Polymers and surfactants on the basis of renewable resources

A new strategy for the preparation of different polymers and special surfactants was developed. First, unsaturated fatty acid methyl esters obtained from plant oils were converted to terminally unsaturated esters and alpha-olefins by metathesis with ethylene using heterogeneous rhenium or homogeneous ruthenium catalysts. These esters were directly copolymerized with ethylene by an insertion-type palladium-catalyzed polymerization to functionalized polyolefins. Polyesters were synthesized by metathetical dimerization of omega-unsaturated esters and subsequent polycondensation of the produced internally unsaturated dicarboxylic esters or by acidic transesterification with petrochemical diols and additional acyclic diene metathesis polymerization. Omega-epoxy fatty acid methyl esters, achieved by a new method of chemo-enzymatic epoxidation, were converted into polyethers with comb-structure catalyzed by aluminoxanes on the one hand and into sugar surfactants by nucleophilic ring-opening with amino carbohydrates on the other hand.     

Pharmazeutisch aktive Substanzen in kleinen Fließgewässern

Background

Current hydrological research is increasingly focusing on pharmaceutically active compounds (PhACs). Concerning the issue of quality of drinking water, this problem has also become the focus of public interest. However, in spire of the fact that the fate of chemicals in surface waters has been assessed in great detail, the influence of groundwater-exchange is yet only little known.

Goal

This study gives emphasis to the question of how transport and degradation of PhACs interact with the exchange of surface water with groundwater. Special interest is given to alternating groundwater regimes.

Methods

Based on a small stream system in the north of Berlin, Germany, a one-dimensional compartment-model was established using differential mass-balance. The stream which, at its mouth, discharges 0.3 m³ s^?1 is already well investigated and thus provides a good empirical data basis. The processes taken into account by the model were ‘exchange of surface-water with groundwater’, ‘decomposition’ as well as ‘transport’ of PhACs. Calculations were performed using the commonly used analgesic Diclofenac as an example and defining 81 scenarios by different groundwater regimes. Hasse Diagramm Technique was used to compare the scenarios.

Results

All scenarios show a big influence of groundwater-exchange to the fate and concentration of PhACs in surface waters. In the case of the modelled stream system, dilution by groundwater was more responsible for a decrease in concentration than degradation was. Furthermore, on the background of a standard scenario, the loss due to groundwater by 5.4 percent was in the same magnitude as the loss due to decomposition (9.7 percent). A crucial difference between punctual versus linear afflux of groundwater has not been observed.

Discussion

The alteration of discharge resulted in a big influence of the case differentiation between ‘constant velocity’ and ‘constant cross-section’. Furthermore, the model was based on the assumption that groundwater was unloaded with PhACs or diluted very well in comparison to the stream. In contrast, regarding measurements in the catchment, groundwater could even be a diffuse source of the contamination of the stream.

Conclusions

The fate of PhACs in our model is crucially driven by interactions with groundwater. Therefore, assessing the risk emanating from substances like Diclofenac, it is very important to regard their accessibility to decomposition as well as the morphology of the stream-system and its interactions with the groundwater.

Perspectives

In this model, the process of transport from the surface to groundwater back to the surface was dealt with insufficiently; in order to be able to observe fully developed interaction in a further step of modelling, a groundwater-transportmodel should be coupled completely with a surface-water-model.     

Occurrence of organochlorine pesticides in indoor dust

Organochlorine pesticides are present in the environment and suspected of causing serious health effects. Diet has been the main exposure source, but indoor source release is gaining focus. Within a monitoring study of polychlorinated biphenyls of Danish buildings built during the 1960s and 1970s, we coincidently determined extreme levels of dichlorodiphenyltrichloroethane (DDT) levels in two of ten random samples. This raises concern and further large scale investigations are warranted to confirm this.     

Fungal DNA and pet allergen levels in Swedish day care centers and associations with building characteristics

Pet allergens and mold growth related to damp are common phenomena in day care centers in Sweden but exposure measurements of these factors are lacking. The aim of this study was to investigate the relationship between building construction and indoor environment quality in Swedish day care centers and the potential for exposure to fungi (analyzed by quantitative PCR) and animal allergens (analyzed by ELISA). Measurements were performed in 21 day care centers (103 rooms) from one municipality in Sweden, which were identified as constructions at risk of dampness (85% of the buildings) and with visible damage and mold growth (54% of the buildings). Dust samples were collected using cotton swab and Petri dishes. Total fungal DNA was detected in 99% and 100%, Aspergillus/Penicillium DNA in 54% and 68%, and Stachybotrys chartarum DNA in 4% and 9% of the investigated rooms in cotton swab and Petri dish samples, respectively. The total fungal DNA levels (Geometric Mean, GM) were 4.2 × 10(6) cell equivalents per m(2) and 2.9 × 10(5) cell equivalents per m(2) per day in the swab and Petri dish samples, respectively. The concentrations (GM) of cat (Fel d1), dog (Can f1), and horse (Equ cx) allergens were 9.4, 7.2 ng m(-2) day(-1), and 5.0 unit per m(2) per day, respectively. Total fungal DNA levels were higher in risk construction buildings (p = 0.01), in rooms with linoleum flooring material (p = 0.003), and in buildings with rotating heat exchangers (p = 0.02). There were associations between total fungal DNA levels and cat (p = 0.02), dog (p < 0.001), and horse (p = 0.001) allergens. In conclusion, risk constructions, damp constructions, mould growth, fungal DNA, and animal allergens were common exposure factors in Swedish day care centers. Building constructions that represent a high risk for internal dampness should be avoided in the future, and measures to reduce allergen levels should be considered to protect pet-allergic children from asthmatic problems.     

Self-Rated Physical Loads of Work Tasks Among Firefighters

Objectives. The present study sought to identify firefighters’ rated physical demands for the most frequently occurring work tasks and to determine if the ratings differed between full-time and part-time firefighters to help create a basis for the development of physical employment tests for firefighters. Methods. An extensive questionnaire was completed by 125 and 68 firefighters in 2000 and 2010, respectively. The data were analysed with the Mann-Whitney U test and binominal test and ranked on the basis of the responses in each category. Results. Significant differences were seen between the full- and part-time firefighters. The work tasks rated as the most physically strenuous in terms of aerobic fitness, muscle strength, work posture and body control by most respondents were smoke diving upstairs (carrying a hose), victim rescue in different ways, carrying a stretcher over terrain and pulling a hose. Conclusions. Physically strenuous work tasks should be included in the end-point performance variables used to select physical performance tests for firefighters. The part-time firefighters with no experience in several of the work tasks suggests that work-related exercises are important if both groups of firefighters are expected to do similar work.     

Heat Gain From Thermal Radiation Through Protective Clothing With Different Insulation,Reflectivity and Vapour Permeability

The heat transferred through protective clothing under long wave radiation compared to a reference condition without radiant stress was determined in thermal manikin experiments. The influence of clothing insulation and reflectivity, and the interaction with wind and wet underclothing were considered. Garments with different outer materials and colours and additionally an aluminised reflective suit were combined with different number and types of dry and pre-wetted underwear layers. Under radiant stress, whole body heat loss decreased, i.e., heat gain occurred compared to the reference. This heat gain increased with radiation intensity, and decreased with air velocity and clothing insulation. Except for the reflective outer layer that showed only minimal heat gain over the whole range of radiation intensities, the influence of the outer garments’ material and colour was small with dry clothing. Wetting the underclothing for simulating sweat accumulation, however, caused differing effects with higher heat gain in less permeable garments.