Monitoring of iodinated X-ray contrast media in surface water

A monitoring programme was carried out in order to determine iodinated X-ray contrast media (ICM) in the River Danube and to investigate the raw water quality for drinking water production at Langenau waterworks. The study revealed that the maximum concentrations of ICM (over 500 ng l(-1) for diatrizoic acid and iopamidol) were found in 2h-composite samples taken from the downstream of the Ulm/Neu-Ulm metropolitan area. By means of a concentration profile over one month the highest ICM concentrations were observed on weekdays. The extended data evaluation with principal component analysis shows that the upstream and downstream samples had different pattern of variations in ICM concentration and also demonstrates a clear change in ICM composition by the discharge of municipal wastewater. In addition to load profiles of ICM, time-dependent plots of principal component 1 exhibited peaks, indicating a short-term discharge of ICM between the two sampling sites. In conclusion, a point source for ICM contamination between the sampling sites in Ulm upstream and Leipheim downstream seems to be the reasonable explanation for peak ICM concentrations. Due to the observed high variations of ICM concentrations in river, the evaluation of natural waters by means of a single analysis is not representative.     

Social stimulation,nuptial colouration,androgens and immunocompetence in a sexual dimorphic cichlid fish

The nature of the costs maintaining honesty of sexual signalling in inter- and intrasexual interactions remains a contentious issue. For carotenoid-based colour ornaments, it has been hypothesized that the honesty of the signal is enforced when carotenoid allocation to colour expression is traded off against carotenoid availability for immunocompetence. In addition, honesty is enforced if androgens required for colour expression are immunosuppressive. We tested whether there is a trade-off between colour expression and immunocompetence in a lek-breeding haplochromine cichlid fish, Pundamilia nyererei, from Lake Victoria with a carotenoid-based nuptial dress. First, we showed that expression of red nuptial colouration and social rank in a group were positively correlated. We then successfully manipulated the level of colour advertisement by socially stimulating individually housed males with a rival male: Stimulated males developed larger areas of red nuptial colouration and had higher levels of circulating 11-ketotestosterone (11-KT) than non-stimulated males. We subsequently tested the humoral immune response to a novel antigen (sheep red blood cells). There was no overall significant effect of social stimulation on antibody production, but in the stimulated males, the degree of red colouration and the antibody response were negatively correlated. This significant interaction between colour and treatment thus shows that the negative correlation between colouration and antibody production is dependent on the (manipulated) social environment. This study provides correlational and experimental evidence for a trade-off between expression of a sexual trait and one component of immune function in fish. We found no evidence for a direct effect of 11-KT on antibody production, and we discuss alternative mechanisms that could mediate the trade-off.     

Benthic response to sedimentation of a spring phytoplankton bloom: Process and budget

The response of benthos to sedimentation of the spring phytoplankton bloom in the Kiel Bight (Western Baltic Sea) is described in terms of biomass (ATP) and activity (heat production and ETS-activity). Input of the bloom (11.5 g C m^-2) over a period from March 25 to April 19, 1980 to the sediment surface was in the form of cells and fresh phytodetritus as indicated by low C/N ratios (7) and high energy charge values (0.78). Benthic microbial activity was immediately stimulated by this input as heat production doubled and the activity of ETS tripled over winter values within 12 d in the absence of a significant increase in ambient temperature. A comparison of the two activity parameters suggests that anaerobic metabolism is more important during the winter (February and March) than after input of the bloom. Meiofauna was not able to take part in the first activity outburst. Benthic ATP-biomass (excluding macrofauna) doubled in late April due to microbial production, and doubled again in early May when meiofauna started reproductive activity. For macrofauna a general statement was not possible, although the sediment surface feeder Macoma baltica commenced a build up of glycogen and lipid resources immediately following bloom input whereas Nephtys ciliata, feeding on sediment and small macrofauna, showed a less pronounced and delayed effect from this input. An energy budget based on heat production measurements was calculated. A daily heat loss of the benthic community of 21.7 KJ m^-2 d^-1 (35.5 KJ m^-2 d^-1) was found, when a depth of 3 cm sediment (5 cm) was assumed. Heat production of macrofauna contributed less than 5% of this activity. The input of the bloom was burned within 21 (13) d. Preliminary estimations for an annual budget suggest that the vertical transport of particulate organic matter via sedimentation can only explain 25% (15%) of the benthic activity in the shallow water ecosystem of the Kiel Bight. This indicates the presence of other sources of organic carbon such as benthic primary production or other transport processes providing carbon to the sediments.Publication No. 384 of the Joint Research Program of Kiel University (Sonderforschungsbereich 95)     

Monitoring of waste deposit derived groundwater contamination with organic tracers

Specific anthropogenic substances derived from seepage and leakage water from a waste deposit landfill were analysed in groundwater and drainage effluents using gas chromatography-mass spectrometry (GC/MS). Here, we demonstrate the application of an organic marker approach to study lateral and vertical distribution of contamination as well as the long-term emission behaviour. Source-specific and environmentally-stable pesticides, plasticisers and pharmaceuticals, such as N,N-diethyl toluamide, N-butyl benzene sulfonamide, clofibric acid, mecoprop and bisphenol A, were quantitatively analysed. A distinct lateral expansion was detected. Although temporal variations were high, no significant trend was observed.     

Levels and pattern of volatile organic nitrates and halocarbons in the air at Neumayer Station (70 degrees S), Antarctic

Levels and patterns of C1-C4/C9 organic nitrates were measured for the first time in Antarctica. The sampling was done by adsorptive enrichment on Tenax TA followed by thermodesorption cold-trap high resolution capillary gas chromatography with electron capture detection. 2-70 1 air on-column have been analyzed this way. C1-C9 alkyl mononitrates, C2-C4 alkyl dinitrates, C2-C4 hydroxy alkyl nitrates, and halocarbons could be identified in air samples collected near the German Neumayer Research Station, Antarctica, in February 1999. Volatile biogenic and anthropogenic halocarbons were used to assess the origin of the air parcels analyzed. The average concentration measured for sigmaC2-C6 alkyl nitrates was in the range of 9.2 +/- 1.8 ppt(v), while the sum of the mixing ratios of six C2-C4 hydroxy alkyl nitrates was in the range of 1.1 +/- 0.2 ppt(v). Moreover, C2-C4 alkyl dinitrates were found at levels near the detection limit of 0.1-0.5 ppt(v). The concentrations of organic nitrates found in Antarctic air represent ultimate baseline levels due to chemical and physical loss processes during long-range transport in the air. The South Atlantic and the Antarctic Ocean as a general secondary source for organic nitrates in terms of an air/sea exchange equilibrium has to be evaluated yet, but it seems logical. Our results confirm the common assumption that there are no biogenic marine sources of C2-C9 organonitrates. We have found a level of > 80 ppt(v) for methyl nitrate. This level if it can be confirmed in a systematic survey requires a strong biogenic source of methyl nitrate in the Antarctic Ocean.     

(M)VOC and composting facilities. Part 2: (M)VOC dispersal in the environment

BACKGROUND, AIMS AND SCOPE: Composting facilities are known to release odorous volatiles due to biodegradation of municipal waste and plant residues. Although odour perception and its grading is influenced by experience, attitude and adaptation, these emissions have created a lack of acceptance for residents in the vicinity of composting facilities. Enclosure of compost pile halls, ventilation systems and biofilters are often insufficient to minimise the burden of compost-derived compounds in the air. Moreover, economic considerations forced smaller communities to establish less sophisticated facilities with open storage areas and other relevant sources for wind-borne dispersal of bioaerosols. Aim of the present study was to characterise the immission and dispersal of microbial volatiles (MVOC) and, besides, to find coincidences between MVOC and compost odour. METHODS: In the course of this study, the surroundings of two composting facilities, differing in their type of process engineering, were investigated for emission of volatiles in the environment. Both microbially and plant-derived substances were assessed, several of which have low odour thresholds. Air samples were taken in distances ranging from 50 to 800 m in a downwind direction from each facility. RESULTS AND DISCUSSION: Compost-derived and microbial volatile organic compounds (MVOC) were found at distances of up to 800 m from the composting facilities. Terpenes like alpha-pinene, camphene and camphor were the dominant compounds and coincided with typical compost odour, whereas several typical MVOC were not found at greater distances. The terpenes in combination with certain MVOC may play an important role in the perception of compost odour. Exposure concentrations were not of toxicological relevance, but sensory irritation and psychohygienic effects due to an annoyance potential of such compounds should not be dismissed. RECOMMENDATIONS AND OUTLOOK: Although terpenes are generally associated with pleasant odour characteristics, they seemed to contribute to malodours in a mixture with other VOC, in this context of volatile waste from compost facilities. Malodorous emissions from biowaste have to be considered as sources of health complaints and the investigation of mixtures of compost-derived volatiles is still inevitable. Exposure levels have to be discussed taking VOC mixtures into account. Within composting facilities, technical devices have to be improved to minimise dispersal of volatiles to prevent residents from immissions eventually causing health complaints.     

Enhanced experimental flexibility and control in ecotoxicological mesocosm experiments--a new outdoor and indoor pond and stream system

Scope The German Federal Environmental Agency has put into operation a new modular mesocosm system consisting of eight outdoor and eight indoor ponds and streams in order to investigate fate and effects of chemicals and municipal wastewater in aquatic ecosystems. General design and special characteristics are given to demonstrate the wide range of possibilities for experimental research. - General design. Each of the 16 streams with riffle and pool sections can be varied in length up to 106 m. The streams can be run as circular or flow-through systems at a flow velocity of 0.02 to 0.6 m/s. Physico-chemical standard parameters are measured on-line. The 16 ponds, which can be connected to the stream systems, are equipped with drainage and pore water-sampling devices for simulating processes in the littoral zone including influent and effluent ground water flow. Perspectives Since the highly flexible and controllable construction also allows treating a wide range of hydrological and ecological experiments external institutions are invited to submit proposals.