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Determination of pentachlorophenol (PCP) in waste wood--method comparison by a collaborative trial 总被引:9,自引:0,他引:9
Two independently developed and validated procedures for the determination of pentachlorophenol (PCP) in waste wood were compared by means of a collaborative trial. Both methods foresee quantification of PCP by gas chromatography (GC-ECD) after acetylation and differ with regard to the use of methanol or toluene/sulphuric acid, respectively, as solvent in the sonication extraction step. Test samples with established analyte homogeneity were prepared from a ground "real life" starting material. A total of 23 participating laboratories with experience in wood preservative analysis were instructed to apply both methods to three levels of content in the range of 0.5-20 mg PCP/kg. In case of the toluene/sulphuric acid extraction, lower recoveries and higher interlaboratory dispersion of results at the higher PCP contents were observed. Seen against the background of the Horwitz equation a reproducibility standard deviation of approximately 19% for the methanol extraction at the 4.5 mg/kg level meets the requirement for a sound analytical method. Thus, the sonication extraction procedure with methanol has been annexed as a reference method to the German waste wood regulation. 相似文献
95.
Although assortative mating is widespread among long-lived monogamous birds, the underlying mechanisms still remain unclear
in many species. In this study, we analysed assortative mating by age and body mass in the common tern Sterna hirundo with special regard to mate choice decisions of newly paired birds. To assess whether assortative mating by age is an active
decision involving either homotypic or directional preferences or rather a passive process due to restricted availability
of potential mates, we analysed the influence of age-dependent arrival date and cohort size. Furthermore, we looked for direct
benefits in terms of reproductive success. Common terns mated assortatively by age and arrival date but not by body mass at
arrival. Assortative mating by age was age dependent and was detected mainly in younger birds, whereas birds older than 8 years
rather re-paired with younger ones. The availability of same-aged mates was restricted by cohort size and arrival date. We
found no general evidence for better reproductive performance of same-aged pairs. Instead, relative reproductive success was
related to own age and the relative age of mate: It should be advantageous for any bird to acquire an old mate; hence, assortative
mating by age seems to be beneficial only for old terns but not for young ones. Age-assortative mating in common terns occurred
by both passive and active processes, which are not mutually exclusive. Our results do not indicate a homotypic but a directional
preference and support the theory that high-quality (older/experienced) individuals tend to mate assortatively if same-aged
mates are available, which leaves low-quality (young/inexperienced) individuals to mate among themselves. 相似文献
96.
A practical method for the quantification of total purgeable organic sulfur (POS) in highly contaminated groundwater is described.
Volatile organic sulfur compounds (VOSC) are purged from the water samples by a stream of oxygen and combusted. The emerging
sulfur dioxide is absorbed in H2O2 and converted to sulfate which is quantified by ion chromatography and reported as mass sulfur equivalent. The overall limit
of quantification is 0.03 mg l−1. The content of POS is balanced with the total VOSC determined by GC-AED after liquid–liquid extraction. Separate determination
of the non-volatile organic sulfur compounds by direct combustion of the water sample and adsorption to charcoal yielded a
mass balance of the total sulfur content. Semi-quantitative GC-MS after purge & trap accumulation revealed that the VOSC mixture
is composed of C1–C4 alkyl sulfides. The implementation of the developed methodology for the quantification of VOSC as potential catalyst poison
in a cleaning plant for groundwater contaminated with volatile haloorganics (VOX) is presented. 相似文献
97.
Correlations between age, phenotype, and individual contribution to population growth in common terns 总被引:2,自引:0,他引:2
There have been numerous reports of changes in phenology, which are frequently attributed to environmental change. Age-dependent change in phenotypic traits, fledgling production, and the timing of events in the life cycle is also widespread. This means that changes in the age structure of a population could generate changes in phenology, which may be incorrectly attributed to environmental change or microevolution. Here, estimates of selection for arrival date, arrival mass, and laying date are compared when age is and is not corrected for. This is achieved using long-term individual-based data collected from a breeding colony of Common Terns (Sterna hirundo) and a novel fitness measure: individual contributions to population growth. The failure to correct for age generated deceptive estimates of selection in eight out of nine comparisons. In six out of nine comparisons, the direction of selection differed between age-corrected and uncorrected estimates. Persistent individual differences were detected: individuals remained within the same part of the phenotype distribution throughout life. The age-corrected estimates of selection were weak and explained little variation in fitness, suggesting that arrival date, arrival mass, and laying date are not under intense selection in this population. These results also demonstrate the importance of correcting for age when identifying factors associated with changes in seabird phenology. 相似文献
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99.
Veith Becker Anssi Myrttinen Philipp Blum Robert van Geldern Johannes A.C. Barth 《International Journal of Greenhouse Gas Control》2011,5(5):1250-1258
Stable carbon isotopes are important tools to assess potential storage sites for CO2, as they allow the quantification of ionic trapping via isotope mass balances. In deep geological formations high p/T conditions need to be considered, because CO2 dissolution, equilibrium constants and isotope fractionation of dissolved inorganic carbon (DIC) depend on temperature, pressure and solute composition. After reviewing different approaches to account for these dependencies, an expanded scheme is presented for speciation and carbon isotope fractionation of DIC and dissolution of CaCO3 for pCO2 up to 100 bar, pH down to 3 and temperatures of up to 200 °C. The scheme evaluates the influence of respective parameters on isotope ratios during CO2 sequestration. The pCO2 and pH are the dominant controlling factors in the DIC/δ13C/pH system. The fugacity of CO2 has major impact on DIC concentrations at temperatures below 100 °C at high pCO2. Temperature dependency of activities and equilibrium dominates at temperatures above 100 °C. Isotope ratios of DIC are expected to be about 1–2‰ more depleted in 13C compared to the free CO2 at pCO2 values above 10 bar. This depletion is controlled by carbon isotope fractionation between CO2 and H2CO3* which is the dominant species of DIC at the resulting pH below 5. 相似文献
100.
Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent and widely distributed in the environment. Recently, the discharge of municipal waste water has been shown to be an important route of such perfluoroalkyl surfactants into the aquatic environment. The aim of this study was to assess the mass flow of PFOA and PFOS from typical waste water treatment plants (WWTPs) into surface waters. Samples were collected at different stages of treatment of four WWTPs in Northern Bavaria, Germany, and from the rivers receiving the treated waste waters (WW). The outflow of PFOA from the WWTPs to the rivers was 20-fold higher than the inflow to the plants; about a tenth was removed with the sludge. For PFOS, the increase from inlet to outlet was about 3-fold; almost half of it was retained in the sludge. Both surfactants were released into river water from the WWTP of a medium-sized city with domestic, industrial and commercial waste waters; in domestic waste waters the surfactants were found at much lower levels. 相似文献