Evaluation of two adsorbents for diffusive sampling and thermal desorption-gas chromatographic analysis of monoterpenes in air

Tube type samplers with two different adsorbents, Chromosorb 106 and Tenax TA, were evaluated by laboratory experiments and field tests for simultaneous diffusive sampling of alpha-pinene, beta-pinene and delta 3-carene and subsequent thermal desorption-gas chromatographic analysis. No statistically significant effects of exposure time, concentrations of monoterpenes or relative humidity were found for samplers with Chromosorb 106 when running a factorial design, with the exception of the adsorption of delta 3-carene, for which some weak effects were noted. Samplers with Tenax TA were affected by the sampling time as well as the concentration for all terpenes, with a strong interaction effect between these two factors. The terpenes showed good storage stability on both adsorbents. No effect of back-diffusion was noted when using Chromosorb 106, while Tenax TA showed some back-diffusion effects. The uptake rates, in ml min-1, for the terpenes on Chromosorb 106 were 0.36 for alpha-pinene, 0.36 for beta-pinene and 0.40 for delta 3-carene. The corresponding average values on Tenax TA were 0.30 for alpha-pinene, 0.32 for beta-pinene and 0.38 for delta 3-carene. The field validation proved that diffusive sampling on Chromosorb 106 agreed well with pumped sampling on charcoal for stationary samples, while the personal samples indicated a discrepancy of 25% between Chromosorb 106 and charcoal samples. Tenax TA generally gave lower results than Chromosorb 106 in all field samples. Samplers packed with Chromosorb 106 could be used to monitor terpene levels in workplaces such as sawmills. The major advantages with this method are the sampling procedure, which is simple to perform compared to other techniques, the easily automated analysis procedure and the possibility to reuse the samplers.     

麦夸里岛毛皮海豹体内小塑料颗粒的来源和生物聚集

本文研究了从麦夸里岛上毛皮海豹(Arctocephalus spp.)粪便中发现的164个塑料颗粒(平均长度为4.1mm).其中41个塑料颗粒的电子显微照片显示,从其形状来看,没有一个可被确定为塑料颗柱原料--通常这样的颗粒是圆柱形和球形的.而海豹粪便中的164个塑料颗粒全都是7种颜色的角形颗粒(原料颗粒通常是透明的或白色的),并可被分为两类①沿晶体线碎裂的和可能是紫外线分解的;②被磨蚀成带有圆角的不规则形状(擦痕明显可见).白色、棕色、绿色、黄色以及蓝色是最常见的颜色.在成分上,它们来自于5种聚合物群聚乙烯93%;聚丙烯4%;多(1-CI-1-聚丁二烯)聚氯丁二烯2%;三聚氰胺-尿素(酚)(甲醛)树脂0.5%以及纤维素(绳纤维)0.5%.较大的群是漂浮的,比重小于海水.这些小塑料是由较大颗粒(碎片)分解而成的.它们看来是被水冲上岸的并在卵石海滩上受到研磨的塑料用品分解而成的.大多数颗粒(70%)肯定是由于经过不断的磨蚀而最后形成今天的形状.据假设,塑料颗粒被冲到海洋中,然后按其大小有选择地被一种中上层鱼--Electrona subaspera--吃掉,而这种鱼后来又被毛皮海豹吃掉.因此,这些塑料颗粒是由这种鱼和海豹在其正常的摄食过程中聚集的.     

Contribution of precursor compounds to the release of per- and polyfluoroalkyl substances (PFASs) from waste water treatment plants (WWTPs)

Per-and polyfluoroalkyl substances(PFASs) are ubiquitous in sludge and water from waste water treatment plants, as a result of their incorporation in everyday products and industrial processes. In this study, we measured several classes of persistent PFASs,precursors, transformation intermediates, and newly identified PFASs in influent and effluent sewage water and sludge from three municipal waste water treatment plants in Sweden, sampled in 2015. For sludge, samples from 2012 and 2014 were analyzed as well.Levels of precursors in sludge exceeded those of perfluoroalkyl acids and sulfonic acids(PFCAs and PFSAs), in 2015 the sum of polyfluoroalkyl phosphoric acid esters(PAPs) were 15–20 ng/g dry weight, the sum of fluorotelomer sulfonic acids(FTSAs) was 0.8–1.3 ng/g,and the sum of perfluorooctane sulfonamides and ethanols ranged from non-detected to 3.2 ng/g. Persistent PFSAs and PFCAs were detected at 1.9–3.9 ng/g and 2.4–7.3 ng/g dry weight, respectively. The influence of precursor compounds was further demonstrated by an observed substantial increase for a majority of the persistent PFCAs and PFSAs in water after waste water treatment. Perfluorohexanoic acid(PFHxA), perfluorooctanoic acid(PFOA), perfluorohexane sulfonic acid(PFHxS), and perfluorooctane sulfonic acid(PFOS)had a net mass increase in all WWTPs, with mean values of 83%, 28%, 37% and 58%,respectively. The load of precursors and intermediates in influent water and sludge combined with net mass increase support the hypothesis that degradation of precursor compounds is a significant contributor to PFAS contamination in the environment.     

Models for waste life cycle assessment: Review of technical assumptions

A number of waste life cycle assessment (LCA) models have been gradually developed since the early 1990s, in a number of countries, usually independently from each other. Large discrepancies in results have been observed among different waste LCA models, although it has also been shown that results from different LCA studies can be consistent. This paper is an attempt to identify, review and analyse methodologies and technical assumptions used in various parts of selected waste LCA models. Several criteria were identified, which could have significant impacts on the results, such as the functional unit, system boundaries, waste composition and energy modelling. The modelling assumptions of waste management processes, ranging from collection, transportation, intermediate facilities, recycling, thermal treatment, biological treatment, and landfilling, are obviously critical when comparing waste LCA models.This review infers that some of the differences in waste LCA models are inherent to the time they were developed. It is expected that models developed later, benefit from past modelling assumptions and knowledge and issues. Models developed in different countries furthermore rely on geographic specificities that have an impact on the results of waste LCA models. The review concludes that more effort should be employed to harmonise and validate non-geographic assumptions to strengthen waste LCA modelling.     

Investigating biodiversity trajectories using scenarios – Lessons from two contrasting agricultural landscapes

Agriculture is the major land use at a global scale. In addition to food production, multifunctionality of landscapes, including values and ecosystem services like biodiversity, recreation and culture, is now focus for management. This study explores how a scenario approach, involving different stakeholders, may help to improve landscape management for biodiversity conservation. Local farmers and executives at the County Administrative Board were invited to discuss rural development and conditions for farmland biodiversity in two Swedish landscapes. The potential biodiversity for three future land use scenarios for the two landscapes was discussed: nature conservation, outdoor recreation and energy production, and compared with current and historical landscapes in each region.Analyses of habitat areas, connectedness and landscape diversity suggested that the energy and recreation scenarios had a negative impact on farmland biodiversity, whereas the nature conservation scenario, the current and historically reconstructed landscapes had a higher potential for biodiversity. The farmers appreciated the nature conservation scenario, but also the energy production scenario and they highlighted the need of increased subsidies for management of biodiversity. The farmers in the high production area were less interested in nature quality per se. The executives had similar opinions as the farmers, but disagreed on the advantages with energy production, as this would be in conflict with the high biodiversity and recreational values. The local physical and socio-economical conditions differ between landscapes and potentially shaped the stakeholders emotional attachment to the local environment, their opinions and decisions on how to manage the land. We stress the importance of incorporating local knowledge, visions and regional prerequisites for different land uses in conservation, since site and landscape specific planning for biodiversity together with a flexible subsidy system are necessary to reach the conservation goals within EU.     

Biotic habitat complexity controls species diversity and nutrient effects on net biomass production

Canopy-forming plants and algae commonly contribute to spatial variation in habitat complexity for associated organisms and thereby create a biotic patchiness of communities. In this study, we tested for interaction effects between biotic habitat complexity and resource availability on net biomass production and species diversity of understory macroalgae by factorial field manipulations of light, nutrients, and algal canopy cover in a subtidal rocky-shore community. Presence of algal canopy cover and/or artificial shadings limited net biomass production and facilitated species diversity. Artificial shadings reduced light to levels similar to those under canopy cover, and net biomass production was significantly and positively correlated to light availability. Considering the comparable and dependent experimental effects from shadings and canopy cover, the results strongly suggest that canopy cover controlled net biomass production and species diversity by limiting light and thereby limiting resource availability for community production. Canopy cover also controlled experimental nutrient effects by preventing a significant increase in net biomass production from nutrient enrichment recorded in ambient light (no shading). Changes in species diversity were mediated by changes in species dominance patterns and species evenness, where canopy cover and shadings facilitated slow-growing crust-forming species and suppressed spatial dominance by Fucus vesiculosus, which was the main contributor to net production of algal biomass. The demonstrated impacts of biotic habitat complexity on biomass production and local diversity contribute significantly to understanding the importance of functionally important species and biodiversity for ecosystem processes. In particular, this study demonstrates how loss of a dominant species and decreased habitat complexity change the response of the remaining assembly to resource loading. This is of potential significance for marine conservation since resource loading often promotes low habitat complexity and canopy species are among the first groups lost in degraded aquatic systems.     

Methods for synthesis of nonabromodiphenyl ethers and a chloro-nonabromodiphenyl ether

Polybrominated diphenyl ethers (PBDEs) have been used extensively as brominated flame retardants (BFRs) in textiles, upholstery and electronics. They are ubiquitous contaminants in wildlife and humans. A low concentration of nonabrominated diphenyl ethers (nonaBDEs) is present in commercial DecaBDE and they are also abiotic and biotic debromination products of decabromodiphenyl ether (BDE-209). The objective of the present work was to develop methods for synthesis of the three nonaBDEs, 2,2',3,3',4,4',5,5',6-nonabromodiphenyl ether (BDE-206), 2,2',3,3',4,4',5,6,6'-nonabromodiphenyl ether (BDE-207) and 2,2',3,3',4,5,5',6,6'-nonabromodiphenyl ether (BDE-208), with the intention of making them available as authentic standards for analytical, toxicological and stability studies, as well as studies regarding physical-chemical properties. Two methods were developed, one based on perbromination of phenoxyanilines and the other via reductive debromination of BDE-209 by sodium borohydride followed by chromatographic separation of the three nonaBDE isomers formed. An additional nonabrominated compound, 4'-chloro-2,2',3,3',4,5,5',6,6'-nonabromodiphenyl ether (Cl-BDE-208), was also synthesized in the present work. Cl-BDE-208, prepared by the perbromination of 4-chlorodiphenyl ether, may be used as an internal standard in analysis of highly brominated diphenyl ethers. BDE-206, BDE-207, BDE-208 and Cl-BDE-208 were characterized by 1H NMR, 13C NMR, electron ionization mass spectra and by their melting points. The structures of all three nonaBDEs have been characterized previously by X-ray crystallography.     

Male bird song attracts females — a field experiment

Summary The initial stage of pair formation of the pied and the collared flycatcher (Ficedula hypoleuca and F. albicollis) was simulated in a field experiment. Male dummies positioned near nest boxes and singing by means of tape-recorded song from loudspeakers offered prospecting females a nest box combined with an automatic trap. An unequivocal demonstration of female arrival at the male's territory was obtained by the trapping of the female. Control nest-box traps were provided with silent dummies. Factors other than male song causing female attraction were controlled by a daily switch of the position of singing and silent dummies. Nine out of ten females were caught in nest-box traps with singing dummies (one-tailed binomial test, P=0.011). The result supports the hypothesis that male song functions in mate attraction. This hypothesis has never previously been tested in field experiments although circumstantial evidence for it has been available.     

Behaviour and tolerance to hypoxia in juvenile Norway lobster (Nephrops norvegicus ) of different ages

The annual occurrence of hypoxia (<25% oxygen saturation) in the bottom waters along the Swedish west coast coincides with the postlarval settlement of Norway lobster, Nephrops norvegicus (L.). This study investigates behaviour and the experimental effects of low oxygen concentrations in juvenile N. norvegicus of different ages. All experimental individuals were reared to the juvenile (postlarval) stage in the laboratory and then given sediment as a substratum. Behavioural responses to low oxygen concentrations were tested in early and late Postlarvae 1 exposed to normoxia (>80% oxygen saturation, pO₂ > 16.7 kPa), moderate hypoxia (30% oxygen saturation, pO₂ = 6.3 kPa) and hypoxia (25% oxygen saturation, pO₂ = 5.2 kPa). The experiments were run for a maximum period of 24 h or until individuals died. Behaviour was studied using sequential video recordings of four behavioural activities: digging, walking, inactivity or flight (escape swimming up into the water column). Behaviour and mortality changed with lowered oxygen concentrations; energetically costly activities (such as walking) were reduced, and activity in general declined. In normoxia, juveniles initially walked and then burrowed, but when exposed to hypoxia they were mainly inactive with occasional outbursts of escape swimming. To increase oxygen availability the juveniles were observed to raise their bodies on stilted legs (similar to adults in hypoxic conditions), but oxygen saturations of 25% were lethal within 24 h. The results suggest that the main gas exchanges of early postlarval stages occur over the general body surface. Burrowing behaviour was tested in Postlarvae 1 and 2 of different ages held in >80% oxygen saturation for 1 wk. The difference in time taken to complete a V-shaped depression or a U-shaped burrow was measured. The results showed a strong negative relationship between postlarval age and burrowing time, but all individuals made a burrow. Juveniles were more sensitive to hypoxia than adults. Thus, the possible consequences of episodic hypoxia for the recruitment of Nephrops norvegicus and for the recolonization of severely affected areas are discussed. Received: 4 August 1996 / Accepted: 11 October 1996