Aliphatic and polycyclic aromatic hydrocarbons in the bottom sediments from Klaipėda Harbour,Lithuania (Baltic Sea)

A total of 22 bottom surface sediment samples were collected from Klaip?da Harbour, Lithuania (Baltic Sea). Sediment parameters, such as grain size and concentrations of total organic carbon, aliphatic hydrocarbons (ALHs) and polycyclic aromatic hydrocarbons (PAHs), were determined. Hydrocarbon contamination levels in the sediments were estimated based on classifications provided in the literature, and potential biological effects were assessed based on the effects range low–effects range median values of the Sediment Quality Guidelines and on the total toxic benzo(a)pyrene equivalent. The results demonstrated that concentrations of PAHs and total aliphatic hydrocarbons in the sediments varied between 1.6 and 5456?ng?g^?1 d.w. and 6.9 and 727?μg?g^?1 d.w., respectively. In most cases, the concentrations of ALHs and PAHs in the sediments indicated low to moderate levels of pollution and were not observed to have any significant adverse effects on living biota. To determine possible sources of hydrocarbons, hydrocarbon compositions were analysed, and ALHs’ and PAHs’ specific diagnostic ratios were calculated. According to the results, the Klaip?da Harbour bottom sediments were dominated by PAHs of pyrogenic origin, whereas the origin of ALHs was mixed, that is, anthropogenic with a biogenic (aquatic and terrestrial) input.     

Biodegradation of N,N-bis(carboxymethyl)-L-glutamate and its utilization as sole source of carbon,nitrogen, and energy by a Rhizobium radiobacter strain in seawater

Biodegradation of N,N-bis(carboxymethyl)-L-glutamate and its utilization by micro-organisms in marine environments were studied in Organization of Economic Development and Cooperation (OECD) screening tests and with pure bacterial cultures. Biodegradation in excess of 60% was achieved in closed bottle tests in less than 60 days, suggesting complete degradation. The bacterial strain isolated from marine sandy sediment and utilizing N,N-bis(carboxymethyl)-L-glutamate as sole source of carbon, nitrogen, and energy was identified as Rhizobium radiobacter. The strain was capable to mineralize N,N-bis(carboxymethyl)-L-glutamate in seawater and in synthetic media containing 0–60 g L^?1 sea salts. Growth and adaptation studies indicated that N-carboxymethyl-L-glutamate and L-glutamate are main metabolites.     

Improving simulations of sulfate aerosols during winter haze over Northern China: the impacts of heterogeneous oxidation by NO<Subscript>2</Subscript>

We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity (RH) were simulated well (mean biases are–0.2K and 2.7%, respectively), but wind speeds were overestimated (mean bias is 0.5 m?s^–1). At the Beijing station, sulfur dioxide (SO₂) concentrations were overpredicted and sulfate concentrations were largely underpredicted, which may result from uncertainties in SO₂ emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO₂ emissions and incorporating heterogeneous oxidation of dissolved SO₂ by nitrogen dioxide (NO₂) on sulfate formation during winter haze. The results suggest that doubling SO₂ emissions do not significantly affect sulfate concentrations, but adding heterogeneous oxidation of dissolved SO₂ by NO₂ substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO₂ to sulfate conversion in the HetS (heterogeneous oxidation by NO₂) case reduces SO₂ concentrations, it is still largely overestimated by the model, indicating the overestimations of SO₂ concentrations in the North China Plain (NCP) are mostly due to errors in SO₂ emission inventory.

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21世纪可替代脊椎动物进行生态毒性测试的方法：过去二十年的发展和现状综述

替代脊椎动物进行化学物质和污染物危害评估的方法已成为越来越重要的需求。现在首先要考虑的是当启动一个脊椎动物生态毒性测试,必须确保不必要的脊椎动物生物的使用尽可能最小化。对于一些监管目的,脊椎动物的使用对环境风险评估(ERA)已经被禁止,而在其他情况下生物测试的数量已经大大减少了,或者测试程序严格精简了。然而,想要获得能够完全替代脊椎动物提供环境危害数据的方法仍有很长的路要走。动物替代品的发展不仅仅是基于道德的考虑,也可以降低执行脊椎动物生态毒性测试的成本以及在某些情况下能够提供更好的信息旨在改进环境风险评估。本文集中综述了在过去的几十年里生态毒性评估替代方法所发生的重大的进展。
精选自Adam Lillicrap, Scott Belanger, Natalie Burden, David Du Pasquier, Michelle R. Embry, Marlies Halder, Mark A. Lampi, Lucy Lee, Teresa Norberg-King, Barnett A. Rattner, Kristin Schirmer, Paul Thomas. Alternative approaches to vertebrate ecotoxicity tests in the 21st century: a review of developments over the last two decades and current status. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2637–2646, November 2016. DOI: 10.1002/etc.3603
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3603/full