Quantitative analysis of environmental factors in differential weighing of blank Teflon filters

Mass differences less than 100 microg must be correctly measured in gravimetric analysis of particles collected on filters. Even small variations in mass measurement may contribute significant errors to calculated concentrations. In addition to the collected particles, a number of other factors affect the observed mass difference between the measurements before and after sampling. The most often controlled of these factors are static charge, temperature, and humidity. Using 951 laboratory blank filter weights, we have statistically analyzed these and other factors that affect the observed filter weight. Some of these are controllable or correctable; others are not and enter into the final results as errors. The standard deviation of differential blank filter weighing after applying all corrections was 2.7 microg. The most important correctable factors are air buoyancy variation and filter storage time. When weighing blank Teflon filters at relative humidity < 50%, these are an order of magnitude more important than weighing-room humidity. Using field blank filters in each weighing batch could control these three factors but also doubles the errors caused by balance random variation and filter handling contamination, because four weighing measurements and the handling of two filters are needed to obtain one corrected differential mass result.     

Cleptoparasitism increases the host finding ability of a polyphagous parasitoid species,<Emphasis Type="Italic"> Rhopalicus tutela</Emphasis> (Hymenoptera: Pteromalidae)

Host finding abilities were investigated in the braconid Coeloides bostrichorum and the pteromalid Rhopalicus tutela, two ectoparasitoid wasps attacking the late instar of the bark beetle Ips typographus. Under laboratory conditions, important differences in the host-searching behaviour of these species were found, R. tutela being highly mobile as compared to C. bostrichorum. In the presence of C. bostrichorum, R. tutela behaved as a cleptoparasitoid, displacing the females from their oviposition sites and stealing the hosts previously located by the braconid. This behaviour facilitated host finding in R. tutela and could partly explain the relative success of the polyphagous R. tutela when occurring with the more specialised C. bostrichorum.Communicated by R.F.A. Moritz     

Multivariate Statistics of the Pyrolysis Products of High Molecular Components in Pulping Wastewaters to Explain Their Toxicity (6 pp)

Background, Aim and Scope At present, large-scale paper manufacture involves delignification and bleaching by elemental chlorine free (ECF) or totally chlorine free (TCF) processes. The wastewater is purified by secondary treatment (mechanical, chemical and biological) which removes most of the toxic substances from the discharge. However, we found residual toxicity in the high molecular (> 1000 D) matter (HMWM) of the discharge by test of the RET (reverse electronic transfer) inhibition. This fraction consists mainly of polydisperse lignin (LIG) and carbohydrate (CH) macromolecules. Structural units in these molecules are studied by pyrolysis gas chromatography / mass spectrometry (Pyr-GC/MS). In the present work, our aim was to find out those structural units which could explain the RET toxicity of LIG or CH molecules. We compared statistically RET toxicity values of the HMWM samples from treated wastewaters of pilot pulping experiments and intensity variation of the pyrolysis product gas chromatograms of these samples. This application is a novel study procedure. Methods Pyrolysis products (Py-GC/MS results) and inhibition of RET (reverse electronic transport toxicity) as TU50 and TU20 of HMWM (High Molecular Weight Material; Mw > 1000 D) were compared by multivariate statistics. The samples were from laboratory pilot stages of TCF (Totally Chlorine Free) and ECF (Elemental Chlorine Free) manufacture of softwood pulp. Py-GC/MS was done without and with addition of TMAH (Tetra Methyl Ammonium Hydroxide). The name and structure of each abundant fragment compound was identified from its retention time and mass spectrum compared to authentic reference compounds or literature. Four sets of Toxicity Units (TUs) and GC peak areas of the pyrolysis fragments were obtained. The data were normalized by division with LIG (lignin content of each sample). TU values were dependent and the fragment values independent (explanatory) variables in statistical treatments by SPSS system. Separate analyses of correlations, principal components (PCA) and stepwise multiple linear regression (SMLR) were performed from the four sample sets TCF and ECF with and without TMAH. Results and Discussion From the CH fragments, 2-furfural in TCF, and from the LIG fragments, styrene in ECF showed the highest probabilities to originate from source structures of toxicity. Other possible compounds in concern were indicated to be CH fragment 2-methyl-2-cyclopenten-1-one in ECF and LIG fragments 2-methoxy-4-methylphenol, 4,5-dimethoxy-2-methylphenol and 2-methylphenol in TCF.     

PLATIN (plant-atmosphere interaction) II: Co-occurrence of high ambient ozone concentrations and factors limiting plant absorbed dose

There is an ongoing debate as to which components of the ambient ozone (O3) exposure dynamics best explain adverse crop yield responses. A key issue is regarding the importance of peak versus mid-range hourly ambient O3 concentrations. While in this paper the importance of peak atmospheric O3 concentrations is not discounted, if they occur at a time when plants are conducive for uptake, the corresponding importance of more frequently occurring mid-range O3 concentrations is described. The probability of co-occurrence of high O3 concentrations and O3 uptake limiting factors is provided using coherent data sets of O3 concentration, air temperature, air humidity, mean horizontal wind velocity and global radiation measured at representative US and German air quality monitoring sites. Using the PLant-ATmosphere INteraction (PLATIN) model, the significance of the aforementioned meteorological parameters on ozone uptake is examined. In addition, the limitations of describing the O3 exposure for plants under ambient, chamberless conditions by SUM06, AOT40 or W126 exposure indices are discussed.     

Aerosol particle number concentration measurements in five European cities using TSI-3022 condensation particle counter over a three-year period during health effects of air pollution on susceptible subpopulations

In this study, long-term aerosol particle total number concentration measurements in five metropolitan areas across Europe are presented. The measurements have been carried out in Augsburg, Barcelona, Helsinki, Rome, and Stockholm using the same instrument, a condensation particle counter (TSI model 3022). The results show that in all of the studied cities, the winter concentrations are higher than the summer concentrations. In Helsinki and in Stockholm, winter concentrations are higher by a factor of two and in Augsburg almost by a factor of three compared with summer months. The winter maximum of the monthly average concentrations in these cities is between 10,000 cm(-3) and 20,000 cm(-3), whereas the summer min is approximately 5000-6000 cm(-3). In Rome and in Barcelona, the winters are more polluted compared with summers by as much as a factor of 4-10. The winter maximum in both Rome and Barcelona is close to 100,000 cm(-3), whereas the summer minimum is > 10,000 cm(-3). During the weekdays the maximum of the hourly average concentrations in all of the cities is detected during the morning hours between 7 and 10 a.m. The evening maxima were present in Barcelona, Rome, and Augsburg, but these were not as pronounced as the morning ones. The daily maxima in Helsinki and Stockholm are close or even lower than the daily minima in the more polluted cities. The concentrations between these two groups of cities are different with a factor of about five during the whole day. The study pointed out the influence of the selection of the measurement site and the configuration of the sampling line on the observed concentrations.     

Gas-phase degradation of CCl<Subscript>4</Subscript>, CHCl<Subscript>3</Subscript> and CH<Subscript>2</Subscript>Cl<Subscript>2</Subscript> over metallic Fe

We studied the hydrolysis of gas-phase carbon tetrachloride (CCl₄), chloroform (CHCl₃), and dichloromethane (CH₂Cl₂) over a metallic Fe surface for its application in combination with air stripping and soil vapour extraction. The effects of chlorocarbon concentration, type and preparation of the iron-containing material, humidity, and temperature on process performance are reported. The hydrolysis of chlorinated methane derivatives is catalysed by metallic iron resulting in a noticeable decrease of the reaction temperature. The reaction kinetics were found to be consistent with the Langmuir-Hinshelwood model.     

Diversifying forest expertise: forest journals narrating policy change

ABSTRACT

During policy change, the role of the actors communicating the change to different audiences is accentuated. The media plays an increasing role, either as an actor or by providing a stage for other actors. In particular, specialised journals represent an influential, albeit understudied, sphere of policy studies. We use the narrative policy framework complemented with frame analysis to trace how specialised media can affect policy implementation through implicit suggestions for action. Using this combined approach, we analyse how specialised forest journals, which are the most important forest information source for Finnish forest owners, have conveyed the renewal of forest legislation in Finland. The core message of the journals is that forest owners should, despite their new freedom granted by the reform, rely on experts rather than experimenting when managing their forests. This suggests that the media contributes to a path-dependent continuation of a forest policy that is based on a rationalistic exploitation ethos. The innovative potential, which the policy change aimed at encouraging, is thereby partially undermined. However, the analysis of the narratives also reveals that forest expertise and professionalism are diversifying. This notion is important as diversity can eventually lead to narratives supporting more fundamental change in forests management.     

Deposition Monitoring in Europe

A monitoring station for atmospheric deposition was designed and constructed. Three such stations were applied in a pilot project for a year on three sites (Speulder forest in The Netherlands, Auchencorth in Scotland and Melpitz in Germany) in different regions in Europe to estimate local inputs and to validate deposition models which are currently used or developed to estimate ecosystem specific deposition in Europe. Fluxes at Auchencorth Moss are lowest for all components, except for those much influenced by the sea as a source. As Melpitz is located far away from seas, these components are lowest at this site. Wet deposition is the dominant source of input at Auchencorth, whereas at Speulder forest, through its roughness and pollution climate, dry deposition is dominant. At this site dry deposition velocities are highest. Melpitz is a polluted site. Particularly sulphur deposition is high. It is recommended to equip several locations in Europe with intensive deposition monitoring methods. Such a network will be an extension of existing monitoring programmes on air pollution, such as that run by Eurepean Monitoring and Evaluation Programme for the long-range transmission of air pollutants in Europe (EMEP). The intensive monitoring locations should be selected based on pollution climates and type of vegetation, common in Europe.     

Geographic variation in maternal investment: acidity affects egg size and fecundity in Rana arvalis

Environmental-stress-mediated geographic variation in reproductive parameters has been little studied in natural vertebrate populations outside the context of climatic variation. Based on life-history theory, an increase in the degree of environmental stress experienced by a population should lead to (1) a shift in reproductive allocation from fecundity to offspring quality, (2) stronger trade-offs between reproductive parameters, and (3) changes in the relationship between female phenotype and maternal investment. To test these predictions, we investigated geographic variation in maternal investment of moor frogs (Rana arvalis) in relation to breeding site acidity (pH 4-8). We found that mean egg size increased and clutch size and total reproductive output (TRO) decreased with increasing acidity among 19 Swedish moor frog populations. Tests for variation and co-variation in maternal investment and female size and age in 233 females from a subset of four acid origin (AO) and four neutral origin (NO) populations revealed that clutch size and TRO increased with female size in both acid and neutral environments. However, in AO populations, egg size also increased with female size, and clutch size and TRO with female age, whereas in NO populations, egg size increased with female age. The strength of the egg-size-clutch-size tradeoff tended to be stronger in AO than in NO females as expected if the former experience stronger environmental constraints. All in all, these results suggest that environmental acidification selects for investment in larger eggs at a cost to fecundity, imposes negative effects on reproductive output, and alters the relationship between female phenotype and maternal investment.