onset of industrialization. Themultiplication is a result of intensified agriculture, increased energy consumption and population growth. Industrial ecology (IE) is a discipline, inwhich human interactionwith the ecosystems is investigated using a systems analytical approach. The main idea behind IE is that industrial systems resemble ecosystems, and, like them, industrial systems can then be described using material, energy and information flows and stocks. Industrial systems are dependent on the resources provided by the biosphere, and these two cannot be separated from each other. When studying substance flows, the aims of the research from the viewpoint of IE can be, for instance, to elucidate theways howthe cycles of a certain substance could be more closed and how the flows of a certain substance could be decreased per unit of production (= dematerialization). IE uses analytical research tools such as material and substance flow analysis (MFA, SFA), energy flow analysis (EFA), life cycle assessment (LCA) and material input per service unit (MIPS). In Finland, N and P are studied widely in different ecosystems and environmental emissions. A holistic picture comparing different societal systems is, however, lacking. In this thesis, flows of N and P were examined in Finland using SFA in the following four subsystems: I) forest industry and use of wood fuels, II) food production and consumption, III) energy, and IV) municipal waste. A detailed analysis at the end of the 1990s was performed. Furthermore, historical development of the N and P flows was investigated in the energy system (III) and the municipal waste system (IV). The main research sources were official statistics, literature, monitoring data, and expert knowledge. The aim was to identify and quantify the main flows of N and P in Finland in the four subsystems studied. Furthermore, the aim was to elucidate whether the nutrient systems are cyclic or linear, and to identify how these systems could be more efficient in the use and cycling of N and P. A final aim was to discuss how this type of an analysis can be used to support decision-making on environmental problems and solutions. Of the four subsystems, the food production and consumption system and the energy system created the largest N flows in Finland. For the creation of P flows, the food production and consumption system (Paper II) was clearly the largest, followed by the forest industry and use of wood fuels and the energy system. The contribution of Finland to N and P flows on a global scale is low, but when compared on a per capita basis, we are one of the largest producers of these flows, with relatively high energy and meat consumption being the main reasons. Analysis revealed the openness of all four systems.The openness is due to the high degree of internationality of the Finnish markets, the large-scale use of synthetic fertilizers and energy resources and the low recycling rate ofmanywaste fractions. Reduction in the use of fuels and synthetic fertilizers, reorganization of the structure of energy production, reduced human intake of nutrients and technological development are crucial in diminishing the N and P flows. To enhance nutrient recycling and replace inorganic fertilizers, recycling of such wastes as wood ash and sludge could be promoted. SFAis not usually sufficiently detailed to allow specific recommendations for decision-making to bemade, but it does yield useful information about the relative magnitude of the flows and may reveal unexpected losses. SFA studies should be supported with other methods such as LCA. Data uncertainties are high in this type of analysis. Use of quantitative uncertainty analysis is therefore recommended. Definition of the system boundaries significantly affects conclusions drawn from SFA results. Sustainable development is a widely accepted target for all human action. SFA is one method that can help to analyse how effective different efforts are in leading to a more sustainable society. SFA?s strength is that it allows a holistic picture of different natural and societal systems to be drawn. Furthermore, when the environmental impact of a certain flow is known, the method can be used to prioritize environmental policy efforts.
  • Lyytimäki, Jari (Finnish Environment Institute, 2012)
    Monographs of the Boreal Environment Research 42
    Media representations are an important part of the dynamics of contemporary socio-ecological systems. The media agenda influences and interacts with the public and the policy agenda and all of these are connected to the changes of the state of the environment. Partly as a result of media debate, some issues are considered serious environmental problems, some risks are amplified while others are attenuated, and some proposals for remedies are highlighted and others downplayed. Research on environmental media coverage has focused predominantly on the English-speaking industrialised countries. This thesis presents an analysis of Finnish environmental coverage, focusing on representations of climate change and eutrophication from 1990–2010. The main source of material is Helsingin Sanomat (HS), the most widely-read newspaper in Finland. The analysis adopts the perspective of contextual constructivism and the agenda-setting function of the mass media. Selected models describing the evolution of environmental coverage are applied within an interdisciplinary emphasis. The results show that the amount of newspaper content on eutrophication and climate change has generally increased, although both debates have been characterised by intense fluctuations. The volume of the coverage on climate change has been higher than that of eutrophication, especially since 2006. Eutrophication was highlighted most during the late 1990s while the peaks of climate coverage occurred between 2007 and 2009. Two key factors have shaped the coverage of eutrophication. First, the coverage is shaped by ecological factors, especially by the algal occurrences that are largely dependent on weather conditions. Second, the national algal monitoring and communication system run by environmental authorities has provided the media with easy-to-use data on the algal situation during the summertime. The peaks of climate coverage have been caused by an accumulation of several contributing factors. The two most important factors contributing to the increase in coverage since 2006 include international policy negotiations and mild and snowless winters. Between 2006 and 2008, other factors included the releases of major scientific reviews, expressions of concern by key actors, and the related debate on energy policy. Changes in the anthropogenic driving forces of the environmental changes, namely nutrient discharges and greenhouse gas emissions, had only a marginal impact on the level of coverage. Based on the results, it is suggested that wide-ranging climate reporting has caused what has been called a piercing effect. This means that after the phase of intense and widespread media coverage, climate issues will not disappear but will shift from highly visible environmental headlines to less visible but more pervasive background information presented in various contexts. Such a piercing effect was not identified for eutrophication. This thesis highlights the importance of taking media coverage into account as a key factor in the formulation and implementation of environmental policies aimed at broad-based actions.
  • Vuorenmaa, Jussi (Finnish Environment Institute, 2007)
    Monographs of the Boreal Environment Research 30
    The present work provides a regional-scale assessment of the changes in acidifying deposition in Finland over the past 30 years and the current pattern in the recovery of acid-sensitive lakes from acidification in relation to changes in sulphate deposition. This information is needed for documenting the ecosystem benefits of costly emission reduction policies and further actions in air pollution policy. The development of sulphate deposition in Finland reflects that of European SO2 emissions. Before the 1990s, reductions in sulphur emissions in Europe had been relatively small and sulphate deposition showed no consistent trends. Due to emission reduction measures that were then taken, sulphate deposition started to clearly decline from the late 1980s. The bulk deposition of sulphate has declined 40-60% in most parts of the country during 1990-2003. The decline in sulphate deposition exceeded the decline of base cation deposition, which resulted in a decrease in acidity and acidifying potential of deposition over the 1990s. Nitrogen deposition also decreased since the late 1980s, but less than that of sulphate, and levelling off during the 1990s. Sulphate concentrations in all types of lakes throughout Finland have declined from the early 1990s. The relative decrease in lake sulphate concentrations (average 40-50%) during 1990-2003 was rather similar to the decline in sulphate deposition, indicating a direct response to the reduction in deposition. There are presently no indications of elevated nitrate concentrations in forested headwater lakes. Base cation concentrations are still declining in many lakes, especially in south Finland, but to a lesser extent than sulphate allowing buffering capacity (alkalinity) to increase. The recovery has been strongest in lakes in which sulphate has been the major acidifying agent, and recovery has been the strongest and most consistent in lakes in south Finland. The recovery of lakes in central Finland and north Finland is not as widespread and strong as observed in south. Many catchments, particularly in central Finland, have a high proportion of peatlands and therefore high TOC concentrations, and runoff-induced surges of organic acids have been an important confounding factor suppressing the recovery of pH and alkalinity in these lakes. Chemical recovery is progressing even in the most acidified lakes, but the buffering capacity of many lakes is still low and still sensitive to acidic input. Chemical recovery is resulting in biological recovery with populations of acid-sensitive fish species increasing. Increasing TOC concentrations are indicated in small forest lakes in Finland, which appear to be related to decreasing sulphate deposition and improved acid-base status of the soil. A new challenge is climate change with potential trends in temperature, precipitation and runoff, which are expected to affect future chemical and biological recovery from acidification. The potential impact of mobilization and leaching of organic acids may become particularly important in Finnish conditions. Long-term environmental monitoring has evidently shown the success of international emission abatement strategies. The importance and value of integrated monitoring approach including physical, chemical and biological variables is clearly indicated, and continuous environmental monitoring is needed as a scientific basis for further actions in air pollution policy. The effect of climate change will increase data requirements, and should be taken into account when assessing long-term surface water quality and developing future monitoring networks, due to more complex processes involved.
  • Porvari, Petri (Finnish Environment Institute, 2003)
    Monographs of the Boreal Environment Research 23
    Deposition, catchment runoff concentrations and fluxes, lake water concentrations of total mercury (TotHg) and methyl mercury (MeHg), and potential Hg methylation in different compartments of boreal ecosystem and TotHg concentrations of fish in boreal and tropical reservoirs were studied. The results provide new knowledge of behaviour and cycling of Hg for Hg pollution protection policy. Anthropogenic and natural Hg emissions have led to increased Hg deposition and further accumulation of Hg in soil. A decline of 50% in atmospheric TotHg deposition from the late 1980s to 2000 was observed in southern Finland. During the period of 1995–2000 TotHg and MeHg deposition remained unchanged in southern Finland. The vast storage of Hg in forest soil had a determining role as a source of TotHg and MeHg for forest drainage lakes. Only small variations in TotHg concentrations and output fluxes in runoff waters were detected among the catchments, but clearly the highest MeHg concentrations and output fluxes came from the pure peatland and the lowest from forested upland catchments. This indicates more effective MeHg production in peatlands than in uplands. Silvicultural treatment of a small spruce forest catchment increased significantly the runoff concentrations and export of TotHg and MeHg. The results indicated that clear cutting and soil treatment may significantly increase the mobility of TotHg and MeHg accumulated in forest soil and silvicultural treatment is thus an important factor for the total input of Hg and MeHg to boreal lakes. Flooding of forest soils (humus and peat) released TotHg and MeHg to water column and enhanced Hg methylation. Moreover, Hg methylation process was favoured by anoxic conditions. Flooding of soils on a large scale, i.e. when constructing man-made lakes (reservoirs) caused elevated fish Hg levels through enhanced Hg methylation. Hg accumulation as elevated TotHg concentrations in fish (especially predatory fish) was observed both in boreal (Ostrobothnia and Lapland, Finland) and tropical reservoirs (Amazonia, Brazil). In Brazil, the highest mercury levels were recorded in predatory fish, the intermediate levels in planktivorous and omnivorous fish and the lowest in herbivorous fish. In Finland, even 20 years after flooding, the TotHg concentrations of the predatory fish (northern pike, Esox lucius L.) in some of the reservoirs exceeded the upper limit for fish consumption and in Brazil, 6 years after flooding 92% of all predatory fish sampled exceeded the safety limit for Hg concentrations in fish. The observations from Finnish and Brazilian reservoirs showed that the duration of the phenomenon of Hg contamination of fish in reservoirs may last for 15–30 years. The Hg contamination succession in fish appears to be similar in boreal and tropical reservoirs. The results of this work distinctly indicate the determining role of catchment as a MeHg source to forest lakes. The effects of forestry practices on Hg export emphasise the need for more research on this issue. The long lasting Hg contamination in reservoirs regardless of climatological zone requires restrictions of predatory fish consumption especially where people utilise a large amounts of fish for food.
  • Kauppila, Pirkko (Finnish Environment Institute, 2007)
    Monographs of the Boreal Environment Research 31
    The tackling of coastal eutrophication requires water protection measures based on status assessments of water quality. The main purpose of this thesis was to evaluate whether it is possible both scientifically and within the terms of the European Union Water Framework Directive (WFD) to assess the status of coastal marine waters reliably by using phytoplankton biomass (ww) and chlorophyll a (Chl) as indicators of eutrophication in Finnish coastal waters. Empirical approaches were used to study whether the criteria, established for determining an indicator, are fulfilled.The first criterion (i) was that an indicator should respond to anthropogenic stresses in a predictable manner and has low variability in its response. Summertime Chl could be predicted accurately by nutrient concentrations, but not from the external annual loads alone, because of the rapid affect of primary production and sedimentation close to the loading sources in summer. The most accurate predictions were achieved in the Archipelago Sea, where total phosphorus (TP) and total nitrogen (TN) alone accounted for 87% and 78% of the variation in Chl, respectively. In river estuaries, the TP mass-balance regression model predicted Chl most accurate when nutrients originated from point-sources, whereas land-use regression models were most accurately in cases when nutrients originated mainly from diffuse sources. The inclusion of morphometry (e.g. mean depth) into nutrient models improved accuracy of the predictions.The second criterion (ii) was associated with the WFD. It requires that an indicator should have type-specific reference conditions, which are defined as “conditions where the values of the biological quality elements are at high ecological status”. In establishing reference conditions, the empirical approach could only be used in the outer coastal waters types, where historical observations of Secchi depth of the early 1900s are available. Most accurate prediction was achieved in the Quark. However, the average reference values in the outer coastal types are underestimated in sites near the zone of the inner coastal waters. In the inner coastal water types, reference Chl, estimated from present monitoring data, are imprecise - not only because of the less accurate estimation method - but also because the intrinsic characteristics, described for instance by morphometry, vary considerably inside these extensive inner coastal types. As for phytoplankton biomass, the reference values were less accurate than in the case of Chl, because it was possible to estimate reference conditions for biomass only by using the reconstructed Chl values, not the historical Secchi observations. An paleoecological approach was also applied to estimate reference conditions for Chl. In Laajalahti, an urban embayment off Helsinki, strongly loaded by municipal waste waters until 1986, reference conditions prevailed in the mid- and late 1800s. The recovery of the bay from pollution has delayed as a consequence of benthic release of nutrients. Laajalahti will probably not achieve the good quality objectives of the WFD on time.The third criterion (iii) was associated with coastal management including the resources it has available. Analyses of Chl are cheap and fast to carry out compared to the analyses of phytoplankton biomass and species composition; the fact which has an effect on number of samples to be taken and thereby on the reliability of assessments. However, analyses on phytoplankton biomass and species composition provide more metrics for ecological classification, the metrics which reveal various aspects of eutrophication contrary to what Chl alone does.
  • Sorvari, Jaana (Finnish Environment Institute, 2010)
    Monographs of the Boreal Environment Research 37
    Land contamination is a significant environmental problem requiring systematic management actions. Defining the type and scale of the actions requires information on the risks involved. The numerous methods available for conducting risk assessment (RA) vary in terms of complexity, level of detail, conservatism, and outcomes. Thus, selecting suitable methods requires information on their applicability in Finnish conditions and at the specific site. On the other hand, it is generally accepted that current contaminated land management (CLM) should not only focus on minimizing site-specific risks, but should also consider overall environmental effects and socio-cultural and socio-economic aspects. Multi-Criteria Analysis (MCA) could then be used as a tool for integrating multidimensional data and generating aggregated information on the consequences of different risk management (RM) options, such as environmental, social, and economic impacts. Nonetheless, such approaches have very seldom been applied in CLM in Finland, probably partly due to a lack of tools specifically developed or modified for Finnish conditions.This research studied the application and suitability of different RA methods for assessing risks and identifying RM needs at some typical contaminated sites in Finland and demonstrated the use of MCA, the emphasis being on soil contamination. The studied RA approaches comprised qualitative rating and quantitative methods that were based on using environmental benchmarks, uptake and exposure models, and multimedia software. To derive estimates of ecological risks, the so-called TRIAD procedure that uses chemical studies, bioassays, and ecological studies was also applied and combined with MCA in order to account for the performance of the study methods, i.e. their ability to depict ecological risks at a study site. Qualitative rating and the statistical Monte Carlo technique provided additional means for uncertainty analysis. A separate study applying the Metaplan technique, interviews, a questionnaire, and a literature survey showed that a lack of suitable assessment tools was one of the key barriers to eco-efficient CLM in Finland. An MCA-based decision support tool (DST) adapting the Multi-Attribute Value Theory (MAVT) was therefore developed for case-by-case determination of the preferred RM option and tested with some typical Finnish contaminated sites.Many of the conclusions of the research are overarching and applicable to RA methods in general. Fistly, it appered that care must be taken in applying different models and software tools in site-specific RA, since some of their components are not straightforwardly suitable for Finnish conditions or for certain contaminants. These problems often relate to specific contaminant transport pathways. Moreover, the lack of verified data on the parameter values representative of Finnish conditions is an issue. The prevailing practice of using complicated software programs with ample data demands as the first and primary tools in human health risk assessment is not supported by this research, since it appeared that even simple tools and calculations can often provide adequate information on risks for decision-making. In ecological risk assessment (ERA), the usefulness of the approach founded on uptake and exposure models is reduced by the high uncertainties involved, particularly since the applicability of these models in Finnish conditions could not be verified. The accuracy and reliability of ecological risk estimates can be enhanced by applying the TRIAD methodology, although the procedure includes some pitfalls that need to be acknowledged. Combining TRIAD with MCA proved to be a feasible means to quantitatively study the performance of separate ERA methods. MCA thereby complements mechanical statistical analysis, such as Monte Carlo simulation, and increases the reliability of the final integrated risk estimates. In practice, a lack of data on the statistics of the input variables can restrict the use of statistical tools. The MAVT-based DST turned out to be efficient in facilitating discussion between different interest groups and experts and in identifying the preferred RM option in the common situation where risks are not the only factors relevant in decision-making. In practice, additional factors, such as the temporal scope of RM actions and some sustainability components that were not comprehensively included in the DST, might need to be considered.
  • Auvinen, Ari-Pekka; Hildén, Mikael; Toivonen, Heikki; Primmer, Eeva; Niemelä, Jari; Aapala, Kaisu; Bäck, Saara; Härmä, Pekka; Ikävalko, Jussi; Järvenpää, Elise; Kaipiainen, Heidi; Korhonen, Kari T.; Kumela, Hanna; Kärkkäinen, Leena; Lankoski, Jussi; Laukkanen, Marita; Mannerkoski, Ilpo; Nuutinen, Tuula; Nöjd, Anna; Punttila, Pekka; Salminen, Olli; Söderman, Guy; Törmä, Markus; Virkkala, Raimo (Finnish Environment Institute, 2007)
    Monographs of the Boreal Environment Research 29
    The results of the evaluation of the Finnish National Biodiversity Action Plan 1997-2005 indicate clear changes towards better consideration of biodiversity in the routines and policies of many sectors of the administration and economy. There are many indications that actors across society have recognized the need to safeguard biodiversity and have begun to adjust their practices accordingly. Several concrete measures have been undertaken in forests, agricultural habitats and in other habitats significantly affected by human activities. Biodiversity research has expanded significantly and the knowledge of Finland´s biological diversity has increased. In general, the Action Plan has supported public discussion of the need to safeguard biodiversity and this discussion has resulted in more positive attitudes towards nature conservation.So far, however, the implemented measures have not been sufficiently numerous or efficient to stop the depletion of original biological diversity. Many habitats remain far from their original state. More species will become endangered in the immediate future unless more effective and far-reaching measuresare taken. The objective of the EU to halt the decline of biodiversity by 2010 will not be achieved given the current development. Although the deterioration in biodiversity may have slowed down in several cases, many economic activities continue to have a negative impact on biodiversity. The scale of these activities is normally greater than that of the measures taken to manage and restore biodiversity.The evaluation focused on detecting changes in the administration of key sectors, analysing the recent development of biodiversity and observing interlinkages between these two. The analysis of administrative measures was based on interviews and on examining policy documents, reports and other relevant literature. The analysis covered changes in the administration of nature conservation, forestry,  agriculture, land use and regional and development cooperation. The analysis of the development of biodiversity was based on employing 75 pressure, state, impact and response indicators. There were 5 to 15 indicators for each of the nine major habitat types of Finland.Three separate case studies were made to provide further insights into some key issues: 1) A GISanalysis was made of the development of land use patterns in North Karelia and south-west Finland between 1990 and 2000, 2) two scenarios on the development of forest structure in North Karelia until 2050 were developed using a special MELA-model and 3) the cost-effectiveness of the agri-environmental support scheme was examined by comparing different land allocation choices and their effects on biodiversity on an average farm in southern Finland. The evaluation also paid special attention to the role of research in safeguarding biodiversity and reflected Finnish experiences against an international background.
  • Uronen, Pauliina (Finnish Environment Institute, 2007)
    Monographs of the Boreal Environment Research 28
    This study deals with algal species occurring commonly in the Baltic Sea: haptophyte Prymnesium parvum, dinoflagellates Dinophysis acuminata, D. norvegica and D. rotundata, and cyanobacterium Nodulariaspumigena. The hypotheses are connected to the toxicity of the species, to the factors determining toxicity, to the consequences of toxicity and to the transfer of toxins in the aquatic food web.Since the Baltic Sea is severely eutrophicated, the fast-growing haptophytes have potential in causing toxic blooms. In our studies, the toxicity (as haemolytic activity) of the haptophyte P. parvum was highest under phosphorus-limited conditions, but the cells were toxic also under nitrogen limitation and under nutrient-balanced growth conditions. The cellular nutrient ratios were tightly related to the toxicity. The stoichiometric flexibility for cellular phosphorus quota was higher than for nitrogen, and nitrogen limitation led to decreased biomass. Negative allelopathic effects on another algae (Rhodomonas salina) could be observed already at low P. parvum cell densities, whereas immediate lysis of R. salina cells occurred at P. parvum cell densities corresponding to natural blooms. Release of dissolved organic carbon from the R. salina cells was measured within 30 minutes, and an increase in bacterial number and biomass was measured within 23 h. Because of the allelopathic effect, formation of a P. parvum bloom may accelerate after a critical cell density is reached and the competing species are eliminated. A P. parvum bloom indirectly stimulates bacterial growth, and alters the functioning of the planktonic food web by increasing the carbon transfer through the microbial loop.Our results were the first reports on DSP toxins in Dinophysis cells in the Gulf of Finland and on PTX-2 in the Baltic Sea. Cellular toxin contents in Dinophysis spp. ranged from 0.2 to 149 pg DTX-1 cell-1 and from 1.6 to 19.9 pg PTX-2 cell-1 in the Gulf of Finland. D. norvegica was found mainly around the thermocline (max. 200 cells L-1), whereas D. acuminata was found in the whole mixed layer (max. 7 280 cells L-1). Toxins in the sediment trap corresponded to 1 % of DTX-1 and 0.01 % PTX-2 of the DSP pool in the suspended matter. This indicates that the majority of the DSP toxins does not enter the benthic community, but is either decomposed in the water column, or transferred to higher trophic levels in the planktonic food chain.We found that nodularin, produced by Nodularia spumigena, was transferred to the copepod Eurytemoraaffinis through three pathways: by grazing on filaments of small Nodularia, directly from the dissolved pool, and through the microbial food web by copepods grazing on ciliates, dinoflagellates and heterotrophic nanoflagellates. The estimated proportion of the microbial food web in nodularin transfer was 22-45 % and 71-76 % in our two experiments, respectively. This highlights the potential role of the microbial food web in the transfer of toxins in the planktonic food web.
  • Syri, Sanna (Finnish Environment Institute, 2001)
    Monographs of the Boreal Environment Research 19
    This study presents the development and applications of regional and local scale models for use in integrated assessment of air pollution effects in conjunction with large-scale models. A regional deposition model called DAIQUIRI (Deposition, AIr QUality and Integrated Regional Information) for integrated assessment purposes in Finland was constructed, and regional matrices for nitrogen oxides and ammonia were developed from the results of the regional air quality model of the FMI. DAIQUIRI produced similar estimates of deposition from Finnish sources as the original model, and long-term trends and the average level of deposition estimated with DAIQUIRI were found comparable with the monitored deposition levels and trends. For the mid-nineties situation, the regional nitrogen modeling resulted in 9% to 19% (depending on the region compared) larger estimates of areas with acidity critical load exceedances than when using European scale nitrogen deposition modeling.In this work, also a method for estimating the impacts of local NOx emissions on urban and sub-urban ozone levels was developed and tested. The study concentrated on representing the destruction of ozone by fresh NO emissions in urban areas for future use in integrated assessment modeling of ozone control strategies. Correlation coefficients between measured daytime ozone values in the study area were found to improve from 0.64 (correlation between urban and surrounding rural measurements) to 0.85, on the average. The average correlation between daytime large-scale model estimates and urban site measurements was found to improve from 0.37 to 0.58.In the study, also integrated assessment model applications were carried out at European, national and local levels. The synergies between control strategies for CO2 and acidification and ozone formation in the case of the UN/FCCC Kyoto protocol and the air quality targets of the EU were assessed with the help of coupled models. With two alternative energy scenarios reflecting the Kyoto targets for CO2, reductions of sulfur and NOx emissions between 12% and 22% and 8% to 12%, respectively, were estimated by 2010 in the EU-15 with the present emission control legislation. Due to the lower activity levels generating less emissions and the cleaner energy forms used, 35-43% cost savings in further technical emission controls required for achieving the EU air quality targets would be achieved with the scenarios studied. Case studies for Finland indicated that there has been a decrease of 60% in the area at risk of acidification from 1990 to 1995, and that the declining trend is expected to continue due to the recent international emission reduction agreements within the UN/ECE and the EU. Implementation of the Kyoto protocol in Finland and in the whole of EU-15 (with the present emission legislation) could bring up to 8% more reduction of ecosystems at risk of acidification in Finland by 2010 than the recent UN/ECE protocol.An uncertainty analysis of acidification integrated assessment modeling in Finland indicated that critical loads dominate the uncertainty. Estimates are becoming more robust, as the general level of deposition is decreasing. In Finland, further efforts to reduce the overall uncertainty should be mainly directed to more accurate description of critical thresholds. In areas affected by major nearby emission sources, also uncertainties in emissions and deposition are significant. The models and their applications presented in this study contributed to identifying the problem characteristics and have supported environmental policy development at international, national and regional levels.
  • Mattsson, Tuija (Finnish Environment Institute, 2010)
    Monographs of the Boreal Environment Research 36
    The terrestrial export of dissolved organic matter (DOM) is associated with climate, vegetation and land use, and thus is under the influence of climatic variability and human interference with terrestrial ecosystems, their soils and hydrological cycles. The present study provides an assessment of spatial variation of DOM concentrations and export, and interactions between DOM, catchment characteristics, land use and climatic factors in boreal catchments. The influence of catchment characteristics, land use and climatic drivers on the concentrations and export of total organic carbon (TOC), total organic nitrogen (TON) and dissolved organic phosphorus (DOP) was estimated using stream water quality, forest inventory and climatic data from 42 Finnish pristine forested headwater catchments, and water quality monitoring, GIS land use, forest inventory and climatic data from the 36 main Finnish rivers (and their sub-catchments) flowing to the Baltic Sea. Moreover, the export of DOM in relation to land use along a European climatic gradient was studied using river water quality and land use data from four European areas. Additionally, the role of organic and minerogenic acidity in controlling pH levels in Finnish rivers and pristine streams was studied by measuring organic anion, sulphate (SO4) and base cation (Ca, Mg, K and Na) concentrations. In all study catchments, TOC was a major fraction of DOM, with much lower proportions of TON and DOP. Moreover, most of TOC and TON was in a dissolved form. The correlation between TOC and TON concentrations was strong and TOC concentrations explained 78% of the variation in TON concentrations in pristine headwater streams. In a subgroup of 20 headwater catchments with similar climatic conditions and low N deposition in eastern Finland, the proportion of peatlands in the catchment and the proportion of Norway spruce (Picea abies Karsten) of the tree stand had the strongest correlation with the TOC and TON concentrations and export. In Finnish river basins, TOC export increased with the increasing proportion of peatland in the catchment, whereas TON export increased with increasing extent of agricultural land. The highest DOP concentrations and export were recorded in river basins with a high extent of agricultural land and urban areas, reflecting the influence of human impact on DOP loads. However, the most important predictor for TOC, TON and DOP export in Finnish rivers was the proportion of upstream lakes in the catchment. The higher the upstream lake percentage, the lower the export, indicating organic matter retention in lakes. Molar TOC:TON ratio decreased from headwater catchments covered by forests and peatlands to the large river basins with mixed land use, emphasising the effect of the land use gradient on the stoichiometry of rivers. This study also demonstrated that the land use of the catchments is related to both organic and minerogenic acidity in rivers and pristine headwater streams. Organic anion dominated in rivers and streams situated in northern Finland, reflecting the higher extent of peatlands in these areas, whereas SO4 dominated in southern Finland and on western coastal areas, where the extent of fertile areas, agricultural land, urban areas, acid sulphate soils, and sulphate deposition is highest. High TOC concentrations decreased pH values in the stream and river water, whereas no correlation between SO4 concentrations and pH was observed. This underlines the importance of organic acids in controlling pH levels in Finnish pristine headwater streams and main rivers. High SO4 concentrations were associated with high base cation concentrations and fertile areas, which buffered the effects of SO4 on pH.
  • Kupiainen, Kaarle (Finnish Environment Institute, 2007)
    Monographs of the Boreal Environment Research 26
    Vehicles affect the concentrations of ambient airborne particles through exhaust emissions, but particles are also formed in the mechanical processes in the tire-road interface, brakes, and engine. Particles deposited on or in the vicinity of the road may be re-entrained, or resuspended, into air through vehicle-induced turbulence and shearing stress of the tires. A commonly used term for these particles is ?road dust?. The processes affecting road dust emissions are complex and currently not well known.Road dust has been acknowledged as a dominant source of PM10 especially during spring in the sub-arctic urban areas, e.g. in Scandinavia, Finland, North America and Japan. The high proportion of road dust in sub-arctic regions of the world has been linked to the snowy winter conditions that make it necessary to use traction control methods. Traction control methods include dispersion of traction sand, melting of ice with brine solutions, and equipping the tires with either metal studs (studded winter tires), snow chains, or special tire design (friction tires). Several of these methods enhance the formation of mineral particles from pavement wear and/or from traction sand that accumulate in the road environment during winter. When snow and ice melt and surfaces dry out, traffic-induced turbulence makes some of the particles airborne.A general aim of this study was to study processes and factors underlying and affecting the formation and emissions of road dust from paved road surfaces. Special emphasis was placed on studying particle formation and sources during tire road interaction, especially when different applications of traction control, namely traction sanding and/or winter tires were in use. Respirable particles with aerodynamic diameter below 10 micrometers (PM10) have been the main concern, but other size ranges and particle size distributions were also studied. The following specific research questions were addressed: i) How do traction sanding and physical properties of the traction sand aggregate affect formation of road dust? ii) How do studded tires affect the formation of road dust when compared with friction tires? iii) What are the composition and sources of airborne road dust in a road simulator and during a springtime road dust episode in Finland? iv) What is the size distribution of abrasion particles from tire-road interaction? The studies were conducted both in a road simulator and in field conditions.The test results from the road simulator showed that traction sanding increased road dust emissions, and that the effect became more dominant with increasing sand load. A high percentage of fine-grained anti-skid aggregate of overall grading increased the PM10 concentrations. Anti-skid aggregate with poor resistance to fragmentation resulted in higher PM levels compared with the other aggregates, and the effect became more significant with higher aggregate loads. Glaciofluvial aggregates tended to cause higher particle concentrations than crushed rocks with good fragmentation resistance. Comparison of tire types showed that studded tires result in higher formation of PM emissions compared with friction tires. The same trend between the tires was present in the tests with and without anti-skid aggregate. This finding applies to test conditions of the road simulator with negligible resuspension.Source and composition analysis showed that the particles in the road simulator were mainly minerals and originated from both traction sand and pavement aggregates. A clear contribution of particles from anti-skid aggregate to ambient PM and dust deposition was also observed in urban conditions. The road simulator results showed that the interaction between tires, anti-skid aggregate and road surface is important in dust production and the relative contributions of these sources depend on their properties. Traction sand grains are fragmented into smaller particles under the tires, but they also wear the pavement aggregate. Therefore particles from both aggregates are observed. The mass size distribution of traction sand and pavement wear particles was mainly coarse, but fine and submicron particles were also present.
  • Bergström, Irina (Finnish Environment Institute, 2011)
    Monographs of the Boreal Environment Research 38
    The carbon dioxide (CO2) and methane (CH4) fluxes from aquatic sediments have recently received considerable interest because of the role of these gases in enhancing climate warming. CO2 is the main end product of aerobic respiration and CH4 is produced in large amounts under anaerobic conditions. Shallow, vegetated sediments are an important source of both gases. CH4 may be transported via rhizomes and aerenchymal tissues of aquatic plants from the sediment to the atmosphere, thus avoiding oxidation in the aerated sediment surface and water column. Temperature is known to be a key factor affecting benthic CO2 and CH4 flux rates, but the interplay between other factors that may affect the fluxes from sediments is still poorly known. In order to study the spatial and temporal variability of carbon gas fluxes in boreal aquatic sediments, the area-based CO2 production rates in lake and brackish water sediments and CH4 emissions in vegetated lake littorals were measured in this work. The effects of temperature, sediment quality, plant species, zoobenthos and seasonal variation on flux rates were also estimated. The range of CO2 production rates measured in the field was 0.1–12.0 mg C m–2 h–1 and that of CH4 emission rates 0–14.3 mg C m–2 h–1. When incubated at elevated temperatures (up to 30 °C) in the laboratory, the CO2 production rates increased up to 70 mg C m–2 h–1. Temperature explained 70–94% of the temporal variation in the CO2 production in lake sites and 51% in a brackish water site. In the lake mesocosm, temperature explained 50–90% of the variation of CH4 emission. By contrast, CH4 oxidation rate was not dependent on temperature. The CH4 fluxes through the plants of six emergent and floating-leaved plant species were studied in the field (temperature range 20.4–24.9 °C). Stands of the emergent macrophyte Phragmites australis emitted the largest amounts of CH4 (mean emission 13.9 ± 4.0 (SD) mg C m-2 h–1), the mean emission rate being correlated with mean net primary production (NPP) and mean solar radiation. In the stands of floating-leaved Nuphar lutea the mean CH4 efflux (0.5 ± 0.1 (SD) mg C m–2 h–1) was negatively correlated with mean fetch and positively with percentage cover of leaves on the water surface. On a regional level, stands of the emergents P. australis and Equisetum fluviatile emitted 32% more CH4 than natural open peatland during the growing season, although their areal coverage in the study region was only 41% of that of peatland area. Climate warming will presumably increase the carbon gas emission from vegetated littorals. The model-based estimated increase of CO2 production rate in June was 29% and for CH4 emissions as much as 65% for the time interval of 110 years from 1961–1990 to 2071–2100. The results indicate that carbon gas fluxes from aquatic sediments, especially from vegetated littorals, are significant at the landscape level. They are linked to temperature but also to several other interacting factors such as e.g. water and bottom quality and ecosystem composition. Detailed investigation of the overall links between the causes and effects is urgently needed in order to understand and predict the changes caused by warming climate.

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