Myeloperoxidase-catalyzed formation of PCDD/F from chlorophenols

Chlorophenols (CP) are transformed in vitro to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) by a biochemical-catalyzed oxidation. This is shown for 2,4,5-tri-, 2,3,4,6-tetra-and pentachlorophenol with myeloperoxidase recovered from human leucocytes in the presence of hydrogen peroxide. The yield, the reaction, and the PCDD/F-pattern found depend on the CP. The formation rates are in the micromol-per-mol range for all substrates. The experiments confirm the suspicion that a biochemical formation of PCDD/F from precursors such as CPs can take place in the human body and that this metabolic pathway may lead to a higher inner exposure with PCDD/F than is now assumed.     

Place Attachment,Climate Friendly Behavior,and Support for Climate Friendly Management Action among State Park Visitors

This study examined the role of place attachment in determining visitors’ willingness to engage in climate friendly behavior in parks and support for management actions to minimize climate-change impacts. The sample consisted of visitors to Missouri State Parks (n = 1775). Place attachment was measured using 12 items of place identity, place dependence, and social bonding. Exploratory factor analysis of climate friendly behavior items revealed two dimensions: Visit based (i.e., short-term, immediate actions individuals could take during their visit) and Big Picture (i.e., advocacy actions that suggest a long-term engagement with parks). A path analysis demonstrated that the dimensions of place attachment predict climate friendly behavior and support for climate friendly management action in different ways. Specifically, place identity increased climate friendly behavior (big picture) and place dependence increased both climate friendly behavior (visit based) and support for climate friendly management action. Findings from this study provided evidence for the importance of place attachment as a means for engaging visitors in climate-related actions both in and beyond the park setting.     

Treatment of the methanogenic landfill leachate with thin open channel reverse osmosis membrane modules

A leachate purification system, equipped with the thin open channel spiral wound modules, is studied in this paper. In Phase I, effluent from an activated sludge process followed by the flocculation/sedimentation process was fed into the landfill leachate treatment unit. After 2 wk of operation, the permeate flux dropped dramatically, from an average value of 6.5l/m(2)/h to 4.23 l/m(2)/h. The significant decline of membrane flux was likely caused by membrane fouling. In Phase II, raw leachate was fed directly into the reverse osmosis leachate treatment system. An average flux of 7.8l/m(2)/h was maintained at an initial trans-membrane pressure difference of 20 bar, which increased to 40 bar before membrane chemical cleaning. An average recovery rate of 70% was achieved. Throughout the observation in Phase II, an average reduction rate of 98.2% for the dissolved solids was obtained. The reduction rate of COD was greater than 99.5% with a constant level of the permeate COD. Chloride was eliminated by more than 99%, while over 98% of NH(4)-N was reduced. A negligible permeate flux drop was observed after cleaning the membrane effectively. The study shows that direct reverse osmosis membrane filtration with thin open channel spiral wound modules is able to achieve satisfactory results in terms of water quality, process stability and membrane flux. The obtained quality of the permeate quality in this study met the German standards for leachate discharge. At the end of each filtration cycle, the membrane was maintained through alkaline chemical cleaning in order to remove any irreversible membrane fouling. After the maintenance procedure, the membrane flux was found to recover to the initial value.     

Economic assessment of microbial biodiesel production using heterotrophic yeasts

The production of biodiesel using oleaginous microorganisms is investigated as promising alternative to produce a truly sustainable and renewable transportation fuel. While the feasibility of this approach has been shown on the laboratory scale, a commercial scale implementation is to date inhibited due to economic restraints. In order to evaluate the current cost situation and to develop suggestions to reduce production related costs, a simple cost analysis of the proposed microbial oil production process has been carried out. For closed fermentation in large-scale fermenters a break-even price of 2,350 US$ t^–1 for microbial oil was calculated. In the context of a sensitivity analysis it was shown that especially alterations in capital cost can lead to overall cost reductions. Accordingly, an open pond cultivation approach was designed, cutting the cost for equipment almost in half and decreasing the break-even price to 1,723 US$ t^–1. However, these reductions are only feasible when stable biomass and lipid yields can be ensured in open-pond systems, because the sensitivity analysis identified these yield parameters as leading factors influencing the break-even price. Even under very optimistic assumptions, it was not possible to reduce the break-even price below that of conventional plant oils as competitive products. Therefore, economic feasibility of the process will probably only occur if on one hand considerable technical development and efficiency improvements of the production process are made while on the other hand plant and crude oil prices are continuously increasing.     

Persistent organic pollutants (POP) in a benthic omnivore--a comparison between lake and stream crayfish populations

We investigated the accumulation of PCB and DDT in crayfish populations in 10 streams in southern Sweden. The results were compared with an earlier study on crayfish in lakes from the same area. We found that the concentration of pollutants in crayfish did not differ between the two types of systems. Variation in body burden was higher in stream living crayfish probably because of the higher influence from pollutants deposited in the catchment area and the more dynamic transport in streams. In streams, p,p'-DDE concentrations were positively correlated to trophic status (total phosphorous) while PCB did not show any correlation with the nutrient regime. Further, mean SigmaPCB and p,p'-DDE concentrations in crayfish did not correlate in streams. We suggest that the sources of the two pollutants differ for stream living crayfish. The results indicate that crayfish in streams are affected to a higher degree to pollutants in the catchment area and the precipitation regime. In lakes, internal processes govern uptake of pollutants in crayfish.     

Monitoring terbutryn pollution in small rivers of Hesse, Germany

Four small river systems in Hesse, Germany, were investigated with respect to seasonal and spatial concentrations of the herbicide terbutryn [2-(t-butylamino)-4-(ethylamino)-6-(methylthio)-s-triazine]. Despite introduction of a ban on its use as a herbicide in July 2003, terbutryn was still present in the rivers during the whole sampling period from September 2003 to September 2006, and there was no trend of decreasing concentration during this time. In the Weschnitz and Modau river systems the mean terbutryn concentration exceeded the German drinking water ordinance threshold value for single biocides. Maximum concentrations of up to 5.6 microg l(-1) were determined in the Weschnitz River. Higher terbutryn concentrations in summer are suggested to originate from agricultural sources, as well as from sediment redissolution. Effluents of two sewage treatment plants had high terbutryn concentrations, indicating that terbutryn enters the rivers from this source. Sources other than agriculture must explain terbutryn occurrence in the rivers during winter, when farm pesticide application typically ceases. The potential for mobilization of terbutryn from sediments and leaching from soils are discussed.     

An economic and environmental assessment of carbon capture and storage (CCS) power plants: a case study for the City of Kiel

In the not too distant future several power plants throughout Europe will have to be replaced and the decision has to be made whether to build coal-fired power plants with carbon capture and storage (CCS). In a study for the city of Kiel in northern Germany only an 800 MW coal power plant reaches a required minimum for rentability. This study looks at an additional economic and environmental evaluation of a coal plant with CCS. We find that in two out of three carbon and energy price scenarios integrated gasification combined cycle (IGCC) plants with CCS have the greatest rentability. Pulverised coal (PC) plants with CCS can only compete with other options under very favourable assumptions. Life-cycle emissions from CCS are less than 70% of a coal plant – compared with at least more than 80% when only considering direct emissions from plants. However, life-cycle emissions are lower than in any other assessed option.     

Salps in the Lazarev Sea,Southern Ocean: I. Feeding dynamics

Feeding dynamics of the Antarctic salps Ihlea racovitzai and Salpa thompsoni were studied in the Lazarev Sea in fall 2004, summer 2005–2006 and winter 2006. Pigment concentrations in the guts of both species were positively correlated with ambient surface chlorophyll a (chl a). No evidence was found for salp clogging even at dense surface concentrations of up to 7 μg chl a L⁻¹. However, gut pigment concentrations had a lower range than ambient pigment concentrations, suggesting that salps increased retention times of ingested material in low-food environments. For medium-sized I. racovitzai and S. thompsoni, estimated individual daily rations reached 7–10 and >100% of body carbon in winter and summer, respectively. Daily respiratory needs of I. racovitzai and S. thompsoni accounted for 28 and 22% of daily carbon assimilation based on pigment ingestion rates in winter, and for 2 and 1% in summer, respectively. The grazing impact of the salp populations on the phytoplankton standing stock was negligible during all seasons due to generally low salp densities. Fatty acid trophic biomarkers in the salps suggest high year-round contributions of flagellates and modest contributions of diatoms to the salp’s diet. These markers showed low seasonal variability for I. racovitzai. The more pronounced seasonality of trophic markers in S. thompsoni were likely related to their generally deeper residence depth in winter linked to a seasonal alternation of sexual and asexual generations.     

Age-related multi-year associations in female humpback whales (Megaptera novaeangliae)

Analyses of social structures in baleen whales are rare, and so far, they are thought to consist of mostly short and unstable associations. We investigated the association patterns of individual humpback whales from a summer feeding aggregation in the Gulf of St. Lawrence from 1997 to 2005. Photo-identified animals were sexed using genetic methods and were grouped into five categories: juvenile males/females, mature males and lactating/non-lactating females. We calculated half-weight association indices within and between the groups and found that 45% of the observation showed single animals and another 45% small groups (two to three) consisting mainly of mature animals besides lactating females. Using permutation tests, we found evidence for long-term associations between mature males and non-lactating females as well as among non-lactating females. Standardised lagged association rates revealed that these male–female groups disassociated quickly over about 2 weeks, whereas associations increased again towards the beginning of the breeding season. Non-lactating females of similar age engaged in multi-seasonal stable pairs for up to six consecutive feeding seasons; no mature male–female association was observed in consecutive years. The females with the most stable and long-term associations also had the highest reproductive output. While the risk of predation could not explain these long-term bonds, feeding cooperation seemed the most plausible explanation for group forming behaviour during the summer months.