Isomer-specific determination of tetrachlorobenzyltoluenes (TCBT) in the technical mixture Ugilec 141 by capillary gas chromatography

Anthropogenic organic contaminants in sediments of the Lippe river, Germany

Sediment samples of the Lippe river (Germany) taken between August 1999 and March 2001 were investigated by GC-MS-analyses. These analyses were performed as non-target-screening approaches in order to identify a wide range of anthropogenic organic contaminants. Unknown contaminants like 3,6-dichlorocarbazole and bis(4-octylphenyl)amine as well as anthropogenic molecular marker compounds were selected for quantification. The obtained qualitative and quantitative analytical results were interpreted in order to visualize the anthropogenic contamination of the Lippe river including spatial distribution, input effects and time dependent occurrence. Anthropogenic molecular markers derived from municipal sources like polycyclic musks, 4-oxoisophorone and methyltriclosan as well as from agricultural sources (hexachlorobenzene) were gathered. In addition molecular markers derived from effluents of three different industrial branches, e.g. halogenated organics, tetrachlorobenzyltoluenes and tetrabutyltin, were identified. While municipal and agricultural contaminations were ubiquitous and diffusive, industrial emission sources were spatially isolated. Specific seasonal trends of distribution patterns were not observed.

Man-made chemicals found in remote areas of the world: the experimental definition for POPs

Members of the United Nations Economic Commission for Europe (UN-ECE) signed a legally binding protocol on persistent organic pollutants (POPs) in February 1998 under the Convention on Long-Range Transboundary Air Pollution. A treaty that intends to control the production, import, export, disposal and use of toxic chemicals that persist for decades in the environment has been formally signed at a conference in May 2001 in Stockholm. The 2001 POP treaty, like the 1998 LRTAP POP protocol, contains a provision on adding further chemicals to the initial group of twelve or fifteen. The occurrence of a compound or a group of compounds in so called remote and pristine areas, e.g. in the Artic or in the Southern Hemisphere, proves its stability under the chemical and biological conditions of the environment. Compounds identified in this way, in samples taken primarily in very remote regions of the planet, are classified by their environmental fate and global distribution as persistent organic pollutants (POPs), regardless of any political assessments.

Biotransformation rates of Ugilec 141 (tetrachlorobenzyltoluenes) in rat and trout microsomes

In vitro biotransformation rates of tetrachlorobenzyltoluene (TCBT) isomers 3,3',4,4'-Cl4-2-Me (TCBT 87), 3,3',4,4'-Cl4-5-Me (TCBT 88), and 3,3',4',5-Cl4-4-Me (TCBT 94) were determined using trout and rat hepatic microsomes. The disappearance of the TCBTs from the in vitro system followed first-order kinetics. The estimated biotransformation constants (k) for the rat ranged from 0.96 to 4.14 h(-1). Biotransformation rates for trout microsomes were much lower and ranged from 0.009 to 0.017 h(-1).

Comparison of bioconcentration factors of tetrachlorobenzyltoluenes in the guppy (Poecilia reticulata) and zebra mussel (Dreissena polymorpha)

Preliminary bioconcentration factors (BCFs) were determined of six tetrachlorobenzyltoluenes (TCBTs) in guppies (Poecilia reticulata). BCFs and rate constants were derived by an iterative integration method. With this method BCFs and rate constants can be derived from experimental data of a bioconcentration test, even if the concentration in the water is not constant and steady state has not been reached. Log BCF values of TCBTs in guppies ranged from 1.67 to 2.68 L.kg-1 on a wet weight basis. These values are much lower than the reported log BCF values of TCBTs in zebra mussels (Dreissena polymorpha) determined with the same method. Biotransformation of TCBTs in guppies as an explanation for the higher log BCF values in zebramussel is discussed.

Polychlorinated biphenyls in the environment

This review surveys the problems arising from the release of PCBs into the environment from the point of view of the analytical chemist. These problems are very complex and interdependent and so it is essential to recognize their mutual links rather than to separate one problem from another (sources of contamination, fate in the environment, toxic properties and particular capabilities, limitations and purposes of analytical methods). Prominent attention should be paid in the future to congener-specific analyses of "toxic" congeners using high-resolution gas chromatography and to toxicity-assessing biological methods.

Investigations on benzyltoluenes. I. Induction of microsomal cytochrome P-450 and UDP-glucuronosyltransferase by tetrachlorobenzyltoluenes and by the condensate

Tetrachlorobenzyltoluene (TCBT) (Ugilec 141) was investigated in induction experiments in male and female Wistar rats with long-term (50, 100 and 300 mg/kg p.o. daily for 28 days) and short-term administration (300 mg/kg once and 100 mg/kg daily for 4 days). The increase in total cytochrome P-450 did not exceed the factor of 1.9 compared to controls, while benzphetamine N-demethylase rose up to 3.5-fold the levels measured in controls, with very low induction of benzo(a)pyrene hydroxylase or ethoxyresorufin O-deethylase. Parallel investigations of UDP-glucuronosyltransferase showed induction of testosterone glucuronidation (1.7-fold). Administration (300 mg/kg body wt. once) of a pyrolysate of TCBT resulted in a marked increase in cytochrome P-450c dependent reactions (benzo(a)pyrene hydroxylase, ethoxyresorufin O-deethylase).