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551.
采用半静水式实验方法,研究Pb~(2+)暴露30 d对中华大蟾蜍(Bufo bufo gargarizans Cantor)生理状态和耳后腺分泌蟾蜍甾烯水平的影响。结果表明,随Pb~(2+)浓度(0.68~5.46 mg·L~(-1))升高,蜕皮和自发活动减少,存活率下降。进一步采用液相-质谱检测技术发现,0.68 mg·L~(-1)Pb~(2+)暴露下,10种蟾蜍甾烯水平出现1.5倍以上变化。5.46 mg·L~(-1)Pb~(2+)暴露下,17种蟾蜍甾烯水平发生下调(1.5倍),其中bufarenogin水平显著下降(P0.05),其他物质水平与对照组无显著性差异。这说明Pb~(2+)暴露对蟾蜍耳后腺中蟾蜍甾烯物质具有潜在影响。 相似文献
552.
Characteristics of atmospheric non-methane hydrocarbons during haze episode in Beijing, China 总被引:1,自引:0,他引:1
Songjun Guo Jihua Tan Jingchun Duan Yongliang Ma Fumo Yang Kebin He Jimin Hao 《Environmental monitoring and assessment》2012,184(12):7235-7246
This study firstly focused on non-methane hydrocarbons (NMHCs) during three successive days with haze episode (16–18 August 2006) in Beijing. Concentrations of alkanes, alkenes, aromatic hydrocarbons, and ethyne all peaked at traffic rush hour, implying vehicular emission; and alkanes also peaked at non-traffic rush hour in the daytime, implying additional source. Especially, alkanes and aromatics clearly showed higher levels in the nighttime than that in the daytime, implying their active photochemical reactions in the daytime. Correlation coefficients (R 2) showed that propane, n-butane, i-butane, ethene, propene, and benzene correlated with ethyne (R 2?=?0.61–0.66), suggesting that their main source is vehicular emission; 2-methylpentane and n-hexane correlated with i-pentane (R 2?=?0.61–0.64), suggesting that gasoline evaporation is their main source; and ethylbezene, m-/p-xylene, and o-xylene correlated with toluene (R 2?=?0.60–0.79), suggesting that their main source is similar to that of toluene (e.g., solvent usage). The R 2 of ethyne, i-pentane, and toluene with total NMHCs were 0.58, 0.76, and 0.60, respectively, indicating that ambient hydrocarbons are associated with vehicular emission, gasoline evaporation, and solvent usage. The sources of other hydrocarbons (e.g., ethane) might be natural gas leakage, biogenic emission, or long-range transport of air pollutants. Measured higher mean B/T ratio (0.78?±?0.27) was caused by the more intensive photochemical activity of toluene than benzene, still indicating the dominant emission from vehicles. 相似文献
553.
Xiaoshan Zhou Wan Wei Xiaoran Duan Hui Zhang Xiaolei Feng Tuanwei Wang 《Journal of environmental science and health. Part. B》2020,55(6):525-529
AbstractTelomere length was found to be associated with omethoate exposure and polymorphisms in certain genes among occupational workers. However, whether the polymorphisms in telomere-binding protein genes influence telomere length remains unclear. To explore the correlation between telomere length and polymorphisms in telomere-binding protein genes, telomere length in peripheral blood leukocytes was determined by real-time quantitative polymerase chain reaction in 180 omethoate-exposed workers and 115 healthy controls. Polymorphisms in 10 pairs of alleles were detected using flight mass spectrometry or polymerase chain reaction–restriction fragment length polymorphism technique. The results showed that individuals with GG genotype in TRF1 rs3863242 had longer telomere lengths than those with AG?+?AA genotype in the control group (p?=?0.005). The multiple regression analysis suggested that both omethoate exposure (b?=?0.526, p?<?0.001) and TRF1 rs3863242 GG (b?=?0.220, p?=?0.002) were related to a longer telomere length. In conclusion, GG genotype in TRF1 rs3863242 is linked to prolongation of telomere length, and individuals with GG genotype are recommended to strengthen health protection in a Chinese occupational omethoate-exposed population. 相似文献
554.
某光热电站熔盐蒸发器入口侧管板封口焊缝发生泄漏,通过表面检测和观察,发现裂纹是从封口焊缝根部发展,并从根部向外扩展的。根据裂纹扩展方向和运行数据进行综合分析认为,熔盐蒸发器在未正确操作下导致在极短时间内管板下部表面升温过快,造成封口焊缝局部热应力过大。在焊缝残余应力、工作应力和热应力共同作用下,管板下部封口焊缝根部产生裂纹并扩展至焊缝表面,形成贯穿性裂纹,造成蒸发器管板泄漏。 相似文献
555.
Min Min Lin Chen Duan Xuejun Jin Zhifeng Zhang Luocheng 《Environment, Development and Sustainability》2021,23(9):12791-12813
Environment, Development and Sustainability - Poverty is a common problem faced by various social and economic forms. Eliminating poverty is a major issue of common concern and research all over... 相似文献
556.
从"阳光体育"助推学校体育管理变革出发,借鉴和运用利益相关者理论,分析我国学校体育管理变革的逻辑基础以及划分出不同的利益相关者,指出学校体育管理变革实质上就是各利益相关者之间利益博弈或行为协作的制度变迁过程,其结果是各利益相关者对学校体育资源及其附属品的再分配,其中利益冲突是变革的核心内容,而造成利益冲突的原因是多方面的。走向利益均衡是学校体育管理变革的基本价值取向。 相似文献
557.
Feng Li Xiang-yun Zeng Yun-jun Yu Chang-hua Wu Ge Mai Wei-wei Song Yan-mao Wen Zhi-peng Duan Jia-yu Yang 《Environmental monitoring and assessment》2014,186(8):4935-4946
Acid volatile sulfide (AVS) has been regarded as an important factor controlling metal bioavailability in anoxic sediments, but its effect on metal accumulation under natural conditions is poorly understood. Here, a field study of the influence of AVS on metal accumulation by Limnodrilus sp. in a heavily polluted river is provided. Most of the study area was subject to anaerobic and strongly reducing conditions, and the concentration of trace metals in surface sediments was high, as were the concentration of AVS and simultaneously extracted metals (SEM; average AVS?=?20.3 μmol g?1, average ∑SEM5?=?9.42 μmol g?1; ∑SEM5 refers to the sum of SEMCd, SEMCu, SEMPb, SEMNi, and SEMZn). Only a few species and small quantities of benthic invertebrates were found, and Limnodrilus sp. was dominant. There was no correlation between trace metal accumulation and (SEM-AVS), and in stations where (SEM-AVS) <0, the absolute value of bioaccumulation was high (average ∑BIO5?=?4.07 μmol g?1; ∑BIO5 refers to the sum of BIOCd, BIOCu, BIOPb, BIONi, and BIOZn), indicating that there was no relationship between (SEM–AVS) and metal accumulation in Limnodrilus sp. This was likely because Limnodrilus sp. ingest sediment particles as their main food source, so pore water metals play a minor role in their bioaccumulation (BIO) of materials. However, ∑BIO5 was significantly correlated with ∑SEM5 (r?=?0.795, p?<?0.01), revealing that the large number of sulfide-bound metals (SEM) in sediments may play an important role in metal accumulation in Limnodrilus sp., which can assimilate sulfide-associated metals by the help of the digestive fluids in the digestive systems. 相似文献
558.
Duan Huiming Luo Xilin 《Environmental science and pollution research international》2020,27(35):43884-43905
Environmental Science and Pollution Research - Energy saving and emission reduction are the most concerned issues in the world. Objective and accurate prediction of carbon emissions can provide... 相似文献
559.
Environmental significance of biogenic elements in surface sediments of the Changjiang Estuary and its adjacent areas 总被引:5,自引:0,他引:5
Biogenic elements and six phosphorus(P) fractions in surface sediments from the Changjiang Estuary and adjacent waters were determined to investigate the governing factors of these elements, and further to discuss their potential uses as paleo-environment proxies and risks of P release from sediment. Total organic carbon(TOC) and leachable organic P(Lea-OP) showed high concentrations in the estuary, Zhejiang coast and ofshore upwelling area. They came from both the Changjiang River and marine biological input.Biogenic silicon(BSi) exhibited a high concentration band between 123 and 124°E. BSi mainly came from diatom production and its concentration in the inshore area was diluted by river sediment. Total nitrogen(TN) was primarily of marine biogenic origin. Seaward decreasing trends of Fe-bound P and Al-bound P revealed their terrestrial origins. Influenced by old Huanghe sediment delivered by the Jiangsu coastal current, the maximum concentration of detrital P(Det-P) was observed in the area north of the estuary. Similar high concentrations of carbonate fluorapatite(CFA-P) and CaCO3 in the southern study area suggested marine calcium-organism sources of CFA-P. TOC, TN and non-apatite P were enriched in fine sediment, and Det-P partially exhibited coarse-grain enrichment, but BSi had no correlation with sediment grain size. Diferent sources and governing factors made biogenic elements and P species have distinct potential uses in indicating environmental conditions. Transferable P accounted for 14%-46% of total P. In an aerobic environment,there was low risk of P release from sediment, attributed to excess Fe oxides in sediments. 相似文献
560.
本文以畜禽养殖较为集中、污染问题较为突出的辽河源头区为研究区域,通过流域内畜禽污染物排放方式,污染物排放总量,总结流域内畜禽养殖污染特点,在次基础上提出切实可行的畜禽污染防治对策,为相关政策的制定提供依据。 相似文献