Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Norbert Theobald is active.

Publication


Featured researches published by Norbert Theobald.


Chemosphere | 2001

The occurrence of xenoestrogens in the Elbe river and the North Sea.

O.P Heemken; Heinrich Reincke; Burkhard Stachel; Norbert Theobald

The xenoestrogens Bisphenol A (BPA), p-alkylphenols and p-alkylphenol ethoxylates were determined in water samples of the North Sea, the Elbe river, and its tributaries Schwarze Elster, Mulde, Saale and the Weisse Elster. The sampling sites of the Elbe river reached from Schmilka at the German-Czech border to Cuxhaven at the estuary. Samples of the North Sea were taken in the German Bight. Additionally, freshly deposed sediments of the River Elbe and its tributaries were analyzed. Partitioning coefficients of these compounds for the distribution between suspended particulate matter (SPM) and the aqueous phase were calculated for samples of the River Elbe at sampling site Geesthacht. The analytical procedure consisted of liquid-liquid extractions of the acidified water samples using dichloromethane. Sediments and SPM samples were extracted by Accelerated Solvent Extraction with n-hexane/acetone. Following a clean-up by HPLC, the analytes were derivatized with heptafluorobutyric acid anhydride and quantified using GC-MSD. The concentration ranges of the compounds analyzed in water samples of the Elbe river were as follows (in ng l(-1)): BPA 9-776, alkylphenols 10-221 and alkylphenol ethoxylates 18-302. In sediment samples the concentrations were (in microg kg(-1) dry mass): BPA 66-343, alkylphenols 17-1378 and alkylphenol ethoxylates 30-1797. In samples of the North Sea the concentrations were generally about 1 order of magnitude lower. As shown by the concentration profiles following the River Elbe into the North Sea, the Elbe river must be considered as a major pollution source for the North Sea concerning the compounds analyzed. The SPM/water-partitioning coefficients calculated (mean values) amounted to: BPA 4.50, alkylphenols 5.52-5.58 and alkylphenol ethoxylates 5.60-6.38. A comparison of the results with data from other surface waters showed that concentrations of these xenoestrogens in the River Elbe and its tributaries were relatively low. The evaluation of the data based on the lowest observable effect concentration (LOEC) for alkylphenols (endpoint: vitellogenin synthesis in male trout) indicated that the concentrations were well below the effectivity threshold.


Environmental Pollution | 2003

Xenoestrogens in the River Elbe and its tributaries.

Burkhard Stachel; Ute Ehrhorn; Olaf-Peter Heemken; Peter Lepom; Heinrich Reincke; Georg Sawal; Norbert Theobald

4-Alkylphenols, 4-alkylphenol ethoxylates, 4-alkylphenoxy carboxylates, bisphenol A, bisphenol F, 4-hydroxyacetophenon, 4-hydroxybenzoic acid and steroid hormones were analyzed in water samples of the River Elbe and its tributaries Schwarze Elster, Mulde, Saale, Havel and Schwinge. Additionally, freshly deposited sediments (FDS, composite samples) of the River Elbe and its tributaries were analyzed. The concentrations in water samples ranged from (in ng/l): bisphenol A 4 to 92, branched nonylphenol 13 to 87, branched nonylphenol ethoxylates <0.5 to 120, 4-tert. nonylphenoxy carboxylates <10 to 940 and 4-hydroxybenzoic acid 4 to 12. Steroid hormones were only detected in the Czech tributaries Jizera and Vltava in concentrations near the limit of quantification. In FDS samples the concentrations amounted to (in g/kg d.w.): bisphenol A 10-380, branched nonylphenol 27-430, branched nonylphenol ethoxylates 24-3700, nonylphenoxy carboxylates <50 and 4-hydroxybenzoic acid 23-4400. Increased bisphenol A concentrations were found in water and FDS samples taken from the Czech-German border at Schmilka and the mouth of the Schwinge (only water sample). According to studies conducted in the Elbe Estuary and the German Bight, the River Elbe must be considered as a major source of pollution for the North Sea in respect of the compounds analyzed. A comparison of bisphenol A concentrations, 4-alkylphenols and the corresponding ethoxylates analyzed in the River Elbe and its tributaries with those found in other German surface waters indicated a low level of contamination. The evaluation of the data based on LOEC-values indicated that the concentrations were well below the effectivity threshold for some 4-alkylphenols. According to recent ecotoxicological investigations, for example, with prosobranch snails, bisphenol A concentrations found in water samples of the River Elbe and its tributaries may well be detrimental to aquatic organisms. On the basis of the monitoring data and its implications for estrogenic potency the inclusion of bisphenol A in the list of priority substances (European Union Directive 2000/60/EC, Annex X) should be considered.


Marine Pollution Bulletin | 2009

Biomonitoring of TBT contamination and imposex incidence along 4700 km of Argentinean shoreline (SW Atlantic: From 38S to 54S)

Gregorio Bigatti; Mónica A. Primost; Maximiliano Cledón; Andrés Averbuj; Norbert Theobald; Wolfgang Gerwinski; Wolf Arntz; Elba Morriconi; Pablo E. Penchaszadeh

The imposex incidence and TBT pollution were investigated along 4,700km of Argentinean coast, including city harbors and proximal zones without marine traffic. We analyzed 1805 individuals from 12 gastropod species, including families Volutidae, Muricidae, Nassariidea, Calyptraidae, Marginellidae, and Buccinidae, and found the imposex phenomenon for the first time in six species. In high marine traffic zones, TBT pollution was registered and the percentage of imposex was high, while these occurrences were null in areas without boat traffic. The species that best reflect the degree of imposex were those inhabiting sandy/muddy or mixed bottoms. TBT determination and imposex incidence indicate that pollution was focused only in ports with high marine traffic or in areas where ship hulls are painted. This is the first report of an imposex-sediment approach to evaluate organotin contamination along the coast of a South American country.


Marine Pollution Bulletin | 2010

Sources of polyfluoroalkyl compounds in the North Sea, Baltic Sea and Norwegian Sea: Evidence from their spatial distribution in surface water

Lutz Ahrens; Wolfgang Gerwinski; Norbert Theobald; Ralf Ebinghaus

The spatial distribution of 15 polyfluoroalkyl compounds (PFCs) in surface water was investigated in the North Sea, Baltic Sea and Norwegian Sea. In addition, an interlaboratory comparison of the sampling techniques and analysis was conducted. Highest concentration in the North Sea was found near the coast, whereas the summation operatorPFC concentration decreased rapidly from 18.4 to 0.07 ng l(-1) towards the open North Sea. The river Elbe could identify as a local input source for PFCs into the North Sea, whereas perfluorobutanoic acid (PFBA) was transported into the sampling area with the easterly current. In contrast to the North Sea, the distribution of PFCs in the Baltic Sea was relatively homogenous, where diffuse sources dominated. In general, the composition profile was influenced from local sources caused by human activities, whereas atmospheric depositions of here analysed PFCs were negligible, but it could have possibly an influence on low contaminated sites like the open North Sea or Norwegian Sea.


Environmental Toxicology and Chemistry | 2007

Emerging pollutants in the North Sea in comparison to Lake Ontario, Canada, data

Jens Arne Andresen; Derek C.G. Muir; Daisuke Ueno; Colin Darling; Norbert Theobald; Kai Bester

In the present study, the concentrations and fate of contaminants such as organophosphate flame retardants and plasticizers, musk compounds such as galaxolide (HHCB), tonalide (AHTN), musk ketone and musk xylene, the bactericide triclosan, as well as the metabolites HHCB-lactone and triclosan-methyl were compared in the aqueous phase of the German Bight (North Sea). The concentrations of these compounds were around 1 to 10 ng/L in nearshore areas, and the concentrations were lower in the more pristine areas. The highest concentrations were determined for tris-(2-chloro-isopropyl) phosphate in the North Sea with concentration exceeding 10 ng/L even for the offshore samples. The samples contained 1 to 20 ng/L chlorinated organophosphates, approximately 1 ng/L nonchlorinated organophosphates, and 0.3 to 3 ng/L fragrance compounds. Some samples from Lake Ontario (Canada) were analyzed in comparison. Per capita emissions were calculated for both regions. These emissions were compared and turned out to be very similar for the Canadian and German locations. For the North Sea, some observations concerning stability, dilution, and degradation, as well as sources of the respective substances, were performed. These data indicate that the chlorinated organophosphates and some musk fragrances exhibit half lives exceeding the residence times and thus can be considered to be persistent in this ecosystem. In the German Bight, the river Elbe is the dominating source for the more hydrophilic compounds, such as chlorinated organophosphate flame retardants, which are diluted only into the North Sea. However, for the more lipophilic compounds such as the musk fragrances, different input patterns as well as distribution patterns are relevant, though the river Elbe is still a major source of pollution to the German Bight of the North Sea. The data seem to indicate either relevant inputs further west of the sampling area or mobilization from the sediments.


Science of The Total Environment | 1997

Results of non-target screening of lipophilic organic pollutants in the German Bight I: benzothiazoles

Kai Bester; Heinrich Hühnerfuss; Wilfried Lange; Norbert Theobald

Abstract The presence of benzothiazole and methylthiobenzothiazole in estuarine and marine waters is shown for the first time. A method for the quantification of these compounds is described and the results of the quantification in water from the North Sea are given. The concentrations range from 0.04 to 1.37 ng/l methylthiobenzothiazole in the North Sea, while 55 ng/l were found in the Elbe river. The values for benzothiazole vary from 0.25 to 2.7 ng/l.


Journal of the Marine Biological Association of the United Kingdom | 2006

Imposex and organotin compounds in marine gastropods and sediments from the Mar del Plata coast, Argentina

Maximiliano Cledón; Norbert Theobald; Wolfgang Gerwinski; Pablo E. Penchaszadeh

The occurrence of imposex in Adelomelon brasiliana during two consecutive years near to Mar del Plata (the principal fishery port of Argentina) and its relation to tributyltin (TBT) and dibutyltin (DBT) content in muscle tissue and digestive gland was investigated using gas chromatography. Percentage of imposex affected females increased to over 80% in spring and summer of both years. However, its intensity, given by the relative penis size index (RPSI), fluctuated around low values. Adelomelon brasiliana digestive gland samples showed a very low concentration of TBT (36-46 ng/g dry weight). Egg capsules presented normal viable embryos, which had TBTconcentrations similar to the capsule wall (15 ng/g) while the intracapsular liquid was only 2 ng/g, similar to the sediment concentration. The proportion and distribution of butyltin compounds (BTs) in sediments indicate a major contamination event.


Fresenius Journal of Analytical Chemistry | 1995

Mass spectrometric investigations of water extracts of the river Elbe for the determination of potential inputs of pollutants into the North Sea

Norbert Theobald; Wilfried Lange; Winfried Gählert; Florian Renner

A non-target screening by gas chromatography-mass spectrometry has been carried out on water extracts of the river Elbe in order to obtain an overview of organic compounds being dissolved or bound to suspended matter in the Elbe. Samples of 1001 volume were taken at the freshwater border at Stade and extracted by liquid-liquid extraction with pentane. Before GC-MS analysis, the water extracts were fractionated into 15 subsamples by HPLC on an SiO2 column. A sensitivity of ca. 50 to 250 pg/l was reached for the GC-MC analysis. Several hundreds of natural and anthropogenic compounds could be identified or at least grouped into a compound class. The presence of a number of compounds could be verified from earlier investigations, in addition a great number of anthropogenic compounds were described which have previously not been reported for the river Elbe.


Environmental Pollution | 1998

Results of non target screening of lipophilic organic pollutants in the German Bight. IV: Identification and quantification of chloronitrobenzenes and dichloronitrobenzenes

Kai Bester; Robert Gatermann; Heinrich Hühnerfuss; Wilfried Lange; Norbert Theobald

Within this study all three monochloronitrobenzenes were identified and quantified in water of the German Bight of the North Sea. The concentrations ranged from <0.02 to 8.9 ng/L. The latter high value was found in the estuary of the River Elbe, though. Additionally, 2,5-dichloronitrobenzene and 3,4-dichloronitrobenzene were identified and quantified. The concentrations of these compounds ranged from <0.05 to 7.7 ng/L. The major path of input for the chloronitrobenzenes to this marine area is the River Elbe. A method for quantification is described.


Water Research | 2000

Results of non target screening of lipophilic organic pollutants in the German Bight V: Xanthen-9-one

Kai Bester; Norbert Theobald

The presence of xanthen-9-one in estuarine and marine waters is shown for the first time. A method for the quantification of this oxy-PAH is described and results are given for water samples from the North Sea. The concentrations range from 0.08 to 0.68 ng∗l−1 in the sea, while 3.7 ng∗l−1 were detected in the water of the estuary of the river Elbe. This compound can possibly be used as a tracer for anthropogenic contamination attributed to the combustion of fossil fuels, especially in automobile engines.

Collaboration


Dive into the Norbert Theobald's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge