Sulfur Metabolism in Polluted Sphagnum Peat Bogs: A Combined 34S–35S–210Pb Study

The size and isotopic behavior of sulfur pools in²¹⁰Pb-dated peat cores were investigated to obtain aninsight into retention mechanisms of pollutant S in twomountain-top peatlands of the Northern Czech Republic, CentralEurope. The bogs were situated 40 km apart in an area whichbetween the years 1985 and 1995 received as much as 130 kg Sha^-1 yr^-1 from the atmosphere. Vertical peataccretion was faster at Pod Jelení horou (JH) than atVelký moál (VM). Organic carbon-bonded S was themost abundant sulfur pool, constituting 77 and 65 wt. % at JHand VM, respectively. At JH both the S concentration maximumand the highest annual S deposition rate were displaceddownward by more than 20 years (from 1987 to the 1960s)indicating that the buried S is vertically mobile. At VM the Sconcentration was the highest in the topmost 2-cm section eventhough atmospheric S deposition peaked in 1987. Differentmechanisms of S isotope redistribution prevailed in thetopmost peat layers at JH, where a negative ³⁴Sshift occurred, and at VM, where a positive ³⁴Sshift occurred. Bacterial sulfate reduction was responsiblefor the negative ³⁴S shift at JH. One possibleexplanation of the positive ³⁴S shift at VM isrelease of ³²S-enriched products of mineralization duringpeat diagenesis. There was a strong positive correlationbetween the abundance of total and pyrite S along the profiles.The presence of pyrite S at VM (526 ± 60 ppm) suggestedthat even at VM bacterial sulfate reduction occurred. Ananaerobic incubation of JH peat indicated sulfate reductionrate of 600 nmol g^-1 day^-1. The turnover times forinorganic S pools were shorter than for the organic S pools.Cumulative S contents in the Czech peat bogs were found to besignificantly lower than in similar sites in the NortheasternU.S., even though the atmospheric S inputs were more thanthree times higher at the Czech sites. Possible causes of suchdiscrepancy are discussed.     

How to Preserve Coastal Wetlands,Threatened by Climate Change-Driven Rises in Sea Level

A habitat transition model, based on the correlation between individual habitats and micro-elevation intervals, showed substantial changes in the future spatial distributions of coastal habitats. The research was performed within two protected areas in Slovenia: Se?ovlje Salina Nature Park and ?kocjan Inlet Nature Reserve. Shifts between habitats will occur, but a general decline of 42 % for all Natura 2000 habitats is projected by 2060, according to local or global (IPCC AR4) sea level rise predictions. Three different countermeasures for the long-term conservation of targeted habitat types were proposed. The most “natural” is displacement of coastal habitats using buffer zones (1) were available. Another solution is construction of artificial islets, made of locally dredged material (2); a feasible solution in both protected areas. Twenty-two islets and a dried salt pan zone at the desired elevations suitable for those habitats that have been projected to decease in area would offer an additional 10 ha in the Se?ovlje Salina. Twenty-one islets and two peninsulas at two different micro-altitudes would ensure the survival of 13 ha of three different habitats. In the area of Se?ovlje Salina, abandoned salt pans could be terrestrialized by using permanent, artificial sea barriers, in a manner close to poldering (3). By using this countermeasure, another 32 ha of targeted habitat could be preserved. It can be concluded that, for each coastal area, where wetland habitats will shrink, strategic plans involving any of the three solutions should be prepared well in advance. The specific examples provided might facilitate adaptive management of coastal wetlands in general.     

The in vitro effect of selected essential oils on the growth and mycotoxin production of Aspergillus species

The aim of the present study was to assess the antifungal and anti-toxinogenic activity of 15 essential oils (EOs) against three fungi of the genus Aspergillus (A. parasiticus KMi-227-LR, A. parasiticus KMi-220-LR and A. flavus KMi-202-LR). The minimum inhibitory doses (MIDs) of the tested essential oils and their antifungal activity were determined using the micro-atmosphere method. The original commercial essential oil samples of Jasminum officinale L., Thymus vulgaris L., Syzygium aromaticum (L.) Merrill &; Perry, Rosmarinus officinalis L., Ocimum basilicum L., Eucalyptus globulus Labill., Salvia officinalis L., Citrus limon (L.) Burm, Origanum vulgare L., Lavandula angustifolia Mill., Carum carvi L., Citrus sinensis (L.) Osbeck., Zingiber officinalis Rosc., Mentha piperita L. and Cinnamomum zeylanicum Nees. (C. verum J.S.Presl.) were produced in Slovakia (Calendula a.s., Nová ?ubovňa, Slovakia). All essential oils exhibited activity against all tested strains of fungi. After 14 days of incubation, A. flavus (KMi-202-LR) showed the highest susceptibility with a growth inhibition percentage (GIP) of 18.70% to C. limon and 5.92% to C. sinensis, while A. parasiticus (KMi-220-LR) exhibited a GIP of 20.56% to J. officinale. The minimum inhibitory doses (MIDs) of EOs with the most significant activity were recorded. The best antifungal activity, using the micro-atmosphere method was found in S. aromaticum with an MID of 62.5 μL L^?1 air, T. vulgaris (MID of 62.5 μL L^?1 air) and O. vulgare (MID of 31.5 μL L^?1 air) against all tested strains. Mycotoxin production of the tested strains was evaluated by the thin layer chromatography (TLC) method. Mycotoxin production of AFB₁ and AFG₁ was inhibited following all treatments with C. carvi, R. officinale and S. officinale, Eucalyptus globulus L. and O. basilicum L. Essential oils exhibited a potential inhibition activity against toxic fungi, although, these affected only the production of AFB₁.     

Utilization of Natural Oils for Decomposition of Polyurethanes

The model polyurethane foam and model compact polyurethane material were prepared and then decomposed by means of natural oils. Castor oil and fish oil based polyol were used in this study. Optimal conditions for the polyurethane decomposition were found. Temperature 250 °C was necessary for efficient polyurethane decomposition by castor oil whereas 200 °C is sufficient in the case of fish oil based polyol. Prepared products have hydroxyl number in the range of 95–168 mg KOH g⁻¹. During the polyurethane decomposition no cleavage of double bonds in the fatty acid chains of castor oil and fish oil based polyol was observed.     

Anaerobic Biodegradation of Blends Based on Polyvinyl Alcohol

The presented work deals with blends composed of polyvinyl alcohol (PVA) and biopolymers (protein hydrolysate, starch, lignin). PVA does not belong to biologically inert plastics but its degradation rate (particularly under anaerobic conditions) is low. A potential solution to the issue problem lies in preparation of blends with readily degradable substrates. We studied degradation of blow-molded films made of commercial PVA and mentioned biopolymers in an aqueous anaerobic environment employing inoculation with digested activated sludge from the municipal wastewater treatment plant. Films prepared in the first experimental series were to be used for comparing biodegradation of blends modified with native or plasticized starch; in this case effect of plasticization was not proved. The degree of PVA degradation after modification with native or plasticized starch increases in a striking and practically same manner already at a starch level as low as approximately 5 wt.%. Films of the second experimental series were prepared as additionally modified with protein hydrolysate and lignin. Only lignin-modified samples exhibited a somewhat lower degree of biodegradation but regarding the measure of lignin present in blend this circumstance is not essential. Level of biodegradation with all discussed films differed only slightly—within range of experimental error.     

Biochemical biomarkers in environmental studies—lessons learnt from enzymes catalase,glutathione <Emphasis Type="Italic">S</Emphasis>-transferase and cholinesterase in two crustacean species

Background, aim and scope  

For reliable environmental risk assessment of pollutants, knowledge on the effects at different levels of biological organisation is needed. During the early days of biomarker research in environmental studies approximately two decades ago, biochemical biomarkers were considered as the most promising tool for such purposes. Among these, three enzymes have often been studied: catalase (CAT), glutathione S-transferase (GST) and cholinesterase (ChE). However, despite their intensive research, their measurements in invertebrates have not been commonly applied in environmental risk assessment (ERA) or for regulatory purposes.     

Mercury in fish tissues in the area of Malachov Hg-ore deposit (Slovakia)

Environmental Geochemistry and Health - The abandoned Malachov deposit belongs among the most important historic Hg deposits in the world. The soil, groundwater, surface water, plants, and animals...     

The Properties of Poly(<Emphasis Type="SmallCaps">l</Emphasis>-Lactide) Prepared by Different Synthesis Procedure

Different synthesis methods were applied to determine optimal conditions for polymerization of (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione (l-lactide), in order to obtain poly(l-lactide) (PLLA). Bulk polymerizations (in vacuum sealed vessel, high pressure reactor and in microwave field) were performed with tin(II) 2-ethylhexanoate as the initiator. Synthesis in the vacuum sealed vessel was carried out at the temperature of 150 °C. To reduce the reaction time second polymerization process was carried out in the high pressure reactor at 100 °C and at the pressure of 138 kPa. The third type of rapid synthesis was done in the microwave reactor at 100 °C, using frequency of 2.45 GHz and power of 150 W at the temperature of 100 °C. The temperature in this method was controlled via infrared system for in-bulk measuring. The solution polymerization (with trifluoromethanesulfonic acid as initiator) was possible even at the temperature of 40 °C, yielding PLLA with narrow molecular weight distribution in a very short period of time (less than 6 h). The obtained polymers had the number-average molecular weights ranging from 43,000 to 178,000 g mol⁻¹ (polydispersity index ranging from 1 to 3) according to the gel permeation chromatography measurements. The polymer structure was characterized by Fourier transform infrared and NMR spectroscopy. Thermal properties of the obtained polymers were investigated using thermogravimetry and differential scanning calorimetry.