Effects of chronic elevated ozone exposure on gas exchange responses of adult beech trees (Fagus sylvatica) as related to the within-canopy light gradient

The effects of elevated O₃ on photosynthetic properties in adult beech trees (Fagus sylvatica) were investigated in relation to leaf mass per area as a measure of the gradually changing, within-canopy light availability. Leaves under elevated O₃ showed decreased stomatal conductance at unchanged carboxylation capacity of Rubisco, which was consistent with enhanced δ¹³C of leaf organic matter, regardless of the light environment during growth. In parallel, increased energy demand for O₃ detoxification and repair was suggested under elevated O₃ owing to enhanced dark respiration. Only in shade-grown leaves, light-limited photosynthesis was reduced under elevated O₃, this effect being accompanied by lowered F_v/F_m. These results suggest that chronic O₃ exposure primarily caused stomatal closure to adult beech trees in the field regardless of the within-canopy light gradient. However, light limitation apparently raised the O₃ sensitivity of photosynthesis and accelerated senescence in shade leaves.     

Effective pollutant emission heights for atmospheric transport modelling based on real-world information

Emission data needed as input for the operation of atmospheric models should not only be spatially and temporally resolved. Another important feature is the effective emission height which significantly influences modelled concentration values. Unfortunately this information, which is especially relevant for large point sources, is usually not available and simple assumptions are often used in atmospheric models. As a contribution to improve knowledge on emission heights this paper provides typical default values for the driving parameters stack height and flue gas temperature, velocity and flow rate for different industrial sources. The results were derived from an analysis of the probably most comprehensive database of real-world stack information existing in Europe based on German industrial data. A bottom-up calculation of effective emission heights applying equations used for Gaussian dispersion models shows significant differences depending on source and air pollutant and compared to approaches currently used for atmospheric transport modelling.     

Metals pollution and human bioaccessibility of topsoils in Grugliasco (Italy)

Polluted soils can present a significant health risk especially in an urban environment. Most current legislation and health risk frameworks are based on pseudototal metal content. However, only a fraction of these concentrations is available for plant and human uptake. The aim of this work was to study the diffuse metal contamination in the soils of a municipality in Northern Italy in terms of: (i) metal availability, and (ii) metal accessibility to the human body and its relationship to soil properties, considering lead, copper, zinc, nickel, and chromium. Soil metal content was measured simulating availability conditions. Human bioaccessibility was derived from a modified physiologically-based extraction test. The human bioaccessible content was then estimated taking into account the relationships between pseudototal content and selected soil parameters. For the case study, the prediction of human bioaccessibility based on pseudototal content, organic matter and soil texture produced statistically significant models, with r² = 0.60 for Cu, r² = 0.53 for Pb and r² = 0.42 for Zn.     

Intra- and inter-annual variability of VOC emissions from natural and semi-natural vegetation in Europe and neighbouring countries

Biogenic VOC emission estimates from the earth's surface are crucial input parameters in air quality models. Knowledge accumulated in the last years about BVOC source distributions and chemical compound species emission profiles in Europe as well as the demand of air quality modellers for a finer resolution in space and time of BVOC estimates have led to the set-up of new emission modelling systems. An updated fast BVOC emission modelling platform explicitly considering the seasonality of emission potentials and leaf temperature gradients in forest canopies by the semi-empirical emission module (seBVOC) will be proposed and used for estimating hourly values of chemical compound-specific emissions in Europe (33–68° north; 10° west to 40° east) in the years 1997, 2000, 2001, and 2003. Spatial resolution will be 10 km by 10 km. The database used contains latest land and forest distributions, updated foliar biomass densities, leaf area indices (LAI), and plant as well as chemical compound-specific emission potentials, if available. Meteorological input parameters for the respective years will be generated using the non-hydrostatic meteorological model MM5. Highest BVOC emissions occur in daytime hours around noon from the end of May to mid-August in the Mediterranean area and from the mid of June to the end of July in the boreal forests. Comparison of 3 BVOC model approaches will reveal that for July 2003, the European isoprene and monoterpene totals range from 1124 Gg to 1446 Gg and from 338 Gg to 1112 Gg, respectively. Small-scale deviations may be as high as ±0.6 Mg km^?2 for July 2003, reflecting the current uncertainty range for BVOC estimates. Key sources of errors in inventories are still insufficiently detailed land use data for some areas and lacking chemically speciated plant-specific emission potentials in particular in boreal, south-eastern, and northern African landscapes. The hourly emissions of isoprene, speciated terpenes, and oxyVOC have been made available by the NatAir database.     

Absorptive Capacities for Sustainability Technologies： Perspectives from the BRICS and China

For the development process in the rapidly growing economies, knowledge transfer and technology cooperation are becoming important issues. Research and technological competences are key indicators for the absorptive capacity of sustainability technologies and for the ability to export them. These issues are analyzed empirically for Brazil, Russia, India, China and South Africa （BRICS）. Sustainability related research in BRICS is mostly carried out within broader, more sector oriented programmes. Specialization patterns of international patents and in foreign trade indicate various strengths and weaknesses of the BRICS countries. The differences within the countries imply that the analysis must proceed at a technology specific level. China has considerable capabilities in technologies such as photovoltaics, solar thermal or buildings. There is a strong need for strategic positioning of the countries and for coordination of the various policy fields involved.     

Impact of common cytostatic drugs on pollen fertility in higher plants

Cytostatic drugs are among the most toxic chemicals which are produced. Many of them cause damage of the genetic material which may affect the fertility of higher organisms. To study the impact of the widely used anticancer drugs [cisplatin (CisPt), etoposide (Et), and 5-fluorouracil (5-FU)] on the reproduction of higher plants, pollen abortion experiments were conducted with species which belong to major plant families, namely with Tradescantia paludosa (Commelinaceae), Arabidopsis thaliana (Brassicaceae), Chelidonium majus (Papaveraceae), and Alisma plantago-aquatica (Alismataceae). All compounds increased the frequencies of abortive grains. The lowest effective doses were in general in a narrow range (i.e., 1 and 10 mg/kg of dry soil). The effects of the individual drugs were similar in T. paludosa, A. plantago-aquatica, and Ch. majus, while A. thaliana was consistently less sensitive. The highest abortion rate was obtained in most experiments with CisPt, followed by 5-FU and Et. Comparisons of the doses which caused effects in the present experiments in the different species with the predicted environment concentrations and with the levels of the cytostatics which were detected in hospital wastewaters show that the realistic environmental concentrations of the drugs are 4–6 orders of magnitude lower. Therefore, it is unlikely that these drugs affect the fertility of higher plants in aquatic and terrestrial ecosystems.     

Use of passive sampling devices for monitoring and compliance checking of POP concentrations in water

Background

The state of the art of passive water sampling of (nonpolar) organic contaminants is presented. Its suitability for regulatory monitoring is discussed, with an emphasis on the information yielded by passive sampling devices (PSDs), their relevance and associated uncertainties. Almost all persistent organic pollutants (POPs) targeted by the Stockholm Convention are nonpolar or weakly polar, hydrophobic substances, making them ideal targets for sampling in water using PSDs. Widely used nonpolar PSDs include semi-permeable membrane devices, low-density polyethylene and silicone rubber.

Results and discussion

The inter-laboratory variation of equilibrium partition constants between PSD and water is mostly 0.2?C0.5 log units, depending on the exact matrix used. The sampling rate of PSDs is best determined by using performance reference compounds during field deployment. The major advantage of PSDs over alternative matrices applicable in trend monitoring (e.g. sediments or biota) is that the various sources of variance including analytical variance and natural environmental variance can be much better controlled, which in turn results in a reduction of the number of analysed samples required to obtain results with comparable statistical power.

Conclusion

Compliance checking with regulatory limits and analysis of temporal and spatial contaminant trends are two possible fields of application. In contrast to the established use of nonpolar PSDs, polar samplers are insufficiently understood, but research is in progress to develop PSDs for the quantitative assessment of polar waterborne contaminants. In summary, PSD-based monitoring is a mature technique for the measurement of aqueous concentrations of apolar POPs, with a well-defined accuracy and precision.     

Metabolism of gamma‐hexachlorocyclohexah (HCH) in vivo. Metabolism of orally administered gamma‐2,3,4,5,6‐pentachlorocyclohexen (PCCH)

Abstract

Mexacarbate (4‐dimethylamino‐3,5‐xylyl N‐methylcarbamate) insecticide has potential for use in spruce budworm (Choristoneura fumiferana Clem.) control operations in Canada. Its persistence and fate in balsam fir (Abies balsamea (L.) Mill.), litter and soil samples were studied by spraying aerially oil‐based and water‐based formulations, each at 70 g A.I./ha over a coniferous forest near Bathurst, New Brunswick. The oil‐based formulation gave the maximum concentration of the chemical in the substrates studied. In fir needles, the highest concentrations observed were 0.51 ppm and 0.19 ppm (fresh weight) for the oil‐based and emulsion formulations respectively, 1 h after application. The residue levels decreased very rapidly with a half‐life of approximately 5 h. Three and eight days after the spray application of the emulsion and oil formulations respectively, the concentrations of mexacarbate in foliage decreased to trace levels ( 0.008 ppm). Only very low levels of residue were detected in litter and soil. The peak concentrations for the two formulations ranged from 0.02 to 0.11 ppm (fresh weight) in litter and from 0.01 to 0.06 ppm (fresh weight) in soil. The residue levels in both litter and soil decreased to below the detection limit (0.005 ppm) within 1 d. The ground deposit levels found on glass plates and the droplet density and size spectra measured on Kromekote® cards reflected the variations in concentrations found in fir needles, litter and soil samples and correlated with the observed maximum concentrations in them. Under the stipulated use pattern, mexacarbate concentrations found in the terrestrial components studied were low and are not likely to have any undue adverse effects on non‐target species.