Umweltschäden durch Heizöl nach Hochwasserereignissen

Background Due to high safety measures in production, transport and storage of fuel oil it rarely occurs, that fuel oil will be released in the environment. One exception of this experience was the fuel oil releases of private fuel oil tanks during the “century flood” 2002 in Germany. By order of IWO (Institut für wirtschaftliche Oelheizung e.?V.), the authors investigated the environmental behaviour of fuel oil after flood incidents. Aim Due to the fast spreading of the fuel oil on water surfaces and the contamination of huge areas one expects large environmental harm. For appraisal the behaviour of fuel oil in water and soil must be studied in detail as well as the effect on high and low developed animals and plants, on water organisms and on the flora and fauna of soil. From the valuation of the environmental harm official measures and measures of precaution and safety by manufacturer and user of private fuel oil installations can be derived. Main features For considering the various aspects the authors studied the extensive analyses of the special measuring programme of Saxony-Anhalt, used interviews of concerned persons (private persons and officials), aerial photos, extensive study of literature including eco-toxicological investigations, experiences of more than 70-years applications of fuel oil in plant protection and practical experiences at large field redevelopment of oil damages following averages and accidents. The authors valuated on the base of results of analyses and on own calculations. Results The release of fuel oil in the air is no particular problem because about 40?% of the oil fast evaporate and will be decomposed to carbon dioxide and water. In addition to the evaporation a characteristic behaviour is fast spreading of the fuel oil on the water surface to very thin layers. For a typical coloured oil layer e.?g. one cubic meter of oil is spread on a water surface of about 3?km², this corresponds to 3?ml/m² surface and contaminates the soil after drying up with about 3?µg/kg soil some orders less than the natural content of hydrocarbons in soil. Because of the absorption capacity of soil and the microbial decomposition by everywhere existing hydrocarbons decomposing micro-organisms the oil infiltrates only a few centimetre and will be decomposed in a few months, so that ground water detriments not arise practically. By measurements a few months after fuel oil release in the flood 2002 oil components in the soil could not be detected. Discussion Acute injuries of micro-flora and -fauna in soil and water by fuel oil cannot be excluded from the first. Thus the limiting values of injuries for some water organisms are below 1?mg/l. According to the special measuring programme at the flood 2002 in Saxony-Anhalt however the measured values were mostly wide below of this limit. In detail the spreading and evaporation of fuel oil on water surfaces, the propagation and decomposition of fuel oil in soil will be described. A quantitative valuation of fuel oil distribution in a real flood incident will be given. Conclusions Particular measures of redevelopment of soil for fuel oil release after flood incidents are not necessary normally. Even at the redevelopment after transport damages or at devastated sites with essential higher oil contaminations of soil in comparison to fuel oil release after flood incidents high decomposition rates are obtained by normal soil improving measures supporting the natural micro-organisms in reducing the hydrocarbon concentration for 70–90?% after a few months. Perspectives With the described results a realistic valuation of the environmental harm of fuel oil release after flood incidents could be given. From this qualified measures can be derived for official decisions and precautionary and reliable activities at fuel oil installations of flood endangered areas.     

Refuge sharing network predicts ectoparasite load in a lizard

Living in social groups facilitates cross-infection by parasites. However, empirical studies on indirect transmission within wildlife populations are scarce. We investigated whether asynchronous overnight refuge sharing among neighboring sleepy lizards, Tiliqua rugosa, facilitates indirect transmission of its ectoparasitic tick, Amblyomma limbatum. We fitted 18 neighboring lizards with GPS recorders, observed their overnight refuge use each night over 3 months, and counted their ticks every fortnight. We constructed a transmission network to estimate the cross-infection risk based on asynchronous refuge sharing frequencies among all lizards and the life history traits of the tick. Although self-infection was possible, the network provided a powerful predictor of measured tick loads. Highly connected lizards that frequently used their neighbors’ refuges were characterized by higher tick loads. Thus, indirect contact had a major influence on transmission pathways and parasite loads. Furthermore, lizards that used many different refuges had lower cross- and self-infection risks and lower tick loads than individuals that used relatively fewer refuges. Increasing the number of refuges used by a lizard may be an important defense mechanism against ectoparasite transmission in this species. Our study provides important empirical data to further understand how indirectly transmitted parasites move through host populations and influence individual parasite loads.     

Effects of sample preparation on the measurement of organic carbon,hydrogen, nitrogen,sulfur, and oxygen concentrations in marine sediments

The elemental composition of marine sediment provides useful information for the study of environmental processes including biogeochemical cycling and contaminant partitioning. It is common practice to acidify marine sediment samples to remove carbonate before measuring the concentrations of organic carbon (C). To date, however the effects of acidification on the concentrations of hydrogen (H), nitrogen (N), sulfur (S) and oxygen (O) in marine sediments have not been explicitly addressed. Acidification may contaminate or alter the sediment samples and create experimental artifacts affecting the validity of resulting H/C, C/N and O/C ratios. The objective of this study was to quantify how various preparation techniques affect the measured concentrations of C, H, N, S and O in marine sediments. Effects of four different pretreatments: unacidified (whole), acidification by HCl vapor, acidification by direct addition of HCl, and combustion were evaluated using five marine sediments and a standard reference material. The magnitude of carbonate loss between the vapor and direct acidification treatments was evaluated using stable C isotope analysis. Carbonates were most effectively removed by direct addition of HCl; and our results agree with findings of other studies which found direct addition of HCl to be the most accurate method for measuring organic C. However, the acid treatments elevated the apparent concentration of H and O; and in a few cases concentrations of N and S were significantly affected by acidification. In general, combustion significantly reduced all elemental concentrations compared to the whole sample. Based on these results, we recommend analysis of the untreated whole sediment for determining N, H, O, and S.     

POLYNOMIAL-BASED DISAGGREGATION OF HOURLY RAINFALL FOR CONTINUOUS HYDROLOGIC SIMULATION1

Hydrologic modeling of urban watersheds for designs and analyses of stormwater conveyance facilities can be performed in either an event-based or continuous fashion. Continuou simulation requires, among other things, the use of a time series of rainfall amounts. However, for urban drainage basins, which are typically small, the temporal resolution of the rainfall time series must be quite fine, and often on the order of 5 to 15 minutes. This poses a significant challenge because rainfall-gauging records are usually kept only for hourly or longer time steps. The time step sizes in stochastic rainfall generators are usually also too large for application to urban runoff modeling situations. Thus, there is a need for methods by which hourly rainfall amounts can be disaggregated to shorter time intervals. This paper presents and compares a number of approaches to this problem, which are based on the use of polynomial approximating functions. Results of these evaluations indicate that a desegregation method presented by Ormsbee (1989) is a relatively good performer when storm durations are short (2 hours), and that a quadratic spline-based approach is a good choice for longer-duration storms. Based on these results, the Ormsbee technique is recommended because it provides good performance, and can be applied easily to long time series of precipitation records. The quadratic spline-based approach is recommended as a close second choice because it performed the best most consistently, but remains more difficult to apply than the Ormsbee technique. Results of this study also indicate that, on average, all of the disaggregation methods evaluated introduce a severe negative bias into maximum rainfall intensities. This is cause for some well-justified concern, as the characteristics of runoff hydrographs are quite sensitive to maximum storm intensities. Thus, there is a need to continue the search for simple yet effective hourly rainfall disaggregation methods.     

Effects of 3-chlorobiphenyl on photosynthetic oxygen production, glutathione content and detoxication enzymes in the aquatic macrophyte Ceratophyllum demersum

Organic contaminants of environmental concern such as polychlorinated biphenyls have dispersed widely throughout the ecosystems and accumulate in living organisms, and a variety of adverse biological effects have been reported. In this study, we investigated the effects of 3-chlorobiphenyl in the aquatic macrophyte Ceratophyllum demersum and the capacity of its detoxication system. After 24 h of exposure to various concentrations of 3-chlorobiphenyl, the total glutathione content (tGSH) was determined and the dose-response curves for glutathione reductase (GR) and microsomal/cytosolic glutathione S-transferases (m- and c-GSTs, respectively) were established. C. demersum showed a decrease of photosynthesis after exposure to 3-chlorobiphenyl, although only significantly at 5 microgl(-1). At 0.005 and 0.05 microgl(-1) the GR, m-GST and c-GST activities were significantly increased and concomitantly a non-significant effect on total GSH was observed. At 0.5 microgl(-1), GR as well as c-GST were still significantly induced, while at 5 microgl(-1) none of the enzymes were activated. These results show that detoxication through glutathione conjugation takes place at low concentrations of 3-chlorobiphenyl, while concentrations in the order of parts per billion cause the inactivation of the enzymatic systems evaluated, enough to place C. demersum in an important physiological stress condition.     

Rethinking Tropical Forest Conservation: Perils in Parks

Abstract: According to some conservationists, large, pristine, uninhabited parks are the defining criterion of success in conserving tropical forests. They argue that human residents in tropical forests inevitably deplete populations of large animals through hunting, which triggers a chain reaction of ecological events that greatly diminish the conservation value of these forests. Hence, they believe that removal of people from tropical forests is an essential step in the creation of successful parks and in the conservation of nature in the tropics. This approach can lead to undesirable consequences, however. Forest residents—and rural people generally—are potent political actors in tropical forest regions and an essential component of the environmental political constituencies that are necessary for the long-term conservation of tropical forests. In Amazonia and elsewhere, rural people are defending far bigger areas of tropical forest from unfettered deforestation and logging than are parks, thereby conserving the ecological services provided by these forests and the majority of their component plant and animal species. Moreover, the data are too sparse to judge the effects of forest peoples on populations of large forest animals. The establishment of pristine, tropical forest parks is an important conservation goal, but the exclusive pursuit of this goal undermines the broader objectives of conservation when it identifies forest residents and other rural people as the enemies of nature.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.