Long-Term Estrogenic Effects Of 2,4,6-TCP On The Development And Reproduction Of Medaka

2,4,6-trichlorophenol (2,4,6-TCP) is a kind of important chemical material which could be much used as a antiseptic, food preservative and defoliant in industries like organic synthesis, paper making, and priting and dyeing. It could be detected in drinking water, river water, landfill leachate, and wastewater from chemical factories, sewage plants, and agricultural chemicals, etc. So,2,4,6-TCP may be potentially harmful to the aquatic ecosystem. The EPA has claimed that 2,4,6-TCP is, to some extent, carcinogenic substance.At present, research work on 2,4,6-TCP mostly lies on the acute and subacute researches on a certain physiological stage of the aquatic animals, while there has been less research work on the chronic influence researches exposed in the whole generation. In the natural environment and in most cases, the pollutants may be influential on the whole development and breeding process. And the results of the chronic research will be much closer to the actual environment, which contributes to people's comprehension of the physiological and ecological effect mechanism that the endocrine disruptors effect on the fish.medaka which is a kind of small fish originated from Japan, is easy to raise and very sensitive to the changes of water quality. The mature medaka is small with a full-length of 3 to 4 cm, and has strong reproductive capacity. In the beginning of 19^th century in Japan, the research on medaka has been started, which has been commonly used in physiology, ecology, endocrinology, and alike. Also, there have been systematic researches on breeding, feeding management, experiment operations, and so on. Nowadays, the medaka is widely used in toxicity test.With the medaka as the model organism, this dissertation researches into the influence of 2,4,6-TCP on the whole generation's development, reproductive performance, and the filial-generation's quality of the medaka.Take 20 pairs, each set, of medaka of sexual maturity and respectively expose them in the 2,4,6-TCP (0,10,30,100,100,10000μg/L),0.01%(v/v) DMSO of different concentration solvent as comparison. After 28 d of exposure, collect the roes and take statistics; choose one set and breed them in clear water, and another set still in the solvent until they get sexually mature; observe the embryos respectively; after the 5-week exposure of the mature fish, take some samples and make analysis.After the decline of the length and weight of the male, the dose-effect relationship takes on as the strength of the solvent intensifies. For the female, the length and weight declines in light concentration solvent as the concentration goes up, and picks up in high concentration solvent. The liver index of the male lowers with the solvent strength's increasing, while female's liver index doesn't take on significant changes in each solvent set of different concentration. The ovary index doesn't change markedly in sets of light concentration solvent; but it declines notably (p< 0.05) in sets of high concentration solvent.For medaka in the solvent, the number of laying-egg medaka doesn't make notable difference, but the egg laying amount of the female goes down, while, about the filial-generation's hatchability, the number of hatching days is of no marked changes during the feeding in the clear water. The hatching rate doesn't change significantly in solvent sets of light concentration, but goes down notably in solvent sets of high concentration (p< 0.05). The teratological rate begins to increase significantly in solvent sets of relatively high concentration (p< 0.05).