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151.
荷兰浅水湖的生态恢复实践 总被引:3,自引:0,他引:3
湖泊的富营养化导致了湖泊生态系统的失衡。要使湖泊获得生态恢复,只通过控制入湖的营养负荷是不够的。荷兰的实践证明,外部营养负荷的大量减少并没有带来预期的恢复效果,而通过湖泊的换水和生物控制,湖泊的透明度、水生植物等得到了迅速改善。根据荷兰方面提供的资料,介绍了荷兰通过换水和生物控制进行浅水湖的生态恢复实践和取得的经验。 相似文献
152.
Ren Jilong Ma Hongjing Liu Ying Ruan Yunjie Wei Chenzheng Song Jing Wu Yinghai Han Rui 《Environmental science and pollution research international》2021,28(24):30807-30820
Environmental Science and Pollution Research - Aerobic denitrifiers have the potential to reduce nitrate in polluted water under aerobic conditions. A salt-tolerant aerobic denitrifier was newly... 相似文献
153.
Assessment of fates of estrogens in wastewater and sludge from various types of wastewater treatment plants 总被引:1,自引:0,他引:1
We measured five estrogens in the wastewater samples from the municipal wastewater treatment plants (M-WWTPs), livestock wastewater treatment plants (L-WWTPs), hospital WWTPs (H-WWTPs) and pharmaceutical manufacture WWTPs (P-WWTPs) in Korea. The L-WWTPs showed the highest total concentration (0.195-10.4 μg L−1) of estrogens in the influents, followed by the M-WWTPs (0.028-1.15 μg L−1), H-WWTPs (0.068-0.130 μg L−1) and P-WWTPs (0.015-0.070 μg L−1). Like the influents, the L-WWTPs (0.003-0.729 μg L−1) and the M-WWTPs (0.001-0.299 μg L−1) also showed higher total concentration of estrogens in the effluents than the H-WWTPs (0.002-0.021 μg L−1) and P-WWTPs (0.011 μg L−1 in one sample). The L-WWTPs (37.5-543 μg kg−1, dry weight) showed higher total concentrations in sludge than the M-WWTPs (3.16-444 μg kg−1, dry weight) like the wastewater. The distribution of estrogens in the WWTPs may be affected by their metabolism in the human body, their transition through biological treatment processes, and their usage for livestock growth. Unlike the concentration results, the daily loads of estrogens from the M-WWTPs were the highest, which is related to the high capacities of WWTPs. 相似文献
154.
155.
Scott W. Stine Inhong Song Christopher Y. Choi Charles P. Gerba 《Food and environmental virology》2011,3(2):86-91
The purpose of this study was to quantify the transfer of viral and bacterial pathogens in water used to dilute pesticides
sprayed onto the surfaces of cantaloupe, iceberg lettuce, and bell peppers. The average percent transfer of bacteria was estimated
to range from 0.00021 to 9.4%, while average viral transfer ranged from 0.055 to 4.2%, depending on the type of produce. Based
on these values the concentrations of hepatitis A virus (HAV) and Salmonella in water necessary to achieve a 1:10,000 annual risk of infection were calculated. Under worst case scenario assumptions,
in which a pesticide is applied on the same day that the produce is harvested and when maximum transfer values are used, concentrations
of 1.5 × 10−3 CFU Salmonella or 2.7 × 10−7 MPN HAV per 100 ml of the water used for application would result in 1:10,000 annual infection risk to anyone who consumes
the fresh produce. If harvesting does not occur until at least 14 days after the application, to produce the same risk of
infection, the numbers of Salmonella in 100 ml of water used to dilute the pesticides will be greater by up to five orders of magnitude, while the HAV numbers
will have increased by up to two orders of magnitude. Based on the reported concentrations of enteric viruses in surface and
ground waters in the United States, a 1:10,000 annual risk of infection could easily be exceeded with some groundwater sources
used in the United States. To reduce the risks associated with the consumption of fresh produce, water used to prepare pesticides
in spray applications should be evaluated for its microbiological quality. 相似文献
156.
可见光下氮掺杂二氧化钛对巯基苯并噻唑的降解 总被引:1,自引:1,他引:1
光降解反应中为了有效地利用可见光,以氨水为氮源,采用溶胶凝胶法在温和条件下制备出黄色氮掺杂二氧化钛。分别采用XRD、TEM、XPS和UV-Vis漫反射光谱对样品进行了表征。结果表明,所制备的样品均为锐钛矿相,晶粒随N/Ti配比的增加而增大;氮掺杂进入二氧化钛晶格中使可见光吸收增强。为控制水处理过程中的气味问题,以巯基苯并噻唑为探针,考察了氮掺杂二氧化钛的可见光活性。结果显示氮掺杂二氧化钛在可见光照射下可使巯基苯并噻唑的降解率为商用二氧化钛DegussaP-25的3倍。此外,存在一个最佳N/Ti配比显示出最高的可见光活性。 相似文献
157.
Changes of organic acid exudation and rhizosphere pH in rice plants under chromium stress. 总被引:1,自引:0,他引:1
Fanrong Zeng Song Chen Ying Miao Feibo Wu Guoping Zhang 《Environmental pollution (Barking, Essex : 1987)》2008,155(2):284-289
The effect of chromium (Cr) stress on the changes of rhizosphere pH, organic acid exudation, and Cr accumulation in plants was studied using two rice genotypes differing in grain Cr accumulation. The results showed that rhizosphere pH increased with increasing level of Cr in the culture solution and with an extended time of Cr exposure. Among the six organic acids examined in this experiment, oxalic and malic acid contents were relatively higher, and had a significant positive correlation with the rhizosphere pH, indicating that they play an important role in changing rhizosphere pH. The Cr content in roots was significantly higher than that in stems and leaves. Cr accumulation in plants was significantly and positively correlated with rhizosphere pH, and the exudation of oxalic, malic and citric acids, suggesting that an increase in rhizosphere pH, and exudation of oxalic, malic and citric acid enhances Cr accumulation in rice plants. 相似文献
158.
159.
160.
应用Fluent6.3标准k-ε方程对露天堆场周围空气流场进行数值模拟;计算来流风速6 m/s工况下,孔隙率为0、0.2、0.3、0.4、0.6、1时,抑尘网及料堆前后不同断面处风速的垂直分布及不同高度空气压力系数分布。结果表明,抑尘网网前1倍网高范围内,风速廓线受抑尘网影响显著,风速较无网工况最大降幅62.9%,且风速降幅随孔隙率增大而减小;抑尘网和料堆间区域,风速沿垂直高度非单调一致变化,30 m以下风速较无网工况小,30 m以上较无网工况大;堆后2倍堆高范围内,12 m高度以下处于回流区,风速较无网工况时大,12 m以上处于主流区,风速较无网工况时小;堆后3倍堆高距离外,各孔隙率风速廓线与无网工况一致。压力系数分布显示:网前3倍网高 (66 m)至堆后3倍堆高 (51 m)间压力系数变化显著,尤其在抑尘网处压力系数梯度大;孔隙率小于0.3时,迎风面负压最大,孔隙率大于0.4时,冠顶负压最大,至孔隙率为0.6时,料堆高度压力系数分布与无网工况一致。综合风速衰减和压力系数分布,孔隙率为0.2~0.4时,抑尘网遮蔽效果最佳。 相似文献