Bioaccumulation Of Typical Endocrine Disruptors In Fish

Endocrine disruptoring chemicals (EDCs) are natural, exogenous and synthetic chemicals that act as mimetic to natural hormones. When EDCs are absorbed by the organisms, they can antagonize the action or modify the synthesis, release, transport and metabolism of the endogenous hormones. Exposuring to ECDs has been associated with many diseases in organisms, like inhibiting or activateing the endocrine system, breaking the stability of homeostasis and destroying the processes of reproduction and development. ECDs are released to the environment through many ways, such as contaminated water and air, life waste,etc. They can be detained in the environment for a long time and have characteristics of long distance transportation, bioaccumulation and biomagnification. Currently, ECDs are divided into two categories:One is the natural and synthetic hormones; the other is synthetic chemical contaminants. Researchs on ECDs mainly focused on their endocrine disrupting action and toxicological effects, but few on bioaccumulation.17β-estradiol (E2) and bisphenol A (BPA), typical endocrine disruptoring chemicals in the environment, are ovarian steroid synthesis of endogenous estrogen and synthetic chemical contaminant respectively. In the article, researchs on the bioaccumulation of E2 and BPA in fish through aqueous and dietary exposure will be explored with the purpose of understanding their accumulating and depurating abilities, calculating their biological amplification factor(BMF) and bioconcentration factor(BCF) in fish and supplementing bioaccumulation datas of endocrine disruptoring chemicals.The research will have great significance to the environmental risk assessment of endocrine disruptoring chemicals, human health assessment and the protection of fish.In this investigation, we used Gobiocypris rarus which was the unique specie in China as test organism to study the bioaccumulation through dietary exposure and water exposure. In dietary exposure,50mg/kg and 100mg/kg of E2 and BPA food were used during the uptake phase and clean food was used duing the depration phase. In E2 water exposure, diluted 10 times of the saturated solution of E2 was used during the uptake phase and clean water was used duing the depration phase.Through out the experiments, chemical analysis methods were applied for the determination of E2 and BPA concentrations in water, food and fish at different time points. In the study we found:1、Chemical methods showed that the average recoveries of E2 and BPA in water,food and fish ranged from 75% to 110% and the relative standard deviations were less than 20%.2、Dietary exposure test:The amount of E2 accumulating in fish was not stabilized until the 14 days and 8 days respectively in low and high concentration (50mg/kg and 100mg/kg) test. In the depration phase, the amount of E2 in fish was eliminated quickly, and the half life is 0.5-1 day in Gobiocypris rarus. The amount of BPA were not stabilized until the 8 days both in high and low concentration test, and the half life is 0.1-0.5day in Gobiocypris rarus.3、Water exposure test:The amount of E2 accumulating in fish was not stabilized until the 4 days in the uptake phase, and was 4 times the amount of E2 through the dietary exposure. In the depration phase, the amount of E2 in Gobiocypris rarus was eliminated in 4 days, and the half life is 0.1-0.5day.4、On the basis of the experiment of BPA and E2 dietary exposure and water exposure, the calculated BMF was less than 1,and the BCF was less than 2000.Conclusion:1、The method of extraction, purification and concentration of the BPA and E2 in water, bait, excrement and fish body by the liquid-liquid extraction, gel permeation chromatography, solid phase extraction and LC-MS had good recoveries and relative standard deviations. It was completely satisfied for present experiments.2、E2 and BPA could be accumulated in Gobiocypris rarus through the water and dietary exposure. The amount of E2 and BPA accumulating in Gobiocypris rarus was connected with the way of exposure. The amount of E2 and BPA in Gobiocypris rarus through the dietary exposure was more than the amount of E2 and BPA in Gobiocypris rarus through the dietary exposure. Gobiocypris rarus had good abilities to metabolize the E2 and BPA. The amount of E2 and BPA in Gobiocypris rarus was eliminated for a short time.3、The time that the amount of E2 and BPA accumulating in fish reached equilibrium was related to exposure ways. Results showed that equilibrium time needed in dietary exposure was higher than that in water exposure.4、E2 and BPA had not biological magnification and bioaconcentration, and the bioaccumulation of E2 and BPA in the management level was irrelevant to exposure ways.