17α-甲基睾酮对稀有鮈鲫幼鱼性腺发育与血清卵黄蛋白原水平的影响

17α-甲基睾酮是一种人工合成雄激素,在水产养殖以及医药行业中广泛使用,其对鱼类的内分泌干扰效应研究工作相对较少.通过甲基睾酮对稀有鲫幼鱼的42天流水暴露,观察了其性腺发育和生物标记物变化.在500ng·L-1甲基睾酮暴露组中幼鱼生长受到抑制(p≤0.05),在50ng·L-1以上暴露组中性腺指数显著增加(p≤0.05),雄性个体比率明显升高.通过组织学观察发现,50ng·L-1以上浓度甲基睾酮暴露后卵巢组织切片中出现了精子细胞,且精子细胞数量随剂量的增加而增加.通过生物标记物卵黄蛋白原测定发现,在50ng·L-1以上浓度甲基睾酮暴露后,稀有鲫幼鱼血清中的卵黄蛋白原水平显著增加(p≤0.05).综合分析,17α-甲基睾酮主要表现出雄激素效应,而其在稀有鲫体内的代谢物则能够应激卵黄蛋白原,对稀有鲫幼鱼的最低可观察效应浓度(LOEC)为50ng·L-1.因此,仅依靠体内卵黄蛋白原应激单项指标不能准确判定化学品是否是环境类雌激素.     

Spatial and space-time scan statistics to detect low rate clusters of sex ratio

Whether general environmental exposures to endocrine disrupting chemicals (including pesticides and dioxin) might induce decreased sex ratios (male/female ratio at birth) is discussed. To address this issue, the authors looked for a space-time clustering test which could detect local areas of significantly low risk, assuming a Bernoulli distribution. As a matter of fact, if the endocrine disruptor hypothesis holds true, and if the sex ratio is a sentinel health event indicative of new reproductive hazards ascribed to environmental factors, then in a given region, either a cluster of low male/female ratio among newborn babies would be expected in the vicinity of polluting municipal solid waste incinerators (MSWIs) (supporting the dioxin hypothesis), or local clusters would be expected in some rural areas where large amounts of pesticides are sprayed. Among cluster detection tests, the spatial scan statistic has been widely used in various applications to scan for areas with high rates, and rarely (if ever) with low rates. Therefore, the goal of this paper was to check the properties of the scan statistics under a given scenario (Bernoulli distribution, search for clusters with low rates) and to assess its added value in addressing the sex ratio issue. This study took place in the Franche-Comté region (France), mainly rural, comprising three main MSWIs, among which only one had high dioxin emissions level in the past. The study population consisted of 192,490 boys and 182,588 girls born during the 1975–1999 period. On the whole, the authors conclude that: (i) spatial and space-time scan statistics provide attractive features to address the sex ratio issue; (ii) sex ratio is not markedly affected across space and does not provide a reliable screening measure for detecting reproductive hazards ascribed to environmental factors.     

Physiological Rearrangements in the Progeny of White Rats in the Zone of the Chernobyl Accident

Studies on six generations of white rats kept at the experimental station in Chernobyl showed that the dynamics of hormonal rearrangements and endocrine responses evoked by additional stress (hypokinesia) were generation- and sex-dependent. The male rats of the first five generations were characterized by hypercorticoidism, early involutional shifts, and decreased reactivity in response to hypokinesia. By the sixth and seventh generations, the hormonal profiles shifted toward an increase in the background level of sex hormones and their role in the response to hypokinesia. In female rats, the hormonal indices and reactivity changed less significantly.     

家蚕——新的内分泌干扰物筛选靶标

内分泌干扰物对人类及环境的影响日益严重,如何建立快速有效的筛选方法,从复杂的周围环境中鉴别出具有内分泌干扰活性的物质,指导人们尽量规避不必要的暴露风险,成了当前环境学家的重要任务。本文以鳞翅目昆虫的模式物种家蚕为对象,介绍了其内分泌系统组成及相关激素的作用,分析了作为内分泌干扰物筛选靶标的优势,阐述了候选的测试端点及依据,从理论和方法不同角度探讨了家蚕成为一种新的内分泌干扰物筛选靶标的可行性。     

淡水水生态基准方法学研究:繁殖/生殖毒性类化合物水生态基准探讨

繁殖/生殖毒性类化合物由于特殊的毒理作用模式(mode of action,MOA),通过影响生物繁衍影响到种群和群落,因此依靠基于急、慢性毒性测试终点和传统基准推导方法推导的水生态基准值并不能够为水生生物群落结构提供足够的保护。本文根据文献资料,分析了推导此类化合物水生态基准时的关键科学问题,包括繁殖/生殖毒性类化合物MOA,毒性数据类型,受试物种选择,以及不同生命阶段、多代毒性测试和测试终点的判别和选择。并用所收集的壬基酚数据,尝试推导了基于水生生物生殖毒性的水生态基准值。研究得出基于生殖毒性的壬基酚预测无观察效应浓度(PNEC)值为0.12μg·L-1,其数值比美国环境保护局根据传统基准方法推导的基准持续浓度(CCC)的6.59μg·L-1低了近50倍。因此,基于其繁殖毒性(包括产卵量、受精率、孵化率、多代效应以及种群变化等)的实验结果更适合用于具有繁殖/生殖毒性污染物水生态基准的推导。     

Research needs identified at the second PCB workshop in Brno,Czech Republic,May 7–11, 2002

More than 150 scientists from the Americas, Europe, and Asia met in Brno, Czech Republic, in May 2002 at the Second PCB Workshop, entitled “Recent Advances in the Environmental Toxicology and Health Effects of PCBs”. NIEHS/EPA-Superfund Basic Research Program, the Graduate Center for Toxicology at the University of Kentucky, and the Research Centre for Atmospheric and Environmental Chemistry and Ecotoxicology of Masaryk University, Brno, sponsored the Workshop. At six separate sessions (including posters) the origins, human residues and exposures, actions, biomarkers, risk and remediation issues relating to PCBs were discussed.     

Detecting points as developmental delay based on the life-history development and urosome deformity of the harpacticoid copepod, Tigriopus japonicus sensu lato, following exposure to benzo(a)pyrene

To identify ecotoxicological responses to an endocrine disrupter, benzo(a)pyrene, we examined the life-history of the harpacticoid copepod, Tigriopus japonicus sensu lato. Based on the life-history of copepods, survival rate of nauplii (NSR) and copepodites (CSR), copepodite emergence day (CED) and adult male emergence day (AMED), sex ratio (MER), brooding success rate (BSR), and first brooding day of adult females (FBD) were measured. Significant differences were observed in the survival and development of nauplii (NSR and CED) and sex ratio (MER) of exposed and non-exposed copepods. Moreover, high concentration of BaP can be lethal to copepodite and exhibited a delay of growth. In this study, the CED and AMED among ecotoxicological response based on life-history developments were delayed and the body characteristics decreased in response to exposure to benzo(a)pyrene. The dwarfism and urosome deformity of the T. japonicus s.l. was exhibited in response to chemical exposure. Specifically, the body characteristics and biomass of dwarf copepods that had been exposed to benzo(a)pyrene were 30% and 50% lower than the control group, respectively. The incidence of abnormal urosomes was divided into two types. The first deformity type was signs of shrinkage in the middle of the urosome or the entire urosome was narrower than those of the control organisms. In the second type, the anal somite and the distal side of the urosome had abnormally swelled. Taken together, the nauplii and copepodid development of T. japonicus s.l. can be used as a useful biomaker for detecting developmental delay based on their entire life-history. In addition, the urosome deformity was used a good potential monitoring tool invading various chemicals and environmental contamination into water system.     

The Effect of Estrogens,River Water,and Treated Wastewater on Vitellogenin Induction of Japanese Medaka1

Abstract: The objective of this study is to evaluate the effect of estrogens on fish endocrine disruption in river water and treated wastewater. Endogenous estrogen estrone (E1), 17β‐estradiol (E2), river water, and treated wastewater were used for exposure tests on male Japanese medaka. Vitellogenin induction in male medaka was regarded as the endpoint of endocrine disruption. The effective concentrations of E1 and E2 on vitellogenin induction in medaka were evaluated by breeding medaka for 14 days in tanks with various concentrations of E1 or E2. Vitellogenin induction increased with elapse of time during exposure, with higher estrogen concentrations causing greater vitellogenin induction. According to the test results, the lowest observed effect concentrations (LOECs) of E1 and E2 were estimated to be 31.6 and 5.0 ng/l, respectively; and the E2 equivalent (EEQ) LOEC value of E1 was 5.2 ng‐E2/l, derived by multiplying the relative potency of E1 by that of E2 as estimated in this study. In continuous exposure tests using river water or treated wastewater, the estrogenic activity, an index of total estrogenic potential measured by yeast screen assay and expressed as EEQ, varied widely during the exposure tests, and significant vitellogenin induction was observed after several days of high levels of estrogenic activity in water. Vitellogenin concentration tended to significantly increase if EEQ exceeded the level of 5 ng‐E2/l. The threshold value was substantially the same as the results for E1 and E2 exposure tests of medaka. Consequently, EEQ over 5 ng‐E2/l was revealed to have the potential to cause endocrine disruption of male medaka. As estrogenic activity exceeding 5 ng‐E2/l was observed in some rivers in Japan, total estrogenic potential needs to be further decreased at wastewater treatment plants to prevent fish endocrine disruption.     

环境内分泌干扰物的作用机理及其生物检测方法

环境污染物的内分泌干扰问题近年来引起了极大的关注,大量研究工作集中于对环境内分泌干扰物的作用机理及其生物检测方法的研究。在总结国内外相关研究的基础上,对环境内分泌干扰物的类型及其主要作用机理进行了概括总结;对环境内分泌干扰物的体外生物检测方法的最新研究进展给予了评述;并对环境内分泌干扰物检测技术在环境中的应用进行了探讨;指出有关环境内分泌干扰物作用机理研究的成果能直接导致新的生物检测方法的发展,丰富了环境内分泌干扰物的检测技术类型。     

丰水期沱江水系环境内分泌干扰物分布特征

采集丰水期沱江水系德阳至泸州水样,分析6种环境内分泌干扰物的含量和分布特征。主要检出双酚A、壬基酚,双酚A的平均浓度为3.93~198 ng/L,与国内外河流浓度相比处于中等水平;壬基酚平均浓度为5.23~150 ng/L,与国外河流水平相当,但低于目前已有报道的国内河流。沱江水系中双酚A、壬基酚的分布整体均呈现出北高南低,上游高于中游、下游,干流低于支流的特征。