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521.
本工作从理论上分析了石灰(石)湿式洗涤法脱烟气中二氧化硫的化学原理并结合实验进行了该法的化学动力学特性、再碳酸化问题及洗涤液循环系统的研究,结果表明:净化器内洗涤温度控制在60℃以下,液气比大于40Kg/m3,洗涤液pH值控制在79的情况下,脱硫效果较佳  相似文献   
522.
Increased cancer incidence and mortality have been found among humans exposed to high levels of organochlorines (OCs), either accidentally or as industrial workers. In order to assess levels of OCs in Norwegian women north of the Arctic Circle and validate self-reported fish consumption as a surrogate measure of organochlorine body burden, concentrations of seven polychlorinated biphenyl (PCB) congeners [IUPAC Nos. CB-105, CB-118, CB-138 (+ CB-163), CB-153, CB-180, CB-183, CB-187], beta-hexachlorocyclohexane (beta-HCH), 2,2'-bis(p-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE) and cis- and trains-chlordane (c-CD and t-CD) were examined in plasma samples of middle-aged women attending for health screening. Altogether, 47 of those invited (81%) completed a questionnaire and donated a suitable blood sample. The ability of questionnaire data to predict plasma levels of OCs was tested in linear and logistic regression analyses. Measured plasma concentrations were in the range reported for the general female population of other Western countries and the relative amounts of PCBs were similar to the circumpolar pattern. Intake of seagulls' eggs was a predictor of PCB congeners CB-138 (+CB-163) (p<0.05) and CB-153 (p<0.01). No other food category was positively associated with any compound. In contrast, duration of residence in the study municipality, body mass index (BMI) and lifetime lactation (months) were the best univariate predictors. There was an increase in beta-HCH, p,p'-DDE and most of the PCBs (p<0.05 for all) with increasing length of time a subject had lived in the municipality. BMI was a positive predictor for beta-HCH (OR=3.10, 95% CI 1.50-6.43, per 5 kgm(-2)), chlordane (OR=2.13, 95% CI 1.12-4.05, per 5 kgm(-2)) and CB-105 and CB-153 (p<0.05 for both). Lactation was negatively associated with all OCs (p<0.05), except chlordane and two of the PCB congeners. Time living in the municipality and lactation explained 34%, of the variance in concentration of total PCB in a multivariate model (p<0.001). The results indicate that regular consumption of fish (mostly lean species) from the Norwegian waters is not associated with an increased body burden of OCs (e.g., of importance to cancer development), although they confirm that lactation is the most important elimination route of these contaminants in women.  相似文献   
523.
为探讨近百年来抚仙湖不同湖区沉积物中有机碳埋藏及其来源变化特征,以抚仙湖南北部沉积柱为研究对象,分析有机碳埋藏速率时空变化特征,利用正构烷烃及其分布特征对埋藏在沉积物中的有机碳来源进行解析.结果显示,抚仙湖沉积物中有机碳含量为1.79~29.39mg/g,有机碳埋藏速率为3.07~27.71g/(m2·a),两者均随时间的增加呈现整体上升的趋势,1980年以来增长速度明显加快;沉积物中有机碳含量北部(8.70mg/g)小于南部(12.59mg/g),但有机碳埋藏速率北部(13.54g/(m2·a))大于南部(8.29g/(m2·a)),这与抚仙湖南北部有机质来源类型及人类活动的加剧造成的流域环境变化有关;抚仙湖沉积物中正构烷烃碳数范围为C12~C33,整体以高碳数组分为主,奇偶优势明显,表明沉积物中有机质主要来源于高等植物,Paq指示水生植物中以沉水植物占主导优势,2C31/(C27+C29)与ACL27~33指示陆生高等植物来源中,草本植物与木本植物的贡献相当,水生植物在北部湖区贡献大于南部,陆生高等植物在南部湖区的贡献大于北部.  相似文献   
524.
采用高通量测序-分子鉴定分级技术于2018年对大长山岛临近海域微藻粒级结构进行了研究,同时探讨了叶绿素a分级法测算微藻粒级结构的误差.结果发现,叶绿素a分级法测算微微型藻类(< 3μm)误差高达82%,严重低估了小粒径微藻的组成,分子鉴定分级法测算春季小粒径微藻生物量组成平均为86%,夏季平均为52%,秋季平均为20%.春季优势种抑食金球藻生物量占41%,夏季优势种金牛微球藻生物量占21%,这2种微微型藻类会严重影响滤食性贝类正常摄食生长,养殖风险较高.总氮、总磷、溶解硅等环境因子和贝类摄食的下行效应影响着该海域微藻粒级结构的变化.  相似文献   
525.
养殖场沼液中雌激素排放特征及去除效果研究   总被引:1,自引:0,他引:1  
为探究典型奶牛养殖场沼液中类固醇雌激素的排放特征,采用固相萃取-高效液相色谱串联质谱(SPE-HPLC-MS/MS)分析方法,对重庆市某奶牛养殖场厌氧池和好氧池出水中类固醇雌激素进行夏、秋、冬3季连续监测.结果表明:类固醇雌激素(含雌酮;17α-雌二醇;17β-雌二醇;雌三醇;硫酸雌酮)在厌氧池和好氧池出水中总浓度分别在347.28~2117.65ng/L和10.75~1070.00ng/L之间,其中厌氧池出水以雌酮(E1)、17α-雌二醇(17α-E2)和17β-雌二醇(17β-E2)为主,好氧池出水以E1和17β-E2为主.研究显示:好氧处理对E1、17β-E2、17α-E2的平均去除率达85.70%、56.82%、57.32%,厌氧处理可有效去除硫酸雌酮(E1-3S).在微生物作用下,厌氧和好氧处理均存在E1、17α-E2和17β-E2的相互转化,但雌三醇(E3)的低检出率则显示体系中雌激素转化为E3的比例较低.对雌激素活性(EEQ95th)的评估显示厌氧-好氧处理后雌激素活性平均降低70.34%,但沼液的雌激素生态环境风险仍不可忽视,需持续观察及研究.  相似文献   
526.
介绍目前环境应急监测的发展现状,以及对今后应急监测建设的建议。  相似文献   
527.
城市污水管网污染物沉积与冲刷释放规律研究   总被引:1,自引:0,他引:1  
为明确城市污水管网中污染物沉积、冲刷释放及微生物降解作用对有机物去除的贡献,以管网中城市污水为研究对象,通过建立有沉积与无沉积的模拟管道,在首次冲刷的理论基础上得到管道污染物沉积释放计算模型,进而研究了不同流量下有机污染物的沉积与冲刷释放规律,并对不同流量下进出水的粒径分布及颗粒组成进行分析。结果表明,在管道6 h水力循环条件下,当流速为0.32 m/s时,污水中有机物变化以沉积贡献为主;当流速增加为管网最小设计流速0.6 m/s时,污染物沉积现象得到显著改善,冲刷释放效应增强;当流速进一步增加为0.9 m/s时,冲刷释放成为主要作用,生物降解作用微弱。  相似文献   
528.
Our objectives in this article are twofold: first, to use the analytical hierarchy process (AHP) to establish core priorities and, second, to discuss how to reorganize an environmental, health, and safety (EHS) department in a manner that will avoid “scope creep,” as well as inconsistencies in the delivery of client services as a result of personnel loss or change. The approach we describe is novel because it allows users to prioritize their actions daily and annually to recalibrate priorities.  相似文献   
529.
龙门山地震带及其附近有三类地震系列,它们是小震系列、强震系列与大震系列,都满足前震系列公式:Ni=Ni-k/(1-b)k(其中N为地震频度,i为脚指数,k为方次,b为地震频度的变化率)。该公式的意义在于由已知的地震频度推导出未知频度,进而推导出地震的发生周期。使用该公式预测龙门山地震带未来大震发生的时间是十分有意义的。  相似文献   
530.
Air pollution is a major obstacle to future sustainability, and traffic pollution has become a large drag on the sustainable developments of future metropolises. Here, combined with the large volume of real-time monitoring data, we propose a deep learning model, iDeepAir, to predict surface-level PM2.5 concentration in Shanghai megacity and link with MEIC emission inventory creatively to decipher urban traffic impacts on air quality. Our model exhibits high-fidelity in reproducing pollutant concentrations and reduces the MAE from 25.355 µg/m3 to 12.283 µg/m3 compared with other models. And identifies the ranking of major factors, local meteorological conditions have become a nonnegligible factor. Layer-wise relevance propagation (LRP) is used here to enhance the interpretability of the model and we visualize and analyze the reasons for the different correlation between traffic density and PM2.5 concentration in various regions of Shanghai. Meanwhile, As the strict and effective industrial emission reduction measurements implementing in China, the contribution of urban traffic to PM2.5 formation calculated by combining MEIC emission inventory and LRP is gradually increasing from 18.03% in 2011 to 24.37% in 2017 in Shanghai, and the impact of traffic emissions would be ever-prominent in 2030 according to our prediction. We also infer that the promotion of vehicular electrification would achieve further alleviation of PM2.5 about 8.45% by 2030 gradually. These insights are of great significance to provide the decision-making basis for accurate and high-efficient traffic management and urban pollution control, and eventually benefit people's lives and high-quality sustainable developments of cities.  相似文献   
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