Embryotoxicity of Nine Seed Mordants in the Chick Embryo . the Chest Method

Peterka M., M. Tu~ek, D. Vesely: EmbryotoxicityoJNineSeedMordants in the Chick Embryo the CHEST Method. Acta vet. Bmo 1996, 65:213-217. The seed mordants Agronal Super, which contains the organic mercury (5.4% phenylmercurychloride), has appeared to induce poisoning and even death of many people and animals. Minimal single embryotoxic doses of Agronal Super were estimated in 2-4-day old chick embryos using the CHEST method and compared with the minimal embryotoxic doses of other g seed mordants without mercury. Minimal embryotoxic doses (the beginning of the embryotoxicity range) of Agronal Super were between 0.1-1.0 JLglembryo. The seed mordants without mercury appeared to be less toxic: The minimal embryotoxic doses of Bay tan Combi, Bay tan Universal, Fundasol, Quinolate and Wolfen Thiuram were between 1-10 JLg/embryo. Novozir and Sibutol had minimal embryotoxic doses within the range 10-100 JLglembryo. The least dangerous appeared the seed mordant Vincit, which produced no embryotoxic effect, even after administration of the highest doses (100 JLg/embryo). Our results demonstrated the difference of several orders of magnitude between embryotoxic doses of Agronal Super and other g seed mordants. Replacement of seed mordants containing organic mercury (e.g. Agronal Super) by new ones with minimal or no embryotoxic effect (e.g. Vincit) is advisable. Embryotoxicity, chick embryo, mercury, seed mordant, Agronal Toxic effects of the mercury are known from old times. The development of chemistry entailed many new anorganic as well as organic mercury compositions. Some of them were or still are used as seed mordants. It has been reported that the organic mercury compounds used as seed mordants caused poisoning and even death of many people and animals (WHO 1976; Friberg et al. 1979; Tucek and Tucek 1981; Cibulka 1991). Application of seed mordant substances containing alcylmercury has been already forbidden in most of industrial countries. Also in our country, the last stores of Agronal Super, whose effective component phenylmercurychloride contains 1.6 5.4% of mercury, have been already consumed. Approximately 85% of seed, before all wheat and barley, were preserved with Agronal Super. Each year, 10% from the total amount of manufactured mercury (Le. 20 tons) was consumed for yearly Agronal production (900-1000 tons). The average usage of Agronal Super was 800 tons during the last years. In the world as well as in the Czech Republic, a new generation of seed mordants without alcylmercury component started to be produced and applied. It is very important to know toxicity of the new seed mordants and use preferably only the least toxic ones. The chicken embryo assay has been successfully used for determination of the toxicity of various chemical substances such as drugs, food additives, mycotoxins and airborn particles (Nishigori et al. 1992; Verret et al. 1980; Vesely et al. 1992; Matsumoto 1988). Ni shigori et al. (1992) have developed a screening test using 15-day-old hen' s fertile eggs (Hen-s fertile Egg Screening Test, HEST) for evaluation of activity and toxicity of drugs. In comparison with mammalian models, tests employing chick embryos are cheap and rapid.