Estadísticas de uso de Z39.50

Sección: La RedHa transcurrido un año desde que se realizó la primera sesión informativa sobre Z39.50 dirigida a las bibliotecas de Madrid. En febrero de 2002 se repitieron estas jornadas de formación en Valencia y Barcelona, y en junio en AndalucíaN

Occurrence and temporal variations of TMDD in the river Rhine, Germany

Background, aim, and scope: The chemical substance 2,4,7,9-tetramethyl-5-decyne-4,7-diol (TMDD) is a non-ionic surfactant used as an industrial defoaming agent and in various other applications. Its commercial name is Surynol 104® and the related ethoxylates are also available as Surfynol® 420, 440, 465 and 485 which are characterized by different grades of ethoxylation of TMDD at both hydroxyl functional groups. TMDD and its ethoxylates offer several advantages in waterborne industrial applications in coatings, inks, adhesives as well as in paper industries. TMDD and its ethoxylates can be expected to reach the aquatic environment due its widespread use and its physico-chemical properties. TMDD has previously been detected in several rivers of Germany with concentrations up to 2.5 µg/L. In the United States, TMDD was also detected in drinking water. However, detailed studies about its presence and distribution in the aquatic environment have not been carried out so far. The aim of the present study was the analysis of the spatial and temporal concentration variations of TMDD in the river Rhine at the Rheingütestation Worms (443.3 km). Moreover, the transported load in the Rhine was investigated during two entire days and 7 weeks between November 2007 and January 2008. Materials and methods: The sampling was carried out at three different sampling points across the river. Sampling point MWL1 is located in the left part of the river, MWL2 in the middle part, and MWL4 in the right part. One more sampling site (MWL3) was run by the monitoring station until the end of 2006, but was put out of service due to financial constrains. The water at the left side of the river Rhine (MWL1) is influenced by sewage from a big chemical plant in Ludwigshafen and by the sewage water from this city. The water at the right side of the river Rhine (MWL4) is largely composed of the water inflow from river Neckar, discharging into Rhine 14.9 km upstream from the sampling point and of communal and industrial wastewater from the city Mannheim. The water from the middle of the river (MWL2) is largely composed of water from the upper Rhine. Water samples were collected in 1-L bottles by an automatic sampler. The water samples were concentrated by use of solid-phase extraction (SPE) using Bond Elut PPL cartridges and quantified by use of gas chromatography-mass spectrometry (GC-MS). The quantification was carried out with the internal standard method. Based on these results, concentration variations were determined for the day profiles and week profiles. The total number of analyzed samples was 219. Results: The results of this study provide information on the temporal concentration variability of TMDD in river Rhine in a cross section at one particular sampling point (443.3 km). TMDD was detected in all analyzed water samples at high concentrations. The mean concentrations during the 2 days were 314 ng/L in MWL1, 246 ng/L in MWL2, and 286 ng/L in MWL4. The variation of concentrations was low in the day profiles. In the week profiles, a trend of increasing TMDD concentrations was detected particularly in January 2008, when TMDD concentrations reached values up to 1,330 ng/L in MWL1. The mean TMDD concentrations during the week profiles were 540 ng/L in MWL1, 484 ng/L in MWL2, and 576 ng/L in MWL4. The loads of TMDD were also determined and revealed to be comparable in all three sections of the river. The chemical plant located at the left side of the Rhine is not contributing additional TMDD to the river. The load of TMDD has been determined to be 62.8 kg/d on average during the entire period. By extrapolation of data obtained from seven week profiles the annual load was calculated to 23 t/a. Discussion: The permanent high TMDD concentrations during the investigation period indicate an almost constant discharge of TMDD into the river. This observation argues for effluents of municipal wastewater treatment plants as the most likely source of TMDD in the river. Another possible source might be the degradation of ethoxylates of TMDD (Surfynol® series 400), in the WWTPs under formation of TMDD followed by discharge into the river. TMDD has to be considered as a high-production-volume (HPV) chemical based on the high concentrations found in this study. In the United States, TMDD is already in the list of HPV chemicals from the Environmental Protection Agency (EPA). However, the amount of TMDD production in Europe is unknown so far and also the biodegradation rates of TMDD in WWTPs have not been investigated. Conclusions: TMDD was found in high concentrations during the entire sampling period in the Rhine river at the three sampling points. During the sampling period, TMDD concentrations remained constant in each part of the river. These results show that TMDD is uniformly distributed in the water collected at three sampling points located across the river. ‘Waves’ of exceptionally high concentrations of TMDD could not be detected during the sampling period. These results indicate that the effluents of WWTPs have to be considered as the most important sources of TMDD in river Rhine. Recommendations and perspectives: Based also on the occurrence of TMDD in different surface waters of Germany with concentrations up to 2,500 ng/L and its presence in drinking water in the USA, more detailed investigations regarding its sources and distribution in the aquatic environment are required. Moreover, the knowledge with respect to its ecotoxicity and its biodegradation pathway is scarce and has to be gained in more detail. Further research is necessary to investigate the rate of elimination of TMDD in municipal and industrial wastewater treatment plants in order to clarify the degradation rate of TMDD and to determine to which extent effluents of WWTPs contribute to the input of TMDD into surface waters. Supplementary studies are needed to clarify whether the ethoxylates of TMDD (known as Surfynol 400® series) are hydrolyzed in the aquatic environment resulting in formation of TMDD similar to the well known cleavage of nonylphenol ethoxylates into nonylphenols. The stability of TMDD under anaerobic conditions in groundwater is also unknown and should be studied

Substitution potential of bio-based packaging films in food industries

Hemizellulose basierte Verpackungsfolien (HBF) können unter anderem als Lebensmittelverpackung eingesetzt werden. Auf Basis einer B2B-Befragung wurde ein Substitutionsmodel unter Berücksichtigung der technischen Eigenschaften entwickelt. Demnach kommen bestehende HBF auf ein Potenzial von rund 927 t/a oder 0,1% der eingesetzten Menge im deutschsprachigen Raum. Die hohe Wasserdampfdurchlässigkeit und die mangelnde Siegelbarkeit sind dabei die limitierenden Faktoren.Hemicelluloses based films (HBF) may be used for food packaging. Based on information from a B2B-survey in the food packaging industry in German speaking countries, a substitution potential model considering varying film properties was developed. State of the art HBF show therefore a potential of 927 t/a or 0.1% of the total volume. The high water vapor permeability and the lack of sealing capabilities are considered major limitations.Caroline Ledl, Philipp Stary, Peter Schwarzbauer und Tobias Ster

Strategic decisions on knowledge development and diffusion at pilot and demonstration projects: An empirical mapping of actors, projects and strategies in the case of circular forest bioeconomy

The knowledge developed at pilot and demonstration projects (PDPs) plays an essential role for emerging biorefinery technologies. This research addresses the unexplored role of actor strategies in the construction and operation of PDPs. Drawing on the theory of technological innovation systems, we conduct a pan-European survey to map the current pilot and demonstration projects, their actors and strategies. An online survey has been carried out among managers of PDPs to explore the strategic decisions to develop and diffuse knowledge. The findings reveal that the knowledge developed at PDPs and diffused in PDP contexts tends to focus on the development of technological knowledge at lower stages of technological maturity, while activities related to non-technological knowledge and system build-up were given less importance. Overall, our findings indicate that the consideration of actor strategies is of central importance to explain the value of the knowledge developed in PDP contexts for the transition to a circular forest bioeconomy

The Role of the Social Licence to Operate in the Emerging Bioeconomy—A Case Study of Short-Rotation Coppice Poplar in Slovakia

Wood plays a key role in the endeavours of the EU to establish a circular bioeconomy based on renewable biological resources. Today, forestry on its own cannot sustainably satisfy the demand for woody biomass. Short-Rotation Coppice (SRC) represents a possible alternative production system where fast-growing tree species are cultivated on agricultural land. Thus far, lacking engagement from farmers and public opposition against other bioenergy projects have hindered the expansion of SRC. At the same time, society does not consider wood unconditionally sustainable anymore. The Social License to Operate (SLO) describes the dynamic relationship between industries, their communities, and other stakeholders. The present study adapted a quantitative SLO model based on integrative socio-psychological relationship modelling and applied it to a case study in Slovakia. The roles of trust, fairness, impact assessment, and governance hold for the establishment of social acceptance were analysed with Structural Equation Modelling (SEM). The model revealed the perception of individual benefits as the strongest predictor for social acceptance. The average level of social acceptance was found to be between “Acceptance” and “Approval”. The results thus show that SRC currently must not face societal pressure in Slovakia. However, the SLO is not static and must be constantly re-evaluated

The Role of the Social Licence to Operate in the Emerging Bioeconomy—A Case Study of Short-Rotation Coppice Poplar in Slovakia

Wood plays a key role in the endeavours of the EU to establish a circular bioeconomy based on renewable biological resources. Today, forestry on its own cannot sustainably satisfy the demand for woody biomass. Short-Rotation Coppice (SRC) represents a possible alternative production system where fast-growing tree species are cultivated on agricultural land. Thus far, lacking engagement from farmers and public opposition against other bioenergy projects have hindered the expansion of SRC. At the same time, society does not consider wood unconditionally sustainable anymore. The Social License to Operate (SLO) describes the dynamic relationship between industries, their communities, and other stakeholders. The present study adapted a quantitative SLO model based on integrative socio-psychological relationship modelling and applied it to a case study in Slovakia. The roles of trust, fairness, impact assessment, and governance hold for the establishment of social acceptance were analysed with Structural Equation Modelling (SEM). The model revealed the perception of individual benefits as the strongest predictor for social acceptance. The average level of social acceptance was found to be between “Acceptance” and “Approval”. The results thus show that SRC currently must not face societal pressure in Slovakia. However, the SLO is not static and must be constantly re-evaluated