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891.
The rural primary organizations of water management are the important parts of the public service system in the government administration.This paper studies several major management models of the rural primary water management in Zhejiang Province of China.The research result shows that ambiguous functions,lack of funding,and unreasonable personnel structure are the major problems of the rural primary water management.Therefore,it is urgent to improve service system,ensure sufficient funds,and qualify the population personnel of the rural primary organizations of water management 相似文献
892.
Xuebo Qin Nan Sun Lixin Ma Yingqiao Chang Liqiang Mu 《Environmental science and pollution research international》2014,21(18):11094-11098
In order to examine whether the leaves of the Colorado blue spruce (Picea pungens) are damaged or not by traffic pollution, the traits of the anatomy and physiology of its leaves are investigated by exposure to vehicle exhausts in a laboratory experiment lasting 30 days. The results show that both the anatomical structures and physiological traits of the leaves are significantly affected by vehicle exhausts. The anatomical structures, including epidermis, cuticle, palisade, and spongy parenchyma are modified when exposed to the high concentrations (≥0.4 mg/m3) of vehicle exhausts. However, physiological traits such as total chlorophyll content are not changed when exposed to different concentrations of vehicle exhaust. Unlike the total chlorophyll content, the electrical conductivities increased, whereas the POD activities decreased when presented in vehicle exhausts. The present study indicates that the Colorado blue spruce changes its anatomical structures and physiological traits to avoid possible damage by vehicle exhausts. 相似文献
893.
894.
Cytochrome P450s (CYPs) play a key role in the metabolism of a wide range of environmental xenobiotics and endogenous compounds. The expression and activity levels of CYPs can be elevated by a process of induction involving the activation of nuclear receptors. The effects of the ionic liquid 1-octyl-3-methylimidazolium chloride ([C8mim][Cl]) on the expression of cytochrome P450 members, including CYP1A1, CYP2E1, and CYP3A, as well as on aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) in mouse mammary carcinoma cells (EMT6) were investigated by using quantitative real-time PCR in the present study. The results reveal that [C8mim][Cl]-exposure up-regulates the expressions of CYP1A1, CYP2E1, and CYP3A at mRNA level, suggesting that imidazolium-based ionic liquids can activate CYPs. Our results also suggest that [C8mim][Cl]-mediated CYP3A induction be PXR-dependent. This result may be beneficial to evaluating the environmental toxicity of imidazolium-based ionic liquids and investigating the metabolism of imidazolium-derivative drugs. 相似文献
895.
拮抗菌对黄瓜枯萎病菌的室内生物活性 总被引:16,自引:0,他引:16
测定了从沤肥浸渍液和土壤中分离并筛选得到对黄瓜枯萎病菌的室内生物活性的6个菌株,编号为94-I、94-Ⅱ、94-Ⅲ、96-Ⅰ和98-Ⅱ,测定其孢子悬浮培养16h时对黄瓜枯萎菌的抑制率分别为48.29%、0.00%、60.69%、39.28%、61.29%和72.32%,孢子和菌丝有的变畸形并产生大泡囊;平皿拮抗试验表明,其活体浓度为50%时对黄瓜枯萎病菌的抑制率最大分别为74.52%、83.27%、90.60%、88.59%、89.35%和94.30%;而其相同浓度高压蒸汽灭活后的代谢产物对黄瓜枯萎病菌的抑制率最大分别为33.215、52.22%、62.84%、46.57%、47.61%和70.34%。 相似文献
896.
Phorate (O,O-diethyl S-ethylthiomethyl phosphorodithioate) dissolved in aqueous solution was almost completely decomposed by ozonation to form various species within 10 minutes of reaction time for the experimental conditions examined in this research. The generation rate of sulfate was found to be fairly independent of solution pH value. However, the formation of phosphate and carbonate was more favorable for alkaline solutions where hydroxyl free radical is the primary oxidative species. The reaction rates increased with initial gaseous ozone concentrations, indicating the reaction was mass transfer-controlled within the experimental range of this research. Combining the analytical results by various instruments, including gas chromatograph equipped with an electron ionization detector (GC-EID), high performance liquid chromatography (HPLC), ion chromatography (IC), and total organic carbon (TOC), the temporal sequence of phorate ozonation was proposed in this study. The oxidation of sulfur atoms on the phosphorus-sulfur double bond or carbon-sulfur-carbon bond by ozonation was found to occur at first to form sulfate and various intermediates. 相似文献
897.
In this paper, the movement behavior of Daphnia magna was studied as a bio-indicator of organophosphorous pesticide (OP) contamination, using an on-line bio-monitoring method, the Multispecies Freshwater Biomonitor. A static test of acute toxicity test revealed the 24-h and 48-h LC(50) values (95% confidence limit) for Daphnia magna to be respectively 0.45 microg/l and 0.21 microg/l for dipterex 3.80 microg/l and 0.90 microg/l for malathion, and 1.25 microg/l and 0.38 microg/l for parathion. The behavior strength of Daphnia magna was a sensitive indicator of sublethal OP stress and resulted in significant concentration-response relationships for the three OPs. Increasing OP concentration will result in more intensive behavioral responses of Daphnia magna and shorter response time, which could be described by the Stepwise Stress Model (SSM). Therefore movement behavior can be effectively applied in early warning of environment quality by on-line bio-monitoring. The intensive changes in behavior strength of Daphnia magna over a short time follow the SSM concept and can be used as an indicator of early stress response to OP accidental contamination. 相似文献
898.
Lu LT Chang IC Hsiao TY Yu YH Ma HW 《Environmental science and pollution research international》2007,14(1):49-59
Background Since the 1970s, at least 200 hectares (ha) of farmland has been polluted by the heavy metal cadmium (Cd).Consequently, the
Cd pollution has led to contaminate the rice production and caused acute social panic. According to the recent investigation
results performed by the Taiwan Environmental Protection Administration (TEPA), it is indicated that most of the Cd pollution
incidents in Taiwan resulted from the wastewater discharge of stearate Cd factories. To prevent the Cd pollution incidents
from spreading, the TEPA has either forced these factories to close down or assisted them in improving their production processes
since the 1980s. Unfortunately, accidental incidents of Cd pollution still emerge in an endless stream, despite the strict
governmental controls placed on these questionable factories. Whether this pollution has resulted from undetected or hidden
pollution sources stemming from two decades ago or comes from some new source, will be an outstanding issue. Therefore, this
study attempts to identify the pollution sources of Cd in soil in Taiwan as well as to find the solution to the above-mentioned,
outstanding issue by way of a methodology termed Material Flow Analysis (MFA).
Method logy. The MFA has proved to be a useful tool on providing quantitative information of the flow of substances through an economic
to an environmental system. Based upon the supply-and-demand theory of MFA, researchers have successfully conducted an overview
of the use of materials in many industries, the construction industry being one of these. Therefore, this study tries to establish
a set of analytical processes by way of MFA for identifying the pollution source of Cd in soil in Taiwan. In addition, the
spirit of Life Cycle Analysis (LCA) technique was also employed to identify the materials, and products should be ignored
as a crucial pollution source in this study.
Results and Discussion According to the MFA methodology applied in this study and on the basis of related studies performed by Taiwanese governmental
authorities, we arrive at the following analysis results: (1) the total amount of Cd from the economic perspective of material
and product flow was approximately 441.2 tons; (2) the wastewater directly discharged into irrigation water can be concluded
to be the major pollution route of Cd in farmland soil in Taiwan; (3) material plastic stabilizer (cadmium oxide, CdO), Zn-Pd
compounds and Cu compounds should be the crucial pollution sources to contaminate environment through the route of wastewater
in Cd flow analysis; (4) the crucial pollution sources to contaminate environment through the route of wastewater in Cd flow
analysis were five factories, Coin, Jili, Taiwan Dye, Guangzheng and Mingguan, and they were all categorized as stearate Cd
industries; (5) the typical source of the Cd pollution in soil in Changhua County through the pollution route of wastewater
should be the metal surfacing process industries.
Conclusions This study proved that MFA can be a good tool for identifying Cd flow as well as for recognizing the crux of the problem
concerning incidents of Cd pollution. This study led to the conclusion that the causal relationship between farmland pollution
caused by Cd and stearate Cd factories in Taiwan seemed quite close by way of MFA methodology. In addition, this study also
found that the wastewater discharged from a single metal surfacing process factory will not cause remarkable farmland pollution.
However, the wastewater simultaneously discharged from a group of pollution factories can result in a significant pollution
incident.
Recommendations and Outlook This case study is only a small contribution to the understanding of the toxic material flow related to Cd in the environment.
This study recommends that Taiwanese governmental authorities should not deal with problems on an ad hoc basis, but should
instead deal with Cd pollution problems overall employing control measures. Finally, the more accurate information or data
we can collect, the more reliable results we can identify. Therefore, the quality and quantity of related data used in this
MFA model should be closely scrutinized in order to ensure the most correct and comprehensive investigation on the toxic material
flow. 相似文献
899.
The Avoidance Responses of Daphnia magna to the Exposure of Organophosphorus Pesticides in an On-Line Biomonitoring System 总被引:1,自引:0,他引:1
Zong-Ming Ren Zhi-Liang Li Jin-Miao Zha Kai-feng Rao Mei Ma Zijian Wang Rong-Shu Fu 《Environmental Modeling and Assessment》2009,14(3):405-410
In this study, avoidance behavior of the freshwater cladoceran Daphnia magna Straus was used as indicator to assess the early stress of accidental organophosphorus pesticide (OP) contamination. The
movement behavior was detected by a multi-species biomonitoring system. There was obvious concentration–response relationship
between the OP stress and the behavioral response even at sublethal exposure. A rising OP stress resulted in a significant
decrease of response time to escape (RTE; p<0.05). In comparison of different OPs, it was found that there was a power regression between RTE and the toxic unit of OPs.
Therefore, the avoidance behavior of D. magna was a sensitive indicator of sublethal OP stress, and the power relationship could be used to predict the early warning thresholds
of more OPs in the on-line biomonitoring system. 相似文献
900.
Hexavalent chromium (Cr(VI)) is an acknowledged hazardous material in drinking waters. As such, effective monitoring and assessment of the risks posed by Cr(VI) are important analytical objectives for both human health and environmental science. However, because of the lack of highly sensitive, rapid, and simple procedures, a relatively limited number of studies have been carried out in this field. Here we report a simple and sensitive analytical procedure of flow injection analysis (FIA) for sub-nanomolar Cr(VI) in drinking water samples with a liquid core waveguide capillary cell (LWCC). The procedure is based on a highly selective reaction between 1, 5-diphenylcarbazide and Cr(VI) under acidic conditions. The optimized experimental parameters included reagent concentrations, injection volume, length of mixing coil, and flow rate. Measurements at 540 nm, and a 650-nm reference wavelength, produced a 0.12-nM detection limit. Relative standard deviations for 1, 2, and 10 nM samples were 5.6, 3.6, and 0.72 % (n?=?9), and the analysis time was <2 min sample?1. The effects of salinity and interfering ions, especially Fe(III), were evaluated. Using the FIA-LWCC method, different sources of bottled waters and tap waters were examined. The Cr(VI) concentrations of the bottled waters ranged from the detection limit to ~20 nM, and tap waters collected from the same community supply had Cr(VI) concentration around 14 nM. 相似文献