Chiral pharmaceuticals in the environment

Many pharmaceutical pollutants are chiral, existing in the environment as a single enantiomer or as mixtures of the two enantiomers. In spite of their similar physical and chemical properties, the different spatial configurations lead the enantiomers to have different interactions with enzymes, receptors or other chiral molecules, which can give diverse biological response. Consequently, biodegradation process and ecotoxicity tend to be enantioselective. Despite numerous ongoing research regarding analysis and monitorization of pharmaceutical ingredients in the environment, the fate and effects of single enantiomers of chiral pharmaceuticals (CP) in the environment are still largely unknown. There are only few chiral analytical methods to accurately measure the enantiomeric fraction (EF) in environmental matrices and during biodegradation processes. Furthermore, the ecotoxicity studies usually consider the enantiomeric pair as unique compound. We reviewed the current knowledge about CP in the environment, as well as the chiral analytical methods to determine the EF in environmental matrices. The degradation and removal processes of CP of important therapeutic classes, usually detected in the environment, and their toxicity to aquatic organisms were also reviewed. On the other hand, this review demonstrate that despite the great importance of the stereochemistry in pharmaceutical science, pharmacology and organic chemistry, this is normally neglected in environmental studies. Therefore, CP in the environment need much more attention from the scientific community, and more research within this subject is required.     

A Concentric Analysis of the Impact of Urbanization on the Threatened European Tree Frog in an Agricultural Landscape

Abstract:  Pond-breeding amphibians are affected by site-specific factors and regional and landscape-scale patterns of land use. Recent anthropogenic landscape modifications (drainage, agriculture intensification, larger road networks, and increased traffic) affect species by reducing the suitable habitat area and fragmenting remaining populations. Using a robust concentric approach based on permutation tests, we evaluated the impact of recent landscape changes on the presence of the endangered European tree frog ( Hyla arborea ) in wetlands. We analyzed the frequency of 1 traffic and 14 land-use indices at 20 circular ranges (from 100-m up to 2-km radii) around 76 ponds identified in western Switzerland. Urban areas and road surfaces had a strong adverse effect on tree frog presence even at relatively great distances (from 100 m up to 1 km). When traffic measurements were considered instead of road surfaces, the effect increased, suggesting a negative impact due to a vehicle-induced effect. Altogether, our results indicate that urbanization and traffic must be taken into account when pond creation is an option in conservation management plans, as is the case for the European tree frog in western Switzerland. We conclude that our easy-to-use and robust concentric method of analysis can successfully assist managers in identifying potential sites for pond creation, where probability of the presence of tree frogs is maximized.     

Microbial degradation of 17β -estradiol and 17α -ethinylestradiol followed by a validated HPLC-DAD method

This work aimed at studying the biodegradation of two estrogens, 17α -estradiol (E2) and 17β -ethinylestradiol (EE2), and their potential metabolism to estrone (E1) by microbial consortia. The biodegradation studies were followed by High Performance Liquid Chromatography–Diode Array Detector (HPLC–DAD) using a specifically developed and validated method. Biodegradation studies of the estrogens (E2 and EE2) were carried out with activated sludge (consortium A, CA) obtained from a Wastewater Treatment Plant (WWTP) and with a microbial consortium able to degrade recalcitrant compounds, namely fluorobenzene (consortium B, CB). E2 was more extensively degraded than EE2 by CA whereas CB was only able to degrade E2. The addition of acetate as a supplementary carbon source led to a faster biodegradation of E2 and EE2. E1 was detected as a metabolite only during the degradation of E2. The 16S rRNA gene sequence analyses of strains recovered from the degrading cultures revealed the presence of the genera Pseudomonas, Chryseobacterium and Alcaligenes. The genera Pseudomonas and Chryseobacterium were retrieved from cultures supplied with E2 and EE2, while the genus Alcaligenes was found in the presence of E2, suggesting that they might be involved in the degradation of these compounds.     

1999年委内瑞拉阿维拉山北坡入海型泥石流

委内瑞拉阿维拉山呈东一西走向，北坡濒临加勒比海．１９９９年１２月１６日，阿维拉山北坡２０多条沟谷暴发泥石流，使沿海的城镇、村庄、港口、公路及各种设施遭到毁灭性破坏，造成数万人死亡，直接经济损失超过刀亿美元．泥石流发生在森林植被良好的山区，具低频率和群发性特征，规模大，直接入海．分析这次泥石流灾害，对我国的防灾减灾工作具有启示意义．     

Distribution of endocrine disruptors in the Mondego River estuary, Portugal

Recent studies in the Mondego River estuary demonstrated signs of pollution in the area, but the nature of the contamination remains unexplored. Because there seems to be any studies in that zone checking for the simultaneous presence of xenoestrogenic endocrine disrupting compounds, either of animal (estradiol and estrone), vegetal (daidzein, genistein and biochanin A), pharmaceutical (17alpha-ethynylestradiol) or industrial (bisphenol A, 4-octylphenol, 4-nonylphenol) origins, the main objective of this study was to investigate their presence, in every year season and at eight points along the estuarine gradient. For this propose, water samples (2 L) were collected in high and low tides, preconcentrated in the Oasis HLB cartridges and cleaned in silica cartridges before their analysis by HPLC-DAD and GC-MS. The current data showed the absence of contamination by animal or pharmaceutical estrogens and by alkylphenols, but demonstrated the presence of high levels of phytoestrogens (up to 1.1 mug/L) and of bisphenol A (up to 880.0 ng/L). Because these two chemicals existed in high environmental concentrations in the most upstream sampling station, and taking in account that these pollutants may additively contribute to endocrine disruption, namely on fish, it was concluded that at least this particularly area of the Mondego estuary deserves continuous monitoring programmes.     

Occurrence of persistent organic pollutants in sediments and biota from Portugal versus European incidence: A critical overview

Persistent organic pollutants (POPs) are widespread compounds, such as organohalogenated compounds, polycyclic aromatic hydrocarbons (PAHs) and pesticides, which can be found in all types of environmental compartments. Their presence in the aquatic environment is a worldwide problem, with emphasis on sediments which act as depository and consequently as a source of hydrophobic, recalcitrant and harmful compounds. Besides, these pollutants might affect the reproduction and mortality of living organisms, diverging in their potential to bioaccumulate in tissues. The present paper aims to review the occurrence of POPs in sediments and biota from the coastal, estuarine and river areas of Portugal. The list of the studied compounds comprises organohalogenated compounds, PAHs, organometallic compounds, pesticides, sterols, fatty acids and pharmaceutical compounds. The contamination of sediments by various pollutants is presented, such as PAHs up to 7,350 ng g^?1 found in Sado estuary and polychlorinated biphenyls up to 62.2 ng g^?1 in the case of sediments collected in Ria de Aveiro. The occurrence of these persistent toxic substances in sediments demonstrates aquatic contamination from agricultural, industrial and urban discharges and the concern about the potential risks to aquatic organisms, wildlife and humans. In fact, several classes of POPs have also been found in biota, such as polychlorinated biphenyls up to 810.9 ng g^?1 in sentinel fish from the Douro River estuary and pesticides in bivalves from the Sado River estuary. The importance of further systematic research on sediments and biota is here highlighted to compare the contamination of these two reservoirs; to assess their spatial and temporal variation; and to determine other classes of POPs that were not investigated yet (e.g., industrial compounds, estrogens and many classes of pharmaceuticals).     

Enantioselective HPLC analysis and biodegradation of atenolol, metoprolol and fluoxetine

The accurate quantification of enantiomers is crucial for assessing the biodegradation of chiral pharmaceuticals in the environment. Methods to quantify enantiomers in environmental matrices are scarce. Here, we used an enantioselective method, high-performance liquid chromatography with fluorescence detection (HPLC-FD), to analyze two beta-blockers, metoprolol and atenolol, and the antidepressant fluoxetine in an activated sludge consortium from a wastewater treatment plant. The vancomycin-based chiral stationary phase was used under polar ionic mode to achieve the enantioseparation of target chiral pharmaceuticals in a single chromatographic run. The method was successfully validated over a concentration range of 20–800 ng/mL for each enantiomer of both beta-blockers and of 50–800 ng/mL for fluoxetine enantiomers. The limits of detection were between 5 and 20 ng/mL and the limits of quantification were between 20 and 50 ng/mL, for all enantiomers. The intra- and inter-batch precision was lower than 5.66 and 8.37 %, respectively. Accuracy values were between 103.03 and 117.92 %, and recovery rates were in the range of 88.48–116.62 %. Furthermore, the enantioselective biodegradation of atenolol, metoprolol and fluoxetine was followed during 15 days. The (S)-enantiomeric form of metoprolol was degraded at higher extents, whereas the degradation of atenolol and fluoxetine did not show enantioselectivity under the applied conditions.     

稻田土壤种子库研究进展

土壤种子库是指存在于土壤表面和土壤中全部存活种子的总和。稻田土壤种子库是地上杂草产生的根本来源。我国是一个水稻种植大国,目前关于稻田土壤种子库的研究还不够全面和深入。研究稻田土壤种子库对于防治稻田草害具有重要指导意义,同时也是种子库研究领域的一个重要补充。取样方法和取样时间是研究土壤种子库的关键所在。而萌发法是最常见的判定方法。关于稻田土壤种子库大小的结论相差很大,从103~105 m-2不等。稻田土壤种子库中的杂草主要有19科55种,一般的稻田可检出10科或20种左右。种子的垂直分布格局主要受耕作强度的影响。70%~80%甚至更多的杂草种子分布在0~10 cm。稻田土壤种子库由于萌发、捕食、衰老和种子散布等原因具有季节动态。轮作制度、耕作方式、不同施肥处理以及除草方式等对稻田土壤种子库有重要影响。连续多年的田间管理会使种子库的大小、分布和物种组成产生年际变化。目前,需要加强长期定位研究,扩大研究区域和研究内容,重点研究杂草种子的休眠萌发机制和种子命运研究,为杂草治理提供更准确的信息。     

Spatial distribution and quantification of endocrine-disrupting chemicals in Sado River estuary, Portugal

The important Portuguese Sado River estuary has never been investigated for the presence of potentially endocrine-disrupting chemicals (EDCs), such as natural estrogens (estradiol, estrone), pharmaceutical estrogens (17α-ethynylestradiol), phytoestrogens (daidzein, genistein and biochanin A), or industrial chemicals (4-octylphenol, 4-nonylphenol, and bisphenol A). Thus, the main objective of this study was to evaluate their presence at 13 sampling points distributed between both the industrial and the natural reserve areas of the estuary, zones 1 and 2, respectively. For that, water samples collected in summer and winter were processed by solid phase extraction and analyzed by high-performance liquid chromatography with photodiode array detection and gas chromatography–mass spectroscopy. Results showed that estrone, ethynylestradiol, all the aforementioned phytoestrogens as well as bisphenol A and 4-octylphenol were found in zone 1. In zone 2, neither estrogens nor 4-OP were found. However, in the same zone, daidzein (500 ng/L) and genistein (320 ng/L) attained their highest levels in summer, whereas biochanin A peaked in winter (170 ng/L). Furthermore, bisphenol A was also found in some areas of zone 2, but showed similar concentrations in both surveys (about 220 ng/L). This study demonstrated that the Sado River estuary had low EDCs levels, suggesting that the Sado’s high hydrodynamic activity may be involved in the dilution of local pollution. It was suggested that at the current levels of concentrations, all assayed EDCs are unlikely to individually cause endocrine disruption in local animals. However, under a continuous exposure scenario, an additive and/or synergistic action of the estrogenic chemicals load can not be excluded, and so, continuous monitoring is advisable.