Humane approches to toxicological evaluations of industrial chemicals

NIZNHNY NOVGOROD UNIVERSITY DEPARTMENT OF ECOLOGY Summary HUMANE APPROCHES TO TOXICOLOGICAL EVALUATIONS OF INDUSTRIAL CHEMICALS Made by Loginov V. V. Scientific advisor d. b. s., prof. Gelashvili D. B. NIZHNY NOVGOROD, 1999 There are millions of chemical substances recorded in the scientific literature with many more being added annually through the endeavors of chemists in industry and academia (Tаble 1). Tens of thousands of these substances are used in commerce, as demonstrated by the publication of inventories in the European Economic Community under the Sixth Amendment to the Dangerous Substances Directive and in the United States through the Toxic Substances Control Act (TSCA). The enormous growth of the chemical industry, coupled with the potential for increased

exposure of the population to chemicala, has generated growing public concern and an awareness of the need for correct safety aascsfunent. The toxicological assessment, therefore, of the potential health hazards posed by chemical substances to which humans and animals may be directly or indirectly exposed Is a rational requirement of civilized society. TABLE 1 Chemical Substances Known Group Approximate number Documened chemicals (Chemical Abctracts) 7,000,000 Increase per annum 400,000 EINECS (European Inventory of Existing Commerical Chemical Substances) 95,000 ECOIN (European Core Inventory) 34,000 Known drugs 4,000 Known pesticides 1.500 Over the last 40 years or so, the use of toxicology as a predictive science has developed immensely. This growth has been stimulated by an

increasing amount of legislation that ensures that relevant toxiclty studies, which include whole-animal studies, are completed on a vari­ety of chemical substances. The knowledge of whether a chemical substance has the potential to poison a biological system, cause irritation on contact with the external tissues or cause an allergic response, Is imiwrtant in establishing a safer environment. An awareness of these properties assists society in ensuring correct and safe procedures when people or animals are exposed to chemicals. Trade in chemicals is international, and therefore understanding the hazards of chemical substances and identifying those hazards on the label requires an international language of hazard warning. Acute toxic effects derived from animal studies have been

the subject of standardization for classification and labeling for many years. The language of the label-TOXIC, VERY TOXIC, HARMFUL, IRRITANT, CORROSIVE-is understood by the international community. While society demands health and safety as prerequisites for the development, manufacture, and use of chemical substances, society is also concerned with the welfare and humane treatment of the labora­tory animals used in toxiclty testing. This, of course, poses a potential paradox since the complete assessment of the toxicity of chemical sub­stances involves the use of laboratory animals. Codes of practice have been established in many countries to promote humane procedures. The Organisation for Economic Co-operation and Development (OECD) haa made enormous progress in

standardizing toxicological testa to reduce barriers to trade caused by varying protocol requirements between nations, and this has had a significant influence in reducing the number of animals used in toxicological studies. The use of live animals as experimental models is not in itself inhumane, although this view is not shared by everyone. In vitro systems that avoid the use of live animals have been developed for predicting the mutagenic, and possibly carcinogenic, potential of chemical substances, one such Is the Salmonella typhimurium reverse mutation assay (Ames test). This has stimulated many toxicologists, biologists, pharmacologists and biochemists to consider whether alternative in vitro/ex vivo procedures could minimize the need for whole-animal studies in other areas