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451.
Earthworm cytochrome P450 determination and application as a biomarker for diagnosing PAH exposure 总被引:1,自引:0,他引:1
Zhang W Song YF Gong P Sun TH Zhou QX Liu M 《Journal of environmental monitoring : JEM》2006,8(9):963-967
We developed a new microsome purification method and used the Omura and Sato method to measure the total content of cytochrome (Cyt) P450 in earthworm (Eisenia fetida) microsomes. In method development, two different pretreatments, i.e. solubilization or manual separation were used to purify worm microsomes. Solubilization was more effective than manual separation and difference spectra showed a peak at 450 +/- 1 nm in microsomes received solubilization pretreatment. We conducted a 48 h contact test by exposing worms on pyrene (Py) and benzo[a]pyrene (BaP) spiked filter paper. A dose-response relationship was established between total P450 content and the concentration of Py or BaP ranging from 10(-6) mg mL(-1) to 10(-2) mg mL(-1). Results show that total Cyt P450 content in earthworms is a promising biomarker for diagnosing PAHs exposure at sublethal dose ranges. 相似文献
452.
湖南蔡家塘森林小流域氮和硫的输入输出特征 总被引:5,自引:3,他引:2
以湖南韶山蔡家塘小流域2001~2003年的监测数据为基础,对森林在酸沉降作用下无机氮(NH 4,NO-3)和硫输入、输出的月均通量进行了研究.结果表明,总氮的年输入通量为24~28 kg·hm-2·a-1,主要以NH 4形式(占总输入氮的62%~67%)输入该森林生态系统;年氮输出通量为2~3kg·hm-2·a-1,主要以NO-3形式(占总输出N的83%~98%)输出该森林生态系统.韶山森林年无机氮的滞留量达到22~26kg·hm-2·a-1,其中NH 4占到总氮净截留量的68%~72%.硫的截留量为13~21 kg·hm-2·a-1.高氮沉降导致了一部分氮的输出,但是输出氮仅占到输入氮的8%~9%.有超过90%的氮被生态系统截留.由此可以推断,韶山森林尽管有高氮输入,但是生态系统远没有达到氮饱和状态. 相似文献
453.
454.
Ran Gong Ligang Xu Deguan Wang Hongyi Li Jin Xu 《Environmental Modeling and Assessment》2016,21(5):643-655
Urban lakes are typically characterized by fragile ecological capacities and complex management of their hydrospheric ecosystems. The aims of this study are to establish a reliable hydrodynamic-water quality model for an urban lake, to investigate the responses of water quality to different extreme hydrological conditions associated with rainstorms, and to explore the results from different modeled scenarios surrounding the pollution threats associated with a sewage leak. A three-dimensional hydrodynamic water quality model was developed in this study. The model was calibrated and validated using observed data. The model results agreed well with the observed data, and the averaged relative root mean-squared error (RRMSE) for all of the compared variables was 33.3 %. The validated model was applied to analyze water quality responses for different extreme historical rainfall scenarios from January 1, 2012 to December 31, 2012. The model results indicate that for Lake Tianyinhu, rainstorms adversely affect water quality due to larger nutrient loads, generated by larger rainfall events, and the limited water storage capacity of the lake. Moreover, the responses of water quality to sewage leak events were studied through four scenarios with different leak intensities and durations. The model results indicate that sewage leaks have measureable negative effects on water quality and that it is vital to inspect and promptly eliminate any possible leaks within pipes surrounding the lake. This study may provide a useful tool for hydrological ecosystem protection and management techniques for similar urban lakes. 相似文献
455.
Pu R Gong P Tian Y Miao X Carruthers RI Anderson GL 《Environmental monitoring and assessment》2008,140(1-3):15-32
For monitoring and controlling the extent and intensity of an invasive species, a direct multi-date image classification method
was applied in invasive species (salt cedar) change detection in the study area of Lovelock, Nevada. With multidate Compact
Airborne Spectrographic Imager (CASI) hyperspectral data sets, two types of hyperspectral CASI input data and two classifiers
have been examined and compared for mapping and monitoring the salt cedar change. The two types of input data are all two-date
original CASI bands and 12 principal component images (PCs) derived from the two-date CASI images. The two classifiers are
an artificial neural network (ANN) and linear discriminant analysis (LDA). The experimental results indicate that (1) the
direct multitemporal image classification method applied in land cover change detection is feasible either with original CASI
bands or PCs, but a better accuracy was obtained from the CASI PCA transformed data; (2) with the same inputs of 12 PCs, the
ANN outperforms the LDA due to the ANN’s non-linear property and ability of handling data without a prerequisite of a certain
distribution of the analysis data. 相似文献
456.
土壤性质在出生缺陷环境风险中的指示作用 总被引:2,自引:0,他引:2
为研究土壤性质在出生缺陷环境风险中的指示作用,考虑了区域人口分布和疾病空间结构,使用Bayesian方法,对山西省和顺县连续4年的神经管畸形发生的数据进行了处理,并使用非参数统计的方法,结合土壤环境过程机理,对土壤的理化性质和出生缺陷的环境风险做了系统分析. 结果表明:土壤的机械组成,阳离子交换量(CEC),pH,有机质含量及碳酸钙含量都与神经管畸形发生率显著相关. 土壤砂粒含量高的地区,神经管畸形发生的风险会显著增加;土壤粘粒含量高的地区,神经管畸形发生的风险会显著降低. 土壤阳离子交换量高的地区,神经管畸形发生的风险会显著降低. 在偏碱性土壤且pH较高的地区,神经管畸形发生的风险会显著降低.在有利于土壤提供有效形态重金属及稀土元素的环境条件下,神经管畸形发生率会显著提高.在影响神经管畸形发生的环境因素中,土壤介质中各形态元素的有效含量比其总量具有更强的指示作用. 相似文献
457.
This study experimentally studied the dispersion of exhaled pollutant in the breathing microenvironment (BM) in a room equipped with a displacement ventilation (DV) system and indoor air stability conditions (i.e., stable and unstable conditions). The vertical temperature differences and the carbon dioxide (CO2) concentration in the BM were measured. Results show that when DV is combined with the stable condition (DS), pollutant tends to accumulate in the BM, leading to a high pollutant concentration in this region. Whereas, when DV is combined with the unstable condition (DU), pollutant diffuses to a relatively wider area beyond the BM, thus the pollutant concentration in the BM is substantially reduced. Moreover, increasing the flow rate can reduce the pollutant concentration in the BM of the DS but yields little difference of the DU. In addition, personal exposure intensity increases with time, and the DS has a relatively higher increase rate than DU. The results suggest that indoor air stability will affect the performance of DV systems. DS will lead to a higher health risk for people when they stay in the indoor environment with pollutant sources, and DU is recommended for minimizing pollutant level in the BM in order to reduce the pollutant concentration and providing better air environments for the occupants. 相似文献
458.
459.
Apolipophorin III, traditionally known for lipid transport in insects is fairly established as toxicity indicator against harmaline and tea saponin during this study. Apolipophorin III expressed in the hemolymph and midgut tissues of 3rd, 4th, 5th larval instars and pupae of Spodoptera exigua. Apolipophorin III presence was further confirmed by achieving its partial cDNA (Genbank accession no. FJ606822) of 448 bp. qRT PCR revealed that tea saponin resulted in significant reduction of gene expression in 3rd and 4th larval instars but increased in 5th instar as compared to control. Harmaline caused gradual increase of gene expression in 3rd, 4th and 5th instars after feeding on the treated diet. Fifth instar larvae synonymously resulted in the highest gene expressions against both the biochemicals. After the injection of harmaline and tea saponin abrupt increase in gene expression of 4th, 5th larval instar and pupae was observed as compared to control treatment. Transmission electron microscopy of midgut epithelium after being fed with harmaline and tea saponin depicted certain cytological changes. Harmaline treatment lead to cytoplasm vacuolization, mitochondrial disruption, spherocrystals with concentric layers, irregular nucleus and floating nuclei in cytoplasm. Tea saponin treatment resulted in denser cytoplasm, higher intracellular osmotic concentration and reduced complement of apical microvilli. Cells were found to have only a few mitochondria and glycogen deposits in comparison to control treatment. 相似文献
460.
Jian-Ping Guo Xiao-Ye Zhang Hui-Zheng Che Sun-Ling Gong Xingqin An Chun-Xiang Cao Jie Guang Hao Zhang Ya-Qiang Wang Xiao-Chun Zhang Min Xue Xiao-Wen Li 《Atmospheric environment (Oxford, England : 1994)》2009,43(37):5876-5886
Using one year of Aerosol Optical Depth (AOD) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite and particular matter (PM) contents measured at eleven sites located mostly in the eastern China in 2007, the relationship between columnar AOD and hourly and daily average (DA) PM were established. The peak AOD observed from MODIS was generally consistent with the surface PM measurements in eastern China, where Zhengzhou had the maximum annual mean PM10 of 182.1 μg m?3, while Longfengshan had the minimum annual mean of 38.1 μg m?3. Ground level observations indicated that PM concentration varies widely across different regions, which was mainly due to the difference in weather conditions and anthropogenic emissions. The coarse particles accounted for the main air pollution in Zhengzhou and Benxi whiles the fine particles, however, were the main constituents in other sites. Results showed that MODIS AOD (averaged over the box of 5 × 5 and 3 × 3 pixels) had a better positive correlation with the coincident hourly average (HA) PM concentration than with DA due to diurnal variation in PM mass measurements. After correcting AOD for relative humidity (RH), the correlation did not improve significantly, suggesting that the RH was not the main factor affecting the correlation of PM with AOD. The statistical regression analysis between MODIS AOD and PM mass suggested that the satellite-derived AOD is a useful tool for mapping PM distribution over large spatial domains. 相似文献