Trends in background levels of persistent organic pollutants at Kosetice observatory, Czech Republic.1) Part I. Ambient air and wet deposition 1996-2005

Kosetice observatory is a facility of the Czech Hydrometeorological Institute, which is a part of the European Monitoring and Evaluation Programme (EMEP) network. Persistent organic pollutants (POPs: PCBs, DDTs, HCHs, PAHs) have been monitored in all environmental matrices using the integrated monitoring approach. Generally, the atmospheric levels of POPs in this Central European background station (mean values: 0.115 ng m(-3) for SigmaPCBs, 0.040 ng m(-3) for SigmaDDTs, 0.077 ng m(-3) for SigmaHCHs, and 17 ng m(-3) for SigmaPAHs) are significantly higher than those in other EMEP stations localized mostly in Northern and Western Europe. Long-term trends of POP concentrations in the ambient air and wet deposition are presented in this article and they show a slow decline in the last decade for most of the investigated compounds. Temporally increased levels of certain chemicals were associated with some local climatic (floods) or socio-economic (fuel prices) factors.     

Vegetation succession and lichen diversity on dry coastal calciumpoor dunes and the impact of management experiments

The negative impact of grass and moss encroachment on the botanical diversity of West European coastal dunes attracted increasing attention in the 1990s. This paper focuses on moss encroachment during primary succession in the xeroseries. Until the mid-1970s, vegetation types rich in species of the lichen generaCladonia andCladina were found on the fixed,Corynephorus canescens-dominated, so-called grey dunes all over the island of Terschelling, The Netherlands. In addition, species ofHypogymnia, Parmelia andUsnea, which usually grow on trees, occurred here terrestrially on moss carpets or bare sand. These vegetation types are still present on the Noordsvaarder, a nature reserve in the western part of the island. They occur on parts of seven dune ridges parallel to the coast and form a chronosequence in which age increases with distance from the sea. Our study found the highest lichen diversity on the second and third dune ridges in a stage of primary succession that can be assigned to theViolo-Corynephoretum. The changes from lichen-rich to moss-dominated stadia were significantly related to soil development and acidification in connection with the ageing of the dune soil. The superficial cutting of sods in moss-encroached vegetation appeared to be unsuccessful as a management technique for restoring the biodiversity of cryptogams. Our findings suggest that the best option for maintaining lichen vegetation in theViolo-Corynephoretum is the blow-in of sand with a subneutral or neutral pH from reactivated and natural blowouts or from foredunes, with increasing lime content respectively. Nomenclature: Van der Meijden (1990) for higher plants; Touw & Rubers (1989) for mosses; Purvis et al. (1992) for lichens. A set of lichen specimens has been deposited at the herbarium of Dr. A. Aptroot (C.B.S. Baarn) — herbarium code ABL (Taxon 44: 258).     

Antimony availability in highly polluted soils and sediments - a comparison of single extractions

Forest/tilled soils and stream sediments from the highly polluted mining and smelting district of Príbram, Czech Republic, were subjected to single extraction procedures in order to determine the available contents of Sb and As. The results obtained from five widely-used 2-h single extraction tests were compared: deionised water, 0.01M CaCl(2), 1M NH(4)NO(3), 0.005M diethylentriaminpentaacetic acid (DTPA) and 0.1M Na(2)HPO(4). The ICP-MS determinations of Sb and As in the extracts were coupled with measurements of pH and Eh and geochemical modelling (PHREEQC-2) to determine their speciation in extracts and possible solubility-controlling phases. According to the speciation calculations, Sb in extracts was present mainly as Sb(V) with the exception of the DTPA extracts from highly organic and acidic forest soils, where Sb(III) species accounted for up to 34% of total Sb speciation. The highest extractabilities were observed for the 0.1M Na(2)HPO(4) solution (up to 9% of the total Sb and up to 34% of the total As concentration). The other extracting media yielded statistically the same results (p<0.05) with Sb extractabilities below 2% and As extractabilities below 8%. Thus, simple deionised water and 0.1M Na(2)HPO(4) extractions are preferred for quick estimates of easily-exchangeable and specifically-sorbed Sb, respectively.     

Inactivation of bacteria by sun light in a solar reactor with Immobilised TiO2

The photocatalytical inactivation of bacteria (Escherichia coli, Staphylococcus epidermidis,...) in the flow‐through plate solar reactor by sunlight was investigated. The low stability of bacteria in the reactor was attributed to bacteria sensitivity to mixing and/or gas bubbling. Sunlight inactivation proceeds with sufficient rate even under cloudy conditions.     

Detection of Listeria monocytogenes in ready-to-eat food by Step One real-time polymerase chain reaction

The aim of this study was to follow contamination of ready-to-eat food with Listeria monocytogenes by using the Step One real time polymerase chain reaction (PCR). We used the PrepSEQ Rapid Spin Sample Preparation Kit for isolation of DNA and MicroSEQ? Listeria monocytogenes Detection Kit for the real-time PCR performance. In 30 samples of ready-to-eat milk and meat products without incubation we detected strains of Listeria monocytogenes in five samples (swabs). Internal positive control (IPC) was positive in all samples. Our results indicated that the real-time PCR assay developed in this study could sensitively detect Listeria monocytogenes in ready-to-eat food without incubation.     

The use of poplar during a two-year induced phytoextraction of metals from contaminated agricultural soils

The efficiency of poplar (Populus nigra L.xPopulus maximowiczii Henry.) was assessed during a two-year chemically enhanced phytoextraction of metals from contaminated soils. The tested metal mobilizing agents were EDTA (ethylenediaminetetraacetic acid) and NH4Cl. EDTA was more efficient than chlorides in solubilizing metals (especially Pb) from the soil matrix. The application of chlorides only increased the solubility of Cd and Zn. However, the increased uptake of metals after the application of higher concentrations of mobilizing agents was associated with low biomass yields of the poplar plants and the extraction efficiencies after the two vegetation periods were thus comparable to the untreated plants. Additionally, the application of mobilizing agents led to phytotoxicity effects and increased mobility of metals. Higher phytoextraction efficiencies were observed for Cd and Zn compared to Pb and Cu. Poplars are therefore not suitable for chemically enhanced phytoextraction of metals from severely contaminated agricultural soils.     

Ozone flux over a Norway spruce forest and correlation with net ecosystem production

Daily ozone deposition flux to a Norway spruce forest in Czech Republic was measured using the gradient method in July and August 2008. Results were in good agreement with a deposition flux model. The mean daily stomatal uptake of ozone was around 47% of total deposition. Average deposition velocity was 0.39 cm s⁻¹ and 0.36 cm s⁻¹ by the gradient method and the deposition model, respectively. Measured and modelled non-stomatal uptake was around 0.2 cm s⁻¹. In addition, net ecosystem production (NEP) was measured by using Eddy Covariance and correlations with O₃ concentrations at 15 m a.g.l., total deposition and stomatal uptake were tested. Total deposition and stomatal uptake of ozone significantly decreased NEP, especially by high intensities of solar radiation.