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261.
建立了畜禽粪便和污水中金霉素(CTC)及其两种代谢物——差向金霉素(ECTC)和异金霉素(ICTC)的LC - MS/MS检测方法.粪便样品经Na2EDTA - Mcllvaine缓冲液(pH=4)分别提取3次,离心,收集上清液,过Waters的Oasis HLB固相萃取小柱净化、浓缩.用6mL0.01 mol·L-1草酸甲醇溶液洗脱,收集洗脱液,40℃水浴氮气吹至近干,甲醇定容至1 mL,过0.22μm滤膜,用LC- MS/MS测定.污水取100 mL经滤纸和0.65 μm纤维膜过滤后,加1 mL 5% Na2EDTA溶液,调节pH值至7.0,然后过预先用5 mL甲醇和10 mL Na2EDTrA- Mcllvaine缓冲液(pH=4)活化过的Waters Oasis HLB固相萃取小柱,净化、浓缩,后用6 mL0.01 mol·L-1草酸甲醇溶液洗脱,收集洗脱液,40℃水浴氮气吹至近干,甲醇定容至1 mL,过0.22 μm滤膜,上机测定.该方法在10~1 000μg·L-1之间呈线性相关,金霉素、差向金霉素和异金霉素的平均回收率分别为79.64% ~ 97.23%、75.34% ~ 98.37%和73.67% ~ 95.08%,日间偏差在1.78% ~6.18%,日内偏差在1.07%~6.28%.粪便样品和污水样品中的检测限分别为20μg·kg-1和10μg·L-1,符合作为检测方法的要求. 相似文献
262.
Nir Sapir Martin Wikelski Roni Avissar Ran Nathan 《Behavioral ecology and sociobiology》2011,65(7):1353-1365
Understanding departure decisions of migratory birds and the environmental factors affecting them is important for predicting
their distribution, abundance, and arrival times to breeding and wintering areas. In the past, methodological difficulties
to obtain fine-scale bird departure and meteorological data have limited testing the multi-scale effects of meteorology on
bird departure during migration. We investigated departure timing of European bee-eaters (Merops apiaster) staging in southern Israel, identified their departure flight mode (flapping or soaring) using radio telemetry, and measured
local meteorological conditions to study if bird departure was affected by these. Departure timing was examined using a timescale
analysis design. The conditions before, during, and after the time of departure were compared using timescales of 24 h, 6 h,
1 h, and 10 min and in relation to bird flight mode. At the between-days timescale, barometric pressure at departure time
was significantly lower compared with 2–1 day earlier, whereas temperature at departure was significantly higher compared
with 3–2 days earlier. Temperature at departure was also higher compared with 6 h and 3–2 h earlier. Tailwind assistance had
no significant effect at any timescale. Soaring birds departed at significantly higher temperature compared with flapping
birds. We suggest that bee-eater departure is tuned to the infrequent passage of warm atmospheric depressions at the between-days
timescale and with an increasing temperature trend within these days enabling the birds to use energetically cheap soaring
flight. We thus suggest that energetic considerations dictate the departure decisions of migrating European bee-eaters. 相似文献
263.
264.
Su HC Ying GG Tao R Zhang RQ Fogarty LR Kolpin DW 《Journal of environmental monitoring : JEM》2011,13(11):3229-3236
Antibiotics are still widely applied in animal husbandry to prevent diseases and used as feed additives to promote animal growth. This could result in antibiotic resistance to bacteria and antibiotic residues in animals. In this paper, Enterobacteriaceae isolated from four integrated fish farms in Zhongshan, South China were tested for antibiotic resistance, tetracycline resistance genes, sulfonamide resistance genes, and class 1 integrons. The Kirby-Bauer disk diffusion method and polymerase chain reaction (PCR) assays were carried out to test antibiotic susceptibility and resistance genes, respectively. Relatively high antibiotic resistance frequencies were found, especially for ampicillin (80%), tetracycline (52%), and trimethoprim (50%). Out of 203 Enterobacteriaceae isolates, 98.5% were resistant to one or more antibiotics tested. Multiple antibiotic resistance (MAR) was found highest in animal manures with a MAR index of 0.56. Tetracycline resistance genes (tet(A), tet(C)) and sulfonamide resistance genes (sul2) were detected in more than 50% of the isolates. The intI1 gene was found in 170 isolates (83.7%). Both classic and non-classic class 1 integrons were found. Four genes, aadA5, aadA22, dfr2, and dfrA17, were detected. To our knowledge, this is the first report for molecular characterization of antibiotic resistance genes in Enterobacteriaceae isolated from integrated fish farms in China and the first time that gene cassette array dfrA17-aadA5 has been detected in such fish farms. Results of this study indicated that fish farms may be a reservoir of highly diverse and abundant antibiotic resistant genes and gene cassettes. Integrons may play a key role in multiple antibiotic resistances posing potential health risks to the general public and aquaculture. 相似文献
265.
渤海湾浮游植物与环境因子关系的多元分析 总被引:11,自引:1,他引:10
2007年春季和夏季对渤海湾的浮游植物和环境因子进行调查,运用多元分析技术分析浮游植物在渤海湾的分布特征及其与环境因子之间的关系.调查期间共发现浮游植物26种,其中春季17种,夏季23种.春季浮游植物平均数量为115×104cells.m-3,显著高于夏季(3.1×104cells.m-3).应用主成分分析(PCA)浮游植物分布特征,结果表明,春季浮游植物主要分布于渤海的中北部,是硝酸盐含量较高的水域;夏季浮游植物分布于各个水域,但优势种主要分布于河口附近.运用冗余分析(RDA)探讨浮游植物分布与环境因子之间的关系,结果表明,影响渤海湾浮游植物分布的关键环境因子,春季是硝酸盐、亚硝酸盐和溶解性活性磷酸盐,夏季是氨氮和水温. 相似文献
266.
Wang Minghao Liu Xiaoyang Yang Bing Fei Yang Yu Jingjing An Ran Duan Lijie 《Environmental science and pollution research international》2021,28(23):29118-29130
Environmental Science and Pollution Research - Due to rapid urbanization, industrialization, agricultural development, and mining activities, soil heavy metal pollution has become a severe issue in... 相似文献
267.
Cao Tengrui Qu Aibin Li Zixuan Wang Wenjuan Liu Ran Wang Xue Nie Yaxiong Sun Suju Zhang Xiaolin Liu Xuehui 《Environmental science and pollution research international》2021,28(47):67053-67065
Environmental Science and Pollution Research - Some studies have shown that maternal perfluoroalkylated substances (PFAS) exposure may be associated with low birth weight (LBW) of offspring. We... 相似文献
268.
This paper reports on the potential to apply the choice experiment method to understand the public's preferences for solid waste management programmes in Macao. A random sample survey of 260 respondents in Macao was conducted during the summer in 2004. The survey data was analysed using conditional multinomial logit models. The study results indicate that Macao residents prefer: (1) waste segregation and recycling at source; (2) noise reduction during waste collection and transportation and (3) lower garbage fees. The study concludes that choice experiment is a reliable tool in the analysis of respondents' preferences for developing a suitable solid waste management programme in Macao. 相似文献
269.
Guoqing Wang Jianyun Zhang Junliang Jin Josh Weinberg Zhenxin Bao Cuishan Liu Yanli Liu Xiaolin Yan Xiaomeng Song Ran Zhai 《Mitigation and Adaptation Strategies for Global Change》2017,22(1):67-83
Climate change is a global environmental issue, which is challenging water resources management and practices. This study investigates the impact of climate change on water resources of the Yellow River basin, a major grain-producing area in China, and provides recommendations on strategies to increase adaptive capacity and resilience in the basin region. Results show that the recorded stream flows of the Yellow River declined from 1951 to 2010 and have decreased significantly in the middle and lower reaches. The variable infiltration capacity (VIC) model performs well as a tool to simulate monthly discharge of both the tributary catchments and the whole Yellow River basin. Temperature across the Yellow River basin over 2021–2050 is expected to continue to rise with an average rates of approximately 0.039–0.056 °C/annum. The average annual precipitation in the basin is projected to increase by 1.28–3.29 % compared with the 1991–2010 baseline. Runoff during 2021–2050 is projected to decrease by 0.53–9.67 % relative to 1991–2010 with high decadal and spatial variability. This is likely due to the model’s projections of a significant rise in temperature and changes in precipitation patterns. Climate change will likely aggravate the severity and frequency of both water shortages and flooding in the basin region. It is therefore essential to devote sufficient attention on structural and non-structural measures for the Yellow River basin to cope with climate change. At the global level, strategies to increase adaptive capacity and build resilience to climate change focus on public education to improve awareness of climate risks, implementing the integrated water resources management and planning based on impact assessments. 相似文献
270.