Measurements in the raw gas of a full scale municipal waste incinerator using a wavelength resolved REMPI mass spectrometer

A resonance enhanced multiphoton ionization (REMPI) mass spectrometer consisting of a tunable laser unit (Nd:YAG pump laser and OPO) and a reflectron mass spectrometer have been upgraded to cope with the difficult conditions such as vibrations, temperature fluctuations and dust, prevailing in an incinerator. On-line measurements of the raw gas have been carried out at the municipal waste incinerator in Stuttgart. Although this test series could not be completed the results are encouraging. They show that wavelength resolution can provide valuable information beyond the one obtainable by fixed frequency REMPI. Examples discussed include separation of interferants to the aniline signal and identification of phenantrene.     

Chelator induced phytoextraction and in situ soil washing of Cu

In a soil column experiment, we investigated the effect of 5 mmol kg(-1) soil addition of citric acid, ethylenediamine tetraacetate (EDTA), diethylenetriamine-pentaacetate (DTPA) and [S,S]-stereoisomer of ethylenediamine-disuccinate (EDDS) on phytoextraction of Cu from a vineyard soil with 162.6 mg kg(-1) Cu, into the test plant Brassica rapa var. pekinensis. We also examined the use of a horizontal permeable barrier, composed of layers of nutrient enriched sawdust and apatite, for reduction of chelator induced Cu leaching. The addition of all chelators, except citric acid, enhanced Cu mobility and caused leaching of 19.5-23% of initial total Cu from the soil column. However, Cu plant uptake did not increase accordingly; the most effective was the EDDS treatment, in which plant Cu concentration reached 37.8 +/-1.3 mg kg(-1) Cu and increased by 3.3-times over the control treatment. The addition of none of the chelators in the concentration range from 5 to 15 mmol kg(-1) exerted any toxic effect on respiratory soil microorganisms. When EDDS was applied into the columns with horizontal permeable barriers, only 0.53 +/- 0.32% of the initial total Cu was leached. Cu (36.7%) was washed from the 18 cm soil layer above the barrier and accumulated in the barrier. Our results indicate that rather than for a reduction of Cu leaching during rather ineffective chelate induced Cu phytoextraction, horizontal permeable barriers could be more effective in a new remediation technique of controlled in situ soil washing of Cu with biodegradable chelates.     

Seasonal variability of mercury and heavy metals in roe deer (Capreolus capreolus) kidney

The seasonal variability of Hg, Pb, Cd and Zn was determined in the kidney of 164 roe deer, shot in three areas of Slovenia in 1998. We found a strong seasonal influence on Hg and Pb levels, which were significantly higher in late summer and early autumn. Cd and Zn levels showed a similar seasonal pattern, although not so pronounced; for these elements differences among periods were probably not a consequence of season per se. Seasonal variability in metal levels in roe deer kidney originated in both quantitative and qualitative differences in nutrition of the species. Since the seasonal peaks for the majority of metals appeared in a very narrow summer autumnal period (August-September), it seems that some plant taxons, such as fungi, might represent an important pathway for heavy metal intake into the mammalian organism. The season of sample collection has to be considered whenever using wildlife as an accumulative bioindicator of environmental pollution. Moreover, the influence of the season should be born in mind whenever a hazard due to accumulation of heavy metals along the food chain is assessed.     

Chemical composition and hygroscopic properties of size-segregated aerosol particles collected at the Adriatic coast of Slovenia

The chemical composition as well as the water uptake characteristics of aerosols was determined in size-segregated samples collected during November 2002 on the Slovenian coast. Major ions, water-soluble organic compounds (WSOC), short-chain carboxylic acids and trace elements were determined in the water-soluble fraction of the aerosol. Total aerosol black carbon (BC) was measured from filter samples. Our results showed that the origin of air masses is an important factor that controls the variation in the size distribution of the main components. Very high concentrations of WSOC as well as higher concentrations of BC were found under mostly continental influence. Besides the main ionic species (SO4(2-), NH4(+), K+) in the finest size fraction (0.17-0.53 microm), the concentration of NO3(-) was also high. The difference between the two different air mass origins is particularly expressed for Cl-, Na+, Mg2+ and Ca2+ determined in particles larger than 1.6 microm. As expected, a very good correlation was found between Na+ and Cl-. A good correlation was found between sea salt elements and elements of crustal origin (Na+, Cl-, Mg2+, Ca2+, Sr). A good relationship between typical anthropogenic tracers (K, V and Pb) was also observed. The mass growth factors, for all size fractions of aerosols collected under continental influence were very low (maximum 2.23 at 94%, 1.6-5.1 microm), while under marine influence the mass growth factors increased significantly with the particle size. At 97% humidity, the mass growth factors were 6.95 for the size fraction 0.53-1.6 microm and 9.78 for larger particles (1.6-5.1 microm).     

Heavy metals and arsenic concentrations in ten fish species from the Šalek lakes (Slovenia): assessment of potential human health risk due to fish consumption

The study, which measured the concentrations of Hg, Pb, Cd, Zn and As in various fish tissues (muscle, gill and liver) of 10 fish species (Abramis brama danubii, Alburnus alburnus alburnus, Barbus meridionalis petenyi, Carassius auratius gibelio, Cyprinus carpio, Lepomis gibossus, Leuciscius cephalus cephalus, Perca fluviatilis fluviatilis, Rutilus rutilus, Scardinus erythrophtlalmus erythrophtlalmus) collected in the Šalek lakes, is the first survey regarding metal concentrations in fish species with samples originating from Slovene lakes, while only a limited number of such studies have been carried out in southeastern Europe. Since these lakes are situated in the close vicinity of the largest Slovene thermal power plant, the study provides an insight into the potential impact of increased levels of metals in the environment as well as an estimate of the contamination of fish tissues with metals. Furthermore, it was possible to compare the results obtained with those from other studies regarding metal levels in freshwater fish species. The mean metal concentrations of different tissues irrespective of species varied in the following ranges: Zn 4.31–199 mg/kg ww, Pb 0.01–0.48 mg/kg ww, As 0.02–0.44 mg/kg ww, Hg <0.01–0.31 mg/kg ww, Cd < 0.01–0.19 mg/kg ww. In general, higher contents of Hg were found in muscles and livers than in gills and higher contents of As in gills and livers than in muscles, respectively. The accumulation of Pb and Zn was most pronounced in gills. The result obtained regarding metal concentrations in fish revealed that the ecosystems of the Šalek lakes are not polluted with Hg and Pb, slightly loaded with As and Cd and moderately polluted with Zn. In addition, the potential human health risk due to fish consumption was assessed. This showed that the estimated weekly intakes for all metals were far below provisional permissible tolerable weekly intakes determined by WHO/FAO. The consumption of fish from the Šalek lakes, therefore, does not pose a risk to human health.     

Determination of sulfur oxides formed during the S(IV) oxidation in the presence of iron

The reaction products (i.e., sulfate (SO4(2-)) and dithionate (S2O6(2-))) of S(IV) oxidation in the presence of iron(III) under different experimental conditions were investigated. Ion-interaction chromatography was used for the separation of sulfate and dithionate using tetrabutylammonium hydroxide (TBAOH) as an ion-pair reagent. The chromatographic method was optimized by varying the composition of the mobile phase (i.e., concentration of TBAOH, acetonitrile and Na2CO3) and by varying the flow rate of the mobile phase. The method was successfully applied to the determination of dithionate formed during the S(IV) oxidation in the presence of Fe(III). In air-saturated solutions sulfate was observed as the only product, while in N2-saturated solutions dithionate was also determined, but it is the minor reaction product and represents about 4% of the total amount of oxidized HSO3- under the studied conditions.     

Mass spectrometry up to 1 million mass units for the simultaneous detection of primary soot and of soot precursors (nanoparticles) in flames

A hybrid setup consisting of low pressure burner, flow reactor and photo-ionization mass spectrometer was used for the simultaneous detection of primary soot and of flame generated nanoparticles precursing soot. The studied flames were low pressure (120-180 mbar) C2H4/O2 flames surrounded by an N2 shield. The flow reactor was not used in this study. Through variation of the burner conditions (stoichiometry, sampling height) it could be shown that nanoparticles and soot are entirely independent species. The former, in particular, are found very early in the flame and their concentration profiles do not vary very much throughout the flame. This renders the possibility that nanoparticles are emitted together with soot and consequently may constitute an additional environmental hazard. Photo-ionization mass spectrometry is well suited for the detection of these particles.     

Forest frontiers out of control: The long-term effects of discourses,policies, and markets on conservation and development of the Brazilian Amazon

With the Brazilian military governments of the 1960s, systematic economic development of the Amazon began. Social and environmental concerns have entered Amazonian discourses and policies only since the 1990s. Since then, reports of threats to forests and indigenous people have alternated with reports of socio-economic progress and environmental achievements. These contradictions often arise from limited thematic, sectoral, temporal, or spatial perspectives, and lead to misinterpretation. Our paper offers a comprehensive picture of discourses, policies, and socio-environmental dynamics for the entire region over the last five decades. We distinguish eight historical policy phases, each of which had little effect on near-linear dynamics of demographic growth and land-use expansion, although some policies showed the potential to change the course of development. To prevent local, national, and international actors from continuing to assert harmful interests in the region, a coherent long-term commitment and change in the collective mindset are needed.     

Grassland invader responses to realistic changes in native species richness.

The importance of species richness for repelling exotic plant invasions varies from ecosystem to ecosystem. Thus, in order to prioritize conservation objectives, it is critical to identify those ecosystems where decreasing richness will most greatly magnify invasion risks. Our goal was to determine if invasion risks greatly increase in response to common reductions in grassland species richness. We imposed treatments that mimic management-induced reductions in grassland species richness (i.e., removal of shallow- and/or deep-rooted forbs and/or grasses and/or cryptogam layers). Then we introduced and monitored the performance of a notorious invasive species (i.e., Centaurea maculosa). We found that, on a per-gram-of-biomass basis, each resident plant group similarly suppressed invader growth. Hence, with respect to preventing C. maculosa invasions, maintaining overall productivity is probably more important than maintaining the productivity of particular plant groups or species. But at the sites we studied, all plant groups may be needed to maintain overall productivity because removing forbs decreased overall productivity in two of three years. Alternatively, removing forbs increased productivity in another year, and this led us to posit that removing forbs may inflate the temporal productivity variance as opposed to greatly affecting time-averaged productivity. In either case, overall productivity responses to single plant group removals were inconsistent and fairly modest, and only when all plant groups were removed did C. maculosa growth increase substantially over a no-removal treatment. As such, it seems that intense disturbances (e.g., prolonged drought, overgrazing) that deplete multiple plant groups may often be a prerequisite for C. maculosa invasion.