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451.
Thirty-three air samples were collected by high-volume samplers from May 2007 to June 2008 in the coastal area of southwest Taiwan and analyzed for total suspended particulates (TSP) and polycyclic aromatic hydrocarbons (PAHs). Concentrations of TSP and total PAHs ranged from 40.4 to 251 μg m(-3) and 1.86-56.4 ng m(-3), respectively. Except for joss paper burning during the religious celebration of Ghost Month, which resulted in the highest concentration of PAHs in the summer of 2007, a seasonal variation in total PAH concentration was observed over this study period, with the highest concentrations in winter and the lowest in summer. Because of the geographical and climatic characteristics of the sampling site, monsoon activities modulate the seasonal variations of PAHs. Diagnostic ratios showed that PAHs in the atmosphere of the Kaohsiung coastal area arose predominantly from vehicle emissions (mainly from diesel exhaust), joss paper burning, and coal/wood combustion. The results of hierarchical cluster analysis (HCA) and principal component analysis (PCA) indicated that the sampling days could be divided into three groups and that the major source identification of PAHs was the same as the identification by diagnostic ratios. In addition, the results of HCA and PCA suggest that the samples collected with a prevailing northerly or northeasterly wind direction contain both local emissions and those from neighboring sources. On the other hand, the cases related to westerly or northwesterly winds indicated that local emission was the major source for the sampling site. 相似文献
452.
Is selenium deficiency really the cause of Keshan disease? 总被引:1,自引:0,他引:1
Keshan disease (KD) is a dilated cardiomyopathy closely related with a diet deficient in the mineral selenium. It is named for the northeastern Chinese county Keshan, where the disease prevalence is high because of selenium-deficient soil. KD is a gene–environment interaction disease. Here, we used stepwise multiple regression analysis to analyze the risk factors of the disease and the main clinical features in 71 KD patients and 290 controls. The variables analyzed included age, sex, family history of KD, blood selenium level, glutathione peroxidase-1 (GPx-1) activity, variance at codon198 in GPx-1 gene, residence in an endemic area, abnormal electrocardiography (ECG) findings, and cardiothoracic (CT) ratio. The main risk factors found were low GPx-1 activity, family history of KD and living in an endemic area. The main clinical features were increased cardiac load on ECG and increased CT ratio and Tei index. Public health and clinical prevention efforts could focus on increasing GPx-1 activity to address KD. Is selenium deficiency really the certain cause of KD? This is not at all a settled question. And further study is promptly required to investigate the etiology of KD. 相似文献
453.
Although prey-detecting and searching abilities of predatory leeches of rhynchobdellid or the Erpobdelliformes of arhynchobdellid
species have been studied in the past, hirudiniformes leeches are rarely mentioned. In this study, we investigated the chemosensory
ability for prey-detecting and searching in Whitmania laevis, a hirudiniformes species that mainly preys on freshwater snails, and examined if such ability aided in their prey selection.
Five sympatric snail species, i.e., apple snail Pomacea canaliculata, thiarid snail Thiara tuberculata, viviparid snail Sinotaia quadrata, ear pond snail Radix auricularia swinhoei and tadpole snail Physa acuta were used as prey. Our results showed that W. laevis has the chemosensory ability to detect the waterborne odors of snails. However, they follow the snails by their mucus trails,
and not by the odor that the snails leave in the water. Of these five snail species, W. laevis only followed the trails of the thiarid snails, ear pond snails and tadpole snails, and did not show a different response
to the trails produced by snails of different sizes. Our results suggest that W. laevis can use waterborne odors to detect the existence of prey. They rely on mucus trails to follow their preferred prey, but do
not distinguish between snails of a preferred size by their mucus trails. In addition, when following the trail of a preferred
snail, W. laevis exhibits a newly described searching behavior, i.e., head tapping, and may use it to locate a snail trail and increase its
probability of finding the trail-laying snail nearby. 相似文献
454.
455.
Huy Lai Nguyen Oanh Nguyen Thi Kim Phuc Nguyen Hong Nhung Chu Phuong 《Environmental science and pollution research international》2021,28(9):10678-10695
Environmental Science and Pollution Research - Local questionnaire surveys were conducted to collect representative activity data for calculation of annual emissions from residential combustion in... 相似文献
456.
The Phan Cong Jain Vipin Purnomo Eko Priyo Islam Md. Monirul Mughal Nafeesa Guerrero John William Grimaldo Ullah Sana 《Environmental science and pollution research international》2021,28(46):65150-65159
Environmental Science and Pollution Research - The “environment” has become one of the important and debatable topics of the world and policymakers identifying the new predictors of CO2... 相似文献
457.
肉联厂废水具有高生物降解性,其水质及排放量随季节变化很大,一般的小型肉联厂不能承担传统的处理方法,本文所述工程为应用厌氧接触发酵-稳定塘工艺,以及用新型过滤材料,取得了显著的效果,为处理小型肉联厂废水提供了一个良好的范例。 相似文献
458.
洞庭平原褐家鼠种群动态和繁殖特性 总被引:8,自引:1,他引:7
褐家鼠是洞庭平原稻作区的主要害鼠之一,在房舍区数量动态复杂,季节消长基本上属春冬双峰型,在农田区数量季节消长为夏秋双峰型。褐家鼠总雌性比为52.0%,全年繁殖.3~10月为繁殖盛期,盛期平均怀孕率为34.91±8.69%,平均胎仔数为8.2±l.0,4、7、9月出现怀孕高峰,11月至翌年2月为繁殖低潮期。褐家鼠在洞庭平原70年代数量较低,80年代初暴发成灾,80年代后期数量有逐步下降趋势。针对种群特征,提出了控制褐家鼠种群数量的对策。 相似文献
459.
安康“83.8”洪水灾害及防汛工作简析 总被引:2,自引:2,他引:0
本文对安康“83.8”洪水灾害形成的机理及人为因素进行论述,并对洪水造成的灾害和灾后的教训及作法作了阐述。 相似文献
460.
Xiang Gao Yongxin Zhang Cong Luo Yan Lu You Zhang Can Zhou Zhiying Zhou Xuecheng Wu Chenghang Zheng 《环境科学学报(英文版)》2023,123(1):270-280
The implementation of ultra-low emission (ULE) limits (SO2: 35 mg/m3, NOx: 50 mg/m3, PM: 10 mg/m3) promoted the development of flue gas treatment technologies in China. Pollutant control technology development for Chinese coal-fired power plants was summarized and an analysis of the applicability and cost of pollutant control technologies was conducted. Detailed data were collected from 30 ultra-low emission coal-fired units across China. Based on a cost analysis model, the average unit power generation incremental costs were 0.0144 and 0.0095 CNY/(kW·hr) for SO2 and NOx control technologies, respectively. The unit power generation incremental cost of twin spray tower technology was 7.2% higher than that of dual-loop spray tower technology. The effect of key parameters on operating cost was analyzed. The unit power generation incremental cost increased because of increments in the electricity price for SO2 control technology and the price of the reductant in NOx control technology. With high sulfur content or NOx concentration, the unit power generation incremental cost caused by pollutant control increased, whereas the unit pollutant abatement cost decreased. However, the annual operating hours or load increased, thereby leading to a decline in unit power generation incremental cost and unit pollutant abatement cost. 相似文献