Extractability of metals and ecotoxicity of soils from two old wood impregnation sites in Finland

Four metal-contaminated soil samples were classified using physical methods, extracted by selective extraction procedures and analyzed for chemical concentrations. De-ionized water, 0.01 mol/l barium chloride, 1 mol/l ammonium acetate and concentrated nitric acid were used as extraction solutions. Ecotoxicity of water extracts and soil samples was analyzed in order to describe the bioavailability of the contaminants. Samples from old wood impregnation plants contained high amounts of As, Cu, Cr and Zn, which originated from chromated copper arsenate, ammoniacal copper-zinc arsenate, and ammoniacal copper quaternary compound. Total As concentrations of the heavily contaminated samples varied from 752 to 4340 mg/kg, Cu concentrations from 339 to 2330 mg/kg, Cr concentrations from 367 to 2,140 mg/kg and Zn concentrations from 79 to 966 mg/kg. The extractabilities of metals differed according to soil type, extractant and element. Cu and Zn were proposed to cause the highest toxicity in the water extracts of the soils. Ecotoxicity tests displayed rather high differences in sensitivity both for water extracts and for solid soil samples. Reproduction of Enchytraeus sp. was the most sensitive and seed germination of Lactuca sativa the least sensitive and the other tests were in decreasing order of sensitivity: Folsomia candida>reverse electron transport>MetPLATE>Toxichromotest>Allium cepa root growth>Lemna sp. growth. As a conclusion, polluted soils rich in sand retain heavy metals with less firm bindings, particularly in the case of Cu and Zn, than soils rich in clay, indicating that chemical methods for measuring the bioavailability of metals need to be optimized taking into account the soil type, acidity, redox state and the individual contaminants.     

A new heart rate variability-based method for the estimation of oxygen consumption without individual laboratory calibration: application example on postal workers

Traditionally, the estimation of oxygen consumption (VO2) at work using heart rate (HR) has required the determination of individual HR/VO2 calibration curves in a separate exercise test in a laboratory (VO2-TRAD). Recently, a new neural network-, and heart rate variability-based method has been developed (Firstbeat PRO heartbeat analysis software) for the estimation of VO2 without individual calibration (VO2-HRV). In the present study, the VO2-values by the VO2-HRV were compared with the values by VO2-TRAD in 22 postal workers. Within individuals the correlation between the two methods was high (range 0.80-0.99). The VO2-TRAD gave higher values of VO2 compared to VO2-HRV (19%) especially during low physical activity work when non-metabolic factors may increase HR. When assessed in different HR categories, the smallest difference (11%), and highest correlations (range 0.83-0.99) in VO2 between the methods were observed at higher HR levels. The results indicate that the VO2-HRV is a potentially useful method to estimate VO2 in the field without laboratory calibration.     

High level of antimicrobial resistance in Campylobacter jejuni isolated from broiler chickens in Estonia in 2005 and 2006

The development of antimicrobial resistance in Campylobacter jejuni and Campylobacter coli is a matter of increasing concern. Because campylobacteriosis is transmitted to humans usually via food of animal origin, the presence of antimicrobial-resistant campylobacters in broiler chickens has important public health implications. The aim of our study was to analyze resistance patterns of C. jejuni isolated from fecal samples collected at a large Estonian chicken farm, from cecal contents collected at slaughterhouses, and from meat samples collected at the retail establishments in 2005 and 2006. A total of 131 C. jejuni isolates were collected over a 13-month period and tested by the broth microdilution VetMIC method (National Veterinary Institute, Uppsala, Sweden) to determine the MICs of various antimicrobials. Resistance to one or more antimicrobials was detected in 104 (79.4%) of the 131 isolates. High proportions of the isolates were resistant to enrofloxacin (73.3%) and nalidixic acid (75.6%). Multidrug resistance (resistance to three or more unrelated antimicrobials) was detected in 36 isolates (27.5%), all of which were resistant to enrofloxacin. Multidrug resistance was significantly associated with enrofloxacin resistance (P < 0.01), and the use of enrofloxacin may select for multiresistant strains.     

Determination of wine amines by HPLC using automated precolumn derivatisation with o-phthalaldehyde and fluorescence detection

Summary A method was developed for the determination of the most important wine amines, histamine, tyramine, putrescine, cadaverine, isoamylamine und-phenethylamine in wine. Amine derivatives were formed automatically by drawing 1 l of wine, 1 l ofo-phthalaldehyde reagent and 5 l of pH 10.4 buffer solution into an injection needle. The reactants were mixed by drawing the liquid back and forth in the needle for 2 min. The derivatives were determined by liquid chromatography using the reversed-phase technique and fluorescence detection. The detection limit for amines ranged from 0.006 to 0.05 mg/L and the determination limit for amines in wine ranged from 0.5 to 1 mg/L, depending on the amine. The total time required by the analysis is 30 min.

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Automatisierung der Bestimmung von Weinaminen mit Hilfe der in der Injektionsspritze erfolgenden OPA-Derivatbildung und Fluorescenz-Flüssigchromatographie

Zusammenfassung In der Untersuchung wurde eine Methode für die wichtigsten im Wein vorkommenden Amine entwickelt: Histamin, Tyramin, Putrescin, Cadaverin, Isoamylamin und-Phenethylamin. Von den zu bestimmenden Aminen wurden durch Aufnahme von 1 l Wein, 1 l OPA-Reagens und 5 l Pufferlösung, pH 10,4, in der gleichen Injektionsspritze deren Derivate gebildet. Die Reaktionspartner wurden durch 2 min Hin- und Herziehen in der Spritze miteinander vermischt. Die Bestimmung der Derivate erfolgte flüssigchromatographisch unter Anwendung von Umkehrphasentechnik und Fluorescenznachweis. Die Nachweisgrenze der Aminen variierte je nach Amin zwischen 0,006 und 0,05 mg/L und die entsprechende Bestimmungsgrenze im Wein zwischen 0,5 und 1 mg/L. Die für die Analyse benötigte Gesamtzeit beträgt 30 min.