Road dust emissions from paved roads measured using different mobile systems

Very few real-world measurements of road dust suspension have been performed to date. This study compares two different techniques (referred to as Sniffer and Emma) to measure road dust emissions. The main differences between the systems are the construction of the inlet, different instruments for recording particulate matter (PM) levels, and different loads on the wheel axes (the weight of Sniffer was much higher than that of Emma). Both systems showed substantial small-scale variations of emission levels along the road, likely depending on-road surface conditions. The variations observed correlated quite well, and the discrepancies are likely a result of variations in dust load on the road surface perpendicular to the driving direction that cause variations in the measurements depending on slightly different paths driven by the two vehicles. Both systems showed a substantial influence on the emission levels depending on the type of tire used. The summer tire showed much lower suspension than the winter tires (one nonstudded and one studded). However, the relative importance of the nonstudded versus studded tire was rather different. For the ratio of studded/nonstudded, Emma shows higher values on all road sections compared with Sniffer. Both techniques showed increased emission levels with increasing vehicle speed. When the speed increased from 50 to 80 km hr(-1), the relative concentrations increased by 30-170% depending on the tire type and dust load. However, for road sections that were very dirty, Sniffer showed a much higher relative increase in the emission level with the nonstudded tire. Sniffer's absolute concentrations were mostly higher than Emma's. Possible reasons for the differences are discussed in the paper. Both systems can be used for studying relative road dust emissions and for designing air quality management strategies.     

A case study of waste management at the Northern Finnish pulp and paper mill complex of Stora Enso Veitsiluoto Mills

This work presents the current waste management system at the pulp and paper mill complex of Stora Enso Oyj Veitsiluoto Mills at Kemi, Northern Finland. This paper covers examples of case studies carried out at the mill and describes how the wastes and by-products are utilized as a neutralizing agent for acidic wastewaters (i.e., green liquor dregs from the causticizing process), as a hardener in filling mine cavities (i.e., ash from the fluidized bed boiler), as a landscaping agent (i.e., ash as well as the fibre clay from chemical wastewater treatment plant), as a hydraulic barrier material for landfills (i.e., fibre clay), and as a soil enrichment agent (i.e., calcium carbonate from the precipitated calcium carbonate plant). In addition, the wood waste from the wood-handling plant, sawmill, packaging pallet plant and from the groundwood mill, as well as the biosludge from the biological wastewater treatment plant, are all incinerated in the fluidized bed boiler for energy production. Due to effective utilization of the solid wastes generated at the mills, the annual amount of waste to be disposed of in the landfill has decreased between 1994 and 2004 from 42,990 to 6083 tonn (expressed as wet weight). The paper also gives an overview of the relevant European Union legislation on the forest industry and on waste management, as well as of the pulping process and of the generation of major solid wastes in the pulp and paper mills.     

Environmental risk assessment of heavy metal extractability in a biosludge from the biological wastewater treatment plant of a pulp and paper mill

A five-stage sequential extraction procedure was used to fractionate heavy metals (Cd, Cu, Pb, Cr, Zn, Fe, Mn, Ni, Co, As, V and Ba) in a biosludge from the biological wastewater treatment plant of Stora Enso Oyj Veitsiluoto Mills at Kemi, Northern Finland, into the following fractions: (1) water-soluble fraction, (2) exchangeable fraction, (3) easily reduced fraction, (4) oxidizable fraction, and (5) residual fraction. The biosludge investigated in this study is a combination of sludge from the primary and secondary clarifiers at the biological wastewater treatment plant. Extraction stages (2)–(4) follow the protocol proposed by the Measurements and Testing Program (formerly BCR Programme) of the European Commission, which is based on acetic acid extraction (stage 2), hydroxylamine hydrochloride extraction (stage 3), and hydrogen peroxide digestion following the ammonium acetate extraction (stage 4). The residual fraction (stage 5) was based on digestion of the residue from stage 4 in a mixture of HF + HNO₃ + HCl. Although metals were extractable in all fractions, the highest concentrations of most of the metals occurred in the residual fraction. From the environmental point of view, it was notable that the total heavy metal concentrations in the biosludge did not exceed the maximal allowable heavy metal concentrations for sewage sludge used in agriculture, set on the basis of environmental protection of soil by European Union Directive 86/278/EEC, and by the Finnish legislation. The Ca (98.6 g kg⁻¹; dry weight) and Mg (2.2 g kg⁻¹; dry weight) concentrations in the biosludge were 62 and 11 times higher than the typical values of 1.6 and of 0.2 g kg⁻¹ (dry weight), respectively, in arable land in Central Finland. The biosludge had a slightly alkaline pH (∼8.30), a high loss-on-ignition value (∼78%) and a liming effect of 10.3% expressed as Ca equivalents (dry weight). This indicates its potential as a soil conditioner and improvement agent, as well as a pH buffer.     

Root fungal colonisation in Deschampsia flexuosa: effects of pollution and neighbouring trees

In industrial barrens adjacent to a nickel-copper smelter at Monchegorsk, the Kola Peninsula, root colonisation in Deschampsia flexuosa by arbuscular mycorrhizal (AM)-type of hyphae was lower than in unpolluted forests (60.9 vs. 80.4%), while Olpidium-colonisation showed a marginally significant decline, and dark septate endophytic (DSE) hyphal colonisation was not affected. We detected an interactive effect of pollution and a neighbouring tree on DSE hyphal colonisation: at the highly polluted sites, colonisation was lower in D. flexuosa growing near trees, whereas at sites with low pollution the presence of the neighbouring tree had no effect on colonisation. High numbers of intracellular DSE sclerotia in the industrial barrens (13.3 vs. 3.4%) may indicate a survial strategy in an unfavourable environment and a dispersal strategy into a more favourable environment. While lower root colonisation by AM fungi has been also earlier reported in graminoids for heavy metal contamination, the results on other ubiquitous fungi colonising D. flexuosa roots are more novel.     

Long-term changes in acidity and DOC in throughfall and soil water in Finnish forests

The main objective of this study was to examine if any detectable trends in dissolved organic carbon (DOC), sulphate (SO₄-S) concentrations and acid neutralizing capacity (ANC) in throughfall (TF) and soil water (SW) could be found during 1990–2010 and to relate them to recent changes in decreased acid deposition. The study was conducted in seven boreal coniferous forest sites: four of which are managed and three unmanaged forests sites. Generally, temporal trend showed a significant decrease in SO₄-S concentrations in bulk precipitation (BP), TF and SW. At some of the sites, there was an increasing tendency in BP and TF in the DOC concentrations. This feature coincides with decreasing SO₄-S concentration, indicating that SO₄-S may be an important driver of DOC release from the canopy. However, a slightly increased temperature, larger senescing needle mass and consequently increased decaying activity in the canopy may partly explain the increasing trend in DOC. In SW, no consistent DOC trend was seen. At some sites, the decreased base cation concentrations mostly account for the decrease in the ANC values in SW and TF.     

The Importance of Leaching from Litter Collected in Litterfall Traps

Litterfall (LF) is usually collected by means of opentraps. However, this litter will be subject toleaching by the throughfall which passes through theaccumulated litter in the traps. The nutrients lostduring this leaching are not taken into account in thecalculation of LF nutrient fluxes. We report theresults from a 2-month (August–September) studycarried out in 8 northern coniferous forest stands toassess the possible importance of leaching from litterin LF traps. Compared to throughfall (TF), thelitterfall leachate (LFL_gross), which includes athroughfall component, had significantly (p < 0.05)higher concentrations and fluxes of Ca, Mg, Na and S.The average net LFL (i.e., LFL_net = LFL_gross-TF) fluxes were 21 (Ca), 7 (Mg), 57 (K), 10 (Na), 10 (N), and 19 (S) mg m^-2 mo^-1. LFL_net accounted for 42%, 37% and 50% of the LFL_gross flux, and for 91%, 51% and 49% of the total litterfall flux (i.e.,LF + LFL_net) of Na, S and K, respectively. ForCa, Mg and N, the LFL_net flux accounted for 64%,58% and 29% of the LFL_gross flux, and for< 14% of the total litterfall flux. Compared to TF,LF was the dominant return pathway for Ca, Mg and N tothe forest floor regardless of whether LFL_net wasincluded or not. However, for K and S, takingLFL_net into account determined whether TF or LFwas the dominant pathway. TF remained the dominantpathway for Na even when LFL_net was included.     

Levels and Characteristics of TOC in Throughfall, Forest Floor Leachate and Soil Solution in Undisturbed Boreal Forest Ecosystems

Total organic carbon (TOC) concentrations and fluxes in throughfall, forest floor leachate, soil solution (15 and 35 cm depths), and groundwater for coniferous forest sites in the boreal zone throughout Finland are described. Eight upland forest stands and one peatland forest stand are included in the study and the samples were collected during 1991–1997. Carbon (C) pools in the living tree biomass and soil compartments are presented, and the hydrophobic/hydrophilic and acidic components of dissolved organic carbon (DOC) in samples collected in autumn 1999 and spring 2000 from two of the sites are compared. Biomass (aboveground and belowground) pools of C averaged 88 Mg ha^-1 and soil (humus layer + 20 cm soil layer) averaged 55 Mg ha^-1. Stand throughfall TOC monthly mean concentrations ranged from 4.0 to 18.6 mg L^-1 and annual fluxes averaged 4.0 g m^-2 yr^-1. TOC concentrations in the water passing through the forest floor and soil decreased with depth. Plot mean concentrations at 35 cm depth values ranged from 4.1 to 21.2 mg L^-1 and fluxes averaged 3.7 g m^-2 yr^-1. Throughfall TOC concentrations were lowest during the winter, snowfall period and highest during the growing season. No monotonic trends in throughfall TOC concentrations over the 1991–1997 period were found. Soil solution TOC concentrations varied considerably, both within and between years. DOC in throughfall, forest floor, and soil solutions and in both autumn and spring seasons was dominated by hydrophobic fractions, particularly acids. Spruce canopies and litter appear to be important sources of soluble organic carbon, particularly acidic and hydrophobic compounds. Further studies on the nature and dynamics of organic carbon fluxing through coniferous, boreal forest ecosystems are needed.     

Mother really knows best: host choice of adult phytophagous insect females reflects a within-host variation in suitability as larval food

Non-random distribution patterns of specialized phytophagous insects on their hosts may depend on intraspecific differences in plant tissue quality, including nutrients and secondary compounds. Secondary compounds are involved in plant resistance, but are also important for the recognition and acceptability of plants as resources by specialized insects. If individuals within a plant species vary in their content of such secondary substances, there may also be qualitative differences between them. In such cases, natural selection will favor insects with the ability to distinguish and prefer the more suitable plants. In Sweden, the leaf beetle Gonioctena linnaeana Schrank (Coleoptera, Chrysomelidae) is highly specialized on one host, the native willow Salix triandra L (Salicaceae). Field observations reveal that some host plants in a population harbor many feeding larvae, causing severe defoliation, whereas neighboring plants may have few or no feeding larvae. Our hypothesis is that the distribution pattern of G. linnaeana larvae in this population results from qualitative differences between individual host plants in combination with the ability of G. linnaeana females to distinguish between plants that are suitable and not suitable for offspring performance. We examine whether larval survival differs depending on diet and whether the content of secondary chemical compounds explains female preference. Based on the higher survival rate of larvae reared on leaves from preferred hosts, we conclude that G. linnaeana females have evolved a behavior that maximizes offspring performance and thus positively affects female fitness. A chemical survey of the plants indicates that luteolin-7-glucoside and an unidentified flavonoid are important for separating the preferred from the non-preferred plants.     

Herbivores and variation in the composition of specific phenolics of boreal coniferous trees: a search for patterns

Coniferous trees of different species, or of the same species growing at different locations, vary in the extent to which they are attacked by various herbivores and pathogens. Plant secondary metabolites might be a key to understanding some of this variation. At the site level, we investigated if there was an intra- or interspecies pattern for individual compounds (or for groups of compounds) and their relationship to indices of plant nitrogen and plant productivity. For example, do plants exhibit similar covariance in defence compounds when evaluated across a number of sites varying in productivity? Here, we concentrated on the phenolic profile of Pinus sylvestris, Picea abies, Juniperus communis and Pinus contorta. Our results indicate striking differences in secondary chemistry profiles of the twigs including needles of the trees and in the inter-relationships amongst individual compounds and groups of compounds. Flavonols occurred in high variety in P. sylvestris and were highly correlated with each other, differing from P. contorta. But the results of the factor analyses indicate an underlying pattern for flavonols of the coumaroyl type for P. contorta. In contrast, the compounds of the other tree species showed a low degree of inter-correlation. Co-occurring phenolics of different tree species were not correlated. Overall, our analysis of site indices indicated that plant productivity was not a useful predictor for the concentration of specific phenolics. The relationship amongst plant nitrogen and specific phenolics might be the result of two defence strategies (one related and the other not related to nitrogen content). This might enable the plant to shift its defences against attacks with a high degree of flexibility.     

Associations of plant fitness, leaf chemistry, and damage suggest selection mosaic in plant-herbivore interactions

The geographic mosaic theory of coevolution states that variation in species interactions forms the raw material for coevolutionary processes, which take place over large geographic scales. One key assumption underlying the process of coevolution in plant-herbivore interactions is that herbivores exert selection on their host plants and that this selection varies among plant populations. We examined spatial variation in the existence and strength of phenotypic selection on host plant resistance exerted by specialist herbivores in 17 archipelago populations of the perennial herb Vincetoxicum hirundinaria (Asclepiadaceae). In these highly fragmented populations, V. hirundinaria is consumed by the larvae of two specialist herbivores: the folivorous moth Abrostola asclepiadis and the seed predator Euphranta connexa. Selection imposed on host plants by these herbivores was examined by analyzing the associations between levels of herbivory, plant fitness, and contents of a number of leaf chemicals reflecting plant resistance to and quality for the herbivores. We found extensive spatial variation in the levels of herbivory and in plant fitness. More importantly, the impact of both leaf herbivory and seed predation on plant fitness varied among plant populations, indicating spatial variation in phenotypic selection. In addition, leaf chemistry varied widely among plant populations, reflecting spatial variation in plant quality as food for the herbivores. However, leaf compounds influenced folivory similarly in all the studied plant populations, and interestingly, some of the compounds were associated with the intensity of seed predation. Finally, some of the leaf compounds were associated with plant fitness, and the strength and direction of these associations varied among plant populations. The observed spatial variation in the strength of the interactions between V. hirundinaria and its specialist herbivores suggests a geographic selection mosaic. Because the occurrence and strength of spatial variation varied between the two specialist herbivores, our results highlight the importance of considering multiple enemies when trying to understand evolution of interactions between plants and their herbivores.