Health risk assessment of heavy metals in Cyprinus carpio (Cyprinidae) from the upper Mekong River

The purposes of this research are to quantify the concentration of heavy metals (Zn, Cu, As, Pb, Cd, and Hg) in the water and fish tissues of common carp (Cyprinus carpio) in the upper Mekong River and to thereby elucidate the potential dietary health risks from fish consumption of local residents. Surface water and fish tissues (gill, muscle, liver, and intestine) from four representative sample areas (influence by a cascade of four dams) along the river were analyzed for heavy metal concentrations. Results revealed that the levels of heavy metals in fish were tissue-dependent. The highest Cu and As levels were found in the liver; the highest Zn and Pb levels occurred in the intestine, and the highest Hg level was found in the muscle. The total target hazard quotient (THQ) value for residents is > 1 for long-term fish consumption, and local residents are, therefore, exposed to a significant health risk. Results from the current study provide an overall understanding of the spatial and tissue distribution of heavy metals in water and fish body along the upper Mekong River under the influence of cascade dams and highlight the potential health risk of As for the local residents of long-term fish consumption.

     

不同浓度养殖废水对青萍生长能力的影响

为了探讨废水浓度对青萍(Lemna minor)净化能力、生物质和能量积累能力的影响,以猪场养殖废水为供试废水,分析了在不同废水浓度下青萍对废水中总氮(TN)、氨氮和总磷(TP)的净化能力,青萍的生长情况,以及青萍中碳(C)、氮(N)、磷(P)元素含量和热值的变化情况。研究表明,青萍在1%浓度的废水中表现出最高的污染物净化能力。虽然青萍的C、N、P含量和热值均随废水浓度的增加而增加,但是由于相对增长率以1%的废水中生长的青萍最高,青萍的最高生产力、C和能量的固定能力均出现在1%废水浓度培养的青萍中,其次是5%废水浓度培养的青萍。多项式回归分析表明,可以使青萍获得最大C和能量固定能力的废水浓度为3.4%,对应的氨氮浓度为26 mg/L,TP浓度为3.4 mg/L。研究结果为进一步优化高生物质生产、高污染物去除率的养殖废水-浮萍培养体系提供了一定的基础。     

混凝-生物强化联合处理环氧树脂高盐废水

环氧树脂高盐废水是目前较难处理的工业废水之一.采用混凝联合生物强化工艺:通过混凝过程进行预处理后,投加嗜盐菌进行生物强化考察盐度变化对系统降解有机物的影响以及污泥性状的变化情况.结果表明,当废水中氯离子浓度达到驯化目标10 g/L时,系统对COD的去除率仍稳定在85%左右;以没有投加嗜盐菌的反应器为对照组,在进水COD平均浓度为550 mg/L左右,氯离子浓度由12 g/L增至21 g/L时,对照组COD平均去除率由82%降至60%以下,而投加了嗜盐菌的反应器(投加组)则仍保持在85%以上;此外,盐度的变化同时影响污泥的活性及其沉降性能,随着盐度增大,两组中的污泥活性均有所降低,但投加组的污泥活性相对较高,其污泥的沉降时间和污泥体积指数(sludge volume index, SVI)值也较低.采用本工艺处理环氧树脂高盐废水,使得生物处理过程能够长期稳定运行,且能够保持较高的耐盐度和COD去除率.     

Contamination of organochlorine pesticides in water and sediments from a waterbird-inhabited lake,East Central China

Seventeen organochlorine pesticides (OCPs) were investigated in the water and sediments from a waterbird-inhabited lake (Yangchaihu Lake) to evaluate their current pollution levels and potential risks. The concentrations of total OCPs in water and sediments were 10.12–59.75 ng/l and 4.25–27.35 ng/g dry weight, respectively. Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the most abundant OCPs, while HCB and cyclodiene pesticides were detected with low levels. Levels of ∑OCPs (sum of 17 OCPs) at sites highly influenced by waterbirds were significantly higher than the sites with no significant waterbird populations (one-way ANOVA, P?相似文献   

Fractionation and speciation of arsenic in fresh and combusted coal wastes from Yangquan, northern China

In this study, the content and speciation of arsenic in coal waste and gas condensates from coal waste fires were investigated, respectively, using the digestion and sequential extraction methods. The fresh and fired-coal waste samples were collected from Yangquan, which is one of the major coal production regions in northern China. High-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) was used to determine the concentrations of four major arsenic species [As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsenic acid (DMA)] in the extracts, while ICP-MS was used to measure total As content. Arsenic content in the investigated coal wastes and the condensate ranges between 23.3 and 69.3 mg/kg, which are higher than its reported average content in soils. Arsenic in coal waste exists primarily in the residual fraction; this is followed in decreasing order by the organic matter-bound, Fe–Mn oxides-bound, exchangeable, carbonates-bound, and water-soluble fractions. The high content of arsenic in the condensates indicates that combustion or spontaneous combustion is one of the major ways for arsenic release into the environment from coal waste. About 15% of the arsenic in the condensate sample is labile and can release into the environment under leaching processes. The water extractable arsenic (WEA) in the fresh coal waste, fired coal wastes, and the condensate varied between 14.6 and 341 μg/kg, with As(V) as the major species. Furthermore, both MMA and DMA were found in fresh coal wastes, fired coal wastes, and the condensate.     

安钢高炉出铁场除尘工程实践

六号高炉炉前出铁场工程是一项工业污染治理项目，该项目结合安钢实际，利用较少的投资，解决了多年困扰炼铁厂的炉前烟尘污染的问题，该技术结合目前国内中小高炉出铁场综合治理的经验，提出了顶吸加侧吸的综合捕集方式，极大地改善了出铁场的烟尘污染状况，同时回收的粉尘又有极高的利用价值，取得了一定的经济效益。     

彩色玉米粉粉尘云最低引燃温度试验研究

利用HY16429粉尘云引燃温度试验装置,分别对5种彩色玉米粉在不同喷尘压力和不同质量浓度下进行粉尘云最低引燃温度的测定。结果表明:在不同的喷尘压力下,粉尘云最低引燃温度随粉尘云质量浓度增加先下降后上升,在2 250~3 500 g/m~3达到最危险浓度;在不同的质量浓度下,粉尘云最低引燃温度随喷尘压力增加先下降后上升,在60~80 k Pa达到最低值,表明当粉尘云形成的悬浮状态最佳时,最低引燃温度为360℃;无色玉米粉的引燃温度普遍低于含色素的玉米粉,表明色素的添加可使玉米粉的燃爆危险性降低,这与玉米粉粒度分布情况和所含元素中碳氮比有关,C元素含量和碳氮比越高所需引燃温度越低;无色玉米粉粒度分布相对分散且粉尘粒度相对较大,加入色素后粒度分布较集中且粉尘粒度相对较小;不同颜色的玉米粉最低引燃温度呈现不同的变化规律,可解释为色素的发色基团对应于不饱和双键的共轭体系,在受热时它的结构易发生变化所导致。     

基于SEM与员工感知的高速铁路人因安全影响机理研究

为了揭示环境因素、岗位质量、作业负荷对高速铁路人因安全的影响机理,在解析高速铁路人因安全内涵特征的基础上,建立高速铁路人因安全影响分析的结构方程模型。利用问卷调查采集实际数据,采用LISREL软件进行模型评价,以获取各个影响因素对高速铁路人因安全的影响机理。结果表明:环境因素、岗位质量、作业负荷对高速铁路人因安全的影响程度不同,岗位质量影响较明显影响系数达到0.68,岗位质量同时对作业负荷产生影响,影响系数达到0.67;人因安全管理水平、人因安全控制策略与岗位适应性的影响系数分别为0.91、0.85、0.96。     

爆炸事故及预防

为了促进我国的爆炸安全研究工作更深入发展,本文列出了利用爆炸激波管技术测定氢气、汽油、铝粉等可爆性物质的爆炸特性。研究表明:这些可爆性物质在一定条件都能形成破坏力极大的爆轰现象。实验确定了氢、汽油和氧混合物的可爆(轰)极限、可燃性极限、混合物临界初始压力等爆炸临界条件。控制可爆性物质的初始条件不超过其爆炸临界条件,能够防止爆轰或爆燃现象发生;添加不参加反应的物质(如氩气、氮气、水蒸汽等)能够使已达到爆炸条件的混合物阻爆。本文的数据可供有关部门参考。     

基于GPS的北京市2007-2012年地面沉降变化研究

利用经验模态分解(EMD)方法处理2007-2012年的北京GPS数据,并通过与地下水埋深比较分析近年来的地面沉降。首先通过2007-2012年的年沉降速率,发现北京沉降中心连片,形成了中东部的沉降漏斗。DSQI累积沉降量达到510 mm,DSQI、CHAO、NLSH三站点的年沉降速率分别为85 mm/a,41.7 mm/a和20mm/a。其次采用EMD方法提取DSQI、NLSH的垂向序列的趋势项,分析其沉降趋势。最后,对地下水埋深和GPS站点沉降趋势之间的关系进行了对比分析,地面沉降变化趋势与地下水水位变化具有较好的一致性,地下水水位变化是地面沉降发生发展的主要诱因。