Yangtze Three Gorges Reservoir, China: A holistic assessment of organic pollution, mutagenic effects of sediments and genotoxic impacts on fish

Besides obvious benefits,the Three Gorges Dam's construction resulted in new pollution scenarios with the potentials to threaten the Three Gorges Reservoir(TGR) ecosystem.In order to record organic contamination,to find links to ecotoxicological impacts and to serve as reference for ensuing monitoring,several sites in the TGR area were screened applying the triad approach with additional lines-of-evidence as a holistic assessment method.Sediments and the benthic fish species Pelteobagrus vachellii were sampled in 2011 and 2012 to determine organic pollution levels,mutagenic potentials and genotoxic impacts.Two regional hot-spots near the cities of Chongqing and Kaixian were identified and further investigated in 2013.Only polycyclic aromatic hydrocarbons(PAHs) could be detected in sediments in 2011(165–1653 ng/g),emphasizing their roles as key pollutants of the area.Their ubiquity was confirmed at Chongqing(150–433 ng/g) and Kaixian(127–590 ng/g) in2013.Concentrations were comparable to other major Chinese and German rivers.However,the immense sediment influx suggested a deposition of 216–636 kg PAH/day(0.2–0.6 mg PAH/(m2·day)),indicating an ecotoxicological risk.PAH source analysis highlighted primary impacts of combustion sources on the more industrialized upper TGR section,whereas petrogenic sources dominated the mid-low section.Furthermore,sediment extracts from several sites exhibited significant activities of frameshift promutagens in the Ames fluctuation assay.Additionally,significant genotoxic impairments in erythrocytes of P.vachellii were detected(Chongqing/Kaixian),demonstrating the relevance of genotoxicity as animportant mode of action in the TGR's fish.PAHs,their derivatives and non-target compounds are considered as main causative agents.     

REACh im praxistest

In October 2003, the EU Commission presented the proposal for a new Chemicals Regulation. In late autumn 2005, Parliament and Council were working on finding their position on the Commission’s proposal. From November 2004 to April 2005, a simulation was carried out at EU level aiming to test the workability of registration under REACh. Based on a strategic partnership, the European Chemical Industry Council together with other industry associations, the EU Commission and a number of Member States had launched this project. 53 manufacturers or users of chemicals and competent authorities of 13 EU Member States took part in the simulation: eight registration cases were dealt with in parallel. The participants had to conduct the registration of a substance (including preparatory work) and the dossier evaluation by the authorities. The simulation was performed in a ’free-flow mode’, which means, that the participants worked without any guidance on how to practically implement the duties and tasks as laid down in the draft regulation. In the final phase of the project, the three strategic parners worked towards a common understanding on potential workability problems and suitable options for solutions. This process resulted in a report including a set of agreed recommendations on 12 identified workability issues The recommendations are mostly related to the co-operation between registrants, the sharing of responsibilities and communication between manufactures and down-stream users as well as technical and scientific aspects of dossier compilation., In addition, the recommendations address the need to develop a common understanding across Europe regarding the role of authorities in evaluating the registration dossiers and developing suitable tools for the evaluation. In addition to the set of practical recommendations, SPORT has demonstrated that useful insights in the workability of a new piece of legislation can be gained from simulating the key processes in practise already during the legislative process. Such pilot trials could be seen as a contribution toBetter Regulation, one of the strategic goals of the EU Commission.     

Airborne PCB as a contamination risk on freeze-drying of sediment

In a study of polychlorinated biphenyls (PCB) in freeze-dried sediments from Swedish lakes, the samples were found to contain unexpectedly high concentrations of PCBs. In one of the lakes (Bj?rken), e.g. the concentration of PCB-28 was found to be 189 ng/g dw after freeze-drying compared to 7 ng/g dw after air-drying of the sediment and therefore our hypothesis was that the contamination had occurred during the freeze-drying procedure. Hence, a dry reference sediment (RS) was used in order to identify potential sources of PCB contamination. The investigation included freeze-drying of the dry RS in five different laboratories, exposure to the air in the freeze-drying room, storage at room temperature and air-drying in a certain fume hood and in a laminar flow clean bench. The pattern and concentrations of PCBs detected in the exposed RS were strongly influenced by low chlorinated PCB congeners under all of these conditions with exception for air-drying in the fume hood. Storage in the laboratory air resulted in a slight elevation in the concentrations of low chlorinated PCB congeners, whereas higher concentrations of all PCB congeners were observed after freeze-drying. In all experiments the contamination appeared to be due to adsorption of PCB from the laboratory air. On the basis of these findings we recommend that reference material be subjected to the entire procedure, including sample preparation, in order to monitor contamination and that a procedure involving solvent extraction of wet sediment samples is used, whenever possible, instead of procedures involving dry samples.     

Exposure to airborne isocyanates and other thermal degradation products at polyurethane-processing workplaces

The thermal degradation products of polyurethanes (PURs) and exposure to isocyanates were studied by stationary and personal measurements in five different occupational environments. Isocyanates were collected on glass fibre filters impregnated with 1-(2-methoxyphenyl)piperazine (2MP) and in impingers containing n-dibutylamine (DBA) in toluene. connected to a glass fibre postfilter. The derivatives formed were analysed by liquid chromatography: 2MP derivatives with UV and electrochemical detection and DBA derivatives with mass spectrometric detection. The release of aldehydes and other volatile organic compounds into the air was also studied. In a comparison of the two sampling methods, the 2MP method yielded about 20% lower concentrations for 4,4'-methylenediphenyl diisocyanate (MDI) than did the DBA method. In car repair shops, the median concentration of diisocyanates (given as NCO groups) in the breathing zone was 1.1 microg NCO m(-3) during grinding and 0.3 microg NCO m(-3) during welding, with highest concentrations of 1.7 and 16 pg NCO m(-3), respectively. High concentrations of MDI, up to 25 and 19 microg NCO m(-3), respectively, were also measured in the breathing zone during welding of district heating pipes and turning of a PUR-coated metal cylinder. During installation of PUR-coated floor covering, small amounts of aliphatic diisocyanates were detected in the air. A small-molecular monoisocyanate, methyl isocyanate, and isocyanic acid were detected only during welding and turning operations. The diisocyanate concentrations were in general higher near the emission source than in the workers' breathing zone. A sampling strategy to evaluate the risk of exposure to isocyanates is presented.     

The role of size inequality in self-thinning: A pattern-oriented simulation model for arid savannas

The self-thinning line is a very robust pattern, which can be obtained in modeling studies by a variety of different mechanistic assumptions. Our opinion is that we can only advance in our understanding of mechanisms leading to the self-thinning relationship if we demand that the model also reproduces several other characteristic features (patterns) of the self-thinning process such as the degree of size inequality and the average size. We use a pattern-oriented modeling approach to develop a model of self-thinning under size inequality in overcrowded, even-aged stands, which reproduces these three patterns simultaneously. Our approach is to first develop an initial model based on our current ecological knowledge and then to refine the model by modifying the initial model to derive the model that reproduces all patterns of interest.The initial model is as simple as possible while avoiding incidental, ecologically unjustified, assumptions. It is a further development of zone of influence-simulation models: each plant is described by two circles, one describing a minimum-domain-area and one describing the zone of influence. In the initial model, mortality is “death-by-contact” of minimum-domain-areas and growth is a function of inter-tree competition, i.e. overlapping zones of influence. Model parameterization is based on field data on Acacia reficiens in southern Africa. Simulations follow patches of initially small trees through time for up to 1000 years with five parameters, three describing growth and two describing inter-tree competition. A sensitivity analysis shows that all parameters of the initial model contribute significantly to the number and size of plants through time. The two competition parameters, which describe competitive asymmetry and the size of the zone of influence relative to canopy size, are both important for generating size inequality. Thus, both competitive asymmetry and spatial pattern contribute to size inequality, and their relative importance may vary greatly.The sensitivity analysis suggests that all processes included in the initial model are essential to the evolution of size inequality. However, size inequality under the initial model is below field values, meaning that additional, as yet unconsidered processes, contribute to size inequality. Our best-fit model additionally contains details on growth stochasticity.This study establishes the often-proposed direct link between mortality driven by local competition and self-thinning and highlights the importance of stochasticity in ecological processes.     

Crown condition dynamics of oak in southern Sweden 1988’999

Crown defoliation of oak (Quercus robur and Q. petraea) was analysed in 808 trees during three forest condition surveys (1988, 1993, and 1999) in the southern Sweden. From 1988 to 1999 crown defoliation increased by more than 20%. Changes in crown defoliation were related to the pH in the upper 20–30 cm of the mineral soils, which was closely connected to other measures of soil fertility (cation exchange capacity, CEC and C/N ratio). Trees growing on soils with a high pH (≥4.00, in BaCl₂ filtrate), high CEC and low C/N ratio had significantly lower crown defoliation than trees growing on more acid soils (pH <4.00), indicating that less favourable soil conditions may further enhance oak decline. Age did not differentiate trees with respect to crown defoliation, indicating that decline in crown condition was not due to an age-related increase in crown transparency. Considering only trees younger than 100 years, a significant interaction was observed between changes in crown defoliation and soil pH. Trees younger than 100 years old growing on more acidic soils had a greater increase in crown transparency than trees on more basic soils between 1988 and 1999. Trees ≥100 years old had significantly higher defoliation on more acidic than on more basic soils, however defoliation dynamics of these trees over 1988–99 was not related to soil acidity. Two biotic agents (insect and fungal leaf infections) evaluated in this study did not prove to be important drivers of defoliation dynamics.     

Working conditions in a selected sample of call centre companies in Sweden

BACKGROUND: Call centres (CCs) are among the most rapidly growing forms of workplaces in Sweden. The purpose of the study was to describe and compare working conditions between operators at internal and external CC companies and work tasks of different complexity. METHOD: A questionnaire was answered by 1183 operators, 848 women and 335 men, from 28 different CCs. The questionnaire covered background factors, employment, working hours and remuneration, call logging and monitoring, duties, computer work and workplace design during the previous month. RESULTS: Operators at external companies and operators with low-complexity work tasks were younger, more often employed by the hour and worked on a varying roster. They spent longer time on customer calls and had less varied tasks. Additional remuneration, call logging and monitoring were more common at external companies and among operators with low-complexity work tasks. CONCLUSION: The working conditions varied between internal and external CCs. There was also a variation in working conditions between work tasks of different complexity. There were aspects of supervision style and organization of work at CCs, especially at external ones and those with low-complexity tasks that could introduce stress and lack of well being among the staff.     

Extractable organic matter of Standard Reference Material 1649a influences immunological response induced by pathogen-associated molecular patterns

Background, aim, and scope  

Lungs are permanently and simultaneously challenged by airborne microorganisms and airborne pollutants. Temporal increase of airborne particulate matter (APM), a potential carrier for extractable organic matter (EOM), degrades the situation of pulmonary patients. The Ah receptor (AhR) has been described as an important factor influencing the immunological challenge by viral infections. Molecular mechanisms underlying epidemiological observations are not well understood. Cytokine secretion (IL-6, IL-8, and TGF-β) from human bronchial epithelial cells (Beas2B) was determined as an indicator for immune responses upon co-stimulation with an artificial analog of viral dsRNA [polyinosinic/polycytidylic acid, (PIC)] and EOM of Standard Reference Material 1649a (SRM). Since polycyclic aromatic hydrocarbons are major components of APM usually acting via the AhR, particular focus was on AhR involvement.