Levels of dioxins and furans in urban surface soil in Trondheim, Norway

A study was conducted on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in surface soil in order to determine the concentration levels and possibly distinguishing between known and potential sources. The concentration levels are low (0.16-14 ng I-TEQ kg(-1)). The results show a clear pattern where the highest concentration levels were found in the oldest parts of the city. A number of sources were recognised in the soil samples through congener profiles, not all of them active, although similar congener profiles make it extremely difficult to distinguish between different sources. Estimations show that the municipal solid waste incinerator (MSWI) and domestic wood burning are the largest PCDD/F pollution sources within the area.     

AhR agonist and genotoxicant bioavailability in a PAH-contaminated soil undergoing biological treatment

Background, aim, and scope  Degradation of the 16 US EPA priority PAHs in soil subjected to bioremediation is often achieved. However, the PAH loss is not always followed by a reduction in soil toxicity. For instance, bioanalytical testing of such soil using the chemical-activated luciferase gene expression (CALUX) assay, measuring the combined effect of all Ah receptor (AhR) activating compounds, occasionally indicates that the loss of PAHs does not correlate with the loss of Ah receptor-active compounds in the soil. In addition, standard PAH analysis does not address the issue of total toxicant bioavailability in bioremediated soil. Materials and methods  To address these questions, we have used the CALUX AhR agonist bioassay and the Comet genotoxicity bioassay with RTL-W1 cells to evaluate the toxic potential of different extracts from a PAH-contaminated soil undergoing large-scale bioremediation. The extracts were also chemically analyzed for PAH16 and PCDD/PCDF. Soil sampled on five occasions between day 0 and day 274 of biological treatment was shaken with n-butanol with vortex mixing at room temperature to determine the bioavailable fraction of contaminants. To establish total concentrations, parts of the same samples were extracted using an accelerated solvent extractor (ASE) with toluene at 100°C. The extracts were tested as inducers of AhR-dependent luciferase activity in the CALUX assay and for DNA breakage potential in the Comet bioassay. Results  The chemical analysis of the toluene extracts indicated slow degradation rates and the CALUX assay indicated high levels of AhR agonists in the same extracts. Compared to day 0, the bioavailable fractions showed no decrease in AhR agonist activity during the treatment but rather an up-going trend, which was supported by increasing levels of PAHs and an increased effect in the Comet bioassay after 274 days. The bio-TEQs calculated using the CALUX assay were higher than the TEQs calculated from chemical analysis in both extracts, indicating that there are additional toxic PAHs in both extracts that are not included in the chemically derived TEQ. Discussion  The response in the CALUX and the Comet bioassays as well as the chemical analysis indicate that the soil might be more toxic to organisms living in soil after 274 days of treatment than in the untreated soil, due to the release of previously sorbed PAHs and possibly also metabolic formation of novel toxicants. Conclusions  Our results put focus on the issue of slow degradation rates and bioavailability of PAHs during large-scale bioremediation treatments. The release of sorbed PAHs at the investigated PAH-contaminated site seemed to be faster than the degradation rate, which demonstrates the importance of considering the bioavailable fraction of contaminants during a bioremediation process. Recommendations and perspectives  It has to be ensured that soft remediation methods like biodegradation or the natural remediation approach do not result in the mobilization of toxic compounds including more mobile degradation products. For PAH-contaminated sites this cannot be assured merely by monitoring the 16 target PAHs. The combined use of a battery of biotests for different types of PAH effects such as the CALUX and the Comet assay together with bioavailability extraction methods may be a useful screening tool of bioremediation processes of PAH-contaminated soil and contribute to a more accurate risk assessment. If the bioremediation causes a release of bound PAHs that are left undegraded in an easily extracted fraction, the soil may be more toxic to organisms living in the soil as a result of the treatment. A prolonged treatment time may be one way to reduce the risk of remaining mobile PAHs. In critical cases, the remediation concept might have to be changed to ex situ remediation methods.     

Population exposure and mortality due to regional background PM in Europe – Long-term simulations of source region and shipping contributions

This paper presents the contribution to population exposure (PE) of regional background fine primary (PPM_2.5) and secondary inorganic (SIA) particulate matter and its impact on mortality in Europe during 1997–2003 calculated with a chemistry transport model. Contributions to concentrations and PE due to emissions from shipping, Western (WEU), Eastern (EEU), and Northern Europe are compared.WEU contributes about 40% to both PPM_2.5 and SIA concentrations, whereas the EEU contribution to PPM_2.5 is much higher (43% of total PPM_2.5) than to SIA (29% of total SIA). The population weighted average concentration (PWC) of PPM_2.5 is a factor of 2.3 higher than average (non-weighted) concentrations, whereas for SIA the PWC is only a factor 1.6 higher. This is due to PPM_2.5 concentrations having larger gradients and being relatively high over densely populated areas, whereas SIA is formed outside populated areas. WEU emissions contribute relatively more than EEU to PWC and mortality due to both PPM_2.5 and SIA in Europe.The number of premature deaths in Europe is estimated to 301 000 per year due to PPM_2.5 exposure and 245 000 due to SIA, despite 3.3 times higher average SIA concentrations. This is due to population weighting and assumed (and uncertain) higher relative risk of mortality for PPM_2.5 components (2.8 times higher RR for PPM_2.5). This study indicates that it might be more efficient, for the health of the European population, to decrease primary PM emissions (especially in WEU) than to decrease precursors of SIA, but more knowledge on the toxicity of different PM constituents is needed before firm conclusions can be drawn.     

Effect of temperature and light on the growth of micro- nano- and pico-plankton: impact on algal succession

The influence of light and temperature on the phytoplankton succession in a temperate sea area was investigated in laboratory experiments with natural assemblages of micro-, nano-, and picoplankton collected from the northern Baltic Sea during 1989 and 1990. Respiration increased from 0 to 30°C in all groups of phytoplankton, while gross photosynthesis stabilised at 10 to 15°C. Light saturation occurred at 25 to 75 mol quanta m^-2 s^-1, indicating low light adaptation of the algae. Picoplankton showed the strongest temperature response, and at temperatures above 10°C picoplankton obtained a higher biomass specific photosynthesis than that of the other groups. Different light treatments had no effect on the species composition in experiments with natural algal assemblages, while different temperature conditions had a marked effect. With a temperature increase from 0 to 10°C, the algal community changed from a typical spring community, with diatoms and dinoflagellates, to a summer community, dominated by mixotrophic nanoflagellates. The small, or often non-existing, autumn bloom in the sea area studied, can be explained by short day lengths combined with relatively high temperatures, causing high community respiration rates and low gross photosynthesis, resulting in a negative energy balance. The net energy gain depends on a differential temperature effect on gross photosynthesis and endogenous respiration in various plankton groups. This gives the phytoplankton groups diverse competitive advantages during different seasons and thus may be an important factor in controlling algal succession.     

Synthesis of Cl2- to Cl4-diphenylsulfides and Cl1- to Cl3-dibenzothiophenes

The synthesis of eleven environmentally relevant mono-, di- and trichlorodibenzothiophenes (2) by photochemical ring-closure of polychlorodiphenylsulfides (1) is described. All monochlorodibenzothiophenes were additionally synthesized starting with a chlorothiophenol in a three-step reaction adapted from the synthesis of methyldibenzothiophenes.     

Urban aerosol evolution and particle formation during wintertime temperature inversions

Aerosol temporal and spatial distributions during wintertime temperature inversions in Gothenburg, Sweden, have been characterized by ground-based and airborne particle measurements combined with lidar measurements. Ground inversions frequently developed during evenings and nights with stable cold conditions, and the low wintertime insolation often resulted in near neutral boundary layer conditions during day-time. Under these conditions ground level aerosol concentrations peaked during morning rush hours and often remained relatively high throughout the day due to inefficient ventilation. The particle number concentrations decreased slowly with increasing altitude within the boundary layer, and measurements slightly above the boundary layer suggested limited entrainment of polluted air into the free troposphere. High concentrations of ultrafine particles were observed throughout the boundary layer up to altitudes of 1100 m, which suggested that nucleation took place within the residual layer during the night and early morning. Recently formed particles were also observed around midday when the layer near ground was ventilated by mixing into the boundary layer, which indicated that ultrafine particles were either transported down from the residual layer to ground level or formed when the polluted surface layer mixed with the cleaner air above.     

Are individual NOEC levels safe for mixtures? A study on mixture toxicity of brominated flame-retardants in the copepod Nitocra spinipes

In aquatic ecosystems organisms are exposed to mixtures of pollutants. Still, risk assessment focuses almost exclusively on effect characterization of individual substances. The main objective of the current study was therefore to study mixture toxicity of a common group of industrial substances, i.e., brominated flame-retardants (BFRs), in the harpacticoid copepod Nitocra spinipes. Initially, 10 BFRs with high hydrophobicity but otherwise varying chemical characteristics were selected based on multivariate chemical characterization and tested individually for effects on mortality and development using a partial life cycle test (six days) where silica gel is used as a carrier of the hydrophobic substances. Based on these findings, six of the 10 BFRs were mixed in a series of NOEC proportions (which were set to 0.008, 0.04, 0.2, 1, and five times the NOEC concentrations for each individual BFR), loaded on silica gel and tested in a full life cycle test (26 days). Significantly increased mortality was observed in N. spinipes after six and 26 days exposure at a NOEC proportion that equals the NOEC LDR value (x1) for each BFR in the mixture (p=0.0015 and p=0.0105, respectively). At the NOECx5 proportion all animals were dead. None of the other NOEC proportions caused significant negative responses related to development and reproduction. This shows that low concentrations of individual substances can cause toxicity if exposed in mixtures, which highlights the need to consider mixture toxicity to a greater extent in regulatory work.     

Relationships between colored dissolved organic matter and dissolved organic carbon in different coastal gradients of the Baltic Sea

Due to high terrestrial runoff, the Baltic Sea is rich in dissolved organic carbon (DOC), the light-absorbing fraction of which is referred to as colored dissolved organic matter (CDOM). Inputs of DOC and CDOM are predicted to increase with climate change, affecting coastal ecosystems. We found that the relationships between DOC, CDOM, salinity, and Secchi depth all differed between the two coastal areas studied; the W Gulf of Bothnia with high terrestrial input and the NW Baltic Proper with relatively little terrestrial input. The CDOM:DOC ratio was higher in the Gulf of Bothnia, where CDOM had a greater influence on the Secchi depth, which is used as an indicator of eutrophication and hence important for Baltic Sea management. Based on the results of this study, we recommend regular CDOM measurements in monitoring programmes, to increase the value of concurrent Secchi depth measurements.     

Evaluation of Multi-level Social Learning for Sustainable Landscapes: Perspective of a Development Initiative in Bergslagen, Sweden

To implement policies about sustainable landscapes and rural development necessitates social learning about states and trends of sustainability indicators, norms that define sustainability, and adaptive multi-level governance. We evaluate the extent to which social learning at multiple governance levels for sustainable landscapes occur in 18 local development initiatives in the network of Sustainable Bergslagen in Sweden. We mapped activities over time, and interviewed key actors in the network about social learning. While activities resulted in exchange of experiences and some local solutions, a major challenge was to secure systematic social learning and make new knowledge explicit at multiple levels. None of the development initiatives used a systematic approach to secure social learning, and sustainability assessments were not made systematically. We discuss how social learning can be improved, and how a learning network of development initiatives could be realized.     

Social and Cultural Sustainability: Criteria, Indicators, Verifier Variables for Measurement and Maps for Visualization to Support Planning

Policies on economic use of natural resources require considerations to social and cultural values. In order to make those concrete in a planning context, this paper aims to interpret social and cultural criteria, identify indicators, match these with verifier variables and visualize them on maps. Indicators were selected from a review of scholarly work and natural resource policies, and then matched with verifier variables available for Sweden’s 290 municipalities. Maps of the spatial distribution of four social and four cultural verifier variables were then produced. Consideration of social and cultural values in the studied natural resource use sectors was limited. The spatial distribution of the verifier variables exhibited a general divide between northwest and south Sweden, and regional rural and urban areas. We conclude that it is possible to identify indicators and match them with verifier variables to support inclusion of social and cultural values in planning.