Endocrine modulation, inhibition of ovarian development and hepatic alterations in rainbow trout exposed to polluted river water

Under laboratory conditions, female rainbow trout were exposed to graded concentrations of water from the River Lambro, a polluted tributary of the River Po, and to the effluent of a large wastewater treatment plant which flows into the River Lambro. In field exposures, trout were held in cages in the River Po upstream and downstream from the confluence of the River Lambro. After 10-day (laboratory) and 30-day (laboratory and field) exposures, trout were examined for several chemical, biochemical and histological endpoints. The results indicated that exposure to complex mixtures of chemicals, including estrogen receptor agonists, aryl-hydrocarbon receptor agonists, and probably antiandrogens, had occurred. Exposure altered the plasma levels of 17β-estradiol and testosterone, and some treatments also enhanced the activity of hepatic ethoxyresorufin O-deethylase. Gonadal histology showed varying levels of degenerative processes characterised by oocyte atresia, haemorrhages, melano-macrophage centres (MMCs), and oogonia proliferation. Liver histology showed less severe effects.     

利用哺乳动物测试系统识别非哺乳类群中雌激素化学物质的科学基础评估

美国环境保护部负责评估超过10 000种化学物质的内分泌活动,而合理的实现评估不能仅仅利用体内化验。因此,使用以特定的内分泌系统为目标测定的体外高通量(HTP)数据提出了化学物质体内化验优先原则。最近聚焦于潜在雌激素化学物质—特别是关于能够激活雌激素受体α(ERα)的化学物质的研究工作大致证实了该方法的可行性。然而,该方法存在一个主要的不确定性,那就是基于哺乳动物(主要是人类)的HTP ER化验的优先级是否能够准确地反映chemical-ERα在非哺乳类物种中潜在的相互作用。这里我们对以下几方面进行了全面分析,包括基于ERs结构属性、体外绑定和ERα反式激活数据的相关信息研究chemical-ERα交互作用的跨物种相似性,以及一系列化学物质对体内雌激素信号通路的影响。总的来说,这种综合分析表明,在哺乳动物系统中具有中度到高度雌激素效能的化学物质在非哺乳类脊椎动物中同样是优先级的化学物质。然而,由于缺乏对可能的ERαorthologues的生物作用的了解,优先级方法在多大程度上能够适用于无脊椎动物是不确定的。进一步比较分析鱼类和爬行动物的体外数据表明基于哺乳类的试验可能不会有效地获取在所有脊椎动物门类中ERα与低亲和力的化学物质的交互作用。
精选自Gerald T. Ankley, Carlie A. LaLone, L. Earl Gray, Daniel L. Villeneuve, Michael W. Hornung. Evaluation of the Scientific Underpinnings for Identifying Estrogenic Chemicals in Non-Mammalian Taxa using Mammalian Test Systems. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2806–2816, November 2016. DOI: 10.1002/etc.3456
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3456/full
     

Dissolved organic carbon from sewage sludge and manure can affect estrogen sorption and mineralization in soils

In this study, effects of sewage sludge and manure borne dissolved organic carbon (DOC) on 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) sorption and mineralization processes were investigated in three agricultural soils. Batch equilibrium techniques and equilibrium dialysis methods were used to determine sorption mechanisms between DOC, estrogens and the soil solid phase. It was found that that the presence of organic waste borne DOC decreased estrogen sorption in soils which seems to be controlled by DOC/estrogen complexes in solution and by exchange processes between organic waste derived and soil borne DOC. Incubation studies performed with ¹⁴C-estrogens showed that DOC addition decreased estrogen mineralization, probably due to reduced bioavailability of estrogens associated with DOC. This increased persistence combined with higher mobility could increase the risk of estrogen transport to ground and surface waters.     

Effects of estrogen exposure in mussels, Mytilus edulis, at different stages of gametogenesis

Mytilus edulis were exposed to 17β-estradiol (E2) and the synthetic estrogens ethinyl estradiol (EE2) and estradiol benzoate (EB) for 10 days. Two exposures were performed to determine their effect on vitellogenin (VTG) and estrogen receptor 2 (ER2) mRNA expression at different stages of the reproductive cycle. Significant natural variation was not observed in VTG mRNA expression, though ER2 mRNA expression displayed significantly lower values during January, February and July compared with other times of the year. A significant increase in VTG and ER2 mRNA expression was observed in mussels exposed to estrogens at the early stage of gametogenesis. In contrast, mature mussels displayed no statistically significant change in the VTG or ER2 mRNA expression. The data presented suggests that the reproductive physiology of molluscs, in terms of VTG and ER2 mRNA expression, may be susceptible to damage by environmental estrogens at certain points in their gametogenesis process.     

Monitoring of natural and synthetic hormones in a polluted river

Natural (estradiol, estrone, testosterone, estriol) and synthetic hormones (ethinylestradiol) are constantly excreted into the environment from human and animal sources but little is known of their transport. The purpose of this study was to determine how far along a 100 km river course that hormones could be detected after contamination with sewage effluent or fishpond effluent. Fourteen sites in the Lower Jordan River drainage were sampled (two sites above the sewage effluent contamination, eight sites below the contamination and four tributaries) before and after the dry season of 2002 (Spring and Fall). Samples were tested for testosterone, estrogen (estrone and estradiol combined), estriol, ethinylestradiol, ammonia and fecal coli. It was found that the fecal coli count dropped exponentially (from 250,000 to 60/100 ml3) and the ammonia dropped from 15 to less than 1mg/l over the initial 25 km stretch. Over the same stretch, the hormone values declined by half from their maximum values for testosterone (3.3 ng/l), estriol (8.8 ng/l), ethinylestradiol (6.1 ng/l), and estrogen (4.9 ng/l). From 67 to 100 km mark, testosterone (4.8 ng/l) and estrogen (2.4 ng/l) were still elevated while ethinylestradiol and estriol were >or=1.5 ng/l. The high level of testosterone and estrogen between 67 and 100 km marks was probably due to major discharge from fishponds between 23 and 27 km marks. Levels of ethinylestradiol above 1 ng/l, a level which can affect fish, was seen in 70% (12/16) of the samples tested. The data suggest that hormones in readily measured quantities can be transported considerable distances from the source of pollution.