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21.
根据锦州市环境监测中心站的大气资料,通过对其3个采样点,从2001年到2010年共10年的监测数据进行综合分析,结果表明锦州地区酸雨多出现在5、6、7月,以SO42-、NO3-和NH4+、Ca2+为主要污染离子,体现了大气降水煤烟型污染的特点。通过对数据的综合分析,研究锦州市降水现状及发展变化趋势,分析了酸雨的成因并提出了酸雨控制的对策。 相似文献
22.
通过将比值法、主成分分析和正定矩阵分析法相结合对大气中PAHs的污染源进行了解析,结果表明,煤的燃烧和汽车尾气的排放是PAHs的主要污染源,冬季,煤的燃烧是主要污染源,其贡献率为60.6%,其次为汽车尾气排放(34.4%),其他季节,汽车尾气的排放和燃煤污染是主要的污染源,其贡献率分别为59.3%和17.1%。通过等效毒性当量因子计算得到,哈尔滨大气中BaP当量浓度冬季为7.751 9 ng/m3,其他季节为0.688 6 ng/m3,均符合中国规定的10 ng/m3。 相似文献
23.
The toxicity of naphthalene to a freshwater microalga, Chlorella pyrenoidosa, and the subsequent recovery of algae from the damage
were investigated under two nutrient conditions, either enriched with nitrogen (N) and phosphorus (P), or starved of N and P. Results
showed that C. pyrenoidosa was more sensitive to naphthalene under N,P-enriched condition, and the inhibitory rate generally increased
at first and then decreased gradually with the evaporation of naphthalene under both nutrient conditions. Enriched N, P reduced the
inhibitory rate at initial naphthalene concentration of 5 and 10 mg/L, but enhanced it at 100 mg/L, at which more severe ultrastructure
damages were found than those under N,P-starved condition. Observed damages included partly or totally disappearance of nucleolus,
nuclear, and plasma membranes. According to the chlorophyll content and cell density measurements, C. pyrenoidosa could recover
from naphthalene damage with initial concentrations 6 50 mg/L in 7 days under both nutrient conditions, while they could not recover
if the initial concentration of naphthalene was at 100 mg/L. Under the N,P-starved condition, the inability of C. pyrenoidosa to recover
from the naphthalene damage was consistent with the results of high inhibitory rate, low value of specific growth rate (SGR, 0.05
day??1), and the severe destruction of cell structure. However, under the N,P-enriched conditions, the observed lower inhibitory rate,
higher value of SGR (0.55 day??1), and the intact cell structure of most cells suggested that algae could potentially recover from the
naphthalene damage. 相似文献
24.
电旋风除尘模型实验研究 总被引:9,自引:0,他引:9
本研究试图将电除尘器与旋风除尘器组合为一体,以求取得较高的除尘效率,并利用旋转气流实现自动清灰。本文介绍了切向进气直流式电旋风除尘的模型试验,通过实测不同工况下的除尘效率和压力损失,应用经典除尘理论,建立了相应的数学模型。 相似文献
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26.
Imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitro-imidazolidin-2-ylideneamine] and RH-5849 [2'-benzoyl-l'-tert-butylbenzoylhydrazinel] are two pesticides used in China since 1992. In the present study we conducted acute toxicity test, micronucleus (MN) test and comet assay of the two pesticides on amphibian, Rana N. Hallowell, a sensitive organism suitable for acting as the bio-indicator of aquatic and agricultural ecosystems. The values of LC50-48 h of imidacloprid were found to be 165 mg l(-1) for tadpoles of Rana limnocharis and 219 mg l(-1) for tadpoles of Rana N. Hallowell. On the other hand, RH-5849 showed no acute toxicity to tadpoles during the 96 h exposure even it was saturated in the test solutions. There were significant differences in the MN frequencies between the negative controls and the treated groups at the dose of 8 mg l(-1) for imidacloprid (p < 0.05) and 40 mg l(-1) for RH-5849 (p < 0.01). Comet assay found significant differences (p < 0.01) in the distributions of DNA damage grades between the negative controls and groups treated in vitro with 0.05, 0.1, 0.2 and 0.5 mg l(-1) of imidacloprid and 5, 25, 50 and 100 mg l(-1) of RH-5849, respectively. DNA damage scores increased with the exposure levels of the two pesticides and dose-effect relationships were observed for both imidacloprid (r2 = 0.92) and RH-5849 (r2 = 0.98). The MN test and comet assay revealed potential adverse effects of the two pesticides on DNA in the erythrocytes of amphibians in aquatic and agricultural ecosystems. 相似文献
27.
The adsorption characteristics of heavy metals by various particle sizes of MSWI bottom ash 总被引:8,自引:0,他引:8
The incineration rate of municipal solid waste (MSW) has been increased because of difficulty in securing a proper disposal site for MSW in Korea. The advantage of incineration is reduction of the volume of waste; however, significant amounts of bottom ash and fly ash were generated in the incineration process. Their treatment has attracted growing interest because of the potential toxicity of hazardous heavy metals. Generally, heavy metals are less released from bottom ash than from fly ash. In this study the adsorption characteristics of heavy metals were investigated using various particle sizes of MSWI bottom ash. Since bottom ash has a broad particle size distribution, it was sieved to size classes of +20, -20, -48, -80, -100 mesh. Cation exchange capacity (CEC) was analyzed by the ammonium acetate method to evaluate the potential as an adsorbent. The CEC values and surface areas increase as the range of particle size becomes finer. The adsorption experiment was conducted using synthetic (Cu and Ni) and plating rinse water as a function of reaction time (10-180 min), liquid/solid ratio (2-100) and particle size (+20 to -100 mesh), respectively. The adsorption rate increased with decreasing particle size and with increasing liquid/solid ratio; however, the removal efficiency of Cu was higher than that of Ni. In the case of plating rinse water, the adsorption rate decreased sharply at high liquid/solid ratio, and it showed over 80% of adsorption rates for Cu and Ni at an initial pH of 3. 相似文献
28.
Analysis of microcystins in cyanobacteria blooms and surface water samples from Meiliang Bay,Taihu Lake,China 总被引:18,自引:0,他引:18
Shen PP Shi Q Hua ZC Kong FX Wang ZG Zhuang SX Chen DC 《Environment international》2003,29(5):641-647
Taihu Lake is the third largest freshwater lake in China. In recent years, the water pollution of cyanobacteria blooms has become a severe problem in this area. Microcystins (MCs) are an important group of toxic compounds mainly produced by some cyanobacteria species and have both acute and chronic hepatotoxic effects on animals and humans. This paper presents the first data on the identification and detection of MCs in both natural occurring cyanobacteria blooms and surface water samples (0-0.5 m), collected from Meiliang Bay, Taihu Lake, China. A conventional method for extraction and isolation of MCs from cyanobacteria blooms was applied. High-performance liquid chromatography (HPLC) analysis showed that the main toxic component in the cyanobacteria materials was MC-LR. The monoclonal antibody (mAb) against MC-LR produced by hybridoma technique was employed for direct competitive ELISA to detect the concentrations of MCs in bloom and water samples collected in 2001. The results not only revealed the presence of MCs but also temporal variations of MCs levels of three sampling stations in Meiliang Bay in 1 year. It is obvious that the MC contents were relatively higher during warm months and related with the status of eutrophication. Our study indicates the threat associated with MCs in water body of Taihu Lake. To prevent the MCs potential hazard on public health in this area, some necessary measures of monitoring and control of growth of cyanobacteria are urgently needed. 相似文献
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