纳米铜颗粒的种间毒性关系

纳米颗粒的种间毒性关系尚无明确结论,因此很难判断纳米颗粒对未进行毒性测试的物种的风险如何。本文作者将5种水蚤(Daphnia magna, Daphnia pulex, Daphnia galeata, Ceriodaphnia dubia, Chydorus sphaericus)暴露于4种不同粒径的纳米铜颗粒(CuNPs)和1种亚微米铜颗粒的悬浊液中,考察物种的形态特征与CuNPs急性毒性的关系。结果显示,杆状的CuNPs比球状的CuNPs毒性更低。纳米铜颗粒与溶出铜离子均对CuNPs的毒性有贡献,其中,当新生蚤的体长、体表面积和身体体积更小时,5种悬浊液中颗粒的毒性更大。5种蚤的身体体积与5种CuNPs的毒性显著相关(r_adj²>0.51, p < 0.001),78-nm CuNPs与蚤身体体积的相关性最好 (r_adj²?=?0.95, p < 0.001)。这个研究可以为纳米颗粒对有相似外形特征的物种进行毒性种间外推提供线索。
精选自Lan Song, Martina G. Vijver, Geert R. de Snoo and Willie J.G.M. Peijnenburg. Assessing toxicity of copper nanoparticles across five cladoceran species. Environmental Toxicology and Chemistry: Volume 34, Issue 8, pages 1744–1750, August 2015. DOI: 10.1002/etc.3000
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3000/full     

Assessment of Water Quality in a Border Region Between the Atlantic Forest and an Urbanised Area in Rio de Janeiro,Brazil

The preservation of water resources is one of the goals of the designation of parks that act as natural reservoirs. In order to assess the impact of the presence of humans in an environmental preservation area bordering urban areas, the presence of four pathogenic enteric viruses [group A rotavirus (RV-A), norovirus (NoV), human adenoviruses (HAdV), and hepatitis A virus (HAV)], as well as the physico-chemical parameters, and Escherichia coli levels were assessed in riverine water samples. From June 2008 to May 2009, monthly monitoring was performed along the Engenho Novo River. RV-A, NoV, and HAdV were observed in 29 % (31/108) of the water samples, with concentrations of up to 10³ genome copies/liter. The natural occurrence of infectious HAdV was demonstrated by Integrated Cell Culture-PCR (ICC-PCR). This study confirms the suitability of using the detection of fecal-oral transmitted viruses as a marker of human fecal contamination in water matrices and indicates the spread of pathogenic viruses occurring in an alleged area of environmental protection.     

Now you see me,now you don’t: iridescence increases the efficacy of lizard chromatic signals

The selective forces imposed by primary receivers and unintended eavesdroppers of animal signals often act in opposite directions, constraining the development of conspicuous coloration. Because iridescent colours change their chromatic properties with viewer angle, iridescence offers a potential mechanism to relax this trade-off when the relevant observers involved in the evolution of signal design adopt different viewer geometries. We used reflectance spectrophotometry and visual modelling to test if the striking blue head coloration of males of the lizard Lacerta schreibeiri (1) is iridescent and (2) is more conspicuous when viewed from the perspective of conspecifics than from that of the main predators of adult L. schreibeiri (raptors). We demonstrate that the blue heads of L. schreiberi show angle-dependent changes in their chromatic properties. This variation allows the blue heads to be relatively conspicuous to conspecific viewers located in the same horizontal plane as the sender, while simultaneously being relatively cryptic to birds that see it from above. This study is the first to suggest the use of angle-dependent chromatic signals in lizards, and provides the first evidence of the adaptive function of iridescent coloration based on its detectability to different observers.     

Using Soil and Water Conservation Contests for Extension: Experiences from the Bolivian Mountain Valleys

Soil and water conservation (SWC) contests among farmer groups were organized in five rural villages in the Bolivian mountain valleys. The contests were aimed at quickly achieving widespread sustainable results. This article analyzes the effectiveness of these contests as an extension tool. Mixed results were obtained. In three villages, participation rates in the SWC activities introduced in the contests were still high even 2 years after project withdrawal. These were all villages where a solid foundation for sustainable development had been laid before the contests were held. Two years later, most families were still involved in maintenance of the SWC practices introduced in the contests, and many farmers had started to experiment with different soil management practices. However, replications of these SWC practices were not widespread, Conservation Leaders did not continue with their training activities, and the quality of maintenance of the practices was often not satisfactory. In order to become a more effective extension tool and achieve widespread impact, SWC contests must receive continued support by a catalyst agency. Moreover, other SWC contests should also be organized in which practices are not predefined. Given that SWC contests are a low-budget extension tool, local municipalities could become more actively involved.     

A molecular fingerprint technique to detect pollution-related changes in river cyanobacterial diversity

Humans now have a strong influence on almost every major aquatic ecosystem, and our activities have dramatically altered the quality of receiving waters worldwide. Thus, there is a continuous need to develop and apply novel and effective technologies to detect, manage, and correct human-induced degradation of aquatic systems. In the present work, we evaluated the molecular approach using polymerase chain reaction (PCR)-temperature gradient gel electrophoresis (TGGE) to measure changes in cyanobacterial diversity along a pollution gradient in a river and compared it with that of using microscopic observations of field-fixed and cultured samples. The different 16S rDNA genes present in the cyanobacterial community of each sampling point of the river were separated by TGGE, giving a characteristic pattern of bands for each site. This pattern represents a "fingerprint" of the community, allowing direct comparisons of the different samples. The TGGE results revealed that the structure of the cyanobacterial community differed along the pollution gradient of the river. Microscopic and molecular approaches showed that cyanobacterial diversity decreased in a downstream direction. Similar results were obtained by the two methods, as indicated by the high correlation between them. We suggest PCR-TGGE could be a useful and rapidly applied technique for the routine analysis of changes in cyanobacterial diversity in response to pollution, which would allow us to monitor rivers in surveillance networks of watercourse quality.     

1,2,4-trichlorobenzene marine risk assessment with special emphasis on the Osparcom region North Sea

A risk assessment on 1,2,4-trichlorobenzene was carried out specifically for the marine environment according to the methodology laid down in the EU Risk Assessment Regulation 1488/94 and the Guidance Documents of the EU Existing Substances Regulation 793/93. The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by comparing the predicted environmental concentration (PEC) with the predicted no-effect concentrations (PNEC) for the marine aquatic environment. A PNECwater) value of 0.3 microg/l and a PNECsed value of 38 microg/kgdw were derived from the results of toxicological studies in organisms representing three trophic levels, i.e. aquatic plants, invertebrates and fish. Based on monitoring data two situations are distinguished: a typical case and a worst case with a PECwater of <0.047 and 0.1 microg/l, respectively, and a PECsed of 40 and 90 microg/kgdw, respectively. The calculated PEC/PNEC ratios were 0.16 and 0.3 for water and 1 and 2.4 for sediment, respectively. It was concluded that no risks are expected for aquatic organisms. Based on the combination of worst-case assumptions risks to benthic organisms could not be fully excluded, but since all open uses of 1,2,4-trichlorobenzene will be ended following the EU risk assessment outcome of 2001 any potential risk is expected to be reduced accordingly. 1,2,4-trichlorobenzene is not considered toxic according to the EU criteria and the available data on persistence of 1,2,4-trichlorobenzene indicate a half-life in water of a few days and a significant biodegradation potential. The bioaccumulation potential is low to moderate with most BCF ratios for fish ranging from 600 to 1400 and one highest of 2020. Based on an extensive evaluation of persistence, biodegradation and bioaccumulation data it is concluded that 1,2,4-trichlorobenzene is not a PBT, since it does not fulfill any of the EU criteria. Biomagnification in the food chain is not expected due to the relatively high elimination rate constants.     

Hydrodechlorination of dichlorobiphenyls over Ni-Mo/Al2O3 catalysts prepared by spray-drying method

The hydrodechlorination (HDCl) process of 2,3-, 2,4- and 2,5-dichlorobiphenyls was studied over a sulphided Ni-Mo/Al(2)O(3) catalyst in a stirred autoclave at a hydrogen pressure of 3 MPa. The catalysts were prepared by spray-drying. They were characterized by N(2) adsorption, thermogravimetry and scanning electron microscopy with X-ray microanalysis. The reaction temperature of the catalytic HDCl process was varied in the range of 230-290 degrees C. Polychlorinated biphenyls (PCBs) free transformer oil was used as reaction medium. The HDCl degree of dichlorobiphenyl isomers was in the range of 82-93%. The efficiency in the chlorine removal was found to be related to the position of the substituted chlorine atom and decreased as follows 2,4-dichlorobiphenyl approximately 2,5-dichlorobiphenyl>2,3-dichlorobiphenyl. For comparison, the HDCl process of 2,3-dichlorobiphenyl (2,3-PCB) without catalyst was also studied. The chlorine removal was 85% for the catalytic HDCl of 2,3-PCB whereas non-catalytic process led only to 16% of dechlorination in the same operating conditions, i.e. at 290 degrees C after 120 min. Monodichlorobiphenyls were not detected in the reaction products. The data for both catalytic and non-catalytic conversion of 2,3-PCB fit to a first-order model. Kinetic constants and the activation energy of the overall HDCl reaction of 2,3-PCB to biphenyl were evaluated. Compared to non-catalytic process, a nearly threefold decrease in the activation energy was observed in the presence of Ni-Mo/Al(2)O(3) catalyst prepared by spray-drying (48 kJ mol(-1) vs. 124 kJ mol(-1)).     

Levels and trends of brominated flame retardants in the Arctic

Polybrominated diphenyl ethers (PBDEs) containing two to seven bromines are ubiquitous in Arctic biotic and abiotic samples (from zooplankton to polar bears (Ursus maritimus) and humans; air, soil, sediments). The fully brominated decabromodiphenyl ether (BDE-209), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA) and polybrominated biphenyls (PBBs) are also present in biotic and abiotic samples. Spatial trends of PBDEs and HBCD in top predators are similar to those seen for polychlorinated biphenyls (PCBs) and indicate western Europe and eastern North America as source regions. Concentrations of tetra- to heptaBDEs have increased significantly in North American and Greenlandic Arctic biota and in Greenland freshwater sediments paralleling trends seen further south. For BDE-209, increasing concentrations in Greenlandic peregrine falcons (Falco peregrinus) and in dated lake sediment cores in the Canadian Arctic have been seen during the 1990s. BDE-47, -99, -100 and -153 are observed to biomagnify in Arctic food webs. summation operatorPBDE concentrations in Arctic samples are lower than in similar sample types from more southerly regions and are one or more orders of magnitude lower than summation operatorPCB concentrations except for some levels for air. Air and harbor sediment results for PBDEs indicate that there are local sources near highly populated areas within the Arctic. Findings of PBBs on moss and TBBPA on an air filter, and that both are found in biota at high trophic levels indicates that these compounds may also reach the Arctic by long-range atmospheric transport. Based on the evidence of their presence in the Arctic and indications that most if not all are undergoing long-range transport, these brominated flame retardants (BFRs) have characteristics that qualify them as POPs according to the Stockholm Convention.