Permissible level of toxaphene residues in fish from the German market based on in vivo and in vitro effects to tumor promotion

Toxaphene is a chlorinated pesticide consisting of more than 200 congeners that are mainly chlorobornanes and chlorocamphenes. As the congeners exhibit different stability properties in the environment, only between 20 and 30 compounds can be observed in, e.g., fish, which are represented by technical toxaphene as a mixture. In human body, the congeners Parlar #26, #40, #41, #44, #50, and #62 are detected frequently. Three of them, #26, #50, and #62, pose a potential risk to human health due to their persistent characteristic. By using experimental results of a European Union study (MATT, 2000. Investigation into the Monitoring, Analysis and Toxicity of Toxaphene in Marine Foodstuffs, European Union, Brussels, Final report, FAIR CT PL.96.3131. Investigation into the Monitoring, Analysis and Toxicity of Toxaphene in Marine Foodstuffs), a reference dose related to tumor promotion was calculated for these representative persistent toxaphene congeners. In Germany, the sum of the congeners #26, #50, and #62 is defined as the official standard for toxaphene residues in food. In this work, different fish samples obtained from German markets were studied regarding their contamination with toxaphene congeners, presented either in sum, or as single constitutes. The obtained data were used to define the acceptable total concentration of the sum of Parlar #26, #50, and #62 with regard to prevention of tumor promotion in human. The results showed that the currently existing permissible level of the sum of these congeners (0.1 mg/kg) is higher than the acceptable concentration in fish samples determined by this work and calculated at ca. 0.090 mg/kg. It is therefore recommended to improve the permissible level of toxaphene in German food samples.