Comparison of cholin- and carboxylesterase enzyme inhibition and visible effects in the zebra fish embryo bioassay under short-term paraoxon-methyl exposure.

The acute zebra fish embryo test (Danio rerio Hamilton-Buchanan, 1822) is an accepted bioassay to assess the toxicity of waste water that may be used for the replacement of testing with adult fish. It is also suggested for chemical hazard characterization and assessment, although only a few groups of substances have yet been studied. Specifically acting substances such as neurotoxic insecticides pose a potentially hazard for non-target fish.

Membrane-assisted liquid-liquid extraction coupled with gas chromatography-mass spectrometry for determination of selected polycyclic musk compounds and drugs in water samples.

Selected polycyclic musk compounds and drugs were extracted from water samples by membrane-assisted micro liquid-liquid extraction. The two-phase extraction system consisted of polyethylene membrane bags filled with an organic solvent. Chloroform proved to be most suited as acceptor phase to extract caffeine, Galaxolide, Tonalide, phenazone and carbamazepine from aqueous samples.

Multi tracer test for the implementation of enhanced in-situ bioremediation at a BTEX-contaminated megasite.

At the Centre for Environmental Research Leipzig-Halle (UFZ) research site in Zeitz, Germany, benzene contaminates the lower of two aquifers with concentrations of up to 20 mg/l. Since the benzene plume has a minimum length of approximately 1 km, enhanced natural attenuation measures are being considered as a remediation strategy. This study describes the performance and evaluation of a multi-species reactive tracer test using the tracers fluorescein and bromide as conservative tracers and toluene as reactive tracer.

Determination of naturally occurring MTBE biodegradation by analysing metabolites and biodegradation by-products.

Methyl tert-butyl ether (MTBE) is one of the main additives in gasoline. Its degradation is known to be difficult in natural environments. In this study, significant MTBE degradation is demonstrated at a contaminated site in Leuna (eastern Germany).

Modeling the impact of a benzene source zone on the transport behavior of PAHs in groundwater.

Aquifers at industrial sites are commonly characterized by a multitude of contaminant source zones. Conceivably, dissolved contaminants originating from an up-gradient residual nonaqueous phase liquid (NAPL) source zone may be transported along the groundwater flow path into another residual NAPL source zone down-gradient. However, if and how contaminants from different zones may affect one another with regard to dissolution and transport has thus far been unknown.

Proposal to improve vertebrate cell cultures to establish them as substitutes for the regulatory testing of chemicals and effluents using fish.

Cultures of vertebrate cells are widely applied in mechanistic studies in human toxicology as well as in toxicity identification in ecotoxicology. As in vitro models, they display many advantages over whole animal experimentation, pertaining to such characteristics as availability, reproducibility and costs. As well, they satisfy the societal desire to reduce the number of animals in toxicology.

Development of a solvent-free, solid-phase in vitro bioassay using vertebrate cells.

Miniaturized bioassays offer many advantages in exploring the toxic potential of chemicals, including small sample volumes and compatibility with high-throughput screening. One problem common to miniaturized systems, however, is the loss of test chemicals because of sorption. The idea of the current study was to use the sorption phenomenon in a positive way.

Toxic potential of microcystin-containing cyanobacterial extracts from three Romanian freshwaters.

The aim of this study was to characterise for the first time the toxin profile and in vivo/in vitro toxicological effects of cyanobacteria obtained from three Romanian freshwater blooms. Two strains of Microcystis aeruginosa were isolated from blooms occurring in different fish ponds. As well, a complex bloom sample obtained from a recreational lake area and dominated by Microcystis aeruginosa and Microcystis viridis was explored.

Microcystin-LR induced cellular effects in mammalian and fish primary hepatocyte cultures and cell lines: a comparative study.

The impact of microcystin-LR, one of the most common cyanobacterial toxins, on liver and gut cells originating from mammals and fish was compared. Upon exposure of human and rainbow trout (Oncorhynchus mykiss) cell lines up to 2.5 microM microcystin-LR, no alteration in cell viability was observed as assessed with three fluorescent indicators dyes, CFDA-AM, Alamar Blue and neutral red.

Analysis of estrogenic effects by quantification of green fluorescent protein in juvenile fish of a transgenic medaka.

TheChgH-GFP strain of the teleost medaka contains a regulatory region of the estrogen-responsive choriogenin H (chgH) gene fussed to the green fluorescent protein (GFP) gene. The strain was developed for the identification of environmental estrogens by noninvasive analysis of GFP fluorescence. In the present study, a quantification method for GFP by image analysis was establishedand applied to the analysis of time- and concentration-dependent GFP fluorescence in juvenile fish.

Cadmium induces a novel metallothionein and phytochelatin 2 in an aquatic fungus.

Cadmium stress response was measured at the thiol peptide level in an aquatic hyphomycete (Heliscus lugdunensis). In liquid culture, 0.1 mM cadmium increased the glutathione (GSH) content and induced the synthesis of additional thiol peptides.

Cadmium and zinc response of the fungi Heliscus lugdunensis and Verticillium cf. alboatrum isolated from highly polluted water.

The aquatic hyphomycete Heliscus lugdunensis and the terrestrial fungus Verticillium cf. alboatrum, both isolated from a highly polluted surface water, were investigated for their tolerance against Cd and Zn. Hl-H4 showed a 50% growth inhibition at 0.

On line biomonitors used as a tool for toxicity reduction evaluation of in situ groundwater remediation techniques.

Success of groundwater remediation is typically controlled via snapshot analysis of selected chemical substances or physical parameters. Biological parameters, i.e.