44 research outputs found
Allometry of the Duration of Flight Feather Molt in Birds
Replacement of flight feathers takes disproportionately more time for large birds than it does for small birds, because feather length increases with body size almost twice as fast as feather growth rate increases
Determination of fat content and fatty acid composition in meat and meat products after supercritical fluid extraction
Two different relatively simple, commercially available supercritical fluid extractors (SFE), Leco and Foss-Tecator, were tested for the determination of total fat content in meat and meat products. The fatty acid composition in meat and meat products was also determined after the Foss-Tecator extraction in an aliquot of the extract. Total fat was determined by weighing after the different extraction procedures and the fatty acid composition by gas chromatography after hydrolysis and methylation of the extract. The results for total fat content agreed well with results from a standard method of Schmid, Bondzynski, and Ratzlaff, which uses conventional solvent extraction. Fatty acid composition was compared with the Bligh and Dyer extraction, and showed good agreement. The average relative difference between SFE and Bligh and Dyer of all fatty acids in the sample was <3% for acids exceeding 0.5% of total fatty acid amount. The advantages of SFE over traditional methods are a much lower consumption of hazardous organic solvents and shorter extraction times. To obtain quantitative recoveries by SFE, ethanol was added to the extraction cells before extraction
Filter-based treatment of leachate from an industrial landfill containing shredder residues of end-of-life vehicles and white goods.
A pilot plant was set up to treat leachate from an industrial landfill containing shredder residues of end-of-life vehicles and white goods. The treatment plant consisted of aeration and sedimentation steps for pre-treatment, and a filter. The plant was designed to simultaneously remove various types of pollutants. The efficiencies of pre-treatment and of the main treatment step were investigated over a period of 3 years at the landfill site. By continuous aeration of the leachate the concentrations of Fe and Mn were reduced by 55% and 49%, respectively. By prolonged sedimentation suspended solid content was noticeably reduced (72%). In the filter, consisting of a mixture of peat and carbon-containing ash as a treatment medium, very high reduction of polar organic compounds, e.g. phenol (74%), o-and p-cresol (91%), and 2,4-dimethylphenol (73%), high average reduction of metals, e.g. Pb (78%), Fe (74%), Cu (73%), Mn (56%), Sn (55%), and Zn (47%), and good average reduction of DOC (26%), Tot-N (23%) and NH(4)-N (46%) were achieved. Sixty non-polar compounds in the leachate, identified by GC-MS screening, occurred at trace level. Most of them were considerably reduced in the filter
Exposure to Metalworking Fluid Aerosols and Determinants of Exposure
Metalworking fluid (MWF) aerosols are associated with respiratory disorders including asthma and hypersensitivity pneumonitis. The aims of this study were to describe exposure to inhalable MWF aerosols and volatile compounds in machine shops, to estimate the influence of important determinants of exposure and to compare different sampling techniques for MWF aerosols. Personal full-shift air samples of inhalable aerosol (PAS-6 sampler) and total aerosol (open-faced sampler) were collected on operators in five medium to big-sized machine shops in three companies. The filters were analysed gravimetrically and extracted by supercritical fluid extraction for MWF aerosol and triethanolamine content. In addition, personal measurements were taken for formaldehyde and volatile compounds on adsorbent samplers. Continuous dust measurements were performed with a real-time instrument (DataRAM) during 2 h periods, using 1-min average values. In total, 95 measurements of inhalable aerosol and extracted MWF aerosols on 51 operators were conducted. Within the companies, the average exposure to inhalable aerosol ranged from 0.19 to 0.25 mg m(-3) with geometric standard deviations from 1.56 to 1.79. On average, the extracted fraction of MWF aerosol was 67% of the inhalable aerosol concentration. The exposure levels of triethanolamine, formaldehyde and volatile compounds were generally low. About 45% of the between-worker variance could be explained by use of compressed air, lack of complete enclosure of machines or grinding as cutting task. In 21 workers with continuous aerosol measurements, short-term peak exposures during 6% of the work time contributed to similar to 25% of the average concentration of inhalable MWF aerosol. Inhalable MWF aerosol concentration measured with the PAS-6 sampler was a factor 2 higher than the concentrations derived from the open-faced sampler. These findings suggest that control measures, such as full enclosure of machines and the elimination of the use of compressed air as cleaning technique, are required to reduce the exposure to MWF aerosols to levels below the expected threshold for adverse respiratory health effects
Defining Pollinator Health: A Holistic Approach Based on Ecological, Genetic, and Physiological Factors
Evidence for global bee population declines has catalyzed a rapidly evolving area of research that aims to identify the causal factors and to effectively assess the status of pollinator populations. The term pollinator health emerged through efforts to understand causes of bee decline and colony losses, but it lacks a formal definition. In this review, we propose a definition for pollinator health and synthesize the available literature on the application of standardized biomarkers to assess health at the individual, colony, and population levels. We focus on biomarkers in honey bees, a model species, but extrapolate the potential application of these approaches to monitor the health status of wild bee populations. Biomarker-guided health measures can inform beekeeper management decisions, wild bee conservation efforts, and environmental policies. We conclude by addressing challenges to pollinator health from a One Health perspective that emphasizes the interplay between environmental quality and human, animal, and bee health
Exposure to Metalworking Fluid Aerosols and Determinants of Exposure
Metalworking fluid (MWF) aerosols are associated with respiratory disorders including asthma and hypersensitivity pneumonitis. The aims of this study were to describe exposure to inhalable MWF aerosols and volatile compounds in machine shops, to estimate the influence of important determinants of exposure and to compare different sampling techniques for MWF aerosols. Personal full-shift air samples of inhalable aerosol (PAS-6 sampler) and total aerosol (open-faced sampler) were collected on operators in five medium to big-sized machine shops in three companies. The filters were analysed gravimetrically and extracted by supercritical fluid extraction for MWF aerosol and triethanolamine content. In addition, personal measurements were taken for formaldehyde and volatile compounds on adsorbent samplers. Continuous dust measurements were performed with a real-time instrument (DataRAM) during 2 h periods, using 1-min average values. In total, 95 measurements of inhalable aerosol and extracted MWF aerosols on 51 operators were conducted. Within the companies, the average exposure to inhalable aerosol ranged from 0.19 to 0.25 mg m(-3) with geometric standard deviations from 1.56 to 1.79. On average, the extracted fraction of MWF aerosol was 67% of the inhalable aerosol concentration. The exposure levels of triethanolamine, formaldehyde and volatile compounds were generally low. About 45% of the between-worker variance could be explained by use of compressed air, lack of complete enclosure of machines or grinding as cutting task. In 21 workers with continuous aerosol measurements, short-term peak exposures during 6% of the work time contributed to similar to 25% of the average concentration of inhalable MWF aerosol. Inhalable MWF aerosol concentration measured with the PAS-6 sampler was a factor 2 higher than the concentrations derived from the open-faced sampler. These findings suggest that control measures, such as full enclosure of machines and the elimination of the use of compressed air as cleaning technique, are required to reduce the exposure to MWF aerosols to levels below the expected threshold for adverse respiratory health effects
The performance of a natural treatment system for landfill leachate with special emphasis on the fate of organic pollutants
A natural treatment system for the treatment of leachate was Studied at Moskogen landfill in southern Sweden. This facility consists of three consecutive ponds and a soil-plant (SP)system. A test area, receiving water from the third pond with the same hydraulic load as the SP-systern, was Used for estimation of the latter system. Quality parameters including biochemical oxygen demand, total organic carbon, ammonium, nitrate, orthophosphate, and total suspended solids along the treatment line were determined as well as Soluble metals (Cu, Cd, Zn, Cr, Ni, and Pb). In addition a thorough investigation along the treatment tine has also been performed concerning volatile organic Compounds and semi-volatile organic Compounds. Non-polar organic compounds were investigated using gas chromatography-mass spectrometry. Quantification was based on the assumption of equal response for the compounds found in comparison with the chosen marker Substances. For polar, water-soluble Compounds the measurements were restricted to phenolic compounds using high-performance liquid chromatography. Several different types of organic compounds were found in the raw leachate including aromatics, benzene-sulfonamides, biphenyls, naphthalene, organic phosphates, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phenols and phthalates. The treatment system efficiently reduced organic Pollutants, heavy metals, and nitrogen/phosphorous compounds. Most metals and organic compounds in the leachate were already significantly reduced to a low level in the treatment ponds and ammonium-N was efficiently transformed to nitrate-N in the SP-system
Membrane techniques for analysis, sampling and speciation in environmental measurements
Abstract is not availabl